cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Semi-equivelar toroidal maps and their k-edge covers
Creators: name: Kundu, Arnab
name: Maity, Dipendu
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 52C20, 52B70, 51M20, 57M60

description: If the face\mbox{-}cycles at all the vertices in a map are of same type then the map is called semi\mbox{-}equivelar. A tiling is edge-homogeneous if any two edges with vertices of congruent face-cycles. In general, edge-homogeneous maps on a surface form a bigger class than edge-transitive maps. There are edge-homogeneous toroidal maps which are not edge\mbox{-}transitive. An edge-homogeneous map is called $k$-edge-homogeneous if it contains $k$ number of edge orbits. In particular, if $k=1$ then it is called edge-transitive map. In general, a map is called $k$-edge orbital or $k$-orbital if it contains $k$ number of edge orbits. A map is called minimal if the number of edges is minimal. A surjective mapping $η\colon M \to K$ from a map $M$ to a map $K$ is called a covering if it preserves adjacency and sends vertices, edges, faces of $M$ to vertices, edges, faces of $K$ respectively. Orbani{\' c} et al. and {\v S}ir{á}{\v n} et al. have shown that every edge-homogeneous toroidal map has edge-transitive cover. In this article, we show the bounds of edge orbits of edge-homogeneous toroidal maps. Using these bounds, we show the bounds of edge orbits of non-edge-homogeneous semi-equivelar toroidal maps. We also prove that if a edge-homogeneous map is $k$ edge orbital then it has a finite index $m$-edge orbital minimal cover for $m \le k$. We also show the existence and classification of $n$ sheeted covers of edge-homogeneous toroidal maps for each $n \in \mathbb{N}$. We extend this to non-edge-homogeneous semi-equivelar toroidal maps and prove the same results, i.e., if a non-edge-homogeneous map is $k$ edge orbital then it has a finite index $m$-edge orbital minimal cover (non-edge-homogeneous) for $m \le k$ and then classify them for each sheet.
description: arXiv admin note: substantial text overlap with arXiv:2110.12375
The Richness and Beauty of the Physics of Cosmological Recombination: The Contributions from Helium
Creators: name: Sunyaev, R. A.
name: Chluba, J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The physical ingredients to describe the epoch of cosmological recombination are amazingly simple and well-understood. This fact allows us to take into account a very large variety of processes, still finding potentially measurable consequences. In this contribution we highlight some of the detailed physics that were recently studied in connection with cosmological hydrogen and helium recombination. The impact of these considerations is two-fold: (i) the associated release of photons during this epoch leads to interesting and unique deviations of the Cosmic Microwave Background (CMB) energy spectrum from a perfect blackbody, which, in particular at decimeter wavelength, may become observable in the near future. Despite the fact that the abundance of helium is rather small, it also contributes a sizeable amount of photons to the full recombination spectrum, which, because of differences in the dynamics of the helium recombinations and the non-trivial superposition of all components, lead to additional distinct spectral features. Observing the spectral distortions from the epochs of hydrogen and helium recombination, in principle would provide an additional way to determine some of the key parameters of the Universe (e.g. the specific entropy, the CMB monopole temperature and the pre-stellar abundance of helium), not suffering from limitations set by cosmic variance. Also it permits us to confront our detailed understanding of the recombination process with direct observational evidence. (ii) with the advent of high precision CMB data, e.g. as will be available using the Planck Surveyor or CMBpol, a very accurate theoretical understanding of the ionization history of the Universe becomes necessary for the interpretation of the CMB temperature and polarization anisotropies. (abridged)
description: 16 pages, 11 figures, proceedings of the conference: "A Century of Cosmology: Past, Present and Future"
Towards Self-Regulating AI: Challenges and Opportunities of AI Model Governance in Financial Services
Creators: name: Kurshan, Eren
name: Shen, Hongda
name: Chen, Jiahao
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: General Finance (q-fin.GN)
subject: Applications (stat.AP)
subject: FOS: Computer and information sciences
subject: FOS: Economics and business
subject: I.2.1; J.4
subject: 68T01, 91-02

description: AI systems have found a wide range of application areas in financial services. Their involvement in broader and increasingly critical decisions has escalated the need for compliance and effective model governance. Current governance practices have evolved from more traditional financial applications and modeling frameworks. They often struggle with the fundamental differences in AI characteristics such as uncertainty in the assumptions, and the lack of explicit programming. AI model governance frequently involves complex review flows and relies heavily on manual steps. As a result, it faces serious challenges in effectiveness, cost, complexity, and speed. Furthermore, the unprecedented rate of growth in the AI model complexity raises questions on the sustainability of the current practices. This paper focuses on the challenges of AI model governance in the financial services industry. As a part of the outlook, we present a system-level framework towards increased self-regulation for robustness and compliance. This approach aims to enable potential solution opportunities through increased automation and the integration of monitoring, management, and mitigation capabilities. The proposed framework also provides model governance and risk management improved capabilities to manage model risk during deployment.
