检索结果-内蒙古大学图书馆

Synchronization of coupled second-order kuramoto-sakaguchi oscillators

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Gao, Jian Efstathiou, Konstantinos Bernoulli Institute for Mathematics Computer Science and Artificial Intelligence University of Groningen P.O. Box 407 GroningenAK9700 Netherlands Division of Natural and Applied Sciences Zu Chongzhi Center for Mathematics and Computational Science Duke Kunshan University No. 8 Duke Avenue Kunshan215316 China

We study the synchronization of oscillators with inertias and phase shifts, namely the second-order Kuramoto-Sakaguchi model. Using the self-consistent method, we find that the effect of inertia is the introduction of effective phase shifts. The discontinuous synchronization transition of the Kuramoto-Sakaguchi model changes to a continuous one when the value of inertia is small. In addition, we find a new synchronization process, in which with increasing coupling strength the system reaches an oscillating state instead of complete synchronization due to the cross-effect of phase shifts and inertias. Through numerical simulations, the same type of synchronization process is also found for oscillators in complex networks, including scale-free, small-world and random networks. Copyright © 2020, The Authors. All rights reserved.

关键词： Synchronization

Crouzeix’s Conjecture and Related Problems

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Bickel, Kelly Gorkin, Pamela Greenbaum, Anne Ransford, Thomas Schwenninger, Felix Wegert, Elias Department of Mathematics Bucknell University LewisburgPA17837 United States Department of Mathematics Bucknell University LewisburgPA17837 United States Department of Applied Mathematics University of Washington Département de mathématiques et de statistique Université Laval QuébecQCG1V 0A6 Canada Department of Mathematics Universität Hamburg Department of Applied Mathematics University of Twente Netherlands Department of Mathematics and Computer Science Technische Universität Bergakademie Freiberg Division of Mathematical Sciences National Science Foundation United States NSERC and the Canada Research Chairs program

In this paper, we establish several results related to Crouzeixs conjecture. We show that the conjecture holds for contractions with eigenvalues that are sufficiently well-separated. This separation is measured by the so-called separation constant, which is defined in terms of the pseudohyperbolic metric. Moreover, we study general properties of related extremal functions and associated vectors. Throughout, compressions of the shift serve as illustrating examples which also allow for refined *** Codes 47A25, 47A12, 15A60, 47A20, 30J10 Copyright © 2020, The Authors. All rights reserved.

关键词： Eigenvalues and eigenfunctions

OBTAINING HIGHER-ORDER GALERKIN ACCURACY WHEN THE BOUNDARY IS POLYGONALLY APPROXIMATED

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Dupont, Todd Guzmán, Johnny Scott, L. Ridgway University of Chicago Departments of Computer Science and of Mathematics ChicagoIL60637 United States Division of Applied Mathematics Brown University Box F 182 George Street ProvidenceRI02912 United States University of Chicago Emeritus ChicagoIL60637 United States

We study two techniques for correcting the geometrical error associated with domain approximation by a polygon. The first was introduced some time ago [2] and leads to a nonsymmetric formulation for Poisson’s equation. We introduce a new technique that yields a symmetric formulation and has similar performance. We compare both methods on a simple test *** Codes 65N30 Copyright © 2020, The Authors. All rights reserved.

