Sight distance analysis of highways using GIS tools

Analyzing the distance visible to a driver on the highway is important for traffic safety, especially in maneuvers such as emergency stops, when passing another vehicle or when vehicles cross at intersections. This analysis is necessary not only in the design phase of highways, but also when they are in service. For its use in this last phase, a procedure supported by a Geographic Information System (GIS) has been implemented that determines the highway distances visible to the driver. The use of a GIS allows the sight distance analysis to be integrated with other analyses related to traffic safety, such as crash and design consistency analyses. In this way, more complete analyses could be made and costs shared. Additionally, with the procedure proposed it is possible to use data regarding the trajectory of a vehicle obtained on a highway with a Global Positioning System (GPS) device. This application is very useful when highway design data are not available. The procedure developed and its application in a case study are presented in this article.     

DEUS BOBBERSAKE V1

澳大利亚的改装商Deus算是令Vintage风格复古改装再度流行的始作俑者之一,他们的作品多是1940～1970年代流行的风格,比如Bobber。用于改装的车辆一般是在产在售的复古车型,强调手工金属质感。Deus同时也经营复古风格的服装和冲浪板,设计风格也是比较怀旧的澳大利亚海滩风格。摩托车对于Deus来说不单单是一个交通工具,还是一种生活方式。     

基于因子叠加法的滑坡灾害危险性区划——以衡桂高速公路为例

滑坡灾害危险性区划是将区域内产生滑坡灾害的发生条件、外界影响因素、和滑坡灾害的现状进行综合统计分析,定量或半定量地评价区域内滑坡灾害的危险性程度等级。选择湖南省衡桂高速公路滑坡灾害的分类与区划为研究示范区,对衡桂高速公路沿线滑坡灾害进行危险度研究,采用因子叠加法进行滑坡灾害区划。     

基于支持向量机的船舶操纵运动在线建模

支持向量机算法以结构风险最小化为准则,具有良好的泛化性,是一种先进的人工智能算法。文章根据最小二乘支持向量机对其增量式算法进行推导,并应用该算法对船舶操纵运动进行在线建模。通过仿真试验对粘性力和舵力水动力导数进行在线辨识,通过自航模试验对操纵性K、T指数进行在线辨识,并利用K、T指数对自航模的转首角速度进行了预报,所得结果都同试验值非常接近,证明了增量式最小二乘支持向量机应用于船舶操纵运动在线建模的有效性。     

Method for obtaining the modal properties of articulated trains equipped with independently rotating wheels

Independently rotating wheels in railway vehicles could represent an alternative to standard technology as a solution to dynamic problems such as hunting instability or steering forces in curves. Among the proposed design solutions, the train with independently rotating wheels and with the most practical applications is that developed by Talgo. The Talgo technology is based on the use of a passive steering technique of the wheelset through a mechanism. The absence of automatic control systems means that a careful selection of the mechanical parameters of the vehicle is required to improve its dynamic characteristics. Aspects such as dynamic stability or the effect of vibration on passenger comfort could be analysed by extracting the modal properties of the train from mathematical models. In this article, a methodology for determining the low-frequency modal properties of articulated trains equipped with independently rotating wheels and passive steering system (Talgo-type) is proposed. The singularity of this application based on the use of non-conventional wheelsets necessarily involves the development of a specific methodology.     

The contribution of total suspended solids to the Bay of Biscay by Cantabrian Rivers (northern coast of the Iberian Peninsula)

Information of suspended sediments fluxes of small rivers to the coastal zone is sparse, and this is particularly so for the Iberian Rivers. To help address this shortage of information, the relationship between fluvial discharge and total suspended solids (TSS) for the main 28 Cantabrian Rivers using data from 22 years monitoring by the COCA network has been analysed, and their particulate material fluxes to the Bay of Biscay coasts have been quantified. The Cantabrian Fluvial System (drainage basin area of 20,333 km²) may be considered as a quasi-homogeneous fluvial system with an average discharge of 561 m^− 3 s^− 1 and average loads of 35 kg_TSS s^− 1 with rivers showing similar average yields of 56 t km^− 2 a^− 1. The average TSS contribution is 1.2 ± 0.2 10⁹ kg a^− 1. This seaward flux of sediment is dispersed along the entire North Iberian coast and is rather modest (25% of the total supply) in comparison with the output from the French Rivers to the Bay of Biscay. The TSS loads of Cantabrian Rivers indicate they are similar to world upland rivers and those of other parts of Northern Europe according to Milliman and Syvistki [Milliman and Syvistki, 1992. Geomorphic/tectonic control of sediment discharge to the ocean: the importance of small mountainous rivers. Journal of Geology, 100: 525–544] and Milliman [Milliman, 2001. Delivery and fate of fluvial water and sediment to the sea: a marine geologist's view of European rivers. Scientia Marina, 65: 121–132]. Although their TSS flux is practically negligible (13,000 times lower) when compared to the world average flux, they provide a good example of the role of small Atlantic temperate rivers.     

A multiple criteria approach for the evaluation of the rail transit networks in Istanbul

The deficiencies in the Istanbul transportation system have led the local authorities to plan several alternative transportation projects. In this paper three alternative rail transit network proposals are evaluated by using Analytic Hierarchy Process (AHP), a multiple criteria decision support system. The AHP facilitates decision-making by organizing perceptions, experiences, knowledge and judgments, the forces that influence the decision, into a hierarchical framework with a goal, scenarios, criteria and alternatives of choice. Based on this analysis, the decision makers have developed a new alternative as a combination of the most closely competing two alternative rail transit networks. This combination rail transit network is currently under construction.     

车身结构件多步冲压工艺数值模拟

分析了左后悬挂架形成特点，采用两步拉延方式完成成形；然后确定首次拉延的四种方案，研究不同变形形式和变形量对后继拉延所造成的成形质量的影响；通过数值模拟结果中的FLD曲线、材料厚度分布图、最大主应变分布图和拉延成形变形裕度，研究车身结构件多步冲压工艺设计。     

A multioutput cost function for the services of Spanish ports' infrastructure

A long run multioutput cost function for the infrastructure services of Spanish ports is estimated using 286 observations on 26 ports during 11 years. Cargo specific marginal costs and the degree of economies of scale and scope are calculated up to a port level. Results show that liquid bulk and non-containerised general cargo present the lowest and largest marginal cost, respectively. Increasing returns to scale are present in general and for each and every port. A scope analysis indicates that port specialisation is not appropriate from the viewpoint of infrastructure.     

Chaotic Motion of Wheels

Trolleys have wheels which can choose the direction of their rolling. Studying the motion of a wheel like this, we can often find periodic motions (“shimmy”) or even chaotic ones. It has also been experienced that the chaotic motions sometimes disappear quite unexpectedly. A strongly simplified model of these systems is analysed in the paper by means of the methods of bifurcation theory. Analytical and numerical results are shown to characterize the system, including simulation results. Similar behaviour can be found in more complicated systems as well, like the trailers or the nose-gears of aeroplanes. The development of the so-called transient chaotic motion is explained in these systems.