Kerem Akartunali

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Multi-level production planning problems in which multiple items compete for the same resources frequently occur in practice, yet remain daunting in their difficulty to solve. In this paper we propose a heuristic framework that can generate high quality feasible solutions quickly for various kinds of lot-sizing problems. In addition, unlike many other(More)
Lot-Sizing Problems Kerem Akartunalı Dept. of Management Science, University of Strathclyde, Glasgow, G1 1QE, UK, kerem.akartunali@strath.ac.uk Ioannis Fragkos Management Science & Innovation, University College London, London WC1E 6BT, UK, i.fragkos@ucl.ac.uk Andrew J. Miller Advanced Analytics Manager, UPS, 30328 Atlanta, GA, USA,(More)
An Optimization Framework for Solving Capacitated Multi-level Lot-sizing Problems with Backlogging Tao Wu†, Leyuan Shi†,>, Joseph Geunes‡, Kerem Akartunalı∗ † Department of Industrial and Systems Engineering, University of Wisconsin-Madison, Madison, WI 53706 ‡ Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL 32611 ∗(More)
In this paper, we propose a simple but efficient heuristic that combines construction and improvement heuristic ideas to solve multi-level lot-sizing problems. A relax-and-fix heuristic is firstly used to build an initial solution, and this is further improved by applying a fix-and-optimize heuristic. We also introduce a novel way to define the(More)
Simultaneous Fluence Weight and Aperture Optimization in VMAT, Tomotherapy, and CyberKnife Kerem Akartunalı Department of Management Science, University of Strathclyde, Glasgow, G1 1QE, United Kingdom, kerem.akartunali@strath.ac.uk Vicky Mak-Hau School of Information Technology, Deakin University, Burwood, Vic 3125, Australia, vicky.mak@deakin.edu.au Thu(More)
This paper is the second of two papers entitled “Airline Planning Benchmark Problems”, aimed at developing benchmark data that can be used to stimulate innovation in airline planning, in particular, in flight schedule design and fleet assignment. The former has, to date, been under-represented in the optimization literature, due in part to the difficulty of(More)
Several mixed integer programming formulations have been proposed for modeling capacitated multi-level lot sizing problems with setup times. These formulations include the socalled Facility Location formulation, the Shortest Route formulation, and the Inventory and Lot Sizing formulation with (`, S) inequalities. In this paper, we demonstrate the(More)
This paper proposes a mixed integer programming formulation for modeling the capacitated multi-level lot sizing problem with both backlogging and setup carryover. Based on the model formulation, a progressive time-oriented decomposition heuristic framework is then proposed, where improvement and construction heuristics are effectively combined, therefore(More)