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null | inputs
dict | prediction
null | prediction_agent
null | annotation
list | annotation_agent
null | multi_label
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class | explanation
null | id
stringlengths 1
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{
"abstract": " This work is the first step towards a description of the Gromov boundary of\nthe free factor graph of a free product, with applications to subgroup\nclassification for outer automorphisms. We extend the theory of algebraic\nlaminations dual to trees, as developed by Coulbois, Hilion, Lustig and\nReynolds, to the context of free products; this also gives us an opportunity to\ngive a unified account of this theory. We first show that any $\\mathbb{R}$-tree\nwith dense orbits in the boundary of the corresponding outer space can be\nreconstructed as a quotient of the boundary of the group by its dual\nlamination. We then describe the dual lamination in terms of a band complex on\ncompact $\\mathbb{R}$-trees (generalizing Coulbois-Hilion-Lustig's compact\nheart), and we analyze this band complex using versions of the Rips machine and\nof the Rauzy-Veech induction. An important output of the theory is that the\nabove map from the boundary of the group to the $\\mathbb{R}$-tree is 2-to-1\nalmost everywhere.\nA key point for our intended application is a unique duality result for\narational trees. It says that if two trees have a leaf in common in their dual\nlaminations, and if one of the trees is arational and relatively free, then\nthey are equivariantly homeomorphic.\nThis statement is an analogue of a result in the free group saying that if\ntwo trees are dual to a common current and one of the trees is free arational,\nthen the two trees are equivariantly homeomorphic. However, we notice that in\nthe setting of free products, the continuity of the pairing between trees and\ncurrents fails. For this reason, in all this paper, we work with laminations\nrather than with currents.\n",
"title": "Algebraic laminations for free products and arational trees"
}
| null | null | null | null | true | null |
9501
| null |
Default
| null | null |
null |
{
"abstract": " We present the transient source detection efficiencies of the Palomar\nTransient Factory (PTF), parameterizing the number of transients that PTF\nfound, versus the number of similar transients that occurred over the same\nperiod in the survey search area but that were missed. PTF was an optical sky\nsurvey carried out with the Palomar 48-inch telescope over 2009-2012, observing\nmore than 8000 square degrees of sky with cadences of between 1 and 5 days,\nlocating around 50,000 non-moving transient sources, and spectroscopically\nconfirming around 1900 supernovae. We assess the effectiveness with which PTF\ndetected transient sources, by inserting ~7 million artificial point sources\ninto real PTF data. We then study the efficiency with which the PTF real-time\npipeline recovered these sources as a function of the source magnitude, host\ngalaxy surface brightness, and various observing conditions (using proxies for\nseeing, sky brightness, and transparency). The product of this study is a\nmulti-dimensional recovery efficiency grid appropriate for the range of\nobserving conditions that PTF experienced, and that can then be used for\nstudies of the rates, environments, and luminosity functions of different\ntransient types using detailed Monte Carlo simulations. We illustrate the\ntechnique using the observationally well-understood class of type Ia\nsupernovae.\n",
"title": "Real-Time Recovery Efficiencies and Performance of the Palomar Transient Factory's Transient Discovery Pipeline"
}
| null | null |
[
"Physics"
] | null | true | null |
9502
| null |
Validated
| null | null |
null |
{
"abstract": " In this paper, we consider isotropic and stationary max-stable, inverse\nmax-stable and max-mixture processes $X=(X(s))\\_{s\\in\\bR^2}$ and the damage\nfunction $\\cD\\_X^{\\nu}= |X|^\\nu$ with $0<\\nu<1/2$. We study the quantitative\nbehavior of a risk measure which is the variance of the average of\n$\\cD\\_X^{\\nu}$ over a region $\\mathcal{A}\\subset \\bR^2$.} This kind of risk\nmeasure has already been introduced and studied for \\vero{some} max-stable\nprocesses in \\cite{koch2015spatial}. %\\textcolor{red}{In this study, we\ngeneralised this risk measure to be applicable for several models: asymptotic\ndependence represented by max-stable, asymptotic independence represented by\ninverse max-stable and mixing between of them.} We evaluated the proposed risk\nmeasure by a simulation study.\n",
"title": "Spatial Risk Measure for Max-Stable and Max-Mixture Processes"
}
| null | null | null | null | true | null |
9503
| null |
Default
| null | null |
null |
{
"abstract": " Given a direct system of Hilbert spaces $s\\mapsto \\mathcal H_s$ (with\nisometric inclusion maps $\\iota_s^t:\\mathcal H_s\\rightarrow \\mathcal H_t$ for\n$s\\leq t$) corresponding to quantum systems on scales $s$, we define notions of\nscale invariant and weakly scale invariant operators. Is some cases of quantum\nspin chains we find conditions for transfer matrices and nearest neighbour\nHamiltonians to be scale invariant or weakly so. Scale invariance forces\nspatial inhomogeneity of the spectral parameter. But weakly scale invariant\ntransfer matrices may be spatially homogeneous in which case the change of\nspectral parameter from one scale to another is governed by a classical\ndynamical system exhibiting fractal behaviour.\n",
"title": "Scale invariant transfer matrices and Hamiltionians"
}
| null | null |
[
"Mathematics"
] | null | true | null |
9504
| null |
Validated
| null | null |
null |
{
"abstract": " With a plethora of available classification performance measures, choosing\nthe right metric for the right task requires careful thought. To make this\ndecision in an informed manner, one should study and compare general properties\nof candidate measures. However, analysing measures with respect to complete\nranges of their domain values is a difficult and challenging task. In this\nstudy, we attempt to support such analyses with a specialized visualization\ntechnique, which operates in a barycentric coordinate system using a 3D\ntetrahedron. Additionally, we adapt this technique to the context of imbalanced\ndata and put forward a set of properties which should be taken into account\nwhen selecting a classification performance measure. As a result, we compare 22\npopular measures and show important differences in their behaviour. Moreover,\nfor parametric measures such as the F$_{\\beta}$ and IBA$_\\alpha$(G-mean), we\nanalytically derive parameter thresholds that change measure properties.\nFinally, we provide an online visualization tool that can aid the analysis of\ncomplete domain ranges of performance measures.\n",
"title": "Visual-Based Analysis of Classification Measures with Applications to Imbalanced Data"
}
| null | null | null | null | true | null |
9505
| null |
Default
| null | null |
null |
{
"abstract": " Modern large displacement optical flow algorithms usually use an\ninitialization by either sparse descriptor matching techniques or dense\napproximate nearest neighbor fields. While the latter have the advantage of\nbeing dense, they have the major disadvantage of being very outlier-prone as\nthey are not designed to find the optical flow, but the visually most similar\ncorrespondence. In this article we present a dense correspondence field\napproach that is much less outlier-prone and thus much better suited for\noptical flow estimation than approximate nearest neighbor fields. Our approach\ndoes not require explicit regularization, smoothing (like median filtering) or\na new data term. Instead we solely rely on patch matching techniques and a\nnovel multi-scale matching strategy. We also present enhancements for outlier\nfiltering. We show that our approach is better suited for large displacement\noptical flow estimation than modern descriptor matching techniques. We do so by\ninitializing EpicFlow with our approach instead of their originally used\nstate-of-the-art descriptor matching technique. We significantly outperform the\noriginal EpicFlow on MPI-Sintel, KITTI 2012, KITTI 2015 and Middlebury. In this\nextended article of our former conference publication we further improve our\napproach in matching accuracy as well as runtime and present more experiments\nand insights.\n",
"title": "Flow Fields: Dense Correspondence Fields for Highly Accurate Large Displacement Optical Flow Estimation"
}
| null | null | null | null | true | null |
9506
| null |
Default
| null | null |
null |
{
"abstract": " We grew Lix(NH3)yFe2Te1.2Se0.8 single crystals successfully using the\nlow-temperature ammonothermal method and the onset superconducting transition\ntemperature Tc,onset is increased to 21 K when compared to 14 K in the parent\ncompound FeTe0.6Se0.4. The derived critical current density Jc increases\nremarkably to 2.6*10^5 A/cm^2 at 2 K. Further analysis indicates that the\ndominant pinning mechanism in Lix(NH3)yFe2Te1.2Se0.8 single crystal is the\ninteraction between vortex and surface-like defects with normal core, possibly\noriginating from the stacking faults along the c axis, by variations in the\ncharge-carrier mean free path l near the defects (delta l pinning). Moreover,\nthe flux creep is important to the vortex dynamics of this material.\n",
"title": "Critical current density and vortex pinning mechanism of Lix(NH3)yFe2Te1.2Se0.8 single crystals"
}
| null | null | null | null | true | null |
9507
| null |
Default
| null | null |
null |
{
"abstract": " Electron-electron correlation forms the basis of difficulties encountered in\nmany-body problems. Accurate treatment of the correlation problem is likely to\nunravel some nice physical properties of matter embedded in this correlation.\nIn an effort to tackle this many-body problem, two complementary parameter-free\npseudopotentials for $n$-electron atoms and ions are suggested in this study.\nUsing one of the pseudopotentials, near-exact values of the groundstate\nionization potentials of helium, lithium, and berrylium atoms have been\ncalculated. The other pseudopotential also proves to be capable of yielding\nreasonable and reliable quantum physical observables within the\nnon-relativistic quantum mechanics.\n",
"title": "Pseudopotential for Many-Electron Atoms and Ions"
}
| null | null | null | null | true | null |
9508
| null |
Default
| null | null |
null |
{
"abstract": " We present a semi-analytical correction to the seminal solution for the\nsecular motion of a planet's orbit under gravitational influence of an external\nperturber derived by Heppenheimer (1978). A comparison between analytical\npredictions and numerical simulations allows us to determine corrective factors\nfor the secular frequency and forced eccentricity in the co-planar restricted\nthree-body problem. The correction is given in the form of a polynomial\nfunction of the system's parameters that can be applied to first-order forced\neccentricity and secular frequency estimates. The resulting secular equations\nare simple, straight forward to use and improve the fidelity of Heppenheimer's\nsolution well beyond higher-order models. The quality and convergence of the\ncorrected secular equations are tested for a wide range of parameters and\nlimits of its applicability are given.\n",
"title": "Secular Orbit Evolution in Systems with a Strong External Perturber - A Simple and Accurate Model"
}
| null | null | null | null | true | null |
9509
| null |
Default
| null | null |
null |
{
"abstract": " Making an informed, correct and quick decision can be life-saving. It's\ncrucial for animals during an escape behaviour or for autonomous cars during\ndriving. The decision can be complex and may involve an assessment of the\namount of threats present and the nature of each threat. Thus, we should expect\nearly sensory processing to supply classification information fast and\naccurately, even before relying the information to higher brain areas or more\ncomplex system components downstream. Today, advanced convolutional artificial\nneural networks can successfully solve visual detection and classification\ntasks and are commonly used to build complex decision making systems. However,\nin order to perform well on these tasks they require increasingly complex,\n\"very deep\" model structure, which is costly in inference run-time, energy\nconsumption and number of training samples, only trainable on cloud-computing\nclusters. A single spiking neuron has been shown to be able to solve\nrecognition tasks for homogeneous Poisson input statistics, a commonly used\nmodel for spiking activity in the neocortex. When modeled as leaky integrate\nand fire with gradient decent learning algorithm it was shown to posses a\nvariety of complex computational capabilities. Here we improve its\nimplementation. We also account for more natural stimulus generated inputs that\ndeviate from this homogeneous Poisson spiking. The improved gradient-based\nlocal learning rule allows for significantly better and stable generalization.\nWe also show that with its improved capabilities it can count weakly labeled\nconcepts by applying our model to a problem of multiple instance learning (MIL)\nwith counting where labels are only available for collections of concepts. In\nthis counting MNIST task the neuron exploits the improved implementation and\noutperforms conventional ConvNet architecture under similar condtions.\n",
"title": "Reliable counting of weakly labeled concepts by a single spiking neuron model"
}
| null | null | null | null | true | null |
9510
| null |
Default
| null | null |
null |
{
"abstract": " This paper investigates the stability of distance-based \\textit{flexible}\nundirected formations in the plane. Without rigidity, there exists a set of\nconnected shapes for given distance constraints, which is called the ambit. We\nshow that a flexible formation can lose its flexibility, or equivalently may\nreduce the degrees of freedom of its ambit, if a small disturbance is\nintroduced in the range sensor of the agents. The stability of the disturbed\nequilibrium can be characterized by analyzing the eigenvalues of the linearized\naugmented error system. Unlike infinitesimally rigid formations, the disturbed\ndesired equilibrium can be turned unstable regardless of how small the\ndisturbance is. We finally present two examples of how to exploit these\ndisturbances as design parameters. The first example shows how to combine rigid\nand flexible formations such that some of the agents can move freely in the\ndesired and locally stable ambit. The second example shows how to achieve a\nspecific shape with fewer edges than the necessary for the standard controller\nin rigid formations.\n",
"title": "On the stability and applications of distance-based flexible formations"
}
| null | null |
[
"Computer Science"
] | null | true | null |
9511
| null |
Validated
| null | null |
null |
{
"abstract": " The general space-time evolution of the scattering of an incident acoustic\nplane wave pulse by an arbitrary configuration of targets is treated by\nemploying a recently developed non-singular boundary integral method to solve\nthe Helmholtz equation in the frequency domain from which the fast Fourier\ntransform is used to obtain the full space-time solution of the wave equation.\nThe non-singular boundary integral solution can enforce the radiation boundary\ncondition at infinity exactly and can account for multiple scattering effects\nat all spacings between scatterers without adverse effects on the numerical\nprecision. More generally, the absence of singular kernels in the non-singular\nintegral equation confers high numerical stability and precision for smaller\nnumbers of degrees of freedom. The use of fast Fourier transform to obtain the\ntime dependence is not constrained to discrete time steps and is particularly\nefficient for studying the response to different incident pulses by the same\nconfiguration of scatterers. The precision that can be attained using a smaller\nnumber of Fourier components is also quantified.\n",
