Uncertainty analysis of value for money assessment for public-private partnership projects

In recent years, private sectors are encouraged to take an active part in franchising of urban infrastructure investments and operations, which promotes the rapid development of public-private partnership (PPP) in infrastructure and public service supply. Value for money (VFM) assessment has been officially proposed to provide a reference for selection of projects planning to adopt PPP. Based on the bottlenecks of VFM application in China and the uncertainties for urban infrastructure PPP projects, a discounted cash flow (DCF) model is established for VFM of infrastructure PPP projects. Then, a Monte Carlo simulation model is established on the basis of uncertainty factors for VFM. Through the analysis of Huai’an trams PPP project, coping strategies of uncertainties for VFM are put forward. Findings of the research may propel the establishment of a complete VFM evaluation system for PPP projects. Key instructional functions of VFM during the process of decision-making can be brought into full play and PPP may develop orderly.     

CT reconstruction with priori MRI images through multi-group datasets expansion

Computed tomography (CT) reconstruction with a well-registered priori magnetic resonance imaging (MRI) image can improve reconstruction results with low-dose CT, because well-registered CT and MRI images have similar structures. However, in clinical settings, the CT image of patients does not always match the priori MRI image because of breathing and movement of patients during CT scanning. To improve the image quality in this case, multi-group datasets expansion is proposed in this paper. In our method, multi-group CT-MRI datasets are formed by expanding CT-MRI datasets. These expanded datasets can also be used by most existing CT-MRI algorithms and improve the reconstructed image quality when the CT image of a patient is not registered with the priori MRI image. In the experiments, we evaluate the performance of the algorithm by using multi-group CT-MRI datasets in several unregistered situations. Experiments show that when the CT and priori MRI images are not registered, the reconstruction results of using multi-group dataset expansion are better than those obtained without using the expansion.     

基于多时间尺度的城市轨道交通短时OD估计

基于状态空间模型构建了城市轨道交通短时OD估计的多模型组合方法,估计早晚高峰期间15 min内进站客流的去向目的站.组合模型以不同时间尺度下的进站客流分流率为状态变量,并利用历史数据预估其中通勤客流的分流率,然后通过交互多模型算法加权融合不同时间尺度下的分流率估计结果.以北京地铁为案例,研究表明:早高峰期间的15 min分流率估计误差的平均值和最大值分别为16.4%和21.8%,晚高峰期间分别为22.7%和24.6%,比既有文献的估计误差减小了约一半.本文的研究成果可为实时的线网客流分布预测提供更准确的输入数据,以辅助运营管理部门实现客流预警和应急响应.     

The jurisdictional challenges to the prosecution of piracy cases in Kenya: mixed fortunes for a perfect model in the global war against piracy

Since 2008 Kenya has distinguished itself in the global war against piracy by undertaking prosecutions in the national courts of suspected pirates arrested in the high seas and handed over by navies of leading maritime nations under bilateral agreements (MOUs) entered into between Kenya and these leading maritime nations. As of July 2011, Kenya had over 20 convicted pirates serving jail terms ranging between 7 and 20 years and over 100 suspected pirates awaiting trial in national courts. This is the largest number of suspected pirates held and tried in any one state at any given time in modern history. To achieve this, Kenya had to effect far reaching changes in the law. In the initial stages, suspected pirates were charged under Kenya’s Penal Code (Cap 63 Laws of Kenya). However, the high court in the case of Re Mohamud Mohamed Dashi and eight others [2010] eKLR, ruled that Kenya had no jurisdiction to try suspected pirates under that law. In September 2009, Kenya passed a new law (the Merchant Shipping Act), which not only defined more comprehensively and extensively the offence of piracy, but also extended the jurisdiction of Kenyan courts to try piracy committed by non-nationals. Though the law gives Kenya a very broad jurisdiction to try suspected pirates, the process is still fraught with challenges due to lack of financial and human resources. In the case of Republic vs Hassan Jama Haleys Alias Hassan Jamal and five others [2010] eKLR, the court commented thus:

“… I must note that the ‘piracy trials’ have presented a unique challenge to the Kenyan legal system. We cannot ignore the fact that these are suspects who having been arrested by foreign naval forces on the High Seas are brought to Kenya for trial. They are strangers in the country, do not understand the legal system, may not know what their rights are and do not understand the language… the Kenyan Government and the International partners supporting these trials put in place a system to provide free legal representation for the suspects…”     

