Hub Status Research Articles

What is the busiest time at an airport? Clustering U.S. hub airports based on passenger movements

Accurate clustering of airports enables airport authorities and operators to precisely position themselves in the competitive market, facilitates airlines to efficiently allocate resources, and empowers the research community with credible data for new discoveries. Existing clustering studies largely use traffic volume, network connectivity, or operational efficiency to group airports into hierarchical clusters or parallel partitions. Developing a different perspective, this study focuses upon a key bottleneck of outbound passenger movements in airport terminals, the security checkpoints, and uses the Transportation Security Administration (TSA) Customer Throughput/Wait Times Reports to cluster hub airports of the United States. With the input data structured as univariate time-series, k-shape, a clustering algorithm that is robust to time axis distortion and computationally efficient, is selected to analyze the similarity of time-series using shape-based distance. The clustering results are validated by examining the raw and z-normalized data of selected airport clusters on six sampled dates. Analysis results indicate that k-shape is competent and efficient to process and cluster time-series data used for this specific research. This study offers a fresh perspective to cluster commercial airports using an infrequently employed dataset. The clustering results reveal how the geographical location, hub status in airlines' operational network, and destination type of an airport affect the movement of outbound passengers through terminals

Senior therapeutic community members show greater consistency when affirming peers: evidence of social learning

PurposeTherapeutic communities (TCs) use social learning between peers in treating substance abuse. One mechanism for fostering social learning is peer affirmations for prosocial behavior. The purpose of this study is to use consistency of affirmations as a test of whether social learning does occur.Design/methodology/approachUsing the results of a social network survey of 50 women in a corrections-based TC, the authors compared affirmations and nonprogrammatic compliments exchanged between residents as two directed social networks. The authors evaluated consistency of judgment using the hubs and authorities algorithm, and tested to see whether more senior residents are more likely to be hubs, thereby showing more consistent judgment.FindingsMore senior residents show greater consistency with peers in program affirmations but not in nonprogrammatic compliments. Hub status in the network of affirmations increases most rapidly in the first 200 days of residence, with slower increases thereafter.Research limitations/implicationsThis study is limited to one survey of the women in one TC. The external validity of the findings is therefore unclear. The results suggest that social learning of TC principles and prosocial behavior does occur and that it is not simply a function of popularity among peers. This seems to happen most rapidly in the first 200 days, suggesting that programs much shorter than six months may limit this process.Originality/valueThis is the first use of the hubs and authorities algorithm with a social network drawn from a therapeutic community and the first attempt to verify social learning through a social network analysis.

Simulation-based assessment methodology to improve ground service operations at a hub airport

ABSTRACT Airport terminals are dynamic environments and security/passport services generally constitute costly bottlenecks in terminals. Increases in the number of airline passengers compels airport terminals to provide more efficient services to its customers under space and resource limitations. This study examines the level of service of passenger processes at Istanbul Atatürk Airport by constructing a comprehensive simulation model. It focuses mainly on passport control services and passenger transfer security services because of the airport's hub status and the strategy of Turkish Airlines. The increasing number of transfer passengers may cause disruptions in departure flight schedules due to slow passenger processes. After validating the model, we investigate the consequences of three main alternative solutions, including 17 sub-scenarios, to capture target quality levels. Finally, we provide the results for each scenario to investigate the optimum allocation of resources to terminal operations.

