Cooperative Procurement Problems and Benders Decomposition

In this doctoral thesis a cooperative procurement problem is addressed. The problem considers several aspects from different research streams simultaneously. Namely, elements of lot-sizing, the idea of cooperation as in problems tackled using cooperative game theory, lateral transshipments, which often occur in inventory models, and quantity discounts, which occur in lot-sizing as well as supplier selection problems are brought together. The result of this merge is the development of an integrated problem definition that considers interdependencies between purchasing decisions, quantity discounts, lateral transshipments and inventory holding costs interpreted as cost of capital in order to make smart, cost-effective purchasing decisions for all members of a purchasing alliance. A major contribution of this work is the development of techniques to accelerate classic Benders decomposition, the favoured solution approach. Various acceleration techniques are presented, compared and tested. Thorough numerical studies show the perfomances of the different approaches and examine their competitiveness in comparison to commercial software.