• 제목/요약/키워드: parallel algorithms

검색결과 653건 처리시간 0.026초

전 분류 기법과 후 분류 기법의 조합을 통한 효율적 병렬 타일 가시화 알고리듬 개발 (Development of Efficient Parallel Tiled Display Algorithms by Combining the Sort-first and the Sort-last Sorting Methods)

  • 최윤혁;김일호;김홍성;조진연
    • 한국항공우주학회지
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    • 제36권2호
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    • pp.146-155
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    • 2008
  • 본 논문에서는 고해상도 타일 가시화 시스템의 성능 향상을 위해 전 분류 기법과 후 분류 기법을 조합하여 두 가지 병렬-타일 가시화 알고리듬을 제안하였다. 전 분류에서는 디스플레이 리스트와 시각 절두체 선별 기법을 이용하였으며, 후 분류에서는 선 탐색 부분 후 분류기법을 이용하였다. 벤치마킹 테스트를 통해 제안된 두 병렬-타일 가시화 기법의 성능을 고찰하였으며, 이 결과를 기반으로 제안된 두 가지 병렬-타일 가시화 알고리듬 중에서 주어진 가시화 모델에 대해 더 효율적인 알고리듬을 선정하는 방안을 제시하였다.

충돌해석을 위한 병렬유한요소 알고리즘 (A Parallel Finite Element Procedure for Contact-Impact Problems)

  • 하재선
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 추계학술대회
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    • pp.1286-1290
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    • 2003
  • This paper presents a newly implemented parallel finite element procedure for contact-impact problems. Three sub-algorithms are includes in the proposed parallel contact-impact procedure, such as a parallel Belytschko-Lin-Tsay (BLT) shell element generation, a parallel explicit time integration scheme, and a parallel contact search algorithm based on the master slave slide-line algorithm. The underlying focus of the algorithms is on its effectiveness and efficiency for inclusion in future finite element systems on parallel computers. Throughout this research, a prototype code, named GT-PARADYN, is developed on the IBM SP2, a distributed-memory computer. Some numerical examples are provided to demonstrate the timing results of the procedure, discussing the accuracy and efficiency of the code.

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Heuristic Algorithms for Parallel Machine Scheduling Problems with Dividable Jobs

  • Tsai, Chi-Yang;Chen, You-Ren
    • Industrial Engineering and Management Systems
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    • 제10권1호
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    • pp.15-23
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    • 2011
  • This research considers scheduling problems with jobs which can be divided into sub-jobs and do not required to be processed immediately following one another. Heuristic algorithms considering how to divide jobs are proposed in an attempt to find near-optimal solutions within reasonable run time. The algorithms contain two phases which are executed recursively. Phase 1 of the algorithm determines how jobs should be divided while phase 2 solves the scheduling problem given the sub-jobs established in phase 1. Simulated annealing and genetic algorithms are applied for the two phases and four heuristic algorithms are established. Numerical experiment is conducted to determine the best parameter values for the heuristic algorithms. Examples with different sizes and levels of complexity are generated. Performance of the proposed algorithms is evaluated. It is shown that the proposed algorithms are able to efficiently and effectively solve the considered problems.

AN OPTIMAL PARALLEL ALGORITHM FOR SOLVING ALL-PAIRS SHORTEST PATHS PROBLEM ON CIRCULAR-ARC GRAPHS

  • SAHA ANITA;PAL MADHUMANGAL;PAL TAPAN K.
    • Journal of applied mathematics & informatics
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    • 제17권1_2_3호
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    • pp.1-23
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    • 2005
  • The shortest-paths problem is a fundamental problem in graph theory and finds diverse applications in various fields. This is why shortest path algorithms have been designed more thoroughly than any other algorithm in graph theory. A large number of optimization problems are mathematically equivalent to the problem of finding shortest paths in a graph. The shortest-path between a pair of vertices is defined as the path with shortest length between the pair of vertices. The shortest path from one vertex to another often gives the best way to route a message between the vertices. This paper presents an $O(n^2)$ time sequential algorithm and an $O(n^2/p+logn)$ time parallel algorithm on EREW PRAM model for solving all pairs shortest paths problem on circular-arc graphs, where p and n represent respectively the number of processors and the number of vertices of the circular-arc graph.

竝列處理機械상에서 總作業完了時間의 最小化解法에 관한 硏究 (A Study on Approximate and Exact Algorithms to Minimize Makespan on Parallel Processors)

  • 안상형;이송근
    • 한국경영과학회지
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    • 제16권2호
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    • pp.14-35
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    • 1991
  • The purpose of this study is to develop an efficient exact algorithm for the problem of scheduling n in dependent jobs on m unequal parallel processors to minimize makespan. Efficient solutions are already known for the preemptive case. But for the non-preemptive case, this problem belongs to a set of strong NP-complete problems. Hence, it is unlikely that the polynomial time algorithm can be found. This is the reason why most investigations have bben directed toward the fast approximate algorithms and the worst-case analysis of algorithms. Recently, great advances have been made in mathematical theories regarding Lagrangean relaxation and the subgradient optimization procedure which updates the Lagrangean multipliers. By combining and the subgradient optimization procedure which updates the Lagrangean multipliers. By combining these mathematical tools with branch-and-bound procedures, these have been some successes in constructing pseudo-polynomial time algorithms for solving previously unsolved NP-complete problems. This study applied similar methodologies to the unequal parallel processor problem to find the efficient exact algorithm.

