基于遗传算法和参数化建模的非线性结构优化

提出了一种对存在接触关系的非线性结构(装配体)进行优化设计的新方法。该方法将遗传算法与结构几何及有限元参数化建模方法相结合，在通用CAE软件的二次开发编程环境中实现对带接触的结构装配体进行结构尺寸和形状优化设计。文中利用该方法对某浮动式闭气结构的重要结构参数和关键构件形状实施了优化设计，使其闭气性能得到大幅度提高，体现了本文方法在解决这类优化问题中的优势。本文的方法有利于拓宽结构优化技术在机械设计领域的应用范围。     

平台框架设计中刚度的软件计算

以卡氏定理为理论基础,对平台框架类型及其截面形状用matlab进行了软件编写工作.通过平台框架设计的参数化、模块化,实现了框架刚度的最优化设计.应用该软件对某型号产品的平台框架类型和截面形状进行了优选搭配,找出了符合整体设计要求的最优化的搭配组合;另外,该软件还可以给出不同参数对刚度和自振频率的影响结果,实现了设计中的特征尺寸、关键尺寸的优化设计.该软件的应用及其结果表明:该软件实现了平台框架设计的参数化、模块化;能够对设计起到优化的作用;并可以一定程度上缩短设计周期.     

Energy–time uncertainty relations and time operators

It is proved that for any Hamiltonian in a separable Hilbert space, having a non-empty absolutely continuous spectrum, there exists a time operator densely defined in the subspace of absolutely continuous vectors. This result is obtained by using the Carbó-Dorca parameterized vector spaces and the spectral representation theorem for self-adjoint operators in Hilbert spaces. The restriction of the Hamiltonian to the absolutely continuous subspace and its time operator are incompatible. These results bring a completely new light on the energy–time uncertainty relations. The possible physical interpretations and related facts are also examined.     

随机优化磨光算法对卫生陶瓷进出口的分析模型

结合磨光法和最优化理论提出一种随机优化磨光算法(SOS算法),算法通过原始值的参数化和调整幅度的修改,利用优化理论优化控制点.实例表明,随机优化磨光算法比样条修正磨光法和灰色马尔可夫链预测模型精度要高得多;而且所得到的误差变化更稳定.     

Robust H{infty} dynamic output feedback control for 2D linear parameter-varying systems

James Lam Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Changhong Wang Space Control and Inertial Technology Research Center, Harbin Institute of Technology, Harbin 150001, People's Republic of China Corresponding author. Email: ligangwu{at}hit.edu.cn Email: james.lam{at}hku.hk Email: cwang{at}hit.edu.cn Received on June 28, 2006; Accepted on October 1, 2007 This paper is concerned with the problem of robust dynamicoutput feedback control for 2D discrete-time linear parameter-varyingsystems. Given a Fornasini–Marchesini local state-spacesystem with linear varying parameters, our attention is focussedon the design of full-order dynamic output feedback controller,which guarantees the closed-loop system to be asymptoticallystable and has a prescribed disturbance attenuation performance.A sufficient condition for the existence of a desired robustoutput feedback controller is established in terms of parameterizedlinear matrix inequalities, and the corresponding controllersynthesis is cast into a convex optimization problem which canbe efficiently handled by using standard numerical software.A numerical example is provided to illustrate the effectivenessof the proposed design method.     

Software Engineering and complexity in effective Algebraic Geometry

One may represent polynomials not only by their coefficients but also by arithmetic circuits which evaluate them. This idea allowed in the past fifteen years considerable complexity progress in effective polynomial equation solving. We present a circuit based computation model which captures all known symbolic elimination algorithms in effective Algebraic Geometry and exhibit a class of simple elimination problems which require exponential size circuits to be solved in this model. This implies that the known, circuit based elimination algorithms are already optimal.     

Post-post-Newtonian deflection of light ray in multiple systems with PPN parameters

The post-Newtonian scheme in multiple systems with post-Newtonian parameters presented by Klioner and Soffel is extended to the post-post-Newtonian (PPN) order for light propagation problem in the solar system.Under considering the solar system experiment requirement,a new parameter ε is introduced.This extension does not change the virtue of the scheme on the linear partial differential equations of the potential and vector potential mentioned in previous work.Furthermore,this extension is based on the former work done by Richter and Matzner in one global system theory.As an application,we also consider the deflection of light ray in the global coordinates.And the deflection angle of light ray is obtained with post-Newtonian parameters.