Affiliations: Department of Mathematics&Computer Science, College of Science, Kuwait University, P. O. Box: 5969 Safat 13060, State of Kuwait, e-mail: salem@al-yakoob.com | Grado Department of Industrial&Systems Engineering, Virginia Polytechnic Institute& State University, Blacksburg, VA 24061, USA, e-mail: hanifs@vt.edu
Note: [] This work was supported by Kuwait University under Research Grant No. [SM06/02] and by the National Science Foundation under Research Grant No. [DMI-0094462]. Special thanks to Mrs. Fatima Al-awadi for her contributions to the computational implementation of the scheduling algorithm.
Abstract: This paper is concerned with an employee scheduling problem involving multiple shifts and work centers, where employees belong to a hierarchy of categories having downward substitutability. An employee at a higher category may perform the duties of an employee at a lower category, but not vice versa. However, a higher category employee receives a higher compensation than a lower category employee. For a given work center, the demand for each category during a given shift is fixed for the weekdays, and may differ from that on weekends. Two objectives need to be achieved: The first is to find a minimum-cost workforce mix of categories of employees that is needed to satisfy specified demand requirements, and the second is to assign the selected employees to shifts and work centers taking into consideration their preferences for shifts, work centers, and off-days. A mixed-integer programming model is initially developed for the problem, based on which a specialized scheduling heuristic is subsequently developed for the problem. Computational results reported reveal that the proposed heuristic determines solutions proven to lie within 92–99% of optimality for a number of realistic test problems.
