Sensor array

A sensor array is a group of sensors, usually deployed in a certain geometry pattern, used for collecting and processing electromagnetic or acoustic signals. The advantage of using a sensor array over using a single sensor lies in the fact that an array adds new dimensions to the observation, helping to estimate more parameters and improve the estimation performance.
For example an array of radio antenna elements used for beamforming can increase antenna gain in the direction of the signal while decreasing the gain in other directions, i.e., increasing signal-to-noise ratio (SNR) by amplifying the signal coherently. Another example of sensor array application is to estimate the direction of arrival of impinging electromagnetic waves.
The related processing method is called array signal processing. A third examples includes chemical sensor arrays, which utilize multiple chemical sensors for fingerprint detection in complex mixtures or sensing environments. Application examples of array signal processing include radar/sonar, wireless communications, seismology, machine condition monitoring, astronomical observations fault diagnosis, etc.
Using array signal processing, the temporal and spatial properties (or parameters) of the impinging signals interfered by noise and hidden in the data collected by the sensor array can be estimated and revealed. This is known as parameter estimation.
Plane wave, time domain beamforming.
Figure 1 illustrates a six-element uniform linear array (ULA). In this example, the sensor array is assumed to be in the far-field of a signal source so that it can be treated as planar wave.
Parameter estimation takes advantage of the fact that the distance from the source to each antenna in the array is different, which means that the input data at each antenna will be phase-shifted replicas of each other. Eq. (1) shows the calculation for the extra time it takes to reach each antenna in the array relative to the first one, where "c" is the velocity of the wave.
formula_1
Each sensor is associated with a different delay. The delays are small but not trivial. In frequency domain, they are displayed as phase shift among the signals received by the sensors. The delays are closely related to the incident angle and the geometry of the sensor array. Given the geometry of the array, the delays or phase differences can be used to estimate the incident angle. Eq. (1) is the mathematical basis behind array signal processing. Simply summing the signals received by the sensors and calculating the mean value give the result
formula_2 .
Because the received signals are out of phase, this mean value does not give an enhanced signal compared with the original source. Heuristically, if we can find delays of each of the received signals and remove them prior to the summation, the mean value
formula_3
will result in an enhanced signal. The process of time-shifting signals using a well selected set of delays for each channel of the sensor array so that the signal is added constructively is called beamforming.
In addition to the delay-and-sum approach described above, a number of spectral based (non-parametric) approaches and parametric approaches exist which improve various performance metrics. These beamforming algorithms are briefly described as follows.
Array design.
Sensor arrays have different geometrical designs, including linear, circular, planar, cylindrical and spherical arrays. There are sensor arrays with arbitrary array configuration, which require more complex signal processing techniques for parameter estimation. In uniform linear array (ULA) the phase of the incoming signal formula_4 should be limited to formula_5 to avoid grating waves. It means that for angle of arrival formula_6 in the interval formula_7 sensor spacing should be smaller than half the wavelength formula_8. However, the width of the main beam, i.e., the resolution or directivity of the array, is determined by the length of the array compared to the wavelength. In order to have a decent directional resolution the length of the array should be several times larger than the radio wavelength.
Delay-and-sum beamforming.
If a time delay is added to the recorded signal from each microphone that is equal and opposite of the delay caused by the additional travel time, it will result in signals that are perfectly in-phase with each other. Summing these in-phase signals will result in constructive interference that will amplify the SNR by the number of antennas in the array. This is known as delay-and-sum beamforming. For direction of arrival (DOA) estimation, one can iteratively test time delays for all possible directions. If the guess is wrong, the signal will be interfered destructively, resulting in a diminished output signal, but the correct guess will result in the signal amplification described above.
The problem is, before the incident angle is estimated, how could it be possible to know the time delay that is 'equal' and opposite of the delay caused by the extra travel time? It is impossible. The solution is to try a series of angles formula_9 at sufficiently high resolution, and calculate the resulting mean output signal of the array using Eq. (3). The trial angle that maximizes the mean output is an estimation of DOA given by the delay-and-sum beamformer.
Adding an opposite delay to the input signals is equivalent to rotating the sensor array physically. Therefore, it is also known as beam steering.
Spectrum-based beamforming.
Delay and sum beamforming is a time domain approach. It is simple to implement, but it may poorly estimate direction of arrival (DOA). The solution to this is a frequency domain approach. The Fourier transform transforms the signal from the time domain to the frequency domain. This converts the time delay between adjacent sensors into a phase shift. Thus, the array output vector at any time "t" can be denoted as formula_10, where formula_11 stands for the signal received by the first sensor. Frequency domain beamforming algorithms use the spatial covariance matrix, represented by formula_12. This "M" by "M" matrix carries the spatial and spectral information of the incoming signals. Assuming zero-mean Gaussian white noise, the basic model of the spatial covariance matrix is given by
formula_13
where formula_14 is the variance of the white noise, formula_15 is the identity matrix and formula_16 is the array manifold vector formula_17 with formula_18. This model is of central importance in frequency domain beamforming algorithms.
Some spectrum-based beamforming approaches are listed below.
Conventional (Bartlett) beamformer.
The Bartlett beamformer is a natural extension of conventional spectral analysis (spectrogram) to the sensor array. Its spectral power is represented by
formula_19.
The angle that maximizes this power is an estimation of the angle of arrival.
MVDR (Capon) beamformer.
The Minimum Variance Distortionless Response beamformer, also known as the Capon beamforming algorithm, has a power given by
formula_20.
Though the MVDR/Capon beamformer can achieve better resolution than the conventional (Bartlett) approach, but this algorithm has higher complexity due to the full-rank matrix inversion. Technical advances in GPU computing have begun to narrow this gap and make real-time Capon beamforming possible.
MUSIC beamformer.
MUSIC (MUltiple SIgnal Classification) beamforming algorithm starts with decomposing the covariance matrix as given by Eq. (4) for both the signal part and the noise part. The eigen-decomposition of is represented by
formula_21.
MUSIC uses the noise sub-space of the spatial covariance matrix in the denominator of the Capon algorithm
formula_22.
Therefore MUSIC beamformer is also known as subspace beamformer. Compared to the Capon beamformer, it gives much better DOA estimation.
SAMV beamformer.
SAMV beamforming algorithm is a sparse signal reconstruction based algorithm which explicitly exploits the time invariant statistical characteristic of the covariance matrix. It achieves superresolution and robust to highly correlated signals.
Parametric beamformers.
One of the major advantages of the spectrum based beamformers is a lower computational complexity, but they may not give accurate DOA estimation if the signals are correlated or coherent. An alternative approach are parametric beamformers, also known as maximum likelihood (ML) beamformers. One example of a maximum likelihood method commonly used in engineering is the least squares method. In the least square approach, a quadratic penalty function is used. To get the minimum value (or least squared error) of the quadratic penalty function (or objective function), take its derivative (which is linear), let it equal zero and solve a system of linear equations.
In ML beamformers the quadratic penalty function is used to the spatial covariance matrix and the signal model. One example of ML beamformer penalty function is
formula_23 ,
where formula_24 is the Frobenius norm. It can be seen in Eq. (4) that the penalty function of Eq. (9) is minimized by approximating the signal model to the sample covariance matrix as accurate as possible. In other words, the maximum likelihood beamformer is to find the DOA formula_6, the independent variable of matrix formula_26, so that the penalty function in Eq. (9) is minimized. In practice, the penalty function may look different, depending on the signal and noise model. For this reason, there are two major categories of maximum likelihood beamformers: Deterministic ML beamformers and stochastic ML beamformers, corresponding to a deterministic and a stochastic model, respectively.
Another idea to change the former penalty equation is the consideration of simplifying the minimization by differentiation of the penalty function. In order to simplify the optimization algorithm, logarithmic operations and the probability density function (PDF) of the observations may be used in some ML beamformers.
The optimizing problem is solved by finding the roots of the derivative of the penalty function after equating it with zero. Because the equation is non-linear a numerical searching approach such as Newton–Raphson method is usually employed. The Newton–Raphson method is an iterative root search method with the iteration
formula_27.
The search starts from an initial guess formula_28. If the Newton-Raphson search method is employed to minimize the beamforming penalty function, the resulting beamformer is called Newton ML beamformer. Several well-known ML beamformers are described below without providing further details due to the complexity of the expressions.


Kenya National Examinations Council

The Kenya National Examinations Council (KNEC) is the national body responsible for overseeing national examinations in Kenya. Its current chairman is Professor John Onsati. This council was established under the Kenya National Examinations Council Act Cap 225A of the Laws of Kenya, in 1980. In 2012 this act was repealed in 2012 and replaced with KNEC Act No.29 of 2012.
The KNEC was established to conduct school, post school and other examinations after the dissolution of East African Examinations Council and the Ministry of Education [EAEC and ME]. After the dissolution of EAEC and the ME the Kenya National Examinations Council took the roles of ensuring validity and reliability of examinations; and to ensure conformity to Kenya's goals and changes in government policy relating to the curriculum and examinations.
Functions.
The functions of the Kenya National Examinations Council are as follows:
Core functions.
The core functions of the examination body are:
Examinations.
Some of the exams delivered by KNEC are:


