• Title/Summary/Keyword: Cost of Failure Cost

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Evaluation Methodology of System Interruption Cost Taking into Consideration Failure Rate of Distribution Facilities (배전기자재별 고장확률을 고려한 배편계통 수용가 정전비용 산출 기법)

  • Choe, Sang-Bong;Kim, Dae-Gyeong;Jeong, Seong-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.5
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    • pp.232-237
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    • 2002
  • It is increased for methodology to evaluate distribution power system interruption cost in power supply zones under competitive electricity market. This paper presents algorithms to evaluate system interruption cost in distribution power supply zones taking into consideration failure rate of distribution facilities and composite customer interruption cost. In this paper, it is introduced for weighting factor for each customer failure duration and failure rate of distribution facilities to evaluate reasonable system interruption cost in distribution power supply area. Also, this Paper estimates evaluation results of system interruption cost using a sample model system. Finally, evaluation results of system interruption cost based on failure rate of distribution facilities and composite customer interruption cost are shown in detail.

A Study on the Optimal Equipment Selection of Series Systems using Life Cycle Cost and Failure Cost (Failure Cost와 Life Cycle Cost를 고려한 연속시스템에 대한 최적 장치 선택에 관한 연구)

  • Jin Sang-Hwa;Kim Yong-Ha;Song Hee-Oeul;Yeo Yeong-Koo;Kim In-Won
    • Journal of the Korean Society of Safety
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    • v.19 no.4 s.68
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    • pp.55-59
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    • 2004
  • In this study, the required life cycle cost is evaluated in consideration of the equipment's availability during its lift cycle. In order to meet the maximum availability required by the process, the failure cost and life cycle cost is assessed The optimal equipment selection method is presented according to the analysis of the failure cost and life cycle cost. For the systems in which equipments are connected serially, the optimal equipments are selected by minimizing the life cycle cost and satisfying the required system availability goal. In addition, the selection methods and lift cycle cost are analyzed according to the cost variation of the equipment. By using the life cycle evaluation procedure, the failure cost and maintenance cost needed during the life cycle of the equipment can be presented.

Error Forecasting & Optimal Stopping Rule under Decreasing Failure Rate (감소(減少)하는 고장률(故障率)하에서 오류예측 및 테스트 시간(時間)의 최적화(最適化)에 관한 연구(硏究))

  • Choe, Myeong-Ho;Yun, Deok-Gyun
    • Journal of Korean Society for Quality Management
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    • v.17 no.2
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    • pp.17-26
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    • 1989
  • This paper is concerned with forecasting the existing number of errors in the computer software and optimizing the stopping time of the software test based upon the forecasted number of errors. The most commonly used models have assessed software reliability under the assumption that the software failure late is proportional to the current fault content of the software but invariant to time since software faults are independents of others and equally likely to cause a failure during testing. In practice, it has been observed that in many situations, the failure rate decrease. Hence, this paper proposes a mathematical model to describe testing situations where the failure rate of software limearly decreases proportional to testing time. The least square method is used to estimate parameters of the mathematical model. A cost model to optimize the software testing time is also proposed. In this cost mode two cost factors are considered. The first cost is to test execution cost directly proportional to test time and the second cost is the failure cost incurred after delivery of the software to user. The failure cost is assumed to be proportional to the number of errors remained in the software at the test stopping time. The optimal stopping time is determined to minimize the total cost, which is the sum of test execution cast and the failure cost. A numerical example is solved to illustrate the proposed procedure.

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Determination of Machining Speed Considering Failure Cost (절삭 가공에서의 불량 발생 비용을 고려한 가공속도 결정에 관한 연구)

  • Park, Chan-Woong
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.33 no.4
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    • pp.153-158
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    • 2010
  • This study presents a single machine scheduling algorithm to minimize total cost(lateness cost, earliness cost and failure cost) by controlling machining speed. Generally, production scheduling uses the information of process planning and machining speed is not changed at production scheduling. And failure cost is not consider for scheduling algorithm. Therefore, the purpose of this study is to consider the change of machining speed for efficient production scheduling. And performance criteria for algorithm considers total cost. Especially, failure cost of product by increasing machining speed is considered.

COST TABLE을 이용한 품질코스트 계산에 관한 연구

  • Gang, Gyeong-Sik;Kim, Tae-Ho;Hwang, Gyeong-Su
    • Journal of Korean Society for Quality Management
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    • v.21 no.2
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    • pp.35-47
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    • 1993
  • This study was performed to obtain the internal failure cost in the failure and rework using cost table. The manufacturing cost is different according to each production process. Thierefore, it is difficult to calculate of the manufacturing cost. Using the cost table internal failure cost can be calculated easily in each process.

