Kian, RamerKargar, Kamyar2018-04-122018-04-1220160360-8352http://hdl.handle.net/11693/36863In this paper, we study the hub location problem with a power-law congestion cost and propose an exact solution approach. We formulate this problem in a conic quadratic form and use a strengthening method which rests on valid inequalities of perspective cuts in mixed integer nonlinear programming. In a numerical study, we compare two well known types of mathematical modeling in the hub-location problems which are solved with different branch and cut strategies. The strength and weakness of the formulations are summarized based on an extensive numerical study over the CAB data set. © 2016 Elsevier LtdEnglishConic quadratic programmingHub-and-spoke networksNonlinear congestion costValid inequalitiesAir transportationNonlinear programmingNumber theoryQuadratic programmingSite selectionTraffic congestionCongestion costsExact solutionHub and spoke networksHub location problemsHub-and-spoke network designMixed-integer nonlinear programmingStrengthening methodsValid inequalityInteger programmingArticle10.1016/j.cie.2016.09.019