Jane Blankenship

Jane Blankenship won high science honors while at Oak Ridge High School before graduating in June 1958 from the University of Tennessee, Knoxville with a B.S. in chemistry. She worked summers at Oak Ridge National Laboratory, where her father Dr. Forrest F. Blankenship was a physical chemist, and then married Carl H. Gibson, a chemical engineer, and became employed as a spectroscopist for Lockheed Research Laboratory in Palo Alto, California.
Life and Times.
Jane Carruth Blankenship and twin sister Elizabeth Ann Blankenship were born on June 20, 1936 in Paris, Texas to Forrest Farley Blankenship and Margaret Berry Burke.
Forrest Blankenship entered college at the age of 14 and had obtained his Bachelor and Master of Science degrees at the University of Texas by the age of 19. He then became head of the sciences department at Paris Junior College. He alternately taught at PJC to support his young family and pursued graduate studies at the University of Chicago and University of Texas. He earned his Doctor of Philosophy degree in physical chemistry at the University of Texas in Austin in 1943. Margaret Burke was a hometown Paris girl who was a student and valedictorian at Paris Junior College. The pair met on the tennis courts which led to romance, marriage and a lifetime of tennis rivalry.
The family moved to Norman Oklahoma where Dr. Blankenship joined the faculty in the chemistry department. Jane enjoyed the articles in Science News available in her classroom and at age 7 decided she wanted to become a scientist. She loved to read and learn everything she could about the sciences and whenever her schools offered a Science Fair she developed and entered a project.
When Jane was age 15 Dr. Blankenship accepted a position at Oak Ridge National Laboratory, Oak Ridge, TN. As a senior at Oak Ridge High School Jane was a winner of the regional science fair and a finalist at the National Science Fair in 1954. She also entered the Westinghouse Science Talent Search and won honorable mention in the national competition. The application included conducting a research project at home, writing a scientific paper and taking nationally competitive exam.
Jane attended University of Tennessee and graduated in 1958 with a major in physical chemistry and a minor in math. During her undergraduate years, Jane worked summers at Oak Ridge National Laboratory.
Jane married Carl H. Gibson on May 31, 1958 and they went to Palo Alto, CA. Carl pursued graduate studies at Stanford University in the chemical engineering department studying turbulent mixing on a National Engineering fellowship (post sputnik).
Jane accepted a position at Lockheed Research Laboratory adjacent to the Stanford campus. There she performed spectroscopic studies of species in high temperature air using a shock tube. Soon she enrolled in a master's program at Stanford because she wanted to study quantum mechanics and continued to work at Lockheed.
Jane and Carl were very interested in President Kennedy's proposal to start the Peace Corps. They took the application screening test when it was first offered. To their surprise they were invited to be in the first Peace Corps group to be fielded (Ghana). This was in April 1962 and they were still in the middle of getting their theses approved. They had to decline saying they would not be available until June. The Peace Corps responded with an assignment to Hyderabad, India where they would be lecturers at Osmania University.
In June 1962 Carl received his PhD in chemical engineering and Jane graduated with an MS in physical sciences. They set off immediately for two months of Peace Corps training at the University of Illinois. Carl and Jane value the two-year experience in India and knew once they were immersed with jobs and children the opportunity would be lost.
After a lengthy journey home from India (crossed the Indian Ocean on a freighter during Monsoon season, tour of East Africa by jeep, down the Nile River by paddle wheel boat, Egypt, Europe from Greece to the top of Finland) Carl visited many campuses and applied for post docs. They selected University of California San Diego (UCSD) which was just being formed (some graduate students but no undergraduates when they arrived in January 1965).
Time to start the family. Greg arrived March 1965 and sister Robin 19 months later in Dec 1966. Jane chose to enjoy parenting and took a hiatus from her career. Greg became a civil engineer and Robin earned a PhD in biochemistry at UCSD. Carl and Jane divorced in 1974.
Jane became a Staff Research Associate in Professor Donald Helinski's molecular biology lab at UCSD in 1975. There she learned to use restriction enzymes to delete and add genes to plasmid DNA in E-coli bacteria. In those days it was called "recombinant DNA".
In 1979 Jane transferred to General Atomics with the title Senior Scientist. She spent the rest of her career at GA working on various energy, fission and fusion research contracts.
Jane retired in June 2007 and is happily playing in San Diego. She is a photography enthusiast. She attends several lectures each week at UCSD under the auspices of the Osher Life-Long Learning Institute. She enjoys reading various journals to stay abreast of the latest science developments. Yes, she still reads Science News and is a fan of Tom Sigfried. Science Service has played an influential role in her life!
Hobbies have included scuba diving and a lot of tennis. Jane was always at home when backpacking in her beloved Sierra Nevada Mountains. Walking, hiking and camping in the wilderness is still a favorite pass time.
National Attention
In 1961, a news story was written regarding "sex desegregation" in the sciences and a photograph of her was utilized to illustrate the critical significance of inspiring women to pursue careers in science.
As of 2008 Professor David Kaiser of the Massachusetts Institute of Technology began offering a graduate level course titled "Cold War Science" that discussed the role women featured during the Cold War and included Jane Blankenship Gibson as an example.


Resonator dulcimer

The resonator dulcimer is an Appalachian dulcimer which features a metal resonating cone inset in the body, which receives and acoustically amplifies the vibration of the strings. The first instrument was conceived in 1977 and completed in 1979 by dulcimer luthier Homer Ledford, who called it a "dulcibro" (portmanteau of "dulcimer" and "dobro").
Unlike resonator guitars, resonator ukuleles, and resonator mandolins, the resonator dulcimer was never commercially produced on a large scale.


Debbie Dupuis

Debbie Janice Dupuis is a Canadian statistician who works in decision science and robust statistics with applications to statistical finance and environmental statistics. She is a professor in the Department of Decision Sciences at HEC Montréal.
Education and career.
Dupuis grew up in Memramcook, New Brunswick, and graduated from the Université de Moncton in 1989 with a bachelor's degree in mathematics and a minor in computer science. With the support of an NSERC graduate fellowship, she earned a master's degree in mathematics and statistics from Queen's University. She completed her Ph.D. in 1994 from the University of New Brunswick. Her dissertation, "Knots in Spline Regression: Estimation and Inference Using Laplace Transform Techniques", was supervised by Roman Mureika, and won the Governor General's Gold Medal. She was a faculty member at Dalhousie University and Western University before moving to HEC Montréal.
Recognition.
In 2012 the Université de Moncton gave Dupuis their "Le Prisme" award as a distinguished alumna in the sciences. In 2017 Dupuis was elected as a Fellow of the American Statistical Association "for outstanding contributions to the analysis of extreme values and the development of robust statistical methods; for designing and promoting the use of innovative statistical analysis techniques in a broad array of substantive fields, most notably the environmental sciences, finance and hydrology; and for dynamic and sustained involvement in editorial and organizational service to the profession".


Tempore

Tempore (abbreviated to temp.), in historical literature, denotes a period during which a person whose exact lifespan is unknown, was known to have been alive or active, or some other date which is not exactly known, usually given as the reign of a monarch. The word is Latin, being the ablative singular of the noun "tempus, temporis", "time", thus meaning "in the time (of)". It should be followed by a name in the genitive case. The theoretical full form might be "vixit tempore Regis Henrici Primi" ("he/she lived in the time of King Henry the First") (i.e. 1100-1135).
The best known occurrence is in the Domesday Book of 1086, where the phrase "Tempore Regis Eduardi" (nominative case "Rex Eduardus"), meaning "in the time of King Edward (the Confessor)" appears in the entry for almost every manor, abbreviated as TRE. It thus signifies the date range 1042–1066. It is useful in historical literature because the names of many historical persons appear in surviving documents only in royal charters, possibly as witnesses, which can be dated to the reign of the originating monarch.
The word "tempore" is often given in its abbreviated form "temp." It is similar to "floruit" ("flourished" [at a date or range of dates]) which however is more appropriate for artists to denote not merely a period of life, but a particularly productive period within that lifespan.


