COMPATIBILITY OF SYSTEMS OF FUZZY RELATION EQUATIONS

In this paper, a fuzzy relation equation system with the generalized conjunction and implication operations is considered. Necessary and sufficient conditions of solvability of this system are proved. The case where these conditions are not fulfilled is considered and the solvability degree of the approximate solution is estimated. The interpolation property of the solution independently on whether it is precise or approximate is established.     

基于加权最小绝对值的大电力系统潮流可行解优化恢复方法

电力系统基本潮流无可行解时,通常只能根据经验以人工对可调的负荷出力进行反复调试才能获得一个较接近初始状态的新可行解。为了在恢复潮流可行解的同时,找到原运行方式中导致无解的症结,以节点注入偏差量绝对值最小为目标,提出了一种新的潮流恢复实用模型,并采用原—对偶内点法求解。对IEEE标准系统及实际超大电网系统的仿真表明该模型有效,优化结果可以较好地辨识出导致原运行方式无潮流可行解的节点出力和负荷,计算效率已达到实际应用水平。     

Electrochemical behavior of Cu(Ⅱ) reduced in CH3OH and DMSO

The cyclic voltammetry and the potential-time curve after galvanostatic electrolysis were used to study the electrode processes of Cu(Ⅱ) in CH3OH solution and DMSO solution. The electroreduction of Cu(Ⅱ) to Cu on a Pt electrode proceeds in two steps: Cu(Ⅱ) + e = Cu(Ⅰ); Cu(Ⅰ) + e = Cu. The reduction potential of Cu(Ⅱ) in DMSO solution is more negative than that in CH3OH solution, and the diffusion coefficient of Cu(Ⅱ) ion in DMSO solution is larger than that in CH3OH solution because the polarity of DMSO is larger than that of CH3OH observably and has a stronger solvating power.     

The Lyapunov exponent and joint spectral radius of pairs of matrices are hard—when not impossible—to compute and to approximate

We analyze the computability and the complexity of various definitions of spectral radii for sets of matrices. We show that the joint and generalized spectral radii of two integer matrices are not approximable in polynomial time, and that two related quantities—the lower spectral radius and the largest Lyapunov exponent—are not algorithmically approximable.This work was completed while Blondel was visiting Tsitsiklis at MIT. This research was supported by the ARO under Grant DAAL-03-92-G-0115.     

Existence and uniqueness of solutions for DC networks containing non‐linear ideal op amps

In this paper we are concerned with networks obtained by connecting independent sources, linear resistors and non‐linear ideal op amps. A necessary and sufficient condition for the existence and uniqueness of solutions for every positive output saturation voltage of the op amps and every value of the independent sources is found. Copyright © 2001 John Wiley & Sons, Ltd.     

一种改进的基于潮流定解拓扑可观测性分析方法

针对现有基于潮流定解的拓扑可观测性分析方法中存在的两类漏判问题,依据量测岛内未知状态量至多只有一个复电压的基本原理,以有注入量测的边界节点邻接表为对象,提出可解决两类漏判问题的系统化可观测性分析方法。该方法结合方程组局部可解的判定思想和启发式搜索算法,给出待并网虽整体不可合并但局部可合并的判别方法;通过分析存在交集的待并网可组合判断的必要条件,解决两个待并网潮流分别不可解而组合可解的判别问题。最后以15节点算例系统和一个实际电网算例验证了所提算法的有效性。     

非线性积分方程的正概周期解

一类具有概周期的时滞非线性积分方程具有正概周期解。     

Study on the closed-loop properties of GPC

Based on the coefficient mapping of eigenpolynomial from plant to GPC closed-loop system in the IMC structure, the solvability of the optimal control law of GPC and some properties of GPC in relationship with tun ing parameters are discussed Theorems on GPC resulting in deadbeat control are given by properly choosing the design parameters. Furthermore, new result about reducing GPC closed-loop system is derived, which extends the former conclusions. It also provides a new way to study the properties of GPC system based on coefficient mapping     

Output regulation of discrete‐time linear plants subject to state and input constraints

Discrete‐time output regulation of linear systems with state and/or input constraints on magnitude is considered. Structural properties of linear plants are identified under which the so‐called constrained semi‐global and global output regulation problems are solvable. As in the case of continuous‐time systems, an important aspect of our development is a taxonomy of constraints showing a clear relationship between the constraint types and the output regulation results. Solvability conditions are developed for semi‐global and global output regulation problems. Appropriate regulators are constructed for problems that are solvable. Copyright © 2003 John Wiley & Sons, Ltd.     

Semi‐global stabilization of discrete‐time systems subject to non‐right invertible constraints

This paper investigates time‐invariant linear systems subject to input and state constraints. We study discrete‐time systems with full or partial constraints on both input and state. It has been shown earlier that the solvability conditions of stabilization problems are closely related to important concepts such as the right invertibility or non‐right invertibility of the constraints, the location of constraint invariant zeros, and the order of constraint infinite zeros. In this paper, for general time‐invariant linear systems with non‐right invertible constraints, necessary and sufficient conditions are developed under which semi‐global stabilization in the admissible set can be achieved by state feedback. Sufficient conditions are also developed for such a stabilization in the case where measurement feedback is used. Such sufficient conditions are almost necessary. Controllers for both state feedback and measurement feedback are constructed as well. Copyright © 2009 John Wiley & Sons, Ltd.