• 한국군사과학기술학회지
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• 제25권5호
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• pp.530-538
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• 2022

Recently, the R&D of weapon systems has been strengthened in terms of economic cost management throughout the entire life cycle from performance. This study proposes the method for setting the optimal maintenance concept based on RAM-C in weapon system acquisition stage by calculating the operation & maintenance cost as well as reliability, availability, and maintainability. First, we design a simulation model for analysis of weapon system logistic supportability. In addition, information such as weapon system Part Breakdown Structure, operation & maintenance system, cost, and etc for simulation analysis, is applied. Based on the obtained simulation results, the optimal plan is selected among alternatives designed with various maintenance concepts through normalization and weight setting. It is expected to be of technical help in the application of RAM-C in the weapon system acquisition stage.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2002년도 추계 학술발표회 논문집
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• pp.147-151
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• 2002

Burn-in is a widely used method to eliminate initial failures. Preventive maintenance policy such as block replacement with minimal repair at failure is often used in field operation. In this paper burn-in and maintenance policy are taken into consideration at the same time. The cost of a minimal repair is assumed to be a non-decreasing function of its age. The problems of determining optimal burn-in times and optimal maintenance policy are considered.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권3호
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• pp.192-201
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• 2016

Purpose: In this paper, we propose the output model of the optimal inventory requirements of the Maintenance Float (M/F). Weapon systems were modernized and increased costs. Thus, the complexity increases with. Alternatives to achieve the goal of availability of weapon systems and to reduce life-cycle cost are required. Especially, securing spare parts is more effective than adding the amount of equipment or maintenance facilities to achieve the goal of availability and reduce life cycle costs. However, securing spare parts and repair costs are directly related, so exact requirements are needed. Methods: Three kinds of methods (Calculation method of applying the Poisson distribution, Calculation method of considering the number of CSP, and Calculation method of applying M&S program) that this paper proposed compare the influence of the availability and the amount of spare parts. Result: We calculate the cost of M/F when the operational availability is over than 80% and compare that result. The biggest cost was calculated from the Poisson distribution method. We found that requirements and unit price is the key factor that gives a significant effect. Conclusion: These three kinds of methods can be used as a basis for Maintenance Float calculation. Among them, the calculation method based on CSP is optimal replacement equipment requirements calculation method.

• 대한전기학회논문지:전력기술부문A
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• 제48권3호
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• pp.234-240
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• 1999

This paper presents a new approach for large-scale generator maintenance scheduling optimizations. The generator preventive maintenance scheduling problems are typical discrete dynamic n-dimensional vector optimization ones with several inequality constraints. The considered objective function to be minimized a subset of{{{{ { R}^{n } }}}} space is the variance (i.g., second-order momentum) of operating reserve margin to levelize risk or reliability during a year. By its nature of the objective function, the optimal solution can only be obtained by enumerating all combinatorial states of each variable, a task which leads to computational explosion in real-world maintenance scheduling problems. This paper proposes a new priority search mechanism based on each generator's discrete sensitivity value which was analytically developed in this study. Unlike the conventional capacity-based priority search, it can prevent the local optimal trap to some extents since it changes dynamically the search tree in each iteration. The proposed method have been applied to two test systems (i.g., one is a sample system with 10 generators and the other is a real-world lage scale power system with 280 generators), and the results anre compared with those of the conventional capacith-based search method and combinatorial optimization method to show the efficiency and effectiveness of the algorithm.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.169-176
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• 2009

This paper introduces 60 apply method at a railroad vehicle including basic technique of the 60. Basically rolling stock maintenance cost is high and life cycle is long. Therefore, the maintenance efficiency is the most important. Usually the length of the rolling stock life cycle is over 20years, the method of maintenance technique must be reformed periodically. So the key point of a inspection efficiency is to update the maintenance method regularly. The early days 60 method began from the thing to reduce a productions era. But after the year 2000, it took the place to the management reform technique of all business field. Finally optimal rolling stock maintenance method is introduced through the example.

