Distributed parameter modeling and finite-frequency loop-shaping of electromagnetic molding machine

We derive a mathematical model for an electromagnet inside a molding machine, and propose a novel loop-shaping method of the proportional–integral (PI) controller design for the system based on the generalized KYP (GKYP) lemma. The behavior of the molding machine is difficult to capture by using finite-dimensional models owing to eddy currents spatially distributed throughout the electromagnet. To analyze fundamental properties of the system both theoretically and experimentally, we first derive a mathematical model of the machine in terms of a partial differential equation (PDE). An analysis using the PDE model shows that a low-dimensional approximation performed by standard spatial discretization results in a spillover effect, which makes the behavior of the closed-loop system oscillatory. Then, to develop an easily tunable and implementable control system, we propose a novel loop-shaping method for PI control on the basis of the GKYP lemma. In this control system design, we use multiple low-dimensional models, which work simultaneously in specified finite frequency ranges. The proposed method successfully suppresses the spillover effect despite the use of low-dimensional approximants. Finally, we show the efficiency of the proposed control design method through numerical and experimental verification and discuss a performance limitation of the PI control.     

非正函数的积分极限定理

研究R<'n>上非正函数的积分极限定理.得出并证明了非正函数的列维定理、逐项积分定理、fatou引理,以及非正函数的L积分与R反常积分的相互关系定理.     

非线性项带导数的p-Laplacian边值问题解的存在性

研究了一类非线性项带高阶导数的p-Laplacian动力边值问题解的存在性;借助于推广形式的Mawhin连续引理,给出了边值问题解存在的充分条件.     

非线性H_∞控制的SOS设计

提出了一种新的非线性H∞控制的设计方法。虽然平方和(简称SOS)方法可用来求解不易用解析法求解的非线性问题,但还是不能直接来求解HJI不等式或非线性的有界实不等式。详细分析了SOS法在求解中的这些局限性。给出了求解非线性H∞控制的一种迭代设计的方法。每一次迭代分为两步。第一步是先用SOS法设计系统的非线性状态反馈,其增益阵是可调整的。第二步是求系统L2增益,用图解解析法求解计算中的优化问题。还给出了一个卫星大姿态机动的非线性H∞控制设计作为应用本方法的实例。     

基于Ward等值的多区域无功优化分解协调算法

针对多区域电力系统的无功优化问题,提出了基于Ward等值的分解协调算法.将所有子区域分为主区域和从区域,并确定边界节点在不同区域中的节点类型和区域间相角传递方法.在基态条件下,根据潮流计算结果确定边界节点等值注入功率初值.采用矩阵求逆辅助定理,提高优化过程中外部网络变压器变比变化引起的等值导纳矩阵计算效率问题,且大幅度提高了外部网络等值精度.引入适合无功优化算法的外部协调策略,以较少的协调通信量获得较好的协调效果.以IEEE 39节点和538节点实际系统为例,通过与集中优化方法进行比较,验证了该方法的有效性.     

Semantic and phonological activation in noun and pronoun production.

Speakers can refer to objects and other entities by nouns or pronouns. The present article investigated the production of gender-marked pronouns in German. Four picture-word interference experiments are reported, addressing 2 questions. First, is the lemma of a referent noun (i.e., the representation of the referent noun's semantic and syntactic properties) accessed when producing a pronoun? Second, if so, is this access confined to the lemma, or will the referent noun's phonological form be activated, too? The results suggest that in generating pronouns, speakers accessed the lemma of the referent noun, whereas its phonological form was not substantially activated. The results are discussed in the context of other recent experimental studies of pronoun and noun production. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Robust Regulator for Flexible-Joint Robots Using Integrator Backstepping

A robust regulator for flexible-joint robots is proposed, which yields constant torque disturbance rejection acting on the links. The design uses the integrator backstepping technique [4,5] to cancel nonlinearities and disturbance not in the range space of the control. Stability of the closed loop system is shown using iterative Liapunov functions.     

Using the incompressibility method to obtain local lemma results for Ramsey-type problems

We reveal a connection between the incompressibility method and the Lovász local lemma in the context of Ramsey theory. We obtain bounds by repeatedly encoding objects of interest and thereby compressing strings. The method is demonstrated on the example of van der Waerden numbers. In particular we reprove that . The method is applicable to obtain lower bounds of Ramsey numbers, large transitive subtournaments and other Ramsey phenomena as well.     

A Simplicial Approach for Discrete Fixed Point Theorems

We present a new discrete fixed point theorem based on a variation of the direction-preserving maps over simplicial structures. We show that the result is more general than the recent discrete fixed point theorem of Iimura et al. (J. Math. Econ. 41(8):1030–1036, [2005]) by deriving it from ours. The simplicial approach applied in the development of the new theorem reveals a clear structural comparison with the classical approach for the continuous case. X. Chen work was supported in part by the National Natural Science Foundation of China Grant (60553001), and the National Basic Research Program of China Grant (2007CB807900, 2007CB807901). X. Deng work supported by an SRG grant (No. 7001975) of City University of Hong Kong and an NNSFC grant (No. 60496327).     

线性多胞型不确定连续系统故障检测滤波器设计

The paper studies the problem of fault detection filter design for uncertain linear continuous-time systems. A design procedure dealing with parameter uncertainties is proposed for residual generation, the sensitivity to fault and the robustness against disturbances are both enhanced on residual outputs through satisfying some performance indexes. By the aid of the generalized Kalman-Yakubovich-Popov (GKYP) lemma, the fault sensitivity performance index can be dealt with in the given frequency range directly, which avoids approximations associated with frequency weights of the existing techniques. An iterative algorithm based on linear matrix inequality (LMI) is given to obtain the solutions. A numerical example is given to illustrate the effectiveness of the proposed methods.