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Multi-scale predictability of high-impact stratospheric clear air turbulence events for air force platforms

Multi-scale predictability of high-impact stratospheric clea...

Department of Defense - hpcmp users group conference 2007;high performance computing modernization program: A Bridge to Future Defense, dod hpcmp ugc

作者： Mahalov, Alex Moustaoui, Mohamed Nichols, Basil Program in Environmental Fluid Dynamics Department of Mechanical and Aerospace Engineering Arizona State University Tempe AZ United States

ISBN: (纸本)0769530885

Vertical nesting and adaptive vertical gridding in nested mesoscale Weather Research and Forecasting (WRF)/microscale codes are developed. The inner nest of WRF is coupled with a sequence of embedded microscale nests, both horizontally and vertically. The fully three-dimensional (3D), compressible Navier-Stokes equations are solved with a stretched, adaptive grid in the vertical, with grid spacing down to a few meters in thin Clear Air Turbulence (CAT) layers where strong turbulent mixing occurs. For nesting, both lateral and vertical boundary conditions are treated via relaxation zones where the velocity and temperature fields are relaxed to those obtained from the WRF inner nest. This methodology is applied to the analysis of field data from T-REX campaign of measurements. Real case simulations based on initial and boundary conditions from high resolution T799 L91 European Centre for Medium-Range Weather Forecasts (ECMWF) analysis data are conducted. The embedded microscale nests predict localized shear layers and diagnose stiff gradients of vertical velocity and potential temperature above the tropopause and in the lower stratosphere. Three-dimensional instability mechanisms and turbulent dynamics within these CAT layers are fully resolved. © 2007 IEEE.

关键词： Boundary conditions

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Spatial processing of urban acoustic wave fields from high-performance computations

Spatial processing of urban acoustic wave fields from high-p...

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Department of Defense - hpcmp users group conference 2007;high performance computing modernization program: A Bridge to Future Defense, dod hpcmp ugc

作者： Ketcham, Stephen A. Wilson, D. Keith Cudney, Harley H. Parker, Michael W. Hanover NH United States

ISBN: (纸本)0769530885

Future US Army ground sensors in urban terrain will process acoustic signals to detect, classify, and locate sources of interest. Optimal processing will require understanding of the effects of the urban infrastructure on sound propagation. These include multi-path phenomena that will complicate sensing, and must be accounted for in sensor placement and performance algorithms. The objective of this work is to develop spatial processing techniques for acoustic wave propagation data from three-dimensional high-performance computations to quantify scattering due to urban structures and develop reduced-order models of wave-field data. The work applies Fourier analysis to urban acoustic wave-field data to generate measures of signal fading caused by scattering. The work calculates these measures from ratios of Fourier transforms of wave-field signals with and without scattering to isolate the structure-induced scattering. In addition, we calculate impulse response functions of acoustic wave-field data, and use these functions as the input to a system realization algorithm to produce reduced-order wave-field models. The results include signal fading as functions of distance and frequency for an urban acoustic model that includes structures like those in a small-city periphery. The results also include predicted acoustic wave-field signals from reduced-order models in comparison with full-model signals. We conclude that the spatial processing of urban acoustic wave fields from high-performance computations produces broadly useful measures for understanding and modeling urban wave propagation. © 2007 IEEE.

关键词： Three dimensional computer graphics

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Computations of a maneuvering unmanned combat air vehicle using a high-order overset-grid method

Computations of a maneuvering unmanned combat air vehicle us...

