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null | inputs
dict | prediction
null | prediction_agent
null | annotation
list | annotation_agent
null | multi_label
bool 1
class | explanation
null | id
stringlengths 1
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{
"abstract": " Providing systems the ability to relate linguistic and visual content is one\nof the hallmarks of computer vision. Tasks such as image captioning and\nretrieval were designed to test this ability, but come with complex evaluation\nmeasures that gauge various other abilities and biases simultaneously. This\npaper presents an alternative evaluation task for visual-grounding systems:\ngiven a caption the system is asked to select the image that best matches the\ncaption from a pair of semantically similar images. The system's accuracy on\nthis Binary Image SelectiON (BISON) task is not only interpretable, but also\nmeasures the ability to relate fine-grained text content in the caption to\nvisual content in the images. We gathered a BISON dataset that complements the\nCOCO Captions dataset and used this dataset in auxiliary evaluations of\ncaptioning and caption-based retrieval systems. While captioning measures\nsuggest visual grounding systems outperform humans, BISON shows that these\nsystems are still far away from human performance.\n",
"title": "Binary Image Selection (BISON): Interpretable Evaluation of Visual Grounding"
}
| null | null | null | null | true | null |
11201
| null |
Default
| null | null |
null |
{
"abstract": " In this paper we study the limitations of parallelization in convex\noptimization. A convenient approach to study parallelization is through the\nprism of \\emph{adaptivity} which is an information theoretic measure of the\nparallel runtime of an algorithm. Informally, adaptivity is the number of\nsequential rounds an algorithm needs to make when it can execute\npolynomially-many queries in parallel at every round. For combinatorial\noptimization with black-box oracle access, the study of adaptivity has recently\nled to exponential accelerations in parallel runtime and the natural question\nis whether dramatic accelerations are achievable for convex optimization.\nOur main result is a spoiler. We show that, in general, parallelization does\nnot accelerate convex optimization. In particular, for the problem of\nminimizing a non-smooth Lipschitz and strongly convex function with black-box\noracle access we give information theoretic lower bounds that indicate that the\nnumber of adaptive rounds of any randomized algorithm exactly match the upper\nbounds of single-query-per-round (i.e. non-parallel) algorithms.\n",
"title": "Parallelization does not Accelerate Convex Optimization: Adaptivity Lower Bounds for Non-smooth Convex Minimization"
}
| null | null | null | null | true | null |
11202
| null |
Default
| null | null |
null |
{
"abstract": " Applying the principle of equivalence, analogous to Einstein's original 1907\napproach demonstrating the bending of light in a gravitational field, we deduce\nthat radial geodesics of point masses are velocity dependent. Then, using the\nSchwarzschild solution for observers at spatial infinity, we analyze the\nsimilar case of masses moving on timelike geodesics, rederiving a previous\nresult by Hilbert from 1917. We find that the Schwarzschild solution gives more\nthan twice the rate of falling than found from the simpler acceleration\narguments in flat space. We note Einstein also found a similar difference for\nthe bending of light between these two approaches and in this case the\nincreased deflection of light was due to space curvature. Similarly we find\nthat in our case, the discrepancy between the two approaches can be attributed\nto space curvature. Although we have calculated the effect locally for\nobservers under a Schwarzschild coordinate system in a weak field, further work\nneeds to be carried out to explore the stronger field case.\n",
"title": "Velocity dependence of point masses, moving on timelike geodesics, in weak gravitational fields"
}
| null | null | null | null | true | null |
11203
| null |
Default
| null | null |
null |
{
"abstract": " In Demand Response programs, price incentives might not be sufficient to\nmodify residential consumers load profile. Here, we consider that each consumer\nhas a preferred profile and a discomfort cost when deviating from it. Consumers\ncan value this discomfort at a varying level that we take as a parameter. This\nwork analyses Demand Response as a game theoretic environment. We study the\nequilibria of the game between consumers with preferences within two different\ndynamic pricing mechanisms, respectively the daily proportional mechanism\nintroduced by Mohsenian-Rad et al, and an hourly proportional mechanism. We\ngive new results about equilibria as functions of the preference level in the\ncase of quadratic system costs and prove that, whatever the preference level,\nsystem costs are smaller with the hourly mechanism. We simulate the Demand\nResponse environment using real consumption data from PecanStreet database.\nWhile the Price of Anarchy remains always close to one up to 0.1% with the\nhourly mechanism, it can be more than 10% bigger with the daily mechanism.\n",
"title": "Demand Response in the Smart Grid: the Impact of Consumers Temporal Preferences"
}
| null | null | null | null | true | null |
11204
| null |
Default
| null | null |
null |
{
"abstract": " In this letter, we introduce a distributed Nesterov method, termed as\n$\\mathcal{ABN}$, that does not require doubly-stochastic weight matrices.\nInstead, the implementation is based on a simultaneous application of both row-\nand column-stochastic weights that makes this method applicable to arbitrary\n(strongly-connected) graphs. Since constructing column-stochastic weights needs\nadditional information (the number of outgoing neighbors at each agent), not\navailable in certain communication protocols, we derive a variation, termed as\nFROZEN, that only requires row-stochastic weights but at the expense of\nadditional iterations for eigenvector learning. We numerically study these\nalgorithms for various objective functions and network parameters and show that\nthe proposed distributed Nesterov methods achieve acceleration compared to the\ncurrent state-of-the-art methods for distributed optimization.\n",
"title": "Distributed Nesterov gradient methods over arbitrary graphs"
}
| null | null | null | null | true | null |
11205
| null |
Default
| null | null |
null |
{
"abstract": " One of the most important features of mobile rescue robots is the ability to\nautonomously detect casualties, i.e. human bodies, which are usually lying on\nthe ground. This paper proposes a novel method for autonomously detecting\ncasualties lying on the ground using obtained 3D point-cloud data from an\non-board sensor, such as an RGB-D camera or a 3D LIDAR, on a mobile rescue\nrobot. In this method, the obtained 3D point-cloud data is projected onto the\ndetected ground plane, i.e. floor, within the point cloud. Then, this projected\npoint cloud is converted into a grid-map that is used afterwards as an input\nfor the algorithm to detect human body shapes. The proposed method is evaluated\nby performing detection of a human dummy, placed in different random positions\nand orientations, using an on-board RGB-D camera on a mobile rescue robot\ncalled ResQbot. To evaluate the robustness of the casualty detection method to\ndifferent camera angles, the orientation of the camera is set to different\nangles. The experimental results show that using the point-cloud data from the\non-board RGB-D camera, the proposed method successfully detects the casualty in\nall tested body positions and orientations relative to the on-board camera, as\nwell as in all tested camera angles.\n",
"title": "Casualty Detection from 3D Point Cloud Data for Autonomous Ground Mobile Rescue Robots"
}
| null | null | null | null | true | null |
11206
| null |
Default
| null | null |
null |
{
"abstract": " It is well known that the normaized characters of integrable highest weight\nmodules of given level over an affine Lie algebra $\\hat{\\frak{g}}$ span an\n$SL_2(\\mathbf{Z})$-invariant space. This result extends to admissible\n$\\hat{\\frak{g}}$-modules, where $\\frak{g}$ is a simple Lie algebra or\n$osp_{1|n}$. Applying the quantum Hamiltonian reduction (QHR) to admissible\n$\\hat{\\frak{g}}$-modules when $\\frak{g} =sl_2$ (resp. $=osp_{1|2}$) one obtains\nminimal series modules over the Virasoro (resp. $N=1$ superconformal algebras),\nwhich form modular invariant families.\nAnother instance of modular invariance occurs for boundary level admissible\nmodules, including when $\\frak{g}$ is a basic Lie superalgebra. For example, if\n$\\frak{g}=sl_{2|1}$ (resp. $=osp_{3|2}$), we thus obtain modular invariant\nfamilies of $\\hat{\\frak{g}}$-modules, whose QHR produces the minimal series\nmodules for the $N=2$ superconformal algebras (resp. a modular invariant family\nof $N=3$ superconformal algebra modules).\nHowever, in the case when $\\frak{g}$ is a basic Lie superalgebra different\nfrom a simple Lie algebra or $osp_{1|n}$, modular invariance of normalized\nsupercharacters of admissible $\\hat{\\frak{g}}$-modules holds outside of\nboundary levels only after their modification in the spirit of Zwegers'\nmodification of mock theta functions. Applying the QHR, we obtain families of\nrepresentations of $N=2,3,4$ and big $N=4$ superconformal algebras, whose\nmodified (super)characters span an $SL_2(\\mathbf{Z})$-invariant space.\n",
"title": "Representations of superconformal algebras and mock theta functions"
}
| null | null | null | null | true | null |
11207
| null |
Default
| null | null |
null |
{
"abstract": " To solve the spectrum scarcity problem, the cognitive radio technology\ninvolves licensed users and unlicensed users. A fundamental issue for the\nnetwork users is whether it is better to act as a licensed user by using a\nprimary network or an unlicensed user by using a secondary network. To model\nthe network selection process by the users, the deterministic replicator\ndynamics is often used, but in a less practical way that it requires each user\nto know global information on the network state for reaching a Nash\nequilibrium. This paper addresses the network selection process in a more\npractical way such that only noise-prone estimation of local information is\nrequired and, yet, it obtains an efficient system performance.\n",
"title": "Anchored Network Users: Stochastic Evolutionary Dynamics of Cognitive Radio Network Selection"
}
| null | null | null | null | true | null |
11208
| null |
Default
| null | null |
null |
{
"abstract": " The growing interest for high dimensional and functional data analysis led in\nthe last decade to an important research developing a consequent amount of\ntechniques. Parallelized algorithms, which consist in distributing and treat\nthe data into different machines, for example, are a good answer to deal with\nlarge samples taking values in high dimensional spaces. We introduce here a\nparallelized averaged stochastic gradient algorithm, which enables to treat\nefficiently and recursively the data, and so, without taking care if the\ndistribution of the data into the machines is uniform. The rate of convergence\nin quadratic mean as well as the asymptotic normality of the parallelized\nestimates are given, for strongly and locally strongly convex objectives.\n",
"title": "On the rates of convergence of Parallelized Averaged Stochastic Gradient Algorithms"
}
| null | null |
[
"Mathematics",
"Statistics"
] | null | true | null |
11209
| null |
Validated
| null | null |
null |
{
"abstract": " Extended Dynamic Mode Decomposition (EDMD) is an algorithm that approximates\nthe action of the Koopman operator on an $N$-dimensional subspace of the space\nof observables by sampling at $M$ points in the state space. Assuming that the\nsamples are drawn either independently or ergodically from some measure $\\mu$,\nit was shown that, in the limit as $M\\rightarrow\\infty$, the EDMD operator\n$\\mathcal{K}_{N,M}$ converges to $\\mathcal{K}_N$, where $\\mathcal{K}_N$ is the\n$L_2(\\mu)$-orthogonal projection of the action of the Koopman operator on the\nfinite-dimensional subspace of observables. In this work, we show that, as $N\n\\rightarrow \\infty$, the operator $\\mathcal{K}_N$ converges in the strong\noperator topology to the Koopman operator. This in particular implies\nconvergence of the predictions of future values of a given observable over any\nfinite time horizon, a fact important for practical applications such as\nforecasting, estimation and control. In addition, we show that accumulation\npoints of the spectra of $\\mathcal{K}_N$ correspond to the eigenvalues of the\nKoopman operator with the associated eigenfunctions converging weakly to an\neigenfunction of the Koopman operator, provided that the weak limit of\neigenfunctions is nonzero. As a by-product, we propose an analytic version of\nthe EDMD algorithm which, under some assumptions, allows one to construct\n$\\mathcal{K}_N$ directly, without the use of sampling. Finally, under\nadditional assumptions, we analyze convergence of $\\mathcal{K}_{N,N}$ (i.e.,\n$M=N$), proving convergence, along a subsequence, to weak eigenfunctions (or\neigendistributions) related to the eigenmeasures of the Perron-Frobenius\noperator. No assumptions on the observables belonging to a finite-dimensional\ninvariant subspace of the Koopman operator are required throughout.\n",
"title": "On Convergence of Extended Dynamic Mode Decomposition to the Koopman Operator"
}
| null | null | null | null | true | null |
11210
| null |
Default
| null | null |
null |
{
"abstract": " R (Version 3.5.1 patched) has an issue with its random sampling\nfunctionality. R generates random integers between $1$ and $m$ by multiplying\nrandom floats by $m$, taking the floor, and adding $1$ to the result.\nWell-known quantization effects in this approach result in a non-uniform\ndistribution on $\\{ 1, \\ldots, m\\}$. The difference, which depends on $m$, can\nbe substantial. Because the sample function in R relies on generating random\nintegers, random sampling in R is biased. There is an easy fix: construct\nrandom integers directly from random bits, rather than multiplying a random\nfloat by $m$. That is the strategy taken in Python's numpy.random.randint()\nfunction, among others. Example source code in Python is available at\nthis https URL\n(see functions getrandbits() and randbelow_from_randbits()).\n",
"title": "Random problems with R"
}
| null | null | null | null | true | null |
11211
| null |
Default
| null | null |
null |
{
