text:
... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady or as ... fall-related injuries, such as hip fracture. Some balance problems are due to problems in the inner ...
Directory of Open Access Journals (Sweden)
Muhammad Aslam Noor
Full Text Available We consider a new class of equilibrium problems, known as hemiequilibrium problems. Using the auxiliary principle technique, we suggest and analyze a class of iterative algorithms for solving hemiequilibrium problems, the convergence of which requires either pseudomonotonicity or partially relaxed strong monotonicity. As a special case, we obtain a new method for hemivariational inequalities. Since hemiequilibrium problems include hemivariational inequalities and equilibrium problems as special cases, the results proved in this paper still hold for these problems.
Explaining the Mind: Problems, Problems
Harnad, Stevan
The mind/body problem is the feeling/function problem: How and why do feeling systems feel? The problem is not just "hard" but insoluble (unless one is ready to resort to telekinetic dualism). Fortunately, the "easy" problems of cognitive science (such as the how and why of categorization and language) are not insoluble. Five books (by Damasio, Edelman/Tononi...
... in Chinese 繁體中文 ) What Are Knee Problems? (in Korean 한국어 ) What Are Knee Problems? (in Vietnamese bằng ... the knee. Ultrasound. A technique that uses sound waves to produce images of the soft tissue structures ...
DEFF Research Database (Denmark)
Skovhus, Randi Boelskifte; Thomsen, Rie
This article introduces a method to critical reviews and explores the ways in which problems have been formulated in knowledge production on career guidance in Denmark over a 10-year period from 2004 to 2014. The method draws upon the work of Bacchi focussing on the 'What's the problem represented...... to be' (WPR) approach. Forty-nine empirical studies on Danish youth career guidance were included in the study. An analysis of the issues in focus resulted in nine problem categories. One of these, 'targeting', is analysed using the WPR approach. Finally, the article concludes that the WPR approach...... provides a constructive basis for a critical analysis and discussion of the collective empirical knowledge production on career guidance, stimulating awareness of problems and potential solutions among the career guidance community....
Full Text Available ... can have intercourse but experience vaginismus during pelvic exams. Although vaginismus is considered a pain disorder, most ... and are used together to treat a problem. Education is important in understanding the anatomy and physiology ...
Full Text Available ... to a specialist trained in the diagnosis and treatment of sexual problems. This specialist may be a ... in many different ways. Often, multiple types of treatment may be required and are used together to ...
... For Consumers Consumer Information by Audience For Women Sleep Problems Share Tweet Linkedin Pin it More sharing ... PDF 474KB) En Español Medicines to Help You Sleep Tips for Better Sleep Basic Facts about Sleep ...
Full Text Available ... pain disorders. If you are experiencing problems viewing this embedded video, please click here . Transcript Disorders of ... no sexual fantasies and desire for sexual activity. This lack of desire is beyond what normally happens ...
... problems can lead to ED, such as: Poor communication with your partner Feelings of doubt and failure Stress, fear, anxiety, or anger Expecting too much from sex. This can make sex a task instead of ...
Full Text Available ... a problem. Education is important in understanding the anatomy and physiology of sex and in having realistic ... lubricants in that they are absorbed into the skin. Moisturizers are a "maintenance therapy" that is applied ...
... Inverted nipple; Nipple problems Images Female breast Intraductal papilloma Mammary gland Abnormal discharge from the nipple Normal ... 8. Read More Breast cancer Endocrine glands Intraductal papilloma Update Date 11/16/2014 Updated by: Cynthia ...
Full Text Available ... Smoking Cessation Links to Professional Societies and Organizations Home › Sexual Problems Sexual concern causing distress can be ... Find a Health Care Provider Back to Top Home | About Us | Reproductive Health Topics | News & Publications | Resources ...
Full Text Available ... sexual arousal disorder have little or no genital responsiveness to stimulation and they don't produce adequate ... problems. This specialist may be a physician, psychologist, social worker, or physical therapist. You may also find ...
... the home Dry mouth during cancer treatment Enteral nutrition - child - managing problems Gastrostomy feeding tube - bolus Jejunostomy feeding tube Mouth and neck radiation - discharge Multiple sclerosis - discharge Stroke - discharge Update Date 5/15/2014 ...
... much higher rates of foot problems. For women, pain in the toes and ball of the foot is much more common than in men, and it gets worse with age. However, pain in the heel tends to decrease as we ...
Full Text Available ... Some women with vaginismus can tolerate a pelvic examination, while some women can have intercourse but experience ... and are used together to treat a problem. Education is important in understanding the anatomy and physiology ...
Galin, Lev Aleksandrovich
L.A. Galin's book on contact problems is a remarkable work. Actually there are two books: the first, published in 1953 deals with contact problems in the classical theory of elasticity; this is the one that was translated into English in 1961. The second book, published in 1980, included the first, and then had new sections on contact problems for viscoelastic materials, and rough contact problems; this section has not previously been translated into English. In this new translation, the original text and the mathematical analysis have been completely revised, new material has been added, and the material appearing in the 1980 Russian translation has been completely rewritten. In addition there are three essays by students of Galin, bringing the analysis up to date.
Full Text Available ... problems. This specialist may be a physician, psychologist, social worker, or physical therapist. You may also find ... aids include lubricants, moisturizers, and sexual toys. Lubricants work by reducing friction between tissues. Many different types ...
DEFF Research Database (Denmark)
Christensen, Anders Bøggild; Rasmussen, Tove; Bundesen, Peter;
Sociale problemer kan betragtes som selve udgangspunktet for socialt arbejde, hvor ambitionen er at råde bod på problemerne og sikre, at udsatte borgere får en bedre tilværelse. Det betyder også, at diskussionen af sociale problemer er afgørende for den sociale grundfaglighed. I denne bog sætter en...
Kellerer, Hans; Pisinger, David
Thirteen years have passed since the seminal book on knapsack problems by Martello and Toth appeared. On this occasion a former colleague exclaimed back in 1990: "How can you write 250 pages on the knapsack problem?" Indeed, the definition of the knapsack problem is easily understood even by a non-expert who will not suspect the presence of challenging research topics in this area at the first glance. However, in the last decade a large number of research publications contributed new results for the knapsack problem in all areas of interest such as exact algorithms, heuristics and approximation schemes. Moreover, the extension of the knapsack problem to higher dimensions both in the number of constraints and in the num ber of knapsacks, as well as the modification of the problem structure concerning the available item set and the objective function, leads to a number of interesting variations of practical relevance which were the subject of intensive research during the last few years. Hence, two years ago ...
... with your sexual partner. Because they are complex, sexual concerns are treated in many different ways. Often, multiple types of treatment may be required and are used together to treat a problem. Education is important in understanding the anatomy and physiology ...
Full Text Available ... important to note that psychological problems such as sexual abuse can be involved as well. Pain caused by lack of lubrication or by vaginismus is not included in this ... woman wants sexual penetration. Women with this condition can still achieve ...
... Home & Community Home › Aging & Health A to Z › Kidney Problems Font size A A A Print Share Glossary Basic Facts & ... The kidneys also help maintain body fluids at normal levels. In addition, the kidneys play important roles in controlling blood pressure and ...
International Nuclear Information System (INIS)
Although there were not reasons to deplore against major activity release from any of the 110 industrial reactors authorized to operate in US, the nuclear incident that occurred at the Three Mile Island Plant in 1979 urged the public conscience toward the necessity of readiness to cope with events of this type. The personnel of the Emergency Planning Office functioning in the frame of US Department of Agriculture has already participated in around 600 intervention drillings on a federal, local or state scale to plan, test or asses radiological emergency plans or to intervene locally. These exercises allowed acquiring a significant experience in elaborating emergency plans, planning the drillings, working out scenarios and evaluation of the potential impact of accidents from the agricultural point of view. We have also taken part in different international drillings among which the most recent are INEX 1 and RADEX 94. We have found on these occasions that the agricultural problems are essential preoccupations in most of the cases no matter if the context is international, national, local or of state level. The paper poses problems specifically related to milk, fruits and vegetables, soils, meat and meat products. Finally the paper discusses issues like drilling planning, alarm and notification, sampling strategy, access authorizations for farmers, removing of contamination wastes. A number of social, political and economical relating problems are also mentioned
Class and Home Problems: Optimization Problems
Anderson, Brian J.; Hissam, Robin S.; Shaeiwitz, Joseph A.; Turton, Richard
Optimization problems suitable for all levels of chemical engineering students are available. These problems do not require advanced mathematical techniques, since they can be solved using typical software used by students and practitioners. The method used to solve these problems forces students to understand the trends for the different terms…
Reeves, Charles A.
Uses the chicken problem for sixth grade students to scratch the surface of systems of equations using intuitive approaches. Provides students responses to the problem and suggests similar problems for extensions. (ASK)
Problem, Problem Solving And Critical Thinking
TÜRNÜKLÜ, Elif B.; YEŞİLDERE, Sibel
Critical thinking is an essential skill that all people from various sectors should have and need. Problem solving skill which is one of the main purpose of mathematics teaching can be effective in developing critical thinking. The purpose of this study is to emphasize the importance of problem solving in developing critical thinking skills and to expose critical thinking to the pre-service primary mathematics teachers. Aiming these, some mathematical critical thinking problems are prepa...
Problem solving III: factors influencing classroom problem
Directory of Open Access Journals (Sweden)
Sayonara Salvador Cabral da Costa
Full Text Available This paper presents a review of the literature in the area of problem solving, particularly in physics, focusing only on factors that influence classroom problem solving. Fifty-seven papers have been analyzed in terms of theoretical basis, investigated factors/methodology and findings/relevant factors, which were organized in a table that served as support for a synthesis made by the authors. It is the third of a four-paper series reviewing different aspects of the problem solving subject.
Differential equations problem solver
Arterburn, David R
REA's Problem Solvers is a series of useful, practical, and informative study guides. Each title in the series is complete step-by-step solution guide. The Differential Equations Problem Solver enables students to solve difficult problems by showing them step-by-step solutions to Differential Equations problems. The Problem Solvers cover material ranging from the elementary to the advanced and make excellent review books and textbook companions. They're perfect for undergraduate and graduate studies.The Differential Equations Problem Solver is the perfect resource for any class, any exam, and
... affect desire and function. Psychological causes may include work-related stress and anxiety. They may also include depression or concerns about marriage or relationship problems. For some women, the problem results from past sexual trauma. Occasional ...
... Disease, and Other Dental Problems Diabetic Eye Disease Diabetes and Foot Problems How can diabetes affect my feet? Too much glucose, also called ... you have any of these signs. How can diabetes change the shape of my feet? Nerve damage ...
... Increases in Problem Drinking Join the Fight Against Superbugs Featured Website: Genetic and Rare Diseases Information Center ... Increases in Problem Drinking Join the Fight Against Superbugs Featured Website: Genetic and Rare Diseases Information Center ...
Challenging problems in algebra
Posamentier, Alfred S
Over 300 unusual problems, ranging from easy to difficult, involving equations and inequalities, Diophantine equations, number theory, quadratic equations, logarithms, more. Detailed solutions, as well as brief answers, for all problems are provided.
Karrison, Joan; Carroll, Margaret Kelly
Students with language and learning disabilities may have difficulty solving mathematics word problems. Use of a sequential checklist, identifying clues and keywords, and illustrating a problem can all help the student identify and implement the correct computational process. (DB)
Every pregnancy has some risk of problems. The causes can be conditions you already have or conditions you develop. ... pregnant with more than one baby, previous problem pregnancies, or being over age 35. They can affect ...
Algorithmic Problem Complexity
Burgin, Mark
People solve different problems and know that some of them are simple, some are complex and some insoluble. The main goal of this work is to develop a mathematical theory of algorithmic complexity for problems. This theory is aimed at determination of computer abilities in solving different problems and estimation of resources that computers need to do this. Here we build the part of this theory related to static measures of algorithms. At first, we consider problems for finite words and stud...
Children with behavorial problem
Cerar, Kristina
Behavioral problems are becoming more and more common phenomena in children education. When behavioral problems occur it is very important to have the appropriate approach that mitigates or completely removes them. The key to this is to know as much as possible about children development and behavioral problems. The theoretical part contains the features of a child's development and then I focused on behavioral problems and the causes that bring to such results. I described methods to remove...
Frensch, Peter; Funke, Joachim
Human thinking, and in particular, the human ability to solve complex, real-life problems contributes more than any other human ability to the development of human culture and the growth and development of human life on earth. However, the human ability to solve complex problems is still not well understood, partly because it has for a long time been largely ignored by traditional problem-solving research in the field of psychology. In this article, we present a definition of complex problem ...
Classifying IS Project Problems
DEFF Research Database (Denmark)
Munk-Madsen, Andreas
The literature contains many lists of IS project problems, often in the form of risk factors. The problems sometimes appear unordered and overlapping, which reduces their usefulness to practitioners as well as theoreticians. This paper proposes a list of criteria for formulating project problems...
Optimal obstacle control problem
Institute of Scientific and Technical Information of China (English)
ZHU Li; LI Xiu-hua; GUO Xing-ming
In the paper we discuss some properties of the state operators of the optimal obstacle control problem for elliptic variational inequality. Existence, uniqueness and regularity of the optimal control problem are established. In addition, the approximation of the optimal obstacle problem is also studied.
Mathematics as Problem Solving.
Soifer, Alexander
This book contains about 200 problems. It is suggested that it be used by students, teachers or anyone interested in exploring mathematics. In addition to a general discussion on problem solving, there are problems concerned with number theory, algebra, geometry, and combinatorics. (PK)
Baras, John
The algebraic path problem is a generalization of the shortest path problem in graphs. Various instances of this abstract problem have appeared in the literature, and similar solutions have been independently discovered and rediscovered. The repeated appearance of a problem is evidence of its relevance. This book aims to help current and future researchers add this powerful tool to their arsenal, so that they can easily identify and use it in their own work. Path problems in networks can be conceptually divided into two parts: A distillation of the extensive theory behind the algebraic path pr
Pelleau, Marie; Truchet, Charlotte
This paper presents a new method and a constraint-based objective function to solve two problems related to the design of optical telecommunication networks, namely the Synchronous Optical Network Ring Assignment Problem (SRAP) and the Intra-ring Synchronous Optical Network Design Problem (IDP). These network topology problems can be represented as a graph partitioning with capacity constraints as shown in previous works. We present here a new objective function and a new local search algorithm to solve these problems. Experiments conducted in Comet allow us to compare our method to previous ones and show that we obtain better results.
Semidefinite linear complementarity problems
International Nuclear Information System (INIS)
Semidefinite linear complementarity problems arise by discretization of variational inequalities describing e.g. elastic contact problems, free boundary value problems etc. In the present paper linear complementarity problems are introduced and the theory as well as the numerical treatment of them are described. In the special case of semidefinite linear complementarity problems a numerical method is presented which combines the advantages of elimination and iteration methods without suffering from their drawbacks. This new method has very attractive properties since it has a high degree of invariance with respect to the representation of the set of all feasible solutions of a linear complementarity problem by linear inequalities. By means of some practical applications the properties of the new method are demonstrated. (orig.)
Hidden Symmetry Subgroup Problems
Decker, Thomas; Santha, Miklos; Wocjan, Pawel
We advocate a new approach of addressing hidden structure problems and finding efficient quantum algorithms. We introduce and investigate the Hidden Symmetry Subgroup Problem (HSSP), which is a generalization of the well-studied Hidden Subgroup Problem (HSP). Given a group acting on a set and an oracle whose level sets define a partition of the set, the task is to recover the subgroup of symmetries of this partition inside the group. The HSSP provides a unifying framework that, besides the HSP, encompasses a wide range of algebraic oracle problems, including quadratic hidden polynomial problems. While the HSSP can have provably exponential quantum query complexity, we obtain efficient quantum algorithms for various interesting cases. To achieve this, we present a general method for reducing the HSSP to the HSP, which works efficiently in several cases related to symmetries of polynomials. The HSSP therefore connects in a rather surprising way certain hidden polynomial problems with the HSP. Using this connect...
Creativity for Problem Solvers
DEFF Research Database (Denmark)
Vidal, Rene Victor Valqui
This paper presents some modern and interdisciplinary concepts about creativity and creative processes specially related to problem solving. Central publications related to the theme are briefly reviewed. Creative tools and approaches suitable to support problem solving are also presented. Finally......, the paper outlines the author's experiences using creative tools and approaches to: Facilitation of problem solving processes, strategy development in organisations, design of optimisation systems for large scale and complex logistic systems, and creative design of software optimisation for complex non...
Laughlin, Patrick R
Experimental research by social and cognitive psychologists has established that cooperative groups solve a wide range of problems better than individuals. Cooperative problem solving groups of scientific researchers, auditors, financial analysts, air crash investigators, and forensic art experts are increasingly important in our complex and interdependent society. This comprehensive textbook--the first of its kind in decades--presents important theories and experimental research about group problem solving. The book focuses on tasks that have demonstrably correct solutions within mathematical
The Gamification Design Problem
Meder, Michael; Jain, Brijnesh-Johannes
Under the assumptions that (i) gamification consists of various types of users that experience game design elements differently; and (ii) gamification is deployed in order to achieve some goal in the broadest sense, we pose the gamification problem as that of assigning each user a game design element that maximizes their expected contribution in order to achieve that goal. We show that this problem reduces to a statistical learning problem and suggest matrix factorization as one solution when...
DEFF Research Database (Denmark)
Foss, Kirsten; Foss, Nicolai Juul
as a general approach to problem solving. We apply these Simonian ideas to organisational issues, specifically new organisational forms. Specifically, Simonian ideas allow us to develop a morphology of new organisational forms and to point to some design problems that characterise these forms.......Two of Herbert Simon's best-known papers are 'The Architecture of Complexity' and 'The Structure of Ill-Structured Problems.' We discuss the neglected links between these two papers, highlighting the role of decomposition in the context of problems on which constraints have been imposed...
Singh, Devraj
Numerical Problems in Physics, Volume 1 is intended to serve the need of the students pursuing graduate and post graduate courses in universities with Physics and Materials Science as subject including those appearing in engineering, medical, and civil services entrance examinations. KEY FEATURES: * 29 chapters on Optics, Wave & Oscillations, Electromagnetic Field Theory, Solid State Physics & Modern Physics * 540 solved numerical problems of various universities and ompetitive examinations * 523 multiple choice questions for quick and clear understanding of subject matter * 567 unsolved numerical problems for grasping concepts of the various topic in Physics * 49 Figures for understanding problems and concept
Problems in baryon spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Capstick, S. [Florida State Univ., Tallahassee, FL (United States)
Current issues and problems in the physics of ground- and excited-state baryons are considered, and are classified into those which should be resolved by CEBAF in its present form, and those which may require CEBAF to undergo an energy upgrade to 8 GeV or more. Recent theoretical developments designed to address these problems are outlined.
DEFF Research Database (Denmark)
Ovesen, Nis
Problem-based learning (PBL) is becoming increasingly popular in design educations, but how is it taught and practiced? This paper presents a case study of a three-day workshop that has the purpose of introducing PBL to design students. A theoretical background on PBL and problems in design is es...
The generalized Tailor Problem
Roerdink, J.B.T.M.; Maragos, P; Schafer, RW; Butt, MA
The so-called 'Tailor Problem' concerns putting a number of sets within another set by translation, such that the translated sets do not overlap. In this paper we consider a generalization of this problem in which also rotations of the sets are allowed.
Gladwell, Graham ML
The papers in this volume present an overview of the general aspects and practical applications of dynamic inverse methods, through the interaction of several topics, ranging from classical and advanced inverse problems in vibration, isospectral systems, dynamic methods for structural identification, active vibration control and damage detection, imaging shear stiffness in biological tissues, wave propagation, to computational and experimental aspects relevant for engineering problems.
JS Armstrong
Graffiti is regarded by many as a blight on our cities because it contributes to visual pollution. City governments spend vast sums in an effort to clean the ubiquitous graffiti from urban walls. I suggest that the "cleansing strategy" is an expensive, ineffective way of dealing with the problem; well-known management techniques can solve the problem more efficiently.
Allen, Deborah E.; Donham, Richard S.; Bernhardt, Stephen A.
In problem-based learning (PBL), students working in collaborative groups learn by resolving complex, realistic problems under the guidance of faculty. There is some evidence of PBL effectiveness in medical school settings where it began, and there are numerous accounts of PBL implementation in various undergraduate contexts, replete with…
... problems that can lead to dislocation of the hip bones. This is also called dysplasia (say: "diss-play-see-uh"). This means that ... problems later in life? Source Screening for Developmental Dysplasia of the Hip by LM French, M.D., and FR Dietz, ...
Wicked Problems: Inescapable Wickedity
Jordan, Michelle E.; Kleinsasser, Robert C.; Roe, Mary F.
The article explores the concept of wicked problems and proposes a reinvigorated application of this concept for wider educational use. This recommendation stems from the contributions of a number of scholars who frame some of the most contentious and recalcitrant educational issues as wicked problems. The present authors build upon these previous…
Current Social Problem Novels.
Kenney, Donald J.
This review of social problem novels for young adults opens with a brief background of the genre, then lists the dominant themes of social problem fiction and nonfiction novels that have been published in the last two years, such as alcoholism, alienation, death, growing up and self-awarness, drugs, and divorce. Other themes mentioned are…
Medical problems affecting musicians.
Potter, P J; Jones, I C
The physical demands of performing on musical instruments can cause pain, sensory loss, and lack of coordination. Five cases illustrate common problems. Knowledge of the interaction between the technique of playing the instrument and the particular musician can help physicians diagnose and resolve problems.
Meng, G.; Heragu, S.S.; Zijm, H.
This paper addresses the reconfigurable layout problem, which differs from traditional, robust and dynamic layout problems mainly in two aspects: first, it assumes that production data are available only for the current and upcoming production period. Second, it considers queuing performance measure
Routing and scheduling problems
DEFF Research Database (Denmark)
Reinhardt, Line Blander
of a connection between two locations. This could be an urban bus schedule where busses are routed and this routing creates a bus schedule which the passengers between locations use. In this thesis various routing and scheduling problems will be presented. The topics covered will be routing from an origin...... set cost making the cost of the individual vehicle routes inter-dependant. Depending on the problem type, the size of the problems and time available for solving, different solution methods can be applicable. In this thesis both heuristic methods and several exact methods are investigated depending...... on the problems needed to be solved. The solution methods applied to the problems cover dynamic programming for multi constrained shortest paths, Branch-and-cut for liner shipping, Simulated annealing for transporting assisted passengers in airports, branch-cut-and-price for vehicle routing with time windows...
Singh, Chandralekha
One finding of cognitive research is that people do not automatically acquire usable knowledge by spending lots of time on task. Because students' knowledge hierarchy is more fragmented, "knowledge chunks" are smaller than those of experts. The limited capacity of short term memory makes the cognitive load high during problem solving tasks, leaving few cognitive resources available for metacognition. The abstract nature of the laws of physics and the chain of reasoning required to draw meaningful inferences makes these issues critical. In order to help students, it is crucial to consider the difficulty of a problem from the perspective of students. We are developing and evaluating interactive problem-solving tutorials to help students in the introductory physics courses learn effective problem-solving strategies while solidifying physics concepts. The self-paced tutorials can provide guidance and support for a variety of problem solving techniques, and opportunity for knowledge and skill acquisition.
The Interaction Programming Problem
Institute of Scientific and Technical Information of China (English)
LI Rong-sheng; CHENG Ying
Based upon the research to the economic equilibrium problems, we present a kind of new mathematical programming problem-interaction programming problem (abbreviated by IPP). The IPP is composed of two or multiple parametric programming problems which is interrelated with each other. The IPP reflects the equality and mutual benefit relationship between two (or among multiple) economic planners in an economic system. In essence, the IPP is similar to the generalized Nash equilibria (GNE) game which has been given several names in the literature: social equilibria games, pseudo-Nash equilibria games, and equilibrium programming problems. In this paper, we establish the mathematical model and some basic concepts to the IPP. We investigate the structure and the properties of the IPP. We also give a necessary and sufficient conditions for the existence of the equilibrium points to a kind of linear IPP.
Problems in equilibrium theory
Aliprantis, Charalambos D
In studying General Equilibrium Theory the student must master first the theory and then apply it to solve problems. At the graduate level there is no book devoted exclusively to teaching problem solving. This book teaches for the first time the basic methods of proof and problem solving in General Equilibrium Theory. The problems cover the entire spectrum of difficulty; some are routine, some require a good grasp of the material involved, and some are exceptionally challenging. The book presents complete solutions to two hundred problems. In searching for the basic required techniques, the student will find a wealth of new material incorporated into the solutions. The student is challenged to produce solutions which are different from the ones presented in the book.
The Guderley problem revisited
Energy Technology Data Exchange (ETDEWEB)
Ramsey, Scott D [Los Alamos National Laboratory; Kamm, James R [Los Alamos National Laboratory; Bolstad, John H [NON LANL
The self-similar converging-diverging shock wave problem introduced by Guderley in 1942 has been the source of numerous investigations since its publication. In this paper, we review the simplifications and group invariance properties that lead to a self-similar formulation of this problem from the compressible flow equations for a polytropic gas. The complete solution to the self-similar problem reduces to two coupled nonlinear eigenvalue problems: the eigenvalue of the first is the so-called similarity exponent for the converging flow, and that of the second is a trajectory multiplier for the diverging regime. We provide a clear exposition concerning the reflected shock configuration. Additionally, we introduce a new approximation for the similarity exponent, which we compare with other estimates and numerically computed values. Lastly, we use the Guderley problem as the basis of a quantitative verification analysis of a cell-centered, finite volume, Eulerian compressible flow algorithm.
Dürr, Christoph; Spieksma, Frits C R; Nobibon, Fabrice Talla; Woeginger, Gerhard J
For a given set of intervals on the real line, we consider the problem of ordering the intervals with the goal of minimizing an objective function that depends on the exposed interval pieces (that is, the pieces that are not covered by earlier intervals in the ordering). This problem is motivated by an application in molecular biology that concerns the determination of the structure of the backbone of a protein. We present polynomial-time algorithms for several natural special cases of the problem that cover the situation where the interval boundaries are agreeably ordered and the situation where the interval set is laminar. Also the bottleneck variant of the problem is shown to be solvable in polynomial time. Finally we prove that the general problem is NP-hard, and that the existence of a constant-factor-approximation algorithm is unlikely.
DEFF Research Database (Denmark)
Tietjen, Anne; Jørgensen, Gertrud
In a time of increasing globalisation and urbanisation, shrinking peripheral rural areas have become a truly wicked planning problem in many European countries. Although a problem can be easily perceived and measured by various indicators, the precise definition of the problem is problematic. Based...... on the case of a Danish planning process which was carried out in collaboration with a charitable trust, this paper discusses an emerging strategic planning approach at the municipal level. We use the concept of wicked problems, strategic planning theory and Actor-Network-Theory to study a collaborative...... projects played a major role in this process. First, they acted as a vehicle that assembled planners, politicians and stakeholders to work towards strategic visions across multiple scales. Second and consequently, they stimulated considerable second and third order effects in the form of shared problem...
Trahtman, A N
The synchronizing word of deterministic automaton is a word in the alphabet of colors (considered as letters) of its edges that maps the automaton to a single state. A coloring of edges of a directed graph is synchronizing if the coloring turns the graph into deterministic finite automaton possessing a synchronizing word. The road coloring problem is a problem of synchronizing coloring of directed finite strongly connected graph with constant outdegree of all its vertices if the greatest common divisor of lengths of all its cycles is one. The problem was posed by Adler, Goodwyn and Weiss over 30 years ago and evoked a noticeable interest among the specialists in theory of graphs, deterministic automata and symbolic dynamics. The problem is described even in "Vikipedia" - the popular Internet Encyclopedia. The positive solution of the road coloring problem is presented.
Problems of energy supply. Probleme der Energieversorgung
Energy Technology Data Exchange (ETDEWEB)
Frank, W.
Political education is to enable judgement of present-day questions. This requires knowledge of the essential facts in the field of energy supply. The brochure on hand is meant to make it easier for the reader to put forward his own arguments. The reader is to see that it is due to the many motives determining energy policy which aggravate an understanding about ways of solving problems of energy supply. This brochure is designed to enhance political education by giving a survey of tasks in energy policy to be solved on an international level and in Austria.
Generalized emissivity inverse problem.
Ming, DengMing; Wen, Tao; Dai, XianXi; Dai, JiXin; Evenson, William E
Inverse problems have recently drawn considerable attention from the physics community due to of potential widespread applications [K. Chadan and P. C. Sabatier, Inverse Problems in Quantum Scattering Theory, 2nd ed. (Springer Verlag, Berlin, 1989)]. An inverse emissivity problem that determines the emissivity g(nu) from measurements of only the total radiated power J(T) has recently been studied [Tao Wen, DengMing Ming, Xianxi Dai, Jixin Dai, and William E. Evenson, Phys. Rev. E 63, 045601(R) (2001)]. In this paper, a new type of generalized emissivity and transmissivity inverse (GETI) problem is proposed. The present problem differs from our previous work on inverse problems by allowing the unknown (emissivity) function g(nu) to be temperature dependent as well as frequency dependent. Based on published experimental information, we have developed an exact solution formula for this GETI problem. A universal function set suggested for numerical calculation is shown to be robust, making this inversion method practical and convenient for realistic calculations.
DEFF Research Database (Denmark)
Reng, Lars; Schoenau-Fog, Henrik
At Aalborg University's department of Medialogy, we are utilizing the Problem Based Learning method to encourage students to solve game design problems by pushing the boundaries and designing innovative games. This paper is concerned with describing this method, how students employ it in various ...... projects and how they learn to analyse, design, and develop for innovation by using it. We will present various cases to exemplify the approach and focus on how the method engages students and aspires for innovation in digital entertainment and games.......At Aalborg University's department of Medialogy, we are utilizing the Problem Based Learning method to encourage students to solve game design problems by pushing the boundaries and designing innovative games. This paper is concerned with describing this method, how students employ it in various...
Eperson, D. B.
Presents six mathematical problems (with answers) which focus on: (1) chess moves; (2) patterned numbers; (3) quadratics with rational roots; (4) number puzzles; (5) Euclidean geometry; and (6) Carrollian word puzzles. (JN)
... Health Information Basics for You and Your Family Sports Injuries, Handout on Health Health Information Knee Problems Find ... for a long time. This sometimes occurs in sports training. Treatment for tendon injuries and disorders includes: Rest Ice Elevation Medicines such ...
Creativity and Problem Solving
DEFF Research Database (Denmark)
Vidal, Rene Victor Valqui
This paper presents some modern and interdisciplinary concepts about creativity and creative processes of special relevance for Operational Research workers. Central publications in the area Creativity-Operational Research are shortly reviewed. Some creative tools and the Creative Problem Solving...
Problems sleeping during pregnancy
... page: //medlineplus.gov/ency/patientinstructions/000559.htm Problems sleeping during pregnancy To use the sharing features on ... time sleeping well. Why is it hard to sleep during pregnancy? Your baby is growing bigger, which ...
Challenging problems in geometry
Posamentier, Alfred S
Collection of nearly 200 unusual problems dealing with congruence and parallelism, the Pythagorean theorem, circles, area relationships, Ptolemy and the cyclic quadrilateral, collinearity and concurrency and more. Arranged in order of difficulty. Detailed solutions.
Nash, Jr, John Forbes
The goal in putting together this unique compilation was to present the current status of the solutions to some of the most essential open problems in pure and applied mathematics. Emphasis is also given to problems in interdisciplinary research for which mathematics plays a key role. This volume comprises highly selected contributions by some of the most eminent mathematicians in the international mathematical community on longstanding problems in very active domains of mathematical research. A joint preface by the two volume editors is followed by a personal farewell to John F. Nash, Jr. written by Michael Th. Rassias. An introduction by Mikhail Gromov highlights some of Nash's legendary mathematical achievements. The treatment in this book includes open problems in the following fields: algebraic geometry, number theory, analysis, discrete mathematics, PDEs, differential geometry, topology, K-theory, game theory, fluid mechanics, dynamical systems and ergodic theory, cryptography, theoretical computer sc...
The Congruence Subgroup Problem
Indian Academy of Sciences (India)
M S Raghunathan
This is a short survey of the progress on the congruence subgroup problem since the sixties when the first major results on the integral unimodular groups appeared. It is aimed at the non-specialists and avoids technical details.
... too high. Over time, this can damage your eyes. The most common problem is diabetic retinopathy. It ... light-sensitive tissue at the back of your eye. You need a healthy retina to see clearly. ...
... and rashes clinical tools newsletter | contact Share | Common Foot Problems A A A Trauma, infection, skin disease, ... the sole of the front part of the foot and on the toes. Foot infections include warts; ...
J Gordon Millichap
The prevalence of sleep problems and their associations with quality of life (QOL), school attendance, and family impacts in children with ADHD were determined in a study at Royal Children's Hospital, University of Melbourne, Australia.
Rubinstein, J Hyam
This is a personal view of some problems on minimal surfaces, Ricci flow, polyhedral geometric structures, Haken 4-manifolds, contact structures and Heegaard splittings, singular incompressible surfaces after the Hamilton-Perelman revolution.
Institute of Scientific and Technical Information of China (English)
There have considerable number of design philosophies and design methods in this world,but today I'd like to intorduce a new design problem solving system which comes from Chinese traditonal religion Dao.
... nonsurgical ways to obtain symptom relief? • What are Kegel exercises? • Can surgery correct pelvic support problems? • Glossary ... your overall health and possibly your prolapse symptoms. • Kegel exercises—These exercises strengthen the muscles that surround ...
Rousseau, Madeleine; Ter Haar, D
This collection of problems and accompanying solutions provide the reader with a full introduction to physical optics. The subject coverage is fairly traditional, with chapters on interference and diffraction, and there is a general emphasis on spectroscopy.
