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作者： Abdelzaher, Tarek An, Jisun Bazzi, Marya Blackburn, Jeremy Kursuncu, Ugur Mejova, Yelena Rappaz, Jérémie Saggion, Horacio Smeros, Panayiotis Wijeratne, Sanjaya Yu, Ning Department of Computer Science University of Illinois at Urbana-Champaign Urbana-ChampaignIL United States Qatar Computing research institute Hamad Bin Khalifa University Ar-rayyan Qatar Alan Turing institute London United Kingdom Department of Computer Science Binghamton University BinghamtonNY United States Artificial intelligence institute University of South Carolina ColumbiaSC United States Institute for Scientific Interchange Foundation turin Italy École Polytechnique Fédérale de Lausanne Lausanne Switzerland Department of information and Communication technologies Universitat Pompeu Fabra Barcelona Spain Holler technologies inc. San MateoCA United States Artificial intelligence/ Machine Learning Accelerator at Leidos restonVA United States

The workshop program of the Association for the Advancement of Artificial Intelligence's Fourteenth International Conference on Web and Social Media was held June 8 to 20, 2020. The conference venue, which had originally been Atlanta, Georgia, USA, had to be revamped into a virtual edition, due to the 2019 Corona Virus Disease pandemic. There were five full-day workshops in the program. They included Emoji Understanding and Applications in Social Media (W1), Social Sensing: Narrative Analysis on Social Media (W2), News and Public Opinion (W3), Cyber Social Threats (W4), and Mediate: Social and News Media Misinformation (W5). This report contains summaries of all five workshops. Copyright © 2020, Association for the Advancement of Artificial Intelligence. All rights reserved. ISSN 0738-4602

关键词： Social aspects

A Visual Analytics Framework for Distributed Data Analysis Systems

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A Visual Analytics Framework for Distributed Data Analysis S...

IEEE International Conference on Big Data

作者： Abdullah-Al-Raihan Nayeem Mohammed Elshambakey Todd Dobbs Huikyo Lee Daniel Crichton Yimin Zhu Chanachok Chokwitthaya William J. Tolone Isaac Cho College of Computing and Informatics University of North Carolina at Charlotte Charlotte United States City of Scientific Research and Technological Applications Alexandria Egypt Computer Science University of North Carolina at Greensboro Greensboro United States Jet Propulsion Laboratory California Institute of Technology Pasadena United States Construction Management Louisiana State University Rouge United States Computer Science Utah State University Logan United States

ISBN: (纸本)9781665445993

This paper proposes a visual analytics framework that addresses the complex user interactions required through a command-line interface to run analyses in distributed data analysis systems. The visual analytics framework facilitates the user to manage access to the distributed servers, incorporate data from the source, run data-driven analysis, monitor the progress, and explore the result using interactive visualizations. We provide a user interface embedded with generalized functionalities and access protocols and integrate it with a distributed analysis system. To demonstrate our proof of concept, we present two use cases from the earth science and Sustainable Human Building Ecosystem research domain.

关键词： Data analysis Visual analytics Ecosystems Data visualization Distributed databases Configuration management Geoscience

An improved N-bit to N-bit reversible Haar-like transform

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An improved N-bit to N-bit reversible Haar-like transform

Pacific Conference on computer Graphics and Applications

作者： J.G. Senecal P. Lindstrom M.A. Duchaineau K.I. Joy Inst. for Sci. Comput. Res. Lawrence Livermore Nat. Lab. CA USA Center for Applied Scientific Computing Lawrence Livemore National Laboratory USA Institute for Data Analysis and Visualization Computer Science Department University of California Davis USA

We introduce the piecewise-linear Haar (PLHaar) transform, a reversible n-bit to n-bit transform that is based on the Haar wavelet transform. PLHaar is continuous, while all current n-bit to n-bit methods are not, and is therefore uniquely usable with both lossy and lossless methods (e.g. image compression). PLHaar has both integer and continuous (i.e. non-discrete) forms. By keeping the coefficients to n bits PLHaar is particularly suited for use in hardware environments where channel width is limited, such as digital video channels and graphics hardware.

