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).

Effects of the variability in the distribution of passenger luggage on the boarding policy

Citation

Fernandez, V. Lordan, O., Sallan, J. M. (2015). Effects of the variability in the distribution of passenger luggage on the boarding policy. 2015 ATRS World Conference. National University of Singapore (Singapore).

Abstract

Boarding time is one major concern when planning turnaround times in airline planning schedule. Some researchers (e.g. Steffen, 2008; Milne and Keyy, 2014) present methods to assign seats and to board passengers on an airplane that minimizes the total time to board. Steffen (2008) presents an optimum boarding method that assigns passengers to a specific numerical position in line that depends upon their ticketed seat location. Milne and Keyy (2014) assign individual passengers to seats based on the amount of luggage they carry. Although these methods give some interesting results, there are some aspects related to the luggage that haven’t been studied. For example, Milne and Keyy (2014) consider that each bin has unlimited storage space. For this reason, we have designed and implemented a simulation engine in order to analyze how the variability in the distribution of passenger luggage affects the total time to board all passengers. Our simulation engine considers a limited storage space, and take the parameters and distributions of the row-to-row times (triangular distribution) from the study of Van Landeghem and Beuselinck (2002). Moreover, we have included in the simulations the effect of different boarding policies that we have identified in the literature with several  distributions of the passanger luggage.

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.

Study of predictors of taxi times at BCN Barcelona-El Prat Airport

Citation

Valenzuela-Arroyo, M., Lordan, O., Sallan, J. M. (2014). Study of predictors of taxi times at BCN Barcelona-El Prat Airport. 2014 ATRS World Conference. KEDGE Business School, Bordeaux, France.

Abstract

PURPOSE
This study develops a model to predict taxi in and out times at Barcelona-El Prat Airport. The model includes a set of variables that take into account the aspects that can affect taxi times, such as control areas, operation hours, type of aircraft, and others.

METHODOLOGY
The study has been carried out using airport’s daily operational data for the months of June, July and August 2013. After filtering the information, several linear regression models have been built which provide a predicted value of taxi times as a function of the predictors taken into account.

ANTICIPATED RESULTS
The area predictors combined with the hour of operation explain more than the 75% of variance of taxi times. Also, predictor models show that taxi times are greatly dependent on the type of operation.
The taxi in model has a stronger predictive power than the taxi-out model. Taxi-in accounts for 76% of variance and the mean error of residuals is 0.48 min, while the same values for taxi-out model are 45% and 2.16 min, respectively. The reason to be of these differences is the uncertainty produced by waiting times at runway headers in taxi out models, a variable that cannot be controlled.

KEYWORDS
Taxi Times, Linear Regression Model, Predictor, Barcelona-El Prat Airport

A study of pooling of repairable parts inventory between operators

Citation

Lopez-Gracia, N., Lordan, O., Sallan, J. M. (2014). A study of pooling of repairable parts inventory between operators. 2014 ATRS World Conference. KEDGE Business School. Bordeaux, France.

Abstract

PURPOSE
The purpose of providing availability inventory service is to maximize aircraft utilization by keeping spare units ready to be installed whenever and wherever needed. Since the size of the fleet supported by the spare repairable components inventory is the most important driver, we model the closed-loop inventory system in which component failures are Poisson distributed and the repair times at the service facility are exponential.

METHODOLOGY
 The method is based on Palm’s theorem for recommending a repairable operative inventory for a fleet and the model estimates parts demand during a certain period. In this research, we develop an inventory model for a repairable parts system which is shared by different operators in order to quantify the advantages of managing a “pool” inventory instead of private inventories for each customer.

ANTICIPATED RESULTS
Analysis of key parameters suggests that to improve the availability of the system with repairable spare parts, the supplier should improve the components repair facility, rather than the base stock level.

KEYWORDS
Inventory pooling, Component reliability, Repair facility, Poisson distribution

Analysis of robustness of alliance route networks

Citation

Lordan, O., Sallan, J. M.; Simo, P., Gonzalez-Prieto, D. (2014). Analysis of robustness of alliance route networks. 2014 ATRS World Conference. KEDGE Business School. Bordeaux, France

Abstract

PURPOSE
This study analyzes the robustness of the three major airline alliances (Star Alliance, oneworld and SkyTeam) route network to unintended errors and intentional attacks. Robustness is assessed in two ways: with an edge-betweenness based vulnerability scale, and with the evolution of the size of the giant component as a function of number of disconnected nodes.

METHODOLOGY
Network robustness is assessed in several ways. First, it is proposed a normalization of a multi-scale measure of the vulnerability in order to compare the performance of networks with different sizes. Second, several adaptive strategies are proposed to minimize the size of giant component with a given fraction of disconnected nodes. Together with other approaches found in the literature, a node selection criterion based on network efficiency is introduced. Finally, it is described a new procedure -the inverted adaptive strategy- for sorting the nodes in order to anticipate the breakdown of a network.

ANTICIPATED RESULTS
Results show that Star Alliance has the most resilient route network, followed by SkyTeam and oneworld. Besides, the inverted adaptive strategy based on the efficiency criterion -inverted efficiency- shows a good performance to break networks, similar or even better than the adaptive strategy based on node betweenness.

KEYWORDS
Airline alliances, route networks, robustness, airport closure.

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

Antecedentes de enviar un manuscrito a una revista científica

Citación

Sunyer, Silvia; Sallan, Jose M; Simo, Pep; Trullas, Irene (2014). Antecedentes de enviar un manuscrito a una revista científica. Ponencia presentada en la 4ª Conferencia internacional sobre calidad de revistas en ciencias sociales y humanidades (CRECS 2014). Madrid, 8-9 de mayo.

Abstract

Enlace al abstract de la ponencia

Presentación

Enlace a la presentación de la ponencia