新建结构与运营地铁车站接驳关键技术

以深圳地铁新建3号线老街站换乘综合体与运营地铁车站接驳工程为实例,对运营车站临时加固防护、分部切割既有结构、新旧结构接驳等关键技术展开论述。提出运用金刚石绳锯与金刚石水钻相结合的一种静力切割工艺,很好地解决了该工程作业环境复杂、技术要求高、风险大等难题,安全、高效地完成了新建结构与运营地铁车站接驳工程。     

A theoretical foundation for the relationship between generalized origin–destination matrix and flow matrix based on ordinal graph trajectories

This paper shows the relationship between flow, generalized origin–destination (OD), and alternative route flow from a set of ordinal graph trajectories. In contrast to traffic assignment methods that employ OD matrix to produce flow matrix, we use ordinal trajectory on a network graph as input and produce both the generalized OD matrix and the flow matrix, with the alternative and substitute route flow matrices as additional outputs. By using linear algebra‐like operations on matrix sets, the relationship between network utilization (in terms of flow, generalized OD, alternative route flow, and desire line) and network structure (in terms of distance matrix and adjacency matrix) are derived. Copyright © 2012 John Wiley & Sons, Ltd.     

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高速铁路为人们提供了一种高效的运输方式.本文借鉴弹性系数法的相关理论,首先运用广义费用函数测算样本中高铁开通前后两地区综合客运成本的变化,结合两地区高铁开通前后客运量的变化得到了运输成本弹性系数,用于衡量两地区对于高铁开通的迫切性程度,从而在另一个层面衡量高铁建设的可行性.然后根据运输经济学及新经济地理学的相关理论,从人口、距离、人均GDP差异、平均人均GDP和产业结构相似度5个维度对样本的运输成本弹性系数进行建模,运用神经网络的方法来拟合其对运输成本弹性系数的影响情况,并以此为依据来测算北京市和张家口市对即将开通的京张高铁的迫切性程度.     

Impacts of trade related sustainability strategies on freight transportation: Modelling framework and application for France

The circular and functional economies are being presented in the literature as potential strategies for future sustainable societies. In terms of the consequences for supply chains, they will promote a much more dispersed and diversified, local and network based usage of goods than the current economy, which is comparatively linear, concentrated, long distance oriented and scale economy based. A gap in the literature is the assessment of the effects of these systems on freight transport flows. In our paper, we present a first attempt at estimating this impact using freight transport scenario building and quantitative modelling. In order to translate the main parameters that characterize these systems into factors determining freight transportation volumes, we develop a framework based on a typology of goods categories describing functional and spatial proximity between producers and consumers. In order to simulate changes in the economy, we develop scenarios for the shifting of goods from one category to another and, additionally, include internalization policies that should guide their realization. We calculate the impacts on freight flows using a new interregional transport model for France that includes distribution chains and produces estimates of external costs of transport. Our results show that circular and functional economies could lead to a 2–5% reduction of air pollutant emissions and up to a 14–26% reduction if combined with the internalization of external costs. The scenario with ongoing mass production for differentiated demand is found to lead to a 5% increase of environmental impacts compared to the baseline.     

基于多维信息特征分析的驾驶人认知负荷研究

准确评估驾驶人认知负荷水平，对于深入研究驾驶人行为特性，改善驾驶安全性具有重要意义。现有的驾驶人认知负荷分类方法，大多基于心电、脑电等生理信息和车辆信息，由于特征选择上的单一性，导致驾驶人认知负荷分类模型的分类精度不高。设计基于跟驰场景的不同认知负荷N-back次任务试验，通过采集受试者的生理信号和车辆信号，结合NASA_TLX主观评分和机器学习算法，提出了基于多维信息特征融合的驾驶人认知负荷分类方法。研究表明：基于生理信息和车辆信息的多维信息特征认知负荷分类方法，其精度显著高于传统的基于生理信息的认知负荷分类方法，以多维信息特征为输入，随机森林法以其稳定性好、抗过拟合能力强的特点，表现出优异的分类效果，相比神经网络和支持向量机，具有最高的平均分类精度。     

