• 전기학회논문지
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• 제58권9호
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• pp.1689-1694
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• 2009

In a previous paper, the characteristics of ECC (earth continuity conductor) have been analysed for reducing the level of induced sheath voltage considering the dimension and position of ECC, the spacing between ECC and three phase cables, and the use of two ECC conductors at the single point boned section of underground power cable system. From these results, the study conditions for optimal installation has been selected such as installation section, conductor size and etc. In this paper, 5 cases which are set by possible installation conditions are tested based on previous research results. Finally, the optimal installation method of ECC is selected on underground power cable systems.

• 산업공학
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• 제14권2호
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• pp.111-119
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• 2001

A tandem AGV system is based on partitioning all the stations into non-overlapping single vehicle closed loops with additional stations provided as an interface between adjacent loops. For an efficient use of this configuration, it is required to solve the load routing problem(LRP), which is primarily based on the fact that a load may be handled by several vehicles and moved through several loops before it reaches its destination. In this paper, a heuristic based on genetic algorithm(GA) is first developed to solve LRP. The first model obtains the optimal route of each job and the optimal direction of each loop when the vehicle in each loop travels unidirectionally. The second GA model obtaines the optimal polling sequence of the empty vehicle in each loop, when the vehicle can move bidirectionally.

• 대한전기학회논문지:전력기술부문A
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• 제50권8호
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• pp.379-387
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• 2001

This paper shows that we can make simple modifications to an existing optimal power flow(OPF) algorithm that minimizes generation costs in order to solve the maximization of social welfare objective of the OPF in a competitive electric power market. We have illustrated the potential for the use of OPF in light of the marked impacts on nodal prices and generation/demand allocation levels among competing suppliers. This paper can provide all market players with the transparent information that ensures sufficient control over producers and consumers in case of economic of secure operation with transmission line outage while maximizing the sum of participants social benefit of participating in the electricity energy market.

• 대한전기학회논문지
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• 제41권8호
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• pp.914-921
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• 1992

In this paper, we introduce a Walsh network and an LMS algorithm, and show how these can be realized as an adaptive equalizer. The Walsh network is built from a set of Walsh and Block pulse functions. In the LMS algorithm, the convergence factor is an important design parameter because it governs stability and convergence speed, which depend on the proper choice of the convergence facotr. The conventional adaptation techniques use a fixed time constant convergence factor by the method of trial and error. In this paper, we propose an optimal method in the choice of the convergence factor. The proposed algorithm depends on the received signal and the output of the Walsh network in real time.

• 한국정보처리학회논문지
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• 제6권3호
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• pp.615-621
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• 1999

On the aspect of on-time and development resource use, it is very important to predict the software release time during the software development process. In this paper, we present the optimal release problem based on the evaluation indicator and cost evaluation. And also we show the optimal release point considered with both of them. We applied the Exponential Software Reliability Growth Model(E-SRGM) and Testing-effort dependent Software Reliability Growth Model(Te-SRGM) and decided the software release time according to software reliability indicator. As a result of two models comparison, we verify the Te-SRGM is more adopted in our switching system software.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.102-105
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• 1993

The objective of this study is to solve the operation scheduling problem of plural battery energy storage systems (BESS), and to find useful intonation from its result. Unlike conventional energy storage system, BESS has on hardware characteristics such as high efficiency, fast-acting response and operational loss. Considering rate constraints of thermal unit power as well as hardware characteristics of BESS, the operation scheduling has an intricated problem. In order to solve this optimization problem, we use successive approximations dynamic programming. In two types of operation, the proposed algorithm is applied to test system. one is daily optimal operation, the other weekly optimal operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.202-204
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• 2003

This paper suggests an optimal parameter setting method by use of parametric protectability index, as the objective function. In this paper, a gradient based optimization method is used under the assumption that the initial values of a parameter is in a convex set including the optimal value, which is verified by a plenty of simulation studies. The proposed method is applied to a sample distribution network to shows its effectiveness.

• 대한산업공학회지
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• 제18권1호
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• pp.47-62
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• 1992

This paper describes a procedure for optimizing the route selection and production conditions in alternate process plans under a cellular manufacturing environment. The type of production is mainly production-to-order which deals with unexpected products as the changes factor. The flexible cellular manufacturing can be viewed as a complete unification of both flexible manufacturing process and flexible production management. The integrated problem for designing flexible cellular manufacturing associated with determining the optimal values of the machining speeds, overtime, and intercell flow is formulated as Nonlinear Mixed Integer Programming(NMIP) in order to minimize total production change cost. This is achieved by introducing the marginal cost analysis into the NMIP, which will compute the optimal machining speed, overtime, intercell flow, and routing. The application of this procedure offers greater flexibility to take advantage of the cellular manufacturing due to the optimum use of resources. A solution procedure for this problem was developed and a numerical example is included.

• 조명전기설비학회논문지
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• 제28권7호
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• pp.34-40
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• 2014

In this paper, we want to know the optimal replacement cycle(time) for this study was performed. The optimal preventive replacement age can be fond by finding the value of time that minimizes the cost function(model of Barlow and Jardine). In addition, The reliability of the relay according to the service environment were studied. The use of the exchange relay period is longer, and maintenance cost rate(per hour) may increase, and also the reliability may cause a decline. In addition, considering the preventive maintenance and purchase order, a representative relay(RAX-L440-A type) life was calculated.

• 품질경영학회지
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• 제24권2호
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• pp.25-43
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• 1996

This paper presents the optimal and practical constant-stress accelerated life test plans for the lognormal lifetime distribution tinder assumptions of intermittent inspection and Type-I censoring. In an optimal plan, the low stress level and the proportions of test units allocated at each stress are determined under given inspection scheme and number of inspections such that the asymptotic variance of the maximum likelihood estimator of a certain quantile at use condition is minimized. Although the practical plan adopts the same design criterion, it involves three rather than two overstress levels in order to compromise the practical deficiencies of the optimal plan. Computational experiments are conducted to choose an allocation plan and a inspection scheme of the practical plan and to compare with test plans over a range of parameter values.