区分障碍物特性的客车乘客疏散模型与分析

近年来,疏散性能评估已成为客车车厢设施布局及设计流程中的必要环节.考虑狭长通道下障碍物特性对人员疏散影响显著,引入感知域概念,刻画疏散人员翻越座椅等行为决策特性;进一步引入一类多值函数扩充元胞状态集合,量化障碍物的可翻越特性,建立障碍物模型,模拟紧急状态下人员无序疏散行为;为对模型结果验证分析,建立基本模型,构建其与AnyLogic®均可模拟的基本场景,在此场景下对二者模拟结果交叉验证.模拟分析结果及结论是,移动规则合理有效,结合障碍物模型并考虑可翻越障碍物影响的模拟结果是可信的;发现N k O -tk evac 曲线与此情形下的疏散动画具有一定的时空关联性,可为车体设计提供进一步参考;此外,随疏散人员感知域的增大,疏散时间逐渐减小.     

Spatial variation of roadside C2–C6 hydrocarbon concentrations during low wind speeds: Validation of CALINE4 and COPERT III modelling

The CALINE4 model is widely used to predict the effect of vehicle emissions on ambient concentrations close to roadways. It requires an evaluation of the rate at which different air pollutants are emitted by vehicles, taking into account things such as vehicle flow, velocity, type and age. For Europe the databases of the COmputer Program to calculate Emissions from Road Transport (COPERT) are combined with local vehicle details to obtain site-specific emission factors for dispersion modelling. The ability of CALINE4 to predict the spatial variation of hydrocarbon concentrations downwind of a motorway is assessed, as is the accuracy of COPERT III composite emission factors for several hydrocarbon compounds. The concentrations of seven traffic-associated compounds is found at three locations downwind and upwind of a motorway. Modelled and measured background-corrected downwind concentrations are compared on three bases: daily peak hour concentrations, mean concentrations, and a set of model evaluation parameters.     

基于Excel的红绿灯仿真控制决策

电子表格Excel具有强大的计算功能,它是一种可描述问题、建立模型、处理数据与求解的有效工具.汽车行驶到十字路口,受红绿灯控制,产生等待时间.利用Excel对此进行计算机仿真模拟,比较不同控制参数对控制目标的影响,可以找到相对较佳的方案.     

模糊评价法在TDM方案决策中的应用

对近期提出的北京市交通需求管理(TDM)措施进行不同实施力度的组合,得出了若干组合方案;建立了交通需求管理政策方案评价指标体系,运用模糊统计法实现对非定量指标隶属度的确定,按效益型指标和成本型指标对定量指标分别确定其隶属度;通过专家调查法确定了各评价指标和评价准则的权重向量;最后利用多级模糊评价综合方法进行方案比选,得出最佳方案。本文所使用的方法和结果可以为交通需求管理政策评价、决策提供参考。     

Validating the Passenger Traffic Model for Copenhagen

The paper presents a comprehensive validation procedure for the passenger traffic model for Copenhagen based on external data from the Danish national travel survey and traffic counts. The model was validated for the years 2000–2004, with 2004 being of particular interest because the Copenhagen Metro became operational in autumn 2002. We observed that forecasts from the demand sub-models agree well with the data from the 2000 national travel survey, with the mode choice forecasts in particular being a good match with the observed modal split. The results of the 2000 car assignment model matched the observed traffic better than those of the transit assignment model. With respect to the metro forecasts, the model over-predicts metro passenger flows by 10–50%. The wide range of findings from the project resulted in two actions. First, a project was started in January 2005 to upgrade the model’s base trip matrices. Second, a dialog between researchers and the Ministry of Transport has been initiated to discuss the need to upgrade the Copenhagen model, e.g. a switching to an activity-based paradigm and improving assignment procedures.     

Farm tractor models for research and development purposes

The modelling problems related to the simulation of the dynamics of farm tractors are dealt with. The aim is to develop reliable mathematical models to speed-up the research and development activities in which farm tractors and their sub-systems (driveline, steering and suspension system, etc.) are to be conceived and designed. Two models of farm tractors have been developed. The first model is based on a proprietary software, able to quickly simulate the motion of a vehicle on smooth or rough soil. The second model has been developed by the commercial software ADAMS/Car^®, which allows to model complicated transmission and suspension systems. In both of the two models, the tyres, the transmission system, the suspension system, the steering system, the engine and the body inertia are carefully described mathematically. Both of the two models are defined in a parametric way. Particular attention has been devoted to the measurements of the tyre characteristic and of the inertia parameters of the farm tractor body. For the measurement of tyre characteristics, a new instrumented wheel hub has been used. The accurate measurement of both the tyre characteristic and body inertia tensor has allowed a good agreement between measured and computed time histories referring to a number of validation manoeuvres performed either on-road or off-road. The derived farm tractor models could simulate the working conditions of a generic farm tractor while hauling a plough or while running at a relatively high speed on a rough soil or while steering on a sloped, soft surface.     

供应链企业业务外包决策模型研究

为适应供应链企业业务外包决策的需要，建立了供应链企业业务外包模型，分析了供需双方独立决策时各自的产量决策和生产能力投资决策．讨论了基于价格合同的外包形式，建立了2个企业进行业务外包决策的两阶段动态博弈模型，并证明了其存在子博弈精练Nash均衡．     

重载电力机车钩缓系统建模研究

针对不同类型重载电力机车钩缓系统建模方法进行研究,提供了非线性迟滞特性缓冲器及两种典型重载电力机车钩缓系统的建模方法,建立了由4节机车及1节简化货车组成的列车模型。以DFC-E100及13A/QKX-100钩缓系统为例,通过列车仿真验证了建模方法的合理性与准确性。研究结果表明,文中所建立的钩缓系统模型能够较好地反映重载电力机车钩缓系统实际运行状态,仿真结果重现了两种钩缓系统在线路试验中表现出的稳定性差异现象。     

基于UML工作流模型的应用研究

分析了工作流模型的组成,根据统一建模语言的特点,形式化定义了为工作流过程建模的UML活动图结构以及建模规则,给出一个应用实例来描述建模过程并对模型作了详细分析。     

Heavy-duty vehicle modelling and longitudinal control

This paper addresses modelling, longitudinal control design and implementation for heavy-duty vehicles (HDVs). The challenging problems here are: (a) an HDV is mass dominant with low power to mass ratio; (b) They possess large actuator delay and actuator saturation. To reduce model mismatch, it is necessary to obtain a nonlinear model which is as simple as the control design method can handle and as complicated as necessary to capture the intrinsic vehicle dynamics. A second order nonlinear vehicle body dynamical model is adopted, which is feedback linearizable. Beside the vehicle dynamics, other main dynamical components along the power-train and drive-train are also modelled, which include turbocharged diesel engine, torque converter, transmission, transmission retarder, pneumatic brake and tyre. The braking system is the most challenging part for control design, which contains three parts: Jake (engine compression) brake, air brake and transmission retarder. The modelling for each is provided. The use of engine braking effect is new complementary to Jake (compression) brake for longitudinal control, which is united with Jake brake in modelling. The control structure can be divided into upper level and lower level. Upper level control uses sliding mode control to generate the desired torque from the desired vehicle acceleration. Lower level control is divided into two branches: (a) engine control: from positive desired torque to desired fuel rate (engine control) using a static engine mapping which basically captures the intrinsic dynamic performance of the turbo-charged diesel engine; (b) brake control: from desired negative torque to generate Jake brake cylinder number to be activated and ON/OFF time periods, applied pneumatic brake pressure and applied voltage of transmission retarder. Test results are also reported.