S. Ilker Birbil

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This paper proposes a new heuristic for global optimization. The method utilizes an attraction-repulsion mechanism to move the sample points towards the optimality. The proposed scheme can be used either as a stand-alone approach or as an accompanying procedure for other methods. Some test results on nonlinear test functions in the category of “minor to(More)
We consider a class of stochastic mathematical programs with complementarity constraints, in which both the objective and the constraints involve limit functions or expectations that need to be estimated or approximated. Such programs can be used for modeling “average” or steady-state behavior of complex stochastic systems. Recently, simulation-based(More)
This paper discusses an approach to solve the joint replenishment problem in a production environment with variable production cost. These variable production costs occur due to economies of scale in production. Under this environment, the model leads to a global optimization problem, which is investigated by using some standard results from convex(More)
Abstract: In this paper, we develop a simultaneous column-and-row generation algorithm that could be applied to a general class of large-scale linear programming problems. These problems typically arise in the context of linear programming formulations with exponentially many variables. The defining property for these formulations is a set of linking(More)
Ş. İlker Birbil Faculty of Engineering and Natural Sciences, Sabancı University, 34956 Istanbul, Turkey, sibirbil@sabanciuniv.edu, http://people.sabanciuniv.edu/sibirbil J.B.G. Frenk Erasmus University Rotterdam, Postbus 1738, 3000 DR Rotterdam, The Netherlands, frenk@few.eur.nl, http://people.few.eur.nl/frenk/ Joaquim A.S. Gromicho Vrije Universiteit,(More)
Airline revenue management is about identifying the maximum revenue seat allocation policies. Since a major loss in revenue results from cancellations and no-show passengers, over the years overbooking has received a significant attention in the literature. In this study, we propose new models for static and dynamic single-leg overbooking problems. In the(More)
An alternative smoothing method for the high dimensional max function has been studied. The proposed method is a recursive extension of the two dimensional smoothing functions. In order to analyze the proposed method, a theoretical framework related to smoothing methods has been discussed. Moreover, we support our discussion by considering some application(More)
In this note we give an elementary proof of the Fritz-John and Karush–Kuhn–Tucker conditions for nonlinear finite dimensional programming problems with equality and/or inequality constraints. The proof avoids the implicit function theorem usually applied when dealing with equality constraints and uses a generalization of Farkas lemma and the(More)
A: This paper discusses a modeling approach to robust crew pairing when a set of extra flights is likely to be added to the regular flight schedule. The set of these possible extra flights is known at the planning stage. We demonstrate that these extra flights may be incorporated into the schedule if necessary by modifying the planned crew pairings(More)