text
null | inputs
dict | prediction
null | prediction_agent
null | annotation
list | annotation_agent
null | multi_label
bool 1
class | explanation
null | id
stringlengths 1
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stringclasses 2
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{
"abstract": " The linear momentum and angular momentum of virtual photons of quantum vacuum\nfluctuations can induce the Casimir force and the Casimir torque, respectively.\nWhile the Casimir force has been measured extensively, the Casimir torque has\nnot been observed experimentally though it was predicted over forty years ago.\nHere we propose to detect the Casimir torque with an optically levitated\nnanorod near a birefringent plate in vacuum. The axis of the nanorod tends to\nalign with the polarization direction of the linearly polarized optical\ntweezer. When its axis is not parallel or perpendicular to the optical axis of\nthe birefringent crystal, it will experience a Casimir torque that shifts its\norientation slightly. We calculate the Casimir torque and Casimir force acting\non a levitated nanorod near a birefringent crystal. We also investigate the\neffects of thermal noise and photon recoils on the torque and force detection.\nWe prove that a levitated nanorod in vacuum will be capable of detecting the\nCasimir torque under realistic conditions.\n",
"title": "Detecting Casimir torque with an optically levitated nanorod"
}
| null | null | null | null | true | null |
12701
| null |
Default
| null | null |
null |
{
"abstract": " We study the eigenvalues of the semiclassical Witten Laplacian $\\Delta_\\phi$\nassociated to a potential $\\phi$. We consider the case where the sequence of\nArrhenius numbers $S_1\\leq \\ldots\\leq S_n$ associated to $\\phi$ is degenerated,\nthat is the preceding inequality are not necessarily strict.\n",
"title": "About small eigenvalues of Witten Laplacian"
}
| null | null | null | null | true | null |
12702
| null |
Default
| null | null |
null |
{
"abstract": " Delay-coordinate maps have been widely used recently to study nonlinear\ndynamical systems, where there is only access to the time series of one of\ntheir variables. Here, we show how the partial control method can be applied in\nthis kind of framework in order to prevent undesirable situations for the\nsystem or even to reduce the variability of the observable time series\nassociated with it. The main advantage of this control method, is that it\nallows to control delay-coordinate maps even if the control applied is smaller\nthan the external disturbances present in the system. To illustrate how it\nworks, we have applied it to three well-known models in Nonlinear Dynamics with\ndifferent delays such as the two-dimensional cubic map, the standard map and\nthe three-dimensional hyperchaotic Hénon map. For the first time we show here\nhow hyperchaotic systems can be partially controlled.\n",
"title": "Partial control of delay-coordinate maps"
}
| null | null | null | null | true | null |
12703
| null |
Default
| null | null |
null |
{
"abstract": " We developed an automated deep learning system to detect hip fractures from\nfrontal pelvic x-rays, an important and common radiological task. Our system\nwas trained on a decade of clinical x-rays (~53,000 studies) and can be applied\nto clinical data, automatically excluding inappropriate and technically\nunsatisfactory studies. We demonstrate diagnostic performance equivalent to a\nhuman radiologist and an area under the ROC curve of 0.994. Translated to\nclinical practice, such a system has the potential to increase the efficiency\nof diagnosis, reduce the need for expensive additional testing, expand access\nto expert level medical image interpretation, and improve overall patient\noutcomes.\n",
"title": "Detecting hip fractures with radiologist-level performance using deep neural networks"
}
| null | null | null | null | true | null |
12704
| null |
Default
| null | null |
null |
{
"abstract": " Background: In this paper we present the approaches and methods employed in\norder to deal with a large scale multi-label semantic indexing task of\nbiomedical papers. This work was mainly implemented within the context of the\nBioASQ challenge of 2014. Methods: The main contribution of this work is a\nmulti-label ensemble method that incorporates a McNemar statistical\nsignificance test in order to validate the combination of the constituent\nmachine learning algorithms. Some secondary contributions include a study on\nthe temporal aspects of the BioASQ corpus (observations apply also to the\nBioASQ's super-set, the PubMed articles collection) and the proper adaptation\nof the algorithms used to deal with this challenging classification task.\nResults: The ensemble method we developed is compared to other approaches in\nexperimental scenarios with subsets of the BioASQ corpus giving positive\nresults. During the BioASQ 2014 challenge we obtained the first place during\nthe first batch and the third in the two following batches. Our success in the\nBioASQ challenge proved that a fully automated machine-learning approach, which\ndoes not implement any heuristics and rule-based approaches, can be highly\ncompetitive and outperform other approaches in similar challenging contexts.\n",
"title": "Large-Scale Online Semantic Indexing of Biomedical Articles via an Ensemble of Multi-Label Classification Models"
}
| null | null |
[
"Statistics"
] | null | true | null |
12705
| null |
Validated
| null | null |
null |
{
"abstract": " The last decades have seen an unprecedented increase in the availability of\ndata sets that are inherently global and temporally evolving, from remotely\nsensed networks to climate model ensembles. This paper provides a view of\nstatistical modeling techniques for space-time processes, where space is the\nsphere representing our planet. In particular, we make a distintion between (a)\nsecond order-based, and (b) practical approaches to model temporally evolving\nglobal processes. The former are based on the specification of a class of\nspace-time covariance functions, with space being the two-dimensional sphere.\nThe latter are based on explicit description of the dynamics of the space-time\nprocess, i.e., by specifying its evolution as a function of its past history\nwith added spatially dependent noise.\nWe especially focus on approach (a), where the literature has been sparse. We\nprovide new models of space-time covariance functions for random fields defined\non spheres cross time. Practical approaches, (b), are also discussed, with\nspecial emphasis on models built directly on the sphere, without projecting the\nspherical coordinate on the plane.\nWe present a case study focused on the analysis of air pollution from the\n2015 wildfires in Equatorial Asia, an event which was classified as the year's\nworst environmental disaster. The paper finishes with a list of the main\ntheoretical and applied research problems in the area, where we expect the\nstatistical community to engage over the next decade.\n",
"title": "Modeling Temporally Evolving and Spatially Globally Dependent Data"
}
| null | null | null | null | true | null |
12706
| null |
Default
| null | null |
null |
{
"abstract": " This paper presents a new method for 3D action recognition with skeleton\nsequences (i.e., 3D trajectories of human skeleton joints). The proposed method\nfirst transforms each skeleton sequence into three clips each consisting of\nseveral frames for spatial temporal feature learning using deep neural\nnetworks. Each clip is generated from one channel of the cylindrical\ncoordinates of the skeleton sequence. Each frame of the generated clips\nrepresents the temporal information of the entire skeleton sequence, and\nincorporates one particular spatial relationship between the joints. The entire\nclips include multiple frames with different spatial relationships, which\nprovide useful spatial structural information of the human skeleton. We propose\nto use deep convolutional neural networks to learn long-term temporal\ninformation of the skeleton sequence from the frames of the generated clips,\nand then use a Multi-Task Learning Network (MTLN) to jointly process all frames\nof the generated clips in parallel to incorporate spatial structural\ninformation for action recognition. Experimental results clearly show the\neffectiveness of the proposed new representation and feature learning method\nfor 3D action recognition.\n",
"title": "A New Representation of Skeleton Sequences for 3D Action Recognition"
}
| null | null | null | null | true | null |
12707
| null |
Default
| null | null |
null |
{
"abstract": " Given an equivalence relation ~ on a set U, there are two abstract notions of\nan element of the quotient set U/~. The #1 abstract notion is a set S=[u] of\nequivalent elements of U (an equivalence class); the #2 notion is an abstract\nentity u_{S} that is definite on what is common to the elements of the\nequivalence class S but is otherwise indefinite on the differences between\nthose elements. For instance, the #1 interpretation of a homotopy type is an\nequivalence class of homotopic spaces, but the #2 interpretation, e.g., as\ndeveloped in homotopy type theory, is an abstract space (without points) that\nhas the properties that are in common to the spaces in the equivalence class\nbut is otherwise indefinite. In philosophy, the #2 abstract entities might be\ncalled paradigm-universals, e.g., `the white thing' as opposed to the #1\nabstract notion of \"the set of white things\" (out of some given collection U).\nThe paper shows how this #2 notion of a paradigm may be mathematically modeled\nusing incidence matrices in Boolean logic and density matrices in probability\ntheory. Then we cross the bridge to the density matrix treatment of the\nindefinite superposition states in quantum mechanics (QM). This connection\nbetween the #2 abstracts in mathematics and ontic indefinite states in QM\nelucidates Abner Shimony's literal or objective indefiniteness interpretation\nof QM.\n",
"title": "From Abstract Entities in Mathematics to Superposition States in Quantum Mechanics"
}
| null | null | null | null | true | null |
12708
| null |
Default
| null | null |
null |
{
"abstract": " In this short note we explain the proof that proper surjective and faithfully\nflat maps are morphisms of effective descent for overconvergent isocrystals. We\nthen show how to deduce the folklore theorem that for an arbitrary variety over\na perfect field of characteristic $p$, the Frobenius pull-back functor is an\nequivalence on the overconvergent category.\n",
"title": "A note on effective descent for overconvergent isocrystals"
}
| null | null | null | null | true | null |
12709
| null |
Default
| null | null |
null |
{
"abstract": " We prove the Banach strong Novikov conjecture for groups having polynomially\nbounded higher-order combinatorial functions. This includes all automatic\ngroups.\n",
"title": "Banach strong Novikov conjecture for polynomially contractible groups"
}
| null | null | null | null | true | null |
12710
| null |
Default
| null | null |
null |
{
"abstract": " A reliable and consistently reproducible technique to fabricate\n$^{222}$Rn-loaded radioactive sources ($\\sim$0.5-1 kBq just after fabrication)\nbased on liquid scintillator (LS), with negligible amounts of LS quencher\ncontaminants, was implemented. This work demonstrates the process that will be\nused during the Borexino detector's upcoming calibration campaign, with one or\nseveral $\\sim$100 Bq such sources will be deployed at different positions in\nits fiducial volume, currently showing unprecedented levels of radiopurity.\nThese sources need to fulfill stringent requirements of $^{222}$Rn activity,\ntransparency to the radiations of interest and complete removability from the\ndetector to ensure their impact on Borexino's radiopurity is negligible.\nMoreover, the need for a clean, undistorted spectral signal for the\ncalibrations imposes a tight requirement to minimize quenching agents\n(\"quenchers\") to null or extremely low levels.\n",
"title": "Fabrication of quencher-free liquid scintillator-based, high-activity $^{222}$Rn calibration sources for the Borexino detector"
}
| null | null | null | null | true | null |
12711
| null |
Default
| null | null |
null |
{
"abstract": " This research was conducted to develop a method to identify voice utterance.\nFor voice utterance that encounters change caused by aging factor, with the\ninterval of 10 to 25 years. The change of voice utterance influenced by aging\nfactor might be extracted by MFCC (Mel Frequency Cepstrum Coefficient).\nHowever, the level of the compatibility of the feature may be dropped down to\n55%. While the ones which do not encounter it may reach 95%. To improve the\ncompatibility of the changing voice feature influenced by aging factor, then\nthe method of the more specific feature extraction is developed: which is by\nseparating the voice into several channels, suggested as MFCC multichannel,\nconsisting of multichannel 5 filterbank (M5FB), multichannel 2 filterbank\n(M2FB) and multichannel 1 filterbank (M1FB). The result of the test shows that\nfor model M5FB and M2FB have the highest score in the level of compatibility\nwith 85% and 82% with 25 years interval. While model M5FB gets the highest\nscore of 86% for 10 years time interval.\n",
"title": "Identification of Voice Utterance with Aging Factor Using the Method of MFCC Multichannel"
}
| null | null |
[
"Computer Science"
] | null | true | null |
12712
| null |
Validated
| null | null |
null |
{
"abstract": " We study finite alphabet channels with Unit Memory on the previous Channel\nOutputs called UMCO channels. We identify necessary and sufficient conditions,\nto test whether the capacity achieving channel input distributions with\nfeedback are time-invariant, and whether feedback capacity is characterized by\nsingle letter, expressions, similar to that of memoryless channels. The method\nis based on showing that a certain dynamic programming equation, which in\ngeneral, is a nested optimization problem over the sequence of channel input\ndistributions, reduces to a non-nested optimization problem. Moreover, for UMCO\nchannels, we give a simple expression for the ML error exponent, and we\nidentify sufficient conditions to test whether feedback does not increase\ncapacity. We derive similar results, when transmission cost constraints are\nimposed. We apply the results to a special class of the UMCO channels, the\nBinary State Symmetric Channel (BSSC) with and without transmission cost\nconstraints, to show that the optimization problem of feedback capacity is\nnon-nested, the capacity achieving channel input distribution and the\ncorresponding channel output transition probability distribution are\ntime-invariant, and feedback capacity is characterized by a single letter\nformulae, precisely as Shannon's single letter characterization of capacity of\nmemoryless channels. Then we derive closed form expressions for the capacity\nachieving channel input distribution and feedback capacity. We use the closed\nform expressions to evaluate an error exponent for ML decoding.\n",