"abstract": " Quasi-Normal Modes (QNM) or ringdown phase of gravitational waves provide\ncritical information about the structure of compact objects like Black Holes.\nThus, QNMs can be a tool to test General Relativity (GR) and possible\ndeviations from it. In the case of GR, it is known for a long time that a\nrelation between two types of Black Hole perturbations: scalar (Zerilli) and\nvector (Regge-Wheeler), leads to an equal share of emitted gravitational\nenergy. With the direct detection of Gravitational waves, it is now natural to\nask: whether the same relation (between scalar and vector perturbations) holds\nfor modified gravity theories? If not, whether one can use this as a way to\nprobe deviations from General Relativity. As a first step, we show explicitly\nthat the above relation between Regge-Wheeler and Zerilli breaks down for a\ngeneral f (R) model, and hence the two perturbations do not share equal amounts\nof emitted gravitational energy. We discuss the implication of this imbalance\non observations and the no-hair conjecture.\n",
"title": "Quasinormal modes as a distinguisher between general relativity and f(R) gravity"
}
| null | null |
[
"Physics"
] | null | true | null |
11212
| null |
Validated
| null | null |
null |
{
"abstract": " The investigations on higher-order type theories and on the related notion of\nparametric polymorphism constitute the technical counterpart of the old\nfoundational problem of the circularity (or impredicativity) of second and\nhigher order logic. However, the epistemological significance of such\ninvestigations, and of their often non trivial results, has not received much\nattention in the contemporary foundational debate. The results recalled in this\npaper suggest that the question of the circularity of second order logic cannot\nbe reduced to the simple assessment of a vicious circle. Through a comparison\nbetween the faulty consistency arguments given by Frege and Martin-Löf,\nrespectively for the logical system of the Grundgesetze (shown inconsistent by\nRussell's paradox) and for the intuitionistic type theory with a type of all\ntypes (shown inconsistent by Girard's paradox), and the normalization argument\nfor second order type theory (or System F), we indicate a bunch of subtle\nmathematical problems and logical concepts hidden behind the hazardous idea of\nimpredicative quantification, constituting a vast (and largely unexplored)\ndomain for foundational research.\n",
"title": "Polymorphism and the obstinate circularity of second order logic: a victims' tale"
}
| null | null | null | null | true | null |
11213
| null |
Default
| null | null |
null |
{
"abstract": " An evaluation of FBST, Fully Bayesian Significance Test, restricted to\nsurvival models is the main objective of the present paper. A Survival\ndistribution should be chosen among the tree celebrated ones, lognormal, gamma,\nand Weibull. For this discrimination, a linear mixture of the three\ndistributions, for which the mixture weights are defined by a Dirichlet\ndistribution of order three, is an important tool: the FBST is used to test the\nhypotheses defined on the mixture weights space. Another feature of the paper\nis that all three distributions are reparametrized in that all the six\nparameters - two for each distribution - are written as functions of the mean\nand the variance of the population been studied. Note that the three\ndistributions share the same two parameters in the mixture model. The mixture\ndensity has then four parameters, the same two for the three discriminating\ndensities and two for the mixture weights. Some numerical results from\nsimulations with some right-censored data are considered. The\nlognormal-gamma-Weibull model is also applied to a real study with dataset\nbeing composed by patient's survival times of patients in the end-stage of\nchronic kidney failure subjected to hemodialysis procedures; data from Rio de\nJaneiro hospitals. The posterior density of the weights indicates an order of\nthe mixture weights and the FBST is used for discriminating between the three\nsurvival distributions.\nKeywords: Model choice; Separate Models; Survival distributions; Mixture\nmodel; Significance test; FBST\n",
"title": "Bayesian significance test for discriminating between survival distributions"
}
| null | null | null | null | true | null |
11214
| null |
Default
| null | null |
null |
{
"abstract": " We propose a minimal solution for pose estimation using both points and lines\nfor a multi-perspective camera. In this paper, we treat the multi-perspective\ncamera as a collection of rigidly attached perspective cameras. These type of\nimaging devices are useful for several computer vision applications that\nrequire a large coverage such as surveillance, self-driving cars, and\nmotion-capture studios. While prior methods have considered the cases using\nsolely points or lines, the hybrid case involving both points and lines has not\nbeen solved for multi-perspective cameras. We present the solutions for two\ncases. In the first case, we are given 2D to 3D correspondences for two points\nand one line. In the later case, we are given 2D to 3D correspondences for one\npoint and two lines. We show that the solution for the case of two points and\none line can be formulated as a fourth degree equation. This is interesting\nbecause we can get a closed-form solution and thereby achieve high\ncomputational efficiency. The later case involving two lines and one point can\nbe mapped to an eighth degree equation. We show simulations and real\nexperiments to demonstrate the advantages and benefits over existing methods.\n",
"title": "A Minimal Closed-Form Solution for Multi-Perspective Pose Estimation using Points and Lines"
}
| null | null | null | null | true | null |
11215
| null |
Default
| null | null |
null |
{
"abstract": " Embedding methods such as word embedding have become pillars for many\napplications containing discrete structures. Conventional embedding methods\ndirectly associate each symbol with a continuous embedding vector, which is\nequivalent to applying linear transformation based on \"one-hot\" encoding of the\ndiscrete symbols. Despite its simplicity, such approach yields number of\nparameters that grows linearly with the vocabulary size and can lead to\noverfitting. In this work we propose a much more compact K-way D-dimensional\ndiscrete encoding scheme to replace the \"one-hot\" encoding. In \"KD encoding\",\neach symbol is represented by a $D$-dimensional code, and each of its dimension\nhas a cardinality of $K$. The final symbol embedding vector can be generated by\ncomposing the code embedding vectors. To learn the semantically meaningful\ncode, we derive a relaxed discrete optimization technique based on stochastic\ngradient descent. By adopting the new coding system, the efficiency of\nparameterization can be significantly improved (from linear to logarithmic),\nand this can also mitigate the over-fitting problem. In our experiments with\nlanguage modeling, the number of embedding parameters can be reduced by 97\\%\nwhile achieving similar or better performance.\n",
"title": "Learning K-way D-dimensional Discrete Code For Compact Embedding Representations"
}
| null | null | null | null | true | null |
11216
| null |
Default
| null | null |
null |
{
"abstract": " RNA-binding proteins (RBPs) play crucial roles in many biological processes,\ne.g. gene regulation. Computational identification of RBP binding sites on RNAs\nare urgently needed. In particular, RBPs bind to RNAs by recognizing sequence\nmotifs. Thus, fast locating those motifs on RNA sequences is crucial and\ntime-efficient for determining whether the RNAs interact with the RBPs or not.\nIn this study, we present an attention based convolutional neural network,\niDeepA, to predict RNA-protein binding sites from raw RNA sequences. We first\nencode RNA sequences into one-hot encoding. Next, we design a deep learning\nmodel with a convolutional neural network (CNN) and an attention mechanism,\nwhich automatically search for important positions, e.g. binding motifs, to\nlearn discriminant high-level features for predicting RBP binding sites. We\nevaluate iDeepA on publicly gold-standard RBP binding sites derived from\nCLIP-seq data. The results demonstrate iDeepA achieves comparable performance\nwith other state-of-the-art methods.\n",
"title": "Attention based convolutional neural network for predicting RNA-protein binding sites"
}
| null | null |
[
"Computer Science",
"Statistics"
] | null | true | null |
11217
| null |
Validated
| null | null |
null |
{
"abstract": " Transition metal oxides (TMOs) are complex electronic systems which exhibit a\nmultitude of collective phenomena. Two archetypal examples are VO2 and NdNiO3,\nwhich undergo a metal-insulator phase-transition (MIT), the origin of which is\nstill under debate. Here we report the discovery of a memory effect in both\nsystems, manifest through an increase of resistance at a specific temperature,\nwhich is set by reversing the temperature-ramp from heating to cooling during\nthe MIT. The characteristics of this ramp-reversal memory effect do not\ncoincide with any previously reported history or memory effects in manganites,\nelectron-glass or magnetic systems. From a broad range of experimental\nfeatures, supported by theoretical modelling, we find that the main ingredients\nfor the effect to arise are the spatial phase-separation of metallic and\ninsulating regions during the MIT and the coupling of lattice strain to the\nlocal critical temperature of the phase transition. We conclude that the\nemergent memory effect originates from phase boundaries at the\nreversal-temperature leaving `scars` in the underlying lattice structure,\ngiving rise to a local increase in the transition temperature. The universality\nand robustness of the effect shed new light on the MIT in complex oxides.\n",
"title": "Ramp Reversal Memory and Phase-Boundary Scarring in Transition Metal Oxides"
}
| null | null | null | null | true | null |
11218
| null |
Default
| null | null |
null |
{
"abstract": " In the presence of background noise and interference, arrival times picked\nfrom a surface microseismic data set usually include a number of false picks\nwhich lead to uncertainty in location estimation. To eliminate false picks and\nimprove the accuracy of location estimates, we develop a classification\nalgorithm (RATEC) that clusters picked arrival times into event groups based on\nrandom sampling and fitting moveout curves that approximate hyperbolas. Arrival\ntimes far from the fitted hyperbolas are classified as false picks and removed\nfrom the data set prior to location estimation. Simulations of synthetic data\nfor a 1-D linear array show that RATEC is robust under different noise\nconditions and generally applicable to various types of media. By generalizing\nthe underlying moveout model, RATEC is extended to the case of a 2-D surface\nmonitoring array. The effectiveness of event location for the 2-D case is\ndemonstrated using a data set collected by a 5200-element dense 2-D array\ndeployed for microearthquake monitoring.\n",
"title": "A multi-channel approach for automatic microseismic event localization using RANSAC-based arrival time event clustering(RATEC)"
}
| null | null | null | null | true | null |
11219
| null |
Default
| null | null |
null |
{
"abstract": " Currently, diagnosis of skin diseases is based primarily on visual pattern\nrecognition skills and expertise of the physician observing the lesion. Even\nthough dermatologists are trained to recognize patterns of morphology, it is\nstill a subjective visual assessment. Tools for automated pattern recognition\ncan provide objective information to support clinical decision-making.\nNoninvasive skin imaging techniques provide complementary information to the\nclinician. In recent years, optical coherence tomography has become a powerful\nskin imaging technique. According to specific functional needs, skin\narchitecture varies across different parts of the body, as do the textural\ncharacteristics in OCT images. There is, therefore, a critical need to\nsystematically analyze OCT images from different body sites, to identify their\nsignificant qualitative and quantitative differences. Sixty-three optical and\ntextural features extracted from OCT images of healthy and diseased skin are\nanalyzed and in conjunction with decision-theoretic approaches used to create\ncomputational models of the diseases. We demonstrate that these models provide\nobjective information to the clinician to assist in the diagnosis of\nabnormalities of cutaneous microstructure, and hence, aid in the determination\nof treatment. Specifically, we demonstrate the performance of this methodology\non differentiating basal cell carcinoma (BCC) and squamous cell carcinoma (SCC)\nfrom healthy tissue.\n",
"title": "Universal in vivo Textural Model for Human Skin based on Optical Coherence Tomograms"
}
| null | null | null | null | true | null |
11220
| null |
Default
| null | null |
null |
{
"abstract": " Bayesian optimization (BO) has become an effective approach for black-box\nfunction optimization problems when function evaluations are expensive and the\noptimum can be achieved within a relatively small number of queries. However,\nmany cases, such as the ones with high-dimensional inputs, may require a much\nlarger number of observations for optimization. Despite an abundance of\nobservations thanks to parallel experiments, current BO techniques have been\nlimited to merely a few thousand observations. In this paper, we propose\nensemble Bayesian optimization (EBO) to address three current challenges in BO\nsimultaneously: (1) large-scale observations; (2) high dimensional input\nspaces; and (3) selections of batch queries that balance quality and diversity.\nThe key idea of EBO is to operate on an ensemble of additive Gaussian process\nmodels, each of which possesses a randomized strategy to divide and conquer. We\nshow unprecedented, previously impossible results of scaling up BO to tens of\nthousands of observations within minutes of computation.\n",
"title": "Batched Large-scale Bayesian Optimization in High-dimensional Spaces"
}
| null | null | null | null | true | null |
11221
| null |
Default
| null | null |
null |
{
"abstract": " We study networks of firms with Leontief production functions. Relying on\nresults from Random Matrix Theory, we argue that such networks generically\nbecome unstable when their size increases, or when the heterogeneity in\nproductivities/connectivities becomes too strong. At marginal stability and for\nlarge heterogeneities, we find that the distribution of firm sizes develops a\npower-law tail, as observed empirically. Crises can be triggered by small\nidiosyncratic shocks, which lead to \"avalanches\" of defaults characterized by a\npower-law distribution of total output losses. We conjecture that evolutionary\nand behavioural forces conspire to keep the economy close to marginal\nstability. This scenario would naturally explain the well-known \"small shocks,\nlarge business cycles\" puzzle, as anticipated long ago by Bak, Chen, Scheinkman\nand Woodford.\n",
"title": "Will a Large Economy Be Stable?"
