Solving multi-activity multi-day shift scheduling problems with a hybrid heuristic

This paper addresses a multi-activity multi-day shift scheduling problem in a continuous and flexible environment including a heterogeneous workforce. Given days-off schedules associated with each employee, our objective is to construct and assign admissible multi-activity shifts to employees on their work days in a way that minimizes under-staffing and over-staffing with a restricted budget on workforce cost. A hybrid heuristic which combines tabu search with a branch-and-bound procedure is proposed to solve the problem. The computational experiments prove that our method provides good schedules in relatively short computing times.