cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Improving Maritime Traffic Emission Estimations on Missing Data with CRBMs
Creators: name: Gutierrez-Torre, Alberto
name: Berral, Josep Ll.
name: Buchaca, David
name: Guevara, Marc
name: Soret, Albert
name: Carrera, David
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computers and Society (cs.CY)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Machine Learning (cs.LG)
subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences
subject: J.2

description: Maritime traffic emissions are a major concern to governments as they heavily impact the Air Quality in coastal cities. Ships use the Automatic Identification System (AIS) to continuously report position and speed among other features, and therefore this data is suitable to be used to estimate emissions, if it is combined with engine data. However, important ship features are often inaccurate or missing. State-of-the-art complex systems, like CALIOPE at the Barcelona Supercomputing Center, are used to model Air Quality. These systems can benefit from AIS based emission models as they are very precise in positioning the pollution. Unfortunately, these models are sensitive to missing or corrupted data, and therefore they need data curation techniques to significantly improve the estimation accuracy. In this work, we propose a methodology for treating ship data using Conditional Restricted Boltzmann Machines (CRBMs) plus machine learning methods to improve the quality of data passed to emission models. Results show that we can improve the default methods proposed to cover missing data. In our results, we observed that using our method the models boosted their accuracy to detect otherwise undetectable emissions. In particular, we used a real data-set of AIS data, provided by the Spanish Port Authority, to estimate that thanks to our method, the model was able to detect 45% of additional emissions, of additional emissions, representing 152 tonnes of pollutants per week in Barcelona and propose new features that may enhance emission modeling.
description: 12 pages, 7 figures. Postprint accepted manuscript, find the full version at Engineering Applications of Artificial Intelligence (https://doi.org/10.1016/j.engappai.2020.103793)
A power-efficient integrated lithium niobate electro-optic comb generator
Creators: name: Zhang, Ke
name: Sun, Wenzhao
name: Chen, Yikun
name: Feng, Hanke
name: Zhang, Yiwen
name: Chen, Zhaoxi
name: Wang, Cheng
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Integrated electro-optic (EO) frequency combs are essential components for future applications in optical communications, light detection and ranging, optical computation, sensing and spectroscopy. To date, broadband on-chip EO combs are typically generated in high-quality-factor micro-resonators, while the more straightforward and flexible non-resonant method, usually using single or cascaded EO phase modulators, often requires high driving power to realize a reasonably strong modulation index. Here, we show that the phase modulation efficiency of an integrated lithium niobate modulator could be dramatically enhanced by passing optical signals through the modulation electrodes for a total of 4 round trips, via multiple low-loss TE0/TE1 mode multiplexers and waveguide crossings, reducing electrical power consumption by more than one order of magnitude. Using devices fabricated from a wafer-scale stepper lithography process, we demonstrate a broadband optical frequency comb featuring 47 comb lines at a 25-GHz repetition rate, using a moderate RF driving power of 28 dBm (0.63 W). Leveraging the excellent tunability in repetition rate and operation wavelength, our power-efficient EO comb generator could serve as a compact low-cost solution for future high-speed data transmission, sensing and spectroscopy, as well as classical and quantum optical computation systems.
description: 9 pages, 4 fingures
Antihyperalgesic effect of gabapentin, quercetin and sigma-1 antagonist in a model of neuropathic pain in rats
Creators: name: Espinosa-Juarez, Josue
name: Osmar Jaramilo-Morales
name: Corona-Ramos, Janette
name: Lopez-Muñoz, Francisco
Publisher: name: F1000Research
Year: 2015

description: Neuropathic pain is produced by injury that affect the somato-sensorial system. The treatment is performed according to the etiology, the most used drugs are neuromodulators, however exist others that may be potentially useful. The aim of this study was to evaluate the efficacy and potency of 3 different drugs in the antihyperalgesic effect in a model of neuropathic pain. In order to evaluate the effect of gabapentin, quercetin and BD-1063 (sigma-1 receptor antagonist), the antihyperalgesic effects was determined after single-doses, using the von frey test in a rat model of neuropathic pain (Benett model). The time-curse analysis shows that Gabapentin (100 mg/kg) reached its maximum effect at 60 min after the treatment, producing an anti-hyperalgesic effect of 91.25 ± 6.70 % whereas Quercetin (177 mg/kg) and BD-1063 (56.2 mg/kg) produced their maximum effect antihyperalgesic at 90 min with 76.67 ± 6.15 % and 73.33 ± 8.02 % respectively. This antihyperalgesic effect remained during 180 min of observation. Analyzing dose-response curves to the areas under the curves, Gabapentin showed greater efficiency and quercetin with BD-1063 presented equally effective. For its part regarding the analysis of pharmacological potency, we compare the ED50, the order of potency from highest to lowest was Gabapentia> Bd-1063> Quercetin. These results suggest that although there are other drugs that may be useful for the treatment of neuropathic pain, gabapentin has greater efficacy and potency at least in the anti-hyperalgesic effect, so it remains one of the drugs of first choice and reference to evaluate new drugs.