3085 Donna


Lausanne Underground Film and Music Festival

The Lausanne Underground Film and Music Festival (LUFF) is a film festival and music festival devoted to underground film and music. It is held each year in Lausanne, Switzerland. The festival is organized by a non-profit organization (APCI – Association pour la Promotion de la Culture Indépendante). The organization's goals are to promote independent artistic projects and creations and to make those projects accessible to a large public. The primary goal of the Lausanne Underground Film & Music Festival is to present films and music that largely exist outside the mainstream and profit driven production and distribution circuits. The cinematic section presents mainly films with an experimental character and/or films that challenge the spectator's viewing habits. Films are screened during the day and evening, followed by live music events featuring underground artists at night. Money prizes are awarded by the festival for the films selected in the international competition, in order to support the filmmakers in creating their art. The musical program of the festival proposes sonar experimentations of all kind.
During the four concert nights of the festival week, an average of twenty international and Swiss musicians and groups play in the Salle des Fêtes of the Casino de Montbenon, the neuralgic center of the festival. In 2012 the festival has considerably enlarged its "off" program (a wide artistic offer free of charge, evolving in parallel to the official program) which continues to grow ever since and participates largely to the festive and open character of the event.During the five days of the festival, its activities also expand to local venues such as the rock club Le Romandie, the independent movie theater Le Zinéma, the cultural venue La Datcha, the auditorium of the local music school EJMA as well as the book store and art gallery La Librairie Humus, the art gallery Standard Deluxe, the associative photo&cine laboratory "on fait du l'art !", the independent movie theater Bellevaux and use to work with the café-théâtre le Bourg and the center for contemporary art Arsenic.The annual budget of the festival is of total value about 300.000 Swiss francs (270,000 euros).
History of the festival.
Originally called "Underground Nights", the festival drew its inspiration from the New York Underground Film Festival. Through its initial, formative years, though, the LUFF developed its own unique program. Starting in its first year with a small screening room that could seat only 30 people, the festival managed to gather more than 1,000 spectators in 2000. In 2002, after a one-year hiatus, the festival moved to Lausanne with the support of the Swiss Film Archive, for the first official edition of the "Lausanne Underground Film and Music Festival", drawing 4,000 spectators. By 2013, the festival has drawn around 8000 spectators. By programming an international short and feature films competition while still paying homage to great names of the underground like Nick Zedd, John Waters, Lloyd Kaufman, Ian Kerkhof, Kenneth Anger and the Kuchar brothers; and by organizing musical events featuring such artists as Jimi Tenor, Hanin Elias, Techno Animal, Chicks on Speed, Rhys Chatam, Pansonic and Alan Vega, the LUFF programming now stretches beyond the Swiss borders.
Festival Editions.
2016: The Fifteenth Edition.
Will be held from October 19 to 23 2016 in Lausanne.
2015: The Fourteenth Edition.
Held from October 14 to 18 2015, it has attracted around 13'000 spectators during the five days of film screenings and four concert nights. Among the retrospective programs one dedicated to filmmaker Jeff Perkins presented his "Movies for the Blind", a series of intensive recordings of interviews with passengers in his yellow cab from 1995 to 2002.
2014: The Thirteenth Edition.
Was held from 15 to 19 October 2015.
2013: The Twelfth Edition.
The twelfth edition of the festival (October 16 to 20 2013) featured a total of 98 films. Retrospective programs featured works by Japanese surrealist filmmaker Katsu Kanai, French actor-filmmaker Pierre Clémenti, French punk author, musician and filmmaker F. J. Ossang, Russian independent filmmaker Andrey Iskanov, Polish filmmaker Walerian Borowczyk and Belgian filmmaker Marcel Broodthaers as well as a carte blanche program to Jello Biafra. The international film competition included five feature films and 18 short films. The music part included 24 concerts for the total of four concert nights. The program presented sets by artists such as Emptyset, Endon, The Haxan Cloak, Vomir, Kracoon, Sugar Craft, Sajjanu, Jello Biafra, Fen (Far East Network: Otomo Yoshihide, Ryu Hankil, Yuen Chee Wal, Yan Jun), Nate Young, Blackphone666, Aluk Todolo, Jason Lescalleet, JG Thirwell, Bryan Lewis Saunders, Leif Elggren, Jean-François Laporte, Evil Moisture, Smegma, Nicolas Bernier & Martin Messier, Kiko C. Esseiva and DJ Nozinja. A total of 58 artists (musicians and filmmakers) were present during the five days of the festival to present their works.
The twelfth edition of the Lausanne Underground Film & Music Festival also proposed a range of workshops, aiming to introduce spectators to new or little known artistic techniques. The five workshops were held by artists such as the South-African group Shangaan Dance, Japanese decoupage artist Kosuke Kawamura, Canadian experimental musician Jean-François Laporte, Japanese noise musician Endon and French musician and artist Andy Bolus.
The program of the festival also included an off part featuring the festival's own radio station (LUFF.FM), expositions and various artistic performances all through the five days of the festival.
2012: The Eleventh Edition.
For the eleventh edition of the festival (October 17–21, 2012) John Waters was invited to present his one Man show "This Filthy World", a vaudeville act that celebrates his film career and obsessional tastes, and to present a retrospective of four of his early films as well as a selection of four of his favorite films. Other retrospectives included works by Austrian filmmaker and writer Christoph Schlingensief, Richard Stanley and Dutch provocateur Edwin Brienen. The international competition included five feature films and 28 short films. 21 musical performances were held during the four concert nights, featuring artists such as Pain Jerk, Brutal Truth, Fat32, rm, Blectum From Blechdom, Kim Gordon, Bill Nace, Maja S. K. Ratkje, Ikue Mori, Greg Pope, Gilles Aubry, Radian, Cellule d'Intervention Metamkine, Kevin Drumm, Thomas Ankersmit, Michael Esposito, Mattin, Zeni Geva, Arcangel Constantini, Yan Jun.
2012: LUFF does TOKYO / FEEDBACK TOKYO.
At the occasion of the tenth edition, the festival held a special anniversary edition in Tokyo, Japan through an exchange program line-up between the festival, the livehouse Super-Deluxe (Tokyo) and the team of dEnOISE events, Uplink Factory and Image Forum Festival. This one time only exchange was held from April 27 to May 4, 2012 and featured movies from Peter Liechti, Emmanuelle de Riedmatten, Stephan E. Hauser among many others. A website in Japanese, English and French was made for the occasion : http://tokyo.luff.ch.
2011: The Tenth Edition.
The tenth edition of the festival was held from October 19 to 23 2011.
2010: The Ninth Edition.
The tenth edition of the festival was held from October 20 to 24 2010.
2009: The Eighth Edition.
This edition was held from October 14 to 18 2009
2008: The Seventh Edition.
Held from October 15 to 19 2008.
2007: The Sixth Edition.
Held from October 10 to 14 in Swiss Film Archive, Arsenic and Zinéma.
2006: The Fifth Edition.
The fifth edition of LUFF (October 11–15, 2006) featured a look at Viennese Actionism, a retrospective on Jonas Mekas, a program titled "sXprmntl" selected by Roland Lethem with films by Thierry Zéno, Philippe Caufriez, Patrice Bauduinet, and Patrick Hella, as well as a series by Jean-Jacques Rousseau. Musical events included Genesis P-Orridge, Lydia Lunch, John Duncan, The Haters, Gabi Delgado, Kid 606, Spectre, and more.
2005: The Fourth Edition.
October 12 to 16 2005
2004: The Third Edition.
October 13 to 17 2004
2003 : The Second Edition.
October 8 to 12 2003
2002: The First Edition.
The first edition of the festival was held from June 5 to 9 2002.


Rongwei Fu

Rongwei (Rochelle) F. Fu is a biostatistician who uses meta-analysis to understand disease incidence, detection, and treatment.
She is a professor of biostatistics, medical informatics and clinical epidemiology at the Oregon Health & Science University (OHSU), and the director of biostatistics education at OHSU.
She has also worked as lead biostatistician for the OHSU Center for Policy and Research in Emergency Medicine (CPR-EM), at the Pacific Northwest Evidence-based Practice Center (EPC), and at the OHSU Research Center for Gender-Based Medicine.
After earning a master's degree at Shandong Normal University in Jinan, China, in 1995, Fu came to the US for additional graduate study. She earned two doctorates at the University of Connecticut, one in plant science in 2000 and a second one in statistics in 2003. Her second dissertation, supervised by Dipak K. Dey, was "Probabilistic Structure and Statistical Inference for Nonexplicit Population Models and Allele Frequency".
She was elected as a Fellow of the American Statistical Association in 2017.


Exact test

In statistics, an exact (significance) test is a test where if the null hypothesis is true then all assumptions, upon which the derivation of the distribution of the test statistic is based, are met. Using an exact test provides a significance test that keeps the Type I error rate of the test (formula_1) at the desired significance level of the test. For example an exact test at significance level of formula_2, when repeating the test over many samples where the null hypotheses is true, will reject at most formula_3 of the time. This is opposed to an "approximate test" in which the desired type I error rate is only approximately kept (i.e.: the test might reject more than 5% of the time), while this approximation may be made as close to formula_1 as desired by making the sample size big enough.
Exact tests that are based on discrete test statistic may be conservative tests, i.e. that its actual rejection rate is below the nominal significance level formula_1. For example, this is the case for Fisher's exact test and also its more powerful alternative, Boschloo's test. If the test statistic is continuous, it will reach the significance level exactly .
Parametric tests, such as those described in exact statistics, are exact tests when the parametric assumptions are fully met, but in practice the use of the term "exact" (significance) "test" is reserved for those tests that do not rest on parametric assumptions – non-parametric tests . However, in practice most implementations of non-parametric test software use asymptotical algorithms for obtaining the significance value, which makes the implementation of the test non-exact.
So when the result of a statistical analysis is said to be an “exact test” or an “exact p-value”, it ought to imply that the test is defined without parametric assumptions and evaluated without using approximate algorithms. In principle however it could also mean that a parametric test has been employed in a situation where all parametric assumptions are fully met, but it is in most cases impossible to prove this completely in a real world situation. Exceptions when it is certain that parametric tests are exact include tests based on the binomial or Poisson distributions. Sometimes permutation test is used as a synonym for exact test, but although all permutation tests are exact tests, not all exact tests are permutation tests.
Exact tests.
The basic equation underlying exact tests is
where:
and where the sum ranges over all outcomes y (including the observed one) that have the same value of the test statistic obtained for the observed sample x, or a larger one .
Example: Pearson's chi-squared test versus an exact test.
A simple example of the occasion for this concept may be seen by observing that Pearson's chi-squared test is an approximate test. Suppose Pearson's chi-squared test is used to ascertain whether a six-sided die is "fair", i.e. gives each of the six outcomes equally often. If the die is thrown "n" times, then one "expects" to see each outcome "n"/6 times. The test statistic is
where "X""k" is the number of times outcome "k" is observed. If the null hypothesis of "fairness" is true, then the probability distribution of the test statistic can be made as close as desired to the chi-squared distribution with 5 degrees of freedom by making the sample size "n" big enough. But if "n" is small, then the probabilities based on chi-squared distributions may not be very close approximations. Finding the exact probability that this test statistic exceeds a certain value then requires combinatorial enumeration of all outcomes of the experiment that result in such a large value of the test statistic. Moreover, it becomes questionable whether the same test statistic ought to be used. A likelihood-ratio test might be preferred as being more powerful, and the test statistic might not be a monotone function of the one above.
Example: Fisher's exact test.
Fisher's exact test, based on the work of Ronald Fisher and E. J. G. Pitman in the 1930s, is exact because the sampling distribution (conditional on the marginals) is known exactly. Compare Pearson's chi-squared test, which (although it tests the same null) is not exact because the distribution of the test statistic is correct only asymptotically.


RPE2

RPE2, or Relative server Performance Estimate 2, is a computer benchmark developed by Ideas International to compare the relative performance of servers built on x86, IA-64, and RISC processor architectures.
The benchmark is a composite of results, or estimated results, from the SAP SD Standard Application Two-Tier benchmark, TPC-C, TPC-H, SPECjbb2005, SPECint, and SPECfp benchmarks. The benchmark was created in 2005, replacing an earlier benchmark called RPE.
RPE2 data is incorporated into some server capacity planning tools, such as
the ATS Server Consolidation Monitor from IBM and Data Center Intelligence software from CIRBA.


3007 Reaves


The Design of Experiments

The Design of Experiments is a 1935 book by the English statistician Ronald Fisher about the design of experiments and is considered a foundational work in experimental design. Among other contributions, the book introduced the concept of the null hypothesis in the context of the lady tasting tea experiment. A chapter is devoted to the Latin square.
Quotations regarding the null hypothesis.
Fisher introduced the null hypothesis by an example, the now famous Lady tasting tea experiment, as a casual wager. She claimed the ability to determine the means of tea preparation by taste. Fisher proposed an experiment and an analysis to test her claim. She was to be offered 8 cups of tea, 4 prepared by each method, for determination. He proposed the null hypothesis that she possessed no such ability, so she was just guessing. With this assumption, the number of correct guesses (the test statistic) formed a hypergeometric distribution. Fisher calculated that her chance of guessing all cups correctly was 1/70. He was provisionally willing to concede her ability (rejecting the null hypothesis) in this case only. Having an example, Fisher commented:
Regarding an alternative non-directional significance test of the Lady tasting tea experiment:
Regarding which test of significance to apply:
On selecting the appropriate experimental measurement and null hypothesis:


3734 Waland


Just minor third


4839 Daisetsuzan


Comparison of split testing tools

Performing split testing on a website requires a combination of features. There are many tools that make it easier to rotate variants and report results, yet they have many differences.


