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null | prediction_agent
null | annotation
list | annotation_agent
null | multi_label
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{
"abstract": " Steady-State Visual Evoked Potentials (SSVEPs) are neural oscillations from\nthe parietal and occipital regions of the brain that are evoked from flickering\nvisual stimuli. SSVEPs are robust signals measurable in the\nelectroencephalogram (EEG) and are commonly used in brain-computer interfaces\n(BCIs). However, methods for high-accuracy decoding of SSVEPs usually require\nhand-crafted approaches that leverage domain-specific knowledge of the stimulus\nsignals, such as specific temporal frequencies in the visual stimuli and their\nrelative spatial arrangement. When this knowledge is unavailable, such as when\nSSVEP signals are acquired asynchronously, such approaches tend to fail. In\nthis paper, we show how a compact convolutional neural network (Compact-CNN),\nwhich only requires raw EEG signals for automatic feature extraction, can be\nused to decode signals from a 12-class SSVEP dataset without the need for any\ndomain-specific knowledge or calibration data. We report across subject mean\naccuracy of approximately 80% (chance being 8.3%) and show this is\nsubstantially better than current state-of-the-art hand-crafted approaches\nusing canonical correlation analysis (CCA) and Combined-CCA. Furthermore, we\nanalyze our Compact-CNN to examine the underlying feature representation,\ndiscovering that the deep learner extracts additional phase and amplitude\nrelated features associated with the structure of the dataset. We discuss how\nour Compact-CNN shows promise for BCI applications that allow users to freely\ngaze/attend to any stimulus at any time (e.g., asynchronous BCI) as well as\nprovides a method for analyzing SSVEP signals in a way that might augment our\nunderstanding about the basic processing in the visual cortex.\n",
"title": "Compact Convolutional Neural Networks for Classification of Asynchronous Steady-state Visual Evoked Potentials"
}
| null | null | null | null | true | null |
5501
| null |
Default
| null | null |
null |
{
"abstract": " Odd-frequency triplet Cooper pairs are believed to be the carriers of\nlong-range superconducting correlations in ferromagnets. Such triplet pairs are\ngenerated by inhomogeneous magnetism at the interface between a superconductor\n(S) and a ferromagnet (F). So far, reproducible long-range effects were\nreported only in complex layered structures designed to provide the magnetic\ninhomogeneity. Here we show that spin triplet pair formation can be found in\nsimple unstructured Nb/Permalloy (Py = Ni_0.8Fe_0.2)/Nb trilayers and Nb/Py\nbilayers, but only when the thickness of the ferromagnetic layer ranges between\n140 and 250 nm. The effect is related to the emergence of an intrinsically\ninhomogeneous magnetic state, which is a precursor of the well-known stripe\nregime in Py that in our samples sets in at thickness larger than 300 nm.\n",
"title": "Long-range proximity effect in Nb-based heterostructures induced by a magnetically inhomogeneous permalloy layer"
}
| null | null |
[
"Physics"
] | null | true | null |
5502
| null |
Validated
| null | null |
null |
{
"abstract": " We formulate a correspondence between affine and projective special Kähler\nmanifolds of the same dimension. As an application, we show that, under this\ncorrespondence, the affine special Kähler manifolds in the image of the rigid\nr-map are mapped to one-parameter deformations of projective special Kähler\nmanifolds in the image of the supergravity r-map. The above one-parameter\ndeformations are interpreted as perturbative $\\alpha'$-corrections in heterotic\nand type-II string compactifications with $N=2$ supersymmetry. Also affine\nspecial Kähler manifolds with quadratic prepotential are mapped to\none-parameter families of projective special Kähler manifolds with quadratic\nprepotential. We show that the completeness of the deformed supergravity r-map\nmetric depends solely on the (well-understood) completeness of the undeformed\nmetric and the sign of the deformation parameter.\n",
"title": "ASK/PSK-correspondence and the r-map"
}
| null | null | null | null | true | null |
5503
| null |
Default
| null | null |
null |
{
"abstract": " Policy evaluation is a key process in reinforcement learning. It assesses a\ngiven policy using estimation of the corresponding value function. When using a\nparameterized function to approximate the value, it is common to optimize the\nset of parameters by minimizing the sum of squared Bellman Temporal Differences\nerrors. However, this approach ignores certain distributional properties of\nboth the errors and value parameters. Taking these distributions into account\nin the optimization process can provide useful information on the amount of\nconfidence in value estimation. In this work we propose to optimize the value\nby minimizing a regularized objective function which forms a trust region over\nits parameters. We present a novel optimization method, the Kalman Optimization\nfor Value Approximation (KOVA), based on the Extended Kalman Filter. KOVA\nminimizes the regularized objective function by adopting a Bayesian perspective\nover both the value parameters and noisy observed returns. This distributional\nproperty provides information on parameter uncertainty in addition to value\nestimates. We provide theoretical results of our approach and analyze the\nperformance of our proposed optimizer on domains with large state and action\nspaces.\n",
"title": "Trust Region Value Optimization using Kalman Filtering"
}
| null | null | null | null | true | null |
5504
| null |
Default
| null | null |
null |
{
"abstract": " We present five variants of the standard Long Short-term Memory (LSTM)\nrecurrent neural networks by uniformly reducing blocks of adaptive parameters\nin the gating mechanisms. For simplicity, we refer to these models as LSTM1,\nLSTM2, LSTM3, LSTM4, and LSTM5, respectively. Such parameter-reduced variants\nenable speeding up data training computations and would be more suitable for\nimplementations onto constrained embedded platforms. We comparatively evaluate\nand verify our five variant models on the classical MNIST dataset and\ndemonstrate that these variant models are comparable to a standard\nimplementation of the LSTM model while using less number of parameters.\nMoreover, we observe that in some cases the standard LSTM's accuracy\nperformance will drop after a number of epochs when using the ReLU\nnonlinearity; in contrast, however, LSTM3, LSTM4 and LSTM5 will retain their\nperformance.\n",
"title": "Simplified Long Short-term Memory Recurrent Neural Networks: part I"
}
| null | null |
[
"Computer Science"
] | null | true | null |
5505
| null |
Validated
| null | null |
null |
{
"abstract": " This paper introduces assume/guarantee contracts on continuous-time control\nsystems, hereby extending contract theories for discrete systems to certain new\nmodel classes and specifications. Contracts are regarded as formal\ncharacterizations of control specifications, providing an alternative to\nspecifications in terms of dissipativity properties or set-invariance. The\nframework has the potential to capture a richer class of specifications more\nsuitable for complex engineering systems. The proposed contracts are supported\nby results that enable the verification of contract implementation and the\ncomparison of contracts. These results are illustrated by an example of a\nvehicle following system.\n",
"title": "Contracts as specifications for dynamical systems in driving variable form"
}
| null | null | null | null | true | null |
5506
| null |
Default
| null | null |
null |
{
"abstract": " We map the phase-space trajectories of an external-cavity semiconductor laser\nusing phase portraits. This is both a visualization tool as well as a\nthoroughly quantitative approach enabling unprecedented insight into the\ndynamical regimes, from continuous-wave through coherence collapse as feedback\nis increased. Namely, the phase portraits in the intensity versus laser-diode\nterminal-voltage (serving as a surrogate for inversion) plane are mapped out.\nWe observe a route to chaos interrupted by two types of limit cycles, a\nsubharmonic regime and period-doubled dynamics at the edge of chaos. The\ntransition of the dynamics are analyzed utilizing bifurcation diagrams for both\nthe optical intensity and the laser-diode terminal voltage. These observations\nprovide visual insight into the dynamics in these systems.\n",
"title": "Visualizing the Phase-Space Dynamics of an External Cavity Semiconductor Laser"
}
| null | null | null | null | true | null |
5507
| null |
Default
| null | null |
null |
{
"abstract": " We show that for neural network functions that have width less or equal to\nthe input dimension all connected components of decision regions are unbounded.\nThe result holds for continuous and strictly monotonic activation functions as\nwell as for ReLU activation. This complements recent results on approximation\ncapabilities of [Hanin 2017 Approximating] and connectivity of decision regions\nof [Nguyen 2018 Neural] for such narrow neural networks. Further, we give an\nexample that negatively answers the question posed in [Nguyen 2018 Neural]\nwhether one of their main results still holds for ReLU activation. Our results\nare illustrated by means of numerical experiments.\n",
"title": "On decision regions of narrow deep neural networks"
}
| null | null |
[
"Statistics"
] | null | true | null |
5508
| null |
Validated
| null | null |
null |
{
"abstract": " We prove that, under mild assumptions, a lattice in a product of semi-simple\nLie group and a totally disconnected locally compact group is, in a certain\nsense, arithmetic. We do not assume the lattice to be finitely generated or the\nambient group to be compactly generated.\n",
"title": "An adelic arithmeticity theorem for lattices in products"
}
| null | null | null | null | true | null |
5509
| null |
Default
| null | null |
null |
{
"abstract": " We present an example of a quadratic algebra given by three generators and\nthree relations, which is automaton (the set of normal words forms a regular\nlanguage) and such that its ideal of relations does not possess a finite\nGröbner basis with respect to any choice of generators and any choice of a\nwell-ordering of monomials compatible with multiplication. This answers a\nquestion of Ufnarovski.\nAnother result is a simple example (4 generators and 7 relations) of a\nquadratic algebra of intermediate growth.\n",
"title": "Quadratic automaton algebras and intermediate growth"
}
| null | null | null | null | true | null |
5510
| null |
Default
| null | null |
null |
{
"abstract": " Let $M_{l,m}$ be the total space of the $S^3$-bundle over $S^4$ classified by\nthe element $l\\sigma+m\\rho\\in{\\pi_4(SO(4))}$, $l,m\\in\\mathbb Z$. In this paper\nwe study the homotopy theory of gauge groups of principal $G$-bundles over\nmanifolds $M_{l,m}$ when $G$ is a simply connected simple compact Lie group\nsuch that $\\pi_6(G)=0$. That is, $G$ is one of the following groups: $SU(n)$\n$(n\\geq4)$, $Sp(n)$ $(n\\geq2)$, $Spin(n)$ $(n\\geq5)$, $F_4$, $E_6$, $E_7$,\n$E_8$. If the integral homology of $M_{l,m}$ is torsion-free, we describe the\nhomotopy type of the gauge groups over $M_{l,m}$ as products of recognisable\nspaces. For any manifold $M_{l,m}$ with non-torsion-free homology, we give a\n$p$-local homotopy decomposition, for a prime $p\\geq 5$, of the loop space of\nthe gauge groups.\n",
"title": "Homotopy types of gauge groups related to $S^3$-bundles over $S^4$"
}
| null | null | null | null | true | null |
5511
| null |
Default
| null | null |
null |
{
"abstract": " An analysis software was developed for the high aspect ratio optical scanning\nsystem in the Detec- tor Laboratory of the University of Helsinki and the\nHelsinki Institute of Physics. The system is used e.g. in the quality assurance\nof the GEM-TPC detectors being developed for the beam diagnostics system of the\nSuperFRS at future FAIR facility. The software was tested by analyzing five\nCERN standard GEM foils scanned with the optical scanning system. The\nmeasurement uncertainty of the diameter of the GEM holes and the pitch of the\nhole pattern was found to be 0.5 {\\mu}m and 0.3 {\\mu}m, respectively. The\nsoftware design and the performance are discussed. The correlation between the\nGEM hole size distribution and the corresponding gain variation was studied by\ncomparing them against a detailed gain mapping of a foil and a set of six lower\nprecision control measurements. It can be seen that a qualitative estimation of\nthe behavior of the local variation in gain across the GEM foil can be made\nbased on the measured sizes of the outer and inner holes.\n",
"title": "Optical quality assurance of GEM foils"
}
| null | null |
[
"Physics"
] | null | true | null |
5512
| null |
Validated
| null | null |
null |
{
"abstract": " We raise a question on the existence of continuous roots of families of monic\npolynomials (by the root of a family of polynomials we mean a function of the\ncoefficients of polynomials of a given family that maps each tuple of\ncoefficients to a root of the polynomial with these coefficients). We prove\nthat the family of monic second-degree polynomials with complex coefficients\nand the families of monic fourth-degree and fifth-degree polynomials with real\ncoefficients have no continuous root. We also prove that the family of monic\nsecond-degree polynomials with real coefficients has continuous roots and we\ndescribe the set of all such roots.\n",
"title": "On the Global Continuity of the Roots of Families of Monic Polynomials (in Russian)"
}
| null | null | null | null | true | null |
5513
| null |
Default
| null | null |
null |
{
"abstract": " Any finite word $w$ of length $n$ contains at most $n+1$ distinct palindromic\nfactors. If the bound $n+1$ is reached, the word $w$ is called rich. The number\nof rich words of length $n$ over an alphabet of cardinality $q$ is denoted\n$R_n(q)$. For binary alphabet, Rubinchik and Shur deduced that ${R_n(2)}\\leq c\n1.605^n $ for some constant $c$. We prove that $\\lim\\limits_{n\\rightarrow\n\\infty }\\sqrt[n]{R_n(q)}=1$ for any $q$, i.e. $R_n(q)$ has a subexponential\ngrowth on any alphabet.\n",
"title": "On Number of Rich Words"
}
| null | null | null | null | true | null |
5514
| null |
Default
| null | null |
null |
{