"title": "Single Letter Expression of Capacity for a Class of Channels with Memory"
}
| null | null | null | null | true | null |
12713
| null |
Default
| null | null |
null |
{
"abstract": " Consider a quadratic vector field on $\\mathbb{C}^2$ having an invariant line\nat infinity and isolated singularities only. We define the extended spectra of\nsingularities to be the collection of the spectra of the linearization matrices\nof each of the singular points over the affine part, together with all the\ncharacteristic numbers (i.e. Camacho-Sad indices) at infinity. This collection\nconsists of 11 complex numbers, and is invariant under affine equivalence of\nvector fields.\nIn this paper we describe all polynomial relations among these numbers. There\nare 5 independent polynomial relations; four of them follow from the\nEuler-Jacobi, the Baum-Bott and the Camacho-Sad index theorems, and are well\nknown. The fifth relation was, until now, completely unknown. We provide an\nexplicit formula for the missing 5th relation, discuss it's meaning and prove\nthat it cannot be formulated as an index theorem.\n",
"title": "Spectra of quadratic vector fields on $\\mathbb{C}^2$: The missing relation"
}
| null | null | null | null | true | null |
12714
| null |
Default
| null | null |
null |
{
"abstract": " We design, conduct and present the results of a highly personalized baseline\nemotion recognition experiment, which aims to set reliable ground-truth\nestimates for the subject's emotional state for real-life prediction under\nsimilar conditions using a small number of physiological sensors. We also\npropose an adaptive stimuli-selection mechanism that would use the user's\nfeedback as guide for future stimuli selection in the controlled-setup\nexperiment and generate optimal ground-truth personalized sessions\nsystematically. Initial results are very promising (85% accuracy) and variable\nimportance analysis shows that only a few features, which are easy-to-implement\nin portable devices, would suffice to predict the subject's emotional state.\n",
"title": "A Controlled Set-Up Experiment to Establish Personalized Baselines for Real-Life Emotion Recognition"
}
| null | null |
[
"Computer Science",
"Statistics"
] | null | true | null |
12715
| null |
Validated
| null | null |
null |
{
"abstract": " We prove that along any marked point the Green function of a meromorphic\nfamily of polynomials parameterized by the punctured unit disk explodes\nexponentially fast near the origin with a continuous error term.\n",
"title": "Continuity of the Green function in meromorphic families of polynomials"
}
| null | null | null | null | true | null |
12716
| null |
Default
| null | null |
null |
{
"abstract": " This paper sets up a framework for designing a massive multiple-input\nmultiple-output (MIMO) testbed by investigating hardware (HW) and system-level\nrequirements such as processing complexity, duplexing mode and frame structure.\nTaking these into account, a generic system and processing partitioning is\nproposed which allows flexible scaling and processing distribution onto a\nmultitude of physically separated devices. Based on the given HW constraints\nsuch as maximum number of links and maximum throughput for peer-to-peer\ninterconnections combined with processing capabilities, the framework allows to\nevaluate modular HW components. To verify our design approach, we present the\nLuMaMi (Lund University Massive MIMO) testbed which constitutes the first\nreconfigurable real-time HW platform for prototyping massive MIMO. Utilizing up\nto 100 base station antennas and more than 50 Field Programmable Gate Arrays,\nup to 12 user equipments are served on the same time/frequency resource using\nan LTE-like Orthogonal Frequency Division Multiplexing time-division\nduplex-based transmission scheme. Proof-of-concept tests with this system show\nthat massive MIMO can simultaneously serve a multitude of users in a static\nindoor and static outdoor environment utilizing the same time/frequency\nresource.\n",
"title": "The World's First Real-Time Testbed for Massive MIMO: Design, Implementation, and Validation"
}
| null | null | null | null | true | null |
12717
| null |
Default
| null | null |
null |
{
"abstract": " The problem of how to coordinate a large fleet of trucks with given itinerary\nto enable fuel-efficient platooning is considered. Platooning is a promising\ntechnology that enables trucks to save significant amounts of fuel by driving\nclose together and thus reducing air drag. A setting is considered in which\neach truck in a fleet is provided with a start location, a destination, a\ndeparture time, and an arrival deadline from a higher planning level.\nFuel-efficient plans should be computed. The plans consist of routes and speed\nprofiles that allow trucks to arrive by their arrival deadlines. Hereby, trucks\ncan meet on common parts of their routes and form platoons, resulting in\ndecreased fuel consumption.\nWe formulate a combinatorial optimization problem that combines plans\ninvolving only two vehicles. We show that this problem is hard to solve for\nlarge problem instances. Hence a heuristic algorithm is proposed. The resulting\nplans are further optimized using convex optimization techniques. The method is\nevaluated with Monte Carlo simulations in a realistic setting. We demonstrate\nthat the proposed algorithm can compute plans for thousands of trucks and that\nsignificant fuel savings can be achieved.\n",
"title": "Fuel-Efficient En Route Formation of Truck Platoons"
}
| null | null | null | null | true | null |
12718
| null |
Default
| null | null |
null |
{
"abstract": " Many of the recent approaches to polyphonic piano note onset transcription\nrequire training a machine learning model on a large piano database. However,\nsuch approaches are limited by dataset availability; additional training data\nis difficult to produce, and proposed systems often perform poorly on novel\nrecording conditions. We propose a method to quickly synthesize arbitrary\nquantities of training data, avoiding the need for curating large datasets.\nVarious aspects of piano note dynamics - including nonlinearity of note\nsignatures with velocity, different articulations, temporal clustering of\nonsets, and nonlinear note partial interference - are modeled to match the\ncharacteristics of real pianos. Our method also avoids the disentanglement\nproblem, a recently noted issue affecting machine-learning based approaches. We\ntrain a feed-forward neural network with two hidden layers on our generated\ntraining data and achieve both good transcription performance on the large MAPS\npiano dataset and excellent generalization qualities.\n",
"title": "Context-Independent Polyphonic Piano Onset Transcription with an Infinite Training Dataset"
}
| null | null | null | null | true | null |
12719
| null |
Default
| null | null |
null |
{
"abstract": " The family of Multiscale Hybrid-Mixed (MHM) finite element methods has\nreceived considerable attention from the mathematics and engineering community\nin the last few years. The MHM methods allow solving highly heterogeneous\nproblems on coarse meshes while providing solutions with high-order precision.\nIt embeds independent local problems which are responsible for upscaling\nunresolved scales into the numerical solution. These local contributions are\nbrought together through a global problem defined on the skeleton of the coarse\npartition. Since the local problems are completely independent, they can be\neasily computed in parallel. In this paper, we present two simulator prototypes\nspecifically crafted for the MHM methods, which adopt two different\nimplementation strategies: (i) a multi-programming language approach, each\nlanguage tackling different simulation issues; and (ii) a classical,\nsingle-programming language approach. Specifically, we use C++ for numerical\ncomputation of the global and local problems in a modular way; for process\ndistribution in the simulator, we adopt the Erlang concurrent language in the\nfirst approach, and the MPI standard in the second approach. The aim of\nexploring these different approaches is twofold: (i) allow for the deployment\nof the simulator both in high-performance computing (with MPI) and in cloud\ncomputing environments (with Erlang); and (ii) pave the way for further\nexploration of quality attributes related to software productivity and\nfault-tolerance, which are key to Exascale systems. We present a performance\nevaluation of the two simulator prototypes taking into account their\nefficiency.\n",
"title": "On the Implementation of a Scalable Simulator for Multiscale Hybrid-Mixed Methods"
}
| null | null | null | null | true | null |
12720
| null |
Default
| null | null |
null |
{
"abstract": " Associated with every quaternionic representation of a compact, connected Lie\ngroup there is a Seiberg-Witten equation in dimension three. The moduli spaces\nof solutions to these equations are typically non-compact. We construct\nKuranishi models around boundary points of a partially compactified moduli\nspace. The Haydys correspondence identifies such boundary points with Fueter\nsections - solutions of a non-linear Dirac equation - of the bundle of\nhyperkähler quotients associated with the quaternionic representation. We\ndiscuss when such a Fueter section can be deformed to a solution of the\nSeiberg-Witten equation.\n",
"title": "Deformation theory of the blown-up Seiberg-Witten equation in dimension three"
}
| null | null | null | null | true | null |
12721
| null |
Default
| null | null |
null |
{
"abstract": " The model studied in this paper is a stochastic extension of the so-called\nneuron model introduced by Hodgkin and Huxley. In the sense of rough paths, the\nmodel is perturbed by a multiplicative noise driven by a fractional Brownian\nmotion, with a vector field satisfying the viability condition of Coutin and\nMarie for $\\mathbb R\\times [0,1]^3$. An application to the modeling of the\nmembrane potential of nerve fibers damaged by a neuropathy is provided.\n",
"title": "On a Fractional Stochastic Hodgkin-Huxley Model"
}
| null | null | null | null | true | null |
12722
| null |
Default
| null | null |
null |
{
"abstract": " Compared to basic fork-join queues, a job in (n, k) fork-join queues only\nneeds its k out of all n sub-tasks to be finished. Since (n, k) fork-join\nqueues are prevalent in popular distributed systems, erasure coding based cloud\nstorages, and modern network protocols like multipath routing, estimating the\nsojourn time of such queues is thus critical for the performance measurement\nand resource plan of computer clusters. However, the estimating keeps to be a\nwell-known open challenge for years, and only rough bounds for a limited range\nof load factors have been given. In this paper, we developed a closed-form\nlinear transformation technique for jointly-identical random variables: An\norder statistic can be represented by a linear combination of maxima. This\nbrand-new technique is then used to transform the sojourn time of non-purging\n(n, k) fork-join queues into a linear combination of the sojourn times of basic\n(k, k), (k+1, k+1), ..., (n, n) fork-join queues. Consequently, existing\napproximations for basic fork-join queues can be bridged to the approximations\nfor non-purging (n, k) fork-join queues. The uncovered approximations are then\nused to improve the upper bounds for purging (n, k) fork-join queues.\nSimulation experiments show that this linear transformation approach is\npracticed well for moderate n and relatively large k.\n",
"title": "Approximations and Bounds for (n, k) Fork-Join Queues: A Linear Transformation Approach"
}
| null | null | null | null | true | null |
12723
| null |
Default
| null | null |
null |
{
"abstract": " In elastic-wave turbulence, strong turbulence appears in small wave numbers\nwhile weak turbulence does in large wave numbers. Energy transfers in the\ncoexistence of these turbulent states are numerically investigated in both of\nthe Fourier space and the real space. An analytical expression of a detailed\nenergy balance reveals from which mode to which mode energy is transferred in\nthe triad interaction. Stretching energy excited by external force is\ntransferred nonlocally and intermittently to large wave numbers as the kinetic\nenergy in the strong turbulence. In the weak turbulence, the resonant\ninteractions according to the weak turbulence theory produces cascading net\nenergy transfer to large wave numbers. Because the system's nonlinearity shows\nstrong temporal intermittency, the energy transfers are investigated at active\nand moderate phases separately. The nonlocal interactions in the Fourier space\nare characterized by the intermittent bundles of fibrous structures in the real\nspace.\n",
"title": "Integrated analysis of energy transfers in elastic-wave turbulence"
}
| null | null |
[
"Physics"
] | null | true | null |
12724
| null |
Validated
| null | null |
null |
{
"abstract": " We report on the magnetic properties of zinc ferrite thin film deposited on\nSrTiO$_3$ single crystal using pulsed laser deposition. X-ray diffraction\nresult indicates the highly oriented single phase growth of the film along with\nthe presence of the strain. In comparison to the bulk antiferromagnetic order,\nthe as-deposited film has been found to exhibit ferrimagnetic ordering with a\ncoercive field of 1140~Oe at 5~K. A broad maximum, at $\\approx$105~K, observed\nin zero-field cooled magnetization curve indicates the wide grain size\ndistribution for the as-deposited film. Reduction in magnetization and blocking\ntemperature has been observed after annealing in both argon as well as oxygen\natmospheres, where the variation was found to be dependent on the annealing\ntemperature.\n",
"title": "Effect of annealing on the magnetic properties of zinc ferrite thin films"
}
| null | null | null | null | true | null |
12725
| null |
Default
| null | null |
null |
{
"abstract": " In this paper, we present the LSF parameters by a unit vector form, which has\ndirectional characteristics. The underlying distribution of this unit vector\nvariable is modeled by a von Mises-Fisher mixture model (VMM). With the high\nrate theory, the optimal inter-component bit allocation strategy is proposed\nand the distortion-rate (D-R) relation is derived for the VMM based-VQ (VVQ).\nExperimental results show that the VVQ outperforms our recently introduced DVQ\nand the conventional GVQ.\n",
"title": "Statistical Speech Model Description with VMF Mixture Model"
}
| null | null | null | null | true | null |
12726
| null |
Default
| null | null |
null |
{
"abstract": " We show that a newly proposed Shannon-like entropic measure of shape\ncomplexity applicable to spatially-localized or periodic mathematical functions\nknown as configurational entropy (CE) can be used as a predictor of spontaneous\ndecay rates for one-electron atoms. The CE is constructed from the Fourier\ntransform of the atomic probability density. For the hydrogen atom with\ndegenerate states labeled with the principal quantum number n, we obtain a\nscaling law relating the n-averaged decay rates to the respective CE. The\nscaling law allows us to predict the n-averaged decay rate without relying on\nthe traditional computation of dipole matrix elements. We tested the predictive\npower of our approach up to n=20, obtaining an accuracy better than 3.7% within\nour numerical precision, as compared to spontaneous decay tables listed in the\nliterature.\n",
