检索结果-内蒙古大学图书馆

Contrasting 2008-2019 Trends in Tropospheric Ozone Hotspots in Spain

学校读者我要写书评

暂无评论

SSRN

SSRN 2022年

作者： Massagué, Jordi Escudero, Miguel Alastuey, Andrés Mantilla, Enrique Monfort, Eliseo Gangoiti, Gotzon García-Pando, Carlos Pérez Querol, Xavier Barcelona08034 Spain Department of Mining Industrial and ICT Engineering Universitat Politècnica de Catalunya - BarcelonaTech UPC Manresa08242 Spain Department of Applied Physics School of Engineering and Architecture Universidad de Zaragoza Zaragoza50018 Spain Mediterranean Center for Environmental Studies CEAM Valencia46980 Spain Universitat Jaume I Castellón12006 Spain Faculty of Engineering University of the Basque Country UPV/EHU Bilbao48013 Spain Barcelona Supercomputing Center Barcelona08034 Spain ICREA Catalan Institution for Research and Advanced Studies Barcelona08010 Spain

This study provides an up-to-date assessment of the present-day spatial distribution (2015–2019) and trends (2008–2019) in Spain for eight ozone (O3) metrics relevant for human/ecosystems exposure and regulatory purposes. Main O3 precursors were also analyzed using ground-level observations, satellite observations and emission *** present-day spatial distribution of metrics associated to mid-range to high O3 follows a clear increasing gradient due to the climatic characteristics between the northern (Cantabrian) and the Mediterranean coasts. Conversely, for metrics considering the upper end of the O3 distribution, this gradient tends to attenuate in favor of hotspot regions––the air basins of Madrid, northern Barcelona, the inner Valencian Community (***), and the Sevilla–Guadalquivir Valley––with relevant local/regional O3 *** trends assessment points to a narrowing of O3 distribution, and shows contrasting O3 trends between the hotspot regions: (i) Madrid recorded most of the national O3 upward trends for all the metrics and, in many cases, the highest increasing rates;(ii) Barcelona showed no significant variations along the period;(iii) *** exhibited a mixed variation pattern;whereas (iv) Sevilla was the only city/area in the country with general decreasing trends. These contrasting trends have mainly been attributed to differences in decreases in NOx (in the generally VOC-limited urban areas) in Madrid compared to Barcelona and ***. In Madrid, contributions to NOx emissions from road traffic are significantly higher than in the other two cities, with a decrease in emissions in this sector being the most important, whereas, in Valencia and Barcelona, industrial and shipping emissions might have diluted the effect of the NOx decrease from traffic. The decreasing O3 trends in Sevilla probably resulted from a decrease in NOx in a peculiar urban NOx-limited regime caused by constant VOC contributions from a petrochemi

关键词： Ozone

Analysis of the transmission eigenvalue problem with two conductivity parameters

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Ayala, Rafael Ceja Harris, Isaac Kleefeld, Andreas Pallikarakis, Nikolaos Department of Mathematics Purdue University West LafayetteIN47907 United States Forschungszentrum Jülich GmbH Jülich Supercomputing Centre Wilhelm-Johnen-Straße Jülich52425 Germany University of Applied Sciences Aachen Faculty of Medical Engineering Technomathematics Heinrich-Mußmann-Str. 1 Jülich52428 Germany Department of Mathematics National Technical University of Athens Athens15780 Greece

In this paper, we provide an analytical study of the transmission eigenvalue problem with two conductivity parameters. We will assume that the underlying physical model is given by the scattering of a plane wave for an isotropic scatterer. In previous studies, this eigenvalue problem was analyzed with one conductive boundary parameter where as we will consider the case of two parameters. We will prove the existence and discreteness of the transmission eigenvalues as well as study the dependance on the physical parameters. We are able to prove monotonicity of the first transmission eigenvalue with respect to the parameters and consider the limiting procedure as the second boundary parameter vanishes. Lastly, we provide extensive numerical experiments to validate the theoretical work. © 2022, CC BY.

