Diane Kelly1, Alan Wassyng2, Colin G Orton. 1. Department of Mathematics and Computer Science, Royal Military College, Kingston, Ontario K7K 7B4, Canada (Tel: 613-541-6000 ext. 6171; E-mail: Kelly-D@rmc.ca). 2. Department of Computing and Software, McMaster University, Faculty of Engineering, Hamilton, Ontario L8S 4L8, Canada (Tel: 905-525-9140 ext. 2607, E-mail: wassyng@mcmaster.ca).