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arXiv 2019年

作者： Alards, Kim M.J. Kunnen, Rudie P.J. Stevens, Richard J.A.M. Lohse, Detlef Toschi, Federico Clercx, Herman J.H. Fluid Dynamics Laboratory and J.M. Burgers Center for Fluid Dynamics Department of Applied Physics Eindhoven University of Technology P.O. Box 513 Eindhoven5600 MB Netherlands Physics of Fluids Group Max Planck Center for Complex Fluid Dynamics J.M. Burgers Center for Fluid Dynamics and MESA+ Research Institute Department of Science and Technology University of Twente P.O. Box 217 Enschede7500 AE Netherlands Max Planck Institute for Dynamics and Self-Organization Am Fassberg 17 Göttingen37077 Germany Centre of Analysis Scientific Computing and Applications W&I Department of Mathematics and Computer Science Eindhoven University of Technology P.O. Box 513 Eindhoven5600 MB Netherlands Istituto per le Applicazioni del Calcolo Consiglio Nazionale delle Ricerche Via dei Taurini 19 Rome00185 Italy

In Rayleigh–Bénard convection (RBC) for fluids with Prandtl number Pr 1, rotation beyond a critical (small) rotation rate is known to cause a sudden enhancement of heat transfer which can be explained by a change in the character of the boundary layer (BL) dynamics near the top and bottom plates of the convection cell. Namely, with increasing rotation rate, the BL signature suddenly changes from Prandtl–Blasius type to Ekman type. The transition from a constant heat transfer to an almost linearly increasing heat transfer with increasing rotation rate is known to be sharp and the critical Rossby number Roc occurs typically in the range 2.3 Roc 2.9 (for Rayleigh number Ra = 1.3×109, Pr = 6.7, and a convection cell with aspect ratio Γ = HD = 1, with D the diameter and H the height of the cell). The explanation of the sharp transition in the heat transfer points to the change in the dominant flow structure. At 1/Ro . 1/Roc (slow rotation), the well-known large-scale circulation (LSC) is found: a single domain-filling convection roll made up of many individual thermal plumes. At 1/Ro 1/Roc (rapid rotation), the LSC vanishes and is replaced with a collection of swirling plumes that align with the rotation axis. In this paper, by numerically studying Lagrangian acceleration statistics, related to the small-scale properties of the flow structures, we reveal that this transition between these different dominant flow structures happens at a second critical Rossby number, Roc2 ≈ 2.25 (different from Roc1 ≈ 2.7 for the sharp transition in the Nusselt number Nu;both values for the parameter settings of our present numerical study). When statistical data of Lagrangian tracers near the top plate are collected, it is found that the root-mean-square (rms) values and the kurtosis of the horizontal acceleration of these tracers show a sudden increase at Roc2. To better understand the nature of this transition we compute joint statistics of the Lagrangian velocity and acceleration of f

关键词： Flow structure

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Towards detailed material deformation patterns in the hypervelocity impacts of laminated plates with smoothed particle hydrodynamics

Towards detailed material deformation patterns in the hyperv...

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ASME 2016 Pressure Vessels and Piping Conference, PVP 2016

作者： Zisis, Iason Van Der Linden, Bas Giannopapa, Christina Koren, Barry Dam, Jacques Centre for Analysis Scientific Computing and Applications Department of Mathematics and Computer Science TU Eindhoven Eindhoven Netherlands Energy Technology Department of Mechanical Engineering TU Eindhoven Eindhoven Netherlands

ISBN: (纸本)9780791850404

Hypervelocity impacts onto the outer structure of spacecraft induce shock waves, which in case of multimaterial structures interact with the material interfaces. This interaction is expected to produce different deformation patterns for laminates compared to the patterns appearing for materials with homogeneous density. In order to exhibit these different features and to show that the Smoothed Particle Hydrodynamics computational method is capable of describing them, a numerical hypervelocity impact experiment is performed for three plates. The first one is a laminate, with discontinuous density and material parameters, the second is a simple homogenized version of the laminate and the last is a monolithic metal plate. Copyright © 2016 by ASME.

