• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.533-535
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• 1997

Chua's circuit is a simple electronic network which exhibits a variety of bifurcation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper we analyze a circuit obtained by replacing the parallel LC resonator in the Chua's circuit by lossless transmission line. By using the method of characteristics of this circuit we show that various periodic motions and chaotic motions can the attained according to parameter variations. From Chua's circuit with a lossless transmission line, a variety of chaotic attractors which are similar to those of the normal Chua's circuit are observed.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.627-629
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• 1997

In this paper, fuzzy logic system equipped with the back-propagation training algorithm as identifiers for nonlinear dynamic systems is described. To improve its performance, Jacob's delta-bar -delta rule is adapted in adjusting stepsize ${\alpha}$, and only y and ${\alpha}$ updating algorithm is suggested. In identifying and predicting the chaotic time series, suggested method is better than Li-Xin Wang's method,[1]

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.630-632
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• 1997

A fuzzy controller is based on o fuzzy logic that is so effective to represent uncertain phenomena of real world end mote its approximation. In this paper, A fuzzy controller which equipped with adaptive control algorithm is described. Proposed fuzzy controller applied to a boll on boon system shows a good performance.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.624-626
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• 1997

Canonical Chua's circuit is a simple electronic circuit which exhibits a variety of bifurcation phenomena and attractors. It consists of two capacitors, an inductor, two linear resistors, and a nonlinear resistor. When the circuit exhibits chaotic signals, the nonlinear resistor of canonical Chua's circuit may have three different voltage - current characteristics. In this paper, the design methodology for practical implementation of the nonlinear resistors which have all these characteristics is described. In addition, the effectiveness of result is shown by not only the MATLAB simulation but also the PSPICE simulation.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.897-899
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• 1997

The analysis of distribution line faults is essential to the proper protections of the power system. A high impedance fault does not make enough current to cause conventional protective devices. It is well known that undesirable operating conditions and certain types of faults on electric distribution feeders cannot be detected by using conventional protection system. This paper describes an algorithm using back-propagation neural network for pattern recognition and detection of high impedance faults. Fractal dimensions are estimated for distinction between random noise and chaotic behavior in the power system. The fractal dimension of the line current is also used as a indication of the high impedance fault.

• Journal of Information Management
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• v.24 no.3
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• pp.57-72
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• 1993

The purpose of this study is to investigate the present status of foreign academic journal collection in Korea and to explore the problem. In order to survey the current situation, the data from "Union Catalogue of Foreign Journals:Science & Technology, 1992" database constructed by Korea Institute of Industry and Technology Information has been analyzed. Major problems are poor collections, collection overlap, and lack of resource sharing.

• Journal of Information Management
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• v.24 no.3
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• pp.73-100
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• 1993

In attempting to respond to boolean retrieval system's limitations, this paper presents the design of a retrieval system using fuzzy logic. The fuzzy retrieval system introduces the weights of terms in the documents and in the query and makes use of them to determine how much relevant a document is to the given query. After comparing and analyzing the previous researches, an effective model of the fuzzy retrieval system is suggested and the performance of the system is evaluated through actual examples.

• Journal of the Korean Society for Library and Information Science
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• v.35 no.4
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• pp.197-216
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• 2001

The purpose of this study is to define a model for a national system of information services in the science, technology and industry sectors by assigning major roles to KISTI which was set up by the merge of KINITI and KORDIC. In order to determine these roles, this study investigates the characteristics and significance of national information services in the science, technology and industry sectors. and analyzes the functions of the information service institutes in Korea and foreign countries.

• Journal of Information Management
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• v.23 no.4
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• pp.39-58
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• 1992

Using information mapping methodology we will discover which of the multitude of information sources, services and systems used by corporation are actually resources and which are less important, redundant, or unnecessary. The discovery process of information resources will illuminate problems and opportunities related corporation's strengths and weeknesses in information quality, accessibility, performance, use, and effectiveness.

• Journal of Information Management
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• v.25 no.3
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• pp.1-27
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• 1994

This study intends to discuss the theories and case studies related to the selection and evaluation of information resources. The studies for the selection and evaluation of information resources can be divided into as follows : statistical methods, cost-effectiveness methods and expert system methods. Auther tried to discuss problems and prospects of the theoretical backgrounds and applications of expert system for the selection and evaluation of information resources.