• 제목/요약/키워드: Parallel Computing

검색결과 266건 처리시간 0.115초

COMPUTATIONAL EFFICIENCY OF A MODIFIED SCATTERING KERNEL FOR FULL-COUPLED PHOTON-ELECTRON TRANSPORT PARALLEL COMPUTING WITH UNSTRUCTURED TETRAHEDRAL MESHES

  • Kim, Jong Woon;Hong, Ser Gi;Lee, Young-Ouk
    • Nuclear Engineering and Technology
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    • v.46 no.2
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    • pp.263-272
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    • 2014
  • Scattering source calculations using conventional spherical harmonic expansion may require lots of computation time to treat full-coupled three-dimensional photon-electron transport in a highly anisotropic scattering medium where their scattering cross sections should be expanded with very high order (e.g., $P_7$ or higher) Legendre expansions. In this paper, we introduce a modified scattering kernel approach to avoid the unnecessarily repeated calculations involved with the scattering source calculation, and used it with parallel computing to effectively reduce the computation time. Its computational efficiency was tested for three-dimensional full-coupled photon-electron transport problems using our computer program which solves the multi-group discrete ordinates transport equation by using the discontinuous finite element method with unstructured tetrahedral meshes for complicated geometrical problems. The numerical tests show that we can improve speed up to 17~42 times for the elapsed time per iteration using the modified scattering kernel, not only in the single CPU calculation but also in the parallel computing with several CPUs.

다분야통합최적설계 방법론의 병렬처리 성능 분석 (Performances of Multidisciplinary Design Optimization Methodologies in Parallel Computing Environment)

  • 안문열;이세정
    • 대한기계학회논문집A
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    • v.31 no.12
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    • pp.1150-1156
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    • 2007
  • Multidisciplinary design optimization methodologies play an essential role in modern engineering design which involves many inter-related disciplines. These methodologies usually require very long computing time and design tasks are hard to finish within a specified design cycle time. Parallel processing can be effectively utilized to reduce the computing time. The research on the parallel computing performance of MDO methodologies has been just begun and developing. This study investigates performances of MDF, IDF, SAND and CO among MDO methodologies in view of parallel computing. Finally, the best out of four methodologies is suggested for parallel processing purpose.

Design and optimization of steel trusses using genetic algorithms, parallel computing, and human-computer interaction

  • Agarwal, Pranab;Raich, Anne M.
    • Structural Engineering and Mechanics
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    • v.23 no.4
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    • pp.325-337
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    • 2006
  • A hybrid structural design and optimization methodology that combines the strengths of genetic algorithms, local search techniques, and parallel computing is developed to evolve optimal truss systems in this research effort. The primary objective that is met in evolving near-optimal or optimal structural systems using this approach is the capability of satisfying user-defined design criteria while minimizing the computational time required. The application of genetic algorithms to the design and optimization of truss systems supports conceptual design by facilitating the exploration of new design alternatives. In addition, final shape optimization of the evolved designs is supported through the refinement of member sizes using local search techniques for further improvement. The use of the hybrid approach, therefore, enhances the overall process of structural design. Parallel computing is implemented to reduce the total computation time required to obtain near-optimal designs. The support of human-computer interaction during layout optimization and local optimization is also discussed since it assists in evolving optimal truss systems that better satisfy a user's design requirements and design preferences.

Parallel Computing on Intensity Offset Tracking Using Synthetic Aperture Radar for Retrieval of Glacier Velocity

  • Hong, Sang-Hoon
    • 대한원격탐사학회지
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    • v.35 no.1
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    • pp.29-37
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    • 2019
  • Synthetic Aperture Radar (SAR) observations are powerful tools to monitor surface's displacement very accurately, induced by earthquake, volcano, ground subsidence, glacier movement, etc. Especially, radar interferometry (InSAR) which utilizes phase information related to distance from sensor to target, can generate displacement map in line-of-sight direction with accuracy of a few cm or mm. Due to decorrelation effect, however, degradation of coherence in the InSAR application often prohibit from construction of differential interferogram. Offset tracking method is an alternative approach to make a two-dimensional displacement map using intensity information instead of the phase. However, there is limitation in that the offset tracking requires very intensive computation power and time. In this paper, efficiency of parallel computing has been investigated using high performance computer for estimation of glacier velocity. Two TanDEM-X SAR observations which were acquired on September 15, 2013 and September 26, 2013 over the Narsap Sermia in Southwestern Greenland were collected. Atotal of 56 of 2.4 GHz Intel Xeon processors(28 physical processors with hyperthreading) by operating with linux environment were utilized. The Gamma software was used for application of offset tracking by adjustment of the number of processors for the OpenMP parallel computing. The processing times of the offset tracking at the 256 by 256 pixels of window patch size at single and 56 cores are; 26,344 sec and 2,055 sec, respectively. It is impressive that the processing time could be reduced significantly about thirteen times (12.81) at the 56 cores usage. However, the parallel computing using all the processors prevent other background operations or functions. Except the offset tracking processing, optimum number of processors need to be evaluated for computing efficiency.

