A Hybrid LS-CP Solver for the Shifts and Breaks Design Problem

Abstract

Abstract. The problem of designing workforce shifts and break patterns is a relevant employee scheduling problem that arises in many contexts, especially in service industries. The issue is to find a minimum number of shifts, the number of workers assigned to them, and a suitable number of breaks so that the deviation from predetermined workforce requirements is minimized. We tackle this problem by means of a hybrid strategy in the spirit of Large Neighborhood Search, which exploits a set of Local Search operators that resort to a Constraint Programming model for assigning breaks. We test this strategy on a set of random and real life instances employed in the literature.

Solving the shift and break design problem using integer linear programming

“…In Di Gaspero et al (2010), the authors use a time limit of 60 min per instance to find a solution. Given the type of problem (generating a week's schedule) this seems a reasonable time, as viewed from the functional perspective.…”

“…The main contribution of this paper is to show that the shift and break design problem can be solved by contemporary standard ILP solvers when decomposed into two, combinatorially defined aggregation levels. The resulting algorithm seems to outperform the previously best performing method suggested by Di Gaspero et al (2010) that combined local search with constraint programming techniques. The main idea of this paper is to try to exploit the power of contemporary ILP solvers.…”

“…We use the same problem formulation as Di Gaspero et al (2010). The planning horizon consists of a set of consecutive days such as a week.…”

“…In this paper we consider the shift and break design problem which in this specific form was introduced by Di Gaspero et al (2010). In this problem a set of template shifts has to be selected from a set of possible shift types.…”

Modeling and solving a real-life multi-skill shift design problem

“…The scheduling of larger number of breaks (as a separate phase after shift design) has been investigated for applications in airports (Beer et al 2010;Widl and Musliu 2014) and call centers (Beer et al 2008). Solving the shift design problem together with break scheduling by a method that combines constraint programming and local search has been investigated in Di Gaspero et al (2010). An overview of previous work on shift design and break scheduling is provided in Di Gaspero et al (2013).…”