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null | {
"abstract": " Using a (1+2)-dimensional boson-vortex duality between non-linear\nelectrodynamics and a two-component compressible Bose-Einstein condensate (BEC)\nwith spin-orbit (SO) coupling, we obtain generalised versions of the\nhydrodynamic continuity and Euler equations where the phase defect and\nnon-defect degrees of freedom enter separately. We obtain the generalised\nMagnus force on vortices under SO coupling, and associate the linear\nconfinement of vortices due to SO coupling with instanton fluctuations of the\ndual theory.\n",
"title": "Boson-vortex duality in compressible spin-orbit coupled BECs"
} | null | null | [
"Physics"
]
| null | true | null | 18501 | null | Validated | null | null |
null | {
"abstract": " A new coding technique, based on \\textit{fixed block-length} codes, is\nproposed for the problem of communicating a pair of correlated sources over a\n$2-$user interference channel. Its performance is analyzed to derive a new set\nof sufficient conditions. The latter is proven to be strictly less binding than\nthe current known best, which is due to Liu and Chen [Dec, 2011]. Our findings\nare inspired by Dueck's example [March, 1981].\n",
"title": "Communicating Correlated Sources Over an Interference Channel"
} | null | null | null | null | true | null | 18502 | null | Default | null | null |
null | {
"abstract": " Transport of excitations along proteins can be formulated in a quantum\nphysics context, based on the periodicity and vibrational modes of the\nstructures. Exact solutions are very challenging to obtain on classical\ncomputers, however, approximate solutions based on the Davydov ansatz have\ndemonstrated the possibility of stabilized solitonic excitations along the\nprotein. We propose an alternative study based on a chain of ultracold atoms.\nWe investigate the experimental parameters to control such a quantum simulator\nbased on dressed Rydberg atoms. We show that there is a feasible range of\nparameters where a quantum simulator can directly mimic the Davydov equations\nand their solutions. Such a quantum simulator opens up new directions for the\nstudy of transport phenomena in a biophysical context.\n",
"title": "Simulating polaron biophysics with Rydberg atoms"
} | null | null | [
"Physics"
]
| null | true | null | 18503 | null | Validated | null | null |
null | {
"abstract": " Solubility of dyes in amphiphilic association structures of water, SDS and\npenthanol system (i.e. in the phases of microemulsions and liquid crystals) was\nattracted much interest due to its wide industrial and technological\napplications. This research was focused on understanding the solubility\nlimitation of methyl red and methylene blue in microemulsion and liquid crystal\nphases. Experimental results showed that the highest solubility of methyl red\nwas in LLC, followed by w/o microemulsion and o/w microemulsion, respectively,\nwhereas the highest solubility of methylene blue was in w/o microemulsion,\nfollowed by o/w microemulsion and LLC, respectively. Hence, a chemical dynamics\nstrongly played an important role in the solubility limitation of methyl red\nand methylene blue in microemulsions and liquid crystal phases.\n",
"title": "Solubility limit of methyl red and methylene blue in microemulsions and liquid crystals of water, sds and pentanol systems"
} | null | null | [
"Physics"
]
| null | true | null | 18504 | null | Validated | null | null |
null | {
"abstract": " Many model-based Visual Odometry (VO) algorithms have been proposed in the\npast decade, often restricted to the type of camera optics, or the underlying\nmotion manifold observed. We envision robots to be able to learn and perform\nthese tasks, in a minimally supervised setting, as they gain more experience.\nTo this end, we propose a fully trainable solution to visual ego-motion\nestimation for varied camera optics. We propose a visual ego-motion learning\narchitecture that maps observed optical flow vectors to an ego-motion density\nestimate via a Mixture Density Network (MDN). By modeling the architecture as a\nConditional Variational Autoencoder (C-VAE), our model is able to provide\nintrospective reasoning and prediction for ego-motion induced scene-flow.\nAdditionally, our proposed model is especially amenable to bootstrapped\nego-motion learning in robots where the supervision in ego-motion estimation\nfor a particular camera sensor can be obtained from standard navigation-based\nsensor fusion strategies (GPS/INS and wheel-odometry fusion). Through\nexperiments, we show the utility of our proposed approach in enabling the\nconcept of self-supervised learning for visual ego-motion estimation in\nautonomous robots.\n",
"title": "Towards Visual Ego-motion Learning in Robots"
} | null | null | null | null | true | null | 18505 | null | Default | null | null |
null | {
"abstract": " Prediction of popularity has profound impact for social media, since it\noffers opportunities to reveal individual preference and public attention from\nevolutionary social systems. Previous research, although achieves promising\nresults, neglects one distinctive characteristic of social data, i.e.,\nsequentiality. For example, the popularity of online content is generated over\ntime with sequential post streams of social media. To investigate the\nsequential prediction of popularity, we propose a novel prediction framework\ncalled Deep Temporal Context Networks (DTCN) by incorporating both temporal\ncontext and temporal attention into account. Our DTCN contains three main\ncomponents, from embedding, learning to predicting. With a joint embedding\nnetwork, we obtain a unified deep representation of multi-modal user-post data\nin a common embedding space. Then, based on the embedded data sequence over\ntime, temporal context learning attempts to recurrently learn two adaptive\ntemporal contexts for sequential popularity. Finally, a novel temporal\nattention is designed to predict new popularity (the popularity of a new\nuser-post pair) with temporal coherence across multiple time-scales.\nExperiments on our released image dataset with about 600K Flickr photos\ndemonstrate that DTCN outperforms state-of-the-art deep prediction algorithms,\nwith an average of 21.51% relative performance improvement in the popularity\nprediction (Spearman Ranking Correlation).\n",
"title": "Sequential Prediction of Social Media Popularity with Deep Temporal Context Networks"
} | null | null | null | null | true | null | 18506 | null | Default | null | null |
null | {
"abstract": " In the smart grid, smart meters, and numerous control and monitoring\napplications employ bidirectional wireless communication, where security is a\ncritical issue. In key management based encryption method for the smart grid,\nthe Trusted Third Party (TTP), and links between the smart meter and the third\nparty are assumed to be fully trusted and reliable. However, in wired/wireless\nmedium, a man-in-middle may want to interfere, monitor and control the network,\nthus exposing its vulnerability. Acknowledging this, in this paper, we propose\na novel two level encryption method based on two partially trusted simple\nservers (constitutes the TTP) which implement this method without increasing\npacket overhead. One server is responsible for data encryption between the\nmeter and control center/central database, and the other server manages the\nrandom sequence of data transmission. Numerical calculation shows that the\nnumber of iterations required to decode a message is large which is quite\nimpractical. Furthermore, we introduce One-class support vector machine\n(machine learning) algorithm for node-to-node authentication utilizing the\nlocation information and the data transmission history (node identity, packet\nsize and frequency of transmission). This secures data communication privacy\nwithout increasing the complexity of the conventional key management scheme.\n",
"title": "Key Management and Learning based Two Level Data Security for Metering Infrastructure of Smart Grid"
} | null | null | [
"Computer Science"
]
| null | true | null | 18507 | null | Validated | null | null |
null | {
"abstract": " We consider the homogeneous equation ${\\mathcal A} u=0$, where ${\\mathcal A}$\nis a symmetric and coercive elliptic operator in $H^1(\\Omega)$ with $\\Omega$\nbounded domain in ${\\mathbb R}^d$. The boundary conditions involve fractional\npower $\\alpha$, $ 0 < \\alpha <1$, of the Steklov spectral operator arising in\nDirichlet to Neumann map. For such problems we discuss two different numerical\nmethods: (1) a computational algorithm based on an approximation of the\nintegral representation of the fractional power of the operator and (2)\nnumerical technique involving an auxiliary Cauchy problem for an\nultra-parabolic equation and its subsequent approximation by a time stepping\ntechnique. For both methods we present numerical experiment for a model\ntwo-dimensional problem that demonstrate the accuracy, efficiency, and\nstability of the algorithms.\n",
"title": "A numerical study of the homogeneous elliptic equation with fractional order boundary conditions"
} | null | null | null | null | true | null | 18508 | null | Default | null | null |
null | {
"abstract": " Crowded environments modify the diffusion of macromolecules, generally\nslowing their movement and inducing transient anomalous subdiffusion. The\npresence of obstacles also modifies the kinetics and equilibrium behavior of\ntracers. While previous theoretical studies of particle diffusion have\ntypically assumed either impenetrable obstacles or binding interactions that\nimmobilize the particle, in many cellular contexts bound particles remain\nmobile. Examples include membrane proteins or lipids with some entry and\ndiffusion within lipid domains and proteins that can enter into membraneless\norganelles or compartments such as the nucleolus. Using a lattice model, we\nstudied the diffusive movement of tracer particles which bind to soft\nobstacles, allowing tracers and obstacles to occupy the same lattice site. For\nsticky obstacles, bound tracer particles are immobile, while for slippery\nobstacles, bound tracers can hop without penalty to adjacent obstacles. In both\nmodels, binding significantly alters tracer motion. The type and degree of\nmotion while bound is a key determinant of the tracer mobility: slippery\nobstacles can allow nearly unhindered diffusion, even at high obstacle filling\nfraction. To mimic compartmentalization in a cell, we examined how obstacle\nsize and a range of bound diffusion coefficients affect tracer dynamics. The\nbehavior of the model is similar in two and three spatial dimensions. Our work\nhas implications for protein movement and interactions within cells.\n",
"title": "Effects of soft interactions and bound mobility on diffusion in crowded environments: a model of sticky and slippery obstacles"
} | null | null | null | null | true | null | 18509 | null | Default | null | null |
null | {
"abstract": " We study the effect of coupling a spin bath environment to a system which, at\nlow energies, can be modeled as a quantum Ising system. A field theoretic\nformalism incorporating both thermal and quantum fluctuations is developed to\nderive results for the thermodynamic properties and response functions, both\nfor a toy model and for the $LiHoF_4$ system, in which spin-8 electronic spins\ncouple to a spin-$7/2$ nuclear spin bath: the phase transition then occurs in a\nsystem of electronuclear degrees of freedom, coupled by long-range dipolar\ninteractions. The quantum Ising phase transition still exists, and one\nhybridized mode of the Ising and bath spins always goes soft at the transition.\n",
"title": "Thermodynamics of a Quantum Ising system coupled to a spin bath: Zero Temperature Results"
} | null | null | null | null | true | null | 18510 | null | Default | null | null |
null | {
"abstract": " The quest for large and low frequency band gaps is one of the principal\nobjectives pursued in a number of engineering applications, ranging from noise\nabsorption to vibration control, to seismic wave abatement. For this purpose, a\nplethora of complex architectures (including multi-phase materials) and\nmulti-physics approaches have been proposed in the past, often involving\ndifficulties in their practical realization.\nTo address this issue, in this work we propose an easy-to-manufacture design\nable to open large, low frequency complete Lamb band gaps exploiting a suitable\narrangement of masses and stiffnesses produced by cavities in a monolithic\nmaterial. The performance of the designed structure is evaluated by numerical\nsimulations and confirmed by Scanning Laser Doppler Vibrometer (SLDV)\nmeasurements on an isotropic polyvinyl chloride plate in which a square ring\nregion of cross-like cavities is fabricated. The full wave field reconstruction\nclearly confirms the ability of even a limited number of unit cell rows of the\nproposed design to efficiently attenuate Lamb waves. In addition, numerical\nsimulations show that the structure allows to shift of the central frequency of\nthe BG through geometrical modifications. The design may be of interest for\napplications in which large BGs at low frequencies are required.\n",
"title": "Observation of a Lamb band gap in a polymer waveguide with periodic cross-like cavities"
} | null | null | null | null | true | null | 18511 | null | Default | null | null |
null | {
"abstract": " A search for instability of nucleons bound in $^{136}$Xe nuclei is reported\nwith 223 kg$\\cdot$yr exposure of $^{136}$Xe in the EXO-200 experiment. Lifetime\nlimits of 3.3$\\times 10^{23}$ and 1.9$\\times 10^{23}$ yrs are established for\nnucleon decay to $^{133}$Sb and $^{133}$Te, respectively. These are the most\nstringent to date, exceeding the prior decay limits by a factor of 9 and 7,\nrespectively.\n",
"title": "Search for nucleon decays with EXO-200"
} | null | null | null | null | true | null | 18512 | null | Default | null | null |
null | {
"abstract": " Massive stars like company. Here, we provide a brief overview of progresses\nmade over the last 5 years by a number of medium and large surveys. These\nresults provide new insights on the observed and intrinsic multiplicity\nproperties of main sequence massive stars and on the initial conditions for\ntheir future evolution. They also bring new interesting constraints on the\noutcome of the massive star formation process.\n",
"title": "The multiplicity of massive stars: a 2016 view"
} | null | null | [
"Physics"
]
| null | true | null | 18513 | null | Validated | null | null |
null | {
"abstract": " We analyze the behavior of the eigenvalues of the following non local mixed\nproblem $\\left\\{ \\begin{array}{rcll} (-\\Delta)^{s} u &=& \\lambda_1(D) \\ u\n&\\inn\\Omega,\\\\ u&=&0&\\inn D,\\\\ \\mathcal{N}_{s}u&=&0&\\inn N. \\end{array}\\right $\nOur goal is to construct different sequences of problems by modifying the\nconfiguration of the sets $D$ and $N$, and to provide sufficient and necessary\nconditions on the size and the location of these sets in order to obtain\nsequences of eigenvalues that in the limit recover the eigenvalues of the\nDirichlet or Neumann problem. We will see that the non locality plays a crucial\nrole here, since the sets $D$ and $N$ can have infinite measure, a phenomenon\nthat does not appear in the local case (see for example \\cite{D,D2,CP}).\n",
