• 대한산업공학회지
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• 제25권4호
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• pp.411-420
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• 1999

A mixed model production line is a production line where a variety of product models are produced. In U-shaped production lines (called U-lines) used in just-in-time production system, the strategy of mixing product models is often used to provide various types of products to customers in time. Line balancing and model sequencing problems are important for an efficient use of mixed model U-lines. Although the two problems are tightly interrelated with each other, prior researches have considered them separately or sequentially. This paper presents a new method using a coevolutionary algorithm that can solve the two problems at the same time. To promote diversity and search efficiency, in this paper the evolutionary system is based on the localized interactions within and between populations. Methods of selecting environmental individuals and evaluating fitness are developed. Efficient genetic representations and operator schemes are also provided. When designing the schemes, we take into account the features specific to the problems. The experimental results demonstrate that the proposed algorithm is superior to existing approaches.

• 대한안전경영과학회지
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• 제6권2호
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• pp.115-125
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• 2004

This paper presents a new method that can efficiently solve the integrated problem of line balancing and model sequencing in mixed-model U-lines (MMULs). Balancing and sequencing problems are important for an efficient use of MMULs and are tightly related with each other. However, in almost all the existing researches on mixed-model production lines, the two problems have been considered separately. A genetic algorithm for balancing and sequencing in mixed-model U line is proposed. A presentation method and genetic operators are proposed. Extensive experiments are carried out to analyze the performance of the proposed algorithm. The computational results show that the proposed algorithm is promising in solution quality.

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3863-3869
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• 2009

최근 자동차산업에서의 시장의 세계화와 증가하는 고객의 까다로운 욕구는 다양한 제품의 증가와 제조업체가 공급해야 하는 생산라인의 다양한 방식의 증가로 이어지게 되었다. 또한, 자동차 생산시스템의 모듈화는 자동차부품 공급업체들의 생산시스템에도 많은 영향을 미치고 있다. 이러한 변화는 혼합형 모델 조립라인이라 불리는 비용 효율적이고 유연한 생산시스템의 구현을 요구하고 있다. 본 논문에서는 이러한 혼합형 모델 조립에서 발생하는 여러 문제점들과 이러한 조립오류를 방지할 수 있는 기술에 대해 살펴보고, 혼합형 모델 자동차부품 조립라인에서 RFID를 이용한 오류방지 모니터링시스템을 개발하였다. 특히, 자동차부품 조립현장에서 일어나는 부품의 잘못된 설치와 누락과 같은 문제점들을 최소화하기 위하여 RFID를 이용한 모니터링시스템을 개발함으로써 문제점을 해결하고 조립오류를 예방하여 기존의 시스템을 보완하고자 하였다.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2002년도 춘계학술대회
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• pp.91-97
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• 2002

In this thesis presents line balancing problems of two-sided and mixed model assembly line widely used in practical fields using genetic algorithm for reducing throughput time, cost of tools and fixtures and improving flexibility of assembly lines. Two-sided and mixed model assembly line is a special type of production line where variety of product similar in product characteristics are assembled in both sides. This thesis proposes the genetic algorithm adequate to each step in tow-sided and mixed model assembly line with suitable presentation, individual, evaluation function, selection and genetic parameter. To confirm proposed genetic algorithm, we apply to increase the number of tasks in case study. And for evaluation the performance of proposed genetic algorithm, we compare to existing algorithm of one-sided and mixed model assembly line. The results show that the algorithm is outstanding in the problems with a larger number of stations or larger number of tasks.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.90-97
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• 2014

Nash Cournot Equilibrium (NCE) has been widely used in a competitive electricity market to analyze generation firms' strategic production quantities. Congestion on a transmission network may lead to a mixed strategy NCE. Mixed strategy is complicated to understand, difficult to compute, and hard to implement in practical market. However, Stackelberg model based equilibrium does not have any mixed strategy, even under congestion in a transmission line. A guide to understanding mixed strategy equilibrium is given by analyzing a cycling phenomenon in the players' best choices. This paper connects the concept of leader-follower in Stackelberg model with relations between generation firms on both sides of the congested line. From the viewpoint of social welfare, the surplus analysis is presented for comparison between the NCE and the Stackelberg equilibrium (SE).

