• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.537-541
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• 2003

The synchronization of production-delivery artivities is one of crucial factors to get competitive collaboration benefits between the manufacturer and the retailor(s). There were several researches to study on He optimal delivery policy to minimize the total cost of integrated system of both manufacturer and retailor(s). In this research, we investigate the joint optimal shipment policy in case that a manufacturer produces multiple products sharing a single production facility in the manufacturer side and retailor(s) deploys JIT delivery pattern with equal-size shipment policy. We formulate this problem as a form of 'Common Cycle Approach' in classical ELSP (Economic Lot Scheduling Problem) and provide simple optimal solution procedure.

• 산업공학
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• 제15권1호
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• pp.99-106
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• 2002

A recently developed alternative to traditional production planning and control systems such as material requirement planning(MRP) and just-in-time(JIT) is the drum-buffer-rope(DBR). The DBR now being implemented in growing number of manufacturing organizations enables better scheduling and decision making on the shop floor. In implementing the DBR, however, an information system is usually needed to transmit the signal that runs from the constraint to material release. In this paper we propose a different mechanism to transmit the signal in the case that the demand of product is stable, which uses the well-known Kanban system. To improve the reality, this paper shows and example of the Kanban format, its operation, and calculation of the number of Kanbans.

• 지역연구
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• 제8권1호
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• pp.119-130
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• 1992

Many of the industrialized countries since the 1970s have been experiencing the change in the industrial structure due to technological development, that is, from Fordism to post-Fordism, or to "flexible production system". Regional development has been undergoing some changes according to the different industrial production systems. During the Fordist mass production period, the manufacturing belt was the core region of the production system. As the system shifts to flexible production system of which characteristics are veritcal disintegration, emphasis for JIT(just-in-time) delivery system, part-time and short-time labor contracts, design-intensive industries, etc, the new system requires the new production core and has produced the new industrial spaces, such as Sunbelt cities, suburbs, small-or medium-sized cities, and non-metropolitan areas. In the perspective of global system, the Fordist production system made th NICs developed, because the mass production required many unskilled and low-wage workers. As the NICs exports of manufactured goods have incredibly expanded during the 1970s, the industrialized countries have become threatened. The industriablized countries have restructured their economies and international policies. Such restructures resulted in the economic depression of the NICs. The investment pattern of the industrialized countries has changed and particularly those industries adopting the Post-Fordism have invested from the NICs to the peripheral areas of their own countries or toward the underdeveloped countries which have much lower wage workers. The investment pattern of the NICs is also undergoing some changes like from metropolitian areas to small or non-metropolitan regions. The regional development since the post-Fordist production is still going on, thus it is not possible to generalize the tendency. That could be a particular phenomenon or a stage in the long-term cycle. But the regional development in the world system since 1980s definitely shows the different pattern.t pattern.

• 산업공학
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• 제6권1호
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• pp.99-112
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• 1993

This study deals with analysis of material from in Tube manufacturing line. This line is a multi product flow ship type production line, which consists of 5 steps of work station. Some work stations involve in unnecessary moving activities of workers and much work in-process storage due to the non-systematic material flow with respect to the different lot size production of multi-items. To improve productivity for this line, one alternative is considered such as grouping two work stations by using GT and JIT concepts. Also, feasibility analysis for this alternative is performed using and simulation model built by SIMAN IV simulation language.

• 산업경영시스템학회지
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• 제38권3호
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• pp.78-86
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• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• 산업경영시스템학회지
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• 제40권1호
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• pp.79-86
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• 2017

This research focused on deciding optimal manufacturing WIP (Work-In-Process) limit for a small production system. Reducing WIP leads to stable capacity, better manufacturing flow and decrease inventory. WIP is the one of the important issue, since it can affect manufacturing area, like productivity and line efficiency and bottlenecks in manufacturing process. Several approaches implemented in this research. First, two strategies applied to decide WIP limit. One is roulette wheel selection and the other one is elite strategy. Second, for each strategy, JIT (Just In Time), CONWIP (Constant WIP), Gated Max WIP System and CWIPL (Critical WIP Loops) system applied to find a best material flow mechanism. Therefore, pull control system is preferred to control production line efficiently. In the production line, the WIP limit has been decided based on mathematical models or expert's decision. However, due to the complexity of the process or increase of the variables, it is difficult to obtain optimal WIP limit. To obtain an optimal WIP limit, GA applied in each material control system. When evaluating the performance of the result, fitness function is used by reflecting WIP parameter. Elite strategy showed better performance than roulette wheel selection when evaluating fitness value. Elite strategy reach to the optimal WIP limit faster than roulette wheel selection and generation time is short. For this reason, this study proposes a fast and reliable method for determining the WIP level by applying genetic algorithm to pull system based production process. This research showed that this method could be applied to a more complex production system.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.294-296
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• 1996