基于“1+3”的复合型人才课程体系的探索与实践——以新能源汽车技术专业为例

当前时期,针对复合型人才教学体系的创新,应当有对性地构建起更加完善的人才培养体系,并做好对于学生的专业性知识技能和专业性职业技能优化培养。结合现阶段的新能源汽车技术专业培养,要针对把握性教学标准和教学要求,做好有效性的更新和完善,本文主要结合基于"1+3"的复合型人才课程体系的探索与实践展开了研究分析。     

Daily activity pattern recognition by using support vector machines with multiple classes

The focus of this paper is to learn the daily activity engagement patterns of travelers using Support Vector Machines (SVMs), a modeling approach that is widely used in Artificial intelligence and Machine Learning. It is postulated that an individual’s choice of activities depends not only on socio-demographic characteristics but also on previous activities of individual on the same day. In the paper, Markov Chain models are used to study the sequential choice of activities. The dependencies among activity type, activity sequence and socio-demographic data are captured by employing hidden Markov models. In order to learn model parameters, we use sequential multinomial logit models (MNL) and multiclass Support Vector Machines (K-SVM) with two different dependency structures. In the first dependency structure, it is assumed that type of activity at time ‘t’ depends on the last previous activity and socio-demographic data, whereas in the second structure we assume that activity selection at time ‘t’ depends on all of the individual’s previous activity types on the same day and socio-demographic characteristics. The models are applied to data drawn from a set of California households and a comparison of the accuracy of estimation of activity types and their sequence in the agenda, indicates the superiority of K-SVM models over MNL. Additionally, we show that accuracy in estimating activity patterns increases using different sets of explanatory variables or tuning parameters of the kernel function in K-SVM.     

“1+X”证书制度下的汽车检测与维修专业“三教”存在问题研究

在教学过程中,"师资,教材,教法"是基本内容,教学质量指标也受到影响。本文以新能汽车检验维修专业为例,对职教二十条进行了分析。职业教育"三教一体化"改革的重要性,同时,针对教师,教材和教学方法等问题提出了切实可行的改革思路,仅供相关人员参考。     

高疲劳抗力钢桥面板的疲劳问题Ⅱ：结构体系抗力

为了深刻认识高疲劳抗力钢桥面板的疲劳特性，准确评估其结构体系的疲劳抗力，基于等效结构应力建立了考虑焊接微裂纹对钢桥面板疲劳性能劣化效应的结构体系疲劳抗力评估方法，并通过疲劳试验对所建立的评估方法进行了验证。在此基础上采用所建立的结构体系疲劳抗力评估方法对高疲劳抗力钢桥面板的疲劳开裂模式、疲劳抗力及其影响因素等相关关键问题进行系统研究。研究结果表明：焊接微裂纹的存在会显著降低钢桥面板的疲劳性能，导致主导疲劳开裂模式发生迁移；结构体系设计参数对纵肋与顶板双面焊构造细节和纵肋与横隔板新型交叉构造细节疲劳性能的影响有显著区别，其中纵肋与顶板双面焊构造细节的疲劳性能主要对顶板厚度的变化较为敏感，其疲劳性能随着顶板厚度的增加而显著提升，而纵肋与横隔板新型交叉构造细节的疲劳性能同时受多个参数的影响，其疲劳性能随着顶板厚度、横隔板厚度和纵肋高度的增大而提升，随着横隔板间距和纵肋底板与横隔板之间焊缝长度的增大而降低；传统钢桥面板的主导疲劳开裂模式为纵肋腹板与横隔板交叉构造细节围焊焊趾开裂，高疲劳抗力钢桥面板的主导疲劳开裂模式为纵肋底板与横隔板交叉构造细节纵肋焊趾开裂；相对于传统正交异性钢桥面板，高疲劳抗力钢桥面板结构实现了主导疲劳开裂模式的迁移，疲劳性能显著提高。