Orders of magnitude (bit rate)

An order of magnitude is generally a factor of ten. A quantity growing by four orders of magnitude implies it has grown by a factor of 10000 or 104. However, because computers are binary, orders of magnitude are sometimes given as powers of two.
This article presents a list of multiples, sorted by orders of magnitude, for bit rates measured in bits per second. Since some bit rates may measured in other quantities of data or time (like MB/s), information to assist with converting to and from these formats is provided. This article assumes the following:
Accordingly:


Acsensorize

Acsensorize ("v.t."), pronounced as ac-sensor-ize, is act of adding a multitude of dissimilar sensors, generally of a variety of sensing modalities, to an existing system that may or may not already have sensors;
It was first used by researchers at General Motors Global Research and Development, and was published in. The word was motivated by "accessorize". Acsensorizing plays a significant role in big data research and machine learning.


3587 Descartes


Video-in video-out

Video in video out (usually seen as the acronym VIVO , commonly pronounced ( VEE-voh), is a graphics port which enables some video cards to have bidirectional (input and output) analog video transfer through a mini-DIN connector, usually of the 9-pin variety, and a specialised splitter cable (which can sometimes also transfer analog audio).
VIVO was found on high-end ATI and NVIDIA computer video cards, sometimes labeled "". VIVO on these graphics cards typically supports composite, component, and S-Video as outputs, and composite and S-Video as inputs. Many other video cards only support component and/or S-Video outputs to complement VGA or DVI, typically using a component breakout cable and an S-Video cable. While component-out operation supports high-definition resolutions, it does not support the HDCP standard which would be required for official HDTV support as set out by the EICTA.
Some practical uses of VIVO include being able to display multimedia stored on a computer on a TV, and being able to connect a DVD player or video game console to a computer while continuing to allow viewing via a TV monitor. VIVO itself, however, can not decode broadcast signals from any source, and so, like HDTV sets without tuners and composite monitors, additional equipment is required to be able to show broadcast TV programs.
Some manufacturers enable their version of the VIVO port to also transfer sound.
Limitations.
The VIVO output on graphics cards is often not used by those who have no need to connect their computer to a TV. Also, there can be issues in software supporting the use of VIVO ports.
A computer using VIVO must have software that can handle an input signal. For example, in the case of Nvidia GeForce series 6 and 7 video card users this means downloading Nvidia's WDM drivers.
Additionally, On Windows XP computers that use GeForce video cards with Scalable Link Interface (SLI) mode enabled, using a TV to display part of the desktop via VIVO is disabled, just as dual-monitor mode is disabled. Confusingly, however, some distorted images may be visible on a properly-connected VIVO-driven television display at boot-up due to the fact that prior to the OS loading the display driver, the video bios might initialize outputs that are then unavailable once the OS takes over and the driver loads into SLI mode.


828 Lindemannia

828 Lindemannia is a minor planet orbiting the Sun with an orbital period of five years and 255 days. It was discovered on 29 August 1916 at the University of Vienna by Johann Palisa. It is named after Adolph Friedrich Lindemann, a British astronomer, engineer and businessman.


355 Gabriella

Gabriella (minor planet designation: 355 Gabriella) is a typical Main belt asteroid.
It was discovered by Auguste Charlois on 20 January 1893 in Nice and named after French astronomer Gabrielle Renaudot Flammarion.


Picture arrangement test

Picture arrangement test is a test that consists of a series of comic-strip-like pictures that are presented in a random order. The subject is given the task to arrange the pictures as quickly as possible so that a reasonable and meaningful story is formed. This is an example of a common feature found in intelligence tests. As the demand for psychological testing has increased, this type has seen increased use throughout Psychology. There are several different ways and scales that can be used with this test to measure different kind of intelligence. Different tests over time have been created to measure different things. One scale that has been developed and used with these tests has been the Wechsler Adult Intelligence Scale which breaks down ones full performance IQ into subsets like verbal IQ and performance IQ, getting more specific and elaborate as the scale for each individual develops. The reliability of this test has been disputed, however. For example, patients suffering from schizophrenia have been found to score as more "normal" than patients with no such mental disorders.
Historical Overview.
An article in 1917 written by Alida Bowler talked about the picture arrangement test designed to measure logical judgments that was tried by Dr. O. Decroly with five hundred school children in Brussels. His material consisted of eleven series of pictures taken from children's books, each series tell a complete simple story when arranged in the right order. The series are given to the child in a random order and requested that the child arrange them in a way that they tell a continuous story. His aim was to find series that adapted to different ages and he concluded that series of such tests will approximately indicate the mental age of who takes the test. In 1915, Alida and her co-examiners obtained copies of the “Foxy Grandpa” picture series which has a total of fifteen series with each story containing six scenes. The results of the experiment is described in the article and six picture series were dropped from the original fifteen for various reasons not specified in the article.
In 1939, David Wechsler realized the limitation of the Stanford-Binet and designed an intellect by tapping a diverse sample of capabilities. In earlier methods of assessment, Weschler devised the format that we currently known as the Wechsler scales, consisting of a collection of subsets. He believed in the unitary nature of intelligence but subscribed to the idea that intellect can be best measured through interdependent, qualitatively different abilities. Historical, the picture arrangement subsets of the Wechsler scales have been characterized repeatedly as being nonverbal and verbal measure of social competence. For this reason, clinicians interpret performance on the picture arrangement subsets as measures of social ability.
Although picture arrangement (PA) has been viewed as predictive of social intelligence, there has been considerable difficulty defining social intelligence, social functioning and/or social competence. Wechsler believed that general intelligence could be applied to all situations. Thus, “social” intelligence might best be conceptualized as one aspect of general intelligence.
Thorndike (1920) described social intelligence as the ability to understand others and “act wisely in human relations”. He proposed that social intelligence was itself an aspect of a person's IQ. More recent authors within the intelligence literature have also attempted to define social intelligence but have not succeeded in clarify the concept.
Weschler's Picture Arrangement (PA) Subset.
The PA subset includes “a set of colorful pictures, presented in a mixed-up order, which the child rearranges into a logical story sequence”. This subset is thought to measure the child's ability to anticipate the consequences of initial acts or situations, as well as the ability to interpret social situations. It is widely assumed that the PA subset measure a person's ability to evaluate and comprehend a situation using pictorial cues that have been visually organized. When performance is poor, it is suspected that the client may have an impaired capacity to reflect, anticipate, and plan a course of action, and to understand antecedent and consequent events. Since the PA items typically involve human or practical situations, it is also thought that a person with a high PA score is adept at sizing up and comprehending social situations. For example, it was common to attribute the high PA score found for adults diagnostically classified as narcissistic to their “Characteristically facile social anticipation”. Furthermore, adults with psychopathic character disorders frequently have a very high PA score, especially the “shrewd schemer” who can quickly evaluate a situation and manipulate it for his/her own end.
"Tomkins-Horn Picture Arrangement test".
The Tomkins-Horn Picture Arrangement test was conducted and created by Silvan Tomkins and Daniel Horn at the Harvard Psychology Clinic in 1942 as a subset the Wechsler intelligence scales, wherein the involved party must appropriately order a sequence of sketches which tell a short story in a very similar manner to the PAT developed by Tomkins and Horn. The PAT was inspired by The Thematic Apperception test and was developed to 'maximize the ease of administration and the scoring at the least cost in richness of projective material'. It was also developed for group testing and machine scoring. The test is designed to be given in random order to the subject where the subject is presented with a series of cards in an incorrect order that must be placed in the correct order to tell a story that makes sense. The stories are like short comic strips and placing them in order relies on the individual's ability to recognize the cause and effect relationship of events depicted in the cards. This task gives information about an individual's reasoning abilities, and performance is related to the ability to understand precursors and consequences of events. The pictures on the cards involve human characters and interactions and there are different keys which have been pre-determined. The subject tell matches a key which then gives information about the subject's intelligence and mental state.
The PAT developed by Silvan Tomkins and Daniel Horn had 25 plates each consisting of line drawings of three situation that were different but related. Each plate, and all 25 plates depicted a common “hero” in all the situations presented. It was the subject's task to specify in what order the three situations should be placed to make the most reasonable story. The Tomkins-Horn Picture Arrangement Test was changed to The Tomkins-Horn Picture Arrangement Experiment by the Public Opinion Surveys who believed that samples could be easily obtained when the term ‘experiment’ is used instead of ‘test’. The interpretation of the test was not fixed, Silvan Tomkins and Daniel Horn stated that there are always alternate possible interpretations for any rare response in terms of content and in respect to the psychological level involved. The PAT was not developed to differentiate the different levels of psychological levels with respect to all content areas.


Lauren Brincat

Lauren Brincat (born 1980) is an Australian contemporary artist.
She works with multiple mediums including sculpture installations, moving image, and performance. Collaboration with other artists and cross disciplinary practice is a notable feature of her artistic approach. Her installations often encourage audience interaction.
Brincat's works are held in the multiple institutions including the Art Gallery of NSW, Museum of Contemporary Art Australia, and the Art Gallery of Western Australia. Brincat's work "Salt lines: play it as it sounds" was installed at the Carriageworks Arts Centre as part of the 2016 Sydney Bienalle. In 2019 she was co-commissioned by the MCA and Landcom as part of the C3West program to create a living sculpture work titled "The Plant Library".
Brincat graduated from Sydney College of the Arts in 2006 with a Masters of Visual Arts.
Notable works.
Solo works.
Hear This, Museum of Contemporary Art, Australia, 2011.
Shine on you crazy diamond, Museum of Old and New Art, Festival of Modern Art, Hobart, 2010 & Next Wave Federation Square Festival, Melbourne, 2010.
Salt Lines: play it as it sounds, Sydney Biennale. Purchased by the Art Gallery of New South Wales, 2015–16.
Walk the Line (companion piece to Salt Lines), Art Gallery of NSW, 2016.
The Plant Library, Museum of Contemporary Art Sydney, 2019.
Collaborative works and group shows.
Embodied Acts: Live and Alive (part of) Contemporary Australia: Women, Queensland Art Gallery and Gallery of Modern Art, Brisbane, 2012.
The Space Between Us: Anne Landa Award, Art Gallery of NSW, 2013
Sonic Social, Museum of Contemporary Art Australia, 2014.
Other Tempo: Liveworks, Carriageworks, 2019.