关键词： Shock waves

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Geometry of tracer trajectories in rotating turbulent flows

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Physical Review Fluids 2017年第4期2卷 044601-044601页

作者： Kim M. J. Alards Hadi Rajaei Lorenzo Del Castello Rudie P. J. Kunnen Federico Toschi Herman J. H. Clercx Fluid Dynamics Laboratory Department of Applied Physics Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands Istituto Sistemi Complessi Consiglio Nazionale delle Ricerche UOS Sapienza 00185 Rome Italy Centre of Analysis Scientific Computing and Applications W&I Department of Mathematics and Computer Science Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands Istituto per le Applicazioni del Calcolo Consiglio Nazionale delle Ricerche Via dei Taurini 19 00185 Rome Italy

The geometry of passive tracer trajectories is studied in two different types of rotating turbulent flows; rotating Rayleigh-Bénard convection (RBC; experiments and direct numerical simulations) and rotating electromagnetically forced turbulence (EFT; experiments). This geometry is fully described by the curvature and torsion of trajectories, and from these geometrical quantities we can subtract information on the typical flow structures at different rotation rates. Previous studies, focusing on nonrotating homogeneous isotropic turbulence (HIT), show that the probability density functions (PDFs) of curvature and torsion reveal pronounced power laws. However, the set-ups studied here involve inhomogeneous turbulence, and in RBC the flow near the horizontal plates is definitely anisotropic. We investigate how the typical shapes of the curvature and torsion PDFs, including the pronounced scaling laws, are influenced by this level of anisotropy and inhomogeneity and how this effect changes with rotation. A first effect of rotation is observed as a shift of the curvature and torsion PDFs towards higher values in the case of RBC and towards lower values in the case of EFT. This shift is related to the length scale of typical vortical structures that decreases with rotation in RBC, but increases with rotation in EFT, explaining the opposite shifts of the curvature (and torsion) PDFs. A second remarkable observation is that in RBC the HIT scaling laws are always recovered, as long as the boundary layer (BL) is excluded. This suggests that these scaling laws are very robust and hold as long as we measure in the turbulent bulk. In the BL of the RBC cell, however, the scaling deviates from the HIT prediction for lower rotation rates. This scaling behavior is found to be consistent with the coupling between the boundary layer dynamics and the bulk flow, which changes under rotation. In particular, it is found that the active coupling of the Ekman-type boundary layer with the b

关键词： Rayleigh-Bénard convection Turbulence Convection

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Caffeine: Towards uniformed representation and acceleration for deep convolutional neural networks

Caffeine: Towards uniformed representation and acceleration ...

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IEEE International Conference on computer-Aided Design

作者： Chen Zhang Zhenman Fang Peipei Zhou Peichen Pan Jason Cong Center for Energy-Efficient Computing and Applications Peking University Beijing China Falcon-computing Inc. USA UCLA Computer Science Department University of California Los Angeles USA UCLA Peking University and the chief scientific advisor at Falcon Computing Solutions

ISBN: (纸本)9781509034215

With the recent advancement of multilayer convolutional neural networks (CNN), deep learning has achieved amazing success in many areas, especially in visual content understanding and classification. To improve the performance and energy-efficiency of the computation-demanding CNN, the FPGA-based acceleration emerges as one of the most attractive alternatives. In this paper we design and implement Caffeine, a hardware/software co-designed library to efficiently accelerate the entire CNN on FPGAs. First, we propose a uniformed convolutional matrix-multiplication representation for both computation-intensive convolutional layers and communication-intensive fully connected (FCN) layers. Second, we design Caffeine with the goal to maximize the underlying FPGA computing and bandwidth resource utilization, with a key focus on the bandwidth optimization by the memory access reorganization not studied in prior work. Moreover, we implement Caffeine in the portable high-level synthesis and provide various hardware/software definable parameters for user configurations. Finally, we also integrate Caffeine into the industry-standard software deep learning framework Caffe. We evaluate Caffeine and its integration with Caffe by implementing VGG16 and AlexNet network on multiple FPGA platforms. Caffeine achieves a peak performance of 365 GOPS on Xilinx KU060 FPGA and 636 GOPS on Virtex7 690t FPGA. This is the best published result to our best knowledge. We achieve more than 100× speedup on FCN layers over previous FPGA accelerators. An end-to-end evaluation with Caffe integration shows up to 7.3× and 43.5× performance and energy gains over Caffe on a 12-core Xeon server, and 1.5× better energy-efficiency over the GPU implementation on a medium-sized FPGA (KU060). Performance projections to a system with a high-end FPGA (Virtex7 690t) shows even higher gains.

