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61.
Transportation system infrastructure often experiences severe flood-related disruptions such as overtopping, erosion, and scour. The ensuing damages can result in enormous direct and indirect economic losses to the traffic network and consequently the individuals through conditions like inaccessibility to commuters and reduction in traffic safety. Many studies have claimed that a robust transportation system could significantly prevent such consequences from natural hazards such as floods, highlighting the importance of robustness measures that could be used by decision-makers to properly manage flooded transportation system. Most available measures related to network robustness assessment are qualitative, and while some recent studies have focused on such evaluation using quantitative assessment approaches related to environmental or social-economic operations, they lack the holistic view towards robustness under flood events. This study develops a composite multi-scale transportation-system robustness model considering flood hazards by synthesizing geographical damage recognition, topological functionality analysis, network operation evaluation, and traffic-user loss estimation. This integrated model has been applied in a real-world highway network, mainly revealing that a given intensive flood occurrence at different locations may result in a variety of after-flood disruptions in the transportation network. To assist the asset owners with developing more reasonable prevention and recovery plans, the developed multi-scale robustness index presents both visible multi-denominational flood consequences and an overall post-event transportation-system robustness indicator. 相似文献
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针对现实中旅客需求的不确定性,将旅客需求划分为必须满足的确定性旅客需求和可适当满足的波动性旅客需求,以极小化铁路运营公司总运营成本为目标,利用轻鲁棒技术,构建不确定旅客需求下高速铁路鲁棒列车开行方案优化模型。本文所提出的优化模型无需事先给出线路备选集,只需提前输入铁路走廊相关参数和旅客需求分布,即可得到旅客需求驱动的列车开行方案,避免了备选集合设置不合理对列车开行方案质量的影响。另外,通过引入线性化技术将模
型转化为整数线性规划模型,利用MATLAB平台调用GUROBI进行求解。最后,将模型应用到武汉-广州高速铁路走廊上,验证了其有效性。结果表明,优化后的方案能更好地处理旅客出行需求的不确定性,为编制高速铁路鲁棒列车开行方案提供一定的理论依据。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(12):1853-1871
This article describes a method of vehicle dynamics estimation for impending rollover detection. This method is evaluated via a professional vehicle dynamics software and then through experimental results using a real test vehicle equipped with an inertial measurement unit. The vehicle dynamic states are estimated in the presence of the road bank angle (as a disturbance in the vehicle model) using a robust observer. The estimated roll angle and roll rate are used to compute the rollover index which is based on the prediction of the lateral load transfer. In order to anticipate the rollover detection, a new method is proposed in order to compute the time-to-rollover using the load transfer ratio. The used nonlinear model is deduced from the vehicle lateral dynamics and is represented by a Takagi–Sugeno (TS) fuzzy model. This representation is used in order to take into account the nonlinearities of lateral cornering forces. The proposed TS observer is designed with unmeasurable premise variables in order to consider the non-availability of the slip angles measurement. Simulation results show that the proposed observer and rollover detection method exhibit good efficiency. 相似文献
64.
对于支线型集装箱船来说,最终的装载能力往往取决于破损稳性,合理的分舱是提高分舱指数的有效手段。以某2500TEU集装箱船为例,首先对该船的原始模型进行简化并做鲁棒性分析,之后根据SOLAS 2009,借助国际通用软件工具生成大量分舱方案,通过对大量计算结果进行变量的敏感度分析,得出了水密横舱壁的数量及位置、边舱的宽度、二甲板及双层底的高度、压载舱的型式对分舱指数的影响。为设计者进行同类船的前期研发设计提供借鉴。 相似文献
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本文对电液伺服系统PDFSV控制的抗干扰问题进行了研究。通过理论分析和计算机仿真,证明电液伺服系统引进PDFSV控制能提高系统的抗干扰能力。 相似文献
67.
黄慧 《变流技术与电力牵引》2006,(1):23-29
具有薄n基区和低掺杂场截止层新结构的非穿通绝缘栅双极型晶体管NPT IGBT明显降低了总损耗.特别是场截止概念与挖槽晶体管单元的结合能产生通态电压最小、开关损耗最低、载流子浓度近乎理想的器件.这种概念在600V~6.5 kV以上的IGBT和二极管中得到了发展.当折衷性能和总耐量与电压和电流额定值无关时,低压器件的开关特性与高压晶体管(VBr>2 kV)的处理方法不同.采用HE-EMCON二极管和高达1 700 V的新型场截止NPT IGBT,几乎不受开关性能的限制,不过,需考虑的是外部栅极电阻必须取确定值.相比低压晶体管,高压器件的电流密度较低,因而高压二极管和IGBT中的"动态"电场强度更临界. 相似文献
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