Eight-node conforming straight-side quadrilateral element with high-order completeness (QH8-C1)

A new eight-node conforming quadrilateral element with high-order completeness, denoted as QH8-C1, is proposed in this article. First, expressions for the interpolation displacement function satisfying the requirements for high-order completeness in the global coordinate system are constructed. Second, the displacement function expression in global coordinates is transformed into isoparametric coordinates, and the relationships between the two series of coefficients for the two kinds of displacement function expressions are found. Third, the displacement function expression is modified to satisfy the requirements of nodal freedom and interelement boundary continuity. The key to the new element construction is the derivation of the linear relationship expressions among 12 coefficients of element displacement interpolation polynomials in the global and isoparametric coordinate systems. As a result, the relationship between quadratic completeness and interelement continuity is explicitly given, and a proof of the completeness and the continuity was conducted to theoretically guarantee the validity of the derivation results. Furthermore, in order to verify the correctness of the theoretical work, nine numerical examples were performed. The computation results from these examples demonstrate that QH8-C1 exhibited excellent performance, including high simulation accuracy, fast convergence, insensitivity to mesh distortion, and monotonic convergence.     

浅析建设工程施工合同中几个条款

对比FID IC施工合同条件,指出了我国建设工程施工合同示范文本中几个条款中的不足,并提出了改进的相应建议。改进后的合同更加完备,将有利于减少合同履行中纠纷的出现。     

瑞雷波检测在水泥土搅拌桩中的应用

本文详细介绍了瑞雷波检测水泥土搅拌桩的方法和步骤,对该方法加以详细设计,并结合自己做过的工程实例具体分析、总结。通过与其他常规方法的对比、分析总结出该方法的优点并对桩基无损检测给与了建议。     

基于属性的访问控制策略的正确性验证

基于属性的访问控制策略以更精确的粒度控制着用户或进程对系统资源的访问,因此获得了越来越广泛的应用。然而必须保证所制定策略的正确性,才能防止对系统资源的非法访问,因此必须研制出一种有效的方法来验证策略的正确性。基于模型检测技术提出了一种访问控制策略的覆盖性与完整性验证方法。主要思想是将覆盖性与完整性验证归约为模型检测问题。将规则集与其变异分别视为模型,以模态逻辑公式描述其性质。调用模型检测算法,分别在模型及其变异模型上检测性质,生成反例报告以确定模型故障点和模型规则缺失点,同时分析性质本身的完善性,最终以完善后的模型和性质再次调用模型检测算法来完成覆盖性与完整性验证。实例分析结果表明覆盖性验证能够有效发现错误的规则,完整性验证能够有效识别验证规则的完备性。方法依托于模型检测工具完成,具有自动化程度高、易操作、测试结果可靠的特点。     

基于扩展层次自动机的UML状态图完备性和一致性检验

UML状态图是UML中重要的建模元素之一,用以描述软件系统的离散行为。完备性和一致性是UML状态图模型最重要的性质之一,是进一步验证模型行为正确性的前提。给出了状态图模型完备性和一致性的定义,研究了对完备性和一致性进行检验的方法。该方法首先把状态图模型变换成扩展层次自动机(EHA),然后对EHA进行分析。EHA中间格式消除了状态图的复杂性,简化了冲突迁移的优先级判别,便于设计简捷有效的算法对完备性和一致性进行检验。该方法的主要优点是利用了EHA的特性,给出了组合状态上迁移的传播算法,解决了完备性和一致性分析的难点。     

梯形模糊数上的完备度量及其在多属性决策中的应用

为充分利用梯形模糊数的信息,本文定义了梯形模糊数上一种新的距离,证明了该距离具有完备性。利用这种距离,针对梯形模糊数上的多属性决策问题,给出了一种基于理想点的决策方法。对属性权重的"归一化"处理使得这种方法具有简单易行的优点,最后以实例说明了该方法的有效性。     

部分K值逻辑中最小覆盖之判定的一些结果

根据部分K值逻辑完备性理论,证明了当m=2,σ=e时,若正则可离关系G₂=G₂（{1,2}）∪G₂之关系图的基础图仅为N图,则T（G₂）不是P_K*的最小覆盖成员。     

On the degree of completeness of cryptographic functions

This paper discusses the degree of completeness of cryptographic functions, which is one of the cryptographic criteria should be considered in the design of stream ciphers. We establish the re- lationships between the degree of completeness and other cryptographic criteria. For resilient Boolean functions, a method to enhance the degree of completeness is proposed, while the nonlinearity and the algebraic degree do not decrease. Moreover, two constructions of resilient functions are provided, which have optimal degree of completeness, high nonlinearity, and high algebraic degree.     

全自主移动机器人在未知环境中的运动规划

针对机器人在未知环境中的运动规划,本文给出了一种基于激光传感器的完备路径规划算法,使机器人可以有效地扫描整个未知环境。使得机器人扫描整个未知环境的行走路径较短,所需的时间也较短。计算机仿真验证了算法的可行性,同时体现了算法的优越性。