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null | {
"abstract": " Convolutional Neural Networks (CNNs) can learn effective features, though\nhave been shown to suffer from a performance drop when the distribution of the\ndata changes from training to test data. In this paper we analyze the internal\nrepresentations of CNNs and observe that the representations of unseen data in\neach class, spread more (with higher variance) in the embedding space of the\nCNN compared to representations of the training data. More importantly, this\ndifference is more extreme if the unseen data comes from a shifted\ndistribution. Based on this observation, we objectively evaluate the degree of\nrepresentation's variance in each class via eigenvalue decomposition on the\nwithin-class covariance of the internal representations of CNNs and observe the\nsame behaviour. This can be problematic as larger variances might lead to\nmis-classification if the sample crosses the decision boundary of its class. We\napply nearest neighbor classification on the representations and empirically\nshow that the embeddings with the high variance actually have significantly\nworse KNN classification performances, although this could not be foreseen from\ntheir end-to-end classification results. To tackle this problem, we propose\nDeep Within-Class Covariance Analysis (DWCCA), a deep neural network layer that\nsignificantly reduces the within-class covariance of a DNN's representation,\nimproving performance on unseen test data from a shifted distribution. We\nempirically evaluate DWCCA on two datasets for Acoustic Scene Classification\n(DCASE2016 and DCASE2017). We demonstrate that not only does DWCCA\nsignificantly improve the network's internal representation, it also increases\nthe end-to-end classification accuracy, especially when the test set exhibits a\ndistribution shift. By adding DWCCA to a VGG network, we achieve around 6\npercentage points improvement in the case of a distribution mismatch.\n",
"title": "Deep Within-Class Covariance Analysis for Robust Audio Representation Learning"
} | null | null | null | null | true | null | 401 | null | Default | null | null |
null | {
"abstract": " We present an efficient second-order algorithm with\n$\\tilde{O}(\\frac{1}{\\eta}\\sqrt{T})$ regret for the bandit online multiclass\nproblem. The regret bound holds simultaneously with respect to a family of loss\nfunctions parameterized by $\\eta$, for a range of $\\eta$ restricted by the norm\nof the competitor. The family of loss functions ranges from hinge loss\n($\\eta=0$) to squared hinge loss ($\\eta=1$). This provides a solution to the\nopen problem of (J. Abernethy and A. Rakhlin. An efficient bandit algorithm for\n$\\sqrt{T}$-regret in online multiclass prediction? In COLT, 2009). We test our\nalgorithm experimentally, showing that it also performs favorably against\nearlier algorithms.\n",
"title": "Efficient Online Bandit Multiclass Learning with $\\tilde{O}(\\sqrt{T})$ Regret"
} | null | null | null | null | true | null | 402 | null | Default | null | null |
null | {
"abstract": " Swarm systems constitute a challenging problem for reinforcement learning\n(RL) as the algorithm needs to learn decentralized control policies that can\ncope with limited local sensing and communication abilities of the agents.\nWhile it is often difficult to directly define the behavior of the agents,\nsimple communication protocols can be defined more easily using prior knowledge\nabout the given task. In this paper, we propose a number of simple\ncommunication protocols that can be exploited by deep reinforcement learning to\nfind decentralized control policies in a multi-robot swarm environment. The\nprotocols are based on histograms that encode the local neighborhood relations\nof the agents and can also transmit task-specific information, such as the\nshortest distance and direction to a desired target. In our framework, we use\nan adaptation of Trust Region Policy Optimization to learn complex\ncollaborative tasks, such as formation building and building a communication\nlink. We evaluate our findings in a simulated 2D-physics environment, and\ncompare the implications of different communication protocols.\n",
"title": "Local Communication Protocols for Learning Complex Swarm Behaviors with Deep Reinforcement Learning"
} | null | null | null | null | true | null | 403 | null | Default | null | null |
null | {
"abstract": " We describe the design and implementation of an extremely scalable real-time\nRFI mitigation method, based on the offline AOFlagger. All algorithms scale\nlinearly in the number of samples. We describe how we implemented the flagger\nin the LOFAR real-time pipeline, on both CPUs and GPUs. Additionally, we\nintroduce a novel simple history-based flagger that helps reduce the impact of\nour small window on the data.\nBy examining an observation of a known pulsar, we demonstrate that our\nflagger can achieve much higher quality than a simple thresholder, even when\nrunning in real time, on a distributed system. The flagger works on visibility\ndata, but also on raw voltages, and beam formed data. The algorithms are\nscale-invariant, and work on microsecond to second time scales. We are\ncurrently implementing a prototype for the time domain pipeline of the SKA\ncentral signal processor.\n",
"title": "Towards exascale real-time RFI mitigation"
} | null | null | null | null | true | null | 404 | null | Default | null | null |
null | {
"abstract": " Controlling embodied agents with many actuated degrees of freedom is a\nchallenging task. We propose a method that can discover and interpolate between\ncontext dependent high-level actions or body-affordances. These provide an\nabstract, low-dimensional interface indexing high-dimensional and time-\nextended action policies. Our method is related to recent ap- proaches in the\nmachine learning literature but is conceptually simpler and easier to\nimplement. More specifically our method requires the choice of a n-dimensional\ntarget sensor space that is endowed with a distance metric. The method then\nlearns an also n-dimensional embedding of possibly reactive body-affordances\nthat spread as far as possible throughout the target sensor space.\n",
"title": "Learning body-affordances to simplify action spaces"
} | null | null | null | null | true | null | 405 | null | Default | null | null |
null | {
"abstract": " Let $n >3$ and $ 0< k < \\frac{n}{2} $ be integers. In this paper, we\ninvestigate some algebraic properties of the line graph of the graph $\n{Q_n}(k,k+1) $ where $ {Q_n}(k,k+1) $ is the subgraph of the hypercube $Q_n$\nwhich is induced by the set of vertices of weights $k$ and $k+1$. In the first\nstep, we determine the automorphism groups of these graphs for all values of\n$k$. In the second step, we study Cayley properties of the line graph of these\ngraphs. In particular, we show that for $ k>2, $ if $ 2k+1 \\neq n$, then the\nline graph of the graph $ {Q_n}(k,k+1) $ is a vertex-transitive non Cayley\ngraph. Also, we show that the line graph of the graph $ {Q_n}(1,2) $ is a\nCayley graph if and only if $ n$ is a power of a prime $p$.\n",
"title": "Cayley properties of the line graphs induced by of consecutive layers of the hypercube"
} | null | null | null | null | true | null | 406 | null | Default | null | null |
null | {
"abstract": " Recently software development companies started to embrace Machine Learning\n(ML) techniques for introducing a series of advanced functionality in their\nproducts such as personalisation of the user experience, improved search,\ncontent recommendation and automation. The technical challenges for tackling\nthese problems are heavily researched in literature. A less studied area is a\npragmatic approach to the role of humans in a complex modern industrial\nenvironment where ML based systems are developed. Key stakeholders affect the\nsystem from inception and up to operation and maintenance. Product managers\nwant to embed \"smart\" experiences for their users and drive the decisions on\nwhat should be built next; software engineers are challenged to build or\nutilise ML software tools that require skills that are well outside of their\ncomfort zone; legal and risk departments may influence design choices and data\naccess; operations teams are requested to maintain ML systems which are\nnon-stationary in their nature and change behaviour over time; and finally ML\npractitioners should communicate with all these stakeholders to successfully\nbuild a reliable system. This paper discusses some of the challenges we faced\nin Atlassian as we started investing more in the ML space.\n",
"title": "Beyond the technical challenges for deploying Machine Learning solutions in a software company"
} | null | null | [
"Computer Science",
"Statistics"
]
| null | true | null | 407 | null | Validated | null | null |
null | {
"abstract": " Generative Adversarial Networks (GANs) produce systematically better quality\nsamples when class label information is provided., i.e. in the conditional GAN\nsetup. This is still observed for the recently proposed Wasserstein GAN\nformulation which stabilized adversarial training and allows considering high\ncapacity network architectures such as ResNet. In this work we show how to\nboost conditional GAN by augmenting available class labels. The new classes\ncome from clustering in the representation space learned by the same GAN model.\nThe proposed strategy is also feasible when no class information is available,\ni.e. in the unsupervised setup. Our generated samples reach state-of-the-art\nInception scores for CIFAR-10 and STL-10 datasets in both supervised and\nunsupervised setup.\n",
"title": "Class-Splitting Generative Adversarial Networks"
} | null | null | [
"Statistics"
]
| null | true | null | 408 | null | Validated | null | null |
null | {
"abstract": " We study the phase space dynamics of cosmological models in the theoretical\nformulations of non-minimal metric-torsion couplings with a scalar field, and\ninvestigate in particular the critical points which yield stable solutions\nexhibiting cosmic acceleration driven by the {\\em dark energy}. The latter is\ndefined in a way that it effectively has no direct interaction with the\ncosmological fluid, although in an equivalent scalar-tensor cosmological setup\nthe scalar field interacts with the fluid (which we consider to be the\npressureless dust). Determining the conditions for the existence of the stable\ncritical points we check their physical viability, in both Einstein and Jordan\nframes. We also verify that in either of these frames, the evolution of the\nuniverse at the corresponding stable points matches with that given by the\nrespective exact solutions we have found in an earlier work (arXiv: 1611.00654\n[gr-qc]). We not only examine the regions of physical relevance for the\ntrajectories in the phase space when the coupling parameter is varied, but also\ndemonstrate the evolution profiles of the cosmological parameters of interest\nalong fiducial trajectories in the effectively non-interacting scenarios, in\nboth Einstein and Jordan frames.\n",
"title": "Dynamical system analysis of dark energy models in scalar coupled metric-torsion theories"
} | null | null | [
"Physics"
]
| null | true | null | 409 | null | Validated | null | null |
null | {
"abstract": " In this work, we propose an end-to-end deep architecture that jointly learns\nto detect obstacles and estimate their depth for MAV flight applications. Most\nof the existing approaches either rely on Visual SLAM systems or on depth\nestimation models to build 3D maps and detect obstacles. However, for the task\nof avoiding obstacles this level of complexity is not required. Recent works\nhave proposed multi task architectures to both perform scene understanding and\ndepth estimation. We follow their track and propose a specific architecture to\njointly estimate depth and obstacles, without the need to compute a global map,\nbut maintaining compatibility with a global SLAM system if needed. The network\narchitecture is devised to exploit the joint information of the obstacle\ndetection task, that produces more reliable bounding boxes, with the depth\nestimation one, increasing the robustness of both to scenario changes. We call\nthis architecture J-MOD$^{2}$. We test the effectiveness of our approach with\nexperiments on sequences with different appearance and focal lengths and\ncompare it to SotA multi task methods that jointly perform semantic\nsegmentation and depth estimation. In addition, we show the integration in a\nfull system using a set of simulated navigation experiments where a MAV\nexplores an unknown scenario and plans safe trajectories by using our detection\nmodel.\n",
"title": "J-MOD$^{2}$: Joint Monocular Obstacle Detection and Depth Estimation"
} | null | null | [
"Computer Science"
]
| null | true | null | 410 | null | Validated | null | null |
null | {
"abstract": " In this paper, we prove that there exists a dimensional constant $\\delta > 0$\nsuch that given any background Kähler metric $\\omega$, the Calabi flow with\ninitial data $u_0$ satisfying \\begin{equation*} \\partial \\bar \\partial u_0 \\in\nL^\\infty (M) \\text{ and } (1- \\delta )\\omega < \\omega_{u_0} < (1+\\delta\n)\\omega, \\end{equation*} admits a unique short time solution and it becomes\nsmooth immediately, where $\\omega_{u_0} : = \\omega +\\sqrt{-1}\\partial\n\\bar\\partial u_0$. The existence time depends on initial data $u_0$ and the\nmetric $\\omega$. As a corollary, we get that Calabi flow has short time\nexistence for any initial data satisfying \\begin{equation*} \\partial \\bar\n\\partial u_0 \\in C^0(M) \\text{ and } \\omega_{u_0} > 0, \\end{equation*} which\nshould be interpreted as a \"continuous Kähler metric\". A main technical\ningredient is Schauder-type estimates for biharmonic heat equation on\nRiemannian manifolds with time weighted Hölder norms.\n",
"title": "The Calabi flow with rough initial data"
} | null | null | [
"Mathematics"
]
| null | true | null | 411 | null | Validated | null | null |
null | {
