• 대한전기학회논문지:전력기술부문A
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• 제50권6호
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• pp.265-274
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• 2001

Recently, the operation of power systems has become more difficult because the peak demand load is increasing continuously and the daily load factor is getting worse and worse. Also, the consideration of deregulation and global environment in electric power industry is required. In order to overcome those problems, a study on the planning and operation in power systems of dispersed generating sources such as fuel cell systems, photovoltaic systems and wind power systems, has been performed energetically. This paper presents a method for determining an optimal operation strategy of dispersed co-generating sources, especially fuel cell generation systems, considering thermal supply as well as electric power supply. In other words, the optimal operation of those sources can be determined easily by the principle of equal incremental fuel cost and the thermal merit of those sources can be also evaluated quantitatively through Kuhn-Tucker's optimal conditions. In additions, an priority method using the comparison of total cost at the peak load time interval is presented in order ot select the optimal locations of those sources. The validity of the proposed algorithms is demonstrated using a model system.

• 한국항해항만학회지
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• 제31권7호
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• pp.605-611
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• 2007

In order to become a mega hub port, major ports all over the world are making every effort to enhance their productivity through efficiency of internal operation. Accordingly, in order to enhance the competitiveness of a container terminal, an automated container terminal is considered as the best alternative. An automated container terminal is using such automated handling equipment as AGV(Automated Guided Vehicles) and ATC(Automated Transfer Crane). The efficient equipment operation plays a critical role in enhancing the productivity of an automated container terminal. In an automated container terminal, the most important equipments are AGV and ATC. Each block of containers with a vertical layout is generally operating two ATCs. The two ATCs can be crossed or not at each block. In the case of operating crossover ATC, it has an advantage of high flexibility that ATC work is possible at both TP(Transfer Point) of each block. But it has also a disadvantage that the yard has to be operated at a low storage level of containers in the terminal yard. Recently, for automated container terminals, which are being prepared for opening in Korea, they plan to use uncrossed twin ATC in order to make the storage level of their yards high at a low cost. Therefore, studies have to be made in order to increase the efficiency of twin ATC system based on the flexibility that the crossover ATC system has. This research aims to suggest an operation strategy to improve efficiency of twin ATC at each storage block in a yard.

• Journal of Power Electronics
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• 제18권5호
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• pp.1293-1302
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• 2018

Multiport power converters have recently become popular to researchers and engineers. However, more improvements are required in terms of their soft-switching operation, bidirectional operation, and integration. In this study, a bidirectional three-port three-switch DC-DC converter is proposed. The converter contains a low-current ripple port and ripple-free current port. Through the integrated structure, utilization of a coupled inductor, and a new switching strategy, the aforementioned specifications are achieved. A modified switching strategy is also utilized in the converter, which has resulted in the bidirectional operation of the converter between ports. Finally, a comprehensive analysis is presented, and the converter characteristics are validated by experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.513-515
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• 2000

This paper deals with a method for determining an optimal operation strategy of dispersed generating sources considering thermal merits. The optimal operation of these sources can be determined by the principle of equal incremental fuel cost. This paper presents an optimal operation strategy using the Kuhn-Tucker's optimal conditions and also an priority method to decide the optimal location of those sources in power systems. The validity of the proposed algorithms are demonstrated using a model system.

• 전자공학회논문지B
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• 제32B권3호
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• pp.89-99
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• 1995

One of the hardest problems that limit real application of production system is its slowness. One way to overcome this problem is to speed up the matching operation which occupies more than 90% of the total execution time. In this paper, we try to speed up the matching operation with parallel execution of a typical pattern matching algorithm, RETE, in a multiprocessor environment, This requires not only to make partitions of the rules but also to allocate the partitioned rules to processors, respectively. A partition strategy is proposed to make groups of similar rules by evaluating the similarity of rules according to the number of common conditions between rules. An allocation strategy is proposed to make the load of each processor even by assigning the different priority to the group of rules according to the expected amount of time required for matching operation. To compare with the existing methods, we perform simulation using OPS5 sample programs. The simulation results show that the proposed methods can improve the performance of production system.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.265-268
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• 2005

This paper discusses a strategy and status for development and operation of durability mock-up test facilities for offshore structures. The strategy is examplified and facilitated using an offshore transmission tower crossing the West sea and the Shihwha lake, which was designed and constructed 345kV T/L lines transmitting power from Yeong-Heung fossil power plant to Seoul metropolitan area. Various data for corrosion protection, aging, life-prediction of concrete and steel offshore structures can be obtained using the proposed mock-up test facility. Acquired data will be used for further research on durability, life-prediction, and retrofit of structures. It is important to maintain the safety of 345 kV Yeong-Heung transmission line crossing the Shihwha lake because the offshore structure is one of the critical electric facilities transmitting large power to the metropolitan area. Operation of the offshore transmission tower mock-up is expected to make a significant contribution to stable power supply.

• 대한전기학회논문지
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• 제43권7호
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• pp.1084-1092
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• 1994

An induction machine can be operated in the constant power region over an extended high speed range by means of field weakening. A conventional field weakening method is to set the flux reference inversely proportional to the rotor speed. With this method, however, the machines can't yield the maximum torque over the entire high speed range. In this paper, a new field weakening method for the field oriented induction machine drive by the voltage control strategy is presented. The proposed scheme ensures not only producting the maximum torque over the entire field weakening region but also the robust control independent on machine parameters. Also the smooth transition into the field weakening operation and fast dynamic response during transient operation can be obtained. Simulation and experimental results from a 3hp laboratory induction motor drive system are done to confirm the proposed control algorithm.

• 디지털융복합연구
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• 제11권10호
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• pp.403-409
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• 2013

본 논문은 미국 정부의 빅데이터 정책과 보안 이슈에 관해 고찰하였다. 빅데이터 R&D 이니셔티브 전략과 계획, NITRD 프로그램, 정부기관의 빅데이터 전략을 소개하였고, 또한 미군에서 빅데이터 운용환경, 군사 작전에 사용되는 빅데이터 정보, 주요 연구기관과 주제, 보안가이드라인 등에 대해 살펴보았다.

• 전기학회논문지
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• 제64권10호
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• pp.1493-1500
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• 2015

For efficient and economical train operation in low-density railway line, on-board oriented train control system, which reduces expensive wayside equipment, is being developed. In this paper, we discuss a tram signal priority strategy which enables efficient and safe train operation when the developing system is applied to train-tram railway environment. Based on the well-known transit signal priority strategies, we develop a tram signal priority algorithm and conduct simulations by using model-based systems engineering (MBSE) tool. Various considerations such as operation procedure, linkage to existing road traffic system, applicability with respect to crossroad types, and so on, are also dealt with.

• 한국수자원학회논문집
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• 제52권11호
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• pp.947-950
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• 2019

이 논문의 주요 특징은 초기강우 유입 시 일차 침전지 처리효율을 개선하기 위한 운전제어 전략을 제공하는 것이다. 최근 IoT 기술과 센싱 기술이 발전함에 따라 하수처리시설 운전제어를 위한 기반이 개선되고 있으며, 온라인 측정결과를 활용한 일차침전지 처리효율 개선에 따라 미처리 하수의 하천 유출을 최소화하고, 하수처리시설 운영효율 개선에기여할 수 있다.