Decomposing travel times measured by probe-based traffic monitoring systems to individual road segments

In probe-based traffic monitoring systems, traffic conditions can be inferred based on the position data of a set of periodically polled probe vehicles. In such systems, the two consecutive polled positions do not necessarily correspond to the end points of individual links. Obtaining estimates of travel time at the individual link level requires the total traversal time (which is equal to the polling interval duration) be decomposed. This paper presents an algorithm for solving the problem of decomposing the traversal time to times taken to traverse individual road segments on the route. The proposed algorithm assumes minimal information about the network, namely network topography (i.e. links and nodes) and the free flow speed of each link. Unlike existing deterministic methods, the proposed solution algorithm defines a likelihood function that is maximized to solve for the most likely travel time for each road segment on the traversed route. The proposed scheme is evaluated using simulated data and compared to a benchmark deterministic method. The evaluation results suggest that the proposed method outperforms the bench mark method and on average improves the accuracy of the estimated link travel times by up to 90%.     

Material Selection for Hawsers for a Side-by-side Offloading System

In order to provide a theoretical guide for choosing the material for the hawsers for the FPSO side-by-side offloading system, which is moored by the yoke system, the 3D potential flow theory and full coupled time-domain analysis are presented to study the dynamic response of the offloading system. The MingZhu FPSO offloading system in the field BZ25-1 is simulated here; and four different characteristic fiber ropes are used as the material for the hawsers. To acquire an accurate hawser line tension, the polynomial fitting method is used to calculate the nonlinear stiffness of the hawsers. By comparing the hawser lines＇ tension and the relative motion between the FPSO and the shuttle tanker, a suitable material for the hawser lines is chosen and discussed in this paper. The results indicate that the nonlinear stiffness characteristic of the fiber rope has a small effect on the relative motion of the vessels, but the hawser lines＇ tension is greatly influenced by the different characteristics of the fiber ropes. The hawser lines＇ tension with nonlinear stiffness is in accordance with the one with the upper and lower bound linear stiffness, which proves this method of fitting the fiber ropes＇ nonlinear stiffness is reasonable and reliable.     

绢云母表面改性及其对环氧涂料防腐性能的影响

为了改善绢云母在环氧树脂涂料中的分散性,增强它与环氧树脂涂料的相溶性,用硅烷偶联剂(KH-550)对绢云母进行表面改性,并将改性后的绢云母用于环氧树脂涂料中.结果表明:通过偶联剂包覆改性后,绢云母在环氧树脂涂料中的分散性得到了提高,它与环氧树脂涂料的相溶性也得到明显提高,并且添加了改性后的绢云母的涂料防腐性能也得到了提高.     

上海逸仙高架NovaChip(R)超薄磨耗层降噪效果实测与分析

随着国家环境保护政策的完善,道路噪声日益成为环境保护工作及沿线居民关注的重点.道路工作者也在不断致力于低噪音沥青路面材料的研究.NovaChip 沥青路面是一种超薄粘结磨耗层,它采用间断级配.通过大空隙率达到防滑降噪的作用.介绍了NovaChip 的材料特性及其降噪机理,实测了NovaChip 试验路段的路面噪音并同其他路段进行比较,结果表明,NovaChip 的降噪效果明显.并且,由于其施工方便,可以在很短时间内开放交通,在城市薄层罩面中具有很好的应用前景.     

Sasobit改性沥青混合料的性能评价

Sasobit是目前较为广泛使用的一种新型改性剂。通过添加Sasobit前后沥青技术指标的对比测试发现,沥青在添加改性剂Sasobit后,软化点明显提高,针人度和低温延度有所下降且不同温度下的粘度均明显降低,从而可降低20～30℃的拌合成型温度,实现类似温拌的效果,使改性沥青混合料在保持热拌沥青混合料优良路用性能的同时,能有效降低施工过程中能源的大量消耗和有害气体的排放。在混合料性能方面,相比于普通热拌沥青混合料,Sasobit能大幅提高混合料的高温稳定性,但会略微降低低温抗裂性,且会明显降低其抗疲劳性能。     

基于OSEK的车用实时操作系统的设计与实现

根据OSEK/VDX规范,自主设计了一种车用嵌入式实时操作系统uOSEK.并从系统启动、任务调度和任务管理等方面,介绍了该系统的主要设计思想.最后通过在Freescale HC08平台上的实现,对uOSEK系统的实时性能和存储需求进行了评估.结果表明,该操作系统在8位机平台上具有较好的可行性,较强的实时性和较低的存储需求.     

信号交叉口转向可变车道长度研究

从信号交叉口服务水平和路权角度出发,提出了转向可变车道的概念,并且分析其设置的原则及条件。在此基础上,从交叉口的道路交通条件及通行效率方面考虑,建立了转向可变车道长度的最大值和最小值的计算模型。通过Vissim仿真模拟,从排队长度、延误和停车次数方面分析了转向可变车道的应用效果。     

口腔扁平苔癣患者红细胞免疫功能及发病机理的研究

采用酵母菌花环试验对３１例口腔扁平苔癣（ＯＬＰ）患者红细胞免疫粘附功能、循环免疫复合物、补体Ｃ３含量进行检测,并与正常组进行比较以研究患者红细胞免疫功能的改变与循环免疫复合物、补体Ｃ３含量的关系。结果表明：ＯＬＰ患者红细胞Ｃ３ｂ受体花环率、循环免疫复合物及补体Ｃ３含量均较正常组显著升高（Ｐ＜０．０１）。提示ＯＬＰ患者存在体液免疫紊乱及红细胞免疫功能代偿性增强。本实验为ＯＬＰ细胞介导的免疫损伤提供了又一证据,表明了红细胞免疫功能在口腔扁平苔癣发病机理及免疫防御中具有重要作用。     

铁路货车转向架静态模拟试验研究

通过分析通用铁路货车转向架的载荷承载结构,以及弹性旁承技术状态对转向架承载的影响,提出了货车转向架静态模拟性能试验的方案,并给出了运用该方案对转向架静态承载性能进行优化的操作方法.考虑到转向架承载情况会随货车运用过程不断变化,转向架静态模拟试验对于货车检修具有重要意义.     

港机金属结构故障诊断与安全使用期预估

1港口起重机金属结构故障诊断 金属结构的故障诊断是故障诊断工程领域的一个重点和难点,这是因为:①结构庞大,故障产生的部位很难确定;②开裂是结构最普遍的故障,它存在着潜在的危险;③金属结构折断是突发恶性故障,这种故障难于事前准确诊断.