}
| null | null |
[
"Quantitative Finance"
] | null | true | null |
11222
| null |
Validated
| null | null |
null |
{
"abstract": " In this paper, we study the stochastic gradient descent (SGD) method for the\nnonconvex nonsmooth optimization, and propose an accelerated SGD method by\ncombining the variance reduction technique with Nesterov's extrapolation\ntechnique. Moreover, based on the local error bound condition, we establish the\nlinear convergence of our method to obtain a stationary point of the nonconvex\noptimization. In particular, we prove that not only the sequence generated\nlinearly converges to a stationary point of the problem, but also the\ncorresponding sequence of objective values is linearly convergent. Finally,\nsome numerical experiments demonstrate the effectiveness of our method. To the\nbest of our knowledge, it is first proved that the accelerated SGD method\nconverges linearly to the local minimum of the nonconvex optimization.\n",
"title": "Linear Convergence of Accelerated Stochastic Gradient Descent for Nonconvex Nonsmooth Optimization"
}
| null | null |
[
"Mathematics",
"Statistics"
] | null | true | null |
11223
| null |
Validated
| null | null |
null |
{
"abstract": " The consistent demand for better performance has lead to innovations at\nhardware and microarchitectural levels. 3D stacking of memory and logic dies\ndelivers an order of magnitude improvement in available memory bandwidth. The\nprice paid however is, tight thermal constraints.\nIn this paper, we study the complex multiphysics interactions between\nperformance, energy and temperature. Using a cache coherent multicore processor\ncycle level simulator coupled with power and thermal estimation tools, we\ninvestigate the interactions between (a) thermal behaviors (b) compute and\nmemory microarchitecture and (c) application workloads. The key insights from\nthis exploration reveal the need to manage performance, energy and temperature\nin a coordinated fashion. Furthermore, we identify the concept of \"effective\nheat capacity\" i.e. the heat generated beyond which no further gains in\nperformance is observed with increases in voltage-frequency of the compute\nlogic. Subsequently, a real-time, numerical optimization based, application\nagnostic controller (TRINITY) is developed which intelligently manages the\nthree parameters of interest. We observe up to $30\\%$ improvement in Energy\nDelay$^2$ Product and up to $8$ Kelvin lower core temperatures as compared to\nfixed frequencies. Compared to the \\texttt{ondemand} Linux CPU DVFS governor,\nfor similar energy efficiency, TRINITY keeps the cores cooler by $6$ Kelvin\nwhich increases the lifetime reliability by up to 59\\%.\n",
"title": "TRINITY: Coordinated Performance, Energy and Temperature Management in 3D Processor-Memory Stacks"
}
| null | null | null | null | true | null |
11224
| null |
Default
| null | null |
null |
{
"abstract": " Covariate shift relaxes the widely-employed independent and identically\ndistributed (IID) assumption by allowing different training and testing input\ndistributions. Unfortunately, common methods for addressing covariate shift by\ntrying to remove the bias between training and testing distributions using\nimportance weighting often provide poor performance guarantees in theory and\nunreliable predictions with high variance in practice. Recently developed\nmethods that construct a predictor that is inherently robust to the\ndifficulties of learning under covariate shift are restricted to minimizing\nlogloss and can be too conservative when faced with high-dimensional learning\ntasks. We address these limitations in two ways: by robustly minimizing various\nloss functions, including non-convex ones, under the testing distribution; and\nby separately shaping the influence of covariate shift according to different\nfeature-based views of the relationship between input variables and example\nlabels. These generalizations make robust covariate shift prediction applicable\nto more task scenarios. We demonstrate the benefits on classification under\ncovariate shift tasks.\n",
"title": "Robust Covariate Shift Prediction with General Losses and Feature Views"
}
| null | null |
[
"Computer Science",
"Statistics"
] | null | true | null |
11225
| null |
Validated
| null | null |
null |
{
"abstract": " Across smart-grid and smart-city applications, there are problems where an\nensemble of agents is to be controlled such that both the aggregate behaviour\nand individual-level perception of the system's performance are acceptable. In\nmany applications, traditional PI control is used to regulate aggregate\nensemble performance. Our principal contribution in this note is to demonstrate\nthat PI control may not be always suitable for this purpose, and in some\nsituations may lead to a loss of ergodicity for closed-loop systems. Building\non this observation, a theoretical framework is proposed to both analyse and\ndesign control systems for the regulation of large scale ensembles of agents\nwith a probabilistic intent. Examples are given to illustrate our results.\n",
"title": "On the Ergodic Control of Ensembles"
}
| null | null | null | null | true | null |
11226
| null |
Default
| null | null |
null |
{
"abstract": " The common feature of various plasmonic schemes is their ability to confine\noptical fields of surface plasmon polaritons (SPPs) into sub-wavelength volumes\nand thus achieve a large enhancement of linear and nonlinear optical\nproperties. This ability, however, is severely limited by the large ohmic loss\ninherent to even the best of metals. However, in the mid and far infrared\nranges of the spectrum there exists a viable alternative to metals, polar\ndielectrics and semiconductors in which dielectric permittivity (the real part)\nturns negative in the Reststrahlen region. This feature engenders the so-called\nsurface phonon polaritons (SPhPs) capable of confining the field in a way akin\nto their plasmonic analogues, the SPPs. Since the damping rate of polar phonons\nis substantially less than that of free electrons, it is not unreasonable to\nexpect that phononic devices may outperform their plasmonic counterparts. Yet a\nmore rigorous analysis of the comparative merits of phononics and plasmonics\nreveals a more nuanced answer, namely that while phononic schemes do exhibit\nnarrower resonances and can achieve a very high degree of energy concentration,\nmost of the energy is contained in the form of lattice vibrations so that\nenhancement of the electric field, and hence the Purcell factor, is rather\nsmall compared to what can be achieved with metal nanoantennas. Still, the\nsheer narrowness of phononic resonances is expected to make phononics viable in\napplications where frequency selectivity is important.\n",
"title": "Relative merits of Phononics vs. Plasmonics: the energy balance approach"
}
| null | null |
[
"Physics"
] | null | true | null |
11227
| null |
Validated
| null | null |
null |
{
"abstract": " We present a method of memory footprint reduction for FFT-based,\nelectromagnetic (EM) volume integral equation (VIE) formulations. The arising\nGreen's function tensors have low multilinear rank, which allows Tucker\ndecomposition to be employed for their compression, thereby greatly reducing\nthe required memory storage for numerical simulations. Consequently, the\ncompressed components are able to fit inside a graphical processing unit (GPU)\non which highly parallelized computations can vastly accelerate the iterative\nsolution of the arising linear system. In addition, the element-wise products\nthroughout the iterative solver's process require additional flops, thus, we\nprovide a variety of novel and efficient methods that maintain the linear\ncomplexity of the classic element-wise product with an additional\nmultiplicative small constant. We demonstrate the utility of our approach via\nits application to VIE simulations for the Magnetic Resonance Imaging (MRI) of\na human head. For these simulations we report an order of magnitude\nacceleration over standard techniques.\n",
"title": "Memory footprint reduction for the FFT-based volume integral equation method via tensor decompositions"
}
| null | null | null | null | true | null |
11228
| null |
Default
| null | null |
null |
{
"abstract": " In this note we prove the Payne-type conjecture about the behaviour of the\nnodal set of least energy sign-changing solutions for the equation $-\\Delta_p u\n= f(u)$ in bounded Steiner symmetric domains $\\Omega \\subset \\mathbb{R}^N$\nunder the zero Dirichlet boundary conditions. The nonlinearity $f$ is assumed\nto be either superlinear or resonant. In the latter case, least energy\nsign-changing solutions are second eigenfunctions of the zero Dirichlet\n$p$-Laplacian in $\\Omega$. We show that the nodal set of any least energy\nsign-changing solution intersects the boundary of $\\Omega$. The proof is based\non a moving polarization argument.\n",
"title": "On a property of the nodal set of least energy sign-changing solutions for quasilinear elliptic equations"
}
| null | null | null | null | true | null |
11229
| null |
Default
| null | null |
null |
{
"abstract": " The aim of this note is to give an alternative proof of a theorem of Koras\nand Russell, that is, a characterization of smooth contractible affine\nvarieties endowed with a hyperbolic action of the group\n$\\mathbb{G}_{m}\\simeq\\mathbb{C}^{\\text{*}}$, using the language of polyhedral\ndivisors developed by Altmann and Hausen as generalization of\n$\\mathbb{Q}$-divisors.\n",
"title": "Smooth contractible threefolds with hyperbolic $\\mathbb{G}_{m}$-actions via ps-divisors"
}
| null | null |
[
"Mathematics"
] | null | true | null |
11230
| null |
Validated
| null | null |
null |
{
"abstract": " The paper is primarily concerned with the asymptotic behavior as $N\\to\\infty$\nof averages of nonconventional arrays having the form\n$N^{-1}\\sum_{n=1}^N\\prod_{j=1}^\\ell T^{P_j(n,N)}f_j$ where $f_j$'s are bounded\nmeasurable functions, $T$ is an invertible measure preserving transformation\nand $P_j$'s are polynomials of $n$ and $N$ taking on integer values on\nintegers. It turns out that when $T$ is weakly mixing and $P_j(n,N)=p_jn+q_jN$\nare linear or, more generally, have the form $P_j(n,N)=P_j(n)+Q_j(N)$ for some\ninteger valued polynomials $P_j$ and $Q_j$ then the above averages converge in\n$L^2$ but for general polynomials $P_j$ the $L^2$ convergence can be ensured\neven in the case $\\ell=1$ only when $T$ is strongly mixing. Studying also\nweakly mixing and compact extensions and relying on Furstenberg's structure\ntheorem we derive an extension of Szemer\\' edi's theorem saying that for any\nsubset of integers $\\Lambda$ with positive upper density there exists a subset\n$\\mathcal N_\\Lambda$ of positive integers having uniformly bounded gaps such\nthat for $N\\in\\mathcal N_\\Lambda$ and at least $\\varepsilon N,\\,\\varepsilon>0$\nof $n$'s all numbers $p_jn+q_jN,\\, j=1,...,\\ell$ belong to $\\Lambda$. We obtain\nalso a version of these results for several commuting transformations which\nyields a corresponding extension of the multidimensional Szemer\\' edi theorem.\n",
"title": "Ergodic Theorems for Nonconventional Arrays and an Extension of the Szemeredi Theorem"
}
| null | null | null | null | true | null |
11231
| null |
Default
| null | null |
null |
{
"abstract": " This paper develops an inverse reinforcement learning algorithm aimed at\nrecovering a reward function from the observed actions of an agent. We\nintroduce a strategy to flexibly handle different types of actions with two\napproximations of the Bellman Optimality Equation, and a Bellman Gradient\nIteration method to compute the gradient of the Q-value with respect to the\nreward function. These methods allow us to build a differentiable relation\nbetween the Q-value and the reward function and learn an approximately optimal\nreward function with gradient methods. We test the proposed method in two\nsimulated environments by evaluating the accuracy of different approximations\nand comparing the proposed method with existing solutions. The results show\nthat even with a linear reward function, the proposed method has a comparable\naccuracy with the state-of-the-art method adopting a non-linear reward\nfunction, and the proposed method is more flexible because it is defined on\nobserved actions instead of trajectories.\n",
"title": "Bellman Gradient Iteration for Inverse Reinforcement Learning"
}
| null | null | null | null | true | null |
11232
| null |
Default
| null | null |
null |
{
"abstract": " We consider the question of accurately and efficiently computing low-rank\nmatrix or tensor factorizations given data compressed via random projections.\nThis problem arises naturally in the many settings in which data is acquired\nvia compressive sensing. We examine the approach of first performing\nfactorization in the compressed domain, and then reconstructing the original\nhigh-dimensional factors from the recovered (compressed) factors. In both the\ntensor and matrix settings, we establish conditions under which this natural\napproach will provably recover the original factors. We support these\ntheoretical results with experiments on synthetic data and demonstrate the\npractical applicability of our methods on real-world gene expression and EEG\ntime series data.\n",
"title": "Fast and Accurate Low-Rank Factorization of Compressively-Sensed Data"
}
| null | null |
[
"Computer Science",
"Statistics"
] | null | true | null |
11233
| null |
Validated
| null | null |
null |
{
"abstract": " In this work, we derive a new kind of rainbow functions, which has\ngeneralized uncertainty principle parameter. Then, we investigate modified\nthermodynamic quantities and phase transition of rainbow Schwarzschild black\nhole by employing this new kind of rainbow functions. Our results demonstrate\nthat the effect of rainbow gravity and generalized uncertainty principle have a\ngreat effect on the picture of Hawking radiation. It prevents black holes from\ntotal evaporation and causes the remnant. In addition, after analyzing the the\nmodified local thermodynamic quantities, we find that effect of rainbow gravity\nand generalized uncertainty principle lead to one first-order phase transition,\ntwo second-order phase transitions, and two Hawking-Page-type phase transitions\nin the thermodynamic system of rainbow Schwarzschild black hole.\n",
"title": "Quantum gravity corrections to the thermodynamics and phase transition of Schwarzschild black hole"
}
| null | null | null | null | true | null |
11234
| null |
Default
| null | null |
null |
{
"abstract": " We reinterpret Kim's non-abelian reciprocity maps for algebraic varieties as\nobstruction towers of mapping spaces of etale homotopy types, removing\ntechnical hypotheses such as global basepoints and cohomological constraints.\nWe then extend the theory by considering alternative natural series of\nextensions, one of which gives an obstruction tower whose first stage is the\nBrauer--Manin obstruction, allowing us to determine when Kim's maps recover the\nBrauer-Manin locus. A tower based on relative completions yields non-trivial\nreciprocity maps even for Shimura varieties; for the stacky modular curve,\nthese take values in Galois cohomology of modular forms, and give obstructions\nto an adelic elliptic curve with global Tate module underlying a global\nelliptic curve.\n",
"title": "Non-abelian reciprocity laws and higher Brauer-Manin obstructions"
}
| null | null |
[
"Mathematics"
] | null | true | null |
11235
| null |
Validated
| null | null |
null |
{
"abstract": " Instance- and label-dependent label noise (ILN) is widely existed in\nreal-world datasets but has been rarely studied. In this paper, we focus on a\nparticular case of ILN where the label noise rates, representing the\nprobabilities that the true labels of examples flip into the corrupted labels,\nhave upper bounds. We propose to handle this bounded instance- and\nlabel-dependent label noise under two different conditions. First,\ntheoretically, we prove that when the marginal distributions $P(X|Y=+1)$ and\n$P(X|Y=-1)$ have non-overlapping supports, we can recover every noisy example's\ntrue label and perform supervised learning directly on the cleansed examples.\nSecond, for the overlapping situation, we propose a novel approach to learn a\nwell-performing classifier which needs only a few noisy examples to be labeled\nmanually. Experimental results demonstrate that our method works well on both\nsynthetic and real-world datasets.\n",
"title": "Learning with Bounded Instance- and Label-dependent Label Noise"
