• Title/Summary/Keyword: parallel algorithms

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Embedding Binomial Trees in Complete Binary Trees (이항트리의 완전이진트리에 대한 임베딩)

  • 윤수만;최정임형석
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.479-482
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    • 1998
  • Whether a given tree is a subgraph of the interconnection network topology is one of the important problem in parallel computing. Trees are used as the underlying structure for divide and conquer algorithms and provide the solution spaces for NP-complete problems. Complete binary trees are the basic structure among those trees. Binomial trees play an important role in broadcasting messages in parallel networks. If binomial trees can be efficiently embedded in complex binary trees, broadcasting algorithms can be effeciently performed on the interconnection networks. In this paper, we present average dilation 2 embedding of binomial trees in complete binary trees.

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Deep Web and MapReduce

  • Tao, Yufei
    • Journal of Computing Science and Engineering
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    • v.7 no.3
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    • pp.147-158
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    • 2013
  • This invited paper introduces results on Web science and technology obtained during work with the Korea Advanced Institute of Science and Technology. In the first part, we discuss algorithms for exploring the deep Web, which refers to the collection of Web pages that cannot be reached by conventional Web crawlers. In the second part, we discuss sorting algorithms on the MapReduce system, which has become a dominant paradigm for massive parallel computing.

Application of Genetic Algorithms to a Job Scheduling Problem (작업 일정계획문제 해결을 위한 유전알고리듬의 응용)

  • ;;Lee, Chae Y.
    • Journal of the Korean Operations Research and Management Science Society
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    • v.17 no.3
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    • pp.1-12
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    • 1992
  • Parallel Genetic Algorithms (GAs) are developed to solve a single machine n-job scheduling problem which is to minimize the sum of absolute deviations of completion times from a common due date. (0, 1) binary scheme is employed to represent the n-job schedule. Two selection methods, best individual selection and simple selection are examined. The effect of crossover operator, due date adjustment mutation and due date adjustment reordering are discussed. The performance of the parallel genetic algorithm is illustrated with some example problems.

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A PARALLEL ITERATIVE METHOD FOR A FINITE FAMILY OF BREGMAN STRONGLY NONEXPANSIVE MAPPINGS IN REFLEXIVE BANACH SPACES

  • Kim, Jong Kyu;Tuyen, Truong Minh
    • Journal of the Korean Mathematical Society
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    • v.57 no.3
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    • pp.617-640
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    • 2020
  • In this paper, we introduce a parallel iterative method for finding a common fixed point of a finite family of Bregman strongly nonexpansive mappings in a real reflexive Banach space. Moreover, we give some applications of the main theorem for solving some related problems. Finally, some numerical examples are developed to illustrate the behavior of the new algorithms with respect to existing algorithms.

Realizing TDNN for Word Recognition on a Wavefront Toroidal Mesh-array Neurocomputer

  • Hong Jeong;Jeong, Cha-Gyun;Kim, Myung-Won
    • Journal of Electrical Engineering and information Science
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    • v.1 no.1
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    • pp.98-107
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    • 1996
  • In this paper, we propose a scheme that maps the time-delay neural network (TDNN) into the neurocomputer called EMIND-II which has the wavefront toroidal mesh-array structure. This neurocomputer is scalable, consists of many timeshared virtual neurons, is equipped with programmable on-chip learning, and is versatile for building many types of neural networks. Also we define the programming model of this array and derive the parallel algorithms about TDNN for the proposed neurocomputer EMIND-II. In addition, the computational complexities for the parallel and serial algorithms are compared. Finally, we introduce an application of this neurocomputer to word recognition.

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Parallel Algorithms for Finding δ-approximate Periods and γ-approximate Periods of Strings over Integer Alphabets (정수문자열의 δ-근사주기와 γ-근사주기를 찾는 병렬알고리즘)

  • Kim, Youngho;Sim, Jeong Seop
    • Journal of KIISE
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    • v.44 no.8
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    • pp.760-766
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    • 2017
  • Repetitive strings have been studied in diverse fields such as data compression, bioinformatics and so on. Recently, two problems of approximate periods of strings over integer alphabets were introduced, finding minimum ${\delta}-approximate$ periods and finding minimum ${\gamma}-approximate$ periods. Both problems can be solved in $O(n^2)$ time when n is the length of the string. In this paper, we present two parallel algorithms for solving the above two problems in O(n) time using $O(n^2)$ threads, respectively. The experimental results show that our parallel algorithms for finding minimum ${\delta}-approximate$ (resp. ${\gamma}-approximate$) periods run approximately 19.7 (resp. 40.08) times faster than the sequential algorithms when n = 10,000.

