110,484 research outputs found

    Hub location under competition

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    Ankara : The Department of Industrial Engineering and the Graduate School of Engineering and Science of Bilkent University, 2013.Thesis (Master's) -- Bilkent University, 2013.Includes bibliographical references leaves 64-69.Hubs are consolidation and dissemination points in many-to-many flow networks. The hub location problem is to locate hubs among available nodes and allocate non-hub nodes to these hubs. The mainstream hub location studies focus on optimal decisions of one decision-maker with respect to some objective(s) even though the markets that benefit hubbing are oligopolies. Therefore, in this thesis, we propose a competitive hub location problem where the market is assumed to be a duopoly. Two decision-makers (or firms) sequentially decide the locations of their hubs and then customers choose the firm according to provided service levels. Each decision-maker aims to maximize his/her market share. Having investigated the existing studies in the field of economy, retail location and operation research, we propose two problems for the leader (former decision-maker) and follower (latter decision-maker): (r|Xp) hub-medianoid and (r|p) hub-centroid problems. After defining them as combinatorial optimization problems, the problems are proved to be NP-hard. Linear programming models are presented for these problems as well as exact solution algorithms for the (r|p) hub-centroid problem that outperform the linear model in terms of memory requirement and CPU time. The performance of models and algorithms are tested by the computational analysis conducted on two well-known data sets from the hub location literature.Mahmutoğulları, Ali İrfanM.S

    Hub location under competition

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    Hubs are consolidation and dissemination points in many-to-many flow networks. Hub location problem is to locate hubs among available nodes and allocate non-hub nodes to these hubs. The mainstream hub location studies focus on optimal decisions of one decision-maker with respect to some objective(s) even though the markets that benefit hubbing are oligopolies. Therefore, in this paper, we propose a competitive hub location problem where the market is assumed to be a duopoly. Two decision-makers (or firms) sequentially decide locations of their hubs and then customers choose one firm with respect to provided service levels. Each decision-maker aims to maximize his/her own market share. We propose two problems for the leader (former decision-maker) and follower (latter decision-maker): (r|Xp)hub-medianoid and (r|p)hub-centroid problems, respectively. Both problems are proven to be NP-complete. Linear programming models are presented for these problems as well as exact solution algorithms for the (r|p)hub-centroid problem. The performance of models and algorithms are tested by computational analysis conducted on CAB and TR data sets. © 2015 Elsevier B.V. and Association of European Operational Research Societies (EURO) within the International Federation of Operational Research Societies (IFORS). All rights reserved

    The governance of Singapore’s knowledge clusters: off shore marine business and waterhub

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    Based on two case studies of knowledge clusters (off shore marine/rig business and water hub) in Singapore, the paper illustrates the importance of good knowledge governance in creating robust and value-creating knowledge clusters. We begin by defining key terms used such as knowledge clusters, hubs and governance, followed by a short historical account of good knowledge governance for Singapore’s development. The two cases studies of knowledge clusters presented here include (i) the offshore oil rig business (Keppel) which we posit as an example of innovative value creation based on sophisticated fabrication methods and R&D as well as (ii) the island republic’s dynamic and rapidly emerging, global hydrohub called ‘WaterHub’. We examine the structural characteristics of both clusters, assess their progress based on the cluster lifecycle literature, highlight key governance enablers required to create and sustain such competitive hubs and draw conclusions for K4D latecomers

    Regional Hub Port Development - The Case of Montevideo, Uruguay

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    This paper reflects on port development in Uruguay in an environment of trilateral interport competition. The regional characteristics of port development in terms of their geographical, functional and operational characteristics are discussed by analysing the port system’s evolution. The case of Montevideo as the success or failure of a regional hub port development strategy is analysed in detail. Particular attention is given to the evolution and impact of the liner shipping service network in defining the role of a port within a regional port system. Further, the evolution of the port of Montevideo in terms of institutional and organisational and the related strategy are described, with focus on the effect on transhipment cargo in the port. The main findings are twofold. First, port development in Montevideo been driven proactively and under a clear strategy, but still faces a number of challenges. Second, economies of scale in transport, port infrastructure and connectivity are important determinants of port development, of which the latter is principally driven by external actors, the shipping lines. The paper shows that despite strong efforts Uruguay and its principal port Montevideo are highly dependent on external factors, particularly the level of connectivity, in their strategy to develop Montevideo as a regional hub. Thus the findings are relevant in relation to the discussion of Montevideo’s development potentials as a hub on South America’s East Coast in particular and the effects of external influences on port development from in general.Regional port development; transhipment, connectivity; distance; Latin America