}
| null | null | null | null | true | null |
11236
| null |
Default
| null | null |
null |
{
"abstract": " We study the problem of community detection in hypergraphs under a stochastic\nblock model. Similarly to how the stochastic block model in graphs suggests\nstudying spiked random matrices, our model motivates investigating statistical\nand computational limits of exact recovery in a certain spiked tensor model. In\ncontrast with the matrix case, the spiked model naturally arising from\ncommunity detection in hypergraphs is different from the one arising in the\nso-called tensor Principal Component Analysis model. We investigate the\neffectiveness of algorithms in the Sum-of-Squares hierarchy on these models.\nInterestingly, our results suggest that these two apparently similar models\nexhibit significantly different computational to statistical gaps.\n",
"title": "Community Detection in Hypergraphs, Spiked Tensor Models, and Sum-of-Squares"
}
| null | null | null | null | true | null |
11237
| null |
Default
| null | null |
null |
{
"abstract": " We give finite presentations of the saturated cluster modular groups of type\n$X_6$ and $X_7$. We compute the first homology of these groups and conclude\nthat they are different from Artin-Tits braid groups and mapping class groups\nof surfaces. We verify that the cluster modular group of type $X_7$ is\ngenerated by cluster Dehn twists. Further we discuss several relations between\nthese cluster modular groups and the mapping class group of an annulus.\n",
"title": "Presentations of the saturated cluster modular groups of finite mutation type $X_6$ and $X_7$"
}
| null | null | null | null | true | null |
11238
| null |
Default
| null | null |
null |
{
"abstract": " We prove a characterization of $t$-query quantum algorithms in terms of the\nunit ball of a space of degree-$2t$ polynomials. Based on this, we obtain a\nrefined notion of approximate polynomial degree that equals the quantum query\ncomplexity, answering a question of Aaronson et al. (CCC'16). Our proof is\nbased on a fundamental result of Christensen and Sinclair (J. Funct. Anal.,\n1987) that generalizes the well-known Stinespring representation for quantum\nchannels to multilinear forms. Using our characterization, we show that many\npolynomials of degree four are far from those coming from two-query quantum\nalgorithms. We also give a simple and short proof of one of the results of\nAaronson et al. showing an equivalence between one-query quantum algorithms and\nbounded quadratic polynomials.\n",
"title": "Quantum Query Algorithms are Completely Bounded Forms"
}
| null | null | null | null | true | null |
11239
| null |
Default
| null | null |
null |
{
"abstract": " We present the Parallel, Forward-Backward with Pruning (PFBP) algorithm for\nfeature selection (FS) in Big Data settings (high dimensionality and/or sample\nsize). To tackle the challenges of Big Data FS PFBP partitions the data matrix\nboth in terms of rows (samples, training examples) as well as columns\n(features). By employing the concepts of $p$-values of conditional independence\ntests and meta-analysis techniques PFBP manages to rely only on computations\nlocal to a partition while minimizing communication costs. Then, it employs\npowerful and safe (asymptotically sound) heuristics to make early, approximate\ndecisions, such as Early Dropping of features from consideration in subsequent\niterations, Early Stopping of consideration of features within the same\niteration, or Early Return of the winner in each iteration. PFBP provides\nasymptotic guarantees of optimality for data distributions faithfully\nrepresentable by a causal network (Bayesian network or maximal ancestral\ngraph). Our empirical analysis confirms a super-linear speedup of the algorithm\nwith increasing sample size, linear scalability with respect to the number of\nfeatures and processing cores, while dominating other competitive algorithms in\nits class.\n",
"title": "Massively-Parallel Feature Selection for Big Data"
}
| null | null | null | null | true | null |
11240
| null |
Default
| null | null |
null |
{
"abstract": " The detection of gravitational waves (GWs) generated by merging black holes\nhas recently opened up a new observational window into the Universe. The mass\nof the black holes in the first and third LIGO detections, ($36-29 \\,\n\\mathrm{M_{\\odot}}$ and $32-19 \\, \\mathrm{M_{\\odot}}$), suggests\nlow-metallicity stars as their most likely progenitors. Based on\nhigh-resolution N-body simulations, coupled with state-of-the-art metal\nenrichment models, we find that the remnants of Pop III stars are\npreferentially located within the cores of galaxies. The probability of a GW\nsignal to be generated by Pop III stars reaches $\\sim 90\\%$ at $\\sim 0.5 \\,\n\\mathrm{kpc}$ from the galaxy center, compared to a benchmark value of $\\sim\n5\\%$ outside the core. The predicted merger rates inside bulges is $\\sim 60\n\\times \\beta_{III} \\, \\mathrm{Gpc^{-3} \\, yr^{-1}}$ ($\\beta_{III}$ is the Pop\nIII binarity fraction). To match the $90\\%$ credible range of LIGO merger\nrates, we obtain: $0.03 < \\beta_{III} < 0.88$. Future advances in GW\nobservatories and the discovery of possible electromagnetic counterparts could\nallow the localization of such sources within their host galaxies. The\npreferential concentration of GW events within the bulge of galaxies would then\nprovide an indirect proof for the existence of Pop III stars.\n",
"title": "Gravitational Wave Sources from Pop III Stars are Preferentially Located within the Cores of their Host Galaxies"
}
| null | null | null | null | true | null |
11241
| null |
Default
| null | null |
null |
{
"abstract": " A Markov-chain model is developed for the purpose estimation of the cure rate\nof non-performing loans. The technique is performed collectively, on portfolios\nand it can be applicable in the process of calculation of credit impairment. It\nis efficient in terms of data manipulation costs which makes it accessible even\nto smaller financial institutions. In addition, several other applications to\nportfolio optimization are suggested.\n",
"title": "A Markov Chain Model for the Cure Rate of Non-Performing Loans"
}
| null | null | null | null | true | null |
11242
| null |
Default
| null | null |
null |
{
"abstract": " Note that this paper is superceded by \"Black-Box Adversarial Attacks with\nLimited Queries and Information.\"\nCurrent neural network-based image classifiers are susceptible to adversarial\nexamples, even in the black-box setting, where the attacker is limited to query\naccess without access to gradients. Previous methods --- substitute networks\nand coordinate-based finite-difference methods --- are either unreliable or\nquery-inefficient, making these methods impractical for certain problems.\nWe introduce a new method for reliably generating adversarial examples under\nmore restricted, practical black-box threat models. First, we apply natural\nevolution strategies to perform black-box attacks using two to three orders of\nmagnitude fewer queries than previous methods. Second, we introduce a new\nalgorithm to perform targeted adversarial attacks in the partial-information\nsetting, where the attacker only has access to a limited number of target\nclasses. Using these techniques, we successfully perform the first targeted\nadversarial attack against a commercially deployed machine learning system, the\nGoogle Cloud Vision API, in the partial information setting.\n",
"title": "Query-Efficient Black-box Adversarial Examples (superceded)"
}
| null | null |
[
"Computer Science",
"Statistics"
] | null | true | null |
11243
| null |
Validated
| null | null |
null |
{
"abstract": " A family $\\mathcal F\\subset {[n]\\choose k}$ is $U(s,q)$ of for any\n$F_1,\\ldots, F_s\\in \\mathcal F$ we have $|F_1\\cup\\ldots\\cup F_s|\\le q$. This\nnotion generalizes the property of a family to be $t$-intersecting and to have\nmatching number smaller than $s$.\nIn this paper, we find the maximum $|\\mathcal F|$ for $\\mathcal F$ that are\n$U(s,q)$, provided $n>C(s,q)k$ with moderate $C(s,q)$. In particular, we\ngeneralize the result of the first author on the Erdős Matching Conjecture\nand prove a generalization of the Erdős-Ko-Rado theorem, which states that\nfor $n> s^2k$ the largest family $\\mathcal F\\subset {[n]\\choose k}$ with\nproperty $U(s,s(k-1)+1)$ is the star and is in particular intersecting.\n(Conversely, it is easy to see that any intersecting family in ${[n]\\choose k}$\nis $U(s,s(k-1)+1)$.)\nWe investigate the case $k=3$ more thoroughly, showing that, unlike in the\ncase of the Erdős Matching Conjecture, in general there may be $3$ extremal\nfamilies.\n",
"title": "Beyond the Erdős Matching Conjecture"
}
| null | null | null | null | true | null |
11244
| null |
Default
| null | null |
null |
{
"abstract": " Electrostatic interactions play a fundamental role in the structure and\nfunction of proteins. Due to ionizable amino acid residues present on the\nsolvent-exposed surfaces of proteins, the protein charge is not constant but\nvaries with the changes in the environment -- most notably, the pH of the\nsurrounding solution. We study the effects of pH on the charge of four globular\nproteins by expanding their surface charge distributions in terms of\nmultipoles. The detailed representation of the charges on the proteins is in\nthis way replaced by the magnitudes and orientations of the multipole moments\nof varying order. Focusing on the three lowest-order multipoles -- the total\ncharge, dipole, and quadrupole moment -- we show that the value of pH\ninfluences not only their magnitudes, but more notably and importantly also the\nspatial orientation of their principal axes. Our findings imply important\nconsequences for the study of protein-protein interactions and the assembly of\nboth proteinaceous shells and patchy colloids with dissociable charge groups.\n",
"title": "pH dependence of charge multipole moments in proteins"
}
| null | null | null | null | true | null |
11245
| null |
Default
| null | null |
null |
{
"abstract": " The theory of receptor-ligand binding equilibria has long been\nwell-established in biochemistry, and was primarily constructed to describe\ndilute aqueous solutions. Accordingly, few computational approaches have been\ndeveloped for making quantitative predictions of binding probabilities in\nenvironments other than dilute isotropic solution. Existing techniques, ranging\nfrom simple automated docking procedures to sophisticated thermodynamics-based\nmethods, have been developed with soluble proteins in mind. Biologically and\npharmacologically relevant protein-ligand interactions often occur in complex\nenvironments, including lamellar phases like membranes and crowded, non-dilute\nsolutions. Here we revisit the theoretical bases of ligand binding equilibria,\navoiding overly specific assumptions that are nearly always made when\ndescribing receptor-ligand binding. Building on this formalism, we extend the\nasymptotically exact Alchemical Free Energy Perturbation technique to\nquantifying occupancies of sites on proteins in a complex bulk, including\nphase-separated, anisotropic, or non-dilute solutions, using a\nthermodynamically consistent and easily generalized approach that resolves\nseveral ambiguities of current frameworks. To incorporate the complex bulk\nwithout overcomplicating the overall thermodynamic cycle, we simplify the\ncommon approach for ligand restraints by using a single\ndistance-from-bound-configuration (DBC) ligand restraint during AFEP decoupling\nfrom protein. DBC restraints should be generalizable to binding modes of most\nsmall molecules, even those with strong orientational dependence. We apply this\napproach to compute the likelihood that membrane cholesterol binds to known\ncrystallographic sites on 3 GPCRs at a range of concentrations. Non-ideality of\ncholesterol in a binary cholesterol:POPC bilayer is characterized and\nconsistently incorporated into the interpretation.\n",
"title": "A streamlined, general approach for computing ligand binding free energies and its application to GPCR-bound cholesterol"
}
| null | null | null | null | true | null |
11246
| null |
Default
| null | null |
null |
{
"abstract": " Spin-charge separation is known to be broken in many physically interesting\none-dimensional (1D) and quasi-1D systems with spin-orbit interaction because\nof which spin and charge degrees of freedom are mixed in collective\nexcitations. Mixed spin-charge modes carry an electric charge and therefore can\nbe investigated by electrical means. We explore this possibility by studying\nthe dynamic conductance of a 1D electron system with image-potential-induced\nspin-orbit interaction. The real part of the admittance reveals an oscillatory\nbehavior versus frequency that reflects the collective excitation resonances\nfor both modes at their respective transit frequencies. By analyzing the\nfrequency dependence of the conductance the mode velocities can be found and\ntheir spin-charge structure can be determined quantitatively.\n",
"title": "Dynamics of one-dimensional electrons with broken spin-charge separation"
}
| null | null |
[
"Physics"
] | null | true | null |
11247
| null |
Validated
| null | null |
null |
{
"abstract": " It is inconceivable how chaotic the world would look to humans, faced with\ninnumerable decisions a day to be made under uncertainty, had they been lacking\nthe capacity to distinguish the relevant from the irrelevant---a capacity which\ncomputationally amounts to handling probabilistic independence relations. The\nhighly parallel and distributed computational machinery of the brain suggests\nthat a satisfying process-level account of human independence judgment should\nalso mimic these features. In this work, we present the first rational,\ndistributed, message-passing, process-level account of independence judgment,\ncalled $\\mathcal{D}^\\ast$. Interestingly, $\\mathcal{D}^\\ast$ shows a curious,\nbut normatively-justified tendency for quick detection of dependencies,\nwhenever they hold. Furthermore, $\\mathcal{D}^\\ast$ outperforms all the\npreviously proposed algorithms in the AI literature in terms of worst-case\nrunning time, and a salient aspect of it is supported by recent work in\nneuroscience investigating possible implementations of Bayes nets at the neural\nlevel. $\\mathcal{D}^\\ast$ nicely exemplifies how the pursuit of cognitive\nplausibility can lead to the discovery of state-of-the-art algorithms with\nappealing properties, and its simplicity makes $\\mathcal{D}^\\ast$ potentially a\ngood candidate for pedagogical purposes.\n",
"title": "A Rational Distributed Process-level Account of Independence Judgment"
}
| null | null | null | null | true | null |
11248
| null |
Default
| null | null |
null |
{
"abstract": " In this paper we adopt a category-theoretic approach to the conception of\nautomata classes enjoying minimization by design. The main instantiation of our\nconstruction is a new class of automata that are hybrid between deterministic\nautomata and automata weighted over a field.\n",
"title": "Automata in the Category of Glued Vector Spaces"
}
| null | null | null | null | true | null |
11249
| null |
Default
| null | null |
null |
{
"abstract": " The self-consistent harmonic approximation is an effective harmonic theory to\ncalculate the free energy of systems with strongly anharmonic atomic\nvibrations, and its stochastic implementation has proved to be an efficient\nmethod to study, from first-principles, the anharmonic properties of solids.\nThe free energy as a function of average atomic positions (centroids) can be\nused to study quantum or thermal lattice instability. In particular the\ncentroids are order parameters in second-order structural phase transitions\nsuch as, e.g., charge-density-waves or ferroelectric instabilities. According\nto Landau's theory, the knowledge of the second derivative of the free energy\n(i.e. the curvature) with respect to the centroids in a high-symmetry\nconfiguration allows the identification of the phase-transition and of the\ninstability modes. In this work we derive the exact analytic formula for the\nsecond derivative of the free energy in the self-consistent harmonic\napproximation for a generic atomic configuration. The analytic derivative is\nexpressed in terms of the atomic displacements and forces in a form that can be\nevaluated by a stochastic technique using importance sampling. Our approach is\nparticularly suitable for applications based on first-principles\ndensity-functional-theory calculations, where the forces on atoms can be\nobtained with a negligible computational effort compared to total energy\ndetermination. Finally we propose a dynamical extension of the theory to\ncalculate spectral properties of strongly anharmonic phonons, as probed by\ninelastic scattering processes. We illustrate our method with a numerical\napplication on a toy model that mimics the ferroelectric transition in\nrock-salt crystals such as SnTe or GeTe.\n",
