• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.5
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• pp.451-456
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• 2015

In this paper, an observer-based decentralized fuzzy controller is designed for discrete-time interconnected fuzzy systems. Based on the fuzzy subsystem of the interconnected fuzzy system, the observer-based decentralized fuzzy controller is considered. By using the fuzzy subsystem and the observer-based decentralized fuzzy controller, the closed-loop system is obtained. From the closed-loop system, the stability condition with the maximum interconnection bound is developed, and its sufficient condition is represented as the linear matrix inequality (LMI). Finally, the numerical example is provided to verify the effectiveness of the proposed technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.42-48
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• 2006

In this paper a joint detection method for other cell interference cancellation is proposed in the next generation hybrid TD-CDMA mobile communication systems. A joint detection technique, a most characteristic feature of hybrid TD-CDMA mobile communication systems. retrieves users' data in the same time slot simultaneously with the elimination of multiple user interference. Previously a two stage joint detection method was proposed to cancel other cell interference as well as multiple user interference in the target cell. However the previous scheme does not have concrete ways to recognize other cell users who give major interference to the target cell. Thus all users in neighbor other cells has to be jointly detected and it causes huge complexity of the two stage joint detection. In this paper a method is proposed to perform two stage joint detection according to users' interference with the target cell. Performances of the proposed scheme are investigated through simulations and compared to the previous method the proposed method has no performance degradation and also lower the complexity of two stage joint detection significantly.

• Digital Contents
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• no.3 s.70
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• pp.44-46
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• 1999

현대적인 의미에서의 CRM은 정보시스템의 구축 및 활용과 유기적인 관계를 가지고 있으므로 정보시스템 기술이 없이는 CRM이 성립될 수 없고 CRM을 전개해가는 과정은 정보시스템 구축과 전략의 수립 및 집행을 결합한 과정으로 파악해야 한다. 따라서 일반적인 CRM 방법론에서의 절차는 전략 계획의 수립, 전략의 실행, 전략 실행결과의 평가라는 전략계획 실행 과정상에 정보시스템의 계획, 분석, 설계, 구축, 운영이라는 정보시스템 기발 과정이 결합된 형태가 된다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1781-1782
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• 2008

본 논문은 시간 지연을 가지는 이산 시간 비선형 상호 결합 시스템의 분산 퍼지 출력 궤환 제어기의 설계에 대해 연구한다. T-S(Takagi-Sugeno) 퍼지 모델 기법을 이용하여 퍼지 상호 결합 시스템을 구한다. 이를 바탕으로 분산 퍼지 출력 궤환 제어기를 설계하고, 폐루프 시스템의 안정도 충분 조건을 선형 행렬 부등식 (LMI)의 형태로 나타낸다. 설계된 이득값을 통하여 상호 결합 시스템이 안정화됨을 모의실험을 통하여 보인다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.45-47
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• 2000

객체관계형 데이터베이스 시스템(objet-relational database management system: ORDBMS)은 멀티미디어 데이터베이스, 지리정보 시스템(geographical information system), CAD/CAM 공학 데이터베이스 등 새로운 응용 분야에 적합한 차세대 데이터베이스 시스템이다. 본 논문에서는 한국과학기술원 첨단정보기술연구센터에서 개발해 오고 있는 오디세우스 객체관계형 멀티미디어 DBMS의 아키텍쳐와 오디세우스의 확장 버전들에 대해서 설명한다. 오디세우스는 다양한 멀티미디어 응용들을 빠르게 지원하기 위해서 엔진 수준에서 필요한 프리미티브를 구현하는 밀결합 아키텍쳐를 채택하고 있다. 현재 밀결합 아키텍쳐로 이미 구현됐거나 개발중인 시스템으로는 텍스트 정보 검색 기능을 밀결합한 정보검색용 DBMS의 오디세우스/IR과 공간 정보 검색 기능을 밀결합한 GIS용 DBMS인 오디세우스/Geo가 있으며, 다양한 멀티미디어 엔진 프리미티브들을 추가적으로 개발중이다. 특히 오디세우스/IR은 성공적으로 실용화되어 현재 여러 사이트에서 사용되고 있으며 이는 오디세우스/IR 아키텍쳐의 우수성을 간접적으로 증명하는 실례들이다. 또한 최근에는 사용자가 쉽게 고성능의 웹 DBMS 응용 프로그램을 작성하도록 도와주는 웹과 DBMS 연동 도구를 개발하였다. 본 논문에서는 이들 시스템에 대한 특징들을 소개하고자 한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.519-519
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• 2012