    Testing the Home Market Effects in a Multi-country World: The Theory

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    We extend the two-country model by Krugman (1980) to a multi-country set-up and show that the `home-market effect' highlighted with two countries does not readily extend to such a more general setting. In particular, we prove that the most important result, namely the disproportionate causation from demand to supply, generalizes only under the fairly implausible assumption of pairwise symmetric trade costs between all countries. We argue, therefore, that the implications of product differentiation for the structure of world trade are better characterized in terms of spatial (`accessibility') and non-spatial (`attraction') effects, and we provide a theory-based specification that suggests how to test the home market effect in a more general settinghome market effect; hub effect; market potential; new trade theory; economic geography

    The determinants of airport hub locations, service, and competition

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    Although the airline industry has been studied extensively since passage of the Airline Deregulation Act of 1978, relatively little effort has gone into examining how hub location affects the level of service and degree of competition found at airports in the system. To help close this gap, we investigate the geographic distribution of airline hub operations, the level of service, and the extent of competition at 112 major U.S. airports, extending previous work by Bauer (1987) and Butler and Huston (1989). Our key innovation is that we derive our measures of service and competition from indicator matrices that describe each airline's route system.Airlines

    Hub and Spoke Trade Agreements under Oligopoly with Asymmetric Costs

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    Using an oligopoly model of trade with asymmetric costs, we study the individual and world welfare implications of a hub and spoke trade agreement where the hub country is more efficient than spoke countries. Under a hub and spoke trade regime, the hub country can benefit at the expense of the spokes relative to free trade. Furthermore, if the hub is sufficiently efficient compared to the spokes, such a regime can yield higher global welfare than free trade. Preferential treatment of the efficient hub country in its export markets improves world welfare because it helps allocate a larger share of the world's output to a low cost location.oligopoly, hub and spoke trade agreements, global free trade

    Financial locations : Frankfurt’s place and perspectives

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    The introduction of a common currency as well as the harmonization of rules and regulations in Europe has significantly reduced distance in all its guises. With reduced costs of overcoming space, this emphasizes centripetal forces and it should foster consolidation of financial activity. In a national context, as a rule, this led to the emergence of one financial center. Hence, Europeanization of financial and monetary affairs could foretell the relegation of some European financial hubs such as Frankfurt and Paris to third-rank status. Frankfurt’s financial history is interesting insofar as it has lost (in the 1870s) and regained (mainly in the 1980s) its preeminent place in the German context. Because Europe is still characterized by local pockets of information-sensitive assets as well as a demand for variety the national analogy probably does not hold. There is room in Europe for a number of financial hubs of an international dimension, including Frankfurt

    Dynamics in the European Air Transport Network, 2003-9 : an explanatory framework drawing on stochastic actor-based modeling

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    In this paper, we outline and test an explanatory framework drawing on stochastic actor-based modeling to understand changes in the outline of European air transport networks between 2003 and 2009. Stochastic actor-based models show their capabilities to estimate and test the effect of exogenous and endogenous drivers on network changes in this application to the air transport network. Our results reveal that endogenous structural effects, such as transitivity triads, indirect relations and betweenness effects impact the development of the European air transport network in the period under investigation. In addition, exogenous nodal and dyadic covariates also play a role, with above all the enlargement of the European Common Aviation Area having benefitted its new members to open more air routes between them. The emergence of major low-cost airline-focused airports also significantly contributed to these changes. We conclude by outlining some avenues for further research
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