关键词： Field programmable gate arrays Acceleration Bandwidth Machine learning Convolution Graphics processing units Kernel

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SSC: Cloud-based data stream management in distributed environments

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International Journal of High Performance computing and Networking 2016年第3期9卷 171-189页

作者： Ong, Kok-Leong Goscinski, Andrzej Han, Yuzhang Brezany, Peter Tari, Zahir Yan, Lei La Trobe Business School La Trobe University Australia School of Information Technology Deakin University Australia Department of Computer Science Duke University DurhamNC United States Research Group Scientific Computing Faculty of Computer Science University of Vienna Nordbergstrasse 15/C/315 Vienna Austria School of Computer Science RMIT University Australia Spatial Information Integration and Its Applications Laboratory Peking University Beijing China

Stream-oriented applications account for one of the major types of today's computing practices. They deal with high-speed data streams. When it comes to stream-oriented distributed systems, some challenges arise: for one thing, processing capability of a single compute node might become the bottleneck of the entire system. For another, transmitting streams among physically dispersed nodes could incur both communication overhead and instability of a distributed application. In this paper, we discuss the potential of using cloud technology to respond to various challenges faced by stream-oriented distributed systems. We introduce our idea of a special cloud, the scientific streaming cloud (SSC), which supports stream management in distributed environments. We also present our design of a language and an algorithm which are used on the SSC to describe and optimise stream-related tasks, respectively. Furthermore, we demonstrate our prototype implementation and a real-world application of the SSC. © 2016 Inderscience Enterprises Ltd.

关键词： Environmental management

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Making advanced scientific algorithms and big scientific data management more accessible 14

Making advanced scientific algorithms and big scientific dat...

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Computational Imaging XIV 2016

作者： Venkatakrishnan, S.V. Mohan, K. Aditya Beattie, Keith Correa, Joaquin Dart, Eli Deslippe, Jack R. Hexemer, Alexander Krishnan, Harinarayan MacDowell, Alastair A. Marchesini, Stefano Patton, Simon J. Perciano, Talita Sethian, James A. Stromsness, Rune Tierney, Brian L. Tull, Craig E. Ushizima, Daniela Parkinson, Dilworth Y. Center for Advanced Mathematics for Energy Research Applications Lawrence Berkeley National Lab BerkeleyCA94720 United States Advanced Light Source Lawrence Berkeley National Lab BerkeleyCA94720 United States School of Electrical and Computer Engineering Purdue University PurdueIN47907 United States Computational Research Division Lawrence Berkeley National Lab BerkeleyCA94720 United States National Energy Research Scientific Computing Center BerkeleyCA94720 United States Energy Sciences Network BerkeleyCA94720 United States Department of Mathematics UC Berkeley BerkeleyCA94720 United States

Synchrotrons such as the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory are user facilities - they are sources of extremely bright X-ray beams, and scientists come from all over the world to perform experiments that require these beams. As the complexity of experiments has increased, and the size and rates of data sets has exploded, managing, analyzing and presenting the data collected at synchrotrons has been an increasing challenge. The ALS has partnered with high performance computing, fast networking, and applied mathematics groups to create a"super-facility", giving users simultaneous access to the experimental, computational, and algorithmic resources to overcome this challenge. This combination forms an efficient closed loop, where data despite its high rate and volume is transferred and processed, in many cases immediately and automatically, on appropriate compute resources, and results are extracted, visualized, and presented to users or to the experimental control system, both to provide immediate insight and to guide decisions about subsequent experiments during beam-time. In this paper, We will present work done on advanced tomographic reconstruction algorithms to support users of the 3D micron-scale imaging instrument (Beamline 8.3.2, hard X-ray micro-tomography). © 2016 Society for Imaging Science and Technology.