Obtaining 1-pixel Width Line Using an Enhanced Parallel Thinning Algorithm (병렬 세선화 알고리즘을 이용한 1-화소 굵기의 선 구하기)

  • Kwon, Jun-Sik
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.1
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    • pp.1-6
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    • 2009
  • A Thinning algorithm is a very Important factor in order to recognize the character, figure, and drawing. Until comparatively lately, the thinning algorithm was proposed by various methods. In this paper, we ascertain the point at issue of ZS(Zhang and Suen), LW(Lu and Wang) and WHF(Wang, Hui and Fleming) algorithms that are the parallel thinning algorithms. The parallel thinning algorithm means the first processing doesn't have to influence to the second processing. ZS algorithm has a problem which loses pixels in slanting lines and LW algorithm doesn't have one pixel width in slanting lines. So I propose an advanced parallel thinning algorithm that connects the pixels each other and preserve the end point.

An Advanced Parallel Join Algorithm for Managing Data Skew on Hypercube Systems (하이퍼큐브 시스템에서 데이타 비대칭성을 고려한 향상된 병렬 결합 알고리즘)

  • 원영선;홍만표
    • Journal of KIISE:Computer Systems and Theory
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    • v.30 no.3_4
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    • pp.117-129
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    • 2003
  • In this paper, we propose advanced parallel join algorithm to efficiently process join operation on hypercube systems. This algorithm uses a broadcasting method in processing relation R which is compatible with hypercube structure. Hence, we can present optimized parallel join algorithm for that hypercube structure. The proposed algorithm has a complete solution of two essential problems - load balancing problem and data skew problem - in parallelization of join operation. In order to solve these problems, we made good use of the characteristics of clustering effect in the algorithm. As a result of this, performance is improved on the whole system than existing algorithms. Moreover. new algorithm has an advantage that can implement non-equijoin operation easily which is difficult to be implemented in hash based algorithm. Finally, according to the cost model analysis. this algorithm showed better performance than existing parallel join algorithms.

Task Creation and Assignment based on Object Caching for Parallel Spatial Join (병렬공간 조인을 위한 객체 캐쉬 기반 태스크 생성 및 할당)

  • 서영덕;김진덕;홍봉희
    • Journal of KIISE:Software and Applications
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    • v.26 no.10
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    • pp.1178-1178
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    • 1999
  • A spatial join has the property that its execution time exponentially increases in proportion to the number of spatial objects. Recently, there have been many attempts for improving the performance of the spatial join by using parallel processing schemes, In the case of executing parallel spatial join using the parallel machine with shared disk architecture, the disk bottleneck of parallel processing of spatial join worsens in comparison with sequential spatial join. This paper presents the algorithms of task creation and assignment to reduce the disk bottleneck caused by accessing the shared disk at the same time, and to minimize message passing between processors, This paper proposes object caching which is a higher level of abstraction than page caching, and uses it to do creation and assignment of tasks according to temporal and spatial localities for minimizing disk access time. The object caching shows the performance improvement of 50%. The task creation and assignment using localities gives the gain of 30% and 20%. Overall performance evaluation of the proposed algorithms shows 7.2 times speed up than those of sequential execution of spatial joins.

Applying Distributed Agents to Parallel Genetic Algorithm on Dynamic Network Environments (동적 네트워크 환경하의 분산 에이전트를 활용한 병렬 유전자 알고리즘 기법)

  • Baek Jin-Wook;Bang Jeon-Won
    • Journal of the Korea Society of Computer and Information
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    • v.11 no.4 s.42
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    • pp.119-125
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    • 2006
  • Distributed Systems can be defined as set of computing resources connected by computer network. One of the most significant techniques in optimization problem domains is parallel genetic algorithms, which are based on distributed systems. Since the status of dynamic network environments such as Internet and mobile computing. can be changed continually, it must not be efficient on the dynamic environments to solve an optimization problem using previous parallel genetic algorithms themselves. In this paper, we propose the effective technique, in which the parallel genetic algorithm can be used efficiently on the dynamic network environments.

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