"abstract": " Understanding the feasible power flow region is of central importance to\npower system analysis. In this paper, we propose a geometric view of the power\nsystem loadability problem. By using rectangular coordinates for complex\nvoltages, we provide an integrated geometric understanding of active and\nreactive power flow equations on loadability boundaries. Based on such an\nunderstanding, we develop a linear programming framework to 1) verify if an\noperating point is on the loadability boundary, 2) compute the margin of an\noperating point to the loadability boundary, and 3) calculate a loadability\nboundary point of any direction. The proposed method is computationally more\nefficient than existing methods since it does not require solving nonlinear\noptimization problems or calculating the eigenvalues of the power flow\nJacobian. Standard IEEE test cases demonstrate the capability of the new method\ncompared to the current state-of-the-art methods.\n",
"title": "A Geometric Analysis of Power System Loadability Regions"
}
| null | null | null | null | true | null |
5515
| null |
Default
| null | null |
null |
{
"abstract": " The traditional activity of model selection aims at discovering a single\nmodel superior to other candidate models. In the presence of pronounced noise,\nhowever, multiple models are often found to explain the same data equally well.\nTo resolve this model selection ambiguity, we introduce the general approach of\nmodel selection confidence sets (MSCSs) based on likelihood ratio testing. A\nMSCS is defined as a list of models statistically indistinguishable from the\ntrue model at a user-specified level of confidence, which extends the familiar\nnotion of confidence intervals to the model-selection framework. Our approach\nguarantees asymptotically correct coverage probability of the true model when\nboth sample size and model dimension increase. We derive conditions under which\nthe MSCS contains all the relevant information about the true model structure.\nIn addition, we propose natural statistics based on the MSCS to measure\nimportance of variables in a principled way that accounts for the overall model\nuncertainty. When the space of feasible models is large, MSCS is implemented by\nan adaptive stochastic search algorithm which samples MSCS models with high\nprobability. The MSCS methodology is illustrated through numerical experiments\non synthetic data and real data examples.\n",
"title": "Model Selection Confidence Sets by Likelihood Ratio Testing"
}
| null | null |
[
"Mathematics",
"Statistics"
] | null | true | null |
5516
| null |
Validated
| null | null |
null |
{
"abstract": " In this thesis, we study connections between metric and combinatorial graphs\nfrom a Dirichlet space point of view.\n",
"title": "Analysis of Dirichlet forms on graphs"
}
| null | null | null | null | true | null |
5517
| null |
Default
| null | null |
null |
{
"abstract": " mlpack is an open-source C++ machine learning library with an emphasis on\nspeed and flexibility. Since its original inception in 2007, it has grown to be\na large project implementing a wide variety of machine learning algorithms,\nfrom standard techniques such as decision trees and logistic regression to\nmodern techniques such as deep neural networks as well as other\nrecently-published cutting-edge techniques not found in any other library.\nmlpack is quite fast, with benchmarks showing mlpack outperforming other\nlibraries' implementations of the same methods. mlpack has an active community,\nwith contributors from around the world---including some from PUST. This short\npaper describes the goals and design of mlpack, discusses how the open-source\ncommunity functions, and shows an example usage of mlpack for a simple data\nscience problem.\n",
"title": "Designing and building the mlpack open-source machine learning library"
}
| null | null |
[
"Computer Science"
] | null | true | null |
5518
| null |
Validated
| null | null |
null |
{
"abstract": " Results of Smale (1957) and Dugundji (1969) allow to compare the homotopy\ngroups of two topological spaces $X$ and $Y$ whenever a map $f:X\\to Y$ with\nstrong connectivity conditions on the fibers is given. We apply similar\ntechniques in o-minimal expansions of fields to compare the o-minimal homotopy\nof a definable set $X$ with the homotopy of some of its bounded hyperdefinable\nquotients $X/E$. Under suitable assumption, we show that $\\pi_{n}(X)^{\\rm\ndef}\\cong\\pi_{n}(X/E)$ and $\\dim(X)=\\dim_{\\mathbb R}(X/E)$. As a special case,\ngiven a definably compact group, we obtain a new proof of Pillay's group\nconjecture \"$\\dim(G)=\\dim_{\\mathbb R}(G/G^{00}$)\" largely independent of the\ngroup structure of $G$. We also obtain different proofs of various comparison\nresults between classical and o-minimal homotopy.\n",
"title": "A Vietoris-Smale mapping theorem for the homotopy of hyperdefinable sets"
}
| null | null | null | null | true | null |
5519
| null |
Default
| null | null |
null |
{
"abstract": " We express each Fréchet class of multivariate Bernoulli distributions with\ngiven margins as the convex hull of a set of densities, which belong to the\nsame Fréchet class. This characterisation allows us to establish whether a\ngiven correlation matrix is compatible with the assigned margins and, if it is,\nto easily construct one of the corresponding joint densities. % Such\n%representation is based on a polynomial expression of the distributions of a\nFréchet class. We reduce the problem of finding a density belonging to a\nFréchet class and with given correlation matrix to the solution of a linear\nsystem of equations. Our methodology also provides the bounds that each\ncorrelation must satisfy to be compatible with the assigned margins. An\nalgorithm and its use in some examples is shown.\n",
"title": "Characterization of multivariate Bernoulli distributions with given margins"
}
| null | null | null | null | true | null |
5520
| null |
Default
| null | null |
null |
{
"abstract": " We use Bonahon-Wong's trace map to study character varieties of the\nonce-punctured torus and of the 4-punctured sphere. We clarify a relationship\nwith cluster algebra associated with ideal triangulations of surfaces, and we\nshow that the Goldman Poisson algebra of loops on surfaces is recovered from\nthe Poisson structure of cluster algebra. It is also shown that cluster\nmutations give the automorphism of the character varieties. Motivated by a work\nof Chekhov-Mazzocco-Rubtsov, we revisit confluences of punctures on sphere from\ncluster algebraic viewpoint, and we obtain associated affine cubic surfaces\nconstructed by van der Put-Saito based on the Riemann-Hilbert correspondence.\nFurther studied are quantizations of character varieties by use of quantum\ncluster algebra.\n",
"title": "Note on character varieties and cluster algebras"
}
| null | null | null | null | true | null |
5521
| null |
Default
| null | null |
null |
{
"abstract": " We study a multi-period demand response problem in the smart grid with\nmultiple companies and their consumers. We model the interactions by a\nStackelberg game, where companies are the leaders and consumers are the\nfollowers. It is shown that this game has a unique equilibrium at which the\ncompanies set prices to maximize their revenues while the consumers respond\naccordingly to maximize their utilities subject to their local constraints.\nBilling minimization is achieved as an outcome of our method. Closed-form\nexpressions are provided for the strategies of all players. Based on these\nsolutions, a power allocation game has been formulated, and which is shown to\nadmit a unique pure-strategy Nash equilibrium, for which closed-form\nexpressions are provided. For privacy, we provide a distributed algorithm for\nthe computation of all strategies. We study the asymptotic behavior of\nequilibrium strategies when the numbers of periods and consumers grow. We find\nan appropriate company-to-user ratio for the large population regime.\nFurthermore, it is shown, both analytically and numerically, that the\nmulti-period scheme, compared with the single-period one, provides more\nincentives for energy consumers to participate in demand response. We have also\ncarried out case studies on real life data to demonstrate the benefits of our\napproach, including billing savings of up to 30\\%.\n",
"title": "Privacy-Preserving Multi-Period Demand Response: A Game Theoretic Approach"
}
| null | null | null | null | true | null |
5522
| null |
Default
| null | null |
null |
{
"abstract": " We determine the radio size distribution of a large sample of 152 SMGs in\nCOSMOS that were detected with ALMA at 1.3 mm. For this purpose, we used the\nobservations taken by the VLA-COSMOS 3 GHz Large Project. One hundred and\nfifteen of the 152 target SMGs were found to have a 3 GHz counterpart. The\nmedian value of the major axis FWHM at 3 GHz is derived to be $4.6\\pm0.4$ kpc.\nThe radio sizes show no evolutionary trend with redshift, or difference between\ndifferent galaxy morphologies. We also derived the spectral indices between 1.4\nand 3 GHz, and 3 GHz brightness temperatures for the sources, and the median\nvalues were found to be $\\alpha=-0.67$ and $T_{\\rm B}=12.6\\pm2$ K. Three of the\ntarget SMGs, which are also detected with the VLBA, show clearly higher\nbrightness temperatures than the typical values. Although the observed radio\nemission appears to be predominantly powered by star formation and supernova\nactivity, our results provide a strong indication of the presence of an AGN in\nthe VLBA and X-ray-detected SMG AzTEC/C61. The median radio-emitting size we\nhave derived is 1.5-3 times larger than the typical FIR dust-emitting sizes of\nSMGs, but similar to that of the SMGs' molecular gas component traced through\nmid-$J$ line emission of CO. The physical conditions of SMGs probably render\nthe diffusion of cosmic-ray electrons inefficient, and hence an unlikely\nprocess to lead to the observed extended radio sizes. Instead, our results\npoint towards a scenario where SMGs are driven by galaxy interactions and\nmergers. Besides triggering vigorous starbursts, galaxy collisions can also\npull out the magnetised fluids from the interacting disks, and give rise to a\ntaffy-like synchrotron-emitting bridge. This provides an explanation for the\nspatially extended radio emission of SMGs, and can also cause a deviation from\nthe well-known IR-radio correlation.\n",
"title": "An ALMA survey of submillimetre galaxies in the COSMOS field: The extent of the radio-emitting region revealed by 3 GHz imaging with the Very Large Array"
}
| null | null | null | null | true | null |
5523
| null |
Default
| null | null |
null |
{
"abstract": " We investigate the transport properties of pristine zigzag-edged borophene\nnanoribbons (ZBNRs) of different widths, using the fist-principles\ncalculations. We choose ZBNRs with widths of 5 and 6 as odd and even widths.\nThe differences of the quantum transport properties are found, where even-N\nBNRs and odd-N BNRs have different current-voltage relationships. Moreover, the\nnegative differential resistance (NDR) can be observed within certain bias\nrange in 5-ZBNR, while 6-ZBNR behaves as metal whose current rises with the\nincrease of the voltage. The spin filter effect of 36% can be revealed when the\ntwo electrodes have opposite magnetization direction. Furthermore, the\nmagnetoresistance effect appears to be in even-N ZBNRs, and the maximum value\ncan reach 70%.\n",
"title": "Negative differential resistance and magnetoresistance in zigzag borophene nanoribbons"
}
| null | null | null | null | true | null |
5524
| null |
Default
| null | null |
null |
{
"abstract": " The smallest eigenvalues and the associated eigenvectors (i.e., eigenpairs)\nof a graph Laplacian matrix have been widely used in spectral clustering and\ncommunity detection. However, in real-life applications the number of clusters\nor communities (say, $K$) is generally unknown a-priori. Consequently, the\nmajority of the existing methods either choose $K$ heuristically or they repeat\nthe clustering method with different choices of $K$ and accept the best\nclustering result. The first option, more often, yields suboptimal result,\nwhile the second option is computationally expensive. In this work, we propose\nan incremental method for constructing the eigenspectrum of the graph Laplacian\nmatrix. This method leverages the eigenstructure of graph Laplacian matrix to\nobtain the $K$-th smallest eigenpair of the Laplacian matrix given a collection\nof all previously computed $K-1$ smallest eigenpairs. Our proposed method\nadapts the Laplacian matrix such that the batch eigenvalue decomposition\nproblem transforms into an efficient sequential leading eigenpair computation\nproblem. As a practical application, we consider user-guided spectral\nclustering. Specifically, we demonstrate that users can utilize the proposed\nincremental method for effective eigenpair computation and for determining the\ndesired number of clusters based on multiple clustering metrics.\n",
"title": "Incremental Eigenpair Computation for Graph Laplacian Matrices: Theory and Applications"
}
| null | null | null | null | true | null |
5525
| null |
Default
| null | null |
null |
{
"abstract": " This paper presents the Speech Technology Center (STC) replay attack\ndetection systems proposed for Automatic Speaker Verification Spoofing and\nCountermeasures Challenge 2017. In this study we focused on comparison of\ndifferent spoofing detection approaches. These were GMM based methods, high\nlevel features extraction with simple classifier and deep learning frameworks.\nExperiments performed on the development and evaluation parts of the challenge\ndataset demonstrated stable efficiency of deep learning approaches in case of\nchanging acoustic conditions. At the same time SVM classifier with high level\nfeatures provided a substantial input in the efficiency of the resulting STC\nsystems according to the fusion systems results.\n",
"title": "Audio-replay attack detection countermeasures"
}
| null | null | null | null | true | null |
5526
| null |
Default
| null | null |
null |
{
"abstract": " In this paper, we study how to determine concurrent transmissions and the\ntransmission power level of each link to maximize spectrum efficiency and\nminimize energy consumption in a wireless ad hoc network. The optimal joint\ntransmission packet scheduling and power control strategy are determined when\nthe node density goes to infinity and the network area is unbounded. Based on\nthe asymptotic analysis, we determine the fundamental capacity limits of a\nwireless network, subject to an energy consumption constraint. We propose a\nscheduling and transmission power control mechanism to approach the optimal\nsolution to maximize spectrum and energy efficiencies in a practical network.\nThe distributed implementation of the proposed scheduling and transmission\npower control scheme is presented based on our MAC framework proposed in [1].\nSimulation results demonstrate that the proposed scheme achieves 40% higher\nthroughput than existing schemes. Also, the energy consumption using the\nproposed scheme is about 20% of the energy consumed using existing power saving\nMAC protocols.\n",
"title": "Joint Scheduling and Transmission Power Control in Wireless Ad Hoc Networks"
}
| null | null | null | null | true | null |
5527
| null |
Default
| null | null |
null |
{