"title": "Principal Eigenvalue of Mixed Problem for the Fractional Laplacian: Moving the Boundary Conditions"
} | null | null | null | null | true | null | 18514 | null | Default | null | null |
null | {
"abstract": " Using a formalism based on the two-body S-matrix we study two-dimensional\nBose and Fermi gases with both attractive and repulsive interactions.\nApproximate analytic expressions, valid at weak coupling and beyond, are\ndeveloped and applied to the Berezinskii-Kosterlitz-Thouless (BKT) transition.\nWe successfully recover the correct logarithmic functional form of the critical\nchemical potential and density for the Bose gas. For fermions, the BKT critical\ntemperature is calculated in BCS and BEC regimes through consideration of Tan's\ncontact.\n",
"title": "Two-dimensional Bose and Fermi gases beyond weak coupling"
} | null | null | null | null | true | null | 18515 | null | Default | null | null |
null | {
"abstract": " Sr$_2$RuO$_4$ is the best candidate for spin-triplet superconductivity, an\nunusual and elusive superconducting state of fundamental importance. In the\nlast three decades Sr$_2$RuO$_4$ has been very carefully studied and despite\nits apparent simplicity when compared with strongly correlated high-$T_{c}$\ncuprates, for which the pairing symmetry is understood, there is no scenario\nthat can explain all the major experimental observations, a conundrum that has\ngenerated tremendous interest. Here we present a density-functional based\nanalysis of magnetic interactions in Sr$_{2}$RuO$_{4}$ and discuss the role of\nmagnetic anisotropy in its unconventional superconductivity. Our goal is\ntwofold. First, we access the possibility of the superconducting order\nparameter rotation in an external magnetic field of 200 Oe, and conclude that\nthe spin-orbit interaction in this material is several orders of magnitude too\nstrong to be consistent with this hypothesis. Thus, the observed invariance of\nthe Knight shift across $T_{c}$ has no plausible explanation, and casts doubt\non using the Knight shift as an ultimate litmus paper for the pairing symmetry.\nSecond, we propose a quantitative double-exchange-like model for combining\nitinerant fermions with an anisotropic Heisenberg magnetic Hamiltonian. This\nmodel is complementary to the Hubbard-model-based calculations published so\nfar, and forms an alternative framework for exploring superconducting symmetry\nin Sr$_{2}$RuO$_{4}.$ As an example, we use this model to analyze the\ndegeneracy between various $p-$triplet states in the simplest mean-field\napproximation, and show that it splits into a single and two doublets with the\nground state defined by the competition between the \"Ising\" and \"compass\"\nanisotropic terms.\n",
"title": "Anisotropy of magnetic interactions and symmetry of the order parameter in unconventional superconductor Sr$_{2}$RuO$_{4}$"
} | null | null | null | null | true | null | 18516 | null | Default | null | null |
null | {
"abstract": " We are concerned with the regularity of solutions of the Lighthill problem\nfor shock diffraction by a convex corned wedge, which can be formulated as a\nfree boundary problem. In this paper, we prove that there is no regular\nsolution that is subsonic up to the wedge corner for potential flow. This\nindicates that, if the solution is subsonic at the wedge corner, at least a\ncharacteristic discontinuity (vortex sheet or entropy wave) is expected to be\ngenerated, which is consistent with the experimental and computational results.\nIn order to achieve the non-existence result, a weak maximum principle for the\nsolution is established, and several other mathematical techniques are\ndeveloped. The methods and techniques developed here are also useful to the\nother problems with similar difficulties.\n",
"title": "Loss of Regularity of Solutions of the Lighthill Problem for Shock Diffraction for Potential Flow"
} | null | null | null | null | true | null | 18517 | null | Default | null | null |
null | {
"abstract": " The European Space Agency (ESA) defines an Earth Observation (EO) Level 2\nproduct as a multispectral (MS) image corrected for geometric, atmospheric,\nadjacency and topographic effects, stacked with its scene classification map\n(SCM), whose legend includes quality layers such as cloud and cloud-shadow. No\nESA EO Level 2 product has ever been systematically generated at the ground\nsegment. To contribute toward filling an information gap from EO big data to\nthe ESA EO Level 2 product, an original Stage 4 validation (Val) of the\nSatellite Image Automatic Mapper (SIAM) lightweight computer program was\nconducted by independent means on an annual Web-Enabled Landsat Data (WELD)\nimage composite time-series of the conterminous U.S. The core of SIAM is a one\npass prior knowledge based decision tree for MS reflectance space\nhyperpolyhedralization into static color names presented in literature in\nrecent years. For the sake of readability this paper is split into two. The\npresent Part 1 Theory provides the multidisciplinary background of a priori\ncolor naming in cognitive science, from linguistics to computer vision. To cope\nwith dictionaries of MS color names and land cover class names that do not\ncoincide and must be harmonized, an original hybrid guideline is proposed to\nidentify a categorical variable pair relationship. An original quantitative\nmeasure of categorical variable pair association is also proposed. The\nsubsequent Part 2 Validation discusses Stage 4 Val results collected by an\noriginal protocol for wall-to-wall thematic map quality assessment without\nsampling where the test and reference map legends can differ. Conclusions are\nthat the SIAM-WELD maps instantiate a Level 2 SCM product whose legend is the 4\nclass taxonomy of the FAO Land Cover Classification System at the Dichotomous\nPhase Level 1 vegetation/nonvegetation and Level 2 terrestrial/aquatic.\n",
"title": "Stage 4 validation of the Satellite Image Automatic Mapper lightweight computer program for Earth observation Level 2 product generation, Part 1 Theory"
} | null | null | null | null | true | null | 18518 | null | Default | null | null |
null | {
"abstract": " The Minimum Error Correction (MEC) approach is used as a metric for\nreconstruction of haplotypes from NGS reads. In this paper, we show that the\nMEC may encounter with imprecise reconstructed haplotypes for some NGS devices.\nSpecifically, using mathematical derivations, we evaluate this approach for the\nSOLiD, Illumina, 454, Ion, Pacific BioSciences, Oxford Nanopore, and 10X\nGenomics devices. Our results reveal that the MEC yields inexact haplotypes for\nthe Illumina MiniSeq, 454 GS Junior+, Ion PGM 314, and Oxford Nanopore MK 1\nMinION.\n",
"title": "Performance Analysis of MEC Approach for Haplotype Assembly"
} | null | null | null | null | true | null | 18519 | null | Default | null | null |
null | {
"abstract": " We present opinion recommendation, a novel task of jointly predicting a\ncustom review with a rating score that a certain user would give to a certain\nproduct or service, given existing reviews and rating scores to the product or\nservice by other users, and the reviews that the user has given to other\nproducts and services. A characteristic of opinion recommendation is the\nreliance of multiple data sources for multi-task joint learning, which is the\nstrength of neural models. We use a single neural network to model users and\nproducts, capturing their correlation and generating customised product\nrepresentations using a deep memory network, from which customised ratings and\nreviews are constructed jointly. Results show that our opinion recommendation\nsystem gives ratings that are closer to real user ratings on Yelp.com data\ncompared with Yelp's own ratings, and our methods give better results compared\nto several pipelines baselines using state-of-the-art sentiment rating and\nsummarization systems.\n",
"title": "Opinion Recommendation using Neural Memory Model"
} | null | null | null | null | true | null | 18520 | null | Default | null | null |
null | {
"abstract": " We formulate an optimization problem for maximizing the data rate of a common\nmessage transmitted from nodes within an airborne network broadcast to a\ncentral station receiver while maintaining a set of intra-network rate demands.\nAssuming that the network has full-duplex links with multi-beam directional\ncapability, we obtain a convex multi-commodity flow problem and use a\ndistributed augmented Lagrangian algorithm to solve for the optimal flows\nassociated with each beam in the network. For each augmented Lagrangian\niteration, we propose a scaled gradient projection method to minimize the local\nLagrangian function that incorporates the local topology of each node in the\nnetwork. Simulation results show fast convergence of the algorithm in\ncomparison to simple distributed primal dual methods and highlight performance\ngains over standard minimum distance-based routing.\n",
"title": "Distributed Optimization of Multi-Beam Directional Communication Networks"
} | null | null | null | null | true | null | 18521 | null | Default | null | null |
null | {
"abstract": " We propose boundary conditions for the diffusion equation that maintain the\ninitial mean and the total mass of a discrete data sample in the density\nestimation process. A complete study of this framework with numerical\nexperiments using the finite element method is presented for the one\ndimensional diffusion equation, some possible applications of this results are\npresented as well. We also comment on a similar methodology for the\ntwo-dimensional diffusion equation for future applications in two-dimensional\ndomains.\n",
"title": "Mean conservation for density estimation via diffusion using the finite element method"
} | null | null | null | null | true | null | 18522 | null | Default | null | null |
null | {
"abstract": " We consider a stable Cox--Ingersoll--Ross process driven by a standard Wiener\nprocess and a spectrally positive strictly stable Lévy process, and we study\nasymptotic properties of the maximum likelihood estimator (MLE) for its growth\nrate based on continuous time observations. We distinguish three cases:\nsubcritical, critical and supercritical. In all cases we prove strong\nconsistency of the MLE in question, in the subcritical case asymptotic\nnormality, and in the supercritical case asymptotic mixed normality are shown\nas well. In the critical case the description of the asymptotic behavior of the\nMLE in question remains open.\n",
"title": "Asymptotic properties of maximum likelihood estimator for the growth rate of a stable CIR process based on continuous time observations"
} | null | null | null | null | true | null | 18523 | null | Default | null | null |
null | {
"abstract": " This paper presents millimeter wave (mmWave) penetration loss measurements\nand analysis at 73 GHz using a wideband sliding correlator channel sounder in\nan indoor office environment. Penetration loss was measured using a carefully\ncontrolled measurement setup for many common indoor building materials such as\nglass doors, glass windows, closet doors, steel doors, and whiteboard writing\nwalls. Measurements were conducted using narrowbeam transmitter (TX) and\nreceiver (RX) horn antennas that were boresight-aligned with a test material\nbetween the antennas. Overall, 21 different locations were measured for 6\ndifferent materials such that the same type of material was tested in at least\ntwo locations in order to characterize the effect of penetration loss for\nmaterials with similar composition. As shown here, attenuation through common\nmaterials ranged between 0.8 dB/cm and 9.9 dB/cm for co-polarized antennas,\nwhile cross-polarized antennas exhibited similar attenuation for most\nmaterials, but up to 23.4 dB/cm of attenuation for others. The penetration loss\nresults presented here are useful for site-specific planning tools that will\nmodel indoor mmWave networks, without the need for expensive measurement\ncampaigns.\n",
"title": "Indoor Office Wideband Penetration Loss Measurements at 73 GHz"
} | null | null | [
"Computer Science"
]
| null | true | null | 18524 | null | Validated | null | null |
null | {
"abstract": " The electron spectrometer, SPEDE, has been developed and will be employed in\nconjunction with the Miniball spectrometer at the HIE-ISOLDE facility, CERN.\nSPEDE allows for direct measurement of internal conversion electrons emitted\nin-flight, without employing magnetic fields to transport or momentum filter\nthe electrons. Together with the Miniball spectrometer, it enables simultaneous\nobservation of {\\gamma} rays and conversion electrons in Coulomb-excitation\nexperiments using radioactive ion beams.\n",
"title": "The SPEDE spectrometer"
} | null | null | null | null | true | null | 18525 | null | Default | null | null |
null | {
"abstract": " A control design approach is developed for a general class of uncertain\nstrict-feedback-like nonlinear systems with dynamic uncertain input\nnonlinearities with time delays. The system structure considered in this paper\nincludes a nominal uncertain strict-feedback-like subsystem, the input signal\nto which is generated by an uncertain nonlinear input unmodeled dynamics that\nis driven by the entire system state (including unmeasured state variables) and\nis also allowed to depend on time delayed versions of the system state variable\nand control input signals. The system also includes additive uncertain\nnonlinear functions, coupled nonlinear appended dynamics, and uncertain dynamic\ninput nonlinearities with time-varying uncertain time delays. The proposed\ncontrol design approach provides a globally stabilizing delay-independent\nrobust adaptive output-feedback dynamic controller based on a dual dynamic\nhigh-gain scaling based structure.\n",
"title": "Global Stabilization of Triangular Systems with Time-Delayed Dynamic Input Perturbations"
} | null | null | null | null | true | null | 18526 | null | Default | null | null |
null | {
"abstract": " We introduce a pipeline including multifractal detrended cross-correlation\nanalysis (MF-DXA) modified by either singular value decomposition or the\nadaptive method to examine the statistical properties of the pulsar timing\nresidual ($PTR$) induced by a gravitational wave (GW) signal. We propose a new\nalgorithm, the so-called irregular-MF-DXA, to deal with irregular data\nsampling. Inspired by the quadrupolar nature of the spatial cross-correlation\nfunction of a gravitational wave background, a new cross-correlation function,\n$\\bar{\\sigma}_{\\times}$, derived from irregular-MF-DXA will be introduced. We\nshow that, this measure reveals the quadrupolar signature in the $PTRs$ induced\nby stochastic GWB. We propose four strategies based on the $y$-intercept of\nfluctuation functions, the generalized Hurst exponent, and the width of the\nsingularity spectrum to determine the dimensionless amplitude and power-law\nexponent of the characteristic strain spectrum as\n$\\mathcal{H}_c(f)\\sim\\mathcal{A}_{yr}(f/f_{yr})^{\\zeta}$ for stochastic GWB.\nUsing the value of Hurst exponent, one can clarify the type of GWs. We apply\nour pipeline to explore 20 millisecond pulsars observed by Parkes Pulsar Timing\nArray. The computed scaling exponents confirm that all data are classified into\na nonstationary class implying the universality feature. The value of the Hurst\nexponent is in the range $H\\in [0.56,0.87]$. The $q$-dependency of the\ngeneralized Hurst exponent demonstrates that the observed $PTRs$ have\nmultifractal behavior, and the source of this multifractality is mainly\nattributed to the correlation of data which is another universality of the\nobserved datasets. Multifractal analysis of available $PTRs$ datasets reveals\nan upper bound on the dimensionless amplitude of the GWB, $\\mathcal{A}_{yr}<\n2.0\\times 10^{-15}$.\n",
