• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.137-154
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• 1999

In this paper, we propose a software design method that will track the effects of modifications in a component to the rest of the components in the design phase. The prediction of the effects due to the design modifications before coding can be a valuable aid for the complex and large software development. Within the method, the target system is represented by the structured I/O system level specification which is one of the system representation level defined by the system theory. Then it is abstracted to the I/O system level. The DEVS (Discrete Event System Specification) model is constructed based on tile I/O system level specification. Finally, the DEVS model is simulated to generate the behavior of the software by the abstract simulator in DEVS simulation environment. As an application, the graphic user interface system of a metal grating production scheduling system is presented.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.31
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• pp.99-114
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• 1994

The introduction of new equipments to strengthen the competitiveness of enterprises is one of pretty important factors. Enterprises introducing new equipments strengthen competitiveness through productivity increasing, high quality maintenance, inventory reduction, improved design and production interface, simple scheduling process, low scrap rate, rework reduction, etc. Managers will work out the best equipment-replacing strategy through the appropriate combination of potential cost attributes and qualitative attributes difficult to quantify in accordance with the business purpose. This study is to present a method to select an equipment-replacing alternative through the decision-making model of Analytic Hierarchy Process in consideration of the differences of cost flow of the alternatives, taking into consideration tangible attributes and strategic intangible attributes.

• Journal of Korean Institute of Industrial Engineers
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• v.34 no.3
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• pp.296-307
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• 2008

A semiconductor production system has sophisticated manufacturing operations and needs high capital investment for its expensive equipment, which warrants efficient real-time flow control for wafers. In the bay, we consider material handling equipment that can handle multiple carriers of wafers. The dispatching logic first determines the transportation time of each carrier to its destination by each unit of transportation equipment and uses this information to determine the destination machine and target carrier. When there is no available buffer space at the machine tool, the logic allows carriers to stay at the buffer of a machine tool and determine the delay time, which is used to determine the destination of carriers in URL. A simulation study shows this dispatching logic performs better than the procedure currently in use to reduce the mean flow time and average WIP of wafers and increase efficiency of material handling equipment.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.77-89
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• 1991

One of the important problems concerning the efficient operation of an automated manufacturing system is the flow control problem. Most research papers about scheduling and control of a FMS consider fabrication, machining and assembly independently. In this paper an effective flow control strategy for a FMS with an assembly subsystem which may be called FMAS (Flexible Machining and Assembly System) is designed using the operation-oriented and, combined Push and Pull control method. The flow control system to be described here could meet production demands with a minimum makespan while satisfying assigned due-dates and keeping a low volume of work-in-process at the same time. The control mechanism also considers machine failures and rush jobs.

• Journal of the Korea Safety Management & Science
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• v.5 no.2
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• pp.155-164
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• 2003

In this regard, the newly focused logistics information system makes reducing the expenses of whole logistic available by cutting down the expenses of materials, transportation and stock and also, it allows the company to cut down the procurement expense through the reduced lead-time and rationalize producing plans by eliminating the uncertain orders and fluctuation in procurement. It further more optimizes the efficiency of over all productions by meeting the dead line for delivery to the customers. In the recent environment of globalization where fierce competitions exist between manufacturers, logistics plays important role in the strategies of companies, and managements of companies try their best efforts in establishing the strategy to accomplish the innovative relationship between supply chain channels. Therefore, in this study, we try to suggest the model of consolidated logistics system that is integrated logistics information system with suggesting the better way of logistics and comparative analysis with logistics system to resolve the difficulties numbers of companies face after realizing what logistics information system is in Korea.

• Proceedings of the Safety Management and Science Conference
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• 2010.04a
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• pp.219-230
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• 2010

Remarkably improvements have occurred recently in the maintenance management of physical assets and productive systems, so that less wastages of energy and resources occur. The technology of maintenance is about finding and applying cost-effective ways of avoiding or overcoming performance deterioration. Maintenance is thus a vital support function in business, especially as increasingly large investments are being required in physical assets. TPM(Total Productive Maintenance) focuses on optimizing planning scheduling. Availability, performance and quality rate are other factors that affect productivity. Especially there are some losses that affect the overall equipment effectiveness(OEE). These losses lead to low values of OEE, which provides an indication of how effective the production precess is. This study explores the ways in which Korean small and medium manufacturing industries can improve OEE.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.566-569
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• 2004

본 연구에서는 생산능력의 제한이 있는 다계층(multi-echelon) 공급사슬에서의 효과적인 분배계획수립을 목적으로 한다. 수요 정보는 계획 기간(planning horizon) 동안 확정적인 형태로 주어지고 이러한 상황 하에서 전체 공급사슬에서 발생하는 재고유지 비용(holding cost)과 재고이월 비용(backorder cost)의 합을 최소화하는 분배 문제의 해법을 제시하고자 한다. 본 연구에서는 총비용을 최소화하는 각 노드별 분배량을 결정하기 위해서 look-ahead 기법을 사용한다. Look-ahead 기법을 통해 분배 계획 수립 시 해당 기간의 수요 정보뿐만 아니라 미래 수요를 함께 반영함으로써 생산능력 제한에 효과적으로 대처할 수 있도록 하였다. Look-ahead 기법을 적용하기 위해 본 문제를 단일 기계 일정계획(single machine scheduling) 문제로 전환하고 이에 대한 효율적인 발견적 기법을 제시한다. 또한 제안된 발견적 기법의 성능을 평가하기 위해 다양한 실험 조건하에서 제안된 알고리듬과 기존의 미래 수요를 고려하지 않는 계층 재고 정책(echelon stock policy)의 결과를 비교하여 본 연구의 우수성을 입증하였다.

• Korean Management Science Review
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• v.24 no.1
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• pp.35-43
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• 2007

Minimizing the total number of setup changes of a machine increases the throughput and improves the stability of a production process, and as a result enhances the product qualify. In this context, we consider a new product-mix problem that minimizes the total number of setup changes while producing the required quantities of a product over a given planning horizon. For this problem, we develop a mixed integer programming model. Also, we develop an efficient heuristic algorithm to find a feasible solution of good quality within reasonable time bounds. Computational results show that the developed heuristic algorithm finds a feasible solution as good as the optimal solution in most test problems.

• Journal of the Korea Safety Management & Science
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• v.3 no.1
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• pp.35-44
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• 2001

Today's environment of enterprise is changing. They have to face customers' demands with the right product, the right service and supply them at the right time. And aIso cut down logistics and inventory cost and bring up the Profit as much as they can. This means the change of putting enterprise first in importance to putting customer first in importance. therefore to correspond to customer's demand, shorting lead time is becoming a essential condition. The answer to this changes of environment is supply chain management In this study, we use Goldratt's drum-buffer-rope scheduling in between manufacturer and supplier. And when shortage of inventory occur, search for the supply chain's CCR. Pressing CCR for more production, and supply Inventory from logistic center to guide for inventory buffing. using logistic warehouse between manufacturer and supplier, can execute function of buffer.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.67
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• pp.103-110
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• 2001

The BOM(Bill Of Material) contains various important information for establishing production scheduling and purchasing process. For effective and efficient constructing of the BOM, some methods, such as, conventional BOM, Modular BOM and Generic BOM are developed. Many companies input the BOM information with manual process. During this process, no one can avoid human errors, that is input error and to omit input necessary Information. We must to remove the possibility of these human errors, and to construct BOM effectively. To do this, we try to take the BOM from CAD data automatically We have developed a supporting system for extracting BOM from AutoCAD files.