Integral field spectroscopy of planetary nebulae: mapping the line diagnostics and hydrogen-poor zones with VLT FLAMES
Creators: name: Tsamis, Y. G.
name: Walsh, J. R.
name: Péquignot, D.
name: Barlow, M. J.
name: Danziger, I. J.
name: Liu, X. -W.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: (Abridged) Results from the first dedicated study of Galactic PNe by means of optical integral field spectroscopy with the VLT FLAMES Argus IFU are presented. Three typical Galactic-disk PNe have been mapped with the 11.5''x7.2'' Argus array: two dimensional spectral maps of NGC 5882, 6153 and 7009 with 297 spatial pixels per target were obtained at sub-arcsec resolutions and 297 spectra per target were obtained in the 396.4-507.8 nm range. Spatially resolved maps of emission lines and of nebular physical properties were produced. The abundances of helium and of doubly ionized carbon and oxygen were derived from optical recombination lines (ORLs), while those of O^2+ were also derived from the collisionally excited lines (CELs). The abundance discrepancy problem was investigated by mapping the ratio of ORL/CEL abundances for O^2+ (the abundance discrepancy factor; ADF) across the face of the PNe. The ADF varies between targets and also with position within the targets attaining values of ~40 in the case of NGC 6153. Correlations of the ADF with geometric distance from the nucleus, as well as with [O III] electron temperature, plasma ionization state and other physical properties are established. Very small values of the temperature fluctuation parameter in the plane of the sky are found in all cases. It is argued that these results provide further evidence for the existence in typical PNe of a distinct nebular component consisting of hydrogen-deficient plasma. The zones containing this posited component appear as undulations in the C II and C II ORL abundance diagnostics of about 2 spatial pixels across; any associated structures should have physical sizes of less than ~1000 astronomical units. We propose that circumstellar disks, Abell 30-type knots, or Helix-type cometary globules may be involved.
description: 27 pages, 18 figures (the resolution of some figures has been reduced); Accepted for publication in MNRAS
Crossover from Fermi Arc to Full Fermi Surface
Creators: name: Zhang, Jia-Xin
name: Weng, Zheng-Yu
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The Fermi surface as a contour of the gapless quasiparticle excitation in momentum space is studied based on a mean-field theory of the doped Mott insulator, where the underlying pseudogap phase is characterized by a two-component resonating-valence-bond (RVB) order that vanishes in the overdoping at $δ>δ^*$. Here the quasiparticle emerges as a ``collective'' mode and a Fermi arc is naturally present in the pseudogap regime, while a full Fermi surface is recovered at $δ>δ^*$. The area enclosed by the gapless quasiparticle contour still satisfies the Luttinger volume in both cases, and the ``Fermi arc'' at $δ<δ^*$ is actually due to a significant reduction of the spectral weight caused by a quasiparticle fractionalization in the antinodal region. The endpoints of the Fermi arcs exhibit enhanced density of states or ``hotspots'', which can further give rise to a charge-density-wave-like quasiparticle interference pattern. At the critical doping $δ^*$, the fractionalized spin excitations become gapless and incoherent which is signaled by a divergent specific heat. At $δ>δ^*$, the quasiparticle excitation restores the coherence over the full Fermi surface, but the fractionalization still persists at a higher energy/temperature which may be responsible for a strange metal behavior. Different mechanisms for the Fermi arc and experimental comparisons are briefly discussed.
description: 20 pages, 13 figures
The behavior of $f(R)$ gravity in the solar system, galaxies and clusters
Creators: name: Zhang, Pengjie
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: For cosmologically interesting $f(R)$ gravity models, we derive the complete set of the linearized field equations in the Newtonian gauge, under environments of the solar system, galaxies and clusters respectively. Based on these equations, we confirmed previous $γ=1/2$ solution in the solar system. However, $f(R)$ gravity models can be strongly environment-dependent and the high density (comparing to the cosmological mean) solar system environment can excite a viable $γ=1$ solution for some $f(R)$ gravity models. Although for $f(R)\propto -1/R$, it is not the case; for $f(R)\propto -\exp(-R/λ_2H_0^2)$, such $γ=1$ solution does exist. This solution is virtually indistinguishable from that in general relativity (GR) and the value of the associated curvature approaches the GR limit, which is much higher than value in the $γ=1/2$ solution. We show that for some forms of $f(R)$ gravity, this solution is physically stable in the solar system and can smoothly connect to the surface of the Sun. The derived field equations can be applied directly to gravitational lensing of galaxies and clusters. We find that, despite significant difference in the environments of galaxies and clusters comparing to that of the solar system, gravitational lensing of galaxies and clusters can be virtually identical to that in GR, for some forms of $f(R)$ gravity. Fortunately, galaxy rotation curve and intra-cluster gas pressure profile may contain valuable information to distinguish these $f(R)$ gravity models from GR.
