• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.806-811
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• 2017

This paper considers the delay-dependent stability of linear systems with a time-varying delay in the frame work of Lyapunov-Krasovskii functional(LKF) approach. In this approach, an integral inequality is essential to estimate the upper bound of time-derivative of LKF, and a less conservative one is needed to get a less conservative stability result. In this paper, based on free weighting matrices, an improved integral inequality encompassing well-known results is proposed and then a stability result in the form of linear matrix inequality is derived based on an augmented LKF. Finally, two well-known numerical examples are given to demonstrate the usefulness of the proposed result.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.170-182
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• 1999

In this paper, we present a tracking accuracy enhancement method by compensating the time delay of the video tracker in an EOTS. The proposed method has two functional parts, which can cope with the time delay of LOS and maneuvering target informations by Smith predictor and Kalman filter. So it can dramatically reduce the tracking error over conventional PI control or Smith predictor control. To verify the proposed method, various and extensive simulation and experimental results are given.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.2
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• pp.76-85
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• 1993

This paper describes the design of a technology-independent logic, function, and timing extraction system from SPICE-like network descriptions. Technology-independent extraction mechanism is provided in the form of technology files containing the rules for constructing logic gates and functional blocks. The designed system can be more effectively used in cell-based design by describing the cells to be extracted. Timing extraction is performed by using a linear RC gate delay model which takes interconnection delay into account. Experimental results show that estimated delay is within 10 percents for logic gate circuits when compared with SPICE. Through higher-level design descriptions obtained by extraction, design cycles can be considerably reduces.

• East Asian mathematical journal
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• v.32 no.3
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• pp.399-412
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• 2016

In this paper, we study the viscoelastic Kirchhoff type equation with the following nonlinear source and time-varying delay $$u_{tt}-M(x,t,{\parallel}{\nabla}u(t){\parallel}^2){\Delta}u+{\int_{0}^{t}}h(t-{\tau})div[a(x){\nabla}u({\tau})]d{\tau}\\+{\parallel}u{\parallel}^{\gamma}u+{\mu}_1u_t(x,t)+{\mu}_2u_t(x,t-s(t))=0.$$ Under the smallness condition with respect to Kirchhoff coefficient and the relaxation function and other assumptions, we prove the uniform decay rate of the Kirchhoff type energy.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.92-94
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• 2007

This paper considers an optimal control problem for a remote control to an electrical drive system with a DC motor. Since it is a linear control system with time-delay subject to unknown but bounded disturbance, we construct a worst-case feedback control policy. This policy can guarantee that, for all admissible uncertain disturbances, the real system state should be in a prescribed neighborhood of a desired value, and the cost functional takes the best guarantee value. The worst-case feedback control policy is allowed to be corrected at one correction point between the initial to the final time, which is equivalent to solving a 1-level min-max problem. Since the min-max problem at the stage does not yield a simple analytical solution, we consider an approximate control policy, which is equivalent and can be solved explicitly m the numerical experiments.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.1
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• pp.71-78
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• 2013

In highly reliable and durable systems, failures due to aging might result in catastrophes. Aging monitoring techniques to prevent catastrophes by predicting such a failure are required. Aging can be monitored by performing a delay test at faster clocks than functional clock in field and checking the current delay state from the test clock frequencies at which the delay test is passed or failed. In this paper, we focus on test clock control scheme for a system-on-chip (SoC) with multiple clock domains. We describe limitations of existing at-speed test clock control methods and present an on-chip faster-than-at-speed test clock control scheme for intra/inter-clock domain test. Experimental results show our simulation results and area analysis. With a simple control scheme, with low area overhead, and without any modification of scan architecture, the proposed method enables faster-than-at-speed test of SoCs with multiple clock domains.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.2
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• pp.151-156
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• 1998

This paper presents an $H_{\infty)$ output feedback controller design method for linear systems with delayed state, delayed control input, and delayed masurement output. Using a Lyapunov functional, the stability for delayed systems is discussed independently of delays. Also, sufficient condition for the existence of $H_{\infty)$ controllers of any order is given in terms of three linear matrix inequalities(LMIs). Based on positive definite solutions of their LMIs, we briefly explain the way to construct $H_{\infty)$ controller, which stabilizes time-delay systems independently of delays and guarantees an $H_{\infty)$norm bound.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.376-382
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• 2011

This paper proposes delay-dependent stability conditions of the fuzzy Markovian jumping Hopfield neural networks of neutral type with time-varying delays. By constructing a suitable Lyapunov-Krasovskii's (L-K) functional and utilizing Finsler's lemma, new delay-dependent stability criteria for the systems are established in terms of linear matrix inequalities (LMIs) which can be easily solved by various effective optimization algorithms. A numerical example is given to illustrate the effectiveness of the proposed methods.

• Nonlinear Functional Analysis and Applications
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• v.29 no.1
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• pp.179-195
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• 2024

In this article, we study the Picard-Ishikawa iterative method for approximating the fixed point of generalized α-Reich-Suzuki nonexpanisive mappings. The weak and strong convergence theorems of the considered method are established with mild assumptions. Numerical example is provided to illustrate the computational efficiency of the studied method. We apply our results to the solution of a nonlinear delay integral equation. The results in this article are improvements of well-known results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.1064-1073
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• 1999

In the integrated systems of wired and wireless networks, it is not fit to separate cellular networks to intelligent networks so IMT-2000 is basically developed including the intelligent networks. But it is not yet determined how functional entities of IMT-2000 map the corresponding physical entities. In this paper, we propose the integrated model by mapping various functional entities of IMT-2000 into the corresponding physical entities. Also, we proposs the call model for the mobile call setup and IN service call. Based on the proposed model, we evaluate the performance and compare with IMT-2000 in terms of the mean service delay and processing delay at each physical entities.