1. Department of Computer Science, Queen's University of Belfast K. McKinty, S. Saadat and F. J. Smith Department of Computer Science Queen's University of Belfast Belfast BT7 1NN, UK B. T. Donovan 48 Kelsey Lane Beckenham Kent BR3 3NE, UK;2. ALPSP K. McKinty, S. Saadat and F. J. Smith Department of Computer Science Queen's University of Belfast Belfast BT7 1NN, UK B. T. Donovan 48 Kelsey Lane Beckenham Kent BR3 3NE, UK |