Organisation form,scale effects and efficiency in the British bus industry

The British bus industry is examined in light of fundamental reform in ownership and regulation. The industry is divided between privately and publicly owned companies, with the private sector further split between publicly listed owned subsidiaries and private limited companies. The change in ownership structure since privatization is analysed, and Data Envelopment Analysis used to estimate the extent of returns to scale and technical efficiency, as defined by one output and three inputs. Technical efficiency is further divided into managerial and organisational components, and comparisons made of median efficiency levels using a Mann Whitney statistical test.Increasing returns to scale are found for smaller companies, but the size of such returns varies with the company type. A minimum efficiency scale is identified, with constant returns above this point. A high degree of technical inefficiency is found to be present in the industry, which may initially suggest a lack of competition and reflect the oligopolistic structure that has emerged since privatisation. Privately owned companies are identified as more technically efficient, however this is due to significantly less organisational constraints, and considerable managerial inefficiency exists in this group. It is finally concluded that the high level of inefficiency may not reflect ownership, but rather industry characteristics, and rather than a lack of competition may be indicative of wasteful competition. It is suggested therefore there may be a need to make the market contestable rather than openly competitive.     

利用Web缓存解决网络流量问题

随着访问量的不断提高，单纯地采用高级硬件来处理整个加载置，并不是很好的解决方法，高速缓存即是一种有效的解决方案。高速缓存通过将频繁用于访问的数据和网页存储在服务器或客户机的内存中，减轻了Web服务器的负载，有效的解决了网络拥塞问题。详细探讨了Web高速缓存的多种存储方式和工作原理，阐述了在ASP．Net应用程序中的缓存机制。     

浅谈基于CAN现场总线的数据采集系统

本文以微机监测为例介绍了基于CAN总线的数据采集方案。     

移动式信号设备故障记录分析装置

采用便携采集模块及综合采集设备进行现场采集,并配合数据分析软件,对于铁路现场偶发信号故障及曲线波动异常等不明故障进行监测及分析,可有效提高信号设备故障定位的准确性、方便性及时效性。     

混合动力城市客车燃料电池系统总体设计

讨论了某型城市客车燃料电池系统设计中的关键问题,包括燃料电池、超级电容、电机等关键零部件的参数匹配.通过合理匹配和布置,从而提高了行车可靠性和安全性.     

基于CAN总线的水下机器人分布式控制系统

提出并实现了一种基于CAN总线的水下机器人分布式控制系统。与传统的集中式控制系统相比,分布式控制系统可以很容易地接入功能模块而无须对现有硬件进行重新设计,具有更好的可扩展性;并且各个节点间采用数字信号通讯,具有很强的抗干扰能力。开发了基于工业控制计算机的半实物仿真系统,模拟执行机构节点和传感器的工作,接入已完成的自动驾驶仪节点和数据记录及故障检测节点,对控制系统进行实时仿真测试,测试结果验证了该分布式控制系统设计的可行性。     

基于对象关系映射的油料装备信息系统

简要介绍基于对象关系映射的油料装备信息系统的研究必要性。综合信息资源系统基于B/S结构,使用.Net作为开发平台,C#语言。阐述对象关系映射和Nhiberate的概念和原理,并使用Nhiberate,在.Net下实现了对象关系映射。     

并联混合动力客车用交流传动系统的设计

介绍了电动汽车发展的基本情况，以并联双轴结构的油电混合动力客车为例，从主电路、电机和控制系统方面详细阐述了采用永磁同步电机的交流传动系统，描述了系统在可靠性方面所采取的措施。系统试验以及相关的试验结果表明，该传动系统性能优良。     

8米纯电动客车行驶共振分析及改进方案

从二自由度振动微分方程建立、悬架静态偏频计算、动刚度对悬架垂向振动影响分析三个方面入手,对车辆垂向振动进行了分析,找出了其共振原因,提出了具体改进方案。