• 산업공학
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• 제18권1호
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• pp.22-34
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• 2005

This paper introduces a simulation model which is based on the process analysis of a semiconductor company. The objective of the simulation modelis not only to estimate the overall performancesof the company but also to evaluate the performances of various operation rules for shop floor control. First, in order to develop the simulation model, a time study is performed for each process after analyzing the processes for the company. Second, by using ARENA, a simulation model is constructed based on the process analysis and the time study. After the simulation model is tested and run, its results are discussed.

• 산업경영시스템학회지
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• 제45권1호
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• pp.83-90
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• 2022

This study deals with replacement analysis of deteriorated equipment for improving productivity of production system. Frequent breakdown of the deteriorated equipment causes a situation that reduces productivity such as low product quality, process delay, and repair cost. However, the replacement of new equipment will be required a high initial investment cost, so it is important to analysis the economic feasibility. Therefore, we analyze the effect of the production system due to the aging effect of the equipment and the feasibility of equipment replacement based on the economic analysis. The process flow, working time, logistics movement, etc. are analyzed in order to build the simulation modeling for a ship and land switchboard production system. Using numerical examples, the economic feasibility analysis of equipment replacement through replacement of existing deteriorated equipment and additional arrangement of new facilities is performed.

• 산업경영시스템학회지
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• 제44권2호
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• pp.140-152
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• 2021

During the shift from gasoline vehicles to electric ones, auto parts manufacturing companies have realized the importance of improvement in the manufacturing process that does not require any layout changes nor extra investments, while maintaining their current production rate. Due to these reasons, for the auto part manufacturing company, I-company, this study has developed the simulation model of the PUSH system to conduct a process analysis in terms of production rate, WIP level, and logistics work's utilization rate. In addition, this study compares the PUSH system with other three manufacturing systems -KANBAN, DBR, and CONWIP- to compare the performance of these production systems, while satisfying the company's target production rate. With respect to lead-time, the simulation results show that the improvement of 77.90% for the KANBAN system, 40.39% for the CONWIP system, and 69.81% for the DBR system compared to the PUSH system. In addition, with respect to WIP level, the experimental results demonstrate that the improvement of 77.91% for the KANBAN system, 40.41% for the CONWIP system, and 69.82% for the DBR system compared to the PUSH system. Since the KANBAN system has the largest impacts on the reduction of the lead-time and WIP level compared to other production systems, this study recommends the KANBAN system as the proper manufacturing system of the target company. This study also shows that the proper size of moving units is four and the priority allocation of bottleneck process methods improves the target company's WIP and lead-time. Based on the results of this study, the adoption of the KANBAN system will significantly improve the production process of the target company in terms of lead-time and WIP level.

• 산업경영시스템학회지
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• 제46권1호
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• pp.68-75
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• 2023

In an automotive plant, an automated storage and retrieval system (ASRS) synchronizes material handling flows from a part production line to an auto-assembly line. The part production line transfers parts on small-/large-sized pallets. The products on pallets are temporarily stored on the ASRS, and the ASRS retrieves the products upon request from the auto-assembly line. Each ASRS aisle is equipped with narrow-/wide-width racks for two pallet sizes. An ASRS aisle with narrow-/wide-width racks improves both storage space utilization and crane utilization while requiring delicate ASRS aisle design, i.e., the locations of the narrow-/wide-width racks in an ASRS aisle, and proper operation policies affect the ASRS performance over demand fluctuations. We focus on operation policies involving a common storage zone using wide-width racks for two pallet sizes and a storage-retrieval job-change for a crane based on assembly-line batch size. We model a discrete-event simulation model and conduct extensive experiments to evaluate operation policies. The simulation results address the best ASRS aisle design and suggest the most effective operation policies for the aisle design.

• 한국농공학회논문집
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• 제47권2호
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• pp.35-44
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• 2005

While the need for analyzing and interpreting agricultural logistics are becoming more and more prominent with the rapid changes within the agricultural environment, previously mathematical models have been proved to have its limitations due to the unpredictable traits of agriculture itself and finding the adequate simulation model is not easy. Therefore, in this research, the tank model that has been used to analyze the rainfall-runoff in watersheds, was used to develop a logistics model for estimating shipment by agricultural production. The model was certified by wholesale market data of garlic.