"abstract": " To probe the star-formation (SF) processes, we present results of an analysis\nof the molecular cloud G35.20$-$0.74 (hereafter MCG35.2) using multi-frequency\nobservations. The MCG35.2 is depicted in a velocity range of 30-40 km s$^{-1}$.\nAn almost horseshoe-like structure embedded within the MCG35.2 is evident in\nthe infrared and millimeter images and harbors the previously known sites,\nultra-compact/hyper-compact G35.20$-$0.74N H\\,{\\sc ii} region, Ap2-1, and\nMercer 14 at its base. The site, Ap2-1 is found to be excited by a radio\nspectral type of B0.5V star where the distribution of 20 cm and H$\\alpha$\nemission is surrounded by the extended molecular hydrogen emission. Using the\n{\\it Herschel} 160-500 $\\mu$m and photometric 1-24 $\\mu$m data analysis,\nseveral embedded clumps and clusters of young stellar objects (YSOs) are\ninvestigated within the MCG35.2, revealing the SF activities. Majority of the\nYSOs clusters and massive clumps (500-4250 M$_{\\odot}$) are seen toward the\nhorseshoe-like structure. The position-velocity analysis of $^{13}$CO emission\nshows a blue-shifted peak (at 33 km s$^{-1}$) and a red-shifted peak (at 37 km\ns$^{-1}$) interconnected by lower intensity intermediated velocity emission,\ntracing a broad bridge feature. The presence of such broad bridge feature\nsuggests the onset of a collision between molecular components in the MCG35.2.\nA noticeable change in the H-band starlight mean polarization angles has also\nbeen observed in the MCG35.2, probably tracing the interaction between\nmolecular components. Taken together, it seems that the cloud-cloud collision\nprocess has influenced the birth of massive stars and YSOs clusters in the\nMCG35.2.\n",
"title": "Star Formation Activity in the molecular cloud G35.20$-$0.74: onset of cloud-cloud collision"
} | null | null | null | null | true | null | 412 | null | Default | null | null |
null | {
"abstract": " We present novel oblivious routing algorithms for both splittable and\nunsplittable multicommodity flow. Our algorithm for minimizing congestion for\n\\emph{unsplittable} multicommodity flow is the first oblivious routing\nalgorithm for this setting. As an intermediate step towards this algorithm, we\npresent a novel generalization of Valiant's classical load balancing scheme for\npacket-switched networks to arbitrary graphs, which is of independent interest.\nOur algorithm for minimizing congestion for \\emph{splittable} multicommodity\nflow improves upon the state-of-the-art, in terms of both running time and\nperformance, for graphs that exhibit good expansion guarantees. Our algorithms\nrely on diffusing traffic via iterative applications of the random walk\noperator. Consequently, the performance guarantees of our algorithms are\nderived from the convergence of the random walk operator to the stationary\ndistribution and are expressed in terms of the spectral gap of the graph (which\ndominates the mixing time).\n",
"title": "Oblivious Routing via Random Walks"
} | null | null | null | null | true | null | 413 | null | Default | null | null |
null | {
"abstract": " We study functional graphs generated by quadratic polynomials over prime\nfields. We introduce efficient algorithms for methodical computations and\nprovide the values of various direct and cumulative statistical parameters of\ninterest. These include: the number of connected functional graphs, the number\nof graphs having a maximal cycle, the number of cycles of fixed size, the\nnumber of components of fixed size, as well as the shape of trees extracted\nfrom functional graphs. We particularly focus on connected functional graphs,\nthat is, the graphs which contain only one component (and thus only one cycle).\nBased on the results of our computations, we formulate several conjectures\nhighlighting the similarities and differences between these functional graphs\nand random mappings.\n",
"title": "On Functional Graphs of Quadratic Polynomials"
} | null | null | null | null | true | null | 414 | null | Default | null | null |
null | {
"abstract": " Helmholtz decomposition theorem for vector fields is usually presented with\ntoo strong restrictions on the fields and only for time independent fields.\nBlumenthal showed in 1905 that decomposition is possible for any asymptotically\nweakly decreasing vector field. He used a regularization method in his proof\nwhich can be extended to prove the theorem even for vector fields\nasymptotically increasing sublinearly. Blumenthal's result is then applied to\nthe time-dependent fields of the dipole radiation and an artificial sublinearly\nincreasing field.\n",
"title": "Helmholtz decomposition theorem and Blumenthal's extension by regularization"
} | null | null | null | null | true | null | 415 | null | Default | null | null |
null | {
"abstract": " We use Richter's $2$-primary proof of Gray's conjecture to give a homotopy\ndecomposition of the fibre $\\Omega^3S^{17}\\{2\\}$ of the $H$-space squaring map\non the triple loop space of the $17$-sphere. This induces a splitting of the\nmod-$2$ homotopy groups $\\pi_\\ast(S^{17}; \\mathbb{Z}/2\\mathbb{Z})$ in terms of\nthe integral homotopy groups of the fibre of the double suspension\n$E^2:S^{2n-1} \\to \\Omega^2S^{2n+1}$ and refines a result of Cohen and Selick,\nwho gave similar decompositions for $S^5$ and $S^9$. We relate these\ndecompositions to various Whitehead products in the homotopy groups of mod-$2$\nMoore spaces and Stiefel manifolds to show that the Whitehead square $[i_{2n},\ni_{2n}]$ of the inclusion of the bottom cell of the Moore space $P^{2n+1}(2)$\nis divisible by $2$ if and only if $2n=2, 4, 8$ or $16$.\n",
"title": "A homotopy decomposition of the fibre of the squaring map on $Ω^3S^{17}$"
} | null | null | null | null | true | null | 416 | null | Default | null | null |
null | {
"abstract": " We show that certain orderable groups admit no isolated left orders. The\ngroups we consider are cyclic amalgamations of a free group with a general\norderable group, the HNN extensions of free groups over cyclic subgroups, and a\nparticular class of one-relator groups. In order to prove the results about\norders, we develop perturbation techniques for actions of these groups on the\nline.\n",
"title": "Spaces of orders of some one-relator groups"
} | null | null | null | null | true | null | 417 | null | Default | null | null |
null | {
"abstract": " Machine learning classifiers are known to be vulnerable to inputs maliciously\nconstructed by adversaries to force misclassification. Such adversarial\nexamples have been extensively studied in the context of computer vision\napplications. In this work, we show adversarial attacks are also effective when\ntargeting neural network policies in reinforcement learning. Specifically, we\nshow existing adversarial example crafting techniques can be used to\nsignificantly degrade test-time performance of trained policies. Our threat\nmodel considers adversaries capable of introducing small perturbations to the\nraw input of the policy. We characterize the degree of vulnerability across\ntasks and training algorithms, for a subclass of adversarial-example attacks in\nwhite-box and black-box settings. Regardless of the learned task or training\nalgorithm, we observe a significant drop in performance, even with small\nadversarial perturbations that do not interfere with human perception. Videos\nare available at this http URL.\n",
"title": "Adversarial Attacks on Neural Network Policies"
} | null | null | null | null | true | null | 418 | null | Default | null | null |
null | {
"abstract": " Tidal streams of disrupting dwarf galaxies orbiting around their host galaxy\noffer a unique way to constrain the shape of galactic gravitational potentials.\nSuch streams can be used as leaning tower gravitational experiments on galactic\nscales. The most well motivated modification of gravity proposed as an\nalternative to dark matter on galactic scales is Milgromian dynamics (MOND),\nand we present here the first ever N-body simulations of the dynamical\nevolution of the disrupting Sagittarius dwarf galaxy in this framework. Using a\nrealistic baryonic mass model for the Milky Way, we attempt to reproduce the\npresent-day spatial and kinematic structure of the Sagittarius dwarf and its\nimmense tidal stream that wraps around the Milky Way. With very little freedom\non the original structure of the progenitor, constrained by the total\nluminosity of the Sagittarius structure and by the observed stellar mass-size\nrelation for isolated dwarf galaxies, we find reasonable agreement between our\nsimulations and observations of this system. The observed stellar velocities in\nthe leading arm can be reproduced if we include a massive hot gas corona around\nthe Milky Way that is flattened in the direction of the principal plane of its\nsatellites. This is the first time that tidal dissolution in MOND has been\ntested rigorously at these mass and acceleration scales.\n",
"title": "Stellar streams as gravitational experiments I. The case of Sagittarius"
} | null | null | null | null | true | null | 419 | null | Default | null | null |
null | {
"abstract": " The response of an electron system to electromagnetic fields with sharp\nspatial variations is strongly dependent on quantum electronic properties, even\nin ambient conditions, but difficult to access experimentally. We use\npropagating graphene plasmons, together with an engineered dielectric-metallic\nenvironment, to probe the graphene electron liquid and unveil its detailed\nelectronic response at short wavelengths.The near-field imaging experiments\nreveal a parameter-free match with the full theoretical quantum description of\nthe massless Dirac electron gas, in which we identify three types of quantum\neffects as keys to understanding the experimental response of graphene to\nshort-ranged terahertz electric fields. The first type is of single-particle\nnature and is related to shape deformations of the Fermi surface during a\nplasmon oscillations. The second and third types are a many-body effect\ncontrolled by the inertia and compressibility of the interacting electron\nliquid in graphene. We demonstrate how, in principle, our experimental approach\ncan determine the full spatiotemporal response of an electron system.\n",
"title": "Tuning quantum non-local effects in graphene plasmonics"
} | null | null | null | null | true | null | 420 | null | Default | null | null |
null | {
"abstract": " A new generation of solar instruments provides improved spectral, spatial,\nand temporal resolution, thus facilitating a better understanding of dynamic\nprocesses on the Sun. High-resolution observations often reveal\nmultiple-component spectral line profiles, e.g., in the near-infrared He I\n10830 \\AA\\ triplet, which provides information about the chromospheric velocity\nand magnetic fine structure. We observed an emerging flux region, including two\nsmall pores and an arch filament system, on 2015 April 17 with the 'very fast\nspectroscopic mode' of the GREGOR Infrared Spectrograph (GRIS) situated at the\n1.5-meter GREGOR solar telescope at Observatorio del Teide, Tenerife, Spain. We\ndiscuss this method of obtaining fast (one per minute) spectral scans of the\nsolar surface and its potential to follow dynamic processes on the Sun. We\ndemonstrate the performance of the 'very fast spectroscopic mode' by tracking\nchromospheric high-velocity features in the arch filament system.\n",
"title": "Flows along arch filaments observed in the GRIS 'very fast spectroscopic mode'"
} | null | null | null | null | true | null | 421 | null | Default | null | null |
null | {
"abstract": " In the past decade, the information security and threat landscape has grown\nsignificantly making it difficult for a single defender to defend against all\nattacks at the same time. This called for introduc- ing information sharing, a\nparadigm in which threat indicators are shared in a community of trust to\nfacilitate defenses. Standards for representation, exchange, and consumption of\nindicators are pro- posed in the literature, although various issues are\nundermined. In this paper, we rethink information sharing for actionable\nintelli- gence, by highlighting various issues that deserve further explo-\nration. We argue that information sharing can benefit from well- defined use\nmodels, threat models, well-understood risk by mea- surement and robust\nscoring, well-understood and preserved pri- vacy and quality of indicators and\nrobust mechanism to avoid free riding behavior of selfish agent. We call for\nusing the differential nature of data and community structures for optimizing\nsharing.\n",
"title": "Rethinking Information Sharing for Actionable Threat Intelligence"
} | null | null | null | null | true | null | 422 | null | Default | null | null |
null | {
"abstract": " Permutation polynomials over finite fields have wide applications in many\nareas of science and engineering. In this paper, we present six new classes of\npermutation trinomials over $\\mathbb{F}_{2^n}$ which have explicit forms by\ndetermining the solutions of some equations.\n",
"title": "More new classes of permutation trinomials over $\\mathbb{F}_{2^n}$"
} | null | null | [
"Mathematics"
]
| null | true | null | 423 | null | Validated | null | null |
null | {
"abstract": " Ben-David and Shelah proved that if $\\lambda$ is a singular strong-limit\ncardinal and $2^\\lambda=\\lambda^+$, then $\\square^*_\\lambda$ entails the\nexistence of a normal $\\lambda$-distributive $\\lambda^+$-Aronszajn tree. Here,\nit is proved that the same conclusion remains valid after replacing the\nhypothesis $\\square^*_\\lambda$ by $\\square(\\lambda^+,{<}\\lambda)$.\nAs $\\square(\\lambda^+,{<}\\lambda)$ does not impose a bound on the order-type\nof the witnessing clubs, our construction is necessarily different from that of\nBen-David and Shelah, and instead uses walks on ordinals augmented with club\nguessing.\nA major component of this work is the study of postprocessing functions and\ntheir effect on square sequences. A byproduct of this study is the finding that\nfor $\\kappa$ regular uncountable, $\\square(\\kappa)$ entails the existence of a\npartition of $\\kappa$ into $\\kappa$ many fat sets. When contrasted with a\nclassic model of Magidor, this shows that it is equiconsistent with the\nexistence of a weakly compact cardinal that $\\omega_2$ cannot be split into two\nfat sets.\n",
"title": "Distributive Aronszajn trees"
} | null | null | [
"Mathematics"
]
| null | true | null | 424 | null | Validated | null | null |
null | {
"abstract": " The real Scarf II potential is discussed as a radial problem. This potential\nhas been studied extensively as a one-dimensional problem, and now these\nresults are used to construct its bound and resonance solutions for $l=0$ by\nsetting the origin at some arbitrary value of the coordinate. The solutions\nwith appropriate boundary conditions are composed as the linear combination of\nthe two independent solutions of the Schrödinger equation. The asymptotic\nexpression of these solutions is used to construct the $S_0(k)$ s-wave\n$S$-matrix, the poles of which supply the $k$ values corresponding to the\nbound, resonance and anti-bound solutions. The location of the discrete energy\neigenvalues is analyzed, and the relation of the solutions of the radial and\none-dimensional Scarf II potentials is discussed. It is shown that the\ngeneralized Woods--Saxon potential can be generated from the Rosen--Morse II\npotential in the same way as the radial Scarf II potential is obtained from its\none-dimensional correspondent. Based on this analogy, possible applications are\nalso pointed out.\n",
