Hybrid Optimization Methods for Warehouse Logistics and the Reconstruction of Destroyed Paper Documents

Themain topic of this thesis is the solving of real-world combinatorial optimization problems from two domains: storage location assignments and picking tour computations in warehouse management as well as the reconstruction of destructed paper documents from the field of forensics. Although from the application point of view these two topics have not much in common, parallels can be identified when analyzing them in more detail. All of them are extended versions of well-known combinatorial optimization problems, i.e., the storage location assignment is a variant of blocks world; whereas the tour computations as well as the reconstruction of documents are related to the traveling salesman problem. In addition, a short overview on the standard methods for solving hard combinatorial optimization problem is given which will then be adapted for the topics of this thesis. First, a variant of the storage location assignment problem is examined which typically arises among others in paper industry. Related warehouses consist of aisles orthogonal to each other and storage locations are accessed using a Last-In, First-Out policy, i.e., only the last stored item is directly accessible from each storage location. In case someone wants to access a paper roll located not immediately accessible, all paper rolls placed in front of the requested one need to be removed and (temporarily) stored in other locations. The goal of the storage location assignment examined within this thesis is to compute an assignment of paper rolls to stockyards such that during shipping minimal picking times arise which is equivalent to minimizing the number of necessary relocation operations when loading. Unfortunately, the concrete production order of the paper rolls stored within the warehouse is not known in advance due to technical constraints. Even more, the shipping dates are only estimations and may suddenly change, e.g., due to delays of the carrier. However, beside the assignment of positions within the warehouse