关键词： Tomography

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Fluid structure interaction in HPC multi-code coupling

Fluid structure interaction in HPC multi-code coupling

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作者： Cajas, J.C. Zavala, M. Houzeaux, G. Casoni, E. Vázquez, M. Moulinec, C. Fournier, Y. Computer Applications for Science and Engineering Barcelona Supercomputing Center Spain Scientific Computing Department Science and Technology Facilities Council Daresbury Laboratory Warrington United Kingdom Research and Development Électricité de France Chatou France

Fluid structure interaction (FSI) problems are of great interest in many applied fields such as aerodynamics, renewable energy generation, nuclear energy generation, vehicles design and biophysical systems research. This kind of problems can be addressed using a monolithic or a staggered approach. The monolithic scheme usually provides robustness and stability in the simulation process but involves extensive code rewriting and is usually less flexible than the staggered approach. The later usually suffers instability in the coupling algorithm but it allows to reuse previously existing code for the physical components of the problem. Extreme-scaling codes for computational fluid dynamics (CFD) and computational solid dynamics (CSD) have been developed for high end machines through the years, and have proven to run efficiently on the most powerful supercomputing infrastructure available. This makes the staggered multi-code coupling approach particularly attractive for FSI simulations on high performance computing (HPC) systems. However, besides the physical difficulties belonging to the FSI simulations, multi-code coupling poses its own computational challenges, as it involves extra communication between two a priori independent parallel applications. This creates an extra level of load imbalance and synchronization points that have to be carefully considered in order to maintain the efficiency of the separated codes, as well as of the whole coupling. In this paper, a staggered approach for FSI problems is presented. Two instances of the same extreme-scale code are used, Alya-Nastin for the CFD simulation and Alya-solidz for the CSD simulation. Characteristics of the parallel code coupling are presented and a validation test case is considered. © Civil-Comp Press, 2015.

关键词： Computational fluid dynamics

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Foreword

Proceedings of the 2016 International Conference on Image Pr...

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Proceedings of the 2016 International Conference on Image Processing, computer Vision, and Pattern Recognition, IPCV 2016 2016年

作者： Abd-Wahab, Mohd Helmy Al-Bakry, Abbas Al-Holou, Nizar Arabnia, Hamid R. Bhattacharya, Mahua Martinez Castillo, Juan Jose Daimi, Kevin Deligiannidis, Leonidas Djoudi, Lamia Atma Duong, Trung Eshaghian-Wilner, Mary Mehrnoosh Gravvanis, George A. Huang, Ruizhu Jandieri, George Kim, Byung-Gyu Kim, Tai-hoon Korovin, Iakov Lai, Guoming Lee, Hyo Jong Bin Mansor, Muhammad Naufal Marsh, Andrew Mostafaeipour, Ali Park, James J. Patil, Shashikant Ponalagusamy, R. Schaefer, Gerald Singh, Akash Solo, Ashu M.G. Swee, Sim Kok Thomas, Jaya Tinetti, Fernando G. Vladimir, Hahanov Wang, Shiuh-Jeng Yang, Mary Yoe, Hyun You, Jane Zhao, Wenbing Department of Computer Engineering University Tun Hussein Onn Malaysia Malaysia University of IT and Communications Baghdad Iraq Electrical and Computer Engineering Department IEEE/SEM-Computer Chapter University of Detroit Mercy DetroitMI United States University of Georgia United States ABV Indian Institute of Information Technology and Management MHRD Government of India India Acantelys Alan Turing Nikola Tesla Research Group and GIPEB Universidad Nacional Abierta Venezuela Computer Science and Software Engineering Programs Department of Mathematics Computer Science and Software Engineering University of Detroit Mercy DetroitMI United States Department of Computer Information Systems Wentworth Institute of Technology BostonMA United States Synchrone Technologies France Rutgers University State University of New Jersey New Jersey United States University of Southern California California United States Electrical Engineering University of California Los Angeles Los Angeles [UCLA CA United States Advanced Scientific Computing Applied Math and Applications Research Group Applied Mathematics and Numerical Computing and Department of ECE School of Engineering Democritus University of Thrace Xanthi Greece Texas Advanced Computing Center University of Texas AustinTX United States Georgian Technical University Tbilisi Georgia Institute of Cybernetics Georgian Academy of Science Georgia Multimedia Processing CommunicationsLab.[MPCL Department of Computer Science and Engineering College of Engineering SunMoon University Korea Republic of School of Information and Computing Science University of Tasmania Australia Southern Federal University Russia Computer Science and Technology Sun Yat-Sen University Guangzhou China Center for Advanced Image and Information Technology Division of Computer Science and Engineering Chonbuk National University Korea Republic of Faculty of Engineering Technology Kampus Uniciti Alam Universiti Malaysia Perlis UniMAP Malaysi

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Solving the Klein-Gordon equation using Fourier spectral methods: A benchmark test for computer performance 23

Solving the Klein-Gordon equation using Fourier spectral met...