description: 8 pages, 7 figures
Controlling the dewetting morphologies of thin liquid films by switchable substrates
Creators: name: Zitz, Stefan
name: Scagliarini, Andrea
name: Harting, Jens
Publisher: name: arXiv
Year: 2021
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Switchable and adaptive substrates emerged as valuable tools for the control of wetting and actuation of droplet motion. Here we report a computational study of the dynamics of an unstable thin liquid film deposited on a switchable substrate, modelled with a space and time varying contact angle. With a static pattern, all the fluid is drained into droplets located around contact angle minima, whereas for a sufficiently large rate of wettability variation a state consisting of metastable rivulets is observed. A criterion discriminating whether rivulets can be observed or not is identified in terms of a single dimensionless parameter. Finally, we show and explain theoretically how the film rupture times, droplet shape and rivulet life time depend on the pattern wavelength and speed.
description: 6 pages, 5 figures
A numerically stable algorithm for integrating Bayesian models using Markov melding
Creators: name: Manderson, Andrew A.
name: Goudie, Robert J. B.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Methodology (stat.ME)
subject: Applications (stat.AP)
subject: Computation (stat.CO)
subject: FOS: Computer and information sciences

description: When statistical analyses consider multiple data sources, Markov melding provides a method for combining the source-specific Bayesian models. Markov melding joins together submodels that have a common quantity. One challenge is that the prior for this quantity can be implicit, and its prior density must be estimated. We show that error in this density estimate makes the two-stage Markov chain Monte Carlo sampler employed by Markov melding unstable and unreliable. We propose a robust two-stage algorithm that estimates the required prior marginal self-density ratios using weighted samples, dramatically improving accuracy in the tails of the distribution. The stabilised version of the algorithm is pragmatic and provides reliable inference. We demonstrate our approach using an evidence synthesis for inferring HIV prevalence, and an evidence synthesis of A/H1N1 influenza.
description: 16 pages, 5 figures, 1 table. Major revisions, with substantial changes to Section 3
Rademacher expansion of a Siegel modular form for ${\cal N}= 4$ counting
Creators: name: Cardoso, Gabriel Lopes
name: Nampuri, Suresh
name: Rosselló, Martí
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Number Theory (math.NT)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The degeneracies of $1/4$ BPS states with unit torsion in heterotic string theory compactified on a six-torus are given in terms of the Fourier coefficients of the reciprocal of the Igusa cusp Siegel modular form $Φ_{10}$ of weight $10$. We use the symplectic symmetries of the latter to construct a fine-grained Rademacher type expansion which expresses these BPS degeneracies as a regularized sum over residues of the poles of $1/Φ_{10}$. The construction uses two distinct ${\rm SL}(2, \mathbb{Z})$ subgroups of ${\rm Sp}(2, \mathbb{Z})$ which encode multiplier systems, Kloosterman sums and Eichler integrals appearing therein. Additionally, it shows how the polar data are explicitly built from the Fourier coefficients of $1/η^{24}$ by means of a continued fraction structure.
description: 50 pages, 2 figures; v2: various improvements, published version
The Volterra system and topology of the isospectral variety of zero-diagonal Jacobi matrices
Creators: name: Penskoi, Alexei V.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: Algebraic Topology (math.AT)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 37K10, 57R19, 37C10

description: Topology of the isospectral variety of zero-diagonal Jacobi matrices is investigated using the Volterra system.
