Optimal route decision with a geometric ground-airborne hybrid model under weather uncertainty

Adverse weather is the dominant cause of delays in the National Airspace System (NAS). Since the future weather condition is only predictable with a certain degree of accuracy, managing traffic in the weather-affected airspace is a challenging task. In this paper, we propose a geometric model to generate an optimal combination of ground delay and route choice to hedge against weather risk. The geometric recourse model (GRM) is a strategic Probabilistic Air Traffic Management (PATM) model that generates optimal route choice, incorporating route hedging and en-route recourse to respond to weather change: hedged routes are routes other than the nominal or the detour one, and recourse occurs when the weather restricted airspace becomes flyable and aircraft are re-routed to fly direct to the destination. Among several variations of the GRM, we focus on the hybrid Dual Recourse Model (DRM), which allows ground delay as well as route hedging and recourses, when the weather clearance time follows a uniform distribution. The formulation of the hybrid DRM involves two decision variables - ground delay and route choice - and four parameters: storm location, storm size, maximum storm duration time, and ground-airborne cost ratio. The objective function has two components: expected total ground delay cost and expected total airborne cost. We propose a solution algorithm that guarantees to find the global optimum of the hybrid-DRM. Based on the numerical analysis, we find that ground-holding is effective only when combined with the nominal route. Otherwise, it is optimal to fly on the route determined by the DRM without ground delay. We also find the formula of the threshold ground-airborne cost ratio, which we call the Critical Cost Ratio (CCR), that determines the efficacy of ground delay: the higher the CCR, the more effective the strategies involving ground delay. We conclude that both ground delay and route hedging should be considered together to produce the best ATM decisions.     

践行科学发展观,努力构建和谐公路

文章结合公路部门的实际和发展现状,从构建和谐公路的重要性和必要性出发,对如何围绕公路养护工作,不断提高公路部门的服务能力,提高文明建设的水平,树立公路部门在社会中的良好形象等问题进行一些有益的探讨.     

浅谈公路路基常用排水设施设计

水是影响路基工程质量的重要因素。就路基病害的规模、范围及成因而言,水往往是决定性的因素之一。因此路基常用排水设计,是路基设计必不可少的项目和内容。     

公路养护管理站职工思想政治教育方式的思考

公路养护管理站是公路行业的细胞,其职工思想政治教育效果直接关系公路部门能否当好国民经济发展的先行官。在新的形势、新的任务和新的挑战面前,如何解放思想、更新观念、与时俱进,在继承和发扬思想政治工作优良传统的基础上,努力创新思想政治教育方式,更加贴近实际、贴近群众、贴近生活地开展公路养护管理站职工思想政治教育工作,是基层公路政工干部的重要课题。     

浅谈山区高速公路生态规划及恢复技术措施

随着西部大开发战略的实施,我国高速公路建设逐渐向山区推进。山区地形复杂,路线平纵面指标变化明显,桥隧结构物比例较大,这些都增加了高速公路基础设施设计的难度。     

Traffic density,congestion externalities,and urbanization in China

ABSTRACT

Although there is an abundant regional literature analyzing traffic congestion, only a few studies have explored extending such analysis with spatial effects. This study uses a dynamic spatial Durbin model and city-level panel data for the period 2003–14 to investigate the spatial spillover effects of traffic congestion on urbanization in China. The results show that there is an inverted ‘U’-shaped relationship between urbanization and traffic density in local and neighbouring cities, and congestion effects have appeared. In the short and long run, the spatial effects of traffic congestion have become an important force restricting the effective promotion of urbanization in China.     

Vector network equilibrium problems with capacity constraints of arcs

In this paper, we study a (weak) vector equilibrium principle with capacity constraints of arcs and common arcs in some different paths. We obtain some necessary and sufficient conditions for a (weak) vector minimum cost flow. By virtue of a (weak) Δ-equilibrium principle, we also derive some necessary and sufficient conditions for a weak vector equilibrium flow.     

Effect of driver,roadway, collision,and vehicle characteristics on crash severity: a conditional logistic regression approach

The aim of the study is to examine the factors that appear to have a higher potential for serious injury or death of drivers in traffic accidents in Turkey, such as collision type, roadway surface, vehicle speed, alcohol/drug use, and restraint use. Driver crash severity is the dependent variable of this study with two categories, fatal and non-fatal. Due to the binary nature of the dependent variable, a conditional logistic regression analysis was found suitable. Of the 16 independent variables obtained from Turkish police accident reports, 11 variables were found most significantly associated with driver crash severity. They are age, education level, restraint use, roadway condition, roadway type, time of day, collision location, collision type, number and direction of vehicles, vehicle speed, and alcohol/drug use. This study found that belted drivers aged 18–25 years involving two vehicles travelling in the same direction, in an urban area, during the daytime, and on an avenue or a street have better chances of survival in traffic accidents.     

大型交通重点项目党建统管制工作创新研究

党建统管制是大型交通重点项目的党建新模式。但面对新形势，这一工作模式也需要进一步创新。要从加强在建项目党组织的建设管理、积极搭建和充分利用与施工所在地党建联动平台、注重党组织文化建设、正确处理党建统管制工作与大型交通重点项目建设之间的辩证关系等方面来加强和优化大型交通重点项目党建统管制工作，促其在实践中得到充分的运用，保证优质、安全、高效、廉洁地完成重大交通建设项目。     

机动车强制责任保险中受害人直接请求权问题的思考

受害人直接请求权制度是机动车强制责任保险法制的核心和关键之一,对该制度相关问题的思考和明确,有利于更好地实现交强险保护受害人利益的初衷和理念,同时对于我国今后完善相关立法也有相应的参考意义。