• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.699-706
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• 2005

증가하는 소비의 추세, 한정된 자원, 폐기물 처분등의 문제로 인하여, remanufacturing 에 대한 관심이 더욱 높아져가고 있다. Remanufacturing 에 대한 생산계획 및 스케줄링은 높은 불확실성으로 인하여 기존의 방법들과 별개로 다루어져야 한다. 본 연구에서는 manufacturing/remanufacturing 생산 시스템에서의 생산계획을 위한 수정된 유전 알고리즘(GA)을 제안하였다. GA 의 chromosome 은 각 부품의 생산 수준을 의미하며, 알고리즘을 이용하여 중간조립품과 최종제품의 분해/조립 계획을 결정할 수 있다. 임의로 생성된 문제들에 대해 실험한 결과, 다양한 문제들에 대하여 적용 가능하다는 것을 알 수 있었다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.523-527
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• 2005

현재 기업에서는 생산 효율을 극대화시키기 위하여 많은 비용을 투자하여 Package형태의 솔루션(S/W)을 도입하고 있다. 그러나 솔루션들은 그 특성상 기업특성을 생산 일정계획 수립에 충분히 반영하지 못하고 있어 실제 도입 후에 사용에 어려움이 겪고 있으며 일부 기업에서는 생산일정 전문가를 통하여 재생산계획을 수립하고 있다. 본 연구는 상용화 되고 있는 솔루션에서 제시된 생산일정을 생산일정 전문가가 회사의 특성을 고려하여 재생산일정을 수립하는 단계에 대한 사용자의 패턴을 추출 후 신경망을 통하여 패턴을 학습하여 재생산일정 수립 시 소요되는 시간을 최소화 시키며 기업의 특성을 반영하는 적응적 일정계획 지원 시뮬레이터의Framework을 제시하고자 한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.207-214
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• 2005

Productivity and quality stability are very important competitive factors in PCB manufacturing lines that process the multiple types of products with the mixed process flows under frequent order information changes. MES is an appropriate IT solution to solve these problems in the medium-sized PCB manufacturing company. This paper introduces the MES development and its effects for a medium-sized PCB manufacturing company. The main functions of an implemented MES are delivery simulation, production scheduling, and production process monitoring. Productivity are improved up to $10{\sim}20%$ and manufacturing lead times per order are shortened up to 2 days according to the manufacturing scenarios.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.2
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• pp.17-29
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• 1999

The manufacturing systems have to cope with the circumstance that the requirements of customers are changed abruptly and the life cycle of product becomes short. In this paper, to develop the efficient control and operation of autonomous, distributed machining systems the concept of Holonic Manufacturing System is adopted and methods for the control and operation of the system are proposed including an evaluation function for the negotiation between holons. And it is applied to scheduling and selection of operations to be worked with consideration of quality. It is expected that the proposed methods may be applied to operate autonomous, distributed machining systems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.162-173
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• 1993

항공기 운항계획은 항공사의 계획업무 중 핵심적인 문제로 운항편수와 항공기 출발시간 그리고 운항할 항공기의 기종을 결정하는 문제이다. 본 연구에서는 이익을 최대로 하는 운항계획을 수립하기 위한 새로운 최적해법을 제안한다. 일반적으로 항공기 운항계획은 대규모의 정수 선형계획 문제이기 때문에 기존의 정수 최적해법으로 최적해를 계산하기가 쉽지 않다. 본 연구에서는 모든 결정변수를 사용하지 않고 필요에 따라 일부분의 결정변수만을 생성하여 선형 최적해를 계산하는 열 생성 최적해법을 제안한다. 이 해법을 이용하여 대규모 정수계획인 운항계획의 최적해를 매우 효율적으로 계산할 수 있는 해법을 제안한다. 실제 항공기 운항계획에 본 연구에서 제안하는 최적해법을 적용한 결과를 보여 그 효율성이 월등함을 보인다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.201-204
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• 1997

This study is focussed on optimization problems which require allocating the restricted inventory to demand points and assignment of vehicles to routes in order to deliver goods for demand sites with optimal decision. This study investigated an integrated model using three step-by-step approach based on relationship that exists between the inventory allocation and vehicle routing with restricted amount of inventory and transportations. we developed several sub-models such as; first, an inventory-allocation model, second a vehicle-routing model based on clustering and a heuristic algorithms, and last a vehicle routing scheduling model, a TSP-solver, based on genetic algorithm. Also, for each sub-models we have developed computer programs and by a sample run it was known that the proposed model to be a very acceptable model for the inventory-allocation and vehicle routing problems.

• Proceedings of the Safety Management and Science Conference
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• 2005.11a
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• pp.30-39
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• 2005

Line capacity calculation has been used to determine optimum efficiency and safe train service for train scheduling plan and investment priority order throughout detecting bottleneck section. Because of some problems of Yamagisi and UIC methods for line capacity calculation, developing of the method of line capacity calculation and evaluation for the Korea circumstance is important. This paper deals with the integrated system of TPS(Train Performance Simulator), PES(Parameter Evaluation Simulator), LCS (Line Capacity Simulator) and sensitivity analysis for line capacity calculation model.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.256-259
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• 2007

Multicast and Broadcast Service (MBS) provides flexible and efficient transmission of the same information to multiple users using shared radio resources on WiBro network. The advantage of this service is to achieve the most efficient use of radio and network resources as well as to lessen sender's processing load when sending the same information to multiple users. Though radio resources are saved since a multicast or broadcast transport connection is associated with a service flow, it is hard to change MBS service channel dynamically. In this paper, we propose a Radio Resource Management System (RRMS) for supporting dynamic scheduling of MBS service channels. Results show that our proposed scheme using Radio Resource Allocation Table (RRAT) can efficiently support MBS services by providing dynamic schedule for MBS service channels.

• Korean Management Science Review
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• v.17 no.2
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• pp.125-134
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• 2000

Keeping the promised delivery date for a customer order is crucial for a company to promote customer satisfaction and generate further businesses. For this, a company should be able to quote the delivery date that can be achieved with the capacity available on the shop floor. In a dynamic make-to-order manufacturing environment, the problem of determining a delivery date for an incoming order with consideration of resource capacity, workload, and finished-product inventory can hardly be solved by an analytical solution procedure. This paper considers a situation in which a delivery date for a customer order is determined based on a job schedule, and presents the SimTriD algorithm that provides the best scheduling for determining a delivery date of customer order through the job schedule that efficiently utilizes manufacturing resources with consideration of interacting factors such as resource utilization, finished-product inventory, and due date.

• IE interfaces
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• v.23 no.2
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• pp.139-146
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• 2010

In this paper, we present the study of a real passenger transportation system. Passenger transportation problem aims to transport passengers from bus stops to their destinations by a fleet of vehicles while satisfying various constraints such as vehicle capacity, maximum allowable riding time in a bus, and time windows at destinations. Our problem also has special issues such as mixed loading, consideration of afternoon problem together with morning problem, and transferring passengers between vehicles. Our solution approach consists of three serial procedures: bus route generation, bus scheduling, and post optimization. Efficient heuristic algorithms were developed and implemented for the procedures. The proposed solution approach has been successfully applied to several real world problem instances and could reduce about 10% to 15% of buses.