Air-Crew Scheduling through Abduction

This paper presents the design and implementation of an aircrew assignment system based on the Artificial Intelligence principles and techniques of abductive reasoning as captured by the framework of Abductive Logic Programming (ALP). The aim of this work was to produce a system for Cyprus Airways that can be used to provide a solution to the airline’s crew scheduling problem whose quality was comparable with the manual solutions generated by human experts on this particular problem. In addition to this the system should also constitute a tool with which its operators could continually customize the solutions to new needs and preferences of the company and the crew. The abductive approach (using ALP) adopted in our work offers a flexible modeling environment in which both the problem and its constraints can be easily represented directly from their high-level natural specification. This high-level representation offers two main advantages in the development of an application: (i) modularity with a clear separation of the two main issues of validity and quality (optimality) of the solution and (ii) flexibility under changes of the requirements of the problem.