"title": "Second order structural phase transitions, free energy curvature, and temperature-dependent anharmonic phonons in the self-consistent harmonic approximation: theory and stochastic implementation"
}
| null | null | null | null | true | null |
11250
| null |
Default
| null | null |
null |
{
"abstract": " To resolve conflicts among norms, various nonmonotonic formalisms can be used\nto perform prioritized normative reasoning. Meanwhile, formal argumentation\nprovides a way to represent nonmonotonic logics. In this paper, we propose a\nrepresentation of prioritized normative reasoning by argumentation. Using\nhierarchical abstract normative systems, we define three kinds of prioritized\nnormative reasoning approaches, called Greedy, Reduction, and Optimization.\nThen, after formulating an argumentation theory for a hierarchical abstract\nnormative system, we show that for a totally ordered hierarchical abstract\nnormative system, Greedy and Reduction can be represented in argumentation by\napplying the weakest link and the last link principles respectively, and\nOptimization can be represented by introducing additional defeats capturing the\nidea that for each argument that contains a norm not belonging to the maximal\nobeyable set then this argument should be rejected.\n",
"title": "Prioritized Norms in Formal Argumentation"
}
| null | null | null | null | true | null |
11251
| null |
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| null | null |
null |
{
"abstract": " We develop fast spectral algorithms for tensor decomposition that match the\nrobustness guarantees of the best known polynomial-time algorithms for this\nproblem based on the sum-of-squares (SOS) semidefinite programming hierarchy.\nOur algorithms can decompose a 4-tensor with $n$-dimensional orthonormal\ncomponents in the presence of error with constant spectral norm (when viewed as\nan $n^2$-by-$n^2$ matrix). The running time is $n^5$ which is close to linear\nin the input size $n^4$.\nWe also obtain algorithms with similar running time to learn sparsely-used\northogonal dictionaries even when feature representations have constant\nrelative sparsity and non-independent coordinates.\nThe only previous polynomial-time algorithms to solve these problem are based\non solving large semidefinite programs. In contrast, our algorithms are easy to\nimplement directly and are based on spectral projections and tensor-mode\nrearrangements.\nOr work is inspired by recent of Hopkins, Schramm, Shi, and Steurer (STOC'16)\nthat shows how fast spectral algorithms can achieve the guarantees of SOS for\naverage-case problems. In this work, we introduce general techniques to capture\nthe guarantees of SOS for worst-case problems.\n",
"title": "Fast and robust tensor decomposition with applications to dictionary learning"
}
| null | null | null | null | true | null |
11252
| null |
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| null | null |
null |
{
"abstract": " We study the problem of testing conductance in the setting of distributed\ncomputing and give a two-sided tester that takes $\\mathcal{O}(\\log(n) /\n(\\epsilon \\Phi^2))$ rounds to decide if a graph has conductance at least $\\Phi$\nor is $\\epsilon$-far from having conductance at least $\\Phi^2 / 1000$ in the\ndistributed CONGEST model. We also show that $\\Omega(\\log n)$ rounds are\nnecessary for testing conductance even in the LOCAL model. In the case of a\nconnected graph, we show that we can perform the test even when the number of\nvertices in the graph is not known a priori. This is the first two-sided tester\nin the distributed model we are aware of. A key observation is that one can\nperform a polynomial number of random walks from a small set of vertices if it\nis sufficient to track only some small statistics of the walks. This greatly\nreduces the congestion on the edges compared to tracking each walk\nindividually.\n",
"title": "Distributed Testing of Conductance"
}
| null | null | null | null | true | null |
11253
| null |
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| null | null |
null |
{
"abstract": " Recently, single crystalline carbon nitride 2D material with a C3N\nstoichiometry has been synthesized. In this investigation, we explored the\nmechanical response and thermal transport along pristine, free-standing and\nsingle-layer C3N. To this aim, we conducted extensive first-principles density\nfunctional theory (DFT) calculations as well as molecular dynamics (MD)\nsimulations. DFT results reveal that C3N nanofilms can yield remarkably high\nelastic modulus of 341 GPa.nm and tensile strength of 35 GPa.nm, very close to\nthose of defect-free graphene. Classical MD simulations performed at a low\ntemperature, predict accurately the elastic modulus of 2D C3N with less than 3%\ndifference with the first-principles estimation. The deformation process of C3N\nnanosheets was studied both by the DFT and MD simulations. Ab initio molecular\ndynamics simulations show that single-layer C3N can withstand high temperatures\nlike 4000 K. Notably, the phononic thermal conductivity of free-standing C3N\nwas predicted to be as high as 815 W/mK. Our atomistic modelling results reveal\nultra high stiffness and thermal conductivity of C3N nanomembranes and\ntherefore propose them as promising candidates for new application such as the\nthermal management in nanoelectronics or simultaneously reinforcing the thermal\nand mechanical properties of polymeric materials.\n",
"title": "Ultra high stiffness and thermal conductivity of graphene like C3N"
}
| null | null | null | null | true | null |
11254
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| null | null |
null |
{
"abstract": " Automatic segmentation of liver lesions is a fundamental requirement towards\nthe creation of computer aided diagnosis (CAD) and decision support systems\n(CDS). Traditional segmentation approaches depend heavily upon hand-crafted\nfeatures and a priori knowledge of the user. As such, these methods are\ndifficult to adopt within a clinical environment. Recently, deep learning\nmethods based on fully convolutional networks (FCNs) have been successful in\nmany segmentation problems primarily because they leverage a large labelled\ndataset to hierarchically learn the features that best correspond to the\nshallow visual appearance as well as the deep semantics of the areas to be\nsegmented. However, FCNs based on a 16 layer VGGNet architecture have limited\ncapacity to add additional layers. Therefore, it is challenging to learn more\ndiscriminative features among different classes for FCNs. In this study, we\novercome these limitations using deep residual networks (ResNet) to segment\nliver lesions. ResNet contain skip connections between convolutional layers,\nwhich solved the problem of the training degradation of training accuracy in\nvery deep networks and thereby enables the use of additional layers for\nlearning more discriminative features. In addition, we achieve more precise\nboundary definitions through a novel cascaded ResNet architecture with\nmulti-scale fusion to gradually learn and infer the boundaries of both the\nliver and the liver lesions. Our proposed method achieved 4th place in the ISBI\n2017 Liver Tumor Segmentation Challenge by the submission deadline.\n",
"title": "Automatic Liver Lesion Detection using Cascaded Deep Residual Networks"
}
| null | null | null | null | true | null |
11255
| null |
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| null | null |
null |
{
"abstract": " In this work we characterize the combinatorial metrics admitting a\nMacWilliams-type identity and describe the group of linear isometries of such\nmetrics. Considering coverings that are not connected, we classify the metrics\nsatisfying the MacWilliams extension property.\n",
"title": "Combinatorial metrics: MacWilliams-type identities, isometries and extension property"
}
| null | null | null | null | true | null |
11256
| null |
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| null | null |
null |
{
"abstract": " Optical and near-infrared photometry, optical spectroscopy, and soft X-ray\nand UV monitoring of the changing look active galactic nucleus NGC 2617 show\nthat it continues to have the appearance of a type-1 Seyfert galaxy. An optical\nlight curve for 2010-2016 indicates that the change of type probably occurred\nbetween 2010 October and 2012 February and was not related to the brightening\nin 2013. In 2016 NGC 2617 brightened again to a level of activity close to that\nin 2013 April. We find variations in all passbands and in both the intensities\nand profiles of the broad Balmer lines. A new displaced emission peak has\nappeared in H$\\beta$. X-ray variations are well correlated with UV-optical\nvariability and possibly lead by $\\sim$ 2-3 d. The $K$ band lags the $J$ band\nby about 21.5 $\\pm$ 2.5 d. and lags the combined $B+J$ filters by $\\sim$ 25 d.\n$J$ lags $B$ by about 3 d. This could be because $J$-band variability arises\nfrom the outer part of the accretion disc, while $K$-band variability comes\nfrom thermal re-emission by dust. We propose that spectral-type changes are a\nresult of increasing central luminosity causing sublimation of the innermost\ndust in the hollow biconical outflow. We briefly discuss various other possible\nreasons that might explain the dramatic changes in NGC 2617.\n",
"title": "The curtain remains open: NGC 2617 continues in a high state"
}
| null | null | null | null | true | null |
11257
| null |
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| null | null |
null |
{
"abstract": " In this article, we give a full description of the topology of the one\ndimensional affine analytic space $\\mathbb{A}_R^1$ over a complete valuation\nring $R$ (i.e. a valuation ring with \"real valued valuation\" which is complete\nunder the induced metric), when its field of fractions $K$ is algebraically\nclosed. In particular, we show that $\\mathbb{A}_R^1$ is both connected and\nlocally path connected. Furthermore, $\\mathbb{A}_R^1$ is the completion of\n$K\\times (1,\\infty)$ under a canonical uniform structure. As an application, we\ndescribe the Berkovich spectrum $\\mathfrak{M}(\\mathbb{Z}_p[G])$ of the Banach\ngroup ring $\\mathbb{Z}_p[G]$ of a cyclic $p$-group $G$ over the ring\n$\\mathbb{Z}_p$ of $p$-adic integers.\n",
"title": "The topology on Berkovich affine lines over complete valuation rings"
}
| null | null | null | null | true | null |
11258
| null |
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| null | null |
null |
{
"abstract": " We suggest that ultra-high-energy (UHE) cosmic rays (CRs) may be accelerated\nin ultra-relativistic flows via a one-shot mechanism, the \"espresso\"\nacceleration, in which already-energetic particles are generally boosted by a\nfactor of $\\sim\\Gamma^2$ in energy, where $\\Gamma$ is the flow Lorentz factor.\nMore precisely, we consider blazar-like jets with $\\Gamma\\gtrsim 30$\npropagating into a halo of \"seed\" CRs produced in supernova remnants, which can\naccelerate UHECRs up to $10^{20}$\\,eV. Such a re-acceleration process naturally\naccounts for the chemical composition measured by the Pierre Auger\nCollaboration, which resembles the one around and above the knee in the CR\nspectrum, and is consistent with the distribution of potential sources in the\nlocal universe, particularly intriguing is the coincidence of the powerful\nblazar Mrk 421 with the hotspot reported by the Telescope Array Collaboration.\n",
"title": "An Original Mechanism for the Acceleration of Ultra-High-Energy Cosmic Rays"
}
| null | null | null | null | true | null |
11259
| null |
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| null | null |
null |
{
"abstract": " We study that the breakdown of epidemic depends on some parameters, that is\nexpressed in epidemic reproduction ratio number. It is noted that when $R_0 $\nexceeds 1, the stochastic model have two different results. But, eventually the\nextinction will be reached even though the major epidemic occurs. The question\nis how long this process will reach extinction. In this paper, we will focus on\nthe Markovian process of SIS model when major epidemic occurs. Using the\napproximation of quasi--stationary distribution, the expected mean time of\nextinction only occurs when the process is one step away from being extinct.\nCombining the theorm from Ethier and Kurtz, we use CLT to find the\napproximation of this quasi distribution and successfully determine the\nasymptotic mean time to extinction of SIS model without demography.\n",
"title": "Expected Time to Extinction of SIS Epidemic Model Using Quasy Stationary Distribution"
}
| null | null | null | null | true | null |
11260
| null |
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| null | null |
null |
{
"abstract": " We consider the asymptotics of large external magnetic field for a 2D\nVlasov-Poisson system governing the evolution of a bounded density interacting\nwith a point charge. In a suitable asymptotical regime, we show that the\nsolution converges to a measure-valued solution of the Euler equation with a\ndefect measure.\n",
"title": "The gyrokinetic limit for the Vlasov-Poisson system with a point charge"
}
| null | null | null | null | true | null |
11261
| null |
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| null | null |
null |
{
"abstract": " Hand-built verb clusters such as the widely used Levin classes (Levin, 1993)\nhave proved useful, but have limited coverage. Verb classes automatically\ninduced from corpus data such as those from VerbKB (Wijaya, 2016), on the other\nhand, can give clusters with much larger coverage, and can be adapted to\nspecific corpora such as Twitter. We present a method for clustering the\noutputs of VerbKB: verbs with their multiple argument types, e.g.\n\"marry(person, person)\", \"feel(person, emotion).\" We make use of a novel\nlow-dimensional embedding of verbs and their arguments to produce high quality\nclusters in which the same verb can be in different clusters depending on its\nargument type. The resulting verb clusters do a better job than hand-built\nclusters of predicting sarcasm, sentiment, and locus of control in tweets.\n",
"title": "Deriving Verb Predicates By Clustering Verbs with Arguments"
}
| null | null |
[
"Computer Science"
] | null | true | null |
11262
| null |
Validated
| null | null |
null |
{
"abstract": " The remoteness of the Sun and the harsh conditions prevailing in the solar\ncorona have so far limited the observational data used in the study of solar\nphysics to remote-sensing observations taken either from the ground or from\nspace. In contrast, the `solar wind laboratory' is directly measured in situ by\na fleet of spacecraft measuring the properties of the plasma and magnetic\nfields at specific points in space. Since 2007, the solar-terrestrial relations\nobservatory (STEREO) has been providing images of the solar wind that flows\nbetween the solar corona and spacecraft making in-situ measurements. This has\nallowed scientists to directly connect processes imaged near the Sun with the\nsubsequent effects measured in the solar wind. This new capability prompted the\ndevelopment of a series of tools and techniques to track heliospheric\nstructures through space. This article presents one of these tools, a web-based\ninterface called the 'Propagation Tool' that offers an integrated research\nenvironment to study the evolution of coronal and solar wind structures, such\nas Coronal Mass Ejections (CMEs), Corotating Interaction Regions (CIRs) and\nSolar Energetic Particles (SEPs). These structures can be propagated from the\nSun outwards to or alternatively inwards from planets and spacecraft situated\nin the inner and outer heliosphere. In this paper, we present the global\narchitecture of the tool, discuss some of the assumptions made to simulate the\nevolution of the structures and show how the tool connects to different\ndatabases.\n",
"title": "A propagation tool to connect remote-sensing observations with in-situ measurements of heliospheric structures"
}
| null | null | null | null | true | null |
11263
| null |
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| null | null |
null |
{