• 한국군사과학기술학회지
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• 제3권1호
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• pp.26-37
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• 2000

This research paper deals with the problem of determining the optimal life time in terms of economical sense for a self-propelled artillery. Equivalent Annual Cost Method(EACM) is used to evaluate the optimal life time, based on the acquisition cost, and the operation and maintenance cost. It is assumed that the operation and maintenance cost includes the costs for spare parts, petroleum and ammunition for training. From the result of this study, the optimal life time for a self-propelled artillery is between 13.9 years and 16.1 years with 95% confidence interval.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.158-166
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• 2007

한국철도공사는 고속철도의 운행을 계기로 선진철도 정비방법의 습득과 더불어 기존차량에 대한 검수주기 및 방법에 대한 과학적이고 체계적인 시행을 위해 철도차량 RCM적용에 관한 연구를 시행 중이다. 그 동안 철도차량의 부품과 시스템에 대한 기술의 발전이 급속히 이루어지고 있는 것에 비해 정비방법의 발전은 상대적으로 느렸다고 할 수 있다. 이에 한국철도공사에서는 부품과 시스템의 기술발전에 앞서는 정비방법의 적용은 물론이고 차량의 기술적 발전을 리드할 수 있는 정비체계를 구축하고자 노력하고 있다. 고속차량인 KTX를 제외한 기존차량은 전동차, 전기기관차, 디젤기관차, 디젤동차, 객차, 화차 등으로 구분하여 운행되고 있다. 그 중 객차, 화차를 포함한 기존차종에 현행 시행되고 있는 검수 주기 및 방법을 분석하여 개선방향을 찾아 최적의 차량정비 주기 및 방법을 적용하고자 한다.

• 전기학회논문지P
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• 제58권4호
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• pp.410-415
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• 2009

With the implementation of electric power industry reform, the utilities are looking for effective ways to improve the economic efficiency. One area in particular, the equipment maintenance, is being scrutinized for reducing costs while keeping a reasonable level of the reliability in the overall system. Here the conventional RCM requires the tradeoff between the upfront maintenance costs and the potential costs of losing loads. In this paper we describe the issues related to applying so-called the "Reliability-centered Maintenance" (RCM) method in managing electric power distribution equipment. The RCM method is especially useful as it explicitly incorporates the cost-tradeoff of interest, i.e. the upfront maintenance costs and the potential interruption costs, in determining which equipment to be maintained and how often. In comparison, the "Time-based Maintenance" (TBM) method, the traditional method widely used, only takes the lifetime of equipment into consideration. In this paper, the modified Markov model for maintenance is developed. First, the existing Markov model for maintenance is explained and analyzed about transformer and circuit breaker, so on. Second, developed model is introduced and described. This model has two different points compared with existing model: TVFR and nonlinear customer interruption cost (CIC). That is, normal stage at the middle of bathtub curve has not CFR but the gradual increasing failure rate and the unit cost of CIC is increasing as the interruption time is increasing. The results of case studies represent the optimal maintenance interval to maintain the equipment with minimum costs. A numerical example is presented for illustration purposes.

• 한국구조물진단유지관리공학회 논문집
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• 제12권4호
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• pp.161-167
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• 2008

본 연구에서는 고등해석과 유전자 알고리즘을 이용한 트러스 구조물의 최적설계를 수행하였다. 본 연구에서 사용한 고등해석은 기하학적 비선형과 재료적 비선형을 동시에 고려한다. 최적화 알고리즘으로 마이크로 유전자 알고리즘을 사용하였다. 목적함수로 구조물의 중량을 사용하였으며, 제약조건식은 구조시스템의 하중-저항능력 및 변위 조건을 고려하였다. 제안된 방법에 의한 최적설계 결과를 기존의 연구결과와 비교하여 그 타당성을 증명하였다.

• 산업공학
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• 제13권4호
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• pp.680-687
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• 2000

The objectives of this research are to establish the operation scheduling and the preventive maintenance system in order to optimize the operation of mailing center. For the optimal operation scheduling of mailing process, the existing workflow of mailing process and that of required time are investigated prior to simulation modeling. The simulation experiments are conducted to increase the nextday delivery rate. The best alternative whose nextday delivery rate up to 100% is selected based the AHP(Analytic Hierarchy Process) method. The optimal work scheduling of all mailing centers are also presented. In addition, the CMMS(Computerized Maintenance Management System) for preventive maintenance is introduced for efficient operation of highly automated facilities of mailing center.