• Journal of the Korean Geosynthetics Society
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• v.2 no.3
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• pp.3-9
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• 2003

Geosynthetics as a reinforcing material for earth structures have ever increased due to their excellent economy, fine external appearance, and easy construction. Geogrids are high-strength, orientated-polymer grid structures used to reinforce soil. This paper deals with the construction and sire monitoring for a 5.1m high-reinforcd slope with $75^{\circ}$ steep. The purpose of site monitoring is to evaluate the applicability of reforced slope with geogrid. Full scale field performance during and after construction was monitored by incorporating instrumentation including strain gauges on the geogrid, and horizontal and vertical movements.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.45-51
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• 2003

This paper presents a method to improve lateral stability of a four-seat canard aircraft, Velocity-173. Longitudinal stability of Velocity-173 is rather good, but lateral stability is relatively poor. A small panel which increases the area of vertical tail is designed and manufactured. In a design process, AAA(Advanced Aircraft Analysis) is used to predict the change in stability. Flight test is performed to validate the effect of a small panel attached under the vertical panel. Maximum likelihood estimation method is used to extract lateral controllability / stability derivatives from flight test data. This work validates the effect of a small panel attached under the vertical tail.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.230-234
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• 2007

이동 애드 혹 망에서 안정된 멀티캐스트 데이터 전달 구조는 데이터 전송률을 높이고 제어 부하를 맞추는데 기여한다. 이동 애드 혹 망의 동적 위상 때문에 애드 혹 환경에서 안정된 멀티캐스트 데이터 전달구조를 구성하는 것은 어려운 문제이다. 이 논문에서 우리는 이동 애드 혹 망을 위한 안정된 응용 계층 멀티캐스트를 제안한다. 이 프로토콜에서는 각각의 멤버 노드가 잔여 에너지와 지역 이동성에 따라 자신의 안정성을 미리 계산한다. 소스가 데이터 패킷을 전송해야 할 때, 변형된 지연 전달 방안을 통해 소스기반 오버레이 멀티캐스트 트리를 만든다. 오버레이 구성은 각각의 멤버 노드의 안정성에 따른다. 상대적으로 높은 안정성을 가진 멤버 노드는 하위 트리들을 가질 확률을 높여준다. 제안한 설계는 불안정한 멤버 노드들을 멀티캐스트 트리의 가장자리로 밀어내어 멀티캐스트 라우팅 안정성을 개선한다. 시뮬레이션 결과는 우리의 설계가 패킷 전송률, 링크 단절에 의한 손실률, 제어 부하 면에서 ODOMP[1]에 비해 우수하다는 것을 보여준다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.3
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• pp.79-90
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• 2004

Systematical robust stability analysis and design scheme for the feedback linearization control systems via fuzzy modeling are proposed. It is considered that uncertainty and disturbances are included in the Takagi-Sugeno fuzzy models representing the nonlinear plants. Robust stability of the closed system is analyzed by casting the systems into the diagonal norm bounded linear differential inclusions and by converting the analysis and design problems into the linear matrix inequality optimization, a numerical method for finding the maximum stable ranges of the fuzzy feedback linearization control gains is also proposed. To verify the effectiveness of the proposed scheme, the robust stability analysis and control design examples are given.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.303-303
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• 2020

국내의 주요 외곽시설은 대수심화 및 설계외력의 증대 등으로 경제성 및 안정성 등의 확보를 위해 혼성제 형식의 구조물을 적용하는 사례가 주를 이루고 있다. 혼성제 근고부 안정성과 관련해서는, 설계파에 대한 안정적인 피복재 중량을 구하는 것이 설계상 중요하다. 기존의 직각 입사파에 대한 연구는 많이 수행되어 왔으나, 경사 입사파 조건에 대한 검토 사례는 미미한 실정이다. 또한 직각입사 뿐만 아니라 경사 입사파에 대한 근고부 중량산정식으로 확장된 Tanimoto식을 적용하고 있으나, 수리실험과 중량산정식에 대한 오차가 발생하고 있어 수리실험을 통해 기존의 산정식에 대한 검토가 필요하다. 따라서 본 연구에서는 경사입사파 조건에 따른 혼성제 제두부 구간의 피복재 안정성에 대하여 실험을 수행하였다. 설치수심은 0.3m 수심으로 고정하고, 입사각도를 0°, 30°, 45°, 60° 및 75°로 변화시켜 실험을 수행하였다. 전체 연장 10m의 모형에서 종점부 1m 구간을 실험구간으로 설정하고, 피복재의 종류는 피복석(50g), 콘크리트 피복블록(Tetrapod, Tripod)를 사용하였으며, 파랑조건은 불규칙파를 적용하였다. 주기 및 파고를 변화시켜 수리실험을 수행하였다. 실험결과는 제두부 구간에 피복된 피복재의 구간별 피해율을 분석하기 위해 구역분할도 적용하였으며, 확장된 Tanimoto식과 비교분석하여 중량산정식의 타당성을 검토하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.8-12
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• 2005

