Representing mental maps and cognitive learning in micro-simulation models of activity-travel choice dynamics

This paper develops a model, based on Bayesian beliefs networks, for representing mental maps and cognitive learning into micro-simulation models of activity-travel behavior. Mental maps can be used to address the problem that choice sets in models of travel demand are often ad hoc specified. The theory underlying the model is discussed, a specification is derived and numerical simulation is used to illustrate the properties of the model.     

预应力CFRP板加固钢板轴心受拉行为分析

首先分析比较预应力的施加方法和锚固方式,然后基于一维线弹性理论,对预应力碳纤维增强复合材料(CFRP)板加固钢板体系的受力过程进行分阶段分析,得到在张拉预应力和受载工况下CFRP板、钢板、胶层的应力分布解析式及CFRP有效粘结长度公式、弹性压缩带来的预应力损失值;最后利用ANSYS中Solid95三维单元进行有限元模拟对比分析。结果表明:直接张拉CFRP板能有效控制预应力及其加固效果,比间接法施加预应力有更多优势;采用高强螺栓连接的平板夹具锚传递大部分荷载,改善了非预应力粘贴加固界面的薄弱特点;该理论分析及有限元模型是可靠、有效的。     

Financing public transport systems in Kuala Lumpur,Malaysia: challenges and prospects

Most major cities across the world today are facing an intractable challenge of financing public transport. In Kuala Lumpur for example, public transport services are somewhat poor in part because of the failure of major operators to secure ample funding. Previous funding programs implemented in the city have failed to produce a replicable model for financing public transport. Due to numerous financial problems and the dismal performance of privately owned transport firms, the State has in the recent past emerged as a key source of funding for the public transport sector in Kuala Lumpur. This article argues that, despite the insuperable challenges, prospects for the future funding of public transport in Kuala Lumpur appears to be good. The article also draws lessons from both Tokyo and Hong Kong. In order to address the funding deficit facing the public transport industry in the city it is crucial that more viable strategies and policies such as value capture and public–private sector partnerships are adopted by the urban authorities.

A statistical approach to the traveling salesman problem

A statistical approach is shown to be adaptable to the N-city traveling salesman problem by considering route distances to be random variables which are continuous and normally distributed. A solution to the shortest route distance and path can be approximated by utilizing a Monte Carlo simulation to obtain a representative sample of possible journeys. The approach involves recursive statistical inference which is used to select next-city visits leading to the most probable minimum route path. A statistical selection of the minimum route path is computationally efficient and computer run time increases in proportion to the square of the number of cities as opposed to an (N - 1)! increase for a deterministic approach. The accuracy of the statistical approach is directly proportional to the number of Monte Carlo simulations.     

The influence of transportation improvements on interregional trade in Brazil

In this study the impact of transportation improvements on Brazilian interregional commodity flows are considered. The decreasing friction of distance is measured by two variants of the gravity model. First, distance coefficients are calculated for trade among all states in 1942 and 1962. Second, distance coefficients for each state's imports are calculated separately and then related to state per capita income, for the year, 1962. Both the time-series and cross-section results indicate a significant diminution in the friction of distance in the course of Brazilian development. The degree to which trade has integrated the national economy is assessed by the convergence of agricultural prices. Not only have interregional price differentials tended to diminish, but regional price structures are becoming more similar. The interrelation of these price structures provides a method of regionalizing the Brazilian space-economy.Most of the data for this study were collected during the author's tenure as Ford Foundation Visiting Professor at Instituto de Pesquisas Economicas, Universidade de Sao Paulo, Brazil. The Milton Fund and the Department of City and Regional Planning, both of Harvard, sustained the completion of this research. Milton Campanario and Abby Rashid provided invaliable assistance in assembling the data. Jeffrey Dutton of the Harvard Laboratory for Computer Graphics provided a program for calculating distances. William McAuliffe suggested some imaginative interpretations of the factor analysis.     

The analysis of entropy models with equality and inequality constraints

Entropy models are emerging as valuable tools in the study of various social problems of spatial interaction. With the development of the modelling has come diversity. Increased flexibility in the model can be obtained by allowing certain constraints to be relaxed from equality to inequality. To provide a better understanding of these entropy models they are analysed by geometric programming. Dual mathematical programs and algorithms are obtained.     

Physical characteristics of paratransit in developing countries of Asia

Paratransit modes play a significant role in the urban transport sectors of developing countries since in many cities more than half of the total public transport demand are carried by them. Rapid increase in urban population, per capita income, along with inadequate existing transport infrastructures have stimulated their usage as cheap and convenient public transport modes. This paper examines their present role and physical characteristics in a comparative form to provide a basic data for discussion of urban transport issues in developing cities.