• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.69-75
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• 2006

디지털 테크놀로지의 비약적인 발전으로 우리는 연령과 계층을 막론하고 실생활 측면에서 사용자 환경의 변화, 디자인 시각의 변화 등 많은 변화의 사례들을 인지할 수 있다. 그 중에서도 최근 유아들의 전유물이었던 완구 시장이 학생, 성인들 대상으로 마케팅이 확장되면서 기존에 없었던 보다 지능적인 시스템과 다양한 콘텐츠를 보유하고 혁신적인 인터페이스를 갖춘 디지털 인텔리전트 브릭(Digital Intelligent Brick)완구가 시장을 빠르게 확대해 나가고 있다. 이처럼 아날로그 브릭에서 디지털 브릭으로의 새로운 변화를 주도한 대표적인 예로는 MIT와 공동연구로 개발된 로보틱스 인벤션 시스템(Robotics Invention System)인 레고(Lego)의 '마인드스톰'을 들 수 있다. 인텔리전트 브릭 시스템 완구는 Stud와 Tube의 Elements로 이루어진 기본적이고 반복적인 재료의 속성에서 시스템의 무한한 가변성과 사용자의 다양한 조건에 맞춘 인터페이스를 적용함으로써 창의적 결과물로의 확장성을 나타내고 있다. 본 연구에서는 디지털 테크놀로지를 기반으로 한 사용자중심 콘텐츠 속성을 지닌 인텔리전트 브릭 시스템에서의 시스템 구조 가변성 및 인터페이스 디자인의 확장성, 그리고 사용자 인터랙션 측면에 관하여 분석해 보고자 한다. 이를 토대로 인텔리전트 브릭 시스템이 향후 디지털 디자인 산업의 다양한 측면에서 보다 적극적으로 활용될 수 있는 기초를 제시하는 데 본 연구의 목적이 있다고 할 것이다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.600-603
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• 2007

We propose a method to estimate the asymptotic stability region(ASR) of a mismatched uncertain variable structure system with a bounded controller. The uncertain system under consideration may have mismatched parameter uncertainties in the state matrix. Using linear matrix inequalities(LMIs) we estimate the ASR and we show the quadratic stability of the closed-loop control system in the estimated ASR. We also give a simple LMI-based algorithm for estimating the ASR. Finally, we give a numerical example in order to show the effectiveness of our method.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.2
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• pp.30-39
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• 1989

Variable structure control (VSC) systems control the state vectors using sliding regime (SR) constructed switching logic, switching plane and control law. Saturation function switching logic is used to improve the drawback which occurs in traditional sign function switching logic. Switching plane with time-varying parameter is proposed to improve the drawback which occurs in switching plane with constant parameter and it is suggested the control law which has time-varying parameter. The stability of VSC system controlled by proposed time-varying SR is discussed, and the good control behavior was shown through computer simulation using proposed SR.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.1
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• pp.1-5
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• 1996

In the unification method of classical linear control and variable structure control, a problem that the error between the actual plant output and the nominal plant output exists consistently is solved by replacing the nominal plant with an adaptive observer. Since the exponentially convergent adaptive observer is used, the adaptive observer output converges to the actual plant output rapidly. So, the error does not exist after all and as a result the performance degradation of the control system is prevented.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1813-1822
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• 1993

An algorithm of fuzzy variable structrue control is proposed to design a closed loop fuel-injection system for the emission control of automotive gasoline engines. Fuzzy control is combined with sliding control at the switching boundary layer to improve the chattering of the stoichiometric air to fuel ratio. Multi-staged fuzzy rules are introduced to improve the adaptiveness of control system for the various operating conditions of engines, and a simplified technique of fuzzy inference is also adopted to improve the computational efficiency based on nonfuzzy micro-processors. The proposed method provides an effective way of engine controller design due to its hybrid structure satisfying the requirements of robustness and stability. The great potential of the fuzzy variable structure control is shown through a hardware-testing with an Intel 80C186 processor for controller and a typical engine-only model on an AD-100 computer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.65-75
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• 1996

