• 산업경영시스템학회지
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• 제29권3호
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• pp.135-142
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• 2006

Engineers are always concerned with life cycle costs for making important economic decisions through engineering action like reliability of products. Decisions during the reliability growth development of products involve trade-offs between invested costs and its returns. In order to find minimal LCC containing the reliability improvement cost, production cost, repair and replacement costs, and holding cost of spare parts for failure items we suggest in this paper relationship between development cost and sustaining cost in values of growth parameter $\beta$ of AMSAA model. This model is applied to the reliability growth program based on AMSAA model during R&D phase, the warranty activities of items and the block replacement policy for maintenance of items in avionic equipment.

• 한국건설관리학회논문집
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• 제2권2호
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• pp.59-67
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• 2001

본 연구는 사례연구를 통해서 강박스교와 PSC박스교의 생애주기비용(LCC)을 분석하여 경제성을 평가하는데 목적이 있다. 본 연구에서는 유지관리비를 산출하기 위해 보수 및 교체주기에 대한 설문조사를 실시하였으며, 교량 형식별 LCC 분석 및 비교에는 현재가치 법을 이용하였다. 본 연구의 수행 결과를 요약하면 다음과 같다. (1) 사례 연구를 통해 강박스교와 PSC박스교의 LCC 분석모델을 제시하였다. (2) 설문조사를 실시하여 강박스교와 PSC박스교 부속물의 보수 및 교체주기를 산정하였다. (3) LCC 사례 연구 결과, PSC박스교가 강박스교보다 경제적인 것으로 분석 되었다.

• 한국군사과학기술학회지
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• 제4권1호
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• pp.170-176
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• 2001

An optimization problem to obtain the optimal replacement interval considering the salvage values is studied. The system is minimally repaired at failure and is replaced by new one at age T(periodic replacement policy with minimal repair of Barlow and Hunter〔2〕). Our model assumes that the time horizon associated with the number of replacements is random The total expected cost considering the salvage values with random time horizon is obtained and the optimal replacement interval minimizing the cost is found by numerical methods. Comparisons between non-considered salvage values and this case are made by a numerical example.

• 산업경영시스템학회지
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• 제18권33호
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• pp.87-92
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• 1995

This paper proposes age replacement policy in stepdown warranty policy. The replacement policy is considered in case of minimally repairable items. And renewal theory is used in analyzing warranty costs. The expected cost per unit time is presented in stepdown warranty policy, free replacement, prorata and hybrid policy. In this article it is assumed that item is replaced at the age of T but the any failure is minimally repaired before the age T. At this point the expected cost per unit time is shown in customer's view point. And numerical example is explored in weibull time-to-failure distribution.

• 품질경영학회지
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• 제21권2호
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• pp.109-120
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• 1993

Most systems are composed of components which have different failure chracteristics. Since the failure characteristics of components is different, it is rational and reasonable to establish a maintenance model to be considered repair and replacement policies which are proper to failure characteristics of these components. This paper proposes the age replacement time for a system composed of components which have different failure characteristics. In this model, it is assumed that a system is composed of a critical failure component, a major failure component, minor failure component. If any failure occurs to critical component before its age replacement time, the system should be replaced. If any failure does not occur until its age replacement time, preventive replacement should be performed at age replacement time T. Major component is minimal repaired if any failure occurs during operation. Minor component should be replaced as soon as failure is found. This paper determines the optimal replacement time of the system which minimize, total maintenance cost and initial stock Quantity of minor component within this optimal replacement time. Numerical example illustrates these results.

• Korean Journal of Hydrosciences
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• 제8권
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• pp.31-40
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• 1997

Flow carrying capacity of water distribution systems is getting reduced by deterioration of pipes in the systems. The objective of this paper is to present a managerial decision-making model for the rehabilitation of water distribution systems with a mininum cost. The decisions made by the model also satisfy the requirements for discharge and pressure at demanding nodes in the systems. Replacement cost, pipe break repair cost, and pumping cost are considered in the economic evaluation of the decision along with the break rate and the interest rate to determine the optimal replacement time for each pipe. Then, the hydraulic integrity of the water distribution system is checked for the decision by a pipe network simulator, KYPIPE, if discharge and pressure requirements are satisfied. In case the system does not satisfy the hydraulic requirements, the decision made for the optimal replacement time is revised until the requirments are satisfied. The model is well applied to an existing water distribution system, the Seoul Metropolitan Water Supply System (1st Phase). The results show that the decisions for the replacement time determined by the economic analysis are accepted as optimal and hydraulic integrity of the system is in good condition.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2005년도 학술발표대회 논문집
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• pp.115-120
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• 2005

This paper introduces models for preventive maintenance policies and considers periodic preventive maintenance policy with minimal repair when the failure of system occurs. It is assumed that minimal repairs do not change the failure rate of the system. The failure rate under prevention maintenance received an effect by a previously prevention maintenance and the slope of failure rate increases the model where it considered. Also the start point of failure rate under prevention maintenance considers the degradation of system and that it increases quotient, it assumed. Per unit time it bought an expectation cost from under this prevention maintenance policy. We obtain the optimal period time and the number for the periodic preventive maintenance by using Nakagawa's Algorithm, which minimizes the expected cost rate per unit time. Finally, it suppose that the failure time of a system has a Weibull distribution as an example and we obtain an expected cost rate per unit time the optimal period time and the number when cost of replacement and cost of minimal repair change.

• 농촌지도와개발
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• 제25권3호
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• pp.149-160
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• 2018

This study aimed to analyze the replacement investment of the diesel fuel system with the pallet fuel system in the Korean farming sector. Equivalent annual annuity approach was used to resolve a discrepancy of useful life in capital goods and to facilitate investment analyses in an independent perspective. Data was obtained from previous studies on economic analysis of greenhouse tomato, paprika and cucumber. Results showed that the replacement with the pallet fuel system was acceptable irrespective of the remaining period of useful life for the diesel fuel system. In addition, sensitivity analysis with government support level, repair cost, and light and heat energy cost show ed robustness in the possibility of replacement with the pallet fuel system while the speed of replacement was accelerated with an increase in the amount of diesel fuel used and price of diesel fuel, and a decrease in price of the pallet fuel. The result implied that the replacement investment rather than a new investment was appropriate for existing greenhouse farmers and the pallet fuel system was acceptable to replace existing diesel fuel system in producing greenhouse tomato, paprika and cucumber.

• 품질경영학회지
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• 제42권1호
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• pp.1-14
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• 2014

Purpose: In this paper, the minimal repair-replacement warranty policy is used to carry out a warranty cost analysis with warranty servicing times and failure times that are statistically correlated to bivariate distributions. Methods: Based on the developed approach by Park and Pham (2012a), we investigate the property of the Freund's bivariate exponential distribution and obtain the number of warranty services using the field data to conduct the warranty cost analysis. Results: Maximum likelihood estimates are presented to estimate the parameters and the warranty model is investigated using a Freund's bivariate exponential distribution. A numerical example is discussed to deal with the applicability of the developed approach in the paper. Conclusion: A novel approach of analyzing the warranty cost is proposed for a product in which failure times and warranty servicing times are used simultaneously to investigate the eligibility of a warranty claim.

• 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.