"title": "Predicting Atomic Decay Rates Using an Informational-Entropic Approach"
}
| null | null | null | null | true | null |
12727
| null |
Default
| null | null |
null |
{
"abstract": " A new second-order numerical scheme based on an operator splitting is\nproposed for the Godunov-Peshkov-Romenski model of continuum mechanics. The\nhomogeneous part of the system is solved with a finite volume method based on a\nWENO reconstruction, and the temporal ODEs are solved using some analytic\nresults presented here. Whilst it is not possible to attain arbitrary-order\naccuracy with this scheme (as with ADER-WENO schemes used previously), the\nattainable order of accuracy is often sufficient, and solutions are\ncomputationally cheap when compared with other available schemes. The new\nscheme is compared with an ADER-WENO scheme for various test cases, and a\nconvergence study is undertaken to demonstrate its order of accuracy.\n",
"title": "A Fast Numerical Scheme for the Godunov-Peshkov-Romenski Model of Continuum Mechanics"
}
| null | null | null | null | true | null |
12728
| null |
Default
| null | null |
null |
{
"abstract": " Explaining and reasoning about processes which underlie observed black-box\nphenomena enables the discovery of causal mechanisms, derivation of suitable\nabstract representations and the formulation of more robust predictions. We\npropose to learn high level functional programs in order to represent abstract\nmodels which capture the invariant structure in the observed data. We introduce\nthe $\\pi$-machine (program-induction machine) -- an architecture able to induce\ninterpretable LISP-like programs from observed data traces. We propose an\noptimisation procedure for program learning based on backpropagation, gradient\ndescent and A* search. We apply the proposed method to three problems: system\nidentification of dynamical systems, explaining the behaviour of a DQN agent\nand learning by demonstration in a human-robot interaction scenario. Our\nexperimental results show that the $\\pi$-machine can efficiently induce\ninterpretable programs from individual data traces.\n",
"title": "Explaining Transition Systems through Program Induction"
}
| null | null | null | null | true | null |
12729
| null |
Default
| null | null |
null |
{
"abstract": " Distributed algorithms are often beset by the straggler effect, where the\nslowest compute nodes in the system dictate the overall running time.\nCoding-theoretic techniques have been recently proposed to mitigate stragglers\nvia algorithmic redundancy. Prior work in coded computation and gradient coding\nhas mainly focused on exact recovery of the desired output. However, slightly\ninexact solutions can be acceptable in applications that are robust to noise,\nsuch as model training via gradient-based algorithms. In this work, we present\ncomputationally simple gradient codes based on sparse graphs that guarantee\nfast and approximately accurate distributed computation. We demonstrate that\nsacrificing a small amount of accuracy can significantly increase algorithmic\nrobustness to stragglers.\n",
"title": "Approximate Gradient Coding via Sparse Random Graphs"
}
| null | null | null | null | true | null |
12730
| null |
Default
| null | null |
null |
{
"abstract": " Most popular word embedding techniques involve implicit or explicit\nfactorization of a word co-occurrence based matrix into low rank factors. In\nthis paper, we aim to generalize this trend by using numerical methods to\nfactor higher-order word co-occurrence based arrays, or \\textit{tensors}. We\npresent four word embeddings using tensor factorization and analyze their\nadvantages and disadvantages. One of our main contributions is a novel joint\nsymmetric tensor factorization technique related to the idea of coupled tensor\nfactorization. We show that embeddings based on tensor factorization can be\nused to discern the various meanings of polysemous words without being\nexplicitly trained to do so, and motivate the intuition behind why this works\nin a way that doesn't with existing methods. We also modify an existing word\nembedding evaluation metric known as Outlier Detection [Camacho-Collados and\nNavigli, 2016] to evaluate the quality of the order-$N$ relations that a word\nembedding captures, and show that tensor-based methods outperform existing\nmatrix-based methods at this task. Experimentally, we show that all of our word\nembeddings either outperform or are competitive with state-of-the-art baselines\ncommonly used today on a variety of recent datasets. Suggested applications of\ntensor factorization-based word embeddings are given, and all source code and\npre-trained vectors are publicly available online.\n",
"title": "Word Embeddings via Tensor Factorization"
}
| null | null |
[
"Computer Science",
"Statistics"
] | null | true | null |
12731
| null |
Validated
| null | null |
null |
{
"abstract": " Let $M$ be a compact constant mean curvature surface either in $\\mathbb{S}^3$\nor $\\mathbb{R}^3$. In this paper we prove that the stability index of $M$ is\nbounded below by a linear function of the genus. As a by product we obtain a\ncomparison theorem between the spectrum of the Jacobi operator of $M$ and those\nof Hodge Laplacian of $1$-forms on $M$.\n",
"title": "Lower bounds for the index of compact constant mean curvature surfaces in $\\mathbb R^{3}$ and $\\mathbb S^{3}$"
}
| null | null | null | null | true | null |
12732
| null |
Default
| null | null |
null |
{
"abstract": " In this paper, we discuss the maximum principle for a time-fractional\ndiffusion equation $$ \\partial_t^\\alpha u(x,t) = \\sum_{i,j=1}^n\n\\partial_i(a_{ij}(x)\\partial_j u(x,t)) + c(x)u(x,t) + F(x,t),\\ t>0,\\ x \\in\n\\Omega \\subset {\\mathbb R}^n$$ with the Caputo time-derivative of the order\n$\\alpha \\in (0,1)$ in the case of the homogeneous Dirichlet boundary condition.\nCompared to the already published results, our findings have two important\nspecial features. First, we derive a maximum principle for a suitably defined\nweak solution in the fractional Sobolev spaces, not for the strong solution.\nSecond, for the non-negative source functions $F = F(x,t)$ we prove the\nnon-negativity of the weak solution to the problem under consideration without\nany restrictions on the sign of the coefficient $c=c(x)$ by the derivative of\norder zero in the spatial differential operator. Moreover, we prove the\nmonotonicity of the solution with respect to the coefficient $c=c(x)$.\n",
"title": "On the maximum principle for a time-fractional diffusion equation"
}
| null | null | null | null | true | null |
12733
| null |
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| null | null |
null |
{
"abstract": " The structure and nature of water confined between hydrophobic molybdenum\ndisulfide (MoS2) and graphene (Gr) are investigated at room temperature by\nmeans of atomic force microscopy. We find the formation of two-dimensional (2D)\ncrystalline ice layers. In contrast to the hexagonal ice 'bilayers' of bulk\nice, these 2D crystalline ice phases consist of two planar hexagonal layers.\nAdditional water condensation leads to either lateral expansion of the ice\nlayers or to the formation of three-dimensional water droplets on top or at the\nedges of the two-layer ice, indicating that water does not wet these planar ice\nfilms. The results presented here are in line with a recent theory suggesting\nthat water confined between hydrophobic walls forms 2D crystalline two-layer\nice with a nontetrahedral geometry and intrahydrogen bonding. The lack of\ndangling bonds on either surface of the ice film gives rise to a hydrophobic\ncharacter. The unusual geometry of these ice films is of great potential\nimportance in biological systems with water in direct contact with hydrophobic\nsurfaces.\n",
"title": "Hydrophobic Ice Confined between Graphene and MoS2"
}
| null | null | null | null | true | null |
12734
| null |
Default
| null | null |
null |
{
"abstract": " Although the motility of the flagellated bacteria, Escherichia coli, has been\nwidely studied, the effect of viscosity on swimming speed remains\ncontroversial. The swimming mode of wild-type E.coli is often idealized as a\n\"run-and- tumble\" sequence in which periods of swimming at a constant speed are\nrandomly interrupted by a sudden change of direction at a very low speed. Using\na tracking microscope, we follow cells for extended periods of time in\nNewtonian liquids of varying viscosity, and find that the swimming behavior of\na single cell can exhibit a variety of behaviors including run-and-tumble and\n\"slow-random-walk\" in which the cells move at relatively low speed. Although\nthe characteristic swimming speed varies between individuals and in different\npolymer solutions, we find that the skewness of the speed distribution is\nsolely a function of viscosity and can be used, in concert with the measured\naverage swimming speed, to determine the effective running speed of each cell.\nWe hypothesize that differences in the swimming behavior observed in solutions\nof different viscosity are due to changes in the flagellar bundling time, which\nincreases as the viscosity rises, due to the lower rotation rate of the\nflagellar motor. A numerical simulation and the use of Resistive Force theory\nprovide support for this hypothesis.\n",
"title": "Changes in the flagellar bundling time account for variations in swimming behavior of flagellated bacteria in viscous media"
}
| null | null | null | null | true | null |
12735
| null |
Default
| null | null |
null |
{
"abstract": " Data-driven brain parcellations aim to provide a more accurate representation\nof an individual's functional connectivity, since they are able to capture\nindividual variability that arises due to development or disease. This renders\ncomparisons between the emerging brain connectivity networks more challenging,\nsince correspondences between their elements are not preserved. Unveiling these\ncorrespondences is of major importance to keep track of local functional\nconnectivity changes. We propose a novel method based on graph edit distance\nfor the comparison of brain graphs directly in their domain, that can\naccurately reflect similarities between individual networks while providing the\nnetwork element correspondences. This method is validated on a dataset of 116\ntwin subjects provided by the Human Connectome Project.\n",
"title": "Exploring Heritability of Functional Brain Networks with Inexact Graph Matching"
}
| null | null | null | null | true | null |
12736
| null |
Default
| null | null |
null |
{
"abstract": " In this paper, dark energy models of the universe filled with wet dark fluid\nare constructed in the framework of LRS Bianchi type-II space-time in General\nTheory of Relativity. A new equation of state modeled on the equation of state\n$p$=$\\gamma(\\rho - \\rho_*)$, which can describe a liquid including water, is\nused. The exact solutions of Einstein's field equations are obtained in\nquadrature form and the models corresponding to the cases $\\gamma = 0$ and\n$\\gamma = 1$ are discussed in detail.\n",
"title": "Bianchi type-II universe with wet dark fluid in General Theory of Relativity"
}
| null | null | null | null | true | null |
12737
| null |
Default
| null | null |
null |
{
"abstract": " We obtain the solutions of the generic bilinear master equation for a quantum\noscillator with constant coefficients in the Gaussian form. The\nwell-behavedness and positive semidefiniteness of the stationary states could\nbe characterized by a three-dimensional Minkowski vector. By requiring the\nstationary states to satisfy a factorized condition, we obtain a generic class\nof master equations that includes the well-known ones and their\ngeneralizations, some of which are completely positive. A further subset of the\nmaster equations with the Gibbs states as stationary states is also obtained.\nFor master equations with not completely positive generators, an analysis on\nthe stationary states suggests conditions on the coefficients of the master\nequations that generate positive evolution for a given initial state.\n",
"title": "Solutions of generic bilinear master equations for a quantum oscillator -- positive and factorized conditions on stationary states"
}
| null | null | null | null | true | null |
12738
| null |
Default
| null | null |
null |
{
"abstract": " Semantic instance segmentation remains a challenging task. In this work we\npropose to tackle the problem with a discriminative loss function, operating at\nthe pixel level, that encourages a convolutional network to produce a\nrepresentation of the image that can easily be clustered into instances with a\nsimple post-processing step. The loss function encourages the network to map\neach pixel to a point in feature space so that pixels belonging to the same\ninstance lie close together while different instances are separated by a wide\nmargin. Our approach of combining an off-the-shelf network with a principled\nloss function inspired by a metric learning objective is conceptually simple\nand distinct from recent efforts in instance segmentation. In contrast to\nprevious works, our method does not rely on object proposals or recurrent\nmechanisms. A key contribution of our work is to demonstrate that such a simple\nsetup without bells and whistles is effective and can perform on par with more\ncomplex methods. Moreover, we show that it does not suffer from some of the\nlimitations of the popular detect-and-segment approaches. We achieve\ncompetitive performance on the Cityscapes and CVPPP leaf segmentation\nbenchmarks.\n",
"title": "Semantic Instance Segmentation with a Discriminative Loss Function"
}
| null | null | null | null | true | null |
12739
| null |
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| null | null |
null |
{
"abstract": " Imbalanced data with a skewed class distribution are common in many\nreal-world applications. Deep Belief Network (DBN) is a machine learning\ntechnique that is effective in classification tasks. However, conventional DBN\ndoes not work well for imbalanced data classification because it assumes equal\ncosts for each class. To deal with this problem, cost-sensitive approaches\nassign different misclassification costs for different classes without\ndisrupting the true data sample distributions. However, due to lack of prior\nknowledge, the misclassification costs are usually unknown and hard to choose\nin practice. Moreover, it has not been well studied as to how cost-sensitive\nlearning could improve DBN performance on imbalanced data problems. This paper\nproposes an evolutionary cost-sensitive deep belief network (ECS-DBN) for\nimbalanced classification. ECS-DBN uses adaptive differential evolution to\noptimize the misclassification costs based on training data, that presents an\neffective approach to incorporating the evaluation measure (i.e. G-mean) into\nthe objective function. We first optimize the misclassification costs, then\napply them to deep belief network. Adaptive differential evolution optimization\nis implemented as the optimization algorithm that automatically updates its\ncorresponding parameters without the need of prior domain knowledge. The\nexperiments have shown that the proposed approach consistently outperforms the\nstate-of-the-art on both benchmark datasets and real-world dataset for fault\ndiagnosis in tool condition monitoring.\n",
