The advantages of a high density,mixed land use,linear urban development

This paper describes the land use and transport characteristics of a strip of urban development located along the northern shore of Hong Kong Island. The strip of land, with an area of 22.5 sq. km, is 17 km long and has an average width of 1.3 km. It has a population of approximately one million and provides over 700,000 jobs. Despite its small size, it accommodates the CBD, residential districts, shopping complexes as well as most of the civic/institutional facilities that a city needs. Its urban form is linear not by design but by default – the topography of the area has constrained the development from spreading sideways. Surprisingly however, apart from economy in land utilization, it is considered to possess three other good qualities: high accessibility enjoyed by residents; few roads and commercially viable public transport. Its travel characteristics are analyzed, using results of a home interview survey conducted by the Government in 1992. In addition, various statistics published by the Government and public transport authorities are also used in the analysis.     

A systemic overview of non‐motorized transportation for developing countries: An agenda for action

All through the twentieth century transportation planning and the implementation of transportation facilities in the developing world was heavily weighted toward motorized transportation (MT), despite the fact that non‐motorized transportation (NMT) constitutes a significant proportion of all trips. However, in the last two decades many researchers and practitioners all across the world have recognized the importance and advantages of NMT, and their investigations and findings have contributed toward identifying, if not mitigating, some of the more glaring problems in these countries. Unfortunately, most of these investigations have been performed in a piece‐meal and disjointed fashion. This paper explores the complex and sometimes poorly understood set of relationships between transportation and its links to a myriad of other factors, such as landuse, sustainability, safety, energy, ethical issues, value of time, telecommunication, environmental justice, and equity. The main objective of this paper is to provide a systemic overview of NMT by describing its multi‐dimensional aspects and to assist developing countries in formulating an “Agenda for Action”.     

Development of simplified analytical methods for predicting the response of offshore structures to blast and fire loading

This paper discusses structural response to blast loading and temperature changes in fires. Both extreme events can be modelled using a range of analytical techniques from simple methodologies to the very complicated finite element analysis. The relatively simple techniques are appropriate for this type of problem and degree of accuracy required given the level of uncertainty in the loading. Given specific boundary conditions and physical properties, the methodologies proposed in the paper provide as good estimates of the dynamic response to blast loading and temperature increases in fires as the more sophisticated finite element method. Experimental data compares well with the analytical results.     

A cross-section analysis of stock returns: The case of shipping firms

This paper undertakes an analysis of the determinants of the cross-section of expected stock returns of 19 shipping companies listed in the US, Norway, Stockholm and London. Various factors, including company stock market beta, divided yield, and financial leverage have been identified in the finance literature as determinants of share price performance. We capitalize on these findings and add one more industry specific factor, the average age of the company's fleet, to quantitatively analyse the determinants of the performance of shipping shock returns. We use the Fama-MacBeth methodology to empirically test whether the five factors above have a significant effect on shipping stocks' performance. Our results indicate that the industry specific factor (the average age of the fleet) plus financial leverage, are significant in explaining shipping stocks' returns, wheras the stock market beta and the dividend yield are far less significant.     

Cybertran: A systems analysis solution to the high cost and low passenger appeal of conventional rail transportation systems

A new transportation system is described. CyberTran is a steel wheel on rail system designed to travel on elevated guideways, utilizing large numbers of 6 to 20 passenger automated vehicles weighing less than 10,000 pounds. The benefits from these light weight vehicles include dramatically reduced system cost and increased passenger appeal. The system described has been prototyped and tested at the Idaho National Engineering and Environmental Laboratory, a U. S. Department of Energy Research and Development Laboratory.     

Meroplankton abundance in the Northeast Water Polynya: Insights from oceanographic parameters and benthic abundance patterns

We investigated meroplankton (planktonic larvae of benthic organisms) abundance and distribution in the Northeast Water (NEW) Polynya, located on the northeast coast of Greenland, from July 15 to August 15, 1992. Meroplankton was present at all sites visited (0.03–84.83 individuals per m³); at one station meroplankton comprised 8.28% of total zooplankton. Total meroplankton abundance was correlated with total zooplankton abundance and total benthic infaunal abundance but was not correlated with either microscopic carbon concentration or primary productivity. Examination of distribution data for barnacle nauplii and adults indicated that both adults and larvae were concentrated at the same locations. Patterns of distribution were also examined for stelleroid plutei, polychaete larvae and trochophores. There were distinct geographic patterns in total and class-specific meroplankton distributions, with maximal abundances occurring over the Belgica Bank and in the eastern regions of the Westwind Trough and minimal abundances in the Belgica Trough. The apparent control of meroplankton distribution by the hydrography of the region, coupled with the correlation between meroplankton, zooplankton and adult infaunal abundance, reinforces the hypothesis that hydrography plays a major role in controlling the distribution of biota in the NEW polynya (Ambrose and Renaud, 1995; Ashjian et al., 1995, 1997-this volume; Smith et al., 1995; Piepenburg et al., 1997-this volume).     

Dynamic tyre friction models for combined longitudinal and lateral vehicle motion

An extension to the LuGre dynamic friction model from longitudinal to longitudinal/lateral motion is developed in this paper. Application of this model to a tyre yields a pair of partial differential equations that model the tyre-road contact forces and aligning moment. A comparison of the steady-state behaviour of the dynamic model with existing static tyre friction models is presented. This comparison allows one to determine realistic values of the parameters for the new dynamic model. Via the introduction of a set of mean states we reduce the partial differential equations to a lumped model governed by a set of three ordinary differential equations. Such a lumped form describes the aggregate effect of the friction forces and moments and it can be useful for control design and online estimation. A method to incorporate wheel rim rotation is also proposed. The proposed model is evaluated by comparing both its steady-state as well as its dynamic characteristics via numerical simulations. The results of the simulations corroborate steady-state and dynamic/transient tyre characteristics found in the literature.     

PWM逆变器供电异步电机传动的去耦直接控制

提出一种用于脉宽调制(PWM)逆变器供电异步电机的转矩和定子磁通直接控制方法.这种被称为去耦直接控制(DDC)的基础是一个去耦矩阵,它允许对定子磁通和转矩单独控制.将该方法和著名的直接磁场定向控制(FOC)和定子磁通矢量控制(SFVC)进行比较.提出了2种基于DDC的方案.第一种是确定定子电压矢量,以便转矩和磁通跟踪其各自在一个采样周期内的基准轨迹.第二种是利用PI控制器分别控制转矩和定子磁通误差的动态特性.与FOC和SFVC相似,这些方法均考虑到了整个电机动态特性范围内不需要坐标变换,并可大幅度地降低计算工作量.这2处控制方案已经完成试验,并且与FOC和SFVC进行了比较.试验结果表明,所提出的PI-DDC控制非常有效.     

Fleet deployment optimization for liner shipping Part 2. Implementation and results

We use linear programming (LP) for solving the problem of the optimal deployment of an existing fleet of multipurpose or fully containerized ships, among a given set of routes, including information for lay-up time, if any, and type and number of extra ships to charter, based on a detailed and realistic model for the calculation of the operating costs of all the ship types in every route and on a suitable LP formulation developed in earlier work of the authors. The optimization model is also applicable to the problem of finding the best fleet compostion and deployment, in a given set of trade routes, which may be the case when a shipping company is considering new or modified services, or a renewal of the existing fleet. In addition, two promising mixed linear-integer programming formulations are suggested.