关键词： Eigenvalues and eigenfunctions

Interpreting a Machine Learning Model for Detecting Gravitational Waves

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Safarzadeh, Mohammadtaher Khan, Asad Huerta, E.A. Wattenberg, Martin Gravitational Astrophysics Laboratory NASA Goddard Space Flight Center United States Department of Physics University of Illinois at Urbana-Champaign Data Science and Learning Division Argonne National Laboratory National Center for Supercomputing Applications University of Illinois at Urbana-Champaign United States Data Science and Learning Division Argonne National Laboratory Department of Computer Science University of Chicago United States School of Engineering and Applied Sciences Harvard University United States

We describe a case study of translational research, applying interpretability techniques developed for computer vision to machine learning models used to search for and find gravitational waves. The models we study are trained to detect black hole merger events in non-Gaussian and non-stationary advanced Laser Interferometer Gravitational-wave Observatory (LIGO) data. We produced visualizations of the response of machine learning models when they process advanced LIGO data that contains real gravitational wave signals, noise anomalies, and pure advanced LIGO noise. Our findings shed light on the responses of individual neurons in these machine learning models. Further analysis suggests that different parts of the network appear to specialize in local versus global features, and that this difference appears to be rooted in the branched architecture of the network as well as noise characteristics of the LIGO detectors. We believe efforts to whiten these "black box" models can suggest future avenues for research and help inform the design of interpretable machine learning models for gravitational wave astrophysics. © 2022, CC BY-NC-ND.

关键词： Gravity waves

A delayed frequency preconditioner approach for speeding-up frequency response computation of structural components 11

学校读者我要写书评

暂无评论

A delayed frequency preconditioner approach for speeding-up ...

11th International Conference on Structural Dynamics, EURODYN 2020

作者： Jenovencio, Guilherme Sivasankar, Arul Saeed, Zeeshan Rixen, Daniel Department of Applied Mechanics Technical University of Munich Boltzmannstr. 15 Garching85785 Germany IT4Innovations National Supercomputing Center Technical University of Ostrava Studentská 6231 Ostrava708 33 Czech Republic Department of Mechanical and Aerospace Engineering Politecnico di Torino Corso Duca degli Abruzzi 24 Turin10129 Italy

ISBN: (纸本)9786188507203

In this work, a delayed frequency preconditioner (DFP) is developed and applied in structural problems for speeding-up the frequency response computation. The challenge of computing the frequency response lies in the computation of the linear system that involves the excitation forces and also the dynamic stiffness which is frequency-dependent. For each frequency, the dynamic stiffness must be updated and a new factorization must be performed, which introduces a high computational cost on the solutions of the linear systems. Alternatively, iterative solver such as GMRES can be applied to avoid the cost of factorization, however they require good preconditioners that are traditionally also frequency-dependent. In the new approach, the dynamic stiffness operator is updated with the frequency whereas the preconditioner is kept constant for a range of frequencies serving as a low-cost preconditioner for the iterative solver. This technique saves computation time because a new factorization is avoided for each frequency point. On the other hand, the effectiveness of the delayed preconditioner is destroyed when the frequency of the dynamic operator is too far away from each other. Therefore, we propose a heuristic approach to update the preconditioner when it is underperforming. The algorithm is tested on structural problems and the results show that this approach can drastically reduce the number of iterations for the computation of the frequency response. © 2020 European Association for Structural Dynamics. All rights reserved.