ISO/TC 46

ISO/TC 46 is Technical Committee 46 of the International Organization for Standardization (ISO), responsible for Information and documentation.
Overview.
The scope of the committee is 'standardization of practices relating to libraries, documentation and information centres, publishing, archives, records management, museum documentation, indexing and abstracting services, and information science'.
Leadership.
The Technical Committee Chair for term 2018-2022 is Gaëlle Béquet, from France, who is currently in her second term as chairperson (the first was 2014-2017).
Françoise Pellé, also french, served as Chair of the ISO/TC 46 from 2008 to 2014.
Subcommittees.
Most work of the Technical Committee is done by Subcommittees (SC) dealing with a particular field. The Subcommittees are:
ISO/TC 46/SC 9.
ISO/TC 46/SC 9 is the ninth Subcommittee of ISO Technical Committee 46, and is responsible for identification and description of information resources.
As of April 2008, the TC 46/SC 9 was transferred to the American National Standards Institute (ANSI) in the United States.


Cap torque tester

The cap torque tester is used in the packaging industry to measure the opening or closuring torque of the screwing cap. It is a piece of specific quality control equipment that can be placed on the production line or in the laboratory.
Packaging development.
A torque tester is required during the packaging design process. It can be used as a destructive tester to identify if there is any material weakness of the packaging during the screwing process. It also allows one to define the torque tolerances of the capping machine. The lower torque limit is considered the minimum pressure of the cap to avoid any leak of the product. This torque test needs to be combined with a leak test with secure seal analyzer. The higher torque limit is the maximum torque the customer can apply to open or close the product's cap.
Production line control.
Once torque tolerances have been defined, the cap torque tester is used as a torque control device on the final product. If measurements are out of the limits, the capping machine needs to be adjusted. Depending on the production process, it could be necessary to control the opening torque, 24 hours after the packaging process. Temperature variations can modify product characteristics with a result of different torque measurement.


Kernel smoother

A kernel smoother is a statistical technique to estimate a real valued function formula_1 as the weighted average of neighboring observed data. The weight is defined by the kernel, such that closer points are given higher weights. The estimated function is smooth, and the level of smoothness is set by a single parameter.
This technique is most appropriate when the dimension of the predictor is low ("p" < 3), for example for data visualization.
Definitions.
Let formula_2 be a kernel defined by
where:
Popular kernels used for smoothing include parabolic (Epanechnikov), Tricube, and Gaussian kernels.
Let formula_7 be a continuous function of "X". For each formula_8, the Nadaraya-Watson kernel-weighted average (smooth "Y"("X") estimation) is defined by
where:
In the following sections, we describe some particular cases of kernel smoothers.
Gaussian kernel smoother.
The Gaussian kernel is one of the most widely used kernels, and is expressed with the equation below.
Here, b is the length scale for the input space.
Nearest neighbor smoother.
The idea of the nearest neighbor smoother is the following. For each point "X"0, take m nearest neighbors and estimate the value of "Y"("X"0) by averaging the values of these neighbors.
Formally, formula_11, where formula_12 is the "m"th closest to "X"0 neighbor, and
Example:
In this example, "X" is one-dimensional. For each X0, the formula_14 is an average value of 16 closest to "X"0 points (denoted by red). The result is not smooth enough.
Kernel average smoother.
The idea of the kernel average smoother is the following. For each data point "X"0, choose a constant distance size "λ" (kernel radius, or window width for "p" = 1 dimension), and compute a weighted average for all data points that are closer than formula_15 to "X"0 (the closer to "X"0 points get higher weights).
Formally, formula_16 and "D"("t") is one of the popular kernels.
Example:
For each "X"0 the window width is constant, and the weight of each point in the window is schematically denoted by the yellow figure in the graph. It can be seen that the estimation is smooth, but the boundary points are biased. The reason for that is the non-equal number of points (from the right and from the left to the "X"0) in the window, when the "X"0 is close enough to the boundary.
Local linear regression.
In the two previous sections we assumed that the underlying Y(X) function is locally constant, therefore we were able to use the weighted average for the estimation. The idea of local linear regression is to fit locally a straight line (or a hyperplane for higher dimensions), and not the constant (horizontal line). After fitting the line, the estimation formula_17 is provided by the value of this line at "X"0 point. By repeating this procedure for each "X"0, one can get the estimation function formula_18.
Like in previous section, the window width is constant formula_19
Formally, the local linear regression is computed by solving a weighted least square problem.
For one dimension ("p" = 1):
formula_20
The closed form solution is given by:
where:
Example:
The resulting function is smooth, and the problem with the biased boundary points is reduced.
Local linear regression can be applied to any-dimensional space, though the question of what is a local neighborhood becomes more complicated. It is common to use k nearest training points to a test point to fit the local linear regression. This can lead to high variance of the fitted function. To bound the variance, the set of training points should contain the test point in their convex hull (see Gupta et al. reference).
Local polynomial regression.
Instead of fitting locally linear functions, one can fit polynomial functions.
For p=1, one should minimize:
formula_25
with formula_26
In general case (p>1), one should minimize:
formula_27


Management Aptitude Test

Management Aptitude Test (MAT) is a standard aptitude test conducted in India since 1998 by the All India Management Association (AIMA). MAT is used for admission to Master of Business Administration (MBA) and allied programmes by over 600 business schools across India. It was approved by the Ministry of Human Resource Development in 2003.
Format.
Candidates can choose to take either a paper-based or a computer-based test. It is conducted in either English or Hindi. Eligibility is for graduates in any discipline, though final year students of graduate courses can also apply. The test is offered four times in a year in February, May, September and December. The cost of admission was in 2017 and the test scores are valid for one year.
The tests includes 200 questions, 40 in each subject: language comprehension, mathematical skills, data analysis and sufficiency, intelligence and critical reasoning, and Indian and global environment. Time allotted is 150 minutes.


MMCache

MMCache, also known as Turck MMCache, is a PHP accelerator, or an extension to PHP meant to improve performance. It is structured as a simple proxy server between the web server and the web browser. Its most important feature is using memcached for caching the data in memory. MMCache is free software released under the GNU GPL 2.0. The key identifying the given site is designated from the URL, so if, for example, there is a session defined within the URL, then the proxy will not work effectively.
A newer version of MMCache, MMCache-LB, has an option to connect more web servers behind the proxy, with load balancing between them.
Development work on MMCache was discontinued in 2009, and the code was forked into the eAccelerator application.


NBench

NBench, short for Native mode Benchmark and later known as BYTEmark, is a synthetic computing benchmark program developed in the mid-1990s by the now defunct BYTE magazine intended to measure a computer's CPU, FPU, and Memory System speed.
History.
NBench is essentially release 2 of BYTE Magazine's BYTEmark benchmark program (previously known as BYTE's Native Mode Benchmarks), published about 1995, which was just a few years before the magazine ceased publication. NBench is written in C, and was initially focused on PCs running the Microsoft Windows operating system. Independently of BYTE, in 1996 NBench was ported to Linux and other flavors of Unix by Uwe F. Mayer.
More recently Ludovic Drolez prepared an NBench App for the Android mobile device operating system.
NBench should not be confused with the similarly named but unrelated AMD N-Bench.
Design.
The NBench algorithm suite consists of ten different tasks:
A run of the benchmark suite consists essentially of two phases for each of the tests. First, a calibration loop is run to determine the size of the problem the system can handle in a reasonable time, in order to adapt to the ever-faster computer hardware available. Second, the actual test is run repeatedly several times to obtain a statistically meaningful result.
Originally, NBench and BYTEmark produced two overall index figures: Integer index and Floating-point index. The Integer index is the geometric mean of those tests that involve only integer processing—numeric sort, string sort, bitfield, emulated floating-point, assignment, Huffman, and IDEA—while the Floating-point index is the geometric mean of those tests that require the floating-point coprocessor—Fourier, neural net, and LU decomposition. The index figures where relative scores to get a general feel for the performance of the machine under test as compared to a baseline system based on a 90 MHz Pentium Intel CPU.
The Linux/Unix port has a second baseline machine, it is an AMD K6/233 with 32 MB RAM and 512 KB L2-cache running Linux 2.0.32 and using GNU gcc version 2.7.2.3 and libc-5.4.38. The original integer index was split into an integer-operation and a memory-operation index, as suggested by Andrew D. Balsa, reflecting the realization that memory management is important in CPU design. The original tests have been left alone, however, the geometric mean of the tests numeric sort, floating-point emulation, IDEA, and Huffman now constitutes the integer-arithmetic focused benchmark index, while the geometric mean of the tests string sort, bitfield, and assignment makes up the new memory index. The floating point index has been left alone, it is still the geometric mean of fourier, neural net, and LU decomposition.
Use.
The benchmark suite has seen consistent use since the mid-1990s by the personal computing community, on PCs and other devices running various flavors of UNIX including Linux or BSD, or running Windows (usually in combination with Cygwin), and on also on Macs (it is in particular available as a Darwin port).
A results page from runs on many different hardware configurations, from high-powered multi-CPU servers down to low-powered network switches, is maintained by the original porter.
Shortcomings.
Using NBench as a benchmark has pitfalls:


