• Earthquakes and Structures
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• 제23권2호
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• pp.207-219
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• 2022

Seismic response control has always been a grave concern with the damage and collapse of many buildings during the past earthquakes. While there are several existing techniques like base isolation, viscous damper, moment-resisting beam-column connections, tuned mass damper, etc., many of these are succumbing to either of large displacement, near-fault, and long-period earthquakes. Keeping this viewpoint, extensive research on the application of smart materials for seismic response control of buildings was attempted during the last decade. Shape Memory Alloy (SMA) with its unique properties of superelasticity and shape memory effect is one of the smart materials used for seismic control of buildings. In this paper, an exhaustive review has been compiled on the seismic control applications of SMA in buildings. Unique properties of SMA are discussed in detail and different phases of SMA along with crystal characteristics are illustrated. Consequently, various seismic control applications of SMA are discussed in terms of performance and compared with prevalent base isolators, bracings, beam-column connections, and tuned mass damper systems.

• 조명전기설비학회논문지
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• 제19권1호
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• pp.175-181
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• 2005

본 논문에서는 자동화 시스템의 고속 정밀 제어를 위한 퍼지-PLL 제어기를 제안한다. 기존의 PLL 제어기는 넓은 데드존 때문에 지터 잡음을 발생하고, 긴 지연시간 때문에 고속 동작의 정밀제어에는 부적합 하다. 본 논문에서는 이러한 문제를 해결하기 위하여, 제어영역을 고속 제어와 정밀제어 영역으로 구분한다. 먼저 퍼지 제어 기법을 적용하여 신속한 과도응답을 수행하고, 오차가 설정된 범위에 진입하면 새로운 위상 주파수 검출기를 설계한 PLL 제어기를 사용하여 정밀제어를 수행한다. 제안된 다중 구조의 위상 주파수 검출기는 데드존과 지터 잡음을 개선하고, 상승 에지에서 동작하는 P-PFD와 하강 에지에서 동작하는 N-PFD로 구성하여 PLL의 응답 특성을 향상 시킨다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.508-512
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• 1989

A new control law of a VSCS is illustrated and put into an analytical form. Using the presented control law, a VSCS shows smooth response, low control input and high accuracy in comparison with those by typical control law.

• Structural Engineering and Mechanics
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• 제15권2호
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• pp.239-248
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• 2003

The dynamic response analysis of closed loop control system based on probability for the intelligent truss structures with random parameters is presented. The expressions of numerical characteristics of structural dynamic response of closed loop control system are derived by means of the mode superposition method, in which the randomness of physical parameters of structural materials, geometric dimensions of active bars and passive bars, applied loads and control forces are considered simultaneously. The influences of the randomness of them on structural dynamic response are inspected by several engineering examples and some significant conclusions are obtained.

• Structural Engineering and Mechanics
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• 제24권3호
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• pp.375-393
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• 2006

Under high velocity, pulse type near source earthquakes semi-active control systems are very effective in reducing seismic response base isolated structures. Semi-active control systems can be classified as: 1) independently variable stiffness, 2) independently variable damping, and 3) combined variable stiffness and damping systems. Several researchers have studied the effectiveness of independently varying damping systems for seismic response reduction of base isolated structures. In this study effectiveness of a combined system consisting of a semi-active independently variable stiffness (SAIVS) device and a magnetorheological (MR) damper in reducing seismic response of base isolated structures is analytically investigated. The SAIVS device can vary the stiffness, and hence the period, of the isolation system; whereas, the MR damper enhances the energy dissipation characteristics of the isolation system. Two separate control algorithms, i.e., a nonlinear tangential stiffness moving average control algorithm for smooth switching of the SAIVS device and a Lyapunov based control algorithm for damping variation of MR damper, are developed. Single and multi degree of freedom systems consisting of sliding base isolation system and both the SAIVS device and MR damper are considered. Results are presented in the form of nonlinear response spectra, and effectiveness of combined variable stiffness and variable damping system in reducing seismic response of sliding base isolated structures is evaluated. It is shown that the combined variable stiffness and variable damping system leads to significant response reduction over cases with variable stiffness or variable damping systems acting independently, over a broad period range.

• 제어로봇시스템학회논문지
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• 제5권6호
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• pp.744-752
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• 1999

In this paper, we studied the response characteristics of $\alpha$, $\beta$ separated type, combined type, PI typed, and feedforward type in 2DOF-PID controller through the simulation and the experiments designed with the multivariable flow control system. The parameters $\alpha$ and $\beta$ give an affect to characteristics of controller in separated type but $\gamma$ does not give an affect to the characteristics of 2-DOF PID. The more $\beta$ increases, the more overshoot decreases and especially, in case of PI type represent clearly. The $\alpha$, $\beta$ separated type has a very small overshoot and its magnitudes in 2-DOF PID onctroller increases in order of $\alpha$, $\beta$ combined type, PI type, feedforward type, conventional type. The response characteristics of simulation are similar to that of experiments but the experimental characteristics in the multivariable flow control system has the delayed response. The time delay of response in experiments depends on 2-DOF parameter $\alpha$, $\beta$, $\gamma$ and the overshoot increase as the $\alpha$, $\beta$, $\gamma$ increase. So, we can have a satisfactory response by tuning D gain.

