• 대한기계학회논문집B
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• 제30권8호
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• pp.756-763
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• 2006

PEMFC has several technical problems such as water management, long term stability and performance degradation as. PEMFC has been studied not only to solve water management, but also to generate power in stable manner to system by using a hybrid system with auxiliary energy storage device. The purpose of this study is to couple PEMFC with supercapacitor to make a hybrid system and to design and test control strategies for stable power generation in case of changing output power. The polarization curve and dynamic behaviors while changing power were investigated to find out characteristics of PEMFC stack. A DC/DC converter was fabricated in order to increase fuel cell and supercapacitor voltage and to charge supercapacitor. We found that the operation strategy 2 was recommended to the system because of solving water management problem and increasing the dynamic behavior.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1996년도 추계학술대회발표논문집; 고려대학교, 서울; 26 Oct. 1996
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• pp.49-52
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• 1996

In this article, we develop a 'dynamic' approach to manufacturing improvement, based on perspectives of manufacturing learning and decision theory. First, we present an alternative definition of production system consistent with a decision-theoretic perspective: the system consists of structural, infra-structural, and decision making constructs. A primary proposition is that learning capability possessed by a manufacturing system be prerequisite for the system to improve its manufacturing performance through optimal controlling of the three constructs. To support the proposition, we elaborate on a mathematical representation of "learning" as defined in an applied setting. We show how the learning capability acts as an integrating force ameliorating the trade-off between two key manufacturing capabilities, i.e., process controllability and process flexibility.exibility.

• 디지털산업정보학회논문지
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• 제12권4호
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• pp.13-24
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• 2016

Defense Acquisition Program Administration's weapon system software development and management guideline specifies the criteria of software reliability tests including static and dynamic tests mainly on C/C++ languages. Recently, Defense Acquisition Program Administration expanded the scope of software reliability test for the various languages including C#, java etc. but specific criteria for them are not established. This study suggests the reliability test procedures and standards on C# programming software in weapon system. For the static test, considering the nature of the C# which depends on .NET framework, this paper introduces applying coding rules recommended by Microsoft Corp. Visual Studio 2012. Block coverage provided by Visual Studio is applied on dynamic tests and the achievement objectives for block coverage according to the software levels(A, B, C) are suggested. Also, the software reliability test procedures and standards proposed by this paper are properly verified through the case study. The result of this study can be used for establishing the specific criteria of the software reliability test for C# programming software in weapon system.

• 산업경영시스템학회지
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• 제31권2호
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• pp.19-27
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• 2008

This paper addresses determining the location of the distribution centers in a discrete dynamic distribution system. In discrete and finite time horizon, the demands of retailers are dynamic for the periods. Some locations among the retailers can be chosen for the role of the distribution centers at the beginning of each period. The distribution centers have to be located at the location of minimizing logistics cost. Logistics cost factors are the operation cost and the fixed cost of distribution center, and the transportation cost. The distribution centers of minimizing sum of operation cost, fixed cost and transportation cost are determined among retailers in each period for the planning period. A mathematical model was formulated and a dynamic programming based algorithm was developed. A numerical example was shown to explain our problem.

• Journal of Information Processing Systems
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• 제2권3호
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• pp.183-188
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• 2006

A RMON agent system, which locates on a subnet, collects the network traffic information for management by retrieving and analyzing all of the packets on the subnet. The RMON agent system can miss some packets due to the high packet analyzing overhead when the number of packets on the subnet is huge. In this paper, we have developed a light-weight RMON agent system that can handle a large amount of packets without packet loss. Our RMON agent system has also been designed such that its functionality can be added dynamically when needed. To demonstrate the dynamic reconfiguration capability of our RMON agent system, a simple port scanning attack detection module is added to the RMON agent system. We have also evaluated the performance of our RMON agent system on a large network that has a huge traffic. The test result has shown our RMON agent system can analyze the network packets without packet loss.

