This paper provides a tool to identify key aspects for an airport to achieve global hub status for a given airline and determines whether these factors are related to the facility’s infrastructure,its region,or both....This paper provides a tool to identify key aspects for an airport to achieve global hub status for a given airline and determines whether these factors are related to the facility’s infrastructure,its region,or both.Despite the frequent use of the term‘hub’,there is little academic consensus on its exact definition in air transport.Many define a hub based on passenger numbers rather than the concentration of flights and passengers from the main carrier.This study addresses this gap by analyzing the factors influencing the definition of a hub and the commonalities among global hubs.Data from 300 major airports,including internal variables(runways,terminals,gates and area)and external variables(economy,population,attractiveness),were collected.A Binary Logistic Regression(BLR)model identified key aspects influencing hub status,with the assistance of an Exploratory Factor Analysis(EFA)that grouped the variables into factors.The binary‘hub’variable was defined by the main carrier’s activity and the Global Airport Connectivity Index(GACI).The factor with the highest coefficient primarily involved internal variables and,to a lesser extent,global attractiveness and population.The factor with the lowest coefficient related to the region economy.The BLR correctly identified hub status in 93.3%of cases,with 68.3%accuracy for hub airports.Airports not correctly identified by the model mostly present a lack or underutilization of existing infrastructure.展开更多
Network virtualization(NV) is pushed forward by its proponents as a crucial attribute of next generation network, aiming at overcoming the gradual ossification of current networks, particularly to the worldwide Intern...Network virtualization(NV) is pushed forward by its proponents as a crucial attribute of next generation network, aiming at overcoming the gradual ossification of current networks, particularly to the worldwide Internet. Through virtualization, multiple customized virtual networks(VNs), requested by users, are allowed to coexist on the underlying substrate networks(SNs). In addition, the virtualization scheme contributes to sharing underlying physical resources simultaneously and seamlessly. However, multiple technical issues still stand in the way of NV successful implementation. One key technical issue is virtual network embedding(VNE), known as the resource allocation problem for NV. This paper conducts a survey of embedding algorithms for VNE problem. At first, the NV business model for VNE problem is presented. Then, the latest VNE problem description is presented. Main performance metrics for evaluating embedding algorithms are also involved. Afterwards, existing VNE algorithms are detailed, according to the novel proposed category approach. Next, key future research aspects of embedding algorithms are listed out. Finally, the paper is briefly concluded.展开更多
基金funded through the programmatic funding-UIDP/04427/2020the research grant UI/BD/153356/2022 awarded by the Fundação para a Ciência e a Tecnologia(FCT)of Portugal to the Research Centre for Territory,Transports and Environment(CITTA).
文摘This paper provides a tool to identify key aspects for an airport to achieve global hub status for a given airline and determines whether these factors are related to the facility’s infrastructure,its region,or both.Despite the frequent use of the term‘hub’,there is little academic consensus on its exact definition in air transport.Many define a hub based on passenger numbers rather than the concentration of flights and passengers from the main carrier.This study addresses this gap by analyzing the factors influencing the definition of a hub and the commonalities among global hubs.Data from 300 major airports,including internal variables(runways,terminals,gates and area)and external variables(economy,population,attractiveness),were collected.A Binary Logistic Regression(BLR)model identified key aspects influencing hub status,with the assistance of an Exploratory Factor Analysis(EFA)that grouped the variables into factors.The binary‘hub’variable was defined by the main carrier’s activity and the Global Airport Connectivity Index(GACI).The factor with the highest coefficient primarily involved internal variables and,to a lesser extent,global attractiveness and population.The factor with the lowest coefficient related to the region economy.The BLR correctly identified hub status in 93.3%of cases,with 68.3%accuracy for hub airports.Airports not correctly identified by the model mostly present a lack or underutilization of existing infrastructure.
基金supported by the National Key Research and Development of China under Grant 2018YFC1314903the National Natural Science Foundation of China under Grant 61372124 and Grant 61427801
文摘Network virtualization(NV) is pushed forward by its proponents as a crucial attribute of next generation network, aiming at overcoming the gradual ossification of current networks, particularly to the worldwide Internet. Through virtualization, multiple customized virtual networks(VNs), requested by users, are allowed to coexist on the underlying substrate networks(SNs). In addition, the virtualization scheme contributes to sharing underlying physical resources simultaneously and seamlessly. However, multiple technical issues still stand in the way of NV successful implementation. One key technical issue is virtual network embedding(VNE), known as the resource allocation problem for NV. This paper conducts a survey of embedding algorithms for VNE problem. At first, the NV business model for VNE problem is presented. Then, the latest VNE problem description is presented. Main performance metrics for evaluating embedding algorithms are also involved. Afterwards, existing VNE algorithms are detailed, according to the novel proposed category approach. Next, key future research aspects of embedding algorithms are listed out. Finally, the paper is briefly concluded.
