• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.463-467
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• 2007

CFD(Computational Fluid Dynamics)는 수치 기법(Numerical)과 알고리즘을 사용하여 유체 유동 문제를 풀고 해석하는 것이다. 본 논문에서는 이러한 CFD 분석 프로그램의 효율적인 수행을 위해 분산 환경을 기반으로 하는 메타컴퓨팅(Metacomputing) 시스템에 대해서 기술한다. 실제 CFD 프로그램을 단일 클러스터 시스템에서 수행시켰을 때와 메타컴퓨팅 시스템을 이용하여 수행시켰을 때 소요되는 시간과 결과 파일을 실험을 통하여 비교한다. 그 결과 메타컴퓨팅 시스템을 이용하여 CFD 분석 프로그램을 분산 수행시킨 경우는 그렇지 않은 경우에 소요되는 시간보다 평균 $15.3{\sim}38.5%$ 정도 빨랐고, 동일한 결과를 얻을 수 있음을 확인하였다.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.137-148
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• 2012

In this paper, we proposed the location-aware coordinate routing algorithm for improving the performance of routing algorithm by using ZigBee in Smart Grid environment. A distributed address allocation scheme used an existing algorithm that has wasted in address space. The x, y and z coordinate axes from divided address space of 16 bit to solve this problems. However, coordinate routing does not take account of wireless link condition. If wiress link condition is not considered, when the routing table is updated, the nodes with bad link conditions are updated in the routing table and can be chosen as the next hop. This brings out the retransmissions because of received packet's errors. Also, because of these retransmissions, additional power is consumed. In this paper, we propose the location-aware coordinate routing algorithm considering wiress link condition, where reliable data transmission is made and the consumed enegy is minimize. and we compared and connected region and transition region of ZigBee location based routing in the aspect of average number of multi hops, subordinate packet delivery ratio, delay time, and energy consumption of proposed algorithm. It turned out that there were improvements in performances of each items.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.606-607
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• 2008

환경문제에 대한 관심이 전 세계적인 이슈로 고조됨에 따라 여러 산업의 패러다임에도 큰 변화가 요구되고 있다. 특히 지구 온난화 문제의 심각성에 의해 선진국을 주축으로 온난화의 주범인 화석연료 사용을 줄이려는 노력이 나타나고 있다. 이에 따라 화석연료를 주로 사용하는 전력산업에서도 친환경적 에너지인 신재생에너지를 보급하기 위한 노력들이 늘어나고 있다. 따라서 본 논문은 신재생에너지를 포함한 분산전원을 효과적으로 운영할 수 있는 마이크로그리드 시스템의 관점에서 환경비용 및 운용방식을 고려한 경제성 평가를 시행하였다. 경제성 평가는 여러 가지 경우를 고려하여 최적화 프로그램인 GAMS를 이용하여 모의하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06b
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• pp.436-441
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• 2010

분산 및 그리드 환경에서의 워크플로우 기술은 현재까지 지속적으로 발전하고 있으며, 최근에는 이러한 기술을 유비쿼터스 컴퓨팅 환경에 적용하려는 시도가 이루어지고 있다. 이러한 환경에서의 서비스 제공자는 다양한 상황 정보들을 인식하여 사용자에게 최적의 서비스를 제공 할 수 있어야 한다. 그러나 기존 워크플로우 기반의 상황인지 미들웨어들은 단일 워크플로우 서비스를 제공하는 수준에 머물러 있다. 이에 기존 시스템들은 다양하고 복합적인 서비스를 제공하는데 한계가 있다. 이를 위해 본 논문에서는 확장된 CAWL을 바탕으로 다중 워크플로우 서비스를 처리하고 제공할 수 있는 상황인지 다중 워크플로우 처리기를 제안한다. 제안하는 처리기는 상황인지를 기반으로 다수의 사용자에게 복합적인 워크플로우 서비스를 동시에 제공하며, 동시에 진행하는 병렬서비스의 흐름을 처리할 수 있다.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.229-239
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• 2008

A Distributed File System (DFS) provides a mechanism in which a file can be stored across several physical computer nodes ensuring replication transparency and failure transparency. Applications that process large volumes of data (such as, search engines, grid computing applications, data mining applications, etc.) require a backend infrastructure for storing data. And the distributed file system is the central component for such storing data infrastructure. There have been many projects focused on network computing that have designed and implemented distributed file systems with a variety of architectures and functionalities. In this paper, we describe a complete distributed file system which can be used in large-scale search-oriented systems.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.461-465
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• 2003