"title": "Space-time domain solutions of the wave equation by a non-singular boundary integral method and Fourier transform"
}
| null | null |
[
"Physics"
] | null | true | null |
9512
| null |
Validated
| null | null |
null |
{
"abstract": " For subspace estimation with an unknown colored noise, Factor Analysis (FA)\nis a good candidate for replacing the popular eigenvalue decomposition (EVD).\nFinding the unknowns in factor analysis can be done by solving a non-linear\nleast square problem. For this type of optimization problems, the Gauss-Newton\n(GN) algorithm is a powerful and simple method. The most expensive part of the\nGN algorithm is finding the direction of descent by solving a system of\nequations at each iteration. In this paper we show that for FA, the matrices\ninvolved in solving these systems of equations can be diagonalized in a closed\nform fashion and the solution can be found in a computationally efficient way.\nWe show how the unknown parameters can be updated without actually constructing\nthese matrices. The convergence performance of the algorithm is studied via\nnumerical simulations.\n",
"title": "Constrained Least Squares for Extended Complex Factor Analysis"
}
| null | null | null | null | true | null |
9513
| null |
Default
| null | null |
null |
{
"abstract": " The resilience of a complex interconnected system concerns the size of the\nmacroscopic functioning node clusters after external perturbations based on a\nrandom or designed scheme. For a representation of the interconnected systems\nwith directional or asymmetrical interactions among constituents, the directed\nnetwork is a convenient choice. Yet how the interaction directions affect the\nnetwork resilience still lacks thorough exploration. Here, we study the\nresilience of directed networks with a generalized $k$-core pruning process as\na simple failure procedure based on both the in- and out-degrees of nodes, in\nwhich any node with an in-degree $< k_{in}$ or an out-degree $< k_{ou}$ is\nremoved iteratively. With an explicitly analytical framework, we can predict\nthe relative sizes of residual node clusters on uncorrelated directed random\ngraphs. We show that the discontinuous transitions rise for cases with $k_{in}\n\\geq 2$ or $k_{ou} \\geq 2$, and the unidirectional interactions among nodes\ndrive the networks more vulnerable against perturbations based on in- and\nout-degrees separately.\n",
"title": "Generalized $k$-core pruning process on directed networks"
}
| null | null | null | null | true | null |
9514
| null |
Default
| null | null |
null |
{
"abstract": " This paper presents several test cases intended to be benchmarks for\nnumerical schemes for single-phase fluid flow in fractured porous media. A\nnumber of solution strategies are compared, including a vertex and a\ncell-centered finite volume method, a non-conforming embedded discrete fracture\nmodel, a primal and a dual extended finite element formulation, and a mortar\ndiscrete fracture model. The proposed benchmarks test the schemes by increasing\nthe difficulties in terms of network geometry, e.g. intersecting fractures, and\nphysical parameters, e.g. low and high fracture-matrix permeability ratio as\nwell as heterogeneous fracture permeabilities. For each problem, the results\npresented by the participants are the number of unknowns, the approximation\nerrors in the porous matrix and in the fractures with respect to a reference\nsolution, and the sparsity and condition number of the discretized linear\nsystem. All data and meshes used in this study are publicly available for\nfurther comparisons.\n",
"title": "Benchmarks for single-phase flow in fractured porous media"
}
| null | null |
[
"Computer Science",
"Mathematics"
] | null | true | null |
9515
| null |
Validated
| null | null |
null |
{
"abstract": " Authorship attribution is a natural language processing task that has been\nwidely studied, often by considering small order statistics. In this paper, we\nexplore a complex network approach to assign the authorship of texts based on\ntheir mesoscopic representation, in an attempt to capture the flow of the\nnarrative. Indeed, as reported in this work, such an approach allowed the\nidentification of the dominant narrative structure of the studied authors. This\nhas been achieved due to the ability of the mesoscopic approach to take into\naccount relationships between different, not necessarily adjacent, parts of the\ntext, which is able to capture the story flow. The potential of the proposed\napproach has been illustrated through principal component analysis, a\ncomparison with the chance baseline method, and network visualization. Such\nvisualizations reveal individual characteristics of the authors, which can be\nunderstood as a kind of calligraphy.\n",
"title": "On the \"Calligraphy\" of Books"
}
| null | null | null | null | true | null |
9516
| null |
Default
| null | null |
null |
{
"abstract": " Building a voice conversion (VC) system from non-parallel speech corpora is\nchallenging but highly valuable in real application scenarios. In most\nsituations, the source and the target speakers do not repeat the same texts or\nthey may even speak different languages. In this case, one possible, although\nindirect, solution is to build a generative model for speech. Generative models\nfocus on explaining the observations with latent variables instead of learning\na pairwise transformation function, thereby bypassing the requirement of speech\nframe alignment. In this paper, we propose a non-parallel VC framework with a\nvariational autoencoding Wasserstein generative adversarial network (VAW-GAN)\nthat explicitly considers a VC objective when building the speech model.\nExperimental results corroborate the capability of our framework for building a\nVC system from unaligned data, and demonstrate improved conversion quality.\n",
"title": "Voice Conversion from Unaligned Corpora using Variational Autoencoding Wasserstein Generative Adversarial Networks"
}
| null | null |
[
"Computer Science"
] | null | true | null |
9517
| null |
Validated
| null | null |
null |
{
"abstract": " Numerous institutions and organizations need not only to preserve the\nmaterial and publications they produce, but also have as their task (although\nit would be desirable it was an obligation) to publish, disseminate and make\npublicly available all the results of the research and any other\nscientific/academic material. The Open Archives Initiative (OAI) and the\nintroduction of Open Archives Initiative Protocol for Metadata Harvesting\n(OAI-PMH), make this task much easier. The main objective of this work is to\nmake a comparative and qualitative study of the data -metadata specifically-\ncontained in the whole set of Argentine repositories listed in the ROAR portal,\nfocusing on the functional perspective of the quality of this metadata. Another\nobjective is to offer an overview of the status of these repositories, in an\nattempt to detect common failures and errors institutions incur when storing\nthe metadata of the resources contained in these repositories, and thus be able\nto suggest measures to be able to improve the load and further retrieval\nprocesses. It was found that the eight most used Dublin Core fields are:\nidentifier, type, title, date, subject, creator, language and description. Not\nall repositories fill all the fields, and the lack of normalization, or the\nexcessive use of fields like language, type, format and subject is somewhat\nstriking, and in some cases even alarming\n",
"title": "Calidad en repositorios digitales en Argentina, estudio comparativo y cualitativo"
}
| null | null | null | null | true | null |
9518
| null |
Default
| null | null |
null |
{
"abstract": " Time-triggered and event-triggered control strategies for stabilization of an\nunstable plant over a rate-limited communication channel subject to unknown,\nbounded delay are studied and compared. Event triggering carries implicit\ninformation, revealing the state of the plant. However, the delay in the\ncommunication channel causes information loss, as it makes the state\ninformation out of date. There is a critical delay value, when the loss of\ninformation due to the communication delay perfectly compensates the implicit\ninformation carried by the triggering events. This occurs when the maximum\ndelay equals the inverse of the entropy rate of the plant. In this context,\nextensions of our previous results for event triggering strategies are\npresented for vector systems and are compared with the data-rate theorem for\ntime-triggered control, that is extended here to a setting with unknown delay.\n",
"title": "Time-triggering versus event-triggering control over communication channels"
}
| null | null | null | null | true | null |
9519
| null |
Default
| null | null |
null |
{
"abstract": " We study Lipschitz, positively homogeneous and finite suprema preserving\nmappings defined on a max-cone of positive elements in a normed vector lattice.\nWe prove that the lower spectral radius of such a mapping is always a minimum\nvalue of its approximate point spectrum. We apply this result to show that the\nspectral mapping theorem holds for the approximate point spectrum of such a\nmapping. By applying this spectral mapping theorem we obtain new inequalites\nfor the Bonsall cone spectral radius of max type kernel operators.\n",
"title": "Lower spectral radius and spectral mapping theorem for suprema preserving mappings"
}
| null | null |
[
"Mathematics"
] | null | true | null |
9520
| null |
Validated
| null | null |
null |
{
"abstract": " In online social networks people often express attitudes towards others,\nwhich forms massive sentiment links among users. Predicting the sign of\nsentiment links is a fundamental task in many areas such as personal\nadvertising and public opinion analysis. Previous works mainly focus on textual\nsentiment classification, however, text information can only disclose the \"tip\nof the iceberg\" about users' true opinions, of which the most are unobserved\nbut implied by other sources of information such as social relation and users'\nprofile. To address this problem, in this paper we investigate how to predict\npossibly existing sentiment links in the presence of heterogeneous information.\nFirst, due to the lack of explicit sentiment links in mainstream social\nnetworks, we establish a labeled heterogeneous sentiment dataset which consists\nof users' sentiment relation, social relation and profile knowledge by\nentity-level sentiment extraction method. Then we propose a novel and flexible\nend-to-end Signed Heterogeneous Information Network Embedding (SHINE) framework\nto extract users' latent representations from heterogeneous networks and\npredict the sign of unobserved sentiment links. SHINE utilizes multiple deep\nautoencoders to map each user into a low-dimension feature space while\npreserving the network structure. We demonstrate the superiority of SHINE over\nstate-of-the-art baselines on link prediction and node recommendation in two\nreal-world datasets. The experimental results also prove the efficacy of SHINE\nin cold start scenario.\n",
"title": "SHINE: Signed Heterogeneous Information Network Embedding for Sentiment Link Prediction"
}
| null | null | null | null | true | null |
9521
| null |
Default
| null | null |
null |
{
"abstract": " We prove elimination of field quantifiers for strongly dependent henselian\nfields in the Denef-Pas language. This is achieved by proving the result for a\nclass of fields generalizing algebraically maximal Kaplansky fields. We deduce\nthat if $(K,v)$ is strongly dependent then so is its henselization.\n",
"title": "Eliminating Field Quantifiers in Strongly Dependent Henselian Fields"
}
| null | null | null | null | true | null |
9522
| null |
Default
| null | null |
null |
{
"abstract": " Several domains have adopted the increasing use of IoT-based devices to\ncollect sensor data for generating abstractions and perceptions of the real\nworld. This sensor data is multi-modal and heterogeneous in nature. This\nheterogeneity induces interoperability issues while developing cross-domain\napplications, thereby restricting the possibility of reusing sensor data to\ndevelop new applications. As a solution to this, semantic approaches have been\nproposed in the literature to tackle problems related to interoperability of\nsensor data. Several ontologies have been proposed to handle different aspects\nof IoT-based sensor data collection, ranging from discovering the IoT sensors\nfor data collection to applying reasoning on the collected sensor data for\ndrawing inferences. In this paper, we survey these existing semantic ontologies\nto provide an overview of the recent developments in this field. We highlight\nthe fundamental ontological concepts (e.g., sensor-capabilities and\ncontext-awareness) required for an IoT-based application, and survey the\nexisting ontologies which include these concepts. Based on our study, we also\nidentify the shortcomings of currently available ontologies, which serves as a\nstepping stone to state the need for a common unified ontology for the IoT\ndomain.\n",
"title": "A study of existing Ontologies in the IoT-domain"
}
| null | null | null | null | true | null |
9523
| null |
Default
| null | null |
null |
{
"abstract": " The demand for metals by modern technology has been shifting from common base\nmetals to a variety of minor metals, such as cobalt or indium. The industrial\nimportance and limited geological availability of some minor metals have led to\nthem being considered more \"critical,\" and there is a growing investment\ninterest in such critical metals and their producing companies. In this\nresearch, we create a novel framework, Dynamic Advisor-Based Ensemble (dynABE),\nfor stock prediction and use critical metal companies as case study. dynABE\nuses domain knowledge to diversify the feature set by dividing them into\ndifferent \"advisors.\" creates high-level ensembles with complex base models for\neach advisor, and combines the advisors together dynamically during validation\nwith a novel and effective online update strategy. We test dynABE on three\ncobalt-related companies, and it achieves the best-case misclassification error\nof 31.12% and excess return of 477% compared to the stock itself in a year and\na half. In addition to presenting an effective stock prediction model with\ndecent profitabilities, this research further analyzes dynABE to visualize how\nit works in practice, which also yields discoveries of its interesting\nbehaviors when processing time-series data.\n",
"title": "Dynamic Advisor-Based Ensemble (dynABE): Case Study in Stock Trend Prediction of Critical Metal Companies"
}
| null | null | null | null | true | null |
9524
| null |
Default
| null | null |
null |
{