Windows 운영체제 기반의 병렬 계산 환경 (Parallel Computing Environment based on Windows Operating System)

  • 최정열;신재렬;김명호
    • 한국항공우주학회지
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    • v.31 no.4
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    • pp.16-25
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    • 2003
  • Windows 운영체제 기반의 병렬처리 환경을 구축하였으며, 리눅스 운영체제 기반의 시스템과 비교하여 병렬처리 성능을 살펴보았다. Windows 클러스터는 Fast-Ethernet으로 연결된 서버와 클라이언트로 구성되어 있으며, 두 개의 클러스터가 동시에 또는 개별적으로 운용될 수 있도록 구성하였다. 계산 도구로서 Compaq Visual Fortran 컴파일러와 두 개의 MPI 라이브러리, MPICH.NT.1.2.2 와 MP-MPICHNT.1.2 를 설치하였다. 병렬 처리 성능 시험은 이차원 예조건화 Navier-Stokes 코드를 이용하여 수행하였으며, 리눅스 클러스터의 결과와 비교하여, 프로세서의 수, 문제의 크기 그리고 MPI 라이브러리에 따른 의존성을 살펴보았다. 이 결과는 사용자에게 친숙한 Windows 운영체제 기반의 클러스터가 병렬 계산 환경에서도 유용하며, 이전의 리눅스 클러스터에 버금가는 우수한 성능을 보여주었다.

Fully Homomorphic Encryption Based On the Parallel Computing

  • Tan, Delin;Wang, Huajun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.1
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    • pp.497-522
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    • 2018
  • Fully homomorphic encryption(FHE) scheme may be the best method to solve the privacy leakage problem in the untrusted servers because of its ciphertext calculability. However, the existing FHE schemes are still not being put into the practical applications due to their low efficiency. Therefore, it is imperative to find a more efficient FHE scheme or to optimize the existing FHE schemes so that they can be put into the practical applications. In this paper, we optimize GSW scheme by using the parallel computing, and finally we get a high-performance FHE scheme, namely PGSW scheme. Experimental results show that the time overhead of the homomorphic operations in new FHE scheme will be reduced manyfold with the increasing of processing units number. Therefore, our scheme can greatly reduce the running time of homomorphic operations and improve the performance of FHE scheme through sacrificing hardware resources. It can be seen that our FHE scheme can catalyze the development of FHE.

An Efficient Multidimensional Index Structure for Parallel Environments

  • Bok Koung-Soo;Song Seok-Il;Yoo Jae-Soo
    • International Journal of Contents
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    • v.1 no.1
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    • pp.50-58
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    • 2005
  • Generally, multidimensional data such as image and spatial data require large amount of storage space. There is a limit to store and manage those large amounts of data in single workstation. If we manage the data on parallel computing environment which is being actively researched these days, we can get highly improved performance. In this paper, we propose a parallel multidimensional index structure that exploits the parallelism of the parallel computing environment. The proposed index structure is nP(processor)-nxmD(disk) architecture which is the hybrid type of nP-nD and 1P-nD. Its node structure in-creases fan-out and reduces the height of an index. Also, a range search algorithm that maximizes I/O parallelism is devised, and it is applied to k-nearest neighbor queries. Through various experiments, it is shown that the proposed method outperforms other parallel index structures.

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PDP 시스템의 실시간 모니터링 및 시각화 (Realtime Monitoring and Visualization for PDP System)

  • 김수자;송은하;박복자;정영식
    • 한국멀티미디어학회논문지
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    • v.7 no.5
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    • pp.755-765
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    • 2004
  • 최근에 많은 유휴 상태의 호스트 자원들을 이용한 인터넷 기반 분산/병렬 컴퓨팅은 대용량 작업처리와 여러 중요 논제들에 대해 그 유용성이 증명되고 있다. 대용량 작업이 수행되는 동안, 작업에 참여하는 호스트의 성능과 상태 변화에 대처하기 위한 실시간 모니터링 기능이 요구된다. 본 연구에서는 글로벌 컴퓨팅 (global computing) 인트라스트럭처(infrastructure)로 구축된 인터넷 기반 분산/병렬 처리 프레임워크인 PDP(Parallel Distributed Processing)상의 실시간 모니터링 및 시각화에 대한 내용을 소개한다.

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Optimal Design of a Direct-Driven PM Wind Generator Aimed at Maximum AEP using Coupled FEA and Parallel Computing GA

  • Jung, Ho-Chang;Lee, Cheol-Gyun;Hahn, Sung-Chin;Jung, Sang-Yong
    • Journal of Electrical Engineering and Technology
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    • v.3 no.4
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    • pp.552-558
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    • 2008
  • Optimal design of the direct-driven Permanent Magnet(PM) wind generator, combined with F.E.A(Finite Element Analysis) and Genetic Algorithm(GA), has been performed to maximize the Annual Energy Production(AEP) over the entire wind speed characterized by the statistical model of wind speed distribution. Particularly, the proposed parallel computing via internet web service has contributed to reducing excessive computing times for optimization.