• 한국산학기술학회논문지
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• 제14권10호
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• pp.4893-4901
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• 2013

방위 산업에서는 무기체계라 말하는 장비가 목표 수명동안 지속적으로 사용 할 수 있도록 설계에서부터 정비까지 많은 분야에 걸쳐 연구가 이루어지고 있다. 하지만, 장비를 수리하는데 필요한 수리부속이 저장 및 불출되는 군 보급 시설의 운용 관리는 현실적 연구가 부족한 상황이다. 그래서 이 글에서는 군 보급시설의 효율적인 운용 관리를 위하여 저비용 고효율을 얻을 수 있는 수리부속 배치에 대한 연구를 제시한다. 먼저, 수리부속을 MTBF(Mean Time Between Failure) 기준 하에 A/B/C 그룹으로 나누어 기본적인 배치 대안들을 정의한다. 이렇게 정의된 대안들은 시뮬레이션과 작업 자세 평가 도구인 RULA(Rapid Upper Limb Assessment)를 통해 대안 선정에 필요한 평가 속성인 작업 시간과 자세 위험도를 도출하고, 이를 엔트로피 척도를 통해 대안 결정을 한다. 본 연구는 작업 시간과 자세 위험도를 최소화 하여 군 보급 시설 내 효율적인 수리부속 배치 방법을 제시하였다. 이는 군 보급시설의 시스템 및 인간공학적 접근을 함께 고려한 점에서 앞으로의 연구에 새로운 방향을 제시하였다 할 수 있다.

• 품질경영학회지
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• 제18권2호
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• pp.9-17
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• 1990

This paper deals with a FOQ( ; fixed-order quantity) model for spare-part inventory control. In a spare-part inventory problem, stock depletion arises not from external market demand but from internal demand resulting from failures of parts in use. The problem differs from the classical inventory problem in that the demand for a failed part never arises more during stockout period, since the unit remains inoperative when stockout occurs until the failed part is replaced by new one. In the problem under consideration, n identical units are operating simultaneously and failed one is replaced immediately by new one if on-hand spares remain. In order to replenish spares, an order with quantity Q is placed whenever the number of on-hand spares falls to levels. The average annual cost of operating the spare-part inventory system is derived under the assumption that both lifetime of a part and replenishment lead-time distributions are exponential.

• 대한산업공학회지
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• 제36권3호
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• pp.164-175
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• 2010

In this study, we developed a genetic algorithm to find a near optimal solution of concurrent spare parts selection for the operational time period with limited information of weapon systems purchased from overseas. Through the analysis of time profiles related with system operations, we first define the optimization goal which maintains the expected system operating rate under the budget restrictions, and the number of failures and the lead time for each spare part are used to calculate the estimated total down time of the system. The genetic algorithm for CSP selection shows that the objective function minimizes the estimated total down time of systems with satisfying the restrictions. The method provided by this study can be applied to the generalized model of CSP selection for the systems purchased from overseas without provision of their full structure and adequate information.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1993년도 춘계공동학술대회 발표논문 및 초록집; 계명대학교, 대구; 30 Apr.-1 May 1993
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• pp.124-124
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• 1993

• Journal of Advanced Marine Engineering and Technology
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• 제37권2호
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• pp.178-182
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• 2013

채굴이나 유사한 산업에서 버킷 회전형 소형 굴삭기가 협소한 공간 작업에 흔히 사용된다. 이러한 소형 굴삭기가 많이 개발이 되고 있지만 버킷회전부의 응력 해석 연구가 없었다. 본 연구에서 유한요소법과 Spare solver를 이용하여 소형 굴삭기의 버킷 회전부와 그 인접부의 응력 해석을 다양한 위상에서 수행하였다. 결론적으로 회전부의 연결부분에서 응력집중으로 인해 다른 부분의 평균 응력 1MPa보다 조금 높은 응력을 확인하였다. 특히 상대운동이 있는 버킷 핀과 회전 피니언 기어에서 각각 7.7MPa과 40MPa 응력을 보였다.