• 대한한방소아과학회지
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• 제21권1호
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• pp.189-209
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• 2007

Objectives : In order to study the effect of Dangkwiyughwangtang and Okbyoungpoongsangamibang on the immune response induced by methotrexate in mice. Method : Delayed type of hypersensitivity, hemagglutinin titer, hemolysin titer, rosette forming cells, phagocytic activity for immune response, lymphocyte transformation, and productivity of Interleukin-2 were measured. Results : Body weight decreasing was significantly inhibited as compared with control group in both the Dangkwiyughwangtang and Okbyoungpoongsangamibang groups. Delayed type of hypersensitivity was significantly increased as compared with control group in both groups Hemagglutinin titer was significantly increased as compared with control group in both groups. Hemolysin titer was significantly increased as compared with control group in the Okbyoungpoongsangamibang group. Rosette forming cells were significantly increased as compared with control group in both groups. Phagocytic activity for immune response was slightly decreased in the Dangkwiyughwangtang group and slightly increased in the Okbyoungpoongsangamibang group insignificantly as compared with the control group. Lymphocyte transformation was significantly increased as compared with the control group in both the Dangkwiyughwangtang and Okbyoungpoongsangamibang groups. Productivity of Interleukin-2 was significantly increased as compared with the control group in both the Dangkwiyughwangtang and Okbyoungpoongsangamibang groups. Conclusion : Both the Dangkwiyughwangtang and Okbyoungpoongsangamibang groups enhance immunity in mice.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.331-334
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• 1996

It is a well-known problem that the adaptive control has a poor transient response. In order to improve this problem, the scheme that model-reference adaptive control (MRAC) uses the genetic algorithm (GA) in the search for parameters is proposed. Use genetic algorithm (GA) in the searching for controller's parameters set and conventional gradient method for fine tuning. And show the reduction of the oscillations in transient response comparing with the conventional MRAC.

• 문화기술의 융합
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• 제6권1호
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• pp.43-53
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• 2020

이 연구에서 우리는 아파트 세대 내에 화재발생 시 대피요령에 따른 화재의 불안요인을 낮추며 관리사무소의 관리역량이 안전의식 및 화재대응에 미치는 영향력에 대한 조절효과를 분석하였다. 연구결과는 첫째, 아파트 거주자의 안전의식 및 관리주체의 인식이 화재대응성과에 정(+)의 영향을 미치는 것으로 나타났다. 이는 아파트 거주자의 안전의식 및 관리주체의 인식수준이 높을수록 화재대응성과도 높아짐을 알 수 있다. 둘째, 관리사무소의 관리역량 수준이 높을수록 안전의식 및 관리주체의 인식이 화재대응성과에 정(+)의 영향을 미치는 것으로 나타났다. 이러한 결과는 관리사무소장의 리더십이 높을수록 아파트 거주자의 주거만족도도 높은 경향을 보이고 거주자와의 소통하는 자세가 높을수록 화재대응성과에도 긍정적인 영향이 있음을 의미한다. 마지막으로, 관리사무소 관리역량은 아파트거주자의 안전의식 및 관리주체의 인식수준이 화재대응성과에 미치는 영향을 조절하는 효과가 있는 것으로 분석되었다. 이러한 결과는 모형의 R² 값의 변화량이 1단계보다 2단계가 증가하였고 3단계에서는 조절변수의 상호작용 항을 추가함에 따라 단계적으로 증가하였다. 따라서 조절변수인 관리사무소 관리역량은 아파트거주자의 안전의식 및 관리주체의 인식수준이 화재대응성과에 미치는 영향을 조절하는 효과가 있는 것으로 분석되었다.

• 항공우주시스템공학회지
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• 제9권1호
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• pp.12-18
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• 2015

The inter-conversion between different control laws in flight has a lot of risk. The SWM(Switching Mechanism) including logic and stand-by mode is designed to analyze the transient response of aircraft during inter-conversion between different control laws, based on the in-house software for non-real-time and real-time simulation. The SWM applies the fader logic of TFS(Transient Free Switch) to minimize the transient response of an aircraft during the inter-conversion, and applies the reset '0' type of the stand-by mode to prevent surface saturation due to integrator effect in the disengaged flight control law. The transition time is also important to minimize the objectionable transient response in the inter-conversion, as well as the transition control law design. This paper addresses the results of non-real-time simulation for the characteristics of transient response to different transition time to select the adequate transient time, and the real-time pilot evaluation, using SSWM(Software Switching Mechanism) and HSWM(Hardware Switching Mechanism), which is met for Level 1 flying qualities and assures safety of flight.