"title": "Analytical solutions for the radial Scarf II potential"
} | null | null | null | null | true | null | 425 | null | Default | null | null |
null | {
"abstract": " This paper presents a novel model for multimodal learning based on gated\nneural networks. The Gated Multimodal Unit (GMU) model is intended to be used\nas an internal unit in a neural network architecture whose purpose is to find\nan intermediate representation based on a combination of data from different\nmodalities. The GMU learns to decide how modalities influence the activation of\nthe unit using multiplicative gates. It was evaluated on a multilabel scenario\nfor genre classification of movies using the plot and the poster. The GMU\nimproved the macro f-score performance of single-modality approaches and\noutperformed other fusion strategies, including mixture of experts models.\nAlong with this work, the MM-IMDb dataset is released which, to the best of our\nknowledge, is the largest publicly available multimodal dataset for genre\nprediction on movies.\n",
"title": "Gated Multimodal Units for Information Fusion"
} | null | null | null | null | true | null | 426 | null | Default | null | null |
null | {
"abstract": " In a single winner election with several candidates and ranked choice or\nrating scale ballots, a Condorcet winner is one who wins all their two way\nraces by majority rule or MR. A voting system has Condorcet consistency or CC\nif it names any Condorcet winner the winner. Many voting systems lack CC, but a\nthree step line of reasoning is used here to show why it is necessary. In step\n1 we show that we can dismiss all the electoral criteria which conflict with\nCC. In step 2 we point out that CC follows almost automatically if we can agree\nthat MR is the only acceptable system for elections with two candidates. In\nstep 3 we make that argument for MR. This argument itself has three parts.\nFirst, in races with two candidates, the only well known alternatives to MR can\nsometimes name as winner a candidate who is preferred over their opponent by\nonly one voter, with all others preferring the opponent. That is unacceptable.\nSecond, those same systems are also extremely susceptible to strategic\ninsincere voting. Third, in simulation studies using spatial models with two\ncandidates, the best known alternative to MR picks the best or most centrist\ncandidate significantly less often than MR does.\n",
"title": "Why Condorcet Consistency is Essential"
} | null | null | null | null | true | null | 427 | null | Default | null | null |
null | {
"abstract": " In the framework of the Einstein-Maxwell-aether theory we study the\nbirefringence effect, which can occur in the pp-wave symmetric dynamic aether.\nThe dynamic aether is considered to be latently birefringent quasi-medium,\nwhich displays this hidden property if and only if the aether motion is\nnon-uniform, i.e., when the aether flow is characterized by the non-vanishing\nexpansion, shear, vorticity or acceleration. In accordance with the\ndynamo-optical scheme of description of the interaction between electromagnetic\nwaves and the dynamic aether, we shall model the susceptibility tensors by the\nterms linear in the covariant derivative of the aether velocity four-vector.\nWhen the pp-wave modes appear in the dynamic aether, we deal with a\ngravitationally induced degeneracy removal with respect to hidden\nsusceptibility parameters. As a consequence, the phase velocities of\nelectromagnetic waves possessing orthogonal polarizations do not coincide, thus\ndisplaying the birefringence effect. Two electromagnetic field configurations\nare studied in detail: longitudinal and transversal with respect to the aether\npp-wave front. For both cases the solutions are found, which reveal anomalies\nin the electromagnetic response on the action of the pp-wave aether mode.\n",
"title": "Birefringence induced by pp-wave modes in an electromagnetically active dynamic aether"
} | null | null | null | null | true | null | 428 | null | Default | null | null |
null | {
"abstract": " The $p$-set, which is in a simple analytic form, is well distributed in unit\ncubes. The well-known Weil's exponential sum theorem presents an upper bound of\nthe exponential sum over the $p$-set. Based on the result, one shows that the\n$p$-set performs well in numerical integration, in compressed sensing as well\nas in UQ. However, $p$-set is somewhat rigid since the cardinality of the\n$p$-set is a prime $p$ and the set only depends on the prime number $p$. The\npurpose of this paper is to present generalizations of $p$-sets, say\n$\\mathcal{P}_{d,p}^{{\\mathbf a},\\epsilon}$, which is more flexible.\nParticularly, when a prime number $p$ is given, we have many different choices\nof the new $p$-sets. Under the assumption that Goldbach conjecture holds, for\nany even number $m$, we present a point set, say ${\\mathcal L}_{p,q}$, with\ncardinality $m-1$ by combining two different new $p$-sets, which overcomes a\nmajor bottleneck of the $p$-set. We also present the upper bounds of the\nexponential sums over $\\mathcal{P}_{d,p}^{{\\mathbf a},\\epsilon}$ and ${\\mathcal\nL}_{p,q}$, which imply these sets have many potential applications.\n",
"title": "On generalizations of $p$-sets and their applications"
} | null | null | null | null | true | null | 429 | null | Default | null | null |
null | {
"abstract": " This paper presents the design and implementation of a Human Interface for a\nhousekeeper robot. It bases on the idea of making the robot understand the\nhuman needs without making the human go through the details of robots work, for\nexample, the way that the robot implements the work or the method that the\nrobot uses to plan the path in order to reach the work area. The interface\ncommands based on idioms of the natural human language and designed in a manner\nthat the user gives the robot several commands with their execution date/time.\n",
"title": "Robot human interface for housekepeer with wireless capabilities"
} | null | null | null | null | true | null | 430 | null | Default | null | null |
null | {
"abstract": " This work proposes a new algorithm for training a re-weighted L2 Support\nVector Machine (SVM), inspired on the re-weighted Lasso algorithm of Candès\net al. and on the equivalence between Lasso and SVM shown recently by Jaggi. In\nparticular, the margin required for each training vector is set independently,\ndefining a new weighted SVM model. These weights are selected to be binary, and\nthey are automatically adapted during the training of the model, resulting in a\nvariation of the Frank-Wolfe optimization algorithm with essentially the same\ncomputational complexity as the original algorithm. As shown experimentally,\nthis algorithm is computationally cheaper to apply since it requires less\niterations to converge, and it produces models with a sparser representation in\nterms of support vectors and which are more stable with respect to the\nselection of the regularization hyper-parameter.\n",
"title": "Modified Frank-Wolfe Algorithm for Enhanced Sparsity in Support Vector Machine Classifiers"
} | null | null | [
"Computer Science",
"Statistics"
]
| null | true | null | 431 | null | Validated | null | null |
null | {
"abstract": " Learning-based approaches to robotic manipulation are limited by the\nscalability of data collection and accessibility of labels. In this paper, we\npresent a multi-task domain adaptation framework for instance grasping in\ncluttered scenes by utilizing simulated robot experiments. Our neural network\ntakes monocular RGB images and the instance segmentation mask of a specified\ntarget object as inputs, and predicts the probability of successfully grasping\nthe specified object for each candidate motor command. The proposed transfer\nlearning framework trains a model for instance grasping in simulation and uses\na domain-adversarial loss to transfer the trained model to real robots using\nindiscriminate grasping data, which is available both in simulation and the\nreal world. We evaluate our model in real-world robot experiments, comparing it\nwith alternative model architectures as well as an indiscriminate grasping\nbaseline.\n",
"title": "Multi-Task Domain Adaptation for Deep Learning of Instance Grasping from Simulation"
} | null | null | null | null | true | null | 432 | null | Default | null | null |
null | {
"abstract": " A 1-ended finitely presented group has semistable fundamental group at\n$\\infty$ if it acts geometrically on some (equivalently any) simply connected\nand locally finite complex $X$ with the property that any two proper rays in\n$X$ are properly homotopic. If $G$ has semistable fundamental group at $\\infty$\nthen one can unambiguously define the fundamental group at $\\infty$ for $G$.\nThe problem, asking if all finitely presented groups have semistable\nfundamental group at $\\infty$ has been studied for over 40 years. If $G$ is an\nascending HNN extension of a finitely presented group then indeed, $G$ has\nsemistable fundamental group at $\\infty$, but since the early 1980's it has\nbeen suggested that the finitely presented groups that are ascending HNN\nextensions of {\\it finitely generated} groups may include a group with\nnon-semistable fundamental group at $\\infty$. Ascending HNN extensions\nnaturally break into two classes, those with bounded depth and those with\nunbounded depth. Our main theorem shows that bounded depth finitely presented\nascending HNN extensions of finitely generated groups have semistable\nfundamental group at $\\infty$. Semistability is equivalent to two weaker\nasymptotic conditions on the group holding simultaneously. We show one of these\nconditions holds for all ascending HNN extensions, regardless of depth. We give\na technique for constructing ascending HNN extensions with unbounded depth.\nThis work focuses attention on a class of groups that may contain a group with\nnon-semistable fundamental group at $\\infty$.\n",
"title": "Bounded Depth Ascending HNN Extensions and $π_1$-Semistability at $\\infty$"
} | null | null | [
"Mathematics"
]
| null | true | null | 433 | null | Validated | null | null |
null | {
"abstract": " Developing and testing algorithms for autonomous vehicles in real world is an\nexpensive and time consuming process. Also, in order to utilize recent advances\nin machine intelligence and deep learning we need to collect a large amount of\nannotated training data in a variety of conditions and environments. We present\na new simulator built on Unreal Engine that offers physically and visually\nrealistic simulations for both of these goals. Our simulator includes a physics\nengine that can operate at a high frequency for real-time hardware-in-the-loop\n(HITL) simulations with support for popular protocols (e.g. MavLink). The\nsimulator is designed from the ground up to be extensible to accommodate new\ntypes of vehicles, hardware platforms and software protocols. In addition, the\nmodular design enables various components to be easily usable independently in\nother projects. We demonstrate the simulator by first implementing a quadrotor\nas an autonomous vehicle and then experimentally comparing the software\ncomponents with real-world flights.\n",
"title": "AirSim: High-Fidelity Visual and Physical Simulation for Autonomous Vehicles"
} | null | null | null | null | true | null | 434 | null | Default | null | null |
null | {
"abstract": " Let $G$ be a finitely generated pro-$p$ group, equipped with the $p$-power\nseries. The associated metric and Hausdorff dimension function give rise to the\nHausdorff spectrum, which consists of the Hausdorff dimensions of closed\nsubgroups of $G$. In the case where $G$ is $p$-adic analytic, the Hausdorff\ndimension function is well understood; in particular, the Hausdorff spectrum\nconsists of finitely many rational numbers closely linked to the analytic\ndimensions of subgroups of $G$.\nConversely, it is a long-standing open question whether the finiteness of the\nHausdorff spectrum implies that $G$ is $p$-adic analytic. We prove that the\nanswer is yes, in a strong sense, under the extra condition that $G$ is\nsoluble.\nFurthermore, we explore the problem and related questions also for other\nfiltration series, such as the lower $p$-series, the Frattini series, the\nmodular dimension subgroup series and quite general filtration series. For\ninstance, we prove, for odd primes $p$, that every countably based pro-$p$\ngroup $G$ with an open subgroup mapping onto 2 copies of the $p$-adic integers\nadmits a filtration series such that the corresponding Hausdorff spectrum\ncontains an infinite real interval.\n",
"title": "Hausdorff dimensions in $p$-adic analytic groups"
} | null | null | null | null | true | null | 435 | null | Default | null | null |
null | {
"abstract": " Brain-Machine Interaction (BMI) system motivates interesting and promising\nresults in forward/feedback control consistent with human intention. It holds\ngreat promise for advancements in patient care and applications to\nneurorehabilitation. Here, we propose a novel neurofeedback-based BCI robotic\nplatform using a personalized social robot in order to assist patients having\ncognitive deficits through bilateral rehabilitation and mental training. For\ninitial testing of the platform, electroencephalography (EEG) brainwaves of a\nhuman user were collected in real time during tasks of imaginary movements.\nFirst, the brainwaves associated with imagined body kinematics parameters were\ndecoded to control a cursor on a computer screen in training protocol. Then,\nthe experienced subject was able to interact with a social robot via our\nreal-time BMI robotic platform. Corresponding to subject's imagery performance,\nhe/she received specific gesture movements and eye color changes as\nneural-based feedback from the robot. This hands-free neurofeedback interaction\nnot only can be used for mind control of a social robot's movements, but also\nsets the stage for application to enhancing and recovering mental abilities\nsuch as attention via training in humans by providing real-time neurofeedback\nfrom a social robot.\n",
"title": "Real-time brain machine interaction via social robot gesture control"
} | null | null | null | null | true | null | 436 | null | Default | null | null |
null | {
