• Proceedings of the KIEE Conference
• /
• 1990.07a
• /
• pp.121-124
• /
• 1990

Distance relaying is one of the most commonly used protection schemes in the high voltage transmission systems. In this scheme, coordination between the primary and backup relays is very critical for the power system security. This paper reports an rule-based methodology for checking and correction of miscoordination problems in the distance relaying. Diagnosis rules achieving an accurate but simple checking have been developed through the geometric analysis of the impedance characteristics of the distance relays. Heuristic rules having the pratical power for miscoordination correction are suggested. The proposed method has proved very effective through the several case studies on the actual systems.

• Fashion & Textile Research Journal
• /
• v.11 no.1
• /
• pp.93-102
• /
• 2009

The purpose of this study was to analyze the factor of fashion behavior and to identify fashion behavior differences according to demorgraphic/physical characteristics and parents' background of male college student in Dalian, China. The data were collected via a self-administered questionnaire from 250 male college students living in Dalian, China in June 2007. Data analysis method were used to Crombach's a, reliabilty, factor analysis, frequency analysis, ANOVA, and Sheffe's test for the post hoctest. The results of this study were as follows: Fashion behavior factors were analyzed into 6 factors such as fashion satisfaction oriented, high price oriented, fashion leader oriented, practical fashion oriented, others defendence oriented. There were significant difference in demographic variables such as age, major and physical variables such as height, weight, clothing size and parents' background such as education, job, and income.

• Journal of the Ergonomics Society of Korea
• /
• v.16 no.1
• /
• pp.63-71
• /
• 1997

This paper presented an experiment which examined eye and hand movement characteristics of novice and experienced workers in the press operation. Continuous recordings of eye and hand movements were made on five novice operators and five experienced operators in press operation. Significant difference between the novice and the experienced operators was observed in eye fixation time, eye movement patterns, hand dwell time, and eye-hand coordination. Also, differences were observed in spatial distribution of eye fixations during the die-closing portion of a stroke. There were no significant differences between the novice and the experiencedoperators in the eye and the hand movement time. The results could be used to establish a guide determining the method and training period to train the novice operators.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.3
• /
• pp.1245-1249
• /
• 2017

Recently, unusual transformer failures have been reported in 25kV power systems connected with a VCB and transformer. In this study, performance of the protection system, dielectric strength of the transformers, characteristics of switching surges and resonance phenomena were analysed and assessed. All investigations regarding the insulation breakdown of the transformers were carried out by simulations, laboratory tests, factory tests and on-site measurements in order to thoroughly investigate the root causes. Furthermore, experimental methods for investigating the resonance phenomenon were derived and tests were conducted applying the derived method to recreate the phenomenon in the transformer. It is found that resonance between the transformer and switching surge generated by closing a VCB can initiate the breakdown of internal windings of a transformer.

• The KIPS Transactions:PartB
• /
• v.10B no.3
• /
• pp.249-256
• /
• 2003

The most important problems in the multi-agent system are to accomplish a goal through the efficient coordination of several agents and to prevent collision with other agents. In this paper, we propose a new control strategy for succeeding the goal of the prey pursuit problem efficiently. Our control method uses reinforcement learning to control the multi-agent system and consider the distance as well as the space relationship between the agents in the state space of the prey pursuit problem.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2006.11a
• /
• pp.247-250
• /
• 2006

급속도로 변화하는 환경에 적응하기 위해서 환경의 변화에 대한 요구와 신속한 응답능력을 향상시키고, 에이전트간 의사결정의 지속시간을 줄이기 위하여 에이전트간 효율적인 조정에 관련된 의사결정을 하기위한 대안(alternative)결정과 사용자의 선호도를 어떻게 유도할 수 있는가라는 문제가 요구된다. 본 논문에서는 사회적(Pareto) 최적성이라는 관점에서 의사결정의 행동을 효과적으로 시뮬레이트하기 우해 퍼지 의사결정에 기반한 멀티에이전트의 효율적인 조정방안을 제안한다. 또한 제안하는 방법에서는 가중치를 사용하여 각 속성이 멀티에이전트와 관련하여 최적의 대안을 생성하고, 퍼지 의사결정에 기반한 멀티에이전트의 의사결정방법에 기존의 방법보다 가중치를 사용한 방법이 높은 신뢰도를 가지면서 더 빠른 의사결정을 한다는 것을 확인하였다.

• Journal of the Korea Society for Simulation
• /
• v.11 no.4
• /
• pp.91-105
• /
• 2002

The attackers on Internet-connected systems we are seeing today are more serious and technically complex than those in the past. So it is beyond the scope of amy one system to deal with the intrusions. That the multiple IDSes (Intrusion Detection System) coordinate by sharing attacker's information for the effective detection of the intrusion is the effective method for improving the intrusion detection performance. The system which uses BBA (BlackBoard Architecture) for the information sharing can be easily expanded by adding new agents and increasing the number of BB (BlackBoard) levels. Moreover the subdivided levels of blackboard enhance the sensitivity of the intrusion detection. For the simulation, security models are constructed based on the DEVS (Discrete EVent system Specification) formalism. The intrusion detection agent uses the ES (Expert System). The intrusion detection system detects the intrusions using the blackboard and the firewall responses these detection information.

• Proceedings of the KSME Conference
• /
• 2005.11a
• /
• pp.202.1-202.1
• /
• 2005

• 전기의세계
• /
• v.19 no.6
• /
• pp.49-55
• /
• 1970

전력선과 통신선이 가까이 있는 지역에서는 유도장해로 인한 통신측 피해가 크게 문제 된다. 전력선 및 통신선의 유도차폐 또는 이상전압에 대한 보호기술이 잘 발달되고 상호협조가 원만한 선진제국에서도 좀 더 양질의 통화를 위해서 꾸준히 연구되고 있는 문제이다. 본 고에서는 유도허용 한도에 대하여 기술하고 근본적인 유도전압 계산에 대하여 적용되는 계산식을 간추려보고자 한다.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.5
• /
• pp.1049-1056
• /
• 2016