"abstract": " A high speed quasi-distributed demodulation method based on the microwave\nphotonics and the chromatic dispersion effect is designed and implemented for\nweak fiber Bragg gratings (FBGs). Due to the effect of dispersion compensation\nfiber (DCF), FBG wavelength shift leads to the change of the difference\nfrequency signal at the mixer. With the way of crossing microwave sweep cycle,\nall wavelengths of cascade FBGs can be high speed obtained by measuring the\nfrequencies change. Moreover, through the introduction of Chirp-Z and Hanning\nwindow algorithm, the analysis of difference frequency signal is achieved very\nwell. By adopting the single-peak filter as a reference, the length disturbance\nof DCF caused by temperature can be also eliminated. Therefore, the accuracy of\nthis novel method is greatly improved, and high speed demodulation of FBGs can\neasily realize. The feasibility and performance are experimentally demonstrated\nusing 105 FBGs with 0.1% reflectivity, 1 m spatial interval. Results show that\neach grating can be distinguished well, and the demodulation rate is as high as\n40 kHz, the accuracy is about 8 pm.\n",
"title": "High-Speed Demodulation of weak FBGs Based on Microwave Photonics and Chromatic Dispersion"
}
| null | null | null | null | true | null |
9525
| null |
Default
| null | null |
null |
{
"abstract": " We study the loss of coherence of electrochemical oscillations on meso- and\nnanosized electrodes with numeric simulations of the electrochemical master\nequation for a prototypical electrochemical oscillator, the hydrogen peroxide\nreduction on Pt electrodes in the presence of halides. On nanoelectrodes, the\nelectrode potential changes whenever a stochastic electron-transfer event takes\nplace. Electrochemical reaction rate coefficients depend exponentially on the\nelectrode potential and become thus fluctuating quantities as well. Therefore,\nalso the transition rates between system states become time-dependent which\nconstitutes a fundamental difference to purely chemical nanoscale oscillators.\nThree implications are demonstrated: (a) oscillations and steady states shift\nin phase space with decreasing system size, thereby also decreasing\nconsiderably the oscillating parameter regions; (b) the minimal number of\nmolecules necessary to support correlated oscillations is more than 10 times as\nlarge as for nanoscale chemical oscillators; (c) the relation between\ncorrelation time and variance of the period of the oscillations predicted for\nchemical oscillators in the weak noise limit is only fulfilled in a very\nrestricted parameter range for the electrochemical nano-oscillator.\n",
"title": "Destructive Impact of Molecular Noise on Nanoscale Electrochemical Oscillators"
}
| null | null | null | null | true | null |
9526
| null |
Default
| null | null |
null |
{
"abstract": " We present a new algorithm for constructive recognition of the Suzuki groups\nin their natural representations. The algorithm runs in Las Vegas polynomial\ntime given a discrete logarithm oracle. An implementation is available in the\nMagma computer algebra system.\n",
"title": "A new method for recognising Suzuki groups"
}
| null | null |
[
"Computer Science",
"Mathematics"
] | null | true | null |
9527
| null |
Validated
| null | null |
null |
{
"abstract": " We display the entire structure ${\\cal R}_2$ coding $\\Sigma_1$- and\n$\\Sigma_2$-elementarity on the ordinals. This leads to the first steps for\nanalyzing pure $\\Sigma_3$-elementary substructures.\n",
"title": "Pure $Σ_2$-Elementarity beyond the Core"
}
| null | null | null | null | true | null |
9528
| null |
Default
| null | null |
null |
{
"abstract": " A new, radical CNN design approach is presented in this paper, considering\nthe reduction of the total computational load during inference. This is\nachieved by a new holistic intervention on both the CNN architecture and the\ntraining procedure, which targets to the parsimonious inference by learning to\nexploit or remove the redundant capacity of a CNN architecture. This is\naccomplished, by the introduction of a new structural element that can be\ninserted as an add-on to any contemporary CNN architecture, whilst preserving\nor even improving its recognition accuracy. Our approach formulates a\nsystematic and data-driven method for developing CNNs that are trained to\neventually change size and form in real-time during inference, targeting to the\nsmaller possible computational footprint. Results are provided for the optimal\nimplementation on a few modern, high-end mobile computing platforms indicating\na significant speed-up of up to x3 times.\n",
"title": "Parsimonious Inference on Convolutional Neural Networks: Learning and applying on-line kernel activation rules"
}
| null | null | null | null | true | null |
9529
| null |
Default
| null | null |
null |
{
"abstract": " Journals were central to Eugene Garfield's research interests. Among other\nthings, journals are considered as units of analysis for bibliographic\ndatabases such as the Web of Science (WoS) and Scopus. In addition to\ndisciplinary classifications of journals, journal citation patterns span\nnetworks across boundaries to variable extents. Using betweenness centrality\n(BC) and diversity, we elaborate on the question of how to distinguish and rank\njournals in terms of interdisciplinarity. Interdisciplinarity, however, is\ndifficult to operationalize in the absence of an operational definition of\ndisciplines, the diversity of a unit of analysis is sample-dependent. BC can be\nconsidered as a measure of multi-disciplinarity. Diversity of co-citation in a\nciting document has been considered as an indicator of knowledge integration,\nbut an author can also generate trans-disciplinary--that is,\nnon-disciplined--variation by citing sources from other disciplines. Diversity\nin the bibliographic coupling among citing documents can analogously be\nconsidered as diffusion of knowledge across disciplines. Because the citation\nnetworks in the cited direction reflect both structure and variation, diversity\nin this direction is perhaps the best available measure of interdisciplinarity\nat the journal level. Furthermore, diversity is based on a summation and can\ntherefore be decomposed, differences among (sub)sets can be tested for\nstatistical significance. In an appendix, a general-purpose routine for\nmeasuring diversity in networks is provided.\n",
"title": "Betweenness and Diversity in Journal Citation Networks as Measures of Interdisciplinarity -- A Tribute to Eugene Garfield --"
}
| null | null |
[
"Computer Science"
] | null | true | null |
9530
| null |
Validated
| null | null |
null |
{
"abstract": " Partially observable environments present an important open challenge in the\ndomain of sequential control learning with delayed rewards. Despite numerous\nattempts during the two last decades, the majority of reinforcement learning\nalgorithms and associated approximate models, applied to this context, still\nassume Markovian state transitions. In this paper, we explore the use of a\nrecently proposed attention-based model, the Gated End-to-End Memory Network,\nfor sequential control. We call the resulting model the Gated End-to-End Memory\nPolicy Network. More precisely, we use a model-free value-based algorithm to\nlearn policies for partially observed domains using this memory-enhanced neural\nnetwork. This model is end-to-end learnable and it features unbounded memory.\nIndeed, because of its attention mechanism and associated non-parametric\nmemory, the proposed model allows us to define an attention mechanism over the\nobservation stream unlike recurrent models. We show encouraging results that\nillustrate the capability of our attention-based model in the context of the\ncontinuous-state non-stationary control problem of stock trading. We also\npresent an OpenAI Gym environment for simulated stock exchange and explain its\nrelevance as a benchmark for the field of non-Markovian decision process\nlearning.\n",
"title": "Non-Markovian Control with Gated End-to-End Memory Policy Networks"
}
| null | null | null | null | true | null |
9531
| null |
Default
| null | null |
null |
{
"abstract": " Context. We are creating the AKARI mid-infrared all-sky diffuse maps. Through\na foreground removal of the zodiacal emission, we serendipitously detected a\nbright residual component whose angular size is about 50 x 20 deg. at a\nwavelength of 9 micron. Aims. We investigate the origin and the physical\nproperties of the residual component. Methods. We measured the surface\nbrightness of the residual component in the AKARI mid-infrared all-sky maps.\nResults. The residual component was significantly detected only in 2007\nJanuary, even though the same region was observed in 2006 July and 2007 July,\nwhich shows that it is not due to the Galactic emission. We suggest that this\nmay be a small cloud passing near the Earth. By comparing the observed\nintensity ratio of I_9um/I_18um with the expected intensity ratio assuming\nthermal equilibrium of dust grains at 1 AU for various dust compositions and\nsizes, we find that dust grains in the moving cloud are likely to be much\nsmaller than typical grains that produce the bulk of the zodiacal light.\nConclusions. Considering the observed date and position, it is likely that it\noriginates in the solar coronal mass ejection (CME) which took place on 2007\nJanuary 25.\n",
"title": "A likely detection of a local interplanetary dust cloud passing near the Earth in the AKARI mid-infrared all-sky map"
}
| null | null |
[
"Physics"
] | null | true | null |
9532
| null |
Validated
| null | null |
null |
{
"abstract": " Convective mixing in Helium-core-burning (HeCB) stars is one of the\noutstanding issues in stellar modelling. The precise asteroseismic measurements\nof gravity-modes period spacing ($\\Delta\\Pi_1$) has opened the door to detailed\nstudies of the near-core structure of such stars, which had not been possible\nbefore. Here we provide stringent tests of various core-mixing scenarios\nagainst the largely unbiased population of red-clump stars belonging to the old\nopen clusters monitored by Kepler, and by coupling the updated precise\ninference on $\\Delta\\Pi_1$ in thousands field stars with spectroscopic\nconstraints. We find that models with moderate overshooting successfully\nreproduce the range observed of $\\Delta\\Pi_1$ in clusters. In particular we\nshow that there is no evidence for the need to extend the size of the\nadiabatically stratified core, at least at the beginning of the HeCB phase.\nThis conclusion is based primarily on ensemble studies of $\\Delta\\Pi_1$ as a\nfunction of mass and metallicity. While $\\Delta\\Pi_1$ shows no appreciable\ndependence on the mass, we have found a clear dependence of $\\Delta\\Pi_1$ on\nmetallicity, which is also supported by predictions from models.\n",
"title": "Kepler red-clump stars in the field and in open clusters: constraints on core mixing"
}
| null | null | null | null | true | null |
9533
| null |
Default
| null | null |
null |
{
"abstract": " Neurons and networks in the cerebral cortex must operate reliably despite\nmultiple sources of noise. To evaluate the impact of both input and output\nnoise, we determine the robustness of single-neuron stimulus selective\nresponses, as well as the robustness of attractor states of networks of neurons\nperforming memory tasks. We find that robustness to output noise requires\nsynaptic connections to be in a balanced regime in which excitation and\ninhibition are strong and largely cancel each other. We evaluate the conditions\nrequired for this regime to exist and determine the properties of networks\noperating within it. A plausible synaptic plasticity rule for learning that\nbalances weight configurations is presented. Our theory predicts an optimal\nratio of the number of excitatory and inhibitory synapses for maximizing the\nencoding capacity of balanced networks for a given statistics of afferent\nactivations. Previous work has shown that balanced networks amplify\nspatio-temporal variability and account for observed asynchronous irregular\nstates. Here we present a novel type of balanced network that amplifies small\nchanges in the impinging signals, and emerges automatically from learning to\nperform neuronal and network functions robustly.\n",
"title": "Balanced Excitation and Inhibition are Required for High-Capacity, Noise-Robust Neuronal Selectivity"
}
| null | null |
[
"Computer Science",
"Physics",
"Statistics"
] | null | true | null |
9534
| null |
Validated
| null | null |
null |
{
"abstract": " Extended Air Showers produced by cosmic rays impinging on the earth\natmosphere irradiate radio frequency radiation through different mechanisms.\nUpon certain conditions, the emission has a coherent nature, with the\nconsequence that the emitted power is not proportional to the energy of the\nprimary cosmic rays, but to the energy squared. The effect was predicted in\n1962 by Askaryan and it is nowadays experimentally well established and\nexploited for the detection of ultra high energy cosmic rays.\nIn this paper we discuss in details the conditions for coherence, which in\nliterature have been too often taken for granted, and calculate them\nanalytically, finding a formulation which comprehends both the coherent and the\nincoherent emissions. We apply the result to the Cherenkov effect, obtaining\nthe same conclusions derived by Askaryan, and to the geosynchrotron radiation.\n",
"title": "On the coherent emission of radio frequency radiation from high energy particle showers"
}
| null | null | null | null | true | null |
9535
| null |
Default
| null | null |
null |
{
"abstract": " It is argued that the concept of \"technical tie\" in electoral polls and quick\ncounts has no probabilistic basis, and that instead the uncertainty associated\nwith these statistical exercises should be expressed in terms of a probability\nof victory of the leading candidate.\n-----\nSe argumenta que el concepto de \"empate técnico\" en encuestas y conteos\nrápidos electorales no tiene fundamento probabilístico, y que en su lugar\nla incertidumbre asociada a dichos ejercicios estadísticos debiera expresarse\nen términos de una probabilidad de triunfo del candidato puntero.\n",
"title": "La falacia del empate técnico electoral"
}
| null | null |
[
"Statistics"
] | null | true | null |
9536
| null |
Validated
| null | null |
null |
{
"abstract": " Recent discovery of pyrite FeO$_2$, which can be an important ingredient of\nthe Earth's lower mantle and which in particular may serve as an extra source\nof water in the Earth's interior, opens new perspectives for geophysics and\ngeochemistry, but this is also an extremely interesting material from physical\npoint of view. We found that in contrast to naive expectations Fe is nearly 3+\nin this material, which strongly affects its magnetic properties and makes it\nqualitatively different from well known sulfide analogue - FeS$_2$. Doping,\nwhich is most likely to occur in the Earth's mantle, makes FeO$_2$ much more\nmagnetic. In addition we show that unique electronic structure places FeO$_2$\n\"in between\" the usual dioxides and peroxides making this system interesting\nboth for physics and solid state chemistry.\n",
"title": "Unexpected 3+ valence of iron in FeO$_2$, a geologically important material lying \"in between\" oxides and peroxides"
}
| null | null | null | null | true | null |
9537
| null |
Default
| null | null |
null |
{
"abstract": " Despite the recent progress in automatic theorem provers, proof engineers are\nstill suffering from the lack of powerful proof automation. In this position\npaper we first report our proof strategy language based on a meta-tool\napproach. Then, we propose an AI-based approach to drastically improve proof\nautomation for Isabelle, while identifying three major challenges we plan to\naddress for this objective.\n",
"title": "Towards Smart Proof Search for Isabelle"
}
| null | null | null | null | true | null |
9538
| null |
Default
| null | null |
null |
{
