Ann Oper Res (2010) 181: 795–812 DOI 10.1007/s10479-010-0686-1 Applications of resource assignment and scheduling with Petri Nets and heuristic search Gonzalo Mejía · Carlos Montoya Published online: 29 January 2010 © Springer Science+Business Media, LLC 2010 Abstract This paper introduces a new Petri Net based approach for resource allocation and scheduling. The goals are (i) minimize the number of required resources given a set of jobs, (ii) find both an assignment for all jobs in the span of a predefined shift and (iii) the sequence in which such jobs are executed. The studied problem was inspired from a complex real life manufacturing shop as described in this document. The modeling of the processes and jobs is carried out with Petri Nets due to their capability of representing dynamic, concurrent discrete-event dynamic systems. The resource assignment starts with an initial feasible so- lution (initial number of resources) and then follows with a re-optimization process aimed to further reduce the resource requirements. The algorithm is based on a modified Heuristic Search method previously presented. The algorithm was tested first on a number of instances from the literature and then on the aforementioned system (a car seat cover manufacturer). The proposed approach shows not only good results in terms of performance but also shows the potential of Petri Nets for modeling and optimizing real-life systems. An implementation phase at the first stages of the process is underway at the time of writing. Keywords Petri Nets · Resource assignment · Scheduling · Heuristic search 1 Introduction Resource allocation and scheduling problems are related to a number of topics which in- clude the calculation of the number of required resources (workers and/or machines), and both the assignment and the scheduling of tasks to such resources. A number of applica- tions of this are commonly found in every day life that different types of manufacturing and service systems such as manufacturing shops, airlines, hospitals, call-centers, banks, etc. (Meisels and Lusternik 1997). In some cases, such as the Employee Timetabling Problem (ETP) and the Workforce Scheduling Problem (WSP), the problem consists of establishing G. Mejía ( ) · C. Montoya Departamento de Ingeniería Industrial, Universidad de los Andes, Carrera 1 # 19-40 Office ML703, Bogotá, Colombia e-mail: gmejia@uniandes.edu.co