"title": "Multifractal Analysis of Pulsar Timing Residuals: Assessment of Gravitational Wave Detection"
} | null | null | null | null | true | null | 18527 | null | Default | null | null |
null | {
"abstract": " The goal of the OSIRIS-REx mission is to return a sample of asteroid material\nfrom Near-Earth Asteroid (101955) Bennu. The role of the navigation and flight\ndynamics team is critical for the spacecraft to execute a precisely planned\nsampling maneuver over a specifically-selected landing site. In particular, the\norientation of Bennu needs to be recovered with good accuracy during orbital\noperations to contribute as small an error as possible to the landing error\nbudget. Although Bennu is well characterized from Earth-based radar\nobservations, its orientation dynamics are not sufficiently known to exclude\nthe presence of a small wobble. To better understand this contingency and\nevaluate how well the orientation can be recovered in the presence of a large\n1$^{\\circ}$ wobble, we conduct a comprehensive simulation with the NASA GSFC\nGEODYN orbit determination and geodetic parameter estimation software. We\ndescribe the dynamic orientation modeling implemented in GEODYN in support of\nOSIRIS-REx operations, and show how both altimetry and imagery data can be used\nas either undifferenced (landmark, direct altimetry) or differenced (image\ncrossover, altimetry crossover) measurements. We find that these two different\ntypes of data contribute differently to the recovery of instrument pointing or\nplanetary orientation. When upweighted, the absolute measurements help reduce\nthe geolocation errors, despite poorer astrometric (inertial) performance. We\nfind that with no wobble present, all the geolocation requirements are met.\nWhile the presence of a large wobble is detrimental, the recovery is still\nreliable thanks to the combined use of altimetry and imagery data.\n",
"title": "Recovery of Bennu's Orientation for the OSIRIS-REx Mission: Implications for the Spin State Accuracy and Geolocation Errors"
} | null | null | null | null | true | null | 18528 | null | Default | null | null |
null | {
"abstract": " We modify the standard relativistic dispersion relation in a way which breaks\nLorentz symmetry - the effect is predicted in a high-energy regime of some\nmodern theories of quantum gravity. We show that it is possible to realise this\nscenario within the framework of Rainbow Gravity which introduces two new\nenergy-dependent functions $f_1(E)$ and $f_2(E)$ into the dispersion relation.\nAdditionally, we assume that the gravitational constant $G$ and the\ncosmological constant $\\Lambda$ also depend on energy $E$ and introduce the\nscaling function $h(E)$ in order to express this dependence. For cosmological\napplications we specify the functions $f_1$ and $f_2$ in order to fit massless\nparticles which allows us to derive modified cosmological equations. Finally,\nby using Hubble+SNIa+BAO(BOSS+Lyman $\\alpha$)+CMB data, we constrain the energy\nscale $E_{LV}$ to be at least of the order of $10^{16}$ GeV at $1\\sigma$ which\nis the GUT scale or even higher $10^{17}$ GeV at $3\\sigma$. Our claim is that\nthis energy can be interpreted as the decoupling scale of massless particles\nfrom spacetime Lorentz violating effects.\n",
"title": "Energy Scale of Lorentz Violation in Rainbow Gravity"
} | null | null | [
"Physics"
]
| null | true | null | 18529 | null | Validated | null | null |
null | {
"abstract": " We present an algorithm for construction step wavelets on local fields of\npositive characteristic.\n",
"title": "How to construct wavelets on local fields of positive characteristic"
} | null | null | null | null | true | null | 18530 | null | Default | null | null |
null | {
"abstract": " Fragmentation of filaments into dense cores is thought to be an important\nstep in forming stars. The bar-mode instability of spherically collapsing cores\nfound in previous linear analysis invokes a possibility of re-fragmentation of\nthe cores due to their ellipsoidal (prolate or oblate) deformation. To\ninvestigate this possibility, here we perform three-dimensional\nself-gravitational hydrodynamics simulations that follow all the way from\nfilament fragmentation to subsequent core collapse. We assume the gas is\npolytropic with index \\gamma, which determines the stability of the bar-mode.\nFor the case that the fragmentation of isolated hydrostatic filaments is\ntriggered by the most unstable fragmentation mode, we find the bar mode grows\nas collapse proceeds if \\gamma < 1.1, in agreement with the linear analysis.\nHowever, it takes more than ten orders-of-magnitude increase in the central\ndensity for the distortion to become non-linear. In addition to this fiducial\ncase, we also study non-fiducial ones such as the fragmentation is triggered by\na fragmentation mode with a longer wavelength and it occurs during radial\ncollapse of filaments and find the distortion rapidly grows. In most of\nastrophysical applications, the effective polytropic index of collapsing gas\nexceeds 1.1 before ten orders-of-magnitude increase in the central density.\nThus, supposing the fiducial case of filament fragmentation, re-fragmentation\nof dense cores would not be likely and their final mass would be determined\nwhen the filaments fragment.\n",
"title": "Fates of the dense cores formed by fragmentation of filaments: do they fragment again or not?"
} | null | null | null | null | true | null | 18531 | null | Default | null | null |
null | {
"abstract": " What transpires from recent research is that temperatures and radiative\nforcing seem to be characterized by a linear trend with two changes in the rate\nof growth. The first occurs in the early 60s and indicates a very large\nincrease in the rate of growth of both temperature and radiative forcing\nseries. This was termed as the \"onset of sustained global warming\". The second\nis related to the more recent so-called hiatus period, which suggests that\ntemperatures and total radiative forcing have increased less rapidly since the\nmid-90s compared to the larger rate of increase from 1960 to 1990. There are\ntwo issues that remain unresolved. The first is whether the breaks in the slope\nof the trend functions of temperatures and radiative forcing are common. This\nis important because common breaks coupled with the basic science of climate\nchange would strongly suggest a causal effect from anthropogenic factors to\ntemperatures. The second issue relates to establishing formally via a proper\ntesting procedure that takes into account the noise in the series, whether\nthere was indeed a `hiatus period' for temperatures since the mid 90s. This is\nimportant because such a test would counter the widely held view that the\nhiatus is the product of natural internal variability. Our paper provides tests\nrelated to both issues. The results show that the breaks in temperatures and\nradiative forcing are common and that the hiatus is characterized by a\nsignificant decrease in their rate of growth. The statistical results are of\nindependent interest and applicable more generally.\n",
"title": "Inference Related to Common Breaks in a Multivariate System with Joined Segmented Trends with Applications to Global and Hemispheric Temperatures"
} | null | null | null | null | true | null | 18532 | null | Default | null | null |
null | {
"abstract": " This paper studies problems on locally stopping distributed consensus\nalgorithms over networks where each node updates its state by interacting with\nits neighbors and decides by itself whether certain level of agreement has been\nachieved among nodes. Since an individual node is unable to access the states\nof those beyond its neighbors, this problem becomes challenging. In this work,\nwe first define the stopping problem for generic distributed algorithms. Then,\na distributed algorithm is explicitly provided for each node to stop consensus\nupdating by exploring the relationship between the so-called local and global\nconsensus. Finally, we show both in theory and simulation that its\neffectiveness depends both on the network size and the structure.\n",
"title": "How to Stop Consensus Algorithms, locally?"
} | null | null | [
"Computer Science"
]
| null | true | null | 18533 | null | Validated | null | null |
null | {
"abstract": " We present the characteristics and the performance of the new CCD camera\nsystem, SNUCAM-II (Seoul National University CAMera system II) that was\ninstalled on the Lee Sang Gak Telescope (LSGT) at the Siding Spring Observatory\nin 2016. SNUCAM-II consists of a deep depletion chip covering a wide wavelength\nfrom 0.3 {\\mu}m to 1.1 {\\mu}m with high sensitivity (QE at > 80% over 0.4 to\n0.9 {\\mu}m). It is equipped with the SDSS ugriz filters and 13 medium band\nwidth (50 nm) filters, enabling us to study spectral energy distributions\n(SEDs) of diverse objects from extragalactic sources to solar system objects.\nOn LSGT, SNUCAM-II offers 15.7 {\\times} 15.7 arcmin field-of-view (FOV) at a\npixel scale of 0.92 arcsec and a limiting magnitude of g = 19.91 AB mag and\nz=18.20 AB mag at 5{\\sigma} with 180 sec exposure time for point source\ndetection.\n",
"title": "Seoul National University Camera II (SNUCAM-II): The New SED Camera for the Lee Sang Gak Telescope (LSGT)"
} | null | null | null | null | true | null | 18534 | null | Default | null | null |
null | {
"abstract": " We consider a class of a nested optimization problems involving inner and\nouter objectives. We observe that by taking into explicit account the\noptimization dynamics for the inner objective it is possible to derive a\ngeneral framework that unifies gradient-based hyperparameter optimization and\nmeta-learning (or learning-to-learn). Depending on the specific setting, the\nvariables of the outer objective take either the meaning of hyperparameters in\na supervised learning problem or parameters of a meta-learner. We show that\nsome recently proposed methods in the latter setting can be instantiated in our\nframework and tackled with the same gradient-based algorithms. Finally, we\ndiscuss possible design patterns for learning-to-learn and present encouraging\npreliminary experiments for few-shot learning.\n",
"title": "A Bridge Between Hyperparameter Optimization and Larning-to-learn"
} | null | null | null | null | true | null | 18535 | null | Default | null | null |
null | {
"abstract": " Designing a new drug is a lengthy and expensive process. As the space of\npotential molecules is very large (10^23-10^60), a common technique during drug\ndiscovery is to start from a molecule which already has some of the desired\nproperties. An interdisciplinary team of scientists generates hypothesis about\nthe required changes to the prototype. In this work, we develop an algorithmic\nunsupervised-approach that automatically generates potential drug molecules\ngiven a prototype drug. We show that the molecules generated by the system are\nvalid molecules and significantly different from the prototype drug. Out of the\ncompounds generated by the system, we identified 35 FDA-approved drugs. As an\nexample, our system generated Isoniazid - one of the main drugs for\nTuberculosis. The system is currently being deployed for use in collaboration\nwith pharmaceutical companies to further analyze the additional generated\nmolecules.\n",
"title": "Accelerating Prototype-Based Drug Discovery using Conditional Diversity Networks"
} | null | null | null | null | true | null | 18536 | null | Default | null | null |
null | {
"abstract": " This paper deals with feature selection procedures for spatial point\nprocesses intensity estimation. We consider regularized versions of estimating\nequations based on Campbell theorem derived from two classical functions:\nPoisson likelihood and logistic regression likelihood. We provide general\nconditions on the spatial point processes and on penalty functions which ensure\nconsistency, sparsity and asymptotic normality. We discuss the numerical\nimplementation and assess finite sample properties in a simulation study.\nFinally, an application to tropical forestry datasets illustrates the use of\nthe proposed methods.\n",
"title": "Convex and non-convex regularization methods for spatial point processes intensity estimation"
} | null | null | [
"Mathematics",
"Statistics"
]
| null | true | null | 18537 | null | Validated | null | null |
null | {
"abstract": " The origins of rapid dynamical slow down in glass forming liquids in the\ngrowth of static length scales, possibly associated with identifiable\nstructural ordering, is a much debated issue. Growth of medium range\ncrystalline order (MRCO) has been observed in various model systems to be\nassociated with glassy behaviour. Such observations raise the question about\nthe eventual state reached by a glass former, if allowed to relax for\nsufficiently long times. Is a slowly growing crystalline order responsible for\nslow dynamics? Are the molecular mechanisms for glass transition in liquids\nwith and without MRCO the same? If yes, glass formers with MRCO provide a\nparadigm for understanding glassy behaviour generically. If not, systems with\nMRCO form a new class of glass forming materials whose molecular mechanism for\nslow dynamics may be easier to understand in terms of growing crystalline\norder, and should be approached in that manner, even while they will not\nprovide generic insights. In this study we perform extensive molecular dynamics\nsimulations of a number of glass forming liquids in two dimensions and show\nthat the static and dynamic properties of glasses with MRCO are different from\nother glass forming liquids with no predominant local order. We also resolve an\nimportant issue regarding the so-called Point-to-set method for determining\nstatic length scales, and demonstrate it to be a robust, order agnostic, method\nfor determining static correlation lengths in glass formers.\n",
"title": "Glass Transition in Supercooled Liquids with Medium Range Crystalline Order"
} | null | null | [
"Physics"
]
| null | true | null | 18538 | null | Validated | null | null |
null | {
"abstract": " Technological civilizations may rely upon large-scale photovoltaic arrays to\nharness energy from their host star. Photovoltaic materials, such as silicon,\npossess distinctive spectral features, including an \"artificial edge\" that is\ncharacteristically shifted in wavelength shortwards of the \"red edge\" of\nvegetation. Future observations of reflected light from exoplanets would be\nable to detect both natural and artificial edges photometrically, if a\nsignificant fraction of the planet's surface is covered by vegetation or\nphotovoltaic arrays respectively. The stellar energy thus tapped can be\nutilized for terraforming activities by transferring heat and light from the\nday side to the night side on tidally locked exoplanets, thereby producing\ndetectable artifacts.\n",