description: 2 pages, AMS-LaTeX, short communication; v2,v3: minor corrections; v4: shortened in order to fit "Russian Math. Surveys" requirements. See also more extended text arXiv:0705.0805
MARRYING IMMUNOTHERAPY AND CHEMOTHERAPY: A CANCER THERAPY BASED ON T LYMPHOCYTE EXPANSION AUGMENTED BY ALTERNATE GAMMA CHAIN CYTOKINES AND GEMCITABINE-MEDIATED INHIBITION OF MYELOID DERIVED SUPPRESSOR CELLS
Creators: name: Cha, Esther
Publisher: name: VCU Libraries
Year: 2009

description: VCU Theses and Dissertations
Irreducible modules over finite simple Lie pseudoalgebras III. Primitive pseudoalgebras of type H
Creators: name: Bakalov, Bojko
name: D'Andrea, Alessandro
name: Kac, Victor G.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Algebra (math.QA)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 17B35 (Primary) 16W30 (Secondary) 17B81

description: A Lie conformal algebra is an algebraic structure that encodes the singular part of the operator product expansion of chiral fields in conformal field theory. A Lie pseudoalgebra is a generalization of this structure, for which the algebra of polynomials k[\partial] in the indeterminate is replaced by the universal enveloping algebra U(d) of a finite-dimensional Lie algebra d over the base field k. The finite (i.e., finitely generated over U(d)) simple Lie pseudoalgebras were classified in our 2001 paper [BDK]. The complete list consists of primitive Lie pseudoalgebras of type W, S, H, and K, and of current Lie pseudoalgebras over them or over simple finite-dimensional Lie algebras. The present paper is the third in our series on representation theory of simple Lie pseudoalgebras. In the first paper, we showed that any finite irreducible module over a primitive Lie pseudoalgebra of type W or S is either an irreducible tensor module or the image of the differential in a member of the pseudo de Rham complex. In the second paper, we established a similar result for primitive Lie pseudoalgebras of type K, with the pseudo de Rham complex replaced by a certain reduction, called the contact pseudo de Rham complex. This reduction in the context of contact geometry was discovered by M. Rumin [Rum]. In the present paper, we show that for primitive Lie pseudoalgebras of type H, a similar to type K result holds with the contact pseudo de Rham complex replaced by a suitable complex. However, the type H case in more involved, since the annihilation algebra is not the corresponding Lie-Cartan algebra, as in other cases, but an irreducible central extension. When the action of the center of the annihilation algebra is trivial, this complex is related to work by M. Eastwood [E] on conformally symplectic geometry, and we call it conformally symplectic pseudo de Rham complex.
description: 62 pages
$\text{AdS}_2\times \text{S}^2\times \text{CY}_2$ solutions in Type IIB with 8 supersymmetries
Creators: name: Lozano, Yolanda
name: Nunez, Carlos
name: Ramirez, Anayeli
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present a new infinite family of Type IIB supergravity solutions preserving eight supercharges. The structure of the space is $\text{AdS}_2\times\text{S}^2\times \text{CY}_2\times \text{S}^1$ fibered over an interval. These solutions can be related through double analytical continuations with those recently constructed in \cite{Lozano:2020txg}. Both types of solutions are however dual to very different superconformal quantum mechanics. We show that our solutions fit locally in the class of $\text{AdS}_2\times \text{S}^2\times \text{CY}_2$ solutions fibered over a 2d Riemann surface $Σ$ constructed by Chiodaroli, Gutperle and Krym, in the absence of D3 and D7 brane sources. We compare our solutions to the global solutions constructed by Chiodaroli, D'Hoker and Gutperle for $Σ$ an annulus. We also construct a cohomogeneity-two family of solutions using non-Abelian T-duality. Finally, we relate the holographic central charge of our one dimensional system to a combination of electric and magnetic fluxes. We propose an extremisation principle for the central charge from a functional constructed out of the RR fluxes.
description: 33 pages, 4 figures
On Bibasic Humbert hypergeometric function $Φ_1$
Creators: name: Aledamat, Ayed
name: Shehata, Ayman
Publisher: name: arXiv
Year: 2022
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics

description: The main aim of this work is to derive the $q$-recurrence relations, $q$-partial derivative relations and summation formula of bibasic Humbert hypergeometric function $Φ_1$ on two independent bases $q$ and $q_{1}$ of two variables and some developments formulae, believed to be new, by using the conception of $q$-calculus.
First Stereoscopic Coronal Loop Reconstructions from Stereo Secchi Images
Creators: name: Feng, L.
name: Inhester, B.
name: Solanki, S. K.
name: Wiegelmann, T.
name: Podlipnik, B.
name: Howard, R. A.
name: Wuelser, J. -P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the first reconstruction of the three-dimensional shape of magnetic loops in an active region from two different vantage points based on simultaneously recorded images. The images were taken by the two EUVI telescopes of the SECCHI instrument onboard the recently launched STEREO spacecraft when the heliocentric separation of the two space probes was 12 degrees. We demostrate that these data allow to obtain a reliable three-dimensional reconstruction of sufficiently bright loops. The result is compared with field lines derived from a coronal magnetic field model extrapolated from a photospheric magnetogram recorded nearly simultaneously by SOHO/MDI. We attribute discrepancies between reconstructed loops and extrapolated field lines to the inadequacy of the linear force-free field model used for the extrapolation.
description: 6 pages, 5 figures
Implementation of temporal ptychography algorithm, I$^2$PIE, for improved single-beam coherent anti-Stokes Raman scattering measurements
Creators: name: Viljoen, Ruan
name: Neethling, Pieter
name: Spangenberg, Dirk
name: Heidt, Alexander
name: Frey, Hans-Martin
name: Feurer, Thomas
name: Rohwer, Erich
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We present an improvement on the signal-to-background of single-beam coherent anti-Stokes Raman scattering (SB-CARS) spectroscopy measurements for systems employing ultrafast supercontinuum sources based on all-normal dispersion photonic crystal fibers. Improvements to the signal-to-background arise in the use of a new pulse-reconstruction algorithm based on temporal ptychography, I$^2$PIE. A simple SB-CARS strategy is used to measure the spectrum of para-xylene, where the supercontinuum pulses used are compressed using multiphoton intrapulse interference phase scan (MIIPS) and, for the first time to the best of our knowledge, I$^2$PIE using the same single-beam setup. With the I$^2$PIE implementation, the signal-to-background is improved by nearly a factor of 4 in comparison with MIIPS. More notably, the integrated SB-CARS spectral intensity is increased by a factor of 6.5.