description: Significantly revised. 6 pages. Accepted to PRD
From high-$T_c$ to low-$T_c$: Multi-orbital effects in transition metal oxides
Creators: name: Klett, Michael
name: Schwemmer, Tilman
name: Wolf, Sebastian
name: Wu, Xianxin
name: Riegler, David
name: Dittmaier, Andreas
name: Di Sante, Domenico
name: Li, Gang
name: Hanke, Werner
name: Rachel, Stephan
name: Thomale, Ronny
Publisher: name: arXiv
Year: 2021
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Despite the structural resemblance of certain cuprate and nickelate parent compounds there is a striking spread of $T_c$ among such transition metal oxide superconductors. We adopt a minimal two-orbital $e_g$ model which covers cuprates and nickelate heterostructures in different parametric limits, and analyse its superconducting instabilities. The joint consideration of interactions, doping, Fermiology, and in particular the $e_g$ orbital splitting allows us to explain the strongly differing pairing propensities in cuprate and nickelate superconductors.
Stability of a Noncommutative Jackiw-Teitelboim Gravity
Creators: name: Vassilevich, D. V.
name: Fresneda, R.
name: Gitman, D. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We start with a noncommutative version of the Jackiw-Teitelboim gravity in two dimensions which has a linear potential for the dilaton fields. We study whether it is possible to deform this model by adding quadratic terms to the potential but preserving the number of gauge symmetries. We find that no such deformation exists (provided one does not twist the gauge symmetries).
description: Added reference
On the identifiability of Bayesian factor analytic models
Creators: name: Papastamoulis, Panagiotis
name: Ntzoufras, Ioannis
Publisher: name: arXiv
Year: 2020
Subjects: subject: Methodology (stat.ME)
subject: Computation (stat.CO)
subject: FOS: Computer and information sciences

description: A well known identifiability issue in factor analytic models is the invariance with respect to orthogonal transformations. This problem burdens the inference under a Bayesian setup, where Markov chain Monte Carlo (MCMC) methods are used to generate samples from the posterior distribution. We introduce a post-processing scheme in order to deal with rotation, sign and permutation invariance of the MCMC sample. The exact version of the contributed algorithm requires to solve $2^q$ assignment problems per (retained) MCMC iteration, where $q$ denotes the number of factors of the fitted model. For large numbers of factors two approximate schemes based on simulated annealing are also discussed. We demonstrate that the proposed method leads to interpretable posterior distributions using synthetic and publicly available data from typical factor analytic models as well as mixtures of factor analyzers. An R package is available online at CRAN web-page.
description: to appear in STCO
Universe driven by the vacuum of scalar field: VFD model
Creators: name: Cherkas, S. L.
name: Kalashnikov, V. L.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: It is shown that in the Vacuum Fluctuations Domination model (VFD), where vacuum fluctuations of scalar fields dominates under matter and radiation throughout the all history of the Universe expansion (arXiv:gr-qc/0604020, arXiv:gr-qc/0610148), acceleration parameter evolves monotonically from the zero to the present day negative value. That is according to this model the Universe has no decelerating past and conventional radiation domination and matter domination epochs are absent. Predictions of accelerating parameter for z~0-2 is compared with that follows from the SN type Ia data.
description: 7 pages, 1 figures
The Anisotropy in the Galaxy Velocity Field Originated from the Gravitational Pancaking Effect
Creators: name: Noh, Yookyung
name: Lee, Jounghun
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We analyze the Millennium run semi-analytic galaxy catalog to explore quantitatively the gravitational pancaking effect on the orientation of galaxy velocity field. We first calculate the probability density distribution of the cosine of the angle between the velocity of a field galaxy and the direction normal to a local pancake plane which is determined using two nearest neighbor field galaxies. A clear signal of alignment is detected for the case that the pancake scale is in the range of $5-8h^{-1}$ Mpc. The tendency of the velocity-pancake alignment is found to still exist when the pancakes are determined using three neighbor galaxies, indicating that it has a spatial coherence. The degree of the velocity-pancake alignment is shown to increase with the velocity magnitude and the local density, while it decreases with the separation distance from the galaxy to the pancake and disappears when the pancake has a filamentary shape. A final conclusion is that our work may provide another clue to understanding the large-scale structure in the universe.