关键词： Linear systems

A numerical study of third-order equation with time-dependent coefficients: KdVB equation

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Montoya, Cristhian Spa, Carlos School of Applied Sciences and Engineering Universidad EAFIT Medellín Colombia CASE department in the Barcelona Supercomputing Center Plaza Eusebi Güell n3 Barcelona Spain

In this article we present a numerical analysis for a third-order differential equation with non-periodic boundary conditions and time-dependent coefficients, namely, the linear Korteweg-de Vries Burgers equation. This numerical analysis is motived due to the dispersive and dissipative phenomena that government this kind of equations. This work builds on previous methods for dispersive equations with constant coefficients, expanding the field to include a new class of equations which until now have eluded the time-evolving parameters. More precisely, throughout the Legendre-Petrov-Galerkin method we prove stability and convergence results of the approximation in appropriate weighted Sobolev spaces. These results allow to show the role and trade off of these temporal parameters into the model. Afterwards, we numerically investigate the dispersion-dissipation relation for several profiles, further provide insights into the implementation method, which allow to exhibit the accuracy and efficiency of our numerical algorithms. Copyright © 2020, The Authors. All rights reserved.

关键词： Galerkin methods

Contrasting 2008-2019 Trends in Tropospheric Ozone in Spain

学校读者我要写书评

暂无评论

SSRN

SSRN 2022年

作者： Massagué, Jordi Escudero, Miguel Alastuey, Andrés Mantilla, Enrique Monfort, Eliseo Gangoiti, Gotzon García-Pando, Carlos Pérez Querol, Xavier Barcelona08034 Spain Department of Mining Industrial and ICT Engineering Universitat Politècnica de Catalunya - BarcelonaTech UPC Manresa08242 Spain Department of Applied Physics Technological College of Huesca Universidad de Zaragoza Huesca22071 Spain Mediterranean Center for Environmental Studies CEAM Valencia46980 Spain Universitat Jaume I Castellón12006 Spain Faculty of Engineering University of the Basque Country UPV/EHU Bilbao48013 Spain Barcelona Supercomputing Center Barcelona08034 Spain ICREA Catalan Institution for Research and Advanced Studies Barcelona08010 Spain

This study provides an up-to-date assessment of the present-day spatial distribution (2015–2019) and trends (2008–2019) in Spain for eight O3 metrics relevant for human/ecosystems exposure and regulatory purposes. Main O3 precursors were also analyzed using ground-level observations, satellite imagery and emission *** show that the present-day spatial variation of mid-range to high O3 metrics follows a clear increasing climatic gradient between the Cantabrian and Mediterranean coasts. For metrics in the upper end of the O3 distribution, this gradient tends to attenuate in favor of hotspot regions––the air basins of Madrid, (northern) Barcelona, the (inner) Valencian Community (***), and the Sevilla–Guadalquivir Valley––with relevant local/regional O3 *** trends assessment points to a compression of the O3 distribution, and shows contrasting O3 trends between the hotspot regions: (i) Madrid recorded most of the national O3 upward trends for all the metrics and, in many cases, the highest increasing rates;(ii) Barcelona showed almost no variations;(iii) *** exhibited a mixed variation pattern;whereas (iv) Sevilla was the only city/area in the country with general decreasing trends. These contrasting trends have mainly been attributed to differences in decreases in NOx (in the generally VOC-limited urban areas) in Madrid compared to Barcelona and ***. In Madrid, contributions to NOx emissions from road traffic are significantly higher than in the other two cities, with a decrease in emissions in this sector being the most important, whereas, in Valencia and Barcelona, industrial and shipping emissions might have diluted the effect of the NOx decrease from traffic. The decreasing O3 trends in Sevilla probably resulted from a decrease in NOx in a peculiar urban NOx-limited regime caused by constant VOC contributions from a petrochemical plant. Furthermore, differences in agricultural, waste management and other sectors