Complex network analysis of MCI-AD EEG signals under cognitive and resting state

ObjectiveThe purpose of this study is to characterize functional connectivity changes in mild cognitive impaired Alzheimer’s disease (MCI-AD) under resting and cognitive task conditions. MethodEEG signals were recorded under resting states (Eyes closed (EC) and Eyes open (EO)) and cognitive states (Mental Arithmetic Eyes closed (MAEC) and Mental Arithmetic Eyes open (MAEO)) conditions. Functional connectivity metrics were calculated using weighted phase lag index (WPLI). Topological features of the functional connectivity network were analyzed through minimum spanning tree (MST) algorithm. Betweenness centrality was estimated in five different regions of the brain to study hub importance. ResultsAn increase in values of eccentricity and diameter were observed in patient group in five frequency bands of delta, theta, alpha1, alpha 2 and beta bands under resting and cognitive states. A reduction in leaf fraction was observed in alpha 1 band of EO condition. The results indicated a reduction in functional integration in the brain network of MCI-AD patients. Analysis of MST parameters revealed a higher disintegrated network for the alpha band under EO protocol. The study of hub status in the network displayed an elevated hub status in the central region for the patient group under cognitive task. The study also observed increased integration in gamma band in MCI – AD subjects than healthy controls under cognitive load. ConclusionDisintegration of functional network in alpha band under eyes open protocol and elevated hub strength in central region during cognitive task could be distinguishing features that could aid early detection of AD.

Protein Subdomain Enrichment of NUP155 Variants Identify a Novel Predicted Pathogenic Hotspot.

Functional variants in nuclear envelope genes are implicated as underlying causes of cardiopathology. To examine the potential association of single nucleotide variants of nucleoporin genes with cardiac disease, we employed a prognostic scoring approach to investigate variants of NUP155, a nucleoporin gene clinically linked with atrial fibrillation. Here we implemented bioinformatic profiling and predictive scoring, based on the gnomAD, National Heart Lung and Blood Institute-Exome Sequencing Project (NHLBI-ESP) Exome Variant Server, and dbNSFP databases to identify rare single nucleotide variants (SNVs) of NUP155 potentially associated with cardiopathology. This predictive scoring revealed 24 SNVs of NUP155 as potentially cardiopathogenic variants located primarily in the N-terminal crescent-shaped domain of NUP155. In addition, a predicted NUP155 R672G variant prioritized in our study was mapped to a region within the alpha helical stack of the crescent domain of NUP155. Bioinformatic analysis of inferred protein-protein interactions of NUP155 revealed over representation of top functions related to molecular transport, RNA trafficking, and RNA post-transcriptional modification. Topology analysis revealed prioritized hubs critical for maintaining network integrity and informational flow that included FN1, SIRT7, and CUL7 with nodal enrichment of RNA helicases in the topmost enriched subnetwork. Furthermore, integration of the top 5 subnetworks to capture network topology of an expanded framework revealed that FN1 maintained its hub status, with elevation of EED, CUL3, and EFTUD2. This is the first study to report novel discovery of a NUP155 subdomain hotspot that enriches for allelic variants of NUP155 predicted to be clinically damaging, and supports a role for RNA metabolism in cardiac disease and development.

Abiotic determinants of airport performance: Insights from a global survey

This paper explores airport business in association with its operational, economic, geographical and regulatory environment. The two-stages methodology engages a post-positivist approach and data triangulation. In the first stage, airport performance (AP) is measured with the tailor-made Airport Business Excellence Model in 137 airports spread over 90 countries. Subsequently, the AP scores are examined vis-à-vis an extensive set of abiotic/externally determined factors, such as ownership, regulation, size, seasonality, hub status, location, economic development, traffic mix and performance management system. The data is first processed with the Kruskall-Wallis non-parametric test to detect statistical differences in AP levels among airport subgroups and the relevant contribution of the abiotic determinants is then investigated by multiple regression analysis. The results indicate that the effectiveness of the regulatory mix is in close connection with second-order charging schemes. Furthermore, low seasonality and an extra-large airport size are positively related to AP, whereas non-hub status, the absence of formal performance management systems and the blending of public and private sectors in mixed ownership/management schemes act in the opposite direction.

