Heuristics of node selection criteria to assess robustness of world airport network

Citation

Soria, M., Lordan, O.; Sallan, J. M. (2017). Heuristics of node selection criteria to assess robustness of world airport network. Chinese Journal of Aeronautics, 30(4), 1473-1480.
doi: http://dx.doi.org/10.1016/j.cja.2017.04.012
UPCommons: http://hdl.handle.net/2117/108021

Abstract

The world airport network (WAN) is one of the networked infrastructures that shape today's economic and social activity, so its resilience against incidents affecting the WAN is an important problem. In this paper, the robustness of air route networks is extended by defining and testing several heuristics to define selection criteria to detect the critical nodes of the WAN. In addition to heuristics based on genetic algorithms and simulated annealing, custom heuristics based on node damage and node betweenness are defined. The most effective heuristic is a multi-attack heuristic combining both custom heuristics. Results obtained are of importance not only for advance in the understanding of the structure of complex networks, but also for critical node detection.

Robustness of airline route networks

Citation

Lordan, Oriol; Sallan, Jose M; Escorihuela, Nuria; Gonzalez-Prieto, David (2015). Robustness of airline route networks, Physica A: Statistical Mechanics and its Applications, 445:18-26.

doi: http://dx.doi.org/10.1016/j.physa.2015.10.053

Abstract

Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

Analyzing the multilevel structure of the European airport network

Citation

Oriol Lordan, Jose M. Sallan (2017). Analyzing the multilevel structure of the European airport network. Chinese Journal of Aeronautics, 30(2):554-560.

doi: http://dx.doi.org/10.1016/j.cja.2017.01.013

Abstract

The multilayered structure of the European airport network (EAN), composed of connections and flights between European cities, is analyzed through the k-core decomposition of the connections network. This decomposition allows to identify the core, bridge and periphery layers of the EAN. The core layer includes the best-connected cities, which include important business air traffic destinations. The periphery layer includes cities with lesser connections, which serve low populated areas where air travel is an economic alternative. The remaining cities form the bridge of the EAN, including important leisure travel origins and destinations. The multilayered structure of the EAN affects network robustness, as the EAN is more robust to isolation of nodes of the core, than to the isolation of a combination of core and bridge nodes.

Dynamic robustness of the European air transport network

Citation

Melgosa, M., Lordan, O. Sallan, J. M., Fernandez, V., Gonzalez-Prieto, D. (2015). Dynamic robustness of the European air transport network. 2015 ATRS World Conference. National University of Singapore (Singapore)

Abstract

The analysis of the robustness of an air transport network (ATN) - i.e., its resilience facing the isolation of random airports (errors) and the isolation of central airports (attacks) - can be undertaken from an static or a dynamic perspective. The static perspective, that is, the impact on ATN connectivity of the long-term isolation of a set of airports, has been assessed in previous research (e.g., Lordan et al. 2014), but there are few attempts to assess the transitory effects on network connectivity of total or partial closure of one or several airports. Through simulation of the European ATN, we assess the impact of the closure of several central airports in a given moment of time, determining the fraction of cancelled flights, flight delays and assessing the possibility of cascading effects (saturation of other airports). Results shows that the European ATN is relatively robust facing the closure of a single airport. Future research aims to assess other consequences of total or partial airport closure (e.g., flight delays and delay propagation) and the impact of other ATN disruptions (closure of a flight information region or an area control center).

Robustness of regional air transport networks

Citation

Lordan, O., Sallan, J. M., Fernandez, V.; Gonzalez-Prieto, D. (2015). Robustness of regional air transport networks. 2015 ATRS World Conference. National University of Singapore (Singapore)

Abstract

The aim of this study is to compare the robustness of regional airline route networks (RARN) facing errors (random isolation of several airports) and attacks (isolation of central airports that may cause a major damage to network connectivity). Nodes of RARN are airports of a region, and there is an edge for each pair of airports connected by a direct flight (Zannin and Lillo, 2013). The regions analyzed are Africa, Asia, Australasia, Caribbean, Central America, Europe, Middle East, and North and South America. It has been proven that the topology of airline route networks makes them resilient to errors, but vulnerable to attacks(Guimerà et al., 2004, 2005). Robustness to errors is assessed through several simulations of random node isolation are performed, and robustness to attacks through several node selection criteria (Petreska et al, 2010). Network resilience is assessed through the decrease of the size of giant component as a function of the fraction of isolated nodes, and through a normalized vulnerability index based on edge betweenness (Boccaletti et al., 2007, Lordan et al., 2015). Results show that air global network regions have quite different values of resilience, being the Asian and European networks the more robust, and Australasia and Middle East the less resilients.