This paper designed electronic ballast inverter circuit using the PSpice simulation and it compared with practical ballast about electrical characteristics. Used electronic ballast driving type is self-exciting half bridge inverter we have got much the same electrical result both simulation and experiment of practical electronic ballast.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.23-29
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• 1995

There are many articles about the HID lamps about it's characteristics and simulation methods for lamp design or ballast design. For the electronic ballasts of HID lamps, There are some problems caused by acoustic-resonance which destabilizes the arc of HID lamps. So, some studies suggest the methods to avoid it. For example, the methods suggested are high frequence driving over 100[kHz], and mixed frequence driving which alternates high frequence and low frequence, and squarewave driving etc. This study suggests the electronic ballast of HID lamps that solves the problems of acoustic-resonance, and can control the luminance by constant current boostes chopper of which frequence is 30[kHz] and by the squarewave driving of which frequence is 55.5[Hz.] As follows, we have the good electronic ballast for HID lamps which has the characteristics of a light weight, and a function of luminance control and a high quality luminosity and which saves electrical energy.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.4
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• pp.59-65
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• 1997

This paper proposes a new approach for the design of a multi-output electronic ballast for fluorescent lamps of different outputs and control method. At first, a standard-output electronic ballast is constructed and then fluorescent lamps with different outputs are lighted by the frequency control of inverter circuit using MeV. This multi-output electronic ballast consists of a rectifier circuit, an inverter circuit, and a frequency control circuit to determine the optimal frequency for the lamps of different output. In order to verify the proposed design method, a prototype of a multi-output electronic ballast for 11 [WJ. 15[WJ compact fluorescent lamps and 20W fluorescent lamp is constructed. Results of observing the voltage and current characteristics of lamps are in accord with those of PSpice simulation. Also its efficacy is nearly the same as the other electronic ballasts. From the result, therefore, validity of the proposed design method of a multi-output electronic ballast for fluorescent lamps is verified.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.149-156
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• 2011

Considerable evaluation is needed to design a new longitudinal tunnel in advance because it damaged drivers' driving safety and heightened the possibility of traffic accidents with its physical characteristics. Specifically, considering traffic psychological and ergonomic factors was very important to prevent the difficulty of maintaining safe speed, the increase of the drowsy driving, the fatality of traffic accidents, and subjective feelings such as anxiety while driving a car through the tunnel, from design to construction. This study dealt with driving safety evaluation of an original road alignment design for the longitudinal tunnel (length: above 10km) with a driving simulator, and helped us to improve an original road alignment design and make an alternative road alignment design with presenting risky districts. The results of experiment showed that inflection points were revealed more risky districts, because they impaired driving safety and elevated driver workload while driving a car through around the inflection points of two-way route. Finally, the limitations and implications of this study were discussed.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.3
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• pp.337-342
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• 2009

This paper concerns delay-range-dependent robust stability and stabilization for time-delay nonliner system via T-S fuzzy model approach. The time delay is assumed to be a time-varying continuous function belonging to a given range. On the basis of a novel Lyapunov-Krasovskii functional, which includes the information of the range, delay-range-dependent stability criteria are established in terms of linear matrix inequality. It is shown that the new criteria can provide less conservative results than some existing ones. Moreover, the stability criteria are also used to design the stabilizing state-feedback controllers. Numerical examples are given to demonstrate the applicability of the proposed approach.