• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.181-192
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• 2010

We develop a dispatching policy for stochastic scheduling simulation especially for a continuous manufacturing system with machine breakdowns. The proposed dispatching policy computes an urgency index with the consideration of re-heating, setup cost and remaining due date. Prioritized by the index, we execute swapping or reassigning material sequences so as to minimize the total penalty cost. To evaluate the performance of the proposed policy, a discrete event simulation is developed. With 200 data sets and 20 iterations, we compare the performance of the urgency policy with those of SPT (Shortest Processing Time) and FCFS (First Come First Serve) which are the most common policies. The result shows that the proposed policy consistently gives the lowest total costs by reducing the penalty costs for lateness.

• Journal of the Korea Society for Simulation
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• v.28 no.3
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• pp.25-40
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• 2019

Today, container terminals are fiercely competing to attract an increasing number of containers. As a way to improve terminal productivity, this study proposes two dispatching rules for yard truck allocation priorities. First, Multi-Attribute Dispatching Rule(MADR) is an allocation method to calculate the weighted sum of multiple factors affecting container terminal productivity and priority them. Especially, the workload of the quay crane was considered one of the factors to reduce the residence time of the ship. Second, Cycling Dispatching Rule(CDR) is the effective way to increase the number of double cycles that directly affect terminal productivity. To identify the effects of combinations of pooling and dispatching, a comparative experiments was performed on 8 scenarios that combined them. A simulation environment has been developed for experiments and the results have demonstrated that the combination of terminal level pooling and Multi-attribute Dispatching could be an excellent combination in KPIs consisting of GCR and delayed departure of ships, etc.

• IE interfaces
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• v.22 no.1
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• pp.73-84
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• 2009

In this paper, we propose a dispatching algorithm for constructing a Factory Operating System (FOS) which can operate semiconductor fabrication factories more efficiently and effectively. We first define ten dispatching criteria and propose two methods to apply the defined dispatching criteria sequentially and simultaneously (i.e. fixed dispatching architecture). However the fixed type methods cannot apply the criteria adaptively by considering changes in the semiconductor fabrication factories. To overcome this type of weakness, an adaptive dispatching architecture is proposed for applying the dispatching criteria dynamically based on the factory status. The status can be determined by combining evaluation results from the following three status criteria; target movement, workload balance, and utilization rate. Results from the shop floor in past few periods showed that the proposed methodology gives a good performance with respect to the productivity, workload balance, and machine utilization. We can expect that the proposed adaptive dispatching architecture will be used as a useful tool for operating semiconductor fabrication factories more efficiently and effectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1838-1855
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• 2008

The manufacturing industry seeks for improvements in efficiency at the manufacturing process. This paper presents a method for effective real time dispatching for parallel machines with multi product that minimizes mean tardiness and maximizes the quality of the product. What is shown in this paper is that using the Rolling Horizon Tabu search method in the real time dispatching process, mean tardiness can be reduced to the minimum. The effectiveness of the method presented in this paper has been examined in the simulation and compared with other dispatching methods. In fact, using this method manufacturing companies can increase profits and improve customer satisfaction as well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.1095-1100
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• 2010

Customer satisfaction is a main issue in the modern competitive industrial environment. So quality and productivity are the most important requisites. This paper presents a method for effective real time dispatching for parallel machines with multi product that minimizes mean tardiness and maximizes the quality of the product. In this paper, the effectiveness of the method has been examined in the simulation and compared with other dispatching methods. Using this method presented in this paper, companies can improve customer satisfaction.

• Journal of the Korea Society for Simulation
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• v.23 no.4
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• pp.97-109
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• 2014

Personal rapid transit (PRT) is a new transportation system, which is energy efficient and brings high quality of customer service. Customers arrive dynamically at stations and request transportation service. In this paper, we propose a new online PRT dispatching algorithm for pickup and delivery of customers. We adopt the nearest neighbor dispatching rule, which is known as performing well in general. We extend the rule with bipartite matching in order to deal with multiple vehicles and customers at the same time. We suggest a systematic way for selecting vehicles that will be considered to be dispatched, since the scope with which vehicles are selected may affect the system performance. We regard the empty travel distance of vehicles and the customer waiting time as the performance measures. By using simulation experiments, it has been examined that the scope of dispatching affects the system performance. The proposed algorithm has been validated by comparing with other dispatching rules for transportation services. We have shown that our algorithm is more suitable for PRT operating environment than other dispatching rules.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.829-835
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• 2008