"abstract": " We study the active learning problem of top-$k$ ranking from multi-wise\ncomparisons under the popular multinomial logit model. Our goal is to identify\nthe top-$k$ items with high probability by adaptively querying sets for\ncomparisons and observing the noisy output of the most preferred item from each\ncomparison. To achieve this goal, we design a new active ranking algorithm\nwithout using any information about the underlying items' preference scores. We\nalso establish a matching lower bound on the sample complexity even when the\nset of preference scores is given to the algorithm. These two results together\nshow that the proposed algorithm is nearly instance optimal (similar to\ninstance optimal [FLN03], but up to polylog factors). Our work extends the\nexisting literature on rank aggregation in three directions. First, instead of\nstudying a static problem with fixed data, we investigate the top-$k$ ranking\nproblem in an active learning setting. Second, we show our algorithm is nearly\ninstance optimal, which is a much stronger theoretical guarantee. Finally, we\nextend the pairwise comparison to the multi-wise comparison, which has not been\nfully explored in ranking literature.\n",
"title": "A Nearly Instance Optimal Algorithm for Top-k Ranking under the Multinomial Logit Model"
}
| null | null | null | null | true | null |
9539
| null |
Default
| null | null |
null |
{
"abstract": " The first concise formulation of the inverse problem on conservation laws is\npresented. In this problem one aims to derive the general form of systems of\ndifferential equations that admit a prescribed set of conservation laws. The\nparticular cases of the inverse problem on first integrals of ordinary\ndifferential equations and on conservation laws for evolution equations are\nconsidered. We also solve the inverse problem on conservation laws for\ndifferential equations admitting an infinite dimensional space of zero-order\ncharacteristics. This particular case is further studied in the context of\nconservative parameterization schemes for the two-dimensional incompressible\nEuler equations. We exhaustively classify conservative parameterization schemes\nfor the eddy-vorticity flux that lead to a class of closed, averaged Euler\nequations possessing generalized circulation, generalized momentum and energy\nconservation.\n",
"title": "Inverse problem on conservation laws"
}
| null | null | null | null | true | null |
9540
| null |
Default
| null | null |
null |
{
"abstract": " We consider an exclusion process with long jumps in the box $\\Lambda\\_N=\\{1,\n\\ldots,N-1\\}$, for $N \\ge 2$, in contact with infinitely extended reservoirs on\nits left and on its right. The jump rate is described by a transition\nprobability $p(\\cdot)$ which is symmetric, with infinite support but with\nfinite variance. The reservoirs add or remove particles with rate proportional\nto $\\kappa N^{-\\theta}$, where $\\kappa>0$ and $\\theta \\in\\mathbb R$. If\n$\\theta>0$ (resp. $\\theta<0$) the reservoirs add and fastly remove (resp.\nslowly remove) particles in the bulk. According to the value of $\\theta$ we\nprove that the time evolution of the spatial density of particles is described\nby some reaction-diffusion equations with various boundary conditions.\n",
"title": "Slow to fast infinitely extended reservoirs for the symmetric exclusion process with long jumps"
}
| null | null | null | null | true | null |
9541
| null |
Default
| null | null |
null |
{
"abstract": " In this paper we introduce a new property of two-dimensional integrable\nsystems -- existence of infinitely many local three-dimensional conservation\nlaws for pairs of integrable two-dimensional commuting flows. Infinitely many\nthree-dimensional local conservation laws for the Korteweg de Vries pair of\ncommuting flows and for the Benney commuting hydrodynamic chains are\nconstructed. As a by-product we established a new method for computation of\nlocal conservation laws for three-dimensional integrable systems. The Mikhalev\nequation and the dispersionless limit of the Kadomtsev--Petviashvili equation\nare investigated. All known local and infinitely many new quasi-local\nthree-dimensional conservation laws are presented. Also four-dimensional\nconservation laws are considered for couples of three-dimensional integrable\nquasilinear systems and for triples of corresponding hydrodynamic chains.\n",
"title": "Multi-Dimensional Conservation Laws and Integrable Systems"
}
| null | null | null | null | true | null |
9542
| null |
Default
| null | null |
null |
{
"abstract": " Are the initial conditions for clustered star formation the same as for\nnon-clustered star formation? To investigate the initial gas properties in\nyoung proto-clusters we carried out a comprehensive and high-sensitivity study\nof the internal structure, density, temperature, and kinematics of the dense\ngas content of the NGC1333 region in Perseus, one of the nearest and best\nstudied embedded clusters. The analysis of the gas velocities in the\nPosition-Position-Velocity space reveals an intricate underlying gas\norganization both in space and velocity. We identified a total of 14\nvelocity-coherent, (tran-)sonic structures within NGC1333, with similar\nphysical and kinematic properties than those quiescent, star-forming (aka\nfertile) fibers previously identified in low-mass star-forming clouds. These\nfibers are arranged in a complex spatial network, build-up the observed total\ncolumn density, and contain the dense cores and protostars in this cloud. Our\nresults demonstrate that the presence of fibers is not restricted to low-mass\nclouds but can be extended to regions of increasing mass and complexity. We\npropose that the observational dichotomy between clustered and non-clustered\nstar-forming regions might be naturally explained by the distinct spatial\ndensity of fertile fibers in these environments.\n",
"title": "Fibers in the NGC1333 proto-cluster"
}
| null | null |
[
"Physics"
] | null | true | null |
9543
| null |
Validated
| null | null |
null |
{
"abstract": " A common architecture for torque controlled humanoid robots consists in two\nnested loops. The outer loop generates desired joint/motor torques, and the\ninner loop stabilises these desired values. In doing so, the inner loop usually\ncompensates for joint friction phenomena, thus removing their inherent\nstabilising property that may be also beneficial for high level control\nobjectives. This paper shows how to exploit friction for joint and task space\ncontrol of humanoid robots. Experiments are carried out using the humanoid\nrobot iCub.\n",
"title": "Exploiting Friction in Torque Controlled Humanoid Robots"
}
| null | null | null | null | true | null |
9544
| null |
Default
| null | null |
null |
{
"abstract": " Actual causation is concerned with the question \"what caused what?\" Consider\na transition between two states within a system of interacting elements, such\nas an artificial neural network, or a biological brain circuit. Which\ncombination of synapses caused the neuron to fire? Which image features caused\nthe classifier to misinterpret the picture? Even detailed knowledge of the\nsystem's causal network, its elements, their states, connectivity, and dynamics\ndoes not automatically provide a straightforward answer to the \"what caused\nwhat?\" question. Counterfactual accounts of actual causation based on graphical\nmodels, paired with system interventions, have demonstrated initial success in\naddressing specific problem cases in line with intuitive causal judgments.\nHere, we start from a set of basic requirements for causation (realization,\ncomposition, information, integration, and exclusion) and develop a rigorous,\nquantitative account of actual causation that is generally applicable to\ndiscrete dynamical systems. We present a formal framework to evaluate these\ncausal requirements that is based on system interventions and partitions, and\nconsiders all counterfactuals of a state transition. This framework is used to\nprovide a complete causal account of the transition by identifying and\nquantifying the strength of all actual causes and effects linking the two\nconsecutive system states. Finally, we examine several exemplary cases and\nparadoxes of causation and show that they can be illuminated by the proposed\nframework for quantifying actual causation.\n",
"title": "What caused what? A quantitative account of actual causation using dynamical causal networks"
}
| null | null |
[
"Computer Science",
"Mathematics",
"Statistics"
] | null | true | null |
9545
| null |
Validated
| null | null |
null |
{
"abstract": " We consider the minimax setup for Gaussian one-armed bandit problem, i.e. the\ntwo-armed bandit problem with Gaussian distributions of incomes and known\ndistribution corresponding to the first arm. This setup naturally arises when\nthe optimization of batch data processing is considered and there are two\nalternative processing methods available with a priori known efficiency of the\nfirst method. One should estimate the efficiency of the second method and\nprovide predominant usage of the most efficient of both them. According to the\nmain theorem of the theory of games minimax strategy and minimax risk are\nsearched for as Bayesian ones corresponding to the worst-case prior\ndistribution. As a result, we obtain the recursive integro-difference equation\nand the second order partial differential equation in the limiting case as the\nnumber of batches goes to infinity. This makes it possible to determine minimax\nrisk and minimax strategy by numerical methods. If the number of batches is\nlarge enough we show that batch data processing almost does not influence the\ncontrol performance, i.e. the value of the minimax risk. Moreover, in case of\nBernoulli incomes and large number of batches, batch data processing provides\nalmost the same minimax risk as the optimal one-by-one data processing.\n",
"title": "Gaussian One-Armed Bandit and Optimization of Batch Data Processing"
}
| null | null | null | null | true | null |
9546
| null |
Default
| null | null |
null |
{
"abstract": " Machine learning has become pervasive in multiple domains, impacting a wide\nvariety of applications, such as knowledge discovery and data mining, natural\nlanguage processing, information retrieval, computer vision, social and health\ninformatics, ubiquitous computing, etc. Two essential problems of machine\nlearning are how to generate features and how to acquire labels for machines to\nlearn. Particularly, labeling large amount of data for each domain-specific\nproblem can be very time consuming and costly. It has become a key obstacle in\nmaking learning protocols realistic in applications. In this paper, we will\ndiscuss how to use the existing general-purpose world knowledge to enhance\nmachine learning processes, by enriching the features or reducing the labeling\nwork. We start from the comparison of world knowledge with domain-specific\nknowledge, and then introduce three key problems in using world knowledge in\nlearning processes, i.e., explicit and implicit feature representation,\ninference for knowledge linking and disambiguation, and learning with direct or\nindirect supervision. Finally we discuss the future directions of this research\ntopic.\n",
"title": "Machine Learning with World Knowledge: The Position and Survey"
}
| null | null | null | null | true | null |
9547
| null |
Default
| null | null |
null |
{
"abstract": " Indexes are models: a B-Tree-Index can be seen as a model to map a key to the\nposition of a record within a sorted array, a Hash-Index as a model to map a\nkey to a position of a record within an unsorted array, and a BitMap-Index as a\nmodel to indicate if a data record exists or not. In this exploratory research\npaper, we start from this premise and posit that all existing index structures\ncan be replaced with other types of models, including deep-learning models,\nwhich we term learned indexes. The key idea is that a model can learn the sort\norder or structure of lookup keys and use this signal to effectively predict\nthe position or existence of records. We theoretically analyze under which\nconditions learned indexes outperform traditional index structures and describe\nthe main challenges in designing learned index structures. Our initial results\nshow, that by using neural nets we are able to outperform cache-optimized\nB-Trees by up to 70% in speed while saving an order-of-magnitude in memory over\nseveral real-world data sets. More importantly though, we believe that the idea\nof replacing core components of a data management system through learned models\nhas far reaching implications for future systems designs and that this work\njust provides a glimpse of what might be possible.\n",
"title": "The Case for Learned Index Structures"
}
| null | null | null | null | true | null |
9548
| null |
Default
| null | null |
null |
{
"abstract": " We compute the leading Post-Newtonian (PN) contributions at quadratic order\nin the spins to the radiation-reaction acceleration and spin evolution for\nbinary systems, entering at four-and-a-half PN order. Our calculation includes\nthe back-reaction from finite-size spin effects, which is presented for the\nfirst time. The computation is carried out, from first principles, using the\neffective field theory framework for spinning extended objects. At this order,\nnonconservative effects in the spin-spin sector are independent of the spin\nsupplementary conditions. A non-trivial consistency check is performed by\nshowing that the energy loss induced by the resulting radiation-reaction force\nis equivalent to the total emitted power in the far zone. We find that, in\ncontrast to the spin-orbit contributions (reported in a companion paper), the\nradiation reaction affects the evolution of the spin vectors once spin-spin\neffects are incorporated.\n",
"title": "Radiation reaction for spinning bodies in effective field theory II: Spin-spin effects"
}
| null | null | null | null | true | null |
9549
| null |
Default
| null | null |
null |
{
"abstract": " Hybrid unmanned aircraft, that combine hover capability with a wing for fast\nand efficient forward flight, have attracted a lot of attention in recent\nyears. Many different designs are proposed, but one of the most promising is\nthe tailsitter concept. However, tailsitters are difficult to control across\nthe entire flight envelope, which often includes stalled flight. Additionally,\ntheir wing surface makes them susceptible to wind gusts. In this paper, we\npropose incremental nonlinear dynamic inversion control for the attitude and\nposition control. The result is a single, continuous controller, that is able\nto track the acceleration of the vehicle across the flight envelope. The\nproposed controller is implemented on the Cyclone hybrid UAV. Multiple outdoor\nexperiments are performed, showing that unmodeled forces and moments are\neffectively compensated by the incremental control structure, and that\naccelerations can be tracked across the flight envelope. Finally, we provide a\ncomprehensive procedure for the implementation of the controller on other types\nof hybrid UAVs.\n",
"title": "Incremental control and guidance of hybrid aircraft applied to the Cyclone tailsitter UAV"
}
| null | null | null | null | true | null |
9550
| null |
Default
| null | null |
null |
{
"abstract": " The harmonic product of tensors---leading to the concept of harmonic\nfactorization---has been defined in a previous work (Olive et al, 2017). In the\npractical case of 3D crack density measurements on thin or thick walled\nstructures, this mathematical tool allows us to factorize the harmonic\n(irreducible) part of the fourth-order damage tensor as an harmonic square: an\nexact harmonic square in 2D, an harmonic square over the set of so-called\nmechanically accessible directions for measurements in the 3D case. The\ncorresponding micro-mechanics framework based on second---instead of\nfourth---order damage tensors is derived. An illustrating example is provided\nshowing how the proposed framework allows for the modeling of the so-called\nhydrostatic sensitivity up to high damage levels.\n",
