This note concerns the problem of the robust stability of a linear system with a time-varying delay and polytopic-type uncertainties. In order to construct a parameter-dependent Lyapunov functional for the system, we first devised a new method of dealing with a time-delay system without uncertainties. In this method, the derivative terms of the state, which is in the derivative of the Lyapunov functional, are retained and some free weighting matrices are used to express the relationships among the system variables, and among the terms in the Leibniz-Newton formula. As a result, the Lyapunov matrices are not involved in any product terms of the system matrices in the derivative of the Lyapunov functional. This method is then easily extended to a system with polytopic-type uncertainties. Numerical examples demonstrate the validity of the proposed criteria.

A distributed computer energy management and control system (DCEMCS) has been established in a nonferrous metal smeltery. It consists of central computer system, local area computer system, real-time baseband local area network, and measurement and control mechanism. This paper presents the theory and techniques applied to the system design, espec-ially the hardware architecture and the main functions of DCEM CS, the hierarchical configu-ration and the dynamic coordination algorithm based on two level computers, the real-time local area network technique and the programming method, the distributed design technique for the applied software and the basic idea of designing and anaging the energy database.