Increasing the resilience of air traffic networks using a network graph theory approach

Air traffic networks are essential to today’s global society. They are the fastest means of transporting physical goods and people and are a major contributor to the globalisation of the world’s economy. This increasing reliance requires these networks to have high resilience; however, previous events show that they can be susceptible to natural hazards. We assess two strategies to improve the resilience of air traffic networks and show an adaptive reconfiguration strategy is superior to a permanent re-routing solution. We find that, if traffic networks have fixed air routes, the geographical location of airports leaves them vulnerable to spatial hazard.     

EU involvement in TEN development: network effects and European value added

The recent White Paper emphasises once more that the Trans-European transport network (TEN) is a key element in European Union (EU) policy, yet that its realisation is jeopardised by the lack of an integrated approach during evaluation and funding of cross-border infrastructure. Despite the intervention of the EU in conceptualising the TEN, subsidiarity and continued use of conventional evaluation procedures mean that most assessment of individual TEN components is still undertaken in relatively narrow, national terms. The primary objective of this paper is to explore how the international character of the TEN may be recognised and incorporated in still predominantly national evaluation processes, and which evaluation horizons may be broadened based on the concepts of network effects and European value added (EVA). We present some examples of EVA and discuss EU involvement in projects with potentially high EVA, either by co-ordinating bilateral negotiations for compensation between Member States or by co-financing projects that support the achievement of strategic EU transport policy objectives.     

Evolution of the international air transportation country network from 2002 to 2013

In this research, we analyze the evolution of the international air transportation country network from 2002 to 2013 with two perspectives: The network’s physical topology and the functional network with traffic information. Our analysis shows that the network is scale-free and has the small-world property. The evolution of triadic properties suggests that the network gears towards symmetric, transitive closure. We find that United States, Great Britain, and France are critical from both perspectives; Surprisingly, South Africa is particularly critical from topological point of view. Furthermore, topological and functional criticality are highly correlated to the GDP of a country.     

Marrying supply chain sustainability and resilience: A match made in heaven

Sustainable supply chain management has become an integral part of corporate strategy for virtually every industry. However, little is understood about the broader impacts of sustainability practices on the capacity of the supply chain to tolerate disruptions. This article aims to explore the sustainability–resilience relationship at the supply chain design level. A multi-objective optimization model featuring a sustainability performance scoring method and a stochastic fuzzy goal programming approach is developed that can be used to perform a dynamic sustainability tradeoff analysis and design a “resiliently sustainable” supply chain. Important managerial and practical insights are obtained from an empirical case study.     

Performance measurement of a transportation network with a downtown space reservation system: A network-DEA approach

We propose an evaluation approach for a novel travel demand management strategy known as the downtown space reservation system (DSRS). This approach takes into account three perspectives, i.e., transportation service provider’s, the user’s, and the community’s and is based on network-Data Envelopment Analysis (DEA) where the perspectives are inter-related through intermediate inputs/outputs. Two types of network-DEA models (radial and slacks-based models) are considered. An example is provided using data propagated from a microscopic traffic simulation model of the DSRS. The results show that individual node performance can drive network DEA performance and that this information can inform future designs of the DSRS.     

我国西北地区铁路网络可靠性研究

我国西北地区铁路网络密度较低,如果线路或车站发生故障导致行车中断,对铁路运输影响较大。以我国西北地区普速铁路和高速铁路为研究对象,根据主要城市的铁路客运量、人口和GDP等综合因素,选取40个城市作为节点,基于SpaceL空间构建西北地区物理网络,计算我国西北地区铁路网络的度分布和中介中心性。采用单个节点攻击、蓄意ID攻击、蓄意RD攻击3种模拟方法计算节点失效后网络的全局效率,以分析西北铁路网络的可靠性。结果表明,西安、兰州、嘉峪关、中卫和咸阳对西北地区铁路网络的可靠性影响较大,应优先加强这些重要节点的连通性,以提升铁路网络的可靠性。     

Variations in hub service in the US domestic air transportation network

This paper looks at the various types of hubs that have evolved in the air transportation network in the USA. Since deregulation of the industry at the end of the 1970s, the major air carriers have expanded their networks to become more competitive, and the number and types of hubs have grown accordingly. A connectivity analysis using a traditional matrix approach is used to derive indices which are the basis for the development of a connectivity classification scheme. In addition, the various service functions of hubs are explored.     

