• Title/Summary/Keyword: Efficiency of operations

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A study on Location-Allocation Problem with the Cost of Land (입지선정비를 고려한 입지-배정 문제에 관한 연구)

  • 양병학
    • Journal of the military operations research society of Korea
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    • v.25 no.2
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    • pp.117-129
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    • 1999
  • We consider a Location-Allocation Problem with the Cost of Land(LAPCL). LAPCL has extremely huge size of problem and complex characteristic of location and allocation problem. Heuristics and decomposition approaches on simple Location-Allocation Problem were well developed in last three decades. Currently, genetic algorithm(GA) is used widely at combinatorics and NLP fields. A lot of research show that GA has efficiency for finding good solution. Our main motive of this research is developing of a GA in LAPCL. We found that LAPCL could be reduced to trivial problem, if locations were given. In this case, we can calculate fitness function by simple technique. We propose fourth alternative genetic algorithm. Computational experiments are carried out to find a best algorithm.

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Optimized Installation and Operations of Battery Energy Storage System and Electric Double Layer Capacitor Modules for Renewable Energy Based Intermittent Generation

  • Min, Sang Won;Kim, Seog Ju;Hur, Don
    • Journal of Electrical Engineering and Technology
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    • v.8 no.2
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    • pp.238-243
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    • 2013
  • In this paper, a novel approach for optimized installation and operations of battery energy storage system (BESS) and electric double layer capacitor (EDLC) modules for the renewable energy based intermittent generation is presented for them to be connected with an electric power grid. In order to make use of not merely the high energy density of battery but also the high power density of EDLC modules, it is very useful to devise the hybrid system which combines BESS and EDLC modules. The proposed method adopts the linear programming to calculate the optimized capacity as well as the quadratic programming to transmit the optimal operational signals to BESS and EDLC modules. The efficiency of this methodology will be demonstrated in the experimental study with the real data of wind speed in Texas.

Structural Analysis and Performance Evaluation of Quick Change Power Chuck for Lathe Operations (선반용 급속 교환 파워 척의 구조해석 및 성능평가)

  • 유중학
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.5
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    • pp.90-95
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    • 1999
  • Chucking for workpieces is very important for productivity and efficiency in lathe operations. In point of productivity top jaws of the chuck should be changed as quickly as possible in order to reduce idle times wherever workpieces are regripped. A quick change power chuck which can change top jaws quickly by using a jaw change handle without any assembly/disassembly processes of screws is analyzed for this study. strength and stiffness of top jaws by centrifugal force are considered for the design. Structural analysis for the chuck is executed and the finite element method is introduced using MSC/NASTRAN software. Also, the performance of the chuck is evaluated by experiments.

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Sequencing in Mixed Model Assembly Lines with Setup Time : A Tabu Search Approach (준비시간이 있는 혼합모델 조립라인의 제품투입순서 결정 : Tabu Search 기법 적용)

  • 김여근;현철주
    • Journal of the Korean Operations Research and Management Science Society
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    • v.13 no.1
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    • pp.13-13
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    • 1988
  • This paper considers the sequencing problem in mixed model assembly lines with hybrid workstation types and sequence-dependent setup times. Computation time is often a critical factor in choosing a method of determining the sequence. We develop a mathematical formulation of the problem to minimize the overall length of a line, and present a tabu search technique which can provide a near optimal solution in real time. The proposed technique is compared with a genetic algorithm and a branch-and-bound method. Experimental results are reported to demonstrate the efficiency of the technique.

An Algorithm for Portfolio Selection Model

  • Kim, Yong-Chan;Shin, Ki-Young;Kim, Jong-Soo
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2000.04a
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    • pp.65-68
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    • 2000
  • The problem of selecting a portfolio is to find Un investment plan that achieves a desired return while minimizing the risk involved. One stream of algorithms are based upon mixed integer linear programming models and guarantee an integer optimal solution. But these algorithms require too much time to apply to real problems. Another stream of algorithms are fur a near optimal solution and are fast enough. But, these also have a weakness in that the solution generated can't be guaranteed to be integer values. Since it is not a trivial job to tansform the scullion into integer valued one simutaneously maintaining the quality of the solution, they are not easy to apply to real world portfolio selection. To tackle the problem more efficiently, we propose an algorithm which generates a very good integer solution in reasonable amount of time. The algorithm is tested using Korean stock market data to verify its accuracy and efficiency.

