This paper analizes a new variant of the Traveling Salesman Problem (TSP) in which nodes belong to various color classes and each color class must be visited as an entity. We show that the problem is APX-hard and provide exact solutions for special cases and a two-phase heuristic for the general...

The scheduling problem addressed in this paper concerns a manufacturer who produces a variety of product types and operates in a make-to-order environment. Each customer order consists of known quantities of the different product types, and must be delivered as a single shipment. Periodically...