"title": "Natural and Artificial Spectral Edges in Exoplanets"
} | null | null | null | null | true | null | 18539 | null | Default | null | null |
null | {
"abstract": " This paper addressed the issue of estimating the damage caused by a computer\nvirus. First, an individual-level delayed SIR model capturing the spreading\nprocess of a digital virus is derived. Second, the damage inflicted by the\nvirus is modeled as the sum of the economic losses and the cost for developing\nthe antivirus. Next, the impact of different factors, including the delay and\nthe network structure, on the damage is explored by means of computer\nsimulations. Thereby some measures of reducing the damage of a virus are\nrecommended. To our knowledge, this is the first time the antivirus-developing\ncost is taken into account when estimating the damage of a virus.\n",
"title": "The damage inflicted by a computer virus: A new estimation method"
} | null | null | null | null | true | null | 18540 | null | Default | null | null |
null | {
"abstract": " Non-availability of reliable and sustainable electric power is a major\nproblem in the developing world. Renewable energy sources like solar are not\nvery lucrative in the current stage due to various uncertainties like weather,\nstorage, land use among others. There also exists various other issues like\nmis-commitment of power, absence of intelligent fault analysis, congestion,\netc. In this paper, we propose a novel deep learning-based system for\npredicting faults and selecting power generators optimally so as to reduce\ncosts and ensure higher reliability in solar power systems. The results are\nhighly encouraging and they suggest that the approaches proposed in this paper\nhave the potential to be applied successfully in the developing world.\n",
"title": "Deep Fault Analysis and Subset Selection in Solar Power Grids"
} | null | null | null | null | true | null | 18541 | null | Default | null | null |
null | {
"abstract": " We express the coefficients of the Hirzebruch L-polynomials in terms of\ncertain alternating multiple zeta values. In particular, we show that every\nmonomial in the Pontryagin classes appears with a non-zero coefficient, with\nthe expected sign. Similar results hold for the polynomials associated to the\nA-hat genus.\n",
"title": "Hirzebruch L-polynomials and multiple zeta values"
} | null | null | null | null | true | null | 18542 | null | Default | null | null |
null | {
"abstract": " Let {\\Xi} be a function relating to the Riemann zeta function with . In this\npaper, we construct a function containing and {\\Xi} , and prove that satisfies\na nonadjoint boundary value problem to a nonsingular differential equation if\nis any nontrivial zero of {\\Xi} . Inspecting properties of and using known\nresults of nontrivial zeros of , we derive that nontrivial zeros of all have\nreal part equal to , which concludes that Riemann Hypothesis is true.\n",
"title": "On Nontrivial Zeros of Riemann Zeta Function"
} | null | null | null | null | true | null | 18543 | null | Default | null | null |
null | {
"abstract": " Background: Many researchers have studied the relationship between diet and\nhealth. There are papers showing an association between the consumption of\nsugar-sweetened beverages and Type 2 diabetes. Many meta-analyses use\nindividual studies that do not adjust for multiple testing or multiple modeling\nand thus provide biased estimates of effect. Hence the claims reported in a\nmeta-analysis paper may be unreliable if the primary papers do not ensure\nunbiased estimates of effect. Objective: Determine the statistical reliability\nof 10 papers and indirectly the reliability of the meta-analysis study. Method:\nTen primary papers used in a meta-analysis paper and counted the numbers of\noutcomes, predictors, and covariates. We estimated the size of the potential\nanalysis search space available to the authors of these papers; i.e. the number\nof comparisons and models available. Since we noticed that there were\ndifferences between predictors and covariates cited in the abstract and in the\ntext, we applied this formula to information found in the abstracts, Space A,\nas well as the text, Space T, of each primary paper. Results: The median and\nrange of the number of comparisons possible across the primary papers are 6.5\nand (2-12,288) for abstracts, and 196,608 and (3,072-117,117,952) the texts.\nNote that the median of 6.5 for Space A is misleading as each primary study has\n60-165 foods not mentioned in the abstract. Conclusion: Given that testing is\nat the 0.05 level and the number of comparisons is very large, nominal\nstatistical significance is very weak support for a claim. The claims in these\npapers are not statistically supported and hence are unreliable. Thus, the\nclaims of the meta-analysis paper lack evidentiary confirmation.\n",
"title": "The reliability of a nutritional meta-analysis study"
} | null | null | null | null | true | null | 18544 | null | Default | null | null |
null | {
"abstract": " We achieve an explicit construction of the lowest Landau level (LLL)\nprojected wave functions for composite fermions in the periodic (torus)\ngeometry. To this end, we first demonstrate how the vortex attachment of the\ncomposite fermion (CF) theory can be accomplished in the torus geometry to\nproduce the \"unprojected\" wave functions satisfying the correct\n(quasi-)periodic boundary conditions. We then consider two methods for\nprojecting these wave functions into the LLL. The direct projection produces\nvalid wave functions but can be implemented only for very small systems. The\nmore powerful and more useful projection method of Jain and Kamilla fails in\nthe torus geometry because it does not preserve the periodic boundary\nconditions and thus takes us out of the original Hilbert space. We have\nsucceeded in constructing a modified projection method that is consistent with\nboth the periodic boundary conditions and the general structure of the CF\ntheory. This method is valid for a large class of states of composite fermions,\ncalled \"proper states,\" which includes the incompressible ground states at\nelectron filling factors $\\nu=\\frac{n}{2pn+ 1}$, their charged and neutral\nexcitations, and also the quasidegenerate ground states at arbitrary filling\nfactors of the form $\\nu=\\frac{\\nu^*}{2p\\nu^*+ 1}$, where $n$ and $p$ are\nintegers and $\\nu^*$ is the CF filling factor. Comparison with exact results\nknown for small systems for the ground and excited states at filling factors\n$\\nu=1/3$, 2/5 and 3/7 demonstrates our LLL-projected wave functions to be\nextremely accurate representations of the actual Coulomb eigenstates. Our\nconstruction enables the study of large systems of composite fermions on the\ntorus, thereby opening the possibility of investigating numerous interesting\nquestions and phenomena.\n",
"title": "Composite Fermions on a Torus"
} | null | null | null | null | true | null | 18545 | null | Default | null | null |
null | {
"abstract": " The Linked Data principles provide a decentral approach for publishing\nstructured data in the RDF format on the Web. In contrast to structured data\npublished in relational databases where a key is often provided explicitly,\nfinding a set of properties that allows identifying a resource uniquely is a\nnon-trivial task. Still, finding keys is of central importance for manifold\napplications such as resource deduplication, link discovery, logical data\ncompression and data integration. In this paper, we address this research gap\nby specifying a refinement operator, dubbed ROCKER, which we prove to be\nfinite, proper and non-redundant. We combine the theoretical characteristics of\nthis operator with two monotonicities of keys to obtain a time-efficient\napproach for detecting keys, i.e., sets of properties that describe resources\nuniquely. We then utilize a hash index to compute the discriminability score\nefficiently. Therewith, we ensure that our approach can scale to very large\nknowledge bases. Results show that ROCKER yields more accurate results, has a\ncomparable runtime, and consumes less memory w.r.t. existing state-of-the-art\ntechniques.\n",
"title": "ROCKER: A Refinement Operator for Key Discovery"
} | null | null | null | null | true | null | 18546 | null | Default | null | null |
null | {
"abstract": " I apply the recently developed formalism of generalized quasiclassical theory\nto show that using hybrid superconducting systems with non-collinear strong\nferromagnets one can realize the Josephson junction between Berezinskii-type\nsuperconductors. The reported calculation reproduces main features observed in\nthe recent experiment, namely the the slightly asymmetric double-slit\nFraunhofer interference pattern of the Josephson current through the\nferromagnetic vortex. The double-slit structure results from the spatially\ninhomogeneous Berezinskii state with the amplitude controlled by the local\nangle between magnetic moments in two ferromagnetic layers. The critical\ncurrent asymmetry by the sign of magnetic field can signal the presence of\nspontaneous supercurrents generated by the non-coplanar magnetic texture near\nthe core of the ferromagnetic vortex core. I demonstrate that ferromagnetic\nvortex can induce spontaneous vorticity in the odd-frequency order parameter\nmanifesting the possibility of the emergent magnetic field to create\ntopological defects.\n",
"title": "Double-slit Fraunhofer pattern as the signature of the Josephson effect between Berezinskii superconductors through the ferromagnetic vortex"
} | null | null | [
"Physics"
]
| null | true | null | 18547 | null | Validated | null | null |
null | {
"abstract": " We study a multi-parametric family of quadratic algebras in four generators,\nwhich includes coordinate algebras of noncommutative four-planes and, as\nquotient algebras, noncommutative three spheres. Particular subfamilies\ncomprise Sklyanin algebras and Connes--Dubois-Violette planes. We determine\nquantum groups of symmetries for the general algebras and construct\nfinite-dimensional covariant differential calculi.\n",
"title": "A class of differential quadratic algebras and their symmetries"
} | null | null | [
"Mathematics"
]
| null | true | null | 18548 | null | Validated | null | null |
null | {
"abstract": " These are notes from introductory lectures at the graduate school\n\"Topological Quantum Groups\" in Będlewo (June 28--July 11, 2015). The notes\npresent the passage from Hopf algebras to compact quantum groups and sketch the\nnotion of discrete quantum groups viewed as duals of compact quantum groups.\n",
"title": "Introduction to compact and discrete quantum groups"
} | null | null | [
"Mathematics"
]
| null | true | null | 18549 | null | Validated | null | null |
null | {
"abstract": " Firms should keep capital to offer sufficient protection against the risks\nthey are facing. In the insurance context methods have been developed to\ndetermine the minimum capital level required, but less so in the context of\nfirms with multiple business lines including allocation. The individual capital\nreserve of each line can be represented by means of classical models, such as\nthe conventional Cramér-Lundberg model, but the challenge lies in soundly\nmodelling the correlations between the business lines. We propose a simple yet\nversatile approach that allows for dependence by introducing a common\nenvironmental factor. We present a novel Bayesian approach to calibrate the\nlatent environmental state distribution based on observations concerning the\nclaim processes. The calibration approach is adjusted for an environmental\nfactor that changes over time. The convergence of the calibration procedure\ntowards the true environmental state is deduced. We then point out how to\ndetermine the optimal initial capital of the different business lines under\nspecific constraints on the ruin probability of subsets of business lines. Upon\ncombining the above findings, we have developed an easy-to-implement approach\nto capital risk management in a multi-dimensional insurance risk model.\n",
"title": "An optimization approach to adaptive multi-dimensional capital management"
} | null | null | [
"Quantitative Finance"
]
| null | true | null | 18550 | null | Validated | null | null |
null | {
"abstract": " Angle-resolved photoemission (ARPES) experiments on copper oxide\nsuperconductors revealed enigmatic kinks in electronic dispersions near 10 meV\npresumably due to phonons or impuritites. We used inelastic neutron scattering\nto measure phonon branches below 15 meV in a large single crystal sample of\noptimally-doped $Bi_2Sr_2CaCu_2O_{8+\\delta}$ (BSCCO). The high quality dataset\ncovered several Brilloiun zones with different final energies. In addition to\nacoustic branches, optic branches disperse from 4 meV and 7 meV zone center\nenergies. The 4 meV branch interacts with acoustic phonons at small\nwavevectors, which destroys the LA character of the acoustic branch beyond\n~0.15 reciprocal lattice units. We propose a mechanism that explains the low\nenergy electronic dispersion features based on this observation.\n",
"title": "Low Energy Phonons in $Bi_2Sr_2CaCu_2O_{8+δ}$ and their Possible Interaction with Electrons Measured by Inelastic Neutron Scattering"
} | null | null | null | null | true | null | 18551 | null | Default | null | null |
null | {
"abstract": " We prove the theorem on the completeness of the root functions of the\nSchroedinger operator $L=-d^2/dx^2+p(x)$ on the semi-axis $\\mathbb R_+$ with a\ncomplex--valued potential $p(x)$. It is assumed that the potential $p = q \\pm\nir$ is such that the real functions $q$ and $r$ are subject the conditions $$\nq(x) \\geqslant c r(x), \\quad r(x) \\geqslant c_0+ c_1 x^\\alpha, \\quad \\alpha >0,\n$$ where the constants $c, \\ c_0\\in \\mathbb R$, $c_1>0$ and $\\arg(\\pm i+c) <\n2\\alpha\\pi/(2+\\alpha)$. For the case of the Airy operator $L_c=-d^2/dx^2+cx$,\n$c=const$, this theorem imply the completeness of the system of the\neigenfunctions of this operator if $|\\arg c|<2\\pi/3$. Using another technique\nbased on the asymptotic behavior of the Airy functions we prove that the\ncompleteness theorem for the operator $L_c$ remains valid, provided that $|\\arg\nc|<5\\pi/6$.\n",
"title": "Spectral properties of complex Airy operator on the semi-axis"
} | null | null | null | null | true | null | 18552 | null | Default | null | null |
null | {
"abstract": " We define web categories describing intertwiners for the orthogonal and\nsymplectic Lie algebras, and, in the quantized setup, for certain orthogonal\nand symplectic coideal subalgebras. They generalize the Brauer category, and\nallow us to prove quantum versions of some classical type\n$\\mathbf{B}\\mathbf{C}\\mathbf{D}$ Howe dualities.\n",
"title": "Webs and $q$-Howe dualities in types $\\mathbf{B}\\mathbf{C}\\mathbf{D}$"
} | null | null | [
"Mathematics"
]
| null | true | null | 18553 | null | Validated | null | null |
