• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.87-89
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• 2005

This paper presents an optimal tuning method of the decentralized PI controller of the two-input, two-output(TITO) second order system with time-delay using LQR approach.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.54.6-54
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• 2002

1. Introduction 2. The Netwoked Control System Description 2.1 A close-loop system with the network induced delay 2.2 Discretization and State Augmentation of NCS 3. Delay-dependent H_infinity Controller Design for NCS 4. Numerical Example 5. Conclusion

• 한국정보처리학회논문지
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• 제6권7호
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• pp.1929-1940
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• 1999

본 논문은 TV 브라운관과 컴퓨터 모니터에 사용되는 마그네트(Magnet)에 일정한 자력을 갖도록 자화 시키는 착자기를 제어하며, 검사공정을 자동화하는 제어 시스템용의 집적회로를 설계하여 개발한 것에 관한 것으로써, 착자기의 콘트롤 모듈과 프로토콜 모듈의 주변기기 제어회로 부분을 0.8um CMOS SOG 기술로 설계하여 ETRI에서 공정하여 칩(Chip)을 완성시켜 동작을 확인하였다. 본 논문에서는 개별 셀(Single cell)의 지연 예측에 사용되었던 기존의 프로파게이션/램프 지연 모델(Propagation/ramp delay model)을 분석, 문제점을 보완 수정한 LODECAP(LOgic DEsign CAPture)의 인버터 선형 지연 모델을 응용하여 타이밍 콘트롤 블록 내의 지연 체인(Delay chain)을 설계 할 수 있는 새로운 "지연 예측 수식"을 제안하였다. 본 논문은 추출된 수식에 의거하여 타이밍 콘트롤 블록의 설계, 시스템에 적용하였으며, 나머지 블록들을 설계한 기법에 대하여도 상술하였다.여도 상술하였다.

• Smart Structures and Systems
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• 제14권6호
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• pp.1247-1267
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• 2014

Real-Time Hybrid Simulation (RTHS) is a novel approach conceived to evaluate dynamic responses of structures with parts of a structure physically tested and the remainder parts numerically modelled. In RTHS, delay estimation is often a precondition of compensation; nonetheless, system delay may vary during testing. Consequently, it is sometimes necessary to measure delay online. Along these lines, this paper proposes an online delay estimation method using least-squares algorithm based on a simplified physical system model, i.e., a pure delay multiplied by a gain reflecting amplitude errors of physical system control. Advantages and disadvantages of different delay estimation methods based on this simplified model are firstly discussed. Subsequently, it introduces the least-squares algorithm in order to render the estimator based on Taylor series more practical yet effective. As a result, relevant parameter choice results to be quite easy. Finally in order to verify performance of the proposed method, numerical simulations and RTHS with a buckling-restrained brace specimen are carried out. Relevant results show that the proposed technique is endowed with good convergence speed and accuracy, even when measurement noises and amplitude errors of actuator control are present.

• 대한임베디드공학회논문지
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• 제6권3호
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• pp.149-156
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• 2011

Transmission delay and packet loss induced by a communication network can degrade the control performance and, even make the system unstable. This paper presents a method for compensating transmission delay and packet loss in a networked control system for unmanned underwater vehicle. The proposed method is based on Lagrange interpolation in order to satisfy the requirements of simplicity and model-independency. In this work, the lost/delayed data are estimated in real time by only using the past data without requiring any mathematical model of the controlled system. Consequently, the proposed method can be implemented independent of the controlled system, and also it can achieve fast and accurate compensation performance. The performance of the proposed technique is evaluated by numerical simulations with an unmanned underwater vehicle.

• Structural Engineering and Mechanics
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• 제40권3호
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• pp.431-451
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• 2011

Time delay inevitably exists in active control systems, and it may cause the degradation of control efficiency or instability of the systems. So time delay needs to be compensated in control design in order to eliminate its negative effect on control efficiency. Today time delay in linear systems has been more studied and some treating methods had been worked out. However, there are few treating methods for time delay in nonlinear systems. In this paper, an active controller for a nonlinear and hysteretic building structure with time delay is studied. The nonlinear and hysteretic behavior of the system is illustrated by the Bouc-Wen model. By specific transformation and augmentation of state parameters, the motion equation of the system with explicit time delay is transformed into the standard state space representation without any explicit time delay. Then the fourth-order Runge-Kutta method and instantaneous optimal control method are applied to the controller design with time delay. Finally, numerical simulations and comparisons of an eight-story building using the proposed time-delay controller are carried out. Simulation results indicate that the control performance will deteriorate if time delay is not taken into account in the control design. The simulations also prove the proposed time delay controller in this paper can not only effectively compensate time delay to get better control effectiveness, but also work well with both small and large time delay problems.

• 대한전자공학회논문지SD
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• 제38권4호
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• pp.266-276
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• 2001

빠른 반도체 기술의 발전으로 인하여 VLSI 회로의 복잡도는 크게 증가하고 있다. 그래서 복잡한 회로를 테스팅하는 것은 아주 어려운 문제로 대두되고 있다. 또한 집적회로의 증가된 집적도로 인하여 여러 가지 형태의 고장이 발생하게 됨으로써 테스팅은 더욱 중요한 문제로 대두되고 있다. 이제까지 일반적으로 지연 고장 테스팅에 대한 신뢰도는 가정된 고장의 개수에 대한 검출된 고장의 개수로 표현되는 전통적인 고장 검출율로서 평가되었다. 그러나 기존의 교장 검출율은 고장 존재의 유무만을 고려한 것으로써 실제의 지연 고장 테스팅에 대한 신뢰도와는 거리가 있다. 지연 고장 테스팅은 고착 고장과는 달리 경로의 진행 지연과 지연 결함 크기 그리고 시스템 동작 클럭 주기에 의존하기 때문이다. 본 논문은 테스트 중인 경로의 진행 지연과 지연 결함 크기를 고려한 새로운 고장 검출율 메트릭으로서지연 결함 고장 검출율(delay defect fault coverage)을 제안하였으며, 지연 결함 고장 검출율과 결함 수준(defect level)과의 관계를 분석하였다.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.361-377
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• 2005

A mathematical model dealing with a prey-predator system with disease in the prey is considered. The functional response of the predator is governed by a Hoilling type-2 function. Mathematical analysis of the model regarding stability and persistence has been performed. The effect of delay and diffusion on the above system is studied. The role of diffusivity on stability and persistence criteria of the system has also been discussed.

• Journal of applied mathematics & informatics
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• 제29권5_6호
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• pp.1381-1393
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• 2011

In this paper, we consider two-species periodic Gilpin-Ayala competition system with delay and impulsive effect. By using some analysis methods, sufficient conditions for the permanence of the system are derived. Further, we give the conditions of the existence and global asymptotic stable of positive periodic solution.

• Journal of applied mathematics & informatics
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• 제23권1_2호
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• pp.385-395
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• 2007

The dynamics of a prey-predator system, where predator population has two stages, juvenile and adult with harvesting are modelled by a system of delay differential equation. Our analysis shows that, both the delay and harvesting effort may play a significant role on the stability of the system. Numerical simulations are given to illustrate the results.