• Title/Summary/Keyword: 병렬컴퓨팅

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Performance Evaluation of Real-Time Transaction Processing in a Shared Disk Cluster (공유 디스크 클러스터에서 실시간 트랜잭션 처리의 성능 평가)

  • Lee Sangho;Ohn Kyungoh;Cho Haengrae
    • Journal of KIISE:Databases
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    • v.32 no.2
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    • pp.142-150
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    • 2005
  • A shared disks (SD) cluster couples multiple computing nodes, and every node shares a common database at the disk level. A great deal of research indicates that the SD cluster is suitable to high performance transaction processing, but the aggregation of SD cluster with real-time processing has not been investigated at all. A real-time transaction has not only ACID properties of traditional transactions but also time constraints. By adopting cluster technology, the real-time services will be highly available and can exploit inter-node parallelism. In this paper, we first develop an experiment model of an SD-based real-time database system (SD-RTDBS). Then we investigate the feasibility of real-time transaction processing in the SD cluster using the experiment model. We also evaluate the cross effect of real-time transaction processing algorithms and SD cluster algorithms under a wide variety of database workloads.

A Network-Distributed Design Optimization Approach for Aerodynamic Design of a 3-D Wing (3차원 날개 공력설계를 위한 네트워크 분산 설계최적화)

  • Joh, Chang-Yeol;Lee, Sang-Kyung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.10
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    • pp.12-19
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    • 2004
  • An aerodynamic design optimization system for three-dimensional wing was developed as a part of the future MDO framework. The present design optimization system includes four modules such as geometry design, grid generation, flow solver and optimizer. All modules were based on commercial softwares and programmed to have automated execution capability in batch mode utilizing built-in script and journaling. The integration of all modules into the system was accomplished through programming using Visual Basic language. The distributed computational environment based on network communication was established to save computational time especially for time-consuming aerodynamic analyses. The distributed aerodynamic computations were performed in conjunction with the global optimization algorithm of response surface method, instead of using usual parallel computation based on domain decomposition. The application of the design system in the drag minimization problem demonstrated considerably enhanced efficiency of the design process while the final design showed reasonable results of reduced drag.

Implementation of a Cluster VOD Server and an Embedded Client based on Linux (리눅스 기반의 클러스터 VOD서버와 내장형에 클라이언트의 구현)

  • Seo Dongmahn;Bang Cheolseok;Lee Joahyoung;Kim Byounggil;Jung Inbum
    • Journal of KIISE:Computing Practices and Letters
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    • v.10 no.6
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    • pp.435-447
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    • 2004
  • For VOD systems, it is important to provide QoS to more users under the limited resources. To analyze QoS issues in real environment, we implement clustered VOD server and embedded client system based on the Linux open source platform. The parallel processing of MPEG data, load balancing for nodes and VCR like functions are implemented in the server side. To provide more user friendly interface, the general TV is used for a VOD client's terminal and the embedded board is used supporting for VCR functions. In this paper, we measure the performance of the implemented VOD system under the various user requirement features and evaluate the sources of performance limitations. From these analyses, we propose the dynamic admission control method based on the availability memory and network bandwidth. The proposed method enhances the utilization of the system resource for the more QoS media streams.

Dynamic Load Balancing Scheme Based on Resource Reservation for Migration of Agents in Pure P2P Network Environments (순수 P2P 네트워크 환경에서 에이전트 이주를 위한 자원 예약 기반 동적 부하 균형 기법)

  • Kim, Kyung-In;Kim, Young-jin;Eom, Young-Ik
    • The KIPS Transactions:PartA
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    • v.11A no.4
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    • pp.257-266
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    • 2004
  • Mobile agents are defined as processes which can be autonomously delegated or transferred among the hosts in a network in order to perform some computations on behalf of the user and co-operate with other agents. Currently, mobile agents are used in various fields, such as electronic commerce, mobile communication, parallel processing, search of information, recovery, and so on. In pure P2P network environment, if mobile agents that require computing resources rashly migrate to another peers without consideration on the peer's capacity of resources, the peer may have a problem that the performance of the peer is degraded due to lack of resources. To solve this problem, we propose resource reservation based load balancing scheme of using RMA(Resource Management Agent) that monitors workload information of the peers and that decides migrating agents and destination peers. In mobile agent migrating procedure, if the resource of specific peer is already reserved, our resource reservation scheme prevents other mobile agents from allocating the resource.

Load Balancing of Heterogeneous Workstation Cluster based on Relative Load Index (상대적 부하 색인을 기반으로 한 이기종 워크스테이션 클러스터의 부하 균형)

  • Ji, Byoung-Jun;Lee, Kwang-Mo
    • Journal of KIISE:Computing Practices and Letters
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    • v.8 no.2
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    • pp.183-194
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    • 2002
  • The clustering environment with heterogeneous workstations provides the cost effectiveness and usability for executing applications in parallel. Load balancing is considered a necessary feature for a cluster of heterogeneous workstations to minimize the turnaround time. Previously, static load balancing that assigns a predetermined weight for the processing capability of each workstation, or dynamic approaches which execute a benchmark program to get relative processing capability of each workstation were proposed. The execution of the benchmark program, which has nothing to do with the application being executed, consumes the computation time and the overall turnaround time is delayed. In this paper, we present efficient methods for task distribution and task migration, based on the relative load index. We designed and implemented a load balancing system for the clustering environment with heterogeneous workstations. Turnaround times of our methods and the round-robin approach, as well as the load balancing method using a benchmark program, were compared. The experimental results show that our methods outperform all the other methods that we compared.

