• Title/Summary/Keyword: Optimal operating policy

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Informative Approach for Optimal Control Policy of Man-Machine System (인간-기계시스템의 최적관리를 위한 정보이론적 접근)

  • 이태희
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.19 no.37
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    • pp.63-70
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    • 1996
  • This paper presents a model which may be used in optimal control of the Man-Machine systems in the aspect of information transmission. For this, we divided information into human parts and machine parts, and consider minimum error principle as a machine operating logic. Furthermore, we take the maximum information principle as a human information operating logic. This can be done in considering the Fisher Information and its transformed type, information inequality.

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A genetic algorithm for determining the optimal operating policies in an integrated- automated manufacturing system (통합자동생산시스템에서 최적운영방안 결정을 위한 유전자 알고리즘의 개발)

  • 임준목
    • Journal of Korea Society of Industrial Information Systems
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    • v.4 no.2
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    • pp.62-72
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    • 1999
  • We consider a Direct Input Output Manufacturing System(DIOMS) which has a munber of machine centers placed along a built-in Automated Storage/Retrieval System(AS/RS). The Storage/Retrieval(S/R) machine handles parts placed on pallets for the machine centers located at either one or both sides of the AS/RS. This paper deals with the operational aspect of DIOMS and determines the optimal operating policy by combining computer simulation and genetic algorithm. The operational problem includes: input sequencing control, dispatching rule of the S/R machine, machine center-based part type selection rule and storage assignment policy. For each operating policy, several different policies are considered based on the known research results. In this paper, using the computer simulation and genetic algorithm we suggest a method which gives the optimal configuration of operating policies within reasonable computation time.

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Optimal Preventive Maintenance Policy Based on Aperiodic Model

  • Kim, Hee-Soo;Yum, Joon-Keun;Park, Dong-Ho
    • Proceedings of the Korean Reliability Society Conference
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    • 2000.11a
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    • pp.335-342
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    • 2000
  • Preventive maintenance(PM) is an action taken on a repairable system while it is still operating, which needs to be carried out in order to keep the system at the desired level of successful operation. The PM improves the reliability of the system by predicting the possible failures and thereby preventing such failures from its occurrence. In this paper, we develop the optimal preventive maintenance policies based on the aperiodic PM model. We investigate an aperiodic preventive maintenance policy and propose several optimal PM policies which minimize the expected cost over an infinite time span. Park, Jung and Yum(2000) determine the optimal period and the optimal number of PMs based on Canfield's(1986) periodic model. Our techniques to derive the optimal preventive maintenance policies based on our aperiodic PM model is similar to those in Park, Jung and Yum(2000), which can be considered as the special case of our results.

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Incorporating Climate Change Scenarios into Water Resources Management (기후 변화를 고려한 수자원 관리 기법)

  • Kim, Yeong-O
    • Journal of Korea Water Resources Association
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    • v.31 no.4
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    • pp.407-413
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    • 1998
  • This study reviewed the recent studies for the climate change impact on water resource systems and applied one of the techniques to a real reservoir system - the Skagit hydropower system in U.S.A. The technique assumed that the climate change results in ±5% change in monthly average and/or standard deviation of the observed inflows for the Skagit system. For each case of the altered average and standard deviation, an optimal operating policy was derived using s SDP(Stochastic Dynamic Programming) model and compared with the operating policy for the non-climate change case. The results showed that the oparating policy of the Skagit system is more sensitive to the change in the streamflow average than that in the streamflow standard deviation. The derived operating policies were also simulated using the synthetic streamflow scenarios and their average annual gains were compared as a performance index. To choose the best operating policy among the derived policies, a Bayesian decision strategy was also presented with an example. Keywords : climate change, reservoir operating policy, stochastic dynamic programming, Bayesian decision theory.

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Ordering Policy for Planned Maintenance with Salvage Value

  • Park, Young T.;Jing, Sun
    • International Journal of Quality Innovation
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    • v.7 no.3
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    • pp.15-23
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    • 2006
  • A spare ordering policy is considered for planned maintenance. Introducing the ordering, uptime, downtime, inventory costs and salvage value, we derive the expected cost effectiveness. The problem is to determine jointly the ordering time for a spare and the preventive replacement time for the operating unit which maximize the expected cost effectiveness. Some properties regarding the optimal policy are derived, and a numerical example is included to explain the proposed model.