"title": "Micromechanics based framework with second-order damage tensors"
}
| null | null | null | null | true | null |
9551
| null |
Default
| null | null |
null |
{
"abstract": " Incorrect operations of a Multi-Robot System (MRS) may not only lead to\nunsatisfactory results, but can also cause economic losses and threats to\nsafety. These threats may not always be apparent, since they may arise as\nunforeseen consequences of the interactions between elements of the system.\nThis call for tools and techniques that can help in providing guarantees about\nMRSs behaviour. We think that, whenever possible, these guarantees should be\nbacked up by formal proofs to complement traditional approaches based on\ntesting and simulation.\nWe believe that tailored linguistic support to specify MRSs is a major step\ntowards this goal. In particular, reducing the gap between typical features of\nan MRS and the level of abstraction of the linguistic primitives would simplify\nboth the specification of these systems and the verification of their\nproperties. In this work, we review different agent-oriented languages and\ntheir features; we then consider a selection of case studies of interest and\nimplement them useing the surveyed languages. We also evaluate and compare\neffectiveness of the proposed solution, considering, in particular, easiness of\nexpressing non-trivial behaviour.\n",
"title": "Towards formal models and languages for verifiable Multi-Robot Systems"
}
| null | null | null | null | true | null |
9552
| null |
Default
| null | null |
null |
{
"abstract": " We show that the Revenue-Optimal Deterministic Mechanism Design problem for a\nsingle additive buyer is #P-hard, even when the distributions have support size\n2 for each item and, more importantly, even when the optimal solution is\nguaranteed to be of a very simple kind: the seller picks a price for each\nindividual item and a price for the grand bundle of all the items; the buyer\ncan purchase either the grand bundle at its given price or any subset of items\nat their total individual prices. The following problems are also #P-hard, as\nimmediate corollaries of the proof:\n1. determining if individual item pricing is optimal for a given instance,\n2. determining if grand bundle pricing is optimal, and\n3. computing the optimal (deterministic) revenue.\nOn the positive side, we show that when the distributions are i.i.d. with\nsupport size 2, the optimal revenue obtainable by any mechanism, even a\nrandomized one, can be achieved by a simple solution of the above kind\n(individual item pricing with a discounted price for the grand bundle) and\nfurthermore, it can be computed in polynomial time. The problem can be solved\nin polynomial time too when the number of items is constant.\n",
"title": "On the Complexity of Simple and Optimal Deterministic Mechanisms for an Additive Buyer"
}
| null | null | null | null | true | null |
9553
| null |
Default
| null | null |
null |
{
"abstract": " We present constraints on variations in the initial mass function (IMF) of\nnine local early-type galaxies based on their low mass X-ray binary (LMXB)\npopulations. Comprised of accreting black holes and neutron stars, these LMXBs\ncan be used to constrain the important high mass end of the IMF. We consider\nthe LMXB populations beyond the cores of the galaxies ($>0.2R_{e}$; covering\n$75-90\\%$ of their stellar light) and find no evidence for systematic\nvariations of the IMF with velocity dispersion ($\\sigma$). We reject IMFs which\nbecome increasingly bottom heavy with $\\sigma$, up to steep power-laws\n(exponent, $\\alpha>2.8$) in massive galaxies ($\\sigma>300$km/s), for\ngalactocentric radii $>1/4\\ R_{e}$. Previously proposed IMFs that become\nincreasingly bottom heavy with $\\sigma$ are consistent with these data if only\nthe number of low mass stars $(<0.5M_{\\odot}$) varies. We note that our results\nare consistent with some recent work which proposes that extreme IMFs are only\npresent in the central regions of these galaxies. We also consider IMFs that\nbecome increasingly top-heavy with $\\sigma$, resulting in significantly more\nLMXBs. Such a model is consistent with these observations, but additional data\nare required to significantly distinguish between this and an invariant IMF.\nFor six of these galaxies, we directly compare with published IMF mismatch\nparameters from the Atlas3D survey, $\\alpha_{dyn}$. We find good agreement with\nthe LMXB population if galaxies with higher $\\alpha_{dyn}$ have more top-heavy\nIMFs -- although we caution that our sample is quite small. Future LMXB\nobservations can provide further insights into the origin of $\\alpha_{dyn}$\nvariations.\n",
"title": "Further constraints on variations in the IMF from LMXB populations"
}
| null | null | null | null | true | null |
9554
| null |
Default
| null | null |
null |
{
"abstract": " We study static and spherically symmetric black hole (BH) solutions in\nsecond-order generalized Proca theories with nonminimal vector field derivative\ncouplings to the Ricci scalar, the Einstein tensor, and the double dual Riemann\ntensor. We find concrete Lagrangians which give rise to exact BH solutions by\nimposing two conditions of the two identical metric components and the constant\nnorm of the vector field. These exact solutions are described by either\nReissner-Nordström (RN), stealth Schwarzschild, or extremal RN solutions\nwith a non-trivial longitudinal mode of the vector field. We then numerically\nconstruct BH solutions without imposing these conditions. For cubic and quartic\nLagrangians with power-law couplings which encompass vector Galileons as the\nspecific cases, we show the existence of BH solutions with the difference\nbetween two non-trivial metric components. The quintic-order power-law\ncouplings do not give rise to non-trivial BH solutions regular throughout the\nhorizon exterior. The sixth-order and intrinsic vector-mode couplings can lead\nto BH solutions with a secondary hair. For all the solutions, the vector field\nis regular at least at the future or past horizon. The deviation from General\nRelativity induced by the Proca hair can be potentially tested by future\nmeasurements of gravitational waves in the nonlinear regime of gravity.\n",
"title": "Black holes in vector-tensor theories"
}
| null | null | null | null | true | null |
9555
| null |
Default
| null | null |
null |
{
"abstract": " This paper presents a reliable method to verify the existence of loops along\nthe uncertain trajectory of a robot, based on proprioceptive measurements only,\nwithin a bounded-error context. The loop closure detection is one of the key\npoints in SLAM methods, especially in homogeneous environments with difficult\nscenes recognitions. The proposed approach is generic and could be coupled with\nconventional SLAM algorithms to reliably reduce their computing burden, thus\nimproving the localization and mapping processes in the most challenging\nenvironments such as unexplored underwater extents.\nTo prove that a robot performed a loop whatever the uncertainties in its\nevolution, we employ the notion of topological degree that originates in the\nfield of differential topology. We show that a verification tool based on the\ntopological degree is an optimal method for proving robot loops. This is\ndemonstrated both on datasets from real missions involving autonomous\nunderwater vehicles, and by a mathematical discussion.\n",
"title": "Proving the existence of loops in robot trajectories"
}
| null | null | null | null | true | null |
9556
| null |
Default
| null | null |
null |
{
"abstract": " Chemical evolution is essential in understanding the origins of life. We\npresent a theory for the evolution of molecule masses and show that small\nmolecules grow by random diffusion and large molecules by a preferential\nattachment process leading eventually to life's molecules. It reproduces\ncorrectly the distribution of molecules found via mass spectroscopy for the\nMurchison meteorite and estimates the start of chemical evolution back to 12.8\nbillion years following the birth of stars and supernovae. From the Frontier\nmass between the random and preferential attachment dynamics the birth time of\nmolecule families can be estimated. Amino acids emerge about 165 million years\nafter the start of evolution. Using the scaling of reaction rates with the\ndistance of the molecules in space we recover correctly the few days emergence\ntime of amino acids in the Miller-Urey experiment. The distribution of\ninterstellar and extragalactic molecules are both consistent with the\nevolutionary mass distribution, and their age is estimated to 108 and 65\nmillion years after the start of evolution. From the model, we can determine\nthe number of different molecule compositions at the time of the creation of\nEarth to be 1.6 million and the number of molecule compositions in interstellar\nspace to a mere 719.\n",
"title": "The clock of chemical evolution"
}
| null | null | null | null | true | null |
9557
| null |
Default
| null | null |
null |
{
"abstract": " A simple, analytically correct algorithm is developed for calculating pencil\nbeam coordinates using the signals from an ideal cylindrical particle beam\nposition monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal\nwidths. The algorithm is then applied to simulations of realistic BPMs with\nfinite width PUEs. Surprisingly small deviations are found. Simple empirically\ndetermined correction terms reduce the deviations even further. The algorithm\nis then used to study the impact of beam-size upon the precision of BPMs in the\nnon-linear region. As an example of the data acquisition speed advantage, a\nFPGA-based BPM readout implementation of the new algorithm has been developed\nand characterized. Finally,the algorithm is tested with BPM data from the\nCornell Preinjector.\n",
"title": "Fast readout algorithm for cylindrical beam position monitors providing good accuracy for particle bunches with large offsets"
}
| null | null | null | null | true | null |
9558
| null |
Default
| null | null |
null |
{
"abstract": " A graph $G$ is called B$_k$-VPG (resp., B$_k$-EPG), for some constant $k\\geq\n0$, if it has a string representation on a grid such that each vertex is an\northogonal path with at most $k$ bends and two vertices are adjacent in $G$ if\nand only if the corresponding strings intersect (resp., the corresponding\nstrings share at least one grid edge). If two adjacent strings of a B$_k$-VPG\ngraph intersect exactly once, then the graph is called a one-string B$_k$-VPG\ngraph.\nIn this paper, we study the Maximum Independent Set and Minimum Dominating\nSet problems on B$_1$-VPG and B$_1$-EPG graphs. We first give a simple $O(\\log\nn)$-approximation algorithm for the Maximum Independent Set problem on\nB$_1$-VPG graphs, improving the previous $O((\\log n)^2)$-approximation\nalgorithm of Lahiri et al. (COCOA 2015). Then, we consider the Minimum\nDominating Set problem. We give an $O(1)$-approximation algorithm for this\nproblem on one-string B$_1$-VPG graphs, providing the first constant-factor\napproximation algorithm for this problem. Moreover, we show that the Minimum\nDominating Set problem is APX-hard on B$_1$-EPG graphs, ruling out the\npossibility of a PTAS unless P=NP. Finally, we give constant-factor\napproximation algorithms for this problem on two non-trivial subclasses of\nB$_1$-EPG graphs. To our knowledge, these are the first results for the Minimum\nDominating Set problem on B$_1$-EPG graphs, partially answering a question\nposed by Epstein et al. (WADS 2013).\n",
"title": "Approximation Algorithms for Independence and Domination on B$_1$-VPG and B$_1$-EPG Graphs"
}
| null | null |
[
"Computer Science"
] | null | true | null |
9559
| null |
Validated
| null | null |
null |
{
"abstract": " We study two identical fermions, or two hard-core bosons, in an infinite\nchain and coupled to phonons by interactions that modulate their hopping as\ndescribed by the Peierls/Su-Schrieffer-Heeger (SSH) model. We show that\nexchange of phonons generates effective nearest-neighbor repulsion between\nparticles and also gives rise to interactions that move the pair as a whole.\nThe two-polaron phase diagram exhibits two sharp transitions, leading to light\ndimers at strong coupling and the flattening of the dimer dispersion at some\ncritical values of the parameters. This dimer (quasi)self-trapping occurs at\ncoupling strengths where single polarons are mobile. This illustrates that,\ndepending on the strength of the phonon-mediated interactions, the coupling to\nphonons may completely suppress or strongly enhance quantum transport of\ncorrelated particles.\n",
"title": "Phonon-mediated repulsion, sharp transitions and (quasi)self-trapping in the extended Peierls-Hubbard model"
}
| null | null | null | null | true | null |
9560
| null |
Default
| null | null |
null |
{
"abstract": " Group synchronization requires to estimate unknown elements\n$({\\theta}_v)_{v\\in V}$ of a compact group ${\\mathfrak G}$ associated to the\nvertices of a graph $G=(V,E)$, using noisy observations of the group\ndifferences associated to the edges. This model is relevant to a variety of\napplications ranging from structure from motion in computer vision to graph\nlocalization and positioning, to certain families of community detection\nproblems.\nWe focus on the case in which the graph $G$ is the $d$-dimensional grid.\nSince the unknowns ${\\boldsymbol \\theta}_v$ are only determined up to a global\naction of the group, we consider the following weak recovery question. Can we\ndetermine the group difference ${\\theta}_u^{-1}{\\theta}_v$ between far apart\nvertices $u, v$ better than by random guessing? We prove that weak recovery is\npossible (provided the noise is small enough) for $d\\ge 3$ and, for certain\nfinite groups, for $d\\ge 2$. Viceversa, for some continuous groups, we prove\nthat weak recovery is impossible for $d=2$. Finally, for strong enough noise,\nweak recovery is always impossible.\n",
"title": "Group Synchronization on Grids"
}
| null | null |
[
"Mathematics",
"Statistics"
] | null | true | null |
9561
| null |
Validated
| null | null |
null |
{
"abstract": " Stability of power networks is an increasingly important topic because of the\nhigh penetration of renewable distributed generation units. This requires the\ndevelopment of advanced (typically model-based) techniques for the analysis and\ncontroller design of power networks. Although there are widely accepted\nreduced-order models to describe the dynamic behavior of power networks, they\nare commonly presented without details about the reduction procedure, hampering\nthe understanding of the physical phenomena behind them. The present paper aims\nto provide a modular model derivation of multi-machine power networks. Starting\nfrom first-principle fundamental physics, we present detailed dynamical models\nof synchronous machines and clearly state the underlying assumptions which lead\nto some of the standard reduced-order multi-machine models, including the\nclassical second-order swing equations. In addition, the energy functions for\nthe reduced-order multi-machine models are derived, which allows to represent\nthe multi-machine systems as port-Hamiltonian systems. Moreover, the systems\nare proven to be passive with respect to its steady states, which permits for a\npower-preserving interconnection with other passive components, including\npassive controllers. As a result, the corresponding energy function or\nHamiltonian can be used to provide a rigorous stability analysis of advanced\nmodels for the power network without having to linearize the system.\n",
