Improved customs inspection at a small international airport: Case study: Colombo

The present procedures for processing arriving passengers at the Colombo International Airport cause inordinte waiting times. An alternate plan, which is based on state of the art customs procedures, and which can reduce waiting times significantly while maintaining a high level of enforcement, is proposed. The present and proposed procedures are analyzed and compared with respect to passenger waiting times, using deterministic queueing theory. An optimal inspection rate of passengers by the customs service is proposed taking into account the fraction of inspected passengers, the waiting time of passengers and the cost of customs processing.     

摆式车辆数值模型与试验台及线路试验结果的比较

介绍了一个运用于摆式车辆的动力学性能仿真的数值计算模型,特别考虑了曲线通过工况。在此模型中,把实车上使用的控制软件和车辆数值计算机械结构模型结合起来,再现了倾摆主动控制装置的动力学。为了验证数值计算仿真模型,把数值计算结果与试验台试验及室外线路试验结果进行了比较。     

Geographical variation in traffic-related mortality and morbidity among pedestrians in Quebec, 1983-1988

In this study we analyze the dmographic and geographical distribution of pedestrian accidents (n=28,452) in the Quebec Municipalités régionales de comté (MRC) reported between January 1, 1983 and December 31, 1988. In order to be able to make comparisons between MRCs, we have created in Comparative Mortality Index and a Comparative Morbidity Index. We use a logistic regression model to single out explanatory factors. The main tendencies which are apparent in the demographic analysis are an overrepresentation of young persons and elderly persons in the accident statistics, and that men are more at risk than women. Men 15 years and under and men 65 years and over are more at risk of being involved in a fatal pedestrian accident. The geographic analysis show that among men, the average mortality rate is one and a half times greater in rural MRCs than in urban MRCs; among women, rural mortality is two and a half times greater than urban mortality. In the case of non-severe injuries we note an over-representation of urban MRCs. Young persons 15 years or less who live in an urban, populated zone are those most at risk of being involved in a pedestrian accident. Identifying high risk groups or areas is a prerequisite step for injury prevention and control.     

≤T^nph极小集与Homer—Spies猜测

本文定义了在多项式时间界下不确定图灵纯正多项式归约(记为≤_T~(n p h))的概念,讨论了≤_T~(n p h)极小集的性质、≤_T~(n p h)极小集与≤_T~(p h)极小集的关系。据此,对Homer-Spies猜测提供了一个解答:P=NP当且仅当存在一个集合A,既是≤_T~(p h)极小集,又是≤_T~(n p h)极小集,且deg_T~(p h)(A)=deg_T~(n p h)(A)。     

Simulation Approach to the Effect of the Ratio Changing Speed of a Metal V-Belt CVT on the Vehicle Response

In regard to the belt and pulley system of a metal V-belt CVT, the characteristics of the ratio changing speed is obtained by experiments. It is summarized in a practical and simple experimental equation. By using this equation a simulation model is developed to analyze the response of a vehicle with a metal V-belt CVT to a rapid pulley ratio change. The simulation results are in reasonable agreements with experimental results.     

货运电力机车

概述货运电力机车的技术要求和欧洲货运电力机车的技术现状,重点介绍意大利货运机车的特点.     

A capacity restraint transit assignment with elastic line frequency

This paper proposes a new formulation for the capacity restraint transit assignment problem with elastic line frequency, in which the line frequency is related to the passenger flows on transit lines. A stochastic user equilibrium transit assignment model with congestion and elastic line frequency is proposed and the equivalent mathematical programming problem is also formulated. Since the passenger waiting time and the line capacity are dependent on the line frequency, a fixed point problem with respect to the line frequency is devised accordingly. The existence of the fixed point problem has been proved. A solution algorithm for the proposed model is presented. Finally, a numerical example is used to illustrate the application of the proposed model and solution algorithm.     

Flexible Bodies in Multibody System Codes

Multibody codes are'efficient tools to simulate nonlinear dynamic behaviour of rigid and flexible multibody systems undergoing large overall motions overlaid by small elastic deformation. This paper gives an overview of common approaches for the equations of motion of flexible body models and presents a general way to prepare the required data including geometric stiffening terms. In particularly, for the nodal approach the data are derived using standard results of a finite element analysis of the body. The computation of coefficient matrices describing the equations of motion is done outside the finite element code by matrix manipulations only. The data are stored in a standardised object-oriented structure. Consequently, the data set is independent of the formulation of the multibody system code.     

与速度有关的高负荷轮轨接触的粘着力(一)

为确定与速度有关的轮轨间的粘着力,设计了一种包含了与温度、弹性模数以及屈服点有关的动力学模型.