• Title/Summary/Keyword: Flexible Capacity Management

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The Impact of Capacity Flexibility in a Rental Operation on the Financial Performance (렌탈 운영에서 용량 유연성 확보가 기업의 수익성에 미치는 영향)

  • Kim, Eungab
    • Journal of the Korean Operations Research and Management Science Society
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    • v.39 no.4
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    • pp.153-165
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    • 2014
  • We present a new framework for rental capacity management in which rental capacity is dynamically managed by means of temporary inventory addition/return. While serving customers with its own (native) capacity, the rental firm rents additional rental capacity from an upper echelon rental company so that it can avoid lost sales which may occur when stock is not sufficient, and returns it when stock becomes sufficiently large enough to cope with demands. Formulating the model as a Markov decision process, we investigate a flexible capacity addition/return policy that maximizes the firm's profit with respect to system costs. Numerical study indicates that rental operation with capacity addition/return can be economically favorable over rental operation without capacity expansion/return and can contribute the reduction in the size of native rental capacity.

Buffer System Design in the Flexible Manufacturing System Environments (유연생산(柔軟生産)시스템에서의 버퍼시스템 설계(設計))

  • Gang, Hui-Jeong;Kim, Hwan-Seong;Jo, Nam-Ho
    • Journal of Korean Society for Quality Management
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    • v.20 no.2
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    • pp.118-128
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    • 1992
  • The determination of appropriate buffer capacity is an important issue in the design of the advanced manufacturing systems and closely related to the system efficiency and flexibility. Work-in-process is usually not desirable. However, in reality, maintaining some capacity of buffer storage is inevitable in compensation for the machine blocking and break down. The objective of this paper is to present analytical methods and tools for the buffer capacity planning in the Flexible Manufacturing System Environments. The effects when machine blocking is critical factor are also discussed.

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A Lagrangian Relaxation Approach to Capacity Planning for a Manufacturing System with Flexible and Dedicated Machines

  • Lim, Seung-Kil;Kim, Yeong-Dae
    • Journal of the Korean Operations Research and Management Science Society
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    • v.23 no.2
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    • pp.47-65
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    • 1998
  • We consider a multiperiod capacity planning problem for determining a mix of flexible and dedicated capacities under budget restriction. These capacities are controlled by purchasing flexible machines and/or new dedicated machines and disposing old dedicated machines. Acquisition and replacement schedules are determined and operations are assigned to the flexible or dedicated machines for the objective of minimizing the sum of discounted costs of acquisition and operation of flexible machines, new dedicated machines, and old dedicated machines. In this research, the Problem is formulated as a mixed integer linear Program and solved by a Lagrangian relaxation approach. A subgradient optimization method is employed to obtain lower bounds and a multiplier adjustment method is devised to improve the bounds. We develop a linear programming based Lagrangian heuristic algorithm to find a good feasible solution of the original problem. Results of tests on randomly generated test problems show that the algorithm gives relatively good solutions in a reasonable amount of computation time.

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Optimal Investment of Capacity & Production Planning of Flexible Manufacturing System Considering Economies of Scope (범위의 경제를 고려한 유연생산시스템의 최적 용량 투자 및 생산 계획)

  • Lee Deok-Ju
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2004.10a
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    • pp.229-244
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    • 2004
  • This study addresses the problem of flexible technology acquisition in multi-product market when demands are uncertain. We confine the concept of flexibility to the ability of manufacturing system to produce a number of different types of products, called product-mix flexibility type. And an analytical model in which economies of scope is incorporated explicitly as a feature of flexible technology is presented to find the optimal investment decision to acquire flexible technology and optimal production planning. The characteristics of optimal investment strategy related to capacity and production planning are discussed.

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Distributed Energy System Connection Limit Capacity Increase Technology Using System Flexible Resources (계통유연자원을 활용한 분산에너지 계통접속 한계용량 증대 기술)

  • Jeong Min Park
    • Journal of Integrative Natural Science
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    • v.16 no.4
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    • pp.139-145
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    • 2023
  • Due to changes in the distribution system and increased demand for renewable energy, interest in technology to increase the limit capacity of distributed energy grid connection using grid flexible resources is also increasing. Recently, the distribution system system is changing due to the increase in distributed power from renewable energy, and as a result, problems with the limited capacity of the distribution system, such as waiting for renewable energy to connect and increased overload, are occurring. According to the power generation facility status report provided by the Korea Power Exchange, of the total power generation capacity of 134,020 MW as of 2021, power generation capacity through new and renewable energy facilities is 24,855 MW, accounting for approximately 19%, and among them, power generation through solar power accounts for a total portion of the total. It was analyzed that the proportion of solar power generation facilities was high, accounting for 75%. In the future, the proportion of new and renewable energy power generation facilities is expected to increase, and accordingly, an efficient operation plan for the distribution system is needed. Advanced country-type NWAs that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power in order to improve distribution network use efficiency without expanding distribution facilities due to the expansion of renewable energy. An integrated operating system is needed. In this study, in order to improve the efficiency of distribution network use without expanding distribution facilities due to the expansion of renewable energy, we developed a method that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power. We want to develop an integrated operation system for NWAs similar to that of advanced countries.