"abstract": " Road networks in cities are massive and is a critical component of mobility.\nFast response to defects, that can occur not only due to regular wear and tear\nbut also because of extreme events like storms, is essential. Hence there is a\nneed for an automated system that is quick, scalable and cost-effective for\ngathering information about defects. We propose a system for city-scale road\naudit, using some of the most recent developments in deep learning and semantic\nsegmentation. For building and benchmarking the system, we curated a dataset\nwhich has annotations required for road defects. However, many of the labels\nrequired for road audit have high ambiguity which we overcome by proposing a\nlabel hierarchy. We also propose a multi-step deep learning model that segments\nthe road, subdivide the road further into defects, tags the frame for each\ndefect and finally localizes the defects on a map gathered using GPS. We\nanalyze and evaluate the models on image tagging as well as segmentation at\ndifferent levels of the label hierarchy.\n",
"title": "City-Scale Road Audit System using Deep Learning"
} | null | null | null | null | true | null | 437 | null | Default | null | null |
null | {
"abstract": " In this Letter, we study the motion and wake-patterns of freely rising and\nfalling cylinders in quiescent fluid. We show that the amplitude of oscillation\nand the overall system-dynamics are intricately linked to two parameters: the\nparticle's mass-density relative to the fluid $m^* \\equiv \\rho_p/\\rho_f$ and\nits relative moment-of-inertia $I^* \\equiv {I}_p/{I}_f$. This supersedes the\ncurrent understanding that a critical mass density ($m^*\\approx$ 0.54) alone\ntriggers the sudden onset of vigorous vibrations. Using over 144 combinations\nof ${m}^*$ and $I^*$, we comprehensively map out the parameter space covering\nvery heavy ($m^* > 10$) to very buoyant ($m^* < 0.1$) particles. The entire\ndata collapses into two scaling regimes demarcated by a transitional Strouhal\nnumber, $St_t \\approx 0.17$. $St_t$ separates a mass-dominated regime from a\nregime dominated by the particle's moment of inertia. A shift from one regime\nto the other also marks a gradual transition in the wake-shedding pattern: from\nthe classical $2S$~(2-Single) vortex mode to a $2P$~(2-Pairs) vortex mode.\nThus, auto-rotation can have a significant influence on the trajectories and\nwakes of freely rising isotropic bodies.\n",
"title": "Mass and moment of inertia govern the transition in the dynamics and wakes of freely rising and falling cylinders"
} | null | null | [
"Physics"
]
| null | true | null | 438 | null | Validated | null | null |
null | {
"abstract": " Theory of Mind is the ability to attribute mental states (beliefs, intents,\nknowledge, perspectives, etc.) to others and recognize that these mental states\nmay differ from one's own. Theory of Mind is critical to effective\ncommunication and to teams demonstrating higher collective performance. To\neffectively leverage the progress in Artificial Intelligence (AI) to make our\nlives more productive, it is important for humans and AI to work well together\nin a team. Traditionally, there has been much emphasis on research to make AI\nmore accurate, and (to a lesser extent) on having it better understand human\nintentions, tendencies, beliefs, and contexts. The latter involves making AI\nmore human-like and having it develop a theory of our minds. In this work, we\nargue that for human-AI teams to be effective, humans must also develop a\ntheory of AI's mind (ToAIM) - get to know its strengths, weaknesses, beliefs,\nand quirks. We instantiate these ideas within the domain of Visual Question\nAnswering (VQA). We find that using just a few examples (50), lay people can be\ntrained to better predict responses and oncoming failures of a complex VQA\nmodel. We further evaluate the role existing explanation (or interpretability)\nmodalities play in helping humans build ToAIM. Explainable AI has received\nconsiderable scientific and popular attention in recent times. Surprisingly, we\nfind that having access to the model's internal states - its confidence in its\ntop-k predictions, explicit or implicit attention maps which highlight regions\nin the image (and words in the question) the model is looking at (and listening\nto) while answering a question about an image - do not help people better\npredict its behavior.\n",
"title": "It Takes Two to Tango: Towards Theory of AI's Mind"
} | null | null | null | null | true | null | 439 | null | Default | null | null |
null | {
"abstract": " We study families of varieties endowed with polarized canonical eigensystems\nof several maps, inducing canonical heights on the dominating variety as well\nas on the \"good\" fibers of the family. We show explicitely the dependence on\nthe parameter for global and local canonical heights defined by Kawaguchi when\nthe fibers change, extending previous works of J. Silverman and others.\nFinally, fixing an absolute value $v \\in K$ and a variety $V/K$, we descript\nthe Kawaguchi`s canonical local height $\\hat{\\lambda}_{V,E,\\mathcal{Q},}(.,v)$\nas an intersection number, provided that the polarized system $(V,\\mathcal{Q})$\nhas a certain weak Néron model over Spec$(\\mathcal{O}_v)$ to be defined and\nunder some conditions depending on the special fiber. With this we extend\nNéron's work strengthening Silverman's results, which were for systems\nhaving only one map.\n",
"title": "On variation of dynamical canonical heights, and Intersection numbers"
} | null | null | null | null | true | null | 440 | null | Default | null | null |
null | {
"abstract": " Large-scale extragalactic magnetic fields may induce conversions between\nvery-high-energy photons and axionlike particles (ALPs), thereby shielding the\nphotons from absorption on the extragalactic background light. However, in\nsimplified \"cell\" models, used so far to represent extragalactic magnetic\nfields, this mechanism would be strongly suppressed by current astrophysical\nbounds. Here we consider a recent model of extragalactic magnetic fields\nobtained from large-scale cosmological simulations. Such simulated magnetic\nfields would have large enhancement in the filaments of matter. As a result,\nphoton-ALP conversions would produce a significant spectral hardening for\ncosmic TeV photons. This effect would be probed with the upcoming Cherenkov\nTelescope Array detector. This possible detection would give a unique chance to\nperform a tomography of the magnetized cosmic web with ALPs.\n",
"title": "Enhancing the Spectral Hardening of Cosmic TeV Photons by Mixing with Axionlike Particles in the Magnetized Cosmic Web"
} | null | null | null | null | true | null | 441 | null | Default | null | null |
null | {
"abstract": " Predicting the future state of a system has always been a natural motivation\nfor science and practical applications. Such a topic, beyond its obvious\ntechnical and societal relevance, is also interesting from a conceptual point\nof view. This owes to the fact that forecasting lends itself to two equally\nradical, yet opposite methodologies. A reductionist one, based on the first\nprinciples, and the naive inductivist one, based only on data. This latter view\nhas recently gained some attention in response to the availability of\nunprecedented amounts of data and increasingly sophisticated algorithmic\nanalytic techniques. The purpose of this note is to assess critically the role\nof big data in reshaping the key aspects of forecasting and in particular the\nclaim that bigger data leads to better predictions. Drawing on the\nrepresentative example of weather forecasts we argue that this is not generally\nthe case. We conclude by suggesting that a clever and context-dependent\ncompromise between modelling and quantitative analysis stands out as the best\nforecasting strategy, as anticipated nearly a century ago by Richardson and von\nNeumann.\n",
"title": "Forecasting in the light of Big Data"
} | null | null | null | null | true | null | 442 | null | Default | null | null |
null | {
"abstract": " We show that for an elliptic curve E defined over a number field K, the group\nE(A) of points of E over the adele ring A of K is a topological group that can\nbe analyzed in terms of the Galois representation associated to the torsion\npoints of E. An explicit description of E(A) is given, and we prove that for K\nof degree n, almost all elliptic curves over K have an adelic point group\ntopologically isomorphic to a universal group depending on n. We also show that\nthere exist infinitely many elliptic curves over K having a different adelic\npoint group.\n",
"title": "Adelic point groups of elliptic curves"
} | null | null | null | null | true | null | 443 | null | Default | null | null |
null | {
"abstract": " Wireless backhaul communication has been recently realized with large\nantennas operating in the millimeter wave (mmWave) frequency band and\nimplementing highly directional beamforming. In this paper, we focus on the\nalignment problem of narrow beams between fixed position network nodes in\nmmWave backhaul systems that are subject to small displacements due to wind\nflow or ground vibration. We consider nodes equipped with antenna arrays that\nare capable of performing only analog processing and communicate through\nwireless channels including a line-of-sight component. Aiming at minimizing the\ntime needed to achieve beam alignment, we present an efficient method that\ncapitalizes on the exchange of position information between the nodes to design\ntheir beamforming and combining vectors. Some numerical results on the outage\nprobability with the proposed beam alignment method offer useful preliminary\ninsights on the impact of some system and operation parameters.\n",
"title": "Position Aided Beam Alignment for Millimeter Wave Backhaul Systems with Large Phased Arrays"
} | null | null | null | null | true | null | 444 | null | Default | null | null |
null | {
"abstract": " Feature engineering has been the key to the success of many prediction\nmodels. However, the process is non-trivial and often requires manual feature\nengineering or exhaustive searching. DNNs are able to automatically learn\nfeature interactions; however, they generate all the interactions implicitly,\nand are not necessarily efficient in learning all types of cross features. In\nthis paper, we propose the Deep & Cross Network (DCN) which keeps the benefits\nof a DNN model, and beyond that, it introduces a novel cross network that is\nmore efficient in learning certain bounded-degree feature interactions. In\nparticular, DCN explicitly applies feature crossing at each layer, requires no\nmanual feature engineering, and adds negligible extra complexity to the DNN\nmodel. Our experimental results have demonstrated its superiority over the\nstate-of-art algorithms on the CTR prediction dataset and dense classification\ndataset, in terms of both model accuracy and memory usage.\n",
"title": "Deep & Cross Network for Ad Click Predictions"
} | null | null | null | null | true | null | 445 | null | Default | null | null |
null | {
"abstract": " We investigate the spin structure of a uni-axial chiral magnet near the\ntransition temperatures in low fields perpendicular to the helical axis. We\nfind a fan-type modulation structure where the clockwise and counterclockwise\nwindings appear alternatively along the propagation direction of the modulation\nstructure. This structure is often realized in a Yoshimori-type (non-chiral)\nhelimagnet but it is rarely realized in a chiral helimagnet. To discuss\nunderlying physics of this structure, we reconsider the phase diagram (phase\nboundary and crossover lines) through the free energy and asymptotic behaviors\nof isolated solitons. The fan structure appears slightly below the phase\nboundary of the continuous transition of instability-type. In this region,\nthere are no solutions containing any types of isolated solitons to the mean\nfield equations.\n",
"title": "Fan-type spin structure in uni-axial chiral magnets"
} | null | null | null | null | true | null | 446 | null | Default | null | null |
null | {
"abstract": " Several natural satellites of the giant planets have shown evidence of a\nglobal internal ocean, coated by a thin, icy crust. This crust is probably\nviscoelastic, which would alter its rotational response. This response would\ntranslate into several rotational quantities, i.e. the obliquity, and the\nlibrations at different frequencies, for which the crustal elasticity reacts\ndifferently. This study aims at modelling the global response of the\nviscoelastic crust. For that, I derive the time-dependency of the tensor of\ninertia, which I combine with the time evolution of the rotational quantities,\nthanks to an iterative algorithm. This algorithm combines numerical simulations\nof the rotation with a digital filtering of the resulting tensor of inertia.\nThe algorithm works very well in the elastic case, provided the problem is not\nresonant. However, considering tidal dissipation adds different phase lags to\nthe oscillating contributions, which challenge the convergence of the\nalgorithm.\n",
"title": "Rotation of a synchronous viscoelastic shell"
} | null | null | [
"Physics"
]
| null | true | null | 447 | null | Validated | null | null |
null | {
"abstract": " A number of fundamental quantities in statistical signal processing and\ninformation theory can be expressed as integral functions of two probability\ndensity functions. Such quantities are called density functionals as they map\ndensity functions onto the real line. For example, information divergence\nfunctions measure the dissimilarity between two probability density functions\nand are useful in a number of applications. Typically, estimating these\nquantities requires complete knowledge of the underlying distribution followed\nby multi-dimensional integration. Existing methods make parametric assumptions\nabout the data distribution or use non-parametric density estimation followed\nby high-dimensional integration. In this paper, we propose a new alternative.\nWe introduce the concept of \"data-driven basis functions\" - functions of\ndistributions whose value we can estimate given only samples from the\nunderlying distributions without requiring distribution fitting or direct\nintegration. We derive a new data-driven complete basis that is similar to the\ndeterministic Bernstein polynomial basis and develop two methods for performing\nbasis expansions of functionals of two distributions. We also show that the new\nbasis set allows us to approximate functions of distributions as closely as\ndesired. Finally, we evaluate the methodology by developing data driven\nestimators for the Kullback-Leibler divergences and the Hellinger distance and\nby constructing empirical estimates of tight bounds on the Bayes error rate.\n",
"title": "Direct estimation of density functionals using a polynomial basis"
} | null | null | null | null | true | null | 448 | null | Default | null | null |
null | {
"abstract": " Let $E/\\mathbb{Q}$ be an elliptic curve of level $N$ and rank equal to $1$.\nLet $p$ be a prime of ordinary reduction. We experimentally study conjecture\n$4$ of B. Mazur and J. Tate in his article \"Refined Conjectures of the Birch\nand Swinnerton-Dyer Type\". We report the computational evidence.\n",