유도 결합 플라즈마에서 안테나 전류의 측정을 통해 시스템 저항을 계산하여 플라즈마 소비 전력을 구하는 기존의 방법은 정밀한 전류 측정의 한계를 가지고 있다. 본 연구에서는 유도 결합 방전 시스템에서 정합회로와 코일 사이에 설치된 전류 측정 장치를 사용하여 방전된 상태에서의 인가한 전력에 따른 코일 전류를 측정하였고, 방전되지 않은 상태에서 방전되었을 때와 같은 전류를 흐르게 인가 전력을 조절하였다. 이때의 측정값이 시스템이 소비하는 전력이라고 할 수 있다. 결과적으로 기존의 시스템 저항의 오차를 고려하지 않기 때문에 개선된 소비 전력값을 좀 더 용이하게 구할 수 있었다.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.67-76
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• 2009

Recently, the active interaction control (AIC) system was proposed as a semi-active control system. The AIC system consists of a primary structure and an auxiliary structure. The objective of the AIC system is to control the response of the primary structure through engagement and disengagement between the primary and auxiliary structures. Previous switching control algorithms have been shown to be effective in reducing the response of the primary structure. However, they have the main drawback of requiring an excessive engagement-disengagement frequency and high interaction force. In this paper, the regions in which the switching is activated and the regions in which the switching is deactivated are described separately, to effectively determine the engagement or the disengagement. The general relationship between the switching regions and the deactivated switching regions selected according to the engagement-disengagement conditions is described within the newly-developed comprehensive switching framework. The proposed engagement-disengagement conditions are designed within a comprehensive switching framework, to reduce engagement-disengagement frequency and interaction force. Furthermore, the effect of a control sampling period on the AIC system is explained in terms of the engagement-disengagement frequency. The effectiveness of the proposed algorithms and the effect of the control sampling period are considered for a single degree of freedom model under free vibration. It is observed that increasing the duration of stay by using a large control sampling period prevents the AIC system from activating the possible chance of switching. The proposed algorithms are shown to be effective, both in restricting ineffective switching and in reducing interaction force.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.1
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• pp.9-18
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• 2003

In this paper, we analyzed the throughput of DS/CDMA system applying packet combining scheme combined with Type- I Hybrid ARQ scheme over AWGN channel and Nakagami fading channel with RAKE receiver. As the parameter for analysis, we used number of combined packet(L), number of diversity branch$({L_c})$, fading index(m), and length of packet(N), and used CRC-12 error detection code and (2,1,3) convolutional code. As a results, we found that throughput of system over Nakagami fading channel with RAKE receiver was superior to throughput over AWGN channel, and throughput of system decreases rapidly as channel degrades when number of combined packet(L) was increased. However throughput of system with the combining scheme was achieved even at low ${E_b}/{N_o}$. Also, we found that throughput of system was increased when fading index(m) and number of diversity branch$({L_c})$ were increased, but it was decreased when number of user(K) and length of packet(N) were increased.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.18-25
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• 1997

The feedforward control algorithm for active noise control exhibits high stability and performance robustness. But it has a slow convergence speed and requires a correlated reference signal. Broadband active control systems typically use feedback control in order to increase the convergence speed and to avoid the problems associated with obtaining and decoupling a suitable reference signal. However, it is well known that conventional feedback control systems have a gain-bandwidth limitation and stability problem. This paper presents the new system based on the combination of both feedforward and feedback system in order to increase the convergence speed. The proposed system uses a proposed control algorithm termed "optional-summed" algorithm in which the "optional summed reference signal" comprised of weighted sum of an original reference signal and a eror signal, is used as an input to an adaptive system. Thus, the proposed system can have faster convergence speed and better performance than either feedforward or feedback system using the Filtered-x LMS algorithm as almost equivalent complexity of computation as it. Several simulation results demonstrating the good properties of the proposed adaptive system as well as verifying the analytical results are also presented in the paper.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.6
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• pp.780-785
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• 2007

This paper proposes the decentralized dynamic output feedback controller for discrete-time nonlinear interconnected systems using Takagi-Sugeno (T-S) fuzzy model. Through T-S fuzzy model of each subsystem, the decentralized dynamic output feedback controller is designed. By the closed-loop subsystems with controller, it represents the linear matrix inequality (LMI) for stability of whole interconnected system. The value of control gain are obtained by LMI. An example is given to show the experimentally verification discussed throughout the paper.