"abstract": " The 15th International Conference on Automata and Formal Languages (AFL 2017)\nwas held in Debrecen, Hungary, from September 4 to 6, 2017. The conference was\norganized by the Faculty of Informatics of the University of Debrecen and the\nFaculty of Informatics of the Eötvös Loránd University of Budapest.\nTopics of interest covered all aspects of automata and formal languages,\nincluding theory and applications.\n",
"title": "Proceedings 15th International Conference on Automata and Formal Languages"
}
| null | null |
[
"Computer Science"
] | null | true | null |
5528
| null |
Validated
| null | null |
null |
{
"abstract": " Precise localization of nanoparticles within a cell is crucial to the\nunderstanding of cell-particle interactions and has broad applications in\nnanomedicine. Here, we report a proof-of-principle experiment for imaging\nindividual functionalized nanoparticles within a mammalian cell by correlative\nmicroscopy. Using a chemically-fixed, HeLa cell labeled with fluorescent\ncore-shell nanoparticles as a model system, we implemented a graphene-oxide\nlayer as a substrate to significantly reduce background scattering. We\nidentified cellular features of interest by fluorescence microscopy, followed\nby scanning transmission X-ray tomography to localize the particles in 3D, and\nptychographic coherent diffractive imaging of the fine features in the region\nat high resolution. By tuning the X-ray energy to the Fe L-edge, we\ndemonstrated sensitive detection of nanoparticles composed of a 22 nm magnetic\nFe3O4 core encased by a 25-nm-thick fluorescent silica (SiO2) shell. These\nfluorescent core-shell nanoparticles act as landmarks and offer clarity in a\ncellular context. Our correlative microscopy results confirmed a subset of\nparticles to be fully internalized, and high-contrast ptychographic images\nshowed two oxidation states of individual nanoparticles with a resolution of\n~16.5 nm. The ability to precisely localize individual fluorescent\nnanoparticles within mammalian cells will expand our understanding of the\nstructure/function relationships for functionalized nanoparticles.\n",
"title": "Correlative cellular ptychography with functionalized nanoparticles at the Fe L-edge"
}
| null | null | null | null | true | null |
5529
| null |
Default
| null | null |
null |
{
"abstract": " Operating in a dynamic real world environment requires a forward thinking and\nadversarial aware design for classifiers, beyond fitting the model to the\ntraining data. In such scenarios, it is necessary to make classifiers - a)\nharder to evade, b) easier to detect changes in the data distribution over\ntime, and c) be able to retrain and recover from model degradation. While most\nworks in the security of machine learning has concentrated on the evasion\nresistance (a) problem, there is little work in the areas of reacting to\nattacks (b and c). Additionally, while streaming data research concentrates on\nthe ability to react to changes to the data distribution, they often take an\nadversarial agnostic view of the security problem. This makes them vulnerable\nto adversarial activity, which is aimed towards evading the concept drift\ndetection mechanism itself. In this paper, we analyze the security of machine\nlearning, from a dynamic and adversarial aware perspective. The existing\ntechniques of Restrictive one class classifier models, Complex learning models\nand Randomization based ensembles, are shown to be myopic as they approach\nsecurity as a static task. These methodologies are ill suited for a dynamic\nenvironment, as they leak excessive information to an adversary, who can\nsubsequently launch attacks which are indistinguishable from the benign data.\nBased on empirical vulnerability analysis against a sophisticated adversary, a\nnovel feature importance hiding approach for classifier design, is proposed.\nThe proposed design ensures that future attacks on classifiers can be detected\nand recovered from. The proposed work presents motivation, by serving as a\nblueprint, for future work in the area of Dynamic-Adversarial mining, which\ncombines lessons learned from Streaming data mining, Adversarial learning and\nCybersecurity.\n",
"title": "A Dynamic-Adversarial Mining Approach to the Security of Machine Learning"
}
| null | null | null | null | true | null |
5530
| null |
Default
| null | null |
null |
{
"abstract": " Relaying on early effort estimation to predict the required number of\nresources is not often sufficient, and could lead to under or over estimation.\nIt is widely acknowledge that that software development process should be\nrefined regularly and that software prediction made at early stage of software\ndevelopment is yet kind of guesses. Even good predictions are not sufficient\nwith inherent uncertainty and risks. The stage-effort estimation allows project\nmanager to re-allocate correct number of resources, re-schedule project and\ncontrol project progress to finish on time and within budget. In this paper we\npropose an approach to utilize prior effort records to predict stage effort.\nThe proposed model combines concepts of Fuzzy set theory and association rule\nmining. The results were good in terms of prediction accuracy and have\npotential to deliver good stage-effort estimation.\n",
"title": "Software stage-effort estimation based on association rule mining and fuzzy set theory"
}
| null | null | null | null | true | null |
5531
| null |
Default
| null | null |
null |
{
"abstract": " We study the problem of approximate ranking from observations of pairwise\ninteractions. The goal is to estimate the underlying ranks of $n$ objects from\ndata through interactions of comparison or collaboration. Under a general\nframework of approximate ranking models, we characterize the exact optimal\nstatistical error rates of estimating the underlying ranks. We discover\nimportant phase transition boundaries of the optimal error rates. Depending on\nthe value of the signal-to-noise ratio (SNR) parameter, the optimal rate, as a\nfunction of SNR, is either trivial, polynomial, exponential or zero. The four\ncorresponding regimes thus have completely different error behaviors. To the\nbest of our knowledge, this phenomenon, especially the phase transition between\nthe polynomial and the exponential rates, has not been discovered before.\n",
"title": "Phase Transitions in Approximate Ranking"
}
| null | null |
[
"Mathematics",
"Statistics"
] | null | true | null |
5532
| null |
Validated
| null | null |
null |
{
"abstract": " We address the problem of finding influential training samples for a\nparticular case of tree ensemble-based models, e.g., Random Forest (RF) or\nGradient Boosted Decision Trees (GBDT). A natural way of formalizing this\nproblem is studying how the model's predictions change upon leave-one-out\nretraining, leaving out each individual training sample. Recent work has shown\nthat, for parametric models, this analysis can be conducted in a\ncomputationally efficient way. We propose several ways of extending this\nframework to non-parametric GBDT ensembles under the assumption that tree\nstructures remain fixed. Furthermore, we introduce a general scheme of\nobtaining further approximations to our method that balance the trade-off\nbetween performance and computational complexity. We evaluate our approaches on\nvarious experimental setups and use-case scenarios and demonstrate both the\nquality of our approach to finding influential training samples in comparison\nto the baselines and its computational efficiency.\n",
"title": "Finding Influential Training Samples for Gradient Boosted Decision Trees"
}
| null | null | null | null | true | null |
5533
| null |
Default
| null | null |
null |
{
"abstract": " In a network, a local disturbance can propagate and eventually cause a\nsubstantial part of the system to fail, in cascade events that are easy to\nconceptualize but extraordinarily difficult to predict. Here, we develop a\nstatistical framework that can predict cascade size distributions by\nincorporating two ingredients only: the vulnerability of individual components\nand the co-susceptibility of groups of components (i.e., their tendency to fail\ntogether). Using cascades in power grids as a representative example, we show\nthat correlations between component failures define structured and often\nsurprisingly large groups of co-susceptible components. Aside from their\nimplications for blackout studies, these results provide insights and a new\nmodeling framework for understanding cascades in financial systems, food webs,\nand complex networks in general.\n",
"title": "Vulnerability and co-susceptibility determine the size of network cascades"
}
| null | null | null | null | true | null |
5534
| null |
Default
| null | null |
null |
{
"abstract": " In this paper, we present a transfer learning approach for music\nclassification and regression tasks. We propose to use a pre-trained convnet\nfeature, a concatenated feature vector using the activations of feature maps of\nmultiple layers in a trained convolutional network. We show how this convnet\nfeature can serve as general-purpose music representation. In the experiments,\na convnet is trained for music tagging and then transferred to other\nmusic-related classification and regression tasks. The convnet feature\noutperforms the baseline MFCC feature in all the considered tasks and several\nprevious approaches that are aggregating MFCCs as well as low- and high-level\nmusic features.\n",
"title": "Transfer learning for music classification and regression tasks"
}
| null | null | null | null | true | null |
5535
| null |
Default
| null | null |
null |
{
"abstract": " In a standard bifurcation of a dynamical system, the stationary points (or\nmore generally attractors) change qualitatively when varying a control\nparameter. Here we describe a novel unusual effect, when the change of a\nparameter, e.g. a growth rate, does not influence the stationary states, but\nnevertheless leads to a qualitative change of dynamics. For instance, such a\ndynamic transition can be between the convergence to a stationary state and a\nstrong increase without stationary states, or between the convergence to one\nstationary state and that to a different state. This effect is illustrated for\na dynamical system describing two symbiotic populations, one of which exhibits\na growth rate larger than the other one. We show that, although the stationary\nstates of the dynamical system do not depend on the growth rates, the latter\ninfluence the boundary of the basins of attraction. This change of the basins\nof attraction explains this unusual effect of the quantitative change of\ndynamics by growth rate variation.\n",
"title": "Dynamic Transition in Symbiotic Evolution Induced by Growth Rate Variation"
}
| null | null | null | null | true | null |
5536
| null |
Default
| null | null |
null |
{
"abstract": " The anomalous metallic state in high-temperature superconducting cuprates is\nmasked by the onset of superconductivity near a quantum critical point. Use of\nhigh magnetic fields to suppress superconductivity has enabled a detailed study\nof the ground state in these systems. Yet, the direct effect of strong magnetic\nfields on the metallic behavior at low temperatures is poorly understood,\nespecially near critical doping, $x=0.19$. Here we report a high-field\nmagnetoresistance study of thin films of \\LSCO cuprates in close vicinity to\ncritical doping, $0.161\\leq x\\leq0.190$. We find that the metallic state\nexposed by suppressing superconductivity is characterized by a\nmagnetoresistance that is linear in magnetic field up to the highest measured\nfields of $80$T. The slope of the linear-in-field resistivity is\ntemperature-independent at very high fields. It mirrors the magnitude and\ndoping evolution of the linear-in-temperature resistivity that has been\nascribed to Planckian dissipation near a quantum critical point. This\nestablishes true scale-invariant conductivity as the signature of the strange\nmetal state in the high-temperature superconducting cuprates.\n",
"title": "Scale-invariant magnetoresistance in a cuprate superconductor"
}
| null | null |
[
"Physics"
] | null | true | null |
5537
| null |
Validated
| null | null |
null |
{
"abstract": " The principles of the thermoelectric phenomenon, including Seebeck effect,\nPeltier effect, and Thomson effect are discussed. The dependence of the\nthermoelectric devices on the figure of merit, Seebeck coefficient, electrical\nconductivity, and thermal conductivity are explained in details. The paper\nprovides an overview of the different types of thermoelectric materials,\nexplains the techniques used to grow thin films for these materials, and\ndiscusses future research and development trends for this technology.\n",
"title": "Thermoelectric Devices: Principles and Future Trends"
}
| null | null | null | null | true | null |
5538
| null |
Default
| null | null |
null |
{
"abstract": " Strong disorder in interacting quantum systems can give rise to the\nphenomenon of Many-Body Localization (MBL), which defies thermalization due to\nthe formation of an extensive number of quasi local integrals of motion. The\none particle operator content of these integrals of motion is related to the\none particle orbitals of the one particle density matrix and shows a strong\nsignature across the MBL transition as recently pointed out by Bera et al.\n[Phys. Rev. Lett. 115, 046603 (2015); Ann. Phys. 529, 1600356 (2017)]. We study\nthe properties of the one particle orbitals of many-body eigenstates of an MBL\nsystem in one dimension. Using shift-and-invert MPS (SIMPS), a matrix product\nstate method to target highly excited many-body eigenstates introduced in\n[Phys. Rev. Lett. 118, 017201 (2017)], we are able to obtain accurate results\nfor large systems of sizes up to L = 64. We find that the one particle orbitals\ndrawn from eigenstates at different energy densities have high overlap and\ntheir occupations are correlated with the energy of the eigenstates. Moreover,\nthe standard deviation of the inverse participation ratio of these orbitals is\nmaximal at the nose of the mobility edge. Also, the one particle orbitals decay\nexponentially in real space, with a correlation length that increases at low\ndisorder. In addition, we find a 1/f distribution of the coupling constants of\na certain range of the number operators of the OPOs, which is related to their\nexponential decay.\n",
"title": "Exploring one particle orbitals in large Many-Body Localized systems"
}
| null | null | null | null | true | null |
5539
| null |
Default
| null | null |
null |
{
"abstract": " The aim of this paper is to present a comprehensive review of method of the\nwave-front expansion, also known in the literature as the Buchen-Mainardi\nalgorithm. In particular, many applications of this technique to the\nfundamental models of both ordinary and fractional linear viscoelasticity are\nthoroughly presented and discussed.\n",