"title": "Experimental Evidence on a Refined Conjecture of the BSD type"
} | null | null | null | null | true | null | 449 | null | Default | null | null |
null | {
"abstract": " The Tu--Deng Conjecture is concerned with the sum of digits $w(n)$ of $n$ in\nbase~$2$ (the Hamming weight of the binary expansion of $n$) and states the\nfollowing: assume that $k$ is a positive integer and $1\\leq t<2^k-1$. Then\n\\[\\Bigl \\lvert\\Bigl\\{(a,b)\\in\\bigl\\{0,\\ldots,2^k-2\\bigr\\}^2:a+b\\equiv t\\bmod\n2^k-1, w(a)+w(b)<k\\Bigr\\}\\Bigr \\rvert\\leq 2^{k-1}.\\]\nWe prove that the Tu--Deng Conjecture holds almost surely in the following\nsense: the proportion of $t\\in[1,2^k-2]$ such that the above inequality holds\napproaches $1$ as $k\\rightarrow\\infty$.\nMoreover, we prove that the Tu--Deng Conjecture implies a conjecture due to\nT.~W.~Cusick concerning the sum of digits of $n$ and $n+t$.\n",
"title": "The Tu--Deng Conjecture holds almost surely"
} | null | null | [
"Computer Science",
"Mathematics"
]
| null | true | null | 450 | null | Validated | null | null |
null | {
"abstract": " In this paper, we made an extension to the convergence analysis of the\ndynamics of two-layered bias-free networks with one $ReLU$ output. We took into\nconsideration two popular regularization terms: the $\\ell_1$ and $\\ell_2$ norm\nof the parameter vector $w$, and added it to the square loss function with\ncoefficient $\\lambda/2$. We proved that when $\\lambda$ is small, the weight\nvector $w$ converges to the optimal solution $\\hat{w}$ (with respect to the new\nloss function) with probability $\\geq (1-\\varepsilon)(1-A_d)/2$ under random\ninitiations in a sphere centered at the origin, where $\\varepsilon$ is a small\nvalue and $A_d$ is a constant. Numerical experiments including phase diagrams\nand repeated simulations verified our theory.\n",
"title": "Convergence Analysis of the Dynamics of a Special Kind of Two-Layered Neural Networks with $\\ell_1$ and $\\ell_2$ Regularization"
} | null | null | [
"Computer Science",
"Statistics"
]
| null | true | null | 451 | null | Validated | null | null |
null | {
"abstract": " We further progress along the line of Ref. [Phys. Rev. {\\bf A 94}, 043614\n(2016)] where a functional for Fermi systems with anomalously large $s$-wave\nscattering length $a_s$ was proposed that has no free parameters. The\nfunctional is designed to correctly reproduce the unitary limit in Fermi gases\ntogether with the leading-order contributions in the s- and p-wave channels at\nlow density. The functional is shown to be predictive up to densities\n$\\sim0.01$ fm$^{-3}$ that is much higher densities compared to the Lee-Yang\nfunctional, valid for $\\rho < 10^{-6}$ fm$^{-3}$. The form of the functional\nretained in this work is further motivated. It is shown that the new functional\ncorresponds to an expansion of the energy in $(a_s k_F)$ and $(r_e k_F)$ to all\norders, where $r_e$ is the effective range and $k_F$ is the Fermi momentum. One\nconclusion from the present work is that, except in the extremely low--density\nregime, nuclear systems can be treated perturbatively in $-(a_s k_F)^{-1}$ with\nrespect to the unitary limit. Starting from the functional, we introduce\ndensity--dependent scales and show that scales associated to the bare\ninteraction are strongly renormalized by medium effects. As a consequence, some\nof the scales at play around saturation are dominated by the unitary gas\nproperties and not directly to low-energy constants. For instance, we show that\nthe scale in the s-wave channel around saturation is proportional to the\nso-called Bertsch parameter $\\xi_0$ and becomes independent of $a_s$. We also\npoint out that these scales are of the same order of magnitude than those\nempirically obtained in the Skyrme energy density functional. We finally\npropose a slight modification of the functional such that it becomes accurate\nup to the saturation density $\\rho\\simeq 0.16$ fm$^{-3}$.\n",
"title": "From bare interactions, low--energy constants and unitary gas to nuclear density functionals without free parameters: application to neutron matter"
} | null | null | null | null | true | null | 452 | null | Default | null | null |
null | {
"abstract": " Marker-based and marker-less optical skeletal motion-capture methods use an\noutside-in arrangement of cameras placed around a scene, with viewpoints\nconverging on the center. They often create discomfort by possibly needed\nmarker suits, and their recording volume is severely restricted and often\nconstrained to indoor scenes with controlled backgrounds. We therefore propose\na new method for real-time, marker-less and egocentric motion capture which\nestimates the full-body skeleton pose from a lightweight stereo pair of fisheye\ncameras that are attached to a helmet or virtual-reality headset. It combines\nthe strength of a new generative pose estimation framework for fisheye views\nwith a ConvNet-based body-part detector trained on a new automatically\nannotated and augmented dataset. Our inside-in method captures full-body motion\nin general indoor and outdoor scenes, and also crowded scenes.\n",
"title": "EgoCap: Egocentric Marker-less Motion Capture with Two Fisheye Cameras (Extended Abstract)"
} | null | null | null | null | true | null | 453 | null | Default | null | null |
null | {
"abstract": " Diffusion maps are an emerging data-driven technique for non-linear\ndimensionality reduction, which are especially useful for the analysis of\ncoherent structures and nonlinear embeddings of dynamical systems. However, the\ncomputational complexity of the diffusion maps algorithm scales with the number\nof observations. Thus, long time-series data presents a significant challenge\nfor fast and efficient embedding. We propose integrating the Nyström method\nwith diffusion maps in order to ease the computational demand. We achieve a\nspeedup of roughly two to four times when approximating the dominant diffusion\nmap components.\n",
"title": "Diffusion Maps meet Nyström"
} | null | null | null | null | true | null | 454 | null | Default | null | null |
null | {
"abstract": " We present a set of effective outflow/open boundary conditions and an\nassociated algorithm for simulating the dynamics of multiphase flows consisting\nof $N$ ($N\\geqslant 2$) immiscible incompressible fluids in domains involving\noutflows or open boundaries. These boundary conditions are devised based on the\nproperties of energy stability and reduction consistency. The energy stability\nproperty ensures that the contributions of these boundary conditions to the\nenergy balance will not cause the total energy of the N-phase system to\nincrease over time. Therefore, these open/outflow boundary conditions are very\neffective in overcoming the backflow instability in multiphase systems. The\nreduction consistency property ensures that if some fluid components are absent\nfrom the N-phase system then these N-phase boundary conditions will reduce to\nthose corresponding boundary conditions for the equivalent smaller system. Our\nnumerical algorithm for the proposed boundary conditions together with the\nN-phase governing equations involves only the solution of a set of de-coupled\nindividual Helmholtz-type equations within each time step, and the resultant\nlinear algebraic systems after discretization involve only constant and\ntime-independent coefficient matrices which can be pre-computed. Therefore, the\nalgorithm is computationally very efficient and attractive. We present\nextensive numerical experiments for flow problems involving multiple fluid\ncomponents and inflow/outflow boundaries to test the proposed method. In\nparticular, we compare in detail the simulation results of a three-phase\ncapillary wave problem with Prosperetti's exact physical solution and\ndemonstrate that the method developed herein produces physically accurate\nresults.\n",
"title": "Multiphase Flows of N Immiscible Incompressible Fluids: An Outflow/Open Boundary Condition and Algorithm"
} | null | null | null | null | true | null | 455 | null | Default | null | null |
null | {
"abstract": " The recent detection of two faint and extended star clusters in the central\nregions of two Local Group dwarf galaxies, Eridanus II and Andromeda XXV,\nraises the question of whether clusters with such low densities can survive the\ntidal field of cold dark matter haloes with central density cusps. Using both\nanalytic arguments and a suite of collisionless N-body simulations, I show that\nthese clusters are extremely fragile and quickly disrupted in the presence of\ncentral cusps $\\rho\\sim r^{-\\alpha}$ with $\\alpha\\gtrsim 0.2$. Furthermore, the\nscenario in which the clusters where originally more massive and sank to the\ncenter of the halo requires extreme fine tuning and does not naturally\nreproduce the observed systems. In turn, these clusters are long lived in cored\nhaloes, whose central regions are safe shelters for $\\alpha\\lesssim 0.2$. The\nonly viable scenario for hosts that have preserved their primoridal cusp to the\npresent time is that the clusters formed at rest at the bottom of the\npotential, which is easily tested by measurement of the clusters proper\nvelocity within the host. This offers means to readily probe the central\ndensity profile of two dwarf galaxies as faint as $L_V\\sim5\\times 10^5 L_\\odot$\nand $L_V\\sim6\\times10^4 L_\\odot$, in which stellar feedback is unlikely to be\neffective.\n",
"title": "Deadly dark matter cusps vs faint and extended star clusters: Eridanus II and Andromeda XXV"
} | null | null | null | null | true | null | 456 | null | Default | null | null |
null | {
"abstract": " Fundamental relations between information and estimation have been\nestablished in the literature for the continuous-time Gaussian and Poisson\nchannels, in a long line of work starting from the classical representation\ntheorems by Duncan and Kabanov respectively. In this work, we demonstrate that\nsuch relations hold for a much larger family of continuous-time channels. We\nintroduce the family of semi-martingale channels where the channel output is a\nsemi-martingale stochastic process, and the channel input modulates the\ncharacteristics of the semi-martingale. For these channels, which includes as a\nspecial case the continuous time Gaussian and Poisson models, we establish new\nrepresentations relating the mutual information between the channel input and\noutput to an optimal causal filtering loss, thereby unifying and considerably\nextending results from the Gaussian and Poisson settings. Extensions to the\nsetting of mismatched estimation are also presented where the relative entropy\nbetween the laws governing the output of the channel under two different input\ndistributions is equal to the cumulative difference between the estimation loss\nincurred by using the mismatched and optimal causal filters respectively. The\nmain tool underlying these results is the Doob--Meyer decomposition of a class\nof likelihood ratio sub-martingales. The results in this work can be viewed as\nthe continuous-time analogues of recent generalizations for relations between\ninformation and estimation for discrete-time Lévy channels.\n",
"title": "Mutual Information, Relative Entropy and Estimation Error in Semi-martingale Channels"
} | null | null | [
"Computer Science"
]
| null | true | null | 457 | null | Validated | null | null |
null | {
"abstract": " Galaxy cluster centring is a key issue for precision cosmology studies using\ngalaxy surveys. Mis-identification of central galaxies causes systematics in\nvarious studies such as cluster lensing, satellite kinematics, and galaxy\nclustering. The red-sequence Matched-filter Probabilistic Percolation\n(redMaPPer) estimates the probability that each member galaxy is central from\nphotometric information rather than specifying one central galaxy. The\nredMaPPer estimates can be used for calibrating the off-centring effect,\nhowever, the centring algorithm has not previously been well-tested. We test\nthe centring probabilities of redMaPPer cluster catalog using the projected\ncross correlation between redMaPPer clusters with photometric red galaxies and\ngalaxy-galaxy lensing. We focus on the subsample of redMaPPer clusters in which\nthe redMaPPer central galaxies (RMCGs) are not the brightest member galaxies\n(BMEM) and both of them have spectroscopic redshift. This subsample represents\nnearly 10% of the whole cluster sample. We find a clear difference in the\ncross-correlation measurements between RMCGs and BMEMs, and the estimated\ncentring probability is 74$\\pm$10% for RMCGs and 13$\\pm$4% for BMEMs in the\nGaussian offset model and 78$\\pm$9% for RMCGs and 5$\\pm$5% for BMEMs in the NFW\noffset model. These values are in agreement with the centring probability\nvalues reported by redMaPPer (75% for RMCG and 10% for BMEMs) within 1$\\sigma$.\nOur analysis provides a strong consistency test of the redMaPPer centring\nprobabilities. Our results suggest that redMaPPer centring probabilities are\nreliably estimated. We confirm that the brightest galaxy in the cluster is not\nalways the central galaxy as has been shown in previous works.\n",
"title": "Testing redMaPPer centring probabilities using galaxy clustering and galaxy-galaxy lensing"
} | null | null | null | null | true | null | 458 | null | Default | null | null |
null | {
"abstract": " The goal of this article is to provide an useful criterion of positivity and\nwell-posedness for a wide range of infinite dimensional semilinear abstract\nCauchy problems. This criterion is based on some weak assumptions on the\nnon-linear part of the semilinear problem and on the existence of a strongly\ncontinuous semigroup generated by the differential operator. To illustrate a\nlarge variety of applications, we exhibit the feasibility of this criterion\nthrough three examples in mathematical biology: epidemiology, predator-prey\ninteractions and oncology.\n",
"title": "Criterion of positivity for semilinear problems with applications in biology"
} | null | null | [
"Mathematics"
]
| null | true | null | 459 | null | Validated | null | null |
null | {
"abstract": " The ongoing progress in quantum theory emphasizes the crucial role of the\nvery basic principles of quantum theory. However, this is not properly followed\nin teaching quantum mechanics on the graduate and undergraduate levels of\nphysics studies. The existing textbooks typically avoid the axiomatic\npresentation of the theory. We emphasize usefulness of the systematic,\naxiomatic approach to the basics of quantum theory as well as its importance in\nthe light of the modern scientific-research context.\n",
"title": "Axiomatic quantum mechanics: Necessity and benefits for the physics studies"