"title": "An energy-based analysis of reduced-order models of (networked) synchronous machines"
}
| null | null | null | null | true | null |
9562
| null |
Default
| null | null |
null |
{
"abstract": " Since the majority of massive stars are members of binary systems, an\nunderstanding of the intricacies of binary interactions is essential for\nunderstanding the large variety of supernova types and sub-types. I therefore\nbriefly review the basic elements of binary evolution theory and discuss how\nbinary interactions affect the presupernova structure of massive stars and the\nresulting supernovae.\nSN 1987A was a highly anomalous supernova, almost certainly because of a\nprevious binary interaction. The most likely scenario at present is that the\nprogenitor was a member of a massive close binary that experienced dynamical\nmass transfer during its second red-supergiant phase and merged completely with\nits companion as a consequence. This can naturally explain the three main\nanomalies of SN 1987A: the blue color of the progenitor, the chemical anomalies\nand the complex triple-ring nebula.\n",
"title": "Binary Evolution and the Progenitor of SN 1987A"
}
| null | null |
[
"Physics"
] | null | true | null |
9563
| null |
Validated
| null | null |
null |
{
"abstract": " Networks observed in real world like social networks, collaboration networks\netc., exhibit temporal dynamics, i.e. nodes and edges appear and/or disappear\nover time. In this paper, we propose a generative, latent space based,\nstatistical model for such networks (called dynamic networks). We consider the\ncase where the number of nodes is fixed, but the presence of edges can vary\nover time. Our model allows the number of communities in the network to be\ndifferent at different time steps. We use a neural network based methodology to\nperform approximate inference in the proposed model and its simplified version.\nExperiments done on synthetic and real world networks for the task of community\ndetection and link prediction demonstrate the utility and effectiveness of our\nmodel as compared to other similar existing approaches.\n",
"title": "A Generative Model for Dynamic Networks with Applications"
}
| null | null | null | null | true | null |
9564
| null |
Default
| null | null |
null |
{
"abstract": " We investigate contextual online learning with nonparametric (Lipschitz)\ncomparison classes under different assumptions on losses and feedback\ninformation. For full information feedback and Lipschitz losses, we design the\nfirst explicit algorithm achieving the minimax regret rate (up to log factors).\nIn a partial feedback model motivated by second-price auctions, we obtain\nalgorithms for Lipschitz and semi-Lipschitz losses with regret bounds improving\non the known bounds for standard bandit feedback. Our analysis combines novel\nresults for contextual second-price auctions with a novel algorithmic approach\nbased on chaining. When the context space is Euclidean, our chaining approach\nis efficient and delivers an even better regret bound.\n",
"title": "Algorithmic Chaining and the Role of Partial Feedback in Online Nonparametric Learning"
}
| null | null |
[
"Mathematics",
"Statistics"
] | null | true | null |
9565
| null |
Validated
| null | null |
null |
{
"abstract": " We investigate the Robust Multiperiod Network Design Problem, a\ngeneralization of the classical Capacitated Network Design Problem that\nadditionally considers multiple design periods and provides solutions protected\nagainst traffic uncertainty. Given the intrinsic difficulty of the problem,\nwhich proves challenging even for state-of-the art commercial solvers, we\npropose a hybrid primal heuristic based on the combination of ant colony\noptimization and an exact large neighborhood search. Computational experiments\non a set of realistic instances from the SNDlib show that our heuristic can\nfind solutions of extremely good quality with low optimality gap.\n",
"title": "A hybrid primal heuristic for Robust Multiperiod Network Design"
}
| null | null | null | null | true | null |
9566
| null |
Default
| null | null |
null |
{
"abstract": " A deep learning architecture is proposed to predict graspable locations for\nrobotic manipulation. It considers situations where no, one, or multiple\nobject(s) are seen. By defining the learning problem to be classification with\nnull hypothesis competition instead of regression, the deep neural network with\nRGB-D image input predicts multiple grasp candidates for a single object or\nmultiple objects, in a single shot. The method outperforms state-of-the-art\napproaches on the Cornell dataset with 96.0% and 96.1% accuracy on image-wise\nand object- wise splits, respectively. Evaluation on a multi-object dataset\nillustrates the generalization capability of the architecture. Grasping\nexperiments achieve 96.0% grasp localization and 88.0% grasping success rates\non a test set of household objects. The real-time process takes less than .25 s\nfrom image to plan.\n",
"title": "Real-world Multi-object, Multi-grasp Detection"
}
| null | null |
[
"Computer Science"
] | null | true | null |
9567
| null |
Validated
| null | null |
null |
{
"abstract": " The fault tolerance of random graphs with unbounded degrees with respect to\nconnectivity is investigated. It is related to the reliability of wireless\nsensor networks with unreliable relay nodes. The model evaluates the network\nbreakdown probability that a graph is disconnected after stochastic node\nremoval. To establish a mean-field approximation for the model, the cavity\nmethod for finite systems is proposed. Then the asymptotic analysis is applied.\nAs a result, the former enables us to obtain an approximation formula for any\nnumber of nodes and an arbitrary and degree distribution. In addition, the\nlatter reveals that the phase transition occurs on random graphs with\nlogarithmic average degrees. Those results, which are supported by numerical\nsimulations, coincide with the mathematical results, indicating successful\npredictions by mean-field approximation for unbounded but not dense random\ngraphs.\n",
"title": "Fault Tolerance of Random Graphs with respect to Connectivity: Phase Transition in Logarithmic Average Degree"
}
| null | null |
[
"Physics"
] | null | true | null |
9568
| null |
Validated
| null | null |
null |
{
"abstract": " Factor graphs are important models for succinctly representing probability\ndistributions in machine learning, coding theory, and statistical physics.\nSeveral computational problems, such as computing marginals and partition\nfunctions, arise naturally when working with factor graphs. Belief propagation\nis a widely deployed iterative method for solving these problems. However,\ndespite its significant empirical success, not much is known about the\ncorrectness and efficiency of belief propagation.\nBethe approximation is an optimization-based framework for approximating\npartition functions. While it is known that the stationary points of the Bethe\napproximation coincide with the fixed points of belief propagation, in general,\nthe relation between the Bethe approximation and the partition function is not\nwell understood. It has been observed that for a few classes of factor graphs,\nthe Bethe approximation always gives a lower bound to the partition function,\nwhich distinguishes them from the general case, where neither a lower bound,\nnor an upper bound holds universally. This has been rigorously proved for\npermanents and for attractive graphical models.\nHere we consider bipartite normal factor graphs and show that if the local\nconstraints satisfy a certain analytic property, the Bethe approximation is a\nlower bound to the partition function. We arrive at this result by viewing\nfactor graphs through the lens of polynomials. In this process, we reformulate\nthe Bethe approximation as a polynomial optimization problem. Our sufficient\ncondition for the lower bound property to hold is inspired by recent\ndevelopments in the theory of real stable polynomials. We believe that this way\nof viewing factor graphs and its connection to real stability might lead to a\nbetter understanding of belief propagation and factor graphs in general.\n",
"title": "Belief Propagation, Bethe Approximation and Polynomials"
}
| null | null | null | null | true | null |
9569
| null |
Default
| null | null |
null |
{
"abstract": " The correct treatment of vibronic effects is vital for the modeling of\nabsorption spectra of solvated dyes, as many prominent spectral features can\noften be ascribed to vibronic transitions. Vibronic spectra can be computed\nwithin the Franck-Condon approximation for small dyes in solution using an\nimplicit solvent model. However, implicit solvent models neglect specific\nsolute-solvent interactions and provide only an approximate treatment of\nsolvent polarization effects. Furthermore, temperature-dependent solvent\nbroadening effects are often only accounted for using a broadening parameter\nchosen to match experimental spectra. On the other hand, ensemble approaches\nprovide a straightforward way of accounting for solute-solvent interactions and\ntemperature-dependent broadening effects by computing vertical excitation\nenergies obtained from an ensemble of solute-solvent conformations. However,\nensemble approaches do not explicitly account for vibronic effects and often\nproduce spectral shapes in poor agreement with experiment. We address these\nshortcomings by combining the vibronic fine structure of an excitation obtained\nin the Franck-Condon picture at zero temperature with vertical excitations\ncomputed for a room-temperature ensemble of solute-solvent configurations. In\nthis combined approach, all temperature-dependent broadening is therefore\ntreated classically through the sampling of configurations, with vibronic\ncontributions included as a zero-temperature correction to each vertical\ntransition. We test the proposed method on Nile Red and the green fluorescent\nprotein chromophore in polar and non-polar solvents. For systems with strong\nsolute-solvent interaction, the approach yields a significant improvement over\nthe ensemble approach, whereas for systems with weaker interactions, both the\nshape and the width of the spectra are in excellent agreement with experiment.\n",
"title": "Combining the Ensemble and Franck-Condon Approaches for Spectral Shapes of Molecules in Solution"
}
| null | null | null | null | true | null |
9570
| null |
Default
| null | null |
null |
{
"abstract": " Endowing a dialogue system with particular personality traits is essential to\ndeliver more human-like conversations. However, due to the challenge of\nembodying personality via language expression and the lack of large-scale\npersona-labeled dialogue data, this research problem is still far from\nwell-studied. In this paper, we investigate the problem of incorporating\nexplicit personality traits in dialogue generation to deliver personalized\ndialogues.\nTo this end, firstly, we construct PersonalDialog, a large-scale multi-turn\ndialogue dataset containing various traits from a large number of speakers. The\ndataset consists of 20.83M sessions and 56.25M utterances from 8.47M speakers.\nEach utterance is associated with a speaker who is marked with traits like Age,\nGender, Location, Interest Tags, etc. Several anonymization schemes are\ndesigned to protect the privacy of each speaker. This large-scale dataset will\nfacilitate not only the study of personalized dialogue generation, but also\nother researches on sociolinguistics or social science.\nSecondly, to study how personality traits can be captured and addressed in\ndialogue generation, we propose persona-aware dialogue generation models within\nthe sequence to sequence learning framework. Explicit personality traits\n(structured by key-value pairs) are embedded using a trait fusion module.\nDuring the decoding process, two techniques, namely persona-aware attention and\npersona-aware bias, are devised to capture and address trait-related\ninformation. Experiments demonstrate that our model is able to address proper\ntraits in different contexts. Case studies also show interesting results for\nthis challenging research problem.\n",
"title": "Personalized Dialogue Generation with Diversified Traits"
}
| null | null |
[
"Computer Science"
] | null | true | null |
9571
| null |
Validated
| null | null |
null |
{
"abstract": " Motivated by results of Mestre and Voisin, in this note we mainly consider\nabelian varieties isogenous to hyperelliptic Jacobians\nIn the first part we prove that a very general hyperelliptic Jacobian of\ngenus $g\\ge 4$ is not isogenous to a non-hyperelliptic Jacobian. As a\nconsequence we obtain that the Intermediate Jacobian of a very general cubic\nthreefold is not isogenous to a Jacobian. Another corollary tells that the\nJacobian of a very general $d$-gonal curve of genus $g \\ge 4$ is not isogenous\nto a different Jacobian.\nIn the second part we consider a closed subvariety $\\mathcal Y \\subset\n\\mathcal A_g$ of the moduli space of principally polarized varieties of\ndimension $g\\ge 3$. We show that if a very general element of $\\mathcal Y$ is\ndominated by a hyperelliptic Jacobian, then $\\dim \\mathcal Y\\ge 2g$. In\nparticular, if the general element in $\\mathcal Y$ is simple, its Kummer\nvariety does not contain rational curves. Finally we show that a closed\nsubvariety $\\mathcal Y\\subset \\mathcal M_g$ of dimension $2g-1$ such that the\nJacobian of a very general element of $\\mathcal Y$ is dominated by a\nhyperelliptic Jacobian is contained either in the hyperelliptic or in the\ntrigonal locus.\n",
"title": "Hyperelliptic Jacobians and isogenies"
}
| null | null | null | null | true | null |
9572
| null |
Default
| null | null |
null |
{
"abstract": " Orthogonal matching pursuit (OMP) and orthogonal least squares (OLS) are\nwidely used for sparse signal reconstruction in under-determined linear\nregression problems. The performance of these compressed sensing (CS)\nalgorithms depends crucially on the \\textit{a priori} knowledge of either the\nsparsity of the signal ($k_0$) or noise variance ($\\sigma^2$). Both $k_0$ and\n$\\sigma^2$ are unknown in general and extremely difficult to estimate in under\ndetermined models. This limits the application of OMP and OLS in many practical\nsituations. In this article, we develop two computationally efficient\nframeworks namely TF-IGP and RRT-IGP for using OMP and OLS even when $k_0$ and\n$\\sigma^2$ are unavailable. Both TF-IGP and RRT-IGP are analytically shown to\naccomplish successful sparse recovery under the same set of restricted isometry\nconditions on the design matrix required for OMP/OLS with \\textit{a priori}\nknowledge of $k_0$ and $\\sigma^2$. Numerical simulations also indicate a highly\ncompetitive performance of TF-IGP and RRT-IGP in comparison to OMP/OLS with\n\\textit{a priori} knowledge of $k_0$ and $\\sigma^2$.\n",
"title": "Signal and Noise Statistics Oblivious Sparse Reconstruction using OMP/OLS"
}
| null | null | null | null | true | null |
9573
| null |
Default
| null | null |
null |
{
"abstract": " Many physical problems involve spatial and temporal inhomogeneities that\nrequire a very fine discretization in order to be accurately simulated. Using\nan adaptive mesh, a high level of resolution is used in the appropriate areas\nwhile keeping a coarse mesh elsewhere. This idea allows to save time and\ncomputations, but represents a challenge for distributed-memory environments.\nThe MARS project (for Multiphase Adaptative Refinement Solver) intends to\nassess the parallel library p4est for adaptive mesh, in a case of a finite\nvolume scheme applied to two-phase flows. Besides testing the library's\nperformances, particularly for load balancing, its user-friendliness in use and\nimplementation are also exhibited here. First promising 3D simulations are even\npresented.\n",