"title": "On transient waves in linear viscoelasticity"
}
| null | null | null | null | true | null |
5540
| null |
Default
| null | null |
null |
{
"abstract": " We report on the detection at $>$98% confidence of an optical counterpart to\nAGC 249525, an Ultra-Compact High Velocity Cloud (UCHVC) discovered by the\nALFALFA blind neutral hydrogen survey. UCHVCs are compact, isolated HI clouds\nwith properties consistent with their being nearby low-mass galaxies, but\nwithout identified counterparts in extant optical surveys. Analysis of the\nresolved stellar sources in deep $g$- and $i$-band imaging from the WIYN pODI\ncamera reveals a clustering of possible Red Giant Branch stars associated with\nAGC 249525 at a distance of 1.64$\\pm$0.45 Mpc. Matching our optical detection\nwith the HI synthesis map of AGC 249525 from Adams et al. (2016) shows that the\nstellar overdensity is exactly coincident with the highest-density HI contour\nfrom that study. Combining our optical photometry and the HI properties of this\nobject yields an absolute magnitude of $-7.1 \\leq M_V \\leq -4.5$, a stellar\nmass between $2.2\\pm0.6\\times10^4 M_{\\odot}$ and $3.6\\pm1.0\\times10^5\nM_{\\odot}$, and an HI to stellar mass ratio between 9 and 144. This object has\nstellar properties within the observed range of gas-poor Ultra-Faint Dwarfs in\nthe Local Group, but is gas-dominated.\n",
"title": "Detection of an Optical Counterpart to the ALFALFA Ultra-compact High Velocity Cloud AGC 249525"
}
| null | null | null | null | true | null |
5541
| null |
Default
| null | null |
null |
{
"abstract": " A particularly promising pathway to enhance the efficiency of thermoelectric\nmaterials lies in the use of resonant states, as suggested by experimentalists\nand theorists alike. In this paper, we go over the mechanisms used in the\nliterature to explain how resonant levels affect the thermoelectric properties,\nand we suggest that the effects of hybridization are crucial yet\nill-understood. In order to get a good grasp of the physical picture and to\ndraw guidelines for thermoelectric enhancement, we use a tight-binding model\ncontaining a conduction band hybridized with a flat band. We find that the\nconductivity is suppressed in a wide energy range near the resonance, but that\nthe Seebeck coefficient can be boosted for strong enough hybridization, thus\nallowing for a significant increase of the power factor. The Seebeck\ncoefficient can also display a sign change as the Fermi level crosses the\nresonance. Our results suggest that in order to boost the power factor, the\nhybridization strength must not be too low, the resonant level must not be too\nclose to the conduction (or valence) band edge, and the Fermi level must be\nlocated around, but not inside, the resonant peak.\n",
"title": "Boosting the power factor with resonant states: a model study"
}
| null | null | null | null | true | null |
5542
| null |
Default
| null | null |
null |
{
"abstract": " Additional experimental cross sections were deduced for the long half-life\nactivation products (172Hf and 173Lu) from the alpha particle induced reactions\non ytterbium up to 38 MeV from late, long measurements and for 175Yb, 167Tm\nfrom a re-evaluation of earlier measured spectra. The cross-sections are\ncompared with the earlier experimental datasets and with the data based on the\nTALYS theoretical nuclear reaction model (available in the TENDL-2014 and 2015\nlibraries) and the ALICE-IPPE code.\n",
"title": "Activation cross-section data for alpha-particle induced nuclear reactions on natural ytterbium for some longer lived radioisotopes"
}
| null | null | null | null | true | null |
5543
| null |
Default
| null | null |
null |
{
"abstract": " Intelligent network selection plays an important role in achieving an\neffective data offloading in the integrated cellular and Wi-Fi networks.\nHowever, previously proposed network selection schemes mainly focused on\noffloading as much data traffic to Wi-Fi as possible, without systematically\nconsidering the Wi-Fi network congestion and the ping-pong effect, both of\nwhich may lead to a poor overall user quality of experience. Thus, in this\npaper, we study a more practical network selection problem by considering both\nthe impacts of the network congestion and switching penalties. More\nspecifically, we formulate the users' interactions as a Bayesian network\nselection game (NSG) under the incomplete information of the users' mobilities.\nWe prove that it is a Bayesian potential game and show the existence of a pure\nBayesian Nash equilibrium that can be easily reached. We then propose a\ndistributed network selection (DNS) algorithm based on the network congestion\nstatistics obtained from the operator. Furthermore, we show that computing the\noptimal centralized network allocation is an NP-hard problem, which further\njustifies our distributed approach. Simulation results show that the DNS\nalgorithm achieves the highest user utility and a good fairness among users, as\ncompared with the on-the-spot offloading and cellular-only benchmark schemes.\n",
"title": "Congestion-Aware Distributed Network Selection for Integrated Cellular and Wi-Fi Networks"
}
| null | null | null | null | true | null |
5544
| null |
Default
| null | null |
null |
{
"abstract": " High-resolution satellite imagery have been increasingly used on remote\nsensing classification problems. One of the main factors is the availability of\nthis kind of data. Even though, very little effort has been placed on the zebra\ncrossing classification problem. In this letter, crowdsourcing systems are\nexploited in order to enable the automatic acquisition and annotation of a\nlarge-scale satellite imagery database for crosswalks related tasks. Then, this\ndataset is used to train deep-learning-based models in order to accurately\nclassify satellite images that contains or not zebra crossings. A novel dataset\nwith more than 240,000 images from 3 continents, 9 countries and more than 20\ncities was used in the experiments. Experimental results showed that freely\navailable crowdsourcing data can be used to accurately (97.11%) train robust\nmodels to perform crosswalk classification on a global scale.\n",
"title": "Deep Learning Based Large-Scale Automatic Satellite Crosswalk Classification"
}
| null | null |
[
"Computer Science",
"Statistics"
] | null | true | null |
5545
| null |
Validated
| null | null |
null |
{
"abstract": " Newton's method for finding an unconstrained minimizer for strictly convex\nfunctions, generally speaking, does not converge from any starting point.\nWe introduce and study the damped regularized Newton's method (DRNM). It\nconverges globally for any strictly convex function, which has a minimizer in\n$R^n$.\nLocally DRNM converges with a quadratic rate. We characterize the\nneighborhood of the minimizer, where the quadratic rate occurs. Based on it we\nestimate the number of DRNM's steps required for finding an $\\varepsilon$-\napproximation for the minimizer.\n",
"title": "Complexity of the Regularized Newton Method"
}
| null | null | null | null | true | null |
5546
| null |
Default
| null | null |
null |
{
"abstract": " With the range and sensitivity of algorithmic decisions expanding at a\nbreak-neck speed, it is imperative that we aggressively investigate whether\nprograms are biased. We propose a novel probabilistic program analysis\ntechnique and apply it to quantifying bias in decision-making programs.\nSpecifically, we (i) present a sound and complete automated verification\ntechnique for proving quantitative properties of probabilistic programs; (ii)\nshow that certain notions of bias, recently proposed in the fairness\nliterature, can be phrased as quantitative correctness properties; and (iii)\npresent FairSquare, the first verification tool for quantifying program bias,\nand evaluate it on a range of decision-making programs.\n",
"title": "Quantifying Program Bias"
}
| null | null |
[
"Computer Science"
] | null | true | null |
5547
| null |
Validated
| null | null |
null |
{
"abstract": " Exoplanet transit spectroscopy enables the characterization of distant\nworlds, and will yield key results for NASA's James Webb Space Telescope.\nHowever, transit spectra models are often simplified, omitting potentially\nimportant processes like refraction and multiple scattering. While the former\nprocess has seen recent development, the effects of light multiple scattering\non exoplanet transit spectra has received little attention. Here, we develop a\ndetailed theory of exoplanet transit spectroscopy that extends to the full\nrefracting and multiple scattering case. We explore the importance of\nscattering for planet-wide cloud layers, where the relevant parameters are the\nslant scattering optical depth, the scattering asymmetry parameter, and the\nangular size of the host star. The latter determines the size of the \"target\"\nfor a photon that is back-mapped from an observer. We provide results that\nstraightforwardly indicate the potential importance of multiple scattering for\ntransit spectra. When the orbital distance is smaller than 10-20 times the\nstellar radius, multiple scattering effects for aerosols with asymmetry\nparameters larger than 0.8-0.9 can become significant. We provide examples of\nthe impacts of cloud/haze multiple scattering on transit spectra of a hot\nJupiter-like exoplanet. For cases with a forward and conservatively scattering\ncloud/haze, differences due to multiple scattering effects can exceed 200 ppm,\nbut shrink to zero at wavelength ranges corresponding to strong gas absorption\nor when the slant optical depth of the cloud exceeds several tens. We conclude\nwith a discussion of types of aerosols for which multiple scattering in transit\nspectra may be important.\n",
"title": "A Theory of Exoplanet Transits with Light Scattering"
}
| null | null |
[
"Physics"
] | null | true | null |
5548
| null |
Validated
| null | null |
null |
{
"abstract": " We study a superconductor-normal state-superconductor (SNS) Josephson\njunction along the edge of a quantum spin Hall insulator (QSHI) with a\nsuperconducting $\\pi$-phase across the junction. We solve self-consistently for\nthe superconducting order parameter and find both real junctions, where the\norder parameter is fully real throughout the system, and junctions where the\norder parameter has a complex phase winding. Real junctions host two Majorana\nzero modes (MZMs), while phase-winding junctions have no subgap states close to\nzero energy. At zero temperature we find that the phase-winding solution always\nhas the lowest free energy, which we establish being due to a strong\nproximity-effect into the N region. With increasing temperature this\nproximity-effect is dramatically decreased and we find a phase transition into\na real junction with two MZMs.\n",
"title": "Tuning Majorana zero modes with temperature in $π$-phase Josephson junctions"
}
| null | null |
[
"Physics"
] | null | true | null |
5549
| null |
Validated
| null | null |
null |
{
"abstract": " A skyrmion racetrack design is proposed that allows for thermally stable\nskyrmions to code information and dynamical pinning sites that move with the\napplied current. This concept solves the problem of intrinsic distributions of\npinning times and pinning currents of skyrmions at static geometrical or\nmagnetic pinning sites. The dynamical pinning sites are realized by a skyrmion\ncarrying wire, where the skyrmion repulsion is used in order to keep the\nskyrmions at equal distances. The information is coded by an additional layer\nwhere the presence and absence of a skyrmion is used to code the information.\nThe lowest energy barrier for a data loss is calculated to be DE = 55 kBT300\nwhich is sufficient for long time thermal stability.\n",
"title": "A repulsive skyrmion chain as guiding track for a race track memory"
}
| null | null |
[
"Physics"
] | null | true | null |
5550
| null |
Validated
| null | null |
null |
{
"abstract": " Detection with high dimensional multimodal data is a challenging problem when\nthere are complex inter- and intra- modal dependencies. While several\napproaches have been proposed for dependent data fusion (e.g., based on copula\ntheory), their advantages come at a high price in terms of computational\ncomplexity. In this paper, we treat the detection problem with compressive\nsensing (CS) where compression at each sensor is achieved via low dimensional\nrandom projections. CS has recently been exploited to solve detection problems\nunder various assumptions on the signals of interest, however, its potential\nfor dependent data fusion has not been explored adequately. We exploit the\ncapability of CS to capture statistical properties of uncompressed data in\norder to compute decision statistics for detection in the compressed domain.\nFirst, a Gaussian approximation is employed to perform likelihood ratio (LR)\nbased detection with compressed data. In this approach, inter-modal dependence\nis captured via a compressed version of the covariance matrix of the\nconcatenated (temporally and spatially) uncompressed data vector. We show that,\nunder certain conditions, this approach with a small number of compressed\nmeasurements per node leads to enhanced performance compared to detection with\nuncompressed data using widely considered suboptimal approaches. Second, we\ndevelop a nonparametric approach where a decision statistic based on the second\norder statistics of uncompressed data is computed in the compressed domain. The\nsecond approach is promising over other related nonparametric approaches and\nthe first approach when multimodal data is highly correlated at the expense of\nslightly increased computational complexity.\n",
"title": "Compressive Sensing-Based Detection with Multimodal Dependent Data"
}
| null | null | null | null | true | null |
5551
| null |
Default
| null | null |
null |
{
"abstract": " Polarization is a troubling phenomenon that can lead to societal divisions\nand hurt the democratic process. It is therefore important to develop methods\nto reduce it.\nWe propose an algorithmic solution to the problem of reducing polarization.\nThe core idea is to expose users to content that challenges their point of\nview, with the hope broadening their perspective, and thus reduce their\npolarity. Our method takes into account several aspects of the problem, such as\nthe estimated polarity of the user, the probability of accepting the\nrecommendation, the polarity of the content, and popularity of the content\nbeing recommended.\nWe evaluate our recommendations via a large-scale user study on Twitter users\nthat were actively involved in the discussion of the US elections results.\nResults shows that, in most cases, the factors taken into account in the\nrecommendation affect the users as expected, and thus capture the essential\nfeatures of the problem.\n",
"title": "Factors in Recommending Contrarian Content on Social Media"
}