Grid-computing on networked computers is increasingly applied to the variety of large-scale computation problem. Several software systems are developed for providing the application programmers with computers available. However, these systems are not web-based systems, lacks a collaborative environment or do not supply the real-time visualization facility. Web technology is become the general technology on the development of network application, in particular, because the interface can be made platform independent. In this paper, we propose the web-based framework for executing the parallel SPMD application written MPI. Also, a web-based collaborative environment is development with a real-time visualization technology.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.573-574
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• 2015

스마트그리드 전력계통시스템 기술의 중요한 특징중의 하나는 국제표준을 기본으로 탑재하고 있다. 발전소부터 수용가까지 각 영역별로 운영중인 시스템들이 국제표준을 준수한다는 것은 어떤 특정임무만을 담당하는 독립된 시스템이 아닌 타 시스템에 정보를 주고 받는 분산시스템의 구조로 전력시스템 전체 아키텍쳐가 변화하고 있는 것이다. 이러한 환경은 ICT(Information & Communication Technology)와 매우 친화적이며 스마트그리드의 발전을 촉진시킨다. 전력회사마다 운영중인 송변전자동화시스템인 SCADA(Supervisory Control And Data Acquisition)에 대하여 IEC 61970 표준을 지원하는 기능을 갖춘 제품들이 세계시장에 급속히 공급되고 있어 표준을 기반으로 하는 이기종 제품간에 정보교환의 호환성을 검증하는 상호운용성 시험의 중요성이 커지고 있는 실정이다. 본 논문에서는 IEC 61970이 적용된 SCADA 시스템을 대상으로 표준기반의 상호운용성 시험에 대해 기술하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.871-874
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• 2010

Needs for Smart Grid development are increasing all over the world as a solution to its problem according to depletion of energy resources, climatic and environmental rapidly change and growing demand for electrical power. Especially decentralized power is attracting world's attention. In this mood a new era for a unit scale of decentralized power environment is on its way in building. However there is a problem to have to be solved in the uniformity of power quality because the amount of power generated from renewable energy resources such as wind power and solar light is very sensitive to climate fluctuation. And thus this paper tries to suggest an energy management method on basis of real time monitoring for meteorological data. In the current situation of lacking in USN-based killer application in Smart Grid field, this paper proposes the USN-based DER management system which collects the meteorological data and control power system througout utilizing wireless sensor network technique this business. This communication technique is regarded to be efficient in aspects of installation cost and tits maintenance cost. The proposed EMS model embodies the method for predicting the power generation by monitoring and analyzing the climatic data and controling the efficient power distribution between the renewable energy and the existing power. The ultimate goal of this paper is to provide the technological basis for achieving zero-energy house.

• Smart Media Journal
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• v.8 no.2
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• pp.9-15
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• 2019

Since the computational complexity for hologram generation increases exponentially with respect to the size of the point cloud, parallel processing using CUDA and/or OpenCL library based on multiple GPUs has recently become popular. The CUDA kernel for parallelization needs to consist of threads, blocks, and grids properly in accordance with the number of cores and the memory size in the GPU. In addition, in case of multiple GPU environments, the distribution in grid-by-grid, in block-by-block, or in thread-by-thread is needed according to the number of GPUs. In order to evaluate the performance of CGH generation, we compared the computational speed in CPU, in single GPU, and in multi-GPU environments by gradually increasing the number of points in a point cloud from 10 to 1,000,000. We also present a memory structure design and a calculation method required in the CUDA-based parallel processing to accelerate the CGH (Computer Generated Hologram) generation operation in multiple GPU environments.

• Journal of IKEEE
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• v.23 no.1
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• pp.289-294
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• 2019

At present, domestic small islands mainly supply electric power using diesel generators. However, diesel generators can cause instability of the power system due to slow response on power load fluctuation, and cause environmental problems due to the emission of carbon gas by using fossil fuels. In order to overcome this problem, this paper proposes a method to establish an optimal microgrid by introducing solar power, wind power, and energy storage device to Chujado Island, which is supplied with electric power through a diesel generator. The economical optimum capacity of each distributed power source is calculated by using HOMER (Hybrid Optimization Model for Multiple Energy Resources) program and the proposed microgrid is validated by using PSCAD/EMTDC (Power Systems Computer Aided Design/ Electromagnetic Transients including DC) program which can analyze system stability.