"title": "Experimenting with the p4est library for AMR simulations of two-phase flows"
}
| null | null | null | null | true | null |
9574
| null |
Default
| null | null |
null |
{
"abstract": " The success of Conflict Driven Clause Learning (CDCL) for Boolean\nsatisfiability has inspired adoption in other domains. We present a novel\nlifting of CDCL to program analysis called Abstract Conflict Driven Learning\nfor Programs (ACDLP). ACDLP alternates between model search, which performs\nover-approximate deduction with constraint propagation, and conflict analysis,\nwhich performs under-approximate abduction with heuristic choice. We\ninstantiate the model search and conflict analysis algorithms to an abstract\ndomain of template polyhedra, strictly generalizing CDCL from the Boolean\nlattice to a richer lattice structure. Our template polyhedra can express\nintervals, octagons and restricted polyhedral constraints over program\nvariables. We have imple- mented ACDLP for automatic bounded safety\nverification of C programs. We evaluate the performance of our analyser by\ncomparing with CBMC, which uses CDCL, and Astree, a commercial abstract\ninterpretation tool. We observe two orders of magnitude reduction in the number\nof decisions, propagations, and conflicts as well as a 1.5x speedup in runtime\ncompared to CBMC. Compared to Astree, ACDLP solves twice as many benchmarks and\nhas much higher precision. This is the first instantiation of CDCL with a\ntemplate polyhedra abstract domain.\n",
"title": "Lifting CDCL to Template-based Abstract Domains for Program Verification"
}
| null | null | null | null | true | null |
9575
| null |
Default
| null | null |
null |
{
"abstract": " The paper provides an analysis of the voting method known as delegable proxy\nvoting, or liquid democracy. The analysis first positions liquid democracy\nwithin the theory of binary aggregation. It then focuses on two issues of the\nsystem: the occurrence of delegation cycles; and the effect of delegations on\nindividual rationality when voting on logically interdependent propositions. It\nfinally points to proposals on how the system may be modified in order to\naddress the above issues.\n",
"title": "Binary Voting with Delegable Proxy: An Analysis of Liquid Democracy"
}
| null | null | null | null | true | null |
9576
| null |
Default
| null | null |
null |
{
"abstract": " At the exceptional point where two eigenstates coalesce in open quantum\nsystems, the usual diagonalization scheme breaks down and the Hamiltonian can\nonly be reduced to Jordan block form. Most of the studies on the exceptional\npoint appearing in the literature introduce a phenomenological effective\nHamiltonian that essentially reduces the problem to that of a finite\nnon-Hermitian matrix for which it is straightforward to obtain the Jordan form.\nIn this paper, we demonstrate how the Hamiltonian of an open quantum system\nreduces to Jordan block form at an exceptional point in an exact manner that\ntreats the continuum without any approximation. Our method relies on the\nBrillouin-Wigner-Feshbach projection method according to which we can obtain a\nfinite dimensional effective Hamiltonian that shares the discrete sector of the\nspectrum with the original Hamiltonian. While owing to its eigenvalue\ndependence this effective Hamiltonian cannot be used to write the Jordan block\ndirectly, we show that by formally extending the problem to include eigenstates\nwith complex eigenvalues that reside outside the usual Hilbert space, we can\nobtain the Jordan block form at the exceptional point without introducing any\napproximation. We also introduce an extended Jordan form basis away from the\nexceptional point, which provides an alternative way to obtain the Jordan block\nat an exceptional point. The extended Jordan block connects continuously to the\nJordan block exactly at the exceptional point implying that the observable\nquantities are continuous at the exceptional point.\n",
"title": "Exact description of coalescing eigenstates in open quantum systems in terms of microscopic Hamiltonian dynamics"
}
| null | null |
[
"Physics"
] | null | true | null |
9577
| null |
Validated
| null | null |
null |
{
"abstract": " The main topic considered is maximizing the number of cycles in a graph with\ngiven number of edges. In 2009, Király conjectured that there is constant $c$\nsuch that any graph with $m$ edges has at most $(1.4)^m$ cycles. In this paper,\nit is shown that for sufficiently large $m$, a graph with $m$ edges has at most\n$(1.443)^m$ cycles. For sufficiently large $m$, examples of a graph with $m$\nedges and $(1.37)^m$ cycles are presented. For a graph with given number of\nvertices and edges an upper bound on the maximal number of cycles is given.\nAlso, exponentially tight bounds are proved for the maximum number of cycles in\na multigraph with given number of edges, as well as in a multigraph with given\nnumber of vertices and edges.\n",
"title": "The maximum number of cycles in a graph with fixed number of edges"
}
| null | null |
[
"Mathematics"
] | null | true | null |
9578
| null |
Validated
| null | null |
null |
{
"abstract": " The article introduces a new concept of structure, defined, echoing J. A.\nWheeler's concept of \"law without law,\" as a \"structure without law,\" and a new\nphilosophical viewpoint, that of structural nnnrealism, and considers how this\nconcept and this viewpoint work in quantum theory in general and quantum\ninformation theory in particular. It takes as its historical point of departure\nW. Heisenberg's discovery of quantum mechanics, which, the article argues,\ncould, in retrospect, be considered in quantum-informational terms, while,\nconversely, quantum information theory could be seen in Heisenbergian terms.\nThe article takes advantage of the circumstance that any instance of quantum\ninformation is a \"structure\"--an organization of elements, ultimately bits, of\nclassical information, manifested in measuring instruments. While, however,\nthis organization can, along with the observed behavior of measuring\ninstruments, be described by means of classical physics, it cannot be predicted\nby means of classical physics, but only, probabilistically or statistically, by\nmeans of quantum mechanics, or in high-energy physics, by means of quantum\nfield theory (or possibly some alternative theories within each scope). By\ncontrast, the emergences of this information and of this structure cannot, in\nthe present view, be described by either classical or quantum theory, or\npossibly by any other means, which leads to the concept of \"structure without\nlaw\" and the viewpoint of structural nnnrealism. The article also considers,\nfrom this perspective, some recent work in quantum information theory.\n",
"title": "Structural Nonrealism and Quantum Information"
}
| null | null | null | null | true | null |
9579
| null |
Default
| null | null |
null |
{
"abstract": " Robots state of insecurity is onstage. There is an emerging concern about\nmajor robot vulnerabilities and their adverse consequences. However, there is\nstill a considerable gap between robotics and cybersecurity domains. For the\npurpose of filling that gap, the present technical report presents the Robotics\nCTF (RCTF), an online playground to challenge robot security from any browser.\nWe describe the architecture of the RCTF and provide 9 scenarios where hackers\ncan challenge the security of different robotic setups. Our work empowers\nsecurity researchers to a) reproduce virtual robotic scenarios locally and b)\nchange the networking setup to mimic real robot targets. We advocate for hacker\npowered security in robotics and contribute by open sourcing our scenarios.\n",
"title": "Robotics CTF (RCTF), a playground for robot hacking"
}
| null | null | null | null | true | null |
9580
| null |
Default
| null | null |
null |
{
"abstract": " Tungsten (W) is widely considered as the most promising plasma facing\nmaterial, which is used in nuclear fusion devices. During the operation of the\nnuclear fusion devices, transmutation elements, such as Re, Os, and Ta, are\ngenerated in W due to the transmutation reaction under fusion neutron\nirradiation. In this paper, we investigated the effects of the transmutation\nelements on the mechanical properties of W and the behavior of hydrogen/helium\n(H/He) atom in W by using the rst principles calculation method. The results\nare that the generation of the transmutation elements can enhance the ductility\nof W without considering the dislocation and other defects, and this phenomenon\nis called as solution toughen. However, there is not a strict linear\nrelationship between the change of the mechanical properties and the\ntransmutation elements concentration. Compared with the H/He atom in pure W,\nthe formation energy of the H/He in W are decreased by the transmutation\nelements, but the transmutation elements does not change the most favorable\nsites for H/He in W. An attractive interaction exists between the transmutation\nelements and H/He in W, while a repulsive interaction exists between Ta and He\nin W. The best diffusion path H/He in W is changed due to the interaction\nbetween the transmutation elements and H/He. All of the above results provide\nimportant information for application of W as the plasma facing material in the\nnuclear fusion devices.\n",
"title": "Effects of transmutation elements in tungsten as a plasma facing material"
}
| null | null | null | null | true | null |
9581
| null |
Default
| null | null |
null |
{
"abstract": " Consider a (not necessarily near-critical) random graph running in continuous\ntime. A recent breadth-first-walk construction is extended in order to account\nfor the surplus edge data in addition to the spanning edge data. Two different\ngraph representations of the multiplicative coalescent, with different\nadvantages and drawbacks, are discussed in detail. A canonical multi-graph of\nBhamidi, Budhiraja and Wang (2014) naturally emerges. The presented framework\nshould facilitate understanding of scaling limits with surplus edges for\nnear-critical random graphs in the domain of attraction of general (not\nnecessarily standard) eternal multiplicative coalescent.\n",
"title": "A playful note on spanning and surplus edges"
}
| null | null | null | null | true | null |
9582
| null |
Default
| null | null |
null |
{
"abstract": " Designing a logo for a new brand is a lengthy and tedious back-and-forth\nprocess between a designer and a client. In this paper we explore to what\nextent machine learning can solve the creative task of the designer. For this,\nwe build a dataset -- LLD -- of 600k+ logos crawled from the world wide web.\nTraining Generative Adversarial Networks (GANs) for logo synthesis on such\nmulti-modal data is not straightforward and results in mode collapse for some\nstate-of-the-art methods. We propose the use of synthetic labels obtained\nthrough clustering to disentangle and stabilize GAN training. We are able to\ngenerate a high diversity of plausible logos and we demonstrate latent space\nexploration techniques to ease the logo design task in an interactive manner.\nMoreover, we validate the proposed clustered GAN training on CIFAR 10,\nachieving state-of-the-art Inception scores when using synthetic labels\nobtained via clustering the features of an ImageNet classifier. GANs can cope\nwith multi-modal data by means of synthetic labels achieved through clustering,\nand our results show the creative potential of such techniques for logo\nsynthesis and manipulation. Our dataset and models will be made publicly\navailable at this https URL.\n",
"title": "Logo Synthesis and Manipulation with Clustered Generative Adversarial Networks"
}
| null | null | null | null | true | null |
9583
| null |
Default
| null | null |
null |
{
"abstract": " We study the notion of consistency between a 3D shape and a 2D observation\nand propose a differentiable formulation which allows computing gradients of\nthe 3D shape given an observation from an arbitrary view. We do so by\nreformulating view consistency using a differentiable ray consistency (DRC)\nterm. We show that this formulation can be incorporated in a learning framework\nto leverage different types of multi-view observations e.g. foreground masks,\ndepth, color images, semantics etc. as supervision for learning single-view 3D\nprediction. We present empirical analysis of our technique in a controlled\nsetting. We also show that this approach allows us to improve over existing\ntechniques for single-view reconstruction of objects from the PASCAL VOC\ndataset.\n",
"title": "Multi-view Supervision for Single-view Reconstruction via Differentiable Ray Consistency"
}
| null | null |
[
"Computer Science"
] | null | true | null |
9584
| null |
Validated
| null | null |
null |
{
"abstract": " Rank minimization (RM) is a wildly investigated task of finding solutions by\nexploiting low-rank structure of parameter matrices. Recently, solving RM\nproblem by leveraging non-convex relaxations has received significant\nattention. It has been demonstrated by some theoretical and experimental work\nthat non-convex relaxation, e.g. Truncated Nuclear Norm Regularization (TNNR)\nand Reweighted Nuclear Norm Regularization (RNNR), can provide a better\napproximation of original problems than convex relaxations. However, designing\nan efficient algorithm with theoretical guarantee remains a challenging\nproblem. In this paper, we propose a simple but efficient proximal-type method,\nnamely Iterative Shrinkage-Thresholding Algorithm(ISTA), with concrete analysis\nto solve rank minimization problems with both non-convex weighted and\nreweighted nuclear norm as low-rank regularizers. Theoretically, the proposed\nmethod could converge to the critical point under very mild assumptions with\nthe rate in the order of $O(1/T)$. Moreover, the experimental results on both\nsynthetic data and real world data sets show that proposed algorithm\noutperforms state-of-arts in both efficiency and accuracy.\n",
"title": "Efficient Rank Minimization via Solving Non-convexPenalties by Iterative Shrinkage-Thresholding Algorithm"
}
| null | null | null | null | true | null |
9585
| null |
Default
| null | null |
null |
{
"abstract": " We study properties of the Stanley-Reisner rings of simplicial complexes with\nisolated singularities modulo two generic linear forms. Miller, Novik, and\nSwartz proved that if a complex has homologically isolated singularities, then\nits Stanley-Reisner ring modulo one generic linear form is Buchsbaum. Here we\nexamine the case of non-homologically isolated singularities, providing many\nexamples in which the Stanley-Reisner ring modulo two generic linear forms is a\nquasi-Buchsbaum but not Buchsbaum ring.\n",
"title": "Almost Buchsbaumness of some rings arising from complexes with isolated singularities"
}
| null | null | null | null | true | null |
9586
| null |
Default
| null | null |
null |
{
"abstract": " We propose and analyze theoretically an approach for realizing a tunable\noptical phased-array antenna utilizing the properties of VO2 for electronic\nbeam steering applications in the near-IR spectral range. The device is based\non a 1D array of slot nano-antennas engraved in a thin Au film grown over VO2\nlayer. The tuning is obtained by inducing a temperature gradient over the\ndevice, which changes the refractive index of the VO2, and hence modifies the\nphase response of the elements comprising the array, by producing a thermal\ngradient within the underlying PCM layer. Using a 10-element array, we show\nthat an incident beam can be steered up to with respect to the normal, by\napplying a gradient of less than 10°C.\n",