关键词： Poisson equation

Galaxy clusters at z ∼ 1 imaged by ALMA with the Sunyaev–Zel’dovich effect

学校读者我要写书评

暂无评论

Publications of the Astronomical Society of Japan 2023年第2期75卷 311-337页

作者： Kitayama, Tetsu Ueda, Shutaro Okabe, Nobuhiro Akahori, Takuya Hilton, Matt Hughes, John P. Ichinohe, Yuto Kohno, Kotaro Komatsu, Eiichiro Lin, Yen-Ting Miyatake, Hironao Oguri, Masamune Sifón, Cristóbal Takakuwa, Shigehisa Takizawa, Motokazu Tsutsumi, Takahiro van Marrewijk, Joshiwa Wollack, Edward J. Department of Physics Toho University 2-2-1 Miyama Chiba Funabashi274-8510 Japan No. 1 Section 4 Roosevelt Road Taipei10617 Taiwan Institute of Astronomy National Tsing Hua University Hsinchu30013 Taiwan Department of Physics Hiroshima University 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima739-8526 Japan Astrophysical Science Center Hiroshima University 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima739-8526 Japan Core Research for Energetic Universe Department of Physics Hiroshima University 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima739-8526 Japan Physics Program Graduate School of Advanced Science and Engineering Hiroshima University 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima739-8526 Japan Mizusawa VLBI observatory National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Operation Division SKA Observatory Jodrell Bank Lower Withington MacclesfieldSK11 9DL United Kingdom Astrophysics Research Centre University of KwaZulu-Natal Westville Campus Durban4041 South Africa School of Mathematics Statistics & Computer Science University of KwaZulu-Natal Westville Campus Durban4041 South Africa Wits Centre for Astrophysics School of Physics University of the Witwatersrand Private Bag 3 Johannesburg2050 South Africa Department of Physics and Astronomy Rutgers The State University of New Jersey PiscatawayNJ08854-8019 United States Department of Physics Rikkyo University 3-34-1 Nishi-Ikebukuro Toshima-ku Tokyo171-8501 Japan Institute of Astronomy School of Science The University of Tokyo 2-21-1 Osawa Mitaka Tokyo181-0015 Japan Research Center for the Early Universe School of Science The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan Max-Planck-Institut für Astrophysik Karl-Schwarzschild Str. 1 GarchingD-85741 Germany The University of Tokyo Institutes for Advanced Study The University of Tokyo 5-1-5 Kashiwanoha Chiba Kashiwa277-8583 Japan Nagoya University Furo-cho Chikusa-

We present high angular resolution measurements of the thermal Sunyaev–Zel’dovich effect (SZE) toward two galaxy clusters, RCS J2319+0038 at z = 0.9 and HSC J0947−0119 at z = 1.1, by the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 3. They are supplemented with available Chandra X-ray data, optical data taken by Hyper Suprime-Cam on Subaru, and millimeter-wave SZE data from the Atacama Cosmology Telescope. Taking into account departures from spherical symmetry, we have reconstructed non-parametrically the inner pressure profile of two clusters as well as electron temperature and density profiles for RCS J2319+0038. This is one of the first such measurements for an individual cluster at z 0.9. We find that the inner pressure profile of both clusters is much shallower than that of local cool-core clusters. Our results consistently suggest that RCS J2319+0038 hosts a weak cool core, where radiative cooling is less significant than in local cool cores. On the other hand, HSC J0947−0119 exhibits an even shallower pressure profile than RCS J2319+0038 and is more likely to be a non-cool-core cluster. The SZE centroid position is offset by more than 140 h−170 kpc from the peaks of galaxy distribution in HSC J0947−0119, suggesting a stronger influence of mergers in this cluster. We conclude that these distant clusters are at a very early stage of developing the cool cores typically found in clusters at lower redshifts. © The Author(s) 2023. Published by Oxford University Press on behalf of the Astronomical Society of Japan.

关键词： Millimeter waves

Topological data analysis of black hole images

学校读者我要写书评

暂无评论

Physical Review D 2022年第2期106卷 023017-023017页

作者： Pierre Christian Chi-kwan Chan Anthony Hsu Feryal Özel Dimitrios Psaltis Iniyan Natarajan Physics Department Fairfield University 1073 N Benson Road Fairfield Connecticut 06824 USA Department of Astronomy University of Arizona 933 North Cherry Avenue Tucson Arizona 85721 USA Data Science Institute University of Arizona 1230 N. Cherry Avenue Tucson Arizona 85721 USA Program in Applied Mathematics University of Arizona 617 N. Santa Rita Tucson Arizona 85721 USA Department of Computer Science University of Arizona 1040 4th Street Tucson Arizona 85721 USA Wits Centre for Astrophysics University of the Witwatersrand 1 Jan Smuts Avenue Braamfontein Johannesburg 2050 South Africa South African Radio Astronomy Observatory Observatory 7925 Cape Town South Africa

Features such as photon rings, jets, or hot spots can leave particular topological signatures in a black hole image. As such, topological data analysis can be used to characterize images resulting from high-resolution observations (synthetic or real) of black holes in the electromagnetic sector. We demonstrate that persistent homology allows for this characterization to be made automatically by counting the number of connected components and one-dimensional holes. Further, persistent homology also allows for the distance between connected components or the diameter of holes to be extracted from the image. In order to apply persistent homology on synthetic black hole images, we also introduce metronization, a new algorithm to prepare black hole images in a form that is suitable for topological analysis.