description: Copyright 2020 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited
Genetic analysis of eastern Pacific seals (Phoca vitulina richardsi) from British Columbia and parts of Alaska using mitochondrial DNA and microsatellites
Creators: name: Burg, Theresa Marie
Publisher: name: University of British Columbia
Year: 2009

description: In British Columbia the population of harbour seals, Phoca vitulina richardsi, has increased from 9,000 to 135,000 since their protection 25 years ago. Differences in pelage patterns and pupping times suggest that more than one population of harbour seals may be present in the eastern Pacific. Molecular analyses were used to investigate the genetic diversity and population structure of harbour seals along the B.C. coast and in parts of Alaska. The allele frequency at seven microsatellite loci and the haplotypic diversity–– of the mitochondrial control region (D-loop) were examined. A 475 base pair fragment containing the tRNA proline and part of the mitochondrial control region was amplified and sequenced from 128 animals. Sixty variable sites defined 72 mtDNA haplotypes with pairwise nucleotide differences as high as 5%. Only 14 haplotypes were shared between two or more seals. Some of the more frequent haplotypes were unique to specific areas, while others were distributed over a broad geographic range. Three groups representing the southern Strait of Georgia, southern B.C. and northern B.C./southeast Alaska were observed using parsimony and distance based phylogenetic reconstruction. Additional analyses using sequences from Washington and California revealed the presence of another population comprising the outer coast of Washington, Oregon and California. The order of the clades suggests that the Pacific Ocean was colonized twice. The first invasion occurred approximately 0.67 MYA and represents only a small portion of today's harbour seals in southern Vancouver Island. Seals from the second invasion, about 0.38 MYA, are distributed throughout the Pacific. Analyses of five polymorphic microsatellite loci show that the allele frequency distribution is significantly different in southern British Columbia and northern British Columbia/Alaska. Average heterozygosity was similar for northern and southern populations, however the allelic diversity was higher in the southern population. The migration rate for males based on microsatellite data (3-7 seals/ generation) was higher than that obtained for females from the mtDNA (0.3 females/ generation). This suggests that although migration rates are low they are sufficient to allow gene flow between the two populations.
Students Readiness for E-learning in the Universities in Yemen
Creators: name: Al-Absi, Adnan Sharaf Ali Yousef
name: Peneva, Ivelina
name: Yordzhev, Krasimir
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: The e-learning is an advanced version of traditional education. It is defined as a way of learning by using the communication mechanisms of modern computer networks and multimedia, including voice, image, and graphics and mechanisms to search electronic libraries, as well as web portals, whether in the context of distance learning or in the classroom. The people who engage in the transition to web-supported education are the administrative staff, the faculty, and the students. They all have their needs and they all should meet specific requirements in order to facilitate the transition. The article presents the results of questionnaire research of the students readiness for e-learning in Yemeni universities.
Recovering 3D Human Mesh from Monocular Images: A Survey
Creators: name: Tian, Yating
name: Zhang, Hongwen
name: Liu, Yebin
name: Wang, Limin
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Graphics (cs.GR)
subject: FOS: Computer and information sciences

description: Estimating human pose and shape from monocular images is a long-standing problem in computer vision. Since the release of statistical body models, 3D human mesh recovery has been drawing broader attention. With the same goal of obtaining well-aligned and physically plausible mesh results, two paradigms have been developed to overcome challenges in the 2D-to-3D lifting process: i) an optimization-based paradigm, where different data terms and regularization terms are exploited as optimization objectives; and ii) a regression-based paradigm, where deep learning techniques are embraced to solve the problem in an end-to-end fashion. Meanwhile, continuous efforts are devoted to improving the quality of 3D mesh labels for a wide range of datasets. Though remarkable progress has been achieved in the past decade, the task is still challenging due to flexible body motions, diverse appearances, complex environments, and insufficient in-the-wild annotations. To the best of our knowledge, this is the first survey that focuses on the task of monocular 3D human mesh recovery. We start with the introduction of body models and then elaborate recovery frameworks and training objectives by providing in-depth analyses of their strengths and weaknesses. We also summarize datasets, evaluation metrics, and benchmark results. Open issues and future directions are discussed in the end, hoping to motivate researchers and facilitate their research in this area. A regularly updated project page can be found at https://github.com/tinatiansjz/hmr-survey.
