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101.
Traffic congestion has been a growing issue in many metropolitan areas during recent years, which necessitates the identification of its key contributors and development of sustainable strategies to help decrease its adverse impacts on traffic networks. Road incidents generally and crashes specifically have been acknowledged as the cause of a large proportion of travel delays in urban areas and account for 25% to 60% of traffic congestion on motorways. Identifying the critical determinants of travel delays has been of significant importance to the incident management systems, which constantly collect and store the incident duration data. This study investigates the individual and simultaneous differential effects of the relevant determinants on motorway crash duration probabilities. In particular, it applies parametric Accelerated Failure Time (AFT) hazard‐based models to develop in‐depth insights into how the crash‐specific characteristic and the associated temporal and infrastructural determinants impact the duration. AFT models with both fixed and random parameters have been calibrated on one year of traffic crash records from two major Australian motorways in South East Queensland, and the differential effects of determinants on crash survival functions have been studied on these two motorways individually. A comprehensive spectrum of commonly used parametric fixed parameter AFT models, including generalized gamma and generalized F families, has been compared with random parameter AFT structures in terms of goodness of fit to the duration data, and as a result, the random parameter Weibull AFT model has been selected as the most appropriate model. Significant determinants of motorway crash duration included traffic diversion requirement, crash injury type, number and type of vehicles involved in a crash, day of week and time of day, towing support requirement and damage to the infrastructure. A major finding of this research is that the motorways under study are significantly different in terms of crash durations; such that motorway 1 exhibits durations that are on average 19% shorter compared with the durations on motorway 2. The differential effects of explanatory variables on crash durations are also different on the two motorways. The detailed presented analysis confirms that looking at the motorway network as a whole, neglecting the individual differences between roads, can lead to erroneous interpretations of duration and inefficient strategies for mitigating travel delays along a particular motorway. 相似文献
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作为海上环境保护的专用船舶,深水环保船具有海面溢油回收、应急指挥、油污消除及对外消防等作业能力,主要用于我国深水海域石油勘探开采过程中测试井液/污油水的接收与返送。文章针对深水环保船新型设计,着重介绍船舶性能、动力定位、溢油回收等三大特点。此船舶是国内现有航速最快、主尺度最大、功能最先进、装备最齐全、载运能力最大及回收能力最强的多功能专用船舶,即将服役于东海与南海深水海域。 相似文献
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结合山西省开放式公路收费的实际,确定了适应山西省开放式公路计重收费费率。通过建立开放式公路计重收费数学模型。运用Excel生成不同类型载货车的伪随机样本,设计微调器进行调整,对研究对象采用两种不同方法进行动态仿真。最终实现符合交公路发[2005]492号文件提供的计重收费指导原则的计重费率。 相似文献
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GLOBAL MEASURE ON IMAGE CONTENT 总被引:1,自引:0,他引:1
李介谷 《上海交通大学学报(英文版)》2000,5(2)
IntroductionContent- based image retrieval has been proposedto allow retrieval to be performed on the basis ofa variety of aspects of image content[1] .A chal-lenging problem arises with many imagedatabases,within which queries are posed via vi-sual or pictorial examples.A common visualquery to an image database system would involvefinding all images in the database which containa subimage that is similar to the query image.Such retrievals must be based on embedded con-tent features,such as sh… 相似文献
107.
Experimental investigation on scour development and scour protection for offshore converter platform
Local scour around the offshore converter platform caused by current and wave will lead to the instability of foundation. A series of experiments are performed to investigate the scour development and scour protection of the offshore converter platform. The development and evolution characteristics of the local scour around the gravity based structure foundation under the actions of current flow and wave are analyzed. The results show that the edge scour mainly occurs at the lateral sides of the platform and the scour pits are symmetrical about the centerline of the platform in the streamwise flow direction. The scour depth around the gravity based structure increases with the increase of flow velocity. The inclination and collapse of the platform is observed at α = 90° and U0 = 0.25 m/s. The sand ripples are observed around the gravity based structure under the wave action, and the scour depth increases with the increase of wave height and wave period. Based on the comparisons of different scour protection methods, the combined bionic grass-geotextile-riprap protection has the best scour protection efficiency for the offshore converter platform. 相似文献
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基于GBS的造船综合标准化 总被引:1,自引:1,他引:0
介绍了国际海事标准发展动态以及对我国造船标准化的巨大挑战,阐述了要成为造船强国必须认清差距,重点解决主要问题,提升标准技术含量,并指出了用综合标准化的系统方法发展造船标准是一条提升产业素质的可行道路。 相似文献
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基于RTK五轮仪研制的汽车运动性能试验研究 总被引:13,自引:0,他引:13
利用GPS载波相位RTK技术研制成了汽车道路试验RTK五轮仪。应用该五轮仪进行了汽车的直线和曲线运动性能测试,结果表明可以更精确测取汽车运动性能参数,实现基于动态轨迹测量的汽车运动性能试验评价。 相似文献