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A Study on the IT Evaluation Framework in perspective of IT competency of Enterprise (기업 정보화 역량 관점의 정보화 수준 평가체계에 관한 연구)

  • Cha, Jeong-Hun;Lee, Byeong-Yul;Sin, Seon-Do;Im, Chun-Seong
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2008.10a
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    • pp.487-491
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    • 2008
  • An informatization is recognized as core factors to reinforce business competitiveness such as formation of a new business relation, prior occupation of the strategic superiority and being a step ahead from the purpose to improve only the whole efficiency of enterprise. But existed evaluation framework has focused on the visible aspect of all the conditions to create the input and output. In previous studies, it's hard to know that how IT affect business value creation. Therefore, this study presents the evaluation of IT structure and IT competency as drivers and inhibitors of informatization and suggests new IT evaluation framework which can estimate IT competency. The new IT Evaluation Framework was verified through survey with experts.

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Automatic Support Structure Generation for Stereolithographic Rapid Prototyping (SLA를 이용한 신속시작작업을 위한 지지대 자동생성 시스템의 개발)

  • Hur, Junghoon;Lee, Kunwoo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.10
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    • pp.3068-3078
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    • 1996
  • stereolithography is a process used to rapidly produce polymer components directly from a computer representation of the part. There are several considerations to be made for the efficient use of the process. Especially, the necessity of support structures, which prevent the part from warping, sagging, or parachuting and toppling as the elevator moves up and down in the resin, is one concern. After solidification, the support structures must by removed in the end. Bacause this post-treatment process is often performed manually, the more the support structures, the more it increases the finishing operations. Especially for a complicated part, the removal operations may be difficult, take so much time, and even reduce the accuracy of the product. Thus it is important to efficiently generate the efficient support structure for each part geometry. This paper proposes a procedure to automatically generate the supprot structures focused on accuracy, efficiency, convenience, and generation speed.

Allocation of aircraft under demand by Wets' approach to stochastic programs with simple recourse

  • Sung, Chang-Sup
    • Journal of the Korean Operations Research and Management Science Society
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    • v.4 no.1
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    • pp.59-64
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    • 1979
  • The application of optimization techniques to the planning of industrial, economic, administrative and military activities with random technological coefficients has been extensively studied in the literature. Stochastic (linear) programs with simple recourse essentially model the allocation of scarce resources under uncertainty with linear penalties associated with shortages or surplus. This work on a problem with a discrete random resource vector, "The allocation of aircraft under uncertain demand" given in (1), is easily and efficiently handled by the application of the recently developed Wets' algorithm (8) for solving stochastic programs with simple recourse, which approves that such class of stochastic problems can be solved with the same efficiency as solving linear programs of the same size. It is known that the algorithm is also applicable to stochastic programs with continuous random demands for their approximate solutions.

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A Method for Determining the k Most Vital Arcs in Maximum Flow Problem (최대유통문제에서 k-MVA를 결정하는 방법)

  • 정호연
    • Journal of the military operations research society of Korea
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    • v.25 no.2
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    • pp.106-116
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    • 1999
  • The purpose of this study is to present a method for determining the k most vital arcs in the maximum flow problem using genetic algorithms. Generally, the problem which determine the k most vital arcs in maximum flow problem has known as NP-hard. Therefore, in this study we propose a method for determining all the k most vital arcs in maximum flow problem using genetic algorithms. First, we propose a genetic algorithm to find the k most vital arcs removed at the same time and then present the expression and determination method of individuals compatible with the characteristics of the problem, and specify the genetic parameter values of constitution, population size, crossover rate, mutation rate and etc. of the initial population which makes detecting efficiency better. Finally, using the proposed algorithms, we analyzed the performance of searching optimal solution through computer experiment. The proposed algorithms found all alternatives within shorter time than other heuristic methods. The method presented in this study can determine all the alternatives when there exists other alternative solutions.

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SHE&Q 시스템의 통합 방안에 관한 연구

  • Gang In Seon
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2002.05a
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    • pp.515-519
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    • 2002
  • As the number of the company to acquire the certifications of ISO 9001/1400, OHSAS 18001(not official standard) is increasing, it is needed to construct a integrated business management system for the efficient application of the certifications. In this circumstances the integrated construction of the SHE & Q system so called, for Safety, Health, Environment and Qualify can take a part for the communication in the customer, the company convenience and the interested parties(the worker. the supplier and the provider). In case that each certification systems are integrated, the problems of the redundancy in the management processes and the conflicting demands are able to be solved and the efficiency of the restricted management resources fan be raised as the complexity of the redundancies in the certification management is simplified. This paper deals with the integrated strategies, its convenience and its expecting merit and demerit for the efficient application of the certification parties haying the various characters.

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