• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1982-1985
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• 2003

Future cellular networks will mainly be driven by, high quality channels, high band with utilization, low power consumption and efficient network management. For a given channel allocation, the capacity and quality of communication of cellular radio systems using CDMA(Code Division Multiple Access) can be increased by using a transmitter power control scheme to combat the near-far problem. Centralized power control schemes or distributed ones to maximize the minimum signal-to-interference in each user of CDMA wireless network have been investigated. This paper has proposed a distributed power control algorithm, which employs an adaptive search scheme, in order to solve quickly the linear systems of equations for power update in CDMA cellular radio systems. The simulation results show that the proposed scheme has faster convergence rate than the typical bang-bang type of distributed power control algorithm, which has been much used as a reference algorithm in IS-95A and W-CDMA communication network.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
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• pp.73-76
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• 2001

It is well-known that the convergence rate gets worse when an input signal to an adaptive filter is correlated. In this paper we propose a new adaptive filtering algorithm that makes the convergence rate highly improved even for highly correlated input signals. By introducing an orthogonal constraint between successive input signal vectors, we overcome the slow convergence problem caused by the correlated input signal. Simulation results show that the proposed algorithm yields highly improved convergence speed and excellent tracking capability under both time-invariant and time varying environments, while keeping both computation and implementation simple.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1-6
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• 2004

Lots of researches were gone already about grooving corrosion mechanism of ERW carbon steel pipe. But there is seldom study for water hammer happened by fluid and acceleration of corrosion rate by incresed flow velocity. Therefore, in this study carried out the analysis based on hydrodynamic and fracture mechanics. Analyzed stress that act on a pipe using ANSYS as a program, and also FLUENT and STAR-CD were used for flow phenomenon confirmation. As the result, fatigue failure is happened by water hammer and corrosion rate was increased because of turbulent flow.

• Journal of Pharmaceutical Investigation
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• 제24권4호
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• pp.227-231
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• 1994

The stability of red ginseng saponin in aqueous solution was studied with the acceleration test method. The degradation rate constant of ginsenoside Rb1, an index component of red ginseng saponin, was $2.371{\times}10^{-4}\;day^{-1}$ at $20^{\circ}C$, and the shelf-life was about 570 days. The pH-rate profile demonstrated that the most stable range was pH 6-8. Mannitol and benzyl alcohol, common excipients for injection, exerted no influence on the degradation reaction of ginsenoside Rb1.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.782-787
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• 2002

In optical disk drives (ODD), the demands of high data density and high speed have been increasing rapidly to achieve high data capacity and data transfer rate. The short wavelength laser, High NA objective lens, and high track following performance are needed to raise data density and data rate. For high-performance actuator, the improvement of linearity and acceleration become more important. Also, 3-axis actuator for active tilt compensation is introduced to overcome the decrease in disk tilt tolerance which is induced by short wavelength laser. In this paper, a hybrid type 3-axis actuator is presented and a new yoke structure, which can reduce the interaction between yoke and moving magnet, is designed to keep the efficiency of magnetic circuit. Experimental results show the validity of the yoke in the hybrid type actuator.

• 한국통신학회논문지
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• 제17권4호
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• pp.361-370
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• 1992

수직 이착륙기와 같은 비행체의 정지비행 도중 비행체의 위치각, 각속도, 각가속도와 같은 상태량을 궤환 시킨 SRFIMF(State Rate Feedback Implicit Model-Following)이론을 이용하여 4개의 팬을 갖는 부상제어시스템을 구성하였다. 이 부상제어시스템의 yaw제어를 행하여, 각 상태궤환이득 및 전향경로 이득을 변화시켜 부상제어시스템의 특정을 해석하였으며, 부상시스템과 같은 제어계에 SRFIMF방식을 적용시켜 그 타당성을 조사하였다.

• 대한화학회지
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• 제25권4호
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• pp.214-218
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• 1981

Solid인 Hexogen 존재하에서 hydroxyl-terminated polybutadiene과 isophorone diisocyanate의 혼성중합반응속도에 관하여 연구하였다. 중합반응속도는 Hexogen의 첨가량이 증가할 수록 빠르게 나타났지만, Hexogen의 촉매적 역할은 없었으며, 오직 entropy control에 의한 반응임을 밝혔다. 이 반응은 2차 반응속도법칙에 잘 일치하며, activation energy는 8.4 Kcal/mole로 거의 일정하다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.125.5-125
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• 2001

Until now, many guidance laws have been developed. They mainly used the classical tail-pursuit guidance method based on geometric angle information, the proportional navigation method based on the line of sight(LOS) rate, and the optimal guidance law based on optimal control theorem. In the augmented guidance law, target acceleration information and autopilot characteristics are added the guidance command. In this study, new guidance laws considering geometric angle are proposed. Two guidance laws are developed for the midcourse guidance law, and a guidance law is developed for the terminal guidance respectively. The proposed guidance laws utilize the LOS rate and the geometric angle information simultaneously. In the midcourse guidance, the guidance command is ...

• 대한전자공학회논문지SP
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• 제45권2호
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• pp.90-94
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• 2008

적응 필터의 입력 신호의 상관도 (correlation)가 클 경우 LMS 알고리즘의 수렴 속도는 상당히 느려지게 된다. 본 논문에서는 입력 신호의 상관도가 높은 상황에서 수렴 속도를 향상시킬 수 있는 적응 필터링 알고리즘을 제안한다. 입력 신호에 대하여 직교성을 가지도록 변환을 인위적으로 가하여 LMS 알고리즘의 한계를 극복한다. 제안한 알고리즘의 성능 향상은 시스템식별 모델을 통하여 그 수렴 속도의 개선을 확인하며 또한 시변 환경 하에서 적응 필터의 시변 추적 능력을 통해 보여 진다.

• Earthquakes and Structures
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• 제13권3호
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• pp.299-307
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• 2017

High Damping Rubber bearings (HDR bearings) have been used in the seismic design of bridge structures widely in China. In earthquakes, structural natural periods will be extended, seismic energy will be dissipated by this kind of bearing. Previously, cyclic loading method was used mainly for test studies on mechanical properties of HDR bearings, which cannot simulate real seismic responses. In this paper, Real-Time Substructure (RTS) test study on mechanical properties of HDR bearings was conducted and it was found that the loading rate effect was not negligible. Then the influence of peak acceleration of ground motion was studied. At last test results were compared with a numerical simulation in the OpenSees software framework with the Kikuchi model. It is found that the Kikuchi model can simulate real mechanical properties of HDR bearings in earthquakes accurately.