description: accepted by ApJL, new analyses included, discussions improved
ความบาดหมาง ระหว่างมินะโมะโตะ โนะ โยะฌิโตะโมะ กับ มินะโมะโตะ โนะ ทะเมะโตะโมะในนิยายสงครามเรื่อง "โฮเง็นโมะโนะงะตะริ"
Creators: name: กณภัทร รื่นภิรมย์
Publisher: name: สมาคมญี่ปุ่นศึกษาแห่งประเทศไทย
Year: 2020
Subjects: โฮเง็นโมะโนะงะตะริ
พี่น้อง
มินะโมะโตะ
โยะฌิโตะโมะ
ทะเมะโตะโม

description: วารสารเครือข่ายญี่ปุ่นศึกษา, 10, 2, 78-99
Mesonic quasinormal modes of the Sakai-Sugimoto model at high temperature
Creators: name: Evans, Nick
name: Threlfall, Ed
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We examine the mesonic thermal spectrum of the Sakai-Sugimoto model of holographic QCD by finding the quasinormal frequencies of the supergravity dual. If flavour is added using D8 and anti-D8 branes there exist embeddings where the D-brane worldvolume contains a black hole. For these embeddings (the high-temperature phase of the Sakai-Sugimoto model) we determine the quasinormal spectra of scalar and vector mesons arising from the worldvolume DBI action of the D-brane. We stress the importance of a coordinate change that makes the in-falling quasinormal modes regular at the horizon allowing a simple numerical shooting technique. Finally we examine the effect of finite spatial momentum on quasinormal spectra.
description: 7 pages with 6 eps figures, typos corrected
Initializing a Quantum Register from Mott Insulator States in Optical Lattices
Creators: name: Zhang, Chuanwei
name: Scarola, V. W.
name: Sarma, S. Das
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We propose and quantitatively develop two schemes to quickly and accurately generate a stable initial configuration of neutral atoms in optical microtraps by extraction from the Mott insulator state in optical lattices. We show that thousands of atoms may be extracted and stored in the ground states of optical microtrap arrays with one atom per trap in one operational process demonstrating massive scalability. The failure probability during extraction in the first scheme can be made sufficiently small (10^{-4}) to initialize a large scale quantum register with high fidelity. A complementary faster scheme with more extracted atoms but lower fidelity is also developed.
description: 5 pages, 3 figures
On a class of stochastic partial differential equations with multiple invariant measures
Creators: name: Fárkas, Balint
name: Friesen, Martin
name: Rüdiger, Barbara
name: Schroers, Dennis
Publisher: name: arXiv
Year: 2020
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: In this work we investigate the long-time behavior, that is the existence and characterization of invariant measures as well as convergence of transition probabilities, for Markov processes obtained as the unique mild solution to stochastic partial differential equations in a Hilbert space. Contrary to the existing literature where typically uniqueness of invariant measures is studied, we focus on the case where the uniqueness of invariant measures fails to hold. Namely, using a \textit{generalized dissipativity condition} combined with a decomposition of the Hilbert space, we prove the existence of multiple limiting distributions in dependence of the initial state of the process and study the convergence of transition probabilities in the Wasserstein 2-distance. Finally, we show that these results contain Lévy driven Ornstein-Uhlenbeck processes, the Heath-Jarrow-Morton-Musiela equation as well as stochastic partial differential equations with delay as a particular case.
Reconstruction of vertex algebras in even higher dimensions
Creators: name: Bakalov, Bojko N.
name: Nikolov, Nikolay M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Algebra (math.QA)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 17B69 (Primary), 81R10, 81T40 (Secondary)

description: Vertex algebras in higher dimensions correspond to models of quantum field theory with global conformal invariance. Any vertex algebra in dimension D admits a restriction to a vertex algebra in any lower dimension and, in particular, to dimension one. In the case when D is even, we find natural conditions under which the converse passage is possible. These conditions include a unitary action of the conformal Lie algebra with a positive energy, which is given by local endomorphisms and obeys certain integrability properties.
description: 27 pages; v5 changed the title, fixed typos and improved the exposition
Examining spatial heterogeneity of ridesourcing demand determinants with explainable machine learning
Creators: name: Zhang, Xiaojian
name: Yan, Xiang
name: Zhou, Zhengze
name: Xu, Yiming
name: Zhao, Xilei
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: The growing significance of ridesourcing services in recent years suggests a need to examine the key determinants of ridesourcing demand. However, little is known regarding the nonlinear effects and spatial heterogeneity of ridesourcing demand determinants. This study applies an explainable-machine-learning-based analytical framework to identify the key factors that shape ridesourcing demand and to explore their nonlinear associations across various spatial contexts (airport, downtown, and neighborhood). We use the ridesourcing-trip data in Chicago for empirical analysis. The results reveal that the importance of built environment varies across spatial contexts, and it collectively contributes the largest importance in predicting ridesourcing demand for airport trips. Additionally, the nonlinear effects of built environment on ridesourcing demand show strong spatial variations. Ridesourcing demand is usually most responsive to the built environment changes for downtown trips, followed by neighborhood trips and airport trips. These findings offer transportation professionals nuanced insights for managing ridesourcing services.