Scheper, W A; Lobbezoo, F; Eijkman, M A J
Divers can have several oral problems. Firstly, problems caused by pressure changes. These are barodontalgia and odontocrexis. Barodontalgia is toothache by barotrauma. Odontocrexis is restorations coming lose or breaking or tooth fractures by expansion of air beneath restorations. Other problems can occur by cements used to fix casted restorations, by inflammations in the orofacial region, and by not yet fully healed oral wounds. Secondly, there are problems related to the diver's mouthpiece. To keep the mouthpiece in place, the mandible has to be forced in a forward position. Holding this position often and for long periods of time, may develop or aggravate temporomandibular dysfunction. Insufficient fit of the mouthpiece may induce oral mucosal lesions. Therefore, it is recommended to produce individual diver mouthpieces. It is also recommended to produce individual diver mouthpieces for complete dentures wearing divers and for divers with fixed orthodontic appliances.
Directory of Open Access Journals (Sweden)
J Gordon Millichap
Full Text Available The prevalence of sleep problems and their associations with quality of life (QOL, school attendance, and family impacts in children with ADHD were determined in a study at Royal Children's Hospital, University of Melbourne, Australia.
Helfgott, Harald Andrés
The ternary Goldbach conjecture, or three-primes problem, states that every odd number $n$ greater than $5$ can be written as the sum of three primes. The conjecture, posed in 1742, remained unsolved until now, in spite of great progress in the twentieth century. In 2013 -- following a line of research pioneered and developed by Hardy, Littlewood and Vinogradov, among others -- the author proved the conjecture. In this, as in many other additive problems, what is at issue is really the proper...
Trahtman, A. N.
The synchronizing word of deterministic automaton is a word in the alphabet of colors (considered as letters) of its edges that maps the automaton to a single state. A coloring of edges of a directed graph is synchronizing if the coloring turns the graph into deterministic finite automaton possessing a synchronizing word. The road coloring problem is a problem of synchronizing coloring of directed finite strongly connected graph with constant outdegree of all its vertices if the greatest comm...
Schröer, H.
In basketball there is the problem of hitting a basket at a determined distance and a determined height. The quantities that can be changed during the inclined throw are the initial velocity and the angle of throw. At first we neglect the air resistance. Then we treat the same problem in a medium (liquid, gas) with constant density. We obtain two differential equations. Then we view special cases of the retarding force. There is an english and a german edition.
Hubble, Douglas
Adolescence is a period of active growth and development-physical, sexual, social and emotional. There are wide normal variations between the time of onset and the attainment of full maturity. Many adolescents present few if any problems during this potentially turbulent period, and make the necessary adjustments without undue stress to themselves, their family or their friends. Problems in growth and hormonal balance, presenting as short and tall teenagers, menstrual irregularities, obesity ...
Hwang, FK; Winter, P
The Steiner problem asks for a shortest network which spans a given set of points. Minimum spanning networks have been well-studied when all connections are required to be between the given points. The novelty of the Steiner tree problem is that new auxiliary points can be introduced between the original points so that a spanning network of all the points will be shorter than otherwise possible. These new points are called Steiner points - locating them has proved problematic and research has diverged along many different avenues. This volume is devoted to the assimilation of the rich field of intriguing analyses and the consolidation of the fragments. A section has been given to each of the three major areas of interest which have emerged. The first concerns the Euclidean Steiner Problem, historically the original Steiner tree problem proposed by Jarník and Kössler in 1934. The second deals with the Steiner Problem in Networks, which was propounded independently by Hakimi and Levin and has enjoyed the most...
Steiner Forest Orientation Problems
Cygan, Marek; Nutov, Zeev
We consider connectivity problems with orientation constraints. Given a directed graph $D$ and a collection of ordered node pairs $P$ let $P[D]={(u,v) \\in P: D contains a uv-paths}$. In the Steiner Forest Orientation problem we are given an undirected graph $G=(V,E)$ with edge-costs and a set $P \\subseteq V \\times V$ of ordered node pairs. The goal is to find a minimum-cost subgraph $H$ of $G$ and an orientation $D$ of $H$ such that $P[D]=P$. We give a 4-approximation algorithm for this problem. In the Maximum Pairs Orientation problem we are given a graph $G$ and a multi-collection of ordered node pairs $P$ on $V$. The goal is to find an orientation $D$ of $G$ such that $|P[D]|$ is maximum. Generalizing the result of Arkin and Hassin for $|P|=2$, we will show that for a mixed graph $G$ (that may have both directed an undirected edges), one can decide in $n^{O(|P|)}$ time whether $G$ has an orientation $D$ with $P[D]=P$ (for undirected graphs this problem admits a polynomial time algorithm for any $P$, but it...
Colored Traveling Salesman Problem.
Li, Jun; Zhou, MengChu; Sun, Qirui; Dai, Xianzhong; Yu, Xiaolong
The multiple traveling salesman problem (MTSP) is an important combinatorial optimization problem. It has been widely and successfully applied to the practical cases in which multiple traveling individuals (salesmen) share the common workspace (city set). However, it cannot represent some application problems where multiple traveling individuals not only have their own exclusive tasks but also share a group of tasks with each other. This work proposes a new MTSP called colored traveling salesman problem (CTSP) for handling such cases. Two types of city groups are defined, i.e., each group of exclusive cities of a single color for a salesman to visit and a group of shared cities of multiple colors allowing all salesmen to visit. Evidences show that CTSP is NP-hard and a multidepot MTSP and multiple single traveling salesman problems are its special cases. We present a genetic algorithm (GA) with dual-chromosome coding for CTSP and analyze the corresponding solution space. Then, GA is improved by incorporating greedy, hill-climbing (HC), and simulated annealing (SA) operations to achieve better performance. By experiments, the limitation of the exact solution method is revealed and the performance of the presented GAs is compared. The results suggest that SAGA can achieve the best quality of solutions and HCGA should be the choice making good tradeoff between the solution quality and computing time.
Bicriteria network design problems
Energy Technology Data Exchange (ETDEWEB)
Marathe, M.V. [Los Alamos National Lab., NM (United States); Ravi, R. [Princeton Univ., NJ (United States); Sundaram, R. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Ravi, S.S.; Rosenkrantz, D.J.; Hunt, H.B. III [State Univ. of New York, Albany, NY (United States). Dept. of Computer Science
The authors study a general class of bicriteria network design problems. A generic problem in this class is as follows: Given an undirected graph and two minimization objectives (under different cost functions), with a budget specified on the first, find a subgraph from a given subgraph class that minimizes the second objective subject to the budget on the first. They consider three different criteria -- the total edge cost, the diameter and the maximum degree of the network. Here, they present the first polynomial-time approximation algorithms for a large class of bicriteria network design problems for the above mentioned criteria. The following general types of results are presented. First, they develop a framework for bicriteria problems and their approximations. Second, when the two criteria are the same they present a black box parametric search technique. This black box takes in as input an (approximation) algorithm for the criterion situation and generates an approximation algorithm for the bicriteria case with only a constant factor loss in the performance guarantee. Third, when the two criteria are the diameter and the total edge costs they use a cluster based approach to devise approximation algorithms. The solutions violate both the criteria by a logarithmic factor. Finally, for the class of treewidth-bounded graphs, they provide pseudopolynomial-time algorithms for a number of bicriteria problems using dynamic programming. The authors show how these pseudopolynomial-time algorithms can be converted to fully polynomial-time approximation schemes using a scaling technique.
Sperling, J
In 1927 the great physicist Paul A. M. Dirac failed to provide a consistent quantum description of the phase of a radiation field. Only one year later, he developed the famous Dirac theory of the electron, which led to the anti-particle -- the positron. We show that the reason for Dirac's failure with the phase problem bears a striking resemblance to his ingenious insight into the nature of the electron. For a correct quantum description of the phase of a radiation field it is necessary to take the polarisation into account. Similarly to the introduction of the anti-particle of the electron, the inclusion of the second polarisation resolves the inconsistency of the quantum phase problem. This also leads to new insight into the quantum measurement problem of time.
Computational problems in engineering
Mladenov, Valeri
This book provides readers with modern computational techniques for solving variety of problems from electrical, mechanical, civil and chemical engineering. Mathematical methods are presented in a unified manner, so they can be applied consistently to problems in applied electromagnetics, strength of materials, fluid mechanics, heat and mass transfer, environmental engineering, biomedical engineering, signal processing, automatic control and more. • Features contributions from distinguished researchers on significant aspects of current numerical methods and computational mathematics; • Presents actual results and innovative methods that provide numerical solutions, while minimizing computing times; • Includes new and advanced methods and modern variations of known techniques that can solve difficult scientific problems efficiently.
DEFF Research Database (Denmark)
de Graaff, Erik; Guerra, Aida
Problem-Based Learning (PBL) is an innovative method to organize the learning process in such a way that the students actively engage in finding answers by themselves. During the past 40 years PBL has evolved and diversified resulting in a multitude in variations in models and practices. However...... model and in general problem based and project based learning. We apply the principle of teach as you preach. The poster aims to outline the visitors' workshop programme showing the results of some recent evaluations......., the key principles remain the same everywhere. Graaff & Kolmos (2003) identify the main PBL principles as follows: 1. Problem orientation 2. Project organization through teams or group work 3. Participant-directed 4. Experiental learning 5. Activity-based learning 6. Interdisciplinary learning and 7...
Chou, Kai-Seng
Although research in curve shortening flow has been very active for nearly 20 years, the results of those efforts have remained scattered throughout the literature. For the first time, The Curve Shortening Problem collects and illuminates those results in a comprehensive, rigorous, and self-contained account of the fundamental results.The authors present a complete treatment of the Gage-Hamilton theorem, a clear, detailed exposition of Grayson''s convexity theorem, a systematic discussion of invariant solutions, applications to the existence of simple closed geodesics on a surface, and a new, almost convexity theorem for the generalized curve shortening problem.Many questions regarding curve shortening remain outstanding. With its careful exposition and complete guide to the literature, The Curve Shortening Problem provides not only an outstanding starting point for graduate students and new investigations, but a superb reference that presents intriguing new results for those already active in the field.
Revisiting the Lambert's Problem
Izzo, Dario
The orbital boundary value problem, also known as Lambert Problem, is revisited. Building upon Lancaster and Blanchard approach, new relations are revealed and a new variable representing all problem classes, under L-similarity, is used to express the time of flight equation. In the new variable, the time of flight curves have two oblique asymptotes and they mostly appear to be conveniently approximated by piecewise continuous lines. We use and invert such a simple approximation to provide an efficient initial guess to an Householder iterative method that is then able to converge, for the single revoltuion case, in only two iterations. The resulting algorithm is compared to Gooding's procedure revealing to be numerically as accurate, while having a smaller computational complexity.
Problems over Information Systems
Chikalov, Igor
The problems of estimation of the minimum average time complexity of decision trees and design of efficient algorithms are complex in general case. The upper bounds described in Chap. 2.4.3 can not be applied directly due to large computational complexity of the parameter M(z). Under reasonable assumptions about the relation of P and NP, there are no polynomial time algorithms with good approximation ratio [12, 32]. One of the possible solutions is to consider particular classes of problems and improve the existing results using characteristics of the considered classes. © Springer-Verlag Berlin Heidelberg 2011.
Electric circuits problem solver
REA, Editors of
Each Problem Solver is an insightful and essential study and solution guide chock-full of clear, concise problem-solving gems. All your questions can be found in one convenient source from one of the most trusted names in reference solution guides. More useful, more practical, and more informative, these study aids are the best review books and textbook companions available. Nothing remotely as comprehensive or as helpful exists in their subject anywhere. Perfect for undergraduate and graduate studies.Here in this highly useful reference is the finest overview of electric circuits currently av
Advanced calculus problem solver
REA, Editors of
Each Problem Solver is an insightful and essential study and solution guide chock-full of clear, concise problem-solving gems. All your questions can be found in one convenient source from one of the most trusted names in reference solution guides. More useful, more practical, and more informative, these study aids are the best review books and textbook companions available. Nothing remotely as comprehensive or as helpful exists in their subject anywhere. Perfect for undergraduate and graduate studies.Here in this highly useful reference is the finest overview of advanced calculus currently av
Calculus problems and solutions
Ginzburg, A
Ideal for self-instruction as well as for classroom use, this text helps students improve their understanding and problem-solving skills in analysis, analytic geometry, and higher algebra. More than 1,200 problems appear in the text, with concise explanations of the basic notions and theorems to be used in their solution. Many are followed by complete answers; solutions for the others appear at the end of the book. Topics include sequences, functions of a single variable, limit of a function, differential calculus for functions of a single variable, fundamental theorems and applications of dif
Institute of Scientific and Technical Information of China (English)
The pricing of electricity trasmission requires determining how much use each generator is making of a transmission line and what is each generator's contribution to the system losses. Such problems cannot be solved by only using Kirchoff's laws. This paper proposes two current decomposition axioms based on which the theories and models are established for the current trace problem. To create an efficient algorithm the graph theory is employed. It is proved that there is no directed circuit in a directed current distribution graph. According to this theorem a very simple and efficient algorithm based on recursive elimination process is suggested. A simple example is used to explain the algorithm.
Solving Environmental Problems
DEFF Research Database (Denmark)
Grimpe, Christoph; Ørding Olsen, Anders; Sofka, Wolfgang
dispersed. As a result, firms frequently collaborate with international partners. We shed new light on collaborative search strategies led by firms in general and for solving environmental problems in particular. Both topics are largely absent in the extant open innovation literature. Using data from...... the European Seventh Framework Programme for research and technological development, our results indicate that the problem solving potential of a search strategy increases with the diversity of existing knowledge of the partners in a consortium and with the experience of the partners involved. Moreover, we...
Kogan, VI; Gersch, Harold
Written by a pair of distinguished Soviet mathematicians, this compilation presents 160 lucidly expressed problems in nonrelativistic quantum mechanics plus completely worked-out solutions. Some were drawn from the authors' courses at the Moscow Institute of Engineering, but most were prepared especially for this book. A high-level supplement rather than a primary text, it constitutes a masterful complement to advanced undergraduate and graduate texts and courses in quantum mechanics.The mathematics employed in the proofs of the problems-asymptotic expansions of functions, Green's functions, u
Electrical problems committee report
International Nuclear Information System (INIS)
This document is the report of the committee appointed to review the experience of the MFE Program with electrical equipment and to suggest actions to minimize future problems. The committee observed that the electrical problems that have occurred could be traced not to misapplication of project and engineering technical principles, but to lack of application of project and engineering management principles. The report is structured so that the first four sections: Introduction, Findings, Recommendations, and Immediate Recommended Actions, can be used as an executive summary. The discussion section and attachments contain further detail
Matrices in Engineering Problems
Tobias, Marvin
This book is intended as an undergraduate text introducing matrix methods as they relate to engineering problems. It begins with the fundamentals of mathematics of matrices and determinants. Matrix inversion is discussed, with an introduction of the well known reduction methods. Equation sets are viewed as vector transformations, and the conditions of their solvability are explored. Orthogonal matrices are introduced with examples showing application to many problems requiring three dimensional thinking. The angular velocity matrix is shown to emerge from the differentiation of the 3-D orthogo
The Quantum Falsifiability Problem
Dall'Arno, Michele; Brandsen, Sarah; Buscemi, Francesco
A hypothesis about a physical device is falsified as soon as an experiment collects data that is not compatible with it. Here we construct a general framework to study the quantum falsifiability problem, namely, the problem of deciding whether a given input-output probability distribution (i.e., the data) can be obtained from a given candidate quantum channel (i.e., the hypothesis) or not. Our approach is completely device-independent, as the piece of experimental evidence -- the input-output...
Classic Problems of Probability
Gorroochurn, Prakash
"A great book, one that I will certainly add to my personal library."—Paul J. Nahin, Professor Emeritus of Electrical Engineering, University of New Hampshire Classic Problems of Probability presents a lively account of the most intriguing aspects of statistics. The book features a large collection of more than thirty classic probability problems which have been carefully selected for their interesting history, the way they have shaped the field, and their counterintuitive nature. From Cardano's 1564 Games of Chance to Jacob Bernoulli's 1713 Golden Theorem to Parrondo's 1996 Perplexin
Assessing the Quality of Problems in Problem-Based Learning
Sockalingam, Nachamma; Rotgans, Jerome; Schmidt, Henk
This study evaluated the construct validity and reliability of a newly devised 32-item problem quality rating scale intended to measure the quality of problems in problem-based learning. The rating scale measured the following five characteristics of problems: the extent to which the problem (1) leads to learning objectives, (2) is familiar, (3)…
Emmel, Thomas C.; Sligh, Michael M.
Asserts that overpopulation is the most pressing world problem. Topics discussed include population control in primitive societies, population growth and control in modern societies, methods of motivational population control, consequences of no population control, and mass famines during the 1970's in underdeveloped countries. Cities 33…
International Nuclear Information System (INIS)
The risks of accidents and the safety actions concerning the components and the staff protection at Vivitron are analyzed. The risks induced by the utilization of SF6 is mainly asphyxia. The sealing defects on the gas storage devices and gas leaking inside Vivitron are considered. The safety actions and devices are summarized. Radiation protection problems are also discussed
International Nuclear Information System (INIS)
The meeting of the Radiation Energy Spectra Unfolding Workshop organized by the Radiation Shielding Information Center is discussed. The plans of the unfolding code benchmarking effort to establish methods of standardization for both the few channel neutron and many channel gamma-ray and neutron spectroscopy problems are presented
Nelson, Norman N.; Fisch, Forest N.
Discussed are techniques of presentation and solution of the Classical Cake Problem. A frosted cake with a square base is to be cut into n pieces with the volume of cake and frosting the same for each piece. Needed are minimal geometric concepts and the formula for the volume of a prism. (JP)
Naboulsi, R
A review on CP violation in the B and K mesons systems is given, which, we hope may familiarize new Belle members in the basic ingredients of this topic, which is one of the most challenging problems of experimental high energy physics.
... of a lack of health-care providers, an absence of insurance, or transportation problems. The American Academy of Pediatrics believes that all children deserve a "medical home" and supports the implementation of school-based clinics, especially in areas where children do ...
Managing soil remediation problems.
Okx, J P; Hordijk, L; Stein, A
Soil remediation has only a short history but the problem addressed is a significant one. Cost estimates for the clean-up of contaminated sites in the European Union and the United States are in the order of magnitude of 1,400 billion ECU. Such an enormous operation deserves the best management it can get. Reliable cost estimations per contaminated site are an important prerequisite. This paper addresses the problems related to site-wise estimations.When solving soil remediation problems, we have to deal with a large number of scientific disciplines. Too often solutions are presented from the viewpoint of only one discipline. In order to benefit from the combined disciplinary knowledge and experience, we think that it is necessary to describe the interrelations between these disciplines. This can be realized by developing an adequate model of the desired process which enables to consider and evaluate the essential factors as interdependent components of the total system.The resulting model provides a binding paradigm to the contributing disciplines which will result in improved efficiency and effectivity of the decision and the cost estimation process. In the near future, we will release the "Biosparging and Bioventing Expert Support System", an expert support system for problem owners, consultants and authorities dealing with the design and operation of a biosparging and/or a bioventing system.
Environmental Health Problems.
Environmental Health Service (DHEW/PHS), Rockville, MD.
Aimed at a society which is forced to make decisions relative to their total environment, this pamphlet discusses a few of the problems associated with restoring and maintaining an environmental relationship conducive to the health and well-being of man. The topics covered include: air pollution, noise, solid waste, the urban environment, drinking…
... of time in their own world—even for teenagers—but they're often lonely and want to make friends. The problem is, they're not sure how to act in social settings. Between that and their eccentricities, they may become victims of teasing and bullying . Parents of a child with AS, or any ...
... a clinical breast exam done? • What is breast self-awareness? • How is breast self-awareness different from the traditional breast self-exam? •Glossary ... problems includes mammography , clinical breast exams, and breast self-awareness. What is mammography? Mammography is an X-ray ...
The information recovery problem
Baccetti, Valentina; Terno, Daniel R
The problem of rescuing unitary matter evolution on a black hole spacetime remains unresolved. We argue that some prominent cures are more troubling than the disease, demonstrate that their central element --- forming of the event horizon before the evaporation begins --- is not necessarily true, and describe a fully coupled matter-gravity system which is manifestly unitary.
Institute of Scientific and Technical Information of China (English)
刘香情; 钱丹
With the population growing, a lot of problems have come out, Nowadays a lot of tall buildings have been built, but the houses are still very short; A lot of cars and buses have increased, but they are still crowded with people; A lot of schools have been built,
De Bono, Edward
A group of children were presented with several tasks, including the invention of a sleep machine and a machine to weigh elephants. The tasks were chosen to involve the children in coping with problems of a distinct character. A study of the children's drawings and interpretations shows that children's thinking ability is not very different from…
Nervous System Problems and Dementia
... Language: Fact Sheet 505 Nervous System Problems and Dementia WHAT ARE NERVOUS SYSTEM PROBLEMS? WHAT ARE THE ... of AIDS these were all called "HIV-Associated Dementia." However, a broader range of problems is showing ...
How to solve mathematical problems
Wickelgren, Wayne A
Seven problem-solving techniques include inference, classification of action sequences, subgoals, contradiction, working backward, relations between problems, and mathematical representation. Also, problems from mathematics, science, and engineering with complete solutions.
No Problem? No Research, Little Learning ... Big Problem!
Directory of Open Access Journals (Sweden)
Fernando Ornelas Marques
Full Text Available The motivation to carry out this study stemmed from the generalized perception that nowadays youth lacks the skills for the 21st century. Especially the high-level competences like critical thinking, problem solving and autonomy. Several tools can help to improve these competences (e.g. the SCRATCH programming language, but, as researchers and educators, we are mostly concerned with the skill to recognize problems. What if we do not find problems to solve? What if we do not even feel the need to find or solve problems? The problem is to recognize the problem; the next step is to equate the problem; finally we have to feel the need to solve it. No need? No invention. Recognizing a problem is probably the biggest problem of everyday life, because we are permanently faced with problems (many ill-defined problems, which we need to identify, equate and solve.
Scattering problems in elastodynamics
Diatta, Andre; Kadic, Muamer; Wegener, Martin; Guenneau, Sebastien
In electromagnetism, acoustics, and quantum mechanics, scattering problems can routinely be solved numerically by virtue of perfectly matched layers (PMLs) at simulation domain boundaries. Unfortunately, the same has not been possible for general elastodynamic wave problems in continuum mechanics. In this Rapid Communication, we introduce a corresponding scattered-field formulation for the Navier equation. We derive PMLs based on complex-valued coordinate transformations leading to Cosserat elasticity-tensor distributions not obeying the minor symmetries. These layers are shown to work in two dimensions, for all polarizations, and all directions. By adaptative choice of the decay length, the deep subwavelength PMLs can be used all the way to the quasistatic regime. As demanding examples, we study the effectiveness of cylindrical elastodynamic cloaks of the Cosserat type and approximations thereof.
Scattering problems in elastodynamics
Diatta, Andre; Wegener, Martin; Guenneau, Sebastien
In electromagnetism, acoustics, and quantum mechanics, scattering problems can routinely be solved numerically by virtue of perfectly matched layers (PMLs) at simulation domain boundaries. Unfortunately, the same has not been possible for general elastodynamic wave problems in continuum mechanics. In this paper, we introduce a corresponding scattered-field formulation for the Navier equation. We derive PMLs based on complex-valued coordinate transformations leading to Cosserat elasticity-tensor distributions not obeying the minor symmetries. These layers are shown to work in two dimensions, for all polarizations, and all directions. By adaptative choice of the decay length, the deep subwavelength PMLs can be used all the way to the quasi-static regime. As demanding examples, we study the effectiveness of cylindrical elastodynamic cloaks of the Cosserat type and approximations thereof.
Directory of Open Access Journals (Sweden)
Michael Segal
Full Text Available Abstract: Ad-hoc networks of sensor nodes are in general semi-permanently deployed. However, the topology of such networks continuously changes over time, due to the power of some sensors wearing out to new sensors being inserted into the network, or even due to designers moving sensors around during a network re-design phase (for example, in response to a change in the requirements of the network. In this paper, we address the problem of covering a given path by a limited number of sensors — in our case to two, and show its relation to the well-studied matrix multiplication problem.
Energy Technology Data Exchange (ETDEWEB)
McAllindon, D. [Atomic Energy of Canada Limited, Darlington NGD, Bowmanville, ON (Canada); Sloan, D. [Ontario Hydro Nuclear, Darlington NGD, Bowmanville, ON (Canada); Mayer, P. [Ontario Hydro Technologies, Toronto, ON (Canada)
Resistance Temperature Detectors (RTDs) and their measurement circuit components have been a significant maintenance item at Darlington. Analysis of the problems has shown that RTDs and electrical penetrations (EPs) have been the largest sources of faults. A failure mechanism in which the RTD electrical resistance shifts upward was identified as a major source of RTD failures, which prompted a detailed failure investigation by Ontario Hydro Technologies (OHT). The investigation concluded that the root cause failure mechanism is chlorine contamination of the platinum wire during manufacture which resulted in surface damage to the wire and flaking of the wire surface during operation. Electrical penetrations in Darlington are of a pre-built modular design with two crimps internal to the EP. Spurious resistance in poor quality crimps in the EPs lead to errors in resistance measurement. The problem led to a complex and costly job to insert new modules in existing spare EPs. (author)
MCNP: Photon benchmark problems
Energy Technology Data Exchange (ETDEWEB)
Whalen, D.J.; Hollowell, D.E.; Hendricks, J.S.
The recent widespread, markedly increased use of radiation transport codes has produced greater user and institutional demand for assurance that such codes give correct results. Responding to these pressing requirements for code validation, the general purpose Monte Carlo transport code MCNP has been tested on six different photon problem families. MCNP was used to simulate these six sets numerically. Results for each were compared to the set's analytical or experimental data. MCNP successfully predicted the analytical or experimental results of all six families within the statistical uncertainty inherent in the Monte Carlo method. From this we conclude that MCNP can accurately model a broad spectrum of photon transport problems. 8 refs., 30 figs., 5 tabs.
Directory of Open Access Journals (Sweden)
Pešić Jelena M.
Full Text Available This paper deals with various reasons for treating the problematisation of textbook discourse as an important aspect of its educational design. These reasons are derived from: the nature of learning process, the nature of scientific knowledge and both motivational and cognitive saint achieved through a problematisation of learning material. Implications drawn from these considerations, along with textbook genre possibilities and constrains, lead us to define some basic strategies of textbook discourse problematisation. They refer to: way of presenting knowledge (problem structuring of text, presenting the history of knowledge and different perspectives; use of specific questions and tasks; metacognitive support of the learning process and specific type of textbook language (dialogical problem focused, language of thinking.
DEFF Research Database (Denmark)
Hansen, David
Many industrial production work systems have increased in complexity, and their new business model scompete on innovation, rather than low cost.At a medical device production facility committed to Lean Production, a research project was carried out to use Appreciative Inquiry to better engage...... employee strengths in continuou simprovements of the work system. The research question was: "How can Lean problem solving and Appreciative Inquiry be combined for optimized work system innovation?" The research project was carried out as a co-creation process with close cooperation between researcher...... and participants and was documented by qualitative methods. This paper presents an academic literature review on Appreciative Inquiry and problem solving for continuous improvements that did not reveal successful attempts in combining the two.Both the literature and the empirical study showed one of the main...
Directory of Open Access Journals (Sweden)
Tjandra Y. Aditama
Full Text Available Smoking is an important public health probLem in Indonesia. Up to 60% of male adult population as well as about 4% of female adult population are smokers. In fact, some of Indonesian kretek cigarettes have quite high tar and nicotine content. Besides health effect, smoking habit also influence economic status of the individuals as well as the family. In health point of view, even though reliable nation wide morbidity and mortality data are scarce, report from various cities showed smoking related diseases, such as Lung cancer, COPD, effect of pregnancy, etc. Other problem is a fact that smoking habit start quite in early age in Indonesia. This article also describe factors complicate smoking control program as well as several things to be done to strengthen smoking control program in Indonesia. (Med J Indones 2002; 11: 56-65Keywords : smoking, Indonesia, impact
Enumula, Prabodh K
This paper proposes the Potluck Problem as a model for the behavior of independent producers and consumers under standard economic assumptions. We model this by using resource allocation in a multi-agent system in which there is no explicit communication among the agents. The model proposed has many applications in modeling systems like electrical power grids with many consumers and producers, service-on-demand in grid computing and peer-to-peer computing environments, maintaining a good ratio between demand and inventory in supply chain management, etc. It is observed that a rational learning approach is unable to achieve equilibrium or near-equilibrium in the Potluck Problem. Instead, a weighted majority learning algorithm is applied, which does much better in maintaining parity of supply and demand in varying-demand situations.
Europeanisation: Solution or problem?
Directory of Open Access Journals (Sweden)
Claudio M. Radaelli
Full Text Available Is there something new in recent research on Europeanisation? Or should we go back to what we already know about political integration in Europe and avoid the term? This article reviews recent work in four steps: the identification of the specific domain of Europeanisation; the relationship between Europeanisation, on the one hand, and governance, institutions, and discourse, on the other; the methodological problems and the models emerging in this new field of research; and an assessment of the results arising out of theoretical and empirical research. One theme throughout the article is that, in order to develop a progressive agenda, Europeanisation should be seen as a problem, not as a solution. It is neither a new theory, nor an ad-hoc approach. Rather, it is a way of orchestrating existing concepts and to contribute to cumulative research in political science. Europeanisation does not provide any simple fix to theoretical or empirical problems. Quite the opposite, it can deliver if approached as a set of puzzles. A problem in search of explanation not the explanation itself (Gualini 2003. The conclusion is that Europeanisation has contributed to the emergence of new insights, original explanations, and interesting questions on three important issues: the understanding and analysis of 'impact', how to endogeneise international governance in models of domestic politics, and the relationship between agency and change. These three issues are prominent in the research agendas of international relations, theoretical policy analysis, and comparative politics. To contribute to major issues at the core of political science is a valuable result for a relatively new field of inquiry.
International Nuclear Information System (INIS)
The collection comprises the materials of working meeting 'The Development of Technologies of the 'Ukrytie' Radioactive Waste Management', held on May 20-21, 1997 in Chernobyl. The results of research work of the experts of Ukraine and other countries directed on solving problems, concerning removal of fuel containing materials and other radioactive waste from destroyed Unit 4 of Chernobyl NPP are given. The data on waste quantities, their location and classification, strategy of waste management and some technologies are described
Santos, Emilio
The problem of hidden variables in quantum mechanics is formalized as follows. A general or contextual (noncontextual) hidden-variables theory is defined as a mapping f: Q×M → C (f: Q→C) where Q is the set of projection operators in the appropriate (quantum) Hilbert space, M is the set of maximal Boolean subalgebras of Q and C is a (classical) Boolean algebra. It is shown that contextual (noncontextual) hidden-variables always exist (do not exist).
Tjandra Y Aditama
Smoking is an important public health probLem in Indonesia. Up to 60% of male adult population as well as about 4% of female adult population are smokers. In fact, some of Indonesian kretek cigarettes have quite high tar and nicotine content. Besides health effect, smoking habit also influence economic status of the individuals as well as the family. In health point of view, even though reliable nation wide morbidity and mortality data are scarce, report from various cities showed smoking rel...
Creativity and problem Solving
Directory of Open Access Journals (Sweden)
René Victor Valqui Vidal
Full Text Available This paper presents some modern and interdisciplinary concepts about creativity and creative processes of special relevance for Operational Research workers. Central publications in the area Creativity-Operational Research are shortly reviewed. Some creative tools and the Creative Problem Solving approach are also discussed. Finally, some applications of these concepts and tools are outlined. Some central references are presented for further study of themes related to creativity or creative tools.
Lau, August; Yin, Chuan
Classical approach of solvability problem has shed much light on what we can solve and what we cannot solve mathematically. Starting with quadratic equation, we know that we can solve it by the quadratic formula which uses square root. Polynomial is a generalization of quadratic equation. If we define solvability by using only square roots, cube roots etc, then polynomials are not solvable by radicals (square root, cube root etc). We can classify polynomials into simple (solvable by radicals)...
Kulturwissenschaftliche Probleme internationaler Managementforschung
Janzer, Alexander
Diplom-Kulturwirt Alexander Janzer untersucht kulturwissenschaftliche Probleme der internationalen Managementforschung, die ihrerseits methodisch besonders häufig auf kulturvergleichende Umfrageforschung zurückgreift. This paper presents the most common errors of cross-cultural management research. Research in this field is based primarily on the concepts and methods of cross-cultural psychology (e.g. Hofstede 1980, Schwartz 1994, Triandis 1980). It is shown how current research from the C...
Ruskey, Frank; Williams, Aaron
In the classic Josephus problem, elements 1, 2,...,n are placed in order around a circle and a skip value k is chosen. The problem proceeds in n rounds, where each round consists of traveling around the circle from the current position, and selecting the kth remaining element to be eliminated from the circle. After n rounds, every element is eliminated. Special attention is given to the last surviving element, denote it by j. We generalize this popular problem by introducing a uniform number of lives ℓ, so that elements are not eliminated until they have been selected for the ℓth time. We prove two main results: 1) When n and k are fixed, then j is constant for all values of ℓ larger than the nth Fibonacci number. In other words, the last surviving element stabilizes with respect to increasing the number of lives. 2) When n and j are fixed, then there exists a value of k that allows j to be the last survivor simultaneously for all values of ℓ. In other words, certain skip values ensure that a given position is the last survivor, regardless of the number of lives. For the first result we give an algorithm for determining j (and the entire sequence of selections) that uses O(n 2) arithmetic operations.
Random eigenvalue problems revisited
Indian Academy of Sciences (India)
S Adhikari
The description of real-life engineering structural systems is associated with some amount of uncertainty in specifying material properties, geometric parameters, boundary conditions and applied loads. In the context of structural dynamics it is necessary to consider random eigenvalue problems in order to account for these uncertainties. Within the engineering literature, current methods to deal with such problems are dominated by approximate perturbation methods. Some exact methods to obtain joint distribution of the natural frequencies are reviewed and their applicability in the context of real-life engineering problems is discussed. A new approach based on an asymptotic approximation of multi-dimensional integrals is proposed. A closed-form expression for general order joint moments of arbitrary numbers of natural frequencies of linear stochastic systems is derived. The proposed method does not employ the 'small randomness' assumption usually used in perturbation based methods. Joint distributions of the natural frequencies are investigated using numerical examples and the results are compared with Monte Carlo simulation.
