• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 추계학술대회 논문집
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• pp.291-296
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• 2001

The computerized automation of modern manufacturing system is tremendously important for the cost reduction. Recently, the automation is being realized by Computer Integrated Manufacturing (CIM) concept and the unmanned factory is the final goal of the automation. The automation of the low level of factory is the most crucial and difficult aspect in total CIM environment since various machines are involved. A cell is defined as a manufacturing group of closely related machineries in the entire factory hierarchy, The management scheme for a cell controller is defined from the software viewpoint. The domain of a cell is designed with tasks(processes) in a multiple-task operating system. The operation of the cell is established by defining schemes for overall control of the cell domain, databases, job scheduling, communications within the domain, user-interface and communications with outside machines. Although the software is developed in a specific operating system and WINDOW facilities, the operating strategies can be applied globally.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.163-165
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• 2008

휴전검토는 계통의 안정적인 운영과 신뢰도에 직접적으로 영향을 줄 수 있어 매우 중요한 업무라할 수 있다. 본 논문에서는 이러한 휴전검토 업무를 체계적이고 효율적으로 수행할 수 있는 휴전검토 종합시스템의 역할을 간단히 소개하고, 구성요소 중 하나인 휴전 일정 관리 및 검토 프로그램 설계에 대해 설명하고자 한다.

• 산업공학
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• 제9권2호
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• pp.159-171
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• 1996

In recent, most'of automobile industries adopt the concept of JIT production. According to the concept, the paternal manufacturers require their suppliers to supply parts just in time, so it is very important for a subcontractor to produce the parts in the appointed time of delivery. This study develops a production information system for Woosin Industry, which is one of such subcontractors of Hyundai Motors Company(HMC). The system is developed for use in Client/Server environment. In this study, the following three modules are developed, i. e., the production scheduling module, the sales management module to deal with the information about orders of HMC, delivery of parts, and bill collecting, and the module for supporting material requirements planning and purchase of material.

• Industrial Engineering and Management Systems
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• 제3권2호
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• pp.100-115
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• 2004

The network representation and branch and bound algorithm with efficient lower and upper bounding procedures are developed to determine a global optimal production schedule on a machine that minimizes sequence-dependent setup cost and earliness/tardiness penalties. Lower bounds are obtained based on heuristic and Lagrangian relaxation. Priority dispatching rule with local improvement procedure is used to derive an initial upper bound. Two dominance criteria are incorporated in a branch and bound procedure to reduce the search space and enhance computational efficiency. The computational results indicate that the proposed procedure could optimally solve the problem with up to 40 jobs in a reasonable time using a personal computer.

• 산업공학
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• 제18권1호
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• pp.63-72
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• 2005

In this paper, we present a distribution planning method for a supply chain. Like a typical distribution network of manufacturing firms, we have the form of arborescence. To consider more realistic situation, we investigated that an outside supplier has limited capacity. The customer demands are given in deterministic form in finite number of discrete time periods. In this environment, we attempt to minimize the total costs, which is the sum of inventory holding and backorder costs over the distribution network during the planning horizon. To make the best of the restricted capacity, we propose the look-ahead feature. For looking ahead, we convert this problem into a single machine scheduling problem and utilize tabu search approach to solve it. Numerous simulation tests have shown that the proposed algorithm performs quite well.

• 대한산업공학회지
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• 제36권2호
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• pp.78-86
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• 2010

The traveling purchaser problem(TPP) is a generalization of the well-known traveling salesman problem(TSP), which has many real-world applications such as purchasing the required raw materials for the manufacturing factories and the scheduling of a set of jobs over some machines, and many others. TPP also could be extended to the vehicle routing problem(VRP) by incorporating additional constraints such as multi-purchaser, capacity, distance and time restrictions. In the last decade, TPP has received some attention of the researchers in the operational research area. However it has not received the equivalent interest as much as TSP and VRP. Therefore, there does not exist a review of the TPP. The purpose of this paper is to review the TPP and to describe solution procedures proposed for this problem. We also introduce the ILP formulation for the multiple TPP(mTPP) which is generalized type of TPP. We compare the system performance according to change from TPP to mTPP.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.117-135
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• 2016

Performance enhancement is one of the most important issues in high performance distributed computing systems. In such computing systems, online users submit their jobs anytime and anywhere to a set of dynamic resources. Jobs arrival and processes execution times are stochastic. The performance of a distributed computing system can be improved by using an effective load balancing strategy to redistribute the user tasks among computing resources for efficient utilization. This paper presents a multi-class load balancing strategy that balances different classes of user tasks on multiple heterogeneous computing nodes to minimize the per-class mean response time. For a wide range of system parameters, the performance of the proposed multi-class load balancing strategy is compared with that of the random distribution load balancing, and uniform distribution load balancing strategies using simulation. The results show that, the proposed strategy outperforms the other two studied strategies in terms of average task response time, and average computing nodes utilization.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2012년도 한국컴퓨터종합학술대회논문집 Vol.39 No.1(D)
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• pp.216-218
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• 2012

최근 센서 네트워크의 제약적 전력 공급 문제를 해결하기 위한 하나의 방법으로 에너지 수급 센서 기술이 연구되고 있다. 에너지 수급 센서의 수급 효율은 가변적인 환경에 의존하기 때문에 수급률을 고려한 저전력 통신 기법이 요구된다. 또한 다중 우선순위 데이터가 존재하는 네트워크에선 에너지 수급률과 배터리 잔량을 고려한 차별적인 데이터 처리가 필요하다. 이에 본 논문에서는 각 계층들이 에너지 소모에 미치는 영향을 고려하며 동시에 높은 우선순위 데이터의 빠른 처리를 가능하게 하는 패킷 스케쥴링 기법 및 에너지 관리 방법을 제안하고 이를 수학적 모델링을 통해 분석할 것이다.

• 자원ㆍ환경경제연구
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• 제11권3호
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• pp.447-463
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• 2002

The heat demand prediction is an essential issue in management of district heating system. Without an accurate prediction through the lead-time period, it might be impossible to make a rational decision on many issues such as heat production scheduling and heat exchange among the plants which are very critical for the district heating company. The heat demand varies with the temperature as well as the time nonlinearly. And the parametric specification of the heat demand model would cause a misspecification bias in prediction. A nonparametric model for the short-term heat demand prediction has been developed as an alternative to avoiding the misspecification error and tested with the actual data. The prediction errors are reasonably small enough to use the model to predict a few hour ahead heat demand.

• 시스템엔지니어링학술지
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• 제10권2호
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• pp.43-50
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• 2014

The Centralized Traffic Control(CTC) System of Urban Railway is an element(subsystem) of the Urban Railway system to aim safety operation and efficient management of rolling stock in accordance with a train scheduling program in train operation ways. That's why the CTC System must be developed considering systematic and safety-guaranteed methods such as RAMS(Reliability, Availability, Maintainability, and Safety) refereed to IEC standards. The CTC System is consists of rolling stock, signaling, power supply, communication, and mechanical equipment and preforms control and remote monitoring functions. The technical activities considering safety process are very important at such an early stage of development in a railway project. This paper introduces RAMS activities and an independent safety assessment by $3^{rd}$ Party focused on a safety applied to a development of the CTC system of Urban Railway and proposes the experiences as well practices.