Salient or Not? The U.S. Air Travel Taxes

We exploit the abundance of tax changes in the airline industry after the DOT's full-disclosure rule. We determine the effective tax rate and analyze how passengers reacted to the tax changes. Hausman-type instruments are used to address the problems arising from endogenously determined prices. We show that passengers react more strongly to taxes than to price changes. In addition, this response is stronger if the airport (of origin) is close to a nearby airport with more connections available. This over-optimization parameter decreases as the passenger level increases. Significant differentials in the parameter are found for different carrier types. Hub status also appears to be a factor in shaping salience, particularly at the origin airport. Neither market structures nor competition seem to generate significant differentials. We extend the literature by examining the salience of air travel taxes and providing potential explanations for sources of over-optimization.

Impact of high-speed rail network development on airport traffic and traffic distribution: Evidence from China and Japan

We explore the impacts of high-speed rail (HSR) development on airport-level traffic by considering not only the availability of air-HSR intermodal linkage between the airport and HSR station but also the position of the airport’s city in the HSR network. The latter is measured by both the degree centrality (to reflect connectivity) and the harmonic centrality (to reflect accessibility). Using a sample of 46 airports in China and a sample of 16 airports in Japan over the period of 2007–2015, we conduct regression analysis and compare the effects of HSR network development on airports in these two Northeast Asian countries. We find that as HSR connectivity or accessibility increases, there is, on average, a decline in airports’ domestic and total traffic in China but little change in Japan. Meanwhile, we observe a strong complementary effect of HSR to feed international flights with the presence of air-HSR intermodal linkage. As a result, some airports may experience a total traffic increase. In China, hub airports tend to gain traffic regardless the availability of air-HSR linkage, while non-hub airports are likely to lose. In Japan, on the other hand, airports with air-HSR linkage tend to gain traffic regardless the hub status. Our analysis also reveals some differentiated impacts of HSR connectivity and accessibility in China. An important policy implication is that the investment in air-HSR intermodal linkage at busy airports may not help with realizing the benefit of congestion mitigation and emission reduction. Rather, policy makers may invest air-HSR linkage at regional airports which have the potential to be converted into international gateway hubs.

Assessment of competitive hub status of cities in Europe and Asia from an international air traffic perspective

The objective of this paper is to develop a refined gravity model for the quantitative assessment of competitive hub status of cities between 2000 and 2012 from the perspective of international air traffic movements. Its focus of attention is Europe and Asia, where cross border competition has been witnessed among major cities for the role as a key international air traffic hub. To this end, the research incorporates global network connectivity (GNC) as a measure of business connections into an established gravity model that previously relied on GDP per head, population and distance to account for international air links. The results confirm the dynamic change of the air transport city hierarchy, demonstrating a stronger presence of a number of previously secondly ranked cities as international air traffic hubs over this period. The paper concludes with suggestions that possible extension of geographical scope and incorporation of domestic air traffic could enrich the insight of this approach.

Cortical covariance networks in ageing: Cross-sectional data from the Irish Longitudinal Study on Ageing (TILDA)

Ageing is associated with widespread alterations to the brain's anatomy and to attendant cortical networks. Yet, few studies to date have indexed anatomical covariance network differences within the age distribution of older adulthood, despite known phenotypic variation. Here, we explored cortical anatomical covariance networks in middle and older age cross-sectionally, using a large sample of community-dwelling older adults from the Irish Longitudinal Study on Ageing (TILDA). We assayed age-related anatomical changes via cortical thickness. Moreover, we explored age-related alterations in small-world and global properties of cortical thickness covariance networks, by targeting analyses towards the elder (ages 75–88; n = 88) and younger (ages 52–64; n = 95) sample members. Age, sex, and chronic disease-adjusted vertex-wise analyses revealed robust reductions in cortical thickness with age. Graph theoretical analyses of cortical thickness covariance networks revealed significantly lower betweenness centrality (i.e., network hub status) at left inferior parietal cortex in the eldest participant group as compared to the youngest. Furthermore, indices of small-worldness revealed greater lambda (i.e., less effective integration) across the right hemisphere of the eldest participant group versus the youngest. Our results are interpreted in the context of mechanisms of cortical atrophy in ageing, functional network organisation, and cognition in ageing.