"abstract": " How atoms in covalent solids rearrange over a medium-range length-scale\nduring amorphization is a long pursued question whose answer could profoundly\nshape our understanding on amorphous (a-) networks. Based on ab-intio\ncalculations and reverse Monte Carlo simulations of experiments, we\nsurprisingly find that even though the severe chemical disorder in a-GeTe\nundermined the prevailing medium range order (MRO) picture, it is responsible\nfor the experimentally observed MRO. That this thing could happen depends on a\nnovel atomic packing scheme. And this scheme results in a kind of homopolar\nbond chain-like polyhedral clusters. Within this scheme, the formation of\nhomopolar bonds can be well explained by an electron-counting model and further\nvalidated by quantitative bond energy analysis based. Our study suggests that\nthe underlying physics for chemical disorder in a-GeTe is intrinsic and\nuniversal to all severely chemically disordered covalent glasses.\n",
"title": "Chemical-disorder-caused Medium Range Order in Covalent Glass"
}
| null | null | null | null | true | null |
11264
| null |
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| null | null |
null |
{
"abstract": " Models are often defined through conditional rather than joint distributions,\nbut it can be difficult to check whether the conditional distributions are\ncompatible, i.e. whether there exists a joint probability distribution which\ngenerates them. When they are compatible, a Gibbs sampler can be used to sample\nfrom this joint distribution. When they are not, the Gibbs sampling algorithm\nmay still be applied, resulting in a \"pseudo-Gibbs sampler\". We show its\nstationary probability distribution to be the optimal compromise between the\nconditional distributions, in the sense that it minimizes a mean squared misfit\nbetween them and its own conditional distributions. This allows us to perform\nObjective Bayesian analysis of correlation parameters in Kriging models by\nusing univariate conditional Jeffreys-rule posterior distributions instead of\nthe widely used multivariate Jeffreys-rule posterior. This strategy makes the\nfull-Bayesian procedure tractable. Numerical examples show it has near-optimal\nfrequentist performance in terms of prediction interval coverage.\n",
"title": "Optimal compromise between incompatible conditional probability distributions, with application to Objective Bayesian Kriging"
}
| null | null | null | null | true | null |
11265
| null |
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| null | null |
null |
{
"abstract": " Estimation of the intensity of a point process is considered within a\nnonparametric framework. The intensity measure is unknown and depends on\ncovariates, possibly many more than the observed number of jumps. Only a single\ntrajectory of the counting process is observed. Interest lies in estimating the\nintensity conditional on the covariates. The impact of the covariates is\nmodelled by an additive model where each component can be written as a linear\ncombination of possibly unknown functions. The focus is on prediction as\nopposed to variable screening. Conditions are imposed on the coefficients of\nthis linear combination in order to control the estimation error. The rates of\nconvergence are optimal when the number of active covariates is large. As an\napplication, the intensity of the buy and sell trades of the New Zealand dollar\nfutures is estimated and a test for forecast evaluation is presented. A\nsimulation is included to provide some finite sample intuition on the model and\nasymptotic properties.\n",
"title": "Estimation for the Prediction of Point Processes with Many Covariates"
}
| null | null | null | null | true | null |
11266
| null |
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| null | null |
null |
{
"abstract": " We consider a particular type of $\\sqrt{8/3}$-Liouville quantum gravity\nsurface called a doubly marked quantum disk (equivalently, a Brownian disk)\ndecorated by an independent chordal SLE$_6$ curve $\\eta$ between its marked\nboundary points. We obtain descriptions of the law of the quantum surfaces\nparameterized by the complementary connected components of $\\eta([0,t])$ for\neach time $t \\geq 0$ as well as the law of the left/right $\\sqrt{8/3}$-quantum\nboundary length process for $\\eta$.\n",
"title": "Chordal SLE$_6$ explorations of a quantum disk"
}
| null | null | null | null | true | null |
11267
| null |
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| null | null |
null |
{
"abstract": " We give new constructions of two classes of algebraic code families which are\nefficiently list decodable with small output list size from a fraction\n$1-R-\\epsilon$ of adversarial errors where $R$ is the rate of the code, for any\ndesired positive constant $\\epsilon$. The alphabet size depends only $\\epsilon$\nand is nearly-optimal.\nThe first class of codes are obtained by folding algebraic-geometric codes\nusing automorphisms of the underlying function field. The list decoding\nalgorithm is based on a linear-algebraic approach, which pins down the\ncandidate messages to a subspace with a nice \"periodic\" structure. The list is\npruned by precoding into a special form of \"subspace-evasive\" sets, which are\nconstructed pseudorandomly. Instantiating this construction with the\nGarcia-Stichtenoth function field tower yields codes list-decodable up to a\n$1-R-\\epsilon$ error fraction with list size bounded by $O(1/\\epsilon)$,\nmatching the existential bound up to constant factors. The parameters we\nachieve are thus quite close to the existential bounds in all three aspects:\nerror-correction radius, alphabet size, and list-size.\nThe second class of codes are obtained by restricting evaluation points of an\nalgebraic-geometric code to rational points from a subfield. Once again, the\nlinear-algebraic approach to list decoding to pin down candidate messages to a\nperiodic subspace. We develop an alternate approach based on \"subspace designs\"\nto precode messages. Together with the subsequent explicit constructions of\nsubspace designs, this yields a deterministic construction of an algebraic code\nfamily of rate $R$ with efficient list decoding from $1-R-\\epsilon$ fraction of\nerrors over a constant-sized alphabet. The list size is bounded by a very\nslowly growing function of the block length $N$; in particular, it is at most\n$O(\\log^{(r)} N)$ (the $r$'th iterated logarithm) for any fixed integer $r$.\n",
"title": "Optimal rate list decoding over bounded alphabets using algebraic-geometric codes"
}
| null | null | null | null | true | null |
11268
| null |
Default
| null | null |
null |
{
"abstract": " The paper investigates the problem of fitting protein complexes into electron\ndensity maps. They are represented by high-resolution cryoEM density maps\nconverted into overlapping matrices and partly show a structure of a complex.\nThe general purpose is to define positions of all proteins inside it. This\nproblem is known to be NP-hard, since it lays in the field of combinatorial\noptimization over a set of discrete states of the complex. We introduce\nquadratic programming approaches to the problem. To find an approximate\nsolution, we convert a density map into an overlapping matrix, which is\ngenerally indefinite. Since the matrix is indefinite, the optimization problem\nfor the corresponding quadratic form is non-convex. To treat non-convexity of\nthe optimization problem, we use different convex relaxations to find which set\nof proteins minimizes the quadratic form best.\n",
"title": "Quadratic Programming Approach to Fit Protein Complexes into Electron Density Maps"
}
| null | null |
[
"Mathematics"
] | null | true | null |
11269
| null |
Validated
| null | null |
null |
{
"abstract": " This paper provides a link between time-domain and frequency-domain stability\nresults in the literature. Specifically, we focus on the comparison between\nstability results for a feedback interconnection of two nonlinear systems\nstated in terms of frequency-domain conditions. While the Integral Quadratic\nConstrain (IQC) theorem can cope with them via a homotopy argument for the\nLurye problem, graph separation results require the transformation of the\nfrequency-domain conditions into truncated time-domain conditions. To date,\nmuch of the literature focuses on \"hard\" factorizations of the multiplier,\nconsidering only one of the two frequency-domain conditions. Here it is shown\nthat a symmetric, \"doubly-hard\" factorization is required to convert both\nfrequency-domain conditions into truncated time-domain conditions. By using the\nappropriate factorization, a novel comparison between the results obtained by\nIQC and separation theories is then provided. As a result, we identify under\nwhat conditions the IQC theorem may provide some advantage.\n",
"title": "Conditions for the equivalence between IQC and graph separation stability results"
}
| null | null | null | null | true | null |
11270
| null |
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| null | null |
null |
{
"abstract": " We propose an intelligent proactive content caching scheme to reduce the\nenergy consumption in wireless downlink. We consider an online social network\n(OSN) setting where new contents are generated over time, and remain\n\\textit{relevant} to the user for a random lifetime. Contents are downloaded to\nthe user equipment (UE) through a time-varying wireless channel at an energy\ncost that depends on the channel state and the number of contents downloaded.\nThe user accesses the OSN at random time instants, and consumes all the\nrelevant contents. To reduce the energy consumption, we propose\n\\textit{proactive caching} of contents under favorable channel conditions to a\nfinite capacity cache memory. Assuming that the channel quality (or\nequivalently, the cost of downloading data) is memoryless over time slots, we\nshow that the optimal caching policy, which may replace contents in the cache\nwith shorter remaining lifetime with contents at the server that remain\nrelevant longer, has certain threshold structure with respect to the channel\nquality. Since the optimal policy is computationally demanding in practice, we\nintroduce a simplified caching scheme and optimize its parameters using policy\nsearch. We also present two lower bounds on the energy consumption. We\ndemonstrate through numerical simulations that the proposed caching scheme\nsignificantly reduces the energy consumption compared to traditional reactive\ncaching tools, and achieves close-to-optimal performance for a wide variety of\nsystem parameters.\n",
"title": "Energy-Efficient Wireless Content Delivery with Proactive Caching"
}
| null | null | null | null | true | null |
11271
| null |
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| null | null |
null |
{
"abstract": " The Juno Orbiter has provided improved estimates of the even gravitational\nharmonics J2 to J8 of Jupiter. To compute higher-order moments, new methods\nsuch as the Concentric Maclaurin Spheroids (CMS) method have been developed\nwhich surpass the so far commonly used Theory of Figures (ToF) method in\naccuracy. This progress rises the question whether ToF can still provide a\nuseful service for deriving the internal structure of giant planets in the\nSolar system. In this paper, I apply both the ToF and the CMS method to compare\nresults for polytropic Jupiter and for the physical equation of state\nH/He-REOS.3 based models. An accuracy in the computed values of J2 and J4 of\n0.1% is found to be sufficient in order to obtain the core mass safely within\n0.5 Mearth numerical accuracy and the atmospheric metallicity within about\n0.0004. ToF to 4th order provides that accuracy, while ToF to 3rd order does\nnot for J4. Furthermore, I find that the assumption of rigid rotation yields J6\nand J8 values in agreement with the current Juno estimates, and that higher\norder terms (J10 to J18) deviate by about 10% from predictions by polytropic\nmodels. This work suggests that ToF4 can still be applied to infer the deep\ninternal structure, and that the zonal winds on Jupiter reach less deep than\n0.9 RJup.\n",
"title": "Low- and high-order gravitational harmonics of rigidly rotating Jupiter"
}
| null | null |
[
"Physics"
] | null | true | null |
11272
| null |
Validated
| null | null |
null |
{
"abstract": " Generative Adversarial Networks (GANs) have been promising in the field of\nimage generation, however, they have been hard to train for language\ngeneration. GANs were originally designed to output differentiable values, so\ndiscrete language generation is challenging for them which causes high levels\nof instability in training GANs. Consequently, past work has resorted to\npre-training with maximum-likelihood or training GANs without pre-training with\na WGAN objective with a gradient penalty. In this study, we present a\ncomparison of those approaches. Furthermore, we present the results of some\nexperiments that indicate better training and convergence of Wasserstein GANs\n(WGANs) when a weaker regularization term is enforcing the Lipschitz\nconstraint.\n",
"title": "Language Modeling with Generative Adversarial Networks"
}
| null | null | null | null | true | null |
11273
| null |
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| null | null |
null |
{
"abstract": " A characteristic feature of differential-algebraic equations is that one\nneeds to find derivatives of some of their equations with respect to time, as\npart of so called index reduction or regularisation, to prepare them for\nnumerical solution. This is often done with the help of a computer algebra\nsystem. We show in two significant cases that it can be done efficiently by\npure algorithmic differentiation. The first is the Dummy Derivatives method,\nhere we give a mainly theoretical description, with tutorial examples. The\nsecond is the solution of a mechanical system directly from its Lagrangian\nformulation. Here we outline the theory and show several non-trivial examples\nof using the \"Lagrangian facility\" of the Nedialkov-Pryce initial-value solver\nDAETS, namely: a spring-mass-multipendulum system, a prescribed-trajectory\ncontrol problem, and long-time integration of a model of the outer planets of\nthe solar system, taken from the DETEST testing package for ODE solvers.\n",
"title": "How AD Can Help Solve Differential-Algebraic Equations"
}
| null | null |
[
"Mathematics"
] | null | true | null |
11274
| null |
Validated
| null | null |
null |
{
"abstract": " Java platform and third-party libraries provide various security features to\nfacilitate secure coding. However, misusing these features can cost tremendous\ntime and effort of developers or cause security vulnerabilities in software.\nPrior research was focused on the misuse of cryptography and SSL APIs, but did\nnot explore the key fundamental research question: what are the biggest\nchallenges and vulnerabilities in secure coding practices? In this paper, we\nconducted a comprehensive empirical study on StackOverflow posts to understand\ndevelopers' concerns on Java secure coding, their programming obstacles, and\npotential vulnerabilities in their code. We observed that developers have\nshifted their effort to the usage of authentication and authorization features\nprovided by Spring security--a third-party framework designed to secure\nenterprise applications. Multiple programming challenges are related to APIs or\nlibraries, including the complicated cross-language data handling of\ncryptography APIs, and the complex Java-based or XML-based approaches to\nconfigure Spring security. More interestingly, we identified security\nvulnerabilities in the suggested code of accepted answers. The vulnerabilities\nincluded using insecure hash functions such as MD5, breaking SSL/TLS security\nthrough bypassing certificate validation, and insecurely disabling the default\nprotection against Cross Site Request Forgery (CSRF) attacks. Our findings\nreveal the insufficiency of secure coding assistance and education, and the gap\nbetween security theory and coding practices.\n",
"title": "Secure Coding Practices in Java: Challenges and Vulnerabilities"
}
| null | null |
[
"Computer Science"
] | null | true | null |
11275
| null |
Validated
| null | null |
null |
{