关键词： Nitrogen oxides

SYNAPSE: An international roadmap to large brain imaging

学校读者我要写书评

暂无评论

Physics Reports 2023年第1期999卷 1-60页

作者： Stampfl, Anton P.J. Liu, Zhongdong Hu, Jun Sawada, Kei Takano, H. Kohmura, Yoshiki Ishikawa, Tetsuya Lim, Jae-Hong Je, Jung-Ho Low, Chian-Ming Teo, Alvin Tok, Eng Soon Tan, Tin Wee Ban, Kenneth Libedinsky, Camilo Tan, Francis Chee Kuan Chen, Kuan-Peng Yang, An-Cheng Chuang, Chao-Chun Chen, Nan-Yow Shih, Chi-Tin Lee, Ting-Kuo Yang, De-Nian Lai, Hsu-Chao Shuai, Hong-Han Cheng, Chang-Chieh Ching, Yu-Tai Li, Chia-Wei Charng, Ching-Che Lo, Chung-Chuan Chiang, Ann-Shyn Recur, Benoit Petibois, Cyril Cheng, Chia-Liang Chen, Hsiang-Hsin Yang, Shun-Min Hwu, Yeukuang Rojviriya, Catleya Rugmai, Supagorn Rujirawat, Saroj Margaritondo, Giorgio Australian Nuclear Science and Technology Organization Lucas Heights 2234 NSW Australia Henan university of Technology Zhengzhou China Shanghai Institute of Applied Physics Chinese Academy of Science Shanghai China RIKEN SPring-8 Center Hyogo 679-5148 Japan Pohang Accelerator Laboratory Pohang University of Science and Technology Pohang Gyeongbuk 37673 South Korea Department of Materials Science and Engineering Pohang University of Science and Technology Gyeongbuk Pohang 37673 South Korea Department of Pharmacology Department of Anaesthesia and Healthy Longevity Research Programme Yong Loo Lin School of Medicine National University of Singapore Singapore School of Chemical and Life Sciences Nanyang Polytechnic Singapore eMaGIC-Lab Department of Physics National University of Singapore Singapore National Supercomputing Center Singapore Department of Psychology The N1 Institute for Health National University of Singapore Singapore Institute of Molecular and Cell Biology A*STAR Singapore Department of Anaesthesia National University Hospital National University Health System Singapore National Center for High-Performance Computing Hsinchu Taiwan Department of Physics Tunghai University Taichung Taiwan Department of Physics National Tsing Hua University Hsinchu Taiwan Institute of Information Science Academia Sinica Taipei Taiwan Department of Computer Science National Yang Ming Chiao Tung University Hsinchu Taiwan Department of Electronics and Electrical Engineering National Yang Ming Chiao Tung University Hsinchu Taiwan Information Technology Service Center National Yang Ming Chiao Tung University Hsinchu Taiwan National Yang Ming Chiao Tung University Hsinchu Taiwan Department of Life Science National Tsing Hua University Hsinchu Taiwan Institute of Systems Neuroscience and Brain Research Center National Tsing Hua University Hsinchu Taiwan Institute of Physics Academia Sinica Taipei Taiwan Department of Physics National Dong Hwa University

Since 2020, synchrotron radiation facilities in several Asia-Pacific countries have been collaborating in a major project called “SYNAPSE” (Synchrotrons for Neuroscience: an Asia-Pacific Scientific Enterprise). They use x-ray imaging to attack in a coordinated fashion one of the major issues in modern science: the structure of animal and human brains, including neurons and connections. The objective is to develop Google-like maps also including detailed structural and functional information for selected regions of interest. The sheer mass of data needed for the objective poses huge problems for the acquisition, processing, storage and use of images. In order to complete the task within a reasonable time, the key element of the SYNAPSE strategy is the parallel and coordinated work of several facilities on the same specimens. This article reviews different aspects of the enterprise, including the foundations of synchrotron radiation, coherence and of its role in advanced imaging, electron accelerators, x-ray optics and detectors. This will provide the foundation for an extensive presentation of the different components of SYNAPSE, with an overview of results already obtained within the consortium. © 2022

关键词： Brain mapping Phase contrast Radiology supercomputing Synchrotron X-rays

Simulating quantum dynamics: Evolution of algorithms in the HPC context

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Meyerov, I. Liniov, A. Ivanchenko, M. Denisov, S. Department of Software and Supercomputing Technologies Lobachevsky University Nizhny Novgorod603950 Russia Department of Software Engineering Lobachevsky University Nizhny Novgorod603950 Russia Department of Applied Mathematics Lobachevsky University Nizhny Novgorod603950 Russia Department of Computer Science Oslo Metropolitan University OsloN-0130 Norway

