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ABSTRACT Current cycle-network planning (CNP) at the local level tends to be dominated by a subjective-pragmatic approach in which it is only possible to consider a limited number of route alignment possibilities and development-sequencing scenarios. Although this method may produce acceptable results, it may also be true that the final design could be improved – and the construction efficiency could be enhanced – by a more comprehensive review of the available options in relation to the objectives of the intervention. Such objectives may include accident reduction, modal shift in favour of cycling, health benefits or strategic expansion of a network. This article presents work undertaken to demonstrate a holistic approach to CNP, based on a logically defined spatio-temporal model and allowing some semi-automated multiobjective optimization of network designs in a GIS-based decision-support system. The model is introduced briefly before a case study applying this model to development of a cycle network in a small town in northeast England is described. The results obtained from this case study and the implications of this research for cycle network planners are discussed. 相似文献
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It is an important subject to probe the structure in the medium by various kinds of detection methods in the geotechnical engineering. Based on the propagation theory of elastic wave in half-space layered medium, the propagation characteristics of elastic wave in layered medium with different elastic parameters are discussed using dynamic analysis of finite element method. It is known that the S-wave velocity, density and thickness of layer are related to the properties of the elastic wave including waveform characteristics, spectral characteristics and time-frequency characteristics. We pay special attention to the structure with low velocity interlayer. The impact imaging method is applied to the grouting construction of the immersed tube tunnel. Data acquisition and analytical method are introduced in detail. The grouting effects can be qualitatively evaluated by comparing the characteristics of elastic wave before grouting with those after grouting. Finally, a quantitative evaluation is obtained according to the relationship between energy response of elastic wave and impedance ratio. 相似文献
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滑动变压器在非接触电能传输系统中的研究 总被引:1,自引:0,他引:1
滑动变压器是自动化码头非接触感应电能传输系统的核心部件,可以实现高速货物运输小车的安全供电。根据滑动变压器气隙较长、漏磁较大的结构特点,建立滑动变压器基于耦合电感理论的状态空间数学模型,以及基于通用软件MATLAB/SIMULINK的仿真模型。该模型参数简明,使用方便。对各种补偿拓扑和谐振频率进行对比分析,验证了模型的有效性,同时为系统补偿方案和工作频率的选择了提供可靠依据。 相似文献
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无线网状网研究与发展 总被引:7,自引:0,他引:7
无线网状网WMN(wireless Mesh Network)是一种新兴的无线组网技术,支持节点多跳路由和转发功能,解决了有限发射功率条件下无线覆盖和数据吞吐率优化的两难问题。因其独特网状结构优势,无线网状网拥有比传统无线Ad hoc网络和无线局域网WLAN更高的可靠性、更高的数据吞吐率、更低的干扰以及更强的扩展性等特点,在军事通信网、公安移动数据网以及智能交通网络等领域对系统网络的设计具有重要价值。本文引入了WMN的概念及结构模型,详细介绍其特征及优势,并且分析其关键技术和热点问题,随后,提出一种轨道交通系统宽带无线覆盖应用模式,同时也介绍其他典型应用范例。最后,介绍了其标准化发展进程,并对其发展进行展望。 相似文献