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Department of Defense - hpcmp users group conference 2007;high performance computing modernization program: A Bridge to Future Defense, dod hpcmp ugc

作者： Gordnier, Raymond E. Sherer, Scott E. Visbal, Miguel R. Dayton OH United States

ISBN: (纸本)0769530885

Simulating the flow around a maneuvering unmanned combat air vehicle (UCAV) requires a computational method capable of modeling such complex flow features as massive separation, transition from laminar to turbulent flow, and nonlinear vortex dynamics. In the present paper, a parallel, high-order, overset-grid solver is used to compute these challenging flowfields. Turbulence modeling is accomplished using an implicit Large Eddy Simulation (LES) approach, which exploits the characteristics of the sixth-order accurate computational scheme coupled with high-order, low pass filtering. This scheme provides a unified computational approach for the laminar/transitional/turbulent flowfields encountered by maneuvering UCAVs. A general oversetgrid capability, including high-order interpolation and the ability to handle holes while maintaining high-order accuracy, has been incorporated into the flow solver. This high-order method is applied to the simulation of a canonical low sweep delta wing and a generic, tailless, low-sweep wing UCAV configuration. Computations performed for the low sweep delta wing at moderate Reynolds numbers demonstrate the ability of the implicit large-eddy simulation (ILES) approach to capture important Reynolds number effects for these complicated transitional flowfields. Groundbreaking high-order computations for the generic UCAV configuration are then presented with the fundamental aerodynamic phenomena of the configuration being examined using the improved accuracy of the high-order overset method. Comparisons with available experimental measurements are made to demonstrate the ability of this high-fidelity modeling approach to capture the complex flow physics involved. © 2007 IEEE.

关键词： Reynolds number

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Parallel 3D FDTD simulator for photonic crystals

Parallel 3D FDTD simulator for photonic crystals

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Department of Defense - hpcmp users group conference 2007;high performance computing modernization program: A Bridge to Future Defense, dod hpcmp ugc

作者： Ayubi-Moak, Jason S. Goodnick, Stephen M. Speyer, Gil Stanzione, Daniel C. Sotirelis, Paul Arizona State University Tempe AZ United States High Performance Technologies Inc. Wright-Patterson AFB Dayton OH United States

ISBN: (纸本)0769530885

Photonic crystals have shown a great deal of promise for the realization of true integrated optics. Waveguides with small bends may be formed allowing compact integrated photonic circuits to be formed. Full three-dimensional (3D) photonic simulations are required in order to realize very low loss, integrated photonic crystal circuits. Needless to say, the design and fabrication of such fully 3D structures is challenging, and thus efficient simulation tools are necessary to identify the optimum structures for different applications. Researchers at the Department of Defense (dod) and Arizona State University (ASU) have independently developed parallel Finite Difference Time Domain (FDTD) codes, with the goal of scaling up each simulator for complicated structures such as 3D optical integrated circuits (OIC). As the name implies, FDTD is a popular time-domain method for solving Maxwell's equations for the electric and magnetic fields. These two curl equations are solved explicitly in time over half-step intervals, where the values of one set of field values (e.g., electric fields) are used at the successive interval to solve for the other field (e.g., magnetic field) in a time marching fashion. The goal of our current work is to realize a fully parallel FDTD code scalable to 108 FDTD grid points in order to have sufficient resolution to model even a relatively limited number of periods of a given waveguide structure. This requires both a scalable parallel FDTD code, as well as one with the proper boundary conditions and more efficient algorithms to reduce run. The work and results discussed herein address both the scalability and the efficiency of the time-domain algorithm. © 2007 IEEE.

关键词： Finite difference time domain method

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Department of Defense - Proceedings of the hpcmp users group conference 2007;high performance computing modernization program: A Bridge to FuTu. Preface

Department of Defense - Proceedings of the HPCMP Users Group...

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Department of Defense - Proceedings of the hpcmp users group conference 2007;high performance computing modernization program: A Bridge to Future Defense, dod hpcmp ugc 2007年 x-xi页

作者： Post, Douglass E. DoD HPCMP

No abstract available

ISBN: (纸本)0769530885

No abstract available

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Targeting CCM-, CEA-, and CSM-Based computing to specific architectures based upon hpcmp systems assessment

Targeting CCM-, CEA-, and CSM-Based computing to specific ar...