A pilot plant, which is simplified the hot water heating control system of a large scale residential building, is used to investigate the effects of control methods and operating conditions on the system performance and to compare control characteristics. Digital variable structure controller(DVSC) and digital PI controller are implemented to control the speed of the circulating pump for the pilot plant using PC. For the DVSC, a control algorithm is suggested, which using a nonlinear sliding surface and a PID sliding surface outside and inside of output error boundary layer, respectively. Smith predictor algorithm is used for the compensation of long dead time. The suggested DVSC yields improved control performance compared with existing DVSC using linear sliding surface only. the system responses with the suggested DVSC shows good responses without overshoot for various operating conditions and robust under external disturbances compared with digital PI controller.

• Journal of Advanced Navigation Technology
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• v.18 no.5
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• pp.476-482
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• 2014

Recently, with the growth of various sensor applications, the need of wireless communication systems which can support variable data rate is increasing. IEEE 802.15.4 LR-WPAN system using 2.45 GHz frequency band is very popular for the sensor applications. However, since LR-WPAN only supports the data rate of 250 kbps, it has a limit to be applied to various sensor networks. Therefore, we define the preamble structure which can support the data rates of 31.25 kbps, 62.5 kbps, 125 kbps, and present the low-complexity hardware architecture for time synchronizer based on double-correlation algorithm which can resist the CFO (carrier frequency offset). Implementation results show that the proposed time synchronizer include the logic slice of 18.36 K and four DSP48s, which are reduced at the rate of 79.1% and 99.4%, respectively, compared with existing architecture.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2289-2292
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• 2002

최근 웹을 기반으로 한 문서의 전자화가 이루어지면서 기존의 전통적인 펜기반 교정 시스템 또한 온라인상의 전자 문서 환경에 맞게 변화하고 있다. 이러한 펜기반 입력 기법을 사용하는 교정 시스템에서는 일반문서와 달리 웹 문서의 구조정보를 고려한 편집이 지원되어야 하며 또한 교정부호와 텍스트간의 정확한 영역 인식이 이루어져야 한다. 본 연구에서는 온라인 교정 시스템 모델링을 통하여 온라인 환경에 적합한 교정 부호를 정의하고, 교정 대상 텍스트 영역을 편집 가능한 단위로 구분하여 효율적인 편집 연산이 이루어 질 수 있도록 하였다. 또한 웹 기반의 구조문서(HTML/XML) 편집 환경을 고려하여 편집으로 인한 문서의 구조 정보 변경을 지원하기 위하여 텍스트를 비구조 및 구조정보 텍스트로 분류하여 정의하였다. 본 연구에서는 이러한 모델에 기반하여 교정 부호의 특성에 따른 가변적인 편집 텍스트 영역 인식 규칙 모델을 정의하여 교정 부호와 편집 텍스트 영역간의 모호성을 최소화하고, 편집으로 인한 문서의 구조 정보 변경을 지원하는 시스템을 구현하였다. 결과적으로 온라인 웹 문서 환경에서 펜기반의 모호한 교정 부호의 입력을 인지적인 관점에서 해석하여 보다 정확한 교정 작업 수행을 지원하도록 하였다.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.465-470
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• 2009

This study investigated the water saving technology for the toilet stool system in a water closet. Since in 21st century water would be the prospected factor to measure the wealth of a country instead of the oil, water saving technologies in the toilet stool in a closet system is getting more important than the cleaning stool and the reducing noise performances. According to the statistics in Korea the percentage of using water in toilet is about 27% to the total amount of water used. Therefore, this study theoretically approached the possible amount of water saving and suggested the new variable position straight trap device in the toilet stool system.

• Journal of Aerospace System Engineering
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• v.12 no.1
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• pp.17-26
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• 2018

The interaction model between variable-speed control moment gyros and a satellite has been studied based on the multi-body dynamics. Using the interaction model, we could obtain data for the design of VCMG motors and the strength design of structure. The interaction effects of flexible modules such as solar panels were included. Flexible modes are excited by the satellite's maneuver, and these modes cause perturbations in the satellite attitude. We developed a simulation program by Modelica and verified the proposed model.