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Liu P.-L.,Chienkuo Technical University
International Journal of Innovative Computing, Information and Control | Year: 2013

In this paper, the global asymptotic stability problem is dealt with for a class of recurrent neural networks (RNNs) with time-varying delays. The time delays are not necessarily differentiable and the uncertainties are assumed to be time-varying but norm-bounded. The activation functions are assumed to be neither monotonic, nor differentiable, nor bounded. By constructing the Lyapunov-Krasovskii functional and integral inequality approach, an improved delay-dependent stability criterion for delay RNNs is established in terms of linear matrix inequalities (LMIs). It is shown that the obtained criterion can provide less conservative results than some existing ones. Numerical examples are given to demonstrate the applicability of the proposed approach. © 2013 ICIC International.


Liu P.-L.,Chienkuo Technical University
International Journal of Innovative Computing, Information and Control | Year: 2013

This paper is concerned with the stability and stabilization for singular systems with time-varying delay. Firstly, by defining a novel Lyapunov function, a delay-dependent stability criterion, which ensures that the nominal unforced singular time-varying delay system is regular, impulse free and asymptotically stable, is established in terms of integral inequality approach (IIA) and linear matrix inequalities (LMIs). Then based on the obtained criteria, the exponential robust stability and stabilization problems are solved and the explicit expressions of the desired state feedback control laws are also given. Numerical examples are given to demonstrate the effectiveness and the benefits of the obtained results. © 2013 ICIC International.


Liu P.-L.,Chienkuo Technical University
ISA Transactions | Year: 2012

This paper is concerned with delay-dependent robust stability for uncertain systems with time-varying delays. The proposed method employs a suitable Lyapunov-Krasovskii's functional for new augmented system. Then, based on the Lyapunov method, a delay-dependent robust criterion is devised by taking the relationship between the terms in the Leibniz-Newton formula into account. By developing a delay decomposition approach, the information of the delayed plant states can be taken into full consideration, and new delay-dependent sufficient stability criteria are obtained in terms of linear matrix inequalities (LMIs) which can be easily solved by various optimization algorithms. Numerical examples are included to show that the proposed method is effective and can provide less conservative results. © 2012 ISA.


Chang K.-Y.,Chienkuo Technical University
International Journal of Hydrogen Energy | Year: 2011

This paper has presented a new approach to estimate the output voltage of proton exchange membrane fuel cell (PEMFC) accurately by combining the use of a genetic algorithm neural networks (GANN) model and the Taguchi method. Using the PEMFC experimental data measured from performance test equipment of PEMFC, the GANN model could be trained and constructed for obtaining the steady state output voltage of PEMFC. Furthermore, in order to determine the important parameters in GANN, the Taguchi method is used for parameter optimization, with the goal of reducing the estimation error. The test equipment of PEMFC is accurate enough for acquiring the output voltage of PEMFC, and is quite useful for teaching purpose. However, taking the high cost, complicated operation procedure and environment safety into consideration, it is necessary to develop a simulation model of PEMFC to benefit teaching and R&D. Therefore, this paper will present an approach for constructing a GANN model with precise accuracy for the output voltage of PEMFC. For achieving the GANN model with high precision, a troublesome work has to be taken care of, that is, to determine all the parameters required in GANN. We will introduce Taguchi method to solve this problem as well. Finally, to show the superiority of proposed model, this approach has compared the estimation values of output voltage for PEMFC from GANN and BPNN models without using Taguchi method. One can easily find that the error of the proposed method is much smaller than that of the GANN model without Taguchi method and of the BPNN model; that is, the proposed approach has better performance on estimation for PEMFC output voltages. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


This paper provides an improved delay-range-dependent stability criterion for linear systems with interval time-varying delays. No model transformation and no slack matrix variable are introduced. Furthermore, overly bounding for some cross term is avoided. The resulting criterion has advantages over some previous ones in that it involves fewer matrix variables but has less conservatism, which is established theoretically. Finally, two numerical examples are given to show the effectiveness of the proposed results. © 2013 ISA.Published by Elsevier Ltd. All rights reserved.


Liu P.-L.,Chienkuo Technical University
ISA Transactions | Year: 2014

In this paper, new conditions for the delay-range-dependent stability analysis of time-varying delay systems are proposed in a Lyapunov-Krasovskii framework. Time delay is considered to be time-varying and has lower and upper bounds. A new method is first presented for a system with two time delays, integral inequality approach (IIA) used to express relationships among terms of Leibniz-Newton formula. Constructing a novel Lyapunov-Krasovskii functional includes information belonging to a given range; new delay-range-dependent criterion is established in term of linear matrix inequality (LMI). The advantage of that criterion lies in its simplicity and less conservative. This paper also presents a new result of stability analysis for continuous systems with two additive time-variant components representing a general class of delay with strong application background in network-based control systems. Resulting criteria are then expressed in terms of convex optimization with LMI constraints, allowing for use of efficient solvers. Finally, three numerical examples show these methods reducing conservatism and improving maximal allowable delay. © 2013 ISA.


Liu P.-L.,Chienkuo Technical University
ISA Transactions | Year: 2013

In this paper, the problem of improved delay-dependent robust stability criteria for recurrent neural networks (RNNs) with time-varying delays is investigated. Combining the Lyapunov-Krasovskii functional with linear matrix inequality (LMI) techniques and integral inequality approach (IIA), delay-dependent robust stability conditions for RNNs with time-varying delay, expressed in terms of quadratic forms of state and LMI, are derived. The proposed methods contain the least numbers of computed variables while maintaining the effectiveness of the stability conditions. Both theoretical and numerical comparisons have been provided to show the effectiveness and efficiency of the present method. Numerical examples are included to show that the proposed method is effective and can provide less conservative results. © 2012 ISA.


Liu P.-L.,Chienkuo Technical University
ISA Transactions | Year: 2013

The robust asymptotic stability problem of genetic regulatory networks with time delays is investigated by Lyapunov functional approach and linear matrix inequality techniques (LMIs). Stability criteria for the delayed genetic regulatory networks are expressed as a set of LMIs, yielding much less conservative analytic results. New criteria with reduced conservatism are obtained and they involve less matrix parameters than the existing ones. Finally, three numerical examples are presented to illustrate effectiveness and less conservative results. © 2013 ISA.


This paper investigates a class of delayed cellular neural networks (DCNN) with time-varying delay. Based on the Lyapunov-Krasovski functional and integral inequality approach (IIA), a uniformly asymptotic stability criterion in terms of only one simple linear matrix inequality (LMI) is addressed, which guarantees stability for such time-varying delay systems. This LMI can be easily solved by convex optimization techniques. Unlike previous methods, the upper bound of the delay derivative is taken into consideration, even if larger than or equal to 1. It is proven that results obtained are less conservative than existing ones. Four numerical examples illustrate efficacy of the proposed methods. © 2013 ISA.Published by Elsevier Ltd. All rights reserved.


Liu P.-L.,Chienkuo Technical University
International Journal of Innovative Computing, Information and Control | Year: 2012

The problem of delay-dependent exponential stability is investigated for singular systems with state delay. In terms of linear matrix inequality (LMI) approach, some improved delay-dependent conditions are presented to ensure the considered system to be regular, impulse free and exponentially stable via an augmented Lyapunov functional and integral inequalities matrix. Numerical examples are given to illustrate the effectiveness and the benefits of the proposed methods. These results are shown to be less conservative than those reported in the literature. © 2012 ICIC International.

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