An approach to the evaluation of changes in travel unreliability: A “Safety margin” hypothesis

Even where unreliability has been recognised as a significant component in the generalised cost of trip-making, few attempts have been made to quantify it in the evaluation of transport improvements. This neglect is perhaps explained by the difficulty of observing a suitable trade-off situation in which transport users can trade money directly or indirectly for improved reliability of their transport modes.This article investigates the characteristics of a possible trade-off which might be made by commuters — the allowance of extra time for travelling in order to avoid unpredictable lateness at destination. The form of the costs of a response to unreliability of this nature is considered within a more general framework of the allocation of time under uncertainty or risk conditions.Certain other approaches to the evaluation of travel unreliability are reviewed and a brief outline is given to a current research project which attempts to test the applicability of the safety margin in London commuters' timing of the trips that they take to work.Any views expressed in this article are those of the author and are not necessarily those of the Department of the Environment.     

舰船基座设计研究

探讨了舰船基座的一般设计准则，介绍了一些典型舰船的基座设计，分析研究了舰船基座的计算设计方法和舰船基座的试验研究方法，提出了舰船基座设计的一般步骤。     

军用软件质量及其测试的探讨

随着计算机科学的发展，推动着信息化战争的不断发展。提高了对军事装备的性能要求，进而加强了对军用软件的质量要求。强调用软件测试技术提高军用软件质量。     

舰船结构可靠性的定性设计方法

提出一种舰船结构可靠性的定性设计方法，在分析故障及其影响的基础上，不断改进设计、消除故障并提出质量控制、使用限制及防救措施的方案，可以保证对舰船结构可靠性的定性要求。     

离散最大值原理在系统可靠性中的应用

给出一种受多个非线性约束条件限制的多级并行系统可靠性优化计算方法，这种方法适用于约束函数可分的情况，其特点是计算简单，容易实现计算机自动处理。     

A Method to Analyse the Dynamic Behavior of a Motorcycle Front Suspension Equipped with Sequential Dampers

This work analyses the dynamic behavior of a motorcycle front suspension equipped with passive sequential hydraulic dampers, in some operative situations. The dampers, with non-linear and asymmetric characteristics, may be regulated in six different ways. Using experimental elasticity and damping data as reference parameters, and a simplified two-degrees-of-freedom model, some dynamic simulations were carried out in order to define damping parameters for optimal comfort and safety.     

智能化卷缆装置——变频电缆卷筒

结合起重机械对电缆卷筒的性能要求,着重介绍变频电缆卷筒的工作原理和控制方法.针对目前国际上采用变频方法控制的电缆卷筒,提出了新颖的、高集成度的控制思路,研制出性能优越的新型变频电缆卷筒,在实际应用中取得了良好的效果.     

The rationality of conference pricing and output policies. Part 2

In Part 1^*of this article a background to the economics of conference operation was provided, and conference fleet planning and single voyage costs were discussed. This part of the paper will analyse the economic objectives of conferences and will consider the implications of ending the conference princing structure. Some recommendations are also offered.