description: Published in IEEE TPAMI, Survey on monocular 3D human mesh recovery, Project page: https://github.com/tinatiansjz/hmr-survey
Numerical Renormalization Group Approach to a Quantum Dot Coupled to Normal and Superconducting Leads
Creators: name: Tanaka, Yoichi
name: Kawakami, Norio
name: Oguri, Akira
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study transport through a quantum dot coupled to normal and superconducting leads using the numerical renormalization group method. We show that the low-energy properties of the system are described by the local Fermi liquid theory despite of the superconducting correlations penetrated into the dot due to a proximity effect. We calculate the linear conductance due to the Andreev reflection in the presence of the Coulomb interaction. It is demonstrated that the maximum structure appearing in the conductance clearly characterizes a crossover between two distinct spin-singlet ground states, i.e. the superconducting singlet state and the Kondo singlet state. It is further elucidated that the gate-voltage dependence of the conductance shows different behavior in the superconducting singlet region from that in the Kondo singlet region.
description: 10 pages, 6 figures; a typo in eq. (B.5) corrected, which does not affect any other results of the paper
Stability analysis and optimal control of a fractional HIV-AIDS epidemic model with memory and general incidence rate
Creators: name: Boukhouima, Adnane
name: Lotfi, El Mehdi
name: Mahrouf, Marouane
name: Rosa, Silverio
name: Torres, Delfim F. M.
name: Yousfi, Noura
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optimization and Control (math.OC)
subject: Populations and Evolution (q-bio.PE)
subject: FOS: Mathematics
subject: FOS: Biological sciences

description: We investigate the celebrated mathematical SICA model but using fractional differential equations in order to better describe the dynamics of HIV-AIDS infection. The infection process is modelled by a general functional response and the memory effect is described by the Caputo fractional derivative. Stability and instability of equilibrium points are determined in terms of the basic reproduction number. Furthermore, a fractional optimal control system is formulated and the best strategy for minimizing the spread of the disease into the population is determined through numerical simulations based on the derived necessary optimality conditions.
description: This is a preprint of a paper whose final and definite form is with 'The European Physical Journal Plus', E-ISSN 2190-5444. Submitted: 02-Feb-2020 / Revised: 20-Oct-2020 and 24-Nov-2020 / Accepted: 08-Dec-2020
Estimating and Mitigating the Congestion Effect of Curbside Pick-ups and Drop-offs: A Causal Inference Approach
Creators: name: Liu, Xiaohui
name: Qian, Sean
name: Teo, Hock-Hai
name: Ma, Wei
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Curb space is one of the busiest areas in urban road networks. Especially in recent years, the rapid increase of ride-hailing trips and commercial deliveries has induced massive pick-ups/drop-offs (PUDOs), which occupy the limited curb space that was designed and built decades ago. These PUDOs could jam curbside utilization and disturb the mainline traffic flow, evidently leading to significant negative societal externalities. However, there is a lack of an analytical framework that rigorously quantifies and mitigates the congestion effect of PUDOs in the system view, particularly with little data support and involvement of confounding effects. To bridge this research gap, this paper develops a rigorous causal inference approach to estimate the congestion effect of PUDOs on general regional networks. A causal graph is set to represent the spatio-temporal relationship between PUDOs and traffic speed, and a double and separated machine learning (DSML) method is proposed to quantify how PUDOs affect traffic congestion. Additionally, a re-routing formulation is developed and solved to encourage passenger walking and traffic flow re-routing to achieve system optimization. Numerical experiments are conducted using real-world data in the Manhattan area. On average, 100 additional units of PUDOs in a region could reduce the traffic speed by 3.70 and 4.54 mph on weekdays and weekends, respectively. Re-routing trips with PUDOs on curb space could respectively reduce the system-wide total travel time by 2.44% and 2.12% in Midtown and Central Park on weekdays. Sensitivity analysis is also conducted to demonstrate the effectiveness and robustness of the proposed framework.
description: Accepted at Transportation Science
Traveling wave solutions for a class of discrete diffusive SIR epidemic model
Creators: name: Zhang, Ran
name: Wang, Jinliang
name: Liu, Shengqiang
Publisher: name: arXiv
Year: 2020
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 35C07, 35K57, 92D30

description: This paper is concerned with the conditions of existence and nonexistence of traveling wave solutions (TWS) for a class of discrete diffusive epidemic models. We find that the existence of TWS is determined by the so-called basic reproduction number and the critical wave speed: When the basic reproduction number R0 greater than 1, there exists a critical wave speed c* > 0, such that for each c >= c * the system admits a nontrivial TWS and for c < c* there exists no nontrivial TWS for the system. In addition, the boundary asymptotic behaviour of TWS is obtained by constructing a suitable Lyapunov functional and employing Lebesgue dominated convergence theorem. Finally, we apply our results to two discrete diffusive epidemic models to verify the existence and nonexistence of TWS.