• 조명전기설비학회논문지
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• 제25권8호
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• pp.70-81
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• 2011

In this paper, a multi-agent control system for DC-coupled photovoltaic (PV), fuel cell (FC), ultracapacitor(UC) and battery hybrid power system is studied for commercial buildings & apartment buildings microgrid. In this proposed system, the PV system provides electric energy to the electrolyzer to produce hydrogen for future use and transfer to the load side, if possible. Whenever the PV system cannot completely meet load demands, the FC system provides power to meet the remaining load. A multi-agent system based-power management and control algorithm is proposed for the hybrid power system by taking into account the characteristics of each power source. The main works of this paper are hybridization of alternate energy sources with FC systems using long and short storage strategies to build the multi-agent control system with pragmatic design, and a dynamic model proposed for a PV/FC/UC/battery bank hybrid power generation system. A dynamic simulation model for the hybrid power system has been developed using Matlab/Simulink, SimPowerSystems and Stateflow. Simulation results are also presented to demonstrate the effectiveness of the proposed multi-agent control and management system for building microgrid.

• 한국수소및신에너지학회논문집
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• 제26권2호
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• pp.184-191
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• 2015

As the power electronics system increases the frequency, the power loss and thermal management are paid more attention. This research presents a real time model of dissipation power with junction temperature response for 120kw IGBT inverter which is applied to the thermal management of high power IGBT inverter. Since the computational time is critical for real time simulation, look-up tables of IGBT module characteristic curve are implemented. The power loss from IGBT provides a clue to calculate the temperature of each module of IGBT. In this study, temperature of each layer in IGBT is predicted by lumped capacitance analysis of layers with convective heat transfer. The power loss and temperature of layers in IGBT is then communicated due to mutual dependence. In the dynamic model, PWM pulses are employed to calculation real time IGBT and diode power loss. Under Matlab/Simulink$^{(R)}$ environment, the dynamic model is validated with experiment. Results showed that the dynamic response of power loss is closely coupled with effective thermal management. The convective heat transfer is enough to achieve proper thermal management under guideline temperature.

• 산업공학
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• 제19권1호
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• pp.1-8
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• 2006

The mobile communication network has to offer good quality of services (QoS), high capacity, and more coverage at a lower cost. However, with the increase of cellular user, the shortage of capacity due to unbalanced call distribution and lack of QoS are common. This paper deals with dynamic sectorization for efficient resource management to solve load unbalancing among microcells in CDMA (Code Division Multiple Access) microcellular system. Dynamic load balancing can be effected by grouping micro-cells properly and grouping can be developed through a routing mechanism. Therefore, we use ants and their routes to choose the optimum grouping of micro-cells into sectors using Multiple Ant Colony System (MACS)in this paper.

• 한국화재소방학회논문지
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• 제14권4호
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• pp.23-28
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• 2000

반도체 공장의 제연설계를 위한 성능기준 설계를 분석하였다. 사례분석을 통하여 제연 설계 시스템의 성능평가 기준을 설정하고 최적의 배연 방법을 분석하기 위한 FDS 화재모델링을 수행하였다. 제연 설계 지침이나 관련 법규 또는 표준화된 기준이 부족한 한국과 미국의 현실에서 본 연구의 성능기준 설계 방법은 반도체공장의 제연 설계를 위한 현실적인 적용과 활용이 기대된다.

• 융합정보논문지
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• 제7권5호
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• pp.169-175
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• 2017

회계정보시스템은 회계자료를 취합 처리하여 의사결정자에게 가치 있는 정보를 제공한다. 그러나 최근의 급속한 환경변화에 있어 지속경영으로서의 회계정보시스템은 성과를 최적화하기 위한 조직의 필요성에 적합되어야 한다. 동적 회계정보시스템의 역량은 회계처리와 조직의 성과를 향상시킬 것으로 기대한다. 동적역량틀(Dynamic capabilities framework:DCF)을 이용함으로서 동적인 회계정보시스템의 역량은 세 가지 관점에서 시너지효과를 발휘할 수 있는 것으로 기대한다. 1) 유연한 회계정보시스템, 2) 보완적인 비즈니스 지능시스템 및 3) 정보기술 자산을 통한 회계 전문화의 세 가지 영역의 시너지효과를 발휘할 수 있을 것이다. 본 연구를 통하여 동적 회계정보시스템 역량, 회계처리 성과 및 기업성과의 상관성을 검증하고자 한다. 연구결과, 동적 회계정보시스템 자원을 개발함으로써 조직의 가치를 더할 수 있는 것으로 나타났다. 본 연구는 회계정보시스템 환경의 성과산출에 지렛대 역할을 할 수 있는 가이드를 제공할 수 있다.