null | {
"abstract": " One version of the concept of structural controllability defined for\nsingle-input systems by Lin and subsequently generalized to multi-input systems\nby others, states that a parameterized matrix pair $(A, B)$ whose nonzero\nentries are distinct parameters, is structurally controllable if values can be\nassigned to the parameters which cause the resulting matrix pair to be\ncontrollable. In this paper the concept of structural controllability is\nbroadened to allow for the possibility that a parameter may appear in more than\none location in the pair $(A, B)$. Subject to a certain condition on the\nparameterization called the \"binary assumption\", an explicit graph-theoretic\ncharacterization of such matrix pairs is derived.\n",
"title": "Structural Controllability of Linear Time-invariant Systems"
} | null | null | null | null | true | null | 18554 | null | Default | null | null |
null | {
"abstract": " We study the structure of martingale transports in finite dimensions. We\nconsider the family $\\mathcal{M}(\\mu,\\nu) $ of martingale measures on\n$\\mathbb{R}^N \\times \\mathbb{R}^N$ with given marginals $\\mu,\\nu$, and\nconstruct a family of relatively open convex sets $\\{C_x:x\\in \\mathbb{R}^N \\}$,\nwhich forms a partition of $\\mathbb{R}^N$, and such that any martingale\ntransport in $\\mathcal{M}(\\mu,\\nu) $ sends mass from $x$ to within\n$\\overline{C_x}$, $\\mu(dx)$--a.e. Our results extend the analogous\none-dimensional results of M. Beiglböck and N. Juillet (2016) and M.\nBeiglböck, M. Nutz, and N. Touzi (2015). We conjecture that the decomposition\nis canonical and minimal in the sense that it allows to characterise the\nmartingale polar sets, i.e. the sets which have zero mass under all measures in\n$\\mathcal{M}(\\mu,\\nu)$, and offers the martingale analogue of the\ncharacterisation of transport polar sets proved in M. Beiglböck, M.\nGoldstern, G. Maresch, and W. Schachermayer (2009).\n",
"title": "Structure of martingale transports in finite dimensions"
} | null | null | null | null | true | null | 18555 | null | Default | null | null |
null | {
"abstract": " A branched covering surface-knot is a surface-knot in the form of a branched\ncovering over an oriented surface-knot $F$, where we include the case when the\ncovering has no branch points. A branched covering surface-knot is presented by\na graph called a chart on a surface diagram of $F$. We can simplify a branched\ncovering surface-knot by an addition of 1-handles with chart loops to a form\nsuch that its chart is the union of free edges and 1-handles with chart loops.\nWe investigate properties of such simplifications for the case when branched\ncovering surface-knots have a non-zero number of branch points, using chart\nmoves involving black vertices.\n",
"title": "Simplifying branched covering surface-knots by chart moves involving black vertices"
} | null | null | null | null | true | null | 18556 | null | Default | null | null |
null | {
"abstract": " A well-known question in classical differential geometry and geometric\nanalysis asks for a description of possible boundaries of $K$-surfaces, which\nare smooth, compact hypersurfaces in $\\mathbb{R}^d$ having constant Gauss\ncurvature equal to $K \\geq 0$. This question generated a considerable amount of\nremarkable results in the last few decades. Motivated by these developments\nhere we study the question of determining a $K$-surface when only part of its\nboundary is fixed, and in addition the surface hits a given manifold at some\nfixed angle. While this general setting is out of reach for us at the present,\nwe settle a model case of the problem, which in its analytic formulation\nreduces to a Bernoulli type free boundary problem for the Monge-Ampère\nequation. We study both the cases of 0-curvature and of positive curvature. The\nformulation of the free boundary condition and its regularity are the most\ndelicate and challenging questions addressed in this work. In this regard we\nintroduce a notion of a Blaschke extension of a solution which might be of\nindependent interest.\nThe problem we study can also be interpreted as the Alt-Caffarelli problem\nfor the Monge-Ampère equation. Moreover, it also relates to the problem of\nisometric embedding of a positive metric on the annulus with partially\nprescribed boundary and optimal transport with free mass.\n",
"title": "$K$-surfaces with free boundaries"
} | null | null | null | null | true | null | 18557 | null | Default | null | null |
null | {
"abstract": " We attach to each $\\langle 0, \\vee \\rangle$-semilattice a graph\n$\\boldsymbol{G}_{\\boldsymbol{S}}$ whose vertices are join-irreducible elements\nof $\\boldsymbol{S}$ and whose edges correspond to the reflexive dependency\nrelation. We study properties of the graph $\\boldsymbol{G}_{\\boldsymbol{S}}$\nboth when $\\boldsymbol{S}$ is a join-semilattice and when it is a lattice. We\ncall a $\\langle 0, \\vee \\rangle$-semilattice $\\boldsymbol{S}$ particle provided\nthat the set of its join-irreducible elements join-generates $\\boldsymbol{S}$\nand it satisfies DCC. We prove that the congruence lattice of a particle\nlattice is anti-isomorphic to the lattice of hereditary subsets of the\ncorresponding graph that are closed in a certain zero-dimensional topology.\nThus we extend the result known for principally chain finite lattices.\n",
"title": "The graphs of join-semilattices and the shape of congruence lattices of particle lattices"
} | null | null | null | null | true | null | 18558 | null | Default | null | null |
null | {
"abstract": " A quasi-Gray code of dimension $n$ and length $\\ell$ over an alphabet\n$\\Sigma$ is a sequence of distinct words $w_1,w_2,\\dots,w_\\ell$ from $\\Sigma^n$\nsuch that any two consecutive words differ in at most $c$ coordinates, for some\nfixed constant $c>0$. In this paper we are interested in the read and write\ncomplexity of quasi-Gray codes in the bit-probe model, where we measure the\nnumber of symbols read and written in order to transform any word $w_i$ into\nits successor $w_{i+1}$.\nWe present construction of quasi-Gray codes of dimension $n$ and length $3^n$\nover the ternary alphabet $\\{0,1,2\\}$ with worst-case read complexity $O(\\log\nn)$ and write complexity $2$. This generalizes to arbitrary odd-size alphabets.\nFor the binary alphabet, we present quasi-Gray codes of dimension $n$ and\nlength at least $2^n - 20n$ with worst-case read complexity $6+\\log n$ and\nwrite complexity $2$. This complements a recent result by Raskin [Raskin '17]\nwho shows that any quasi-Gray code over binary alphabet of length $2^n$ has\nread complexity $\\Omega(n)$.\nOur results significantly improve on previously known constructions and for\nthe odd-size alphabets we break the $\\Omega(n)$ worst-case barrier for\nspace-optimal (non-redundant) quasi-Gray codes with constant number of writes.\nWe obtain our results via a novel application of algebraic tools together with\nthe principles of catalytic computation [Buhrman et al. '14, Ben-Or and Cleve\n'92, Barrington '89, Coppersmith and Grossman '75].\n",
"title": "Optimal Quasi-Gray Codes: The Alphabet Matters"
} | null | null | null | null | true | null | 18559 | null | Default | null | null |
null | {
"abstract": " Recent theoretical work has shown that the pre-main-sequence (PMS) evolution\nof stars is much more complex than previously envisioned. Instead of the\ntraditional steady, one-dimensional solution, accretion may be episodic and not\nnecessarily symmetrical, thereby affecting the energy deposited inside the star\nand its interior structure. Given this new framework, we want to understand\nwhat controls the evolution of accreting stars. We use the MESA stellar\nevolution code with various sets of conditions. In particular, we account for\nthe (unknown) efficiency of accretion in burying gravitational energy into the\nprotostar through a parameter, $\\xi$, and we vary the amount of deuterium\npresent. We confirm the findings of previous works that the evolution changes\nsignificantly with the amount of energy that is lost during accretion. We find\nthat deuterium burning also regulates the PMS evolution. In the low-entropy\naccretion scenario, the evolutionary tracks in the H-R diagram are\nsignificantly different from the classical tracks and are sensitive to the\ndeuterium content. A comparison of theoretical evolutionary tracks and\nobservations allows us to exclude some cold accretion models ($\\xi\\sim 0$) with\nlow deuterium abundances. We confirm that the luminosity spread seen in\nclusters can be explained by models with a somewhat inefficient injection of\naccretion heat. The resulting evolutionary tracks then become sensitive to the\naccretion heat efficiency, initial core entropy, and deuterium content. In this\ncontext, we predict that clusters with a higher D/H ratio should have less\nscatter in luminosity than clusters with a smaller D/H. Future work on this\nissue should include radiation-hydrodynamic simulations to determine the\nefficiency of accretion heating and further observations to investigate the\ndeuterium content in star-forming regions. (abbrev.)\n",
"title": "Revisiting the pre-main-sequence evolution of stars I. Importance of accretion efficiency and deuterium abundance"
} | null | null | null | null | true | null | 18560 | null | Default | null | null |
null | {
"abstract": " We present a quantum-mechanical model for surface-assisted carrier excitation\nby optical fields in plasmonic nanostructures of arbitrary shape. We derive an\nexplicit expression, in terms of local fields inside the metal structure, for\nsurface absorbed power and surface scattering rate that determine the\nenhancement of carrier excitation efficiency near the metal-dielectric\ninterface. We show that surface scattering is highly sensitive to the local\nfield polarization, and can be incorporated into metal dielectric function\nalong with phonon and impurity scattering. We also show that the obtained\nsurface scattering rate describes surface-assisted plasmon decay (Landau\ndamping) in nanostructures larger than the nonlocality scale. Our model can be\nused for calculations of plasmon-assisted hot carrier generation rates in\nphotovoltaics and photochemistry applications.\n",
"title": "Surface-assisted carrier excitation in plasmonic nanostructure"
} | null | null | null | null | true | null | 18561 | null | Default | null | null |
null | {
"abstract": " We explore the existence of global weak solutions to the Hookean dumbbell\nmodel, a system of nonlinear partial differential equations that arises from\nthe kinetic theory of dilute polymers, involving the unsteady incompressible\nNavier--Stokes equations in a bounded domain in two or three space dimensions,\ncoupled to a Fokker--Planck-type parabolic equation. We prove the existence of\nlarge-data global weak solutions in the case of two space dimensions.\nIndirectly, our proof also rigorously demonstrates that, in two space\ndimensions at least, the Oldroyd-B model is the macroscopic closure of the\nHookean dumbbell model. In three space dimensions, we prove the existence of\nlarge-data global weak subsolutions to the model, which are weak solutions with\na defect measure, where the defect measure appearing in the Navier--Stokes\nmomentum equation is the divergence of a symmetric positive semidefinite\nmatrix-valued Radon measure.\n",
"title": "Existence of global weak solutions to the kinetic Hookean dumbbell model for incompressible dilute polymeric fluids"
} | null | null | null | null | true | null | 18562 | null | Default | null | null |
null | {
"abstract": " We resolve a number of long-standing open problems in online graph coloring.\nMore specifically, we develop tight lower bounds on the performance of online\nalgorithms for fundamental graph classes. An important contribution is that our\nbounds also hold for randomized online algorithms, for which hardly any results\nwere known. Technically, we construct lower bounds for chordal graphs. The\nconstructions then allow us to derive results on the performance of randomized\nonline algorithms for the following further graph classes: trees, planar,\nbipartite, inductive, bounded-treewidth and disk graphs. It shows that the best\ncompetitive ratio of both deterministic and randomized online algorithms is\n$\\Theta(\\log n)$, where $n$ is the number of vertices of a graph. Furthermore,\nwe prove that this guarantee cannot be improved if an online algorithm has a\nlookahead of size $O(n/\\log n)$ or access to a reordering buffer of size\n$n^{1-\\epsilon}$, for any $0<\\epsilon\\leq 1$. A consequence of our results is\nthat, for all of the above mentioned graph classes except bipartite graphs, the\nnatural $\\textit{First Fit}$ coloring algorithm achieves an optimal\nperformance, up to constant factors, among deterministic and randomized online\nalgorithms.\n",
"title": "Tight Bounds for Online Coloring of Basic Graph Classes"
} | null | null | null | null | true | null | 18563 | null | Default | null | null |
null | {
"abstract": " We performed an empirical comparison of ICA and PCA algorithms by applying\nthem on two simulated noisy time series with varying distribution parameters\nand level of noise. In general, ICA shows better results than PCA because it\ntakes into account higher moments of data distribution. On the other hand, PCA\nremains quite sensitive to the level of correlations among signals.\n",
"title": "Comparison of PCA with ICA from data distribution perspective"
} | null | null | null | null | true | null | 18564 | null | Default | null | null |
null | {
"abstract": " The band structure of a Si inverse diamond structure whose lattice point\nshape was vacant regular octahedrons was calculated using plane wave expansion\nmethod and a complete photonic band gap was theoretically confirmed at around\n0.4 THz. It is said that three-dimensional photonic crystals have no\npolarization anisotropy in photonic band gap (stop gap, stop band) of high\nsymmetry points in normal incidence. However, it was experimentally confirmed\nthat the polarization orientation of a reflected light was different from that\nof a incident light, {I(X,Y)}, where (X,Y) is the coordinate system fixed in\nthe photonic crystal. It was studied on a plane (001) at around X point's\nphotonic band gap (0.36 - 0.44 THz) for incident light direction [001]\n($\\Gamma$-X direction) by rotating a sample in the plane (001), relatively. The\npolarization orientation of the reflected light was parallel to that of the\nincident light for the incident polarization orientation I(1,1), I(1,-1). In\ncontrast, the former was perpendicular to the latter for the incident\npolarization orientation I(1,0), I(0,-1) in the vicinity of 0.38 THz. As far as\nthe photonic crystal in this work is concerned, method of resolution and\nsynthesis of the incident polarization vector isn't apparently able to apply to\nthe analysis of experimental results.\n",
"title": "The Special Polarization Characteristic Features of a Three-Dimensional Terahertz Photonic Crystal with a Silicon Inverse Diamond Structure"
} | null | null | null | null | true | null | 18565 | null | Default | null | null |
null | {
