• Smart Structures and Systems
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• 제3권3호
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• pp.299-320
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• 2007

Smart sensors densely distributed over structures can provide rich information for structural monitoring using their onboard wireless communication and computational capabilities. However, issues such as time synchronization error, data loss, and dealing with large amounts of harvested data have limited the implementation of full-fledged systems. Limited network resources (e.g. battery power, storage space, bandwidth, etc.) make these issues quite challenging. This paper first investigates the effects of time synchronization error and data loss, aiming to clarify requirements on synchronization accuracy and communication reliability in SHM applications. Coordinated computing is then examined as a way to manage large amounts of data.

• 한국경영과학회지
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• 제39권4호
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• pp.19-31
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• 2014

We study parallel processing techniques for the R programming language of high performance computing technology. In this study, we used massively parallel computing system which has 25,408 cpu cores. We conducted a performance evaluation of a distributed memory system using MPI and of a the shared memory system using OpenMP. Our findings are summarized as follows. First, For some particular algorithms, parallel processing is about 150 times faster than serial processing in R. Second, the distributed memory system gets faster as the number of nodes increases while shared memory system is limited in the improvement of performance, due to the limit of the number of cpus in a single system.

• Journal of information and communication convergence engineering
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• 제6권3호
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• pp.348-352
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• 2008

In distributed computing paradigm, mobile surrogate systems migrates from on host in a network to another. However, Mobile surrogate system have not gained wide acceptance because of security concerns that have not been suitably addressed yet. In this paper, we propose a security framework based on Grid Proxy Gateway for mobile Grid service. The current Grid Security Infrastructure is extended to mobile computing environments. The surrogate host system designed for mobile Personal Digital Assistant (PDA) users can access the certified host and get his proxy credential to launch remote job submission securely.

• International Journal of Contents
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• 제7권2호
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• pp.1-5
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• 2011

Allocation of computing resources is a crucial issue when dealing with a huge number of tasks to be completed according to a given deadline and cost constraints. The task scheduling to several resources (e.g. grid, cloud or a supercomputer) with different characteristics is not trivial, especially if a trade-off in terms of time and cost is considered. We propose an allocation approach able to fulfill the given requirements about time and cost through the use of optimizing techniques and an adaptive behavior. Simulated productions of tasks have been run in order to evaluate the characteristics of the proposed approach.

• 인터넷정보학회논문지
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• 제4권5호
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• pp.51-60
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• 2003

비동기 반복 알고리즘은 부하 불균형 및 컴퓨터 노드 간의 전송 지연에 의한 병렬 알고리즘의 성능 저하를 완화하는 하나의 방법인데, 이는 노드들 간의 비대칭적 데이터 전송을 필요로 한다 본 논문에서는 분산 메모리 시스템 상에서 MPMD 방식으로 노드당 별도의 서버 프로세스를 추가로 생성하여 비대칭적 전송을 구현하고, 노드당 하나의 프로세스를 생성하는 SPMD 방식과 비교하며 그 장단점에 대해 논의한다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2001년도 춘계학술발표논문집 (상)
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• pp.111-114
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• 2001

기존의 멀티미디어 메일은 대용량 메일이라 개인 사용자에게 그 부담이 크지 않을 수가 없었다. 본 연구에서는 멀티미디어 스트림엔진인 Essence 를 이용하여 동영상 멀티미디어 메일을 전송하는데 필요한 Essence 내에 데이터베이스를 지원하기 위한 DBMedium 개발과 데이터베이스 라이브러리를 개발하기 위한 일련의 과정을 제안하고 있다.

• ETRI Journal
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• 제44권2호
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• pp.313-326
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• 2022

This study presents a noble scheme for distributed and parallel simulations with optimized agent placement for simulation instances. The traditional parallel simulation has some limitations in that it does not provide sufficient performance even though using multiple resources. The main reason for this discrepancy is that supporting parallelism inevitably requires additional costs in addition to the base simulation cost. We present a comprehensive study of parallel simulation architectures, execution flows, and characteristics. Then, we identify critical challenges for optimizing large simulations for parallel instances. Based on our cost-benefit analysis, we propose a novel approach to overcome the performance constraints of agent-based parallel simulations. We also propose a solution for eliminating the synchronizing cost among local instances. Our method ensures balanced performance through optimal deployment of agents to local instances and an adaptive agent placement scheme according to the simulation load. Additionally, our empirical evaluation reveals that the proposed model achieves better performance than conventional methods under several conditions.

• 대한토목학회논문집
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• 제26권4A호
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• pp.689-692
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• 2006

본 연구에서는 분산된 시스템 안에서 네트워크를 이용하여 다량의 자료와 데이터를 동시에 공유할 수 있을 뿐만 아니라 원격지에서도 실시간으로 실험이 가능한 건설실험시설의 분산공유에 따른 실질적인 연구현황과 이에 따른 문제점을 그리드컴퓨팅을 이용하여 분석하였다. 이로써, 향후 건설실험시설의 인프라 구축에 있어 분산공유에 대한 데이터의 처리와 공유를 가능하게 하는 시스템구축의 실질적인 방향을 제시하고자 하며, 분산된 다양한 데이터를 다수의 사용자에게 동시에 공유할 수 있는 건설실험시설의 인프라를 구축하는데 기여하고자 한다.

• 인터넷정보학회논문지
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• 제2권1호
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• pp.13-21
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• 2001

본 논문에서는 인터넷상에 연결된 유휴자원을 이용한 분산 웹 환경에서 각 시스템 상에 저장된 지식을 공유·재이용 하기 위한 온톨로지 다중화 연구를 수행한다. 온톨로지의 다중화란 동일지식에 의하여 구축된 온톨로지를 다른 온톨로지와 지식공유가 가능하도록 변환하는 것이다. 본 연구에서는 이러한 분산웹 온톨로지 다중화 시스템을 구성하기 위하여 분산웹 환경구축방안과 함께 지식의 공유 및 재 이용을 위한 다중 온톨로지 구성이라는 두 가지 관점 하에서 접근한다. 구성된 시스템은 지니기술을 이용하여 이기종간의 확장성과 효율성을 지닌 웹 컴퓨팅환경을 구축하였고, 또한 분산작업을 통하여 분산 웹 환경 하에서의 다중 온톨로지간의 실질적인 지식변환과정이 잘 전개됨을 볼 수 있다.

• Journal of Communications and Networks
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• 제17권6호
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• pp.558-567
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• 2015

In recent years, we have seen a proliferation of mobile-network-enabled smart objects, such as smart-phones and smart-watches, that form a cyber-physical integrated network to connect the cyber and physical worlds through the capabilities of sensing, communicating, and computing. Discovery of the relationship between smart objects is a critical and nontrivial task in cyber-physical integrated network applications. Aiming to find the most stable relationship in the heterogeneous and dynamic cyber-physical network, we propose a distributed and efficient relationship-discovery algorithm, called dynamically maximizing remaining unchanged time with minimum connected dominant set (DMRUT-MCDS) for constructing a backbone with the smallest scale infrastructure. In our proposed algorithm, the impact of the duration of the relationship is considered in order to balance the size and sustain time of the infrastructure. The performance of our algorithm is studied through extensive simulations and the results show that DMRUT-MCDS performs well in different distribution networks.