Robust H∞ control of uncertain Markovian jump systems with time-delay

This correspondence is concerned with the robust stochastic stabilizability and robust H∞ disturbance attenuation for a class of uncertain linear systems with time delay and randomly jumping parameters The transition of the jumping parameters is governed by a finite-state Markov process. Sufficient conditionson the existence of a robust stochastic stabilizing and γ-suboptimal H∞ state-feedback controller are presented using the Lyapunov functional approach. It isshown that a robust stochastically stabilizing H∞ state-feedback controller can be constructed through the numerical solution of a set of coupled linear matrix inequalities. © 2000 IEEE.published_or_final_versio

A computational method for simultaneous LQ optimal control design via piecewise constant output feedback

This paper is concerned with simultaneous linear-quadratic (LQ) optimal control design for a set of LTI systems via piecewise constant output feedback. First, the discrete-time simultaneous LQ optimal control design problem is reduced to solving a set of coupled matrix inequalities and an iterative LMI algorithm is presented to compute the feedback gain. Then, simultaneous stabilization and simultaneous LQ optimal control design of a set of LTI continuous-time systems are considered via periodic piecewise constant feedback gain. It is shown that the design of a periodic piecewise constant feedback gain simultaneously minimizing a set of given continuous-time performance indexes can be reduced to that of a constant feedback gain minimizing a set of equivalent discrete-time performance indexes. Explicit formulas for computing the equivalent discrete-time systems and performance indexes are derived. Examples are used to demonstrate the effectiveness of the proposed method.published_or_final_versio

Simultaneous stabilization via static output feedback and state feedback

In this paper, the simultaneous stabilization problem is considered using the matrix inequality approach. Some necessary and sufficient conditions for simultaneous stabilizability of r strictly proper multi-input/multi-output (MIMO) plants via static output feedback and state feedback are obtained in the form of coupled ARI's. It is shown that any such stabilizing feedback gain is the solution of some coupled linear quadratic control problems where every cost functional has a suitable cross term. A heuristic iterative algorithm based on the linear matrix inequality (LMI) technique is presented to solve the coupled matrix inequalities. The effectiveness of the approach is illustrated by numerical example.published_or_final_versio

Necessary and sufficient conditions for stable H∞ stabilizability

In this paper, the stable H∞ control problem is addressed. It is shown that the stable H∞ control problem is reduced to finding a unimodular matrix such that a two block H∞ optimization problem is solvable. And then it can be solved if an unimodular matrix is selected such that a Nehari problem is solvable. In fact, if the unimodular matrix is selected as a constant matrix, then a previous result is obtained.published_or_final_versio

Combined Effect of Vorinostat and Grape Seed Proanthocyanidins on Modulation of Thymidine Phosphorylase in Non-Small Cell Lung Cancer

Purpose: To demonstrate the effect of histone deacetylase-inhibitor, vorinostat, on antitumour activity of grape seed proanthocyanidins (GSPs) in non-small cell lung cancer (NSCLC) cells.Methods: Expression of thymidine phosphorlase (TP) and thymidylate synthase (TS) was measured by real-time PCR and western blotting. TP knockdown was performed using specific small interfering RNA. Antitumour activity of combination of vorinostat and GSPs was assessed according to Chou and Talay method and by evaluating apoptosis.Results: Vorinostat treatment led to a significant increase in TP expression but decrease in TS expression in NSCLC cells. In H157 cells, increase in the concentration of vorinostat from 0.34 to 0.4 μM increased TP expression 3- to 6-fold. In H1299 cells, there was 7-fold reduction of TS transcript and 30-fold increase of TP transcript at 48 h. Vorinostat, when used in combination with GSPs, resulted in a synergistic anti-proliferative effect and increased apoptotic cell death. However, cells with TP knockdown did not exhibit vorinostat- and GSPs-mediated anti-proliferative effect and apoptotic cell death.Conclusion: The combination of vorinostat and GSPs can be an effective and innovative antitumour therapy for the treatment of NSCLC.Keywords: Histone deacetylase-inhibitor, Synergism, Apoptosis, Antitumo

A linear matrix inequality (LMI) approach to robust H2 sampled-data control for linear uncertain systems

In this paper, we consider the H2 sampled-data control for uncertain linear systems by the impulse response interpretation of the H2 norm. Two H2 measures for sampled-data systems are considered. The robust optimal control procedures subject to these two H2 criteria are proposed. The development is primarily concerned with a multirate treatment in which a periodic time-varying robust optimal control for uncertain linear systems is presented. To facilitate multirate control design, a new result of stability of hybrid system is established. Moreover, the single-rate case is also obtained as a special case. The sampling period is explicitly involved in the result which is superior to traditional methods. The solution procedures proposed in this paper are formulated as an optimization problem subject to linear matrix inequalities. Finally, we present a numerical example to demonstrate the proposed techniques.published_or_final_versio

Effect of iron loading on isolated rat myocardium

2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Hydrogen peroxide augments the injury effect of iron on the isolated rat heart and cardiomyocytes

2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe