基于改进遗传算法主动柔性结构压电元件位置优化

基于改进的遗传算法提出了一种解决多压电片布置在柔性结构上以实现振动主动控制的有效方法.本文采用D优化设计准则,即把Fisher信息矩阵行列式最大值作为目标函数的一种优化方法.通过对结构模态振型和动力特性的研究,使用一种简单的方法将所选择的低阶模态振型转化为归一化形式,最后通过结构模态振型可确定压电片最优位置.为了达到更好的振动控制效果,压电片布置在结构模态应变最大位置处.当在结构不同位置上布置压电片时,结构各阶模态振型也将随之发生不同程度的变化.本文建立了ANSYS软件和遗传算法的接口来实现对结构的模态重分析,从而提取各阶模态振型.     

TEACHING OF OPTIMAL CONTROL 1)

最优控制课程是控制科学与工程学科研究生学位必修课,同时也是力学(特别是动力学与控制方向)学位课,是一门具有理论深度和广泛工程应用的基础课。本文围绕如何提高课程教学质量、培养学生学习兴趣和创新能力的问题,对最优控制课程的教改核心、教学目标、教学内容、教学材料和教学方法等展开讨论。部分教改措施(如研讨式教学和BOPPPS教学结构)已应用于课程实践且取得良好效果。     

校园环境质量监测实践课程的实施与体会

校园环境质量监测实践课程是一门实践性很强的综合性实践课程。课程目标既有知识与技能目标,又有过程与方法目标,还有情感、态度和价值观目标。为了较好地达成课程目标,既要制定合理的实施方案,又要执行严格的实施过程。指导教师要做好集体备课、课前动员、分组指导、成绩评定和课后总结的每一个环节。     

Optimal decay rates and small global solutions to the dissipative Boussinesq equation

This work is devoted to the small amplitude solutions for the initial value problem of the multidimensional dissipative Boussinesq equation. We firstly derive the pointwise estimates of the fundamental solutions by the energy method in the Fourier space. We give the asymptotic profiles of solutions to the corresponding linear problem to get the optimal decay rate for the -norm of solutions in all space dimensions. Under smallness assumptions on the initial data, we study the global existence and uniqueness of solutions by the contractive mapping principle in the solution spaces with time weighted norm.     

Lie symmetries and travelling wave solutions of the nonlinear waves in the inhomogeneous Fisher-Kolmogorov equation

In this work, we consider a Fisher-Kolmogorov equation depending on two exponential functions of the spatial variables. We study this equation from the point of view of symmetry reductions in partial differential equations. Through two-dimensional abelian subalgebras, the equation is reduced to ordinary differential equations. New solutions have been derived and interpreted.     

关于具有Fuzzy约束的Fuzzy多目标规划非控解的存在性

本文对具有Fuzzy约束集的Fuzzy多目标规划引进Fuzzy非控点和Fuzzy非控解的概念,讨论了它们的一些基本性质和存在性。     

OPTIMAL QUADRATURE OF THE SOBOLEV CLASS W_1~r(R) DEFINED ON WHOLE REAL AXIS

ＯＰＴＩＭＡＬＱＵＡＤＲＡＴＵＲＥＯＦＴＨＥＳＯＢＯＬＥＶＣＬＡＳＳＷ_１~ｒ（Ｒ）ＤＥＦＩＮＥＤＯＮＷＨＯＬＥＲＥＡＬＡＸＩＳ（房艮孙，刘永平）￥ＦａｎｇＧｅｎｓｕｎ；ＬｉｕＹｏｎｇｐｉｎｇ（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＢｅｉｊｉｎｇＮｏｒｍａｌＵｎｉ...     

高级加密标准Mixcolumn变换设计分析

将最优线性映射的定义推广到一般域K上，由定义证明了域K上的方阵是最优的当且仅当它的所有子方阵可逆；发现了高级加密标准AES扩散层的一个新的性质：用同规模的任意循环最优线性映射取代AES的Mixcolumn变换，系统依然呈现出相同的抗差分攻击能力；因为AES的Mixcolumn变换是最优的线性映射，且其对应矩阵选取合理、便于软硬件的快速实现，所以其设计的确很好．     

用数字图像技术直接对双曝光散斑图像逐点分析

本文提出一种用数字图像技术直接处理双曝光散斑图,进行逐点分析而在视频监视器上产生杨氏条纹图,并由此测得位移大小与方向的新方法.     

Selecting tolerances in chance-constrained programming: A multiple objective linear programming approach

An importance issue concerning the practical application of chance-constrained programming is the lack of a rational method for choosing risk levels or tolerances on the chance constraints. While there has also been much recent debate on the relationship, equivalence, usefulness, and other characteristics of chance-constrained programming relative to stochastic programming with recourse, this paper focuses on the problem of improving the selection of tolerances within the chance-constrained framework. An approach is presented, based on multiple objective linear programming, which allows the decision maker to be more involved in the tolerance selection process, but does not demand a priori decisions on appropriate tolerances. An example is presented which illustrates the approach.