Medical problems of musicians.
Lockwood, A H
Surveys of performing musicians indicate that almost half of them experience playing-related medical problems, some of which threaten or end their careers. Overuse injuries involving the muscle--tendon unit are the most common problem, with symptoms ranging from mild pain while the musician is playing to pain severe enough to preclude any use of the affected hand. String players are the most commonly affected, and percussionists the least. The most important predisposing characteristic is the use of repetitive movements during long hours of practice, but awkward body positions mandated by the shape and weight of the instrument, the technical difficulty of the repertoire, and unfamiliar instruments may also play a part. Women are more commonly affected than men. Rest is the cornerstone of therapy. Neural impingement syndromes affecting the median or ulnar nerves or the thoracic outlet affect many musicians. Focal dystonias may involve part or all of a hand or the muscles forming the embouchure (the position of the lips in wind players). These are very resistant to therapy and may terminate or drastically alter a career. Stress, especially performance anxiety, may impede performance. Beta-adrenergic blocking agents prevent the symptoms of performance anxiety and are frequently used by musicians without medical supervision. A recognition of the unique problems of musician-patients has led to the formation of successful specialty clinics in a number of cities. PMID:2643048
Characteristics of Problems in Problem-based Learning
N. Sockalingam (Nachamma)
textabstractThis thesis focuses on characteristics of problems in Problem-based Learning (PBL). Problems initiate the students' learning process in PBL. Several studies have shown that the quality of problems has a positive influence on students' academic achievement and interest. In addition, the q
Obstacle problems in mathematical physics
Rodrigues, J-F
The aim of this research monograph is to present a general account of the applicability of elliptic variational inequalities to the important class of free boundary problems of obstacle type from a unifying point of view of classical Mathematical Physics.The first part of the volume introduces some obstacle type problems which can be reduced to variational inequalities. Part II presents some of the main aspects of the theory of elliptic variational inequalities, from the abstract hilbertian framework to the smoothness of the variational solution, discussing in general the properties of the free boundary and including some results on the obstacle Plateau problem. The last part examines the application to free boundary problems, namely the lubrication-cavitation problem, the elastoplastic problem, the Signorini (or the boundary obstacle) problem, the dam problem, the continuous casting problem, the electrochemical machining problem and the problem of the flow with wake in a channel past a profile.
Characteristics of Problems in Problem-based Learning
Sockalingam, Nachamma
textabstractThis thesis focuses on characteristics of problems in Problem-based Learning (PBL). Problems initiate the students' learning process in PBL. Several studies have shown that the quality of problems has a positive influence on students' academic achievement and interest. In addition, the quality of problems has been shown to have a higher influence than the tutor's performance and students' prior knowledge on students' learning. The implication of these findings is that designing go...
Space Power Engineering Problems
Senkevich, V. P.
Development of space power engineering in the first half of XXI century shall be aimed at preventing the forthcoming energy crisis and ecological catastrophes. The problem can be solved through using solar energy being perpetual, endless, and ecologically safe. As of now, issues on the development and employment of solar power stations and its beaming to the ground stations in the SHF band are put on the agenda. The most pressing problem is to develop orbital solar reflectors to illuminate towns in the polar regions, agricultural regions, and areas of processing sea products. Space-based technologies can be used to deal with typhoons, green house effects, and "ozone holes". Recently, large, frameless film structures formed by centrifugal forces offer the promise of structures for orbital power plants, reflectors, and solar sails. A big success is achieved in the development of power generating solar array elements of amorphous silicon. These innovations would make the development of orbital solar power plants dozens of times cheaper. Such solar arrays shall be used in the nearest future on heavy communication satellites and the Earth remote sensing platforms for generation of 140-160 kW at a specific power beyond 300 W/kg. The cargo traffic needed to develop and maintain the orbital power plants and reflector systems could be equipped with solar sails as the future low thrust propulsion. In 2000, the mankind witnessed an unexpected beginning of energy crisis along with strong hydro- meteorological events (typhoons, floods) that shocked the USA, the Western Europe, England, Japan, and other countries. The total damage is estimated as 90 billions of dollars. The mankind is approaching a boundary beyond which its further existence would depend on how people would learn to control weather and use ecologically safe power sources. Space technology base on the research potential accumulated in the previous century could serve for the solution of this problem.
Sperling, J.; Vogel, W
In 1927 the great physicist Paul A. M. Dirac failed to provide a consistent quantum description of the phase of a radiation field. Only one year later, he developed the famous Dirac theory of the electron, which led to the anti-particle -- the positron. We show that the reason for Dirac's failure with the phase problem bears a striking resemblance to his ingenious insight into the nature of the electron. For a correct quantum description of the phase of a radiation field it is necessary to ta...
Mechanics: Ideas, problems, applications
Ishlinskii, A. Iu.
The book contains the published articles and reports by academician Ishlinskii which deal with the concepts and ideas of modern mechanics, its role in providing a general understanding of the natural phenomena, and its applications to various problems in science and engineering. Attention is given to the methodological aspects of mechanics, to the history of the theories of plasticity, friction, gyroscopic and inertial systems, and inertial navigation, and to mathematical methods in mechanics. The book also contains essays on some famous scientists and engineers.
The Gilbert Arborescence Problem
Volz, M G; Ras, C J; Swanepoel, K J; Thomas, D A
We investigate the problem of designing a minimum cost flow network interconnecting n sources and a single sink, each with known locations and flows. The network may contain other unprescribed nodes, known as Steiner points. For concave increasing cost functions, a minimum cost network of this sort has a tree topology, and hence can be called a Minimum Gilbert Arborescence (MGA). We characterise the local topological structure of Steiner points in MGAs, showing, in particular, that for a wide range of metrics and cost-functions the degree of each Steiner point is 3.
Amiano, Mitch; Ethier, Kay; Thomas, Michael D
Offering a unique approach to learning XML, this book walks readers through the process of building a complete, functional, end-to-end XML solutionFeatured case study is an online business product catalog that includes reports, data input/output, workflow, stylesheet formatting, RSS feeds, and integration with external services like Google, eBay, and AmazonThe format of presenting a problem and working through the design to come up with a solution enables readers to understand how XML markup allows a business to share data across applications internally or with partners or customers even thoug
Elementary topology problem textbook
Viro, O Ya; Netsvetaev, N Yu; Kharlamov, V M
This textbook on elementary topology contains a detailed introduction to general topology and an introduction to algebraic topology via its most classical and elementary segment centered at the notions of fundamental group and covering space. The book is tailored for the reader who is determined to work actively. The proofs of theorems are separated from their formulations and are gathered at the end of each chapter. This makes the book look like a pure problem book and encourages the reader to think through each formulation. A reader who prefers a more traditional style can either find the pr
DEFF Research Database (Denmark)
Janstrup, Kira
The main purpose of this project is to use integer programming to create a model that minimizes the costs for container transportation by ship. To make the model as realistic as possible it will be based on information from a large shipping company about the vessel layout and container types....... In addition to our project two other projects are made where an optimal solution to the container stowage problem also is tried to be found, but by using constraint programming and local search instead respectively. We will therefore in the end compare these three methods and the achieved results on fastness...
DEFF Research Database (Denmark)
Janstrup, Kira; Rose, Trine Høyer; Andersen, Kent Høj;
The main purpose of this project is to use integer programming to create a model that minimizes the costs for container transportation by ship. To make the model as realistic as possible it will be based on information from a large shipping company about the vessel layout and container types....... In addition to our project two other projects are made where an optimal solution to the container stowage problem also is tried to be found, but by using constraint programming and local search instead respectively. We will therefore in the end compare these three methods and the achieved results on fastness...
Deser, S; Ong, Y C; Waldron, A
The method of characteristics is a key tool for studying consistency of equations of motion; it allows issues such as predictability, maximal propagation speed, superluminality, unitarity and acausality to be addressed without requiring explicit solutions. We review this method and its application to massive gravity theories to show the limitations of these models' physical viability: Among their problems are loss of unique evolution, superluminal signals, matter coupling inconsistencies and micro-acausality (propagation of signals around local closed timelike/causal curves). We extend previous no-go results to the entire three-parameter range of massive gravity theories. It is also argued that bimetric models suffer a similar fate.
Drevenšek, Sanja
Korupcija je kompleksen pojav in vse večji problem v vseh državah tudi v Sloveniji. Pojavlja se v različnih oblikah, njene posledice pa so uničujoče za širšo družbo, državo kakor tudi za vsakega posameznika. Problematika je sicer v Sloveniji urejena z zakonodajo, ki je primerljiva z evropsko zakonodajo o preprečevanju korupcije. Ustanovljeno imamo tudi Komisijo za preprečevanje korupcije kot samostojen in neodvisen državni organ, katerega temeljno poslanstvo je doseči ničelno toleranco do kor...
Schistosomiasis: progress and problems
Institute of Scientific and Technical Information of China (English)
George Y. Wu; Mohab H. Halim
@@ INTRODUCTION Schistosomiasis, also commonly known as bilharziasis, is one of the most significant parasitic diseases of humans. A report of World Health Organization in 1996 estimated that over 200 million people were infested worldwide, mainly in rural agricultural and periurban areas. Of these, 20 million suffer severe consequences from the disease and 120 million are symptomatic. Symptoms range from fever, headache and lethargy, to severe sequelae including ascites, hepatosplenomegaly and even death[1]. More than 600 million people in the tropics are at risk for developing schistosomiasis.Schistosomiasis is the major public health problem in rural Egypt, with almost six million Egyptians are infested[2].
Gao, Keyue
This paper deals with a problem in which two players share a previously sliced pizza and try to eat as much amount of pizza as they can. It takes time to eat each piece of pizza and both players eat pizza at the same rate. One is allowed to take a next piece only after the person has finished eating the piece on hand. Also, after the first piece is taken, one can only take a piece which is adjacent to already-taken piece. This paper shows that, in this real time setting, the starting player c...
Analysis of the tracing problem
Institute of Scientific and Technical Information of China (English)
Nanfeng Jie; Hui Wang; YunqingSun
Here the tracing problems are researched from two thoroughly different approaches: calculus method and numerical analysis. Generally speaking, the calculus method give a universal qualitative way to deal with such kind of problem, but the numerical analysis method can offer more further quantitative result for such kind of problem. Our research shows the detail results of application of these two methods in tracing problem.
Problem Order Implications for Learning
Li, Nan; Cohen, William W.; Koedinger, Kenneth R.
The order of problems presented to students is an important variable that affects learning effectiveness. Previous studies have shown that solving problems in a blocked order, in which all problems of one type are completed before the student is switched to the next problem type, results in less effective performance than does solving the problems…
Extended Mixed Vector Equilibrium Problems
Directory of Open Access Journals (Sweden)
Mijanur Rahaman
Full Text Available We study extended mixed vector equilibrium problems, namely, extended weak mixed vector equilibrium problem and extended strong mixed vector equilibrium problem in Hausdorff topological vector spaces. Using generalized KKM-Fan theorem (Ben-El-Mechaiekh et al.; 2005, some existence results for both problems are proved in noncompact domain.
Decomposition Approaches for Optimization Problems
Kinable, Joris
This dissertation encompasses the development of decomposition approaches for a variety of both real-world and fundamental optimization problems. Many optimization problems comprise of multiple interconnected subproblems, often rendering them too large or too complicated to solve as a single integral problem. Decomposition approaches are required to deal with these problems efficiently. By decomposing a problem into multiple subproblems, efficient dedicated procedures can be employed to solve...
Some Undecidable Problems on Approximability of NP Optimization Problems
Institute of Scientific and Technical Information of China (English)
In this paper some undecidable problems on approximability of NP optimization problems are investigated.In particular,the following problems are all undecidable:(1) Given an NP optimization problem,is it approximable in polynomial time?(2)For any polynomial-time computable function r(n),given a polynomial time approximable NP optimization problem,has it a polynomial-time approximation algorithm with approximation performance ratio r(n) (r(n)-approximable)?(3)For any polynomial-time computable functions r(n),r'(n),where r'(n)
Understanding the Problem. Problem Solving and Communication Activity Series. The Math Forum: Problems of the Week
Math Forum @ Drexel, 2009
Different techniques for understanding a problem can lead to ideas for never-used-before solutions. Good problem-solvers use a problem-solving strategy and may come back to it frequently while they are working on the problem to refine their strategy, see if they can find better solutions, or find other questions. Writing is an integral part of…
Edmondson, Amy C
Companies today increasingly rely on teams that span many industries for radical innovation, especially to solve "wicked problems." So leaders have to understand how to promote collaboration when roles are uncertain, goals are shifting, expertise and organizational cultures are varied, and participants have clashing or even antagonistic perspectives. HBS professor Amy Edmondson has studied more than a dozen cross-industry innovation projects, among them the creation of a new city, a mango supply-chain transformation, and the design and construction of leading-edge buildings. She has identified the leadership practices that make successful cross-industry teams work: fostering an adaptable vision, promoting psychological safety, enabling knowledge sharing, and encouraging collaborative innovation. Though these practices are broadly familiar, their application within cross-industry teams calls for unique leadership approaches that combine flexibility, open-mindedness, humility, and fierce resolve.
Edmondson, Amy C
Companies today increasingly rely on teams that span many industries for radical innovation, especially to solve "wicked problems." So leaders have to understand how to promote collaboration when roles are uncertain, goals are shifting, expertise and organizational cultures are varied, and participants have clashing or even antagonistic perspectives. HBS professor Amy Edmondson has studied more than a dozen cross-industry innovation projects, among them the creation of a new city, a mango supply-chain transformation, and the design and construction of leading-edge buildings. She has identified the leadership practices that make successful cross-industry teams work: fostering an adaptable vision, promoting psychological safety, enabling knowledge sharing, and encouraging collaborative innovation. Though these practices are broadly familiar, their application within cross-industry teams calls for unique leadership approaches that combine flexibility, open-mindedness, humility, and fierce resolve. PMID:27491195
International Nuclear Information System (INIS)
This collection comprises the materials of the VI International Conference 'Shelter' Object', 15 years: today and future'. The topics of this issue's works cover the results of 15-year operation of the Shelter Object and investigations of conditions of its nuclear-, radiation- and general technical safety, procedures of monitoring of fuel-containing material conditions, building structures, problems of object's conversion into an ecologically safe system, preparation of technologies for radwaste (RW) management, working out of procedures using the remotely controlled facilities for diagnostics, prospecting of complicated in access Shelter Object premises, RW retrieval and management, etc. A very important role play the works aimed at the upgrade of radiation safety, protection of public and environment
Instrumentation problems for physicians.
Turner, G O
The physician has, for whatever reasons, diminished his or her level of involvement on the team dedicated to developing, refining, and evaluating medical technology. As a result, the challenge confronting the physician and the technology development team today is to orchestrate a team structure that will ensure the greatest input and commitment from physicians and other professionals during current and future technology development. The charges of cost escalation and dehumanization in our system of health care delivery will also be discussed, as will the lack of, or confusion about, access to data concerning cost of a given instrument, and fuzzy semantics and perspectives on technology and instrumentation. The author suggests answers to, or means to ameliorate, the problems.
Directory of Open Access Journals (Sweden)
H. Williams
Full Text Available It will help delegates to realize something of the range and magnitude of Service equipment problems if I touch on a few of the many important items which concern the Corps of Engineers in their preparations for war. The Engineers' role in battle is to assist our own forces to maintain their mobility by the passage of obstacles of every, description, the construction of roads and tracks and by meeting the Air Force's requirements airfields and air-strips. Secondly, to deny mobility to the enemy's forces by creating obstacles by demolitions and the destruction of materials, and by the construction of weapon positions and shelters. And lastly to support the administrative machine by supplying water, bulk fuel, power and Engineer stores where required, by meeting the Army's Transportation needs and in numerous other ways dependent on Engineering.
Directory of Open Access Journals (Sweden)
William Margulies
Full Text Available In this paper, we study a specific stochastic differential equation depending on a parameter and obtain a representation of its probability density function in terms of Jacobi Functions. The equation arose in a control problem with a quadratic performance criteria. The quadratic performance is used to eliminate the control in the standard Hamilton-Jacobi variational technique. The resulting stochastic differential equation has a noise amplitude which complicates the solution. We then solve Kolmogorov's partial differential equation for the probability density function by using Jacobi Functions. A particular value of the parameter makes the solution a Martingale and in this case we prove that the solution goes to zero almost surely as time tends to infinity.
Energy Technology Data Exchange (ETDEWEB)
Walkup, Elizabeth [Stanford Univ., CA (United States)
Passwords are an ubiquitous, established part of the Internet today, but they are also a huge security headache. Single sign-on, OAuth, and password managers are some of the solutions to this problem. OAuth is a new, popular method that allows people to use large, common authentication providers for many web applications. However, it comes at the expense of some privacy: OAuth makes users easy to track across websites, applications, and devices. Password managers put the power in the hands of the users, but this vulnerability survey reveals that you have to be extremely careful which program you choose. All in all, password managers are the solution of choice for home users and small organizations, but large companies will probably want to invest in their own SSO solutions.
Mauroy, Alexandre; Taslakian, Perouz; Langerman, Stefan; Jungers, Raphaël
A four-bar linkage is a mechanism consisting of four rigid bars which are joined by their endpoints in a polygonal chain and which can rotate freely at the joints (or vertices). We assume that the linkage lies in the 2-dimensional plane so that one of the bars is held horizontally fixed. In this paper we consider the problem of reconfiguring a four-bar linkage using an operation called a pop. Given a four-bar linkage, a pop reflects a vertex across the line defined by its two adjacent vertices along the polygonal chain. Our main result shows that for certain conditions on the lengths of the bars, the neighborhood of any configuration that can be reached by smooth motion can also be reached by pops. The proof relies on the fact that pops are described by a map on the circle with an irrational number of rotation.
Lau, August
Classical approach of solvability problem has shed much light on what we can solve and what we cannot solve mathematically. Starting with quadratic equation, we know that we can solve it by the quadratic formula which uses square root. Polynomial is a generalization of quadratic equation. If we define solvability by using only square roots, cube roots etc, then polynomials are not solvable by radicals (square root, cube root etc). We can classify polynomials into simple (solvable by radicals) and complex (not solvable by radicals). We will use the same metaphor to separate what is solvable (simple part) and what is not solvable (complex part). This paper is a result of our presentation at a University of Houston seminar. In this paper, we will study seismic complexity through the eyes of solvability. We will investigate model complexity, data complexity and operator complexity. Model complexity is demonstrated by multiple scattering in a complex model like Cantor layers. Data complexity is studied through Bet...
DEFF Research Database (Denmark)
Görlich, Anne; Katznelson, Noemi; Stentoft, Mette
Uddannelsessystemet rummer i dag en stor del af de sårbare og udsatte unge, der tidligere havde ufaglærte jobs eller var på kontanthjælp. Det skaber udfordringer i forhold til den politiske målsætning om, at 95 procent af en ungdomsårgang skal gennemføre en ungdomsuddannelse. Disse udfordringer har...... været omdrejningspunktet i Skive Kommunes projekt 'Fra problemer til mirakler', hvor man har søgt at styrke sårbare unges selvtillid, motivation for og deltagelse i en kompetencegivende uddannelse og dermed holde dem ude af kontanthjælpssystemet....
Institute of Scientific and Technical Information of China (English)
G. Shanmugam
The synonymous use of the general term"landslide", with a built-in reference to a sliding motion, for all varieties of mass-transport deposits (MTD), which include slides, slumps, debrites, topples, creeps, debris avalanches etc. in subaerial, sublacustrine, sub-marine, and extraterrestrial environments has created a multitude of conceptual and nomen-clatural problems. In addition, concepts of triggers and long-runout mechanisms of mass movements are loosely applied without rigor. These problems have enormous implications for studies in process sedimentology, sequence stratigraphy, palaeogeography, petroleum geol-ogy, and engineering geology. Therefore, the objective of this critical review is to identify key problems and to provide conceptual clarity and possible solutions. Speciifc issues are the fol-lowing:(1) According to"limit equilibrium analyses"in soil mechanics, sediment failure with a sliding motion is initiated over a shear surface when the factor of safety for slope stability (F) is less than 1. However, the term landslide is not meaningful for debris lfows with a lfowing mo-tion. (2) Sliding motion can be measured in oriented core and outcrop, but such measurement is not practical on seismic proifles or radar images. (3) Although 79 MTD types exist in the geological and engineering literature, only slides, slumps, and debrites are viable depositional facies for interpreting ancient stratigraphic records. (4) The use of the term landslide for high-velocity debris avalanches is inappropriate because velocities of mass-transport processes cannot be determined in the rock record. (5) Of the 21 potential triggering mechanisms of sediment failures, frequent short-term events that last for only a few minutes to several hours or days (e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.) are more relevant in controlling deposition of deep-water sands than sporadic long-term events that last for thousands to millions of years (e
International Nuclear Information System (INIS)
Members of the Institute have worked on a number of problems including the following: acceleration algorithms for the Monte Carlo analysis of lattice field, and gauge and spin theories, based on changes of variables specific to lattices of dimension 2ell; construction of quaternionic generalizations of complex quantum mechanics and field theory; wave functions for paired Hall states; black hole quantum mechanics; generalized target-space duality in curved string backgrounds; gauge symnmetry algebra of the N = 2 string; two-dimensional quantum gravity and associated string theories; organizing principles from which the signal processing of neural networks in the retina and cortex can be deduced; integrable systems of KdV type; and a theory for Kondo insulators
Directory of Open Access Journals (Sweden)
Erik af Edholm
Full Text Available The myth of the recurrence of the golden age after a period of accelerating miseries ("messianic woes" in the near future is of course not peculiar to the chiliasm of the European later middle ages. On the contrary, it belongs to the basic eschatological themes of millenarism in general. These themes are found also in Hindu tradition. To determine those general characteristics of traditional Hindu society which can contribute to an explanation of the relative unimportance of peasant rebellions and the lack of chiliastic mass movements, is not a problem to be solved within the field of the history of religions. For example, the egalitarian message of the bhakti saints, disputing the hierarchy, did not preclude that the salvationist sects did adapt to the caste system. The religious movements contributed to and gave ideological form to adjustments within the existing social structure. Obviously there was little need for millenarism in this process.
Muna, Demitri; Allen, Alice; Ashley, Richard; Asmus, Daniel; Azzollini, Ruyman; Bannister, Michele; Beaton, Rachael; Benson, Andrew; Berriman, G Bruce; Bilicki, Maciej; Boyce, Peter; Bridge, Joanna; Cami, Jan; Cangi, Eryn; Chen, Xian; Christiny, Nicholas; Clark, Christopher; Collins, Michelle; Comparat, Johan; Cook, Neil; Croton, Darren; Davids, Isak Delberth; Depagne, Éric; Donor, John; Santos, Leonardo A dos; Douglas, Stephanie; Du, Alan; Durbin, Meredith; Erb, Dawn; Faes, Daniel; Fernández-Trincado, J G; Foley, Anthony; Fotopoulou, Sotiria; Frimann, Søren; Frinchaboy, Peter; Garcia-Dias, Rafael; Gawryszczak, Artur; George, Elizabeth; Gonzalez, Sebastian; Gordon, Karl; Gorgone, Nicholas; Gosmeyer, Catherine; Grasha, Katie; Greenfield, Perry; Grellmann, Rebekka; Guillochon, James; Gurwell, Mark; Haas, Marcel; Hagen, Alex; Haggard, Daryl; Haines, Tim; Hall, Patrick; Hellwing, Wojciech; Herenz, Edmund Christian; Hinton, Samuel; Hlozek, Renee; Hoffman, John; Holman, Derek; Holwerda, Benne Willem; Horton, Anthony; Hummels, Cameron; Jacobs, Daniel; Jensen, Jens Juel; Jones, David; Karick, Arna; Kelley, Luke; Kenworthy, Matthew; Kitchener, Ben; Klaes, Dominik; Kohn, Saul; Konorski, Piotr; Krawczyk, Coleman; Kuehn, Kyler; Kuutma, Teet; Lam, Michael T; Lane, Richard; Liske, Jochen; Lopez-Camara, Diego; Mack, Katherine; Mangham, Sam; Mao, Qingqing; Marsh, David J E; Mateu, Cecilia; Maurin, Loïc; McCormac, James; Momcheva, Ivelina; Monteiro, Hektor; Mueller, Michael; Munoz, Roberto; Naidu, Rohan; Nelson, Nicholas; Nitschelm, Christian; North, Chris; Nunez-Iglesias, Juan; Ogaz, Sara; Owen, Russell; Parejko, John; Patrício, Vera; Pepper, Joshua; Perrin, Marshall; Pickering, Timothy; Piscionere, Jennifer; Pogge, Richard; Poleski, Radek; Pourtsidou, Alkistis; Price-Whelan, Adrian M; Rawls, Meredith L; Read, Shaun; Rees, Glen; Rein, Hanno; Rice, Thomas; Riemer-Sørensen, Signe; Rusomarov, Naum; Sanchez, Sebastian F; Santander-García, Miguel; Sarid, Gal; Schoenell, William; Scholz, Aleks; Schuhmann, Robert L; Schuster, William; Scicluna, Peter; Seidel, Marja; Shao, Lijing; Sharma, Pranav; Shulevski, Aleksandar; Shupe, David; Sifón, Cristóbal; Simmons, Brooke; Sinha, Manodeep; Skillen, Ian; Soergel, Bjoern; Spriggs, Thomas; Srinivasan, Sundar; Stevens, Abigail; Streicher, Ole; Suchyta, Eric; Tan, Joshua; Telford, O Grace; Thomas, Romain; Tonini, Chiara; Tremblay, Grant; Tuttle, Sarah; Urrutia, Tanya; Vaughan, Sam; Verdugo, Miguel; Wagner, Alexander; Walawender, Josh; Wetzel, Andrew; Willett, Kyle; Williams, Peter K G; Yang, Guang; Zhu, Guangtun; Zonca, Andrea
The Astropy Project (http://astropy.org) is, in its own words, "a community effort to develop a single core package for Astronomy in Python and foster interoperability between Python astronomy packages." For five years this project has been managed, written, and operated as a grassroots, self-organized, almost entirely volunteer effort while the software is used by the majority of the astronomical community. Despite this, the project has always been and remains to this day effectively unfunded. Further, contributors receive little or no formal recognition for creating and supporting what is now critical software. This paper explores the problem in detail, outlines possible solutions to correct this, and presents a few suggestions on how to address the sustainability of general purpose astronomical software.
Radiological problems in Kazakhstan
International Nuclear Information System (INIS)
Kazakhstan historical development and available mineral resources have pre-determined a scale of radiological problems in the state. Kazakhstan keeps leading positions in the world in explored uranium resources and hydrocarbon raw. More than five hundred nuclear explosions were performed in various regions of Kazakhstan. There is necessity to carry out remediation actions at the former test sites of Kazakhstan, especially at the Semipalatinsk test-site (STS). But because of the high cost of such actions it should be expedient to carry out them only in case of emergency and inclusion of the former test sites lands to the national economic activity, as in general, under conditions of competent policy of inhabitants, STS doesn't represent a hazard. At the same time, we ought not to lose an invaluable scientific material of test-sites. It is necessary to keep some areas of Semipalatinsk test-site as a rarities, reflected the important stages of the human evolution. Test-sites should be considered as world laboratory for studies of artificial radionuclides behaviour in natural medium. Illustrations of radiation-hazardous objects, of used technologies and procedures, under the Kazakhstan Republic instance, show that main power industries lead to the common increase of radioactivity materials in human environment. Mankind certainly will become aware of fact that industrial activities, under the current level of science and technologies development, will lead to the common increase of radioactivity materials in human environment. Solving of radioecological problems is possible only when people review their approach to a radioactivity, as a whole. Not only specialists involved in this field, but also all local population have to know rules of radiation safety and how reasonable manage with radioactive materials
Institute of Scientific and Technical Information of China (English)
ZENG; Jiwen(
[1]Brauer, R., Representations of finite groups, in Lectures in Mathematics, Vol. 1, New York: Wiley, 1963, 133-175.[2]Feit, W. , The Representation Theory of Finite Groups, Amsterdam: North-Holland, 1982.[3]Külshammer, B., Landau's theorem for p-blocks of p-solvable groups, J. Reine Angew. Math., 1990, 404: 189-191.[4]Külshammer B., Robinson, G. R., Alperin-Mckey implies Brauer's problem 21, J. Algebra, 1996, 180: 208-210.[5]Zeng Jiwen, An inequality of block invariants, J. Algebra, 1997, 193: 724-727.[6]Nagao, N., Tsushima, Y., Representations of Finite Groups, New York: Academic Press, Inc., 1989.[7]Robinson, G. R., On Brauer's k(B) problem, J. Algebra, 1992, 147: 450-455.[8]Zhang Jiping, p-regular orbits and p-blocks of defect zero, Comm. Algebra, 1993, 21(1): 299-307.[9]Xu Minyao, Huang ,Jianhua, An Introduction to Finite Groups (in Chinese), Vol. 2, Beijing: Science Press, 1999.[10]Alperin, ,J. L. , Weights for finite group, Proc. Sympos. Pure Math. , 1987, 47: 369-379.[11]Puig, L., Usami, Y., Perfect isometrics for blocks with Abelian defect groups and cyclic four inertial quotients, J. Algebra,1996.[12]Dade, E. C., Counting characters in blocks, I, Invent. Math., 1992, 109: 187-210.
The worldwide "wildfire" problem.
Gill, A Malcolm; Stephens, Scott L; Cary, Geoffrey J
The worldwide "wildfire" problem is headlined by the loss of human lives and homes, but it applies generally to any adverse effects of unplanned fires, as events or regimes, on a wide range of environmental, social, and economic assets. The problem is complex and contingent, requiring continual attention to the changing circumstances of stakeholders, landscapes, and ecosystems; it occurs at a variety of temporal and spatial scales. Minimizing adverse outcomes involves controlling fires and fire regimes, increasing the resistance of assets to fires, locating or relocating assets away from the path of fires, and, as a probability of adverse impacts often remains, assisting recovery in the short-term while promoting the adaptation of societies in the long-term. There are short- and long-term aspects to each aspect of minimization. Controlling fires and fire regimes may involve fire suppression and fuel treatments such as prescribed burning or non-fire treatments but also addresses issues associated with unwanted fire starts like arson. Increasing the resistance of assets can mean addressing the design and construction materials of a house or the use of personal protective equipment. Locating or relocating assets can mean leaving an area about to be impacted by fire or choosing a suitable place to live; it can also mean the planning of land use. Assisting recovery and promoting adaptation can involve insuring assets and sharing responsibility for preparedness for an event. There is no single, simple, solution. Perverse outcomes can occur. The number of minimizing techniques used, and the breadth and depth of their application, depends on the geographic mix of asset types. Premises for policy consideration are presented. PMID:23634593
Fostering Information Problem Solving Skills Through Completion Problems and Prompts
Frerejean, Jimmy; Brand-Gruwel, Saskia; Kirschner, Paul A.
Frerejean, J., Brand-Gruwel, S., & Kirschner, P. A. (2012, September). Fostering Information Problem Solving Skills Through Completion Problems and Prompts. Poster presented at the EARLI SIG 6 & 7 "Instructional Design" and "Learning and Instruction with Computers", Bari, Italy.
Fostering information problem solving skills through completion problems and prompts
Frerejean, Jimmy; Brand-Gruwel, Saskia; Kirschner, Paul A.
Frerejean, J., Brand-Gruwel, S., & Kirschner, P. A. (2012, November). Fostering information problem solving skills through completion problems and prompts. Poster presented at the ICO Fall School 2012, Girona, Spain.
Kolkata Restaurant Problem as a Generalised El Farol Bar Problem
Chakrabarti, Bikas K.
Generalisation of the El Farol bar problem to that of many bars here leads to the Kolkata restaurant problem, where the decision to go to any restaurant or not is much simpler (depending on the previous experience of course, as in the El Farol bar problem). This generalised problem can be exactly analysed in some limiting cases discussed here. The fluctuation in the restaurant service can be shown to have precisely an inverse cubic behavior, as widely seen in the stock market fluctuations.
Addressing problems of employee performance.
McConnell, Charles R
Employee performance problems are essentially of 2 kinds: those that are motivational in origin and those resulting from skill deficiencies. Both kinds of problems are the province of the department manager. Performance problems differ from problems of conduct in that traditional disciplinary processes ordinarily do not apply. Rather, performance problems are addressed through educational and remedial processes. The manager has a basic responsibility in ensuring that everything reasonable is done to help each employee succeed. There are a number of steps the manager can take to address employee performance problems.
Problem Solvers: Problem--How Long Can You Stand?
Teaching Children Mathematics, 2010
Healthy lifestyles are increasingly emphasized these days. This month the authors begin a series of mathematical problems that also address physical activity. They hope that these problems offer opportunities to investigate mathematics and also reinforce the desire to lead a healthy life. In their first problem of the academic year, students…
Problem Solving through an Optimization Problem in Geometry
Poon, Kin Keung; Wong, Hang-Chi
This article adapts the problem-solving model developed by Polya to investigate and give an innovative approach to discuss and solve an optimization problem in geometry: the Regiomontanus Problem and its application to football. Various mathematical tools, such as calculus, inequality and the properties of circles, are used to explore and reflect…
Problem effectiveness in a course using problem-based learning
D.H.J.M. Dolmans (Diana); W.H. Gijselaers (Wim); H.G. Schmidt (Henk); S.B. van der Meer
textabstractBackground. Problem-based learning (PBL) emphasizes active generation of learning issues by students. Both students and reachers, however, tend to worry that not all important knowledge will be acquired. To explore this question, problem effectiveness (i.e., for each problem, the degree
Dental Health and Orthodontic Problems
... Text Size Email Print Share Dental Health and Orthodontic Problems Page Content Article Body Dental Health Twin ... color can be tinted to match the teeth. Orthodontic Problems Crooked teeth, overbites and underbites are best ...