} | null | null | [
"Physics"
]
| null | true | null | 460 | null | Validated | null | null |
null | {
"abstract": " Non-conding RNAs play a key role in the post-transcriptional regulation of\nmRNA translation and turnover in eukaryotes. miRNAs, in particular, interact\nwith their target RNAs through protein-mediated, sequence-specific binding,\ngiving rise to extended and highly heterogeneous miRNA-RNA interaction\nnetworks. Within such networks, competition to bind miRNAs can generate an\neffective positive coupling between their targets. Competing endogenous RNAs\n(ceRNAs) can in turn regulate each other through miRNA-mediated crosstalk.\nAlbeit potentially weak, ceRNA interactions can occur both dynamically,\naffecting e.g. the regulatory clock, and at stationarity, in which case ceRNA\nnetworks as a whole can be implicated in the composition of the cell's\nproteome. Many features of ceRNA interactions, including the conditions under\nwhich they become significant, can be unraveled by mathematical and in silico\nmodels. We review the understanding of the ceRNA effect obtained within such\nframeworks, focusing on the methods employed to quantify it, its role in the\nprocessing of gene expression noise, and how network topology can determine its\nreach.\n",
"title": "Kinetic modelling of competition and depletion of shared miRNAs by competing endogenous RNAs"
} | null | null | null | null | true | null | 461 | null | Default | null | null |
null | {
"abstract": " We show that in Grayson's model of higher algebraic $K$-theory using binary\nacyclic complexes, the complexes of length two suffice to generate the whole\ngroup. Moreover, we prove that the comparison map from Nenashev's model for\n$K_1$ to Grayson's model for $K_1$ is an isomorphism. It follows that algebraic\n$K$-theory of exact categories commutes with infinite products.\n",
"title": "Shortening binary complexes and commutativity of $K$-theory with infinite products"
} | null | null | null | null | true | null | 462 | null | Default | null | null |
null | {
"abstract": " We study the min-cost seed selection problem in online social networks, where\nthe goal is to select a set of seed nodes with the minimum total cost such that\nthe expected number of influenced nodes in the network exceeds a predefined\nthreshold. We propose several algorithms that outperform the previous studies\nboth on the theoretical approximation ratios and on the experimental\nperformance. Under the case where the nodes have heterogeneous costs, our\nalgorithms are the first bi- criteria approximation algorithms with polynomial\nrunning time and provable logarithmic performance bounds using a general\ncontagion model. Under the case where the users have uniform costs, our\nalgorithms achieve logarithmic approximation ratio and provable time complexity\nwhich is smaller than that of existing algorithms in orders of magnitude. We\nconduct extensive experiments using real social networks. The experimental\nresults show that, our algorithms significantly outperform the existing\nalgorithms both on the total cost and on the running time, and also scale well\nto billion-scale networks.\n",
"title": "Cost-Effective Seed Selection in Online Social Networks"
} | null | null | null | null | true | null | 463 | null | Default | null | null |
null | {
"abstract": " We propose a new splitting criterion for a meta-learning approach to\nmulticlass classifier design that adaptively merges the classes into a\ntree-structured hierarchy of increasingly difficult binary classification\nproblems. The classification tree is constructed from empirical estimates of\nthe Henze-Penrose bounds on the pairwise Bayes misclassification rates that\nrank the binary subproblems in terms of difficulty of classification. The\nproposed empirical estimates of the Bayes error rate are computed from the\nminimal spanning tree (MST) of the samples from each pair of classes. Moreover,\na meta-learning technique is presented for quantifying the one-vs-rest Bayes\nerror rate for each individual class from a single MST on the entire dataset.\nExtensive simulations on benchmark datasets show that the proposed hierarchical\nmethod can often be learned much faster than competing methods, while achieving\ncompetitive accuracy.\n",
"title": "Fast Meta-Learning for Adaptive Hierarchical Classifier Design"
} | null | null | null | null | true | null | 464 | null | Default | null | null |
null | {
"abstract": " Variational approaches for the calculation of vibrational wave functions and\nenergies are a natural route to obtain highly accurate results with\ncontrollable errors. However, the unfavorable scaling and the resulting high\ncomputational cost of standard variational approaches limit their application\nto small molecules with only few vibrational modes. Here, we demonstrate how\nthe density matrix renormalization group (DMRG) can be exploited to optimize\nvibrational wave functions (vDMRG) expressed as matrix product states. We study\nthe convergence of these calculations with respect to the size of the local\nbasis of each mode, the number of renormalized block states, and the number of\nDMRG sweeps required. We demonstrate the high accuracy achieved by vDMRG for\nsmall molecules that were intensively studied in the literature. We then\nproceed to show that the complete fingerprint region of the sarcosyn-glycin\ndipeptide can be calculated with vDMRG.\n",
"title": "Vibrational Density Matrix Renormalization Group"
} | null | null | null | null | true | null | 465 | null | Default | null | null |
null | {
"abstract": " In this work, we present a methodology that enables an agent to make\nefficient use of its exploratory actions by autonomously identifying possible\nobjectives in its environment and learning them in parallel. The identification\nof objectives is achieved using an online and unsupervised adaptive clustering\nalgorithm. The identified objectives are learned (at least partially) in\nparallel using Q-learning. Using a simulated agent and environment, it is shown\nthat the converged or partially converged value function weights resulting from\noff-policy learning can be used to accumulate knowledge about multiple\nobjectives without any additional exploration. We claim that the proposed\napproach could be useful in scenarios where the objectives are initially\nunknown or in real world scenarios where exploration is typically a time and\nenergy intensive process. The implications and possible extensions of this work\nare also briefly discussed.\n",
"title": "Identification and Off-Policy Learning of Multiple Objectives Using Adaptive Clustering"
} | null | null | [
"Computer Science"
]
| null | true | null | 466 | null | Validated | null | null |
null | {
"abstract": " Recent studies on diffusion-based sampling methods have shown that Langevin\nMonte Carlo (LMC) algorithms can be beneficial for non-convex optimization, and\nrigorous theoretical guarantees have been proven for both asymptotic and\nfinite-time regimes. Algorithmically, LMC-based algorithms resemble the\nwell-known gradient descent (GD) algorithm, where the GD recursion is perturbed\nby an additive Gaussian noise whose variance has a particular form. Fractional\nLangevin Monte Carlo (FLMC) is a recently proposed extension of LMC, where the\nGaussian noise is replaced by a heavy-tailed {\\alpha}-stable noise. As opposed\nto its Gaussian counterpart, these heavy-tailed perturbations can incur large\njumps and it has been empirically demonstrated that the choice of\n{\\alpha}-stable noise can provide several advantages in modern machine learning\nproblems, both in optimization and sampling contexts. However, as opposed to\nLMC, only asymptotic convergence properties of FLMC have been yet established.\nIn this study, we analyze the non-asymptotic behavior of FLMC for non-convex\noptimization and prove finite-time bounds for its expected suboptimality. Our\nresults show that the weak-error of FLMC increases faster than LMC, which\nsuggests using smaller step-sizes in FLMC. We finally extend our results to the\ncase where the exact gradients are replaced by stochastic gradients and show\nthat similar results hold in this setting as well.\n",
"title": "Non-Asymptotic Analysis of Fractional Langevin Monte Carlo for Non-Convex Optimization"
} | null | null | [
"Computer Science",
"Statistics"
]
| null | true | null | 467 | null | Validated | null | null |
null | {
"abstract": " We use automatic speech recognition to assess spoken English learner\npronunciation based on the authentic intelligibility of the learners' spoken\nresponses determined from support vector machine (SVM) classifier or deep\nlearning neural network model predictions of transcription correctness. Using\nnumeric features produced by PocketSphinx alignment mode and many recognition\npasses searching for the substitution and deletion of each expected phoneme and\ninsertion of unexpected phonemes in sequence, the SVM models achieve 82 percent\nagreement with the accuracy of Amazon Mechanical Turk crowdworker\ntranscriptions, up from 75 percent reported by multiple independent\nresearchers. Using such features with SVM classifier probability prediction\nmodels can help computer-aided pronunciation teaching (CAPT) systems provide\nintelligibility remediation.\n",
"title": "Spoken English Intelligibility Remediation with PocketSphinx Alignment and Feature Extraction Improves Substantially over the State of the Art"
} | null | null | null | null | true | null | 468 | null | Default | null | null |
null | {
"abstract": " We consider bilinear optimal control problems, whose objective functionals do\nnot depend on the controls. Hence, bang-bang solutions will appear. We\ninvestigate sufficient second-order conditions for bang-bang controls, which\nguarantee local quadratic growth of the objective functional in $L^1$. In\naddition, we prove that for controls that are not bang-bang, no such growth can\nbe expected. Finally, we study the finite-element discretization, and prove\nerror estimates of bang-bang controls in $L^1$-norms.\n",
"title": "Second-Order Analysis and Numerical Approximation for Bang-Bang Bilinear Control Problems"
} | null | null | null | null | true | null | 469 | null | Default | null | null |
null | {
"abstract": " We carry out a comprehensive analysis of letter frequencies in contemporary\nwritten Marathi. We determine sets of letters which statistically predominate\nany large generic Marathi text, and use these sets to estimate the entropy of\nMarathi.\n",
"title": "On the letter frequencies and entropy of written Marathi"
} | null | null | null | null | true | null | 470 | null | Default | null | null |
null | {
"abstract": " A hybrid mobile/fixed device cloud that harnesses sensing, computing,\ncommunication, and storage capabilities of mobile and fixed devices in the\nfield as well as those of computing and storage servers in remote datacenters\nis envisioned. Mobile device clouds can be harnessed to enable innovative\npervasive applications that rely on real-time, in-situ processing of sensor\ndata collected in the field. To support concurrent mobile applications on the\ndevice cloud, a robust and secure distributed computing framework, called\nMaestro, is proposed. The key components of Maestro are (i) a task scheduling\nmechanism that employs controlled task replication in addition to task\nreallocation for robustness and (ii) Dedup for task deduplication among\nconcurrent pervasive workflows. An architecture-based solution that relies on\ntask categorization and authorized access to the categories of tasks is\nproposed for different levels of protection. Experimental evaluation through\nprototype testbed of Android- and Linux-based mobile devices as well as\nsimulations is performed to demonstrate Maestro's capabilities.\n",
"title": "Robust Orchestration of Concurrent Application Workflows in Mobile Device Clouds"
} | null | null | null | null | true | null | 471 | null | Default | null | null |
null | {
"abstract": " Despite numerous studies the exact nature of the order parameter in\nsuperconducting Sr2RuO4 remains unresolved. We have extended previous\nsmall-angle neutron scattering studies of the vortex lattice in this material\nto a wider field range, higher temperatures, and with the field applied close\nto both the <100> and <110> basal plane directions. Measurements at high field\nwere made possible by the use of both spin polarization and analysis to improve\nthe signal-to-noise ratio. Rotating the field towards the basal plane causes a\ndistortion of the square vortex lattice observed for H // <001>, and also a\nsymmetry change to a distorted triangular symmetry for fields close to <100>.\nThe vortex lattice distortion allows us to determine the intrinsic\nsuperconducting anisotropy between the c-axis and the Ru-O basal plane,\nyielding a value of ~60 at low temperature and low to intermediate fields. This\ngreatly exceeds the upper critical field anisotropy of ~20 at low temperature,\nreminiscent of Pauli limiting. Indirect evidence for Pauli paramagnetic effects\non the unpaired quasiparticles in the vortex cores are observed, but a direct\ndetection lies below the measurement sensitivity. The superconducting\nanisotropy is found to be independent of temperature but increases for fields >\n1 T, indicating multiband superconductvity in Sr2RuO4. Finally, the temperature\ndependence of the scattered intensity provides further support for gap nodes or\ndeep minima in the superconducting gap.\n",
"title": "Anisotropy and multiband superconductivity in Sr2RuO4"
} | null | null | null | null | true | null | 472 | null | Default | null | null |
null | {
"abstract": " We study $SU(N)$ Quantum Chromodynamics (QCD) in 3+1 dimensions with $N_f$\ndegenerate fundamental quarks with mass $m$ and a $\\theta$-parameter. For\ngeneric $m$ and $\\theta$ the theory has a single gapped vacuum. However, as\n$\\theta$ is varied through $\\theta=\\pi$ for large $m$ there is a first order\ntransition. For $N_f=1$ the first order transition line ends at a point with a\nmassless $\\eta'$ particle (for all $N$) and for $N_f>1$ the first order\ntransition ends at $m=0$, where, depending on the value of $N_f$, the IR theory\nhas free Nambu-Goldstone bosons, an interacting conformal field theory, or a\nfree gauge theory. Even when the $4d$ bulk is smooth, domain walls and\ninterfaces can have interesting phase transitions separating different $3d$\nphases. These turn out to be the phases of the recently studied $3d$\nChern-Simons matter theories, thus relating the dynamics of QCD$_4$ and\nQCD$_3$, and, in particular, making contact with the recently discussed\ndualities in 2+1 dimensions. For example, when the massless $4d$ theory has an\n$SU(N_f)$ sigma model, the domain wall theory at low (nonzero) mass supports a\n$3d$ massless $CP^{N_f-1}$ nonlinear $\\sigma$-model with a Wess-Zumino term, in\nagreement with the conjectured dynamics in 2+1 dimensions.\n",
