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501.
减压环在被动柔性防护网中的耗能作用研究 总被引:1,自引:1,他引:0
《铁道标准设计通讯》2016,(9):36-41
基于落石防护措施受力系统的复杂性及不同系统参数研究的有效性角度考虑,数值方法正成为研究被动柔性防护网动态受力行为的重要手段。为研究被动柔性防护网中的减压环在落石冲击作用下的耗能及缓冲作用,以实际被动柔性防护网为原型,建立含减压环及不含减压环的两种被动柔性防护网有限元模型,基于ANSYS/LSDYNA分析两种防护网在不同冲击能量及冲击位置下的动力响应。研究结果表明:减压环可增强被动柔性防护网的柔性、改善作用部位的性能,同时能显著地提高被动柔性防护网的耗能能力。同时,数值结果的对比分析为下一步试验设计以校正有限元模型和研究实体构件受力特征提供了参考依据。 相似文献
502.
Outliers in traffic flow series represent uncommon events occurring in the roadway systems and outlier detection and investigation will help to unravel the mechanism of such events. However, studies on outlier detection and investigations are fairly limited in transportation field where a vast volume of traffic condition data has been collected from traffic monitoring devices installed in many roadway systems. Based on an online algorithm that has the ability of jointly predict the level and the conditional variance of the traffic flow series, a real time outlier detection method is proposed and implemented. Using real world data collected from four regions in both the United States and the United Kingdom, it was found that outliers can be detected using the proposed detection strategy. In addition, through a comparative experimental study, it was shown that the information contained in the outliers should be assimilated into the forecasting system to enhance its ability of adapting to the changing patterns of the traffic flow series. Moreover, the investigation into the effects of outliers on the forecasting system structure showed a significant connection between the outliers and the forecasting system parameters changes. General conclusions are provided concerning the analyses with future work recommended to investigate the underlying outlier generating mechanism and outlier treatment strategy in transportation applications. 相似文献
503.
504.
渡船安全一直是长江水上交通安全监管的重点和难点。文中总结提炼渡船安全管理的经验、措施和做法,运用模糊数学和层次分析法,探索建立渡船安全评价体系的新途径。 相似文献
505.
文章针对广西高速公路实行计重收费后交通量、通行费收入的变化情况,分析了高速公路通行费收入变化的特点与原因,提出了应对高速公路交通量流失的对策和方法。 相似文献
506.
The paper proposes a first-order macroscopic stochastic dynamic traffic model, namely the stochastic cell transmission model (SCTM), to model traffic flow density on freeway segments with stochastic demand and supply. The SCTM consists of five operational modes corresponding to different congestion levels of the freeway segment. Each mode is formulated as a discrete time bilinear stochastic system. A set of probabilistic conditions is proposed to characterize the probability of occurrence of each mode. The overall effect of the five modes is estimated by the joint traffic density which is derived from the theory of finite mixture distribution. The SCTM captures not only the mean and standard deviation (SD) of density of the traffic flow, but also the propagation of SD over time and space. The SCTM is tested with a hypothetical freeway corridor simulation and an empirical study. The simulation results are compared against the means and SDs of traffic densities obtained from the Monte Carlo Simulation (MCS) of the modified cell transmission model (MCTM). An approximately two-miles freeway segment of Interstate 210 West (I-210W) in Los Ageles, Southern California, is chosen for the empirical study. Traffic data is obtained from the Performance Measurement System (PeMS). The stochastic parameters of the SCTM are calibrated against the flow-density empirical data of I-210W. Both the SCTM and the MCS of the MCTM are tested. A discussion of the computational efficiency and the accuracy issues of the two methods is provided based on the empirical results. Both the numerical simulation results and the empirical results confirm that the SCTM is capable of accurately estimating the means and SDs of the freeway densities as compared to the MCS. 相似文献
507.
目前,我国各城市纷纷进行交通影响评价,在扬州市规划局和交警支队等相关部门的指导下,扬州市于2006年开始了交通影响评价工作。在阐述了扬州市交通影响评价的实践过程及基本要素的同时,给出了交通影响评价报告的编制内容。最后,总结了扬州市交通影响评价中存在的问题。 相似文献
508.
509.
多智能体技术在交通系统协调控制中的应用 总被引:6,自引:0,他引:6
多智能体在交通控制系统中的应用逐渐成为交通控制领域的一个研究热点.应用多智能体技术,建立交通系统控制模型逐步得到交通工程相关研究者的重视.在分析交通系统协调控制模型和多智能体技术在交通系统协调控制中的应用现状的基础上,提出了建立基于多智能体技术的交通系统协调控制模型应注意的问题和发展趋势,以期能为相关研究提供一种新的思路. 相似文献
510.
文章结合目前高速公路新建立交工程的实施情况,指出交叉工程进行交通管制的必要性和重要性,分析交叉工程交通管制的重点和难点,提出相应的交通管制措施和方法。 相似文献