A Hybrid Value Predictor using Speculative Update of the Predictor Table and Static Classification for the Pattern of Executed Instructions in Superscalar Processors (슈퍼스칼라 프로세서에서 예상 테이블의 모험적 갱신과 명령어 실행 유형의 정적 분류를 이용한 혼합형 결과값 예측기)

  • Park, Hong-Jun;Jo, Young-Il
    • Journal of KIISE:Computing Practices and Letters
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    • v.8 no.1
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    • pp.107-115
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    • 2002
  • We propose a new hybrid value predictor which achieves high performance by combining several predictors. Because the proposed hybrid value predictor can update the prediction table speculatively, it efficiently reduces the number of mispredicted instructions due to stale data. Also, the proposed predictor can enhance the prediction accuracy and efficiently decrease the hardware cost of predictor, because it allocates instructions into the best-suited predictor during instruction fetch stage by using the information of static classification which is obtained from the profile-based compiler implementation. For the 16-issue superscalar processors, simulation results based on the SimpleScalar/PISA tool set show that we achieve the average prediction rates of 73% by using speculative update and the average prediction rates of 88% by adding static classification for the SPECint95 benchmark programs.

KITTEN: A Multi-thread Virtual Reality System (KITTEN: 다중 스레드 가상현실 시스템)

  • Kim, Dae-Won;Lee, Son-Ou;Whon, Kwang-Yun;Lee, Kwang-Hyung
    • Journal of KIISE:Computing Practices and Letters
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    • v.6 no.3
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    • pp.275-287
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    • 2000
  • A virtual reality system must provide participants with a natural interaction, a sufficient immersion, and mostly, realistic images. To achieve this, it is crucial to provide a fast and uniform rendering speed regardless of the complexity of virtual worlds, or the complexity of simulation. In this paper, a virtual reality system which offers an improved rendering performance for complex virtual reality applications has been designed and implemented. The key idea of the proposed system is to exploit the multi-thread scheme in system module design, and execute each modules in parallel. Taking such design approach, rendering, simulation, and interaction can be executed independently. Hence, in applications where a simulation is complex or a scene is very large, this system can provide a more uniform and faster frame rates. The proposed method has been experimented under the various application environments in which scenes and simulations are very complex.

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Communication Schedule for GEN_BLOCK Redistribution (GEN_BLOCK간 재분산을 위한 통신 스케줄)

  • Yook, Hyun-Gyoo;Park, Myong-Soon
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.5
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    • pp.450-463
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    • 2000
  • Array redistribution is usually required to enhance algorithm performance in many parallel programs on distributed memory multicomputers. GEN_BLOCK redistribution, which is redistribution between different GEN_BLOCKs, is essential for load balancing. However, prior research on redistribution has been focused on regular redistribution, such as redistribution between different CYCLIC(N)s. GEN_BLOCK redistribution is very different from regular redistribution. Message passing in regular redistribution involves repetitions of basic message passing patterns, while message passing for GEN_BLOCK redistribution shows locality. This paper proves that two optimal condition, reducing the number of communication steps and minimizing redistribution size, are essential in GEN_BLOCK redistribution. Additionally, by adding a relocation phase to list scheduling, we make an optimal scheduling algorithm for GEN_BLOCK redistribution. To evaluate the performance of the algorithm, we have performed experiments on a CRAY T3E. According to the experiments, it was proven that the scheduling algorithm shows better performance and that the conditions are critical in enhancing the communication speed of GEN_BLOCK redistribution.

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Performance Improvement for PVM by Zero-copy Mechanism (Zero-copy 기술을 이용한 PVM의 성능 개선)

  • 임성택;심재홍;최경희;정기현;김재훈;문성근
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.5B
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    • pp.899-912
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    • 2000
  • PVM provides users with a single image of high performance parallel computing machine by collecting machines distributed over a network. Low communication overhead is essential to effectively run applications on PVM based platforms. In the original PVM, three times of memory copies are required for a PVM task to send a message to a remote task, which results in performance degradation. We propose a zero-copy model using global shared memory that can be accessed by PVM tasks, PVM daemon, and network interface card(NIC). In the scheme, a task packs data into global shared memory, and notify daemon that the data is ready to be sent, then daemon routes the data to a remote task to which it is sent with no virtual data copy overhead. Experimental result reveals that the message round trip time between two machines is reduced significantly in the proposed zero-copy scheme.

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A Study on Adaptive Parallel Computability in Many-Task Computing on Hadoop Framework (하둡 기반 대규모 작업처리 프레임워크에서의 Adaptive Parallel Computability 기술 연구)

  • Jik-Soo, Kim
    • Journal of Broadcast Engineering
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    • v.24 no.6
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    • pp.1122-1133
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    • 2019
  • We have designed and implemented a new data processing framework called MOHA(Mtc On HAdoop) which can effectively support Many-Task Computing(MTC) applications in a YARN-based Hadoop platform. MTC applications can be composed of a very large number of computational tasks ranging from hundreds of thousands to millions of tasks, and each MTC application may have different resource usage patterns. Therefore, we have implemented MOHA-TaskExecutor(a pilot-job that executes real MTC application tasks)'s Adaptive Parallel Computability which can adaptively execute multiple tasks simultaneously, in order to improve the parallel computability of a YARN container and the overall system throughput. We have implemented multi-threaded version of TaskExecutor which can "independently and dynamically" adjust the number of concurrently running tasks, and in order to find the optimal number of concurrent tasks, we have employed Hill-Climbing algorithm.