| null | null | null | null | true | null |
5552
| null |
Default
| null | null |
null |
{
"abstract": " Turbulence remains an unsolved multidisciplinary science problem. As one of\nthe most well-known examples in turbulent flows, knowledge of the logarithmic\nmean velocity profile (MVP), so called the log law of the wall, plays an\nimportant role everywhere turbulent flow meets the solid wall, such as fluids\nin any kind of channels, skin friction of all types of transportations, the\natmospheric wind on a planetary ground, and the oceanic current on the seabed.\nHowever, the mechanism of how this log-law MVP is formed under the multiscale\nnature of turbulent shears remains one of the greatest interests of turbulence\npuzzles. To untangle the multiscale coupling of turbulent shear stresses, we\nexplore for a known fundamental tool in physics. Here we present how to\nreproduce the log-law MVP with the even harmonic modes of fixed-end standing\nwaves. We find that when these harmonic waves of same magnitude are considered\nas the multiscale turbulent shear stresses, the wave envelope of their\nsuperposition simulates the mean shear stress profile of the wall-bounded flow.\nIt implies that the log-law MVP is not expectedly related to the turbulent\nscales in the inertial subrange associated with the Kolmogorov energy cascade,\nrevealing the dissipative nature of all scales involved. The MVP with reduced\nharmonic modes also shows promising connection to the understanding of flow\ntransition to turbulence. The finding here suggests the simple harmonic waves\nas good agents to help unravel the complex turbulent dynamics in wall-bounded\nflow.\n",
"title": "Generating the Log Law of the Wall with Superposition of Standing Waves"
}
| null | null |
[
"Physics"
] | null | true | null |
5553
| null |
Validated
| null | null |
null |
{
"abstract": " Weighting the p-values is a well-established strategy that improves the power\nof multiple testing procedures while dealing with heterogeneous data. However,\nhow to achieve this task in an optimal way is rarely considered in the\nliterature. This paper contributes to fill the gap in the case of\ngroup-structured null hypotheses, by introducing a new class of procedures\nnamed ADDOW (for Adaptive Data Driven Optimal Weighting) that adapts both to\nthe alternative distribution and to the proportion of true null hypotheses. We\nprove the asymptotical FDR control and power optimality among all weighted\nprocedures of ADDOW, which shows that it dominates all existing procedures in\nthat framework. Some numerical experiments show that the proposed method\npreserves its optimal properties in the finite sample setting when the number\nof tests is moderately large.\n",
"title": "Adaptive p-value weighting with power optimality"
}
| null | null |
[
"Mathematics",
"Statistics"
] | null | true | null |
5554
| null |
Validated
| null | null |
null |
{
"abstract": " Understanding the dynamics of social interactions is crucial to comprehend\nhuman behavior. The emergence of online social media has enabled access to data\nregarding people relationships at a large scale. Twitter, specifically, is an\ninformation oriented network, with users sharing and consuming information. In\nthis work, we study whether users tend to be in contact with people interested\nin similar topics, i.e., topical homophily. To do so, we propose an approach\nbased on the use of hashtags to extract information topics from Twitter\nmessages and model users' interests. Our results show that, on average, users\nare connected with other users similar to them and stronger relationships are\ndue to a higher topical similarity. Furthermore, we show that topical homophily\nprovides interesting information that can eventually allow inferring users'\nconnectivity. Our work, besides providing a way to assess the topical\nsimilarity of users, quantifies topical homophily among individuals,\ncontributing to a better understanding of how complex social systems are\nstructured.\n",
"title": "Topical homophily in online social systems"
}
| null | null | null | null | true | null |
5555
| null |
Default
| null | null |
null |
{
"abstract": " Cognition does not only depend on bottom-up sensor feature abstraction, but\nalso relies on contextual information being passed top-down. Context is higher\nlevel information that helps to predict belief states at lower levels. The main\ncontribution of this paper is to provide a formalisation of perceptual context\nand its integration into a new process model for cognitive hierarchies. Several\nsimple instantiations of a cognitive hierarchy are used to illustrate the role\nof context. Notably, we demonstrate the use context in a novel approach to\nvisually track the pose of rigid objects with just a 2D camera.\n",
"title": "Perceptual Context in Cognitive Hierarchies"
}
| null | null | null | null | true | null |
5556
| null |
Default
| null | null |
null |
{
"abstract": " Presentations for unbraided, braided and symmetric pseudomonoids are defined.\nBiequivalences characterising the semistrict bicategories generated by these\npresentations are proven. It is shown that these biequivalences categorify\nresults in the theory of monoids and commutative monoids, and generalise\nstandard coherence theorems for braided and symmetric monoidal categories.\n",
"title": "Coherence for braided and symmetric pseudomonoids"
}
| null | null |
[
"Computer Science",
"Mathematics"
] | null | true | null |
5557
| null |
Validated
| null | null |
null |
{
"abstract": " Linear optimal power flow (LOPF) algorithms use a linearization of the\nalternating current (AC) load flow equations to optimize generator dispatch in\na network subject to the loading constraints of the network branches. Common\nalgorithms use the voltage angles at the buses as optimization variables, but\nalternatives can be computationally advantageous. In this article we provide a\nreview of existing methods and describe a new formulation that expresses the\nloading constraints directly in terms of the flows themselves, using a\ndecomposition of the network graph into a spanning tree and closed cycles. We\nprovide a comprehensive study of the computational performance of the various\nformulations, in settings that include computationally challenging applications\nsuch as multi-period LOPF with storage dispatch and generation capacity\nexpansion. We show that the new formulation of the LOPF solves up to 7 times\nfaster than the angle formulation using a commercial linear programming solver,\nwhile another existing cycle-based formulation solves up to 20 times faster,\nwith an average speed-up of factor 3 for the standard networks considered here.\nIf generation capacities are also optimized, the average speed-up rises to a\nfactor of 12, reaching up to factor 213 in a particular instance. The speed-up\nis largest for networks with many buses and decentral generators throughout the\nnetwork, which is highly relevant given the rise of distributed renewable\ngeneration and the computational challenge of operation and planning in such\nnetworks.\n",
"title": "Linear Optimal Power Flow Using Cycle Flows"
}
| null | null | null | null | true | null |
5558
| null |
Default
| null | null |
null |
{
"abstract": " This article is a review by the authors concerning the construction of a\nPoincar${\\rm \\acute{e}}$ covariant (owing to spacetime continuum)\nfield-theoretic formalism in terms of step-function-type basis functions\nwithout ultraviolet divergences. This formalism analytically derives\nconfinement/deconfinement, mass-gap and Regge trajectory for non-Abelian gauge\nfields, and gives solutions for self-interacting scalar fields. Fields\npropagate in spacetime continuum and fields with finite degrees of freedom\ntoward continuum limit have no ultraviolet divergence. Basis functions defined\nin a parameter spacetime are mapped to real spacetime. The authors derive a new\nsolution comprised of classical fields as a vacuum and quantum fluctuations,\nleading to the linear potential between the particle and antiparticle from the\nWilson loop. The Polyakov line gives finite binding energies and reveals the\ndeconfining property at high temperatures. The quantum action yields positive\nmass from the classical fields and quantum fluctuations produces the Coulomb\npotential. Pure Yang-Mills fields show the same mass-gap owing to the\nparticle-antiparticle pair creation. The Dirac equation under linear potential\nis analytically solved in this formalism, reproducing the principal properties\nof Regge trajectories at a quantum level. Further outlook mentions a\npossibility of the difference between conventional continuum and present wave\nfunctions responsible for the cosmological constant.\n",
"title": "Toward construction of a consistent field theory with Poincare covariance in terms of step-function-type basis functions showing confinement/deconfinement, mass-gap and Regge trajectory for non-pure/pure non-Abelian gauge fields"
}
| null | null | null | null | true | null |
5559
| null |
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| null | null |
null |
{
"abstract": " We study rank-1 {L1-norm-based TUCKER2} (L1-TUCKER2) decomposition of 3-way\ntensors, treated as a collection of $N$ $D \\times M$ matrices that are to be\njointly decomposed. Our contributions are as follows. i) We prove that the\nproblem is equivalent to combinatorial optimization over $N$ antipodal-binary\nvariables. ii) We derive the first two algorithms in the literature for its\nexact solution. The first algorithm has cost exponential in $N$; the second one\nhas cost polynomial in $N$ (under a mild assumption). Our algorithms are\naccompanied by formal complexity analysis. iii) We conduct numerical studies to\ncompare the performance of exact L1-TUCKER2 (proposed) with standard HOSVD,\nHOOI, GLRAM, PCA, L1-PCA, and TPCA-L1. Our studies show that L1-TUCKER2\noutperforms (in tensor approximation) all the above counterparts when the\nprocessed data are outlier corrupted.\n",
"title": "The Exact Solution to Rank-1 L1-norm TUCKER2 Decomposition"
}
| null | null | null | null | true | null |
5560
| null |
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| null | null |
null |
{
"abstract": " The search for habitable exoplanets and life beyond the Solar System is one\nof the most compelling scientific opportunities of our time. Nevertheless, the\nhigh cost of building facilities that can address this topic and the keen\npublic interest in the results of such research requires the rigorous\ndevelopment of experiments that can deliver a definitive advance in our\nunderstanding. Most work to date in this area has focused on a \"systems\nscience\" approach of obtaining and interpreting comprehensive data for\nindividual planets to make statements about their habitability and the\npossibility that they harbor life. This strategy is challenging because of the\ndiversity of exoplanets, both observed and expected, and the limited\ninformation that can be obtained with astronomical instruments. Here we propose\na complementary approach that is based on performing surveys of key planetary\ncharacteristics and using statistical marginalization to answer broader\nquestions than can be addressed with a small sample of objects. The fundamental\nprinciple of this comparative planetology approach is maximizing what can be\nlearned from each type of measurement by applying it widely rather than\nrequiring that multiple kinds of observations be brought to bear on a single\nobject. As a proof of concept, we outline a survey of terrestrial exoplanet\natmospheric water and carbon dioxide abundances that would test the habitable\nzone hypothesis and lead to a deeper understanding of the frequency of\nhabitable planets. We also discuss ideas for additional surveys that could be\ndeveloped to test other foundational hypotheses is this area.\n",
"title": "A Statistical Comparative Planetology Approach to the Hunt for Habitable Exoplanets and Life Beyond the Solar System"
}
| null | null | null | null | true | null |
5561
| null |
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| null | null |
null |
{
"abstract": " Convolutional autoregressive models have recently demonstrated\nstate-of-the-art performance on a number of generation tasks. While fast,\nparallel training methods have been crucial for their success, generation is\ntypically implemented in a naïve fashion where redundant computations are\nunnecessarily repeated. This results in slow generation, making such models\ninfeasible for production environments. In this work, we describe a method to\nspeed up generation in convolutional autoregressive models. The key idea is to\ncache hidden states to avoid redundant computation. We apply our fast\ngeneration method to the Wavenet and PixelCNN++ models and achieve up to\n$21\\times$ and $183\\times$ speedups respectively.\n",
"title": "Fast Generation for Convolutional Autoregressive Models"
}
| null | null | null | null | true | null |
5562
| null |
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| null | null |
null |
{
"abstract": " Autoreactive B cells have a central role in the pathogenesis of rheumatoid\narthritis (RA), and recent findings have proposed that anti-citrullinated\nprotein autoantibodies (ACPA) may be directly pathogenic. Herein, we\ndemonstrate the frequency of variable-region glycosylation in single-cell\ncloned mAbs. A total of 14 ACPA mAbs were evaluated for predicted N-linked\nglycosylation motifs in silico and compared to 452 highly-mutated mAbs from RA\npatients and controls. Variable region N-linked motifs (N-X-S/T) were\nstrikingly prevalent within ACPA (100%) compared to somatically hypermutated\n(SHM) RA bone marrow plasma cells (21%), and synovial plasma cells from\nseropositive (39%) and seronegative RA (7%). When normalized for SHM, ACPA\nstill had significantly higher frequency of N-linked motifs compared to all\nstudied mAbs including highly-mutated HIV broadly-neutralizing and\nmalaria-associated mAbs. The Fab glycans of ACPA-mAbs were highly sialylated,\ncontributed to altered charge, but did not influence antigen binding. The\nanalysis revealed evidence of unusual B-cell selection pressure and\nSHM-mediated decreased in surface charge and isoelectric point in ACPA. It is\nstill unknown how these distinct features of anti-citrulline immunity may have\nan impact on pathogenesis. However, it is evident that they offer selective\nadvantages for ACPA+ B cells, possibly also through non-antigen driven\nmechanisms.\n",
"title": "Variable domain N-linked glycosylation and negative surface charge are key features of monoclonal ACPA: implications for B-cell selection"
}
| null | null | null | null | true | null |
5563
| null |
Default
| null | null |
null |
{