Due to complexity of the systems and processes it addresses, the development of computational quantum physics is influenced by the progress in computing technology. Here we overview the evolution, from the late 1980s to the current year 2020, of the algorithms used to simulate dynamics of quantum systems. We put the emphasis on implementation aspects and computational resource scaling with the model size and propagation time. Our mini-review is based on a literature survey and our experience in implementing different types of algorithms. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum optics

REAL-TIME GEOINFORMATION SYSTEMS TO IMPROVE THE QUALITY, SCALABILITY, AND COST OF INTERNET OF THINGS FOR AGRI-ENVIRONMENT RESEARCH

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Runck, Bryan C. Schulz, Bobby Bishop, Jeff Carlson, Nathan Chantigian, Bryan Deters, Gary Erdmann, Jesse Ewing, Patrick M. Felzan, Michael Fu, Xiao Greyling, Jan Hogan, Christopher J. Hollman, Andrew Joglekar, Ali Junker, Kris Kantar, Michael Kaunda, Lumbani Krishna, Mohana Lynch, Benjamin Marchetto, Peter Marsolek, Megan McKay, Troy Morris, Brad Niaghi, Ali Rashid Pamulaparthy, Keerthi Pardey, Philip Piotrowski, Ann Poudyal, Christina Prather, Tom Raghavan, Barath Reiter, Maggie Rosen, Lucas Salazar, Benjamin Scobbie, Andrew Sharma, Vasudha Silverstein, Kevin A.T. Singh, Gurparteet Strock, Jeff Subedi, Samikshya Tang, Evan Turturillo, Gianna Watkins, Eric Webster, Blake Wilgenbusch, James GEMS Informatics Center University of Minnesota Twin Cities United States Department of Geography Environment and Society University of Minnesota Twin Cities United States Minnesota Supercomputing Institute University of Minnesota United States Department of Electrical Engineering University of Minnesota Twin Cities United States Department of Applied Economics University of Minnesota Twin Cities United States Department of Horticultural Science University of Minnesota Twin Cities United States Department of Computer Science University of Southern California United States Sensing Inc. Conservify Graphspan LLC USDA-ARS Food Systems Research Unit BurlingtonVT05405 United States Amazon United States Department of Soil Water and Climate University of Minnesota Twin Cities United States Department of Computer Science and Engineering University of Minnesota Twin Cities United States Departmnet of Agricultural Education Communication and Marketing University of Minnesota Twin Cities United States Benson Hill United States Southwest Research and Outreach Center University of Minnesota Twin Cities United States Code Weavers Department of Mechanical Engineering University of Minnesota Twin Cities United States University of Hawaii at Manoa HonoluluHI United States Minnesota Agricultural Experiment Station University of Minnesota Twin Cities United States Sunday Stellenbosch AgroInformatics Initiative Stellenbosch University South Africa Ameriprise Financial Services LLC Optum University of Minnesota Twin Cities United States

With the increasing emphasis on machine learning and artificial intelligence to drive knowledge discovery in the agricultural sciences, spatial internet of things (IoT) technologies have become increasingly important for collecting real-time, high resolution data for these models. However, managing large fleets of devices while maintaining high data quality remains an ongoing challenge as scientists iterate from prototype to mature end-to-end applications. Here, we provide a set of case studies using the framework of technology readiness levels for an open source spatial IoT system. The spatial IoT systems underwent 3 major and 14 minor system versions, had over 2,727 devices manufactured both in academic and commercial contexts, and are either in active or planned deployment across four continents. Our results show the evolution of a generalizable, open source spatial IoT system designed for agricultural scientists, and provide a model for academic researchers to overcome the challenges that exist in going from one-off prototypes to thousands of internet-connected devices. © 2024, CC BY-NC-ND.

关键词： Internet of things