Macroscopic location models revisited

Recent developments in residential location choice models have considered the individual as the basic unit of analysis and have attempted to model the actual choice process used by individuals in selecting residential location sites. This paper demonstrates that the choice model derived from these studies is a more general form of many macroscopic models of location used in the past. The prime difference between the two classes of model is seen to be the much wider range of factors and geographic settings which can be accounted for in disaggregate behavioural models of residential location choice.     

) and annual payments (a) is a follows:

Modern management techniques are slowly but surely being introduced aslo in shipping management. Large sections of the industry practises strategic management at various levels in the firm. This paper outlines a method for deciding chartering strategies in the international bulk shipping industry. A well known risk/return model is tailored to transportation contracts in the shipping industry. The model delineates a set of optimally defined transportation contracts that may serve as a basis for the shipowner's strategic decisions. The strategies and elements of strategies suggested by the model have historically been practised by a number of successful shipowners. An important conclusion of the paper is that no second best problems exists and hence movement towarts the optimal solution is advocated even if such a solution cannot or will not be reached. Additionally, the paper provides an organized way of crafting, analysing and applying chartering strategies where the outcomes can be clearly defined and analysed based on well known statistical concepts and theories.     

Dense network traffic models,travel time reliability and traffic management. Ii: Application to network reliability

This paper is the second of a pair of papers discussing two main themes concerning dense network modelling. These themes are: (1) the changing nature of traffic management technology and the underlying objectives behind traffic management practice, and (2) the use of measures of network reliability in models, especially as an element of the evaluation of alternative network configurations. This paper develops and applies the second theme, the use of network reliability concepts in the evaluation of traffic networks, through consideration of variations in travel times, distinction between local street and arterial road networks, and the definition and application of a set of reliability indices that may be used to study different trip movements in a network. It indicates how these indices may be used in appraising different traffic management plans for a dense network of local streets and arterial roads, using a case study application.     

Public transport policy in Canada and the United States: Developing political commitment from the federal government

The United States federal government has been involved in public transport funding for over 40 years, whereas in Canada the federal government has little history of urban public transport policy. In that context, over the past 10 years, Canada has made significant progress in developing new federal commitments for public transport. Critical as these developments have been, however, they do not represent a true National Transit Strategy, which needs to be permanent, predictable and comprehensive. This claim is supported by economic analysis which suggests that Canadian government investment in transit is significantly below the optimal level.     

基础设计中的可靠度评估

阐述基于可靠度理论的基础设计的评估。首先总结具有结构抗力和荷载效应2个基础变量的结构可靠度基本理论。结构抗力的不确定性可以由统计学上的平均值和变异系数（cov或）Ω来描述。变异系数指变量的标准差和平均值的比值。敏感度分析的结果显示结构抗力的变异系数（ΩR）在其应用范围之内时,在分析结构可靠度方面扮演着相当重要的角色。基于这些阐述,在预先指定的风险水平（pf）上ΩR一定有其上限。当结构抗力呈正态分布的时候,这个极限ΩR独立于荷载效应随机性,和安全指数β成反比。安全指数可以定义为在标准正态分布区间极限状态到原点之间的最小距离。在这个极限ΩR之下,结构可以在预定风险水平之下安全工作。中心安全系数（FS）可以由结构抗力和荷载效应的变异系数根据平方关系求得。然而,一些情况下结构抗力为非正态分布的情况并不少见。因此,等效正态分布的概念可以用来得到非正态分布结构抗力的ΩR极限。地质方面的随机变量可能是正态分布,也可能是非正态分布,结构抗力中基本变量之间的关系可能是线性也可能是非线性,或者非常复杂以致于结构抗力只能通过有限元分析才能得到。在此情况下,随机数可以通过蒙特卡洛模拟技术获得。拟合的结构抗力的分布可以在随机试验的基础上通过配合度检验确定。现实中,土壤的力学特性不是各向同性的,同样也不能认为是单一材料的,它们的不确定性是不可以被忽略的。简便的设计方式认为不确定参数是常数,并且通过使用定值的安全系数来确定结构截面,设计原则没有将土壤参数对安全系数的影响考虑进去。参考计算出来的失效概率表明,确定值的安全系数法无法保证足够的安全。因此,在某种情况下,安全系数大于等于3,对于结构容许承受能力,并不能认为太保守。     

Temps de transport au regard des changements démographiques en Île-de-France. Tendances passées et projections à l’horizon 2030

This paper investigates the evolution of travel time through travel time budget in the most densely populated region of Paris and its neighbouring regions, where the GDP per capita is the highest in France. Four consecutive household travel surveys available from 1976 up to 2001 allow us to compare travel time and travel time budget over the years and also to forecast Parisian mobility up to 2030. We have chosen to focus on the distinction between mandatory and non-mandatory trips, mandatory trips being defined as trips whose destinations are related to work, university or school. We have studied travel time related to demographic, socio-economic and geographical patterns in order to identify some key elements determining travel time and urban mobility.     

