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671.
Hepatic computed tomography(CT) images with Gabor function were analyzed.Then a threshold-based classification scheme was proposed using Gabor features and proceeded with the retrieval of the hepatic CT images.In our experiments, a batch of hepatic CT images containing several types of CT findings was used and compared with the Zhao's image classification scheme, support vector machines(SVM) scheme and threshold-based scheme. 相似文献
672.
随着中国铁路"走出去"倡议的实施,中国标准体系下各设计阶段主要工作内容及方法在国外项目的应用差异性问题日益凸显。为提高中国企业参与国外铁路勘察设计进程,依据多个海外项目设计经验,通过对比分析国内外铁路设计过程的各阶段工作方法与特点,分别对国外项目前期研究、项目设计和工程实施3个阶段的主要工作内容及审批程序进行分析。研究认为,国外铁路项目设计各阶段工作内容与我国设计标准体系有一定差异,但存在对应关系;其中,可行性研究报告是前期研究阶段重要成果文件,编制深度可参考国内的预可行性研究;设计阶段一般细分初步设计和详细设计两阶段,文件编制深度由国内的可行性研究逐步过渡到初步设计;实施阶段重点落实施工图工作。 相似文献
673.
The interdependence and complexity of socio-technical systems and availability of a wide variety of policy measures to address policy problems make the process of policy formulation difficult. In order to formulate sustainable and efficient transport policies, development of new tools and techniques is necessary. One of the approaches gaining ground is policy packaging, which shifts focus from implementation of individual policy measures to implementation of combinations of measures with the aim of increasing efficiency and effectiveness of policy interventions by increasing synergies and reducing potential contradictions among policy measures. In this paper, we describe the development of a virtual environment for the exploration and analysis of different configurations of policy measures in order to build policy packages. By developing systematic approaches it is possible to examine more alternatives at a greater depth, decrease the time required for the overall analysis, provide real-time assessment and feedback on the effect of changes in the configurations, and ultimately form more effective policies. The results from this research demonstrate the usefulness of computational approaches in addressing the complexity inherent in the formulation of policy packages. This new approach has been applied to the formulation of policies to advance sustainable transportation. 相似文献
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675.
为了研究跨座式单轨固定铸钢支座铰轴与摆孔之间的接触应力,应用Hertz接触理论,分析影响铸钢支座接触应力的主要因素。采用有限元数值模拟的方法,借助ABAQUS有限元分析软件,建立固定支座的三维有限元模型,通过计算得到固定支座的接触应力。对支座进行静力荷载试验,对比试验结果与有限元计算结果,验证有限元分析结果的可靠性。最后借助有限元分析手段,计算铰轴直径变化对接触应力的影响。结果表明,固定支座在设计静力荷载作用下的接触应力满足要求,并且铰轴材料具有较大的强度富余;铰轴直径的尺寸会影响支座接触应力的大小,且存在最优铰轴直径使支座接触应力最小,可以为铸钢支座结构的设计与优化提供指导。 相似文献
676.
Z. L. Wang G. Q. Li Y. B. Yang S. W. Chen X. L. Zhang 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2019,57(2):161-191
This study presents a more realistic modelling of the maglev-based high-speed railway line in Shanghai, China. Focus is placed on an accurate simulation of the two subsystems: the train subsystem including the magnets and the viaduct subsystem including the modular function units of the rails. The electromagnet force–air gap model with a proportional-derivative (PD) controller is adopted to simulate the interaction between the maglev train via its electromagnets and the viaduct via its modular function units. The flexibilities of the rails, girders, piers and associated elastic bearings are all considered in the modelling of the viaduct subsystem to investigate their effects on an interaction between the two subsystems. By applying the proposed model to the Shanghai maglev line, the essential characteristics of the coupled system can be duly captured. The accuracy and effectiveness of the proposed approach are then validated by comparing the computed dynamic responses and frequencies with the measurement results. It is confirmed that the proposed modelling with a detailed simulation of the magnets and modular function units can duly account for the dynamic interaction between the train and viaduct systems. Moreover, the effects of the inclusion of the flexibilities of the rails, girders and elastic supports to the response of the coupled system are respectively investigated, the results of which prove that their involvements are essential to the accurate prediction of the response of the coupled maglev train–viaduct system. 相似文献
677.
介绍喷射混凝发展及其施工关键控制技术,应用XPM混凝土外加剂试验结果,解决了隧道施工过程中喷射混凝土回弹量、厚度、强度等问题,取得了较好效果。 相似文献
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680.
根据交通应急系统的特点,将评价原理和评价方法应用到交通应急系统项目的评价中。从复杂的指标体系中选出对评价影响最大的主成分,然后运用层次分析法对交通应急系统项目进行评价选优,从而为交通应急系统项目方案的评价和选择提供依据。 相似文献