A network-based analysis of the impact of structural damage on urban accessibility following a disaster: the case of the seismically damaged Port Au Prince and Carrefour urban road networks

The magnitude 7.0 earthquake that struck Haiti in January 2010 led to an unprecedented effort in collecting and providing geographical information in support of humanitarian aid. Although most of the compiled datasets and generated maps were able to provide specific and detailed information regarding the location of damaged buildings and road interruptions, none or little information was available to describe the accessibility—or otherwise—of the urban space. Here we try to offer an alternative method to define the urban accessibility landscape in the aftermath of earthquake damage, by combining simple graph theory concepts and GIS-based spatial analysis to assess how the urban space accessibility decreases when the road network is damaged.     

高速铁路网规划和运输组织的理论与实践初探

根据高速铁路的技术特征,对高速铁路、城际铁路的线路走向、车站及站场布局、与其他交通方式无缝化衔接、主要通道客货分线运输、旅客列车运输组织协调等因素进行了分析,对高速铁路路网规划、运输组织理论作了初步探讨,并对高速铁路网规划建设和运输组织实践作了简要分析。     

Supply chain network competition in price and quality with multiple manufacturers and freight service providers

In this paper, we develop both static and dynamic supply chain network models with multiple manufacturers and freight service providers competing on price and quality. The manufacturers compete with one another in terms of price and quality of the product manufactured, whereas the freight service providers compete on price and quality of the transportation service they provide for multiple modes. Both manufacturers and freight service providers maximize their utilities (profits) while considering the consequences of the competitors’ prices and quality levels. Bounds on prices and quality levels are included that have relevant policy-related implications. The governing equilibrium conditions of the static model are formulated as a variational inequality problem. The underlying dynamics are then described, with the stationary point corresponding to the variational inequality solution. An algorithm which provides a discrete-time adjustment process and tracks the evolution of the quality levels and prices over time is proposed, and convergence results given. Numerical examples illustrate how such a supply chain network framework, which is relevant to products ranging from high value to low value ones, can be applied in practice.     

Factors influencing the location of new motorways: large scale motorway building in Spain

Since the 1980s Spain has developed an ambitious road building programme with the construction of approximately 12,000 km of new motorways. This article analyses the factors related to the placement of these new motorways during two distinct planning periods from 1983 to 1993 and 1994 to 2004. Motorway placement strongly followed the existing radial road network dating back as far as the eighteenth century which illustrates the critical role that past decisions play in the placement of new investment. Motorway placement was also significantly related to population size and, more in general, the urban system. The empirical analysis, however, provides little evidence that motorways were placed in response to local economic growth.     

Cooperatives for fruits and vegetables in emerging countries: Rationalization and impact of decentralization

We develop a (noncooperative) game theoretic model for a decentralized setting wherein fringe farmers compete with a two-tier cooperative network involving network farmers and a coordinator. We examine the roles of the coordinator and profit sharing in allocating costs/benefits of externalities in enhancing network efficiency and stability. Our main finding is that using profit sharing based mechanism the coordinator can overcome inherent inefficiency and instability of decentralization and noncooperative behavior of the network farmers. The roles of the coordinator and profit sharing are particularly important when it is economical for both network and fringe farmers to supply the product.     

