--- Lloyd Oteniya (Ph.D research student). Department of Computing Science and Mathematics, Cottrell Building (office 4X6), University of Stirling, FK9 4LA email: lloyd.oteniya@cs.stir.ac.uk web: http://www.cs.stir.ac.uk/~lot Tel: +44 (0) 1786 46 7441 Fax: +44 (0) 1786 46 4551