Plenary Keynote

Recent multi-objective branch and bound algorithms and an example in facility location
Anthony Przybylski and Xavier Gandibleux, Nantes Université, France

On the timeline of branch and bound algorithms, the first complete multi-objective branch and bound algorithm has been proposed by Kiziltan and Yucaoglu in 1983. And until recently, rather few multi-objective branch and bound algorithms have been proposed. This situation is not surprising as the contributions on the extensions of the components of branch and bound for multi-objective optimization are recent. For example, the concept of bound sets, which extends the classic notion of bounds, has been mentioned by Villarreal and Karwan in 1981. But it was only developed for the first time in 2001 by Ehrgott and Gandibleux, and fully defined in 2007. In this talk, we present a selection of multi-objective branch and bound, covering concepts, components and recent algorithms devoted to linear optimization problems and aiming to compute a complete set of efficient solutions. We discuss an example of multi-objective branch and bound that we have developed for the two objectives binary uncapacitated facility location problem.

Lot-sizing and Sustainability
Safia Kedad-Sidhoum, Conservatoire National des Arts et Métiers, France

The talk will focus on lot-sizing problems related to sustainability. Starting from some basic results on simple lot-sizing problems, we will illustrate some recent applications under this scope. We will show how to integrate some environmental aspects in the classical deterministic lot-sizing models and particularly how to consider carbon emissions in production and distribution planning problems. We will also consider stochastic lot-sizing models within the framework of reverse logistics where the classical economic lot-sizing problems have been extended with a remanufacturing option which allows reprocessing of used products to obtain like-new products. For the considered problems, we will propose mathematical formulations, highlight some complexity issues, structural properties, polynomial and exact algorithms and exhibit some open and promising questions.