Maintenance Limit Renewal Policy for Inferiority System based on Opportunity Cost (기회비용을 고려한 열화시스템의 보전한계갱신정책)

  • 박상민;김연수
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.17 no.32
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    • pp.233-242
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    • 1994
  • This study deals with the derivative adverse minimum for inferiority system depends on continuose operating under infinite planning horizon. This planning will be accomplished by maintenance limit renewal policy in consideration of opportunity cost which affects system by failure during operation periods and expected cost under nomal operation states. By the results, we will be expected incresing total efficiency for the system by optimal renewal policy.

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Determination of the Optimal Configuration of Operation Policies in an Integrated-Automated Manufacturing System Using the Taguchi Method and Simulation Experiments (다구치방법과 시뮬레이션을 이용한 통합된 자동생산시스템의 최적운영방안의 결정)

  • Lim, Joon-Mook;Kim, Kil-Soo;Sung, Ki-Seok
    • IE interfaces
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    • v.11 no.3
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    • pp.23-40
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    • 1998
  • In this paper, a method to determine the optimal configuration of operating policies in an integrated-automated manufacturing system using the Taguchi method and computer simulation experiments is presented. An integrated-automated manufacturing system called direct-input-output manufacturing system(DIOMS) is described. We only consider the operational aspect of the DIOMS. Four operating policies including input sequencing control, dispatching rule for the storage/retrieval(S/R) machine, machine center-based part type selection rule, and storage assignment policy are treated as design factors. The number of machine centers, the number of part types, demand rate, processing time and the rate of each part type, vertical and horizontal speed of the S/R machine, and the size of a local buffer in the machine centers are considered as noise factors in generating various manufacturing system environment. For the performance characteristics, mean flow time and throughput are adopted. A robust design experiment with inner and outer orthogonal arrays are conducted by computer simulation, and an optimal configuration of operating policies is presented which consists of a combination of the level of each design factor. The validity of the optimal configurations is investigated by comparing their signal-to-noise ratios with those obtained with full factorial designs.

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Cost Policy Effects of Economic Feasibility of 1kw household PEMFC System (요금 정책이 PEMFC 시스템 경제성에 미치는 영향)

  • Kim, Ki-Young;Hwang, Nam-Sun;Kong, Min-Seok;Kim, Hee-Su;Oh, Si-Doek
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.31-34
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    • 2007
  • Fuel cell with high electric efficiency has many probabilities of commercial use. Especially, polymer electrolyte or proton exchange membrane fuel cell (PEMFC) which is a low operating temperature and has less influence on $CO_2$ concentration is considered the power generation system of small building and household. We calculated the optimal operational plans of 1 kW household PEMFC power system based on daily electric and heat demand patterns of various size of apartments. Calculated results show that the economic feasibility of PEMFC power system is very sensitive to the cost policy of electricity and natural gas.

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The study of stochastic inventory model with setup cost and backorder rate (Setup cost와 Backorder rate를 고려한 확률적 재고모형에 관한 연구)

  • 유승우;서창현;김경섭
    • Proceedings of the Korea Society for Simulation Conference
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    • 2003.06a
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    • pp.129-134
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    • 2003
  • In this paper, we determine optimal reduction in the lead time and setup cost for some stochastic inventory models. And we propose more general model that allow the backorder rate as a control variable. We first assume that the lead time demand follows a normal distribution. And we assume that the backorder rate is dependent on the length of lead time through the amount of shortages. The stochastic models analyzed in this paper are the classical continuous and periodic review policy models with a mixture of backorders and lost sales. For each of these models, we provide a sufficient conditions for the uniqueness of the optimal operating policy. We also develop algorithms for solving these models and provide illustrative numerical examples.

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Performance Analysis of a Die FAbrication Process In Automotive Production (자동차 금형 생산공정의 물류분석)

  • 김상훈
    • Proceedings of the Korea Society for Simulation Conference
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    • 1998.10a
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    • pp.36-40
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    • 1998
  • Tool shop of the‘D’Motor Co.(DMC) fabricates dies for producing automotive press panels. In order to increase the production capacity of the tool shop, DMC established an FMS that consists of high-speed machines and a CMM at the tool shop in 1997. Due to the difference in machine capability among the existing machines and the new FMS it is needed to find an optimal way of allocating workloads among machines to maximize the production. In a way to solve this, we model the die fabrication process of the tool shop and analyze its performance by computer simulation. In this study, we at first identify the bottleneck processes of the die fabrication process under the current operation policy. Then, we derive some alternative operating policies applicable to the tool shop, and analyze the optimal operation policy by comparing the performance of the tool shop following each alternative policy.

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