• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.217-219
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• 2005

배전계통의 소극적인 원격감시제어 만이 가능한 소규모 배전자동화 시스템이 1998년 처음 설치된 이후로 지금에 이르기까지 한국의 배전자동화 시스템은 종합 배전자동화로 이름만 변모 한 것이 아니라 기술수준과 표현능력에 있어서 비약적인 발전을 거듭하고 있다. 선로운영자의 계통상황 인식을 수월하게 하기위한 실지도상의 선로 표현창과 함께 기술검토를 위한 단선도 창이 추가되었고, 이를 통해 배전망 최적운영을 위한 다수의 기술검토용 운영프로그램들이 포함되어지고 있다. 본 논문에서는 고장발생시 그 위치를 추정하는 알고리즘을 연구하고 이를 배전자동화 시스템에 시험 적용한 사례를 소개한다.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.6-8
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• 2002

In this paper present Autonomous Adaptive Digital Over Current Relay which acts autonomous setting using voltage and current measured by relay in the change of power systems. Automation of relay setting is required for distribution automation although manual relay setting is used at present. This paper presents Autonomous Relay Setting which knows change of the power system and acquires setting element using the Recursive Least Squares. Relay setting is very difficult work. But proposed relay is expected to decrease burden of relay setting using acquired information of power system change and autonomous setting. Also fast protective ability is expected according to change of power system.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.193-195
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• 2002

In this paper, a communication module is proposed to be applied to communication between over current relay (OCR) agents in multi agent protection system. A multi agent system can achieve a global goal beyond the ability of each individual agent by working together, in which it is the prerequisite for each agent to be able to exchange or share information or processing status with other agent. The proposed communication module is purposed to enable not only each agent to bring about its own goal, but also the whole protective system to provide much improved coordinated protection. It is applied to a self adaptive protection system for a distribution network using multi agent concept to show its effectiveness.

• Journal of Korean Elementary Science Education
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• v.27 no.4
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• pp.341-355
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• 2008

The purpose of this study was to analyze the measuring abilities of elementary school students by using a microgenetic method. The participants were seven elementary students in the fourth grade. To analyze their measuring abilities, students attended three physical quantities measuring tasks such as length, volume, and time task by six times. Results were as follows. First, in the measuring length task, students selected appropriate measuring instruments but they didn't consider measuring amounts. And as their measuring experience increased, they desirably improved management abilities of measuring instruments. In the measuring volume task, they dealed with measuring instruments, but not very well. And these tendency were maintained. In the measuring time task, they were not measure exactly. Second, as their measuring experience increased, their ability to read the scale marks improved. However, they had difficulties in estimating the volume between scale marks. Results indicate that, elementary students need to basic education about measuring instruments, their usage, and scale reading ability for their science experiment courses in schools.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2303-2310
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• 2009

Defense systems are needed to prevent catastrophic failures of a power grid due to cascaded events. Cascaded events can be attributed to improper operations of protective relays. Especially, it is the most dangerous problem that trips of backup relays by overload. In this paper, a new algorithm of predicting Zone 3 acting time of distance relay is proposed using the real time synchronized data from PMUs on the transmission system when the power system is danger. In the proposed, some part of the power system are outage when some unexpected fault in the power system, the algorithm will monitor the impedance locus of distance relay. At this time, if there is a big change of Impedance locus, the algorithm will calculate the Zone 3 acting time of the distance relay by the over load. In the case studies, the estimation and simulation network have been testified and analysed in Matlab Simulink.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.241-243
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• 2002

Recently, great efforts are concentrated on the autonomous, adaptive protection schemes with advanced artificial intelligence and digital technology. It is highly required for a next generation protective system not only to detect and to clear a fault, but also to fit itself to the changing environment. In this paper it is suggested an evaluation method for the protection ability of a protective system in a distributed system. The suggested method is of bottom-up scheme, in other words, protection ability is estimated from the lowest level of parameters in each protective devices to the highest level of the whole protective system. This feature makes it possible to evaluate the protection ability either for the protective device(or a system), or for a protected system. And, in addition, it is enabled that the protectability concept can be applied in the design stage of a protective system for a distribution network. The proposed method is applied to a simple distributed network to show its effectiveness.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.196-201
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• 1997

Assuming that Asp225 is the substrate specificity determinant of Achromobacter pretense I (APl) which is lysine-specific serine protease, the 225th residue was substituted for other amino acids with a hope that the substrate specificity of a mutant API is altered. Furthermore, to maturate preform of mutant API autocatalytically, Lys(-1) was also replaced by Met, Asp, or Glu. However, all the mutants were not expressed, or accumulated as inactive precursor proteins. This result implicats that Asp225 plays a critical rol in restricted substrate specificity as a lysylendopeptidase but the substrate specificity of API is not determined only by the nature of residue 225.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.2
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• pp.226-233
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• 2014

This study is to develop a subject substitute STEAM program which can be applied instead of classes in school field and to seek development plan of a subject substitute STEAM program based on that. The program was developed by experts on science education and teachers who participated in developing STEAM program business conducted by the Korea Foundation for the Advancement of Science and Creativity and one 6th grade located in small and medium city was chosen for application. As a result, the subject substitute STEAM program attracted students' interest and helped to understand for them. In addition, the development plan was found that teachers' participation is very important, an inquiry activity related to real life is to be included and enough activity time is helpful in students' understanding, when developing a subject substitute STEAM program.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.891-893
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• 1997

In this paper an intelligent power transformer protective relaying algorithm based on Fuzzy Decision-Making is presented. The introduced protection algorithm contains several internal fuzzy rule-bases including bpa(Basic Probability Assignment: m) which are subject to off-line pre-installation by the analysis of the transformer transient characteristics for detecting the internal fault. Dempster-Shafer's rule of combination is used for the inference method with rules to decide the situation of a transformer, The proposed algorithm immunes to the saturation of transformer, inrush conditions, over excitation, and external fault. The included results of testing show practically sufficient sensitivity and selectivity of the proposed algorithm.

• Proceedings of the Safety Management and Science Conference
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• 2009.11a
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• pp.125-144
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• 2009

Korean logistics industry have been focused on transportation business. However, with the expansion of the electronic commerce and on-line shopping, delivery service is now dramatically growing. Despite the expansion of logistics market, the domestic logistics industry have significant structural problems such as low productivity comparing with the advanced countries, relatively high cost and shortage of human resources and lack of professionalism of people in the industry. Logistics companies reallocate employees, use subcontractors, expand consignment and training the employees to overcome the labor shortages but it has some limits. In recognition of the importance of labor in the logistics industry, financial support and investment have increased. Logistics companies tend to hire consultants, set up logistics department or R&D center in order to establish highly productive logistics process and system so it is viewed that there will be considerable demands of human resources in the logistics industry. This study indicates implications and development direction of human resources in the logistics industry by looking into prospect and characteristic of the industry, employment status, training programs and qualification requirements.