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병렬처리리례 상에서 동작업완료시간의 최소화해법에 관한 연구 (A Study on Approximate and Exact Algorithms to Minimize Makespan on Parallel Processors)

  • 안상형;이송근
    • 한국경영과학회지
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    • 제16권2호
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    • pp.13-35
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    • 1991
  • The purpose of this study is to develop an efficient exact algorithm for the problem of scheduling n in dependent jobs on m unequal parallel processors to minimize makespan. Efficient solutions are already known for the preemptive case. But for the non-preemptive case, this problem belongs to a set of strong NP-complete problems. Hence, it is unlikely that the polynomial time algorithm can be found. This is the reason why most investigations have bben directed toward the fast approximate algorithms and the worst-case analysis of algorithms. Recently, great advances have been made in mathematical theories regarding Lagrangean relaxation and the subgradient optimization procedure which updates the Lagrangean multipliers. By combining and the subgradient optimization procedure which updates the Lagrangean multipliers. By combining these mathematical tools with branch-and-bound procedures, these have been some successes in constructing pseudo-polynomial time algorithms for solving previously unsolved NP-complete problems. This study applied similar methodologies to the unequal parallel processor problem to find the efficient exact algorithm.

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CONVERGENCE OF PARALLEL ITERATIVE ALGORITHMS FOR A SYSTEM OF NONLINEAR VARIATIONAL INEQUALITIES IN BANACH SPACES

  • JEONG, JAE UG
    • Journal of applied mathematics & informatics
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    • 제34권1_2호
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    • pp.61-73
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    • 2016
  • In this paper, we consider the problems of convergence of parallel iterative algorithms for a system of nonlinear variational inequalities and nonexpansive mappings. Strong convergence theorems are established in the frame work of real Banach spaces.

멀티프로세서 태스크 할당을 위한 GA과 SA의 비교 (Comparison of Genetic Algorithms and Simulated Annealing for Multiprocessor Task Allocation)

  • 박경모
    • 한국정보처리학회논문지
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    • 제6권9호
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    • pp.2311-2319
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    • 1999
  • 병렬 컴퓨팅에 있어 NP-complete 문제인 태스크 할당문제에 대한 두 가지 휴리스틱 알고리즘을 제시한다. 할당문제는 분산 메모리 멀티컴퓨터의 멀티 프로세싱 노드에 다중통신 태스크들을 최적의 매핑을 찾는 것이다. 태스크들을 목표 시스템 구조의 노드들에 매핑시키는 목적은 해법 품질에 손상 없이 병렬 실행시간을 최소화하기 위함이다. 많은 휴리스틱 기법들이 만족한 매핑을 얻기 위해 채택되어 왔다. 본 논문에서 제시되는 휴리스틱 기법은 유전자 알고리즘(GA)과 시뮬레이티드 어닐링(SA) 기법에 기반을 둔다. 매핑 설정을 위한 총 계산 비용으로 목적함수를 수식화하고 휴리스틱 알고리즘들의 성능을 평가한다. 랜덤, 그리디, 유전자, 어닐링 알고리즘들을 사용하여 얻은 해법의 품질과 시간을 비교한다. 할당 알고리즘 시뮬레이션 연구를 통한 실험적 결과를 보여준다.

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A Study on Sorting in A Computer Using The Binary Multi-level Multi-access Protocol

  • Jung Chang-Duk
    • 한국지능정보시스템학회:학술대회논문집
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    • 한국지능정보시스템학회 2006년도 춘계학술대회
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    • pp.303-310
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    • 2006
  • The sorting algorithms have been developed to take advantage of distributed computers. But the speedup of parallel sorting algorithms decrease rapidly with increased number of processors due to parallel processing overhead such as context switching time and inter-processor communication cost. In this paper, we propose a parallel sorting method which provides linear speedup of an optimal serial algorithm for a system with a large number of processors. This algorithm may even provide superlinear speedup for a practical system. The algorithm takes advantage of an interconnection network properties and its protocol.

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AN EFFICIENT PRAM ALGORITHM FOR MAXIMUM-WEIGHT INDEPENDENT SET ON PERMUTATION GRAPHS

  • SAHA ANITA;PAL MADHUMANGAL;PAL TAPAN K.
    • Journal of applied mathematics & informatics
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    • 제19권1_2호
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    • pp.77-92
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    • 2005
  • An efficient parallel algorithm is presented to find a maximum weight independent set of a permutation graph which takes O(log n) time using O($n^2$/ log n) processors on an EREW PRAM, provided the graph has at most O(n) maximal independent sets. The best known parallel algorithm takes O($log^2n$) time and O($n^3/log\;n$) processors on a CREW PRAM.