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conference on high performance Computer modernization program

作者： Bennett, Paul M. Cable, Sam B. Mahmoodi, Mahin Oppe, Thomas C. USACE Engn Res & Dev Ctr Computat Sci & Engn Grp Wichita KS 67260 USA

ISBN: (纸本)9780769527970

Each year the Department of Defense high performance computing modernization program (HPCAV) acquires new supercomputing hardware through a rigorous acquisition process, denoted "TI" for technology insertion, based primarily on application benchmarking. The corresponding suite of applications spans many disciplines and is carefully constructed to ensure that the hpcmp workload is accurately reflected. For the most recent acquisition cycle (TI-06), GAMESS, LAMMPS, OOCORE, and CTH7 were used to represent the computational chemistry and materials (CCM, computational electromagnetics and acoustics (CEA), and computational structural mechanics (CSM) computational technology areas (CTAs) in the workload, respectively. This paper will compare the performance of these four codes representing the CCM, CEA, and CSM components, respectively, of the TI-06 benchmarking suite on hpcmp systems to determine which system is best suited for each CTA.

关键词： Benchmarking

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Optimization of LAMMPS

Optimization of LAMMPS

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conference on high performance Computer modernization program

作者： Fischer, James Natoli, Vincent Richie, David High Performance Technol Inc Aberdeen Proving Ground MD 70470 USA Stone Ridge Technol Los Angeles CA USA

ISBN: (纸本)9780769527970

The Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code is part of the Department of Defense high performance computing modernization program (hpcmp) Technology Insertion (TI) benchmarking suite of applications. As a component of the TI benchmarking applications, LAMMPS is a significant contributor to Computational Chemistry and Materials Science requirements within the dod. Ensuring its optimal performance on hpcmp resources is a high priority. The CCM-KY5-003 User Productivity Enhancements and Technology Transfer (PET) project was created to profile and optimize LAMMPS to improve its performance and efficiency on two hpcmp assets, Eagle (Altix 3700) and JVN (Linux Cluster). Profiling efforts were completed on Eagle using the Tuning and Analysis Utilities (TAU) application in conjunction with the performance Application programming Interface (PAPI). The time and hardware counter data was analyzed with ParaProf and PerfExplorer, while the trace data was automatically analyzed by the Kit for Objective Judgment and Knowledge-based Detection of performance Bottlenecks (KOJAK). The profiling effort used three different model systems, where each uses a different physical potential. Several opportunities for performance improvement were identified in the critical portions of the code, such as loop-static branching conditions, multi-dimensional C-arrays and redundant integer, and floating-point operations. In addition to algorithmic changes, compiler options and machine-specific instructions were also investigated. The performance of the code increased from 1.3x to 3.5x on Eagle and 1.2x to 1.8x on JVN depending on the physical potential employed.

关键词： Benchmarking

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Octave and python: high-level scripting languages productivity and performance evaluation

Octave and python: High-level scripting languages productivi...

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conference on high performance Computer modernization program

作者： Chaves, Juan Carlos Nehrbass, John Guilfoos, Brian Gardiner, Judy Ahalt, Stanley Krishnarnurthy, Ashok Unpingco, Jose Chalker, Alan Warnock, Andy Samsi, Siddharth Ohio Supercomp Ctr Columbus OH USA