Feder, Tomás
Results on graph turnpike problem without distinctness, including its NP-completeness, and an O(m+n log n) algorithm, is presented. The usual turnpike problem has all pairwise distances given, but does not specify which pair of vertices w e corresponds to. There are two other problems that can be viewed as special cases of the graph turnpike problem, including the bandwidth problem and the low-distortion graph embedding problem. The aim for the turnpike problem in the NP-complete is to orient the edges with weights w i in either direction so that when the whole cycle is transversed in the real line, it returns to a chosen starting point for the cycle. An instance of the turnpike problem with or without distinctness is uniquely mappable if there exists at most one solution up to translation and choice of orientation.
Sherlock Holmes, Master Problem Solver.
Ballew, Hunter
Shows the connections between Sherlock Holmes's investigative methods and mathematical problem solving, including observations, characteristics of the problem solver, importance of data, questioning the obvious, learning from experience, learning from errors, and indirect proof. (MKR)
Dementia - behavior and sleep problems
Institute of Scientific and Technical Information of China (English)
Guangya CHEN
In this paper we define a concept of weak equilibrium for vector network equilibrium problems.We obtain sufficient conditions of weak equilibrium points and establish relation with vector network equilibrium problems and vector variational inequalities.
Eldercare at Home: Communication Problems
... improving it. It is never just one person's responsibility. Communication problems may require adjusting to new limitations and possibly ... lead to further loss of communication skills and social isolation. ... with communication problems but pay attention to the way they communicate ...
Eldercare at Home: Mobility Problems
... dementia, poor eyesight, or need for medication review. Obvious problems with gait and balance (such as a ... condition such as emphysema or infection, a stroke, depression, circulatory problems, or over-medication with sedatives or ...
Direct Problems and Inverse Problems in Biometric Systems
Directory of Open Access Journals (Sweden)
Mihailescu Marius Iulian
Full Text Available The article purpose is to describe the two sides of biometrics technologies, direct problems and inverse problems. The advance that we face today in field of Information Technology makes Information Security an inseparable part. The authentication has a huge role when we deal about security. The problems that can appear in implementing and developing biometrics systems is raising many problems, and one of the goal of this article is to focus on direct and inverse problems which is a new and challenging branch in biometrics technologies.
Terrorism and identity problem
Directory of Open Access Journals (Sweden)
Šijaković Ivan
Full Text Available Terrorism is phenomenon of modern society, which became expressive especially in second half of twentieth century. There is a real danger that it could increase in growing number of terrorist groups, their aims, arms and ways of work, and that it could effect also in twentieth first century. Terrorism endangers the most important product of modern times: democracy, freedom, and human rights. There are different causes and reasons for existing of terrorist organizations and their cruel terrorist actions. This text analyzes a question of identity as a possible reason for existing of different terrorist groups and organizations and for their actions. Search for identity and question how to defend it create different problems and difficulties for individuals and groups. That identity is one-sided, disported, based on a false faith and so called salvation, but, to defend it somebody is prepared to sacrifice everything, his own life if that is necessary (but frequently somebody else's. That way, terrorism can be understood as a way of defending that identity.
The Classical Electron Problem
Gill, T L; Lindesay, J
In this paper, we construct a parallel image of the conventional Maxwell theory by replacing the observer-time by the proper-time of the source. This formulation is mathematically, but not physically, equivalent to the conventional form. The change induces a new symmetry group which is distinct from, but closely related to the Lorentz group, and fixes the clock of the source for all observers. The new wave equation contains an additional term (dissipative), which arises instantaneously with acceleration. This shows that the origin of radiation reaction is not the action of a "charge" on itself but arises from inertial resistance to changes in motion. This dissipative term is equivalent to an effective mass so that classical radiation has both a massless and a massive part. Hence, at the local level the theory is one of particles and fields but there is no self-energy divergence (nor any of the other problems). We also show that, for any closed system of particles, there is a global inertial frame and unique (...
Karpowicz, Anna
The considered model will be formulated as related to "the fishing problem" even if the other applications of it are much more obvious. The angler goes fishing. He uses various techniques and he has at most two fishing rods. He buys a fishing ticket for a fixed time. The fishes are caught with the use of different methods according to the renewal processes. The fishes' value and the inter arrival times are given by the sequences of independent, identically distributed (i.i.d.) random variables with the known distribution functions. It forms the marked renewal--reward process. The angler's measure of satisfaction is given by the difference between the utility function, depending on the value of the fishes caught, and the cost function connected with the time of fishing. In this way, the angler's relative opinion about the methods of fishing is modelled. The angler's aim is to have as much satisfaction as possible and additionally he has to leave the lake before a fixed moment. Therefore his goal is to find two...
Postdatism -- a perinatal problem?
Chhabra, S; Sood, S
It has been traditionally accepted that maternal and fetal complications are at their lowest levels 37-42 weeks into gestation. 20% of pregnancies completed after 42 weeks gestation are thought to be affected by the postmaturity syndrome of uteroplacental insufficiency resulting in oligohydramnios, meconium passage, loss of fetal subcutaneous tissue, fetal asphyxia, and fetal death. Some workers, however, have also found that pregnancies completed between 40 and 42 weeks carry significant risk. The authors explored this question in a case-control study of 464 women seen at the Mahatma Gandhi Institute of Medical Sciences in Maharashtra, India. The cases of postdatism occurred in the absence of any other medical or obstetric problem. The operative delivery rate increased significantly among these patients compared to deliveries between 39 and 40 weeks. There was neither significant asphyxia nor perinatal loss in term completed normal patients. Asphyxia and perinatal mortality did, however, occur with postdatism. The authors note the likely role of oligohydramnios combined with placental dysfunction.
Bronchiectasis: still a problem
Institute of Scientific and Technical Information of China (English)
Wang Zengli
Objective The purpose of this descriptive review was to delineate the current knowledge of bronchiectasis in terms of prevalence,burden of disease,pathophysiology,and management.Data sources The National Library of Medicines MEDLINE and PubMed database (2005-2013) were used to conduct a search using the keyword term "bronchiectasis".The references for articles being considered for inclusion were searched from additional sources such as conference proceedings.Study selection Criteria for inclusion of articles included data outlining epidemiology,pathogenesis,diagnosis,and evidence-based guidelines for management of bronchiectasis.In assessing the quality of the articles,factors such as size of the population studied,clinical setting of the study,and whether or not the studies were prospective or retrospective were taken into consideration.Review articles were also included in our data collection.Results Despite many advances in modem medicine,bronchiectasis still remains a significant public health problem in developed countries and the developing world.It carries a significant burden worldwide in terms of morbidity and mortality,as well as financially to the affected population.In addition,bronchiectasis may associate with chronic airflow obstruction,regardless of smoking status.Conclusions Bronchiectasis is a debilitating illness responsible for significant morbidity with a poor health-related quality of life.The condition has a substantial socioeconomic cost because both primary and secondary healthcare resources are frequently used and periods of sick leave are common.
Smoothing of mixed complementarity problems
Energy Technology Data Exchange (ETDEWEB)
Gabriel, S.A.; More, J.J. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.
The authors introduce a smoothing approach to the mixed complementarity problem, and study the limiting behavior of a path defined by approximate minimizers of a nonlinear least squares problem. The main result guarantees that, under a mild regularity condition, limit points of the iterates are solutions to the mixed complementarity problem. The analysis is applicable to a wide variety of algorithms suitable for large-scale mixed complementarity problems.
Heuristic methods for messenger problem
Kobzareva, Maria
This work describes static and dynamic problems with one messenger or multiple number of messengers and suggests a possibility of solving such problems with modified heuristic methods. To solve messenger problem, modified nearest neighbor heuristic, modified insertion heuristic and modified exchange heuristic are used. The main contribution of this work are applications, developed in MS Excel, programmed with Visual Basic for Application, that can solve static and dynamic problems with one me...
Dimensions of problem based learning
DEFF Research Database (Denmark)
Nielsen, Jørgen Lerche; Andreasen, Lars Birch
The article contributes to the literature on problem based learning and problem-oriented project work, building on and reflecting the experiences of the authors through decades of work with problem-oriented project pedagogy. The article explores different dimensions of problem based learning...... and Learning (MIL). We discuss changes in the roles of the teachers as supervisors within this learning environment, and we explore the involvement of students as active participants and co-designers of how course and project activities unfold....
The Split Variational Inequality Problem
Censor, Yair; Reich, Simeon
We propose a new variational problem which we call the Split Variational Inequality Problem (SVIP). It entails finding a solution of one Variational Inequality Problem (VIP), the image of which under a given bounded linear transformation is a solution of another VIP. We construct iterative algorithms that solve such problems, under reasonable conditions, in Hilbert space and then discuss special cases, some of which are new even in Euclidean space.
About an optimal visiting problem
Bagagiolo, Fabio; Benetton, Michela
In this paper we are concerned with the optimal control problem consisting in minimizing the time for reaching (visiting) a fixed number of target sets, in particular more than one target. Such a problem is of course reminiscent of the famous "Traveling Salesman Problem" and brings all its computational diculties. Our aim is to apply the dynamic programming technique in order to characterize the value function of the problem as the unique viscosity solution of a suitable Hamilton-Jacobi equat...
Wild, Walter J.
Discusses the simplest three-body problem, known as Euler's problem. The article, intended for students in the undergraduate mathematics and physics curricula, shows how the complex equations for a specific three-body problem can be solved on a small calculator. (HM)
Problem children or harassed childhood?
DEFF Research Database (Denmark)
Warming, Hanne
instition as stressed andnoisy, and thus it is the children they try to change (re-socialize) to solve the problems. The paper concludes that the discoruses tend to individualize structural problems with the result that a large group of children are identified as problem children rather than given better...
Solving complex fisheries management problems
DEFF Research Database (Denmark)
Petter Johnsen, Jahn; Eliasen, Søren Qvist
A crucial issue for the new EU common fisheries policy is how to solve the discard problem. Through a study of the institutional set up and the arrangements for solving the discard problem in Denmark, the Faroe Islands, Iceland and Norway, the article identifies the discard problem as related...
International Nuclear Information System (INIS)
The report contains data on operational and emergency staff of the Chernobyl nuclear power plant who were exposed to radiation as a consequence of the reactor accident, the size of the doses received and consequences for health. 203 persons were found to have acute radiation sickness. Of the 22 patients suffering from an extremely severe degree of acute radiation sickness, 19 died. Of the 23 patients with severe bone marrow syndrome, 7 died. For the majority of patients, clinical recovery occurred toward the end of the second month following the accident. The main harmful factor for all victims was the relatively uniform gamma- and beta-radiation effect in a dosage exceeding 1 Gy and, in the case of 35 people exceeding 4 Gy. Radiation damage to wide areas of the skin was one of the main factors contributing to the overall severe condition of the patients, and was a determining factor in the main fatal complications. A preliminary evaluation of the use of some biochemical and immunological tests in the event of accidental exposure to radiation and the methods of treatment and preliminary assessment of their effectiveness are presented. Another part of the report contains data on the doses from radiation exposure to the population of the town of Pripyat' until the time of evacuation and to the population in the 30 km zone around Chernobyl' nuclear power plant and radiation consequences of the accident for the population of different regions in the European part of the USSR, especially the problems related to the contamination of food products. The last part of the report gives some data on the organization of medical examinations of the population from the region around the Chernobyl' plant and on the long-term programmes for the medical and biological monitoring of the population and personnel
International Nuclear Information System (INIS)
The resonant frequencies of solar acoustic-gravity waves are considered as probes of the sun's internal structure and dynamics. A perturbation method for calculating the effects of slow rotation and weak magnetic fields on p-mode frequencies is presented. Distortion of the equilibrium state of the star is taken into account. The method is applied to various hypothetical magnetic field geometries and rotation laws. Asymptotic estimates are developed and compared with the numerical results. The combined effect of rotation and magnetic fields is discussed. Current observations are reviewed in the light of the present results. A simple model is used to investigate the frequencies of high-degree acoustic modes which may be confined to the solar chromosphere. Such modes may be detected in observations from space. It is argued that they could provide a means of determining the mean sound speed in the chromosphere and the location of the transition zone between chromosphere and corona. It has been suggested that the sun could contain in its core quark nuggets which may constitute the ''missing mass''. Solar oscillations provide an extra set of constraints that any solar model must satisfy. Non-standard solar models containing a central black hole and a quark nugget core are constructed. The effect on a combination of resonant p-frequencies sensitive to conditions in the core is calculated by an asymptotic method. A black hole tends to make agreement between theoretical eigenfrequencies and observation worse. A quark nugget core may improve the agreement but tends to make the neutrino problem more acute. (author)
DEFF Research Database (Denmark)
Foss, Kirsten; Foss, Nicolai
as a general approach to problem solving. We apply these Simonian ideas to organizational issues, specifically new organizational forms. Specifically, Simonian ideas allow us to develop a morphology of new organizational forms and to point to some design problems that characterize these forms.Keywords: Herbert...... Simon, problem-solving, new organizational forms. JEL Code: D23, D83......Two of Herbert Simon's best-known papers are "The Architecture of Complexity" and "The Structure of Ill-Structured Problems." We discuss the neglected links between these two papers, highlighting the role of decomposition in the context of problems on which constraints have been imposed...
About an Optimal Visiting Problem
Energy Technology Data Exchange (ETDEWEB)
Bagagiolo, Fabio, E-mail: firstname.lastname@example.com; Benetton, Michela [Unversita di Trento, Dipartimento di Matematica (Italy)
In this paper we are concerned with the optimal control problem consisting in minimizing the time for reaching (visiting) a fixed number of target sets, in particular more than one target. Such a problem is of course reminiscent of the famous 'Traveling Salesman Problem' and brings all its computational difficulties. Our aim is to apply the dynamic programming technique in order to characterize the value function of the problem as the unique viscosity solution of a suitable Hamilton-Jacobi equation. We introduce some 'external' variables, one per target, which keep in memory whether the corresponding target is already visited or not, and we transform the visiting problem in a suitable Mayer problem. This fact allows us to overcome the lacking of the Dynamic Programming Principle for the originary problem. The external variables evolve with a hysteresis law and the Hamilton-Jacobi equation turns out to be discontinuous.
Heuristics for Multidimensional Packing Problems
DEFF Research Database (Denmark)
Egeblad, Jens
In this thesis we consider solution methods for packing problems. Packing problems occur in many different situations both directly in the industry and as sub-problems of other problems. High-quality solutions for problems in the industrial sector may be able to reduce transportation and production......) and may be defined in any number of dimensions. Solution methods are based on theory from both computational geometry and operations research. The scientific contributions of this thesis are presented in the form of six papers and a section which introduces the many problem types and recent solution...... of items. The heuristic was developed in collaboration with an industrial partner and is now being used to solve hundreds of problems every day as part of their planning process. A simple heuristic for optimizing a placement of items with respect to balance and moment of inertia is presented in the fifth...
A taxonomy of inductive problems.
Kemp, Charles; Jern, Alan
Inductive inferences about objects, features, categories, and relations have been studied for many years, but there are few attempts to chart the range of inductive problems that humans are able to solve. We present a taxonomy of inductive problems that helps to clarify the relationships between familiar inductive problems such as generalization, categorization, and identification, and that introduces new inductive problems for psychological investigation. Our taxonomy is founded on the idea that semantic knowledge is organized into systems of objects, features, categories, and relations, and we attempt to characterize all of the inductive problems that can arise when these systems are partially observed. Recent studies have begun to address some of the new problems in our taxonomy, and future work should aim to develop unified theories of inductive reasoning that explain how people solve all of the problems in the taxonomy.
The Association between Attention Problems and Internalizing and Externalizing Problems: The Mediating Role of Peer Problems
Yip, Vania T.; Ang, Rebecca P.; Ooi, Yoon Phaik; Fung, Daniel S. S.; Mehrotra, Kala; Sung, Min; Lim, Choon Guan
Background: The high prevalence of attention problems in children warrants concern, as it is a risk factor for internalizing and externalizing problems. There lies a need to understand possible factors that may mediate this link so that interventions may be targeted to alleviate these mediators and interrupt the link between attention problems and…
Problem based teaching with other focuses than problem solving
Hansson, Per-Olof; Jansson, Per; Wihlborg, Elin
Problem based teaching has been on the agenda in higher education for at least the last twenty years and is embedded in professional educations often to prepare students for real life problem solving. However, in when higher education rather aim to provide deeper theoretical and reflective competences promoting the students capacities to address unpredictable challenges in different contexts, there might be other ways of applying and using problem based educational tools. In this paper we des...
The problem of time and the problem of quantum measurement
Singh, Tejinder P
Quantum theory depends on an external classical time, and there ought to exist an equivalent reformulation of the theory which does not depend on such a time. The demand for the existence of such a reformulation suggests that quantum theory is an approximation to a stochastic non-linear theory. The stochastic non-linearity provides a dynamical explanation for the collapse of the wave-function during a quantum measurement. Hence the problem of time and the measurement problem are related to each other: the search for a solution for the former problem naturally implies a solution for the latter problem.
Dimensions of problem based learning
DEFF Research Database (Denmark)
Nielsen, Jørgen Lerche; Andreasen, Lars Birch
The article contributes to the literature on problem based learning and problem-oriented project work, building on and reflecting the experiences of the authors through decades of work with problem-oriented project pedagogy. The article explores different dimensions of problem based learning such...... as the exploration of problems, the project method, online collaboration, and the dialogic nature of students' working together. A special attention is given to the historical development and theoretical roots of problem-oriented project work in Denmark. The case to be explored will be the Masters...... programme in ICT and Learning (MIL). We discuss changes in the roles of the teachers as supervisors within this learning environment, and we explore the involvement of students as active participants and co-designers of how course and project activities unfold....
Problem Prioritization in Usability Evaluation:
DEFF Research Database (Denmark)
Hertzum, Morten
Severity assessments enable prioritization of problems encountered during usability evaluations and thereby provide a device for guiding the utilization of design resources. However, designers' response to usability evaluations is also influenced by other factors, which may overshadow severity...... problems, emphasizing that to be effective severity assessments must be reliable, valid, and sufficiently persuasive to justify the cost of fixing problems. For the usability inspections, evaluators' ratings of problem impact and persistence were weakly correlated with the number of evaluators reporting...... a problem, indicating that different evaluators represent different subgroups of users or alternatively that evaluator-made severity assessments are of questionable reliability. To call designers' attention to the severe problems, the halving of the severity sum is proposed as a means of visualizing...
Abstract Cauchy problems three approaches
Melnikova, Irina V
Although the theory of well-posed Cauchy problems is reasonably understood, ill-posed problems-involved in a numerous mathematical models in physics, engineering, and finance- can be approached in a variety of ways. Historically, there have been three major strategies for dealing with such problems: semigroup, abstract distribution, and regularization methods. Semigroup and distribution methods restore well-posedness, in a modern weak sense. Regularization methods provide approximate solutions to ill-posed problems. Although these approaches were extensively developed over the last decades by many researchers, nowhere could one find a comprehensive treatment of all three approaches.Abstract Cauchy Problems: Three Approaches provides an innovative, self-contained account of these methods and, furthermore, demonstrates and studies some of the profound connections between them. The authors discuss the application of different methods not only to the Cauchy problem that is not well-posed in the classical sense, b...
Problem Solving and Complex Systems
Guinand, Frédéric
The observation and modeling of natural Complex Systems (CSs) like the human nervous system, the evolution or the weather, allows the definition of special abilities and models reusable to solve other problems. For instance, Genetic Algorithms or Ant Colony Optimizations are inspired from natural CSs to solve optimization problems. This paper proposes the use of ant-based systems to solve various problems with a non assessing approach. This means that solutions to some problem are not evaluated. They appear as resultant structures from the activity of the system. Problems are modeled with graphs and such structures are observed directly on these graphs. Problems of Multiple Sequences Alignment and Natural Language Processing are addressed with this approach.
Inverse problem in hydrogeology
Carrera, Jesús; Alcolea, Andrés; Medina, Agustín; Hidalgo, Juan; Slooten, Luit J.
The state of the groundwater inverse problem is synthesized. Emphasis is placed on aquifer characterization, where modelers have to deal with conceptual model uncertainty (notably spatial and temporal variability), scale dependence, many types of unknown parameters (transmissivity, recharge, boundary conditions, etc.), nonlinearity, and often low sensitivity of state variables (typically heads and concentrations) to aquifer properties. Because of these difficulties, calibration cannot be separated from the modeling process, as it is sometimes done in other fields. Instead, it should be viewed as one step in the process of understanding aquifer behavior. In fact, it is shown that actual parameter estimation methods do not differ from each other in the essence, though they may differ in the computational details. It is argued that there is ample room for improvement in groundwater inversion: development of user-friendly codes, accommodation of variability through geostatistics, incorporation of geological information and different types of data (temperature, occurrence and concentration of isotopes, age, etc.), proper accounting of uncertainty, etc. Despite this, even with existing codes, automatic calibration facilitates enormously the task of modeling. Therefore, it is contended that its use should become standard practice. L'état du problème inverse des eaux souterraines est synthétisé. L'accent est placé sur la caractérisation de l'aquifère, où les modélisateurs doivent jouer avec l'incertitude des modèles conceptuels (notamment la variabilité spatiale et temporelle), les facteurs d'échelle, plusieurs inconnues sur différents paramètres (transmissivité, recharge, conditions aux limites, etc.), la non linéarité, et souvent la sensibilité de plusieurs variables d'état (charges hydrauliques, concentrations) des propriétés de l'aquifère. A cause de ces difficultés, le calibrage ne peut êtreséparé du processus de modélisation, comme c'est le
Active Learning for Matching Problems
Charlin, Laurent; Zemel, Rich; Boutilier, Craig
Effective learning of user preferences is critical to easing user burden in various types of matching problems. Equally important is active query selection to further reduce the amount of preference information users must provide. We address the problem of active learning of user preferences for matching problems, introducing a novel method for determining probabilistic matchings, and developing several new active learning strategies that are sensitive to the specific matching objective. Expe...
Solving Public Transit Scheduling Problems
Mesquita, Marta; Moz, Margarida; Paias, Ana; Paixão, José; Pato, Margarida Vaz; Respício, Ana
Operational planning within public transit companies has been extensively tackled but still remains a challenging area for operations research models and techniques. This phase of the planning process comprises vehicle scheduling, crew scheduling and rostering problems. In this paper, a new integer mathematical formulation to describe the integrated vehicle-crew-rostering problem is presented. The method proposed to solve this multi-objective problem is a sequential algorithm considered withi...
Mathematical problems for chemistry students
Pota, Gyorgy
Mathematical Problems for Chemistry Students has been compiled and written (a) to help chemistry students in their mathematical studies by providing them with mathematical problems really occurring in chemistry (b) to help practising chemists to activate their applied mathematical skills and (c) to introduce students and specialists of the chemistry-related fields (physicists, mathematicians, biologists, etc.) into the world of the chemical applications. Some problems of the collection are mathematical reformulations of those in the standard textbooks of chemistry, other
The underinvestment problem under conglomeration
Directory of Open Access Journals (Sweden)
Jacques A. Schnabel
Full Text Available This theoretical paper explores whether the underinvestment problem is aggravated or ameliorated by the formation of a pure conglomerate. It establishes that the answer depends critically on the volatility of corporate assets. If volatility is low, conglomeration ameliorates the underinvestment problem, whereas if volatility is high, conglomeration aggravates the underinvestment problem. These analytical results are then invoked as a potential explanation for the ambiguous conclusions of empirical studies that delve into the existence of a conglomerate discount.
Mathematical problems for chemistry students
Pota, Gyorgy
Mathematical Problems for Chemistry Students has been compiled and written (a) to help chemistrystudents in their mathematical studies by providing them with mathematical problems really occurring in chemistry (b) to help practising chemists to activate their applied mathematical skills and (c) to introduce students and specialistsof the chemistry-related fields (physicists, mathematicians, biologists, etc.) intothe world of the chemical applications.Some problems of the collection are mathematical reformulations of those in the standard textbooks of chemistry, others we
Psychological distress and problem drinking
Mentzakis, Emmanouil; Roberts, Bayard; Suhrcke, Marc; McKee, Martin
We examine the influence of harmful alcohol use on mental health using a flexible two-step instrumental variables approach and household survey data from nine countries of the former Soviet Union. Using alcohol advertisements to instrument for alcohol, we show that problem drinking has a large detrimental effect on psychological distress, with problem drinkers exhibiting a 42% increase in the number of mental health problems reported and a 15% higher chance of reporting very poor mental healt...
Pet Problems at Home: Pet Problems in the Community.
Soltow, Willow
Discusses problems of pets in the community, examining the community's role related to disruptive pets and pet overpopulation. Also discusses pet problems at home, offering advice on selecting a pet, meeting a pet's needs, and disciplining pets. Includes a list of books, films/filmstrips, teaching materials, and various instructional strategies.…
Problem solving through recreational mathematics
Averbach, Bonnie
Historically, many of the most important mathematical concepts arose from problems that were recreational in origin. This book takes advantage of that fact, using recreational mathematics - problems, puzzles and games - to teach students how to think critically. Encouraging active participation rather than just observation, the book focuses less on mathematical results than on how these results can be applied to thinking about problems and solving them. Each chapter contains a diverse array of problems in such areas as logic, number and graph theory, two-player games of strategy, solitaire ga
Dynamics of Universe in Problems
Bolotin, Yu L; Ivashkevych, G I; Lemets, O A; Yerokhin, D A
We do not know books of problems on cosmology including its recent achievements. However we believe that such a book would be extremely useful for the youth poured in the last decade into that one of the most actively developing field of science. We suggest to cosmological community to create a joint collaboration "Dynamics of Universe in Problems". Now we propose first 500 problems as our contribution into that beginning. If our project will make an interest then it is needed to think how to organize technically the international collaboration in that direction. In any case we plan to update our "database" monthly, including 30-50 new problems every time.
Problem posing reflections and applications
Brown, Stephen I
As a result of the editors' collaborative teaching at Harvard in the late 1960s, they produced a ground-breaking work -- The Art Of Problem Posing -- which related problem posing strategies to the already popular activity of problem solving. It took the concept of problem posing and created strategies for engaging in that activity as a central theme in mathematics education. Based in part upon that work and also upon a number of articles by its authors, other members of the mathematics education community began to apply and expand upon their ideas. This collection of thirty readings is a tes
A Problem with Current Conceptions of Expert Problem Solving
Kuo, Eric; Gupta, Ayush; Elby, Andrew
Current conceptions of expert problem solving depict physical/conceptual reasoning and formal mathematical reasoning as separate steps: a good problem solver first translates a physical understanding into mathematics, then performs mathematical/symbolic manipulations, then interprets the mathematical solution physically. However, other research suggests that blending conceptual and symbolic reasoning during symbolic manipulations can reflect expertise. We explore the hypothesis that blending conceptual and symbolic reasoning (i) indicates problem-solving expertise more than adherence to "expert" problem-solving steps and (ii) is something some undergraduates do spontaneously, suggesting it's a feasible instructional target. Interviewed students were asked to (1) explain a particular equation and (2) solve a problem using that equation. In-depth analysis of two students, Alex and Pat, revealed a pattern of behavior. All 11 interviews were coded to investigate the generalizability of this pattern. Alex describe...
Problem Solving vis Soap Bubbles
Bader, William A.
Describes the use of a scientific phenomenon related to the concept of surface tension as an intriguing vehicle to direct attention to useful problem solving techniques. The need for a definite building process in attempts to solve mathematical problems is stressed. (EB)
Analysis of a Pendulum Problem
DEFF Research Database (Denmark)
Jantzen, Jan
The ball-balancer, or cart-ball system, demonstrates some basic concepts in control being nonlinear, multivariable, and non-minimum phase. It is basically an inverted pendulum problem, which is a much used benchmark problem. The objective here is to provide an analysis of the system, which can...
Non-Euclidean Visibility Problems
Indian Academy of Sciences (India)
Fernando Chamizo
We consider the analog of visibility problems in hyperbolic plane (represented by Poincaré half-plane model $\\mathbb{H}$), replacing the standard lattice $\\mathbb{Z} × \\mathbb{Z}$ by the orbit = under the full modular group $SL_2(\\mathbb{Z})$. We prove a visibility criterion and study orchard problem and the cardinality of visible points in large circles.
Problems diagnosis in diesel engines
Energy Technology Data Exchange (ETDEWEB)
Leugner, L.
Diagnosis of engine problems in diesel engines used in Western Canadian coal mines is discussed. Areas to which attention must be paid include the air cleaners, turbocharger, engine compression and the fuel system. Exhaust smoke should be analysed to help diagnose combustion related problems.
Vibrations and Stability: Solved Problems
DEFF Research Database (Denmark)
Thomsen, Jon Juel
Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003.......Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003....
Some Results behind Dividend Problems
Institute of Scientific and Technical Information of China (English)
Ming Zhou; Li Wei; Jun-yi Guo
We consider the basic dividend problem of the compound Poisson model with constant barrier strategy. Some results concealed behind the dividend problem are made explicit in the present work. Different methods and some of which are firstly given in this paper. All these results presented certain direct relationship between some important actuary variables in classical risk theory is also revealed.
Geothermal Energy: Prospects and Problems
Ritter, William W.
An examination of geothermal energy as a means of increasing the United States power resources with minimal pollution problems. Developed and planned geothermal-electric power installations around the world, capacities, installation dates, etc., are reviewed. Environmental impact, problems, etc. are discussed. (LK)
Combinatorial reasoning to solve problems
Coenen, Tom; Hof, Frits; Verhoef, Nellie
This study reports combinatorial reasoning to solve problems. We observed the mathematical thinking of students aged 14-16. We study the variation of the students' solution strategies in the context of emergent modelling. The results show that the students are tempted to begin the problem solving pr
DEFF Research Database (Denmark)
Olsen, Poul Bitsch; Pedersen, Nils Kaare
This book is meant to support problem-oriented learning activities. Problem-orientation concerns the reasoning about lack of knowledge, while project work includes the ethnomethods that are practiced when collectives produce scientific knowledge. This book reflects particular methods related...
Students' Problem Solving and Justification
Glass, Barbara; Maher, Carolyn A.
This paper reports on methods of students' justifications of their solution to a problem in the area of combinatorics. From the analysis of the problem solving of 150 students in a variety of settings from high-school to graduate study, four major forms of reasoning evolved: (1) Justification by Cases, (2) Inductive Argument, (3) Elimination…
Promote Problem-Solving Discourse
Bostic, Jonathan; Jacobbe, Tim
Fourteen fifth-grade students gather at the front of the classroom as their summer school instructor introduces Jonathan Bostic as the mathematics teacher for the week. Before examining any math problems, Bostic sits at eye level with the students and informs them that they will solve problems over the next four days by working individually as…
Solving the drift control problem
Directory of Open Access Journals (Sweden)
Melda Ormeci Matoglu
Full Text Available We model the problem of managing capacity in a build-to-order environment as a Brownian drift control problem. We formulate a structured linear program that models a practical discretization of the problem and exploit a strong relationship between relative value functions and dual solutions to develop a functional lower bound for the continuous problem from a dual solution to the discrete problem. Refining the discretization proves a functional strong duality for the continuous problem. The linear programming formulation is so badly scaled, however, that solving it is beyond the capabilities of standard solvers. By demonstrating the equivalence between strongly feasible bases and deterministic unichain policies, we combinatorialize the pivoting process and by exploiting the relationship between dual solutions and relative value functions, develop a mechanism for solving the LP without ever computing its coefficients. Finally, we exploit the relationship between relative value functions and dual solutions to develop a scheme analogous to column generation for refining the discretization so as to drive the gap between the discrete approximation and the continuous problem to zero quickly while keeping the LP small. Computational studies show our scheme is much faster than simply solving a regular discretization of the problem both in terms of finding a policy with a low average cost and in terms of providing a lower bound on the optimal average cost.
Reactor physics problems on HCPWR
International Nuclear Information System (INIS)
Reactor physics problems on high conversion pressurized water reactors (HCPWRs) are discussed. Described in this report are outline of the HCPWR, expected accuracy for the various reactor physical qualities, and method for K-effective calculation in the resonance energy area. And requested further research problems are shown. The target value of the conversion ratio are also discussed. (author)
Subspace Methods for Eigenvalue Problems
Hochstenbach, Michiel Erik
This thesis treats a number of aspects of subspace methods for various eigenvalue problems. Vibrations and their corresponding eigenvalues (or frequencies) arise in science, engineering, and daily life. Matrix eigenvalue problems come from a large number of areas, such as chemistry, mechanics, dyn
Learning Impasses in Problem Solving
Hodgson, J. P. E.
Problem Solving systems customarily use backtracking to deal with obstacles that they encounter in the course of trying to solve a problem. This paper outlines an approach in which the possible obstacles are investigated prior to the search for a solution. This provides a solution strategy that avoids backtracking.
Sinopec Tests Find No Problems
Institute of Scientific and Technical Information of China (English)
@@ Sinopec gas defended the quality of its liquefied petroleum gas(LPG)by announcing the results of independent tests in early February,following allegations by drivers that their vehicles had problems after filling their tanks at Sinopec petrol stations.Its first media briefing over the suspected engine-stalling problem of its product,Sinopec(Hong Kong)Petrol Filling Station Co.
Difficulties in Genetics Problem Solving.
Tolman, Richard R.
Examined problem-solving strategies of 30 high school students as they solved genetics problems. Proposes a new sequence of teaching genetics based on results: meiosis, sex chromosomes, sex determination, sex-linked traits, monohybrid and dihybrid crosses (humans), codominance (humans), and Mendel's pea experiments. (JN)
The problem of compatible representatives
Knuth, Donald E
The purpose of this note is to attach a name to a natural class of combinatorial problems and to point out that this class includes many important special cases. We also show that a simple problem of placing nonoverlapping labels on a rectangular map is NP-complete.