关键词： Wavelet transforms Continuous wavelet transforms Hardware Dynamic range Image coding scientific computing Image reconstruction Laboratories Data analysis Data visualization

A Landscape-Aware Differential Evolution for Multimodal Optimization Problems

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arXiv 2024年

作者： Lin, Guo-Yun Chen, Zong-Gan Liu, Chuanbin Jiang, Yuncheng Kwong, Sam Zhang, Jun Zhan, Zhi-Hui School of Computer Science South China Normal University Guangzhou510631 China The Center for Scientific Research and Development in Higher Education Institutes Ministry of Education China The Department of Computing and Decision Science Lingnan University Hong Kong The College of Artificial Intelligence Nankai University Tianjin300350 China The Hanyang University ERICA 15588 Korea Republic of

How to simultaneously locate multiple global peaks and achieve certain accuracy on the found peaks are two key challenges in solving multimodal optimization problems (MMOPs). In this paper, a landscape-aware differential evolution (LADE) algorithm is proposed for MMOPs, which utilizes landscape knowledge to maintain sufficient diversity and provide efficient search guidance. In detail, the landscape knowledge is efficiently utilized in the following three aspects. First, a landscape-aware peak exploration helps each individual evolve adaptively to locate a peak and simulates the regions of the found peaks according to search history to avoid an individual locating a found peak. Second, a landscape-aware peak distinction distinguishes whether an individual locates a new global peak, a new local peak, or a found peak. Accuracy refinement can thus only be conducted on the global peaks to enhance the search efficiency. Third, a landscape-aware reinitialization specifies the initial position of an individual adaptively according to the distribution of the found peaks, which helps explore more peaks. The experiments are conducted on 20 widely-used benchmark MMOPs. Experimental results show that LADE obtains generally better or competitive performance compared with seven well-performed algorithms proposed recently and four winner algorithms in the IEEE CEC competitions for multimodal optimization. Copyright © 2024, The Authors. All rights reserved.

关键词： Optimization algorithms

Solving bang-bang problems using the immersed interface method and integer programming

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arXiv 2021年

作者： Vogt, Ryan H. Strikwerda, Sarah Department of Mathematics North Carolina State University RaleighNC27695 United States Mathematics and Computer Science Division Argonne National Laboratory LemontIL60439 United States Center for Applied Scientific Computing Lawrence Livermore National Laboratory LivermoreCA94550 United States

In this paper we study numerically solving optimal control problems with bang-bang control functions. We present a formal Lagrangian approach for solving the optimal control problem, and address difficulties encountered when numerically solving the state and adjoint equations by using the immersed interface method. We note that our numerical approach does not approximate the discontinuous control function with smooth functions, instead we solve the true bang-bang optimal control problem. Our approach for solving the optimal control problem uses an adjoint-based gradient. We use the gradient in our first-order trust-region method to generate a local minimizing control. We present detailed numerical results to demonstrate the effectiveness of our method. © 2021, CC BY.

关键词： Constrained optimization

Learning interface conditions in domain decomposition solvers 22

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Learning interface conditions in domain decomposition solver...

Proceedings of the 36th International Conference on Neural Information Processing Systems

作者： Ali Taghibakhshi Nicolas Nytko Tareq Zaman Scott MacLachlan Luke Olson Matthew West Mechanical Science and Engineering University of Illinois Urbana-Champaign Urbana IL Computer Science University of Illinois Urbana-Champaign Urbana IL Scientific Computing Program Memorial University of Newfoundland and Labrador St. John's NL Canada Mathematics and Statistics Memorial University of Newfoundland and Labrador St. John's NL Canada

ISBN: (纸本)9781713871088

Domain decomposition methods are widely used and effective in the approximation of solutions to partial differential equations. Yet the optimal construction of these methods requires tedious analysis and is often available only in simplified, structured-grid settings, limiting their use for more complex problems. In this work, we generalize optimized Schwarz domain decomposition methods to unstructured-grid problems, using Graph Convolutional Neural Networks (GCNNs) and unsupervised learning to learn optimal modifications at subdomain interfaces. A key ingredient in our approach is an improved loss function, enabling effective training on relatively small problems, but robust performance on arbitrarily large problems, with computational cost linear in problem size. The performance of the learned linear solvers is compared with both classical and optimized domain decomposition algorithms, for both structured- and unstructured-grid problems.

