• Journal of the Korean Data and Information Science Society
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• v.23 no.4
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• pp.825-832
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• 2012

We propose a novel way of forecasting the market shares of several brands simultaneously in a multiplicative competitive interaction model, which uses kernel regression technique incorporated with kernel machine technique applied in support vector machines and other machine learning techniques. Traditionally, the estimations of the market share attraction model are performed via a maximum likelihood estimation procedure under the assumption that the data are drawn from a normal distribution. The proposed method is shown to be a good candidate for forecasting method of the market share attraction model when normal distribution is not assumed. We apply the proposed method to forecast the market shares of 4 Korean car brands simultaneously and represent better performances than maximum likelihood estimation procedure.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.78-88
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• 2018

The liberalization of electricity market and environmental concerns are the major driving forces for the development of Distributed Generation (DG). The mode of grid-connected wind power generation is becoming popular and has matured as a reliable DG technology. The voltage generated by the wind generator is stepped up to the higher voltage by the transformers before connecting to the grid. Operating algorithm of the differential relays for transformer protection used in the wind farms need to be modified to take care of the dynamic nature of fault current caused by the intermittent nature of the wind power. An algorithm for the differential relay is proposed in which dual slope characteristics are adjusted with varying fault level situation according to the wind generator in service as well as with the wind speed. A case study conducted for a typical wind farm shows that the proposed method avoids mal-operation of the differential relay in varying wind power conditions.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.597-600
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• 2001

멀티에이전트 시스템은 분산적이고 개방적인 인터넷 환경에 잘 부합된다. 멀티 에이전트 시스템에서는 각 에이전트들이 자신의 목적을 위해 행동하기 때문에 에이전트간 충돌이 발생하는 경우에 조정을 통해 협력할 수 있어야 한다. 그러나 기존의 멀티 에이전트 시스템에서의 에이전트 간 협력 방법에 관한 연구 방법들은 동적 환경에서 서로 다른 목적을 갖는 에이전트간의 협동 문제를 올바로 해결할 수 없다는 문제가 있었다. 본 논문에서는 신경망과 강화학습을 이용하여 목적 패턴을 정확히 결정할 수 없는 복잡하고 동적인 환경에 멀티 에이전트의 시스템 모델을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1521-1524
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• 2003

인터넷 기반의 정보교환 표준으로 급부상한 XML에 의해 대용량의 XML 문서를 효율적으로 저장하고 관리하는 방법이 필요하게 되었다. 이에 따라 XML 문서를 저장하기 위한 백엔드 데이터베이스 시스템으로 RDBMS와 ORDBMS 그리고 Native XML 등의 XML 저장 시스템이 출현하였다. 그러므로 이들에 대해 유형별로 용도와 비용대비 성능에 관한 저장, 조회 및 관리 차원의 비교는 시급하다. 본 논문에서는 XML 문서를 저장, 관리하기 위한 RDBMS와 Native XML 데이터베이스에서의 XML 문서 접근방법에 대하여 비교 분석한다. 유형별 각 시스템 접근방식의 장단점을 비교 한 후 효과적인 XML 문서의 저장 기능 개발을 위해 상용 DBMS의 유형을 대표하는 Oracle 8i와 Tamino를 선택하여 성능을 비교한다.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.334-336
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• 2003

This paper describes the influences of the large scaled wind farm interconnected with 154 kV power networks on the operational characteristics of distance relay applied in the transmission line. The wind farm composed of wind turbine generators are one of the great energy sources: they can supply the power into an interconnected network not only the normal conditions, but also the fault conditions of power network. Therefore, the distance relay applied in the transmission tine may mal-operate due to the contribution of wind farm. This paper presents the operational characteristics of distance relay for the fault occurred in the transmission line interconnected with wind farm. Simulation results show that it is difficult to recognize the fault location due to the power output of wind farm.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1114-1116
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• 2003

Voltage sags are known as a serious problem causing mal-operation of equipment like computers, process controllers and adjustable-speed drives. In this paper, characterization of voltage sag and an overview of methods used in the mitigation of voltage sags are presented. Moreover a fast detection method for voltage disturbances is explored. The algorithm is based on the theory that allows a set of three-phase voltages be converted the d-q value. The utility input voltages are sensed and then converted to some quantities in the d-q transformation. And the difference between reference value and input value are showed that some disturbances happened in the system.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.120-123
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• 1993

This paper presents the developing a new algorithm for detecting the Back fed Earth Fault in three wire-unigrounded distribution system by zero sequence admittance. So called "Backfed Earth Fault" of the electric power distribution line refers to a class of earth faults that the load-side line only is grounded, following after the distribution line broken into two parts, the source-side and the load-side. Because its mechanism differs from that of other earth faults, it is therefore, required to examine. This paper deals with the detailed software of the digital protective relay for Backfed earth fault. In order to prove that the proposed schemes is good, we performed off-line simulation using data from EMTP and ETSA(Electrcity Trust Of South Austrilia). It is shown that the suggested algorithm is never mal operated.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.8
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• pp.1239-1247
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• 2002

Consumers' purchase intention related with price reduction is important factor for the successful marketing strategy of electronic commerce as a new marketing channel. Therefore, the purpose of this study was to assess the difference of consumers' attitude(purchasability and perceived need) depending upon purchasing variables, and to investigate how consumers' attitude influence on purchase intention with price reduction in the internet shopping mal1. For research method, 400 questionnaires were distributed to subjects who were 20 to 39 years old; and among the returned questionnaires 347 were usable. Data were analyzed by t-test, regression analysis, frequency with SPSS 10.0. Results of this study were as follows: First the results showed that purchasability and Perceived need affect Purchase intention according to off-price percentage, and brand and clothing style in discount. Second, there were significant differences in purchasability, and perceived need according to off-price percentage, and brand in discounts. However, there were no significant differences in purchasability and perceived need according to clothing style in discounts.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1321-1327
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• 2014

Faulted section identification is one of the most important function in distribution automation systems. Conventional over current detection based fault indicators frequently mal-operate due to the reverse fault current from the renewable energy resources. This paper present a new faulted section identification method based on the fuzzy decision making technique. In order to establish feasibility of the proposed method, case studies using Matlab Simulink has been performed.

• Journal of Information Technology Services
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• v.5 no.3
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• pp.45-62
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• 2006

The research is intended to satisfy two interesting research purposes: one is to examine activities of both BSC adotion phase and implementation phase under carrying BSC project. The second purpose is to analyze the influence from those activities towards innovating business world. This study was conducted thru online questionnaires via online survey system during 3 months for targeting mainly on business users and consultants. The findings of the study suggest that employee's involvement, BSC information sharing, collaboration cross task related teams have major roles to operate BSC successfully. From findings, KPI choice, top-down goal allocation, budgeting allocation have strong influences on upgrading business innovations. Those businesses like to considering adoption of BSC can benefit from the findings of the research.