Methods of solving nonstandard problems
Grigorieva, Ellina
This book, written by an accomplished female mathematician, is the second to explore nonstandard mathematical problems – those that are not directly solved by standard mathematical methods but instead rely on insight and the synthesis of a variety of mathematical ideas. It promotes mental activity as well as greater mathematical skills, and is an ideal resource for successful preparation for the mathematics Olympiad. Numerous strategies and techniques are presented that can be used to solve intriguing and challenging problems of the type often found in competitions. The author uses a friendly, non-intimidating approach to emphasize connections between different fields of mathematics and often proposes several different ways to attack the same problem. Topics covered include functions and their properties, polynomials, trigonometric and transcendental equations and inequalities, optimization, differential equations, nonlinear systems, and word problems. Over 360 problems are included with hints, ...
Statistical perspectives on inverse problems
DEFF Research Database (Denmark)
Andersen, Kim Emil
Inverse problems arise in many scientific disciplines and pertain to situations where inference is to be made about a particular phenomenon from indirect measurements. A typical example, arising in diffusion tomography, is the inverse boundary value problem for non-invasive reconstruction...... of the interior of an object from electrical boundary measurements. One part of this thesis concerns statistical approaches for solving, possibly non-linear, inverse problems. Thus inverse problems are recasted in a form suitable for statistical inference. In particular, a Bayesian approach for regularisation...... is obtained by assuming that the a priori beliefs about the solution before having observed any data can be described by a prior distribution. The solution to the statistical inverse problem is then given by the posterior distribution obtained by Bayes' formula. Hence the solution of an ill-posed inverse...
Multiscale Modelling and Inverse Problems
Nolen, J; Stuart, A M
The need to blend observational data and mathematical models arises in many applications and leads naturally to inverse problems. Parameters appearing in the model, such as constitutive tensors, initial conditions, boundary conditions, and forcing can be estimated on the basis of observed data. The resulting inverse problems are often ill-posed and some form of regularization is required. These notes discuss parameter estimation in situations where the unknown parameters vary across multiple scales. We illustrate the main ideas using a simple model for groundwater flow. We will highlight various approaches to regularization for inverse problems, including Tikhonov and Bayesian methods. We illustrate three ideas that arise when considering inverse problems in the multiscale context. The first idea is that the choice of space or set in which to seek the solution to the inverse problem is intimately related to whether a homogenized or full multiscale solution is required. This is a choice of regularization. The ...
Math word problems for dummies
Sterling, Mary Jane
Covers percentages, probability, proportions, and moreGet a grip on all types of word problems by applying them to real lifeAre you mystified by math word problems? This easy-to-understand guide shows you how to conquer these tricky questions with a step-by-step plan for finding the right solution each and every time, no matter the kind or level of problem. From learning math lingo and performing operations to calculating formulas and writing equations, you''ll get all the skills you need to succeed!Discover how to: * Translate word problems into plain English* Brush up on basic math skills* Plug in the right operation or formula* Tackle algebraic and geometric problems* Check your answers to see if they work
International Nuclear Information System (INIS)
The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis and searching for periodic orbits and resonances. We apply the results to some interesting problems of celestial mechanics. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications. (review article)
Spreadsheet modelling for solving combinatorial problems: The vendor selection problem
Ipsilandis, Pandelis G
Spreadsheets have grown up and became very powerful and easy to use tools in applying analytical techniques for solving business problems. Operations managers, production managers, planners and schedulers can work with them in developing solid and practical Do-It-Yourself Decision Support Systems. Small and Medium size organizations, can apply OR methodologies without the presence of specialized software and trained personnel, which in many cases cannot afford anyway. This paper examines an efficient approach in solving combinatorial programming problems with the use of spreadsheets. A practical application, which demonstrates the approach, concerns the development of a spreadsheet-based DSS for the Multi Item Procurement Problem with Fixed Vendor Cost. The DSS has been build using exclusively standard spreadsheet feature and can solve real problems of substantial size. The benefits and limitations of the approach are also discussed.
Problem solving stages in the five square problem.
Fedor, Anna; Szathmáry, Eörs; Öllinger, Michael
According to the restructuring hypothesis, insight problem solving typically progresses through consecutive stages of search, impasse, insight, and search again for someone, who solves the task. The order of these stages was determined through self-reports of problem solvers and has never been verified behaviorally. We asked whether individual analysis of problem solving attempts of participants revealed the same order of problem solving stages as defined by the theory and whether their subjective feelings corresponded to the problem solving stages they were in. Our participants tried to solve the Five-Square problem in an online task, while we recorded the time and trajectory of their stick movements. After the task they were asked about their feelings related to insight and some of them also had the possibility of reporting impasse while working on the task. We found that the majority of participants did not follow the classic four-stage model of insight, but had more complex sequences of problem solving stages, with search and impasse recurring several times. This means that the classic four-stage model is not sufficient to describe variability on the individual level. We revised the classic model and we provide a new model that can generate all sequences found. Solvers reported insight more often than non-solvers and non-solvers reported impasse more often than solvers, as expected; but participants did not report impasse more often during behaviorally defined impasse stages than during other stages. This shows that impasse reports might be unreliable indicators of impasse. Our study highlights the importance of individual analysis of problem solving behavior to verify insight theory.
Ruin problems and tail asymptotics
DEFF Research Database (Denmark)
Rønn-Nielsen, Anders
The thesis Ruin Problems and Tail Asymptotics provides results on ruin problems for several classes of Markov processes. For a class of diffusion processes with jumps an explicit expression for the joint Laplace transform of the first passage time and the corresponding undershoot is derived...... by an underlying Harris recurrent Markov process some asymptotic results for the ruin probability are derived. Finally, a paper, which is separate in content from the rest of the thesis, treats a RESTART problem in the situation, where failures occur with decreasing intensity....
Problems of multiphase fluid filtration
Konovalov, AN
This book deals with a spectrum of problems related to the mathematical modeling of multiphase filtration. Emphasis is placed on an inseparable triad: model - algorithm - computer code. An analysis of new and traditional filtration problems from the point of view of both their numerical implementation and the reproduction of one or another technological characteristics of the processes under consideration is given. The basic principles which underlie the construction of efficient numerical methods taking into account the filtration problems are discussed: non-evolutionary nature, degeneration,
Problem Based Learning and sustainability
DEFF Research Database (Denmark)
Pizzol, Massimo; Løkke, Søren; Schmidt, Jannick Højrup
Problem-Based Learning (PBL) is a style of active learning based on problem solving. PBL aims at providing university students with flexible knowledge, capacity to self-learning, and skills in problem solving and collaboration. In this context, the present study explores the advantages...... University (AAU), Denmark, and focuses on the teaching of Life Cycle Assessment as a method for sustainability assessment. The objective is providing recommendations for future LCA teaching and learning. PBL activites performed at AAU were evaluated critically to detemine to what extent they addressed...
Parameter estimation and inverse problems
Aster, Richard C; Thurber, Clifford H
Parameter Estimation and Inverse Problems, 2e provides geoscience students and professionals with answers to common questions like how one can derive a physical model from a finite set of observations containing errors, and how one may determine the quality of such a model. This book takes on these fundamental and challenging problems, introducing students and professionals to the broad range of approaches that lie in the realm of inverse theory. The authors present both the underlying theory and practical algorithms for solving inverse problems. The authors' treatment is approp
Beliefs about Drinking Problem Causation
Directory of Open Access Journals (Sweden)
Susan Bullers
Full Text Available Research has found that "internal" or personal attributions about the causes of problem drinking increase the likelihood of seeking treatment and treatment efficacy, while "external" attributions, such as environmental, social or cultural causations, may hinder treatment efforts. Results of survey data from a sample of 152 US college students found three main causation belief factors, which were differentially associated with age, heavy drinking, protestant religion, and exposure to problem drinkers. The "Social Cause" factor was the most strongly endorsed belief suggesting external, but surmountable attributions for problem drinking. Implications of attributions for treatment efficacy are discussed.
Imbalance problem in community detection
Sun, Peng Gang
Community detection gives us a simple way to understand complex networks' structures. However, there is an imbalance problem in community detection. This paper first introduces the imbalance problem and then proposes a new measure to alleviate the imbalance problem. In addition, we study two variants of the measure and further analyze the resolution scale of community detection. Finally, we compare our approach with some state of the art methods on random networks as well as real-world networks for community detection. Both the theoretical analysis and the experimental results show that our approach achieves better performance for community detection. We also find that our approach tends to separate densely connected subgroups preferentially.
Parameter estimation and inverse problems
Aster, Richard C; Thurber, Clifford H
Parameter Estimation and Inverse Problems primarily serves as a textbook for advanced undergraduate and introductory graduate courses. Class notes have been developed and reside on the World Wide Web for faciliting use and feedback by teaching colleagues. The authors'' treatment promotes an understanding of fundamental and practical issus associated with parameter fitting and inverse problems including basic theory of inverse problems, statistical issues, computational issues, and an understanding of how to analyze the success and limitations of solutions to these probles. The text is also a practical resource for general students and professional researchers, where techniques and concepts can be readily picked up on a chapter-by-chapter basis.Parameter Estimation and Inverse Problems is structured around a course at New Mexico Tech and is designed to be accessible to typical graduate students in the physical sciences who may not have an extensive mathematical background. It is accompanied by a Web site that...
Musielak, Z E
The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis, search for periodic orbits and resonances, and application of the results to some interesting astronomical and space dynamical settings. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications.
COPD and other health problems
... this page: //medlineplus.gov/ency/patientinstructions/000701.htm COPD and other health problems To use the sharing ... diabetes, and high blood pressure. Staying Healthy With COPD Work closely with your doctor to keep COPD ...
Uncapacitated facility location problems: contributions
Directory of Open Access Journals (Sweden)
Galvão Roberto Diéguez
Full Text Available The objective of the present paper is to review my personal contributions in the field of uncapacitated facility location problems. These contributions took place throughout my academic career, from the time I was a Ph.D. student at Imperial College to the present day. They cover approximately 30 years, from 1973 to 2003; they address: algorithms developed for the p-median problem and for a general formulation of uncapacitated location problems; the study of dynamic location models; covering and hierarchical location problems; queuing-based probabilistic location models. The contributions encompass theoretical developments, computational algorithms and practical applications. All work took place in an academic environment, with the invaluable collaboration of colleagues (both in Brazil and abroad and research students at COPPE. Each section in the paper is dedicated to a topic that involves a personal contribution. Every one of them is placed within the context of the existing literature.
Fuel cells: Problems and prospects
Shukla, AK; Ramesh, KV; Kannan, AM
n recent years, fuel cell technology has advanced significantly. Field trials on certain types of fuel cells have shown promise for electrical use. This article reviews the electrochemistry, problems and prospects of fuel cell systems.
Integral equations and computation problems
International Nuclear Information System (INIS)
Volterra's Integral Equations and Fredholm's Integral Equations of the second kind are discussed. Computational problems are found in the derivations and the computations. The theorem of the solution of the Fredholm's Integral Equation is discussed in detail. (author)
Progressive problems higher grade physics
Kennedy, William
This book fully covers all three Units studied in Scotland's Higher Grade Physics course, providing a systematic array of problems (from the simplest to the most difficult) to lead variously abled pupils to examination success.
On Generalized Vector Equilibrium Problems
Institute of Scientific and Technical Information of China (English)
An-hua Wan; Jun-yi Fu; Wei-hua Mao
A new generalized vector equilibrium problem involving set-valued mappings and the proper quasi-concavity of set-valued mappings in topological vector spaces are introduced; its existence theorems and the convexity of the solution sets are established.
Eldercare at Home: Memory Problems
... parties. Use reminding strategies. When memory loss is obvious, try these reminding techniques: Encourage carrying a memo ... problem was due to a physical illness or depression, treatment is likely to improve memory. There are ...
Fodor, Jerry A.
Describes several different philosophies of mind with each philosophy's explanation of the mind-body problem. Philosophies discussed include dualism, materialism, functionalism, radical behaviorism, logical behaviorism and central-state identity. (DS)
Institute of Scientific and Technical Information of China (English)
Carsten Gr(a)ser; Ralf Kornhuber
In this review,we intend to clarify the underlying ideas and the relations between various multigrid methods ranging from subset decomposition,to projected subspace decomposition and truncated multigrid.In addition,we present a novel globally convergent inexact active set method which is closely related to truncated multigrid.The numerical properties of algorithms are carefully assessed by means of a degenerate problem and a problem with a complicated coincidence set.
Directory of Open Access Journals (Sweden)
Jesús Garcia Falset
Full Text Available In this paper, we establish some new existence, uniqueness and Ulam-Hyers stability theorems for coincidence problems for two single-valued mappings. The main results of this paper extend the results presented in {\\sc O. Mle\\c sni\\c te:} \\emph{Existence and Ulam-Hyers stability results for coincidence problems}, J. Nonlinear Sci.\\ Appl., \\textbf{6} (2013, 108--116. In the last section two examples of application of these results are also given.
Institute of Scientific and Technical Information of China (English)
The real price of Sept 11 for America is the economic decline. The reason is that America didn't deal well with the terrorists. So, Bush tax cuts and the deficit-financed wars in Iraq and Afghanistan made America heavily in debt. If America hadn't caused war in Iraq and Afghan in order to sol;ee the terrorist problem, things might be different now. That makes me think deeply how we should deal with problems.
Diabetes and Sexual and Urologic Problems
... Disease, and Other Dental Problems Diabetic Eye Disease Diabetes and Sexual and Urologic Problems Troublesome bladder symptoms ... early onset of these sexual and urologic problems. Diabetes and Sexual Problems Both men and women with ...
Conceptual approach to astronomical problems
Skvortsov, N. A.; Avvakumova, E. A.; Bryukhov, D. O.; Vovchenko, A. E.; Vol'nova, A. A.; Dluzhnevskaya, O. B.; Kaigorodov, P. V.; Kalinichenko, L. A.; Kniazev, A. Yu.; Kovaleva, D. A.; Malkov, O. Yu.; Pozanenko, A. S.; Stupnikov, S. A.
New technical capabilities have brought about the sweeping growth of the amount of data acquired by the astronomers from observations with different instruments in various parts of the electromagnetic spectrum. We consider conceptual approach to be a promising tool to efficiently deal with these data. It uses problem domain knowledge to formulate the tasks and develop problem-solving algorithms and data analysis methods in terms of domain concepts without reference to particular data sources, and thereby allows solving certain problems in general form. We demonstrate the benefits of conceptual approach by using it to solve problems related to search for secondary photometric standard candidates, determination of galaxy redshifts, creation of a binary and multiple star repository based on inhomogeneous databases, and classification of eclipsing binaries.We formulate and solve these problems over specifications of astronomical knowledge units such as photometric systems, astronomical objects, multiple stars, etc., and define them in terms of the corresponding problem domains independently of the existing data resources.
Stump problems in traumatic amputation.
Hirai, M; Tokuhiro, A; Takechi, H
Stump problems in amputations resulting from employment related injuries were investigated in 397 cases in the Chugoku and Shikoku districts of Japan between 1987 and 1991. Ninety-seven patients (24%) had stump problems which interfered the prosthetic fitting. Stump problems of the upper extremity were seen in about 9% (17 amputees), two thirds of which were skin troubles. Stump problems of the lower extremity were seen in about 37% (80 amputees). Certain complaints were associated with specific methods of amputation; abnormal keratosis in Syme's amputation, equinus deformity in Chopart's amputation, reduced muscle power in above the knee (A/K) amputation and joint dysfunction in below the knee (B/K) amputation. Adequate prosthetic fitting was achieved by the modification of the socket and alignment in almost all amputees with stump problems. In only two cases, Chopart's amputation required subsequent Syme's amputation due to equinus deformity with abnormal keratosis. In almost every case, stump problems are avoidable by means of surgeons' deliberate evaluation of the affected limb and adequate choice of the amputation level.
Aging and skilled problem solving.
Charness, N
Information-processing models of problem solving too often are based on restrictive age ranges. On the other hand, gerontologists have investigated few problem-solving tasks and have rarely generated explicit models. As this article demonstrates, both fields can benefit by closer collaboration. One major issue in gerontology is whether aging is associated with irreversible decrement or developmental plasticity. If both processes occur, then an appropriate strategy for investigating aging is to equate age groups for molar problem-solving performance and search for differences in the underlying components. This strategy was adopted to examine the relation of age and skill to problem solving in chess. Chess players were selected to vary widely in age and skill such that these variables were uncorrelated. Problem-solving and memory tasks were administered. Skill level was the only significant predictor for accuracy in both a choose-a-move task and a speeded end-game evaluation task. Age (negatively) and skill (positively) jointly determined performance in an unexpected recall task. Efficient chunking in recall was positively related to skill, though negatively related to age. Recognition confidence, though not accuracy, was negatively related to age. Thus despite age-related declines in encoding and retrieval of information, older players match the problem-solving performance of equivalently skilled younger players. Apparently, they can search the problem space more efficiently, as evidenced by taking less time to select an equally good move. Models of chess skill that stress that role of encoding efficiency, as indexed by chunking in recall, need to be modified to account for performance over the life span.
Ten Problems in Experimental Mathematics
Energy Technology Data Exchange (ETDEWEB)
Bailey, David H.; Borwein, Jonathan M.; Kapoor, Vishaal; Weisstein, Eric
This article was stimulated by the recent SIAM ''100 DigitChallenge'' of Nick Trefethen, beautifully described in a recent book. Indeed, these ten numeric challenge problems are also listed in a recent book by two of present authors, where they are followed by the ten symbolic/numeric challenge problems that are discussed in this article. Our intent was to present ten problems that are characteristic of the sorts of problems that commonly arise in ''experimental mathematics''. The challenge in each case is to obtain a high precision numeric evaluation of the quantity, and then, if possible, to obtain a symbolic answer, ideally one with proof. Our goal in this article is to provide solutions to these ten problems, and in the process present a concise account of how one combines symbolic and numeric computation, which may be termed ''hybrid computation'', in the process of mathematical discovery.
Problem Solvers: Problem--Area beyond the Formula
Dean, Chrystal
In this article, associate professor Chrystal Dean describes how teachers can challenge their upper elementary students' understanding of area beyond a memorized formula. Herein she describes an activity that will show students the "why" behind using A = l × w to solve rectangular area problems. The activity will help deepen…
Nuclear power engineering problems as the political and economical problems
International Nuclear Information System (INIS)
The political and economic aspects of nuclear power engineering status in the countries of the former USSR nowadays are considered. The factors, which lead to the nuclear power crisis, are analyzed. It is shown that the state monopoly for developing the problems of nuclear power engineering and NPP operation plays the main part. The ways for possible crisis overcoming are suggested
Sinus actuator solves emc problems; Sinussteller loest EMV-Probleme
Energy Technology Data Exchange (ETDEWEB)
Kammerer, Olaf [Systemtechnik LEBER GmbH und Co. KG, Schwaig (Germany)
The steep slope of the phase angle variation control tend to cause problems of electromagnetic compatibility. A sinus actuator controls the amplitude of the current continuously from 0 to 100 percent. It also has low power loss and requires no rectifier. (orig.)
The Problem of Assessing Problem Solving: Can Comparative Judgement Help?
Jones, Ian; Inglis, Matthew
School mathematics examination papers are typically dominated by short, structured items that fail to assess sustained reasoning or problem solving. A contributory factor to this situation is the need for student work to be marked reliably by a large number of markers of varied experience and competence. We report a study that tested an…
Linear and complex analysis problem
Nikolski, Nikolai
The 2-volume-book is an updated, reorganized and considerably enlarged version of the previous edition of the Research Problem Book in Analysis (LNM 1043), a collection familiar to many analysts, that has sparked off much research. This new edition, created in a joint effort by a large team of analysts, is, like its predecessor, a collection of unsolved problems of modern analysis designed as informally written mini-articles, each containing not only a statement of a problem but also historical and metho- dological comments, motivation, conjectures and discussion of possible connections, of plausible approaches as well as a list of references. There are now 342 of these mini- articles, almost twice as many as in the previous edition, despite the fact that a good deal of them have been solved!
Linear and complex analysis problem
Nikolski, Nikolai
The 2-volume book is an updated, reorganized and considerably enlarged version of the previous edition of the Research Problem Book in Analysis (LNM 1043), a collection familiar to many analysts, that has sparked off much research. This new edition, created in a joint effort by a large team of analysts, is, like its predecessor, a collection of unsolved problems of modern analysis designed as informally written mini-articles, each containing not only a statement of a problem but also historical and methodological comments, motivation, conjectures and discussion of possible connections, of plausible approaches as well as a list of references. There are now 342 of these mini- articles, almost twice as many as in the previous edition, despite the fact that a good deal of them have been solved!
Problem-oriented project studies
DEFF Research Database (Denmark)
Nielsen, Jørgen Lerche; Danielsen, Oluf
This contribution focuses on 'problem based learning' (however we prefer the notion of 'problem-oriented project studies') and the role of the teacher in such a context. The classic traditional role as an expert deciding the curriculum, providing lectures and seminars, giving assignments and...... marking papers / essays is complemented and in some way overruled by a new role as supervisor and facilitator for the group of students working with a research problem, they themselves have picked. However different dimensions of this new teacher role can be seen – from expert in an academic field (result-oriented...... focusing on how the final product demonstrates the students' 'correct' way to handle the academic aspects of the subject in mind) to a role more focusing on processes, methodological dimensions and stressing the importance of a reflexive approach. Some teachers may even tend to take on a role of a...
Problems of Collisional Stellar Dynamics
Heggie, Douglas C
The discovery of dynamical friction was Chandrasekhar's best known contribution to the theory of stellar dynamics, but his work ranged from the few-body problem to the limit of large N (in effect, galaxies). Much of this work was summarised in the text "Principles of Stellar Dynamics" (Chandrasekhar 1942, 1960), which ranges from a precise calculation of the time of relaxation, through a long analysis of galaxy models, to the behaviour of star clusters in tidal fields. The later edition also includes the work on dynamical friction and related issues. In this review we focus on progress in the collisional aspects of these problems, i.e. those where few-body interactions play a dominant role, and so we omit further discussion of galaxy dynamics. But we try to link Chandrasekhar's fundamental discoveries in collisional problems with the progress that has been made in the 50 years since the publication of the enlarged edition.
Problems in structural inorganic chemistry
Li, Wai-Kee; Mak, Thomas Chung Wai; Mak, Kendrew Kin Wah
This book consists of over 300 problems (and their solutions) in structural inorganic chemistry at the senior undergraduate and beginning graduate level. The topics covered comprise Atomic and Molecular Electronic States, Atomic Orbitals, Hybrid Orbitals, Molecular Symmetry, Molecular Geometry and Bonding, Crystal Field Theory, Molecular Orbital Theory, Vibrational Spectroscopy, and Crystal Structure. The central theme running through these topics is symmetry, molecular or crystalline. The problems collected in this volume originate in examination papers and take-home assignments that have been part of the teaching of the book's two senior authors' at The Chinese University of Hong Kong over the past four decades. The authors' courses include Chemical Bonding, Elementary Quantum Chemistry, Advanced Inorganic Chemistry, X-Ray Crystallography, etc. The problems have been tested by generations of students taking these courses.
Directory of Open Access Journals (Sweden)
Goran P, Šimić
Full Text Available The paper describes the self-directed problem-based learning system (PBL named Java PBL. The expert module is the kernel of Java PBL. It involves a specific domain model, a problem generator and a solution generator. The overall system architecture is represented in the paper. Java PBL can act as the stand-alone system, but it is also designed to provide support to learning management systems (LMSs. This is provided by a modular design of the system. An LMS can offer the declarative knowledge only. Java PBL offers the procedural knowledge and the progress of the learner programming skills. The free navigation, unlimited numbers of problems and recommendations represent the main pedagogical strategies and tactics implemented into the system.
Coping with persistent environmental problems
DEFF Research Database (Denmark)
Varjopuro, Riku; Andrulewicz, Eugeniusz; Brandt, Urs Steiner;
involved in the implementation are keys to improve understanding of the systemic delays. The improved understanding is necessary for the adaptive management of a persistent environmental problem. In addition to the state of the environment, the monitoring and analysis should be targeted also......ABSTRACT In this paper we focus on systemic delays in the Baltic Sea that cause the problem of eutrophication to persist. These problems are demonstrated in our study by addressing three types of delays: (1) decision delay: the time it takes for an idea or perceived need to be launched as a policy...... is to analyze these systemic delays and especially to discuss how the critical delays can be better addressed in marine protection policies by strengthening the adaptive capacity of marine protection. We conclude that the development of monitoring systems and reflexive, participatory analysis of dynamics...
Psychological Distress and Problem Drinking.
Mentzakis, Emmanouil; Roberts, Bayard; Suhrcke, Marc; McKee, Martin
We examine the influence of harmful alcohol use on mental health using a flexible two-step instrumental variables approach and household survey data from nine countries of the former Soviet Union. Using alcohol advertisements to instrument for alcohol, we show that problem drinking has a large detrimental effect on psychological distress, with problem drinkers exhibiting a 42% increase in the number of mental health problems reported and a 15% higher chance of reporting very poor mental health. Ignoring endogeneity leads to an underestimation of the damaging effect of excessive drinking. Findings suggest that more effective alcohol policies and treatment services in the former Soviet Union may have added benefits in terms of reducing poor mental health. PMID:25640167
Bernoulli Variational Problem and Beyond
Lorz, Alexander
The question of \\'cutting the tail\\' of the solution of an elliptic equation arises naturally in several contexts and leads to a singular perturbation problem under the form of a strong cut-off. We consider both the PDE with a drift and the symmetric case where a variational problem can be stated. It is known that, in both cases, the same critical scale arises for the size of the singular perturbation. More interesting is that in both cases another critical parameter (of order one) arises that decides when the limiting behaviour is non-degenerate. We study both theoretically and numerically the values of this critical parameter and, in the symmetric case, ask if the variational solution leads to the same value as for the maximal solution of the PDE. Finally we propose a weak formulation of the limiting Bernoulli problem which incorporates both Dirichlet and Neumann boundary condition. © 2013 Springer-Verlag Berlin Heidelberg.
Interference problems for nongeostationary satellites
Sollfrey, W.
The interference problems faced by nongeostationary satellites may be of major significance. A general discussion indicates the scope of the problems and describes several configurations of importance. Computer programs are described, which are employed by NASA/JPL and the U.S. Air Force Satellite Control Facility to provide interference-free scheduling of commands and data transmission. Satellite system mission planners are not concerned with the precise prediction of interference episodes, but rather with the expected total amount of interference, the mean and maximum duration of events, and the mean spacing between episodes. The procedures in the theory of probability developed by the author which permit calculation of such quantities are described and applied to several real cases. It may be anticipated that the problems will become steadily worse in the future as more and more data transmissions attempt to occupy the same frequency band.
Psychosocial Problems during Infertility Treatment
Directory of Open Access Journals (Sweden)
Nurcan Kirca
Full Text Available Infertility is a complex situation crisis which is often psychologically-threatening and emotionally stressful for both partners as well as economically expensive and causes physical pain due to the operations performed for diagnosis and treatment purposes. Infertility has physical, psychological, social, emotional and financial impacts. Infertile couples are under a great social pressure, and need to conceal the problem as it is exceptionally private for them. Infertile individuals are destitute of support when they do not share their pregnancy problems with their families and relatives. Couples define their infertility experience as the most stressful experience of their lives.
Interactive problem solving using LOGO
Boecker, Heinz-Dieter; Fischer, Gerhard
This book is unique in that its stress is not on the mastery of a programming language, but on the importance and value of interactive problem solving. The authors focus on several specific interest worlds: mathematics, computer science, artificial intelligence, linguistics, and games; however, their approach can serve as a model that may be applied easily to other fields as well. Those who are interested in symbolic computing will find that Interactive Problem Solving Using LOGO provides a gentle introduction from which one may move on to other, more advanced computational frameworks or more
Tackling Problems in Reading Efficiency
Institute of Scientific and Technical Information of China (English)
Reading is a complex,communicative process,which involves both linguistic and cognitive knowledge.The lack of either part will cause inefficiency.So,this paper deals with problems in reading efficiency in English study for college students in China.It analyzes the problems with regard to linguistic knowledge and cognitive schemata,emphasizing that solid linguistic foundation is the premise,and active communication skills are catalytic promoters while formal scientific training is necessary,and proposes some countermeasures on how to en hance the college student's reading efficiency.
Inverse Problems in Structural Mechanics
Li, Jing
This dissertation deals with the solution of three inverse problems in structural mechanics. The first one is load updating for finite element models (FEMs). A least squares fitting is used to identify the load parameters. The basic studies are made for geometrically linear and nonlinear FEMs of beams or frames by using a four-noded curved beam element, which, for a given precision, may significantly solve the ill-posed problem by reducing the overall number of degrees of freedom (DOF) of t...
Unsolved problems in number theory
Guy, Richard K
Unsolved Problems in Number Theory contains discussions of hundreds of open questions, organized into 185 different topics. They represent numerous aspects of number theory and are organized into six categories: prime numbers, divisibility, additive number theory, Diophantine equations, sequences of integers, and miscellaneous. To prevent repetition of earlier efforts or duplication of previously known results, an extensive and up-to-date collection of references follows each problem. In the second edition, not only extensive new material has been added, but corrections and additions have been included throughout the book.
Problems in astrophysical radiation hydrodynamics
Energy Technology Data Exchange (ETDEWEB)
Castor, J.I.
The basic equations of radiation hydrodynamics are discussed in the regime that the radiation is dynamically as well as thermally important. Particular attention is paid to the question of what constitutes an acceptable approximate non-relativistic system of dynamical equations for matter and radiation in this regime. Further discussion is devoted to two classes of application of these ideas. The first class consists of problems dominated by line radiation, which is sensitive to the velocity field through the Doppler effect. The second class is of problems in which the advection of radiation by moving matter dominates radiation diffusion.
Problem-Oriented Project Studies
DEFF Research Database (Denmark)
Nielsen, Jørgen Lerche; Danielsen, Oluf
Focus is on problem-based learning in a networked learning context with focus on the use of technologies in the communicative processes among the participants. Especially, the role of the teacher in such a context is analysed. The classic, traditional role as an expert deciding the curriculum......, providing lectures and seminars, giving assignments, and marking papers and essays is complemented and in some ways overruled by a new role as supervisor and facilitator for the group of students working with a research problem that they have picked themselves. However, different dimensions of this new...
[Psychological problems of thalassemic subjects].
Guasco, G; La Mantia, A; Cuniolo, A
Analysis of psychological problems of the thalassemic subject shown with these following tests: Der Baumtest, drawing of the human figure. Moreover, we made meetings with all boys and their parents during their stay in the day-hospital. These tests have shown subjective conflicts (fear and uncertainty of future due to illness felt as aggression and fault, depressive moods and loneliness, problems of communication, hope in a magic recovery opposite to the constant discomfort of the therapeutic dependence) and relational conflicts (ambivalence towards parents, difficulties in becoming a part of the social and school environment).
Problems in astrophysical radiation hydrodynamics
International Nuclear Information System (INIS)
The basic equations of radiation hydrodynamics are discussed in the regime that the radiation is dynamically as well as thermally important. Particular attention is paid to the question of what constitutes an acceptable approximate non-relativistic system of dynamical equations for matter and radiation in this regime. Further discussion is devoted to two classes of application of these ideas. The first class consists of problems dominated by line radiation, which is sensitive to the velocity field through the Doppler effect. The second class is of problems in which the advection of radiation by moving matter dominates radiation diffusion
Fluid mechanics problems and solutions
Spurk, Joseph H
his collection of over 200 detailed worked exercises adds to and complements the textbook Fluid Mechanics by the same author, and illustrates the teaching material through examples. In the exercises the fundamental concepts of Fluid Mechanics are applied to obtaining the solution of diverse concrete problems, and in doing this the student's skill in the mathematical modeling of practical problems is developed. In addition, 30 challenging questions without detailed solutions have been included, and while lecturers will find these questions suitable for examinations and tests, the student himself can use them to check his understanding of the subject.
Complex analogues of real problems
DEFF Research Database (Denmark)
Esdahl-Schou, Rune
This thesis will be a mix of different problems in number theory. As such it is split into two natural parts. The rst part focuses on normal numbers and construction of numbers that are normal to a given complex base. It is written in the style of a thorough and introductory paper on that subject...... and Velani, and inspired by this An gave a different proof which provides a stronger result. The conjecture is concerned with intersections of certain sets in the plane and are as such a real problem. We will consider a slightly different setup where the real plane is replaced by the complex plane. Using...
Igor Vasileviсh Malimonov; Liudmila Gennad'evna Korol; Irina Georgievna Sinkovskaya; Dmitriy Vladimiroviсh Rakhinskiy
In article problems of preparation of student's youth for creation of a family are consi-dered.Work purpose: studying of features of marriage behavior of student's youth. Interest in a problem is actual and caused by an instability situation in society, lack of uniform system of values that can lead to disintegration of a family as social institute. Bases of fundamental value of a family and marriage for development and maintenance of stability in society and the state are analysed.Method of ...
Beginnings of the Cauchy problem
Choquet-Bruhat, Yvonne
Brief account of results on the Cauchy problem for the Einstein equations starting with early the works of Darmois and Lichnerowicz and going up to the proofs of the existence and uniqueness of solutions global in space and local in time, in Sobolev spaces, for the general equations either in vacuum or with classical sources.
Pizlo, Zygmunt
This paper presents a bibliography of more than 200 references related to human problem solving, arranged by subject matter. The references were taken from PsycInfo database. Journal papers, book chapters, books and dissertations are included. The topics include human development, education, neuroscience, research in applied settings, as well as animal studies.
Pizlo, Zygmunt
This paper presents a bibliography of 100 references related to human problem solving, arranged by subject matter. The references were taken from PsycInfo database. Journal papers, book chapters, and dissertations are included. The topics include human development, education, neuroscience, and research in applied settings, as well as animal studies.