"abstract": " We establish an exact mapping between (i) the equilibrium (imaginary time)\ndynamics of non-interacting fermions trapped in a harmonic potential at\ntemperature $T=1/\\beta$ and (ii) non-intersecting Ornstein-Uhlenbeck (OU)\nparticles constrained to return to their initial positions after time $\\beta$.\nExploiting the determinantal structure of the process we compute the universal\ncorrelation functions both in the bulk and at the edge of the trapped Fermi\ngas. The latter corresponds to the top path of the non-intersecting OU\nparticles, and leads us to introduce and study the time-periodic Airy$_2$\nprocess, ${\\cal A}^b_2(u)$, depending on a single parameter, the period $b$.\nThe standard Airy$_2$ process is recovered for $b=+\\infty$. We discuss\napplications of our results to the real time quantum dynamics of trapped\nfermions.\n",
"title": "Periodic Airy process and equilibrium dynamics of edge fermions in a trap"
}
| null | null |
[
"Physics",
"Mathematics"
] | null | true | null |
5564
| null |
Validated
| null | null |
null |
{
"abstract": " Recently, increased computational power and data availability, as well as\nalgorithmic advances, have led machine learning techniques to impressive\nresults in regression, classification, data-generation and reinforcement\nlearning tasks. Despite these successes, the proximity to the physical limits\nof chip fabrication alongside the increasing size of datasets are motivating a\ngrowing number of researchers to explore the possibility of harnessing the\npower of quantum computation to speed-up classical machine learning algorithms.\nHere we review the literature in quantum machine learning and discuss\nperspectives for a mixed readership of classical machine learning and quantum\ncomputation experts. Particular emphasis will be placed on clarifying the\nlimitations of quantum algorithms, how they compare with their best classical\ncounterparts and why quantum resources are expected to provide advantages for\nlearning problems. Learning in the presence of noise and certain\ncomputationally hard problems in machine learning are identified as promising\ndirections for the field. Practical questions, like how to upload classical\ndata into quantum form, will also be addressed.\n",
"title": "Quantum machine learning: a classical perspective"
}
| null | null | null | null | true | null |
5565
| null |
Default
| null | null |
null |
{
"abstract": " Research on human-robot collaboration or human-robot teaming, has focused\npredominantly on understanding and enabling collaboration between a single\nrobot and a single human. Extending human-robot collaboration research beyond\nthe dyad, raises novel questions about how a robot should distribute resources\namong group members and about what the social and task related consequences of\nthe distribution are. Methodological advances are needed to allow researchers\nto collect data about human robot collaboration that involves multiple people.\nThis paper presents Tower Construction, a novel resource distribution task that\nallows researchers to examine collaboration between a robot and groups of\npeople. By focusing on the question of whether and how a robot's distribution\nof resources (wooden blocks required for a building task) affects collaboration\ndynamics and outcomes, we provide a case of how this task can be applied in a\nlaboratory study with 124 participants to collect data about human robot\ncollaboration that involves multiple humans. We highlight the kinds of insights\nthe task can yield. In particular we find that the distribution of resources\naffects perceptions of performance, and interpersonal dynamics between human\nteam-members.\n",
"title": "Robot Assisted Tower Construction - A Resource Distribution Task to Study Human-Robot Collaboration and Interaction with Groups of People"
}
| null | null |
[
"Computer Science"
] | null | true | null |
5566
| null |
Validated
| null | null |
null |
{
"abstract": " This paper describes three variants of a counterexample guided inductive\noptimization (CEGIO) approach based on Satisfiability Modulo Theories (SMT)\nsolvers. In particular, CEGIO relies on iterative executions to constrain a\nverification procedure, in order to perform inductive generalization, based on\ncounterexamples extracted from SMT solvers. CEGIO is able to successfully\noptimize a wide range of functions, including non-linear and non-convex\noptimization problems based on SMT solvers, in which data provided by\ncounterexamples are employed to guide the verification engine, thus reducing\nthe optimization domain. The present algorithms are evaluated using a large set\nof benchmarks typically employed for evaluating optimization techniques.\nExperimental results show the efficiency and effectiveness of the proposed\nalgorithms, which find the optimal solution in all evaluated benchmarks, while\ntraditional techniques are usually trapped by local minima.\n",
"title": "Counterexample Guided Inductive Optimization"
}
| null | null |
[
"Computer Science"
] | null | true | null |
5567
| null |
Validated
| null | null |
null |
{
"abstract": " In this work, a generalization of pre-Grüss inequality is established.\nSeveral bounds for the difference between two Čebyšev functional are\nproved.\n",
"title": "Bounds for the difference between two Čebyšev functionals"
}
| null | null |
[
"Mathematics"
] | null | true | null |
5568
| null |
Validated
| null | null |
null |
{
"abstract": " An electroencephalography (EEG) based Brain Computer Interface (BCI) enables\npeople to communicate with the outside world by interpreting the EEG signals of\ntheir brains to interact with devices such as wheelchairs and intelligent\nrobots. More specifically, motor imagery EEG (MI-EEG), which reflects a\nsubjects active intent, is attracting increasing attention for a variety of BCI\napplications. Accurate classification of MI-EEG signals while essential for\neffective operation of BCI systems, is challenging due to the significant noise\ninherent in the signals and the lack of informative correlation between the\nsignals and brain activities. In this paper, we propose a novel deep neural\nnetwork based learning framework that affords perceptive insights into the\nrelationship between the MI-EEG data and brain activities. We design a joint\nconvolutional recurrent neural network that simultaneously learns robust\nhigh-level feature presentations through low-dimensional dense embeddings from\nraw MI-EEG signals. We also employ an Autoencoder layer to eliminate various\nartifacts such as background activities. The proposed approach has been\nevaluated extensively on a large- scale public MI-EEG dataset and a limited but\neasy-to-deploy dataset collected in our lab. The results show that our approach\noutperforms a series of baselines and the competitive state-of-the- art\nmethods, yielding a classification accuracy of 95.53%. The applicability of our\nproposed approach is further demonstrated with a practical BCI system for\ntyping.\n",
"title": "Converting Your Thoughts to Texts: Enabling Brain Typing via Deep Feature Learning of EEG Signals"
}
| null | null | null | null | true | null |
5569
| null |
Default
| null | null |
null |
{
"abstract": " On real-time systems running under timing constraints, scheduling can be\nperformed when one is aware of the worst case execution time (WCET) of tasks.\nUsually, the WCET of a task is unknown and schedulers make use of safe\nover-approximations given by static WCET analysis. To reduce the\nover-approximation, WCET analysis has to gain information about the underlying\nhardware behavior, such as pipelines and caches. In this paper, we focus on the\ncache analysis, which classifies memory accesses as hits/misses according to\nthe set of possible cache states. We propose to refine the results of classical\ncache analysis using a model checker, introducing a new cache model for the\nleast recently used (LRU) policy.\n",
"title": "Model Checking of Cache for WCET Analysis Refinement"
}
| null | null |
[
"Computer Science"
] | null | true | null |
5570
| null |
Validated
| null | null |
null |
{
"abstract": " The rational solutions of the Painlevé-II equation appear in several\napplications and are known to have many remarkable algebraic and analytic\nproperties. They also have several different representations, useful in\ndifferent ways for establishing these properties. In particular,\nRiemann-Hilbert representations have proven to be useful for extracting the\nasymptotic behavior of the rational solutions in the limit of large degree\n(equivalently the large-parameter limit). We review the elementary properties\nof the rational Painlevé-II functions, and then we describe three different\nRiemann-Hilbert representations of them that have appeared in the literature: a\nrepresentation by means of the isomonodromy theory of the Flaschka-Newell Lax\npair, a second representation by means of the isomonodromy theory of the\nJimbo-Miwa Lax pair, and a third representation found by Bertola and Bothner\nrelated to pseudo-orthogonal polynomials. We prove that the Flaschka-Newell and\nBertola-Bothner Riemann-Hilbert representations of the rational Painlevé-II\nfunctions are explicitly connected to each other. Finally, we review recent\nresults describing the asymptotic behavior of the rational Painlevé-II\nfunctions obtained from these Riemann-Hilbert representations by means of the\nsteepest descent method.\n",
"title": "Rational Solutions of the Painlevé-II Equation Revisited"
}
| null | null | null | null | true | null |
5571
| null |
Default
| null | null |
null |
{
"abstract": " PHAST is a software package written in standard Fortran, with MPI and CUDA\nextensions, able to efficiently perform parallel multicanonical Monte Carlo\nsimulations of single or multiple heteropolymeric chains, as coarse-grained\nmodels for proteins. The outcome data can be straightforwardly analyzed within\nits microcanonical Statistical Thermodynamics module, which allows for\ncomputing the entropy, caloric curve, specific heat and free energies. As a\ncase study, we investigate the aggregation of heteropolymers bioinspired on\n$A\\beta_{25-33}$ fragments and their cross-seeding with $IAPP_{20-29}$\nisoforms. Excellent parallel scaling is observed, even under numerically\ndifficult first-order like phase transitions, which are properly described by\nthe built-in fully reconfigurable force fields. Still, the package is free and\nopen source, this shall motivate users to readily adapt it to specific\npurposes.\n",
"title": "PHAST: Protein-like heteropolymer analysis by statistical thermodynamics"
}
| null | null |
[
"Physics"
] | null | true | null |
5572
| null |
Validated
| null | null |
null |
{
"abstract": " Information-theoretic Bayesian regret bounds of Russo and Van Roy capture the\ndependence of regret on prior uncertainty. However, this dependence is through\nentropy, which can become arbitrarily large as the number of actions increases.\nWe establish new bounds that depend instead on a notion of rate-distortion.\nAmong other things, this allows us to recover through information-theoretic\narguments a near-optimal bound for the linear bandit. We also offer a bound for\nthe logistic bandit that dramatically improves on the best previously\navailable, though this bound depends on an information-theoretic statistic that\nwe have only been able to quantify via computation.\n",
"title": "An Information-Theoretic Analysis for Thompson Sampling with Many Actions"
}
| null | null | null | null | true | null |
5573
| null |
Default
| null | null |
null |
{
"abstract": " We study a portfolio selection problem in a continuous-time Itô-Markov\nadditive market with prices of financial assets described by Markov additive\nprocesses which combine Lévy processes and regime switching models. Thus the\nmodel takes into account two sources of risk: the jump diffusion risk and the\nregime switching risk. For this reason the market is incomplete. We complete\nthe market by enlarging it with the use of a set of Markovian jump securities,\nMarkovian power-jump securities and impulse regime switching securities.\nMoreover, we give conditions under which the market is\nasymptotic-arbitrage-free. We solve the portfolio selection problem in the\nItô-Markov additive market for the power utility and the logarithmic utility.\n",
"title": "Optimal portfolio selection in an Itô-Markov additive market"
}
| null | null | null | null | true | null |
5574
| null |
Default
| null | null |
null |
{
"abstract": " We present an ongoing, systematic search for extragalactic infrared\ntransients, dubbed SPIRITS --- SPitzer InfraRed Intensive Transients Survey. In\nthe first year, using Spitzer/IRAC, we searched 190 nearby galaxies with\ncadence baselines of one month and six months. We discovered over 1958\nvariables and 43 transients. Here, we describe the survey design and highlight\n14 unusual infrared transients with no optical counterparts to deep limits,\nwhich we refer to as SPRITEs (eSPecially Red Intermediate Luminosity Transient\nEvents). SPRITEs are in the infrared luminosity gap between novae and\nsupernovae, with [4.5] absolute magnitudes between -11 and -14 (Vega-mag) and\n[3.6]-[4.5] colors between 0.3 mag and 1.6 mag. The photometric evolution of\nSPRITEs is diverse, ranging from < 0.1 mag/yr to > 7 mag/yr. SPRITEs occur in\nstar-forming galaxies. We present an in-depth study of one of them, SPIRITS\n14ajc in Messier 83, which shows shock-excited molecular hydrogen emission.\nThis shock may have been triggered by the dynamic decay of a non-hierarchical\nsystem of massive stars that led to either the formation of a binary or a\nproto-stellar merger.\n",
"title": "SPIRITS: Uncovering Unusual Infrared Transients With Spitzer"
}
| null | null | null | null | true | null |
5575
| null |
Default
| null | null |
null |
{
"abstract": " We describe the Time Series Multivariate Adaptive Regressions Splines\n(TSMARS) method. This method is useful for identifying nonlinear structure in a\ntime series. We use TSMARS to model the annual change in the balance of trade\nfor Ireland from 1970 to 2007. We compare the TSMARS estimate with long memory\nARFIMA estimates and long-term parsimonious linear models. We show that the\nchange in the balance of trade is nonlinear and possesses weakly long range\neffects. Moreover, we compare the period prior to the introduction of the\nIntrastat system in 1993 with the period from 1993 onward. Here we show that in\nthe earlier period the series had a substantial linear signal embedded in it\nsuggesting that estimation efforts in the earlier period may have resulted in\nan over-smoothed series.\n",
"title": "Is the annual growth rate in balance of trade time series for Ireland nonlinear"
}
| null | null | null | null | true | null |
5576
| null |
Default
| null | null |
null |
{