关键词： Astronomical black holes

Antenna characterization for the HIRAX experiment

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Kuhn, Emily R. Saliwanchik, Benjamin R.B. Bandura, Kevin Bianco, Michele Chiang, H. Cynthia Crichton, Devin Deng, Meiling Gaddam, Sindhu Gerodias, Kit Gumba, Austin Harris, Maile Moodley, Kavilan Mugundhan, V. Newburgh, Laura Peterson, Jeffrey Pieters, Elizabeth Polish, Anna R. Refregier, Alexandre Sampath, Ajith Santos, Mario G. Sengate, Onkabetse Sievers, Jonathan Smith, Ema Tyndall, Will Walters, Anthony Weltman, Amanda Wulf, Dallas Department of Physics Yale University New HavenCT United States Instrumentation Division Brookhaven National Laboratory UptonNY United States Department of Computer Science and Electrical Engineering Center for GravitationalWaves and Cosmology West Virginia University MorgantownWV United States Laboratoire d'Astrophysique Ecole Polytechnique Federale de Lausanne EPFL Observatoire de Sauverny Versoix Switzerland Department of Physics McGill University MontrealQC Canada Institute for Particle Physics and Astrophysics ETH Zurich Zurich Switzerland Perimeter Institute for Theoretical Physics WaterlooON Canada Dominion Radio Astrophysical Observatory KaledenBC Canada School of Mathematics Statistics and Computer Science UKZN Saudi Arabia Astrophysics Research Centre UKZN Saudi Arabia Dept of Physics Carnegie Mellon University PittsburghPA United States Department of Physics and Astronomy University of Western Cape Cape Town7535 South Africa School of Chemistry and Physics UKZN Saudi Arabia Department of Mathematics and Applied Mathematics University of Cape Town Saudi Arabia

The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) aims to improve constraints on the dark energy equation of state through measurements of large-scale structure at high redshift (0.8 700MHz. Noise temperature measurements of the HIRAX feeds were performed in a custom apparatus built at Yale. In this system, identical loads, one cryogenic and the other at room temperature, are used to take a differential (Y-factor) measurement from which the noise of the system is inferred. Several measurement sets have been conducted using the system, involving CHIME feeds as well as four of the HIRAX active feeds. These measurements give the first noise temperature measurements of the HIRAX feed, revealing a ∼60K noise temperature (relative to 30K target) with 40K peak- to-peak frequency-dependent features, and provide the first demonstration of feed repeatability. Both findings inform current and future feed designs. © 2022, CC BY.

关键词： Equations of state

Association Between Long‑Term Exposure to Air Pollution and the Rate of Mortality After Hip Fracture Surgery in Patients Older Than 60 Years: Nationwide Cohort Study in Taiwan

学校读者我要写书评

暂无评论

JMIR Public Health and Surveillance 2024年 10卷 e46591页

作者： Chuang, Shu-Han Kuo, Yi-Jie Huang, Shu-Wei Zhang, Han-Wei Peng, Hsiao-Ching Chen, Yu-Pin Division of General Practice Department of Medical Education Changhua Christian Hospital Changhua Taiwan Department of Orthopedics Wan Fang Hospital Taipei Medical University Taipei City Taiwan Department of Orthopedics School of Medicine College of Medicine Taipei Medical University Taipei Taiwan Department of Applied Science National Taitung University Taitung County Taitung City Taiwan MetaTrial Research Center Biomedica Corporation New Taipei Taiwan Program for Aging China Medical University Taichung Taiwan Institute of Population Health Sciences National Health Research Institutes Miaoli Taiwan Department of Electrical and Computer Engineering Institute of Electrical Control Engineering National Yang Ming Chiao Tung University Hsinchu Taiwan