"title": "Dynamically controlled plasmonic nano-antenna phased array utilizing vanadium dioxide"
}
| null | null | null | null | true | null |
9587
| null |
Default
| null | null |
null |
{
"abstract": " Human visual object recognition is typically rapid and seemingly effortless,\nas well as largely independent of viewpoint and object orientation. Until very\nrecently, animate visual systems were the only ones capable of this remarkable\ncomputational feat. This has changed with the rise of a class of computer\nvision algorithms called deep neural networks (DNNs) that achieve human-level\nclassification performance on object recognition tasks. Furthermore, a growing\nnumber of studies report similarities in the way DNNs and the human visual\nsystem process objects, suggesting that current DNNs may be good models of\nhuman visual object recognition. Yet there clearly exist important\narchitectural and processing differences between state-of-the-art DNNs and the\nprimate visual system. The potential behavioural consequences of these\ndifferences are not well understood. We aim to address this issue by comparing\nhuman and DNN generalisation abilities towards image degradations. We find the\nhuman visual system to be more robust to image manipulations like contrast\nreduction, additive noise or novel eidolon-distortions. In addition, we find\nprogressively diverging classification error-patterns between humans and DNNs\nwhen the signal gets weaker, indicating that there may still be marked\ndifferences in the way humans and current DNNs perform visual object\nrecognition. We envision that our findings as well as our carefully measured\nand freely available behavioural datasets provide a new useful benchmark for\nthe computer vision community to improve the robustness of DNNs and a\nmotivation for neuroscientists to search for mechanisms in the brain that could\nfacilitate this robustness.\n",
"title": "Comparing deep neural networks against humans: object recognition when the signal gets weaker"
}
| null | null | null | null | true | null |
9588
| null |
Default
| null | null |
null |
{
"abstract": " We discuss dynamical response functions near quantum critical points,\nallowing for both a finite temperature and detuning by a relevant operator.\nWhen the quantum critical point is described by a conformal field theory (CFT),\nconformal perturbation theory and the operator product expansion can be used to\nfix the first few leading terms at high frequencies. Knowledge of the high\nfrequency response allows us then to derive non-perturbative sum rules. We\nshow, via explicit computations, how holography recovers the general results of\nCFT, and the associated sum rules, for any holographic field theory with a\nconformal UV completion -- regardless of any possible new ordering and/or\nscaling physics in the IR. We numerically obtain holographic response functions\nat all frequencies, allowing us to probe the breakdown of the asymptotic\nhigh-frequency regime. Finally, we show that high frequency response functions\nin holographic Lifshitz theories are quite similar to their conformal\ncounterparts, even though they are not strongly constrained by symmetry.\n",
"title": "Quantum critical response: from conformal perturbation theory to holography"
}
| null | null | null | null | true | null |
9589
| null |
Default
| null | null |
null |
{
"abstract": " We study testing high-dimensional covariance matrices under a generalized\nelliptical model. The model accommodates several stylized facts of real data\nincluding heteroskedasticity, heavy-tailedness, asymmetry, etc. We consider the\nhigh-dimensional setting where the dimension $p$ and the sample size $n$ grow\nto infinity proportionally, and establish a central limit theorem for the\n{linear spectral statistic} of the sample covariance matrix based on\nself-normalized observations. The central limit theorem is different from the\nexisting ones for the linear spectral statistic of the usual sample covariance\nmatrix. Our tests based on the new central limit theorem neither assume a\nspecific parametric distribution nor involve the kurtosis of data. Simulation\nstudies show that our tests work well even when the fourth moment does not\nexist. Empirically, we analyze the idiosyncratic returns under the Fama-French\nthree-factor model for S\\&P 500 Financials sector stocks, and our tests reject\nthe hypothesis that the idiosyncratic returns are uncorrelated.\n",
"title": "Testing High-dimensional Covariance Matrices under the Elliptical Distribution and Beyond"
}
| null | null | null | null | true | null |
9590
| null |
Default
| null | null |
null |
{
"abstract": " While there exist several successful techniques for supporting programmers in\nderiving static resource bounds for sequential code, analyzing the resource\nusage of message-passing concurrent processes poses additional challenges. To\nmeet these challenges, this article presents an analysis for statically\nderiving worst-case bounds on the total work performed by message-passing\nprocesses. To decompose interacting processes into components that can be\nanalyzed in isolation, the analysis is based on novel resource-aware session\ntypes, which describe protocols and resource contracts for inter-process\ncommunication. A key innovation is that both messages and processes carry\npotential to share and amortize cost while communicating. To symbolically\nexpress resource usage in a setting without static data structures and\nintrinsic sizes, resource contracts describe bounds that are functions of\ninteractions between processes. Resource-aware session types combine standard\nbinary session types and type-based amortized resource analysis in a linear\ntype system. This type system is formulated for a core session-type calculus of\nthe language SILL and proved sound with respect to a multiset-based operational\ncost semantics that tracks the total number of messages that are exchanged in a\nsystem. The effectiveness of the analysis is demonstrated by analyzing standard\nexamples from amortized analysis and the literature on session types and by a\ncomparative performance analysis of different concurrent programs implementing\nthe same interface.\n",
"title": "Work Analysis with Resource-Aware Session Types"
}
| null | null | null | null | true | null |
9591
| null |
Default
| null | null |
null |
{
"abstract": " We show that a certain family of cohomogeneity one manifolds does not admit\nan invariant metric of nonnegative sectional curvature, unless it admits one\nwith positive curvature. As a consequence, the classification of nonnegatively\ncurved cohomogeneity one manifolds in dimension 7 is reduced to only one\nfurther family of candidates\n",
"title": "Seven dimensional cohomogeneity one manifolds with nonnegative curvature"
}
| null | null |
[
"Mathematics"
] | null | true | null |
9592
| null |
Validated
| null | null |
null |
{
"abstract": " We investigate regularized algorithms combining with projection for\nleast-squares regression problem over a Hilbert space, covering nonparametric\nregression over a reproducing kernel Hilbert space. We prove convergence\nresults with respect to variants of norms, under a capacity assumption on the\nhypothesis space and a regularity condition on the target function. As a\nresult, we obtain optimal rates for regularized algorithms with randomized\nsketches, provided that the sketch dimension is proportional to the effective\ndimension up to a logarithmic factor. As a byproduct, we obtain similar results\nfor Nyström regularized algorithms. Our results are the first ones with\noptimal, distribution-dependent rates that do not have any saturation effect\nfor sketched/Nyström regularized algorithms, considering both the\nattainable and non-attainable cases.\n",
"title": "Optimal Rates of Sketched-regularized Algorithms for Least-Squares Regression over Hilbert Spaces"
}
| null | null | null | null | true | null |
9593
| null |
Default
| null | null |
null |
{
"abstract": " In this paper, we study the scaling properties of Legendre polynomials Pn(x).\nWe show that Pn(ax), where a is a constant, can be expanded as a sum of either\nLegendre polynomials Pn(x) or their multiple derivatives dkPn(x)/dxk, and we\nderive a general expression for the expansion coefficients. In addition, we\ndemonstrate that the multiple derivative dkPn(x)/dxk can also be expressed as a\nsum of Legendre polynomials and we obtain a recurrence relation for the\ncoefficients.\n",
"title": "The scaling properties and the multiple derivative of Legendre polynomials"
}
| null | null |
[
"Mathematics"
] | null | true | null |
9594
| null |
Validated
| null | null |
null |
{
"abstract": " An important problem in machine learning and statistics is to identify\nfeatures that causally affect the outcome. This is often impossible to do from\npurely observational data, and a natural relaxation is to identify features\nthat are correlated with the outcome even conditioned on all other observed\nfeatures. For example, we want to identify that smoking really is correlated\nwith cancer conditioned on demographics. The knockoff procedure is a recent\nbreakthrough in statistics that, in theory, can identify truly correlated\nfeatures while guaranteeing that the false discovery is limited. The idea is to\ncreate synthetic data -knockoffs- that captures correlations amongst the\nfeatures. However there are substantial computational and practical challenges\nto generating and using knockoffs. This paper makes several key advances that\nenable knockoff application to be more efficient and powerful. We develop an\nefficient algorithm to generate valid knockoffs from Bayesian Networks. Then we\nsystematically evaluate knockoff test statistics and develop new statistics\nwith improved power. The paper combines new mathematical guarantees with\nsystematic experiments on real and synthetic data.\n",
"title": "Knockoffs for the mass: new feature importance statistics with false discovery guarantees"
}
| null | null | null | null | true | null |
9595
| null |
Default
| null | null |
null |
{
"abstract": " We report all phases and corresponding critical lines of the quantum\nanisotropic transverse XY model with Dzyaloshinskii-Moriya (DM) interaction\nalong with uniform and alternating transverse magnetic fields (ATXY) by using\nappropriately chosen order parameters. We prove that when DM interaction is\nweaker than the anisotropy parameter, it has no effect at all on the\nzero-temperature states of the XY model with uniform transverse magnetic field\nwhich is not the case for the ATXY model. However, when DM interaction is\nstronger than the anisotropy parameter, we show appearance of a new gapless\nphase - a chiral phase - in the XY model with uniform as well as alternating\nfield. We further report that first derivatives of nearest neighbor two-site\nentanglement with respect to magnetic fields can detect all the critical lines\npresent in the system. We also observe that the factorization surface at\nzero-temperature present in this model without DM interaction becomes a volume\non the introduction of the later. We find that DM interaction can generate\nbipartite entanglement sustainable at large times, leading to a proof of\nergodic nature of bipartite entanglement in this system, and can induce a\ntransition from non-monotonicity of entanglement with temperature to a\nmonotonic one.\n",
"title": "Phase boundaries in alternating field quantum XY model with Dzyaloshinskii-Moriya interaction: Sustainable entanglement in dynamics"
}
| null | null | null | null | true | null |
9596
| null |
Default
| null | null |
null |
{
"abstract": " Categorical equivalences between block algebras of finite groups - such as\nMorita and derived equivalences - are well-known to induce character bijections\nwhich commute with the Galois groups of field extensions. This is the\nmotivation for attempting to realise known Morita and derived equivalences over\nnon splitting fields. This article presents various result on the theme of\ndescent. We start with the observation that perfect isometries induced by a\nvirtual Morita equivalence induce isomorphisms of centers in non-split\nsituations, and explain connections with Navarro's generalisation of the\nAlperin-McKay conjecture. We show that Rouquier's splendid Rickard complex for\nblocks with cyclic defect groups descends to the non-split case. We also prove\na descent theorem for Morita equivalences with endopermutation source.\n",
"title": "Descent of equivalences and character bijections"
}
| null | null | null | null | true | null |
9597
| null |
Default
| null | null |
null |
{
"abstract": " In the arithmetic of function fields, Drinfeld modules play the role that\nelliptic curves play in the arithmetic of number fields. The aim of this paper\nis to study a non-existence problem of Drinfeld modules with constrains on\ntorsion points at places with large degree. This is motivated by a conjecture\nof Christopher Rasmussen and Akio Tamagawa on the non-existence of abelian\nvarieties over number fields with some arithmetic constraints. We prove the\nnon-existence of Drinfeld modules satisfying Rasmussen-Tamagawa type conditions\nin the case where the inseparable degree of base fields is not divisible by the\nrank of Drinfeld modules. Conversely if the rank divides the inseparable\ndegree, then we give an example of Drinfeld modules satisfying\nRasmussen-Tamagawa-type conditions.\n",
"title": "A function field analogue of the Rasmussen-Tamagawa conjecture: The Drinfeld module case"
}
| null | null |
[
"Mathematics"
] | null | true | null |
9598
| null |
Validated
| null | null |
null |
{
"abstract": " In this paper, we explore the effectiveness of dynamic analysis techniques\nfor identifying malware, using Hidden Markov Models (HMMs) and Profile Hidden\nMarkov Models (PHMMs), both trained on sequences of API calls. We contrast our\nresults to static analysis using HMMs trained on sequences of opcodes, and show\nthat dynamic analysis achieves significantly stronger results in many cases.\nFurthermore, in contrasting our two dynamic analysis techniques, we find that\nusing PHMMs consistently outperforms our analysis based on HMMs.\n",
"title": "Malware Detection Using Dynamic Birthmarks"
}
| null | null | null | null | true | null |
9599
| null |
Default
| null | null |
null |
{
"abstract": " This note is concerned with accurate and computationally efficient\napproximations of moments of Gaussian random variables passed through sigmoid\nor softmax mappings. These approximations are semi-analytical (i.e. they\ninvolve the numerical adjustment of parametric forms) and highly accurate (they\nyield 5% error at most). We also highlight a few niche applications of these\napproximations, which arise in the context of, e.g., drift-diffusion models of\ndecision making or non-parametric data clustering approaches. We provide these\nas examples of efficient alternatives to more tedious derivations that would be\nneeded if one was to approach the underlying mathematical issues in a more\nformal way. We hope that this technical note will be helpful to modellers\nfacing similar mathematical issues, although maybe stemming from different\nacademic prospects.\n",
"title": "Semi-analytical approximations to statistical moments of sigmoid and softmax mappings of normal variables"
}
| null | null | null | null | true | null |
9600
| null |
Default
| null | null |
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