• 대한조선학회논문집
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• 제51권6호
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• pp.510-520
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• 2014

Unlike other mass production in small variety, shipbuilding process is a project-based method in single variety, which causes unpredictable volatility in the planning system. In shipyards, series of manufacturing processes from fabrication to erection is sequentially carried out. In order to predict unfavorable changes such as overload or low load of working volume, computerized simulation has been being gradually adopted. The data used in the simulation are processed from the database of the main scheduling and planning system. Thus the quality of those data is very crucial for the meaningful results. Unfortunately, research on the verification of data quality is very rare and hardly known to the authors. In this work, using the database of scheduling and product information system of a large domestic shipyard, the data required for the simulation are qualitatively analyzed and verified.

• 한국융합학회논문지
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• 제11권11호
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• pp.41-46
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• 2020

4차산업혁명의 시작은 국내 산업 전반에 다양한 변화를 가져오고 있으며, 생산 제조 및 물류 분야의 기업에 스마트 팩토리가 확산되면서, 자동화 설비를 사용하고 있다. 특히 물류 자동화 현장에서는 AGV가 널리 사용되고 있으며, 전통적인 AGV의 구동 방식인 라인 유도 방식의 사용이 대부분이다. 또한 AGV 시스템 개발자 및 시스템 운영자 및 관리자, 유지보수 인력의 수요도 증가하고 있는 추세이나, 교육을 위한 시스템의 설치에 고가의 비용이 소요되고, 넓은 공간을 필요로 하는 특성을 가지고 있어, 체계적인 교육이 어려운 상황이다. 본 논문에서는 교육생들의 원활한 실습을 위하여 가상 시뮬레이션 기반의 AGV 원격 교육 모델을 제안한다. 제안 모델은 기존 기술인 라인 유도 방식이 아닌 영상 정보를 분석하여 AGV를 구동할 수 있는 모델로 구성하였으며, 자가진단 평가 결과 기존 기자재를 활용한 통제 집단 보다 온라인 교육을 통한 실험 집단이 평균 0.65의 만족도가 상승하여, 온라인 교육 환경에서 활용할 수 있는 가능성을 확인하였다.

• 한국기계가공학회지
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• 제12권6호
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• pp.175-181
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• 2013

The primary element of machining automation is to maximize the utilization of machine tools, which determines the output and lead-time. In particular, 95% of raw materials for wing ribs are cut into chips and 0.6 ton of chips are generated every hour from each machine tool. In order to verify the chip recycling system that controls the chips from the machines in five-axis FMS line, a simulation of the virtual model is constructed using the QUEST simulation program. The optimum speed of the chip conveyor and its operating conditions that directly affect the efficiency of the FMS line are presented including the chip conveyor speed, the maximum capacity of the hopper, and the number of chip compressors.

• 산업기술연구
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• 제39권1호
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• pp.27-31
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• 2019

Semiconductor logistics systems are facing difficulties in increasing production as production processes become more complicated due to the upgrading of fine processes. Therefore, the purpose of the research is to design predictive models that can predict traffic during the pre-planning stage, identify the risk zones that occur during the production process, and prevent them in advance. As a solution, we build FABs using automode simulation to collect data. Then, the traffic prediction model of the areas of interest is constructed using deep learning techniques (keras - multistory conceptron structure). The design of the predictive model gave an estimate of the traffic in the area of interest with an accuracy of about 87%. The expected effect can be used as an indicator for making decisions by proactively identifying congestion risk areas during the Fab Design or Factory Expansion Planning stage, as the maximum traffic per section is predicted.

• Journal of Construction Engineering and Project Management
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• 제4권2호
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• pp.31-40
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• 2014

The management of vehicular supply of "perishable" construction material, such as concrete mixes, faces a series of uncertainties such as weather, daily traffic patterns and accidents. Presented in this paper is a logistics control model for managing a hauling fleet with interrelated processes at both ends and queue capacities. Discrete event simulation is used to model the complex interactions of production units and the randomness of the real world. Two alternative strategies for ready mix concrete delivery, with and without an off-site waiting queue, are studied to compare supply performance. Secondly, the paper discusses the effect of an agent-based GPS tracking system providing real-time travel data that lessens the uncertainty of trucking time. The results show that the combination of GPS information with off-site queuing reduces productivity loss and process wastes of concrete placement as well as the idleness of supply trucks when crew or pump experience an unexpected stoppage.