BACKGROUND: To enhance postoperative patient survival, particularly in older adults, understanding the predictors of mortality following hip fracture becomes paramount. Air pollution, a prominent global environmental issue, has been linked to heightened morbidity and mortality across a spectrum of diseases. Nevertheless, the precise impact of air pollution on hip fracture outcomes remains elusive. OBJECTIVE: This retrospective study aims to comprehensively investigate the profound influence of a decade-long exposure to 12 diverse air pollutants on the risk of post-hip fracture mortality among older Taiwanese patients (older than 60 years). We hypothesized that enduring long-term exposure to air pollution would significantly elevate the 1-year mortality rate following hip fracture surgery. METHODS: From Taiwan's National Health Insurance Research Database, we obtained the data of patients who underwent hip fracture surgery between July 1, 2003, and December 31, 2013. Using patients' insurance registration data, we estimated their cumulative exposure levels to sulfur dioxide (SO2), carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), particulate matter having a size of <10 μm (PM10), particulate matter having a size of <2.5 μm (PM2.5), nitrogen oxides (NOX), nitrogen monoxide (NO), nitrogen dioxide (NO2), total hydrocarbons (THC), nonmethane hydrocarbons (NMHC), and methane (CH4). We quantified the dose-response relationship between these air pollutants and the risk of mortality by calculating hazard ratios associated with a 1 SD increase in exposure levels over a decade. RESULTS: Long-term exposure to SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 demonstrated significant associations with heightened all-cause mortality risk within 1 year post hip fracture surgery among older adults. For older adults, each 1 SD increment in the average exposure levels of SO2, CO, PM10, PM2.5, NOX, NO, NO2, THC, NMHC, and CH4 corresponded to a substantial escalation in mort

关键词： air pollution environmental hazard exposure hazard hip fracture morbidity mortality older adult

Recent advances and applications of deep learning methods in materials science

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Choudhary, Kamal DeCost, Brian Chen, Chi Jain, Anubhav Tavazza, Francesca Cohn, Ryan WooPark, Cheol Choudhary, Alok Agrawal, Ankit Billinge, Simon J.L. Holm, Elizabeth Ong, Shyue Ping Wolverton, Chris Materials Science and Engineering Division National Institute of Standards and Technology GaithersburgMD20899 United States Theiss Research San diegoCA92037 United States Material Measurement Science Division National Institute of Standards and Technology GaithersburgMD20899 United States Department of NanoEngineering University of California San Diego CA92093 United States Energy Technologies Area Lawrence Berkeley National Laboratory BerkeleyCA United States Department of Materials Science and Engineering Carnegie Mellon University PittsburghPA15213 United States Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Electrical and Computer Engineering Northwestern University EvanstonIL60208 United States Department of Applied Physics and Applied Mathematics and the Data Science Institute Fu Foundation School of Engineering and Applied Sciences Columbia University New YorkNY10027 United States

Deep learning (DL) is one of the fastest growing topics in materials data science, with rapidly emerging applications spanning atomistic, image-based, spectral, and textual data modalities. DL allows analysis of unstructured data and automated identification of features. Recent development of large materials databases has fueled the application of DL methods in atomistic prediction in particular. In contrast, advances in image and spectral data have largely leveraged synthetic data enabled by high quality forward models as well as by generative unsupervised DL methods. In this article, we present a high-level overview of deep-learning methods followed by a detailed discussion of recent developments of deep learning in atomistic simulation, materials imaging, spectral analysis, and natural language processing. For each modality we discuss applications involving both theoretical and experimental data, typical modeling approaches with their strengths and limitations, and relevant publicly available software and datasets. We conclude the review with a discussion of recent cross-cutting work related to uncertainty quantification in this field and a brief perspective on limitations, challenges, and potential growth areas for DL methods in materials science. The application of DL methods in materials science presents an exciting avenue for future materials discovery and design. © 2021, CC BY.

关键词： Application programs

Correction: Extremely boosted neural network for more accurate multi-stage Cyber attack prediction in cloud computing environment

学校读者我要写书评

暂无评论

Journal of Cloud Computing 2023年第1期12卷 1-1页

作者： Dalal, Surjeet Manoharan, Poongodi Kumar, Lilhore Umesh Seth, Bijeta alsekait, Deema Mohammed Simaiya, Sarita Hamdi, Mounir Raahemifar, Kaamran Department of Computer Science and Engineering Amity University Haryana Gurugram India Division of Information and Computing Technology College of Science and Engineering Hamad Bin Khalifa University Qatar Foundation Doha Qatar School of Computing University of Louisiana Lafayette USA Department of Computer Science and Engineering Chandigarh University Mohali India Department of Computer Science and Engineering B. M. Institute of Engineering & Technology Sonipat India Department of Computer Science and Information Technology Applied College Princess Nourah Bint Abdulrahman University Riyadh Saudi Arabia College of Information Sciences and Technology Data Science and Artificial Intelligence Program State College USA School of Optometry and Vision Science Faculty of Science University of Waterloo Waterloo Canada Faculty of Engineering University of Waterloo Waterloo Canada