"abstract": " A major challenge in X-ray computed tomography (CT) is reducing radiation\ndose while maintaining high quality of reconstructed images. To reduce the\nradiation dose, one can reduce the number of projection views (sparse-view CT);\nhowever, it becomes difficult to achieve high quality image reconstruction as\nthe number of projection views decreases. Researchers have applied the concept\nof learning sparse representations from (high-quality) CT image dataset to the\nsparse-view CT reconstruction. We propose a new statistical CT reconstruction\nmodel that combines penalized weighted-least squares (PWLS) and $\\ell_1$\nregularization with learned sparsifying transform (PWLS-ST-$\\ell_1$), and an\nalgorithm for PWLS-ST-$\\ell_1$. Numerical experiments for sparse-view 2D\nfan-beam CT and 3D axial cone-beam CT show that the $\\ell_1$ regularizer\nsignificantly improves the sharpness of edges of reconstructed images compared\nto the CT reconstruction methods using edge-preserving regularizer and $\\ell_2$\nregularization with learned ST.\n",
"title": "Sparse-View X-Ray CT Reconstruction Using $\\ell_1$ Prior with Learned Transform"
}
| null | null | null | null | true | null |
5577
| null |
Default
| null | null |
null |
{
"abstract": " Classification problems in security settings are usually contemplated as\nconfrontations in which one or more adversaries try to fool a classifier to\nobtain a benefit. Most approaches to such adversarial classification problems\nhave focused on game theoretical ideas with strong underlying common knowledge\nassumptions, which are actually not realistic in security domains. We provide\nan alternative framework to such problem based on adversarial risk analysis,\nwhich we illustrate with several examples. Computational and implementation\nissues are discussed.\n",
"title": "Adversarial classification: An adversarial risk analysis approach"
}
| null | null | null | null | true | null |
5578
| null |
Default
| null | null |
null |
{
"abstract": " For a Liouville domain $W$ whose boundary admits a periodic Reeb flow, we can\nconsider the connected component $[\\tau] \\in \\pi_0(\\text{Symp}^c(\\widehat W))$\nof fibered twists. In this paper, we investigate an entropy-type invariant,\ncalled the slow volume growth, of the component $[\\tau]$ and give a uniform\nlower bound of the growth using wrapped Floer homology. We also show that\n$[\\tau]$ has infinite order in $\\pi_0(\\text{Symp}^c(\\widehat W))$ if there is\nan admissible Lagrangian $L$ in $W$ whose wrapped Floer homology is infinite\ndimensional. We apply our results to fibered twists coming from the Milnor\nfibers of $A_k$-type singularities and complements of a symplectic hypersurface\nin a real symplectic manifold. They admit so-called real Lagrangians, and we\ncan explicitly compute wrapped Floer homology groups using a version of\nMorse-Bott spectral sequences.\n",
"title": "Volume growth in the component of fibered twists"
}
| null | null | null | null | true | null |
5579
| null |
Default
| null | null |
null |
{
"abstract": " We study a deterministic version of a one- and two-dimensional attractor\nneural network model of hippocampal activity first studied by Itskov et al\n2011. We analyze the dynamics of the system on the ring and torus domain with\nan even periodized weight matrix, assum- ing weak and slow spike frequency\nadaptation and a weak stationary input current. On these domains, we find\ntransitions from spatially localized stationary solutions (\"bumps\") to\n(periodically modulated) solutions (\"sloshers\"), as well as constant and\nnon-constant velocity traveling bumps depending on the relative strength of\nexternal input current and adaptation. The weak and slow adaptation allows for\na reduction of the system from a distributed partial integro-differential\nequation to a system of scalar Volterra integro-differential equations\ndescribing the movement of the centroid of the bump solution. Using this\nreduction, we show that on both domains, sloshing solutions arise through an\nAndronov-Hopf bifurcation and derive a normal form for the Hopf bifurcation on\nthe ring. We also show existence and stability of constant velocity solutions\non both domains using Evans functions. In contrast to existing studies, we\nassume a general weight matrix of Mexican-hat type in addition to a smooth\nfiring rate function.\n",
"title": "Scalar Reduction of a Neural Field Model with Spike Frequency Adaptation"
}
| null | null | null | null | true | null |
5580
| null |
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| null | null |
null |
{
"abstract": " Operational semantics have been enormously successful, in large part due to\nits flexibility and simplicity, but they are not compositional. Denotational\nsemantics, on the other hand, are compositional but the lattice-theoretic\nmodels are complex and difficult to scale to large languages. However, there\nare elementary models of the $\\lambda$-calculus that are much less complex: by\nCoppo, Dezani-Ciancaglini, and Salle (1979), Engeler (1981), and Plotkin\n(1993).\nThis paper takes first steps toward answering the question: can elementary\nmodels be good for the day-to-day work of language specification,\nmechanization, and compiler correctness? The elementary models in the\nliterature are simple, but they are not as intuitive as they could be. To\nremedy this, we create a new model that represents functions literally as\nfinite graphs. Regarding mechanization, we give the first machine-checked proof\nof soundness and completeness of an elementary model with respect to an\noperational semantics. Regarding compiler correctness, we define a polyvariant\ninliner for the call-by-value $\\lambda$-calculus and prove that its output is\ncontextually equivalent to its input. Toward scaling elementary models to\nlarger languages, we formulate our semantics in a monadic style, give a\nsemantics for System F with general recursion, and mechanize the proof of type\nsoundness.\n",
"title": "Revisiting Elementary Denotational Semantics"
}
| null | null | null | null | true | null |
5581
| null |
Default
| null | null |
null |
{
"abstract": " The particle-hole (PH) symmetry at half-filled Landau level requires the\nrelationship between the flux number N_phi and the particle number N on a\nsphere to be exactly N_phi - 2(N-1) = 1. The wave functions of composite\nfermions with 1/2 \"orbital spin\", which contributes to the shift \"1\" in the\nN_phi and N relationship, are proposed, shown to be PH symmetric, and validated\nwith exact finite system results. It is shown the many-body composite electron\nand composite hole wave functions at half-filling can be formed from the two\ncomponents of the same spinor wave function of a massless Dirac fermion at\nzero-magnetic field. It is further shown that away from half-filling, the\nmany-body composite electron wave function at filling factor nu and its PH\nconjugated composite hole wave function at 1-nu can be formed from the two\ncomponents of the very same spinor wave functions of a massless Dirac fermion\nat non-zero magnetic field. This relationship leads to the proposal of a very\nsimple Dirac composite fermion effective field theory, where the two-component\nDirac fermion field is a particle-hole spinor field coupled to the same\nemergent gauge field, with one field component describing the composite\nelectrons and the other describing the PH conjugated composite holes. As such,\nthe density of the Dirac spinor field is the density sum of the composite\nelectron and hole field components, and therefore is equal to the degeneracy of\nthe Lowest Landau level. On the other hand, the charge density coupled to the\nexternal magnetic field is the density difference between the composite\nelectron and hole field components, and is therefore neutral at exactly\nhalf-filling. It is shown that the proposed particle-hole spinor effective\nfield theory gives essentially the same electromagnetic responses as Son's\nDirac composite fermion theory does.\n",
"title": "Dirac Composite Fermion - A Particle-Hole Spinor"
}
| null | null | null | null | true | null |
5582
| null |
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| null | null |
null |
{
"abstract": " Importance sampling has become an indispensable strategy to speed up\noptimization algorithms for large-scale applications. Improved adaptive\nvariants - using importance values defined by the complete gradient information\nwhich changes during optimization - enjoy favorable theoretical properties, but\nare typically computationally infeasible. In this paper we propose an efficient\napproximation of gradient-based sampling, which is based on safe bounds on the\ngradient. The proposed sampling distribution is (i) provably the best sampling\nwith respect to the given bounds, (ii) always better than uniform sampling and\nfixed importance sampling and (iii) can efficiently be computed - in many\napplications at negligible extra cost. The proposed sampling scheme is generic\nand can easily be integrated into existing algorithms. In particular, we show\nthat coordinate-descent (CD) and stochastic gradient descent (SGD) can enjoy\nsignificant a speed-up under the novel scheme. The proven efficiency of the\nproposed sampling is verified by extensive numerical testing.\n",
"title": "Safe Adaptive Importance Sampling"
}
| null | null | null | null | true | null |
5583
| null |
Default
| null | null |
null |
{
"abstract": " We consider a problem, which we call secure grouping, of dividing a number of\nparties into some subsets (groups) in the following manner: Each party has to\nknow the other members of his/her group, while he/she may not know anything\nabout how the remaining parties are divided (except for certain public\npredetermined constraints, such as the number of parties in each group). In\nthis paper, we construct an information-theoretically secure protocol using a\ndeck of physical cards to solve the problem, which is jointly executable by the\nparties themselves without a trusted third party. Despite the non-triviality\nand the potential usefulness of the secure grouping, our proposed protocol is\nfairly simple to describe and execute. Our protocol is based on algebraic\nproperties of conjugate permutations. A key ingredient of our protocol is our\nnew techniques to apply multiplication and inverse operations to hidden\npermutations (i.e., those encoded by using face-down cards), which would be of\nindependent interest and would have various potential applications.\n",
"title": "Secure Grouping Protocol Using a Deck of Cards"
}
| null | null | null | null | true | null |
5584
| null |
Default
| null | null |
null |
{
"abstract": " Let $\\mathcal C$ be a subcategory of the category of topologized semigroups\nand their partial continuous homomorphisms. An object $X$ of the category\n${\\mathcal C}$ is called ${\\mathcal C}$-closed if for each morphism $f:X\\to Y$\nof the category ${\\mathcal C}$ the image $f(X)$ is closed in $Y$. In the paper\nwe detect topological groups which are $\\mathcal C$-closed for the categories\n$\\mathcal C$ whose objects are Hausdorff topological (semi)groups and whose\nmorphisms are isomorphic topological embeddings, injective continuous\nhomomorphisms, continuous homomorphisms, or partial continuous homomorphisms\nwith closed domain.\n",
"title": "Categorically closed topological groups"
}
| null | null | null | null | true | null |
5585
| null |
Default
| null | null |
null |
{
"abstract": " According to the Eurobarometer report about EU media use of May 2018, the\nnumber of European citizens who consult on-line social networks for accessing\ninformation is considerably increasing. In this work we analyze approximately\n$10^6$ tweets exchanged during the last Italian elections. By using an\nentropy-based null model discounting the activity of the users, we first\nidentify potential political alliances within the group of verified accounts:\nif two verified users are retweeted more than expected by the non-verified\nones, they are likely to be related. Then, we derive the users' affiliation to\na coalition measuring the polarization of unverified accounts. Finally, we\nstudy the bipartite directed representation of the tweets and retweets network,\nin which tweets and users are collected on the two layers. Users with the\nhighest out-degree identify the most popular ones, whereas highest out-degree\nposts are the most \"viral\". We identify significant content spreaders by\nstatistically validating the connections that cannot be explained by users'\ntweeting activity and posts' virality by using an entropy-based null model as\nbenchmark. The analysis of the directed network of validated retweets reveals\nsignals of the alliances formed after the elections, highlighting commonalities\nof interests before the event of the national elections.\n",
"title": "Extracting significant signal of news consumption from social networks: the case of Twitter in Italian political elections"
}
| null | null | null | null | true | null |
5586
| null |
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| null | null |
null |
{
"abstract": " We introduce a novel framework for adversarial training where the target\ndistribution is annealed between the uniform distribution and the data\ndistribution. We posited a conjecture that learning under continuous annealing\nin the nonparametric regime is stable irrespective of the divergence measures\nin the objective function and proposed an algorithm, dubbed {\\ss}-GAN, in\ncorollary. In this framework, the fact that the initial support of the\ngenerative network is the whole ambient space combined with annealing are key\nto balancing the minimax game. In our experiments on synthetic data, MNIST, and\nCelebA, {\\ss}-GAN with a fixed annealing schedule was stable and did not suffer\nfrom mode collapse.\n",
"title": "Annealed Generative Adversarial Networks"
}
| null | null | null | null | true | null |
5587
| null |
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| null | null |
null |
{
"abstract": " This paper considers the problem of achieving attitude consensus in\nspacecraft formations with bounded, time-varying communication delays between\nspacecraft connected as specified by a strongly connected topology. A state\nfeedback con- troller is proposed and investigated using a time domain approach\n(via LMIs) and a frequency domain approach (via the small-gain theorem) to\nobtain delay depen- dent stability criteria to achieve the desired consensus.\nSimulations are presented to demonstrate the application of the strategy in a\nspecific scenario.\n",
"title": "Attitude Control of Spacecraft Formations Subject To Distributed Communication Delays"
}
| null | null | null | null | true | null |
5588
| null |
Default
| null | null |
null |
{
"abstract": " The analysis of clouds in the earth's atmosphere is important for a variety\nof applications, viz. weather reporting, climate forecasting, and solar energy\ngeneration. In this paper, we focus our attention on the impact of cloud on the\ntotal solar irradiance reaching the earth's surface. We use weather station to\nrecord the total solar irradiance. Moreover, we employ collocated ground-based\nsky camera to automatically compute the instantaneous cloud coverage. We\nanalyze the relationship between measured solar irradiance and computed cloud\ncoverage value, and conclude that higher cloud coverage greatly impacts the\ntotal solar irradiance. Such studies will immensely help in solar energy\ngeneration and forecasting.\n",