Dark Matter and Collider Phenomenology of Universal Extra Dimensions
Creators: name: Hooper, Dan
name: Profumo, Stefano
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We review the phenomenology of models with flat, compactified extra dimensions where all of the Standard Model fields are allowed to propagate in the bulk, known as Universal Extra Dimensions (UED). UED make for an interesting TeV-scale physics scenario, featuring a tower of Kaluza-Klein (KK) states approximately degenerate in mass at the scale set by the inverse size of the compactification radius. KK parity, the four-dimensional remnant of momentum conservation in the extra dimensions, implies two basic consequences: (1) contributions to Standard Model observables arise only at loop level, and KK states can only be pair-produced at colliders, and (2) the lightest KK particle (LKP) is stable, providing a suitable particle dark matter candidate. After a theoretical overview on extra dimensional models, and on UED in particular, we introduce the model particle spectrum and the constraints from precision electroweak tests and current colliders data. We then give a detailed overview of the LKP dark matter phenomenology, including the LKP relic abundance, and direct and indirect searches. We then discuss the physics of UED at colliders, with particular emphasis on the signatures predicted for the Large Hadron Collider and at a future Linear Collider, as well as on the problem of discriminating between UED and other TeV-scale new physics scenarios, particularly supersymmetry. We propose a set of reference benchmark models, representative of different viable UED realizations. Finally, we collect in the Appendix all the relevant UED Feynman rules, the scattering cross sections for annihilation and coannihilation processes in the early universe and the production cross section for strongly interacting KK states at hadron colliders.
description: Version to appear on Physics Reports, 114 pages, 40 figures; references and material added
Orbifolds of Lattice Vertex Algebras
Creators: name: Bakalov, Bojko
name: Elsinger, Jason
name: Kac, Victor G.
name: Todorov, Ivan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Algebra (math.QA)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: Primary 17B69, Secondary 81R10

description: To a positive-definite even lattice $Q$, one can associate the lattice vertex algebra $V_Q$, and any automorphism $σ$ of $Q$ lifts to an automorphism of $V_Q$. In this paper, we investigate the orbifold vertex algebra $V_Q^σ$, which consists of the elements of $V_Q$ fixed under $σ$, in the case when $σ$ has prime order. We describe explicitly the irreducible $V_Q^σ$-modules, compute their characters, and determine the modular transformations of characters. As an application, we find the asymptotic and quantum dimensions of all irreducible $V_Q^σ$-modules. We consider in detail the cases when the order of $σ$ is $2$ or $3$, as well as the case of permutation orbifolds.
description: 105 pages
tf.data service: A Case for Disaggregating ML Input Data Processing
Creators: name: Audibert, Andrew
name: Chen, Yang
name: Graur, Dan
name: Klimovic, Ana
name: Simsa, Jiri
name: Thekkath, Chandramohan A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: Machine learning (ML) computations commonly execute on expensive specialized hardware, such as GPUs and TPUs, which provide high FLOPs and performance-per-watt. For cost efficiency, it is essential to keep these accelerators highly utilized. This requires preprocessing input data at the rate at which the accelerators can ingest and perform ML computations on the data. To avoid data stalls, the host CPU and RAM required for input data processing per accelerator core used for ML computations varies across jobs. Hence, the traditional approach of processing input data on ML accelerator hosts with a fixed hardware ratio leads to either under-utilizing the accelerators or the host CPU and RAM. In this paper, we address these concerns by building a disaggregated ML data processing system.
 We present tf.data service, an open-source disaggregated input data processing service built on top of tf.data in TensorFlow. We show that disaggregating data preprocessing has three key advantages for large-scale ML training jobs. First, the service can horizontally scale-out to right-size CPU/RAM host resources for data processing in each job, saving 32x training time and 26x cost, on average. Second, the service can share ephemeral preprocessed data results across jobs, to optimize CPU usage and reduce redundant computations. Finally, the service supports coordinated reads, a technique that avoids stragglers due to different input sizes in distributed training, reducing training time by 2.2x, on average. Our design is inspired by lessons learned from deploying tf.data service in production, including relaxing data visitation guarantees without impacting model accuracy.
Effect of oxygen adsorption and oxidation on the strain state of Pd nanocrystals
Creators: name: Mukherjee, Binayak
name: Flor, Alberto
name: Scardi, Paolo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: X-ray powder diffraction using a synchrotron light source reveals significant modifications to both morphology and strain state in Palladium nanocubes after oxidation. Short-range strain measured by the static component of the Debye-Waller coefficient is observed to be higher in the oxidized nanoparticles; while long-range strain related to the line broadening of the diffraction peaks is seen to decrease. Using multiscale modelling with classical molecular dynamics and density functional theory, we connect the decrease in long-range strain to the increased truncation of the oxidized nanocubes, while the higher short-range strain is shown to be due to surface softening from oxygen adsorption. Different surface disorder on different crystallographic facets lead to opposing trends for oxygen activation on the different exposed surfaces of the truncated nanoparticles.