"title": "A Cost-Sensitive Deep Belief Network for Imbalanced Classification"
}
| null | null | null | null | true | null |
12740
| null |
Default
| null | null |
null |
{
"abstract": " In this paper, we introduce a new variant of the $p$-median facility location\nproblem in which it is assumed that the exact location of the potential\nfacilities is unknown. Instead, each of the facilities must be located in a\nregion around their initially assigned location (the neighborhood). In this\nproblem, two main decisions have to be made simultaneously: the determination\nof the potential facilities that must be open to serve the demands of the\ncustomers and the location of the open facilities in their neighborhoods, at\nglobal minimum cost. We present several mixed integer non-linear programming\nformulations for a wide family of objective functions which are common in\nLocation Analysis: ordered median functions. We also develop two math-heuristic\napproaches for solving the problem. We report the results of extensive\ncomputational experiments.\n",
"title": "Ordered p-median problems with neighborhoods"
}
| null | null |
[
"Mathematics"
] | null | true | null |
12741
| null |
Validated
| null | null |
null |
{
"abstract": " We define multi-block interleaved codes as codes that allow reading\ninformation from either a small sub-block or from a larger full block. The\nformer offers faster access, while the latter provides better reliability. We\nspecify the correction capability of the sub-block code through its gap $t$\nfrom optimal minimum distance, and look to have full-block minimum distance\nthat grows with the parameter $t$. We construct two families of such codes when\nthe number of sub-blocks is $3$. The codes match the distance properties of\nknown integrated-interleaving codes, but with the added feature of mapping the\nsame number of information symbols to each sub-block. As such, they are the\nfirst codes that provide read access in multiple size granularities and\ncorrection capabilities.\n",
"title": "Multi-Block Interleaved Codes for Local and Global Read Access"
}
| null | null | null | null | true | null |
12742
| null |
Default
| null | null |
null |
{
"abstract": " This paper proposes a new method for solving the well-known rank aggregation\nproblem from pairwise comparisons using the method of low-rank matrix\ncompletion. The partial and noisy data of pairwise comparisons is transformed\ninto a matrix form. We then use tools from matrix completion, which has served\nas a major component in the low-rank completion solution of the Netflix\nchallenge, to construct the preference of the different objects. In our\napproach, the data of multiple comparisons is used to create an estimate of the\nprobability of object i to win (or be chosen) over object j, where only a\npartial set of comparisons between N objects is known. The data is then\ntransformed into a matrix form for which the noiseless solution has a known\nrank of one. An alternating minimization algorithm, in which the target matrix\ntakes a bilinear form, is then used in combination with maximum likelihood\nestimation for both factors. The reconstructed matrix is used to obtain the\ntrue underlying preference intensity. This work demonstrates the improvement of\nour proposed algorithm over the current state-of-the-art in both simulated\nscenarios and real data.\n",
"title": "Ranking Recovery from Limited Comparisons using Low-Rank Matrix Completion"
}
| null | null | null | null | true | null |
12743
| null |
Default
| null | null |
null |
{
"abstract": " In this paper we study the probability distribution of the position of a\ntagged particle in the $q$-deformed Totally Asymmetric Zero Range Process\n($q$-TAZRP) with site dependent jumping rates. For a finite particle system, it\nis derived from the transition probability previously obtained by Wang and\nWaugh. We also provide the probability distribution formula for a tagged\nparticle in the $q$-TAZRP with the so-called step initial condition in which\ninfinitely many particles occupy one single site and all other sites are\nunoccupied. For the $q$-TAZRP with step initial condition, we provide a\nFredholm determinant representation for the probability distribution function\nof the position of a tagged particle, and moreover we obtain the limiting\ndistribution function as the time goes to infinity. Our asymptotic result for\n$q$-TAZRP with step initial condition is comparable to the limiting\ndistribution function obtained by Tracy and Widom for the $k$-th leftmost\nparticle in the asymmetric simple exclusion process with step initial condition\n(Theorem 2 in Commun. Math. Phys. 290, 129--154 (2009)).\n",
"title": "Distributions of a particle's position and their asymptotics in the $q$-deformed totally asymmetric zero range process with site dependent jumping rates"
}
| null | null | null | null | true | null |
12744
| null |
Default
| null | null |
null |
{
"abstract": " The magnetoelectric effects in the surface states of the 3D TI are extremely\nstrong due to the full spin-momentum locking. Here the microscopic theory of\nS/3D TI bilayer structures in terms of quasiclassical Green's functions is\ndeveloped. On the basis of the developed formalism it is shown that the DOS in\nthe S/TI bilayer manifests giant magnetoelectric behavior and, as a result,\nS/3D TI heterostructures can work as non-magnetic fully electrically\ncontrollable spin filters. It is shown that due to the full spin-momentum\nlocking the amplitudes of the odd-frequency singlet and triplet components of\nthe consensate wave function are equal. The same is valid for the even\nfrequency singlet and triplet components. We unveil the connection between the\nodd-frequency pairing in S/3D TI heterostructures and magnetoelectric effects\nin the DOS.\n",
"title": "Electrically controllable spin filtering based on superconducting helical states"
}
| null | null | null | null | true | null |
12745
| null |
Default
| null | null |
null |
{
"abstract": " Recent progress in logic programming (e.g., the development of the Answer Set\nProgramming paradigm) has made it possible to teach it to general undergraduate\nand even high school students. Given the limited exposure of these students to\ncomputer science, the complexity of downloading, installing and using tools for\nwriting logic programs could be a major barrier for logic programming to reach\na much wider audience. We developed an online answer set programming\nenvironment with a self contained file system and a simple interface, allowing\nusers to write logic programs and perform several tasks over the programs.\n",
"title": "An Online Development Environment for Answer Set Programming"
}
| null | null | null | null | true | null |
12746
| null |
Default
| null | null |
null |
{
"abstract": " This paper studies improving solvers based on their past solving experiences,\nand focuses on improving solvers by offline training. Specifically, the key\nissues of offline training methods are discussed, and research belonging to\nthis category but from different areas are reviewed in a unified framework.\nExisting training methods generally adopt a two-stage strategy in which\nselecting the training instances and training instances are treated in two\nindependent phases. This paper proposes a new training method, dubbed LiangYi,\nwhich addresses these two issues simultaneously. LiangYi includes a training\nmodule for a population-based solver and an instance sampling module for\nupdating the training instances. The idea behind LiangYi is to promote the\npopulation-based solver by training it (with the training module) to improve\nits performance on those instances (discovered by the sampling module) on which\nit performs badly, while keeping the good performances obtained by it on\nprevious instances. An instantiation of LiangYi on the Travelling Salesman\nProblem is also proposed. Empirical results on a huge testing set containing\n10000 instances showed LiangYi could train solvers that perform significantly\nbetter than the solvers trained by other state-of-the-art training method.\nMoreover, empirical investigation of the behaviours of LiangYi confirmed it was\nable to continuously improve the solver through training.\n",
"title": "Experience-based Optimization: A Coevolutionary Approach"
}
| null | null | null | null | true | null |
12747
| null |
Default
| null | null |
null |
{
"abstract": " Online social networking sites are experimenting with the following\ncrowd-powered procedure to reduce the spread of fake news and misinformation:\nwhenever a user is exposed to a story through her feed, she can flag the story\nas misinformation and, if the story receives enough flags, it is sent to a\ntrusted third party for fact checking. If this party identifies the story as\nmisinformation, it is marked as disputed. However, given the uncertain number\nof exposures, the high cost of fact checking, and the trade-off between flags\nand exposures, the above mentioned procedure requires careful reasoning and\nsmart algorithms which, to the best of our knowledge, do not exist to date.\nIn this paper, we first introduce a flexible representation of the above\nprocedure using the framework of marked temporal point processes. Then, we\ndevelop a scalable online algorithm, Curb, to select which stories to send for\nfact checking and when to do so to efficiently reduce the spread of\nmisinformation with provable guarantees. In doing so, we need to solve a novel\nstochastic optimal control problem for stochastic differential equations with\njumps, which is of independent interest. Experiments on two real-world datasets\ngathered from Twitter and Weibo show that our algorithm may be able to\neffectively reduce the spread of fake news and misinformation.\n",
"title": "Leveraging the Crowd to Detect and Reduce the Spread of Fake News and Misinformation"
}
| null | null | null | null | true | null |
12748
| null |
Default
| null | null |
null |
{
"abstract": " Bayesian optimization is proposed for automatic learning of optimal\ncontroller parameters from experimental data. A probabilistic description (a\nGaussian process) is used to model the unknown function from controller\nparameters to a user-defined cost. The probabilistic model is updated with\ndata, which is obtained by testing a set of parameters on the physical system\nand evaluating the cost. In order to learn fast, the Bayesian optimization\nalgorithm selects the next parameters to evaluate in a systematic way, for\nexample, by maximizing information gain about the optimum. The algorithm thus\niteratively finds the globally optimal parameters with only few experiments.\nTaking throttle valve control as a representative industrial control example,\nthe proposed auto-tuning method is shown to outperform manual calibration: it\nconsistently achieves better performance with a low number of experiments. The\nproposed auto-tuning framework is flexible and can handle different control\nstructures and objectives.\n",
"title": "Data-efficient Auto-tuning with Bayesian Optimization: An Industrial Control Study"
}
| null | null |
[
"Computer Science"
] | null | true | null |
12749
| null |
Validated
| null | null |
null |
{
"abstract": " This paper considers general rank-constrained optimization problems that\nminimize a general objective function $f(X)$ over the set of rectangular\n$n\\times m$ matrices that have rank at most $r$. To tackle the rank constraint\nand also to reduce the computational burden, we factorize $X$ into $UV^T$ where\n$U$ and $V$ are $n\\times r$ and $m\\times r$ matrices, respectively, and then\noptimize over the small matrices $U$ and $V$. We characterize the global\noptimization geometry of the nonconvex factored problem and show that the\ncorresponding objective function satisfies the robust strict saddle property as\nlong as the original objective function $f$ satisfies restricted strong\nconvexity and smoothness properties, ensuring global convergence of many local\nsearch algorithms (such as noisy gradient descent) in polynomial time for\nsolving the factored problem. We also provide a comprehensive analysis for the\noptimization geometry of a matrix factorization problem where we aim to find\n$n\\times r$ and $m\\times r$ matrices $U$ and $V$ such that $UV^T$ approximates\na given matrix $X^\\star$. Aside from the robust strict saddle property, we show\nthat the objective function of the matrix factorization problem has no spurious\nlocal minima and obeys the strict saddle property not only for the\nexact-parameterization case where $rank(X^\\star) = r$, but also for the\nover-parameterization case where $rank(X^\\star) < r$ and the\nunder-parameterization case where $rank(X^\\star) > r$. These geometric\nproperties imply that a number of iterative optimization algorithms (such as\ngradient descent) converge to a global solution with random initialization.\n",
"title": "The Global Optimization Geometry of Low-Rank Matrix Optimization"
}
| null | null | null | null | true | null |
12750
| null |
Default
| null | null |
null |
{
"abstract": " We study the problem of variable selection for linear models under the\nhigh-dimensional asymptotic setting, where the number of observations $n$ grows\nat the same rate as the number of predictors $p$. We consider two-stage\nvariable selection techniques (TVS) in which the first stage uses bridge\nestimators to obtain an estimate of the regression coefficients, and the second\nstage simply thresholds this estimate to select the \"important\" predictors. The\nasymptotic false discovery proportion (AFDP) and true positive proportion\n(ATPP) of these TVS are evaluated. We prove that for a fixed ATTP, in order to\nobtain a smaller AFDP, one should pick a bridge estimator with smaller\nasymptotic mean square error in the first stage of TVS. Based on such\nprincipled discovery, we present a sharp comparison of different TVS, via an\nin-depth investigation of the estimation properties of bridge estimators.\nRather than \"order-wise\" error bounds with loose constants, our analysis\nfocuses on precise error characterization. Various interesting signal-to-noise\nratio and sparsity settings are studied. Our results offer new and thorough\ninsights into high-dimensional variable selection. For instance, we prove that\na TVS with Ridge in its first stage outperforms TVS with other bridge\nestimators in large noise settings; two-stage LASSO becomes inferior when the\nsignal is rare and weak. As a by-product, we show our proposed two-stage\nmethods outperform some standard variable selection techniques, such as LASSO\nand Sure Independence Screening, under certain conditions.\n",
"title": "Which bridge estimator is optimal for variable selection?"