Liner shipping alliances and their impact on shipping connectivity in Southeast Asia

Purpose The liner shipping industry underwent a major round of change between 2014 and 2017 where the concentration ratio of the top ten carriers rose from 64 per cent in 2013 to 82 per cent by 2017. This paper aims to analyze the impact of these developments on the state of shipping connectivity for major container transshipment hubs in Southeast Asia, namely, Port Klang, Singapore and Tanjung Pelepas. Design/methodology/approach The developments in shipping services deployed before and after the latest round of reshuffling in the liner shipping industry were analyzed. Findings Significant service rationalization took place in the period that saw 38 per cent reduction in the number of shipping services called at the ports. Participation in alliance arrangement was revealed to be important for shipping lines to compete successfully on the Asia–Europe trade route in the new shipping landscape. Terminal operators should expect further rationalization of services should overcapacity persist. Maintaining hub status would require the ability to accommodate the strategic, operational and commercial requirements of the entire alliance rather than just focusing on the key shipping line. Originality/value This is the first paper to examine the effects of the latest round of consolidation in the liner shipping industry. In-depth analyses were conducted for shipping services where the service configuration was examined. The case of Southeast Asia and the Asia–Europe trade route was used to illustrate the impact with managerial and policy implications for shipping lines, terminal operators and port authorities.

Integrating a large-scale interprofessional student program to address patients with complex needs

Abstract Over the last year a combined student and faculty team implemented a large-scale, interprofessional education curriculum, the Interprofessional Student Hotspotting Learning Collaborative (ISHLC).1 The ISHLC is a program initially developed and disseminated by the Camden Coalition of Healthcare Providers (CCHP), for which Thomas Jefferson University (TJU) was recently awarded National Student Hotspotting Hub status through the CCHP. The TJU development team collaborated with key stakeholders across both clinical and academic pillars to create institutional buy-in and to integrate this program into pre-existing curricula within multiple TJU health professions colleges. After a successful planning and integration phase, ISHLC launched in the fall of 2017 with eight interprofessional student teams comprised of six senior level students and two faculty members serving nine persons with complex needs through high-touch, social interventions. ISHLC participants gained experience within an interprofessional team engaging with complex patients, identifying social determinants of health, advocating to improve physical and social conditions for optimal health, and evaluating the financial and personal impacts of patient-centered interventions.

Railways and borderland spaces: The Canada–US case

Transportation has played a decisive role in transforming the economic and social geography of both the United States and Canada and in this context, railways have been prominent. Their extension in both the American and Canadian hinterlands was designed to organize territory, increase the number of settlements, support resource exploitation, and facilitate the development of regional and national markets. While geopolitical protectionism played a somewhat more prominent role in the development of railways in Canada than the United States, rail expansion in both countries was not circumscribed by the international boundary. In fact, in many cases the border actually transcended such development. In other words, the Canada–United States border has historically presented both limitations and opportunities to railway interests. This paper argues that while the basic alignment of borderland rail networks was established during the late 19th and early 20th centuries, the nodal structure, hub status, and corridor alignments of railways since the 1930s have changed drastically. It also contends that because such networks responded to changes in technologies, regional development, and market forces, they played different roles in configuring the various regions of the Canadian‐American borderlands.

Comparing passenger flow and time schedule data to analyse High-Speed Railways and urban networks in China

China’s High-Speed Railways (HSR) network is the biggest in the world, transporting large numbers of passengers by high-speed trains through urban networks. Little is known about the analytical meaning of the use of two types of flow data, namely, time schedule (transportation mode flow) and passenger flow data, to characterise the configuration of urban networks regarding the potential spatial effects of HSR networks on urban networks. In this article, we compare HSR passenger flow data with time schedule data from 2013 in China within the same analytical framework. The findings show great differences in the strength of cities and links generated using the two different types of flow data. These differences can be explained largely by the socio-economic attributes of the cities involved, such as tertiary employment, GDP per capita, the cities’ topological properties (closeness centrality) in HSR networks and institutional factors (hub status), especially for the difference in link strength. The strength of first-tier cities in China with high socio-economic performance and the HSR links connecting core cites and major cities within respective regions tends to be underestimated when using time schedule flows compared with passenger flows. When analysing the spatial structure of HSR and urban networks by means of flows, it is important for urban geographers and transportation planners to consider the meaning of the different types of data with the analytical results.

