Mathematical programming techniques for the solution of hard combinatorial optimization problems arising in transportation

该研究计划旨在研究几类带同步约束的车辆路径问题，提出建模方法和高效的精确启发式算法。值得注意的是，我们考虑了带有换乘的车辆路径问题和多梯队的车辆路径问题。这类车辆路径问题有一个共同的特点：由于换乘点或集合点的同步，潜在的时间问题在决定给定解决方案的效率方面起着至关重要的作用。事实上，如果计时问题没有得到适当的处理，人们可能会在旅行时间方面得到一个可能更便宜的解决方案，但在总乘车时间(包括由于不正确的同步而导致的停顿时间)方面则要昂贵得多。

This research plan is intended to study several classes of vehicle routing problems with synchronization constraints, to propose modeling approaches and efficient exact and heuristic algorithms. Notably, we consider vehicle routing problems with transfers and multiple-echelon vehicle routing problems. These classes of vehicle routing problems share a common characteristic: either because of synchronization at transfer points or consolidation points, the underlying timing issue plays a crucial role in determining the efficiency of a given solution. Indeed, if the timing issue is not properly handled, one may end with a possibly cheaper solution in terms of traveling time, but much more expensive in terms of total ride time (which includes the dead times due to improper synchronization).