Section: Application Domains

Transport and logistics

Managerial problems raised by the planning of operations in transport networks, the distribution of goods, and the associated management of inventories have always been central in Operations Research. The tools of mathematical programming can bring substantial savings given the part of operation and transportation costs in the global cost of logistic. One could think that these major issues should be well resolved by now. This is simply not so. The combinatorial difficulties inherent to these problems require new techniques to increase the size of instances that can be treated. Moreover, new managerial practices and the trend of going from a hierarchical to an integrated optimization yield new problems.

Our experience in this domain includes several industrial studies:

• we are pursuing a project that simultaneously optimizes transportation routes and customer inventories (a problem known as inventory routing ) with our industrial partner Exeo Solutions [121] , [122] ;

• for Routing International, Brussels, we have combined vehicle routing and planning over a fixed time horizon [129] , [130] ;

• we are also working on variants of the traveling salesman problem (TSP): the cumulative TSP arises when the cost of an arc is inversely proportional to its position in the circuit (consider for instance a delivery man that is paid more at the beginning of the journey because of the weight he has to carry).