}
| null | null | null | null | true | null |
12751
| null |
Default
| null | null |
null |
{
"abstract": " Network systems and their control are highly important and appear in a\nvariety of applications, including vehicle platooning and formation con- trol.\nEspecially vehicle platoons are highly investigated and an interesting problem\nthat arises in this area is string stability, which broadly spoken means that a\ninput signal amplifies unbounded as it travels through the vehicle string.\nHowever, various definitions are commonly used. In this paper, we aim to\nformalise the notion of string stability and illustrate the importance of those\ndistinctions on simulation examples. A second goal is to generalise the found\ndefinitions for general network systems.\n",
"title": "Network Systems and String Stability"
}
| null | null | null | null | true | null |
12752
| null |
Default
| null | null |
null |
{
"abstract": " The function space of deep-learning machines is investigated by studying\ngrowth in the entropy of functions of a given error with respect to a reference\nfunction, realized by a deep-learning machine. Using physics-inspired methods\nwe study both sparsely and densely-connected architectures to discover a\nlayer-wise convergence of candidate functions, marked by a corresponding\nreduction in entropy when approaching the reference function, gain insight into\nthe importance of having a large number of layers, and observe phase\ntransitions as the error increases.\n",
"title": "Exploring the Function Space of Deep-Learning Machines"
}
| null | null | null | null | true | null |
12753
| null |
Default
| null | null |
null |
{
"abstract": " The object of study in the present dissertation are some topics in\ndifferential geometry of smooth manifolds with additional tensor structures and\nmetrics of Norden type. There are considered four cases depending on the\ndimension of the manifold: 2n, 2n + 1, 4n and 4n + 3. The studied tensor\nstructures, which are counterparts in the different related dimensions, are the\nalmost complex/contact/hypercomplex structure and the almost contact\n3-structure. The considered metric on the 2n-dimensional case is the Norden\nmetric, and the metrics in the other three cases are generated by it. The\npurpose of the dissertation is to carry out the following: 1. Further\ninvestigations of almost complex manifolds with Norden metric including\nstudying of natural connections with conditions for their torsion and invariant\ntensors under the twin interchange of Norden metrics. 2. Further investigations\nof almost contact manifolds with B-metric including studying of natural\nconnections with conditions for their torsion and associated Schouten-van\nKampen connections as well as a classification of affine connections. 3.\nIntroducing and studying of Sasaki-like almost contact complex Riemannian\nmanifolds. 4. Further investigations of almost hypercomplex manifolds with\nHermitian-Norden metrics including studying of integrable structures of the\nconsidered type on 4-dimensional Lie algebra and tangent bundles with the\ncomplete lift of the base metric; introducing of associated Nijenhuis tensors\nin relation with natural connections having totally skew-symmetric torsion as\nwell as quaternionic Kähler manifolds with Hermitian-Norden metrics. 5.\nIntroducing and studying of manifolds with almost contact 3-structures and\nmetrics of Hermitian-Norden type and, in particular, associated Nijenhuis\ntensors and their relationship with natural connections having totally\nskew-symmetric torsion.\n",
"title": "On Geometry of Manifolds with Some Tensor Structures and Metrics of Norden Type"
}
| null | null | null | null | true | null |
12754
| null |
Default
| null | null |
null |
{
"abstract": " Literature mentions only incidentally a sub-Doppler contribution in the\nexcitation spectrum of the backward fluorescence of a dense vapor. This\ncontribution is here investigated on Cs vapor, both on the first resonance line\n(894 nm) and on the weaker second resonance line (459 nm). We show that in a\nstrongly absorbing medium, the quenching of excited atoms moving towards a\nwindow irradiated under near normal incidence reduces the fluorescence on the\nred side of the excitation spectrum. Atoms moving slowly towards the window\nproduce a sub- Doppler velocity-selective contribution, whose visibility is\nhere improved by applying a frequency-modulation technique. This sub-Doppler\nfeature, induced by a surface quenching combined with a short absorption length\nfor the incident irradiation, exhibits close analogies with the narrow spectra\nappearing with thin vapor cells. We also show that a normal incidence\nirradiation is essential for the sub-Doppler feature to be observed, while it\nshould be independent of the detection geometry\n",
"title": "Backward-emitted sub-Doppler fluorescence from an optically thick atomic vapor"
}
| null | null | null | null | true | null |
12755
| null |
Default
| null | null |
null |
{
"abstract": " Recent high angular resolution observations of protoplanetary disks at\ndifferent wavelengths have revealed several kinds of structures, including\nmultiple bright and dark rings. Embedded planets are the most used explanation\nfor such structures, but there are alternative models capable of shaping the\ndust in rings as it has been observed. We assume a disk around a Herbig star\nand investigate the effect that ice lines have on the dust evolution, following\nthe growth, fragmentation, and dynamics of multiple dust size particles,\ncovering from 1 $\\mu$m to 2 m sized objects. We use simplified prescriptions of\nthe fragmentation velocity threshold, which is assumed to change radially at\nthe location of one, two, or three ice lines. We assume changes at the radial\nlocation of main volatiles, specifically H$_2$O, CO$_2$, and NH$_3$. Radiative\ntransfer calculations are done using the resulting dust density distributions\nin order to compare with current multiwavelength observations. We find that the\nstructures in the dust density profiles and radial intensities at different\nwavelengths strongly depend on the disk viscosity. A clear gap of emission can\nbe formed between ice lines and be surrounded by ring-like structures, in\nparticular between the H$_2$O and CO$_2$ (or CO). The gaps are expected to be\nshallower and narrower at millimeter emission than at near-infrared, opposite\nto model predictions of particle trapping. In our models, the total gas surface\ndensity is not expected to show strong variations, in contrast to other\ngap-forming scenarios such as embedded giant planets or radial variations of\nthe disk viscosity.\n",
"title": "Dust Density Distribution and Imaging Analysis of Different Ice Lines in Protoplanetary Disks"
}
| null | null | null | null | true | null |
12756
| null |
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| null | null |
null |
{
"abstract": " We present a clustering comparison of 12 galaxy formation models (including\nSemi-Analytic Models (SAMs) and Halo Occupation Distribution (HOD) models) all\nrun on halo catalogues and merger trees extracted from a single {\\Lambda}CDM\nN-body simulation. We compare the results of the measurements of the mean halo\noccupation numbers, the radial distribution of galaxies in haloes and the\n2-Point Correlation Functions (2PCF). We also study the implications of the\ndifferent treatments of orphan (galaxies not assigned to any dark matter\nsubhalo) and non-orphan galaxies in these measurements. Our main result is that\nthe galaxy formation models generally agree in their clustering predictions but\nthey disagree significantly between HOD and SAMs for the orphan satellites.\nAlthough there is a very good agreement between the models on the 2PCF of\ncentral galaxies, the scatter between the models when orphan satellites are\nincluded can be larger than a factor of 2 for scales smaller than 1 Mpc/h. We\nalso show that galaxy formation models that do not include orphan satellite\ngalaxies have a significantly lower 2PCF on small scales, consistent with\nprevious studies. Finally, we show that the 2PCF of orphan satellites is\nremarkably different between SAMs and HOD models. Orphan satellites in SAMs\npresent a higher clustering than in HOD models because they tend to occupy more\nmassive haloes. We conclude that orphan satellites have an important role on\ngalaxy clustering and they are the main cause of the differences in the\nclustering between HOD models and SAMs.\n",
"title": "nIFTy Cosmology: the clustering consistency of galaxy formation models"
}
| null | null | null | null | true | null |
12757
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| null | null |
null |
{
"abstract": " Consider the supercritical branching random walk on the real line in the\nboundary case and the associated Gibbs measure $\\nu_{n,\\beta}$ on the\n$n^\\text{th}$ generation, which is also the polymer measure on a disordered\ntree with inverse temperature $\\beta$. The convergence of the partition\nfunction $W_{n,\\beta}$, after rescaling, towards a nontrivial limit has been\nproved by A\\\"{\\i}dékon and Shi in the critical case $\\beta = 1$ and by\nMadaule when $\\beta >1$. We study here the near-critical case, where $\\beta_n\n\\to 1$, and prove the convergence of $W_{n,\\beta_n}$, after rescaling, towards\na constant multiple of the limit of the derivative martingale. Moreover,\ntrajectories of particles chosen according to the Gibbs measure $\\nu_{n,\\beta}$\nhave been studied by Madaule in the critical case, with convergence towards the\nBrownian meander, and by Chen, Madaule and Mallein in the strong disorder\nregime, with convergence towards the normalized Brownian excursion. We prove\nhere the convergence for trajectories of particles chosen according to the\nnear-critical Gibbs measure and display continuous families of processes from\nthe meander to the excursion or to the Brownian motion.\n",
"title": "The near-critical Gibbs measure of the branching random walk"
}
| null | null | null | null | true | null |
12758
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| null | null |
null |
{
"abstract": " The aim of this paper is to study relations between regular reductive PVs\nwith one-dimensional scalar multiplication and the structure of graded Lie\nalgebras. We will show that the regularity of such PVs is described by an\n$\\mathfrak{sl}_2$-triplet of a graded Lie algebra.\n",
"title": "Graded Lie algebras and regular prehomogeneous vector spaces with one-dimensional scalar multiplication"
}
| null | null | null | null | true | null |
12759
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null |
{
"abstract": " The star EPIC 210894022 has been identified from a light curve acquired\nthrough the K2 space mission as possibly orbited by a transiting planet. Our\naim is to confirm the planetary nature of the object and derive its fundamental\nparameters. We combine the K2 photometry with reconnaissance spectroscopy and\nradial velocity (RV) measurements obtained using three separate telescope and\nspectrograph combinations. The spectroscopic synthesis package SME has been\nused to derive the stellar photospheric parameters that were used as input to\nvarious stellar evolutionary tracks in order to derive the parameters of the\nsystem. The planetary transit was also validated to occur on the assumed host\nstar through adaptive imaging and statistical analysis. The star is found to be\nlocated in the background of the Hyades cluster at a distance at least 4 times\nfurther away from Earth than the cluster itself. The spectrum and the space\nvelocities of EPIC 210894022 strongly suggest it to be a member of the thick\ndisk population. We find that the star is a metal poor ([Fe/H]=-0.53+/-0.05\ndex) and alpha-rich somewhat evolved solar-like object of spectral type G3 with\nTeff=5730+/-50 K, logg=4.15+/-0.1 (cgs), radius of 1.3+/-0.1 R_Sun, and mass of\n0.88+/-0.02 M_Sun. The RV detection together with the imaging confirms with a\nhigh level of significance that the transit signature is caused by a\nsuper-Earth orbiting the star EPIC 210894022. We measure a mass of 8.6+/-3.9\nM_Earth and a radius of 1.9+/-0.2 R_Earth. A second more massive object with a\nperiod longer than about 120 days is indicated by a long term linear\nacceleration. With an age of > 10 Gyrs this system is one of the oldest where\nplanets is hitherto detected. Further studies of this planetary system is\nimportant since it contains information about the planetary formation process\nduring a very early epoch of the history of our Galaxy.\n",
"title": "EPIC 210894022b - A short period super-Earth transiting a metal poor, evolved old star"
}
| null | null | null | null | true | null |
12760
| null |
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| null | null |
null |
{
"abstract": " In our recent publication we have proposed a new methodology for\ndetermination of the two-term Machin-like formula for pi with small arguments\nof the arctangent function of kind $$ \\frac{\\pi }{4} = {2^{k - 1}}\\arctan\n\\left( {\\frac{1}{\\beta_1}} \\right) + \\arctan \\left( {\\frac{1}{\\beta_2}}\n\\right), $$ where $k$ and ${\\beta_1}$ are some integers and ${\\beta_2}$ is a\nrational number, dependent upon ${\\beta_1}$ and $k$. Although\n${1/\\left|\\beta_2\\right|}$ may be significantly smaller than ${1/\\beta_1}$, the\nlarge numbers in the numerator and denominator of $\\beta_2$ decelerate the\ncomputation. In this work we show how this problem can be effectively resolved\nby the Newton--Raphson iteration method.\n",
"title": "Efficient computation of pi by the Newton - Raphson iteration and a two-term Machin-like formula"
}
| null | null | null | null | true | null |
12761
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| null | null |
null |
{
"abstract": " Entanglement is central to our understanding of many-body quantum matter. In\nparticular, the entanglement spectrum, as eigenvalues of the reduced density\nmatrix of a subsystem, provides a unique footprint of properties of strongly\ncorrelated quantum matter from detection of topological order to\ncharacterisation of quantum critical systems. However, direct experimental\nmeasurement of the entanglement spectrum has so far remained elusive due to\nlack of direct experimental probes. Here we show that the entanglement spectrum\nof the ground state of a broad class of Hamiltonians becomes directly\naccessible as quantum simulation and spectroscopy of an entanglement Hamil-\ntonian, building on the Bisognano-Wichmann (BW) theorem of axiomatic quantum\nfield theory. Remarkably, this theorem gives an explicit physical construction\nof the entanglement Hamiltonian, identified as Hamiltonian of the many-body\nsystem of interest with spatially varying couplings. Building on this, we\npropose an immediate, scalable recipe for implementation of the entanglement\nHamiltonian, and measurement of the corresponding entanglement spectrum as\nspectroscopy of the Bisognano-Wichmann Hamiltonian with synthetic quantum\nsystems, including atoms in optical lat- tices and trapped ions. We illustrate\nand benchmark this scenario on a variety of models, spanning phenomena as\ndiverse as conformal field theories, topological order, and quantum phase\ntransitions.\n",
