Lars Magnus Hvattum

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This paper addresses the robust vehicle routing problem with time windows. We are motivated by a problem that arises in maritime transportation where delays are frequent and should be taken into account. Our model only allows routes that are feasible for all values of the travel times in a predetermined uncertainty polytope, which yields a robust(More)
This paper studies the vehicle routing problem with time windows where travel times are uncertain and belong to a predetermined polytope. The objective of the problem is to find a set of routes that services all nodes of the graph and that are feasible for all values of the travel times in the uncertainty polytope. The problem is motivated by maritime(More)
• In the Stochastic Inventory Routing Problem (SIRP) – a supplier controls the inventories of the customers – the supplier decides who, when and how much to deliver – the demand of each customer is stochastic, so stock-outs may be unavoidable – given which customers to service on a day, and how much to deliver, the remaining problem is a Vehicle Routing(More)
This paper focuses on a subclass of box-constrained, non-linear optimization problems. We are particularly concerned with settings where gradient information is unreliable, or too costly to calculate, and the function evaluations themselves are very costly. This encourages the use of derivative free optimization methods, and especially a subclass of these(More)