• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1993년도 추계학술대회발표논문집; 서강대학교, 서울; 25 Sep. 1993
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• pp.24-30
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• 1993

When modeling a complex system we use an event tree to analyze propagation of failure. An event tree cannot represent the statistical interrelationships among parameters, but it can be represented as a statistically identical influence diagram so that parameter updating can be easily performed. After updating parameters we can calculate posterior distribution of the failure rate for each path. But exact distribution requires considerably complex numerical integration. We propose an approximation method to calculate the posterior and derive the predictive distribution of the time to next failure. Finally we introduce the system which implements our methodology.

• 대한전기학회논문지
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• 제39권2호
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• pp.119-132
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• 1990

To design protection coordination for an electric power distribution system, an expert system is developed, using both the veteran expert's heuristics and the guide book for the distribution facility operation considering feeder configuration, service route, load characteristics fault current and load current. The expert system developed in this papaer determines the type of protective device(clearing current and sequence). The location and rating change of protective device in the old feeder is realized by using old database. Current(T-C) curves of various kinds of protective devices are stored in Knowledge Base (KB). The expert system is developed on a 32 bit personal computer using PROLOG, AutoCAD,dBASEIIIPLUS and FORTRAN. To compute the fault current and loadflow, FORTRAN is used.

• 전기학회논문지
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• 제58권1호
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• pp.7-13
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• 2009

This paper presents benefits of multi-agent system approach and its application to the distribution automation system. Special attention is devoted to the description of hardware and communication platform used to upgrade the conventional distribution automation system structure. Service restoration of primary distribution system is selected as an example of the multi-agent system application. Application of the algorithm for multi-agent based service restoration technique is disclosed in detail. Real field test in Gochang test center of KEPCO has been performed to establish the feasibility of proposed technique.

• Smart Structures and Systems
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• 제12권6호
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• pp.641-659
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• 2013

In this paper is studied the influence of the uncertain mass distribution over the floors on the choice of the optimal parameters of a hybrid control system for tall buildings subjected to wind load. In particular, an optimization procedure is developed for the robust design of a hybrid control system that is based on an enhanced Monte Carlo simulation technique and the genetic algorithm. The large computational effort inherent in the use of a MC-based procedure is reduced by the employment of the Latin Hypercube Sampling. With reference to a tall building modeled as a multi degrees of freedom system, several numerical analyses are carried out varying the parameters influencing the floors' masses, like the coefficient of variation of the distribution and the correlation between the floors' masses. The procedure allows to obtain optimal designs of the control system that are robust with respect to the uncertainties on the distribution of the dead and live loads.

• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.66-80
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• 2001

In brake systems, a proportioning valve(P. V), which reduces the brake line pressure on each wheel cylinder for the anti-locking of rear wheels, is closely related to the safety of vehicles. However, it is impossible for current P. V. s to completely control brake line pressure because, mechanically, it is an open loop control system. In this paper we describe an electronic brake force distribution system using a direct adaptive fuzzy controller in order to completely control brake line pressure using a closed loop control system. The objective of the electronic brake force distribution system is to change the cut-in-pressure and the valve slop of the P. V in order to obtain better performance of the brake system than with mechanical systems.

• 대한전기학회논문지:전력기술부문A
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• 제49권3호
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• pp.118-123
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• 2000

This paper presents an efficient algorithm for loss reduction and load balancing by sectionalizing switch operation in large scale distribution system of radial type. We use Genetic algorithm and Kruskal algorithm to solve distribution system reconfiguration. Genetic algorithm is used to minimize objective function including loss and load balancing items. Kruskal algorithm is used to satisfy the radial condition of distribution system. The experimental results show that the proposed method has the ability to search a good solution regardless of initial configuration and size of system.

• 조명전기설비학회논문지
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• 제17권3호
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• pp.87-94
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• 2003

배전계통에서의 사고 발생시 정전으로 인한 수용가의 손실을 최소로 하기 위하여 정전구역에 대한 신속한 복구가 이루어져야 한다. 본 논문에서는 배전계통의 정전복구를 위한 전문가 시스템을 제안하였다. 제안된 전문가 시스템은 복구과정에서 전문가의 경험적 규칙을 이용함으로써 복구에 소요되는 스위칭 횟수를 최소화 하도록 하였다. 복구 과정은 일반적인 위상구조 지식 기반의 응용을 통해 전문가 시스템의 상태공간에서 타당한 경로를 찾는 문제로 표현하였다. 또한, 다양한 배전계통 구조를 고려하기 위해 다중 부하절체 기법을 제안하였다.

• 동력기계공학회지
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• 제2권1호
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• pp.25-30
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• 1998

In order to investigate the droplet size distribution and Sauter Mean Diameter in a ultra high pressure diesel spray, fuel was injected with ultra high pressure into the environments of high pressure and room temperature by an Electronic Hydraulic Fuel Injection System. Droplet size was measured with the immersion liquid sampling technique. The immersion liquid was used a mixture of water-methycellulose solution and ethanol. The Sauter Mean Diameter decreased with increasing injection pressure, with a decrease environmental pressure (back pressure) and nozzle diameter. Increasing the injection pressure makes the fuel density distribution of the spray more homogeneous. An empirical correlation was developed among injection pressure, air density, nozzle diameter and the Sauter Mean Diameter of spray droplets.

• 대한산업공학회지
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• 제3권2호
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• pp.41-55
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• 1977

The physical distribution system is composed of all the activities associated with getting products from the factory to the consumer through the firm's channels of distribution. An increasing amount of attention has been recently devoted to the component problems associated with distribution system analysis. This paper analyzes effect of system parameters which are safety factor of depot's stock, limitation of direct supply from shop stock to customer and ordering quantity on the physical distribution cost and the evaluated items by the Simulation. The distribution system simulator views system as being composed of three structural entities, presents a case study of a Chemical manufactures and carried on one year computer running.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.206-208
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• 2002

Distributed generation (DG) is predicted to play an increasing role in the electric power system of the near future. Distributed generation is by definition that is of limited size (roughly 10MW or less) and interconnected at the substation, distribution feeder or customer load levels. The effects of generation sources within a distribution network on the system losses are investigated in this paper. WLAV state estimation is performed with the composite distribution system containing DG. Simulations with test cases are performed and the results are presented, using IEEE34 bus radial distribution system.