基于图像点云空间测距算法的隧道初期支护整体变形监测技术研究与应用

为快速、准确获取施工隧道初期支护整体及局部变形信息,基于计算机视觉算法获取的隧道初期支护图像稀疏点云和密集点云数据,结合基于Hausdorff 距离的整体模型和基于最小二乘拟合平面的局部模型各自的特点,提出将两者相结合的图像点云空间测距算法。该方法可为每个点保留整体模型和局部模型分别计算的距离值中的较小值,解决前者对点云密度要求高以及后者局部拟合平面存在较大偏差问题,实现多期隧道图像点云直接比较分析,简化计算步骤和后处理过程,提高隧道初期支护变形监测速率和精度。通过对云南香丽高速公路白岩子隧道进口左线ZK61+990~ +994 段初期支护整体变形的监测分析,结果表明: 该技术能直观、可视化反映隧道初期支护整体变形情况,计算结果准确、可靠。     

Consumer preferences for alternative fuel vehicles: A discrete choice analysis

This paper analyzes the potential demand for privately used alternative fuel vehicles using German stated preference discrete choice data. By applying a mixed logit model, we find that the most sensitive group for the adoption of alternative fuel vehicles embraces younger, well-educated, and environmentally aware car buyers, who have the possibility to plug-in their car at home, and undertake numerous urban trips. Moreover, many households are willing to pay considerable amounts for greater fuel economy and emission reduction, improved driving range and charging infrastructure, as well as for enjoying vehicle tax exemptions and free parking or bus lane access. The scenario results suggest that conventional vehicles will maintain their dominance in the market. Finally, an increase in the battery electric vehicles’ range to a level comparable with all other vehicles has the same impact as a multiple measures policy intervention package.     

Modeling the effects of traveler information on freeway origin–destination demand prediction

The primary focus of this research is to develop an approach to capture the effect of travel time information on travelers’ route switching behavior in real-time, based on on-line traffic surveillance data. It also presents a freeway Origin–Destination demand prediction algorithm using an adaptive Kalman Filtering technique, where the effect of travel time information on users’ route diversion behavior has been explicitly modeled using a dynamic, aggregate, route diversion model. The inherent dynamic nature of the traffic flow characteristics is captured using a Kalman Filter modeling framework. Changes in drivers’ perceptions, as well as other randomness in the route diversion behavior, have been modeled using an adaptive, aggregate, dynamic linear model where the model parameters are updated on-line using a Bayesian updating approach. The impact of route diversion on freeway Origin–Destination demands has been integrated in the estimation framework. The proposed methodology is evaluated using data obtained from a microscopic traffic simulator, INTEGRATION. Experimental results on a freeway corridor in northwest Indiana establish that significant improvement in Origin–Destination demand prediction can be achieved by explicitly accounting for route diversion behavior.     

汽车行业工业APP云平台设计架构分析

随着工业互联网技术的蓬勃发展,工业APP云平台成为国内外企业争相研究的热点领域。但目前在汽车行业,国内还缺少一个统一的工业APP云平台进行资源的整合和管理。同时大量工程经验知识缺乏数字化的继承,制约了汽车行业更好更快地发展。对汽车行业工业APP云平台设计架构进行分析,设计了云平台的整体功能架构,简要介绍了平台各层级的功能实现以及平台架构特点,对云平台构建过程中的OpenStack设计架构和微服务架构进行分析,为云平台的实现提供了重要技术手段。汽车行业工业APP云平台建设对汽车行业数字化改革具有重要参考意义。     

Real-time models for wheels and tyres in an object-oriented modelling framework

This article presents models for wheels and tyres in the application field of real-time multi-body systems. For this rather broad class of applications it is difficult to foresee the right level of model complexity that is affordable in a specific simulation. Therefore we developed a tyre model that is adjustable in its degree of complexity. It consists of a list of stepwise developed sub-models, each at a higher level of complexity. These models include semi-empirical equations. The stepwise development process is also reflected in the corresponding implementation with the modelling language Modelica. The final wheel model represents a supermodel and enables users to select the right level of complexity in an unambiguous way.     

一种基于激光与视频信息时空数据融合的行人检测方法

针对城市交通行人安全问题,本文提出了一种基于激光与视频数据融合的行人检测方法.通过激光与视频数据空间和时间上的融合,将激光数据映射到图像坐标;在激光聚类过程中,采用K-means 聚类算法对激光云点进行聚类分析,然后运用行人宽度模型提取候选行人区域;在基于图像的行人检测过程中,选取头肩、躯干以及腿部人体特征部位,采用Haar-like 特征集和Boosting 算法进行训练,得到部位检测器;最后,基于贝叶斯决策的组合策略对候选行人区域进行有效判定.实验结果表明,本文所述算法有较好的检测精度和实时性能.     

高压共轨柴油机燃烧与排放模型的研究

利用高速闪光摄影技术,对高压喷射喷雾体空间发展规律进行了试验分析,提出了一个计算高压喷射喷雾体发展的数学公式;在正确描述高压燃油喷雾的基础上,建立了一个能预测高压共轨柴油机性能和排放的准维燃烧模型,此模型改进了燃油喷射模型及碳烟的生成与氧化模型,考虑到燃烧区的区间传热和缸内工质的对流辐射传热,对一台高压共轨柴油机进行了仿真计算。计算与试验结果对比分析表明,改进后的燃烧与排放模型能较好地反映缸内各区的燃烧与排放情况。     

城市轨道交通自主可控云平台业务系统迁移探析

城市轨道交通云平台对国外产品依存度高,关键环节存在"卡脖子"风险.通过分析该领域的现状,提出相应的解决方案,阐述城轨自主可控云平台的模型,讨论城市轨道交通业务系统向自主可控云平台迁移的可行性及评估方法,详细介绍迁移原则、迁移流程、资源规划以及中间件、数据库、应用等具体的迁移实施路径及典型案例,为解决城市轨道交通云平台面...     

彩色图像中基于几何不变性的数字水印

常规的数字水印算法对几何攻击无能为力,水印算法对几何攻击的鲁棒性被认为是数字水印技术走上实际应用的一个关键点.文中通过对普通的基于几何不变性数字水印算法的分析,提出了一种彩色图像中基于几何不变性的数字水印的嵌入及检测过程,并通过一系列实验证明了该数字水印算法具有很高的抗几何攻击(旋转、缩放等)特性,即提高了鲁棒性.     

基于不等时距离散灰色预测模型的软土地基沉降分析

分别采用线性插值、三次样条插值两种方法,用MATLAB语言编制程序将不等时距序列转化为等时距序列,采用离散灰色预测模型来进行沉降预测.