"title": "Time-Reversal Breaking in QCD$_4$, Walls, and Dualities in 2+1 Dimensions"
} | null | null | null | null | true | null | 473 | null | Default | null | null |
null | {
"abstract": " Investigation of the autoignition delay of the butanol isomers has been\nperformed at elevated pressures of 15 bar and 30 bar and low to intermediate\ntemperatures of 680-860 K. The reactivity of the stoichiometric isomers of\nbutanol, in terms of inverse ignition delay, was ranked as n-butanol >\nsec-butanol ~ iso-butanol > tert-butanol at a compressed pressure of 15 bar but\nchanged to n-butanol > tert-butanol > sec-butanol > iso-butanol at 30 bar. For\nthe temperature and pressure conditions in this study, no NTC or two-stage\nignition behavior were observed. However, for both of the compressed pressures\nstudied in this work, tert-butanol exhibited unique pre-ignition heat release\ncharacteristics. As such, tert-butanol was further studied at two additional\nequivalence ratios ($\\phi$ = 0.5 and 2.0) to help determine the cause of the\nheat release.\n",
"title": "Comparative Investigation of the High Pressure Autoignition of the Butanol Isomers"
} | null | null | [
"Physics"
]
| null | true | null | 474 | null | Validated | null | null |
null | {
"abstract": " Choi et. al (2011) introduced a minimum spanning tree (MST)-based method\ncalled CLGrouping, for constructing tree-structured probabilistic graphical\nmodels, a statistical framework that is commonly used for inferring\nphylogenetic trees. While CLGrouping works correctly if there is a unique MST,\nwe observe an indeterminacy in the method in the case that there are multiple\nMSTs. In this work we remove this indeterminacy by introducing so-called\nvertex-ranked MSTs. We note that the effectiveness of CLGrouping is inversely\nrelated to the number of leaves in the MST. This motivates the problem of\nfinding a vertex-ranked MST with the minimum number of leaves (MLVRMST). We\nprovide a polynomial time algorithm for the MLVRMST problem, and prove its\ncorrectness for graphs whose edges are weighted with tree-additive distances.\n",
"title": "Selecting optimal minimum spanning trees that share a topological correspondence with phylogenetic trees"
} | null | null | null | null | true | null | 475 | null | Default | null | null |
null | {
"abstract": " Variational Bayesian neural nets combine the flexibility of deep learning\nwith Bayesian uncertainty estimation. Unfortunately, there is a tradeoff\nbetween cheap but simple variational families (e.g.~fully factorized) or\nexpensive and complicated inference procedures. We show that natural gradient\nascent with adaptive weight noise implicitly fits a variational posterior to\nmaximize the evidence lower bound (ELBO). This insight allows us to train\nfull-covariance, fully factorized, or matrix-variate Gaussian variational\nposteriors using noisy versions of natural gradient, Adam, and K-FAC,\nrespectively, making it possible to scale up to modern-size ConvNets. On\nstandard regression benchmarks, our noisy K-FAC algorithm makes better\npredictions and matches Hamiltonian Monte Carlo's predictive variances better\nthan existing methods. Its improved uncertainty estimates lead to more\nefficient exploration in active learning, and intrinsic motivation for\nreinforcement learning.\n",
"title": "Noisy Natural Gradient as Variational Inference"
} | null | null | [
"Computer Science",
"Statistics"
]
| null | true | null | 476 | null | Validated | null | null |
null | {
"abstract": " We define rules for cellular automata played on quasiperiodic tilings of the\nplane arising from the multigrid method in such a way that these cellular\nautomata are isomorphic to Conway's Game of Life. Although these tilings are\nnonperiodic, determining the next state of each tile is a local computation,\nrequiring only knowledge of the local structure of the tiling and the states of\nfinitely many nearby tiles. As an example, we show a version of a \"glider\"\nmoving through a region of a Penrose tiling. This constitutes a potential\ntheoretical framework for a method of executing computations in\nnon-periodically structured substrates such as quasicrystals.\n",
"title": "A Game of Life on Penrose tilings"
} | null | null | null | null | true | null | 477 | null | Default | null | null |
null | {
"abstract": " In the present work, we explore the existence, stability and dynamics of\nsingle and multiple vortex ring states that can arise in Bose-Einstein\ncondensates. Earlier works have illustrated the bifurcation of such states, in\nthe vicinity of the linear limit, for isotropic or anisotropic\nthree-dimensional harmonic traps. Here, we extend these states to the regime of\nlarge chemical potentials, the so-called Thomas-Fermi limit, and explore their\nproperties such as equilibrium radii and inter-ring distance, for multi-ring\nstates, as well as their vibrational spectra and possible instabilities. In\nthis limit, both the existence and stability characteristics can be partially\ntraced to a particle picture that considers the rings as individual particles\noscillating within the trap and interacting pairwise with one another. Finally,\nwe examine some representative instability scenarios of the multi-ring dynamics\nincluding breakup and reconnections, as well as the transient formation of\nvortex lines.\n",
"title": "Single and Multiple Vortex Rings in Three-Dimensional Bose-Einstein Condensates: Existence, Stability and Dynamics"
} | null | null | null | null | true | null | 478 | null | Default | null | null |
null | {
"abstract": " For a class of partially observed diffusions, sufficient conditions are given\nfor the map from initial condition of the signal to filtering distribution to\nbe contractive with respect to Wasserstein distances, with rate which has no\ndependence on the dimension of the state-space and is stable under tensor\nproducts of the model. The main assumptions are that the signal has affine\ndrift and constant diffusion coefficient, and that the likelihood functions are\nlog-concave. Contraction estimates are obtained from an $h$-process\nrepresentation of the transition probabilities of the signal reweighted so as\nto condition on the observations.\n",
"title": "Dimension-free Wasserstein contraction of nonlinear filters"
} | null | null | null | null | true | null | 479 | null | Default | null | null |
null | {
"abstract": " We study the motion of an electron bubble in the zero temperature limit where\nneither phonons nor rotons provide a significant contribution to the drag\nexerted on an ion moving within the superfluid. By using the Gross-Clark model,\nin which a Gross-Pitaevskii equation for the superfluid wavefunction is coupled\nto a Schrödinger equation for the electron wavefunction, we study how\nvortex nucleation affects the measured drift velocity of the ion. We use\nparameters that give realistic values of the ratio of the radius of the bubble\nwith respect to the healing length in superfluid $^4$He at a pressure of one\nbar. By performing fully 3D spatio-temporal simulations of the superfluid\ncoupled to an electron, that is modelled within an adiabatic approximation and\nmoving under the influence of an applied electric field, we are able to recover\nthe key dynamics of the ion-vortex interactions that arise and the subsequent\nion-vortex complexes that can form. Using the numerically computed drift\nvelocity of the ion as a function of the applied electric field, we determine\nthe vortex-nucleation limited mobility of the ion to recover values in\nreasonable agreement with measured data.\n",
"title": "Vortex Nucleation Limited Mobility of Free Electron Bubbles in the Gross-Pitaevskii Model of a Superfluid"
} | null | null | null | null | true | null | 480 | null | Default | null | null |
null | {
"abstract": " We present new JVLA multi-frequency measurements of a set of stars in\ntransition from the post-AGB to the Planetary Nebula phase monitored in the\nradio range over several years. Clear variability is found for five sources.\nTheir light curves show increasing and decreasing patterns. New radio\nobservations at high angular resolution are also presented for two sources.\nAmong these is IRAS 18062+2410, whose radio structure is compared to\nnear-infrared images available in the literature. With these new maps, we can\nestimate inner and outer radii of 0.03$\"$ and 0.08$\"$ for the ionised shell, an\nionised mass of $3.2\\times10^{-4}$ M$_\\odot$, and a density at the inner radius\nof $7.7\\times 10^{-5}$ cm$^{-3}$, obtained by modelling the radio shell with\nthe new morphological constraints. The combination of multi-frequency data and,\nwhere available, spectral-index maps leads to the detection of spectral indices\nnot due to thermal emission, contrary to what one would expect in planetary\nnebulae. Our results allow us to hypothesise the existence of a link between\nradio variability and non-thermal emission mechanisms in the nebulae. This link\nseems to hold for IRAS 22568+6141 and may generally hold for those nebulae\nwhere the radio flux decreases over time.\n",
"title": "Radio variability and non-thermal components in stars evolving toward planetary nebulae"
} | null | null | null | null | true | null | 481 | null | Default | null | null |
null | {
"abstract": " We develop an on-line monitoring procedure to detect a change in a large\napproximate factor model. Our statistics are based on a well-known property of\nthe $% \\left( r+1\\right) $-th eigenvalue of the sample covariance matrix of the\ndata (having defined $r$ as the number of common factors): whilst under the\nnull the $\\left( r+1\\right) $-th eigenvalue is bounded, under the alternative\nof a change (either in the loadings, or in the number of factors itself) it\nbecomes spiked. Given that the sample eigenvalue cannot be estimated\nconsistently under the null, we regularise the problem by randomising the test\nstatistic in conjunction with sample conditioning, obtaining a sequence of\n\\textit{i.i.d.}, asymptotically chi-square statistics which are then employed\nto build the monitoring scheme. Numerical evidence shows that our procedure\nworks very well in finite samples, with a very small probability of false\ndetections and tight detection times in presence of a genuine change-point.\n",
"title": "Sequential testing for structural stability in approximate factor models"
} | null | null | [
"Statistics"
]
| null | true | null | 482 | null | Validated | null | null |
null | {
"abstract": " A susceptibility propagation that is constructed by combining a belief\npropagation and a linear response method is used for approximate computation\nfor Markov random fields. Herein, we formulate a new, improved susceptibility\npropagation by using the concept of a diagonal matching method that is based on\nmean-field approaches to inverse Ising problems. The proposed susceptibility\npropagation is robust for various network structures, and it is reduced to the\nordinary susceptibility propagation and to the adaptive\nThouless-Anderson-Palmer equation in special cases.\n",
"title": "Susceptibility Propagation by Using Diagonal Consistency"
} | null | null | null | null | true | null | 483 | null | Default | null | null |
null | {
"abstract": " This paper analyzes the downlink performance of ultra-dense networks with\nelevated base stations (BSs). We consider a general dual-slope pathloss model\nwith distance-dependent probability of line-of-sight (LOS) transmission between\nBSs and receivers. Specifically, we consider the scenario where each link may\nbe obstructed by randomly placed buildings. Using tools from stochastic\ngeometry, we show that both coverage probability and area spectral efficiency\ndecay to zero as the BS density grows large. Interestingly, we show that the BS\nheight alone has a detrimental effect on the system performance even when the\nstandard single-slope pathloss model is adopted.\n",
"title": "Performance Analysis of Ultra-Dense Networks with Elevated Base Stations"
} | null | null | [
"Computer Science"
]
| null | true | null | 484 | null | Validated | null | null |
null | {
"abstract": " We demonstrate the first application of deep reinforcement learning to\nautonomous driving. From randomly initialised parameters, our model is able to\nlearn a policy for lane following in a handful of training episodes using a\nsingle monocular image as input. We provide a general and easy to obtain\nreward: the distance travelled by the vehicle without the safety driver taking\ncontrol. We use a continuous, model-free deep reinforcement learning algorithm,\nwith all exploration and optimisation performed on-vehicle. This demonstrates a\nnew framework for autonomous driving which moves away from reliance on defined\nlogical rules, mapping, and direct supervision. We discuss the challenges and\nopportunities to scale this approach to a broader range of autonomous driving\ntasks.\n",
"title": "Learning to Drive in a Day"
} | null | null | [
"Computer Science",
"Statistics"
]
| null | true | null | 485 | null | Validated | null | null |
null | {
"abstract": " Strong-coupling of monolayer metal dichalcogenide semiconductors with light\noffers encouraging prospects for realistic exciton devices at room temperature.\nHowever, the nature of this coupling depends extremely sensitively on the\noptical confinement and the orientation of electronic dipoles and fields. Here,\nwe show how plasmon strong coupling can be achieved in compact robust\neasily-assembled gold nano-gap resonators at room temperature. We prove that\nstrong coupling is impossible with monolayers due to the large exciton\ncoherence size, but resolve clear anti-crossings for 8 layer devices with Rabi\nsplittings exceeding 135 meV. We show that such structures improve on prospects\nfor nonlinear exciton functionalities by at least 10^4, while retaining quantum\nefficiencies above 50%.\n",
"title": "Strong-coupling of WSe2 in ultra-compact plasmonic nanocavities at room temperature"
} | null | null | null | null | true | null | 486 | null | Default | null | null |
null | {
"abstract": " Positioning data offer a remarkable source of information to analyze crowds\nurban dynamics. However, discovering urban activity patterns from the emergent\nbehavior of crowds involves complex system modeling. An alternative approach is\nto adopt computational techniques belonging to the emergent paradigm, which\nenables self-organization of data and allows adaptive analysis. Specifically,\nour approach is based on stigmergy. By using stigmergy each sample position is\nassociated with a digital pheromone deposit, which progressively evaporates and\naggregates with other deposits according to their spatiotemporal proximity.\nBased on this principle, we exploit positioning data to identify high density\nareas (hotspots) and characterize their activity over time. This\ncharacterization allows the comparison of dynamics occurring in different days,\nproviding a similarity measure exploitable by clustering techniques. Thus, we\ncluster days according to their activity behavior, discovering unexpected urban\nactivity patterns. As a case study, we analyze taxi traces in New York City\nduring 2015.\n",
