A Tabu Search Algorithm for the Traveling Purchaser Problem with Transportation Time Limit

This study extends the well-known traveling purchaser problem (TPP) by considering a transportation time limit of perishable food in cold-chain logistics. The problem is called the traveling purchaser problem with transportation time limit (TPP-TTL). The objective of the TPP-TTL is to find a route and procurement plan for the purchaser to satisfy the demand of a number of product types with minimum cost. To satisfy the product demand, the purchaser visits a number of capacitated markets, in which the available amount of products is limited. Furthermore, since the travel times cause deterioration on the perishable products, a transportation time limit is taken into account in the TPP-TTL for each product type. The problem is formulated as a mixed-integer programming model and solved by using a tabu search (TS) algorithm. In the computational experiments, TS is carried out for a number of different-sized instances and the results are compared to the results obtained by GUROBI solver to determine the performance of the proposed algorithm. The results of the experiments show that the TS is capable to find many optimal results with less computational time than the GUROBI solver.