A Structure-Based Partial Solution Search for the Examination Timetabling Problem

The examination timetabling problem is a well researched problem. Various techniques have been applied to solving this NP-hard problem including genetic algorithms and hyper-heuristics. The developmental approach was created specifically for solving the examination timetabling problem. Studies on the developmental approach revealed the effectiveness of searching in the partial solution space, incrementally building solutions, in solving the examination timetabling problem. Research into solving the examination timetabling problem has also revealed that one of the challenges is that timetables of very different structure often have the same behaviour and hence objective value. Taking both these aspects into consideration this paper presents a structure-based partial solution search (SBPSS) to solve the examination timetabling problem. This multipoint search works in the partial solution space of timetables, incrementally building timetable solutions. Furthermore, while movement through the search space in traditional search is based on behaviour in terms of fitness or the objective value, SBPSS directs the search based on genotype in terms of the structure of the timetables as well as behaviour. The SBPSS was applied to the ITC 2007 examination timetabling track benchmark problem set from the second international timetabling competition. The performance of the SBPSS was found to be competitive to other state of the art approaches, producing the best result for five of the examination timetabling problem instances.