• 한국정보처리학회논문지
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• 제4권4호
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• pp.1004-1012
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• 1997

본 논문은 1치 논리 시뮬레이션 환경에서 효율적인 헤저드 분석을 위한새로운 TRF( Transition Rise/Fall)지연모델을 제안한다. 주어진 회로에 있어서 헤저드 분석을 수행 하기 위해 우선 응답시간 지연과 천이시간 지연을 허용하는 5치 논리 시뮬레이터 에 의해서 타이밍 분석이 수행되고, 이미 수행된 타이밍 관계를 조사하므로써 헤저드 를 검출할 수 있다.몇 개의 예제회로에 대해서 시뮬레이션을 수행한 결과를 통하여 제안한 방법을 실용성을 입증하였다.

• Transactions on Control, Automation and Systems Engineering
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• 제2권3호
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• pp.149-156
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• 2000

Time delay observer (TDO), thanks to the time delay control (TDC) concept, requires little knowledge of a plant model, and hence is easy to design, robust to parameter variation and computationally efficient, yet can reconstruct states rather reliable for nonlinear plant. In this paper, we propose an improved version of TDO that solves two problems inherent in TDO as follows: TDO displays large reconstruction errors due to low-frequency uncertainty and has some restrictions on selecting its gains. By introducing a low pass filter and a state associated with it, we obtain an enhanced time delay observer (ETDO). This observer turns out to have smaller reconstruction errors than those of TDO and not to have any restriction on selecting its gains, thereby solving the problems. Through performance comparison by transfer function and simulation, we validate the analysis results of two observers (TDO and ETDO) and evaluate the performances. Finally, through experiments on BLDC motor system, the analysis results are clearly conformed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1955-1959
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• 2005

This paper presents a systematic analysis and a simple design of a robust adaptive control law for a class of non linear systems with modeling errors and a time-delay input. The theory for designing a robust adaptive control law based on input- output feedback linearization of non linear systems with uncertainties and a time-delay in the manipulated input by the approach of parameterized state feedback control is presented. The main advantage of this method is that the parameterized state feedback control law can effectively suppress the effect of the most parts of nonlinearities, including system uncertainties and time-delay input in the pp-coupling perturbation form and the relative order of non linear systems is not limited.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.239-242
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• 1998

Most of time delay existing in industrial processes can be modeled as an input time-delay which causes a lot of difficulties. To implement a time-delay free control, loop transfer function is recovered through the direct state feedback. For the proper state feedback, and observer is designed based upon the factorization approach which is known as one of the most powerful tool for the design of various control systems. The design scheme is parctically applied for the control of a DC motro which suffers from input time-delay. Simulational results demonstrate that this new algorithm guarantess the stability of the time-delayed system, as well as performance improvement compared to the conventional PI control.

• International Journal of Control, Automation, and Systems
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• 제6권2호
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• pp.263-268
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• 2008

An improved linear matrix inequality (LMI) representation of delay-independent $H_2$ performance analysis is introduced for linear delay systems with delays of any size. Based on this representation we propose a new $H_2$ memoryless state feedback design. By introducing a new matrix variable, the new LMI formulation enables us to parameterize memoryles s controllers without involving the Lyapunov variables in the formulations. By using a parameter-dependent Lyapunov function, this new representation proposed here provides us the results with less conservatism.

• 산업기술연구
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• 제23권A호
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• pp.41-46
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• 2003

Because the quality of a radio link in real environment is generally varied with time, there is a difference between the delay in the real environment and one obtained from the analytic model where a time-varying link model is not used as a link model for a Bluetooth. This paper analyzes the transmission delay of a message in the time-varying radio link model for the Bluetooth. The time-varying radio link is modeled with a two-state Markov model. The mean transmission delay of the message is analytically obtained in terms of the arrival rate of the message, the state transition probability in the Markov model, and the packet error rate.

• 대한수학회논문집
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• 제34권2호
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• pp.685-699
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• 2019

This research is focused on a continuous epidemic model of transmission of Plasmodium vivax malaria with a time delay. The model is represented as a system of ordinary differential equations with delay. There are two equilibria, which are the disease-free state and the endemic equilibrium, depending on the basic reproduction number, $R_0$, which is calculated and decreases with the time delay. Moreover, the disease-free equilibrium is locally asymptotically stable if $R_0<1$. If $R_0>1$, a unique endemic steady state exists and is locally stable. Furthermore, Hopf bifurcation is applied to determine the conditions for periodic solutions.

• Transactions on Control, Automation and Systems Engineering
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• 제4권3호
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• pp.195-198
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• 2002

In this note, we suggest a new matching condition and extend the stability analysis to the ultimate boundness of state $\chi$(t) for uncertain input-delay systems, using a sliding control with delay compensation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1744-1746
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• 2004

This paper focuses on the problem of asymptotic stabilization for time-delay systems. To this end, a memoryless state feedback controller is proposed. Then, based on the Lyapunov method, a delay-dependent stabilization criterion is devised by taking the relationship between the terms in the Leibniz-Newton formula into account. Certain free weighting matrices are used to express this relationship and linear matrix inequalities (LMIs)-based algorithm to design the controller stabilizing the system.

• Journal of Electrical Engineering and information Science
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• 제1권2호
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• pp.33-38
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• 1996

In this paper, we present a robust H\ulcorner control design method for parameter uncertain systems that have delay in both state and control input. Through a certain algebraic Riccati inequality approach, a state feedback controller is obtained. The proposed state feedback controller stabilizes parameter uncertain delay systems and guarantees disturbance attenuation within a prescribed level. An illustrative example is given to demonstrate the results of the proposed method.