5379 Abehiroshi


Mosaic plot

A mosaic plot (also known as a Marimekko diagram) is a graphical method for visualizing data from two or more qualitative variables. It is the multidimensional extension of spineplots, which graphically display the same information for only one variable. It gives an overview of the data and makes it possible to recognize relationships between different variables. For example, independence is shown when the boxes across categories all have the same areas. Mosaic plots were introduced by Hartigan and Kleiner in 1981 and expanded on by Friendly in 1994. Mosaic plots are also called Mekko charts due to their resemblance to a Marimekko print.
As with bar charts and spineplots, the area of the tiles, also known as the bin size, is proportional to the number of observations within that category.
Example.
A classic example of mosaic plots uses data from the passengers on the "Titanic". The data used for this example has 2201 observations and 3 variables. The variables are:
The observations were compiled into the following table:
Mosaic plot construction.
The categorical variables are first put in order. Then, each variable is assigned to an axis. In the table to the right, sequence and classification is presented for this data set. Another ordering will result in a different mosaic plot, i.e., the order of the variables is significant as for all multivariate plots.
At the left edge of the first variable we first plot "Gender," meaning that we divide the data vertically in two blocks: the bottom blocks corresponds to females, while the upper (much larger) one to males. One immediately sees that roughly a quarter of the passengers were female and the remaining three quarters male.
One then applies the second variable "Class" to the top edge. The four vertical columns therefore mark the four values of that variable (1st, 2nd, 3rd, and crew). These columns are of variable thickness, because column width indicates the relative proportion of the corresponding value on the population. Crew plainly represents the largest male group, whereas third-class passengers are the largest female group. The number of female crew members is also seen to have been marginal.
The last variable ("Survived") is finally applied, this time along the left edge with the result highlighted by shade: dark grey rectangles represent people that did not survive the disaster, light grey ones people that did. Women in the first class are immediately seen to have had the highest survival probability. The survival probability for females is seen to have been higher than that for men (marginalised over all classes). Similarly, a marginalization over gender identifies first-class passengers as most probable to survive. Overall, about 1/3 of all people survived (proportion of light gray areas).


Arcfourth


Tank EX

Tank Ex, or MBT Ex, was the code name of the main battle tank developed by the Indian Defence Research and Development Organisation (DRDO) in 2002. It was rumoured the tank would be called "Karna", after one of the heroes of the Indian epic "The Mahabharata". Tank Ex was developed as a second attempt after the development of the Ajeya (an upgraded T-72) by DRDO in order to capitalize on the technology developed for that project. It underwent six months of trials, but was subsequently rejected by the Indian Army. Total eight Tank Ex prototypes were built.
History.
The Tank Ex MBT uses the chassis of the T-72M1 (Ajeya) and turret and weapon system of the Arjun. It was developed in 2002 as a private venture and was intended to provide a solution for upgrading the Indian Army's ageing T-72M1 fleet. It was rejected by the Indian Army after eight prototypes and six months of trials.
On July 5, 2008, Gen. Dalip Bhardwaj, the Indian Army's Director General of Mechanized forces (DGMF), declared that the army had rejected Tank Ex. This was part of an announcement that there would be no further orders for Arjun tanks, and that the military would be inviting participants from various countries to discuss future tank developments.
Specifications.
Weighing in at 47 tons, the Tank Ex is heavier than the T-72M1 (41 tons) and much lighter than the Arjun MBT, (58.4 tons). It has a power plant giving a power-to-weight ratio of /ton for a total weight of 47 tons. This represents an improvement over the T-72M1's /ton, with a weight of 41 tons and a power plant. The Tank Ex utilizes the Arjun MBT's 120 mm rifled gun firing unitary APFSDS and HESH semi combustible cartridge case ammunition. A total of 32 rounds are carried, as compared with 39 in the Arjun and 45 two piece rounds in the T-72. A global positioning system is provided for accurate navigation. This is a feature common to both the Arjun MBT and the Combat Improved "Ajeya".
The Tank Ex utilizes the "Kanchan" composite armour, especially over its frontal arc (turret as well as glacis), giving it protection against both Kinetic and HEAT rounds. The usage of the "Arjun" turret design indicates that the Tank Ex may also have its "ready" ammunition stored in the bustle (as in the Arjun), separated from the crew and provided with blow-off panels. This would be a significant protective feature comparable with Western design practices. The Tank Ex retains the T-72's mobility, with a road speed of 60 km/h and a cross-country speed of 40 km/h. With a maximum gradient climb of 30 degrees, it remains in line with all variants of the T-72, like the T-72BM. The Tank Ex is better at trench crossing with a capability of crossing 2.6 meters as compared to the T-72M1's 2.28 metres. The Tank Ex can also climb vertical obstacles up to 0.85 metres tall. The tank's shallow fording capabilities are quoted as 1.2 metres. The Tank Ex should also have the capability to fire the Israeli LAHAT missile from its gun-barrel, like the "Arjun".


886 Washingtonia

886 Washingtonia is a minor planet orbiting the Sun. It was discovered on 16 November 1917, from Washington, D.C. and is named after the 1st President of the United States, George Washington.
Discovery circumstances.
Credit for the discovery of 886 Washingtonia has been given to George Peters of the US Naval Observatory, who was the first to report it. The object was, however, observed four days earlier by Margaret Harwood, who was advised not to report it as a new discovery because "it was inappropriate that a woman should be thrust into the limelight with such a claim". The first woman to be credited with the discovery of a minor planet was Pelageya Fedorovna Shajn, eleven years later.


Japanese mode

The organization of notes to create a musical scale has many different applications in different cultures and types of music. One of the most common approaches to organizing musical structures is known as the Mode or Mode(s). Since the Heian Period, there has been disagreement and contention between musical scholars regarding Japanese music and modal theory. There has long been a debate about Japanese modes and what defines them, to this day there is not a single modal theory that can completely explain Japanese music. Music Scales are critical in clarifying and identifying musical pieces, however, there has been no single scale model that can identify all Japanese music into one classification or category of music. In order to be understood by western scholars, The different variations of Japanese modal scales are often compared to the western Major Scale. Various modal theories from around the world have been imported to attempt and analyze Japanese music structure, but often the modal theories suggested do not reflect what is actually present in the music it is being applied to. The classical structures of Most Japanese music originates in China and was not concerned with developing a universal scale or mode until Western music had been imported. After the Heian period began was when Western modal theories became widely acknowledged by Japanese society, though it often stayed in its own category as it could not entirely explain Japanese music across all its different iterations.
The most common version of the Japanese mode is a somewhat inaccurate term for a pentatonic musical scale which is used commonly in traditional Japanese music. The intervals of the scale are major second, minor third, major fifth, and minor sixth (for example, the notes A, B, C, E, F and up to A. cf. .) - which is essentially a natural minor scale in Western music theory without the subdominant and subtonic, which is the same operation performed on the major scale to produce the pentatonic major scale. The more correct term would be "kumoijoshi", as given by William P. Malm for one of the three tuning scales of the koto adapted from shamisen music.
In addition to being used almost exclusively in traditional Japanese compositions, it is found frequently in video game music and the pieces of contemporary composers such as Anne Boyd.
History.
Evidence of music in Japan before the 6th century is present, but very limited and knowledge surrounding its theory is even understood. It is not until the Nara period do we see a more consistent form of art music beginning to flourish in Japan. During the Nara period, Gagaku court music was introduced from China and then modified to fit Japanese styles and taste. Similar to Buddhism and Confucianism, music and musical instruments were introduced to Japan from China in the 12th Century. These musical theories, instruments, and styles imported came to shape much of traditional Japanese Music known today. Though much of Chinese music and music theory was re purposed for distinct Japanese styles, it still held on to many of the core elements of Chinese traditional music of the time. The standard theory imported from China consisted of an octave scale with twelve pitches derived from the circle of fifths During the Edo Period, Japan was shut off from the rest of the world, many different new musical styles arose from this isolation and shaped modern Japanese Music. It is theorized that this is one of the reasons that music theorists today have had such difficult time developing a single theoretical solution to all of Japanese music.
Different Types of Japanese Scales and Modes.
Gagaku Scale: Introduced from China during the Nara Period, but then later modified during the Heian Period. The Gagaku Scale is a heptatonic scale, created from 12 chromatic tones and assembled by fifths.
In and Yo Scales: Uehara Rokushiro coined these two scales in the late 1800s. They were among the first scales developed as a scholarly approach to Japanese music. Both scales use a H W H W H pattern, but the Yo scales differs due to the fact that 3 of its degrees are sharped.
Minyo and Ritsu Scales: There are various different arrangements of notes that different historians would consider these scales, however they are usually classified as being 5 note scales without any semitones. The most widely intervalic theory behind them is classified by a Major second, Minor Third, major second, and a minor third.


Singaporean units of measurement

Several units of measurement were historically used in Singapore to measure length, mass, and volume. During 1968–1970, the metric system was adopted in Singapore. The metric system is used for most official purposes and only metric measures are permitted for trade. Despite these restrictions, fabric is still commonly sold by the square yard. Area is still expressed in square feet and less frequently acres, and bodily height is also commonly expressed in feet and inches.
System during the later half of the 19th century.
Several units were used in Singapore under Straits Settlements.


List of longest road tunnels

This page presents a list of the longest road tunnels of the world. This page lists all road tunnels longer than .


Polarization spectroscopy

Polarization spectroscopy comprises a set of spectroscopic techniques based on polarization properties of light (not necessarily visible one; UV, X-ray, infrared, or in any other frequency range of the electromagnetic radiation). By analyzing the polarization properties of light, decisions can be made about the media that emitted the light (or the media the light passes/scatters through). Alternatively, a source of polarized light may be used to probe a media; in this case, the changes in the light polarization (comparing to the incidental one) allow to infer the media properties.
In general, any kind of anisotropy in the media results in some sort of change in polarization. Such an anisotropy can be either inherent to the media (e.g., in the case of a crystal substance), or imposed externally (e.g., in the presence of magnetic field in plasma).