"title": "Quantum Simulation and Spectroscopy of Entanglement Hamiltonians"
}
| null | null | null | null | true | null |
12762
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{
"abstract": " We introduce a persistence-like pseudo-distance on Tamarkin's category and\nprove that the distance between an object and its Hamiltonian deformation is at\nmost the Hofer norm of the Hamiltonian function. Using the distance, we show a\nquantitative version of Tamarkin's non-displaceability theorem, which gives a\nlower bound of the displacement energy of compact subsets in a cotangent\nbundle.\n",
"title": "Persistence-like distance on Tamarkin's category and symplectic displacement energy"
}
| null | null | null | null | true | null |
12763
| null |
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| null | null |
null |
{
"abstract": " We continue the first and second authors' study of $q$-commutative power\nseries rings $R=k_q[[x_1,\\ldots,x_n]]$ and Laurent series rings $L=k_q[[x^{\\pm\n1}_1,\\ldots,x^{\\pm 1}_n]]$, specializing to the case in which the commutation\nparameters $q_{ij}$ are all roots of unity. In this setting, $R$ is a PI\nalgebra, and we can apply results of De Concini, Kac, and Procesi to show that\n$L$ is an Azumaya algebra whose degree can be inferred from the $q_{ij}$. Our\nmain result establishes an exact criterion (dependent on the $q_{ij}$) for\ndetermining when the centers of $L$ and $R$ are commutative Laurent series and\ncommutative power series rings, respectively. In the event this criterion is\nsatisfied, it follows that $L$ is a unique factorization ring in the sense of\nChatters and Jordan, and it further follows, by results of Dumas, Launois,\nLenagan, and Rigal, that $R$ is a unique factorization ring. We thus produce\nnew examples of complete, local, noetherian, noncommutative, unique\nfactorization rings (that are PI domains).\n",
"title": "On $q$-commutative power and Laurent series rings at roots of unity"
}
| null | null | null | null | true | null |
12764
| null |
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| null | null |
null |
{
"abstract": " We consider a piecewise deterministic Markov decision process, where the\nexpected exponential utility of total (nonnegative) cost is to be minimized.\nThe cost rate, transition rate and post-jump distributions are under control.\nThe state space is Borel, and the transition and cost rates are locally\nintegrable along the drift. Under natural conditions, we establish the\noptimality equation, justify the value iteration algorithm, and show the\nexistence of a deterministic stationary optimal policy. Applied to special\ncases, the obtained results already significantly improve some existing results\nin the literature on finite horizon and infinite horizon discounted\nrisk-sensitive continuous-time Markov decision processes.\n",
"title": "On risk-sensitive piecewise deterministic Markov decision processes"
}
| null | null | null | null | true | null |
12765
| null |
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| null | null |
null |
{
"abstract": " Multiplex networks offer an important tool for the study of complex systems\nand extending techniques originally designed for single--layer networks is an\nimportant area of study. One of the most important methods for analyzing\nnetworks is clustering the nodes into communities that represent common\nconnectivity patterns. In this paper we extend spectral clustering to multiplex\nstructures and discuss some of the difficulties that arise in attempting to\ndefine a natural generalization. In order to analyze our approach, we describe\nthree simple, synthetic multiplex networks and compare the performance of\ndifferent multiplex models. Our results suggest that a dynamically motivated\nmodel is more successful than a structurally motivated model in discovering the\nappropriate communities.\n",
"title": "Spectral Clustering Methods for Multiplex Networks"
}
| null | null | null | null | true | null |
12766
| null |
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| null | null |
null |
{
"abstract": " We establish zero-one laws and convergence laws for monadic second-order\nlogic (MSO) (and, a fortiori, first-order logic) on a number of interesting\ngraph classes. In particular, we show that MSO obeys a zero-one law on the\nclass of connected planar graphs, the class of connected graphs of tree-width\nat most k and the class of connected graphs excluding the k-clique as a minor.\nIn each of these cases, dropping the connectivity requirement leads to a class\nwhere the zero-one law fails but a convergence law for MSO still holds.\n",
"title": "Logical properties of random graphs from small addable classes"
}
| null | null |
[
"Computer Science",
"Mathematics"
] | null | true | null |
12767
| null |
Validated
| null | null |
null |
{
"abstract": " We introduce here the concept of establishing Parity-time symmetry through a\ngauge transformation involving a shift of the mirror plane for the Parity\noperation. The corresponding unitary transformation on the system's\nconstitutive matrix allows us to generate and explore a family of equivalent\nParity-time symmetric systems. We further derive that unidirectional zero\nreflection can always be associated with a gauged PT-symmetry and demonstrate\nthis experimentally using a microstrip transmission-line with magnetoelectric\ncoupling. This study allows us to use bianisotropy as a simple route to realize\nand explore exceptional point behaviour of PT-symmetric or generally\nnon-Hermitian systems.\n",
"title": "Unidirectional zero reflection as gauged parity-time symmetry"
}
| null | null | null | null | true | null |
12768
| null |
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| null | null |
null |
{
"abstract": " Formation of membrane necks is crucial for fission and fusion in lipid\nbilayers. In this work, we seek to answer the following fundamental question:\nwhat is the relationship between protein-induced spontaneous mean curvature and\nthe Gaussian curvature at a membrane neck? Using an augmented Helfrich model\nfor lipid bilayers to include membrane-protein interaction, we solve the shape\nequation on catenoids to find the field of spontaneous curvature that satisfies\nmechanical equilibrium of membrane necks. In this case, the shape equation\nreduces to a variable coefficient Helmholtz equation for spontaneous curvature,\nwhere the source term is proportional to the Gaussian curvature. We show how\nthis latter quantity is responsible for non-uniform distribution of spontaneous\ncurvature in minimal surfaces. We then explore the energetics of catenoids with\ndifferent spontaneous curvature boundary conditions and geometric asymmetries\nto show how heterogeneities in spontaneous curvature distribution can couple\nwith Gaussian curvature to result in membrane necks of different geometries.\n",
"title": "Gaussian curvature directs the distribution of spontaneous curvature on bilayer membrane necks"
}
| null | null | null | null | true | null |
12769
| null |
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| null | null |
null |
{
"abstract": " Information theory is a mathematical theory of learning with deep connections\nwith topics as diverse as artificial intelligence, statistical physics, and\nbiological evolution. Many primers on the topic paint a broad picture with\nrelatively little mathematical sophistication, while many others develop\nspecific application areas in detail. In contrast, these informal notes aim to\noutline some elements of the information-theoretic \"way of thinking,\" by\ncutting a rapid and interesting path through some of the theory's foundational\nconcepts and theorems. We take the Kullback-Leibler divergence as our\nfoundational concept, and then proceed to develop the entropy and mutual\ninformation. We discuss some of the main foundational results, including the\nChernoff bounds as a characterization of the divergence; Gibbs' Theorem; and\nthe Data Processing Inequality. A recurring theme is that the definitions of\ninformation theory support natural theorems that sound \"obvious\" when\ntranslated into English. More pithily, \"information theory makes common sense\nprecise.\" Since the focus of the notes is not primarily on technical details,\nproofs are provided only where the relevant techniques are illustrative of\nbroader themes. Otherwise, proofs and intriguing tangents are referenced in\nliberally-sprinkled footnotes. The notes close with a highly nonexhaustive list\nof references to resources and other perspectives on the field.\n",
"title": "Divergence, Entropy, Information: An Opinionated Introduction to Information Theory"
}
| null | null |
[
"Mathematics",
"Statistics"
] | null | true | null |
12770
| null |
Validated
| null | null |
null |
{
"abstract": " Stochastic Constraint Programming (SCP) is an extension of Constraint\nProgramming (CP) used for modelling and solving problems involving constraints\nand uncertainty. SCP inherits excellent modelling abilities and filtering\nalgorithms from CP, but so far it has not been applied to large problems.\nReinforcement Learning (RL) extends Dynamic Programming to large stochastic\nproblems, but is problem-specific and has no generic solvers. We propose a\nhybrid combining the scalability of RL with the modelling and constraint\nfiltering methods of CP. We implement a prototype in a CP system and\ndemonstrate its usefulness on SCP problems.\n",
"title": "Stochastic Constraint Programming as Reinforcement Learning"
}
| null | null | null | null | true | null |
12771
| null |
Default
| null | null |
null |
{
"abstract": " Kernel adaptive filters, a class of adaptive nonlinear time-series models,\nare known by their ability to learn expressive autoregressive patterns from\nsequential data. However, for trivial monotonic signals, they struggle to\nperform accurate predictions and at the same time keep computational complexity\nwithin desired boundaries. This is because new observations are incorporated to\nthe dictionary when they are far from what the algorithm has seen in the past.\nWe propose a novel approach to kernel adaptive filtering that compares new\nobservations against dictionary samples in terms of their unit-norm\n(normalised) versions, meaning that new observations that look like previous\nsamples but have a different magnitude are not added to the dictionary. We\nachieve this by proposing the unit-norm Gaussian kernel and define a\nsparsification criterion for this novel kernel. This new methodology is\nvalidated on two real-world datasets against standard KAF in terms of the\nnormalised mean square error and the dictionary size.\n",
"title": "Improving Sparsity in Kernel Adaptive Filters Using a Unit-Norm Dictionary"
}
| null | null | null | null | true | null |
12772
| null |
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| null | null |
null |
{
"abstract": " We provide a self-contained formulation of the BPHZ theorem in the Euclidean\ncontext, which yields a systematic procedure to \"renormalise\" otherwise\ndivergent integrals appearing in generalised convolutions of functions with a\nsingularity of prescribed order at their origin. We hope that the formulation\ngiven in this article will appeal to an analytically minded audience and that\nit will help to clarify to what extent such renormalisations are arbitrary (or\nnot). In particular, we do not assume any background whatsoever in quantum\nfield theory and we stay away from any discussion of the physical context in\nwhich such problems typically arise.\n",
"title": "An analyst's take on the BPHZ theorem"
}
| null | null | null | null | true | null |
12773
| null |
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| null | null |
null |
{
"abstract": " Necessary conditions for existence of normal extremals in optimal control of\nsystems subject to nonholonomic constraints are derived as solutions of a\nconstrained second order variational problems. In this work, a geometric\ninterpretation of the derivation is studied from the theory of Lie algebroids.\nWe employ such a framework to describe the problem into a unifying formalism\nfor normal extremals in optimal control of nonholonomic systems and including\nsituations that have not been considered before in the literature from this\nperspective. We show that necessary conditions for existence of extremals in\nthe optimal control problem can be also determined by a Hamiltonian system on\nthe cotangent bundle of a skew-symmetric algebroid.\n",
"title": "A variational-geometric approach for the optimal control of nonholonomic systems"
}
| null | null | null | null | true | null |
12774
| null |
Default
| null | null |
null |
{
"abstract": " A beam imaging detector was developed by coupling a multi-strip anode with\ndelay line readout to an E$\\times$B microchannel plate (MCP) detector. This\ndetector is capable of measuring the incident position of the beam particles in\none-dimension. To assess the spatial resolution, the detector was illuminated\nby an $\\alpha$-source with an intervening mask that consists of a series of\nprecisely-machined slits. The measured spatial resolution was 520$\\mu$m FWHM,\nwhich was improved to 413$\\mu$m FWHM by performing an FFT of the signals,\nrejecting spurious signals on the delay line, and requiring a minimum signal\namplitude. This measured spatial resolution of 413$\\mu$m FWHM corresponds to an\nintrinsic resolution of 334$\\mu$m FWHM when the effect of the finite slit width\nis de-convoluted. To understand the measured resolution, the performance of the\ndetector is simulated with the ion-trajectory code SIMION.\n",
"title": "Development of a compact ExB microchannel plate detector for beam imaging"
}
| null | null | null | null | true | null |
12775
| null |
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| null | null |
null |
{
"abstract": " A widely studied non-deterministic polynomial time (NP) hard problem lies in\nfinding a route between the two nodes of a graph. Often meta-heuristics\nalgorithms such as $A^{*}$ are employed on graphs with a large number of nodes.\nHere, we propose a deep recurrent neural network architecture based on the\nSequence-2-Sequence (Seq2Seq) model, widely used, for instance in text\ntranslation. Particularly, we illustrate that utilising a context vector that\nhas been learned from two different recurrent networks enables increased\naccuracies in learning the shortest route of a graph. Additionally, we show\nthat one can boost the performance of the Seq2Seq network by smoothing the loss\nfunction using a homotopy continuation of the decoder's loss function.\n",
"title": "StackSeq2Seq: Dual Encoder Seq2Seq Recurrent Networks"
}
| null | null | null | null | true | null |
12776
| null |
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| null | null |
null |
{
