Robust control for discrete-time singular large-scale systems with parameter uncertainty

This paper addresses the problem of robust stabilization for uncertain discrete-time singular large-scale systems with parameter uncertainties. The system under consideration is not necessarily regular. The parameter uncertainties are assumed to be time invariant, but norm-bounded. The purpose of the robust stabilization problem is to design state feedback controllers such that, for all admissible uncertainties, the closed-loop system is regular, causal and stable. In terms of strict LMIs, sufficient conditions for the solvability of the problem is presented, and the parameterization of desired state feedback controllers is also given. A numerical example is given to demonstrate the applicability of the proposed design approach.     

An overview of the applications and solutions of a fundamental matrix equation pair

Equation TA−FT=LC (F is stable) is necessary and sufficient for the output of a feedback compensator (F,L,K_Z,K_y) to converge to a state feedback (SF) signal for a constant K, where (A,B,C,0) is the open loop system and TB is the compensator gain to the open loop system input. Thus, equation TB=0 is (1) the defining condition for this feedback compensator to be an output feedback compensator. Equation TB=0 is also the necessary and sufficient condition to (2) fully realize the critical loop transfer function and robust properties of SF control if K is systematically designed. Furthermore, because B is compatible to the open loop system gain to its unknown inputs and its input failure signals, TB=0 is also necessary for (3) unknown input observers and (4) failure detection and isolation systems. Finally, this equation pair (TA−FT=LC, TB=0) is the key condition of a really systematic and explicit design algorithm for (5) eigenstructure assignment by static output feedback control. This paper reviews the existing solutions of this equation pair, and points out that a general and exact solution is uniquely direct, simple, and decoupled. This paper also points out that these unique features also enable two decisive advantages: (1) the systematic compensator order adjustment and (2) a simple and approximate solution which is general to all systems (A,B,C,0) and which can be simply added to the exact solution whether it exists or not.     

茄子皮天然红色素的提取及稳定性的研究

以茄子皮为原料,用酸性无水乙醇溶液浸泡提取天然红色素,并通过实验对色素溶液在不同pH值下在温度,光照,氧化还原剂,金属离子的稳定性进行了研究.实验证明:茄子皮天然红色素可以适用大多数食品,是一种值得开发的天然食用色素资源.     

花生牛奶饮料的稳定性工艺研究

通过对提高花生牛奶稳定性的主要影响因素的稳定剂配方、均质工艺、杀菌后的冷却方式进行试验研究。结果表明,单一的瓜尔豆胶、卡拉胶、黄原胶、CMC增稠稳定剂对花生牛奶饮料的稳定效果差;卡拉胶：瓜尔豆胶为50％：50％的复合增稠稳定剂对花生牛奶饮料有较好的稳定效果;卡拉胶、瓜尔豆胶、蔗糖脂肪酸酯用量分别为0．08％、0．08％、0．10％的增稠稳定剂与乳化剂复合的配方可大大提高花生牛奶饮料的整体稳定性;花生牛奶饮料的均质工艺以25Mpa压力采用两遍均质的方法效果较好;杀菌后以急速冷却方式可大大增加花生牛奶饮料的稳定性。     

一种基于PIFS的DWT水印算法

本文提出了一种基于分块迭代函数系(PIFS)的小波域水印算法。通过PIFS变换将水印图变换为自相似分形水印图,然后用小波变换进行水印的嵌入、提取。实验证明该算法有良好的鲁棒性,同时保证了水印的不可见性。     

复系数多项式凸组合的稳定性检验

两个给定的同次复系数多项式是Hurwitz稳定的,它们的凸组合是否也是Hurwitz稳定的?本文就此给出了一个检验方法.该方法以结式理论为依据,并应用了Sturm定理,不需求解多项式的根,仅经过有限步的运算就可完成对凸组合的稳定性判别,应用方便.     

基于SURF算法的视频贴片广告图标的检测方法

视频媒体中的广告元素随着商业化步伐日趋增多,媒体市场的监测部门常常需要检测视频中某个广告图标出现的时间位置和存在的时间长度。针对这一需求,一种基于SURF算法的视频贴片广告图标的检测方法被提出。首先详细介绍SURF算法,通过对匹配比的计算等改进,以定量表示图像间的匹配程度,并将改进后的方法引入视频贴片广告的检测工作中,提出了一种检测视频中出现的贴片广告图标的方法,最后使用实际视频作为用例对方法进行验证,效果良好,结果准确。     

反射布朗运动驱动的非线性系统的随机稳定化

研究了由随机噪声反射布朗运动干扰的非线性系统dx(t)=f(x)(t)dt的随机稳定化,建立了受干扰系统的几乎必然指数稳定性判定性定理并估计了相应的样本Lyapunov指数。     

Book Reviews

Abstract

The long-term stabilization of marine archaeological iron, whether cast or wrought, continues to challenge conservators responsible for treatment of this material. Results and observations obtained from past treatments highlight the daunting, prolonged, and laborious efforts required to desalinate large and complex ferrous artifacts recovered from the ocean. In general, the higher an artifact's chloride level, the less stable it is. Consequently, any stabilization treatment must involve the removal of as much Cl^?1 as possible without affecting the integrity of the corroded artifact. This problem is particularly acute with corroding cast iron objects that have formed thick, fragile, and highly unstable corrosion layers. Over the course of the twentieth century, conservators have used a variety of techniques in an attempt to mitigate the negative effects of chloride ions on iron artifacts and prevent disintegration. In spite of early promise, each of these stabilization techniques has significant disadvantages, particularly with regard to treatment efficiency, duration of treatment, and/or unacceptable risks to the artifact during treatment. For these reasons, conservators and conservation scientists at the Warren Lasch Conservation Center in Charleston, South Carolina, decided to look at the possibility of using subcritical fluids to stabilize archaeological iron. This paper compares the efficiency and effectiveness of traditional stabilization techniques (i.e. alkaline soaking and cathodic polarization) to subcritical fluids on wrought iron rivets and metal shavings from the H.L. Hunley submarine as well as Civil War era cast iron artillery shells recovered from a marine environment.