"title": "Stigmergy-based modeling to discover urban activity patterns from positioning data"
} | null | null | [
"Computer Science",
"Physics"
]
| null | true | null | 487 | null | Validated | null | null |
null | {
"abstract": " BiHom-Lie Colour algebra is a generalized Hom-Lie Colour algebra endowed with\ntwo commuting multiplicative linear maps. The main purpose of this paper is to\ndefine representations and a cohomology of BiHom-Lie colour algebras and to\nstudy some key constructions and properties.\nMoreover, we discuss $\\alpha^{k}\\beta^l$-generalized derivations,\n$\\alpha^{k}\\beta^l$-quasi-derivations and $\\alpha^{k}\\beta^l$-quasi-centroid.\nWe provide some properties and their relationships with BiHom-Jordan colour\nalgebra.\n",
"title": "BiHom-Lie colour algebras structures"
} | null | null | null | null | true | null | 488 | null | Default | null | null |
null | {
"abstract": " We consider the problem related to clustering of gamma-ray bursts (from\n\"BATSE\" catalogue) through kernel principal component analysis in which our\nproposed kernel outperforms results of other competent kernels in terms of\nclustering accuracy and we obtain three physically interpretable groups of\ngamma-ray bursts. The effectivity of the suggested kernel in combination with\nkernel principal component analysis in revealing natural clusters in noisy and\nnonlinear data while reducing the dimension of the data is also explored in two\nsimulated data sets.\n",
"title": "Clustering of Gamma-Ray bursts through kernel principal component analysis"
} | null | null | null | null | true | null | 489 | null | Default | null | null |
null | {
"abstract": " Baker, Harman, and Pintz showed that a weak form of the Prime Number Theorem\nholds in intervals of the form $[x-x^{0.525},x]$ for large $x$. In this paper,\nwe extend a result of Maynard and Tao concerning small gaps between primes to\nintervals of this length. More precisely, we prove that for any $\\delta\\in\n[0.525,1]$ there exist positive integers $k,d$ such that for sufficiently large\n$x$, the interval $[x-x^\\delta,x]$ contains $\\gg_{k} \\frac{x^\\delta}{(\\log\nx)^k}$ pairs of consecutive primes differing by at most $d$. This confirms a\nspeculation of Maynard that results on small gaps between primes can be refined\nto the setting of short intervals of this length.\n",
"title": "Bounded gaps between primes in short intervals"
} | null | null | null | null | true | null | 490 | null | Default | null | null |
null | {
"abstract": " Improved Phantom cell is a new scenario which has been introduced recently to\nenhance the capacity of Heterogeneous Networks (HetNets). The main trait of\nthis scenario is that, besides maximizing the total network capacity in both\nindoor and outdoor environments, it claims to reduce the handover number\ncompared to the conventional scenarios. In this paper, by a comprehensive\nreview of the Improved Phantom cells structure, an appropriate algorithm will\nbe introduced for the handover procedure of this scenario. To reduce the number\nof handover in the proposed algorithm, various parameters such as the received\nSignal to Interference plus Noise Ratio (SINR) at the user equipment (UE),\nusers access conditions to the phantom cells, and users staying time in the\ntarget cell based on its velocity, has been considered. Theoretical analyses\nand simulation results show that applying the suggested algorithm the improved\nphantom cell structure has a much better performance than conventional HetNets\nin terms of the number of handover.\n",
"title": "Handover analysis of the Improved Phantom Cells"
} | null | null | null | null | true | null | 491 | null | Default | null | null |
null | {
"abstract": " We address the problem of localisation of objects as bounding boxes in images\nwith weak labels. This weakly supervised object localisation problem has been\ntackled in the past using discriminative models where each object class is\nlocalised independently from other classes. We propose a novel framework based\non Bayesian joint topic modelling. Our framework has three distinctive\nadvantages over previous works: (1) All object classes and image backgrounds\nare modelled jointly together in a single generative model so that \"explaining\naway\" inference can resolve ambiguity and lead to better learning and\nlocalisation. (2) The Bayesian formulation of the model enables easy\nintegration of prior knowledge about object appearance to compensate for\nlimited supervision. (3) Our model can be learned with a mixture of weakly\nlabelled and unlabelled data, allowing the large volume of unlabelled images on\nthe Internet to be exploited for learning. Extensive experiments on the\nchallenging VOC dataset demonstrate that our approach outperforms the\nstate-of-the-art competitors.\n",
"title": "Bayesian Joint Topic Modelling for Weakly Supervised Object Localisation"
} | null | null | null | null | true | null | 492 | null | Default | null | null |
null | {
"abstract": " All people have to make risky decisions in everyday life. And we do not know\nhow true they are. But is it possible to mathematically assess the correctness\nof our choice? This article discusses the model of decision making under risk\non the example of project management. This is a game with two players, one of\nwhich is Investor, and the other is the Project Manager. Each player makes a\nrisky decision for himself, based on his past experience. With the help of a\nmathematical model, the players form a level of confidence, depending on who\nthe player accepts the strategy or does not accept. The project manager\nassesses the costs and compares them with the level of confidence. An investor\nevaluates past results. Also visit the case where the strategy of the player\naccepts the part.\n",
"title": "Psychological model of the investor and manager behavior in risk"
} | null | null | null | null | true | null | 493 | null | Default | null | null |
null | {
"abstract": " Modeling the interior of exoplanets is essential to go further than the\nconclusions provided by mean density measurements. In addition to the still\nlimited precision on the planets' fundamental parameters, models are limited by\nthe existence of degeneracies on their compositions. Here we present a model of\ninternal structure dedicated to the study of solid planets up to ~10 Earth\nmasses, i.e. Super-Earths. When the measurement is available, the assumption\nthat the bulk Fe/Si ratio of a planet is similar to that of its host star\nallows us to significantly reduce the existing degeneracy and more precisely\nconstrain the planet's composition. Based on our model, we provide an update of\nthe mass-radius relationships used to provide a first estimate of a planet's\ncomposition from density measurements. Our model is also applied to the cases\nof two well-known exoplanets, CoRoT-7b and Kepler-10b, using their recently\nupdated parameters. The core mass fractions of CoRoT-7b and Kepler-10b are\nfound to lie within the 10-37% and 10-33% ranges, respectively, allowing both\nplanets to be compatible with an Earth-like composition. We also extend the\nrecent study of Proxima Centauri b, and show that its radius may reach 1.94\nEarth radii in the case of a 5 Earth masses planet, as there is a 96.7%\nprobability that the real mass of Proxima Centauri b is below this value.\n",
"title": "Constraints on Super-Earths Interiors from Stellar Abundances"
} | null | null | null | null | true | null | 494 | null | Default | null | null |
null | {
"abstract": " In this paper we discuss the characteristics and operation of Astro Space\nCenter (ASC) software FX correlator that is an important component of\nspace-ground interferometer for Radioastron project. This project performs\njoint observations of compact radio sources using 10 meter space radio\ntelescope (SRT) together with ground radio telescopes at 92, 18, 6 and 1.3 cm\nwavelengths. In this paper we describe the main features of space-ground VLBI\ndata processing of Radioastron project using ASC correlator. Quality of\nimplemented fringe search procedure provides positive results without\nsignificant losses in correlated amplitude. ASC Correlator has a computational\npower close to real time operation. The correlator has a number of processing\nmodes: \"Continuum\", \"Spectral Line\", \"Pulsars\", \"Giant Pulses\",\"Coherent\".\nSpecial attention is paid to peculiarities of Radioastron space-ground VLBI\ndata processing. The algorithms of time delay and delay rate calculation are\nalso discussed, which is a matter of principle for data correlation of\nspace-ground interferometers. During 5 years of Radioastron space radio\ntelescope (SRT) successful operation, ASC correlator showed high potential of\nsatisfying steady growing needs of current and future ground and space VLBI\nscience. Results of ASC software correlator operation are demonstrated.\n",
"title": "Software correlator for Radioastron mission"
} | null | null | null | null | true | null | 495 | null | Default | null | null |
null | {
"abstract": " Schoof's classic algorithm allows point-counting for elliptic curves over\nfinite fields in polynomial time. This algorithm was subsequently improved by\nAtkin, using factorizations of modular polynomials, and by Elkies, using a\ntheory of explicit isogenies. Moving to Jacobians of genus-2 curves, the\ncurrent state of the art for point counting is a generalization of Schoof's\nalgorithm. While we are currently missing the tools we need to generalize\nElkies' methods to genus 2, recently Martindale and Milio have computed\nanalogues of modular polynomials for genus-2 curves whose Jacobians have real\nmultiplication by maximal orders of small discriminant. In this article, we\nprove Atkin-style results for genus-2 Jacobians with real multiplication by\nmaximal orders, with a view to using these new modular polynomials to improve\nthe practicality of point-counting algorithms for these curves.\n",
"title": "Isogenies for point counting on genus two hyperelliptic curves with maximal real multiplication"
} | null | null | null | null | true | null | 496 | null | Default | null | null |
null | {
"abstract": " Let $L/K$ be a tame and Galois extension of number fields with group $G$. It\nis well-known that any ambiguous ideal in $L$ is locally free over\n$\\mathcal{O}_KG$ (of rank one), and so it defines a class in the locally free\nclass group of $\\mathcal{O}_KG$, where $\\mathcal{O}_K$ denotes the ring of\nintegers of $K$. In this paper, we shall study the relationship among the\nclasses arising from the ring of integers $\\mathcal{O}_L$ of $L$, the inverse\ndifferent $\\mathfrak{D}_{L/K}^{-1}$ of $L/K$, and the square root of the\ninverse different $A_{L/K}$ of $L/K$ (if it exists), in the case that $G$ is\nabelian. They are naturally related because $A_{L/K}^2 =\n\\mathfrak{D}_{L/K}^{-1} = \\mathcal{O}_L^*$, and $A_{L/K}$ is special because\n$A_{L/K} = A_{L/K}^*$, where $*$ denotes dual with respect to the trace of\n$L/K$.\n",
"title": "On the self-duality of rings of integers in tame and abelian extensions"
} | null | null | null | null | true | null | 497 | null | Default | null | null |
null | {
"abstract": " Transformative AI technologies have the potential to reshape critical aspects\nof society in the near future. However, in order to properly prepare policy\ninitiatives for the arrival of such technologies accurate forecasts and\ntimelines are necessary. A survey was administered to attendees of three AI\nconferences during the summer of 2018 (ICML, IJCAI and the HLAI conference).\nThe survey included questions for estimating AI capabilities over the next\ndecade, questions for forecasting five scenarios of transformative AI and\nquestions concerning the impact of computational resources in AI research.\nRespondents indicated a median of 21.5% of human tasks (i.e., all tasks that\nhumans are currently paid to do) can be feasibly automated now, and that this\nfigure would rise to 40% in 5 years and 60% in 10 years. Median forecasts\nindicated a 50% probability of AI systems being capable of automating 90% of\ncurrent human tasks in 25 years and 99% of current human tasks in 50 years. The\nconference of attendance was found to have a statistically significant impact\non all forecasts, with attendees of HLAI providing more optimistic timelines\nwith less uncertainty. These findings suggest that AI experts expect major\nadvances in AI technology to continue over the next decade to a degree that\nwill likely have profound transformative impacts on society.\n",
"title": "Forecasting Transformative AI: An Expert Survey"
} | null | null | null | null | true | null | 498 | null | Default | null | null |
null | {
"abstract": " Let $G,H$ be groups, $\\phi: G \\rightarrow H$ a group morphism, and $A$ a\n$G$-graded algebra. The morphism $\\phi$ induces an $H$-grading on $A$, and on\nany $G$-graded $A$-module, which thus becomes an $H$-graded $A$-module. Given\nan injective $G$-graded $A$-module, we give bounds for its injective dimension\nwhen seen as $H$-graded $A$-module. Following ideas by Van den Bergh, we give\nan application of our results to the stability of dualizing complexes through\nchange of grading.\n",
"title": "Change of grading, injective dimension and dualizing complexes"
} | null | null | [
"Mathematics"
]
| null | true | null | 499 | null | Validated | null | null |
null | {
"abstract": " A matrix is said to possess the Restricted Isometry Property (RIP) if it acts\nas an approximate isometry when restricted to sparse vectors. Previous work has\nshown it to be NP-hard to determine whether a matrix possess this property, but\nonly in a narrow range of parameters. In this work, we show that it is NP-hard\nto make this determination for any accuracy parameter, even when we restrict\nourselves to instances which are either RIP or far from being RIP. This result\nimplies that it is NP-hard to approximate the range of parameters for which a\nmatrix possesses the Restricted Isometry Property with accuracy better than\nsome constant. Ours is the first work to prove such a claim without any\nadditional assumptions.\n",
"title": "Approximately certifying the restricted isometry property is hard"
} | null | null | null | null | true | null | 500 | null | Default | null | null |
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