Boston Evening Transcript

The Boston Evening Transcript was a daily afternoon newspaper in Boston, Massachusetts, published from July 24, 1830, to April 30, 1941.
Beginnings.
"The Transcript" was founded in 1830 by Henry Dutton and James Wentworth of the firm of Dutton and Wentworth, who were, at that time, the official state printers of Massachusetts. and Lynde Walter who was also the first editor of the "Transcript". Dutton and Wentworth agreed to this as long as Walter would pay the expenses of the initial editions of the newspaper.
In 1830 "The Boston Evening Bulletin", which had been a penny paper, ceased publication. Lynde Walter decided to use the opening provided to start a new evening penny paper in Boston. Walter approached Dutton and Wentworth with the proposal that he would edit the paper and that they would do the printing and circulation.
"The Transcript" first appeared on July 24, 1830, however after three days Walter suspended publication of the paper until he could build up his patronage. After Walter canvassed the city to better develop the paper's business "The Transcript" resumed publication on August 28, 1830.
After Lynde Walter died, his sister, Cornelia Wells Walter, who had been the "Transcript" 's theatre critic, became, at 29, the editor of the "Transcript", becoming the first woman to become the editor of a major American daily. Cornelia Walter served as the editor of "The Transcript" from 1842 to 1847.
Great Fire.
The "Transcript" 's offices were destroyed in the Great Boston Fire of 1872. After the Great Fire "The Transcript" 's offices on Washington Street were rebuilt and expanded.
Literary influence.
In 1847 the poet Epes Sargent became editor of the paper. Many literary and poetic works debuted in the "Transcript's" pages.
An early version of "America the Beautiful" by Katharine Lee Bates first appeared in "The Boston Evening Transcript" on November 19, 1904.
Hazel Hall (poet)'s first published poem "To an English Sparrow", first appeared in "The Transcript" in 1916.
Features and columns.
Features and columns included: "Suburban Scenes", "The Listener", "The Nomad", "The Librarian", "Saturday Night Thoughts", as well as extensive book reviews and music criticism. "The Transcript" also had a Washington bureau, a college sports pages and a department of Bridge. In addition "The Transcript" had a well known genealogy column.
Harvard Medical School's first U.S. animal vivisection lab raised concern from then editor-in-chief Edward Clement, and the paper subsequently ran a series of anti-vivisection editorials.
In the summer of 1940 when Britain faced invasion in World War II, children were being evacuated overseas under a British Government scheme known as the Children's Overseas Reception Board. The readers of the "Boston Evening Transcript" readily responded and agreed to sponsor a group of children. A group of 48 children left England on RMS Scythia (Cunard Line) 19,730 tons, from Liverpool on 24 September 1940 bound for Boston.
Genealogical columns.
Because of the genealogy column "The Transcript" is of value to historians and others. Gary Boyd Roberts of the New England Historic Genealogical Society noted:
The "Boston Evening Transcript", like the "New York Times" today, was a newspaper of record. Its genealogical column, which usually ran twice or more a week for several decades in the early twentieth century, was often an exchange among the most devoted and scholarly genealogists of the day. Many materials not published elsewhere are published therein.
In popular literature.
"The Boston Evening Transcript" is also the title of a poem by T. S. Eliot which reads:


Sphygmograph

The sphygmograph ( ) was a mechanical device used to measure blood pressure in the mid-19th century. It was developed in 1854 by German physiologist Karl von Vierordt (1818–1884). It is considered the first external, non-intrusive device used to estimate blood pressure.
The device was a system of levers hooked to a scale-pan in which weights were placed to determine the amount of external pressure needed to stop blood flow in the radial artery. Although the instrument was cumbersome and its measurements imprecise, the basic concept of Vierordt's sphygmograph eventually led to the blood pressure cuff used today.
In 1863, Étienne-Jules Marey (1830–1904) improved the device by making it portable. Also he included a specialized instrument to be placed above the radial artery that was able to magnify pulse waves and record them on paper with an attached pen.
In 1880, Samuel von Basch (1837–1905) invented the sphygmomanometer, which was then improved by Scipione Riva-Rocci (1863–1937) in the 1890s. In 1901 Harvey Williams Cushing improved it further, and Heinrich von Recklinghausen (1867–1942) used a wider cuff, and so it became the first accurate and practical instrument for measuring blood pressure.


Orders of magnitude (numbers)

This list contains selected positive numbers in increasing order, including counts of things, dimensionless quantity and probabilities. Each number is given a name in the short scale, which is used in English-speaking countries, as well as a name in the long scale, which is used in some of the countries that do not have English as their national language.
10−24.
ISO: yocto- (y)
10−21.
ISO: zepto- (z)
10−18.
ISO: atto- (a)
10−15.
ISO: femto- (f)
10−12.
ISO: pico- (p)
10−9.
ISO: nano- (n)
10−6.
ISO: micro- (μ)
10−3.
ISO: milli- (m)
10−2.
ISO: centi- (c)
10−1.
ISO: deci- (d)
101.
ISO: deca- (da)
102.
ISO: hecto- (h)
103.
ISO: kilo- (k)
105.
(; one hundred thousand or a lakh).
106.
ISO: mega- (M)
109.
ISO: giga- (G)
1012.
ISO: tera- (T)
1015.
ISO: peta- (P)
1018.
ISO: exa- (E)
1021.
ISO: zetta- (Z)
1024.
ISO: yotta- (Y)


Laser-induced incandescence

Laser-induced incandescence (LII) is a non-intrusive method of measuring time-resolved soot particle volume fraction and primary particle sizes in flames.


Subduction polarity reversal

Subduction polarity reversal is a geologic process in which two converging plates switch roles: The over-lying plate becomes the down-going plate, and vice versa. There are two basic units which make up a subduction zone. This consists of an overriding plate and the subduction plate. Two plates move towards each other due to tectonic forces. The overriding plate will be on the top of the subducting plate. This type of tectonic interaction is found at many plate boundaries.
However, some geologists propose that the roles of the overriding plate and subducting plate do not remain the same indefinitely. Their roles will swap, which means the plate originally subducting beneath will become the overriding plate. This phenomenon is called subduction switch, the flipping of subduction polarity or subduction polarity reversal.
Examples of subduction systems with subduction polarity reversal are:
Background.
The phenomenon of subduction polarity reversal has been identified in the collision of an intra-oceanic subduction system, which is the collision of two oceanic plates. When two oceanic plates migrate towards each other, one subducts below the other. Generally, the oceanic plate with higher density subducts beneath and the other one overrides the down-going slab. The process continues until a buoyant continental margin sitting on the top of the subducting plate is introduced into the down-going slab. The subduction of the slab becomes slower and may even cease. Geologists propose various possible models to predict what will be the next step for the intra-oceanic subduction system with the involvement of buoyant continental crust. One of the possible results is subduction polarity reversal.
Models of subduction polarity reversal.
Even though many geologists agree that after the involvement of buoyant continental crust, subduction polarity reversal may occur, they have different opinions towards the mechanisms leading to the change of subduction direction. Thus, there is no single model to represent subduction polarity reversal. How geologists develop the models depends on the parameters they focus on. Some geologists attempt to construct models of subduction reversal through laboratory experiments or observations. There are three common models: slab break-off, double convergence and lithospheric break-up.
The models of slab-break up and double convergence are based on observations by geologists, and the lithosphere break-up model is based on experimental simulation.
The criteria for having subduction polarity reversal are
Different models representing the subduction polarity reversal depends highly on parameters the Geologists considered. Here is the summary table showing the comparison models.
Slab break-off.
This model was developed by analyzing the geological cross section along the collision between Eurasian plate and the Philippine sea plate, which is the location of an ongoing flipping of subduction polarity.
When two oceanic plates migrate towards each other, one plate overrides another forming a subduction system. Later, a light and buoyant passive continental margin introduced into this system will cause the cessation of subduction system. On one hand, the buoyant plate resists subduction beneath the overriding plate. On the other hand, the dense oceanic slab at the subducting plate prefers to move downward. These opposite forces will generate a tensile force or gravitational instability on the downward slab and lead to the break-off of the slab. The space where the break-off slab separates will form a mantle window. Subsequently, the less dense continental margin forms the overriding plate, while the oceanic plate becomes the subducting slab. The direction of the subduction system changes since the break-off of slab creates the space, which is the major parameter of this model.
Double convergence model.
This model is developed based on the geological evolution of Alpine and Apennine subduction.
Similarly, two oceanic plates move towards each other. The subduction process ceases with the involvement of buoyant continental block. A new slab is formed at the overriding plate owing to the regional compression and the difference in density between the continental block and oceanic plate. An orogenic wedge is built. However, there is an obvious space problem about how to accommodate two slabs. The solution is the new developing slab moves not only vertically, but also laterally leading to a deep strike-slip movement. The development of co-existence of two opposite slabs is described as a double sided subduction or doubly convergent wedge. Eventually, the development of new slab grows and slides onto the old slab. The old slab breaks off and the orogenic wedge collapses. The new slab stops the lateral motion and subducts beneath. The direction of subduction system changes.
Lithosphere break-up.
The lithosphere break-up model is simulated by hydrocarbon experiments in the laboratory. The researchers set up the setting of subduction zone which are analogized by hydrocarbons with different densities representing various layers in the subduction zone.
The initial setting of the simulated subduction zone model is confined by two pistons. The piston connected to the overriding plate is locked, while the piston linking to subducting plate is subjected to a constant rate of compression. More importantly, there is a relatively thin magmatic arc and pre-existing fault dipping towards the subducting plate at the overriding plate. The detachment of the pre-existing fault occurs when buoyant continental margin is in contact with the overriding plate. It is because the buoyant margin resists subduction and significantly increases the frictional force in the contact region. The subduction then stops. Subsequently, the new subducting slab develops at an overriding plate with the continuous compression. The new developing slab eventually penetrates and breaks the old slab. A new subduction zone is formed with an opposite polarity to the previous one.
In reality, the magmatic arc is a relatively weak zone at the overriding plate because it has a thin lithosphere and is further weakened by high heat flow and hot fluid. Pre-existing faults in this simulation are also common in the magmatic arc. This experiment is a successful analogy to subduction polarity reversal happening at Kamchatka in early Eocene and the active example at Taiwan region as well as at Timor.
Taiwan as an active example of flipping of subduction reversal.
A sharp contrast of landforms in Taiwan lures many people to investigate. The northern part of Taiwan has many flat plains such as Ilan Plain and Pingtung Plain, while the southern part of Taiwan is concentrated with many high mountains like Yushan reaching about 3950m. This huge difference in topography is the consequence of the flipping of subduction polarity. Most of models studying this phenomenon will focus on an active collision in Taiwan which appears to reveal the incipient stages of subduction reversal.
The collision of N- trending Luzon arc in Philippine Sea plate (PP) with E-trending Eurasian plate (EP) started at mid-Miocene forming an intra-oceanic subduction system. Taiwan was formed by this process. The south-north topographic difference in Taiwan is like a story book telling the evolution in subduction zone. The Philippine Sea plate subducts below the Eurasian plate at south-west part of WEP (Western edge of north-dipping Philippine Sea Plate), and the latter overrides the former at north east part of WEP. The collision between two plates started at the Northern Taiwan and propagated south with the younger region at the southern part. Each incipient stage of subduction reversal process could be studied by correlating cross-sections in various parts of Taiwan.


