GIS技术在高速公路监控系统中的实践应用

本文介绍了GIS在高速公路系统中的基本应用,阐述了GIS技术应用于高速公路系统的基本功能、总体架构和相关的系统要求.     

沥青混合料抗拉性能试验研究及力学特性分析

沥青混合料的抗拉性能是表征其低温与疲劳性能的重要指标。本文针对半圆弯曲试验(SCB)与劈裂试验(IDT)建立三维非线性有限元模型,对两种试验方法的受力特点与破坏模式进行数值模拟,并利用室内试验进行验证。结果表明:两试验中试件的力学响应规律明显不同;半圆弯曲试验试件主要承受拉应力,劈裂试验试件内出现压缩、拉伸、剪切多种受力模式交织现象;非轴对称受力时,劈裂试件的应力响应更为复杂,不能充分体现间接拉伸的目的。相比较而言,半圆弯曲试验更能模拟沥青混凝土路面的层底受拉状况。     

基于单总线温度测控系统的前端拓扑网络设计

温度测控系统的前端模块的设计基于单总线（1-Wire Bus）技术,利用数字温度传感器DSl8820构建成1-Wire树型拓扑网络,最大限度地减少单片机的硬件资源占用、软件设计中采用二叉树搜索算法自动完成整个网络的器件搜索．系统设计了完善的上下位机间的通讯协议来保证温度采集的数据的传输的可靠性和准确性,为上位机控制系统提供实时、准确的数据．     

改进的灰色GM(1,1)模型在滑坡预测中的应用

滑坡形成机制复杂其变形受多种因素影响,具有相当的模糊性和灰色不确定性,因而利用灰色预测模型对滑坡进行预测将是一条有效的途径．在介绍了灰色预测的基本原理及其精度检验方法后,针对传统灰色GM（1,1）模型中背景值的取法,提出了一种自动寻优定权的改进措施,通过实例对比分析,表明其预测精度将得到有效提高．     

1+X证书制度在汽车专业领域试点案例

文章针对1+X证书制度在高职汽车专业领域在人才培养模式创新、课证融通、推进“三教改革”、实训室和考核站点建设介绍了自己的实践经验和取得的阶段性成果,对高职汽车专业领域1+X试点具有一定借鉴意义。     

掺Sasobit(R)的温拌沥青混合料路用性能试验研究

温拌沥青混合料是一种节能环保型路面新材料,在室内对掺Sasobit(R)添加剂的温拌沥青混合料的路用性能与普通热拌沥青混合料进行了对比试验研究,结果显示: 掺Sasobit(R)的温拌沥青混合料的拌和与压实温度比普通热拌沥青混合料降低30 ℃时,具有与普通热拌沥青混合料相同甚至更好的路用性能,具有明显的经济和社会效益;拌和与压实温度的降低,混合料发生水损害的可能性会增加,建议采用添加抗剥落剂等方法来改善掺Sasobit(R)的温拌沥青混合料的水稳定性;此外,Sasobit(R)掺量过多会对混合料低温抗裂性能有不利影响.     

Mixed manual/semi-automated traffic: a macroscopic analysis

The use of advanced technologies and intelligence in vehicles and infrastructure could make the current highway transportation system much more efficient. Semi-automated vehicles with the capability of automatically following a vehicle in front as long as it is in the same lane and in the vicinity of the forward looking ranging sensor are expected to be deployed in the near future. Their penetration into the current manual traffic will give rise to mixed manual/semi-automated traffic. In this paper, we analyze the fundamental flow–density curve for mixed traffic using flow–density curves for 100% manual and 100% semi-automated traffic. Assuming that semi-automated vehicles use a time headway smaller than today’s manual traffic average due to the use of sensors and actuators, we have shown using the flow–density diagram that the traffic flow rate will increase in mixed traffic. We have also shown that the flow–density curve for mixed traffic is restricted between the flow–density curves for 100% manual and 100% semi-automated traffic. We have presented in a graphical way that the presence of semi-automated vehicles in mixed traffic propagates a shock wave faster than in manual traffic. We have demonstrated that the presence of semi-automated vehicles does not change the total travel time of vehicles in mixed traffic. Though we observed that with 50% semi-automated vehicles a vehicle travels 10.6% more distance than a vehicle in manual traffic for the same time horizon and starting at approximately the same position, this increase is marginal and is within the modeling error. Lastly, we have shown that when shock waves on the highway produce stop-and-go traffic, the average delay experienced by vehicles at standstill is lower in mixed traffic than in manual traffic, while the average number of vehicles at standstill remains unchanged.     

连续小箱梁桥地震响应分析

以太原市南沙河高架桥工程为例,简要介绍了连续小箱梁桥抗震分析在实际工程设计中的应用,以供今后类似工程计算参考。     

The environmental impact of distribution to retail channels: A case study on packaged beverages

This study aims to quantify the environmental impact of two retail distribution networks and offer consumers a channel that is more beneficial to the environment. The environmental impact of replenishing the packaged beverages sold in convenience stores (CVSs) and hypermarkets is assessed using the streamlined life-cycle assessment (LCA) approach. In this study, the life-cycle impact assessment (LCIA) for packaged beverages up to the point of sale illustrates the distribution-level environmental impacts of truck transportation. The matched-pair t-test shows that the environmental impacts of transporting 1800 cartons of 24-pack/10 oz. beverages to be sold in Carrefour and 7-11 stores is different at a significance level of 0.1. The transport-focused LCA is used to improve the understanding and compare the environmental characteristics of the two distribution and retail systems. This study constitutes a vehicle for communicating to both internal and external stakeholders the environmental profiles of distributing the same product sold through two retail channels.     

Forecasting short-term subway passenger flow under special events scenarios using multiscale radial basis function networks

Reliable and accurate short-term subway passenger flow prediction is important for passengers, transit operators, and public agencies. Traditional studies focus on regular demand forecasting and have inherent disadvantages in predicting passenger flows under special events scenarios. These special events may have a disruptive impact on public transportation systems, and should thus be given more attention for proactive management and timely information dissemination. This study proposes a novel multiscale radial basis function (MSRBF) network for forecasting the irregular fluctuation of subway passenger flows. This model is simplified using a matching pursuit orthogonal least squares algorithm through the selection of significant model terms to produce a parsimonious MSRBF model. Combined with transit smart card data, this approach not only exhibits superior predictive performance over prevailing computational intelligence methods for non-regular demand forecasting at least 30 min prior, but also leverages network knowledge to enhance prediction capability and pinpoint vulnerable subway stations for crowd control measures. Three empirical studies with special events in Beijing demonstrate that the proposed algorithm can effectively predict the emergence of passenger flow bursts.