Heat exchanger/catalytic system for reducing the exhaust emissions from diesel engines

A system has been researched over the past 3 years for reducing the exhaust pollutants from diesel engines for light commercial vehicles. The system researched achieves Euro 6 standards for reduction of polluting gases (CO, HC, PM, NO). It consists of 4 main sections: 1. A heater and heat exchanger (HE); 2. A CO/HC oxidising catalyst (D°C); 3. Pt catalyst on a diesel particulate filter (DPF); 4. A NO reducing reaction (SCR) within the DPF. The system operates as follows. The exhaust gas contains oxidising gases, namely both O₂ and NO₂. The levels of CO and HC are oxidised by O₂ to CO₂ for temperatures above 200°C. Carbon (PM) is oxidised to CO₂ by NO₂ but requires a temperature above 250°C. The operating exhaust temperature of 300°C is ideal for the removal of NO by using the Pt catalyst and the CO generated within the DPF. The heater is required to be able to raise the exhaust temperature at any time to 300°C in order to optimise the performance of the system, since diesel engine exhaust temperatures vary between 160°C (slow speeds) to 350°C (high speeds). Considerable heat is required (??3 kW) to maintain the exhaust gas for a 2l engine at 300°C for engine idle conditions. Therefore a heat exchanger is required to re-circulate the input heat and thereby reduce the maximum power consumption to a maximum of 500W over the engine full operating test cycle. This energy is supplied by the engine battery and alternator. Experimental results have been obtained for the exhaust from a Kubota diesel engine and the reductions in exhaust emissions of 83% (CO/ HC), 58% (NOx) and 99% (PM) were obtained. The PM was continuously cleaned so that there was no build up of back pressure.     

Maglev Vehicle/Guideway Vertical Random Response and Ride Quality

Summary The research and development (R & D) of maglev technology had made a great progress in China since the early 1980s. Especially, a 35 km-long Shanghai high-speed maglev railway employing the German Transrapid system began to be constructed on March 1, 2001. Based on the Transrapid system, the paper develops a 10-degree-of-freedom model of maglev vehicle running over three types of guideways with constant speed. Random guideway irregularities are discussed and taken into account for simulation of the vehicle response and for evaluation of the ride comfort. Using the direct time integration method and the discrete fast Fourier transform (DFFT), random responses of the maglev vehicle-guideway systems are obtained and analyzed. Numerical results show that the resonant frequency of car body acceleration response is 0.5-1 Hz, and there is a 2.2 Hz periodic vibration due to the periodic configuration of rigid piers when the maglev vehicle travels over the elevated-beam guideway. The car body acceleration power spectral density (PSD) curves meet well the ride quality criterion of the urban tracked aircushion vehicle (UTACV) and the maximum acceleration of car body is less than 0.05 g. Moreover, the Sperling ride index values are less than 2.5 as long as the operational speed is less than 450 km/h. It is concluded that the maglev vehicle ride quality is quite well.     

锰粉加工工人心血管功能的调查研究

对 ５５ 名锰粉加工工人和 ５６ 名对照工人的调查结果显示，工人工作地点 Ｍｎ Ｏ２ 浓度几何均值为 １９６ ｍ ｇ／ｍ ３ （锰尘 ０１７～２２．２４ ｍ ｇ／ｍ ３ ），样品超标率 ８８７％ 。接触组头晕头痛、睡眠障碍、容易疲劳和记忆不良的主诉率明显高于对照组（ Ｐ＜００５～００１）。接触组和对照组的心电图异常、高血压和低舒张压检出率未见显著性差异，其心率、 Ｐ Ｒ间期、 Ｑ Ｒ Ｓ波、收缩压和舒张压的均值比较也没有显著性差异。接触组心电图异常和低舒张压的 Ｏ Ｒ分别是 １．５６（９５％ 可信区间为 ０７０～３．５０）和 ２．０８（９５％ 可信区间为 ０１８～２３．５７）。