description: 22 pages, 11 figures
Spin relaxation of "upstream" electrons in quantum wires: Failure of the drift diffusion model
Creators: name: Pramanik, Sandipan
name: Bandyopadhyay, Supriyo
name: Cahay, Marc
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: The classical drift diffusion (DD) model of spin transport treats spin relaxation via an empirical parameter known as the ``spin diffusion length''. According to this model, the ensemble averaged spin of electrons drifting and diffusing in a solid decays exponentially with distance due to spin dephasing interactions. The characteristic length scale associated with this decay is the spin diffusion length. The DD model also predicts that this length is different for ``upstream'' electrons traveling in a decelerating electric field than for ``downstream'' electrons traveling in an accelerating field. However this picture ignores energy quantization in confined systems (e.g. quantum wires) and therefore fails to capture the non-trivial influence of subband structure on spin relaxation. Here we highlight this influence by simulating upstream spin transport in a multi-subband quantum wire, in the presence of D'yakonov-Perel' spin relaxation, using a semi-classical model that accounts for the subband structure rigorously. We find that upstream spin transport has a complex dynamics that defies the simplistic definition of a ``spin diffusion length''. In fact, spin does not decay exponentially or even monotonically with distance, and the drift diffusion picture fails to explain the qualitative behavior, let alone predict quantitative features accurately. Unrelated to spin transport, we also find that upstream electrons undergo a ``population inversion'' as a consequence of the energy dependence of the density of states in a quasi one-dimensional structure.
description: 13 figures. To appear in Phys. Rev. B
Fast differentiable DNA and protein sequence optimization for molecular design
Creators: name: Linder, Johannes
name: Seelig, Georg
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Designing DNA and protein sequences with improved function has the potential to greatly accelerate synthetic biology. Machine learning models that accurately predict biological fitness from sequence are becoming a powerful tool for molecular design. Activation maximization offers a simple design strategy for differentiable models: one-hot coded sequences are first approximated by a continuous representation which is then iteratively optimized with respect to the predictor oracle by gradient ascent. While elegant, this method suffers from vanishing gradients and may cause predictor pathologies leading to poor convergence. Here, we build on a previously proposed straight-through approximation method to optimize through discrete sequence samples. By normalizing nucleotide logits across positions and introducing an adaptive entropy variable, we remove bottlenecks arising from overly large or skewed sampling parameters. The resulting algorithm, which we call Fast SeqProp, achieves up to 100-fold faster convergence compared to previous versions of activation maximization and finds improved fitness optima for many applications. We demonstrate Fast SeqProp by designing DNA and protein sequences for six deep learning predictors, including a protein structure predictor.
description: All code available at http://www.github.com/johli/seqprop; Moved example sequences from Suppl to new Figure 2, Added new benchmark comparison to Section 4.3, Moved some technical comparisons to Suppl, Added new Methods section
Artificial Intelligence and Quantum Cryptography
Creators: name: Radanliev, Petar
Publisher: name: figshare
Year: 2024
Subjects: classificationCode: 460201
subject: Artificial life and complex adaptive systems
classificationCode: 460202
subject: Autonomous agents and multiagent systems
classificationCode: 460203
subject: Evolutionary computation
classificationCode: 460204
subject: Fuzzy computation
classificationCode: 460205
subject: Intelligent robotics
classificationCode: 460207
subject: Modelling and simulation
classificationCode: 460206
subject: Knowledge representation and reasoning
classificationCode: 460208
subject: Natural language processing
classificationCode: 460209
subject: Planning and decision making
classificationCode: 460210
subject: Satisfiability and optimisation
classificationCode: 460211
subject: Speech production
classificationCode: 460212
subject: Speech recognition
classificationCode: 460401
subject: Cryptography
classificationCode: 460402
subject: Data and information privacy
classificationCode: 460403
subject: Data security and protection
classificationCode: 460404
subject: Digital forensics
classificationCode: 460405
subject: Hardware security
classificationCode: 460406
subject: Software and application security
classificationCode: 460407
subject: System and network security
classificationCode: 460499
subject: Cybersecurity and privacy not elsewhere classified

description: The technological advancements made in recent times, particularly in Artificial Intelligence (AI) and Quantum Computing, have brought about significant changes in technology. These advancements have profoundly impacted quantum cryptography, a field where AI methodologies hold tremendous potential to enhance the efficiency and robustness of cryptographic systems. However, the emergence of quantum computers has created a new challenge for existing security algorithms, commonly called the 'quantum threat'. Despite these challenges, there are promising avenues for integrating neural network-based AI in cryptography, which has significant implications for future digital security paradigms. This summary highlights the key themes in the intersection of AI and quantum cryptography, including the potential benefits of AI-driven cryptography, the challenges that need to be addressed, and the prospects of this interdisciplinary research area.