Robustness of airline alliance route networks

Citation

Lordan, O., Sallan, J. M., Simo, P., Gonzalez-Prieto, D. (2014). Robustness of airline alliance route networks. Communications in Nonlinear Science and Numerical Simulation, 22, 587-595.
http://dx.doi.org/10.1016/j.cnsns.2014.07.019

Abstract

The aim of this study is to analyze the robustness of the three major airline alliances’ (i.e., Star Alliance, oneworld and SkyTeam) route networks. Firstly, the normalization of a multi-scale measure of vulnerability is proposed in order to perform the analysis in networks with different sizes, i.e., number of nodes. An alternative node selection criterion is also proposed in order to study robustness and vulnerability of such complex networks, based on network efficiency. And lastly, a new procedure – the inverted adaptive strategy – is presented to sort the nodes in order to anticipate network breakdown. Finally, the robustness of the three alliance networks are analyzed with (1) a normalized multi-scale measure of vulnerability, (2) an adaptive strategy based on four different criteria and (3) an inverted adaptive strategy based on the efficiency criterion. The results show that Star Alliance has the most resilient route network, followed by SkyTeam and then oneworld. It was also shown that the inverted adaptive strategy based on the efficiency criterion – inverted efficiency – shows a great success in quickly breaking networks similar to that found with betweenness criterion but with even better results.

Study of the robustness of the European air routes network

Citation

Lordan, O., Fernandez, V., Sallan, J.M. and Simo, P. (2014). Study of the robustness of the European air routes network. 4th International Conference on Logistics, Informatics and Service Science (LISS 2014). University of California – Berkeley (USA).

Abstract

The aim of this study is to analyze the robustness of the European civil European air transportation network from the perspective of the theory of complex networks. This study is based on analyzing the behavior of the network when its nodes (airports) are removed either by random errors or by deliberate attacks. The calculation of network statistical indicators as degree and betweenness distribution reveals that the flight flow network has the small-world characteristics and scale-free property. The selection of nodes on deliberate attacks is based on four centrality criteria: degree, betweenness, pagerank and eigenvector. This study aims to contribute to the understanding of the logistics network of European commercial flights, analyzing its strengths and weaknesses.

Conference presentation

This post of the Vicenc Fernandez website contains a video of the presentation at the LISS conference

Robustness of the air transport network

Citation

Lordan, O.; Sallan, J. M.; Simo, P.; Gonzalez-Prieto, D. (2014). Robustness of the air transport network. Transportation research part E: Logistics and transportation review, 68:155-163
http://dx.doi.org/10.1016/j.tre.2014.05.011

Abstract

This paper presents a methodology for the detection of critical airports (those whose isolation would cause the largest losses in network connectivity) in the global air transport network (ATN), based on simulating an attack on selected ATN airports using different adaptive selection criteria. The performances of several node selection criteria are compared, together with a new criterion based on Bonacich power centrality. The results show that most critical airports can be detected with an adaptive strategy based on betweenness centrality. The detection of such airports may help the development of contingency plans to develop an appropriate response to any airport closure.

Study of the topology and robustness of airline route networks from the complex network approach: a survey and research agenda

Citation

Lordan, O., Sallan, J. M., Simo, P. (2014). Study of the topology and robustness of airline route networks from the complex network approach: a survey and research agenda. Journal of Transport Geography, 37:112-120.
http://dx.doi.org/10.1016/j.jtrangeo.2014.04.015

Abstract

Communication via air routes is an important issue in a world organized around a web city network. In this context, the robustness of network infrastructures, e.g. air transport networks, are a central issue in transport geography. Disruption of communication links by intentional causes (e.g., terrorist attack on an airport) or unintentional (e.g., weather inclemency) could be crucial for countries, regions and even the airlines affected themselves. Policymakers and the management of airlines and alliances should be able to reduce the effects of such interruptions in order to ensure good communication through air transport (i.e., maximize the robustness of their network at a reasonable cost). The literature review of the study of air transport route networks through an analysis of complex networks has highlighted a lack of contributions to the study of the topology and the robustness of such networks which contrasts, with advances undertaken for other transport networks or communication systems. This survey suggests areas in which research should be undertaken, based on the existing literature in other areas and from three different perspectives: global route networks, airline alliances, airlines and airports so as to help towards a better understanding of air traffic and, therefore, to be able to assess the potential damage of any airport being inoperative for a continent, country or airline.

