Book reviews

Coastal Resources Management: Beyond Market and Bureaucracy by Robert B. Ditton, John L. Seymour, and Gerald C. Swanson. Published by D. C. Heath and Company, Lexington, Massachusetts, 1977, 191 pp., 6 figures.

The Urban Sea: Long Island Sound by Lee E. Koppelman, Peter K. Weyl, M. Grant Gross, and DeWitt S. Davies. Published by Praeger Publishers, 1976. 209 pp., 81 figures, 42 tables.     

A Practical Model for Deformation Prediction of Highway Subgrade Soils

This paper reports a practical constitutive relation for highway subgrade soils. The proposed model is derived based on the laboratory repeated-load testing of four subgrade soils. Statistical parameters generally used in the power model of subgrade permanent strain are expanded into material constants with engineering significance. The constitutional relation reported in this paper can be used in the mechanistic-based pavement design of highway flexible pavements and railroad tracks.     

基于虚拟边界条件一维搜索预报的并行算法

对网格方程组作多重网格区域分裂并行计算,虚拟边界预报提出一维搜索算法,并讨论相应的收敛性,通过ＧＳ迭代的性质,构造区间压缩算法,证明了其收敛性,指出此算法能有效地解决区域分裂并行计算中的远程信息传递和频繁通讯问题。     

PC局域网上分布式并行处理的性能评估

对ＰＣ局域网上ＰＶＭ分布式编程环境中网络并行计算的性能进行了详尽分析与评估,指出：在ＰＶＭ编程环境中网络并行计算与ＭＰＰ并行计算的根本 区别在于它们的通信行为不同。网络并行计算中的通信是顺序的,不仅通信和计算是顺序发生的,而且各次通信也是顺序发生的。而在ＭＰＰ并行计算中通信是由专门的通信部件并发完成。文章给出一个统一的公式来描绘这两类主要的并行处理系统的性状,并由此导出,对于网络并行计算其加速比服     

An introduction to airport APM systems

The purpose of this paper is to provide an introduction to the nature and purpose of airport automated people mover (APM) systems. Our objective is to provide a convenient research tool for persons seeking an introduction to the airport APM industry. Included are illustrations of typical system designs; a listing of existing airport APM systems, including a tabular presentation of selected data; an organization and discussion of the history and evolution of the existing systems; and a status report on current developments in the APM industry.     

Taxonometric evaluation

Transportation planning has for too long been unbalanced in that an excessive amount of time has been spent on building increasingly complex quantitative models at the expense of rather important aspects of the design and forecasting stages of the process. This paper therefore sets out to consider two related problems: that of forming a coherent and useful link between the design and evaluation stages and that of suggesting a method of dealing with probabilistic forecasts within the evaluation model.The solutions to both of these problems are linked. It is suggested that the structure of and variables contained within the formal evaluation model must also necessarily play a part in the scheme design or selection process. This process is itself seen as one of hierarchical selection wherein classes of scheme or solution are successively more explicitly identified as sensibly different and, where possible, the preferred class is identified. Central to this taxonometric procedure is the idea of sensible differentiation between classes whose characteristic performance is only known uncertainly and some algorithms for achieving this are suggested.     

Developing Metro Systems in the People’s Republic of China: Policy and Gaps

Rapid urbanization has taken place in China since the Open Policy in 1978. In face of the growing demand for mobility in large cities, new metro systems were developed in large cities like Guangzhou and Shanghai. At present, there are seven cities with 10 metro lines under construction. What are the policy issues and major challenges of developing metro systems in China? This paper systematically reviews the current situation and highlights three major gaps that Chinese cities have to overcome in planning metro systems. They are the technology gap, the financing gap and the affordability gap. A discussion of these gaps in the Chinese context leads us to the conclusion that early planning and careful studies are important in the development of metro systems in China. Moreover, the existing official criteria (population and economic power) for approving the building of metro systems are insufficient and should be supplemented by more vigorous evaluation criteria.