遗传算法的收敛性分析

理论分析算法发生过早收敛的原因、收敛速度与各个控制参数以及适应度函数的关系,并提出与证明了判断遗传算法收敛性的统一判据。     

基于多元统计理论的干部评价模型与实证分析

以多元统计分析原理为依据，运用聚类分析、主成分分析、碎石检验准则对高校党政管理干部做出综合评价及实证分析，可以得出干部的分类和综合排序情况，为高校组织部门和人事部门考核、选拔、任用干部提供科学的测评依据。     

Design and testing of the Minotaur advanced grid-stiffened fairing

A composite grid-stiffened structure concept was selected for the payload fairing of the Minotaur launch vehicle. Compared to sandwich structures, this concept has an advantage of smaller manufacturing costs and lighter weight. To reduce weight the skin pockets are allowed to buckle visibly up to about 0.5 cm peak displacement.

Various failure modes were examined for the composite grid-stiffened structure. The controlling criterion for this design was a joint failure in tension between the ribs and skin of the structure. The identification of this failure mechanism and the assessment of bounding strains required to control it required extensive test and analysis effort. Increasing skin thickness to control skin buckling resulted in reduced strains between the skin and ribs.

Following the identification of the relevant failure criteria, a final design for the fairing was generated. The resulting 6 m tall fairing was constructed of a tow-placed carbon fiber composite grid structure that was over-wrapped to create a laminated skin. Upon completion of curing and machining, the fairing was cut in half to create the classic “clam-shell” fairing. Static qualification testing demonstrated the structural integrity of the fairing, thereby proving the design and manufacturing process. Loads were applied incrementally in a static loading scenario. The applied load envelope exceeded worst-case dynamic flight conditions with an added safety factor of 25%. At peak load the fairing maintained structural integrity while remaining within the required displacement envelope for payload safety.

Data were collected during the test from a variety of sensors including traditional displacement transducers and strain gages. In addition, full field displacement was monitored at critically loaded fairing sections by means of digital photogrammetry. This paper summarizes the test results, presents the overall performance of the fairing under the test loads, correlates test response and analysis, and identifies lessons learned.

Work continues at the Air Force Research Laboratory (AFRL) and Boeing to identify means of further controlling tensile failure of the un-reinforced polymer bonded joint between the ribs and skin. Stiffening of skin adjacent to the joints and introduction of lightweight foam jackets at the interior of the fairing both show promise of delaying joint failure to higher loads.     

Delay-dependent criteria for robust stability of time-varying delay systems

This paper deals with the problem of delay-dependent robust stability for systems with time-varying structured uncertainties and time-varying delays. Some new delay-dependent stability criteria are devised by taking the relationship between the terms in the Leibniz-Newton formula into account. Since free weighting matrices are used to express this relationship and since appropriate ones are selected by means of linear matrix inequalities, the new criteria are less conservative than existing ones. Numerical examples suggest that the proposed criteria are effective and are an improvement over previous ones.     

冗余自由度机器人性能指标的二次特性及其优化方法

指出了冗余自由度机器人优化的多种性能指标及其加权综合指标对单个关节的关节加速度具有二次抛物线关系。由此，提出一种通过对抛物线插值寻求综合性能最优解的方法。同时，本文还将冗余自由度机器人运动学和动力学求优化解的过程，转化为非冗余自由度机器人运动学和动力学求解，以便直接利用各种高效率的非冗余自由度机器人计算方法。     

广义Lienard方程周期振动同步的判据

基于线性时变系统的稳定性理论,李雅普诺夫直接法和Gerschgorin圆盘定理求得判定广义Lienard方程振动系统达到全局同步的几种不同的代数判据.理论上比较这些不同代数判据表明:根据李雅诺夫直接法得到的代数判据优于根据Gerschgorin圆盘定理得到的代数判据,而且通过适当选取李雅普诺夫函数可以得到更优化的代数判据.Rayleigh-Duffing方程作为数值算例进一步验证了理论结果.     

The development of human factors design guidelines

There is a growing information gap between the development of advanced human-machine systems, and the availability of human factors design criteria that can be applied during their design process. Despite increased interest in the development of human factors design guidelines, there also remains considerable uncertainty and concern regarding the actual utility of such information. Indeed, many existing human factors reference materials have been criticized by designers for being ‘too wordy’, ‘too general’, and ‘too hard to understand’. The development of clear, relevant, and useful human factors guidelines requires a judicious mix of science and art to overcome such criticisms. Specifically, while a number of empirical and systematic methods can be productively applied to their development, the final design guidelines will always represent a subjective integration of user requirements, design constraints, available information, and expert judgement. This paper summarizes procedures and heuristics associated with both the science and the art components of human factors design guideline development.     

路面施工质量控制指标体系及其模糊评价研究

针对路面施工过程中控制因素多和评价指标难以确定的特点,通过分析影响施工质量的因素,建立了全面定量化和定性化的施工控制指标体系模型.运用改进层次分析法计算指标权重,模糊综合评判分析施工控制情况.通过安徽某高速公路的施工质量控制进行实证分析,结果表明,该指标体系符合施工现状,可以多点控制路面施工质量;实现了施工的自主控制性和时效性,能有效达到实时监控施工过程的目的,为施工和管理提供决策支持.     

辽宁四道沟金矿找矿标志及地球化学找矿预测

通过四道沟金矿床找矿标志研究，及其对东西矿化带78，20号矿体地球化学探矿系统取样分析，分别确定了两矿体轴向分带序列．并经过对78，20号脉指示元素异常分析特点的综合统计分析，初步建立了金矿床的地球化学指示元素的轴向分带模式，从上、下是：Ti-CU-Sb-As-Bi-Ag-Au-Co-V-Pb，为确定预测盲矿体提供了较比可靠的地球化学勘查信息．并以此为依据，对20，78脉带深部找矿预测进行了较深入地讨论，结果表明，20号脉群深部找矿前景较大，78号脉群深部基于七中段显示出一定的有利成矿的地球化学找矿信息，同样存在盲矿体的可能性．     

对逻辑覆盖软件测试准则的公理化评估

由于形式规格说明采用一种精确、一致、容易被机器自动处理的符号系统来描述软件需求,因而形式规格说明为测试用例的自动生成和软件功能的验证提供了基础.在基于形式规格说明的测试过程中逻辑覆盖测试准则是一组常用的测试准则,如何选择和使用其中的每个测试准则是应用这组测试准则时面临的主要问题.因此分析和比较这组测试准则中每个测试准则的性质将为测试工程师选择测试准则提供指导和帮助.对测试充分性准则的公理化评估是一种比较测试准则的方式,这种方式将对理想的测试准则的直觉需求定义为一组公理,然后通过检查测试准则是否满足该组公理来分析和比较相应的测试准则.描述了一组理想的逻辑覆盖测试准则应该具有的性质和用来确定一个测试充分性准则是否完全的生成算法.这组性质被形式化地定义为一组公理.利用这种形式化的定义,用定理的形式精确地给出了这些性质之间的关系.最后通过这组公理系统来评估现有的逻辑覆盖测试准则.评估的结果为测试人员在实际过程中选择逻辑覆盖测试准则提供了指导.