Dynamic analysis of arrest of buckle propagation on a beam on a nonlinear elastic foundation by FEM

Based on the dynamic governing equation of propagating buckle on a beam on a nonlinear elastic foundation, this paper deals with an important problem of buckle arrest by combining the FEM with a time integration technique. A new conclusion completely different from that by the quasi-static analysis about the buckle arrestor design is drawn. This shows that the inertia of the beam cannot be ignored in the analysis under consideration, especially when the buckle propagation is suddenly stopped by the arrestors.

考虑海床变形的裸露悬跨海底管道静力分析

针对裸露悬跨海底管道,考虑线弹性海床刚度,利用梁的小挠度理论,研究管道在自重作用下的变形和内力,推导给出了未脱离海床的管道段和悬跨管道段的变形和内力公式。在跨度较大的悬跨情况下,悬跨管道段较大的向下弯曲变形可能引起海床上管道脱离海床而翘起。建立管道翘起的判定准则,对于翘起情况推导相应的计算公式,通过算例给出翘起情况下管道的变形和内力。通过计算分析发现：工程上多数悬跨是翘起情况,没有翘起的计算公式只适应于跨度较小的悬跨管道。同时翘起情况下不同海床刚度对悬跨管道无量纲内力影响不大。

精确的程序静态分析

程序的静态分析是程序语言和编译领域的一个重要研究方向，已经被研究了很多年。近年来，它也引起形式方法和软件工程领域的重视，被用于程序测试和正确性验证。文中从程序的语法特征、所关心的数据类型和程序性质等方面比较了一些静态分析技术。着重描述基于路径的分析方法，特别是符号执行技术，讨论了程序路径可行性分析问题及其分类、复杂度。针对程序分析精度的一种量化指标，说明了其计算方法。

程序静态分析技术与工具

静态分析对于保证程序质量,提高软件生产率有重要的意义.本文综述了静态分析常用的策略,介绍了当前静态分析的研究现状,比较了目前已有的静态程序分析工具.

automated test case generation for the stress testing of multimedia systems

With the advancement in network bandwidth and computing power, multimedia systems have become a popular means for information delivery. However, general principles of system testing cannot be directly applied to testing of multimedia systems on account of their stringent temporal and synchronization requirements. In particular, few studies have been made on the stress testing of multimedia systems with respect to their temporal requirements under resource saturation. Stress testing is important because erroneous behavior is most likely to occur under resource saturation. This paper presents an automatable method of test case generation for the stress testing of multimedia systems. It adapts constraint solving techniques to generate test cases that lead to potential resource saturation in a multimedia system. Coverage of the test cases is defined upon the reachability graph of a multimedia system. The proposed stress testing technique is supported by tools and has been successfully applied to a real-life commercial multimedia system. Although our technique focuses on the stress testing of multimedia systems, the underlying issues and concepts are applicable to other types of real-time systems.

基于静态分析的强制访问控制框架的正确性验证

现阶段对操作系统的强制访问控制框架的正确性验证的研究主要集中于对授权钩子放置的验证.文中基于TrustedBSD MAC框架对强制访问控制框架的正确性验证问题进行了研究,在授权钩子放置验证的基础上,提出了安全标记的完全初始化验证和完全销毁验证.为了实现上述验证,文中提出了一个路径敏感的、基于用户自定义检查规则的静态分析方法.该方法通过对集成于编译器的静态分析工具mygcc进行扩展来验证强制访问控制框架的钩子放置的准确性和完备性.该方法具有完全的路径覆盖性,且具有低的误报率和时间开销.

二进制程序安全缺陷静态分析方法的研究综述

对现有二进制程序安全缺陷静态分析方法进行了综述和分析,提出了整个程序分析过程中的关键问题以及二进制程序安全分析的主要研究方向.通过对二进制程序缺陷静态分析流程的总结,发现二进制程序信息恢复是整个分析过程的关键,构造内容丰富的、通用的中间表示是二进制程序缺陷分析的重要研究方向.

