On the elasticT-term of a main crack induced by near tip microcracks

In the expansion form of the stress field near a crack tip, the nonsingular and constant stress acting parallel to the crack plane is called the elasticT-term, which is very important in fracture analysis. The elasticT-term of a main crack induced by near tip microcracks is analyzed. The original problem considered consists of a main crack accompanied by near tip microcracks, which are loaded remotely by the first three terms of the crack tip stress field expansion parameterized by stress intensity factorsK _I ,K _II , and the nonsingular stress, i.e., theT-term,. With the principle of superposition, the problem can be reduced to a system of Fredholm integral equations which can be solved numerically. After obtaining the solution, the induced elasticT-term is evaluated. Several typical numerical examples are given and the results are shown in Figures, from which some useful discussion and conclusions are obtained.     

Macro-ergonomic risk assessment in nuclear remediation industry

In this study, a macro-ergonomic risk assessment tool was developed based on criteria of scope, simplicity, practicality, usefulness, reliability and job-specificity. A relative stress index 'RSI' was formulated to take into account multiple parameters, such as frequency, duration, repetition, weight, force, travel distance and horizontal distance. This tool was tested in nuclear remediation industry. The results are presented and discussed.     

Potentials of IR-UWB technology for ubiquitous computing

Connectivity is very important to enable ubiquitous computing. Wireless communication plays a continual key role in future ubiquitous network where all devices need to be connected freely. Ultra-wideband (UWB) radio is a new method of short-range wireless technology which is suit for ubiquitous computing. In this paper, we provided the potentials of impulse radio UWB (IR-UWB) technology in ubiquitous computing environments. Our study investigated possible communication methods which can be used in ubiquitous network. Comparisons between different communication technologies demonstrated that UWB-based solutions can support identification, location, sensing, and connectivity. In addition, we proposed two typical schemes which show how IR-UWB is used in ubiquitous computing.     

高精度定时方法在舵系统测控中的应用

首先阐述了舵系统的工作特点和测控原理,针对其仿真测控过程中的精确定时需求,研究了Windows 2000系统下几种定时器的性能和用法,然后提出一种Windows高精度性能定时方法,在Visual C++6.0编程环境下,开发出一种高精度定时模块,该模块具备计时、三种延时等待功能接口;经试验测试,该模块定时精度可达μs级;最后将该定时模块应用于某舵系统的测试控制中,结果表明能较好地满足舵系统的测控应用的定时精度要求。     

基于ZigBee技术的建筑能耗监测系统设计

随着我国建筑总量不断攀升,建筑能耗也逐年增加,更加有效地实施建筑能耗统计及建筑节能管理具有重要的意义;通过对建筑能耗监测系统的分析,在研究ZigBee技术的基础上,提出了基于ZigBee无线传感器网络的建筑能耗监测系统总体结构,对其网络拓扑控制和路由协议进行了研究,并介绍了系统周期性工作过程;网络测试表明,该系统可靠性好,能够实现建筑能耗数据的采集和无线传输;通过对能耗数据的统计分析,为降低建筑能耗和提高建筑能效,提供了决策依据和参考.     

伪码调相雷达高度表中多径信号抑制算法研究

多径误差是伪码调相雷达高度表中重要的误差源之一,为了提高系统的测距精度,建立了采用strobe相关器的伪码跟踪环数学模型,给出了其实现的结构框图;在考虑单路多径信号的基础上分析了多径信号的参数对伪码跟踪环的跟踪误差的影响,并在Matlab环境下对伪码跟踪环的跟踪性能进行了仿真;仿真结果表明在相同的多径参数条件下,strobe相关器可以有效地减小多径引起的跟踪误差,性能优于窄相关器,运算量较多径估计延迟锁定环要小,易于在硬件上实时实现,具有实际应用价值。     

无线传感器网络簇级拓扑演化模型研究

复杂网络理论研究表明,复杂系统的容错能力不仅仅存在于具有冗余组件的系统之中;而且也同样存在于具有无标度(scale-free)特征的网络之中;文章借助于复杂网络理论和偏好依附机制提出一种无线传感器网络簇级拓扑演化模型;拓扑动态分析表明,该模型能够很好地体现无线传感器簇间的拓扑生长过程,由该模型演化成的无线网络拓扑具有无标度网络的性质,所以该拓扑模型具有很强的容错性。     

基于视频图像的车牌定位预处理算法

车辆图像的预处理效果的好坏直接影响着车牌定位的准确率和运算速度;为了去除复杂背景区域的影响,消除图像的噪声,提出了一种针对视频序列改进的预处理流程;基于混合高斯背景建模结合小波包多尺度去噪的思想,去除大量的背景信息,缩小了车牌定位的范围再继续后面的预处理工作;上述方法得到的图片,噪声干扰降低且含有较少的不规则连通区域,分别以文献[6]和文献[7]提供的车牌定位方法为例进行测试,效果良好。     

多源信息融合在故障诊断技术中的应用研究

从数据源的空间表示和信息源的可计算性两个方面阐述了信息融合应用于故障诊断的数学基础,然后引入信息论中有关“熵”、“条件熵”、“平均条件熵”和“互信息”等概念,从信息论的角度证明了信息融合在故障诊断中的有效性和实用性。最后结合信息融合技术与装备故障诊断实践,给出了具有通用性的信息融合故障诊断的模型框架。     

基于Qt的井间地震运动学正演软件编制

Qt是跨平台的应用程序和UI框架,将Qt应用与石油地球物理软件的开发能达到事半功倍的效果.文章介绍了井间地震运动学正演软件的交互建模模块、正演结果显示模块等各个模块的功能.并用Qt实现各个模块的功能,完成了软件的编制.最后用一实例验证了软件的功能和正演结果的正确性.