面向老龄化社会的常规公交系统问题与对策——基于老年人常规公交出行测量模型

我国已经进入老龄化社会,老年人由于生理特性的衰退、心理特性的改变,导致其搭乘常规公交时的行为特性与需求都与一般中、低龄者不同.因此,对老年人搭乘常规公交出行的需求进行了五点量表式问卷调查,获得老年人搭乘常规公交时感受到的交通环境问题,在对数据进行统计分析、信度检验和因素分析的基础上,建立简单的结构方程模型,模型经过拟合修正后,提取了影响显著的问题因子.最后分析老年人搭乘常规公交出行时的需求,并提出老龄化社会常规公交环境的改善措施.     

Statistical modeling of Electric Vehicle electricity consumption in the Victorian EV Trial,Australia

The market share of Electric Vehicles (EVs), an attractive alternative to conventional vehicles, is expected to exceed 30% of all vehicles by 2033 in Australia. Although the expected EV uptake may place greater burdens on electricity networks, the potential impacts contributed by different EV user categories and vehicle models to peak loads at different times during the day are not well understood. This paper addresses the issue through statistical analysis of the charge events in the Victorian EV Trial in Australia as well as modeling the charging behaviors according to participant categories and vehicle models. The analysis was performed on 4933 charge events that were recorded by both private and public Electric Vehicle Supply Equipment. In total, these events consumed over 33 MW h of energy over 12,170 h by the 178 trial participants, out of which about 70% were household participants while the others were fleet participants. Based on a range of EV uptake scenarios and modeled charging behaviors from the trial, the power demand in the summer of 2032/33 was estimated for all of Victoria. The results of the simulations show that the broad scale uptake of EVs produces a relatively small increase in overall power demand (estimated to be between 5.72% and 9.79% in 2032/33).     

Do social norms regarding carbon offsetting affect individual preferences towards this policy? Results from a stated choice experiment

This study investigates the idea that people’s willingness to offset flight-related carbon emissions is a function of the collective participation rate, which can be regarded as a social norm, towards carbon offsetting. Additionally, we reveal people’s preferences toward two other environmental policies; a baggage allowance and airline eco-efficiency index. A discrete choice experiment is designed and administrated among a sample of air travelers. The results indicate that carbon offsetting generates utility, with people gaining more utility when the collective participation rate is high. Additionally, it was found that the baggage allowance and the eco-efficiency index strongly influenced respondents’ airline choices. People also became more sensitivity towards a baggage allowance and the eco-efficiency label, when the collective offsetting rate was high.     

阀控非对称缸位置系统的非线性建模

针对伺服阀控非对称液压缸系统存在的非线性特性,根据液压系统工作原理,应用功率键合图建模理论,建立了阀控非对称缸位置系统的键合图模型.通过模型仿真及试验结果对比,验证了模型的准确性,为应用各种控制策略改善系统性能提供了理论基础.     

城市轨道交通电气系统网络负荷建模方法研究

城市轨道交通电气系统网络存在分散性、时变性、随机性、多样性和非连续性等多种特性。介绍了几种常用的经典负荷模型结构。针对该电气系统网络系统的特点,采用带有反馈模拟云数据生成器,应用隶属度函数与经典负荷模型相结合理论,提出一种基于窗函数的负荷模型建模方法,并对该方法进行了仿真验证。     

High-resolution numerical relaxation approximations to second-order macroscopic traffic flow models

A novel numerical approach for the approximation of several, widely applied, macroscopic traffic flow models is presented. A relaxation-type approximation of second-order non-equilibrium models, written in conservation or balance law form, is considered. Using the relaxation approximation, the nonlinear equations are transformed to a semi-linear diagonilizable problem with linear characteristic variables and stiff source terms. To discretize the resulting relaxation system, low- and high-resolution reconstructions in space and implicit–explicit Runge–Kutta time integration schemes are considered. The family of spatial discretizations includes a second-order MUSCL scheme and a fifth-order WENO scheme, and a detailed formulation of the scheme is presented. Emphasis is given on the WENO scheme and its performance for solving the different traffic models. To demonstrate the effectiveness of the proposed approach, extensive numerical tests are performed for the different models. The computations reported here demonstrate the simplicity and versatility of relaxation schemes as solvers for macroscopic traffic flow models.     

基于Revit的盾构管片参数化建模应用

为解决传统方法对盾构管片建模重复性工作较多的问题,介绍基于Revit参数化技术,将标准盾构预制管片中的变量参数进行参数化处理,通过修改参数快速生成新的盾构预制管片的方法,且针对盾构管片错缝拼接工作繁琐、拼接位置不准确等问题,采用盾构管片旋转角度参数及盾构管片到参考点距离参数进行参数相关的处理,使盾构管片随距离参数的改变而自动发生相应角度的旋转,从而快速并准确地完成错缝拼接的方法。利用Revit参数化对盾构管片进行建模和错缝拼接的方法,能极大地加快建模的效率和拼装的准确率。该方法成功地应用于上海市虹梅南路盾构隧道管片的设计中,对虹梅南路越江隧道的建设起着重要的作用。     

Multi-axle/articulated bus dynamics modeling: a reconfigurable approach

This paper proposed a unified model including yaw and roll dynamics for any axle or articulation configuration of buses by using a reconfigurable approach. First, all the possible existing configurations of buses are introduced, including the axle/articulation configuration, powertrain configuration, and active chassis control configuration. Consequently, the research is motivated by a key question: how can we develop a unified model that is inclusive and configurable to all of the above bus configurations? To develop the model, three layers of the modeling process are presented step by step. The magic formula and vertical load transfer are discussed to formulate the tyre model. It is noted that the case of the articulated bus is presented in an independent section but how it is included and unified in a general form is also explained. Finally, a modeling validation of axle or articulation configuration cases is performed and the comparative results to high-fidelity models show the feasibility, efficiency, and convenience of the reconfigurable approach. As the crucial feature, the resulting model can be potentially applied to model-based controller design in any buses without reformulating the model. This will greatly benefit the vehicle dynamics control and also future autonomous buses. Although the focus of this paper is buses, the proposed approach actually covers any multi-axle/articulated vehicles, like trucks, tractor-trailers.     

燃燃共同运行功率均衡控制策略研究

采用模块化,变比热的方法在labview平台上建立了燃气轮机动态模型,结合电机扭矩控制实现了燃气轮机特性的模拟。设计了燃燃联合运行负荷平均分配的控制策略,并进行了燃燃联合动力共同带负载的半物理仿真试验,试验结果证实采用本文设计的控制策略能实现负荷平均分配,动态过程比较稳定,设计的控制策略能基本满足要求。