"abstract": " Recently, hashing methods have been widely used in large-scale image\nretrieval. However, most existing hashing methods did not consider the\nhierarchical relation of labels, which means that they ignored the rich\ninformation stored in the hierarchy. Moreover, most of previous works treat\neach bit in a hash code equally, which does not meet the scenario of\nhierarchical labeled data. In this paper, we propose a novel deep hashing\nmethod, called supervised hierarchical deep hashing (SHDH), to perform hash\ncode learning for hierarchical labeled data. Specifically, we define a novel\nsimilarity formula for hierarchical labeled data by weighting each layer, and\ndesign a deep convolutional neural network to obtain a hash code for each data\npoint. Extensive experiments on several real-world public datasets show that\nthe proposed method outperforms the state-of-the-art baselines in the image\nretrieval task.\n",
"title": "Supervised Deep Hashing for Hierarchical Labeled Data"
}
| null | null |
[
"Computer Science"
] | null | true | null |
12777
| null |
Validated
| null | null |
null |
{
"abstract": " We give sufficient conditions for when groups generated by automata in a\nclass $\\mathcal{C}$ of transducers, which contains the class of reset automata\ntransducers, have infinite order. As a consequence we also demonstrate that if\na group generated by an automata in $\\mathcal{C}$ is infinite, then it contains\na free semigroup of rank at least 2. This gives a new proof, in the context of\ngroups generated by automaton in $\\mathcal{C}$, of a result of Chou showing\nthat finitely generated elementary amenable groups either have polynomial\ngrowth or contain a free semigroup of rank at least 2.\nWe also study what we call the `core growth rate' of elements of\n$\\mathcal{C}$. This turns out to be equivalent to the growth rate of certain\ninitial transducers. We give examples of transducers with exponential core\ngrowth rate, and conjecture that all infinite order transducers in the class\n$\\mathcal{C}$ have exponential core growth rate.\n",
"title": "The growth rates of automaton groups generated by reset automata"
}
| null | null | null | null | true | null |
12778
| null |
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| null | null |
null |
{
"abstract": " We present in this article a family of new combinatorial identities via\npurely differential/complex geometry methods, which include as a speical case a\nunified and explicit formula for Chern numbers of all complex flag manifolds.\nOur strategy is to construct concrete circle actions with isolated fixed points\non these manifolds and explicitly determine their weights. Then applying Bott's\nresidue formula to these models yields the desired results.\n",
"title": "Combinatorial identities and Chern numbers of complex flag manifolds"
}
| null | null | null | null | true | null |
12779
| null |
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| null | null |
null |
{
"abstract": " Chondrules are the dominant bulk silicate constituent of chondritic\nmeteorites and originate from highly energetic, local processes during the\nfirst million years after the birth of the Sun. So far, an astrophysically\nconsistent chondrule formation scenario, explaining major chemical, isotopic\nand textural features, remains elusive. Here, we examine the prospect of\nforming chondrules from planetesimal collisions. We show that intensely melted\nbodies with interior magma oceans became rapidly chemically equilibrated and\nphysically differentiated. Therefore, collisional interactions among such\nbodies would have resulted in chondrule-like but basaltic spherules, which are\nnot observed in the meteoritic record. This inconsistency with the expected\ndynamical interactions hints at an incomplete understanding of the planetary\ngrowth regime during the protoplanetary disk phase. To resolve this conundrum,\nwe examine how the observed chemical and isotopic features of chondrules\nconstrain the dynamical environment of accreting chondrite parent bodies by\ninterpreting the meteoritic record as an impact-generated proxy of\nplanetesimals that underwent repeated collision and reaccretion cycles. Using a\ncoupled evolution-collision model we demonstrate that the vast majority of\ncollisional debris feeding the asteroid main belt must be derived from\nplanetesimals which were partially molten at maximum. Therefore, the precursors\nof chondrite parent bodies either formed primarily small, from sub-canonical\naluminum-26 reservoirs, or collisional destruction mechanisms were efficient\nenough to shatter planetesimals before they reached the magma ocean phase.\nFinally, we outline the window in parameter space for which chondrule formation\nfrom planetesimal collisions can be reconciled with the meteoritic record and\nhow our results can be used to further constrain early solar system dynamics.\n",
"title": "Impact splash chondrule formation during planetesimal recycling"
}
| null | null | null | null | true | null |
12780
| null |
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| null | null |
null |
{
"abstract": " Because of vast volume of data being produced by today's scientific\nsimulations and experiments, lossy data compressor allowing user-controlled\nloss of accuracy during the compression is a relevant solution for\nsignificantly reducing the data size. However, lossy compressor developers and\nusers are missing a tool to explore the features of scientific datasets and\nunderstand the data alteration after compression in a systematic and reliable\nway. To address this gap, we have designed and implemented a generic framework\ncalled Z-checker. On the one hand, Z-checker combines a battery of data\nanalysis components for data compression. On the other hand, Z-checker is\nimplemented as an open-source community tool to which users and developers can\ncontribute and add new analysis components based on their additional analysis\ndemands. In this paper, we present a survey of existing lossy compressors. Then\nwe describe the design framework of Z-checker, in which we integrated\nevaluation metrics proposed in prior work as well as other analysis tools.\nSpecifically, for lossy compressor developers, Z-checker can be used to\ncharacterize critical properties of any dataset to improve compression\nstrategies. For lossy compression users, Z-checker can detect the compression\nquality, provide various global distortion analysis comparing the original data\nwith the decompressed data and statistical analysis of the compression error.\nZ-checker can perform the analysis with either coarse granularity or fine\ngranularity, such that the users and developers can select the best-fit,\nadaptive compressors for different parts of the dataset. Z-checker features a\nvisualization interface displaying all analysis results in addition to some\nbasic views of the datasets such as time series. To the best of our knowledge,\nZ-checker is the first tool designed to assess lossy compression\ncomprehensively for scientific datasets.\n",
"title": "Z-checker: A Framework for Assessing Lossy Compression of Scientific Data"
}
| null | null | null | null | true | null |
12781
| null |
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| null | null |
null |
{
"abstract": " We suggest an efficient method to resolve electronic cusps in electronic\nstructure calculations by using an effective transcorrelated Hamiltonian. This\neffective Hamiltonian takes a simple form for plane wave bases, containing up\nto two-body operators only, and its use incurs almost no additional\ncomputational overhead compared to that of the original Hamiltonian. We apply\nthis method in combination with the full configuration interaction quantum\nMonte Carlo (FCIQMC) method to the homogeneous electron gas. As a projection\ntechnique, the non-Hermitian nature of the transcorrelated Hamiltonian does not\ncause complications or numerical difficulties for FCIQMC. The rate of\nconvergence of the total energy to the complete basis set limit is improved\nfrom ${\\cal O}(M^{-1})$ to ${\\cal O}\\left({M^{-5/3}}\\right)$, where $M$ is the\ntotal number of orbital basis functions.\n",
"title": "Combining the Transcorrelated method with Full Configuration Interaction Quantum Monte Carlo: application to the homogeneous electron gas"
}
| null | null | null | null | true | null |
12782
| null |
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| null | null |
null |
{
"abstract": " We characterize the information dynamics of strongly disordered systems using\na combination of analytics, exact diagonalization, and matrix product operator\nsimulations. More specifically, we study the spreading of quantum information\nin three different scenarios: thermalizing, Anderson localized, and many-body\nlocalized. We qualitatively distinguish these cases by quantifying the amount\nof remnant information in a local region. The nature of the dynamics is further\nexplored by computing the propagation of mutual information with respect to\nvarying partitions. Finally, we demonstrate that classical simulability, as\ncaptured by the magnitude of MPO truncation errors, exhibits enhanced\nfluctuations near the localization transition, suggesting the possibility of\nits use as a diagnostic of the critical point.\n",
"title": "Dynamics of quantum information in many-body localized systems"
}
| null | null | null | null | true | null |
12783
| null |
Default
| null | null |
null |
{
"abstract": " We study theoretically the velocity cross-correlations of a viscous fluid\nconfined in a slit between two viscoelastic media. We analyze the effect of\nthese correlations on the motions of particles suspended in the fluid. The\ncompliance of the confining boundaries gives rise to a long-ranged pair\ncorrelation, decaying only as $1/r$ with the interparticle distance $r$. We\nshow how this long-ranged effect may be used to extract the viscoelastic\nproperties of the confining media without embedding tracer particles in them.\nWe discuss the remarkable robustness of such a potential technique with respect\nto details of the confinement, and its expected statistical advantages over\nstandard two-point microrheology.\n",
"title": "Correlations in suspensions confined between viscoelastic surfaces: Noncontact microrheology"
}
| null | null | null | null | true | null |
12784
| null |
Default
| null | null |
null |
{
"abstract": " The network of filaments with embedded clusters surrounding voids seen in\nmaps derived from redshift surveys and reproduced in simulations has been\nreferred to as the cosmic web. A complementary description is provided by\nconsidering the shear in the velocity field of galaxies. The eigenvalues of the\nshear provide information on whether a region is collapsing in three\ndimensions, the condition for a knot, expanding in three-dimensions, the\ncondition for a void, or in the intermediate condition of a filament or sheet.\nThe structures that are quantitatively defined by the eigenvalues can be\napproximated by iso-contours that provide a visual representation of the cosmic\nvelocity (V) web. The current application is based on radial peculiar\nvelocities from the Cosmicflows-2 collection of distances. The\nthree-dimensional velocity field is constructed using the Wiener filter\nmethodology in the linear approximation. Eigenvalues of the velocity shear are\ncalculated at each point on a grid. Here, knots and filaments are visualized\nacross a local domain of diameter ~0.1c.\n",
"title": "The Cosmic V-Web"
}
| null | null | null | null | true | null |
12785
| null |
Default
| null | null |
null |
{
"abstract": " Constructing $r$-th nonresidue over a finite field is a fundamental\ncomputational problem. A related problem is to construct an irreducible\npolynomial of degree $r^e$ (where $r$ is a prime) over a given finite field\n$\\mathbb{F}_q$ of characteristic $p$ (equivalently, constructing the bigger\nfield $\\mathbb{F}_{q^{r^e}}$). Both these problems have famous randomized\nalgorithms but the derandomization is an open question. We give some new\nconnections between these two problems and their variants.\nIn 1897, Stickelberger proved that if a polynomial has an odd number of even\ndegree factors, then its discriminant is a quadratic nonresidue in the field.\nWe give an extension of Stickelberger's Lemma; we construct $r$-th nonresidues\nfrom a polynomial $f$ for which there is a $d$, such that, $r|d$ and\n$r\\nmid\\,$#(irreducible factor of $f(x)$ of degree $d$). Our theorem has the\nfollowing interesting consequences: (1) we can construct $\\mathbb{F}_{q^m}$ in\ndeterministic poly(deg($f$),$m\\log q$)-time if $m$ is an $r$-power and $f$ is\nknown; (2) we can find $r$-th roots in $\\mathbb{F}_{p^m}$ in deterministic\npoly($m\\log p$)-time if $r$ is constant and $r|\\gcd(m,p-1)$.\nWe also discuss a conjecture significantly weaker than the Generalized\nRiemann hypothesis to get a deterministic poly-time algorithm for $r$-th root\nfinding.\n",
"title": "Irreducibility and r-th root finding over finite fields"
}
| null | null | null | null | true | null |
12786
| null |
Default
| null | null |
null |
{
"abstract": " With decreasing temperature Sr$_2$VO$_4$ undergoes two structural phase\ntransitions, tetragonal-to-orthorhombic-to-tetragonal, without long-range\nmagnetic order. Recent experiments suggest, that only at very low temperature\nSr$_{2}$VO$_{4}$ might enter some, yet unknown, phase with long-range magnetic\norder, but without orthorhombic distortion. By combining relativistic density\nfunctional theory with an extended spin-1/2 compass-Heisenberg model we find an\nantiferromagnetic single-stripe ground state with highly competing exchange\ninteractions, involving a non negligible inter-layer coupling, which places the\nsystem at the crossover between between the XY and Heisenberg picture. Most\nstrikingly, we find a strong two-site \"spin-compass\" exchange anisotropy which\nis relieved by the orthorhombic distortion induced by the spin stripe order.\nBased on these results we discuss the origin of the hidden order phase and the\npossible formation of a spin-liquid at low temperatures.\n",
"title": "Competing magnetic interactions in spin-1/2 square lattice: hidden order in Sr$_2$VO$_4$"
}
| null | null | null | null | true | null |
12787
| null |
Default
| null | null |
null |
{
"abstract": " A matching in a two-sided market often incurs an externality: a matched\nresource may become unavailable to the other side of the market, at least for a\nwhile. This is especially an issue in online platforms involving human experts\nas the expert resources are often scarce. The efficient utilization of experts\nin these platforms is made challenging by the fact that the information\navailable about the parties involved is usually limited.\nTo address this challenge, we develop a model of a task-expert matching\nsystem where a task is matched to an expert using not only the prior\ninformation about the task but also the feedback obtained from the past\nmatches. In our model the tasks arrive online while the experts are fixed and\nconstrained by a finite service capacity. For this model, we characterize the\nmaximum task resolution throughput a platform can achieve. We show that the\nnatural greedy approaches where each expert is assigned a task most suitable to\nher skill is suboptimal, as it does not internalize the above externality. We\ndevelop a throughput optimal backpressure algorithm which does so by accounting\nfor the `congestion' among different task types. Finally, we validate our model\nand confirm our theoretical findings with data-driven simulations via logs of\nMath.StackExchange, a StackOverflow forum dedicated to mathematics.\n",