Paying down metadata debt: learning the representation of concepts using topic models
Creators: name: Chen, Jiahao
name: Veloso, Manuela
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Digital Libraries (cs.DL)
subject: Numerical Analysis (math.NA)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: I.2.6; J.1
subject: 65F55, 68T50, 68T01, 15A83

description: We introduce a data management problem called metadata debt, to identify the mapping between data concepts and their logical representations. We describe how this mapping can be learned using semisupervised topic models based on low-rank matrix factorizations that account for missing and noisy labels, coupled with sparsity penalties to improve localization and interpretability. We introduce a gauge transformation approach that allows us to construct explicit associations between topics and concept labels, and thus assign meaning to topics. We also show how to use this topic model for semisupervised learning tasks like extrapolating from known labels, evaluating possible errors in existing labels, and predicting missing features. We show results from this topic model in predicting subject tags on over 25,000 datasets from Kaggle.com, demonstrating the ability to learn semantically meaningful features.
description: 8 pages, 4 figures. Data set available in paper source
Resonantly Enhanced Axion-Photon Regeneration
Creators: name: Sikivie, P.
name: Tanner, D. B.
name: van Bibber, Karl
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We point out that photon regeneration-experiments that search for the axion, or axion-like particles, may be resonantly enhanced by employing matched Fabry-Perot optical cavities encompassing both the axion production and conversion magnetic field regions. Compared to a simple photon regeneration experiment, which uses the laser in a single-pass geometry, this technique can result in a gain in rate of order ${\cal F}^2$, where ${\cal F}$ is the finesse of the cavities. This gain could feasibly be $10^{(10-12)}$, corresponding to an improvement in sensitivity in the axion-photon coupling, $g_{aγγ}$ , of order ${\cal F}^{1/2} \sim 10^{(2.5-3)}$, permitting a practical purely laboratory search to probe axion-photon couplings not previously excluded by stellar evolution limits, or solar axion searches.
description: 4 pages, 2 figures
การออกกลางคันในระดับอุดมศึกษา: ปัญหาที่ต้องเร่งให้ความสนใจและแก้ไข
Creators: name: ชำนาญ ปาณาวงษ์
Publisher: name: งานวิจัยและวิเทศสัมพันธ์  บัณฑิตวิทยาลัย  มหาวิทยาลัยนเรศวร
Year: 2558
Subjects: การออกกลางคัน, การสูญเปล่าทางการศึกษา, อุดมศึกษา, Drop-Out, Education Wastage, Higher Education

description: 2, 8, วารสารการวิจัยเพื่อพัฒนาชุมชน (มนุษยศาสตร์และสังคมศาสตร์)
Over-The-Air Computation in Correlated Channels
Creators: name: Frey, Matthias
name: Bjelakovic, Igor
name: Stanczak, Slawomir
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Theory (cs.IT)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper addresses the problem of Over-The-Air (OTA) computation in wireless networks which has the potential to realize huge efficiency gains for instance in training of distributed ML models. We provide non-asymptotic, theoretical guarantees for OTA computation in fast-fading wireless channels where the fading and noise may be correlated. The distributions of fading and noise are not restricted to Gaussian distributions, but instead are assumed to follow a distribution in the more general sub-gaussian class. Furthermore, our result does not make any assumptions on the distribution of the sources and therefore, it can, e.g., be applied to arbitrarily correlated sources. We illustrate our analysis with numerical evaluations for OTA computation of two example functions in large wireless networks: the arithmetic mean and the Euclidean norm.
description: Extended version can be found at arXiv:2007.02648
Kerr-NUT-de Sitter Curvature in All Dimensions
Creators: name: Hamamoto, Naoki
name: Houri, Tsuyoshi
name: Oota, Takeshi
name: Yasui, Yukinori
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We explicitly calculate the Riemannian curvature of D-dimensional metrics recently discussed by Chen, Lu and Pope. We find that they can be concisely written by using a single function. The Einstein condition which corresponds to the Kerr-NUT-de Sitter metric is clarified for all dimensions. It is shown that the metrics are of type D.
description: 10 pages
Constraints on the nuclear symmetry energy from asymmetric-matter calculations with chiral NN and 3N interactions
Creators: name: Somasundaram, R.
name: Drischler, C.
name: Tews, I.
name: Margueron, J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The nuclear symmetry energy is a key quantity in nuclear (astro)physics. It describes the isospin dependence of the nuclear equation of state (EOS), which is commonly assumed to be almost quadratic. In this work, we confront this standard quadratic expansion of the EOS with explicit asymmetric nuclear-matter calculations based on a set of commonly used Hamiltonians including two- and three-nucleon forces derived from chiral effective field theory. We study, in particular, the importance of non-quadratic contributions to the symmetry energy, including the non-analytic logarithmic term introduced by Kaiser [Phys.~Rev.~C \textbf{91}, 065201 (2015)]. Our results suggest that the quartic contribution to the symmetry energy can be robustly determined from the various Hamiltonians employed, and we obtain 1.00(8) MeV (or 0.55(8) MeV for the potential part) at saturation density, while the logarithmic contribution to the symmetry energy is relatively small and model-dependent. We finally employ the meta-model approach to study the impact of the higher-order contributions on the neutron-star crust-core transition density, and find a small 5\% correction.