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Exponential time differencing for the tracer equations appearing in primitive equation ocean models

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arXiv 2019年

作者： Calandrini, Sara Pieper, Konstantin Gunzburger, Max D. Department of Scientific Computing Florida State University TallahasseeFL32306 United States Computer Science and Mathematics Division Oak Ridge National Laboratory One Bethel Valley Road P.O. Box 2008 MS-6211 Oak RidgeTN37831 United States

The tracer equations are part of the primitive equations used in ocean modeling and describe the transport of tracers, such as temperature, salinity or chemicals, in the ocean. Depending on the number of tracers considered, several equations may be added to and coupled to the dynamics system. In many relevant situations, the time-step requirements of explicit methods imposed by the transport and mixing in the vertical direction are more restrictive than those for the horizontal, and this may cause the need to use very small time steps if a fully explicit method is employed. To overcome this issue, we propose an exponential time differencing (ETD) solver where the vertical terms (transport and diffusion) are treated with a matrix exponential, whereas the horizontal terms are dealt with in an explicit way. We investigate numerically the computational speed-ups that can be obtained over other semi-implicit methods, and we analyze the advantages of the method in the case of multiple tracers. Copyright © 2019, The Authors. All rights reserved.

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Parallel PDE-based simulations using the common component architecture

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Lecture Notes in Computational science and Engineering 2006年 51卷 327-381页

作者： McInnes, Lois Curfman Allan, Benjamin A. Armstrong, Robert Benson, Steven J. Bernholdt, David E. Dahlgren, Tamara L. Diachin, Lori Freitag Krishnan, Manojkumar Kohl, James A. Walter Larson, J. Lefantzi, Sophia Nieplocha, Jarek Norris, Boyana Parker, Steven G. Ray, Jaideep Zhou, Shujia Mathematics and Computer Science Division Argonne National Laboratory Argonne IL United States Livermore CA United States Computer Science and Mathematics Division Oak Ridge National Laboratory Oak Ridge TN United States Center for Applied Scientific Computing Lawrence Livermore National Laboratory Livermore CA United States Computational Sciences and Mathematics Pacific Northwest National Laboratory Richland WA United States Reacting Flow Research SNL Livermore CA United States Scientific Computing and Imaging Institute University of Utah Salt Lake City UT United States Advanced Software R and D SNL Livermore CA United States Northrop Grumman Corporation Information Technology Sector Chantilly VA United States

ISBN: (纸本)9783540290766

The complexity of parallel PDE-based simulations continues to increase as multimodel, multiphysics, and multi-institutional projects become widespread. A goal of component - based software engineering in such large-scale simulations is to help manage this complexity by enabling better interoperability among various codes that have been independently developed by different groups. The Common Component Architecture (CCA) Forum is defining a component architecture specification to address the challenges of high-performance scientific computing. In addition, several execution frameworks, supporting infrastructure, and general-purpose components are being developed. Furthermore, this group is collaborating with others in the high-performance computing community to design suites of domain-specific component interface specifications and underlying implementations. © Springer-Verlag Berlin Heidelberg 2006.

