• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 추계학술대회
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• pp.115-123
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• 2004

Replacement problems can be classed as either deterministic of stochastic. Deterministic problems are those in which the timing and the outcome of the replacement action are assumed to be known with certainty. Before proceeding with development of replacement models it is important to note that preventive replacement actions, that is, ones taken before equipment reaches a failed state, require two necessary conditions: (1) The total cost of the replacement must be greater after failure than before. (2) The failure rate of the equipment must be increasing. Equipment is subject to failure. On failure, one of two possible actions can be taken : repair or complete replacement of the failed equipment. In this paper, we proposed optimal overhaul, repair, replacement maintenance model with two-state.

• 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.

• 산업공학
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• 제12권1호
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• pp.114-120
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• 1999

A system consisting of two continuously and independently operating equipment subject to breakdown and repair, is considered. It is assumed that both equipment age only when in operation, and a group replacement policy is in effect, that is, both equipment are replaced simultaneously by new identical ones as soon as either of them reaches a specified replacement age. First, a system of partial differential equations based on enumerating the various probabilistic events, is derived. Then, solutions of such system of equations for a model considered in the steady-state are obtained. Finally, an economic analysis is performed to determine the optimal replacement ages of both equipment.

• 산업경영시스템학회지
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• 제10권16호
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• pp.75-80
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• 1987

This paper is deals with the preventive replacement for the equipment which fails only when the total amount of damage reaches a prespecified failure level. Most of replacement model use time as their decision variable, but it is not appropriate for the cases in which failures dependent on their cumulative damage levels. In this paper, a new type preventive replacement model is introduced in which an equipment is replaced before failure when the cumulative damage reaches a certain level or replaced on failure, whichever occures first. The optimal replacement damage levels which minimize total expected cost are obtained by the Dynamic programming Method when the number of use of the equipment is finite. A numerical example is also presented. The optimal preventive replacement policy when the equipment will be used for a finite time span is also discussed.

• 산업경영시스템학회지
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• 제17권30호
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• pp.51-57
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• 1994

This paper considers the problem of equipment replacement A equipment replacement problem is treated in a thchnological development environment. Our model assumes that the costs associated with the presently available thchnology and future technology is known, but the appearance times of future technology is uncertain. A cost model is presented, and method is suggested for finding the optimal operating time for replacement A numerical example is shown.

• 한국국방경영분석학회지
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• 제29권2호
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• pp.100-110
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• 2003

Equipment replacement policy may not be defined with certainty, because physical states of any technological system may not be determined with foresight. This paper presents Markov Decision Process(MDP) model for army equipment which is subject to the uncertainty of deterioration and ultimately to failure. The components of the MDP model is defined as follows: ⅰ) state is identified as the age of the equipment, ⅱ) actions are classified as 'keep' and 'replace', ⅲ) cost is defined as the expected cost per unit time associated with 'keep' and 'replace' actions, ⅳ) transition probability is derived from Weibull distribution. Using the MDP model, we can determine the optimal replacement policy for an army equipment replacement problem.

• 산업경영시스템학회지
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• 제19권39호
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• pp.229-234
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• 1996

When we analyze equipment replacement problem, we take the table of the duration period of tangible fixed asset on the corporation income tax law, and treat depreciation as simple allocation process for capital recovery. In this problem, there are some papers considering the concepts of economic depreciation. Those are not perfect model from a economical point of view. Therefore, we deal with equipment replacement problem considering the engineering valuation as well as the economic concept in the evaluation of asset.

• 경영과학
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• 제8권1호
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• pp.41-50
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• 1991

Within the current construction industry, constractor equipment management practices lack structure and often are not addressed through an economic analysis and evaluation process. This paper explores two areas...cost of capital and inflation...with the intention of providing insight for a more structured and economic based approach to contractor equipment replacement practices rather than by the traditional "rule of thumb".umb".uot;.

• 한국ITS학회 논문지
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• 제6권3호
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• pp.174-182
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• 2007

현재 국내 ITS는 현장장비 유지관리에 대한 연구 및 고장관련 DB가 부족하여 예비부품수 및 교체시기 산정에 대한 규정이 없는 실정이다. 이에 본 연구는 실제 고장이력자료를 갖고 신뢰성 분석을 실시하여 단거리전용통신(DSRC)방식 노변기지국(RSE)의 예비부품수 및 교체시기를 산정하였다. 전체 수집기간동안의 고장자료는 욕조곡선의 형상을 나타내어 우발고장기간의 자료로 신뢰성 분석을 실시하였으나 고장 수명 분포 중 적합되는 분포가 없었으며, 이러한 사실은 본 연구대상 노변기지국(RSE)의 경우 통계적 모형에 의한 예방 정비가 어려움을 의미한다. 따라서, 본 연구는 실증적인 방법으로 하자보수기간 $1{\sim}2$년 동안의 수리비용 및 고장빈도 이력자료를 활용하여 노변기지국(RSE)의 교체여부를 결정하는 방법 및 필요 예비부품수를 산정하는 방법을 제안하였다. 향후에는 노변기지국(RSE) 외에 다른 ITS 장비에 대한 신뢰성 분석이 필요하다.

• 산업공학
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• 제16권1호
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• pp.27-33
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• 2003

The maintenance cost in K Steelworks has been continuously increased in proportion to the production cost. However, there seems to be a possibility of reducing cost through the optimization of maintenance actions. The failure types of the equipment in steelworks ate various with different failure cost. Thus the failure rate and cost of each type of failures should be considered simultaneously when the optimum maintenance period is to be determined. It is considered that the equipment undergoes periodic replacement and a specified number of incomplete preventive maintenance actions are performed during a replacement period. Assuming that the time to failure follows a Weibull distribution, the parameters of the failure rate are estimated using the maximum likelihood estimation. The optimal replacement period is determined to minimize the average cost per unit time. As the result of analysis it is suggested that the existing maintenance period for a hot-rolling equipment can be extended significantly.