400 Int. J. Applied Decision Sciences, Vol. 8, No. 4, 2015 Copyright © 2015 Inderscience Enterprises Ltd. A hybrid spanning tree-based genetic/simulated annealing algorithm for a closed-loop logistics network design problem Ehsan Yadegari* and Mostafa Zandieh Department of Industrial Management, Management and Accounting Faculty, Shahid Beheshti University, Tehran, Iran Email: e.yadegari@mail.sbu.ac.ir Email: ehsanyadegari@yahoo.com Email: m_zandieh@sbu.ac.ir *Corresponding author Hesamaddin Najmi Department of Industrial Engineering, University of Tehran, Tehran, Iran Email: hnajmi@ut.ac.ir Abstract: Affecting the efficiency and responsiveness of the logistics, supply chain network design, in particular, closed-loop logistics has attracted more attention in recent years. The problem in this paper is to minimise the total cost of the cyclic logistic network model by determining the best locations of plants, distribution centres (DCs), and dismantlers. Due to the NP-hard nature of the problem, it is inevitable to appeal to metaheuristic procedures to achieve satisfactory solutions for large-size problems. To tackle such an NP-hard problem, this paper proposes a simulated annealing (SA), a modified genetic algorithm (MGA), and a hybrid algorithm, applying these two algorithms based on a revised spanning tree and determinant encoding representation. To evaluate the proposed algorithms, we compare them with the genetic algorithm (GA) taken from the recent literature. Finally, it is shown that the proposed hybrid algorithm outperforms other algorithms. Keywords: closed-loop supply chain; logistics network design; spanning tree; genetic algorithm; simulated annealing algorithm. Reference to this paper should be made as follows: Yadegari, E., Zandieh, M. and Najmi, H. (2015) ‘A hybrid spanning tree-based genetic/simulated annealing algorithm for a closed-loop logistics network design problem’, Int. J. Applied Decision Sciences, Vol. 8, No. 4, pp.400–426. Biographical notes: Ehsan Yadegari is a PhD student at the Faculty of Industrial Management of Shahid Beheshti University (SBU). He received his BSc in Industrial Engineering from Iran University of Science and Technology (IUST) and MSc from Shahid Behesti University in Industrial Management majoring in operations research. His research interests are in optimisation, meta-heuristic algorithms, mathematical modelling, supply chain network