• 한국경영과학회지
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• 제37권1호
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• pp.19-28
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• 2012

We consider a multi-agent scheduling problem such that each agent tries to maximize the weighted number of just-in-time jobs. Two objectives are considered : the first is to find the optimal solution for one agent with constraints on the other agents' weight functions, and the second is to find the largest set of efficient schedules of which corresponding objective vectors are different for the case with identical weights. We show that when the number of agents is fixed, the single machine case with the first objective is NP-hard in the ordinary sense, and present the polynomial- time algorithm for the two-machine flow shop case with the second objective and identical weights.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 한국컴퓨터종합학술대회 논문집 Vol.33 No.1 (A)
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• pp.217-219
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• 2006

내장형 시스템에서 많이 채택되고 있는 자바 가상 머신의 성능을 향상시키기 위해 interpreter. just-in-time 컴파일러 (JITC), ahead-of-time 컴파일러 (AOTC) 세가지 방식을 모두 지원하는 자바 가상 머신을 설계하고 구현하였다. 특히 이런 환경을 지원하기 위한 효율적인 JITC와 시스템의 idle 시간에 JITC모듈을 활용하기 위한 client-AOTC의 설계와 구현에 대해 살펴보고 현재까지의 실험 결과를 보고한다.

• 산업경영시스템학회지
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• 제16권27호
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• pp.35-42
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• 1993

Just in time backup of the essential materials at industry and military is very important. Especially in case of military essential materials at wartime is so important as it controls victory and/or defeat. This paper presents the new approach for just in time suppling the essential materials at the beginning wartime - security step of materials, reservation priority and quantity requirement degree. In order to build the new approach, we introduced the concepts of cost and effect analysis for each essential item. First of all, the developed model will be useful to maximize combat sustaning power under constraint of budget.

• 대한산업공학회지
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• 제21권1호
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• pp.3-16
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• 1995

JIT manufacturing requires that materials and services should be done neither too early nor tardy. Therefore, related jobs have to be performed just-in-time. In this paper, we consider a problem of determining a schedule of jobs with a common due date. The objective is to minimize the squared deviation of complete times from the due date. An artificial neural network which is based on the mean field theory is proposed for the problem. Computational results obtained from computer simulations show that the network performs very well.

• 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.

• 산업경영시스템학회지
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• 제32권3호
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• pp.40-48
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• 2009

In this article, scheduling of a casting sequence is studied in a casting foundry which must deliver products according to the Just-in-time(JIT) production policy of a customer. When a foundry manufactures a variety of casts with an identical alloy simultaneously, it frequently faces the task of production scheduling. An optimal casting schedule should be emphasized in order to maximize the production rate and raw material efficiency under the constraints of limited resources; melting furnaces and operation time for a casting machine. To solve this practical problem-fulfilling the objectives of casting the assigned mixed orders for the highest raw material efficiency in a way specified by the customer's JIT schedule, we implement simple integer programming. A simulation to solve a real production problem in a typical casting plant proves that the proposed method provides a feasible solution with a high accuracy for a complex, multi-variable and multi-constraint optimization problem. Employing this simple methodology, a casting foundry having an automated casting machine can produce a mixed order of casts with a maximum furnace utilization within the due date, and provide them according to their customer's JIT inventory policy.

• 산업경영시스템학회지
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• 제25권1호
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• pp.42-48
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• 2002

This paper addresses the necessity of integration between buyer and suppliers for effective implementation of Just-In-Time purchasing in a multi-item environment. An integrated inventory model of facilitating multiple shipments in small lots is developed. Also, an iterative solution procedure is developed to simultaneously find the order(contract) interval for each item and number of shipments between buyer and suppliers. We show by example that when the integrated policy is adopted by both buyer and suppliers in a cooperative manner, both parties can benefit.

• Industrial Engineering and Management Systems
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• 제14권3호
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• pp.299-311
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• 2015

Nowadays, the distribution centres aim to reduce costs by reducing inventory and timely shipment. Cross docking is a logistics strategy in which products delivered to a distribution centre by inbound trucks are directly unloaded and transferred to outbound trucks with minimum warehouse storage. Moreover, on-time delivery in a distribution network becomes very crucial especially when several distribution centres and customers are involved. Therefore, an efficient truck scheduling is needed to synchronize the delivery throughout the network in order to satisfy all stake-holders. This paper presents a mathematical model of a mixed integer programming for door assignment and truck scheduling in a multiple inbound and outbound doors cross docking problem according to Just-In-Time concept. The objective is to find the schedule of transhipment operations to simultaneously minimize the total earliness and total tardiness of trucks. Then, a multi-objective differential evolution (MODE) is proposed with an encoding scheme and four decoding strategies, called ITSH, ITDD, OTSH and OTDD, to find a Pareto frontier for the multi-door cross docking problems. The performances of MODE are evaluated using 15 generated instances. The numerical experiments demonstrate that the proposed algorithm is capable of finding a set of diverse and high quality non-dominated solutions.

• 산업경영시스템학회지
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• 제18권36호
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• pp.219-232
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• 1995

Even though Just-In-Time Production System is introduced to industry in order to strengthen competition, applying this production system to field is hard and some problems are occurred. On this study, the algorithm which become smoothed production, one of the prerequisite condition for implementing Just-In-Time, are developed. On the other word. it is possible to become smoothed production based on keeping Lot Production System. The possibility of establishing more stable smoothed production scheduling are proved on this study by comparing with previous researches.

• 한국건설관리학회논문집
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• 제5권4호
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• pp.71-78
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• 2004

최근 우리나라의 건설 환경은 도심지 내 대형 건설공사가 증가하는 추세이며, 건설공사 관리 요소 중 기존 골조공사의 관리 중요성에 더하여 마감공사관리의 중요성이 부각되고 있다. 마감공사의 체계적인 관리를 위해서는 마감공사의 공정 중 자재 양중 측면, 공사기간 측면에서 많은 부분을 차지하고 있는 세대 내 가구공사의 관리체계 정립이 필수적이라 할 수 있다. 본 연구에서는 초고층 주거건축을 위한 마감공사 중 양중 측면에서 주 고려 대상이 되고 있는 가구공사의 관리체계를 정립하기 위하여, 적시생산(Just-In-Time)방식과 린건설(Lean Construction)의 개념을 도입하였다. 이를 바탕으로 가구공사의 프로세스를 분석하고 그에 따른 개선방안을 제시하였다. 이러한 분석과 개선방안의 제시는 마감공사의 원활한 흐름을 유도할 수 있으며, 또한 공사기간을 단축하고 공사비용을 절약함으로써 프로젝트의 성공에 기여할 수 있다.