"abstract": " In the last decade, digital footprints have been used to cluster population\nactivity into functional areas of cities.\nHowever, a key aspect has been overlooked: we experience our cities not only\nby performing activities at specific destinations, but also by moving from one\nplace to another.\nIn this paper, we propose to analyze and cluster the city based on how people\nmove through it. Particularly, we introduce Mobilicities, automatically\ngenerated travel patterns inferred from mobile phone network data using NMF, a\nmatrix factorization model.\nWe evaluate our method in a large city and we find that mobilicities reveal\nlatent but at the same time interpretable mobility structures of the city. Our\nresults provide evidence on how clustering and visualization of aggregated\nphone logs could be used in planning systems to interactively analyze city\nstructure and population activity.\n",
"title": "Toward Finding Latent Cities with Non-Negative Matrix Factorization"
} | null | null | null | null | true | null | 18566 | null | Default | null | null |
null | {
"abstract": " We argue that Time-Sensitive Networking (TSN) will become the de facto\nstandard for real-time communications in robotics. We present a review and\nclassification of the different communication standards which are relevant for\nthe field and introduce the typical problems with traditional switched Ethernet\nnetworks. We discuss some of the TSN features relevant for deterministic\ncommunications and evaluate experimentally one of the shaping mechanisms in an\nexemplary robotic scenario. In particular, and based on our results, we claim\nthat many of the existing real-time industrial solutions will slowly be\nreplaced by TSN. And that this will lead towards a unified landscape of\nphysically interoperable robot and robot components.\n",
"title": "Time-Sensitive Networking for robotics"
} | null | null | null | null | true | null | 18567 | null | Default | null | null |
null | {
"abstract": " Sparse Subspace Clustering (SSC) is a state-of-the-art method for clustering\nhigh-dimensional data points lying in a union of low-dimensional subspaces.\nHowever, while $\\ell_1$ optimization-based SSC algorithms suffer from high\ncomputational complexity, other variants of SSC, such as Orthogonal Matching\nPursuit-based SSC (OMP-SSC), lose clustering accuracy in pursuit of improving\ntime efficiency. In this letter, we propose a novel Active OMP-SSC, which\nimproves clustering accuracy of OMP-SSC by adaptively updating data points and\nrandomly dropping data points in the OMP process, while still enjoying the low\ncomputational complexity of greedy pursuit algorithms. We provide heuristic\nanalysis of our approach, and explain how these two active steps achieve a\nbetter tradeoff between connectivity and separation. Numerical results on both\nsynthetic data and real-world data validate our analyses and show the\nadvantages of the proposed active algorithm.\n",
"title": "Active Orthogonal Matching Pursuit for Sparse Subspace Clustering"
} | null | null | null | null | true | null | 18568 | null | Default | null | null |
null | {
"abstract": " Measurements of AC losses in a HTS-tape placed in between of two bulk\nmagnetic shields of high permeability were performed by applying calorimetric\ntechniques for various asymmetrical shielding arrangements. The experiment was\nsupported by analytical calculations and finite-element simulations of the\nfield and current distributions, based on the Bean model of the critical state.\nThe simulated current and field profiles perfectly reproduce the analytic\nsolutions known for certain shielding geometries. The evaluation of the\nconsequent AC losses exhibits good agreement with measurements for the central\nposition of the tape between the magnets but increasing discrepancy when the\ntape is approaching the shields. This can be explained by the increasing\ncontribution of the eddy currents and magnetic hysteresis losses in the\nconducting shields.\n",
"title": "Experimental and theoretical study of AC losses in variable asymmetrical magnetic environments"
} | null | null | null | null | true | null | 18569 | null | Default | null | null |
null | {
"abstract": " We examine the performance of efficient and AIPW estimators under two-phase\nsampling when the complete-data model is nearly correctly specified, in the\nsense that the misspecification is not reliably detectable from the data by any\npossible diagnostic or test. Asymptotic results for these nearly true models\nare obtained by representing them as sequences of misspecified models that are\nmutually contiguous with a correctly specified model. We find that for the\nleast-favourable direction of model misspecification the bias in the efficient\nestimator induced can be comparable to the extra variability in the AIPW\nestimator, so that the mean squared error of the efficient estimator is no\nlonger lower. This can happen when the most-powerful test for the model\nmisspecification still has modest power. We verify that the theoretical results\nagree with simulation in three examples: a simple informative-sampling model\nfor a Normal mean, logistic regression in the classical case-control design,\nand linear regression in a two-phase design.\n",
"title": "Robustness of semiparametric efficiency in nearly-true models for two-phase samples"
} | null | null | null | null | true | null | 18570 | null | Default | null | null |
null | {
"abstract": " We propose a new A* CCG parsing model in which the probability of a tree is\ndecomposed into factors of CCG categories and its syntactic dependencies both\ndefined on bi-directional LSTMs. Our factored model allows the precomputation\nof all probabilities and runs very efficiently, while modeling sentence\nstructures explicitly via dependencies. Our model achieves the state-of-the-art\nresults on English and Japanese CCG parsing.\n",
"title": "A* CCG Parsing with a Supertag and Dependency Factored Model"
} | null | null | [
"Computer Science"
]
| null | true | null | 18571 | null | Validated | null | null |
null | {
"abstract": " We have developed polynomial-time algorithms to generate terms of the\ncogrowth series for groups $\\mathbb{Z}\\wr \\mathbb{Z},$ the lamplighter group,\n$(\\mathbb{Z}\\wr \\mathbb{Z})\\wr \\mathbb{Z}$ and the Navas-Brin group $B.$ We\nhave also given an improved algorithm for the coefficients of Thompson's group\n$F,$ giving 32 terms of the cogrowth series. We develop numerical techniques to\nextract the asymptotics of these various cogrowth series. We present improved\nrigorous lower bounds on the growth-rate of the cogrowth series for Thompson's\ngroup $F$ using the method from \\cite{HHR15} applied to our extended series. We\nalso generalise their method by showing that it applies to loops on any locally\nfinite graph. Unfortunately, lower bounds less than 16 do not help in\ndetermining amenability.\nAgain for Thompson's group $F$ we prove that, if the group is amenable, there\ncannot be a sub-dominant stretched exponential term in the\nasymptotics\\footnote{ }. Yet the numerical data provides compelling evidence\nfor the presence of such a term. This observation suggests a potential path to\na proof of non-amenability: If the universality class of the cogrowth sequence\ncan be determined rigorously, it will likely prove non-amenability.\nWe estimate the asymptotics of the cogrowth coefficients of $F$ to be $$ c_n\n\\sim c \\cdot \\mu^n \\cdot \\kappa^{n^\\sigma \\log^\\delta{n}} \\cdot n^g,$$ where\n$\\mu \\approx 15,$ $\\kappa \\approx 1/e,$ $\\sigma \\approx 1/2,$ $\\delta \\approx\n1/2,$ and $g \\approx -1.$ The growth constant $\\mu$ must be 16 for amenability.\nThese two approaches, plus a third based on extrapolating lower bounds, support\nthe conjecture \\cite{ERvR15, HHR15} that the group is not amenable.\n",
"title": "Numerical studies of Thompson's group F and related groups"
} | null | null | null | null | true | null | 18572 | null | Default | null | null |
null | {
"abstract": " The assumption that action and perception can be investigated independently\nis entrenched in theories, models and experimental approaches across the brain\nand mind sciences. In cognitive science, this has been a central point of\ncontention between computationalist and 4Es (enactive, embodied, extended and\nembedded) theories of cognition, with the former embracing the \"classical\nsandwich\", modular, architecture of the mind and the latter actively denying\nthis separation can be made. In this work we suggest that the modular\nindependence of action and perception strongly resonates with the separation\nprinciple of control theory and furthermore that this principle provides formal\ncriteria within which to evaluate the implications of the modularity of action\nand perception. We will also see that real-time feedback with the environment,\noften considered necessary for the definition of 4Es ideas, is not however a\nsufficient condition to avoid the \"classical sandwich\". Finally, we argue that\nan emerging framework in the cognitive and brain sciences, active inference,\nextends ideas derived from control theory to the study of biological systems\nwhile disposing of the separation principle, describing non-modular models of\nbehaviour strongly aligned with 4Es theories of cognition.\n",
"title": "The modularity of action and perception revisited using control theory and active inference"
} | null | null | null | null | true | null | 18573 | null | Default | null | null |
null | {
"abstract": " In this article, we develop a clique-based method for social network\nclustering. We introduce a new index to evaluate the quality of clustering\nresults, and propose an efficient algorithm based on recursive bipartition to\nmaximize an objective function of the proposed index. The optimization problem\nis NP-hard, so we approximate the semi-optimal solution via an implicitly\nrestarted Lanczos method. One of the advantages of our algorithm is that the\nproposed index of each community in the clustering result is guaranteed to be\nhigher than some predetermined threshold, $p$, which is completely controlled\nby users. We also account for the situation that $p$ is unknown. A statistical\nprocedure of controlling both under-clustering and over-clustering errors\nsimultaneously is carried out to select localized threshold for each\nsubnetwork, such that the community detection accuracy is optimized.\nAccordingly, we propose a localized clustering algorithm based on binary tree\nstructure. Finally, we exploit the stochastic blockmodels to conduct simulation\nstudies and demonstrate the accuracy and efficiency of our algorithms, both\nnumerically and graphically.\n",
"title": "Clique-based Method for Social Network Clustering"
} | null | null | null | null | true | null | 18574 | null | Default | null | null |
null | {
"abstract": " We extend the formalism of Matrix Product States (MPS) to describe\none-dimensional gapped systems of fermions with both unitary and anti-unitary\nsymmetries. Additionally, systems with orientation-reversing spatial symmetries\nare considered. The short-ranged entangled phases of such systems are\nclassified by three invariants, which characterize the projective action of the\nsymmetry on edge states. We give interpretations of these invariants as\nproperties of states on the closed chain. The relationship between fermionic\nMPS systems at an RG fixed point and equivariant algebras is exploited to\nderive a group law for the stacking of fermionic phases. The result generalizes\nknown classifications to symmetry groups that are non-trivial extensions of\nfermion parity and time-reversal.\n",
"title": "Fermionic Matrix Product States and One-Dimensional Short-Range Entangled Phases with Anti-Unitary Symmetries"
} | null | null | null | null | true | null | 18575 | null | Default | null | null |
null | {
"abstract": " On their roller coaster ride through turbulence, tracer particles sample the\nfluctuations of the underlying fields in space and time. Quantitatively\nrelating particle and field statistics remains a fundamental challenge in a\nlarge variety of turbulent flows. We quantify how tracer particles sample\nturbulence by expressing their temporal velocity fluctuations in terms of an\neffective probabilistic sampling of spatial velocity field fluctuations. To\ncorroborate our theory, we investigate an extensive suite of direct numerical\nsimulations of hydrodynamic turbulence covering a Taylor-scale Reynolds number\nrange from 150 to 430. Our approach allows the assessment of particle\nstatistics from the knowledge of flow field statistics only, therefore opening\navenues to a new generation of models for transport in complex flows.\n",
"title": "How tracer particles sample the complexity of turbulence"
} | null | null | null | null | true | null | 18576 | null | Default | null | null |
null | {
"abstract": " We study a static game played by a finite number of agents, in which agents\nare assigned independent and identically distributed random types and each\nagent minimizes its objective function by choosing from a set of admissible\nactions that depends on its type. The game is anonymous in the sense that the\nobjective function of each agent depends on the actions of other agents only\nthrough the empirical distribution of their type-action pairs. We study the\nasymptotic behavior of Nash equilibria, as the number of agents tends to\ninfinity, first by deriving laws of large numbers characterizes almost sure\nlimit points of Nash equilibria in terms of so-called Cournot-Nash equilibria\nof an associated nonatomic game. Our main results are large deviation\nprinciples that characterize the probability of rare Nash equilibria and\nassociated conditional limit theorems describing the behavior of equilibria\nconditioned on a rare event. The results cover situations when neither the\nfinite-player game nor the associated nonatomic game has a unique equilibrium.\nIn addition, we study the asymptotic behavior of the price of anarchy,\ncomplementing existing worst-case bounds with new probabilistic bounds in the\ncontext of congestion games, which are used to model traffic routing in\nnetworks.\n",
"title": "Rare Nash Equilibria and the Price of Anarchy in Large Static Games"
} | null | null | [
"Computer Science",
"Mathematics"
]
| null | true | null | 18577 | null | Validated | null | null |
null | {
"abstract": " We study bivariate stochastic recurrence equations (SREs) motivated by\napplications to GARCH(1,1) processes. If coefficient matrices of SREs have\nstrictly positive entries, then the Kesten result applies and it gives\nsolutions with regularly varying tails. Moreover, the tail indices are the same\nfor all coordinates. However, for applications, this framework is too\nrestrictive. We study SREs when coefficients are triangular matrices and prove\nthat the coordinates of the solution may exhibit regularly varying tails with\ndifferent indices. We also specify each tail index together with its constant.\nThe results are used to characterize regular variations of bivariate stationary\nGARCH(1,1) processes.\n",
"title": "Componentwise different tail solutions for bivariate stochastic recurrence equations -- with application to GARCH(1,1) processes --"
} | null | null | [
"Mathematics",
"Statistics"
]
| null | true | null | 18578 | null | Validated | null | null |
null | {