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Warranty cost anlaysis for multi-component systems with imperfect repair

  • Park, Minjae
    • International Journal of Reliability and Applications
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    • v.15 no.1
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    • pp.51-64
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    • 2014
  • This paper develops a warranty cost model for complex systems with imperfect repair within a warranty period by addressing a practical case that the first inter-failure interval is longer than any other inter-failure intervals. The product is in its best condition before the first failure if repair is imperfect. After the imperfect repair, other inter-failure intervals which are explained by renewal processes, are stochastically smaller than the first inter-failure interval. Based on this idea, we suggest the failure-interval-failure-criterion model. In this model, we consider two random variables, X and Y where X represents failure intervals and Y represents failure criterion. We also obtain the distribution of the number of failures and conduct the warranty cost analysis. We investigate different types of warranty cost models, reliabilities and other measures for various systems including series-parallel configurations. Several numerical examples are discussed to demonstrate the applicability of the methodologies derived in the paper.

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Evaluation of the Interruption Cost of Distribution Power Systems Considering the Failure Source and the Composite Customer Interruption Cost

  • Park, Sang-Bong;Nam, Kee-Young;Kim, Dae-Kyeong;Jeong, Seong-Hwan
    • KIEE International Transactions on Power Engineering
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    • v.3A no.3
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    • pp.124-129
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    • 2003
  • As the power industry moves towards open competition, there has been a call for methodology to evaluate power system reliability by using composite interruption cost. This paper presents algorithms to evaluate the interruption cost of distribution power systems by taking into consideration the failure source and the composite customer interruption cost. From the consumer's standpoint, the composite customer interruption cost is considered as the most valuable index to estimate the reliability of a power distribution system. This paper presents new algorithms that take into account the load by customer type and failure probability by distribution facilities while calculating the amount of unserved energy by customer type. Finally, evaluation results of unserved energy and system interruption cost based on composite customer interruption cost are shown in detail.

The ($\textsc{k}, t_p$) Replacement Policy for the System subject to Two Types of Failure

  • Lee, Seong-Yoon
    • Journal of the military operations research society of Korea
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    • v.25 no.2
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    • pp.144-157
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    • 1999
  • In this paper, we consider a new preventive replacement policy for the system which deteriorates while it is in operation with an increasing failure rate. The system is subject to two types of failure. A type 1 failure is repairable while a type 2 failure is not repairable. In the new policy, a system is replaced at the age of $t_p$ or at the instant the$\textsc{k}^{th}$ type 1 failure occurs, whichever comes first. However, if a type 2 failure occurs before a preventive replacement is performed, a failure replacement should be made. We assume that a type 1 failure can be rectified with a minimal repair. We also assume that a replacement takes a non-negligible amount of time while a minimal repair takes a negligible amount of time. Under a cost structure which includes a preventive replacement cost, a failure replacement cost and a minimal repair cost, we develop a model to find the optimal ($\textsc{k},t_p$) policy which minimizes the expected cost per unit time in the long run while satisfying a system availability constraint.

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Determining the Optimum Maintenance Period of the Steel Making Equipment Having Multiple Failure Types (다수의 고장유형을 갖는 제철설비의 최적 정비주기 산출)

  • Song, Hong-Jun;Jun, Chi-Hyuck
    • IE interfaces
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    • v.16 no.1
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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.

The Correlations among the Categorized Quality Cost Factors on Small & Medium-sized Enterprises (국내 중소 제조기업의 품질비용 행태에 관한 실증 연구)

  • Koo, Il-Seob;Lee, Sang-Choon;Jang, Kwang-Soon;Kim, Yong-Bum
    • Journal of the Korea Safety Management & Science
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    • v.13 no.2
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    • pp.185-193
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    • 2011
  • The successful and sustainable growth of SMEs depends on their ability of strengthen their competitiveness in quality and cost and service more than anything else as a fundamental of operation. Among these key competitive factors of SMEs, quality is the most critical factor in manufacturing business fields. There are many different ways to improve the quality performance but it needs proper management decision to choose the best way what can maximize outputs with minimum inputs. And it needs effective measurement methods and some indicators to analysis the quality performance properly. The quality cost is one of the simplest key indicators to measure the quality performance and the effectiveness of quality related management decisions. In this study, through survey on local SMEs, we found that their average annual quality cost ratio versus turnover - total amount of annual quality cost divided by annual turnover - is around 3.69% excluded some SME's performances what have different quality control measures with others. And we found some results what corresponded with the early studies on the correlations between those categorized quality costs factors and some discrepancies between some of the literature model and the early case study results as follows. There were negative correlations between the Prevention costs and the External failure costs, and the Appraisal costs and the External failure costs, and there was positive correlation between the Appraisal costs and Internal failure costs same as early studies. But, we couldn't found any strong negative correlations between the Cost of control - Prevention costs & Appraisal costs - and the Cost of Failure of control - Internal & External failure costs -.