Vacuum window of intermediate energy heavy-ion microbeam irradiation facility

The beam must be extracted into the air through the vacuum window to irradiate the living cell. In the window design, the material and thickness must be chosen to compromise the beam spot size broadening and the window safety. The structure-static analysis on the window of different structures and materials is done with the finite element analysis method, and the deformation and the equivalent stress axe simulated. The safety of these candidates is investigated using the intensity theory. In addition, the small angle scattering and the transverse range of ions are simulated using SRIM code, including all the effects on the beam spot size broadening, such as the incident ion energy, the material and the thickness of the window and the air composing. At last, the appropriate vacuum windows are presented, including the structure, material and thickness.

remote attestation for custom-built software

Huazhong Univ Sci & Technol, Natl Tech Univ Ukraine, Huazhong Normal Univ, Harbin Inst Technol, IEEE Ukraine Sect, I& M/CI Joint Chapter

节能型自治式多功能海洋环境监测系统的静力分析和姿态计算

海洋监测是人类认识海洋、研究海洋的有利工具，海洋自动观测仪器又是海洋监测技术最基本的硬件单元。文章介绍了一种具有自主知识产权的海洋仪器产品——节能型自治式多功能海洋环境监测系统，并对其做了静力分析和姿态计算。 该测量系统将定点锚泊潜标和浮标技术相结合，并创新性的融进了节能技术，使其具有长期、安全和多参数测量的工作特点。 为确保系统能在水下长期可靠地工作，文章对系统在水下的受力状况和姿态进行了计算。由于系统潜标式主浮体在水下几十米，海面波浪对其影响较小，仅对系统在海流的作用下进行水下静力分析。计算中首先根据总体技术要求进行合理的简化和假设，建立水下系统的数学模型，编制系统在水下的受力和姿态计算软件，完成系统的结构配置、受力分析和水下姿态的计算。 值得注意的是，该系统的潜标式主浮体受力分析方法与传统简单构形（一个浮体，一根索和一个锚）的分析方法不同，因为该潜标式主浮体不但受到下端缆绳的拉力，而且还受到连结上端搭载平台缆绳的拉力，同时还要考虑进变化海流对缆绳的作用。 最后，用MATLAB编制了相应程序。该程序操作方便，每次任务确定之后，只需向计算机输入阻尼系数、浮力重力值、浮球直径及潜标长度等参数，程序将自动计算出水下系统在 流速范围内各部件的横倾角、缆绳拉力及拉力与水平线（垂直线）夹角等有关参数，供系统配置做参考。

《机器人》杂志论文及作者的统计分析研究

本文通过对我国核心科技期刊《机器人》杂志 1990～ 1999年 10年间发表的论文及作者的统计分析 ,展示了我国在机器人学方面理论和应用研究的发展水平 ,揭示了从事机器人及相关技术理论与应用研究人员的现状和地区 ,系统分布的特点与规律 ,并以文献计量学的方法确定本刊的核心作者 ,活跃作者群的数量及比例 .对作者的年龄和性别结构、篇均作者数、作者增变量、滞稿期和论文基金项目等的统计结果进行综合分析 ,并提出几点看法 .

Static Shape Control Employing Displacement-Stress Dual Criteria

An approach employing displacement-stress dual criteria for static shape control is presented. This approach is based on normal displacement control, and stress modification is considered in the whole optimization process to control high stress in the local domain. Analysis results show that not only is the stress reduced but al so that the controlled surface becomes smoother than before.

Static Study of Cantilever Beam stiction under Electrostatic Force Influence

The model and analysis of the cantilever beam adhesion problem under the action of electrostatic force are given. Owing to the nonlinearity of electrostatic force, the analytical solution for this kind of problem is not available. In this paper, a systematic method of generating polynomials which are the exact beamsolutions of the loads with different distributions is provided. The polynomials are used to approximate the beam displacement due to electrostatic force. The equilibrium equation offers an answer to how the beam deforms but no information about the unstuck length. The derivative of the functional with respect to the unstuck length offers such information. But to compute the functional it is necessary to know the beam deformation. So the problem is iteratively solved until the results are converged. Galerkin and Newton-Raphson methods are used to solve this nonlinear problem. The effects of dielectric layer thickness and electrostatic voltage on the cantilever beamstiction are studied.The method provided in this paper exhibits good convergence. For the adhesion problem of cantilever beam without electrostatic voltage, the analytical solution is available and is also exactly matched by the computational results given by the method presented in this paper.

Instability Analysis Of Torsional Mems/Nems Actuators Under Capillary Force

The static and dynamic instabilities of a torsional MEMS/NEMS actuator caused by capillary effects are studied, respectively. An instability number, eta, is defined, and the critical gap distance, g(cr), between the mainplate and the substrate is derived. According to the values of eta and g, the instability criteria of the actuator are presented. The dimensionless motion equation of the MEMS/NEMS torsional actuator is derived when it makes nonlinear oscillation under capillary force. The qualitative analysis of the nonlinear equation is made, and the phase portraits are presented on the phase plane. In addition, the bifurcation phenomena in the system are also analyzed. (C) 2008 Elsevier Inc. All rights reserved.