在驾驶席“打坐”——体验特斯拉自动驾驶

人们常说,纪录是用来打破的。我曾经用31小时零4分驾车横穿美国。后来,Ed Bolian打破了这一纪录。而今年早些时候,Carl Reese,Deena Mastracci和几个朋友用特斯拉Model S创造了一项电动汽车横穿美国的纪录。老实说,2006年Polizei车队横穿美国时,我从未想过有天会驾驶一辆96％的时间都在自动驾驶的电动汽车再次横越美国。     

海洋工程深水开发浮式系统的耦合计算方法

当前海洋深水开发所用的浮式平台系统多为浮式船体与柔性系泊系统及立管系统的耦合体,这样,浮式船体与柔性系统之间必将有相互影响及相互作用.由于其整体系统的非线性及动力学特性,势必要求对深水浮式平台系统进行有效的时域耦合分析计算.本文首先简要介绍时域耦合分析的具体问题及解决方法,然后介绍作者近年来开发的HARP(Hull And Riser Program)耦合计算程序.     

Guaranteed prediction and estimation of the state of a road network

The paper presents an algorithm for the prediction and estimation of the state of a road network comprising freeways and arterials, described by a Cell Transmission Model (CTM). CTM divides the network into a collection of links. Each link is characterized by its fundamental diagram, which relates link speed to link density. The state of the network is the vector of link densities. The state is observed through measurements of speed and flow on some links. Demand is specified by the volume of vehicles entering the network at some links, and by split ratios according to which vehicles are routed through the network. There is model uncertainty: the parameters of the fundamental diagram are uncertain. There is uncertainty in the demand around the nominal forecast. Lastly, the measurements are uncertain. The uncertainty in each model parameter, demand, and measurement is specified by an interval. Given measurements over a time interval [0, t] and a horizon τ ? 0, the algorithm computes a set of states with the guarantee that the actual state at time (t + τ) will lie in this set, consistent with the given measurements. In standard terminology the algorithm is a state prediction or an estimate accordingly as τ > 0 or =0. The flow exiting a link may be controlled by an open- or closed-loop controller such as a signal or ramp meter. An open-loop controller does not change the algorithm, indeed it may make the system more predictable by tightening density bounds downstream of the controller. In the feedback case, the value of the control depends on the estimated state bounds, and the algorithm is extended to compute the range of possible closed-loop control values. The algorithm is used in a proposed design of a decision support system for the I-80 integrated corridor.     

Improved theoretical modeling of a cyclone separator as a diesel soot particulate emission arrester

Particulate matter is considered to be the most harmful pollutant emitted into air from diesel engine exhaust, and its reduction is one of the most challenging problems in modern society. Several after-treatment retrofit programs have been proposed to control such emission, but to date, they suffer from high engineering complexity, high cost, thermal cracking, and increased back pressure, which in turn deteriorates diesel engine combustion performance. This paper proposes a solution for controlling diesel soot particulate emissions by an improved theoretical model for calculating the overall collection efficiency of a cyclone. The model considers the combined effect of collection efficiencies of both outer and inner vortices by introducing a particle distribution function to account for the non-uniform distribution of soot particles across the turbulent vortex section and by including the Cunningham correction factor for molecular slip of the particles. The cut size diameter model has also been modified and proposed by introducing the Cunningham correction factor for molecular slip of the separated soot particles under investigation. The results show good agreements with the existing theoretical and experimental studies of cyclones and diesel particulate filter flow characteristics of other applications.     

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虽然多数先进技术应用的目的是改善路网的运行效率和安全性,但目前为止其在提高道路安全性方面的作用并不突出. 例如,可以提供大容量、多方面信息的可变信息板,其设立之初的唯一目的是引导驾驶员的道路行驶. 事实上,这种信息传达装置在不发布路段行驶信息的情况下,还可以发布交通安全信息以改善交通安全状况. 本文选取两种禁止超速信息为研究对象,分析了该信息的发布对于驾驶员态度和路段行驶车速的影响. 对近100名驾驶员进行抽样调查. 测试路段为加拿大埃德蒙顿市和卡尔加里市间2号高速公路. 研究结果表明,本文所选取的两种禁止超速标识对驾驶员态度和行驶车速产生的影响相对较小.     

Planning framework of analytical approaches applied to Zairean transportation

The purpose of the article is to provide an analytical planning framework which includes decision makers, organizations imposing operational and institutional constraints, direct customers and indirect beneficiaries. All these actors have differ-ent, only partially overlapping, interests; this increases the complexity of capital budgeting and imposes limitations on decision-making framework has important implica-tions for project selection, charging and depreciation policies. Although the illus-trations are limited to transport planning, the framework can be easily applied to any sector or country. For example, the English engineering students applied the framework to 18 industries in the U.K.: Auto-diesels, Bass, British Airways, British Gas, British Oxygen, British Petroleum, British Rail, British Steel, British Telecom, East Midland Electricity, Guinness, Imperial Chemical Industries (ICI), Inter-national Computers Limited (ICL), Marks & Spencer, Mercury Communications, National Westminster Bank, Rover and Thames Television (see A. Kelvin, 1993, Increasing student participation in the learning process. Higher Education, 26(4), December, 449-470).     

Grey-Fuzzy Taguchi approach for multi-objective optimization of performance and emission parameters of a single cylinder crdi engine coupled with EGR

The present study attempts to address the challenges of the multiobjective optimization problem of the BSFC-NOx-PM trade-off paradox of an existing diesel engine by harnessing the synergetic benefit of PM and BSFC reduction through CRDI operation and simultaneous NOx reduction by EGR application. Load, FIP and EGR were chosen as the input parameters while NOx, PM and BSFC were the response variables. In order to reduce the experimental effort, the Taguchi L₁₆ orthogonal array technique was employed to obtain the corresponding values of the response variables. The grey relational analysis coupled with fuzzy logic has been employed as the optimization routine. The optimal combination of the input parameters corresponding to the calibrated values of the response variables were obtained by employing the Grey-Fuzzy Grade and S-N ratio strategy as a performance index. The computed optimal combination so obtained were further validated through actual experimentation. EGR was found to be the most influencing factor in the present optimization endeavour. The study also established that the Grey-Fuzzy-Taguchi method was not only comparable but superior to the Grey-Taguchi method usually employed for such optimization studies.