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T his article considers the overall crew management problem arising from the daily operation of an urban transit bus company that serves the metropolitan area of the city of Belo Horizonte, Brazil. Due to its intrinsic complexity, the problem is divided in two distinct subproblems: crew scheduling and crew rostering. We have investigated each of these(More)
We consider several strategies for computing optimal solutions to large scale crew scheduling problems. Provably optimal solutions for very large real instances of such problems were computed using a hybrid approach that integrates mathematical and constraint programming techniques. The declarative nature of the latter proved instrumental when modeling(More)
The contents of this report are the sole responsibility of the authors. O conteúdo do presente relatório é de única responsabilidade dos autores. Abstract. We present a new method that addresses the various deficiencies of the state-of-the-art non-linear invariant generation methods for hybrid systems. Present approaches for non-linear invariant generation(More)
In this article, we present a hybrid methodology for the exact solution of large scale real world crew scheduling problems. Our approach integrates mathematical programming and constraint satisfaction techniques, taking advantage of their particular abilities in modeling and solving specific parts of the problem. An Integer Programming framework was(More)
Brazilian petrobras is one of the world largest oil companies. Recurrently, it faces a very difficult planning and scheduling problem: how to operate a large pipeline network in order to adequately transport oil derivatives and biofuels from refineries to local markets. In spite of being more economical and environmentally safer, the use of a complex(More)
The contents of this report are the sole responsibility of the authors. O conteúdo do presente relatório é de única responsabilidade dos autores. Abstract We describe new decidability results that respond completely to major conjectures on termination analysis of linear loop programs, on all initial values interpreted over the reals. To the best of our(More)