"title": "Cloud Radiative Effect Study Using Sky Camera"
}
| null | null | null | null | true | null |
5589
| null |
Default
| null | null |
null |
{
"abstract": " Nowadays, we are witnessing a wide adoption of Machine learning (ML) models\nin many safety-critical systems, thanks to recent breakthroughs in deep\nlearning and reinforcement learning. Many people are now interacting with\nsystems based on ML every day, e.g., voice recognition systems used by virtual\npersonal assistants like Amazon Alexa or Google Home. As the field of ML\ncontinues to grow, we are likely to witness transformative advances in a wide\nrange of areas, from finance, energy, to health and transportation. Given this\ngrowing importance of ML-based systems in our daily life, it is becoming\nutterly important to ensure their reliability. Recently, software researchers\nhave started adapting concepts from the software testing domain (e.g., code\ncoverage, mutation testing, or property-based testing) to help ML engineers\ndetect and correct faults in ML programs. This paper reviews current existing\ntesting practices for ML programs. First, we identify and explain challenges\nthat should be addressed when testing ML programs. Next, we report existing\nsolutions found in the literature for testing ML programs. Finally, we identify\ngaps in the literature related to the testing of ML programs and make\nrecommendations of future research directions for the scientific community. We\nhope that this comprehensive review of software testing practices will help ML\nengineers identify the right approach to improve the reliability of their\nML-based systems. We also hope that the research community will act on our\nproposed research directions to advance the state of the art of testing for ML\nprograms.\n",
"title": "On Testing Machine Learning Programs"
}
| null | null | null | null | true | null |
5590
| null |
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| null | null |
null |
{
"abstract": " The theory of statistical inference along with the strategy of\ndivide-and-conquer for large- scale data analysis has recently attracted\nconsiderable interest due to great popularity of the MapReduce programming\nparadigm in the Apache Hadoop software framework. The central analytic task in\nthe development of statistical inference in the MapReduce paradigm pertains to\nthe method of combining results yielded from separately mapped data batches.\nOne seminal solution based on the confidence distribution has recently been\nestablished in the setting of maximum likelihood estimation in the literature.\nThis paper concerns a more general inferential methodology based on estimating\nfunctions, termed as the Rao-type confidence distribution, of which the maximum\nlikelihood is a special case. This generalization provides a unified framework\nof statistical inference that allows regression analyses of massive data sets\nof important types in a parallel and scalable fashion via a distributed file\nsystem, including longitudinal data analysis, survival data analysis, and\nquantile regression, which cannot be handled using the maximum likelihood\nmethod. This paper investigates four important properties of the proposed\nmethod: computational scalability, statistical optimality, methodological\ngenerality, and operational robustness. In particular, the proposed method is\nshown to be closely connected to Hansen's generalized method of moments (GMM)\nand Crowder's optimality. An interesting theoretical finding is that the\nasymptotic efficiency of the proposed Rao-type confidence distribution\nestimator is always greater or equal to the estimator obtained by processing\nthe full data once. All these properties of the proposed method are illustrated\nvia numerical examples in both simulation studies and real-world data analyses.\n",
"title": "Scalable and Efficient Statistical Inference with Estimating Functions in the MapReduce Paradigm for Big Data"
}
| null | null | null | null | true | null |
5591
| null |
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| null | null |
null |
{
"abstract": " In a scalar reaction-diffusion equation, it is known that the stability of a\nsteady state can be determined from the Maslov index, a topological invariant\nthat counts the state's critical points. In particular, this implies that pulse\nsolutions are unstable. We extend this picture to pulses in reaction-diffusion\nsystems with gradient nonlinearity. In particular, we associate a Maslov index\nto any asymptotically constant state, generalizing existing definitions of the\nMaslov index for homoclinic orbits. It is shown that this index equals the\nnumber of unstable eigenvalues for the linearized evolution equation. Finally,\nwe use a symmetry argument to show that any pulse solution must have nonzero\nMaslov index, and hence be unstable.\n",
"title": "Instability of pulses in gradient reaction-diffusion systems: A symplectic approach"
}
| null | null | null | null | true | null |
5592
| null |
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| null | null |
null |
{
"abstract": " New results on functional prediction of the Ornstein-Uhlenbeck process in an\nautoregressive Hilbert-valued and Banach-valued frameworks are derived.\nSpecifically, consistency of the maximum likelihood estimator of the\nautocorrelation operator, and of the associated plug-in predictor is obtained\nin both frameworks.\n",
"title": "Consistency of the plug-in functional predictor of the Ornstein-Uhlenbeck process in Hilbert and Banach spaces"
}
| null | null | null | null | true | null |
5593
| null |
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| null | null |
null |
{
"abstract": " The goal of this dissertation is to study the sequence polymorphism in\nretrotransposable elements of Entamoeba histolytica. The Quasispecies theory, a\nconcept of equilibrium (stationary), has been used to understand the behaviour\nof these elements. Two datasets of retrotransposons of Entamoeba histolytica\nhave been used. We present results from both datasets of retrotransposons\n(SINE1s) of E. histolytica. We have calculated the mutation rate of EhSINE1s\nfor both datasets and drawn a phylogenetic tree for newly determined EhSINE1s\n(dataset II). We have also discussed the variation in lengths of EhSINE1s for\nboth datasets. Using the quasispecies model, we have shown how sequences of\nSINE1s vary within the population. The outputs of the quasispecies model are\ndiscussed in the presence and the absence of back mutation by taking different\nvalues of fitness. From our study of Non-long terminal repeat retrotransposons\n(LINEs and their non-autonomous partner's SINEs) of Entamoeba histolytica, we\ncan conclude that an active EhSINE can generate very similar copies of itself\nby retrotransposition. Due to this reason, it increases mutations which give\nthe result of sequence polymorphism. We have concluded that the mutation rate\nof SINE is very high. This high mutation rate provides an idea for the\nexistence of SINEs, which may affect the genetic analysis of EhSINE1\nancestries, and calculation of phylogenetic distances.\n",
"title": "Analysis of Sequence Polymorphism of LINEs and SINEs in Entamoeba histolytica"
}
| null | null | null | null | true | null |
5594
| null |
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| null | null |
null |
{
"abstract": " It is known that connected translation invariant $n$-dimensional\nnoncommutative differentials $d x^i$ on the algebra $k[x^1,\\cdots,x^n]$ of\npolynomials in $n$-variables over a field $k$ are classified by commutative\nalgebras $V$ on the vector space spanned by the coordinates. This data also\napplies to construct differentials on the Heisenberg algebra `spacetime' with\nrelations $[x^\\mu,x^\\nu]=\\lambda\\Theta^{\\mu\\nu}$ where $ \\Theta$ is an\nantisymmetric matrix as well as to Lie algebras with pre-Lie algebra\nstructures. We specialise the general theory to the field $k={\\ \\mathbb{F}}_2$\nof two elements, in which case translation invariant metrics (i.e. with\nconstant coefficients) are equivalent to making $V$ a Frobenius algebras. We\nclassify all of these and their quantum Levi-Civita bimodule connections for\n$n=2,3$, with partial results for $n=4$. For $n=2$ we find 3 inequivalent\ndifferential structures admitting 1,2 and 3 invariant metrics respectively. For\n$n=3$ we find 6 differential structures admitting $0,1,2,3,4,7$ invariant\nmetrics respectively. We give some examples for $n=4$ and general $n$.\nSurprisingly, not all our geometries for $n\\ge 2$ have zero quantum Riemann\ncurvature. Quantum gravity is normally seen as a weighted `sum' over all\npossible metrics but our results are a step towards a deeper approach in which\nwe must also `sum' over differential structures. Over ${\\mathbb{F}}_2$ we\nconstruct some of our algebras and associated structures by digital gates,\nopening up the possibility of `digital geometry'.\n",
"title": "Classification of digital affine noncommutative geometries"
}
| null | null | null | null | true | null |
5595
| null |
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| null | null |
null |
{
"abstract": " We obtain a reduction of the vectorial Ribaucour transformation that\npreserves the class of submanifolds of constant sectional curvature of space\nforms, which we call the $L$-transformation. It allows to construct a family of\nsuch submanifolds starting with a given one and a vector-valued solution of a\nsystem of linear partial differential equations. We prove a decomposition\ntheorem for the $L$-transformation, which is a far-reaching generalization of\nthe classical permutability formula for the Ribaucour transformation of\nsurfaces of constant curvature in Euclidean three space. As a consequence, we\nderive a Bianchi-cube theorem, which allows to produce, from $k$ initial scalar\n$L$-transforms of a given submanifold of constant curvature, a whole\n$k$-dimensional cube all of whose remaining $2^k-(k+1)$ vertices are\nsubmanifolds with the same constant sectional curvature given by explicit\nalgebraic formulae. We also obtain further reductions, as well as corresponding\ndecomposition and Bianchi-cube theorems, for the classes of $n$-dimensional\nflat Lagrangian submanifolds of $\\mathbb{C}^n$ and $n$-dimensional Lagrangian\nsubmanifolds with constant curvature $c$ of the complex projective space\n$\\mathbb C\\mathbb P^n(4c)$ or the complex hyperbolic space $\\mathbb C\\mathbb\nH^n(4c)$ of complex dimension $n$ and constant holomorphic curvature~4c.\n",
"title": "The vectorial Ribaucour transformation for submanifolds of constant sectional curvature"
}
| null | null | null | null | true | null |
5596
| null |
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| null | null |
null |
{
"abstract": " Human relations are driven by social events - people interact, exchange\ninformation, share knowledge and emotions, or gather news from mass media.\nThese events leave traces in human memory. The initial strength of a trace\ndepends on cognitive factors such as emotions or attention span. Each trace\ncontinuously weakens over time unless another related event activity\nstrengthens it. Here, we introduce a novel Cognition-driven Social Network\n(CogSNet) model that accounts for cognitive aspects of social perception and\nexplicitly represents human memory dynamics. For validation, we apply our model\nto NetSense data on social interactions among university students. The results\nshow that CogSNet significantly improves quality of modeling of human\ninteractions in social networks.\n",
"title": "Social Networks through the Prism of Cognition"
}
| null | null |
[
"Computer Science"
] | null | true | null |
5597
| null |
Validated
| null | null |
null |
{
"abstract": " We present a novel framework for addressing the nonlinear Landau collision\nintegral in terms of finite element and other subspace projection methods. We\nemploy the underlying metriplectic structure of the Landau collision integral\nand, using a Galerkin discretization for the velocity space, we transform the\ninfinite-dimensional system into a finite-dimensional, time-continuous\nmetriplectic system. Temporal discretization is accomplished using the concept\nof discrete gradients. The conservation of energy, momentum, and particle\ndensities, as well as the production of entropy is demonstrated algebraically\nfor the fully discrete system. Due to the generality of our approach, the\nconservation properties and the monotonic behavior of entropy are guaranteed\nfor finite element discretizations in general, independently of the mesh\nconfiguration.\n",
"title": "Metriplectic Integrators for the Landau Collision Operator"
}
| null | null | null | null | true | null |
5598
| null |
Default
| null | null |
null |
{
"abstract": " The $r$-fold analogues of Whitney trick were `in the air' since 1960s.\nHowever, only in this century they were stated, proved and applied to obtain\ninteresting results, most notably by Mabillard and Wagner. Here we prove and\napply a version of the $r$-fold Whitney trick when general position $r$-tuple\nintersections have positive dimension.\nTheorem. Assume that $D=D_1\\sqcup\\ldots\\sqcup D_r$ is disjoint union of\n$k$-dimensional disks, $rd\\ge (r+1)k+3$, and $f:D\\to B^d$ a proper PL (smooth)\nmap such that $f\\partial D_1\\cap\\ldots\\cap f\\partial D_r=\\emptyset$. If the map\n$$f^r:\\partial(D_1\\times\\ldots\\times D_r)\\to\n(B^d)^r-\\{(x,x,\\ldots,x)\\in(B^d)^r\\ |\\ x\\in B^d\\}$$ extends to\n$D_1\\times\\ldots\\times D_r$, then there is a proper PL (smooth) map $\\overline\nf:D\\to B^d$ such that $\\overline f=f$ on $\\partial D$ and $\\overline\nfD_1\\cap\\ldots\\cap \\overline fD_r=\\emptyset$.\n",
"title": "Eliminating higher-multiplicity intersections in the metastable dimension range"
}
| null | null | null | null | true | null |
5599
| null |
Default
| null | null |
null |
{
"abstract": " A material-based, i.e., Lagrangian, methodology for exact integration of flux\nby volume-preserving flows through a surface has been developed recently in\n[Karrasch, SIAM J. Appl. Math., 76 (2016), pp. 1178-1190]. In the present\npaper, we first generalize this framework to general compressible flows,\nthereby solving the donating region problem in full generality. Second, we\ndemonstrate the efficacy of this approach on a slightly idealized version of a\nclassic two-dimensional mixing problem: transport in a cross-channel\nmicromixer, as considered recently in [Balasuriya, SIAM J. Appl. Dyn. Syst., 16\n(2017), pp. 1015-1044].\n",
"title": "Lagrangian Transport Through Surfaces in Compressible Flows"
}
| null | null | null | null | true | null |
5600
| null |
Default
| null | null |
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