• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.352-355
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• 1995

In this paper, estimation error bounds of the optimal FIR (Finite Impulse Response) filter, which is proposed by Kwon et al.[1, 2], are presented in discrete-time systems with the model uncertainty. Performance bounds are here represented by the upper bounds on the difference of the estimation error covariances between the nominal and real values in case of the systems with the noise or model parameter uncertainty. The estimation error bounds of the discrete-time optimal FIR filter is compared with those of the Kalman filter via a numerical example applied to the simulation problem by Toda and Patel[3]. Simulation results show that the former has robuster performance than the latter.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.104.4-104
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• 2001

This paper addresses a supervisory control problem to meet bounded time constraints in real-time nondeterministic discrete event systems (DESs) represented as timed transition models. For a timed language specification representing a bounded time constraint, this paper introduces the notions of trace-controllability and time-controllability. Based on the notions, this paper presents the necessary and sufficient conditions for the existence of a supervisor for a real-time nondeterministic DES to achieve the specification.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.4
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• pp.396-399
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• 2009

This paper presents the notion of time-coobservability as a core condition far the existence of a decentralized supervisor achieving a given language specification in a timed discrete event system (TDES). A TDES is modeled by the framework of Brandin & Wonham [5], and the decentralized supervisory control architecture presented is extended from the untimed architecture of Yoo & Lafortune [1]. To develop the time-coobservability of a language specification, specifically this paper presents the C&P time-coobservability and D&A time-coobservability in the consideration of the event tick and forcing mechanism of decentralized supervisors.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.3
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• pp.158-164
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• 1996

In this paper, we consider the problem of robust stability of discretd time-delay systems subjected to perturbations. Two classes of perturbations are treated. The first one is the nonlinear norm-bounded perturbation, and the second is the structured time-varying parametric perturbation. Based on the discrete-time Lyapunov stability theory, several new sufficient conditions for robust stability of the system are presented. From these conditions, we can estimate the maximum allowable bounds of the perturbations which guarantee the stability. Finally, numerical examples are given to demonstrate the effectiveness of the results.

• 전기의세계
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• v.29 no.11
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• pp.742-750
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• 1980

The problem of nonlinear time-invariant system identification by estimation of Wiener kernels is studied for discrete time systems with inputs having symmetric probability distributions. G-functionals are constructed. It is further shown that under idealized conditions, these seemingly different techniques yield the same results. The results of identification of asimulated second degree system is presented.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.10
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• pp.856-860
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• 2002

The guaranteed stability margin of LQ optimal regulators with cross-product terms in a performance index is derived for the discrete-time case. In order to obtain the guaranteed stability margin, the singular value of the return difference matrix is examined. A numerical simulation is provided to demonstrate the validity of the derived stability margin.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.23-23
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• 2000

In this paper, we proposed the problems of robust stability and 개bust H$_{\infty}$ control of discrete time-delay linear st.stems with Frobenius norm-bounded uncertainties. The existence condition and the design method of robust H$_{\infty}$ state feedback control]or are given. Through some changes of variables and Schur complement, the obtained sufficient condition can be rewritten as an LMI(linear matrix inequality) form in terms of all variables.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.5
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• pp.11-16
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• 1998

DS/CDMA systems for the high speed communication require high code rats. In discrete time CDMA receivers, the performance degradation, caused by the phase difference between transmission code and reference code, increase the sampling frquency of the receiver. This increment of the sampling frequency makes hard to implement high speed CDMA systems. This paper analyzes the SIR(signal to interference Ratio) performance of the discrete time DS/CDMA system, based on the code phase difference. The results of this paper may be useful to study a low-sampling CDMA receiver.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.71-80
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• 2008

In this study, a simulation framework, which can support developing various simulation systems for the improvement of process planning in shipbuilding such as the block erection, the block turn-over, and so on, is proposed. In addition, a simulation kernel, which is a key component of the simulation framework, is implemented according to the concept of the combined discrete event and discrete time simulation. To evaluate the efficiency and applicability of the proposed simulation framework, it is applied to the block erection process in shipbuilding. The result shows that the proposed simulation framework can provide the consistent, integrated development environment for a simulation system, as compared with existing studies and commercial simulation systems.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.3
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• pp.363-368
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• 2004

In this paper, the robustness property of 2nd-order iterative learning control(ILC) method for a class of linear and nonlinear discrete-time dynamic systems is studied. 2nd-order ILC method has the PD-type learning algorithm based on both time-domain performance and iteration-domain performance. It is proved that the 2nd-order ILC method has robustness in the presence of state disturbances, measurement noise and initial state error. In the absence of state disturbances, measurement noise and initialization error, the convergence of the 2nd-order ILC algorithm is guaranteed. A numerical example is given to show the robustness and convergence property according to the learning parameters.