Risk and return of U.S. water transportation stocks over time and over bull and bear market conditions

The aim of this paper is to investigate the behaviour of water transportation company stock returns in the U.S. stock exchanges from 1985 to 1994 in order to determine whether the systematic risk of this industry is different from that of the 'average' company in the market, whether it has changed over the ten year period, over bull and bear market conditions, and whether there is a firm 'size' effect in the industry. In the context of the Capital Asset Pricing Model (Capm), we find that the systematic risk of the shipping industry return is not different from that of the 'average' company. It is also found that the covariance of water transportation companies with respect to the overall stock market return did not change over the ten year period although it appears that it has changed over normal upward/downward market movements. There is also reasonable evidence that the intercept of the equation might have changed over normal upward/downward market movements. Finally, we document contradictory evidence regarding the size effect; during the period 1985-1989 we find small companies to have significantly higher returns and risk while during the period 1990-1994 medium size companies tend to have higher risk than small and large firms, which is not however compensated by higher returns.     

基于偏差分析的交通事件自动检测算法

高速公路事件检测是交通管理与控制中十分重要的环节。将交通流动态预测与事件检测相结合,探讨了基于偏差分析的事件识别方法。该方法对3个主要的交通流参数,交通量、地点车速和时间占有率进行动态预测,对预测值与实际值的偏差进行统计分析,明确了事件检测的具体步骤和事件发生概率的计算模型。该方法不受检测路段具体位置和时间的限制,具有较高的检测率和较小的误报率,有助于管理人员制定决策。     

Driver steering and muscle activity during a lane-change manoeuvre

The article reports an experimental study of driver steering control behaviour in a lane-change manoeuvre. Eight test subjects were instrumented with electromyography to measure muscle activation and co-contraction. Each subject completed 30 lane-change manoeuvres with one vehicle on a fixed-base driving simulator. For each driver, the steering torque feedback characteristic was changed after every ten manoeuvres; the response of the vehicle to steering angle inputs was not changed. Drivers' control strategies were found to be robust to changes in steering torque feedback. Path-following errors, muscle activity and muscle co-contraction all reduce with the number of lane-changes performed by the driver, suggesting the existence of a learning process. Comparing the test subjects, there was some evidence that high levels of co-contraction were used to allow high-frequency steering inputs to be generated. The results contribute to the understanding of vehicle-driver (and more generally, human-machine) dynamic interaction.     

基于组合模型的港口集装箱吞吐量预测方法

以某港1990~2003年集装箱吞吐量为实测数据,建立其集装箱吞吐量的和灰色系统等预测模型。对比该港2004~2006年集装箱吞吐量各模型预测值与实际值的差异,分析了差异产生的原因及其单一预测模型的局限性,提出了基于组合预测的港口集装箱吞吐量预测法。对港港口集装箱吞吐量发展趋势进行预测,作为未来对港口岸线资源有效的开发利用,基础设施的合理规划、建设以及港口功能拓展的依据是很有必要的。     

Evasive manoeuvres with a steering robot

In the pursuit of an objective rating on vehicle stability performance, it is always desirable to reduce disturbances and inconsistencies during experimental evaluations, especially the ones introduced by human drivers. This paper presents the development of a steering robot designed for closed-loop steering tasks during evasive manoeuvres. It describes the controller structure and discusses experimental results, in addition to simulation/vehicle model verifications and theoretical control analysis.     

外加电流阴极保护技术在天津港滚装码头预制梁中的应用

外加电流阴极防护是钢筋混凝土结构防腐蚀的主要技术手段之一。文章结合外加电流阴极保护技术在天津港滚装码头预制梁工程中的实际应用,介绍了外加电流阴极保护的原理和保护效果,是国内工程中的首次应用,将为我国今后外加电流阴极防护技术的发展和进步提供重要的参考和借鉴。     

微机控制技术在内燃机车上的应用及开发方向

分析对比了内燃机车微机控制系统的组成及控制功能,阐明了各个微机控制系统的优缺点,介绍了在现有内燃机车微机控制系统的基础上,实现模块化、简统化的方案.     

FRP正弦波形夹心桥面板的等效有限元模型

以FRP正弦波形夹心桥面板作为研究对象,得到等效正交各项异性实心板,通过理论分析和数值对比,证明了方法的可行性;采用该法对一实际的FRP正弦波形夹心板桥进行了模态分析。     

基于多媒体时钟的定时控制

由于Windows平台图形界面的易操作，使得在各行各业得到迅速的普及。这在工业控制领域也不例外，但是由于Windows操作系统在大部分情况下是以队列形式工作的，使得在Windows下实现实时控制成为了难题。利用多媒体时钟可以很好地实现Windows实时控制。     

山区铁路检养修分开线路维修模式的探索

针对成都铁路局线路维修管理存在的主要问题,探讨了符合山区铁路特点的检养修分开线路维修模式,对生产力布局、维修组织、作业方式、设备检查监控、天窗修作业项目、基地建设和机械配备标准等生产管理办法提出建议。