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23rd High Performance computing Symposium, HPC 2015, Part of the 2015 Spring Simulation Multi-Conference, SpringSim 2015

作者： Aseeri, S. Batrašev, O. Icardi, M. Leu, B. Liu, A. Li, N. Muite, B.K. Müller, E. Palen, B. Quell, M. Servat, H. Sheth, P. Speck, R. Van Moer, M. Vienne, J. KAUST Supcrcomputing Laboratory 4700 King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia Arvutitcaduse Instituut Tartu Ülikool Liivi 2 Tartu50409 Estonia Stochastic Numerics Group 4700 King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia Electrical and Computer Engineering University of Michigan Ann ArborMI48109-2122 United States Numerical Algorithms Group Wilkinson House Jordan Hill Road Oxford0X2 8DR United Kingdom Numerical Mathematics Group 4700 King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia Department of Mathematical Sciences University of Bath BathBA2 7 AY United Kingdom CAEN Advanced Computing University of Michigan Ann ArborMI48109-2094 United States Lnstitut für Analysis und Scientific Computing Technische Universität Wien Wiedner Haupstrasse 8-10 Wien1040 Austria Compulcr Sciences Department BSC UPC c/Jordi Girona Barcelona Calalunya08034 Spain Biomedical Engineering University of Michigan Ann ArborMI48109-2122 United States Jülich Supercomputing Centre Forschungszentrum Jülich GmbH Germany Germany National Center for Supercomputing Applications University of Illinois at Urbiina-Chanipaign UrbanaIL61801 United States Texas Advanced Computing Center University of Texas at Austin AustinTX78758-4497 United States

ISBN: (纸本)9781510810600

The cubic Klein-Gordon equation is a simple but non-trivial partial differential equation whose numerical solution has the main building blocks required for the solution of many other partial differential equations. In this study, the library 2DE-COMP&FFT is used in a Fourier spectral scheme to solve the Klein-Gordon equation and strong scaling of the code is examined on thirteen different machines for a problem size of 5123. The results are useful in assessing likely performance of other parallel fast Fourier transform based programs for solving partial differential equations. The problem is chosen to be large enough to solve on a workstation, yet also of interest to solve quickly on a supercomputer, in particular for parametric studies. Unlike the Linpack benchmark, a high ranking will not be obtained by simply building a bigger computer. © 2015 Aseeri et al.

关键词： Fast Fourier transforms

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High Statistics Measurements of Pedestrian Dynamics

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Transportation Research Procedia 2014年 2卷 96-104页

作者： Alessandro Corbetta Luca Bruno Adrian Muntean Federico Toschi CASA- Centre for Analysis Scientific computing and Applications Department of Mathematics and Computer Science Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands Department of Structural Geotechnical and Building Engineering Politecnico di Torino Corso Duca degli Abruzzi 24 10126 Torino Italy Department of Architecture and Design Politecnico di Torino Viale Mattioli 39 10125 Torino Italy ICMS - Institute for Complex Molecular Systems Eindhoven University of Technology The Netherlands Department of Applied Physics Eindhoven University of Technology 5600 MB Eindhoven The Netherlands CNR-IAC Via dei Taurini 19 00185 Rome Italy

Aiming at a quantitative understanding of basic aspects of pedestrian dynamics, extensive and high-accuracy measurements of real-life pedestrian trajectories have been performed. A measurement strategy based on Microsoft Kinect TM has been used. Specifically, more than 100.000 pedestrians have been tracked while walking along a trafficked corridor at the Eindhoven University of Technology, The Netherlands. The obtained trajectories have been analyzed as ensemble data. The main result consists of a statistical descriptions of pedestrian characteristic kinematic quantities such as positions and fundamental diagrams, possibly conditioned to the local crowd flow (e.g. co-flow or counter-flow).

关键词： pedestrian dynamics pedestrian tracking high statistics measurements statistical mechanics

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