Algorithms for the multiperiod workforce scheduling and routing problem with dependent tasks

Abstract

Logistics problems lie at the core of industries' everyday operations. These types of problems are also one of the main points of interest in the Operations Research field of study. In recent decades, a class of combinatorial optimization problems, named Workforce Scheduling and Routing Problems (WSRP), has gained significant attention from researchers. In this document, a recently proposed WSRP is studied: in the Multiperiod Workforce Scheduling and Routing Problem with Dependent Tasks (MWSRPDT) a given company provides services by means of mobile teams. Service requests are known beforehand and each service is composed of one or more activities, where one activity may depend on the completion of another. A feasible schedule must be provided where all requested activities are completed in the minimum amount of days while respecting existing dependencies. Two hybrid exact-heuristic approaches based on a Mixed-Integer Programming formulation are proposed. Several new upper bounds for a set of instances obtained from the literature are discovered.