Bragg spectroscopy of trapped one dimensional strongly interacting bosons in optical lattices: Probing the cake-structure
Creators: name: Pupillo, Guido
name: Rey, Ana Maria
name: Batrouni, G. George
Publisher: name: arXiv
Year: 2006
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We study Bragg spectroscopy of strongly interacting one dimensional bosons loaded in an optical lattice plus an additional parabolic potential. We calculate the dynamic structure factor by using Monte Carlo simulations for the Bose-Hubbard Hamiltonian, exact diagonalizations and the results of a recently introduced effective fermionization (EF) model. We find that, due to the system's inhomogeneity, the excitation spectrum exhibits a multi-branched structure, whose origin is related to the presence of superfluid regions with different densities in the atomic distribution. We thus suggest that Bragg spectroscopy in the linear regime can be used as an experimental tool to unveil the shell structure of alternating Mott insulator and superfluid phases characteristic of trapped bosons.
description: 7 pages, 4 figures
EDGE-CALIFA survey: Self-regulation of Star formation at kpc scales
Creators: name: Barrera-Ballesteros, J. K.
name: Sánchez, S. F.
name: Heckman, T.
name: Wong, T.
name: Bolatto, A.
name: Ostriker, E.
name: Rosolowsky, E.
name: Carigi, L.
name: Vogel, S.
name: Levy, R. C.
name: Colombo, D.
name: Luo, Yufeng
name: Cao, Yixian
name: team, the EDGE-CALIFA
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the relation between the star formation rate surface density, $Σ_{\rm SFR}$, and the hydrostatic mid-plane pressure, P$_{\rm h}$, for 4260 star-forming regions of kpc size located in 96 galaxies included in the EDGE-CALIFA survey covering a wide range of stellar masses and morphologies. We find that these two parameters are tightly correlated, exhibiting smaller scatter and strong correlation in comparison to other star-forming scaling relations. A power-law, with a slightly sub-linear index, is a good representation of this relation. Locally, the residuals of this correlation show a significant anti-correlation with both the stellar age and metallicity whereas the total stellar mass may also play a secondary role in shaping the $Σ_{\rm SFR}$ - P$_{\rm h}$ relation. For our sample of active star-forming regions (i.e., regions with large values of H$α$ equivalent width), we find that the effective feedback momentum per unit stellar mass ($p_\ast/m_\ast$),measured from the P$_{\rm h}$ / $Σ_{\rm SFR}$ ratio increases with P$_{\rm h}$. The median value of this ratio for all the sampled regions is larger than the expected momentum just from supernovae explosions. Morphology of the galaxies, including bars, does not seem to have a significant impact in the $Σ_{\rm SFR}$ - P$_{\rm h}$ relation. Our analysis suggests that self regulation of the $Σ_{\rm SFR}$ at kpc scales comes mainly from momentum injection to the interstellar medium from supernovae explosions. However, other mechanism in disk galaxies may also play a significant role in shaping the $Σ_{\rm SFR}$ at local scales. Our results also suggest that P$_{\rm h}$ can be considered as the main parameter that modulates star formation at kpc scales, rather than individual components of the baryonic mass.
description: 19 pages, 12 figures, submitted to MNRAS November 16 2020
Ranking In Generalized Linear Bandits
Creators: name: Shidani, Amitis
name: Deligiannidis, George
name: Doucet, Arnaud
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (stat.ML)
subject: Information Retrieval (cs.IR)
subject: Machine Learning (cs.LG)
subject: Optimization and Control (math.OC)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: We study the ranking problem in generalized linear bandits. At each time, the learning agent selects an ordered list of items and observes stochastic outcomes. In recommendation systems, displaying an ordered list of the most attractive items is not always optimal as both position and item dependencies result in a complex reward function. A very naive example is the lack of diversity when all the most attractive items are from the same category. We model the position and item dependencies in the ordered list and design UCB and Thompson Sampling type algorithms for this problem. Our work generalizes existing studies in several directions, including position dependencies where position discount is a particular case, and connecting the ranking problem to graph theory.