• 한국국방경영분석학회지
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• 제1권1호
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• pp.131-135
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• 1975

One of the pending issues of the Ministry of Defense is the efficient management of space parts for the weapon systems. It has been known that more than 000 million dollars are needed for spare parts for the weapon systems annually. Though the problem demands a serious consideration, there has not been any systematic study on the problem as far as the author knows. One way to approach the problem is through an investigation of the system reliability under constraints. A measure of how well a system performs or meets its design objectives is provided by the concept of system reliability. If successful operation is desired for a specified period of time, reliability is defined as the probability that the system will perform satisfactorily for the required time period. This interpretation of reliability is normally applied to devices which are subject to random failures such as electrical or mechanical systems. It has been found necessary to express system reliability in terms of the reliability of the components or subsystems which comprise the system. The major subsystems of an aircraft, for example, include the electronics, powerplant, airframe and armament subsystems. Therefore, the optimal spare part kit can be found by maximizing the system reliability subject to cost or other constraints.

• 산업경영시스템학회지
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• 제33권3호
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• pp.199-207
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• 2010

In this paper considered is the provisioning quantity determination problem of consumable concurrent spare parts (CSP) of a new equipment system to minimize the procurement cost under the operational availability constraint. When a part fails, repair of the failed part is impossible and the part is replaced and cannibalization is allowed. The failure of a part is assumed to follow a Poisson process and the operational availability in CSP is defined. The solution procedure consists of two parts. Firstly, a heuristic algorithm is developed under the assumption that the failure rate is constant during the CSP period. Secondly, proposed is a simulation search procedure which improves the heuristic solution to the near optimal solution in a reasonable amount of time. An illustrative example is shown to explain the solution procedure.

• 대한조선학회논문집
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• 제46권2호
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• pp.171-178
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• 2009

In this paper, RFID (Radio Frequency Identification) based management system is introduced to control effectively logistic supply items and machinery spare parts in a ship. To apply an RFID system under very harsh environment in a ship which is a steel-structured small area with lots of compartment, we measured reading distances and angles in open space, in an steel compartment, and an real ship separately in order to investigate the reliability between various tags and RFID.

• 산업경영시스템학회지
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• 제45권4호
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• pp.187-198
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• 2022

This paper addresses the maintenance optimization problem in multi-component systems in which parts are connected in series, carrying out several missions interspersed with scheduled finite breaks. Due to limited time or resources, maintenance actions can be only carried out on a limited set of components. The decision maker then has to decide which components to maintain to ensure a pre-specified performance level during next mission. Most of the existing models in the literature usually assume only one system and enough spare parts. However, there are situations in which maintenance is required for multiple systems of the same type. To overcome this restrictive assumption, this study optimizes the maintenance problem considering the lack of repair parts and cannibalism for many identical systems. This study presents two optimization models with different objectives to solve the problem and analyzes the results so that the decision maker can decide. The results of this study are expected to be used for the maintenance of multiple systems of the same type, such as swarm drones.

• Industrial Engineering and Management Systems
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• 제16권1호
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• pp.52-63
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• 2017

The inventory level of concurrent spare parts (CSP) has a significant impact on the availability of a weapon system. A failure rate function might be of particular importance in deciding the CSP inventory level. We developed a CSP optimization model which provides a compromise between purchase costs and shortage costs on the basis of the Weibull and the exponential failure rate functions, assuming that a failure occurs according to the (non-) homogeneous Poisson process. Computational experiments using the data obtained from the Korean Navy identified that, throughout the initial provisioning period, the optimization model using the exponential failure rate tended to overestimate the optimal CSP level, leading to higher purchase costs than the one using the Weibull failure rate. A Pareto optimality was conducted to find an optimal combination of these two failure rate functions as input parameters to the model, and this provides a practical solution for logistics managers.