交通运输系统复杂性刻画研究的现状及展望

综述了交通流混沌、交通运输系统的自组织和网络复杂性等三个领域的国内外研究现状,归纳出四方面难点:(1) 缺少系统的理论基础和完整的刻画程序;(2) 对象需要的数据量较大;(3) 刻画方法不能实现可比化度量;(4) 对交通运输系统的复杂性认识还停留在浅层次的阶段,如何针对系统的复杂特性进行管理和控制尚处空白.对研究方向进行了展望.     

水工大体积混凝土裂缝成因与防裂措施

大体积混凝土的施工质量的好坏直接影响项目功能的实现。分析了水工大体积混凝土裂缝的形成原因;提出了对大体积混凝土开裂的控制以预防为主,并从原材料、配合比以及施工控制三方面控制混凝土开裂的方法;最后对混凝土开裂后的处理方法进行了讨论。     

叠合式套拱加固带裂缝衬砌的变形规律试验研究

文章通过室内试验和理论分析等手段研究了套拱加固后结构的受力规律、破坏模式及承载力变化。利用石膏材料,按照1∶10(模型∶原型)的相似比,制作拱顶带纵向裂缝的素混凝土衬砌结构(裂缝深度为原衬砌厚度的1/3),并按叠合式套拱加固方案,进行钢筋混凝土套拱加固;养护后,通过室内全周径向加载装置,分级施加拱顶松散土压,并计入地层抗力的影响,研究带裂缝衬砌套拱加固后的承载能力及破坏规律。试验结果表明,叠合式套拱加固后,结构受力过程分三个阶段:"初期加载—套拱拱顶开裂、套拱拱顶开裂—拱顶叠合面裂缝出现、拱顶叠合面裂缝出现—试件破坏",关键部位破坏顺序为拱顶开裂—拱顶延性破坏—拱腰脆性断裂,整体破坏模式为延性破坏。     

A route guidance system considering travel time unreliability

Under a stochastic roadway, drivers need a route guidance system incorporating travel time variability. To recommend a customized path depending on the trip purpose and the driver’s risk-taking behavior, various path ranking methods have been developed. Unlike those methods, our proposed disutility method can easily incorporate a target arrival time in the ranking process by measuring how late the travel is and by penalizing it depending on the severity of lateness. In addition, the disutility-based route guidance system can properly address travel time unreliability that causes unacceptable disruptions to the driver’s schedule (i.e., unexpected long delay). We compare the disutility-based path ranking method with other ranking methods, the percentile travel time, the mean excess travel time, and the on-time arrival probability. We show that the disutility has stronger discriminating power and requires less solution space to find an optimal path. The most important advantage is that it can estimate a driver’s risk-taking behavior for each trip purpose by using the discrete choice analysis. We construct a simulation framework to acquire the travel time data on a hypothetical roadway. We analyze the data and show how various ranking methods recommend a customized path. Using the data, we show the advantage of the disutiltiy method over the other methods, which is generating a customized path with respect to the target arrival time by properly penalizing the travel time lateness.     

新能源汽车驱动电机阻力台架模拟的数据处理

利用Advisor建立新能源汽车电机仿真模型,对行驶工况进行仿真,利用交流测功机模拟汽车的行驶工况实现动力系统阻力模拟的台架试验,为电动汽车动力驱动系统电机选型、参数匹配提供试验参考。在台架模拟时为减小仿真误差,重点对仿真数据进行粗差处理,之后将该数据发往台架。实验证明:处理后的数据与实际行驶情况基本相符。     

现浇箱梁支架水箱预压施工工艺研究

结合实际工程从预压施工准备、施工工艺等方面对现浇箱梁的支架水箱预压过程进行了论述分析.结果表明,该法受力性合理,施工便捷.     

斗轮机悬臂皮带机驱动滚筒轴承运行故障及改进措施

外来磨料进入斗轮堆取料机的悬臂皮带机的驱动滚筒与减速箱低速轴连接端的轴承座内,导致多种事故的发生。通过诸如改变轴承座端盖密封结构,加装轴套和叶片,改用新润滑脂,基本解决了斗轮机悬臂皮带机驱动轴承由于外来磨料侵入导致事故的问题。     

Texture image classification using multi-fractal dimension

This paper presents a supervised classification method of sonar image, which takes advantages of both muhi-fractal theory and wavelet analysis. In the process of feature extraction, image transformation and wavelet decomposition are combined and a feature set based on multi-fractal dimension is obtained. In the part of classifier construction, the Learning Vector Quantization (LVQ) network is adopted as a classifier. Experiments of sonar image classification were carried out with satisfactory resuits, which verify the effectiveness of this method.     

如何检查网线性能

挑选网线时，若缺少测试环境，无法通过仪器对网线性能进行测试，不妨从检查网线外观来鉴别网线质量。     

Q900型二次补气阀试验台测试系统简介

采用工业控制计算机,在Windows软件环境下控制气流加载及测量部件,开发了摩托车二次补气阀测试系统,实现了二次补气阀流量特性和耐久性的自动检测。