"abstract": " This paper presents a Light Detection and Ranging (LiDAR) data set that\ntargets complex urban environments. Urban environments with high-rise buildings\nand congested traffic pose a significant challenge for many robotics\napplications. The presented data set is unique in the sense it is able to\ncapture the genuine features of an urban environment (e.g. metropolitan areas,\nlarge building complexes and underground parking lots). Data of two-dimensional\n(2D) and threedimensional (3D) LiDAR, which are typical types of LiDAR sensors,\nare provided in the data set. The two 16-ray 3D LiDARs are tilted on both sides\nfor maximal coverage. One 2D LiDAR faces backward while the other faces\nforwards to collect data of roads and buildings, respectively. Raw sensor data\nfrom Fiber Optic Gyro (FOG), Inertial Measurement Unit (IMU), and the Global\nPositioning System (GPS) are presented in a file format for vehicle pose\nestimation. The pose information of the vehicle estimated at 100 Hz is also\npresented after applying the graph simultaneous localization and mapping (SLAM)\nalgorithm. For the convenience of development, the file player and data viewer\nin Robot Operating System (ROS) environment were also released via the web\npage. The full data sets are available at: this http URL. In\nthis website, 3D preview of each data set is provided using WebGL.\n",
"title": "Complex Urban LiDAR Data Set"
}
| null | null | null | null | true | null |
11276
| null |
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| null | null |
null |
{
"abstract": " We propose a new blind source separation algorithm based on mixtures of\nalpha-stable distributions. Complex symmetric alpha-stable distributions have\nbeen recently showed to better model audio signals in the time-frequency domain\nthan classical Gaussian distributions thanks to their larger dynamic range.\nHowever, inference of these models is notoriously hard to perform because their\nprobability density functions do not have a closed-form expression in general.\nHere, we introduce a novel method for estimating mixture of alpha-stable\ndistributions based on characteristic function matching. We apply this to the\nblind estimation of binary masks in individual frequency bands from\nmultichannel convolutive audio mixes. We show that the proposed method yields\nbetter separation performance than Gaussian-based binary-masking methods.\n",
"title": "Blind Source Separation Using Mixtures of Alpha-Stable Distributions"
}
| null | null | null | null | true | null |
11277
| null |
Default
| null | null |
null |
{
"abstract": " Upper-division physics students spend much of their time solving problems. In\naddition to their basic skills and background, their epistemic framing can form\nan important part of their ability to learn physics from these problems.\nEncouraging students to move toward productive framing may help them solve\nproblems. Thus, an instructor should understand the specifics of how student\nhave framed a problem and understand how her interaction with the students will\nimpact that framing. In this study we investigate epistemic framing of students\nin problem solving situations where math is applied to physics. To analyze the\nframes and changes in frames, we develop and use a two-axis framework involving\nconceptual and algorithmic physics and math. We examine student and instructor\nframing and the interactions of these frames over a range of problems in an\nupper-division electromagnetic fields course. Within interactions, students and\ninstructors generally follow each others' leads in framing.\n",
"title": "Student and instructor framing in upper-division physics"
}
| null | null | null | null | true | null |
11278
| null |
Default
| null | null |
null |
{
"abstract": " Accurate and automated detection of anomalous samples in a natural image\ndataset can be accomplished with a probabilistic model for end-to-end modeling\nof images. Such images have heterogeneous complexity, however, and a\nprobabilistic model overlooks simply shaped objects with small anomalies. This\nis because the probabilistic model assigns undesirably lower likelihoods to\ncomplexly shaped objects that are nevertheless consistent with set standards.\nTo overcome this difficulty, we propose an unregularized score for deep\ngenerative models (DGMs), which are generative models leveraging deep neural\nnetworks. We found that the regularization terms of the DGMs considerably\ninfluence the anomaly score depending on the complexity of the samples. By\nremoving these terms, we obtain an unregularized score, which we evaluated on a\ntoy dataset and real-world manufacturing datasets. Empirical results\ndemonstrate that the unregularized score is robust to the inherent complexity\nof samples and can be used to better detect anomalies.\n",
"title": "Deep Generative Model using Unregularized Score for Anomaly Detection with Heterogeneous Complexity"
}
| null | null | null | null | true | null |
11279
| null |
Default
| null | null |
null |
{
"abstract": " The magnetic properties of the pyrochlore iridate material Eu$_2$Ir$_2$O$_7$\n(5$d^5$) have been studied based on the first principle calculations, where the\ncrystal field splitting $\\Delta$, spin-orbit coupling (SOC) $\\lambda$ and\nCoulomb interaction $U$ within Ir 5$d$ orbitals are all playing significant\nroles. The ground state phase diagram has been obtained with respect to the\nstrength of SOC and Coulomb interaction $U$, where a stable anti-ferromagnetic\nground state with all-in/all-out (AIAO) spin structure has been found. Besides,\nanother anti-ferromagnetic states with close energy to AIAO have also been\nfound to be stable. The calculated nonlinear magnetization of the two stable\nstates both have the d-wave pattern but with a $\\pi/4$ phase difference, which\ncan perfectly explain the experimentally observed nonlinear magnetization\npattern. Compared with the results of the non-distorted structure, it turns out\nthat the trigonal lattice distortion is crucial for stabilizing the AIAO state\nin Eu$_2$Ir$_2$O$_7$. Furthermore, besides large dipolar moments, we also find\nconsiderable octupolar moments in the magnetic states.\n",
"title": "Non-collinear magnetic structure and multipolar order in Eu$_2$Ir$_2$O$_7$"
}
| null | null | null | null | true | null |
11280
| null |
Default
| null | null |
null |
{
"abstract": " We report the discovery and the analysis of the planetary microlensing event,\nOGLE-2013-BLG-1761. There are some degenerate solutions in this event because\nthe planetary anomaly is only sparsely sampled. But the detailed light curve\nanalysis ruled out all stellar binary models and shows that the lens to be a\nplanetary system. There is the so-called close/wide degeneracy in the solutions\nwith the planet/host mass ratio of $q \\sim (7.5 \\pm 1.5) \\times 10^{-3}$ and $q\n\\sim (9.3 \\pm 2.9) \\times 10^{-3}$ with the projected separation in Einstein\nradius units of $s = 0.95$ (close) and $s = 1.19$ (wide), respectively. The\nmicrolens parallax effect is not detected but the finite source effect is\ndetected. Our Bayesian analysis indicates that the lens system is located at\n$D_{\\rm L}=6.9_{-1.2}^{+1.0} \\ {\\rm kpc}$ away from us and the host star is an\nM/K-dwarf with the mass of $M_{\\rm L}=0.33_{-0.18}^{+0.32} \\ M_{\\odot}$ orbited\nby a super-Jupiter mass planet with the mass of $m_{\\rm P}=2.8_{-1.5}^{+2.5} \\\nM_{\\rm Jup}$ at the projected separation of $a_{\\perp}=1.8_{-0.5}^{+0.5} \\ {\\rm\nAU}$. The preference of the large lens distance in the Bayesian analysis is due\nto the relatively large observed source star radius. The distance and other\nphysical parameters can be constrained by the future high resolution imaging by\nground large telescopes or HST. If the estimated lens distance is correct, this\nplanet provides another sample for testing the claimed deficit of planets in\nthe Galactic bulge.\n",
"title": "OGLE-2013-BLG-1761Lb: A Massive Planet Around an M/K Dwarf"
}
| null | null | null | null | true | null |
11281
| null |
Default
| null | null |
null |
{
"abstract": " We present a single-channel phase-sensitive speech enhancement algorithm that\nis based on modulation-domain Kalman filtering and on tracking the speech phase\nusing circular statistics. With Kalman filtering, using that speech and noise\nare additive in the complex STFT domain, the algorithm tracks the speech\nlog-spectrum, the noise log-spectrum and the speech phase. Joint amplitude and\nphase estimation of speech is performed. Given the noisy speech signal,\nconventional algorithms use the noisy phase for signal reconstruction\napproximating the speech phase with the noisy phase. In the proposed Kalman\nfiltering algorithm, the speech phase posterior is used to create an enhanced\nspeech phase spectrum for signal reconstruction. The Kalman filter prediction\nmodels the temporal/inter-frame correlation of the speech and noise log-spectra\nand of the speech phase, while the Kalman filter update models their nonlinear\nrelations. With the proposed algorithm, speech is tracked and estimated both in\nthe log-spectral and spectral phase domains. The algorithm is evaluated in\nterms of speech quality and different algorithm configurations, dependent on\nthe signal model, are compared in different noise types. Experimental results\nshow that the proposed algorithm outperforms traditional enhancement algorithms\nover a range of SNRs for various noise types.\n",
"title": "Phase-Aware Single-Channel Speech Enhancement with Modulation-Domain Kalman Filtering"
}
| null | null |
[
"Computer Science"
] | null | true | null |
11282
| null |
Validated
| null | null |
null |
{
"abstract": " For a monic polynomial $D(X)$ of even degree, express $\\sqrt D$ as a Laurent\nseries in $X^{-1}$; this yields a continued fraction expansion (similar to\ncontinued fractions of real numbers): \\[\\sqrt\nD=a_0+\\dfrac{1}{a_1+\\dfrac{1}{a_2+\\dfrac{1}{\\ddots}}},\\quad a_i\\text{\npolynomials in }X.\\] Such continued fractions were first considered by Abel in\n1826, and later by Chebyshev. It turns out they are rarely periodic unless $D$\nis defined over a finite field.\nAround 2001 van der Poorten studied non-periodic continued fractions of\n$\\sqrt D$, with $D$ defined over the rationals, and simultaneously the\ncontinued fraction of $\\sqrt D$ modulo a suitable prime $p$; the latter\ncontinued fraction is automatically periodic. He found that one recovers all\nthe convergents (rational function approximations to $\\sqrt D$ obtained by\ncutting off the continued fraction) of $\\sqrt D \\mod{p}$ by appropriately\nnormalising and then reducing the convergents of $\\sqrt D$.\nBy developing a general specialization theory for continued fractions of\nLaurent series, I produced a rigorous proof of this result stated by van der\nPoorten and further was able to show the following:\nIf $D$ is defined over the rationals and the continued fraction of $\\sqrt D$\nis non-periodic, then for all but finitely many primes $p \\in \\mathbb Z$, this\nprime $p$ occurs in the denominator of the leading coefficient of infinitely\nmany $a_i$.\nFor $\\mathrm{deg}\\,D = 4$, I can even give a description of the orders in\nwhich the prime appears, and the $p$-adic Gauss norms of the $a_i$ and the\nconvergents. These results also generalise to number fields.\nMoreover, I derive optimised formulae for computing quadratic continued\nfractions, along with several example expansions. I discuss a few known results\non the heights of the convergents, and explain some relations with the\nreduction of hyperelliptic curves and Jacobians.\n",
"title": "Reduction and specialization of hyperelliptic continued fractions"
}
| null | null | null | null | true | null |
11283
| null |
Default
| null | null |
null |
{
"abstract": " Spatially resolving the immediate surroundings of young stars is a key\nchallenge for the planet formation community. SPHERE on the VLT represents an\nimportant step forward by increasing the opportunities offered by optical or\nnear-infrared imaging instruments to image protoplanetary discs. The Guaranteed\nTime Observation Disc team has concentrated much of its efforts on polarimetric\ndifferential imaging, a technique that enables the efficient removal of stellar\nlight and thus facilitates the detection of light scattered by the disc within\na few au from the central star. These images reveal intriguing complex disc\nstructures and diverse morphological features that are possibly caused by\nongoing planet formation in the disc. An overview of the recent advances\nenabled by SPHERE is presented.\n",
"title": "Three years of SPHERE: the latest view of the morphology and evolution of protoplanetary discs"
}
| null | null | null | null | true | null |
11284
| null |
Default
| null | null |
null |
{
"abstract": " In the low rank matrix completion (LRMC) problem, the low rank assumption\nmeans that the columns (or rows) of the matrix to be completed are points on a\nlow-dimensional linear algebraic variety. This paper extends this thinking to\ncases where the columns are points on a low-dimensional nonlinear algebraic\nvariety, a problem we call Low Algebraic Dimension Matrix Completion (LADMC).\nMatrices whose columns belong to a union of subspaces (UoS) are an important\nspecial case. We propose a LADMC algorithm that leverages existing LRMC methods\non a tensorized representation of the data. For example, a second-order\ntensorization representation is formed by taking the outer product of each\ncolumn with itself, and we consider higher order tensorizations as well. This\napproach will succeed in many cases where traditional LRMC is guaranteed to\nfail because the data are low-rank in the tensorized representation but not in\nthe original representation. We also provide a formal mathematical\njustification for the success of our method. In particular, we show bounds of\nthe rank of these data in the tensorized representation, and we prove sampling\nrequirements to guarantee uniqueness of the solution. Interestingly, the\nsampling requirements of our LADMC algorithm nearly match the information\ntheoretic lower bounds for matrix completion under a UoS model. We also provide\nexperimental results showing that the new approach significantly outperforms\nexisting state-of-the-art methods for matrix completion in many situations.\n",
"title": "Tensor Methods for Nonlinear Matrix Completion"
}
| null | null | null | null | true | null |
11285
| null |
Default
| null | null |
null |
{
"abstract": " From just a glance, humans can make rich predictions about the future state\nof a wide range of physical systems. On the other hand, modern approaches from\nengineering, robotics, and graphics are often restricted to narrow domains and\nrequire direct measurements of the underlying states. We introduce the Visual\nInteraction Network, a general-purpose model for learning the dynamics of a\nphysical system from raw visual observations. Our model consists of a\nperceptual front-end based on convolutional neural networks and a dynamics\npredictor based on interaction networks. Through joint training, the perceptual\nfront-end learns to parse a dynamic visual scene into a set of factored latent\nobject representations. The dynamics predictor learns to roll these states\nforward in time by computing their interactions and dynamics, producing a\npredicted physical trajectory of arbitrary length. We found that from just six\ninput video frames the Visual Interaction Network can generate accurate future\ntrajectories of hundreds of time steps on a wide range of physical systems. Our\nmodel can also be applied to scenes with invisible objects, inferring their\nfuture states from their effects on the visible objects, and can implicitly\ninfer the unknown mass of objects. Our results demonstrate that the perceptual\nmodule and the object-based dynamics predictor module can induce factored\nlatent representations that support accurate dynamical predictions. This work\nopens new opportunities for model-based decision-making and planning from raw\nsensory observations in complex physical environments.\n",
"title": "Visual Interaction Networks"
}
| null | null |
[
"Computer Science"
] | null | true | null |
11286
| null |
Validated
| null | null |
null |
{
