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501.
License plate recognition (LPR) data are emerging data sources that provide rich information in estimating the traffic conditions of urban arterials. While large-scale LPR system is not common in US, last few years have seen rapid developments and implementations in many other parts of world (e.g. China, Thailand and Middle East). Due to privacy issues, LPR data are seldom available to research communities. However, when available, this data source can be valuable in estimating real-time operational metrics in transportation systems. This paper proposes a lane-based real-time queue length estimation model using the license plate recognition (LPR) data. In the model, an interpolation method based on Gaussian process is developed to reconstruct the equivalent cumulative arrival–departure curve for each lane. The missing information for unrecognized or unmatched vehicles is obtained from the reconstructed arrival curve. With the complete arrival and departure information, a car-following based simulation scheme is applied to estimate the real-time queue length for each lane. The proposed model is validated using ground truth information of the maximum queue lengths from the city of Langfang in China. The results show that the model can capture the variations in queue lengths in the ground truth data, and the maximum queue length for each signal cycle can be estimated with a reasonable accuracy. The estimated queue length information using the proposed model can serve as a useful performance metric for various real-time traffic control applications. 相似文献
502.
Few experimental data sets exist in the literature to support the development and evaluation of digital twins predicting structural degradation. The literature is especially sparse for system tests where multiple failures occur and interact. In this work, a laboratory-level experiment is conducted to mimic many of the properties of larger and more complex marine structures with redundant load paths, failure interaction, and component-to-system level integration. In the experiment, such properties are reflected by a hexagon tension specimen with four propagating fatigue cracks tested under displacement-controlled loading. The applied loading cycles and corresponding crack lengths are recorded as the major time-varying data of degradation, with the resisting force at maximum extension used as the system capacity. A novel computer vision method is used to measure the crack length. Strain gauges are also used to monitor the structure’s status. The experimental data is presented and analyzed in this paper. The resulting data sets can be used to evaluate the performance of different digital twin updating approaches. 相似文献
503.
504.
刘洋 《城市轨道交通研究》2021,24(4):58-61
通过对市域铁路车站到发线有效长度组成分析,从安全防护距离设置的原理着手,提出了两套能够缩短或转移安全防护距离的方案,进而缩短车站到发线的有效长度。对降低市域铁路地下车站的工程投资,减少市区内拆迁工程量,缩短施工工期等方面具有较强的实用价值。 相似文献
505.
Length-based vehicle classification is an important topic in traffic engineering, because estimation of traffic speed from single loop detectors usually requires the knowledge of vehicle length. In this paper, we present an algorithm that can classify vehicles passing by a loop detector into two categories: long vehicles and regular cars. The proposed algorithm takes advantage of event-based loop detector data that contains every vehicle detector actuation and de-actuation “event”, therefore time gaps between consecutive vehicles and detector occupation time for each vehicle can be easily derived. The proposed algorithm is based on an intuitive observation that, for a vehicle platoon, longer vehicles in the platoon will have relatively longer detector occupation time. Therefore, we can identify longer vehicles by examining the changes of occupation time in a vehicle platoon. The method was tested using the event-based data collected from Trunk Highway 55 in Minnesota, which is a high speed arterial corridor controlled by semi-actuated coordinated traffic signals. The result shows that the proposed method can correctly classify most of the vehicles passing by a single loop detector. 相似文献
506.
以千枚岩地质条件下的新两河关隧道为工程背景,基于上下台阶法和上半断面预留核心土法两种模型,利用FLAC-3D有限差分软件对不同台阶长度和核心土长度进行分析,获得了施工过程中合理的台阶长度和核心土长度. 相似文献
507.
体外预应力加固结构的钢索振动是其疲劳破坏和脱锚的诱因之一,基于拉索振动理论,对体外索的固有振动进行分析,研究和验证体外索的自由长度,研究成果可有效指导体外预应力加固工程实践。 相似文献
508.
为准确研究连续梁桥桥墩的屈曲失稳问题,本文取三联连续梁桥中的l联,用位移法建立了连续梁桥桥墩失稳通用平衡方程组以求得计算长度系数.该平衡方程组中,不仅考虑了线位移刚度和转角刚度的耦合影响,而且考虑了支座刚度、邻联抗推刚度和全桥地基刚度对计算长度系数的影响;不仅考虑了单墩在轴向力作用下刚度的影响,而且考虑了其余墩在轴向力作用下的整体屈曲反应.同时推导了邻联对桥墩的抗推刚度,给出了地基刚度的计算方法.并通过与有限元分析对比,验证了理论推导解析解的正确性.最后,给出了各因素作用下计算长度系数的对比结果. 相似文献
509.
510.