This paper presents an Optimised Search Heuristic that combines a tabu search method with the verification of violated valid inequalities. The solution delivered by the tabu search is partially destroyed by a randomised greedy procedure, and then the valid inequalities are used to guide the...

The set covering problem is an NP-hard combinatorial optimization problem that arises in applications ranging from crew scheduling in airlines to driver scheduling in public mass transport. In this paper we analyze search space characteristics of a widely used set of benchmark instances through...

PRECON S.A is a manufacturing company dedicated to produce prefabricated concrete parts to several industries as rail transportation and agricultural industries.Recently, PRECON signed a contract with RENFE, the Spanish National Rail Transportation Company to manufacture pre-stressed concrete...