Measuring hierarchical differentiation: connectivity and dominance in the European urban network

Abstract

This paper presents an examination of the empirical merits of a set of spatial interaction indices for measuring hierarchical differentiation (i.e. dominance and connectivity) in a spatial network. To allow for the comparison of the degree of hierarchical differentiation in networks with different numbers of nodes/links, we propose to normalize the ratio between the real measures and the corresponding values for a rank size distribution in order to obtain readily interpretable measures of hierarchical differentiation. When applied to data on air passenger flows within Europe, the normalized indices, interpreted together, appear to give a good idea of the tendency toward hierarchical differentiation. The potential usefulness of this analytical framework is discussed in the context of studies on (transnational) inter-city relations and empirical assessments of changes in the spatial configuration of airline networks.     

Transport policy scenario-building

Long-term planning decisions must be as robust as possible to withstand such changes in the policy-making environment. This calls for a new approach for identifying how policies might fare under different types of conditions and for identifying robust no-regrets strategies. This paper outlines a systematic and logical framework for the development of policy scenarios and shows how scenarios can be used in the analysis of future policy options. The article discusses how scenario analysis can be used to identify, anticipate and assess policy options for the future in an environment of uncertainty, mainly using examples of transport policy in Europe.     

英国规范在钻孔灌注桩施工中的应用

结合EPC项目——斯里兰卡科伦坡外环高速公路的工程实践,从材料、施工、检测等方面,介绍以BS为主的国际规范在钻孔灌注桩施工中的应用,对区别于中国规范的重点和难点进行详细分析。     

沥青混合料车辙试验方法的对比分析

总结了目前世界上几种主流的车辙试验方法,包括我国的车辙试验方法 T0719—1993、基于APA的车辙试验方法 AASHTO TP 63-05、汉堡车辙试验方法 AASHTO T324-04、欧标的车辙试验方法 EN 12697-22。论述了不同方法之间的异同,主要从加载模式、试件成型方式、试验温度、评价方法等方面进行了深入分析,并对每种方法的代表性设备进行了对比分析。     

欧盟未来道路运输政策解析及启示

为研究新技术驱动下未来道路运输政策的变化,为我国新时期建设交通强国的科学决策提供支撑,通过实证分析等方法,选取欧盟道路运输业开展研究。从驱动道路运输转型发展的要素、未来道路运输转型发展的影响因素、新技术推动道路运输变革产生的经济社会影响等三个方面,阐述了欧盟未来道路运输业的变革和政策变化。在此基础上,根据我国交通运输发展实际,对行业管理提出建议,认为应及时跟踪国外有关“未来交通运输”的研究及技术部署;尽快建立与新技术、新业态相配套的交通运输法律法规、政策制度及监管体系;在未来的交通运输治理中加强公众参与,同时充分发挥科研机构、学（协）会等行业组织、企业等的作用。     

对欧盟最新客车法规2001/85/EC的理解与分析

欧盟强制性的客车结构安全法规2001/85/EC将于今秋生效,它是集客车结构安全法规的大成,也是国际化的客车法规范例。在制订我国客车标准和提高客车安全水平过程当中,深入理解欧盟的客车法规具有重要意义。     

Experimental investigation and comparison of nanoparticle emission characteristics in light-duty vehicles for two different fuels

In recent years, particle number emissions rather than particulate mass emissions in automotive engines have become the subject with controversial discussions. Recent results from studies of health effects imply that it is possible that particulate mass does not properly correlate with the variety of health effects attributed to engine exhaust. The concern is now focusing on nano-sized particles emitted from I. C. engines. In this study, particulate mass and particle number concentration emitted from light-duty vehicles were investigated for a better understanding of the characteristics of the engine PM from different types of fuels, such as gasoline and diesel fuel. Engine nano-particle mass and size distributions of four test vehicles were measured by a condensation particle counter system, which is recommended by the particle measurement program in Europe (PMP), at the end of a dilution tunnel along a NEDC test mode on a chassis dynamometer. We found that particle number concentrations of diesel passenger vehicles with DPF system are lower than gasoline passenger vehicles, but PM mass has some similar values. However, in diesel vehicles with DPF system, PM mass and particle number concentrations were greatly influenced by PM regeneration. Particle emissions in light-duty vehicles emitted about 90% at the ECE15 cycle in NEDC test mode, regardless of vehicle fuel type. Particle emissions at the early cold condition of engine were highly emitted in the test mode.     

Solving procurement problems in public transport: Examining multi-principal roles in relation to effective control mechanisms

Despite the EU’s increasing role in regulating public transport procurement, few studies have considered this aspect when analysing procurement problems of public transport. This paper examines how the institutional relationships between different actors, including international governmental bodies, in public transport effects the possibility of exerting control over a county public transport authority (PTA) in a multi-principal setting. The analysis is carried out using empirical material from an infringement process including a Swedish PTA and the EU. The conclusions have clear policy implications for the procedural order when exerting control over the PTA in cases of procurement problems. It is for example shown, that the implementation process would be much more efficient if the regulations allowed the EU to impose sanctions directly towards the local authorities without having to involve the national government when the procurement laws are violated.     

A constraint programming model with time uncertainty for cooperative flight departures

The lack of a proper integration of strategic Air Traffic Management decision support tools with tactical Air Traffic Control interventions usually generates a negative impact on the Reference Business Trajectory adherence, and in consequence affects the potential of the Trajectory-Based Operations framework. In this paper, a new mechanism relaying on Reference Business Trajectories as a source of data to reduce the amount of Air Traffic Controller interventions at the tactical level while preserving Air Traffic Flow Management planned operations is presented. Artificial Intelligence can enable Constraint Programming as it is a powerful paradigm for solving complex, combinatorial search problems. The proposed methodology takes advantage of Constraint Programming and fosters adherence of Airspace User’s trajectory preferences by identifying tight interdependencies between trajectories and introducing a new mechanism to improve the aircraft separation at concurrence events considering time uncertainty. The underlying philosophy is to capitalize present degrees of freedom between layered Air Traffic Management planning tools, when sequencing departures at the airports by considering the benefits of small time stamp changes in the assigned Calculated Take-Off Time departures and to enhance Trajectory-Based Operations concepts.