Childhood Obesity: A Heavy Problem
Costley, Kevin C.; Leggett, Timothy
The youth of today are faced with a big problem; they are becoming more obese every day. The time of children playing outside all day and being extremely active has been overtaken by the television and video games. The days of sitting down as a family and eating a good healthy meal has been replaced by the rush to the nearest fast food…
Frames and extension problems I
DEFF Research Database (Denmark)
Christensen, Ole
In this article we present a short survey of frame theory in Hilbert spaces. We discuss Gabor frames and wavelet frames and set the stage for a discussion of various extension principles; this will be presented in the article Frames and extension problems II (joint with H.O. Kim and R.Y. Kim)....
Quantum Solution of Coordination Problems
Huberman, B A; Hogg, Tad; Huberman, Bernardo A.
We present a quantum solution to coordination problems that can be implemented with present technologies. It provides an alternative to existing approaches, which rely on explicit communication, prior commitment or trusted third parties. This quantum mechanism applies to a variety of scenarios for which existing approaches are not feasible.
Clustering problems for geochemical data
International Nuclear Information System (INIS)
The Union Carbide Corporation, Nuclear Division, Uranium Resource Evaluation Project uses a two-stage sampling program to identify potential uranium districts. Cluster analysis techniques are used in locating high density sampling areas as well as in identifying potential uranium districts. Problems are considered involving the analysis of multivariate censored data, laboratory measurement error, and data standardization
Inner shell energies: experimental problems
International Nuclear Information System (INIS)
Progress in theoretical estimates of single vacancy atomic term values has challenged available experimental data. This brief survey of the experimental situation indicates both conceptual and technical problems which are currently faced. Although these interpretational difficulties are formidable, the emergence of systematic trends in the comparison of theory and experiment appears to invite a simple explication
Eldercare at Home: Skin Problems
... can ease the symptoms. Doctors often prescribe an anti-viral drug, such as acyclovir (ZoviraxTM), valacyclovir (ValtrexTM), ... dealing with common caregiving problems. © 2016 Health in Aging. All rights reserved. Feedback • Site Map • Privacy Policy • ...
The Problem of Private Language
Directory of Open Access Journals (Sweden)
M.A Abdollahi
This language is, according to Wittgenstein, impossible because it leads to epistemological and semantic skepticism. The definition of private language contains two elements: the "privacy" and "referring to". Wittgenstein shows how we may be trapped in solipsism and the only way to avoid this problem is to consider language as a social phenomenon.
Indian Academy of Sciences (India)
Ali Akbar Navabi; Nematollah Riazi
The cosmological, astrophysical, and nucleocosmochronological methods for estimating the age of the universe and the corresponding uncertainties are comparatively studied in the present paper.We are led to the conclusion that the newmeasurements of cosmological parameters, and the recent estimates of the age of globular clusters have led to the gradual disappearance of the age problem from the arena of modern cosmology.
The Vessel Schedule Recovery Problem
DEFF Research Database (Denmark)
Brouer, Berit Dangaard; Plum, Christian Edinger Munk; Vaaben, Bo;
Maritime transportation is the backbone of world trade and is accountable for around 3% of the worlds CO2 emissions. We present the Vessel Schedule Recovery Problem (VSRP) to evaluate a given disruption scenario and to select a recovery action balancing the trade off between increased bunker...
The bicriterion stochastic knapsack problem
DEFF Research Database (Denmark)
Andersen, Kim Allan
We discuss the bicriterion stochastic knapsack problem. It is described as follows. We have a known capacity of some resource, and a finite set of projects. Each project requires some units of the resource which is not known in advance, but given by a discrete probability distribution with a finite...
DEFF Research Database (Denmark)
Vidal, Rene Victor Valqui
The paper studies the problem of determining the number and dimensions of sizes of apparel so as to maximize profits. It develops a simple one-variable bisection search algorithm that gives the optimal solution. An example is solved interactively using a Macintosh LC and Math CAD, a mathematical...
DEFF Research Database (Denmark)
Rosendal, Marianne; Carlsen, Anders Helles; Rask, Mette Troellund
Dette studie undersøger tilfredsheden hos patienter, der blev afsluttet i almen praksis uden specifik diagnose, dvs. hvor lægen efter afsluttet konsultation kun kunne anføre "symptom" eller "problem" som slutdiagnose. Det drejer sig om ca. 1/3 af alle helbredsrelaterede konsultationer i almen...
Quantum Annealing of Hard Problems
Jorg, Thomas; Krzakala, Florent; Kurchan, Jorge; Maggs, A C
Quantum annealing is analogous to simulated annealing with a tunneling mechanism substituting for thermal activation. Its performance has been tested in numerical simulation with mixed conclusions. There is a class of optimization problems for which the efficiency can be studied analytically using techniques based on the statistical mechanics of spin glasses.
Coping with School Adaptation Problems
Cowen, Emory L.
Strategems to cope with maladaptation have been limited in effectiveness. Presented are some key problems they present as well as guidelines for a conceptually preferable set of strategems emphasizing principles which should serve to cut down materially on school maladjustment and restore children to effective school function. (Author/BY)
Quantum Statistics and Entanglement Problems
Trainor, L. E. H.; Lumsden, Charles J.
Interpretations of quantum measurement theory have been plagued by two questions, one concerning the role of observer consciousness and the other the entanglement phenomenon arising from the superposition of quantum states. We emphasize here the remarkable role of quantum statistics in describing the entanglement problem correctly and discuss the relationship to issues arising from current discussions of intelligent observers in entangled, decohering quantum worlds.
Problem Gambling on College Campuses
McComb, Jennifer L.; Hanson, William E.
The vast majority of college students gamble, with some doing so problematically. This article discusses gambling and problem gambling among college students, framing it as an emerging health issue on college campuses nationwide. Given that 4 out of 5 college students admit to gambling, and that approximately 8% gamble problematically, it is…
Institute of Scientific and Technical Information of China (English)
陈树中; 曹立
A new list of regular feedback invariant integers called right independent orders is introduced.That the restricted Morgan's problem is equivalent to a kind of nonlinear algebraic equations is proved and the condition that the nonlinear algebraic equations degenerate into linear algebraic equations is given.
The distributed wireless gathering problem
Bonifaci, V.; Korteweg, P.; Spaccamela, A. Marchetti; Stougie, L.
We address the problem of data gathering in a wireless network using multi-hop communication; our main goal is the analysis of simple algorithms suitable for implementation in realistic scenarios. We study the performance of distributed algorithms, which do not use any form of local coordination, an
Inconsistent Investment and Consumption Problems
DEFF Research Database (Denmark)
Kronborg, Morten Tolver; Steffensen, Mogens
In a traditional Black–Scholes market we develop a verification theorem for a general class of investment and consumption problems where the standard dynamic programming principle does not hold. The theorem is an extension of the standard Hamilton–Jacobi–Bellman equation in the form of a system...
Musculoskeletal problems in stroke survivors.
Kendall, Richard
Musculoskeletal problems in stoke survivors are common reasons for disability and pain. Shoulder pain is present in 24% of stroke survivors among all complications, second only to depression in 26%. Diagnosis and treatment of the various shoulder pain etiologies can significantly improve quality of life in these patients. This article reviews the common etiologies and treatments of shoulder and hip pain in stroke survivors.
On Labeled Traveling Salesman Problems
DEFF Research Database (Denmark)
Couetoux, Basile; Gourves, Laurent; Monnot, Jerome;
We consider labeled Traveling Salesman Problems, defined upon a complete graph of n vertices with colored edges. The objective is to find a tour of maximum (or minimum) number of colors. We derive results regarding hardness of approximation, and analyze approximation algorithms for both versions...
Problem-Oriented Project Studies
DEFF Research Database (Denmark)
Nielsen, Jørgen Lerche; Danielsen, Oluf
Focus is on problem-based learning in a networked learning context with focus on the use of technologies in the communicative processes among the participants. Especially, the role of the teacher in such a context is analysed. The classic, traditional role as an expert deciding the curriculum, pr...
Polyomino Problems to Confuse Computers
Coffin, Stewart
Computers are very good at solving certain types combinatorial problems, such as fitting sets of polyomino pieces into square or rectangular trays of a given size. However, most puzzle-solving programs now in use assume orthogonal arrangements. When one departs from the usual square grid layout, complications arise. The author--using a computer,…
Dube, Rakesh
Removed by arXiv administration. This article was plagiarized directly from Stephen Cook's description of the problem for the Clay Mathematics Institute. See http://gauss.claymath.org:8888/millennium/P_vs_NP/pvsnp.pdf for the original text.
Bankernes problemer er ikke forbi
DEFF Research Database (Denmark)
Bechmann, Ken L.; Grosen, Anders; Hansen, Jørn Astrup
Vi har alle tydeligt kunnet se, at bankerne havde store problemer henover finanskrisen. Men mange er efterhånden kommet til den opfattelse, at det nu går mod lysere tider, og at situationen for bankerne langsomt er ved at normalisere sig. Men en velunderbygget artikel i dette nummer af Finans/Invest...
Allocation Problems and Market Design
DEFF Research Database (Denmark)
Smilgins, Aleksandrs
with fractional players to allocate the common cost in an entity to the finite number of outputs. The paper is concerned with the computation of Aumann-Shapley prices when the cost function is estimated as a convex hull of a set of observed data points. It is discussed how to overcome certain problems related...
Famous Problems and Their Mathematicians.
Johnson, Art
Beginning with more than 60 mathematics problems commonly taught in middle and high school, this book shares the excitement and mystery of mathematics, shows students how 60 mathematicians discovered mathematical solutions, and demonstrates how these discoveries can be applied to everyday situations. Each chapter presents the historical background…
Problems, Perseverance, and Mathematical Residue.
Thom, Jennifer S.; Pirie, Susan E. B.
Reports on a study in which three 3rd grade students were presented with the volume of cuboids. Examines the problem solving actions students demonstrate and analyzes students' strategies and solutions. Explores the connection between spatial structuring and the use of numerical operation. Considers perseverance and control emerging when solving…
Introduction: Unsolved Problems on Noise
Oriols, X.; Ciliberto, S.
This paper is an introduction to the special issue of the 7th Int. Conf. on Unsolved Problems on Noise (UPoN) that took place at Casa Convalescència in Barcelona (Spain) in July 2015. The aim of the UPoN conferences is to provide a forum for researchers working on different fields of noise, fluctuations and variability, where they present their scientific problems which resist solutions. The papers of this Special Issue reflect the interdisciplinary topics (physics, biology, circuits, financial markets, psychology, technology, etc) presented at the UPoN conference. Noise is not only a hindrance to signal detection, but it is indeed a valuable source of information (not present in the signal) that help us to get a deeper understanding on how Nature works. This special issue of the 7th International Conference on Unsolved Problems on Noise (UPoN) is dedicated to Laszlo Kish in the occasion of his 60th birthday. He organized the first edition of these UPoN conferences in Szeged (Hungary) in 1996. Many of us have greatly benefited from his 'volcanic imagination in tackling new problems from unconventional points of views'.
Kryachko, O.
This article deals with the problems of intercultural communication as a developing science, analyses its formation, stages and main approaches. It also presents the possible vectors of its development. World's evolution demands healthy coexistence not only between different countries, but within one country, one ethnic, one group of people. It discusses both social and individual factors which influence the act of communication.
On transfer during problem solving
R. Hamel; E. Jakab
A puzzle is equally new for everyone who is presented with it for the first time. However, it is not if we take one's previous knowledge into account. Some knowledge may be utilised while working on the puzzle. If this is the case, problem solving as well as the development of knowledge about the pu
Management problems of staff motivation
Staff motivation is a major link in improving the competitiveness of any organization. One of the main problems of management of motivation of staff is the individuality of each employee, so the knowledge of psychology and individual needs will help organizations effectively manage staff.
Investigating the Antibiotic Resistance Problem.
Lawson, Michael; Lawson, Amy L.
Seeks to give teachers useful information on the extent of the problem of antibiotic-resistant bacteria, mechanisms bacteria use to resist antibiotics, the causes of the emergence of antibiotic-resistant organisms, and practices that can prevent or reverse this trend. Contains 19 references. (DDR)
Problems in unification and supergravity
International Nuclear Information System (INIS)
Problems in unification of the various gauge groups, quantum gravity, supersymmetry and supergravity, compact dimensions of space-time, and conditions at the beginning of the universe are discussed. Separate entries were prepared for the data base for the 15 papers presented
Isac Florin Lucian; Rusu Sergiu; Cureteanu Radu Silviu
Companies that embrace client orientation are preoccupied by measuring the level of satisfaction of those who consume their products or utilizes their products. That is why, customer satisfaction has to be transposed in measurable parameters that can be understood and influenced. Nevertheless, measuring customer satisfaction involves a lot of problems.
Directory of Open Access Journals (Sweden)
Isac Florin Lucian
Full Text Available Companies that embrace client orientation are preoccupied by measuring the level of satisfaction of those who consume their products or utilizes their products. That is why, customer satisfaction has to be transposed in measurable parameters that can be understood and influenced. Nevertheless, measuring customer satisfaction involves a lot of problems.
Solving the wrong hierarchy problem
Blinov, Nikita; Hook, Anson
Many theories require augmenting the Standard Model with additional scalar fields with large order one couplings. We present a new solution to the hierarchy problem for these scalar fields. We explore parity- and Z_2 -symmetric theories where the Standard Model Higgs potential has two vacua. The parity or Z_2 copy of the Higgs lives in the minimum far from the origin while our Higgs occupies the minimum near the origin of the potential. This approach results in a theory with multiple light scalar fields but with only a single hierarchy problem, since the bare mass is tied to the Higgs mass by a discrete symmetry. The new scalar does not have a new hierarchy problem associated with it because its expectation value and mass are generated by dimensional transmutation of the scalar quartic coupling. The location of the second Higgs minimum is not a free parameter, but is rather a function of the matter content of the theory. As a result, these theories are extremely predictive. We develop this idea in the context of a solution to the strong CP problem. We show this mechanism postdicts the top Yukawa to be within 1 σ of the currently measured value and predicts scalar color octets with masses in the range 9-200 TeV.
Eberstadt, Mary
Experts believe that child obesity is a serious medical problem that affects people in all socioeconomic groups. Suggests that there is a relationship between absentee parents, particularly mothers, and obese children, focusing on working/absentee mothers, television watching habits, the prophylactic effect of breastfeeding, and poor exercise…
"Top School Problems" Are Myths.
Males, Mike
A well-known "study" comparing the top school problems of 1940 (talking and gum chewing) with those of 1987 (drug abuse, pregnancy, and violence) is nonexistent. In 1940, 49 percent of all youth did not finish high school, 37,000 teenagers died from violence or disease, and 335,000 teens gave birth. Educators should discount pastoral memories and…
International Nuclear Information System (INIS)
The problems of the production and consumption of the native uranium in the nuclear fuel cycle are discussed. The ways of the investigations into the reserves of the starting materials and reprocessing of the products on the basis of zirconium, rare earth concentrates, fluorite (for fluoride production), lithium, niobium and tantalum ore are noted
Pizlo, Zygmunt
This paper presents a bibliography of a little more than 100 references related to human problem solving, arranged by subject matter. The references were taken from PsycInfo and Compendex databases. Only journal papers, books and dissertations are included. The topics include human development, education, neuroscience, research in applied…
Problems with German Science Education.
Riess, Falk
The main problems of science teaching in Germany are students' lack of interest and motivation and their poor understanding of scientific concepts, ideas, methods, and results. Lists examples from science curricula and textbooks and describes some reform projects in Germany. Proposes a compensatory program in order to create prerequisites for…
Personal Law and Consumer Problems
Graf, David
There is little doubt at Minnetonka High School that the integrated personal law and consumer problems course is effective. The areas studied promote variety, concentration on vital matters, and student interest in the business department as a source of general education. (Author)
Cavitation problems in sodium valves
International Nuclear Information System (INIS)
Cavitation poses few problems for sodium valves, in spite of the fact that the loops are not pressurized. This is no doubt due to the low flow velocities in the pipes. For auxiliary loop valves we are attempting to standardize performances with respect to cavitation. For economic reasons cavitation thresholds are approached with large diameter valves. (author)
Tube problems: worldwide statistics reviewed
International Nuclear Information System (INIS)
EPRI's Steam Generator Strategic Management Project issues an annual report on the progress being made in tackling steam generator problems worldwide, containing a wealth of detailed statistics on the status of operating units and degradation mechanisms encountered. A few highlights are presented from the latest report, issued in October 1993, which covers the period to 31 December 1992. (Author)
Modified Block Iterative Method for Solving Convex Feasibility Problem, Equilibrium Problems and Variational Inequality Problems
Institute of Scientific and Technical Information of China (English)
Shi Sheng ZHANG; Chi Kin CHAN; H.W. JOSEPH LEE
The purpose of this paper is by using the modified block iterative method to propose an algorithm for finding a common element in the intersection of the set of common fixed points of an infinite family of quasi-φ-asymptotically nonexpansive and the set of solutions to an equilibrium problem and the set of solutions to a variational inequality.Under suitable conditions some strong convergence theorems are established in 2-uniformly convex and uniformly smooth Banach spaces.As applications we utilize the results presented in the paper to solving the convex feasibility problem (CFP) and zero point problem of maximal monotone mappings in Banach spaces.The results presented in the paper improve and extend the corresponding results announced by many authors.
A Formal Description of Problem Frames
Directory of Open Access Journals (Sweden)
Souleymane KOUSSOUBE
Full Text Available Michael Jackson defines a Problem Frame as a mean to describe and classify software development problems. The initial description of problem Frames is essentially graphical. A weakness of this proposal is the lack of formal specification allowing efficient reasoning tools. This paper deals with Problem Frames' formal specification with Description Logics. We first propose a formal terminology of Problem Frames leading to the specification of a Problem Frames' TBOX and a specific problem's ABOX. The Description Logics inference tools can then be used to decompose multi frame problems or to fix a particular problem into a Problem Frame.
Formal language constrained path problems
Energy Technology Data Exchange (ETDEWEB)
Barrett, C.; Jacob, R.; Marathe, M.
In many path finding problems arising in practice, certain patterns of edge/vertex labels in the labeled graph being traversed are allowed/preferred, while others are disallowed. Motivated by such applications as intermodal transportation planning, the authors investigate the complexity of finding feasible paths in a labeled network, where the mode choice for each traveler is specified by a formal language. The main contributions of this paper include the following: (1) the authors show that the problem of finding a shortest path between a source and destination for a traveler whose mode choice is specified as a context free language is solvable efficiently in polynomial time, when the mode choice is specified as a regular language they provide algorithms with improved space and time bounds; (2) in contrast, they show that the problem of finding simple paths between a source and a given destination is NP-hard, even when restricted to very simple regular expressions and/or very simple graphs; (3) for the class of treewidth bounded graphs, they show that (i) the problem of finding a regular language constrained simple path between source and a destination is solvable in polynomial time and (ii) the extension to finding context free language constrained simple paths is NP-complete. Several extensions of these results are presented in the context of finding shortest paths with additional constraints. These results significantly extend the results in [MW95]. As a corollary of the results, they obtain a polynomial time algorithm for the BEST k-SIMILAR PATH problem studied in [SJB97]. The previous best algorithm was given by [SJB97] and takes exponential time in the worst case.
This article observes problem-based learning where students engage complex, challenging problems and collaboratively work toward their resolution. Problem-based learning is about students connecting disciplinary knowledge to real-world problems - the motivation to solve a problem becomes the motivation to learn.
Genetic Algorithm for Chinese Postman Problems
Institute of Scientific and Technical Information of China (English)
Jiang Hua; Kang Li-shan
Chinese Postman Problem is an unsettled graphic problem. It was approached seldom by evolutionary computation. Now we use genetic algorithm to solve Chinese Postman Problem in undirected graph and get good results. It could be extended to solve Chinese postman problem in directed graph. We make these efforts for exploring in optimizing the mixed Chinese postman problem.
Anticipating Student Responses to Improve Problem Solving
Wallace, Ann H.
This article illustrates how problem solving can be enhanced through careful planning and problem presentation. Often, students shut down or are turned off when presented with a problem to solve. The author describes how to motivate students to embrace a problem to be solved and provides helpful prompts to further the problem-solving process.…
Governance of wicked climate adaptation problems
Termeer, C.J.A.M.; Dewulf, A.; Breeman, G.E.
Climate change adaptation has been called a "wicked problem par excellence." Wicked problems are hard to define because 'the formulation of the problem is the problem; they are considered a symptom of another problem; they are highly resistant to solutions and extremely interconnected with other pro
Community Providers' Views of Alcohol Problems and Drug Problems
Gassman, Ruth A.; Weisner, Constance
This study contrasts community health and social service providers' views on alcohol vs. other drug abuse. A probability sample of 457 social work and other providers from a county's public and private medical and mental health clinics, welfare and criminal justice systems, and substance abuse programs, as well as clergy, private therapists, and physicians were interviewed. For both alcohol and drug problems, providers thought only of severe dysfunctions, which suggest that less severe forms ...
Children's Health Problems and Maternal Work Status.
Salkever, David S.
This paper estimates the influence on working mothers' employment status of children's health problems. Effects are estimated for several different types of families, various groups of health problems, and differing degrees of problem severity. (CT)
Non-normal Hasemann Boundary Value Problem
Institute of Scientific and Technical Information of China (English)
We will discuss the non-normal Hasemann boundary value problem:we may find these results are coincided with those of normal Hasemann boundary value problem and non normal Riemann boundary value problem.
[Several problems concerning population investment].
Liu, Z
Population investment is a major topic in the studies of population and economic relations. In this particular area, numerous theoretical and practical problems are still in need of solution. Concerning the problem of population concept, there are three different approaches: (1) to determine the definition of population investment from the relationship between the population growth and the capital from national income used for investment, including investment in the newly increased population and investment in the entire population; (2) to explain population investment from the economic viewpoint that people are producers; and (3) to explain population investment from the expense needed to change a simple labor force to a skillful labor force. The expenses include educational costs, maintanance spending, wages needed to compensate workers in labor, costs for workers to master and learn modern scientific techniques to be used for production, and the costs of keeping a young labor force in the next generation.
Stochastic problems in population genetics
Maruyama, Takeo
These are" notes based on courses in Theoretical Population Genetics given at the University of Texas at Houston during the winter quarter, 1974, and at the University of Wisconsin during the fall semester, 1976. These notes explore problems of population genetics and evolution involving stochastic processes. Biological models and various mathematical techniques are discussed. Special emphasis is given to the diffusion method and an attempt is made to emphasize the underlying unity of various problems based on the Kolmogorov backward equation. A particular effort was made to make the subject accessible to biology students who are not familiar with stochastic processes. The references are not exhaustive but were chosen to provide a starting point for the reader interested in pursuing the subject further. Acknowledgement I would like to use this opportunity to express my thanks to Drs. J. F. Crow, M. Nei and W. J. Schull for their hospitality during my stays at their universities. I am indebted to Dr. M. Kimura...
Modern problems in insurance mathematics
Martin-Löf, Anders
This book is a compilation of 21 papers presented at the International Cramér Symposium on Insurance Mathematics (ICSIM) held at Stockholm University in June, 2013. The book comprises selected contributions from several large research communities in modern insurance mathematics and its applications. The main topics represented in the book are modern risk theory and its applications, stochastic modelling of insurance business, new mathematical problems in life and non-life insurance, and related topics in applied and financial mathematics. The book is an original and useful source of inspiration and essential reference for a broad spectrum of theoretical and applied researchers, research students and experts from the insurance business. In this way, Modern Problems in Insurance Mathematics will contribute to the development of research and academy–industry co-operation in the area of insurance mathematics and its applications.
Numerical models for differential problems
Quarteroni, Alfio
In this text, we introduce the basic concepts for the numerical modelling of partial differential equations. We consider the classical elliptic, parabolic and hyperbolic linear equations, but also the diffusion, transport, and Navier-Stokes equations, as well as equations representing conservation laws, saddle-point problems and optimal control problems. Furthermore, we provide numerous physical examples which underline such equations. We then analyze numerical solution methods based on finite elements, finite differences, finite volumes, spectral methods and domain decomposition methods, and reduced basis methods. In particular, we discuss the algorithmic and computer implementation aspects and provide a number of easy-to-use programs. The text does not require any previous advanced mathematical knowledge of partial differential equations: the absolutely essential concepts are reported in a preliminary chapter. It is therefore suitable for students of bachelor and master courses in scientific disciplines, an...
The environmental problems in Estonia
Energy Technology Data Exchange (ETDEWEB)
Kallaste, T. (Institute of Economics, Estonian Academy of Scinece, Tallinn, Estonia (SU))
This chapter gives a brief overview of Estonia's environmental pollution situation and some problems connected with it. Intensive use of local natural resources, especially oil shale, have deteriorated natural environment in the North-East Estonia. All the components of environment have been seriously damaged by industrial pollution. This has also had an effect on human health. The need for effective pollution monitoring and control system is being suggested for the purposes of management of the quality of environment in the national economic system and to stop further decrease of the quality of environment. The main attention is devoted to air pollution. Integrated indicators, air pollution indices for comprehensive assessment of the level of air pollution have been used. To overcome the pollution problems, some possibilities of economic control are described. Actually the payments for the use of natural resources and taxes for pollution, which will be started in Estonia in 1991, are introduced. (author).
Directory of Open Access Journals (Sweden)
Khanna Surabhi
Full Text Available The pharmaceutical industry is under extraordinary strain. Facing the wrath of consumers because of the cost of products, constantly answering the questions of state and federal legislators looking to control health care costs, and losing value in the marketplace, the industry's hands are more than full. A less discussed but substantial problem impacts all of pharmaceutical industry's other problems, counterfeiting. The World Health Organization estimates that counterfeit drugs make up about 10 percent of the global medicine market, and more than 25 percent in developing countries. With counterfeit drugs increasingly finding their way into global distribution chains and ultimately into patients' mouths, it is essential that pharmaceutical companies have effective enforcement strategies to combat the manufacture and distribution of counterfeit drugs.
Retrofitting and the mu Problem
Energy Technology Data Exchange (ETDEWEB)
Green, Daniel; Weigand, Timo; /SLAC /Stanford U., Phys. Dept.
One of the challenges of supersymmetry (SUSY) breaking and mediation is generating a {mu} term consistent with the requirements of electro-weak symmetry breaking. The most common approach to the problem is to generate the {mu} term through a SUSY breaking F-term. Often these models produce unacceptably large B{mu} terms as a result. We will present an alternate approach, where the {mu} term is generated directly by non-perturtative effects. The same non-perturbative effect will also retrofit the model of SUSY breaking in such a way that {mu} is at the same scale as masses of the Standard Model superpartners. Because the {mu} term is not directly generated by SUSY breaking effects, there is no associated B{mu} problem. These results are demonstrated in a toy model where a stringy instanton generates {mu}.
Tsirelson's problem and Kirchberg's conjecture
Fritz, Tobias
Tsirelson's problem asks whether the set of nonlocal quantum correlations with a tensor product structure for the Hilbert space of states coincides with the one where only commutativity between observables located at different sites is assumed. Here it is shown that Kirchberg's QWEP conjecture on C*-algebras implies a positive answer to this question for all bipartite scenarios. The main idea is very simple and consists of relabelling measurement outcomes by complex roots of unity, so that a k-ary observable becomes a unitary of order k. This relates Tsirelson's problem to tensor products of certain group C^*-algebras to which Kirchberg's conjecture applies. For related work, see the simultaneously appearing preprint by Junge et al.
An archetype hydrogen atmosphere problem
Athay, R. G.; Mihalas, D.; Shine, R. A.
Populations for the first three bound states and the continuum of hydrogen are determined for an isothermal hydrostatic atmosphere at 20,000 K. The atmosphere is treated as optically thin in the Balmer and Paschen continua and illuminated by continuum radiation at these wavelengths with prescribed radiation temperatures. The atmosphere is optically thick in the 2-1, 3-1, 3-2 and c-1 transitions. Three stages of approximation are treated: (1) radiative detailed balance in the 2-1, 3-1 and 3-2 transitions, (2) radiative detailed balance in the 3-1 and 3-2 transitions, and (3) all transitions out of detailed balance. The solution of this problem is nontrivial and presents sufficient difficulty to have caused the failure of at least one rather standard technique. The problem is thus a good archetype against which new methods or new implementations of old methods may be tested.
Topology optimization of flow problems
DEFF Research Database (Denmark)
Gersborg, Allan Roulund
of the computed topology design using standard, credible analysis tools with a body-fitted mesh. Also, the thesis encompasses work on how to utilize the finite volume method (FVM) in the topology optimization context. This is motivated by the momentous position the FVM has in the fluid dynamics community......This thesis investigates how to apply topology optimization using the material distribution technique to steady-state viscous incompressible flow problems. The target design applications are fluid devices that are optimized with respect to minimizing the energy loss, characteristic properties...... of the velocity field or mixing properties. To reduce the computational complexity of the topology optimization problems the primary focus is put on the Stokes equation in 2D and in 3D. However, the thesis also contains examples with the 2D Navier-Stokes equation as well as an example with convection dominated...
Networks in social policy problems
Scotti, marco
Network science is the key to managing social communities, designing the structure of efficient organizations and planning for sustainable development. This book applies network science to contemporary social policy problems. In the first part, tools of diffusion and team design are deployed to challenges in adoption of ideas and the management of creativity. Ideas, unlike information, are generated and adopted in networks of personal ties. Chapters in the second part tackle problems of power and malfeasance in political and business organizations, where mechanisms in accessing and controlling informal networks often outweigh formal processes. The third part uses ideas from biology and physics to understand global economic and financial crises, ecological depletion and challenges to energy security. Ideal for researchers and policy makers involved in social network analysis, business strategy and economic policy, it deals with issues ranging from what makes public advisories effective to how networks influenc...
A bicriterion Steiner tree problem on graph
Directory of Open Access Journals (Sweden)
Vujošević Mirko B.
Full Text Available This paper presents a formulation of bicriterion Steiner tree problem which is stated as a task of finding a Steiner tree with maximal capacity and minimal length. It is considered as a lexicographic multicriteria problem. This means that the bottleneck Steiner tree problem is solved first. After that, the next optimization problem is stated as a classical minimums Steiner tree problem under the constraint on capacity of the tree. The paper also presents some computational experiments with the multicriteria problem.
Health problems of domestic pigeons
Pilėnaitė, Ginvilė
In this scientific work the most important problems and advice under the maintenance of pigeons are described. The chapter 1 – introduction. In it it is described the past and the future pigeon breeding in the world and in Lithuania. In 2 chapter biological features of house pigeons are described. In 3 chapter cultivation and duplication of house pigeons is described. In chapter 4 it is described about care of house pigeons, preparation of their nursery and the technical equipment. There desi...
Pizlo, Zygmunt
This paper presents a bibliography of a little more than 100 references related to human problem solving, arranged by subject matter. The references were taken from PsycInfo and Compendex databases. Only journal papers, books and dissertations are included. The topics include human development, education, neuroscience, research in applied settings, as well as animal studies. A few references from artificial intelligence are also given.
Sleep problems in Rett syndrome
YOUNG, Deidra; Nagarajan, Lakshmi; de Klerk, Nick; Jacoby, Peter; Ellaway, Carolyn; Leonard, Helen
Rett syndrome (RTT) is a severe neurological disorder, affecting mainly females. It is generally caused by mutations in the MECP2 gene. Sleep problems are thought to occur commonly in Rett syndrome, but there has been little research on prevalence or natural history. An Australian population-based registry of cases born since 1976 has been operating since 1993, with current ascertainment at 300. The Australian Rett Syndrome Database (ARSD) consists of information about Rett syndrome cases inc...
Sozashvili, N.
Explanation of mutual relations between separate genres and intragenre versions special interest is got with problems of an epic historicism to which in the newest scientific literature hardly paid the attention. The typology of an epic historicism is simultaneously typology of epic genres, typology of development of epic creativity. The historicism cannot be isolated from art system; it makes one of its organic qualities. The knowledge of topology and the general laws of epic creativity open...
Understanding the grey marketing…….Gray markets occur when a product is designed and destined for a particular market, and an intermediary known as a 'gray marketer' brings that product to a second market to sell it for less than its list price in that second market. (David Soberman, 2012)The grey market has been escalating rapidly, leading to a number of problems including loss of revenue and margin, damage to the carrier affiliation, depreciation of the brand, possible liability and safety ...
Aptamers: Problems, Solutions and Prospects
Lakhin, A.; Tarantul, V.; Gening, L.
Aptamers are short single-stranded oligonucleotides that are capable of binding various molecules with high affinity and specificity. When the technology of aptamer selection was developed almost a quarter of a century ago, a suggestion was immediately put forward that it might be a revolutionary start into solving many problems associated with diagnostics and the therapy of diseases. However, multiple attempts to use aptamers in practice, although sometimes successful, have been generally mu...
Corrosion problems of power engineering
International Nuclear Information System (INIS)
The proceedings contain 26 contributions, out of which 11 have been inputted in INIS. These are concerned with methods for the evaluation of corrosion resistance of materials for the nuclear industry, with examination of the corrosion behavior of composite overlays and of steels after the action of decontamination solutions, and with theoretical models of crack propagation. Corrosion problems of steam turbines, steam generator tubes and thermocouple bushings are discussed. (M.D.). 28 figs., 8 tabs., 63 refs
Editorial: Defining Interesting Research Problems
Steven M. Shugan
We argue that research problems are only interesting relative to some external audience. Interesting academic research should impact, at least, that external audience. Hence, we should target our research toward specific external audiences. Several foreboding trends that exacerbate the urgency of this targeting are discussed. To facilitate the targeting task, a partial list of fifteen possible audiences for academic research in marketing is identified. We discuss some of them, including pract...
Problem of professional personality formation
Directory of Open Access Journals (Sweden)
Pryazhnikova E.Yu.
Full Text Available The article presents the current approaches to the problem of professional personality formation. It ana-lyzes the impact of professional identity of students on the choice of the specialist field they make. The article highlights certain aspects of the educational environment which promote to formation of compe-tences in students, relating to their choice of professional occupations. The article presents the analysis of students' internal and external strivings after graduation from the university and their fulfillment.
