  The shift design and the personnel scheduling problem is known to be a
difficult problem. It is a real-world problem which has lots of applications in
the organization of companies. Solutions are usually found by dividing the
problem in two steps: first the shifts are created, then the employees are
assigned to them by respecting a bunch of constraints. The assignment of
different tasks increases the complexity, since we have to consider the skills
of the single employee necessary to perform any activity. In this paper we
present a mixed-integer linear programming formulation which models together
the shift creation and the construction of rosters for employees, with the
objective of minimizing the amount of uncovered demand. Finally we provide the
results for three real-world instances, confirming that this approach is
promising.