ISBN: (纸本)9780769527970

Octave and Python are open source alternatives to MATLAB, which is widely used by the high performance computing modernization program (hpcmp) community. These languages are two well known examples of high-level scripting languages that promise to increase productivity without compromising performance on HPC systems. In this paper, we report our work and experience with these two non-traditional programming languages at the hpcmp Centers. We used a representative sample of SIP codes for the study, with special emphasis given to the understanding of issues such as portability, degree of complexity, productivity and suitability of Octave and Python to address Signal/image Processing (SIP) problems on the hpcmp HPC platforms. We implemented a relatively simple two-dimensional (2-D) FFT and a more complex image enhancement algorithm in Octave and Python and benchmarked these SIP codes on several hpcmp platforms, paying special attention to usability, productivity and performance aspects. Moreover, we performed a thorough benchmark containing important low level SIP core functions and algorithms and compared the outcome with the corresponding results for MATLAB. We found that the capabilities of these languages are comparable to MATLAB and they are powerful enough to efficiently implement complex SIP algorithms. Productivity and performance results for each language vary depending on the specific task and the availability of high level functions in each system to address such tasks. Therefore, the choice of the best language to use in a particular instance will strongly depend upon the specifics of the SIP application that needs to be addressed. We concluded that Octave and Python look like promising tools that may provide an alternative to MATLAB without compromising performance and productivity. Their syntax and functionality are similar enough to MATLAB to present a very shallow learning curve for experienced MATLAB users.

关键词： MATLAB

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ezHPC Security Architecture

ezHPC Security Architecture

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users group conference

作者： George Moncrief Trent Townsend Scotty Swillie Major Shared Resource Center (ERDC MSRC) USACE Engineer Research and Development Center Vicksburg MS USA

high performance computing (HPC) within the Department of Defense (dod) is vital to the execution of the research and development mission. However, users must access these resources using interfaces that are complicated, specialized, primitive, and opaque. ezHPC was developed to address this complexity. The ezHPC project is interesting in that it abstracts for the user many of the technical details and tools related to HPC within the dod high performance computing modernization program (hpcmp) while providing a Web-based application that allows user access to HPC resources. Leveraging open-source, widely available technology, the ezHPC security model addresses the dod security requirements for authentication, confidentiality, availability, and integrity. This paper discusses an architecture that employs end-to-end encryption, open-source technologies, message authentication codes, and authentication of users via the HP CMP-modified implementation of the Massachusetts Institute of Technology Kerberos. This architecture provides ezHPC the flexibility to reduce the technology barrier to those unfamiliar with interactive use of HPC systems while providing significant capability to more advanced users. The subsequent abstraction of HPC resources constitutes a security model for any Web-enabled application programming interface

关键词： Security Web server high performance computing User interfaces Research and development Computer architecture Abstracts Authentication Computer interfaces Military computing

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Optimization of LAMMPS

Optimization of LAMMPS

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users group conference

作者： James Fischer Vincent Natoli David Richie High Performance Technologies Inc. MD USA Stone Ridge Technology Bel Air MD USA

The Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code is part of the Department of Defense high performance computing modernization program (hpcmp) technology insertion (TI) benchmarking suite of applications. As a component of the TI benchmarking applications, LAMMPS is a significant contributor to Computational Chemistry and Materials Science requirements within the dod. Ensuring its optimal performance on hpcmp resources is a high priority. The CCM-KY5-003 User Productivity Enhancements and Technology Transfer (PET) project was created to profile and optimize LAMMPS to improve its performance and efficiency on two hpcmp assets, Eagle (Altix 3700) and JVN(Linux Cluster). Profiling efforts were completed on Eagle using the Tuning and Analysis Utilities (TAU) application in conjunction with the performance Application programming Interface (PAPI). The time and hardware counter data was analyzed with ParaProf and PerfExplorer, while the trace data was automatically analyzed by the Kit for Objective Judgment and Knowledge-based Detection of performance Bottlenecks (KOJAK). The profiling effort used three different model systems, where each uses a different physical potential. Several opportunities for performance improvement were identified in the critical portions of the code, such as loop-static branching conditions, multi-dimensional C-arrays and redundant integer, and floating-point operations. In addition to algorithmic changes, compiler options and machine-specific instructions were also investigated. The performance of the code increased from 1.3x to 3.5x on Eagle and 1.2x to 1.8x on JVN depending on the physical potential employed

关键词： performance analysis Data analysis Large-scale systems Computational modeling high performance computing Chemical technology Chemistry Materials science and technology Productivity Technology transfer

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