CAFTA框架下广西交通的经济相关性

随着中国-东盟自由贸易区的建立,广西将在中国与东盟各国的经贸交往中发挥重大作用。根据区域经济与区域交通运输相适应的关系,搜集广西经济、贸易、交通等发展情况的有关数据并进行线性回归分析,对CAFTA下广西交通适应性做出评价。目前广西交通滞后于双边贸易增长带来的需求,尤其表现在铁路系统。应该加大对广西铁路基础设施的投资建设,更好地促进中国-东盟自由贸易区的发展。     

铁路第六次大面积提速在优化运力资源配置扩大运输能力方面取得的成果

铁路运输部门利用既有线提速资源,发挥以动车组为代表的新技术装备优势,挖掘路网潜力,开展运输组织创新,编制完成“4.18”全路第六次大面积提速调图工作,全路车流径路、编组计划、运输组织、机车运用等得到全面优化,客货产品更趋丰富完善,客货服务全面创新,客货能力大幅增长,运输生产得到了进一步释放,为国民经济又好又快地发展将发挥积极的作用。     

Optimisation of the exploitation period of individual vehicles in freight transportation companies

The individual vehicle replacement problem typical for freight transportation companies is discussed in the paper. Two characteristic features of such problem are that transportation companies utilise vehicles with intensity decreasing with an age of vehicles and that managers of such companies first of all take into account economical criteria when planning vehicle replacements. The paper presents a single criterion, nonlinear, deterministic and discrete mathematical model of such a problem that minimises a total exploitation and ownership costs calculated per kilometre. The exact solution procedure is proposed here. The problem is solved as a real life case study. As a result, an average, economically optimal 5-year exploitation period of vehicles has been determined.     

Changes in accessibility in the Meseta Purépecha region of Michoacán, Mexico: 1940–2000

This paper examines changes in town accessibility on the Meseta Purépecha of Michoacán, Mexico before and after road construction beginning in the 1940s. In the mid-20th century researchers noted the presence of an important mountain–lake trade connection, which by 2000 had been significantly diminished. Between 1940 and 2000 there was an increase in accessibility of the area east of Lake Pátzcuaro, while there were more modest increases seen in the western section of the meseta. Road improvements and realignments have led to substantial changes in the theoretical network associations among the towns, and while towns in the region have become better connected externally, improvements in accessibility among towns within the region were unevenly distributed.     

Defining and monitoring the quality of shared-use transportation facilities in parks and recreation areas

Transportation networks in parks and recreation areas provide travelers recreation opportunities and often support multiple transportation modes (e.g., hiking, walking, biking). In recreation areas, the quality of transportation service may be monitored and evaluated differently than in traditional transportation contexts. However, few studies have examined approaches for defining and monitoring the quality of transportation service and recreation experiences. This study applies traffic monitoring models to monitor (1) the quality of transportation service through the Levels of Service (LOS) framework and (2) travelers’ recreation experiences through the indicators and standards framework simultaneously on the Burlington Bike Path (BBP), a typical shared-use transportation recreation facility in Vermont. Results identify the temporal pattern of visitors use and the mode splits between cyclists and pedestrians. Moreover, study results show that the majority of travelers use the BBP for recreation or mixed purpose of recreation and commute. Study results build quantitative relationships between LOS and indicators and standards of quality that will help inform management of transportation in the context of recreation. The indicators and standards framework can help define the thresholds of acceptable levels of transportation service through the LOS framework. The relationships between LOS and the indicators and standards framework help build a robust and fully parameterized transportation planning and management framework for parks and recreation areas. Study results suggest quantitative guidelines that can be used to evaluate and monitor the quality of transportation performance for shared-use paths in parks and recreation areas.     

新建铁路社会效益计算方法的探讨

由于新建铁路对社会经济的贡献缺乏有效的定量化计量手段,结果常常是铁路对社会经济所起的作用被低估。为此通过抽样调查和统计分析的广义成本分布模拟的计量方法对铁路运输创造的消费者剩余进行定量化计算,铁路对社会其他方面的贡献也可参照这种方法和思路进行定量化计量。