• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.426-431
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• 1997

In this paper, a sensorless realization method is proposed for the magnetic levitation system. Also we design the robust servo controller which based on the two degree-of-freedom-control theory and H$\sub$.inf./ control theory for the system. From time responses, we confirm that the proposed sensorless method can be applied the magnetic levitation system. Also the designed controller has the good disturbance rejection and the reference tracking performance.

• 융합신호처리학회논문지
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• 제2권3호
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• pp.57-64
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• 2001

본 논문은 시스템의 불확실성과 외란의 불확실성에도 불구하고 원하는 시스템 성능을 만족할 수 있는 강인한 제어기 설계에 대하여 서술한다. QFT(Quantitative Feedback Theory)에 근거한 강인한 제어기 설계과정은 시스템 파라미터 변동과 설계사양을 고려하여 결정되는 템플레이트, 한계조건 그리고 루프형성을 거친다. 설계된 제어기의 성능을 입증하기 위해 파라미터 변동에 매우 민감하고, 비선형성이 강하며 불안정한 특성을 지닌 도립진자시스템에 대하여 적용한다. 설계된 제어기에 대한 시뮬레이션과 실험결과들은 파라메파 변동과 외란에 강인한 제어성능을 보인다.

• Asia pacific journal of information systems
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• 제25권3호
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• pp.500-518
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• 2015

The present research aims to identify the relationship between trust and distrust in an online business environment. To clarify the concepts, cognitive-affective personality system theory was introduced, through which five types of psychological units were proposed. In developing the research model based on the theory, technical effectiveness of the system and content truthfulness of the website were selected as two key stimuli for the coding process of online users. Trust and distrust were selected as mediating factors that generate consequent behaviors. Finally, purchase intention served as a final dependent variable. Assuming that trust and distrust emerge in psychologically different stages, this study hypothesized the mutual causal relationship between trust and distrust, indicating that the relationship will be determined by their contextual emphasis on each dimension. To validate, a survey was conducted with 307 online shopping mall users. Results show that stimuli were more significantly associated with trust. Trust is therefore a more cognitive construct than distrust, and the path from trust to distrust is stronger than that from distrust to trust. This finding implies that the cognitive aspect of trust is stronger than that of distrust. Distrust is rather more affectively emerging than trust.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
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• pp.129-132
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• 2001

본 논문은 3 관성시스템의 진동억제를 위한 강인한(robust) 제어기의 설계법을 제안하고 이를 simulation 을 통하여 확인하는데 있다. 일반적으로 관성 시스템의 제어 문제는 결국. 시스템 자체에서 발생하는 진동을 최대한 억제하면서 빠른 시간에 원하는 위치에 출력을 가져가는 데 있다. 이 경우 문제로 되는 것은 시스템의 모델링 과정에서 발생하는 플랜트의 불확실성과 parameter 변동이다. 여기서는 일반적인 강인한 제어기 설계 이론의 하나인 $H_{\infty}$ 이론이 가지는 단점인 제어기의 보수성을 극복하면서, 동시에 출력의 과도응답특성을 개선하기 위한 방법으로 $H_2$ 이론을 병용하고 이를 LMI 이론으로 해석하였다. 이 과정에서 3 관성시스템에 LMI 이론을 적용하기 위한 일반화플랜트의 모형을 제시하고 이것의 유효성을, 모델의 불확실성과 parameter변동을 동시에 고려한 simulation을 통하여 확인하였다.

• 한국문헌정보학회지
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• 제21권
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• pp.249-290
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• 1991

Theoretical developments in the information retrieval have offered a number of alternatives to traditional Boolean retrieval. Probability theory and fuzzy set theory have played prominent roles here. Fuzzy set theory is an attempt to generalize traditional set theory by permitting partial membership in a set and this means recognizing different degrees to which a document can match a request. In this study, an experimentation of a document retrieval system using the fuzzy relation matrix of the keywords is described and the results are offered. The queries composed of keywords and Boolean operaters AND, OR, NOT were processed in the retrieval method, and the method was implemented on the PC of 32bit level (30 MHz) in an experimental system. The measurement of the recall ratio and precision ratio verified the effectiveness of the proposed fuzzy relation matrix of keywords and retrieval method. Compared to traditional crisp method in the same document database, the recall ratio increased $10\%$ high although the precision ratio decreased slightly. The problems, in this experiment, to be resolved are first, the design of the automatic data input and fuzzy indexing modules, through which the system . can have the ability of competition and usefulness. Second, devising a systematic procedure for assigning fuzzy weights to keywords in documents and in queries.

• 정보보호학회논문지
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• 제12권3호
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• pp.129-139
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• 2002

인터넷의 확장에 따라서 네트워크를 통한 침입이 증가되고 있다. 이에 따라 네트워크를 통한 침입에 대하여 즉각적으로 탐지하고 대처하는 기술이 필요하게 되었다. 본 논문은 인터넷의 특성을 악용하여 침입하는 공격들을 탐지하기 위하여 Adaptive Resonance Theory2(ART2) 이론을 이용한다. 정상적인 packet과 여러 가지 공격툴을 사용하여 생산한 인위적인 공격 패킷에 대하여 ART2를 학습한 후 실험한 결과와 기존의 방식들과 비교 분석하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.301-307
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• 2005

In this study, simplified whirl flutter analyses using quasisteady aerodynamic theory have been performed for a 2-DOF tilt-rotor system with both pitch and yaw motions of a rotor-nacelle. The present dynamic system consists of the rotor (propeller), forming the gyroscopic and aerodynamic element, supported horizontally by a pylon that is pivoted at some wing attachment point. Several design parameters (or rotor-nacelle system are considered and the effect of whirl flutter stability are also investigated for various design parameters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.17-19
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• 2001

In this paper, eigenvalue perturbation theory and its applications for the augmented system matrix are described. This theory is quite useful in the cases where any change in a system parameter results in signifiant changes to most of the elements of the augmented matrix or where the forming of sensitivity matrix so complicate. And AMEP(augmented matrix eigenvalue perturbation) for the excitation system parameters are computed for analysis of small signal stability of KEPCO 215-machine 791-bus system.

• 한국시뮬레이션학회논문지
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• 제9권1호
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• pp.55-66
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• 2000

This paper deals with complex system theory to describe land combat situation using EINSTein (Enhanced ISAAC Neural Simulation Tool) simulation model. Many studies have shown that existing Lanchester equations used in most wargame models does not describe changes of combat units, real land warfare situation and qualitative factors in combat. Future warfare will be a non-linear combat with various weapon system and complex combat units. EINSTein models is an agent-based simulation tool using complex system theory. We have compared and tested land combat results with Lanchester models and EINSTein models. The results have shown that EINSTein model has a possibility to apply and analyze land warfare more properly than Lanchester models.

• 한국시스템다이내믹스연구
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• 제5권1호
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• pp.5-33
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• 2004

This study explores how agents would make decisions responding to control mechanism in contractual relationship of their firm. Focusing on agent's averse behavior against control, system dynamics model for agent's opportunistic behavior is developed in view of agent theory and control theory. This SD model shows that control mechanism by contracts doesn't always play a positive role on corporate decision-making process and Control, especially in the over-controlled contracts, often makes a paradox accelerating agent's opportunistic behavior unexpectedly. This paradox provides us both theoretical and practical implications for the relationship between control mechanism and autonomous behavior for sustainable corporate management.