The objective of this study is to present the two-step dispatching strategy for the purpose of the transport vehicle with multi-function used in container terminal. The two-step dispatching is a method to save the waiting time between transport vehicle and cranes using real time location control. The first step dispatching is to allocate the destination location based on the real time location information. The second step dispatching is to indicate the specific job such as loading, unloading, and pick-up based on the condition of working area. This two-step dispatching strategy decreases the waiting times of the stevedoring system and will contribute at a productivity improvement in container terminal.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.385-386
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• 2022

Currently, global developed countries in shipping and logistics establish smart ports by introducing various digital technologies such as automated terminals and sharing platforms. This means that the importance of efficiency throughout the port by improving resource utilization efficiency and minimizing work idle time is increasing. Therefore, this study proposes a yard truck dispatching method of improving resource utilization efficiency. And we analyze the problems of the existing dispatching rules and develop Y/T dispatching algorithm that comprehensively considers related constraints. In addition, the simulation takes into account the terminal congestion based on the operation data of the Busan New Port, it is conducted using the existing dispatch method and developed Y/T dispatching algorithm. And the operational effects of analysis result are evaluated.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.3
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• pp.37-44
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• 2004

국내 반도체 산업은 불과 20년도 안 되는 짧은 기간동안에 괄목할만한 성장을 하여 전세계 반도체 생산 규모 면에서 3위 국가로 부상하였으며, 기술 경쟁력 면에서도 한국인의 자존심을 그나마 지켜왔다. 하지만, 반도체 제조는 가장 복잡한 제조공정의 하나로 분류되며, 이러한 복잡한 시스템을 통제하기 위해서는, 다양한 시스템 조건 하에서 적절한 생산전략을 마련하는 것이 필요하다. 그러나, 반도체 제조 시스템에 대한 다양한 상황과 관련한 연구는 많지 않다. 반도체 제조공정 시스템에 대한 스케줄은 생산공정의 재진입, 공정의 높은 불확실성, 급속하게 변하는 제품과 기술과 같은 특성 때문에 반도체 제조공정 시스템에 대한 스케줄은 복잡하고 어려운 작업이며, 사이클타임의 절감 및 단위시간당 생산량의 증대와 같은 시스템 목적을 달성하기 위하여, 반도체 제조 시스템에 대한 좋은 방법을 발견하기 위한 많은 연구가 있었다. 반도체 산업의 생산 흐름은 가장 독특한 특징을 가지고 있으며 생산계획과 반도체 제조의 스케줄링과 계획을 어렵게 하고 있다. 현재 반도체 조립공정에서 수행되고 있는 일정계획은 단순 FCFS (First Come First Serve)에 의한 할당규칙에 따른다. 또한 Backlog(예비재고)를 1일 생산량을 기준으로 Buffer로 운영하고 있다. 따라서 본 연구에서는 효율적인 재고관리와 정확한 스케줄링이 생산의 경쟁력 확보 우위임을 가정하여 다양한 할당규칙(dispatching rule)을 실시간 적용하여 정확한 일정계획 수립의 효과와 결과를 시뮬레이션을 통해 검증하고자 한다. 제시된 방법론을 위하여 시뮬레이션 접근방법이 사용되었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3232-3238
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• 2010

As flexible manufacturing systems (FMSs) are highly automated and required flexibility to satisfy market need, dispatching rules are constrained by specific environments of manufacturing systems such as mechanical failures, absence of employees, and lack of spare parts. In this paper, an ontology-based knowledge approach is proposed to improve efficiency of system through adapting suitable dispatching rules, considering context in a FMS shop floor, which consists multiple manufacturing cells. the multi-agents monitor manufacturing system status and job so that it figures out a dispatching rule considering context. To demonstrate the proposed approach, a proof-of-concept prototype system has been implemented in the $JADE^{TM}$ platform and Protege to make OWL DL ontology.