An Efficient Buffer Management in a Multi-Cell Flexible Manufacturing Systems (FMS 환경하의 효율적인 버버관리에 관한 연구)

  • 이정표
    • Proceedings of the Korea Society for Simulation Conference
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    • 1998.10a
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    • pp.128-132
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    • 1998
  • This research is concerned with buffer management in a multi-cell FMS(Flexible Manufacturing System) with an AGVS(Automated Guided Vehicle System). To reduce blocking and starving caused by breakdowns, variablility in process times, and diversity of part routing, buffer is needed. Due to the high per unit buffer cost, which primarily consists of floor space and equipment cost, the total capacity of buffers in an FMS is very limited. Therefore, proper buffer management can provide a high system efficiency. This paper presents a buffer management model for a multi-cell FMS with an AGVS and a simulation study to compare the proposed model to a conventional buffer management model in a job shop FMS.

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Application of Intelligent Technique for the Efficient Operation of the Flexible Manufacturing System (유연생산시스템의 효율적 운용을 위한 지능적 기법의 적용에 관한 연구)

    • Journal of the Korean Operations Research and Management Science Society
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    • v.24 no.2
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    • pp.1-15
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    • 1999
  • This research involves the development and evaluation of a work flow control model for a type of flexible manufacturing system(FMS) called a flexible flow line(FFL). The control model can be considered as a kind of hybrid intelligent model in that it utilizes both computer simulation and neural network technique. Training data sets were obtained using computer simulation of typical FFL states. And these data sets were used to train the neural network model. The model can easily incorporate particular aspects of a specific FFL such as limited buffer capacity and dispatching rules used. It also dynamically adapts to system uncertainty caused by such factors as machine breakdowns. Performance of the control model is shown to be superior to the random releasing method and the Minimal Part Set(MPS) heuristic in terms of machine utilization and work-in-process inventory level.

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Development of Storage Management Method for Effective Operation of Small Dams (소규모 댐의 효과적 운영을 위한 저수관리 기법 개발)

  • Kim Phil-Shik;Kim Sun-Joo
    • Journal of The Korean Society of Agricultural Engineers
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    • v.48 no.2
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    • pp.27-35
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    • 2006
  • Large dams are managed with operation standard and flood forecasting systems, while small dams do not have management method generally. Shortage of water resources and natural disasters due to drought and flood raised public concerns for management of small dams. Most of small dams are irrigation dams, which need diversified water uses. However, the lack of systematic management of small dams have caused serious water wastage and increased natural disasters. Storage management method and system were developed to solve these problems in small dams. The system was applied to Seongju dam for effective management. The storage management method was established considering hydrology simulation and statistical analysis using the system. This method can bring additional available water, even in the same conditions of the water demand and the supply conditions of watershed. It can improve the flood control capacity and water utilization efficiency by' the flexible operation of storage space.

Priority Scheduling for a Flexible Job Shop with a Reconfigurable Manufacturing Cell

  • Doh, Hyoung-Ho;Yu, Jae-Min;Kwon, Yong-Ju;Lee, Dong-Ho;Suh, Min-Suk
    • Industrial Engineering and Management Systems
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    • v.15 no.1
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    • pp.11-18
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    • 2016
  • This paper considers a scheduling problem in a flexible job shop with a reconfigurable manufacturing cell. The flexible job shop has both operation and routing flexibilities, which can be represented in the form of a multiple process plan, i.e. each part can be processed through alternative operations, each of which can be processed on alternative machines. The scheduling problem has three decision variables: (a) selecting operation/machine pairs for each part; (b) sequencing of parts to be fed into the reconfigurable manufacturing cell; and (c) sequencing of the parts assigned to each machine. Due to the reconfigurable manufacturing cell's ability of adjusting the capacity, functionality and flexibility to the desired levels, the priority scheduling approach is proposed in which the three decisions are made at the same time by combining operation/machine selection rules, input sequencing rules and part sequencing rules. To show the performances of various rule combinations, simulation experiments were done on various instances generated randomly using the experiences of the manufacturing experts, and the results are reported for the objectives of minimizing makespan, mean flow time and mean tardiness, respectively.

The tool switching problem on a flexible machine in a dynamic environment

  • Song Chang-Yong;Shinn Seong-Whan
    • Proceedings of the Safety Management and Science Conference
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    • 2001.05a
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    • pp.189-193
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    • 2001
  • This paper analyses the tool switching problem in the dynamic environment, where parts to be processed on a flexible machine arrive randomly. As the total number of tools required to Process a set of parts on the machine is generally larger than the available magazine storage capacity, tool switches between parts are usually necessary. We assume that tool switching must be made just before the processing of the parts. Since the time required for tool switches can be significant relative to processing time and cause the processing of parts to be delayed, it is desirable to minimize the number of tool switches. Therefore, we present one heuristic algorithm to minimize the total number of tool switches and the t)reposed heuristic is compared with the KTNS (Keep Tool Needed Soonest) policy on randomly generated problems.

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