Constraining the Jet Launching Time of GRB 170817A by Utilizing the Baryon Loading
Creators: name: Ren, Jia
name: Lin, Da-Bin
name: Zhang, Lu-lu
name: Wang, Kai
name: Li, Xiao-yan
name: Wang, Xiang-Gao
name: Liang, En-Wei
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The observed delay of GRB 170817A relative to GW170817 carries significant information about gamma-ray burst (GRB) physics and is subject to intense debate. In this letter, we put forward an approach to discuss the major source of this time delay. First of all, we use the structured jet model to fit the X-ray/optical/radio afterglows of GRB 170817A together with superluminal motion measured by the Very Long Baseline Interferometry. Our structured jet is modelled with angle-dependent energy and baryon loading. It is found that our model can well fit the afterglows of GRB 170817A. After that, the baryon loading in the jet is inferred based on our fitting results. By comparing the baryon loading to the mass outflow in different stages, we infer that the time lag of the jet launch relative to the merger is less than hundreds or tens of milliseconds. It suggests that the time delay of GRB 170817A relative to GW170817 is defined mostly by the spreading time of the jet propagating to its dissipation radius.
description: 13 pages, 4 figures, ApJL accepted
Representations of molecules and materials for interpolation of quantum-mechanical simulations via machine learning
Creators: name: Langer, Marcel F.
name: Goeßmann, Alex
name: Rupp, Matthias
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Machine Learning (cs.LG)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Computational study of molecules and materials from first principles is a cornerstone of physics, chemistry, and materials science, but limited by the cost of accurate and precise simulations. In settings involving many simulations, machine learning can reduce these costs, often by orders of magnitude, by interpolating between reference simulations. This requires representations that describe any molecule or material and support interpolation. We comprehensively review and discuss current representations and relations between them, using a unified mathematical framework based on many-body functions, group averaging, and tensor products. For selected state-of-the-art representations, we compare energy predictions for organic molecules, binary alloys, and Al-Ga-In sesquioxides in numerical experiments controlled for data distribution, regression method, and hyper-parameter optimization.
description: 20 pages, 6 figures, excluding supplement (19 pages, 5 figures); v2: extended review and discussion, more representations covered, edited for clarity. For additional information, including datasets, results, and software see https://marcel.science/repbench
(Quasi)-exactly solvable quasinormal modes
Creators: name: Cho, Hing-Tong
name: Ho, Choon-Lin
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider quasinormal modes with complex energies from the point of view of the theory of quasi-exactly solvable (QES) models. We demonstrate that it is possible to find new potentials which admit exactly solvable or QES quasinormal modes by suitable complexification of parameters defining the QES potentials. Particularly, we obtain one QES and four exactly solvable potentials out of the five one-dimensional QES systems based on the $sl(2)$ algebra.
description: 5 pages, 1 figure. Replaced with version to appear in J. Phys. A
Geodesics on an arbitrary ellipsoid of revolution
Creators: name: Karney, Charles F. F.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Geophysics (physics.geo-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The algorithms given in Karney, J. Geodesy 87, 43-55 (2013), to compute geodesics on terrestrial ellipsoids are extended to apply to ellipsoids of revolution with arbitrary eccentricity. For the direct and inverse geodesic problems, this entails implementing the formulation in terms of elliptic integrals given by Legendre and Cayley. The integral for the area of geodesic polygons is computed in terms of the discrete sine transform of the integrand. In all cases, accuracy close to full machine precision is achieved. An open-source implementation of these algorithms is available.
description: ReVTeX, 12 pages, 6 figures. In this version: specify pdflatex to fix problems with the figures + other minor revisions
The environmental dependence of X-ray AGN activity at $z\sim0.4$
Creators: name: Noordeh, E.
name: Canning, R. E. A.
name: King, A.
name: Allen, S. W.
name: Mantz, A.
name: Morris, R. G.
name: Ehlert, S.
name: von der Linden, A.
name: Brandt, W. N.
name: Luo, B.
name: Xue, Y. Q.
name: Kelly, P.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present an analysis of the X-ray Active Galactic Nucleus (AGN) population in a sample of seven massive galaxy clusters in the redshift range $0.356.8\times10^{42}~\mathrm{erg~s^{-1}}$, within $r\leq2r_{500}$ (approximately the virial radius), we find that the cluster AGN space density scales with cluster mass as $\sim M^{-2.0^{+0.8}_{-0.9}}$. This result rules out zero mass dependence of the cluster X-ray AGN space density at the 2.5$σ$ level. We compare our cluster X-ray AGN sample to a control field with identical selection and find that the cluster AGN fraction is significantly suppressed relative to the field when considering the brightest galaxies with $V<21.5$. For fainter galaxies, this difference is not present. Comparing the X-ray hardness ratios of cluster member AGN to those in the control field, we find no evidence for enhanced X-ray obscuration of cluster member AGN. Lastly, we see tentative evidence that disturbed cluster environments may contribute to enhanced AGN activity.
description: 13 pages, 11 figures, accepted for publication in MNRAS
Rapidity Dependence of HBT radii based on a hydrodynamical model
Creators: name: Morita, Kenji
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We calculate two-pion correlation functions at finite rapidities based on a hydrodynamical model which does not assume explicit boost invariance along the collision axis. Extracting the HBT radii through $χ^2$ fits in both Cartesian and Yano-Koonin-Podgoretski\uı parametrizations, we compare them with the experimental results obtained by the PHOBOS. Based on the results, we discuss longitudinal expansion dynamics.