Steam generators - problems and prognosis
Energy Technology Data Exchange (ETDEWEB)
Tapping, R.L
Steam-generator problems, largely a consequence of corrosion and fouling, have resulted in increased inspection requirements and more regulatory attention to steam-generator integrity. In addition, utilities have had to develop steam-generator life-management strategies, including cleaning and replacement, to achieve design life. This paper summarizes the pertinent data to 1993/1994, and presents an overview of current steam-generator management practices. (author)
Evolution Strategies in Optimization Problems
Cruz, Pedro A F
Evolution Strategies are inspired in biology and part of a larger research field known as Evolutionary Algorithms. Those strategies perform a random search in the space of admissible functions, aiming to optimize some given objective function. We show that simple evolution strategies are a useful tool in optimal control, permitting to obtain, in an efficient way, good approximations to the solutions of some recent and challenging optimal control problems.
Dynamical problem of micropolar viscoelasticity
Indian Academy of Sciences (India)
Rajneesh Kumar; Suman Choudhary
The dynamic problem in micropolar viscoelastic medium has been investigated by employing eigen value approach after applying Laplace and Fourier transformations. An example of infinite space with concentrated force at the origin has been presented to illustrate the application of the approach. The integral transforms have been inverted by using a numerical technique to obtain the displacement components, force stresses, couple stress and microrotation in the physical domain. The results for these quantities are given and illustrated graphically.
Tackling the European Migration Problems
Zimmermann, Klaus F.
A fortress Europe immigration policy is currently observed throughout the European Union. The European migration problem seems to be that, in the face of high and persistent unemployment rates, additional immigration implies further unemployment. This might not be true if immigration helps to erode institutional constraints and enhances labor market flexibility, a point that is seen of particular virtue in the European setting. The paper also argues that past European migration, although limi...
Problems in Navy reimbursable accounting
Kernen, Bernadette A.
Approved for public release, distribution is unlimited The purpose of this thesis is to identify problems in Navy reimbursable accounting and to develop a comprehensive, entry level financial management guide to assist financial managers at the field level in improving their accountability and control over reimbursable funds. This thesis discusses specific procedures for the effective administration and management of Intra- and Interservice Support Agreements, Economy Act Orders, and Proje...
Ванюшкин, Александр Сергеевич
Notwithstanding the existence of the Standard for portfolio management, published by PMI, publications of gurus of project and portfolio management, there are still remaining the series of serious problems in this sphere. In the purposes of operational projects portfolio management we propose to combine method of calendar – grid planning with method of scenarios analysis. Also it is grounded, that the emphasis in monitoring a portfolio must be shifted towards fixing and interpreting changes i...
Health problems in Turner syndrome
Mehdi Salek; Ahmad Reza Okhovvat; Masoumeh Sadeghi; Hamid Reza Roohafza; Roya Kelishadi; Pooneh Memar Ardestani; Masoumeh Raoufei; Mohammad Hossein Moaddab; Hossein Nejadnik
BACKGROUND: Although cardiovascular malformations are well-recognized congenital anomalies in Turner syndrome (TS), other clinical features and a great variety of dysmorphic signs can also be observed. There are few studies about different medical problems in pre-selected groups of patients with Turner syndrome
BACKGROUND: Although cardiovascular malformations are well-recognized congenital anomalies in Turner syndrome (TS), other clinical features and a great variety of dysmorphic signs can also be observed. There are few studies about different medical problems in pre-selected groups of patients with Turner syndrome
Otologic Problems in Turner Syndrome
Ahmadreza Okhovat; Dr. Mahin Hashemipour; Dr. Alireza Majlesi; Mehdi Salek; Masoumeh Raufi; Dr. Saied Hanif Okhovat
Background and Aim: Turner syndrome is the most common sex chromosome abnormality in females, affecting an estimated 3% of all conceiving females. Otologic disease is a common problem in Turner syndrome patients that is due to a combination of small dysfunction Eustachian tube, palatal dysfunction and cochlear malformation.Methods: This study assessed the otologic and audiologic characteristics of a group of Turner syndrome patients. We studied 40 Turner patients aged 10 to 20 years (mean age...
Quantum gravity: the Inverse problem
Bel, Ll.
Quantizing the gravitational field described by General relativity being a notorious difficult, unsolved and maybe meaningless problem I use in this essay a different strategy: I consider a linear theory in the framework of Special relativity where the potentials are the components of four linear forms. General relativity and other similar covariant non linear theories can be formulated in this way. The theory that I propose is Lorentz invariant, linear, simple, and can be quantized following...
Uranium Critical Point Location Problem
Iosilevskiy, Igor
Significant uncertainty of our present knowledge for uranium critical point parameters is under consideration. Present paper is devoted to comparative analysis of possible resolutions for the problem of uranium critical point location, as well as to discussion of plausible scheme of decisive experiment, which could resolve existing uncertainty. New calculations of gas-liquid coexistence in uranium by modern thermodynamic code are included in the analysis.
Stability problems in hyperinflation models
Zink, Helmut
Traditional monetary models of hyperinflation suffer from severe stability problems: equilibria with realistic comparative-static properties are unstable while those with unrealistic comparative statics are stable. In the present paper I develop a model of hyperinflation which is based on an analysis of firms' payment behavior and which uses a weaker concept of stability. The stability properties of this model are consistent with the empirical evidence.
The fundamental problem of accounting
Robert D. Cairns
The fundamental problem of economic accounting is to determine a forwardlooking schedule of rentals, user costs or quasirents to provide for the recovery of irreversible investments. The method derived herein relaxes some restrictive assumptions that are common in capital theory. There can be multiple forms of comprehensive capital. Accounting for all forms of capital, including tangible and intangible capital, is symmetrical. The analytical focus becomes one of fixities and frictions and not...
Elementary Investigation of Transportation Problems
Directory of Open Access Journals (Sweden)
Edit Schmidt
Full Text Available For students learning the simplex method of linear programming it is a wellbelovedoccasion to solve the so-called transportation problem by the method ofdistribution. This method is simple to calculate and easy to follow. The simple way ofsolution suggests that its correctness may be proven by basic means. This paper has twomain aims. One of them is to present the problem and to solve it by basic means. The otherone is the analysis of the so-called array-bases defined for this reason. In case of atransportation problem m stores and n destinations are given, and the goods have to betaken from the stores to the destinations such that the cost of transporting has to beminimal. The unit costs of the transportation are given by an array. In the solution someroutes (elements of the array are chosen and the number of units to transport there isgiven. It will be proven that the routes for the optimal transportation compose a basis, andthe solution is also achieved by those through the searches. (The basis of an m n × arrayconsists of m+n−1 elements such that they do not span a loop. In the proof somecharacteristics of the bases are needed, for example that the number of them is finite. Toprove this it is enough to give an easily calculated upper bound, the exact value is given inthe appendix. As an extra result of this calculation some interesting formulas ofcombinatorics are also proven.
Directory of Open Access Journals (Sweden)
Оксана Александровна Ахмадеева
Full Text Available In Russian conditions, the use of business valuation is accompanied by a number of problems, not only as an obligatory component a legal transaction, but also for the purpose of making management decisions. Ambiguity of interpretation of some key concepts, such as business and the enterprise, cost and value can lead to problems of methodological and applied character. Definition of the concepts of business and enterprise are important to identify the object of valuation and management. Definitions of cost and value are important for setting management objectives and for development of a methodology for assessing business. The concept business isn't defined in the Russian legal framework, and concept definition the enterprise doesn't open all aspects of this economic system. Value remains to one of the most controversial and contradictory concepts, its nature is explained differently. There are many different definitions of value. The existing methodological base of determination the value of business for management has a number of shortcomings: high labor input, complexity of identification of account and assessment of some value creating factors, the limited use of existing assessment methods for certain types of companies and situations, complexity and high probability of errors of forecasting, a problem of coordination of results. Further development of the adapted methods of an enterprise assessment for value management is required.DOI: http://dx.doi.org/10.12731/2218-7405-2014-2-23
Solving the Wrong Hierarchy Problem
Blinov, Nikita
Many theories require augmenting the Standard Model with additional scalar fields with large order one couplings. We present a new solution to the hierarchy problem for these scalar fields. We explore parity- and $\\mathbb{Z}_2$-symmetric theories where the Standard Model Higgs potential has two vacua. The parity or $\\mathbb{Z}_2$ copy of the Higgs lives in the minimum far from the origin while our Higgs occupies the minimum near the origin of the potential. This approach results in a theory with multiple light scalar fields but with only a single hierarchy problem, since the bare mass is tied to the Higgs mass by a discrete symmetry. The new scalar does not have a new hierarchy problem associated with it because its expectation value and mass are generated by dimensional transmutation of the scalar quartic coupling. The location of the second Higgs minimum is not a free parameter, but is rather a function of the matter content of the theory. As a result, these theories are extremely predictive. We develop thi...
Research mathematicians' practices in selecting mathematical problems
DEFF Research Database (Denmark)
Misfeldt, Morten; Johansen, Mikkel Willum
and suggest that mathematics education research could further investigate how students select and develop problems, work with multiple problems over a longer period of time, and use the solutions to problems to support the development of new problems. Furthermore, the negative emotional aspects of being stuck...... in problem solving and students' conceptions of solvability and relevance of or interest in a mathematical problem are areas of research suggested by our study.......Developing abilities to create, inquire into, qualify, and choose among mathematical problems is an important educational goal. In this paper, we elucidate how mathematicians work with mathematical problems in order to understand this mathematical process. More specifically, we investigate how...
Sociale problemer og sociale afvigelser - sociologisk set
DEFF Research Database (Denmark)
Henriksen, Lars Skov
The arcticle presents central classical sociological theories of social problems and social deviance.......The arcticle presents central classical sociological theories of social problems and social deviance....
Fibonacci's Triangle: A Vehicle for Problem Solving.
Ouellette, Hugh
A method for solving certain types of problems is illustrated by problems related to Fibonacci's triangle. The method involves pattern recognition, generalizing, algebraic manipulation, and mathematical induction. (MP)
Problems with plastered external heat insulation. Probleme mit verputzter Aussenwaermedaemmung
Energy Technology Data Exchange (ETDEWEB)
Epple, H.; Foglia, A.; Preisig, H.; Pfefferkorn, J.
Concerning execution, maintenance and service life, walls with plastered external heat insulation constitute an economic method. Owing to experience gained with plastered external heat insulation, it is possible today to provide reliable information on requirements made on ground material and operational execution. The author intends to contribute to a prevention of defects by giving concise examples. A survey on different types of external heat insulation is followed by a treatment of the problem areas of roof-edge connection, base end under ground, modernization of old buildings and cracks in plaster. Principal statements are made concerning steam diffusion, planning, materials and execution.
Authentication: A Standard Problem or a Problem of Standards?
Directory of Open Access Journals (Sweden)
Amanda Capes-Davis
Full Text Available Reproducibility and transparency in biomedical sciences have been called into question, and scientists have been found wanting as a result. Putting aside deliberate fraud, there is evidence that a major contributor to lack of reproducibility is insufficient quality assurance of reagents used in preclinical research. Cell lines are widely used in biomedical research to understand fundamental biological processes and disease states, yet most researchers do not perform a simple, affordable test to authenticate these key resources. Here, we provide a synopsis of the problems we face and how standards can contribute to an achievable solution.
Authentication: A Standard Problem or a Problem of Standards?
Reproducibility and transparency in biomedical sciences have been called into question, and scientists have been found wanting as a result. Putting aside deliberate fraud, there is evidence that a major contributor to lack of reproducibility is insufficient quality assurance of reagents used in preclinical research. Cell lines are widely used in biomedical research to understand fundamental biological processes and disease states, yet most researchers do not perform a simple, affordable test to authenticate these key resources. Here, we provide a synopsis of the problems we face and how standards can contribute to an achievable solution. PMID:27300550
Hybrid tractability of soft constraint problems
Cooper, Martin C
The constraint satisfaction problem (CSP) is a central generic problem in computer science and artificial intelligence: it provides a common framework for many theoretical problems as well as for many real-life applications. Soft constraint problems are a generalisation of the CSP which allow the user to model optimisation problems. Considerable effort has been made in identifying properties which ensure tractability in such problems. In this work, we initiate the study of hybrid tractability of soft constraint problems; that is, properties which guarantee tractability of the given soft constraint problem, but which do not depend only on the underlying structure of the instance (such as being tree-structured) or only on the types of soft constraints in the instance (such as submodularity). We present several novel hybrid classes of soft constraint problems, which include a machine scheduling problem, constraint problems of arbitrary arities with no overlapping nogoods, and the SoftAllDiff constraint with arbi...
Learning from the problems of problem-based learning
Directory of Open Access Journals (Sweden)
Epstein Richard
Full Text Available Abstract Background The last decade has witnessed a rapid expansion of biomedical knowledge. Despite this, fashions in medical education over the same period have shifted away from factual (didactic teaching and towards contextual, or problem-based, learning (PBL. This paradigm shift has been justified by studies showing that PBL improves reasoning and communication while being associated with few if any detectable knowledge deficits. Discussion Analysis of the literature indicates that the recent rapid rise of PBL has closely paralleled the timing of the information explosion. The growing dominance of PBL could thus worsen the problems of information management in medical education via several mechanisms: first, by creating the impression that a defined spectrum of core factual knowledge suffices for clinical competence despite ongoing knowledge expansion (quality cost; second, by dissuading teachers from refining the educational utility of didactic modalities (improvement cost; and third, by reducing faculty time for developing reusable resources to impart factual knowledge more efficiently (opportunity cost. Summary These costs of PBL imply a need for strengthening the knowledge base of 21st-century medical graduates. New initiatives towards this end could include the development of more integrated cognitive techniques for facilitating the comprehension of complex data; the design of differentiated medical curricula for producing graduates with defined high-priority skill sets; and the encouragement of more cost-effective faculty teaching activities focused on the prototyping and testing of innovative commercializable educational tools.
Effects of problem characteristics, capturing problem structure and using analogies on high school students' success on problem-solving
Pedro GARCÍA GALLEGO; Sanjosé López, Vicente; SOLAZ-PORTOLÉS, Joan Josep
This study analyses the influence of academic level, academic itinerary, word problem's context and structure, capturing problem structure, and using analogies on problem-solving. A factorial design was used with one within-subjects variable and several between-subjects variables, which have been selected depending on the hypothesis in question. Two types of booklets containing two word problems and questions about capturing problem structure and using analogies in problem solving, were admin...
[Addiction therapy. Limits, problems, perspectives].
Kalapos, Miklós Péter
In health care, tending is a process, which offers for the patients a continuous watching on, a control, a treatment, and the prevention of worsening of their medical status as well as the reduction of their complaints. In the article, some fundamental segments of tending in addictology are reviewed, particularly paying attention to whom, how, where and how long to take care. On the basis of literature, the author stresses whatever method is used to treat addict patients it is more beneficial to society than the avoidance of any intervention due to the negligence of the problem. Addictology has lost a lot from its power in Hungary. The author recommends the introduction of the methods of health quality assurance to decrease the effect of negative trends seen in addictology. The paper also deals with special patient groups including homeless clients, adolescents, elderly and pregnant patients as well as health care professionals. The author critically mentions the double communication of society, the dual-face character of politics and has the opinion that competences are not clear making the situation confused. As a mistake of the point of view is it regarded that the addictological problems are classified as to belonging to the authority of psychiatry. It is emphasized that multidisciplinary approach is needed to understand the problem and to treat the client. General screening for addictological diseases does not seem possible in the light of low capacity of the system, but the screening of adolescents and pregnant women is definitely recommended. And finally, a financial support for medicines to prevent craving, a moratorium for the continuous changing of rules and law, the sponsoring of harm reduction programs as well as a better utilization of opportunities offered by local drug coordinating boards are proposed. PMID:25411227
Genetics problem solving and worldview
Dale, Esther
The research goal was to determine whether worldview relates to traditional and real-world genetics problem solving. Traditionally, scientific literacy emphasized content knowledge alone because it was sufficient to solve traditional problems. The contemporary definition of scientific literacy is, "The knowledge and understanding of scientific concepts and processes required for personal decision-making, participation in civic and cultural affairs and economic productivity" (NRC, 1996). An expanded definition of scientific literacy is needed to solve socioscientific issues (SSI), complex social issues with conceptual, procedural, or technological associations with science. Teaching content knowledge alone assumes that students will find the scientific explanation of a phenomenon to be superior to a non-science explanation. Formal science and everyday ways of thinking about science are two different cultures (Palmer, 1999). Students address this rift with cognitive apartheid, the boxing away of science knowledge from other types of knowledge (Jedege & Aikenhead, 1999). By addressing worldview, cognitive apartheid may decrease and scientific literacy may increase. Introductory biology students at the University of Minnesota during fall semester 2005 completed a written questionnaire-including a genetics content-knowledge test, four genetic dilemmas, the Worldview Assessment Instrument (WAI) and some items about demographics and religiosity. Six students responded to the interview protocol. Based on statistical analysis and interview data, this study concluded the following: (1) Worldview, in the form of metaphysics, relates to solving traditional genetic dilemmas. (2) Worldview, in the form of agency, relates to solving traditional genetics problems. (3) Thus, worldview must be addressed in curriculum, instruction, and assessment.
International Nuclear Information System (INIS)
Respiratory disease and mortality due to indoor air pollution are amongst the greatest environmental threats to health in the developing countries of Asia. World-wide, acute respiratory infection is the cause of death of at least 5 million children under the age of 5 every year. The World Bank has claimed that smoke from biomass fuels resulted in an estimated 4 million deaths annually amongst infants and children. Most of these deaths occur in developing countries. Combustion in its various forms must head the list of pollution sources in Asia. Combustion of various fuels for domestic heating, lighting and cooking comprises the major source of internally generated pollutants and combustion in industrial plants, power generation and transportation is the major cause of externally generated pollutants. The products of pyrolysis and combustion include many compounds with well-known adverse health effects. These include gases such as CO, CO2, NOx and SO2, volatile organic compounds such as polynuclear aromatic hydrocarbons and nitroamines as well as respirable particulates of variable composition. The nature and magnitude of the health risks posed by these materials vary with season, climate, location housing, method of ventilation, culture and socio-economic status. The most important cause of lung cancer in non-smokers in Northern Asia is the domestic combustion of smoky coal. Acute carbon monoxide poisoning is common in many Asian countries. Roads traffic exhaust pollution is worse in the major cities of South East Asia than almost anywhere else in the world and this externally generated air pollution forms the indoor air for the urban poor. Despite all these major problems there has been a tendency for international agencies to focus attention and resources on the more trivial problems of indoor air encountered in the affluent countries of the West. Regulatory agencies in Asia have been too frequently persuaded that their problems of indoor air pollution are
Solving complex problems a handbook
Schönwandt, Walter; Grunau, Jens; Utz, Jürgen; Voermanek, Katrin
When you're planning something big, problems appear rather quickly. We hear of them on a daily basis. The bigger or more complex a task, the more we have to deal with complicated, multidisciplinary task formulations. In many cases it is architecture, including urban and spatial planning, but also politics and all types of organizational forms, irrespective of whether they are public authorities or private enterprises, which are expected to deliver functional solutions for such challenges. This is precisely where this book is helpful. It introduces a methodology for developing target-specific,
Directory of Open Access Journals (Sweden)
María del Rosario Ayala-Carrillo
Full Text Available School violence is one type of violence that reflects the breakdown of current society. It is impossible to speak of school violence as an isolated phenomenon without establishing nexuses between public and private life, between collective and individual behaviors, between family and community aspects, without making reference to differences in gender and the life stories of those who are the aggressors or the victims, and without considering the patriarchal culture and interpersonal relationships. When all these factor are interrelated, they make the problem of violence a very complex one that requires us to know the different factors in order to understand it and deal with it.
Famous Problems and Their Mathematicians
Johnson, Art
Why did ordering an omelet cost one mathematician his life? Answers to this and other questions are found in this exciting new resource that shows your students how 60 mathematicians discovered mathematical solutions through everyday situations. These lessons are easily incorporated into the present curriculum as an introduction to a math concept, a homework piece, or an extra challenge. Teacher notes and suggestions for the classroom are followed by extension problems and additional background material. This is a great way to spark student interest in math. Grades 5-12.
Effort problem of chemical pipelines
Energy Technology Data Exchange (ETDEWEB)
Okrajni, J.; Ciesla, M.; Mutwil, K. [Silesian Technical University, Katowice (Poland)
The problem of the technical state assessment of the chemical pipelines working under mechanical and thermal loading has been shown in the paper. The pipelines effort after the long time operating period has been analysed. Material geometrical and loading conditions of the crack initiation and crack growth process in the chosen object has been discussed. Areas of the maximal effort have been determined. The material structure charges after the long time operating period have been described. Mechanisms of the crack initiation and crack growth in the pipeline elements have been analysed and mutual relations between the chemical and mechanical influences have been shown. (orig.) 16 refs.
Communications: Roots of the problem
International Nuclear Information System (INIS)
This paper examines the role of communications in the public and political acceptance of nuclear power programs. The authors demonstrate communication principles that can be useful to any technical sector where there is a need to get facts before the public, the legislators, regulators, and the media. The topics of the paper include an examination of the dimensions of the problem, the nuclear industry's communications shortcomings, a brief chronology of events, communications illustrated, suggestions for a nuclear power public image program, and communication channels
String Theory: Progress and Problems
Schwarz, John H.
String theory builds on the great legacy of Yukawa and Tomonaga: New degrees of freedom and control of the UV are two important themes. This talk will give an overview of some of the progress and some of the unsolved problems that characterize string theory today. It is divided into two parts: (1) Connecting String Theory to the Real World; (2) Gauge Theory/String Theory Duality. Two other major subjects, which I will omit, are Black Holes in String Theory and The Impact of String Theory on M...
The Born transmission eigenvalue problem
Cakoni, Fioralba; Colton, David; Rezac, Jacob D.
In this paper we study the distribution of transmission eigenvalues in the complex plane for obstacles whose contrast is small in magnitude. We use a first order approximation of the refractive index to derive and study an approximate interior transmission problem. In the case of spherically stratified media, we prove existence and discreteness of transmission eigenvalues and derive a condition under which the complex part of transmission eigenvalues cannot lie in a strip parallel to the real axis. For obstacles with general shape, we demonstrate that if transmission eigenvalues exist then they form a discrete set.
Vacuum stability problem in QCD
Kim, Youngman; Pak, D G; Park, Chanyong; Tsukioka, Takuya
The problem of existence of a stable vacuum monopole condensation in a pure quantum chromodynamics (QCD) is revised. Our approach is based on using classical stationary non-linear wave type solutions with intrinsic mass scale parameters. Such solutions can be treated as quantum mechanical wave functions describing massive spinless states in the quantum theory. We verify whether non-linear wave type solutions can form vacuum condensates stable against quantum fluctuations within the effective action formalism. We demonstrate that there is a special class of stationary regular solutions representing a Wu-Yang monopole dressed in gluon field which provides a stable color magnetic condensate in a pure QCD.
Institute of Scientific and Technical Information of China (English)
A scheme for dealing with the quantum three-body problem is presented to separate the rotational degrees of freedom completely from the internal ones. In this method, the three-body Schridinger equation is reduced to a system of coupled partial differential equations, depending only upon three internal variables. For arbitrary total orbital angular momentum l and the parity (-1)l+λ (λ=0 or 1), the number of the equations in this system is l+1-λ. By expanding the wavefunction with respect to a complete set of orthonormal basis functions, the system of equations is further reduced to a system of linear algebraic equations.
Institute of Scientific and Technical Information of China (English)
A scheme for dealing with the quantum three-body problem is presented to separate the rotational degrees of freedom completely from the internal ones. In this method, the three-body Schrodinger equation is reduced to a system of coupled partial differential equations, depending only upon three internal variables. For arbitrary total orbital angular momentum l and the parity ( - 1)1+ λ (λ = 0 or 1), the number of the equations in this system is l + 1 - λ . By expanding the wavef unction with respect to a complete set of orthonormal basis functions, the system of equations is further reduced to a system of linear algebraic equations.
Insomnia: an ignored health problem.
Hamblin, Joan E
Insomnia is common in all age groups and impairs quality of life. Untreated insomnia can lead to, or cause worsening of, other health problems. Effective treatment is available. Behavioral approaches should be tried first with chronic insomnia, because they are effective with few adverse effects. A number of medicines are effective for insomnia, but providers need to be cautious with their use because they are expensive, have a number of adverse side effects, and their long-term use has not been studied. PMID:17868765
Institute of Scientific and Technical Information of China (English)
Liu Min-jia
Several problems about ship waves were discussed in the dissertation:(1) Transient ship waves from calmness to the generation of steady-state ship waves were described. (2) The procedure of the formation of the V-shaped steady-state ship waves were clearly shown, and the difference of ship waves on an inviscid fluid and on a viscous fluid was exmined. (3) With the Lighthill two-stage scheme, the algebraic expression for ship waves on a viscous fluid of finite depth was obtained.(4) Singularity on the two boundaries of the ship waves was treated.
From 'troublemakers' to problem solvers
DEFF Research Database (Denmark)
Frandsen, Martin Severin; Pfeiffer Petersen, Lene
This paper presents the experiences and reflexions of a design practitioner working in the field of community development. The case illustrates how participatory design processes can contribute to social change. The paper tells a story of design process where youths from a local school...... but less tangible result of the design process was the change it produced in the social relations in the neighbourhood. By giving them the opportunity to work as designers, the process contributed to a shift in the image of the youths from one of 'troublemakers' to a positive image of collaborative problem...
Single Electron Transistor: Applications & Problems
Directory of Open Access Journals (Sweden)
Om Kumar
Full Text Available The goal of this paper is to review in brief the basic physics of nanoelectronic device single-electron transistor [SET] as well as prospective applications and problems in their applications. SET functioning based on the controllable transfer of single electrons between small conducting "islands". The device properties dominated by the quantum mechanical properties of matter and provide new characteristics coulomb oscillation, coulomb blockade that is helpful in a number of applications. SET is able to shear domain with silicon transistor in near future and enhance the device density. Recent research in SET gives new ideas which are going to revolutionize the random access memory and digital data storage technologies.
Fast Food Problems and Responsibilities
Institute of Scientific and Technical Information of China (English)
Zhang; Jing
<正>People are living in a world that acquires almost everyone to chase efficiency and speed.The real inner quality of daily life is not approximately taken into people's consideration.Fast food is one of the common model reactions of this rapid developing society.Recently,it's getting popular that people would rather have fast food to save time for other extra work.Problems and public concern are following that kind of life condition and someone or something should be put blame on for this.
Problem-oriented project studies
DEFF Research Database (Denmark)
Nielsen, Jørgen Lerche; Danielsen, Oluf
-oriented focusing on how the final product demonstrates the students' 'correct' way to handle the academic aspects of the subject in mind) to a role more focusing on processes, methodological dimensions and stressing the importance of a reflexive approach. Some teachers may even tend to take on a role...... and marking papers / essays is complemented and in some way overruled by a new role as supervisor and facilitator for the group of students working with a research problem, they themselves have picked. However different dimensions of this new teacher role can be seen – from expert in an academic field (result...
Corrosion problems of power engineering
International Nuclear Information System (INIS)
The proceedings of the conference Corrosion Problems of Power Engineering held from 8 to 10 Dec 1987 in Marianske Lazne (CS) contain the full texts of 26 papers of which 12 fall under the INIS Subject Scope. The papers discuss structural materials for the components of the primary and secondary coolant circuits of nuclear power plants with WWER type reactors. Attention is devoted to various aspects of corrosion behaviour of the materials during normal operation of a nuclear power plant and in deactivation agents. (Z.M.)
Major arcs for Goldbach's problem
Helfgott, H. A.
The ternary Goldbach conjecture states that every odd number $n\\geq 7$ is the sum of three primes. The estimation of the Fourier series $\\sum_{p\\leq x} e(\\alpha p)$ and related sums has been central to the study of the problem since Hardy and Littlewood (1923). Here we show how to estimate such Fourier series for $\\alpha$ in the so-called major arcs, i.e., for $\\alpha$ close to a rational of small denominator. This is part of the author's proof of the ternary Goldbach conjecture. In contrast ...
Problems of Chernobyl exclusion zone
International Nuclear Information System (INIS)
The collection comprises the results of researches and design activity in the ChNPP exclusion zone with the aim to develop technology, equipment and instruments for RAW management and accident clean-up, studying of the composition and structure of the activity solid bearers in the soil of the exclusion zone and transformation of the radionuclides in the nearest zone of ChNPP. Much attention is paid to medical and biological problems of the accident influence on the flora, fauna and people's health labour conditions and incidence of the people involved
Problems of Chornobyl Exclusion Zone
International Nuclear Information System (INIS)
The collection comprises the results of researches and design activity in the ChNPP exclusion zone with the aim to develop technology, equipment and instruments for RAW management and accident clean-up, studying of the composition and structure of the activity solid bearers in the soil of the exclusion zone and transformation of the radionuclides in the nearest zone of ChNPP. Much attention is paid to medical and biological problems of the accident influence on the flora, fauna and people's health, labour conditions and incidence of the people involved.
Directory of Open Access Journals (Sweden)
A. A. Kosolapov
Full Text Available Purpose.Computerization and informatization in recent decades gave the mankind automated electronic document management systems, automated process of production, Internet and network information resources WWW, expanded the communications capabilities and led to the globalization of the information society. At the same time gives rise to a number of processes of informatization philosophical and anthropological problems, that has become an existential character. It is necessary to identify and understanding of these issues on the basis of the gnoseological model of the evolution informatization paradigms and determine their main characteristics. Methodology. The system-activity approach was used; it allowed identifying and analyzing the impact of the main components of information and communication technologies (ICT for educational activities. And further to present them as a unified system of human activity in conditions computerization/informatization. The philosophical principles: a comprehensive review of the subject, the unity of the logical and historical, ascending from the abstract to the concrete was used. The general scientific principles: unity and development of the system, the decomposition hierarchy, individualization and cooperation, diversity and taxonomy were applied. Findings.The three-stage gnoseological model of the paradigms computerization/informatization evolution was proposed by the author. It is based on three information system characteristics: speed, interface and data access. The seven-bar anthrop-centric model, which is called the architecture of information systems (AIS, which describes the changes in their types of procuring, was proposed for each paradigm. The philosophical-anthropological problems that affect negatively its progress were formulated for each stage of modern information society transformation. Originality. The gnoseological model of development processes of informatization in the form of three
Revisiting the medical diagnosis problem
DEFF Research Database (Denmark)
Ejersbo, Lisser Rye; Leron, Uri
of such cognitive challenges? In our view, pointing out the clash is not enough; we'd like to help students build bridges between the intuitive and analytical ways of seeing the problem, thus hopefully creating a peaceful co-existence between these two modes of thought. In this article, we investigate this question...... psychological research as a theoretical base, we design a new "bridging" task, which is on the one hand formally equivalent to the given "difficult" task, but on the other hand is much more accessible to students' intuitions. Furthermore, this new task would serve as "stepping stone", enabling students to solve...
Silverlight 4 Problem - Design - Solution
Lecrenski, Nick
A hands-on guide to Microsoft's latest rich application development technology: Silverlight 4. Silverlight 4 is the newest version of the rich Internet application toolkit that provides support for .NET capabilities over the Internet. With this latest release of Silverlight, Microsoft has revolutionized the way that Web applications can be created. This book uses the popular Problem – Design – Solution strategy to demonstrate how to harness the power and abilities of Silverlight 4 to add value to the overall user experience of a Web site. Using a Web site created by the author as a reference p
The Black Hole Information Problem
Polchinski, Joseph
The black hole information problem has been a challenge since Hawking's original 1975 paper. It led to the discovery of AdS/CFT, which gave a partial resolution of the paradox. However, recent developments, in particular the firewall puzzle, show that there is much that we do not understand. I review the black hole, Hawking radiation, and the Page curve, and the classic form of the paradox. I discuss AdS/CFT as a partial resolution. I then discuss black hole complementarity and its limitations, leading to many proposals for different kinds of `drama.' I conclude with some recent ideas.
Kitaev, S.; Mansour, T.
In this paper we study the number $M_{m,n}$ of ways to place nonattacking pawns on an $m\\times n$ chessboard. We find an upper bound for $M_{m,n}$ and analyse its asymptotic behavior. It turns out that $\\lim_{m,n\\to\\infty}(M_{m,n})^{1/mn}$ exists and is bounded from above by $(1+\\sqrt{5})/2$. Also, we consider a lower bound for $M_{m,n}$ by reducing this problem to that of tiling an $(m+1)\\times (n+1)$ board with square tiles of size $1\\times 1$ and $2\\times 2$. Moreover, we use the transfer-...
Health problems in Turner syndrome
Directory of Open Access Journals (Sweden)
Mehdi Salek
Full Text Available BACKGROUND: Although cardiovascular malformations are well-recognized congenital anomalies in Turner syndrome (TS, other clinical features and a great variety of dysmorphic signs can also be observed. There are few studies about different medical problems in pre-selected groups of patients with Turner syndrome. Therefore, in this study we aimed to assess the prevalence of some medical problems in Turner syndrome. METHODS: This was a case series from April to October 2005. We studied 40 patients with TS who attended the Endocrine and Metabolic Research Center. Audiometry, echocardiography, ultrasonography of kidneys and urinary tracts, thyroid function tests, fasting blood sugar, lipid profile as well as anthropometric and blood pressure measurements were assessed in all patients and collected data were analyzed by SPSS version 10. RESULTS: Of the 40 subjects 62.5% (n = 25 had cardiac anomalies, 20% (n = 8 had high blood pressure, about 60% (n = 24 suffered from hearing loss and 15% (n = 6 suffered from duplication or dilatation of urinary collecting system. The relative frequency of hypothyroidism, hypercholesterolemia and hypertriglyceridemia was 25% (n = 10, 30% (n = 12 and 32.5% (n = 13, respectively. CONCLUSIONS: Medical problems are common in TS patients and the routine screening of their health conditions should be performed at the time of diagnosis and at
BACKGROUND: Although cardiovascular malformations are well-recognized congenital anomalies in Turner syndrome (TS, other clinical features and a great variety of dysmorphic signs can also be observed. There are few studies about different medical problems in pre-selected groups of patients with Turner syndrome. Therefore, in this study we aimed to assess the prevalence of some medical problems in Turner syndrome.