关键词： Multiphysics

CDOpt: A Python Package for a Class of Riemannian Optimization

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arXiv 2022年

作者： Xiao, Nachuan Hu, Xiaoyin Liu, Xin Toh, Kim-Chuan The Institute of Operations Research and Analytics National University of Singapore Singapore School of Computer and Computing Science Hangzhou City University Hangzhou China Academy of Edge Intelligence Hangzhou City University Gongshu Hangzhou China State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences University of Chinese Academy of Sciences China Department of Mathematics Institute of Operations Research and Analytics National University of Singapore Singapore

Optimization over an embedded submanifold defined by equality constraints c(x) = 0 has attracted much interest over the past few decades due to its wide applications in various areas, including computer vision, signal processing, numerical linear algebra, and deep learning. For solving such problems, many related optimization packages have been developed based on Riemannian optimization approaches, which rely on some basic geometrical materials of Riemannian manifolds, including Riemannian gradients, retractions, vector transports, etc. These geometrical materials can be challenging to determine in general. In fact, existing packages only accommodate a few well-known manifolds whose geometrical materials are more easily accessible. For other manifolds that are not contained in these packages, the users have to develop the geometric materials by themselves. In addition, it is not always tractable to adapt the advanced features from various state-of-the-art unconstrained optimization solvers to Riemannian optimization approaches. Here we introduce a user-friendly Python package, CDOpt (available at https: //***/ under BSD 3-clause license), for solving a class of Riemannian optimization problems. CDOpt is designed to complement existing Riemannian optimization packages by transforming Riemannian optimization problems into their unconstrained counterparts through the constraint dissolving approach. We prove that the when the penalty parameter in the constraint dissolving approach is sufficiently large, Riemannian optimization problems and their unconstrained counterparts are equivalent. Therefore, solving Riemannian optimization problems through CDOpt can directly benefit from various existing solvers and the rich expertise gained over the past few decades for unconstrained optimization. Moreover, all the computations in CDOpt related to any manifold in question are conducted through its constraints expression, hence users can easily define new manifolds in

关键词： Constrained optimization

Temperature-Dependent Hydrogen Modulations of Ultra-Scaled a-IGZO Thin Film Transistor Under Gate Bias Stress

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IEEE Open Journal of Nanotechnology

IEEE Open Journal of Nanotechnology 2024年 5卷 9-16页

作者： Aslam, Muhammad Chang, Shu-Wei Chuang, Min-Hui Chen, Yi-Ho Lee, Yao-Jen Li, Yiming Parallel and Scientific Computing Laboratory National Yang Ming Chiao Tung University Hsinchu300093 Taiwan Electrical Engineering and Computer Science International Graduate Program National Yang Ming Chiao Tung University Hsinchu300093 Taiwan Department of Electrical Engineering National Cheng Kung University Tainan701401 Taiwan Institute of Communications Engineering National Yang Ming Chiao Tung University Hsinchu300093 Taiwan Graduate Degree Program of College of Electrical and Computer Engineering National Yang Ming Chiao Tung University Hsinchu300093 Taiwan Institute of Pioneer Semiconductor Innovation National Yang Ming Chiao Tung University Hsinchu300093 Taiwan Institute of Biomedical Engineering National Yang Ming Chiao Tung University Hsinchu300093 Taiwan Department of Electronics and Electrical Engineering National Yang Ming Chiao Tung University Hsinchu300093 Taiwan

Recently, a-IGZO has advanced toward the next-generation electronics system because of its compatibility with complementary metal oxide semiconductor (CMOS) and back-end-of-line (BOEL) based systems. A systematic electrical characterization of a-IGZO TFT related to reliability issues, such as positive bias temperature stress (PBTS) and negative bias temperature stress (NBTS), would entitle its integration into novel electronics systems. Unexpectedly, PBTS is characterized by the transition of positive Vth shift to negative Vth shift (ΔVth, the positive shift followed by the stress and temperature activated negative shift). This transition is attributed to charge trapping/trap-site generations and hydrogen migration to the active layer. The ΔVth shift mechanism depends on the temperature and voltage stress. On the other hand, a negative ΔVth shift has been observed during the NBTS operation and could be attributed to the hole trapping at the interface of GI/IGZO. An effective suppression of the gate leakage current has also been observed during reliability tests. Simulation results reveal a pronounced potential at the edges of source and drain regions, and considered the origin of hydrogen migration into the IGZO layer. Thermal image results also reveal the strong temperature/potential distribution at the edges of the source/drain regions, indorsing the simulation results. © 2020 IEEE.

关键词： Oxide semiconductors