description: 8 pages, 10 figures, talk given at II Workshop on Particle Correlation and Femtoscopy (WPCF 2006), Sep 9-11, Sao Paulo, Brazil. Revised version to be published in Braz.J.Phys
Global room-temperature superconductivity in graphite
Creators: name: Kopelevich, Y. V.
name: Torres, J. H. S.
name: da Silva, R. Ricardo
name: Diamantini, M. C.
name: Trugenbergerand, C. A.
name: Vinokur, V. M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Room temperature superconductivity under normal conditions has been a major challenge of physics and material science since its very discovery. Here we report the global room-temperature superconductivity observed in cleaved highly oriented pyrolytic graphite carrying dense arrays of nearly parallel surface line defects. The multiterminal measurements performed at the ambient pressure in the temperature interval 4.5 K < T < 300 K and at magnetic fields 0 < B < 9 T applied perpendicular to the basal graphitic planes reveal that the superconducting critical current I_c(T,B) is governed by the normal state resistance RN(T, B) so that I_c(T,B) is proportional to 1/R_N(T, B). Magnetization M(T, B) measurements of superconducting screening and hysteresis loops together with the critical current oscillations with temperature that are characteristic for superconductor-ferromagnet-superconductor Josephson chains, provide strong support for occurrence of superconductivity at T > 300 K. We develop a theory of global superconductivity emerging in the array of linear structural defects which well describes the experimental findings and demonstrate that global superconductivity arises as a global phase coherence of superconducting granules in linear defects promoted by the stabilizing effect of underlying Bernal graphite via tunneling coupling to the three dimensional (3D) material.
description: Published version
{\sc mirkwood:} Fast and Accurate SED Modeling Using Machine Learning
Creators: name: Gilda, Sankalp
name: Lower, Sidney
name: Narayanan, Desika
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Traditional spectral energy distribution (SED) fitting codes used to derive galaxy physical properties are often uncertain at the factor of a few level owing to uncertainties in galaxy star formation histories and dust attenuation curves. Beyond this, Bayesian fitting (which is typically used in SED fitting software) is an intrinsically compute-intensive task, often requiring access to expensive hardware for long periods of time. To overcome these shortcomings, we have developed {\sc mirkwood}: a user-friendly tool comprising of an ensemble of supervised machine learning-based models capable of non-linearly mapping galaxy fluxes to their properties. By stacking multiple models, we marginalize against any individual model's poor performance in a given region of the parameter space. We demonstrate \textsc{mirkwood}'s significantly improved performance over traditional techniques by training it on a combined data set of mock photometry of z=0 galaxies from the \textsc{Simba}, \textsc{EAGLE} and \textsc{IllustrisTNG} cosmological simulations, and comparing the derived results with those obtained from traditional SED fitting techniques. \textsc{mirkwood} is also able to account for uncertainties arising both from intrinsic noise in observations, and from finite training data and incorrect modeling assumptions. To increase the added value to the observational community, we use Shapley value explanations (SHAP) to fairly evaluate the relative importance of different bands to understand why particular predictions were reached. We envisage \textsc{mirkwood} to be an evolving, open-source framework that will provide highly accurate physical properties from observations of galaxies as compared to traditional SED fitting.
description: 26 pages + 4 pages for appendix. Submitted to ApJ. Comments welcome
Learning Multi-Object Symbols for Manipulation with Attentive Deep Effect Predictors
Creators: name: Ahmetoglu, Alper
name: Oztop, Erhan
name: Ugur, Emre
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: In this paper, we propose a concept learning architecture that enables a robot to build symbols through self-exploration by interacting with a varying number of objects. Our aim is to allow a robot to learn concepts without constraints, such as a fixed number of interacted objects or pre-defined symbolic structures. As such, the sought architecture should be able to build symbols for objects such as single objects that can be grasped, object stacks that cannot be grasped together, or other composite dynamic structures. Towards this end, we propose a novel architecture, a self-attentive predictive encoder-decoder network with binary activation layers. We show the validity of the proposed network through a robotic manipulation setup involving a varying number of rigid objects. The continuous sensorimotor experience of the robot is used by the proposed network to form effect predictors and symbolic structures that describe the interaction of the robot in a discrete way. We showed that the robot acquired reasoning capabilities to encode interaction dynamics of a varying number of objects in different configurations using the discovered symbols. For example, the robot could reason that (possible multiple numbers of) objects on top of another object would move together if the object below is moved by the robot. We also showed that the discovered symbols can be used for planning to reach goals by training a higher-level neural network that makes pure symbolic reasoning.
description: 7 pages, 7 figures