Information Management in a Cooperative Method for the Vehicle Routing Problem with Time Windows

As transportation problems grow larger with the new world economy, so do the problem size and complexity. To be able to produce consistent solutions, individual solving methods tends to be very complex. Also, a compromise between solution quality and computing time needs to be reached. Transportation problems such as Vehicle Routing Problem with Time Windows (VRPTW ) are very difficult to solve by their combinatorial nature. Parallelism has become more accessible in the past few years and new methods like Cooperative Search are emerging and have proven to be very competitive in rapidly attaining consistent results with little programming overhead. In recent work [3] [4] [2] [5], cooperative search have shown some interesting properties: increased robustness of solution quality, reduced computational time and an improved search path of the individual involved methods to provide even better results. In a particular version [7] of Cooperative Search based on a Central Memory approach, in which several search threads cooperate by asynchronously