The effects of new international airports and air-freight integrator's hubs on the mobility of cities in urban hierarchies: A case study in East and Southeast Asia

This paper examines international air traffic flows from, to and within East and Southeast Asia, and in turn the hub status of cities over the years from 1982 to 2012. Its focus of attention is the effects of new international airports and integrator's hubs on the mobility of cities in a region's urban hierarchy. The results reveal that Hong Kong, Shanghai, Guangzhou, Bangkok, Kuala Lumpur and Seoul are strengthening their positions as international air traffic hubs, all of which opened a new international airport. Meanwhile, three global air-freight integrators have constructed a global or regional hub in most of these cities. In contrast, Tokyo is downgraded from a top ranked global city during the period analyzed.

The Hub Status and Transportation Network of Kribi Port

In this paper, a study on four African ports was taken out that all have the ca-pability to become a hub port that can serve the central African region. The paper sort to determine which port was most suitable and port indexing was the method that was used to evaluate these ports. The ports evaluated were the port of Kribi, the port of Bata, the port of Libreville and the port of Pointe-Noire. There were other models that were also used which included linear regression and linear programming which all contributed to providing the final results of the port with the most suitable potential to serve as a hub port and meaningful results were obtained. The final results showed that the port of Pointe-Noire was the most suitable port to serve the central African region as a hub port.

Frontier Logistics Performance in Sri Lanka - The Role Play of the Customs

Sri Lanka (SL) is expected its economic growth achievement through five hubs concept –namely, Maritime, Aviation, Commercial, Knowledge and Energy Hubs. SL even now serves as an effective hub for maritime goods transport and air-passenger transport in the southern sub-continental region, drawing on its geographical and economic advantages primarily due to the location advantage. However the county’s logistics performance plays a major role in above hub concept especially with respect to Maritime, Aviation and Commercial hubs. Therefore improving logistics performance has a significant importance in the current context. This could never be achieved without highly efficient, modernized Customs administration in the country, which performs the agency and regulatory functions of the state, at the frontiers. The study draws the literature to ascertain the role played by Customs with respect to a country’s economic growth, Logistics in particular. While the customs role as a border management organization is explicit the study also draws its attention to the knowledge about Customs functionality by the respective “stakeholders”. Further the study analyses the Revised Kyoto Convention (RKC) ,the data of The Global Competitiveness Reports of World Economic Forum, United Nations, World Customs Organization, Doing Business Reports of The World Bank And The International Finance Corporation. Depth interviews have been conducted with 3 industry/commerce personnel and 2 senior officers of Customs and Board of Investment of Sri Lanka. A solid and modern legal framework is the foundation of effective customs operations. This legal framework bench marking should be based on internationally accepted standards and best practices as set out in the RKC which provides important guidelines for the design and operation of a modern and efficient customs organization. Customs reform, modernization or re-engineering considered a priority in many countries and implementation of change management is needed especially in Sri Lanka due to rapid development expected in the means of Hub status. On the other hand to enable the users to achieve the full benefits, private sector counterparts need to be included in the process and incorporate their inputs.

Plant-parasitic nematodes: towards understanding molecular players in stress responses.