JIT(just-in-time) 생산시스템은 제조라인의 재공품 재고량을 최소화하고, 필요한 품목을 적시에 필요한 양만큼만 생산하여 공급하는 것을 목적으로 한다. 이러한 시스템은 사용하는 칸반의 수에 따라 single-card kanban system과 two-card kanban system으로 구별할 수 있다. 또한 각 공정이 입력버퍼(input buffer)와 출력버퍼(output buffer)를 갖는 경우와 공정간에 하나의 버퍼를 갖는 경우로 나누어 볼 수 있다. 본 연구는 기계간의 물류(material handling)가 필요한 시점에 즉시 이루어진다는 가정하에 기계간 버퍼가 하나이고, 그 버퍼의 용량이 1인 경우의 single-card kanban의 효율적인 운용방안을 개발하였다. 본 연구의 목적은 생산지시칸반의 회수시기를 적절히 조절하여 생산라인의 이용효율(utilization)을 극대화하고자 하는 것이다. 칸반회수시기 결정을 위한 상황분석의 범위를 10대의 기계로 제한하여 시뮬레이션에 의해 분석하였다. 기존의 칸반운영방식과 생산라인에서의 재고를 최소화하는 운영 알고리듬, 그리고 생산기계의 효율을 최대화할 수 있는 운영 알고리듬을 개발하여 비교.분석하였다.

• 한국컴퓨터정보학회논문지
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• 제6권1호
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• pp.95-102
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• 2001

오늘날 공급사슬경영(Supply Chain Management)은 우리나라뿐만 아니라 전 세계적으로 기업경영의 화두가 되고 있다. 이는 비용절감, 리드타임 단축, 서비스 수준 향상 등의 가치창출이 기업내부에서 뿐만 아니라 오히려 기업과 기업 간에서 더욱 큰 잠재력을 가지고 있음을 발견하게 되었기 때문이다. 본 연구에서는 공급사슬경영의 논리적인 Frame work을 입증하기 위하여 최적화시스템을 시뮬레이션 한다. 최적화생산시스템을 이용하는 시스템 하에서는 생산 시스템의 문제를 효과적인 흐름의 통제라는 관점에서 파악하며. 생산 현장에서 발생하는 많은 문제가 이들 흐름을 방해하는 요인에 의하여 발생하고 있다고 간주하기 때문이다 이와 같은 실험을 통하여 본 연구에서는 최적화생산시스템의 시뮬레이션 결과를 제시하고, 이로써 공급사슬경영의 유용성을 입증하는데 그 의의가 있다

• 산업공학
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• 제17권4호
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• pp.450-458
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• 2004

S-Distribution Center supplies parts to three plants of K-automobile manufacturing company. Since the three plants employ the JIT production system, it is important for S-Distribution Center to deliver small quantities of parts frequently and quickly on time. This paper presents a case study on the improvement of order-picking operation in S-Distribution Center. The study is focused on the reductions of move time and waiting time by redesigning the parts storage location, picking-order terminal location, retrieval policy, and equipment operation policy. The proposed operation system for S-Distribution Center is evaluated through a simple computation analysis and computer simulation. Furthermore, the reducible numbers of equipment and order pickers are investigated by performing a sensitivity analysis.

• 산업경영시스템학회지
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• 제20권43호
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• pp.1-16
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• 1997

This paper improves the autonomy for supplier's schedule and the flexibility of the final assembly line. The final assembly line is a single work station and each product taking different assembly time is considered. In the assembly schedule, the heuristic method based on the goal chasing method is used. Consequently, suppliers can independently determine their output rates and thus, change their workload pattern according to their needs and priorities. Moreover, this flexibility can help to avoid expensive final-assembly-line stoppages in case of sudden part supply disruptions. The sequencing method can be easily implemented into an existing just-in-time system. In addition, the mathematical model was formulated and the algorithm was explained through the flow chart. The numerical example was given and the efficiency of this method is shown through the analysis of computational results of that example.