"abstract": " We present a unified classical treatment of partially constrained elastic\nrods. Partial constraints often entail singularities in both shapes and\nreactions. Our approach encompasses both sleeve and adhesion problems, and\nprovides simple and unambiguous derivations of counterintuitive results in the\nliterature. Relationships between reaction forces and moments, geometry, and\nadhesion energies follow from the balance of energy during quasistatic motion.\nWe also relate our approach to the balance of material momentum and the concept\nof a driving traction. The theory is generalizable and can be applied to a wide\narray of contact, adhesion, gripping, and locomotion problems.\n",
"title": "Partial constraint singularities in elastic rods"
} | null | null | null | null | true | null | 18579 | null | Default | null | null |
null | {
"abstract": " The main goal of modeling human conversation is to create agents which can\ninteract with people in both open-ended and goal-oriented scenarios. End-to-end\ntrained neural dialog systems are an important line of research for such\ngeneralized dialog models as they do not resort to any situation-specific\nhandcrafting of rules. However, incorporating personalization into such systems\nis a largely unexplored topic as there are no existing corpora to facilitate\nsuch work. In this paper, we present a new dataset of goal-oriented dialogs\nwhich are influenced by speaker profiles attached to them. We analyze the\nshortcomings of an existing end-to-end dialog system based on Memory Networks\nand propose modifications to the architecture which enable personalization. We\nalso investigate personalization in dialog as a multi-task learning problem,\nand show that a single model which shares features among various profiles\noutperforms separate models for each profile.\n",
"title": "Personalization in Goal-Oriented Dialog"
} | null | null | [
"Computer Science"
]
| null | true | null | 18580 | null | Validated | null | null |
null | {
"abstract": " Principal Component Analysis (PCA) is a very successful dimensionality\nreduction technique, widely used in predictive modeling. A key factor in its\nwidespread use in this domain is the fact that the projection of a dataset onto\nits first $K$ principal components minimizes the sum of squared errors between\nthe original data and the projected data over all possible rank $K$\nprojections. Thus, PCA provides optimal low-rank representations of data for\nleast-squares linear regression under standard modeling assumptions. On the\nother hand, when the loss function for a prediction problem is not the\nleast-squares error, PCA is typically a heuristic choice of dimensionality\nreduction -- in particular for classification problems under the zero-one loss.\nIn this paper we target classification problems by proposing a straightforward\nalternative to PCA that aims to minimize the difference in margin distribution\nbetween the original and the projected data. Extensive experiments show that\nour simple approach typically outperforms PCA on any particular dataset, in\nterms of classification error, though this difference is not always\nstatistically significant, and despite being a filter method is frequently\ncompetitive with Partial Least Squares (PLS) and Lasso on a wide range of\ndatasets.\n",
"title": "Maximum Margin Principal Components"
} | null | null | null | null | true | null | 18581 | null | Default | null | null |
null | {
"abstract": " In this work a design is proposed for an active, permanent magnet based,\nself-propelled magnetic bearing i.e. levitating motor having the following\nfeatures : (a) simple winding structure, (b) high load supporting capacity, (c)\nno eccentricity sensors, (d) stable confinement in all translational\ndimensions, (e) stable confinement in all rotational dimensions and (f) high\nefficiency. This design uses an architecture consisting of a helically wound\nthree-phase stator, and a rotor with the magnets also arranged in a helical\nmanner. Active control is used to excite the rotor at a torque angle lying in\nthe second quadrant. This torque angle is independent of the rotor's position\ninside the stator cavity hence the control algorithm is similar to that of a\nconventional permanent magnet synchronous motor. It is motivated through a\nphysical argument that the bearing rotor develops a lift force proportional to\nthe output torque and that it remains stably confined in space. These\nassertions are then proved rigorously through a calculation of the magnetic\nfields, forces and torques. The stiffness matrix of the system is presented and\na discussion of stable and unstable operating regions is given.\n",
"title": "A New self-propelled magnetic bearing with helical windings"
} | null | null | null | null | true | null | 18582 | null | Default | null | null |
null | {
"abstract": " How do we learn an object detector that is invariant to occlusions and\ndeformations? Our current solution is to use a data-driven strategy -- collect\nlarge-scale datasets which have object instances under different conditions.\nThe hope is that the final classifier can use these examples to learn\ninvariances. But is it really possible to see all the occlusions in a dataset?\nWe argue that like categories, occlusions and object deformations also follow a\nlong-tail. Some occlusions and deformations are so rare that they hardly\nhappen; yet we want to learn a model invariant to such occurrences. In this\npaper, we propose an alternative solution. We propose to learn an adversarial\nnetwork that generates examples with occlusions and deformations. The goal of\nthe adversary is to generate examples that are difficult for the object\ndetector to classify. In our framework both the original detector and adversary\nare learned in a joint manner. Our experimental results indicate a 2.3% mAP\nboost on VOC07 and a 2.6% mAP boost on VOC2012 object detection challenge\ncompared to the Fast-RCNN pipeline. We also release the code for this paper.\n",
"title": "A-Fast-RCNN: Hard Positive Generation via Adversary for Object Detection"
} | null | null | [
"Computer Science"
]
| null | true | null | 18583 | null | Validated | null | null |
null | {
"abstract": " Linear arrays of trapped and laser cooled atomic ions are a versatile\nplatform for studying emergent phenomena in strongly-interacting many-body\nsystems. Effective spins are encoded in long-lived electronic levels of each\nion and made to interact through laser mediated optical dipole forces. The\nadvantages of experiments with cold trapped ions, including high spatiotemporal\nresolution, decoupling from the external environment, and control over the\nsystem Hamiltonian, are used to measure quantum effects not always accessible\nin natural condensed matter samples. In this review we highlight recent work\nusing trapped ions to explore a variety of non-ergodic phenomena in long-range\ninteracting spin-models which are heralded by memory of out-of-equilibrium\ninitial conditions. We observe long-lived memory in static magnetizations for\nquenched many-body localization and prethermalization, while memory is\npreserved in the periodic oscillations of a driven discrete time crystal state.\n",
"title": "Non-thermalization in trapped atomic ion spin chains"
} | null | null | null | null | true | null | 18584 | null | Default | null | null |
null | {
"abstract": " In this work, we revisit the problem of uniformity testing of discrete\nprobability distributions. A fundamental problem in distribution testing,\ntesting uniformity over a known domain has been addressed over a significant\nline of works, and is by now fully understood.\nThe complexity of deciding whether an unknown distribution is uniform over\nits unknown (and arbitrary) support, however, is much less clear. Yet, this\ntask arises as soon as no prior knowledge on the domain is available, or\nwhenever the samples originate from an unknown and unstructured universe. In\nthis work, we introduce and study this generalized uniformity testing question,\nand establish nearly tight upper and lower bound showing that -- quite\nsurprisingly -- its sample complexity significantly differs from the\nknown-domain case. Moreover, our algorithm is intrinsically adaptive, in\ncontrast to the overwhelming majority of known distribution testing algorithms.\n",
"title": "Generalized Uniformity Testing"
} | null | null | null | null | true | null | 18585 | null | Default | null | null |
null | {
"abstract": " Refraction deflects photons that pass through atmospheres, which affects\ntransit light curves. Refraction thus provides an avenue to probe physical\nproperties of exoplanet atmospheres and to constrain the presence of clouds and\nhazes. In addition, an effective surface can be imposed by refraction, thereby\nlimiting the pressure levels probed by transmission spectroscopy. The main\nobjective of the paper is to model the effects of refraction on photometric\nlight curves for realistic planets and to explore the dependencies on\natmospheric physical parameters. We also explore under which circumstances\ntransmission spectra are significantly affected by refraction. Finally, we\nsearch for refraction signatures in photometric residuals in Kepler data. We\nuse the model of Hui & Seager (2002) to compute deflection angles and\nrefraction transit light curves, allowing us to explore the parameter space of\natmospheric properties. The observational search is performed by stacking large\nsamples of transit light curves from Kepler. We find that out-of-transit\nrefraction shoulders are the most easily observable features, which can reach\npeak amplitudes of ~10 parts per million (ppm) for planets around Sun-like\nstars. More typical amplitudes are a few ppm or less for Jovians and at the\nsub-ppm level for super-Earths. Interestingly, the signal-to-noise ratio of any\nrefraction residuals for planets orbiting Sun-like hosts are expected to be\nsimilar for planets orbiting red dwarfs. We also find that the maximum depth\nprobed by transmission spectroscopy is not limited by refraction for weakly\nlensing planets, but that the incidence of refraction can vary significantly\nfor strongly lensing planets. We find no signs of refraction features in the\nstacked Kepler light curves, which is in agreement with our model predictions.\n",
"title": "Refraction in exoplanet atmospheres: Photometric signatures, implications for transmission spectroscopy, and search in Kepler data"
} | null | null | null | null | true | null | 18586 | null | Default | null | null |
null | {
"abstract": " We describe a multi-phased Wizard-of-Oz approach to collecting human-robot\ndialogue in a collaborative search and navigation task. The data is being used\nto train an initial automated robot dialogue system to support collaborative\nexploration tasks. In the first phase, a wizard freely typed robot utterances\nto human participants. For the second phase, this data was used to design a GUI\nthat includes buttons for the most common communications, and templates for\ncommunications with varying parameters. Comparison of the data gathered in\nthese phases show that the GUI enabled a faster pace of dialogue while still\nmaintaining high coverage of suitable responses, enabling more efficient\ntargeted data collection, and improvements in natural language understanding\nusing GUI-collected data. As a promising first step towards interactive\nlearning, this work shows that our approach enables the collection of useful\ntraining data for navigation-based HRI tasks.\n",
"title": "Balancing Efficiency and Coverage in Human-Robot Dialogue Collection"
} | null | null | null | null | true | null | 18587 | null | Default | null | null |
null | {
"abstract": " Argument component detection (ACD) is an important sub-task in argumentation\nmining. ACD aims at detecting and classifying different argument components in\nnatural language texts. Historical annotations (HAs) are important features the\nhuman annotators consider when they manually perform the ACD task. However, HAs\nare largely ignored by existing automatic ACD techniques. Reinforcement\nlearning (RL) has proven to be an effective method for using HAs in some\nnatural language processing tasks. In this work, we propose a RL-based ACD\ntechnique, and evaluate its performance on two well-annotated corpora. Results\nsuggest that, in terms of classification accuracy, HAs-augmented RL outperforms\nplain RL by at most 17.85%, and outperforms the state-of-the-art supervised\nlearning algorithm by at most 11.94%.\n",
"title": "Reinforcement Learning Based Argument Component Detection"
} | null | null | null | null | true | null | 18588 | null | Default | null | null |
null | {
"abstract": " We present VUNet, a novel view(VU) synthesis method for mobile robots in\ndynamic environments, and its application to the estimation of future\ntraversability. Our method predicts future images for given virtual robot\nvelocity commands using only RGB images at previous and current time steps. The\nfuture images result from applying two types of image changes to the previous\nand current images: 1) changes caused by different camera pose, and 2) changes\ndue to the motion of the dynamic obstacles. We learn to predict these two types\nof changes disjointly using two novel network architectures, SNet and DNet. We\ncombine SNet and DNet to synthesize future images that we pass to our\npreviously presented method GONet to estimate the traversable areas around the\nrobot. Our quantitative and qualitative evaluation indicate that our approach\nfor view synthesis predicts accurate future images in both static and dynamic\nenvironments. We also show that these virtual images can be used to estimate\nfuture traversability correctly. We apply our view synthesis-based\ntraversability estimation method to two applications for assisted\nteleoperation.\n",
"title": "VUNet: Dynamic Scene View Synthesis for Traversability Estimation using an RGB Camera"
} | null | null | null | null | true | null | 18589 | null | Default | null | null |
null | {
"abstract": " We introduce a new class of priors for Bayesian hypothesis testing, which we\nname \"cake priors\". These priors circumvent Bartlett's paradox (also called the\nJeffreys-Lindley paradox); the problem associated with the use of diffuse\npriors leading to nonsensical statistical inferences. Cake priors allow the use\nof diffuse priors (having one's cake) while achieving theoretically justified\ninferences (eating it too). We demonstrate this methodology for Bayesian\nhypotheses tests for scenarios under which the one and two sample t-tests, and\nlinear models are typically derived. The resulting Bayesian test statistic\ntakes the form of a penalized likelihood ratio test statistic. By considering\nthe sampling distribution under the null and alternative hypotheses we show for\nindependent identically distributed regular parametric models that Bayesian\nhypothesis tests using cake priors are Chernoff-consistent, i.e., achieve zero\ntype I and II errors asymptotically. Lindley's paradox is also discussed. We\nargue that a true Lindley's paradox will only occur with small probability for\nlarge sample sizes.\n",
"title": "Bayesian hypothesis tests with diffuse priors: Can we have our cake and eat it too?"
