动力定位深海采矿船作业过程数值分析

深海采矿是一种高科技且高难度的深水、超深水采矿技术,以往的研究成果中对采矿船动力定位过程与立管及设备耦合分析尚不充分.该文采用势流理论分析采矿船水动力性能,采用集中质量法与Morison方程对立管与中继舱进行动力学建模.船舶动力定位系统采用PID控制器结合Kalman滤波进行建模,同时模拟了推力分配单元,充分计及动力定位对耦合运动系统的影响,完成采矿船动力定位过程中的深海采矿系统时域耦合数值分析;计算获得指定海况下的采矿船、中继舱的运动状态,立管的张力以及推进器推力等信息;分析了动态模拟中动力定位的影响.仿真过程对于深海采矿设计分析具有参考价值.     

Public sector comparators for UK PFI roads: inside the black box

A public sector comparator (PSC) represents the hypothetical, risk-adjusted cost of a project—such as a road scheme—when that project is financed, owned and implemented by government. A PSC is commonly used in public procurement decision-making as a yardstick against which private investment proposals are evaluated. Using original material released by the UK Highways Agency for the first time, the author recreated the PSCs used for the evaluation of the first eight road projects to be promoted under the UK’s private finance initiative (PFI). Alternative assumptions regarding project risks were modelled using different levels of optimism-bias uplift, and the impact on value-for-money of using different discount rates was evaluated. Public sector comparators have attracted considerable attention in the literature as they retain a pivotal role in the policy decision to use—or not use—private finance. However the fact that their detail is usually kept confidential by public sector procuring agencies—because of commercial sensitivities—has restricted informed discussion and open debate. Now the architecture of these comparators is laid bare for critical examination. It has generally been assumed that any reduction in the discount rate used in PSC calculations will favour conventional procurement over PFI-type contracting arrangements. The research reported in this paper demonstrates that the relationship between the discount rate and the attractiveness of using private finance is not as simple as has been assumed, and the outcome in terms of value-for-money is not as predictable as has previously been reported.     

船用动力装置智能协调控制策略研究

介绍了智能协调控制的原理及其在某船核动力装置控制系统中的应用，对装置的仿真结果表明，船用核动力系统在大幅度变负荷的动态过程中，该智能协调控制器能够有效地降低一回路系统的压力波动幅度和一回路冷却剂平均温度的波动幅度，明显地改善了系统的动态品质。     

Error and optimism bias in toll road traffic forecasts

Traffic forecasts are employed in the toll road sector, inter alia, by private sector investors to gauge the bankability of candidate investment projects. Although much is written in the literature about the theory and practice of traffic forecasting, surprisingly little attention has been paid to the predictive accuracy of traffic forecasting models. This paper addresses that shortcoming by reporting the results from the largest study of toll road forecasting performance ever conducted. The author had access to commercial-in-confidence documentation released to project financiers and, over a 4-year period, compiled a database of predicted and actual traffic usage for over 100 international, privately financed toll road projects. The findings suggest that toll road traffic forecasts are characterised by large errors and considerable optimism bias. As a result, financial engineers need to ensure that transaction structuring remains flexible and retains liquidity such that material departures from traffic expectations can be accommodated.

船舶动力定位系统滤波器的设计与研究

建立了船低频数学模型，对高频实验数据采用周期图法进行了功率估计，并根据功率谰估曲线建立了船高频数学模型，据此设计的有限冲激滤波器和最优估计滤波器已应用在某船动力定位系统中，效果良好。     

方形土楼屋盖风荷载的数值模拟分析

为探讨屋面坡角和高径比对客家圆形土楼屋盖风荷载的影响,应用数值模拟方法,在不同方向角下分别对不同的坡角和高宽比情况下土楼的屋盖极值风压系数和净风压系数进行参数分析,采用SSTk-ω湍流模型,建立具有代表性的单体方楼德辉楼的数值风洞模型,得到了屋盖极值风压系数和净风压系数随坡角、高宽比变化的分布曲线.综合考虑2种风压系数和风流场的影响,结果表明：方形土楼抗风效果较好的坡角为45°,而高径比是0.45.