Topology optimization based on level set for a flexible multibody system modeled via ANCF

A topology optimization methodology is proposed for the flexible multibody system undergoing both large overall motion and large deformation. The system of concern is modeled via the absolute nodal coordinate formulation. The equivalent static load method is employed to transform the topology optimization of the nonlinear dynamic response of the system into a static one, and evaluated to adapt to the absolute nodal coordinate formulation by splitting the elastic deformations of the flexible components from the overall motions of those components. During the static topology optimization, the material interface is implicitly described as the zero level set of a higher-dimensional scalar function. Then, the semi-implicit level set method with the additive operator splitting algorithm is employed to solve the corresponding Hamilton-Jacobi partial differential equation. In addition, the expert evaluation method of weights based on the grey theory is utilized to define the objective function, and a modified augmented Lagrange multiplier method is proposed to treat the inequality volume constraint so as to avoid the oscillation and drift of the volume. Finally, two numerical examples are provided to validate the proposed methodology.     

New receipt-free voting scheme using double-trapdoor commitment

It is considered to be the most suitable solution for large scale elections to design an electronic voting scheme using blind signatures and anonymous channels. Based on this framework, Okamoto first proposed a receipt-free voting scheme [30] for large scale elections. However, in the following paper, Okamoto [31] proved that the scheme [30] was not receipt-free and presented two improved schemes. One scheme requires the help of the parameter registration committee and the other needs a stronger physical assumption of the voting booth. In this paper, we utilize the double-trapdoor commitment to propose a new receipt-free voting scheme based on blind signatures for large scale elections. Neither the parameter registration committee nor the voting booth is required in our scheme. We also present a more efficient zero-knowledge proof for secret permutation. Therefore, our scheme is much more efficient than Okamoto’s schemes [30] and [31] with the weaker physical assumptions. Moreover, we prove that our scheme can achieve the desired security properties.     

实现动态网页的一种新技术ColdFusion

介绍了ColdFusion技术的定义、工作原理、具体实例、应用前景。     

基于p范式模型的检索

随着电子文本的大量涌现,人们对信息检索工具提出了更高的要求。本文介绍一种扩展的布尔检索模型及其在中文信息检索系统中的应用,并利用相关反馈技术改善检索系统性能。     

基于进程管理的气象文件监控处理

文件实时监控处理过程在控制程序处理过程中被广泛运用。本文结合文件处理的实际工作,描述了文件处理程序的监控处理过程,实现了基于进程管理的文件监控处理与预处理过程的协同工作。     

曲线梁桥计算理论与设计实践问题探讨

曲线梁桥以其良好的适应性和动态美感在我国桥梁设计界出现频率逐年增高,然而其安全隐患和运营事故也随之出现.就此状况,从研究曲线梁桥的力学性能入手,结合工程实际对现有计算理论和设计方法进行归纳与分析,提出其中有待进一步研究解决的问题,以期为曲线梁桥的设计与实践提供参考建议.     

基于UC3637的永磁直线电机控制系统

由于旋转电机和直线电机的结构不同,其控制系统也有很大差异。该文介绍了1种将无刷直流旋转电机专用芯片UC3637在直线电机控制系统的应用实例,介绍了硬件和软件结构以及实验结果和应用。     

基于GSI的交互式网格安全认证研究

网格认证是网格安全的重要组成部分,是对网格实体身份有效性进行确定的过程。网格环境下虚拟组织为认证提出了新的要求。介绍了网格环境下虚拟组织的特点,阐述了网格认证的基本要求,分析了几项常用的认证技术不适合多结点网格认证的原因,在此基础上分析了Globus项目中基于GSI认证的相关技术及概念。网格技术是一项不断发展的技术,网格认证也处于不断完善之中。