description: 23 pages and 12 figures; Supplemental Material: 2 pages
Beyond quantum chaos in emergent dual holography
Creators: name: Kim, Ki-Seok
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Black hole is well known to be a fast scrambler, responsible for physics of quantum chaos in dual holography. Recently, the Euclidean worm hole has been proposed to play a central role in the chaotic behavior of the spectral form factor. Furthermore, this phenomena was reinterpreted based on an effective field theory approach for quantum chaos. Since the graded nonlinear $σ-$model approach can describe not only the Wigner-Dyson level statistics but also its Poisson distribution, it is natural to ask whether the dual holography can touch the Poisson regime beyond the quantum chaos. In this study, we investigate disordered strongly coupled conformal field theories in the large central-charge limit. An idea is to consider a quenched average for metric fluctuations and to take into account the renormalization group flow of the metric-tensor distribution function from the UV to the IR boundary. Here, renormalization effects at a given disorder configuration are described by the conventional dual holography. We uncover that the renormalized distribution function shows a power-law behavior universally, interpreted as an infinite randomness fixed point.
Elasmobranch fisheries: status, assessment and management
Creators: name: Bonfil-Sanders, Ramon
Publisher: name: University of British Columbia
Year: 2009

description: An overview of the situation of elasmobranch fisheries around the world and problems for their assessment and management are presented. Four different studies are carried out, each attacking a particular problem under this general topic. The first, is an in-depth review of recent trends in elasmobranch exploitation and management on a worldwide basis aimed at closing the gap in baseline information about these fisheries on a global scale. In the second study, a deterministic age-structured simulation model is developed to analyse density-dependent changes in fecundity as a response to increased fishing mortality in a hypothetical shark population. The use of the model as an aid in management decision-making is exemplified with a case from a tropical shark fishery. Monte Carlo analysis is used in the third study, to evaluate the Schaefer and Fox surplus production models and the delay-difference model of Deriso-Schnute for the estimation of assessment and management parameters of elasmobranch fisheries. The fishery models are evaluated by comparing their estimates of stock assessment a n d management parameters against the known values of a full age-structured stochastic simulation model of a shark population. Different scenarios of stock recruitment relationship, fishable stock size, spatial behaviour of the sharks, and data quality are used for testing robustness. None of the fishery models performs satisfactorily under situations of density-dependent catchability. When catchability remains constant, the Deriso-Schnute model outperforms the Schaefer or Fox models, both for biomass and management parameter estimation. In the final study, the multispecies shark fishery of Yucatan, Mexico, is used as an example of the problems for elasmobranch stock assessment in the real world. The fishery is analysed by fitting the Schaefer model to catch and cpue data. The results highlight severe deficiencies in the data available for assessment which are characterised by a lack o f contrast in the cpue data. Some alternative management recommendations aimed at improving the data for assessment are given.
On values of the Bessel function for generic representations of finite general linear groups
Creators: name: Zelingher, Elad
Publisher: name: arXiv
Year: 2022
Subjects: subject: Representation Theory (math.RT)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 20C33, 11L05, 11T24

description: We find a recursive expression for the Bessel function of S. I. Gelfand for irreducible generic representations of $\operatorname{GL}_n\left(\mathbb{F}_q\right)$. We show that special values of the Bessel function can be realized as the coefficients of $L$-functions associated with exotic Kloosterman sums, and as traces of exterior powers of Katz's exotic Kloosterman sheaves. As an application, we show that certain polynomials, having special values of the Bessel function as their coefficients, have all of their roots lying on the unit circle. As another application, we show that special values of the Bessel function of the Shintani base change of an irreducible generic representation are related to special values of the Bessel function of the representation through Dickson polynomials.
description: 37 pages. Comments are welcome. v2: This version contains all changes that were made for submission in Advances in Mathematics
B0-B0bar mixing
Creators: name: Schneider, Olivier
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The subject of particle-antiparticle mixing in the neutral B meson systems is reviewed. The formalism of B0-B0bar mixing is recalled and basic Standard Model predictions are given, before experimental issues are discussed and the latest combinations of experimental results on mixing parameters are presented, including those on mixing-induced CP violation, mass differences, and decay-width differences. Finally, time-integrated mixing results are used to improve our knowledge on the fractions of the various b-hadron species produced in Z decays and at high-energy colliders.
description: 14 pages (+ cover), 2 figures, to appear in 2006 edition of the ``Review of Particle Physics'', W.-M. Yao et al. (Particle Data Group), J. Phys. G: Nucl. Part. Phys. 33, 1 (2006)