• 대한안전경영과학회지
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• 제4권2호
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• pp.83-101
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• 2002

In this thesis presents line balancing problems of two-sided and mixed model assembly line widely used in practical fields using genetic algorithm for reducing throughput time, cost of tools and fixtures and improving flexibility of assembly lines. Two-sided and mixed model assembly line is a special type of production line where variety of product similar in product characteristics are assembled in both sides. This thesis proposes the genetic algorithm adequate to each step in tow-sided and mixed model assembly line with suitable presentation, individual, evaluation function, selection and genetic parameter. To confirm proposed genetic algorithm, we apply to increase the number of tasks in case study. And for evaluation the performance of proposed genetic algorithm, we compare to existing algorithm of one-sided and mixed model assembly line. The results show that the algorithm is outstanding in the problems with a larger number of stations or larger number of tasks.

• 산업공학
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• 제10권3호
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• pp.209-216
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• 1997

This mixed push and pull production system defines that all stages are not ordered by either of the production systems. Some stages are ordered by a push-type production system and the other stages are ordered by a pull-type production system. A decision support system is built by using a combination of optimization program and the "tunable" SIMAN discrete-event simulation for the implementation of an optimally mixed production system. Finding this optimal system requires 6 CPU hours for the case study on a Pentium. Both the simulation and optimization model are validated with a case study of Phoenix company that manufactures transmitters. This paper uses survey from experts in this company for evaluation and validation of this system.

• 한국경영과학회지
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• 제26권4호
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• pp.109-124
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• 2001

This paper presents a new method that can efficiently solve the integrated problem of line balancing and model sequencing in mixed model assembly lines (MMALs). Line balancing and model sequencing are important for an efficient use of MMALs. The two problems of balancing and sequencing MMALs are tightly related with each other. However, In almost all the existing researches on mixed-model production lines, the two problems have been considered separately. In this research, an endosymbiotic evolutionary a1gorithm, which is a kind of coevolutionary a1gorithm, is adopted as a methodology in order to solve the two problems simultaneously. This paper shows how to apply an endosymbiotic evolutionary a1gorithm to solving the integrated problem. Some evolutionary schemes are used In the a1gorithm to promote population diversity and search efficiency. The proposed a1gorithm is compared with the existing evolutionary algorithms in terms of solution quality and convergence speed. The experimental results confirm the effectiveness of our approach.

• 한국시뮬레이션학회논문지
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• 제22권2호
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• pp.93-100
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• 2013

다품종 소량생산이 보편화 되면서 하나의 생산라인에서 여러 종류의 제품을 교대로 생산하는 혼류생산방식이 보편화 되었다. 하지만 흐름라인 방식의 혼류생산에서는 필연적으로 작업장 간의 공정시간 불균형이 존재한다. 따라서 이러한 공정불균형에 의한 대기의 낭비를 최소화하기 위하여 기존의 흐름생산방식에서 셀생산방식으로 전환하는 시도가 빈번하게 발생한다. 본 논문에서는 굴삭기 부품을 생산하는 혼류흐름라인 방식의 자동화 로봇 용접라인을 FMC 개념의 직선형 셀방식으로 전환하는 과정에서 타당성 검토를 위해 시뮬레이션을 수행한 사례연구 결과를 소개한다. 분석결과 26.7%의 생산량 증가와 55% 이상의 리드타임 감소효과가 예상되었다. 또한 향후 제품 생산비율의 변화에 따른 민감도분석을 수행하였다.

• 한국시뮬레이션학회논문지
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• 제11권4호
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• pp.69-80
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• 2002

This study deals with the productivity improvement on a flow production system with the consideration of line-balancing. In a flow production system, similar product models are produced on a same assembly line, the predefined process order and the limitation of total worker number. The system can be increased the work-in -process(WIP) inventory and the worker's idle time. In this study, the worker assignment model is developed to assign evenly workload of process to each product model in such a manner that each process has the different number of worker. This worker assignment model is the mathematical model that determines worker number in each process such that the idle time of processes is reduced and the utilization of worker is improved. We use a simulation technique to simulate the production line proposed by the mathematical model and apply real production line. With the result of simulation, this study analyzes the propriety of production line and proposes the alternatives of new production line