Giovanni Righini

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In this paper we try to describe the main characters of Heuristics \derived" from Nature, a border area between Operations Research and Arti cial Intelligence, with applications to graph optimization problems. These algorithms take inspiration from physics, biology, social sciences, and use a certain amount of repeated trials, given by one or more \agents"(More)
The vehicle routing problem with simultaneous distribution and collection (VRPSDC) is the variation of the capacitated vehicle routing problem that arises when the distribution of goods from a depot to a set of customers and the collection of waste from the customers to the depot must be performed by the same vehicles of limited capacity and the customers(More)
The resource-constrained elementary shortest path problem arises as a pricing subproblem in branch-and-price algorithms for vehicle routing problems with additional constraints. We address the optimization of the resource-constrained elementary shortest path problem and we present and compare three methods. The first method is a well-known exact dynamic(More)
The ordered open-end bin packing problem is a variant of the bin packing problem in which the items to be packed are sorted in a given order and the capacity of each bin can be exceeded by the last item packed into the bin. We present a branch-and-price algorithm for its exact optimization. The pricing subproblem is a special variant of the binary knapsack(More)