Ground truthing sediment profile imagery with traditional benthic survey data along an established disturbance gradient

Macrobenthic surveys are an expensive, slow and labour intensive means to establish the health of benthic communities. Sediment profile imagery (SPI) is a means of rapid reconnaissance for monitoring large areas of the benthos. SPI has often been used to monitor gross anthropogenic disturbance. The aim of this study is to determine if SPI can be used as a tool to reliably map change in communities along natural estuarine gradients. Macrobenthic sampling was carried out at five stations along an established estuarine gradient. This faunal data was analysed using standard multivariate techniques and to ground truth a concurrent SPI survey. Faunal analysis showed that habitat quality in Inner Galway Bay was generally good, with some localised disturbance from the River Corrib and the sewage out flow exterior to the city dock. Four distinct groups were identified with a degree of overlap occurring between stations 3 and 4. While existing SPI indices mapped habitat quality in the same manner as the faunal data for end member stations, the level of distinction between the habitats of an intermediate staging was found to be poor. This lack of distinction amongst the stage 2 and 3 stations was overcome by developing a tailored index, the Galway Bay index of habitat quality (GBHQ). This index was derived from the 5 observed variables in the SPI data that were determined to best match the faunal distribution by permutative mantel testing. The 5 observed variables from the SPI data were the depth of the apparent redox potential discontinuity (aRPD), the depth of penetration by the prism, and the presence/absence of infauna, surface faecal pellet layer and biogenic mounding. The GBHQ was able to distinguish between the 5 stations to a greater extent than previously described indices, showing clearly the separate groupings defined by the faunal data. The index was tested on a follow up SPI survey and shown to be applicable in mapping a broader range of habitats in Galway Bay. Indices generated for localised mapping of estuarine gradients should be derived from observed features and be ground truthed using faunal data. Some aspects of the GBHQ should be generally applicable to fine grained boreal estuarine sediments (aRPD/penetration), while others may be of limited utility in other locations depending on the digging characteristics of the particular SPI camera, and local factors influencing the persistence of biogenic features in the profile. This derivation technique provides a simple way to optimise SPI to particular studies and localities.     

Managing transportation during highway reconstruction: A recommended process

Major highway reconstruction can cause significant disruptions to existing travel patterns and economic activity. Reducing these impacts on travelers, shippers, businesses and residents requires that innovative and effective transportation management actions be developed and implemented. This paper reports the major findings and recommendations of a research study on managing transportation during highway, reconstruction. The primary objectives of the study were

Regional impacts of new transport infrastructure: a multisectoral potentials approach

This is the second of two background papers sponsored for the Symposium by the Administrative Commission for the north of the Netherlands. Its purpose is to provide an indication of the effects of the proposed high speed rail line between Amsterdam, Groningen and Hamburg on employment in the corridor. The authors first review the techniques of forecasting these effects discussed in the literature. The potentials approach is adopted for their analysis, the mathematics and underlying assumptions of which are presented. Finally, this model is run to provide an estimate of the impact on regional employment of three variants of the proposed rail line.     

地铁屏蔽门的常见故障

北京地铁5号线地下车站屏蔽门系统采用西屋公司的全高安全门,具有安全、节能、减噪等优点。但当屏蔽门发生故障时,会对乘客及车辆造成影响。在诸多故障中,常见故障包括：站台单元控制器故障、安全回路故障、驱动电源故障、绝缘故障。针对这4种常见故障进行分析,阐述其发生原因及处理办法。     

客运专线ZPW-2000A轨道电路应用分析

介绍客运专线ZPW-2000A轨道电路的结构组成,分析应用特点,阐明其与既有ZPW-2000A设备相比所具备的先进性及高可靠度,提出日常维护和故障处理的建议。     

驾驶员稳态预瞄动态校正假说

针对汽车运动学和动力学自身的特点及驾驶员对其的理解和认识，基于预瞄跟随理论和预测控制理论，在驾驶员行为建模中作出了汽车运动学和动力学特性的分隔处理，提出了驾驶员稳态预瞄动态校正假说，并结合仿真计算和驾驶模拟器实验论证了假说的合理性和有效性。     

抑制制动器振动噪声的阻尼方法的探讨

针对在盘式制动器制动块底板上粘贴一层阻尼层(Insulating Shim)的阻尼处理方法，首先指出制动块底板上阻尼层的减振机制在于粘弹性材料在接触面间表现出的摩擦作用，尤其取决于材料本身的迟滞效应。然后．定量分析了阻尼层对制动器噪声的抑制效果；利用能量等效原理将接触摩擦转换成系统中粘性阻尼后进行特征分析．考察系统稳定性。     

具有模块化结构的汽车动力学仿真模型的初步研究

初步探讨了面向开发型驾驶模拟器的具有模块化结构的汽车动力学仿真模型建立方法，从而可以在此基础上进一步建立一套通用的面向结构的汽车动力学仿真程序，便捷地在开发型驾驶模拟器上实现对不同类型或同类型不同结构车辆性能的仿真。     

轿车前梁有限元分析

利用轿车前梁的CATIA模型建立其有限元模型。通过前悬架的ADAMS模型确定前梁的受力。应用这些方法将CAD、CAE有机的结合在一起，提高了有限元分析的效率和准确性。为了检验模型的精确程度，对前梁进行了静态加载试验。结果表明计算和试验结果有很好的一致性。     

基于神经网络的半主动悬架自适应模糊控制

提出了基于神经网络的自适应模糊控制策略。模糊控制主要用来对付系统的非线性；神经网络根据振动响应的方差递推结果来辨识车体的振动情况实时调节模糊控制器的量化因子，使模糊控制器对路面的变化具有自适应的能力。在半主动悬挂1／4车非线性模型的基础上进行了仿真研究。