"abstract": " Context. Clouds have already been detected in exoplanetary atmospheres. They\nplay crucial roles in a planet's atmosphere and climate and can also create\nambiguities in the determination of atmospheric parameters such as trace gas\nmixing ratios. Knowledge of cloud properties is required when assessing the\nhabitability of a planet. Aims. We aim to show that various types of cloud\ncover such as polar cusps, subsolar clouds, and patchy clouds on Earth-like\nexoplanets can be distinguished from each other using the polarization and flux\nof light that is reflected by the planet. Methods. We have computed the flux\nand polarization of reflected starlight for different types of (liquid water)\ncloud covers on Earth-like model planets using the adding-doubling method, that\nfully includes multiple scattering and polarization. Variations in cloud-top\naltitudes and planet-wide cloud cover percentages were taken into account.\nResults. We find that the different types of cloud cover (polar cusps, subsolar\nclouds, and patchy clouds) can be distinguished from each other and that the\npercentage of cloud cover can be estimated within 10%. Conclusions. Using our\nproposed observational strategy, one should be able to determine basic orbital\nparameters of a planet such as orbital inclination and estimate cloud coverage\nwith reduced ambiguities from the planet's polarization signals along its\norbit.\n",
"title": "Using polarimetry to retrieve the cloud coverage of Earth-like exoplanets"
}
| null | null | null | null | true | null |
11287
| null |
Default
| null | null |
null |
{
"abstract": " We have found Dirac nodal lines (DNLs) in the band structures of metallic\nrutile oxides IrO$_2$, OsO$_2$, and RuO$_2$ and revealed a large spin Hall\nconductivity contributed by these nodal lines, which explains a strong spin\nHall effect (SHE) of IrO$_2$ discovered recently. Two types of DNLs exist. The\nfirst type forms DNL networks that extend in the whole Brillouin zone and\nappears only in the absence of spin-orbit coupling (SOC), which induces surface\nstates on the boundary. Because of SOC-induced band anti-crossing, a large\nintrinsic SHE can be realized in these compounds. The second type appears at\nthe Brillouin zone edges and is stable against SOC because of the protection of\nnonsymmorphic symmetry. Besides reporting new DNL materials, our work reveals\nthe general relationship between DNLs and the SHE, indicating a way to apply\nDirac nodal materials for spintronics.\n",
"title": "Dirac nodal lines and induced spin Hall effect in metallic rutile oxides"
}
| null | null | null | null | true | null |
11288
| null |
Default
| null | null |
null |
{
"abstract": " Hair cells of the auditory and vestibular systems are capable of detecting\nsounds that induce sub-nanometer vibrations of the hair bundle, below the\nstochastic noise levels of the surrounding fluid. Hair cells of certain species\nare also known to oscillate without external stimulation, indicating the\npresence of an underlying active mechanism. We previously demonstrated that\nthese spontaneous oscillations exhibit chaotic dynamics. By varying the Calcium\nconcentration and the viscosity of the Endolymph solution, we are able to\nmodulate the degree of chaos in the hair cell dynamics. We find that the hair\ncell is most sensitive to a stimulus of small amplitude when it is poised in\nthe weakly chaotic regime. Further, we show that the response time to a force\nstep decreases with increasing levels of chaos. These results agree well with\nour numerical simulations of a chaotic Hopf oscillator and suggest that chaos\nmay be responsible for the extreme sensitivity and temporal resolution of hair\ncells.\n",
"title": "Chaotic Dynamics Enhance the Sensitivity of Inner Ear Hair Cells"
}
| null | null | null | null | true | null |
11289
| null |
Default
| null | null |
null |
{
"abstract": " External localization is an essential part for the indoor operation of small\nor cost-efficient robots, as they are used, for example, in swarm robotics. We\nintroduce a two-stage localization and instance identification framework for\narbitrary robots based on convolutional neural networks. Object detection is\nperformed on an external camera image of the operation zone providing robot\nbounding boxes for an identification and orientation estimation convolutional\nneural network. Additionally, we propose a process to generate the necessary\ntraining data. The framework was evaluated with 3 different robot types and\nvarious identification patterns. We have analyzed the main framework\nhyperparameters providing recommendations for the framework operation settings.\nWe achieved up to 98% [email protected] and only 1.6° orientation error, running\nwith a frame rate of 50 Hz on a GPU.\n",
"title": "A Robot Localization Framework Using CNNs for Object Detection and Pose Estimation"
}
| null | null | null | null | true | null |
11290
| null |
Default
| null | null |
null |
{
"abstract": " Natural language elements, e.g., todo comments, are frequently used to\ncommunicate among the developers and to describe tasks that need to be\nperformed (actions) when specific conditions hold in the code repository\n(triggers). As projects evolve, development processes change, and development\nteams reorganize, these comments, because of their informal nature, frequently\nbecome irrelevant or forgotten.\nWe present the first technique, dubbed TrigIt, to specify triggeraction todo\ncomments as executable statements. Thus, actions are executed automatically\nwhen triggers evaluate to true. TrigIt specifications are written in the host\nlanguage (e.g., Java) and are evaluated as part of the build process. The\ntriggers are specified as query statements over abstract syntax trees and\nabstract representation of build configuration scripts, and the actions are\nspecified as code transformation steps. We implemented TrigIt for the Java\nprogramming language and migrated 20 existing trigger-action comments from 8\npopular open-source projects. We evaluate the cost of using TrigIt in terms of\nthe number of tokens in the executable comments and the time overhead\nintroduced in the build process.\n",
"title": "Executable Trigger-Action Comments"
}
| null | null | null | null | true | null |
11291
| null |
Default
| null | null |
null |
{
"abstract": " Information extraction (IE) from text has largely focused on relations\nbetween individual entities, such as who has won which award. However, some\nfacts are never fully mentioned, and no IE method has perfect recall. Thus, it\nis beneficial to also tap contents about the cardinalities of these relations,\nfor example, how many awards someone has won. We introduce this novel problem\nof extracting cardinalities and discusses the specific challenges that set it\napart from standard IE. We present a distant supervision method using\nconditional random fields. A preliminary evaluation results in precision\nbetween 3% and 55%, depending on the difficulty of relations.\n",
"title": "Cardinal Virtues: Extracting Relation Cardinalities from Text"
}
| null | null | null | null | true | null |
11292
| null |
Default
| null | null |
null |
{
"abstract": " Domestic violence (DV) is a global social and public health issue that is\nhighly gendered. Being able to accurately predict DV recidivism, i.e.,\nre-offending of a previously convicted offender, can speed up and improve risk\nassessment procedures for police and front-line agencies, better protect\nvictims of DV, and potentially prevent future re-occurrences of DV. Previous\nwork in DV recidivism has employed different classification techniques,\nincluding decision tree (DT) induction and logistic regression, where the main\nfocus was on achieving high prediction accuracy. As a result, even the diagrams\nof trained DTs were often too difficult to interpret due to their size and\ncomplexity, making decision-making challenging. Given there is often a\ntrade-off between model accuracy and interpretability, in this work our aim is\nto employ DT induction to obtain both interpretable trees as well as high\nprediction accuracy. Specifically, we implement and evaluate different\napproaches to deal with class imbalance as well as feature selection. Compared\nto previous work in DV recidivism prediction that employed logistic regression,\nour approach can achieve comparable area under the ROC curve results by using\nonly 3 of 11 available features and generating understandable decision trees\nthat contain only 4 leaf nodes.\n",
"title": "A Decision Tree Approach to Predicting Recidivism in Domestic Violence"
}
| null | null |
[
"Statistics"
] | null | true | null |
11293
| null |
Validated
| null | null |
null |
{
"abstract": " We provide numerical evidence demonstrating the necessity of employing a\nsuperparametric geometry representation in order to obtain optimal convergence\norders on two-dimensional domains with curved boundaries when solving the Euler\nequations using Discontinuous Galerkin methods. However, concerning the\nobtention of optimal convergence orders for the Navier-Stokes equations, we\ndemonstrate numerically that the use of isoparametric geometry representation\nis sufficient for the case considered here.\n",
"title": "On the Necessity of Superparametric Geometry Representation for Discontinuous Galerkin Methods on Domains with Curved Boundaries"
}
| null | null | null | null | true | null |
11294
| null |
Default
| null | null |
null |
{
"abstract": " Electron ptychography has seen a recent surge of interest for phase sensitive\nimaging at atomic or near-atomic resolution. However, applications are so far\nmainly limited to radiation-hard samples because the required doses are too\nhigh for imaging biological samples at high resolution. We propose the use of\nnon-convex, Bayesian optimization to overcome this problem and reduce the dose\nrequired for successful reconstruction by two orders of magnitude compared to\nprevious experiments. We suggest to use this method for imaging single\nbiological macromolecules at cryogenic temperatures and demonstrate 2D\nsingle-particle reconstructions from simulated data with a resolution of 7.9\n\\AA$\\,$ at a dose of 20 $e^- / \\AA^2$. When averaging over only 15 low-dose\ndatasets, a resolution of 4 \\AA$\\,$ is possible for large macromolecular\ncomplexes. With its independence from microscope transfer function, direct\nrecovery of phase contrast and better scaling of signal-to-noise ratio,\ncryo-electron ptychography may become a promising alternative to Zernike\nphase-contrast microscopy.\n",
"title": "Low-dose cryo electron ptychography via non-convex Bayesian optimization"
}
| null | null | null | null | true | null |
11295
| null |
Default
| null | null |
null |
{
"abstract": " We have modeled laser-induced transient current waveforms in radiation\ncoplanar grid detectors. Poisson's equation has been solved by finite element\nmethod and currents induced by photo-generated charge were obtained using\nShockley-Ramo theorem. The spectral response on a radiation flux has been\nmodeled by Monte-Carlo simulations. We show 10$\\times$ improved spectral\nresolution of coplanar grid detector using differential signal sensing. We\nmodel the current waveform dependence on doping, depletion width, diffusion and\ndetector shielding and their mutual dependence is discussed in terms of\ndetector optimization. The numerical simulations are successfully compared to\nexperimental data and further model simplifications are proposed. The space\ncharge below electrodes and a non-homogeneous electric field on a coplanar grid\nanode are found to be the dominant contributions to laser-induced transient\ncurrent waveforms.\n",
"title": "Efficient Charge Collection in Coplanar Grid Radiation Detectors"
}
| null | null | null | null | true | null |
11296
| null |
Default
| null | null |
null |
{
"abstract": " Isolated quantum many-body systems with integrable dynamics generically do\nnot thermalize when taken far from equilibrium. As one perturbs such systems\naway from the integrable point, thermalization sets in, but the nature of the\ncrossover from integrable to thermalizing behavior is an unresolved and\nactively discussed question. We explore this question by studying the dynamics\nof the momentum distribution function in a dipolar quantum Newton's cradle\nconsisting of highly magnetic dysprosium atoms. This is accomplished by\ncreating the first one-dimensional Bose gas with strong magnetic dipole-dipole\ninteractions. These interactions provide tunability of both the strength of the\nintegrability-breaking perturbation and the nature of the near-integrable\ndynamics. We provide the first experimental evidence that thermalization close\nto a strongly interacting integrable point occurs in two steps:\nprethermalization followed by near-exponential thermalization. Exact numerical\ncalculations on a two-rung lattice model yield a similar two-timescale process,\nsuggesting that this is generic in strongly interacting near-integrable models.\nMoreover, the measured thermalization rate is consistent with a parameter-free\ntheoretical estimate, based on identifying the types of collisions that\ndominate thermalization. By providing tunability between regimes of integrable\nand nonintegrable dynamics, our work sheds light both on the mechanisms by\nwhich isolated quantum many-body systems thermalize, and on the temporal\nstructure of the onset of thermalization.\n",
"title": "Thermalization near integrability in a dipolar quantum Newton's cradle"
}
| null | null |
[
"Physics"
] | null | true | null |
11297
| null |
Validated
| null | null |
null |
{
"abstract": " We first consider the additive Brownian motion process $(X(s_1,s_2),\\\n(s_1,s_2) \\in \\mathbb{R}^2)$ defined by $X(s_1,s_2) = Z_1(s_1) - Z_2 (s_2)$,\nwhere $Z_1$ and $Z_2 $ are two independent (two-sided) Brownian motions. We\nshow that with probability one, the Hausdorff dimension of the boundary of any\nconnected component of the random set $\\{(s_1,s_2)\\in \\mathbb{R}^2: X(s_1,s_2)\n>0\\}$ is equal to $$\n\\frac{1}{4}\\left(1 + \\sqrt{13 + 4 \\sqrt{5}}\\right) \\simeq 1.421\\, . $$ Then\nthe same result is shown to hold when $X$ is replaced by a standard Brownian\nsheet indexed by the nonnegative quadrant.\n",
"title": "Hausdorff dimension of the boundary of bubbles of additive Brownian motion and of the Brownian sheet"
}
| null | null | null | null | true | null |
11298
| null |
Default
| null | null |
null |
{
"abstract": " In this paper we complete the study started in [Pi2] of evolution by inverse\nmean curvature flow of star-shaped hypersurface in non-compact rank one\nsymmetric spaces. We consider the evolution by inverse mean curvature flow of a\nclosed, mean convex and star-shaped hypersurface in the quaternionic hyperbolic\nspace. We prove that the flow is defined for any positive time, the evolving\nhypersurface stays star-shaped and mean convex. Moreover the induced metric\nconverges, after rescaling, to a conformal multiple of the standard\nsub-Riemannian metric on the sphere defined on a codimension 3 distribution.\nFinally we show that there exists a family of examples such that the qc-scalar\ncurvature of this sub-Riemannian limit is not constant.\n",
"title": "Inverse mean curvature flow in quaternionic hyperbolic space"
}
| null | null |
[
"Mathematics"
] | null | true | null |
11299
| null |
Validated
| null | null |
null |
{
"abstract": " Mosquitoes are a major vector for malaria, causing hundreds of thousands of\ndeaths in the developing world each year. Not only is the prevention of\nmosquito bites of paramount importance to the reduction of malaria transmission\ncases, but understanding in more forensic detail the interplay between malaria,\nmosquito vectors, vegetation, standing water and human populations is crucial\nto the deployment of more effective interventions. Typically the presence and\ndetection of malaria-vectoring mosquitoes is only quantified by hand-operated\ninsect traps or signified by the diagnosis of malaria. If we are to gather\ntimely, large-scale data to improve this situation, we need to automate the\nprocess of mosquito detection and classification as much as possible. In this\npaper, we present a candidate mobile sensing system that acts as both a\nportable early warning device and an automatic acoustic data acquisition\npipeline to help fuel scientific inquiry and policy. The machine learning\nalgorithm that powers the mobile system achieves excellent off-line\nmulti-species detection performance while remaining computationally efficient.\nFurther, we have conducted preliminary live mosquito detection tests using\nlow-cost mobile phones and achieved promising results. The deployment of this\nsystem for field usage in Southeast Asia and Africa is planned in the near\nfuture. In order to accelerate processing of field recordings and labelling of\ncollected data, we employ a citizen science platform in conjunction with\nautomated methods, the former implemented using the Zooniverse platform,\nallowing crowdsourcing on a grand scale.\n",
"title": "Mosquito detection with low-cost smartphones: data acquisition for malaria research"
}
| null | null | null | null | true | null |
11300
| null |
Default
| null | null |
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