基于ADC模型的侦察雷达效能评估研究

文章针对侦察雷达的作战特点,分析了影响侦察雷达效能的因素,建立了侦察雷达系统效能评估指标体系,采用ADC方法对侦察雷达效能进行建模,并应用该方法对某型侦察雷达效能进行了分析,该方法可为以后侦察雷达系统的开发和研究提供参考和借鉴。     

乳酸-环氧大豆油共聚物的合成与表征

以乳酸为原料,采用熔融缩聚法合成了乳酸低聚物,然后将其与环氧大豆油(ESO)反应,采用红外光谱对产物进行表征.研究了ESO含量、反应温度以及反应时间对产物粘均分子量的影响.结果表明:环氧大豆油质量分数由2％增至8％,在150℃下与乳酸低聚物反应7h,当其质量分数为4％时得到的产物粘均分子量最高达16 599,与乳酸低聚物相比,分子质量得到了提高.再用接触角测定仪、拉伸实验对产物进行亲水性以及力学性能表征,与乳酸低聚物相比,乳酸-环氧大豆油共聚物的拉伸强度虽然有所下降但亲水性以及断裂伸长率却得到了提高.     

A new method for absolute datum transfer in seafloor control network measurement

To decrease the time consumption and the labor intensity in the absolute datum transfer of traditional seafloor control network measurement, a new method, namely sailing-circle positioning method, is put forward in this paper. First, the traditional intersection positioning model is improved by considering the equivalent sound velocity profile error as an unknown parameter in the adjustment model. Second, the effect of geometric dilution of precision (GDOP) on positioning accuracy is analyzed. By seeking for the minimum of GDOP, it is concluded that the absolute datum transfer can achieve the highest accuracy in the condition of sailing along a circle relative to other sailing paths. Moreover, the optimal radius of the circle for the accurate datum transfer is also given out. Besides, the correlation between the accuracy of datum transfer and the sound velocity error in this method is analyzed. Finally, the new method was tested and verified by the experiments in Songhua lake with the water depth of 60 m and in South China sea with the water depth of 2000 m, respectively. These experiment results show that the new method can improve the accuracy and efficiency of traditional datum transfer method significantly.     

Advantages of twin rudder system with asymmetric wing section aside a propeller

This study presents a new twin rudder system with asymmetric wing section, aside a propeller, as a new category energy saving device (ESD) for ships. The energy saving principle of the new ESD, which is called “Gate rudder”, is described and its applicability on a large bulk carrier is explored using experimental and numerical methods. The study makes emphasis on the cost-effectiveness of the proposed ESD and presents a potential energy saving up to 7–8 % with the new device as well as an attractive return investment in 0.37–0.9 year. These estimations are based on the conventional powering methods, whereas the accuracy of the ESD design method is confirmed by model test measurements.     

Oriented review to potential simulator for faults modeling in diesel engine

This paper presents a literature review on most of the faults and their models that are considered on a diesel engine. Several faults that may be produced on diesel engine have been analyzed, classified, modeled, and their influences on the global system have been shown. Thus, this paper aims to prepare an important data base on diesel engine faults which may help researchers to develop precise strategies on diesel engine fault diagnosis and prognosis, and also it helps in the development of diesel engine simulators aiming to study the behavior of the diesel engine in the presence of faults. Different fault models such as analytical, empirical, degradation models which may be represented as function of time or as function of the number of cycles, data driven models such as neural network models, or simply constant are presented and analyzed. The global overall models for diesel engine integrating faults are expressed. And finally, the use of these models with the most common failure density distribution functions is proposed giving a more realistic approach to our study.     

Large-eddy simulation of cross-flow around ship sections

The present work is motivated by phenomena occurring in the flow field around ship-like bodies with an incoming lateral flow (cross-flow, 90 ° drift angle). Three-dimensional unsteady flows around different ship sections are investigated by using computational fluid dynamic (CFD) tools with large-eddy simulation (LES) subgrid-scale turbulence model. The simulation results are compared to measurements at several Reynolds numbers in the 90–200,000 range. Focus in our investigation is on the characterization of the motion of vortex structures generated by the separated flow. Another target in the study is to obtain better knowledge of the hydrodynamic forces acting on the sections. Computed pressure and drag coefficients are compared with experimental measurements. The comparison between simulations and measurements shows that an LES model can predict the flow field around ship sections in detail and the hydrodynamic forces acting on the sections.