Background Plant–parasitic nematode interactions occur within a vast molecular plant immunity network. Following initial contact with the host plant roots, plant-parasitic nematodes (PPNs) activate basal immune responses. Defence priming involves the release in the apoplast of toxic molecules derived from reactive species or secondary metabolism. In turn, PPNs must overcome the poisonous and stressful environment at the plant–nematode interface. The ability of PPNs to escape this first line of plant immunity is crucial and will determine its virulence. Scope Nematodes trigger crucial regulatory cytoprotective mechanisms, including antioxidant and detoxification pathways. Knowledge of the upstream regulatory components that contribute to both of these pathways in PPNs remains elusive. In this review, we discuss how PPNs probably orchestrate cytoprotection to resist plant immune responses, postulating that it may be derived from ancient molecular mechanisms. The review focuses on two transcription factors, DAF-16 and SKN-1, which are conserved in the animal kingdom and are central regulators of cell homeostasis and immune function. Both regulate the unfolding protein response and the antioxidant and detoxification pathways. DAF-16 and SKN-1 target a broad spectrum of Caenorhabditis elegans genes coding for numerous protein families present in the secretome of PPNs. Moreover, some regulatory elements of DAF-16 and SKN-1 from C. elegans have already been identified as important genes for PPN infection. Conclusion DAF-16 and SKN-1 genes may play a pivotal role in PPNs during parasitism. In the context of their hub status and mode of regulation, we suggest alternative strategies for control of PPNs through RNAi approaches.

Identifying the epileptogenic zone in interictal resting-state MEG source-space networks.

In one third of patients, seizures remain after epilepsy surgery, meaning that improved preoperative evaluation methods are needed to identify the epileptogenic zone. A potential framework for such a method is network theory, as it can be applied to noninvasive recordings, even in the absence of epileptiform activity. Our aim was to identify the epileptogenic zone on the basis of hub status of local brain areas in interictal magnetoencephalography (MEG) networks. Preoperative eyes-closed resting-state MEG recordings were retrospectively analyzed in 22 patients with refractory epilepsy, of whom 14 were seizure-free 1 year after surgery. Beamformer-based time series were reconstructed for 90 cortical and subcortical automated anatomic labeling (AAL) regions of interest (ROIs). Broadband functional connectivity was estimated using the phase lag index in artifact-free epochs without interictal epileptiform abnormalities. A minimum spanning tree was generated to represent the network, and the hub status of each ROI was calculated using betweenness centrality, which indicates the centrality of a node in a network. The correspondence of resection cavity to hub values was evaluated on four levels: resection cavity, lobar, hemisphere, and temporal versus extratemporal areas. Hubs were localized within the resection cavity in 8 of 14 seizure-free patients and in zero of 8 patients who were not seizure-free (57% sensitivity, 100% specificity, 73% accuracy). Hubs were localized in the lobe of resection in 9 of 14 seizure-free patients and in zero of 8 patients who were not seizure-free (64% sensitivity, 100% specificity, 77% accuracy). For the other two levels, the true negatives are unknown; hence, only sensitivity could be determined: hubs coincided with both the resection hemisphere and the resection location (temporal versus extratemporal) in 11 of 14 seizure-free patients (79% sensitivity). Identifying hubs noninvasively before surgery is a valuable approach with the potential of indicating the epileptogenic zone in patients without interictal abnormalities.

Modeling Airlines’ Decisions on City-Pair Route Selection Using Discrete Choice Models

An approach based on the discrete choice random-utility theory is presented to model airlines’ decisions of strategically adding or deleting city-pair routes. The approach consists of methods for identification of air transportation networks, determination of choice sets, and comparison and validation of developed discrete choice models. The developed approach enables the quantification and estimation of airlines’ decision-making preferences to the identified explanatory variables, including market demand, direct operating costs, distance, and whether terminal airports are hubs or not. It is observed that market demand more significantly affects the decisions on route deletion than their addition. Furthermore, the effect of direct operating costs is significant in the decision of route deletion, whereas it is not in route addition. Finally, airlines’ decisions vary, depending on the airport hub status. These trends are observed consistently over time in the current analysis of historical data from 2004 to 2013. The developed models show better prediction as compared to other models in literature. With the developed models, an air transportation network generator is constructed that, in turn, is used for model validation. This approach benefits those who want to understand airlines’ decision-making behaviors and those who need to understand the past and future evolution of an air transportation network.