• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.171-174
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• 1990

When load areas on a feeder are deenergized due to faults,operaters need to identify nelghboring feeders, try to restore customers and minimize out-of-service areas. These cases include knowledge of system states and various constraints such as voltage drop. This paper concerns the load transfer infault restoration. Also, it is considered the operating constraints such as line current capacity, relay trip current, transformer capacity, voltage drop and line loss. The expert system is able to propose the optimal load transfer method by anallzing system states and considering constraints.

• Environmental and Resource Economics Review
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• v.10 no.1
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• pp.1-23
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• 2001

This paper reviews a single trip decision to visit individual sites of a natural park within a random utility framework as an alternative to travel cost model. The model is applied to a 1998 survey of on-site visitors to Mu Deung Mt. neighboring Kwang Ju. city. Out of four sites considered, the model seemed to provide a reasonable description of behavior for three sites. In addition to travel costs as an implicit price, variables reflecting characteristics of each site also influenced decisions to visit the site. Moreover, benefits estimates derived from the RUM implied that visitors placed three times higher values on a site based on cultural inheritance compared with those of two recreational sites.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.781-783
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• 2004

최근 종단 호스트에서 나타나는 데이터 전송의 병목현상이 두드러지면서 종단 호스트에 관한 많은 연구가 진행되고 있다. 기존의 연구를 통해 종단 호스트의 병목현상의 원인으로 TCP의 비효율적인 버퍼관리가 제기되었다. 특히 임베디드 환경에서는 시스템 자원이 제한적일 수밖에 없기 때문에 TCP의 버퍼관리의 효율성이 매우 중요하다. 본 논문에서는 새로운 TCP 버퍼할당 기법인 RTBA(Rate-Based TCP Buffer Allocation) 기법을 제안하였다. RTBA는 플로우의 RTT(Round Trip Time), RTO(Retransmit Time Out), 패킷 손실율 둥을 고려한 TCP의 기대전송율을 기반으로 버퍼를 동적으로 할당함으로써 상대적으로 적은 버퍼를 사용하는 임베디드 환경에서도 다수의 TCP 플로우들이 높은 전송성능을 얻게 한다. 실험을 통해 제안한 RTBA 기법이 기존의 고정적인 버퍼할당 기법에 비해 우수한 성능을 보임을 확인할 수 있었다.

• 한국전기화학회:학술대회논문집
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• 2000.12a
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• pp.51-62
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• 2000

Large plastic Li-ion (PLI) cells (25 to 28-Ah) were fabricated for an EV application. The 28-Ah cells showed high specific energy (160 Wh/kg), high specific power (526 W/g), excellent round-trip energy efficiency $(92\%)$, and low self-discharge rate ($6\%$ in 30 days). A 25-Ah cell of an earlier design showed good cycle life of up to 750 cycles at $100\%$ DOD to $80\%$ of its initial capacity, while cycle life test of a 28-Ah cell of a later design is in progress. Preliminary safety tests were also carried out using 6-Ah cells of a similar electrode design giving very encouraging results for development of a safe hish-energy density PLI battery for EV application.

• Proceedings of the KIEE Conference
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• summer
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• pp.1385-1387
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• 2004

This paper presents a modelling methodology using fuzzy logic and train performance simulation for determining an economical running pattern for a high speed train which minimizes energy consumption under an given trip margin. The economical running pattern is defined with an economical maximum speed in traction phase, a speed at the end of coasting. As a case study, the simulation is carried out for an economical run of korea high speed train prototype, and the results of fuzzy model described.

• Journal of Navigation and Port Research
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• v.29 no.4
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• pp.305-312
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• 2005

Pick-up/delivery of consumer goods to offices, shops, and restaurants in order to support urban lives is one of the most vital activities in a city. With economic growth and technological innovation, a greater variety of goods have come to be supplied, and pick-up/delivery of consumer goods has become more complex. Efficient urban goods movement in Central Business District(CBD} starts with an efficient system for loading/unloading, and pick-up/delivery activities. Loading/unloading activity may be carried out on-street, or on especially designated space inside or outside buildings. Therefore, purpose of this study is to clarity the efficient urban goods movement in CBD(also called the pick-up/delivery activity) from the three different types of loading/unloading facilities. For this purpose, the differences in loading/unloading and truck-trip activity time of each loading/unloading facility was compared by performing the simulation analysis.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.29-32
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• 2004

Reliability is an important issue on the digital reactor protection system. This paper presents a Quantitative reliability evaluation method to find out an improvement effect of availability for the digital control module with a fault detection function. It is a reliability evaluation model which considers only the electronics parts ocurring a spurious reactor trip by the FMEA(Failure Mode Effect Analysis). Applying the previous and present methods to the reactor protection system, the availability factors are evaluated and compared.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.161-168
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• 1998

This paper presents an simulation methdology for determining an economical running pattern for a high speed train which minimizes energy consumption under an given trip time margin. The economical running pattern is defined with an economical maximum speed in traction phase, a speed at the end of coasting and a speed at the end of regenerative braking alone in braking phase. An economical run for subways is also described. As a case study, the simulation is carried out fer an economical run of high speed NamSeoul-Pusan line, and the results described. To do this, train performance simulation program is built and extended to be able to find an economical running pattern and then to simulate the defined economical run.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3595-3603
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• 2022

Nuclear safety-class DCS is used for nuclear reactor protection function, which is one of the key facilities to ensure nuclear power plant safety, the maintenance for DCS to keep system in a high reliability is significant. In this paper, Nuclear safety-class DCS system developed by the Nuclear Power Institute of China is investigated, the model of reliability estimation considering nuclear power plant emergency trip control process is carried out using Markov transfer process. According to the System-Subgroup-Module hierarchical iteration calculation, the evolution curve of failure probability is established, and the preventive maintenance optimization strategy is constructed combining reliability numerical calculation and periodic overhaul interval of nuclear power plant, which could provide a quantitative basis for the maintenance decision of DCS system.

• Journal of Korean Society of Transportation
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• v.7 no.1
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• pp.19-34
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• 1989

In general, Shopping centers are located in the center of transportation, which induce more traffic concentration than other facilities. As a result, it becomes to one of the aggravating factors of urban ＆ transportation problem such as traffic conjestion, parking problems. Thus, in planning shopping-center, it is desirable that consumer\`s trip pattern is should lie more carefully analyzed in order to alleviate the above problems. This study is aimed at finding the characteristics of shopping tripes and analyzing the choice behavior of shopping center and mode-to-shop. This study has developed a nested logit model in which consumers choose shopping center and mode-to-shop with a sequential structure. The model was estimated using household data from the 1989 May, Seoul metropolitan area and the 18 alternatives of shopping center and 5 mode alternatives. The estimated model have been evaluated and it may be concluded that this model for shopping trips is effective and fesible. The conclusion of this study are as fellows. 1. Out-of-vehicle travel time is more important factor affecting behavior of mode choice than in-vehicle travel time. 2. All of direct-elasticities for mode with respect to the travel time is more elastic than travel cost. 3. Accessibility to shop is more important factor affecting the choice of shopping center than parking space. 4. The value of out-of-vehicle travel time exceeds the value of in-vesicle travel time by 1.64 times.