} | null | null | null | null | true | null | 18590 | null | Default | null | null |
null | {
"abstract": " In this paper, a novel multitaper modified group delay function-based\nrepresentation for speech signals is proposed. With a set of phoneme-based\nexperiments, it is shown that the proposed method performs better that an\nexisting multitaper magnitude (MT-MAG) estimation technique, in terms of\nvariance and MSE, both in spectral- and cepstral-domains. In particular, the\nperformance of MT-MOGDF is found to be the best with the Thomson tapers.\nAdditionally, the utility of the MT-MOGDF technique is highlighted in a speaker\nrecognition experimental setup, where an improvement of around $20\\%$ compared\nto the next-best technique is obtained. Moreover, the computational\nrequirements of the proposed technique is comparable to that of MT-MAG. The\nproposed feature can be used in for many speech-related applications; in\nparticular, it is best suited among those that require information of speaker\nand speech.\n",
"title": "On a Novel Speech Representation Using Multitapered Modified Group Delay Function"
} | null | null | null | null | true | null | 18591 | null | Default | null | null |
null | {
"abstract": " This paper studies deterministic consensus networks with discrete-time\ndynamics under persistent flows and non-reciprocal agent interactions. An arc\ndescribing the interaction strength between two agents is said to be persistent\nif its weight function has an infinite $l_1$ norm. We discuss two balance\nconditions on the interactions between agents which generalize the arc-balance\nand cut-balance conditions in the literature respectively. The proposed\nconditions require that such a balance should be satisfied over each time\nwindow of a fixed length instead of at each time instant. We prove that in both\ncases global consensus is reached if and only if the persistent graph, which\nconsists of all the persistent arcs, contains a directed spanning tree. The\nconvergence rates of the system to consensus are also provided in terms of the\ninteractions between agents having taken place. The results are obtained under\na weak condition without assuming the existence of a positive lower bound of\nall the nonzero weights of arcs and are compared with the existing results.\nIllustrative examples are provided to show the critical importance of the\nnontrivial lower boundedness of the self-confidence of the agents.\n",
"title": "Persistent Flows and Non-Reciprocal Interactions in Deterministic Networks"
} | null | null | [
"Computer Science"
]
| null | true | null | 18592 | null | Validated | null | null |
null | {
"abstract": " We investigate possible links between the large-scale and small-scale\nfeatures of solar wind fluctuations across the frequency break separating fluid\nand kinetic regimes. The aim is to correlate the magnetic field fluctuations\npolarization at dissipative scales with the particular state of turbulence\nwithin the inertial range of fluctuations. We found clear correlations between\neach type of polarization within the kinetic regime and fluid parameters within\nthe inertial range. Moreover, for the first time in literature, we showed that\nleft-handed and right-handed polarized fluctuations occupy different areas of\nthe plasma instabilities-temperature anisotropy plot, as expected for\nAlfv$\\acute{\\textrm{e}}$n Ion Cyclotron and Kinetic Alfv$\\acute{\\textrm{e}}$n\nwaves, respectively.\n",
"title": "Linking Fluid and Kinetic Scales in Solar Wind Turbulence"
} | null | null | null | null | true | null | 18593 | null | Default | null | null |
null | {
"abstract": " We consider the \"searching for a trail in a maze\" composite hypothesis\ntesting problem, in which one attempts to detect an anomalous directed path in\na lattice 2D box of side n based on observations on the nodes of the box. Under\nthe signal hypothesis, one observes independent Gaussian variables of unit\nvariance at all nodes, with zero, mean off the anomalous path and mean \\mu_n on\nit. Under the null hypothesis, one observes i.i.d. standard Gaussians on all\nnodes. Arias-Castro et al. (2008) showed that if the unknown directed path\nunder the signal hypothesis has known the initial location, then detection is\npossible (in the minimax sense) if \\mu_n >> 1/\\sqrt log n, while it is not\npossible if \\mu_n << 1/ log n\\sqrt log log n. In this paper, we show that this\nresult continues to hold even when the initial location of the unknown path is\nnot known. As is the case with Arias-Castro et al. (2008), the upper bound here\nalso applies when the path is undirected. The improvement is achieved by\nreplacing the linear detection statistic used in Arias-Castro et al. (2008)\nwith a polynomial statistic, which is obtained by employing a multi-scale\nanalysis on a quadratic statistic to bootstrap its performance. Our analysis is\nmotivated by ideas developed in the context of the analysis of random polymers\nin Lacoin (2010).\n",
"title": "Thresholds For Detecting An Anomalous Path From Noisy Environments"
} | null | null | null | null | true | null | 18594 | null | Default | null | null |
null | {
"abstract": " The main aim of this article is to give a necessary and sufficient condition\nfor a real Bott manifold to admit a spin structure and further give a\ncombinatorial characterization for the spin structure in terms of the\nassociated acyclic digraph.\n",
"title": "On the topology of real Bott manifolds"
} | null | null | [
"Mathematics"
]
| null | true | null | 18595 | null | Validated | null | null |
null | {
"abstract": " We consider relative error low rank approximation of $tensors$ with respect\nto the Frobenius norm: given an order-$q$ tensor $A \\in\n\\mathbb{R}^{\\prod_{i=1}^q n_i}$, output a rank-$k$ tensor $B$ for which\n$\\|A-B\\|_F^2 \\leq (1+\\epsilon)$OPT, where OPT $= \\inf_{\\textrm{rank-}k~A'}\n\\|A-A'\\|_F^2$. Despite the success on obtaining relative error low rank\napproximations for matrices, no such results were known for tensors. One\nstructural issue is that there may be no rank-$k$ tensor $A_k$ achieving the\nabove infinum. Another, computational issue, is that an efficient relative\nerror low rank approximation algorithm for tensors would allow one to compute\nthe rank of a tensor, which is NP-hard. We bypass these issues via (1)\nbicriteria and (2) parameterized complexity solutions:\n(1) We give an algorithm which outputs a rank $k' = O((k/\\epsilon)^{q-1})$\ntensor $B$ for which $\\|A-B\\|_F^2 \\leq (1+\\epsilon)$OPT in $nnz(A) + n \\cdot\n\\textrm{poly}(k/\\epsilon)$ time in the real RAM model. Here $nnz(A)$ is the\nnumber of non-zero entries in $A$.\n(2) We give an algorithm for any $\\delta >0$ which outputs a rank $k$ tensor\n$B$ for which $\\|A-B\\|_F^2 \\leq (1+\\epsilon)$OPT and runs in $ ( nnz(A) + n\n\\cdot \\textrm{poly}(k/\\epsilon) + \\exp(k^2/\\epsilon) ) \\cdot n^\\delta$ time in\nthe unit cost RAM model.\nFor outputting a rank-$k$ tensor, or even a bicriteria solution with\nrank-$Ck$ for a certain constant $C > 1$, we show a $2^{\\Omega(k^{1-o(1)})}$\ntime lower bound under the Exponential Time Hypothesis.\nOur results give the first relative error low rank approximations for tensors\nfor a large number of robust error measures for which nothing was known, as\nwell as column row and tube subset selection. We also obtain new results for\nmatrices, such as $nnz(A)$-time CUR decompositions, improving previous\n$nnz(A)\\log n$-time algorithms, which may be of independent interest.\n",
"title": "Relative Error Tensor Low Rank Approximation"
} | null | null | null | null | true | null | 18596 | null | Default | null | null |
null | {
"abstract": " Boolean matrix factorisation aims to decompose a binary data matrix into an\napproximate Boolean product of two low rank, binary matrices: one containing\nmeaningful patterns, the other quantifying how the observations can be\nexpressed as a combination of these patterns. We introduce the OrMachine, a\nprobabilistic generative model for Boolean matrix factorisation and derive a\nMetropolised Gibbs sampler that facilitates efficient parallel posterior\ninference. On real world and simulated data, our method outperforms all\ncurrently existing approaches for Boolean matrix factorisation and completion.\nThis is the first method to provide full posterior inference for Boolean Matrix\nfactorisation which is relevant in applications, e.g. for controlling false\npositive rates in collaborative filtering and, crucially, improves the\ninterpretability of the inferred patterns. The proposed algorithm scales to\nlarge datasets as we demonstrate by analysing single cell gene expression data\nin 1.3 million mouse brain cells across 11 thousand genes on commodity\nhardware.\n",
"title": "Bayesian Boolean Matrix Factorisation"
} | null | null | [
"Computer Science",
"Statistics"
]
| null | true | null | 18597 | null | Validated | null | null |
null | {
"abstract": " Using a negative gradient flow approach, we generalize and unify some\nexistence theorems for the problem of prescribing $Q$-curvature first by Baird,\nFardoun, and Regbaoui (Calc. Var. 27 75-104) for $4$-manifolds with a possible\nsign-changing curvature candidate then by Brendle (Ann. Math. 158 323-343) for\n$n$-manifolds with even $n$ with positive curvature candidate to the case of\n$n$-manifolds of all even dimension with sign-changing curvature candidates.\nMaking use of the \\L ojasiewicz--Simon inequality, we also address the rate of\nthe convergence.\n",
"title": "Global existence and convergence of $Q$-curvature flow on manifolds of even dimension"
} | null | null | [
"Mathematics"
]
| null | true | null | 18598 | null | Validated | null | null |
null | {
"abstract": " We show that every countable group H with solvable word problem (=computable\ngroup) can be subnormally embedded into a 2-generated group G which also has\nsolvable word problem. Moreover, the membership problem for H < G is also\nsolvable. We also give estimates of time and space complexity of the word\nproblem in G and of the membership problem for H < G.\n",
"title": "Group Embeddings with Algorithmic Properties"
} | null | null | [
"Mathematics"
]
| null | true | null | 18599 | null | Validated | null | null |
null | {
"abstract": " Topological defects unavoidably form at symmetry breaking phase transitions\nin the early Universe. To probe the parameter space of theoretical models and\nset tighter experimental constraints (exploiting the recent advances in\nastrophysical observations), one requires more and more demanding simulations,\nand therefore more hardware resources and computation time. Improving the speed\nand efficiency of existing codes is essential. Here we present a General\nPurpose Graphics Processing Unit implementation of the canonical\nPress-Ryden-Spergel algorithm for the evolution of cosmological domain wall\nnetworks. This is ported to the Open Computing Language standard, and as a\nconsequence significant speed-ups are achieved both in 2D and 3D simulations.\n",
"title": "General purpose graphics-processing-unit implementation of cosmological domain wall network evolution"
} | null | null | null | null | true | null | 18600 | null | Default | null | null |
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