Characterization of Dynamic Vehicle Stability Using Two Models of the Human Pilot Behaviour

This article deals with a study of the stability of the vehicle/pilot system for two different models of human operator behaviour. These models, are the outcome of various.approximations of the precision model for single loop compensatory situations. The vehicle is represented with two degrees of freedom and the pilot is assumed to respond to the lateral displacement and to the lateral velocity with a time delay. The properties of these resulting systems are presented and it is observed that, for any given forward visibility, a critical velocity defines a domain of controllability from a domain of uncontrollability. Furthermore this critical velocity is shown independant of the vehicle/ pilot parameters and may be considered as a possible vehicle safety criterion.     

季冻区隧道离壁式波纹钢板保温套衬及其保温效果研究北大核心CSCD

为防治季冻区隧道中频繁出现的冻害问题,提出一种新型离壁式波纹钢板保温套衬,该套衬具有施工简便、防水性能可靠、防止混凝土掉块、提高聚氨酯使用寿命等优势,采用数值仿真对季冻区施作离壁式波纹钢板保温套衬隧道的温度场及其保温效果进行研究。结果表明:季冻区隧道施作新型离壁式波纹钢板保温套衬后,阻隔了寒冷空气对衬砌结构的影响,围岩正温区范围增大,隧道冻结线由距衬砌0.48 m围岩处前移至保温套衬,有效防止了季冻区隧道冻害的发生;季冻区隧道贴壁式聚氨酯保温层的保温效果为89.90%~96.43%,新型离壁式波纹钢板保温套衬的保温效果为101.94%~107.14%,离壁式波纹钢板保温套衬的保温效果要优于贴壁式聚氨酯保温层。     

Evaluation of transit operations: data applications of Tri-Met's automated Bus Dispatching System

In this paper, archived Automatic Vehicle Location and Automatic Passenger Counter data are used to evaluate actual bus running time variation in relation to scheduled service for Tri-Met, the transit provider for the Portland, Oregon metropolitan area. Given observed variation in running times, scheduled recovery times are found to be generally (though not universally) excessive. This results in an under-investment of resources in revenue service relative to non-revenue service. Analysis of trip level data reveals that bus operators are an important source of running time variation after controlling for such factors as route design, time of day and direction of service, and passenger activity.     

An application of shock wave theory to traffic signal control

A real time control policy minimizing total intersection delays subject to queue length constraints at an isolated signalized intersection is developed in this paper. The policy is derived from a new traffic model which describes the simultaneous evolution of queue lengths of two conflicting traffic streams, controlled by a traffic light, in both time and space. The model is based on the examination of shock waves generated upstream of the stop lines by the intermittent service of traffic at the signal. The proposed policy was tested against the existing pre-timed control policy at a high volume intersection and it was found superior, especially when demands increase well above the saturation level.     

Pedestrianisation: London's Oxford Street experiment

Oxford Street in London, is the capital's principal shopping street and famous throughout the Western World; it is also the most obvious route from the city of London to the West, the Midlands and the North of England.The conflict between its twin roles of shopping centre and major traffic route was demonstrated in its accident record which put Oxford Street top of the list of accident blackspots in London, whilst its location in the most fashionable area of London make the costs of new road construction prohibitive.A comprehensive accident analysis defined the pedestrian/vehicle conflict by time and place and facilitated the detail design of a limited traffic ban with associated rerouting.Considerable uncertainties in prediction of the resulting traffic conditions, in the absence of data on demand elasticity, dominated the design of the experiment and led to the inclusion of an avert chaos policy. Traffic predictions which included details of the probable manner in which congestion would spread were assisted by a new network simulation model developed by one of the authors and described here.The report outlines the history of the experiment from conception to implementation (in record time) and reports some early and generally encouraging results. On the strength of which the Greater London Council has confirmed the scheme (August 1973) and has announced plans for its extension to the remaining half of Oxford Street — from Oxford Circus to St. Giles' Circus — which still carries the full weight of traffic.Previously undertaking doctoral research at Imperial College, London.     

Nudging people towards more sustainable residential choice decisions: an intervention based on focalism and visualization

Transportation - There have been numerous behavior change studies focused on sustainable travel mode choices. In this study we focused on the residential choices that in turn influence travel...     

The Random Vibration of a Nonuniform Cantilever Beam with Concentrated Mass

The random vibration of a nonuniform cantilever beam with a concentrated mass at its end, is studied as a simple model of the suspension spring of a motor vehicle. The spectral response of the displacement of the concentrated mass is obtained when the beam is subjected to the random motion of the support. The conditions for the validity of the single degree approximation is also discussed.     

Novel stability control strategy for distributed drive electric vehicle based on driver operation intention

In this paper, a novel direct yaw control method based on driver operation intention for stability control of a distributed drive electric vehicle is proposed. It was discovered that the vehicle loses its stability easily under an emergency steering alignment (EA) problem. An emergent control algorithm is proposed to improve vehicle stability under such a condition. A driver operation intention recognition module is developed to identify the driving conditions. When the vehicle enters into an EA condition, the module can quickly identify it and transfer the control method from normal direct yaw control to emergency control. Two control algorithms are designed. The emergency control algorithm is applied to an EA condition while the adaptive control algorithm is applied to other conditions except the EA condition. Both simulation results and real vehicle results show that: The driver module can accurately identify driving conditions based on driver operation intention. When the vehicle enters into EA condition, the emergent control algorithm can intervene quickly, and it has proven to outperform normal direct yaw control for better stabilization of vehicles.     

新型快餐盒生物降解性能试验方法研究

通过固体培养微生物侵蚀试验、液体培养微生物侵蚀试验、降解过程中纤维素酶活性测定、纤维素酶侵蚀试验和降解过程中 Ｃ Ｏ２ 生成体积分数的测定等试验结果分析，认为固体培养微生物侵蚀试验、纤维素酶侵蚀试验及 Ｃ Ｏ２ 生成量测定试验可用于评价新型快餐盒生物降解性能。