Decomposition models with integer variables usually decompose into a master problem that comprises all the integer variables and subproblems, which evaluate the remaining variables. Subproblems with integer variables introduce additional difficulties and require the use of nonlinear duality theory. In this paper we address the solution of a mixed integer hydrothermal coordination problem combin...

The Shift Design Problem is an important optimization problem which arises when scheduling personnel in industries that require continuous operation. Based on the forecast, required staffing levels for a set of time periods, a set of shift types that best covers the demand must be determined. A shift type is a consecutive sequence of time periods that adheres to legal and union rules and can be...

The economic lot and delivery scheduling problem for a multi-stage supply chain comprising multiple items is studied in this paper. It is required to develop a synchronized replenishment strategy, and specify the sequence of production and the replenishment cycle time that achieves synchronization through the supply chain at minimum cost. The problem is presented in a novel formulation based on...

We study an integrated inventory-location problem with service requirements faced by an aerospace company in designing its service parts logistics network. Customer demand is Poisson distributed and the service levels are time-based leading to highly non-linear, stochastic service constraints and a nonlinear, mixed-integer optimization problem. Unlike previous work in the literature, which prop...

Benders’ decomposition is a popular mathematical and constraint programming algorithm that widely applied to exploit problem structure arising from real-world applications. While useful for exploiting in programs, the use of typically requires significant implementation effort achieve an effective solution algorithm. Traditionally, has been viewed as specific algorithm, which limited developmen...

Abstract This paper describes a maintenance scheduling model for digester banks. Digester banks are network-connected assets that lie on the critical path of Bayer process, chemical refinement process converts bauxite ore into alumina. The require different activities at due times. Furthermore, schedule is subject to production-related constraints and resource limitations. Given complexity larg...

Environmental, social and economic concerns motivate the operation of closed-loop supply chain networks (CLSCN) in many industries. We propose a novel profit maximization model for CLSCN design as a mixedinteger linear program inwhich there is flexibility in covering the proportions of demand satisfied and returns collected based on the firm’s policies. Our major contribution is to develop a no...

We consider a generalized version of the rooted connected facility location problem which occurs in planning of telecommunication networks with both survivability and hop-length constraints. Given a set of client nodes, a set of potential facility nodes including one predetermined root facility, a set of optional Steiner nodes, and the set of the potential connections among these nodes, that ta...

We study the strip packing problem, in which a set of two-dimensional rectangular items has to be packed in a rectangular strip of fixed width and infinite height, with the aim of minimizing the height used. The problem is important because it models a large number of real-world applications, including cutting operations where stocks of materials such as paper or wood come in large rolls and ha...

Walter Rei, Michel Gendreau Département d’informatique et de recherche opérationnelle and Centre de recherche sur les transports, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Canada, H3C 3J7, {[email protected], [email protected]} Jean-François Cordeau, Patrick Soriano HEC and Centre de recherche sur les transports, Montréal, 3000 chemin de la Côte-Sainte-C...