• Journal of the Korean Data and Information Science Society
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• v.25 no.4
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• pp.791-798
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• 2014

Wu and Clements-Croome (2005) suggest the preventive maintenance (PM) model with random maintenance quality. They assume that each PM resets the failure rate to zero and the rate of increases of the failure rate gets higher after each additional PM. However a system may not be restored to as good as new immediately after the completion of PM. Thus, this paper modifies the Wu and Clements-Croome's PM model and then the optimal PM policy is suggested. To determine the optimal PM policy, we utilize the expected cost rate per unit time for our model. That is, we obtain the optimal number and the optimal period by minimizing the expected cost rate per unit time. The numerical examples are presented for illustrative purpose.

• Communications for Statistical Applications and Methods
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• v.15 no.1
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• pp.77-86
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• 2008

This paper develops the optimal periodic preventive maintenance policy following the expiration of non-renewing warranty. We assume that Wu and Clements-Croome's (2005) periodic PM model with random maintenance quality is utilized to maintain the system after the non-renewing warranty is expired. Given the cost structure to the user during the cycle of the product, we drive the expressions for the expected cost rate per unit time. Also, we obtain the optimal number and the optimal period by minimizing the expected cost rate per unit time. The numerical examples are presented for illustrative purpose.

• Proceedings of the Korean Reliability Society Conference
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• 2006.05a
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• pp.76-81
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• 2006

• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.999-1007
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• 2009

This paper considers the optimal periodic preventive maintenance (PM) policy following the expiration of free-repair warranty. We assume that two periodic PM models with random maintenance quality which were proposed by Wu and Clements-Croome (2005) and Jung (2006b), respectively. Given the cost structure to the user during the cycle of the product, we derive the expressions for the expected cost rate per unit time. Also, we obtain the optimal PM number and the optimal PM period by minimizing the expected cost rate per unit time. The numerical examples are presented for illustrative purpose.

• Communications for Statistical Applications and Methods
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• v.17 no.6
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• pp.865-877
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• 2010

This paper considers the periodic preventive maintenance model for a repairable system following warranty expiration. We consider three types of warranty policies: free repair warranty, pro-rata repair warranty, and combination repair warranty. Under these preventive maintenance models, we derive the expressions for the expected cycle length, the total expected cost, and the expected cost rate per unit time. In addition, we explain the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for a Weibull distribution case.

• Proceedings of the Safety Management and Science Conference
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• 1999.11a
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• pp.123-131
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• 1999

최근에는 수요자 요구의 다양화, 전문인력의 부족, 고임금화, 열악한 작업장에서의 작업기피 현상 등의 영향으로 인해 생산 및 물류의 자동화가 활발히 추진되고 있다. 생산 및 물류시스템의 자동화가 진전됨에 따라 전체 시스템의 물류합리화에 중요한 역할을 담당하는 자동창고 시스템에 대한 설비관리 체계 구축이 필요하게 되었고, 그 일환으로 본 연구에서는 자동창고에 대한 예방보전 및 원인진단을 지원하는 자동창고의 예방보전 및 진단시스템을 개발하였다. 특히 자동창고의 이상을 진단하는데 과거의 트러블내용을 사례로 등록시키고, 전문가가 문제해결에 사용한 경험데이타, 즉 조사항목, 조사결과 및 대처내용을 진단용 사례기반 추론베이스로 구축하여 활용하는 사례기반추론(Case Based Reasoning)방법으로 접근시켰다. 또한 자동창고시스템의 예방보전, 사후보전, 이력관리 기능을 수행할 수 있는 운영소프트웨어를 개발하였다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.171-178
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• 1997

본 연구는 셀루라 제조방식을 갖고 있는 대기업에서의 예방보전에 관한 연구이다. 특히 24 시간운영하는 생산시스템을 갖고있으며, 보전요원이 충분한 업종이나 기업을 연구대상으로 하였다. 새로운 예방보전 절차를 제시하고 하나의 셀을 모델링하였다. 이 모델을 대상으로 시뮬레이션기법을 사용하여 기존에 절차와 비교분석하였다.

• Journal of the Korean Data and Information Science Society
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• v.22 no.4
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• pp.775-784
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• 2011

In this paper, we consider the periodic preventive maintenance model for repairable system following the expiration of non-renewing free replacement-repair warranty (NFRRW). Under this preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for Weibull distribution case.

• Journal of the Korean Data and Information Science Society
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• v.24 no.4
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• pp.773-781
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• 2013

Recently, an extended warranty of the system following the expiration of the basic warranty is becoming increasingly popular to the user. In this respect, we suggest a preventive maintenance model following the expiration of extended warranty with minimal repair warranty from the user's point of view in this paper. Under basic warranty and extended warranty, the failed system is minimally repaired by the manufacturer at no cost to the user. For the preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the numerical examples are presented to illustrate the purpose when the failure time of the system has a Weibull distribution.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1997.03a
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• pp.223-234
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• 1997

본 연구에서는 PC를 기반으로 하는 설비 보전정보 시스템의 개발시 구현되어야 할 기능들을 정리한다. 보전정보 시스템을 설비자료관리. 예방보전계획, 작업지시 시스템, 보전 자재관리의 네부분으로 나누어 각 부분에서 필요한 기능들을 정리하고, 보전업무의 수행 절차를 정립한다. 중소기업을 위한 PC기반 보전정보 시스템의 개념도가 제시된다.