Fiber-optic sensor

A fiber-optic sensor is a sensor that uses optical fiber either as the sensing element ("intrinsic sensors"), or as a means of relaying signals from a remote sensor to the electronics that process the signals ("extrinsic sensors"). Fibers have many uses in remote sensing. Depending on the application, fiber may be used because of its small size, or because no electrical power is needed at the remote location, or because many sensors can be multiplexed along the length of a fiber by using light wavelength shift for each sensor, or by sensing the time delay as light passes along the fiber through each sensor. Time delay can be determined using a device such as an optical time-domain reflectometer and wavelength shift can be calculated using an instrument implementing optical frequency domain reflectometry.
Fiber-optic sensors are also immune to electromagnetic interference, and do not conduct electricity so they can be used in places where there is high voltage electricity or flammable material such as jet fuel. Fiber-optic sensors can be designed to withstand high temperatures as well.
Intrinsic sensors.
Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the quantity to be measured modulates the intensity, phase, polarization, wavelength or transit time of light in the fiber. Sensors that vary the intensity of light are the simplest, since only a simple source and detector are required. A particularly useful feature of intrinsic fiber-optic sensors is that they can, if required, provide distributed sensing over very large distances.
Temperature can be measured by using a fiber that has evanescent loss that varies with temperature, or by analyzing the Rayleigh Scattering, Raman scattering or the Brillouin scattering in the optical fiber. Electrical voltage can be sensed by nonlinear optical effects in specially-doped fiber, which alter the polarization of light as a function of voltage or electric field. Angle measurement sensors can be based on the Sagnac effect.
Special fibers like long-period fiber grating (LPG) optical fibers can be used for direction recognition
. Photonics Research Group of Aston University in UK has some publications on vectorial bend sensor applications.
Optical fibers are used as hydrophones for seismic and sonar applications. Hydrophone systems with more than one hundred sensors per fiber cable have been developed. Hydrophone sensor systems are used by the oil industry as well as a few countries' navies. Both bottom-mounted hydrophone arrays and towed streamer systems are in use. The German company Sennheiser developed a laser microphone for use with optical fibers.
A fiber-optic microphone and fiber-optic based headphone are useful in areas with strong electrical or magnetic fields, such as communication amongst the team of people working on a patient inside a magnetic resonance imaging (MRI) machine during MRI-guided surgery.
Optical fiber sensors for temperature and pressure have been developed for downhole measurement in oil wells. The fiber-optic sensor is well suited for this environment as it functions at temperatures too high for semiconductor sensors (distributed temperature sensing).
Optical fibers can be made into interferometric sensors such as fiber-optic gyroscopes, which are used in the Boeing 767 and in some car models (for navigation purposes). They are also used to make hydrogen sensors.
Fiber-optic sensors have been developed to measure co-located temperature and strain simultaneously with very high accuracy using fiber Bragg gratings. This is particularly useful when acquiring information from small or complex structures. Fiber optic sensors are also particularly well suited for remote monitoring, and they can be interrogated 290 km away from the monitoring station using an optical fiber cable. Brillouin scattering effects can also be used to detect strain and temperature over large distances (20–120 kilometers).
Other examples.
A fiber-optic AC/DC voltage sensor in the middle and high voltage range (100–2000 V) can be created by inducing measurable amounts of Kerr nonlinearity in single mode optical fiber by exposing a calculated length of fiber to the external electric field. The measurement technique is based on polarimetric detection and high accuracy is achieved in a hostile industrial environment.
High frequency (5 MHz–1 GHz) electromagnetic fields can be detected by induced nonlinear effects in fiber with a suitable structure. The fiber used is designed such that the Faraday and Kerr effects cause considerable phase change in the presence of the external field. With appropriate sensor design, this type of fiber can be used to measure different electrical and magnetic quantities and different internal parameters of fiber material.
Electrical power can be measured in a fiber by using a structured bulk fiber ampere sensor coupled with proper signal processing in a polarimetric detection scheme. Experiments have been carried out in support of the technique.
Fiber-optic sensors are used in electrical switchgear to transmit light from an electrical arc flash to a digital protective relay to enable fast tripping of a breaker to reduce the energy in the arc blast.
Fiber Bragg grating based fiber-optic sensors significantly enhance performance, efficiency and safety in several industries. With FBG integrated technology, sensors can provide detailed analysis and comprehensive reports on insights with very high resolution. These type of sensors are used extensively in several industries like telecommunication, automotive, aerospace, energy, etc. Fiber Bragg gratings are sensitive to the static pressure, mechanical tension and compression and fiber temperature changes. The efficiency of fiber Bragg grating based fiber-optic sensors can be provided by means of central wavelength adjustment of light emitting source in accordance with the current Bragg gratings reflection spectra.
Extrinsic sensors.
Extrinsic fiber-optic sensors use an optical fiber cable, normally a multimode one, to transmit modulated light from either a non-fiber optical sensor, or an electronic sensor connected to an optical transmitter. A major benefit of extrinsic sensors is their ability to reach places which are otherwise inaccessible. An example is the measurement of temperature inside aircraft jet engines by using a fiber to transmit radiation into a radiation pyrometer located outside the engine. Extrinsic sensors can also be used in the same way to measure the internal temperature of electrical transformers, where the extreme electromagnetic fields present make other measurement techniques impossible.
Extrinsic fiber-optic sensors provide excellent protection of measurement signals against noise corruption. Unfortunately, many conventional sensors produce electrical output which must be converted into an optical signal for use with fiber. For example, in the case of a platinum resistance thermometer, the temperature changes are translated into resistance changes. The PRT must therefore have an electrical power supply. The modulated voltage level at the output of the PRT can then be injected into the optical fiber via the usual type of transmitter. This complicates the measurement process and means that low-voltage power cables must be routed to the transducer.
Extrinsic sensors are used to measure vibration, rotation, displacement, velocity, acceleration, torque, and temperature.
Chemical sensors and biosensors.
It is well-known the propagation of light in optical fiber is confined in the core of the fiber based on the total internal reflection (TIR) principle and near-zero propagation loss within the cladding, which is very important for the optical communication but limits its sensing applications due to the non-interaction of light with surroundings. Therefore, it is essential to exploit novel fiber-optic structures to disturb the light propagation, thereby enabling the interaction of the light with surroundings and constructing fiber-optic sensors. Until now, several methods, including polishing, chemical etching, tapering, bending, as well as femtosecond grating inscription, have been proposed to tailor the light propagation and prompt the interaction of light with sensing materials. In the above-mentioned fiber-optic structures, the enhanced evanescent fields can be efficiently excited to induce the light to expose to and interact with the surrounding medium. However, the fibers themselves can only sense very few kinds of analytes with low-sensitivity and zero-selectivity, which greatly limits their development and applications, especially for biosensors that require both high-sensitivity and high-selectivity.
To overcome the issue, an efficient way is to resort to responsive materials, which possess the ability to change their properties, such as RI, absorption, conductivity, etc., once the surrounding environments change. Due to the rapid progress of functional materials in recent years, various sensing materials are available for fiber-optic chemical sensors and biosensors fabrication, including graphene, metals and metal oxides, carbon nanotubes, nanowires, nanoparticles, polymers, quantum dots, etc. Generally, these materials reversibly change their shape/volume upon stimulation by the surrounding environments (the target analysts), which then leads to the variation of RI or absorption of the sensing materials. Consequently, the surrounding changes will be recorded and interrogated by the optical fibers, realizing sensing functions of optical fibers. Currently, various fiber-optic chemical sensors and biosensors have been proposed and demonstrated.


Permutation test


Concerto for Horn and Hardart

The Concerto for Horn and Hardart is a work of Peter Schickele composing under the pseudonym P. D. Q. Bach. The work is a parody of the classical double concerto but where one instrument, the hardart, uses different devices, such as plucked strings, blown whistles and popped balloons, to produce each note in its range. The name "hardart" and the name of the concerto is a play on the name of proprietors Horn & Hardart, who pioneered the North American use of the automat. Like the automat, the hardart had small windows in the front where the musician had to insert coins to remove implements needed to strike or otherwise play the devices that produced the notes. The composer Philip Glass, a classmate of Schickele's, helped build the actual instrument; Glass and the others tasked with building the hardart made it a transposing instrument without telling Schickele. Although a parody, the work is a well-written example of a classical concerto and could stand as a serious piece of music with a few changes.
The piece is in three movements:
The first movement is in sonata form, though with numerous mishaps. It quotes Wolfgang Amadeus Mozart's Symphony No. 29. The second is a set of variations which, as Schickele notes, have no relationship to the initial theme. It quotes Piano Concerto No. 21 (Mozart). It concludes with a cadenza that shows off the abilities of the hardart. The third movement, a minuet ("with cream and sugar"), ends with the bursting of the balloons on the hardart.
A portion of the cadenza was sampled by the group Jurassic 5 in the song "Monkey Bars" on their album "Quality Control".
The inscription "Minor Labor Matris" on the hardart is Latin for "Less Work for Mother", the advertising slogan adopted by Horn & Hardart in 1924.