"title": "Adaptive Matching for Expert Systems with Uncertain Task Types"
}
| null | null |
[
"Computer Science",
"Statistics"
] | null | true | null |
12788
| null |
Validated
| null | null |
null |
{
"abstract": " We study the one dimensional t-t'-J model for generic couplings using two\ncomplementary theories, the extremely correlated Fermi liquid theory and\ntime-dependent density matrix renormalization group over a broad energy scale.\nThe two methods provide a unique insight into the strong momentum dependence of\nthe self-energy of this prototypical non-Fermi liquid, described at low\nenergies as a Tomonaga-Luttinger liquid. We also demonstrate its intimate\nrelationship to spin-charge separation, i.e. the splitting of Landau\nquasiparticles of higher dimensions into two constituents, driven by strong\nquantum fluctuations inherent in one dimension. The momentum distribution\nfunction, the spectral function, and the excitation dispersion of these two\nmethods also compare well.\n",
"title": "The t-t'-J model in one dimension using extremely correlated Fermi liquid theory and time dependent density matrix renormalization group"
}
| null | null |
[
"Physics"
] | null | true | null |
12789
| null |
Validated
| null | null |
null |
{
"abstract": " This paper proposes Concurrent-Access Obfuscated Store (CAOS), a construction\nfor remote data storage that provides access-pattern obfuscation in a\nhonest-but-curious adversarial model, while allowing for low bandwidth overhead\nand client storage. Compared to the state of the art, the main advantage of\nCAOS is that it supports concurrent access without a proxy, for multiple\nread-only clients and a single read-write client. Concurrent access is achieved\nby letting clients maintain independent maps that describe how the data is\nstored. These maps might diverge from client to client, but it is guaranteed\nthat no client will ever lose track of current data. We achieve efficiency and\nconcurrency at the expense of perfect obfuscation: in CAOS the extent to which\naccess patterns are hidden is determined by the resources allocated to its\nbuilt-in obfuscation mechanism. To assess this trade-off we provide both a\nsecurity and a performance analysis of our protocol instance. We additionally\nprovide a proof-of-concept implementation.\n",
"title": "CAOS: Concurrent-Access Obfuscated Store"
}
| null | null | null | null | true | null |
12790
| null |
Default
| null | null |
null |
{
"abstract": " Automated software verification of concurrent programs is challenging because\nof exponentially growing state spaces. Verification techniques such as model\nchecking need to explore a large number of possible executions that are\npossible under a non-deterministic scheduler. State space reduction techniques\nsuch as partial order reduction simplify the verification problem, however, the\nreduced state space may still be exponentially large and intractable.\nThis paper discusses Iteratively Relaxed Scheduling, a framework that uses\nscheduling constraints in order to simplify the verification problem and enable\nautomated verification of programs which could not be handled with fully\nnon-deterministic scheduling. Program executions are safe as long as the same\nscheduling constraints are enforced under which the program has been verified,\ne.g., by instrumenting a program with additional synchronization. As strict\nenforcement of scheduling constraints may induce a high execution time\noverhead, we present optimizations over a naive solution that reduce this\noverhead. Our evaluation of a prototype implementation on well-known benchmark\nprograms shows the effect of scheduling constraints on the execution time\noverhead and how this overhead can be reduced by relaxing and choosing\nconstraints.\n",
"title": "Safe Execution of Concurrent Programs by Enforcement of Scheduling Constraints"
}
| null | null | null | null | true | null |
12791
| null |
Default
| null | null |
null |
{
"abstract": " The short-term voltage stability (SVS) problem in large-scale receiving-end\npower systems is serious due to the increasing load demand, the increasing use\nof electronically controlled loads and so on. Some serious blackouts are\nconsidered to be related to short-term voltage instability. In China, the East\nChina Grid (ECG) is especially vulnerable to short-term voltage instability due\nthe its increasing dependence on power injection from external grids through\nHVDC links. However, the SVS criteria used in practice are all qualitative and\nthe SVS indices proposed in previous researches are mostly based on the\nqualitative SVS criteria. So a Short-Term Voltage Stability Index (SVSI), which\nis continuous, quantitative and multi-dimensional, is proposed in this paper.\nThe SVSI consists of three components, which reflects the transient voltage\nrestoration, the transient voltage oscillation and the steady-state recovery\nability of the voltage signal respectively after the contingency has been\ncleared. The theoretical backgrounds and affected factors of these three\ncomponents of SVSI are analyzed, together with some feasible applications. The\nverification of the validity of SVSI are tested through more 10,000 cases based\non ECG. Additionally, a simple case of selecting candidate locations to install\ndynamic var using SVSI is presented to show its feasibility to solve the\noptimization problem for dynamic var allocation.\n",
"title": "A Short-Term Voltage Stability Index and case studies"
}
| null | null | null | null | true | null |
12792
| null |
Default
| null | null |
null |
{
"abstract": " Macaulay's inverse system is an effective method to construct Artinian\nK-algebras with additional properties like, Gorenstein, level, more generally\nwith any socle type. Recently, Elias and Rossi gave the structure of the\ninverse system of $d$-dimensional Gorenstein K-algebras for any $d>0$. In this\npaper we extend their result by establishing a one-to-one correspondence\nbetween $d$-dimensional level K-algebras and certain submodules of the divided\npower ring. We give several examples to illustrate our result.\n",
"title": "The Structure of the Inverse System of Level $K$-Algebras"
}
| null | null | null | null | true | null |
12793
| null |
Default
| null | null |
null |
{
"abstract": " In many complex networked systems, such as online social networks, activity\noriginates at certain nodes and subsequently spreads on the network through\ninfluence. In this work, we consider the problem of modeling the spread of\ninfluence and the identification of influential entities in a complex network\nwhen nodal activation can happen via two different mechanisms. The first\nmechanism of activation stems from factors that are intrinsic to the node. The\nsecond mechanism comes from the influence of connected neighbors. After\nintroducing the model, we provide an algorithm to mine for the influential\nnodes in such a scenario by modifying the well-known influence maximization\nalgorithm to work with our model that incorporates both forms of activation.\nOur model can be considered as a variation of the independent cascade diffusion\nmodel. We provide small motivating examples to facilitate an intuitive\nunderstanding of the effect of including the intrinsic activation mechanism. We\nsketch a proof of the submodularity of the influence function under the new\nformulation and demonstrate the same on larger graphs. Based on the model, we\nexplain how influential content creators can drive engagement on social media\nplatforms. Using additional experiments on a Twitter dataset, we then show how\nthe formulation can be applied to real-world social media datasets. Finally, we\nderive a centrality metric that takes into account, both the mechanisms of\nactivation and provides for an accurate, computationally efficient, alternate\napproach to the problem of identifying influencers under intrinsic activation.\n",
"title": "Exploring the Role of Intrinsic Nodal Activation on the Spread of Influence in Complex Networks"
}
| null | null |
[
"Computer Science"
] | null | true | null |
12794
| null |
Validated
| null | null |
null |
{
"abstract": " We show that the border support rank of the tensor corresponding to\ntwo-by-two matrix multiplication is seven over the complex numbers. We do this\nby constructing two polynomials that vanish on all complex tensors with format\nfour-by-four-by-four and border rank at most six, but that do not vanish\nsimultaneously on any tensor with the same support as the two-by-two matrix\nmultiplication tensor. This extends the work of Hauenstein, Ikenmeyer, and\nLandsberg. We also give two proofs that the support rank of the two-by-two\nmatrix multiplication tensor is seven over any field: one proof using a result\nof De Groote saying that the decomposition of this tensor is unique up to\nsandwiching, and another proof via the substitution method. These results\nanswer a question asked by Cohn and Umans. Studying the border support rank of\nthe matrix multiplication tensor is relevant for the design of matrix\nmultiplication algorithms, because upper bounds on the border support rank of\nthe matrix multiplication tensor lead to upper bounds on the computational\ncomplexity of matrix multiplication, via a construction of Cohn and Umans.\nMoreover, support rank has applications in quantum communication complexity.\n",
"title": "The border support rank of two-by-two matrix multiplication is seven"
}
| null | null | null | null | true | null |
12795
| null |
Default
| null | null |
null |
{
"abstract": " Given a large graph, how can we determine similarity between nodes in a fast\nand accurate way? Random walk with restart (RWR) is a popular measure for this\npurpose and has been exploited in numerous data mining applications including\nranking, anomaly detection, link prediction, and community detection. However,\nprevious methods for computing exact RWR require prohibitive storage sizes and\ncomputational costs, and alternative methods which avoid such costs by\ncomputing approximate RWR have limited accuracy. In this paper, we propose TPA,\na fast, scalable, and highly accurate method for computing approximate RWR on\nlarge graphs. TPA exploits two important properties in RWR: 1) nodes close to a\nseed node are likely to be revisited in following steps due to block-wise\nstructure of many real-world graphs, and 2) RWR scores of nodes which reside\nfar from the seed node are proportional to their PageRank scores. Based on\nthese two properties, TPA divides approximate RWR problem into two subproblems\ncalled neighbor approximation and stranger approximation. In the neighbor\napproximation, TPA estimates RWR scores of nodes close to the seed based on\nscores of few early steps from the seed. In the stranger approximation, TPA\nestimates RWR scores for nodes far from the seed using their PageRank. The\nstranger and neighbor approximations are conducted in the preprocessing phase\nand the online phase, respectively. Through extensive experiments, we show that\nTPA requires up to 3.5x less time with up to 40x less memory space than other\nstate-of-the-art methods for the preprocessing phase. In the online phase, TPA\ncomputes approximate RWR up to 30x faster than existing methods while\nmaintaining high accuracy.\n",
"title": "TPA: Fast, Scalable, and Accurate Method for Approximate Random Walk with Restart on Billion Scale Graphs"
}
| null | null |
[
"Computer Science"
] | null | true | null |
12796
| null |
Validated
| null | null |
null |
{
"abstract": " Polystyrene-based phosphorene nanocomposites were prepared by a solvent\nblending procedure allowing the embedding of black phosphorus (BP) nanoflakes\nin the polymer matrix. Raman spectroscopy, X Ray Diffraction and TEM microscopy\nwere employed to characterize the structural and the morphological\ncharacteristics of the achieved hybrids, with the aim to evaluate the\ndispersion level of black phosphorus layers. TGA, DSC analysis as well as\nthermal oxidation and photo-degradation techniques were employed to investigate\nthe thermal- and the photo-stability of the samples. The collected results\nevidenced better thermal and photostability of both polymer matrix and\ndispersed layered phosphorus, suggesting really interesting polymer-nanofiller\nsynergic effects ascribable to the presence and the good dispersion of the\n2D-nanomaterial.\n",
"title": "Novel polystyrene-based nanocomposites by phosphorene dispersion"
}
| null | null | null | null | true | null |
12797
| null |
Default
| null | null |
null |
{
"abstract": " The main purpose of this paper is to provide a summary of the fundamental\nmethods for analyzing delay differential equations arising in biology and\nmedicine. These methods are employed to illustrate the effects of time delay on\nthe behavior of solutions, which include destabilization of steady states,\nperiodic and oscillatory solutions, bifurcations, and stability switches. The\nbiological interpretations of delay effects are briefly discussed.\n",
"title": "Analysis and Applications of Delay Differential Equations in Biology and Medicine"
}
| null | null | null | null | true | null |
12798
| null |
Default
| null | null |
null |
{
"abstract": " A fixed-mobile bigraph G is a bipartite graph such that the vertices of one\npartition set are given with fixed positions in the plane and the mobile\nvertices of the other part, together with the edges, must be added to the\ndrawing. We assume that G is planar and study the problem of finding, for a\ngiven k >= 0, a planar poly-line drawing of G with at most k bends per edge. In\nthe most general case, we show NP-hardness. For k=0 and under additional\nconstraints on the positions of the fixed or mobile vertices, we either prove\nthat the problem is polynomial-time solvable or prove that it belongs to NP.\nFinally, we present a polynomial-time testing algorithm for a certain type of\n\"layered\" 1-bend drawings.\n",
"title": "Planar Drawings of Fixed-Mobile Bigraphs"
}
| null | null |
[
"Computer Science"
] | null | true | null |
12799
| null |
Validated
| null | null |
null |
{
"abstract": " Design structure matrices (DSMs) are useful to represent high-level system\nstructure, modeling interactions between design entities. DSMs are used for\nmany visualization and abstraction activities. In this work, we propose the use\nof an existing DSM clustering algorithm to recover software architecture module\nviews. To make it suitable to this domain, optimization has proved necessary.\nIt was achieved through performance analysis and parameter tuning on the\noriginal algorithm. Results show that DSM clustering can be an alternative to\nother clustering algorithms.\n",
"title": "Recovery of Architecture Module Views using an Optimized Algorithm Based on Design Structure Matrices"
}
| null | null | null | null | true | null |
12800
| null |
Default
| null | null |
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