METHODS: This was a case series from April to October 2005. We studied 40 patients with TS who attended the Endocrine and Metabolic Research Center. Audiometry, echocardiography, ultrasonography of kidneys and urinary tracts, thyroid function tests, fasting blood sugar, lipid profile as well as anthropometric and blood pressure measurements were assessed in all patients and collected data were analyzed by SPSS version 10.
RESULTS: Of the 40 subjects 62.5% (n = 25 had cardiac anomalies, 20% (n = 8 had high blood pressure, about 60% (n = 24 suffered from hearing loss and 15% (n = 6 suffered from duplication or dilatation of urinary collecting system. The relative frequency of hypothyroidism, hypercholesterolemia and hypertriglyceridemia was 25% (n = 10, 30% (n = 12 and 32.5% (n = 13, respectively.
CONCLUSIONS: Medical problems are common in TS patients and the routine screening of their health conditions should be performed at the time of diagnosis and at
Allelopathy problems at Nardus stricta
Directory of Open Access Journals (Sweden)
Viorica TARAU
Full Text Available Um einige Fragen des Allelopathie Problemes bei Nardus stricta Grunland zu erklaren, haben die Verfasser der vorliegenden Arbeit die Wirkung einiger Bodenlosungen, die dem Boden unter der gut umgrenzten Vegetation der Maulwurfshugel einer Nardus strictae collinum - Assoziation entnommen wurden, auf die Keimung der Samen von Trifolium pretense, Lotus corniculatus, Lolium perene und Phleum pratense verfolgt. Eine starker hemmende Wirkung auf die Keimung aller untersuchten Arten hatten die Losungen aus dem Boden unter Festuca rubra + Agrostis tenuis, Festuca rubra + Polytrichum juniperinum. Nardus stricta hat die Keimung von Trifolium pretense stark gehemmt, wahrend Holcus lanatus die Keimung samtlicher studierten Arten stimuliert hat.
Mobile authentication problems and solutions
Jakobsson, Markus
Mobile Authentication: Problems and Solutions looks at human-to-machine authentication, with a keen focus on the mobile scenario. Human-to-machine authentication is a startlingly complex issue. In the old days of computer security-before 2000, the human component was all but disregarded. It was either assumed that people should and would be able to follow instructions, or that end users were hopeless and would always make mistakes. The truth, of course, is somewhere in between, which is exactly what makes this topic so enticing. We cannot make progress with human-to-machine authentication with
Neurotechnology premises, potential, and problems
Giordano, James
New technologies that allow us to investigate mechanisms and functions of the brain have shown considerable promise in treating brain disease and injury. These emerging technologies also provide a means to assess and manipulate human consciousness, cognitions, emotions, and behaviors, bringing with them the potential to transform society. Neurotechnology: Premises, Potential, and Problems explores the technical, moral, legal, and sociopolitical issues that arise in and from today,s applications of neuroscience and technology and discusses their implications for the future. Some of the issues r
Potential Theory Surveys and Problems
Lukeš, Jaroslav; Netuka, Ivan; Veselý, Jiří
The volume comprises eleven survey papers based on survey lectures delivered at the Conference in Prague in July 1987, which covered various facets of potential theory, including its applications in other areas. The survey papers deal with both classical and abstract potential theory and its relations to partial differential equations, stochastic processes and other branches such as numerical analysis and topology. A collection of problems from potential theory, compiled on the occasion of the conference, is included, with additional commentaries, in the second part of this volume.
Some boys' problems in education
DEFF Research Database (Denmark)
Jørgensen, Christian Helms
of education policy. The purpose of this article is to examine this 'boy problem' in relation to the dual system of vocational education and training (VET) in Denmark. By considering the gender divisions and the value of the VET programmes on the labour market, it explores what kind of problems boys have...... in VET. Secondly, it explores the role of VET for students at risk of dropping out based on individual qualitative interviews with 106 students, two-thirds male, attending vocational schools in Denmark. The analyses show that most students experience the dual system of VET as a valuable alternative...
International Nuclear Information System (INIS)
The Social Impact of the closure of ChNPP is indeed a significant and complex one. There is no one simple solution to the problem but if the effects of closure are to be mitigated effectively all who are involved, be they part of the local community, donor agencies or project staff need to work together towards the common goal, putting aside personal agendas and ensuring that every resource, financial and human, is used in a productive and constructive way complementing the activities of others and not competing with them
Quantum gravity: the Inverse problem
Bel, Ll
Quantizing the gravitational field described by General relativity being a notorious difficult, unsolved and maybe meaningless problem I use in this essay a different strategy: I consider a linear theory in the framework of Special relativity where the potentials are the components of four linear forms. General relativity and other similar covariant non linear theories can be formulated in this way. The theory that I propose is Lorentz invariant, linear, simple, and can be quantized following similar steps to those that led to quantum electrodynamics.
Fuel cells problems and solutions
Bagotsky, Vladimir S
The comprehensive, accessible introduction to fuel cells, their applications, and the challenges they pose Fuel cells-electrochemical energy devices that produce electricity and heat-present a significant opportunity for cleaner, easier, and more practical energy. However, the excitement over fuel cells within the research community has led to such rapid innovation and development that it can be difficult for those not intimately familiar with the science involved to figure out exactly how this new technology can be used. Fuel Cells: Problems and Solutions, Second Edition addresses this i
The Duality on Vector Optimization Problems
Institute of Scientific and Technical Information of China (English)
HUANG Long-guang
Duality framework on vector optimization problems in a locally convex topological vector space are established by using scalarization with a cone-strongly increasing function.The dualities for the scalar convex composed optimization problems and for general vector optimization problems are studied.A general approach for studying duality in vector optimization problems is presented.
Common ground, complex problems and decision making
Beers, P.J.; Boshuizen, H.P.A.; Kirschner, P.A.; Gijselaers, W.H.
Organisations increasingly have to deal with complex problems. They often use multidisciplinary teams to cope with such problems where different team members have different perspectives on the problem, different individual knowledge and skills, and different approaches on how to solve the problem. I
Solving set partitioning problems using lagrangian relaxation
van Krieken, M.G.C.
This thesis focuses on the set partitioning problem. Given a collection of subsets of a certain root set and costs associated to these subsets, the set partitioning problem is the problem of finding a minimum cost partition of the root set. Many real-life problems, such as vehicle routing and crew s
The governance of problems: puzzling, powering, participation
Hoppe, Robert
Policy analysis usually gives more attention to problem solving than problem finding and there is a real threat of mismatch between problem perceptions by citizens and problem definition by their elected and appointed policy makers. Contemporary democracies need to develop a better governance of pro
Problems without Numbers--At First
Hewitt, Paul G.
Three sample physics problems are presented in this article. The solutions to the three problems addresses a major student difficulty in problem solving--knowing where to begin. The first suggested step is to begin by stating what is asked for. Step 2 is identifying the fundamental physics that underlies the problem situation. Step 3 is isolating…
Toward a Design Theory of Problem Solving.
Jonassen, David H.
Proposes a metatheory of problem solving. Describes differences among problems in terms of their structured ness, domain specificity (abstractness), and complexity; describes individual differences that affect problem solving; and presents a typology of problems, each of which engages different cognitive, affective, and conative process and…
Institute of Scientific and Technical Information of China (English)
We consider a backward parabolic problem arising in the description of the behavior of the toroidal part of the magenetic field in a dynamo problem. In our backward time problem, the media parameters are spatial distributed and the boundary conditions are of the Robin type. For this ill-posed problem, we prove that the solution depends continuously on the initial-time geometry.
Journey toward Teaching Mathematics through Problem Solving
Sakshaug, Lynae E.; Wohlhuter, Kay A.
Teaching mathematics through problem solving is a challenge for teachers who learned mathematics by doing exercises. How do teachers develop their own problem solving abilities as well as their abilities to teach mathematics through problem solving? A group of teachers began the journey of learning to teach through problem solving while taking a…
Enhanced Student Learning with Problem Based Learning
Hollenbeck, James
Science educators define a learning environment in which the problem drives the learning as problem based learning (PBL). Problem based learning can be a learning methodology/process or a curriculum based on its application by the teacher. This paper discusses the basic premise of Problem base learning and successful applications of such learning.…
Astronomical problems an introductory course in astronomy
Vorontsov-Vel'Yaminov, B A
Astronomical Problems: An Introductory Course in Astronomy covers astronomical problems, together with a summary of the theory and the formula to be exercised. The book discusses the types of problems solved with the help of the celestial globe and how to solve astronomical problems. The text tackles problems on interpolation, the celestial sphere, systems of celestial coordinates, and culmination. Problems about the rising and setting of a heavenly body, precession, planetary movement, and parallax and aberration are also considered. The book presents problems about refraction, the apparent m
The Lasso Problem and Uniqueness
Tibshirani, Ryan J
The lasso is a popular tool for sparse linear regression, especially for problems in which the number of variables p exceeds the number of observations n. But when p>n, the lasso criterion is not strictly convex, and hence it may not have a unique minimum. An important question is: when is the lasso solution well-defined (unique)? We review results from the literature, which show that if the predictor variables are drawn from a continuous probability distribution, then there is a unique lasso solution with probability one, regardless of the sizes of n and p. We also show that this result extends easily to $\\ell_1$ penalized minimization problems over a wide range of loss functions. A second important question is: how can we deal with the case of non-uniqueness in lasso solutions? In light of the aforementioned result, this case really only arises when some of the predictor variables are discrete, or when some post-processing has been performed on continuous predictor measurements. Though we certainly cannot c...
[Nutritional problems in palliative medicine].
Ollenschläger, G
Malnutrition is a frequent problem in the palliative care of the seriously ill and dying. Want of appetite and los of weight are direct symptoms of patients with consumptive infectional diseases (AIDS, TBC) as well as cancer or geriatric patients. Severe malnutrition significantly contributes to a loss of quality of life and increases morbidity of palliative patients. The subjective well-being of seriously ill patients is heavily influenced by want of appetite and loss of weight. Patients often find want of appetite and the incapability to eat as pressing as the physical impairment caused by the disease. Therefore the sole aim of palliative dietotherapy has to be to strengthen the general physical and mental condition of the patient. A specific training of home care staff and relatives of seriously ill patients in dealing sensitively with this problem of care is desirable. Above all, in-patient treatment of affected patients for the sole purpose of feeding has to be avoided. Aggressive dietotherapeutic interventions, especially artificial feeding, should be refrained from as far as possible in the terminal phase. Only if the prognosis of a patient in palliative treatment is improving contrary to expectations are strategies of curative dietotherapy valid. PMID:11048342
Institute of Scientific and Technical Information of China (English)
Leo C.VAN RIJN
This keynote lecture addresses engineering sedimentation problems in estuarine and coastal environments and practical solutions of these problems based on the results of field measurements,laboratory scale models and numerical models. The three most basic design rules are: (1) try to understand the physical system based on available field data; perform new field measurements if the existing field data set is not sufficient (do not reduce on the budget for field measurements); (2) try to estimate the morphological effects of engineering works based on simple methods (rules of thumb,simplified models,analogy models,i.e. comparison with similar cases elsewhere); and (3) use detailed models for fine-tuning and determination of uncertainties (sensitivity study trying to find the most influencial parameters). Engineering works should be designed in such a way that side effects (sand trapping,sand starvation,downdrift erosion) are minimum. Furthermore,engineering works should be designed and constructed or built in harmony rather than in conflict with nature. This 'building with nature' approach requires a profound understanding of the sediment transport processes in morphological systems.
Directory of Open Access Journals (Sweden)
Igor Vasileviсh Malimonov
Full Text Available In article problems of preparation of student's youth for creation of a family are consi-dered.Work purpose: studying of features of marriage behavior of student's youth. Interest in a problem is actual and caused by an instability situation in society, lack of uniform system of values that can lead to disintegration of a family as social institute. Bases of fundamental value of a family and marriage for development and maintenance of stability in society and the state are analysed.Method of obtaining information: questioning (N=2260. It is shown that on marriage behavior of young people, first of all, such factors as have impact: the relations in a parental family, welfare features of society and their near environment (classmates, friends, values and which norms, lay the foundation of family and marriage installations. Comprehensively social parameters of city life of youth reveal: anonymity, short duration and superficiality of contacts in interpersonal communication; sharp expansion of degree of freedom of the person at simultaneous weakening of social control; disintegration of traditional ideology and system of values; reduction of the importance of a role of a family, etc.Results of research: priority of studying of marriage behavior of youth is proved; domination of independent strategy of premarital elections of youth is confirmed, various components of readiness for the family and marriage relations and the factors influencing motivation of a marriage choice are defined.
Causality problem in Economic Science
Directory of Open Access Journals (Sweden)
Full Text Available The main point of the paper is the problem of the economy to be consider like a science in the most strict term of the concept. In the first step we are going to tackle a presentation about what we understand by science to subsequently present some of the fallacies which have bring certain scepticism about the scientific character of the investigation in economy, to know: 1 The differences between hard and weak sciences -physics and social; 2 The differences between paradigm, —positivist and phenomenological— 3 The differences between physic causalityand historic causality. In the second step we are going to talk about two fundamental problems which are questioned: 1 the confusion between ontology and gnoseology and, 2 the erroneous concept of causality that commonly is used. In the last step of the paper we are going over the recent models of «causal explanation» and we suggest the probabilistic casualty development next with a more elaborated models of causal explanation, like a way to conjugate the scientific severity with the possibility to tackle complex economic realities.
The problem of risk communication
International Nuclear Information System (INIS)
Communication of risk and risk decisions has always been a matter of great difficulty. A great deal of research has been devoted to improving either the understanding of people's perception of risk or people's understanding of risk itself. These achievements have, however, either failed or the results have not been properly introduced in risk communication. At least this is what can be deduced from recent very heated discussions of risk decisions concerning chemical industry in Denmark. It might thus be that the focus of our interest should be changed from improving already existing methods of risk analysis to improving our understanding of why risk communication very often fails - and fails with very severe consequences. In Denmark a working party set up by the Minister for the Environment has just concluded its work on these matters. This main problem seems to be that the authorities' very one-dimensional perception of risk simply do not reflect the concern of the public and that of many politicians. If this is true the problem is not just a matter of communication but a much more fundamental one which parameters should be introduced in risk evaluation in order to satisfy the need of the public - and how this can be done. (author)
The seismic reflection inverse problem
International Nuclear Information System (INIS)
The seismic reflection method seeks to extract maps of the Earth's sedimentary crust from transient near-surface recording of echoes, stimulated by explosions or other controlled sound sources positioned near the surface. Reasonably accurate models of seismic energy propagation take the form of hyperbolic systems of partial differential equations, in which the coefficients represent the spatial distribution of various mechanical characteristics of rock (density, stiffness, etc). Thus the fundamental problem of reflection seismology is an inverse problem in partial differential equations: to find the coefficients (or at least some of their properties) of a linear hyperbolic system, given the values of a family of solutions in some part of their domains. The exploration geophysics community has developed various methods for estimating the Earth's structure from seismic data and is also well aware of the inverse point of view. This article reviews mathematical developments in this subject over the last 25 years, to show how the mathematics has both illuminated innovations of practitioners and led to new directions in practice. Two themes naturally emerge: the importance of single scattering dominance and compensation for spectral incompleteness by spatial redundancy. (topical review)
One solution for two problems.
This article presents Dr. Nicky Padayachee's resolution concerning AIDS and its effect on the problem of overpopulation. Dr. Nicky Padayachee of Johannesburg City Council's Health Department stated that both of these problems pose a threat to the economic development with solutions depending on the development of the country. The increasing population of South Africa in comparison with its economic decline resulted to unemployment and high fertility. It has been proposed that the local government should double its efforts in the promotion of family planning through the provision of electricity and using television as a mode of disseminating family planning information. Further, a strict implementation of optimal urbanization, education and general economic development opportunity for all individuals was suggested. It was estimated that 2.5-7.5 million people will be HIV-positive by the year 2005, and any long-term planning would need essential re-examination and review as the demographic situation unfolds. AIDS education was insufficient by itself to control AIDS, but the stability in education, family life and empowerment of women were important in the implementation of any AIDS prevention program. Generally, development plays a major role in the decrease of AIDS and fertility by providing individuals with opportunities and jobs. On his last statement, he concluded that the best treatment for AIDS and population growth is a job. PMID:12349359
Institute of Scientific and Technical Information of China (English)
Asmuliardi MULUK; Hasan AKPOLAT; Jichao XU
There seems to be a significant gap between the theoretical and the practical aspects of scheduling problems in the job shop environment. Theoretically, scheduling systems are designed on the basis of an optimum approach to the scheduling model. However in the practice, the optimum that is built into the scheduling applications seems to face some challenges when dealing with the dynamic character of a scheduling system, for instance machine breakdown or change of orders. Scheduling systems have become quite complex in the past few years. Competitive business environments and shorter product life cycles are the imminent challenges being faced by many companies these days.These challenges push companies to anticipate a demand driven supply chain in their business environment. A demand-driven supply chain incorporates the customer view into the supply chain processes. As a consequence of this, scheduling as a core process of the demand-driven supply chain must also reflect the customer view. In addition, other approaches to solving scheduling problems, for instance approaches based on human factors, prefer the scheduling system to be more flexible in both design and implementation. After discussion of these factors, the authors propose the integration of a different set of criteria for the development of scheduling systems which not only appears to have a better flexibility but also increased customer-focus.
Molinaro, Marco
In the query-commit problem we are given a graph where edges have distinct probabilities of existing. It is possible to query the edges of the graph, and if the queried edge exists then its endpoints are irrevocably matched. The goal is to find a querying strategy which maximizes the expected size of the matching obtained. This stochastic matching setup is motivated by applications in kidney exchanges and online dating. In this paper we address the query-commit problem from both theoretical and experimental perspectives. First, we show that a simple class of edges can be queried without compromising the optimality of the strategy. This property is then used to obtain in polynomial time an optimal querying strategy when the input graph is sparse. Next we turn our attentions to the kidney exchange application, focusing on instances modeled over real data from existing exchange programs. We prove that, as the number of nodes grows, almost every instance admits a strategy which matches almost all nodes. This resu...
Directory of Open Access Journals (Sweden)
Reinhard Graf
Full Text Available Developmental dysplasia of the hip (DDH is the most frequent developmental disorder of the locomotor system. It is detected among 0.1–5.2% of newborns (1, 2. This might be the reason, that there is a high interest to detect DDH cases as early as possible. Undetected or late cases lead to catastrophes for the patient and family. Limping, leg length discrepancy, pain, frequent operations and sometimes femoral head necrosis, osteoarthritis, disability and finally total hip replacement even in young ages are results of a dysplastic hip that is not diagnosed on time or left untreated or treated improperly. Independent from individual patient problems the treatment costs for late or neglected cases are enormous. Costs of hospitalization, operations, rehabilitation, and indirect costs because of limited ability to work are incredible high. In countries with poor common health-system these patients have no chance for a normal life because of their disability. How to solve or reduce the problem Clinical examination (Ortolani,Barlow etc. is used very often in different countries routinely, but not generally worldwide. The literature is quite clear; clinical examinations can reduce but not solve the problem. It need "well trained and experienced doctors"! But what is the definition of a "well trained and experienced doctor"? How it can happen, that in spite of clinical examination we see neglected cases? More than 5o% of DDH cases does not have any "typical" risk factor. The clinical examination is very often so subjective, that even fully dislocated joints cannot be detected and may be missed. Critical questions 1- What is the Ortolani and the Barlow sign, the Glissement, the dry click sign, the phenomenon of the loose joint capsule and the "click" according to Tönnis D? 2- What sign in what age is normal? When does one of these signs change to the other one? 3- What is the pathology inside the joints, when you feel one of these
Community-powered problem solving.
Gouillart, Francis; Billings, Douglas
Traditionally, companies have managed their constituencies with specific processes: marketing to customers, procuring from vendors, developing HR policies for employees, and so on. The problem is, such processes focus on repeatability and compliance, so they can lead to stagnation. Inviting your constituencies to collectively help you solve problems and exploit opportunities--"co-creation"--is a better approach. It allows you to continually tap the skills and insights of huge numbers of stakeholders and develop new ways to produce value for all. The idea is to provide stakeholders with platforms (physical and digital forums) on which they can interact, get them to start exploring new experiences and connections, and let the system grow organically. A co-creation initiative by a unit of Becton, Dickinson and Company demonstrates how this works. A global leader in syringes, BD set out to deepen its ties with hospital customers and help them reduce the incidence of infections from unsafe injection and syringe disposal practices. The effort began with a cross-functional internal team, brought in the hospital procurement and supply managers BD had relationships with, and then reached out to hospitals' infection-prevention and occupational health leaders. Eventually product designers, nurses, sustainability staffers, and even hospital CFOs were using the platform, contributing data that generated new best practices and reduced infections. PMID:23593769
Solving the factorization problem with P systems
Institute of Scientific and Technical Information of China (English)
Alberto Leporati; Claudio Zandron; Giancarlo Mauri
P systems have been used many times to face with computationally difficult problems, such as NP-complete decision problems and NP-hard optimization problems. In this paper we focus our attention on another computationally intractable problem: factorization. In particular, we first propose a simple method to encode binary numbers using multisets. Then, we describe three families of P systems: the first two allow to add and to multiply two binary encoded numbers, respectively, and the third solves the factorization problem.
Sequential sharing rules for river sharing problems
Ansink, Erik; Weikard, Hans-Peter
We analyse the redistribution of a resource amongst agents who have claims to the resource and who are ordered linearly. A well known example of this particular situation is the river sharing problem. We exploit the linear order of agents to transform the river sharing problem to a sequence of two-agent river sharing problems. These reduced problems are mathematically equivalent to bankruptcy problems and can therefore be solved using any bankruptcy rule. Our proposed class of solutions, that...
The inverse maximum dynamic flow problem
Institute of Scientific and Technical Information of China (English)
BAGHERIAN; Mehri
We consider the inverse maximum dynamic flow (IMDF) problem.IMDF problem can be described as: how to change the capacity vector of a dynamic network as little as possible so that a given feasible dynamic flow becomes a maximum dynamic flow.After discussing some characteristics of this problem,it is converted to a constrained minimum dynamic cut problem.Then an efficient algorithm which uses two maximum dynamic flow algorithms is proposed to solve the problem.
The Lock Scheduling Problem (Het sluisplanningsprobleem)
Verstichel, Jannes
The present thesis introduces the lock scheduling problem and promising decompositions into sub problems. Several combinatorial optimization methods have been developed for the lock scheduling problem. Single and parallel chamber locks and lock operations in both an inland and mixed-traffic setting are considered, and a mathematical model precisely describing the problem is presented.Three interrelated sub problems can be discerned: ship placement, chamber assignment and lockage operation sch...
Effects of problem characteristics, capturing problem structure and using analogies on high school students' success on problem-solving
Directory of Open Access Journals (Sweden)
Pedro GARCÍA GALLEGO
Full Text Available This study analyses the influence of academic level, academic itinerary, word problem's context and structure, capturing problem structure, and using analogies on problem-solving. A factorial design was used with one within-subjects variable and several between-subjects variables, which have been selected depending on the hypothesis in question. Two types of booklets containing two word problems and questions about capturing problem structure and using analogies in problem solving, were administered to a total of 181 grade-10 and grade-12 students. The results of non-parametric statistical tests showed that: a Academic level and academic itinerary are decisive variables in problem solving, b Capturing problem structure is needed to solve problems, but the use of analogies is not needed, and c Problems increase in difficulty when they have complex structure and low familiarity context.
DEFF Research Database (Denmark)
Knudsen, Sanne
In order to teach writing and to facilitate reflective learning, we need to know and to understand the actual writing and writing processes of our students - and in order to do so, we need research on what students think, want and write. Fostering critical thinking is one of the central aims...... of university, and during the last decades we have experienced a boom in student-oriented learning approaches specifically aiming at generating and supporting critical thinking and writing. As a result, new genres are born, in which students are expected to use and transform knowledge in a manner which...... is different from or even contradictory of their previous writing experiences. Or, as Maggi Savin-Baden concludes; "It is naïve to assume that it is possible to adopt problem-based learning with ease". Nevertheless, there is little research on students' generic competence in negotiating and constructing...
Isotropic bodies and Bourgain's problem
Institute of Scientific and Technical Information of China (English)
[1]Milman, V. D., Pajor, A., Isotropic position and inertia ellipsoid and zonoids of the unit ball of a normed ndimensional space, Geometric aspects of functional analysis (1987-1988), Lecture Notes in Math., 1989, 1376:64-104.[2]Blaschke, W., Uber affine Geometry ⅩⅣ: eine minimum Aufgabe fur Legendres tragheits Ellipsoid, Ber. verh.sachs. Akad. d. Wiss., 1918, 70: 72-75.[3]Blaschke, W., Uber affine Geometry Ⅺ: losing der "Vierpunkproblems" von Sylvester aus der Teorie der geometrischen Wahrsdeinlichkeiten, Leipziger Berichte, 1917, 69: 436-453.[4]John, F., Polar correspondence with respect to convex regions, Duke Math. J., 1937, 3(2): 355-369.[5]Lutwak, E., Yang, D., Zhang, G., A new ellipsoid associated with convex bodes, Duke. Math. J., 2000, 104:375-390.[6]Bourgain, J., On the distribution of polynomails on high dimensional convex sets, Geometric aspects of functional analysis (1989-1990), Lecture Notes in Math., 1991, 1469: 127-137.[7]Dar, S., Remarks on Bourgain's problem on slicing of convex bodies, Geomitric aspects of functional analysis,in Oper. Theory Adv. Appl., Vol, 77, Basel: Birkhauser, 1995, 61-66.[8]Ball, K., Normed spaces with a weak-Gordon-Lewis property, in: Proc. of Funct. Anal., University of Texas and Austin (1987-1989), Lecture Notes in Math., 1991, 1470: 36-47.[9]Schneider, R., Weil, W., Zonoids and related topics, in Convexity and Its Applications (eds. Gruber, P. M., Wills,J. M.), Basel: Birkhauser, 1983, 296-317.[10]Bourgain, J., Klartag, B., Milman, V., A reduction of the slicing problem to finite volume ratio bodies, Geometry/Functional Analysis, C. R. Acad. Sci. Paris, Ser. I, 2003, 336: 331-334.[11]Ren, D. L., An Introduction to Integral Geometry (in Chinese), Shanghai: Science and Technology Press, 1988.[12]Gardner, R. J., Geometric Tomography, Cambridge: Cambridge University Press, 1995.[13]Leichtweiβ, K., Affine Geometry of Convex Bodies, Heidelberg: J. A. Barth, 1998.[14]Schneider, R., Convex Bodies: The Brunn
Quantum geometrodynamics creates new problems
Shestakova, T P
The development of last years in quantum geometrodynamics highlights new problems which were not obvious in its first formulation proposed by Wheeler and DeWitt. At the first stage the main task was to apply known quantization schemes to gravitational field or a certain cosmological model. This way has led to the realization of the fact that a quantum description of the Universe is impossible without implicit or explicit indication to a reference frame presented by some medium, filling the whole Universe, with its own equation of state and thermodynamical properties. Thus the questions arise, should one seek for a "privileged" reference frame or consider all the variety of gauge conditions and appropriate solutions for the wave function? It is worth noting that thermodynamical properties of such a quantum Universe would also depend on a chosen reference frame to some extent. So, we need a self-consistent quantum theoretical and thermodynamical description of the Universe.
Field insulation materials and problems
Vogt, G. H.
In a turbine generator the rotating field requires insulation materials and design considerations much different from the high voltage insulation used for armature windings. The principal properties to be looked for are mechanical strength, resistance to abrasion and resistance to thermal degradation. Electrical strength is also important because field windings are required to withstand a high potential test of ten times rated voltage. Some of the materials used over the years ranged from various kinds of fibers and flake mica composites, to asbestos, fiberglass epoxy or polyester laminates, Nomex and combinations of fiberglass, Nomex and insulating films. New materials have been applied to satisfy demands for better properties as generators grew in size and output, and it is the new materials that have made it possible to obtain more power from smaller machines. Field insulation materials and problems are discussed further.
Institute of Scientific and Technical Information of China (English)
SONG Shaoyun; LI Shiqi
Collaborative design is recommendedto solve multiphysics problems (MPPS). Firstly,mathematical model of MPPS is constructed and solved by a proposed partitioned method, analysis of which suggests that collaborative design be feasible to solve MPPS. As the key technology of collaborative design of MPPS, a task collaboration algorithm is then proposed. To develop the application framework of collaborative design, applied unified process(AUP) is proposed based on rational unified process(RUP). Then AUP is used to develop the collaborative design platform, whose function framework is constructed according to the process of project management. Finally three MPPS are solved on this platform and the results suggest that the proposed model, algorithm and framework be feasible.
Neurological problems of jazz legends.
Pearl, Phillip L
A variety of neurological problems have affected the lives of giants in the jazz genre. Cole Porter courageously remained prolific after severe leg injuries secondary to an equestrian accident, until he succumbed to osteomyelitis, amputations, depression, and phantom limb pain. George Gershwin resisted explanations for uncinate seizures and personality change and herniated from a right temporal lobe brain tumor, which was a benign cystic glioma. Thelonious Monk had erratic moods, reflected in his pianism, and was ultimately mute and withdrawn, succumbing to cerebrovascular events. Charlie Parker dealt with mood lability and drug dependence, the latter emanating from analgesics following an accident, and ultimately lived as hard as he played his famous bebop saxophone lines and arpeggios. Charles Mingus hummed his last compositions into a tape recorder as he died with motor neuron disease. Bud Powell had severe posttraumatic headaches after being struck by a police stick defending Thelonious Monk during a Harlem club raid.
Adaptive sampling for noisy problems
Energy Technology Data Exchange (ETDEWEB)
Cantu-Paz, E
The usual approach to deal with noise present in many real-world optimization problems is to take an arbitrary number of samples of the objective function and use the sample average as an estimate of the true objective value. The number of samples is typically chosen arbitrarily and remains constant for the entire optimization process. This paper studies an adaptive sampling technique that varies the number of samples based on the uncertainty of deciding between two individuals. Experiments demonstrate the effect of adaptive sampling on the final solution quality reached by a genetic algorithm and the computational cost required to find the solution. The results suggest that the adaptive technique can effectively eliminate the need to set the sample size a priori, but in many cases it requires high computational costs.
Institute of Scientific and Technical Information of China (English)
Rapidly aging society will challenge China's future labor force HUANG Sanbi,65,once an accountant in a university in Beijing,has been retired for nearly 10 years.Her day is full and well scheduled.Doing morning exercises, studying ways of maintaining her health and having fun with the family have become her daily "obligatory courses." She is one of the lucky ones,leading a happy life in her old age,not worrying about things like pension and medical insurance. However,many senior citizens in rural areas or with medium and low income are not well prepared for their retirement.Problems caused by an aging population pose a big challenge to China's future development,despite its recent economic progress.
Quantum Simulations of Physics Problems
Somma, R D; Knill, E; Gubernatis, J; Somma, Rolando; Ortiz, Gerardo; Knill, Emanuel; Gubernatis, James
If a large Quantum Computer (QC) existed today, what type of physical problems could we efficiently simulate on it that we could not simulate on a classical Turing machine? In this paper we argue that a QC could solve some relevant physical "questions" more efficiently. The existence of one-to-one mappings between different algebras of observables or between different Hilbert spaces allow us to represent and imitate any physical system by any other one (e.g., a bosonic system by a spin-1/2 system). We explain how these mappings can be performed showing quantum networks useful for the efficient evaluation of some physical properties, such as correlation functions and energy spectra.
Optimization in HIV screening problems
Directory of Open Access Journals (Sweden)
Lev Abolnikov
Full Text Available In this article, the authors use both deterministic and stochastic approaches to the analysis of some optimization problems that arise in the group (pool HIV screening practice. Two kinds of testing policies are considered. For the first kind, group-individual testing, the optimal size of the group that should be selected for testing is found. For more general group-subgroup testing procedure the authors develop a numerical algorithm for finding the sequence of successively selected subgroups that minimizes the total cost of testing. Assuming that both arriving and testing processes have a random nature, the authors suggest a stochastic model in which the optimal size of the group in the group-individual testing procedure is found by using methods of queueing theory.
Splitting methods for Levitron Problems
Geiser, Juergen
In this paper we describe splitting methods for solving Levitron, which is motivated to simulate magnetostatic traps of neutral atoms or ion traps. The idea is to levitate a magnetic spinning top in the air repelled by a base magnet. The main problem is the stability of the reduced Hamiltonian, while it is not defined at the relative equilibrium. Here it is important to derive stable numerical schemes with high accuracy. For the numerical studies, we propose novel splitting schemes and analyze their behavior. We deal with a Verlet integrator and improve its accuracy with iterative and extrapolation ideas. Such a Hamiltonian splitting method, can be seen as geometric integrator and saves computational time while decoupling the full equation system. Experiments based on the Levitron model are discussed.
Heat exchanger leakage problem location
Directory of Open Access Journals (Sweden)
Jícha Miroslav
Full Text Available Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.
Heat exchanger leakage problem location
Hejčík, Jiří; Jícha, Miroslav
Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.
Embedding problems in symplectic geometry
Schlenk, Felix
Symplectic geometry is the geometry underlying Hamiltonian dynamics, and symplectic mappings arise as time-1-maps of Hamiltonian flows. The spectacular rigidity phenomena for symplectic mappings discovered in the last two decades show that certain things cannot be done by a symplectic mapping. For instance, Gromov''s famous "non-squeezing'''' theorem states that one cannot map a ball into a thinner cylinder by a symplectic embedding. The aim of this book is to show that certain other things can be done by symplectic mappings. This is achieved by various elementary and explicit symplectic embedding constructions, such as "folding", "wrapping'''', and "lifting''''. These constructions are carried out in detail and are used to solve some specific symplectic embedding problems. The exposition is self-contained and addressed to students and researchers interested in geometry or dynamics.