混沌映射的保密性能分析

通过实例说明两个具有拓扑共轭关系的混沌映射具有相同的Lyapunov指数.指出了仅仅使用Lyapunov指数作为混沌映射的密码学特性描述,具有一定的局限性.并利用混沌序列的伪随机特性,通过计算映射的自相关函数、互相关函数等随机数值特性,结合Lyapunov指数,分析了混沌序列的保密性能.     

Emerging organizational values in shipping: Part 4. Decentralization—the redefinition of authority in shipping company organization

Decentralization is a major theme of organizational change in shipping. It is often seen as ‘putting power back aboard ship’. However, the authors argue that this view is too simple. Decentralization poses fundamental questions about the entire management structure of the shipping company. The redistribution of authority necessary for decentralization is discussed in terms of the company organization structure.     

Workshop 3A: Governance,contracting, ownership and competition issues in public transport: Looking up not down

Workshop 3A focussed on matters of institutional design that seem likely to improve public transport outcomes. It started by defining high level outcome goals, as measures of ultimate public transport success, and then identified the major societal issues that public transport systems can help to resolve. These issues were separately defined for Southern African and western settings. The importance of taking an integrated approach to transport, particularly land use/transport integration, was seen as fundamental to goal achievement. Workshop papers provided many and varied examples of this importance, ranging from PPPs for major public transport projects to system design issues and contracting out of services. The Workshop included detailed discussion on paratransit development in Southern Africa, where relationship management is proving to be critical, in-line with much previous Thredbo discussion about the important role of trusting partnerships. Parallels and contrasts were drawn with paratransit in western settings. Competition in passenger rail was also a focus, with some questioning of the benefits of franchising. Discussion concluded by proposing recommendations for policy and research and suggesting agenda items for future Thredbo Conferences.     

Applications of intuitionistic fuzzy set aggregation operators in transport multi-factor project evaluation

Abstract

An intuitionistic fuzzy set (IFS) is a generalisation of a fuzzy set characterised by a truth membership function and a false membership function. The former is a lower bound on the grade of membership of the evidence in favour of a particular element belonging to the set and the latter is a lower bound on the negation of that element belonging to the set derived from evidence against that element belonging to the set. A similar concept is a vague set, though vague sets have been shown to be identical to IFSs. In the context of project evaluation, an IFS may be used to represent the degree to which a project satisfies a criterion and the degree to which it does not. Aggregation of such IFSs has been considered in recent years to identify a best project in terms of several criteria or factors. A particular desirable way to aggregate IFS is in terms of an ordered weighted average (OWA) which can be expressed in different forms such as arithmetic and geometric. In an OWA operator, weights are applied to the position of an element in the aggregation. In addition, hybrid OWA operators may be developed to not only weight the position of elements in the aggregation but the element itself. An example is given relating to the Kuranda Range Road upgrade (Queensland, Australia) which is limited by grade, poor overtaking opportunities, poor horizontal alignment and other constraints and the road is expected to become increasingly congested over the next few years. A more flexible multi-factor decision method is used to identify a ‘best’ project from a set of four alternative projects.     

《液压传动》课程教学改革与实践

液压传动课程是机械类专业的一门重要技术基础课,几年来学校通过多媒体的充分运用、教学内容结构调整和内容创新,考试方式的改革和教师的自身素质的提高等方面进行了探索与实践,提高了教学质量,较好地实现了教学目的。     

罐车牵引梁失效容限分析全尺寸验证试验

介绍了用铁道车辆的全尺寸多轴液压伺服台－－模拟加载器，以及建立在裂纹分析方法基础上的失效容限分析，并以北美铁路摧车工业所承担的罐车牵引梁研究项目为例，采用模拟加载器来验证失效容限分析。