Airline route networks: A complex network approach

Author

Oriol Lordan

Supervisors

Jose M Sallan, Pep Simo

Defense date

14th April, 2014

Abstract

Communication via air routes is an important issue in a world organized around a web-like city network. In this context, the robustness of network infrastructures, e.g. air transport networks, is a central issue in transport geography. Disruption of communication links by intentional causes (e.g., terrorist attack on an airport) or unintentional (e.g., weather inclemency) could be a serious drawback for countries, regions or airlines. Policymakers and the management of airlines and alliances should be able to reduce the effects of such interruptions in order to ensure good communication through air transport, that is, to maximize the robustness of their network at a reasonable cost. The literature review of the study of air transport route networks through complex networks has highlighted a lack of contributions to the study of the topology and the robustness of such networks, which contrasts with advances undertaken for other transport networks or communication systems. The literature survey suggests areas in which research should be undertaken, based on the existing literature in other areas and from three different perspectives: global route networks, airline alliances and airlines. The aim of this research is to develop a better understanding of air traffic and, in particular, to be able to assess the potential damage of any airport being inoperative for a continent, country or airline. This thesis analyzes the topology and robustness of three proposed levels of study characterized by different units of analysis: global route network, airline alliances route network and airlines route network. The different levels do not only represent networks of different magnitudes in number of nodes (airports) and links (routes), but also represent different approaches. In Chapter 2 robustness of the global air transport network (L1) has been analyzed and criteria based on Bonacich power centrality has been presented in order to assess attack vulnerability of complex networks. One of the outcomes of this study will be a list of the most critical airports for the vulnerability of the entire air transport network. In Chapter 3 robustness of alliances route network (L2) will be assessed comparing the robustness of the three major airline alliances (Star Alliance, oneworld and SkyTeam). To perform this analysis, one new node selection criterion based on the efficiency of networks and one new method of assessing vulnerability will be presented. This analysis will lead also to a comparison of the robustness of the three alliances. Finally, in Chapter 4 robustness of 10 FSCs and 3 LCCs route network (L2) will be analyzed. The studied FSCs belong to the different airline alliances showed in Chapter 3 thus allowing the comparison among levels. This chapter outlines a comparison of the differences in robustness between FSCs and LCCs. In Chapter 5 a summary and discussion of conclusions obtained for each level will be carried out.

Thesis contents

The complete text of this thesis can be dowloaded at the TDR repository in the following link: http://www.tdx.cat/handle/10803/144526

Study of the evolution of routes operated by an airline going into bankruptcy: the case of Spanair

Student

Cristina Alemany

Supervisors

Oriol Lordan / Jose M Sallan

Defense date 

11th Abril, 2014

Abstract

The aim of this project is to analyze the competitive dyamics that evolve when an airline goes bankrupt. The cease of operations of the bankrupt airline gives an opportunity to the rest of airlines to increase the market share of the routes covered by the airline. If the bankrupt airline belongs to an alliance, these routes may be covered by other members of the aliance, competitors or airlines operating on a point-to-point basis.

This project analyzes in depth the case of Spanair, an Spanish airline went bankrupt on January 2012. The route portfolio of the company of the period January 2010 - January 2012 is considered for analysis. Results shows that LCCs (Vueling and Ryanair) and FSC from onewold (Iberia) and SkyTeam (Air Europa) absorbed the market share left by Spanair. Other companies from Star Alliance absorbed a fraction of the international routes of Spanair, but none of the domestic routes. Currently Star Alliance has a weak position in Spain, since there is no local airline in this alliance.

Study of the Robustness of the European Air Routes Network

Citation

Lordan, O., Florido, J., Sallan, J. M., Fernandez, V., and Simo, P. Gonzalez-Prieto, D. Study of the Robustness of the European Air Routes Network (February 26, 2014). Available at SSRN: http://ssrn.com/abstract=2401696

Abstract

The aim of this study is to analyze the robustness of the European civil European air transportation network from the perspective of the theory of complex networks. This study is based on analyzing the behavior of the network when its nodes (airports) are removed by random attacks and deliberate attacks. The selection of nodes on deliberate attacks is based on four criteria: degree, betweenness, pagerank and eigenvector. This study aims to contribute to the understanding of the logistics network of European commercial flights, analyzing their strengths and weaknesses. The calculation of network statistical indicators as degree and betweenness distribution reveals that the flight flow network has the small-world characteristics and scale-free property.