1. Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Alberta, Canada T2N 1N4
2. Centre for Computing and Information Systems, Athabasca University, 1 University Drive, Athabasca, Alberta, Canada T9S 3A3
3. Institute for Information Technology, National Research Council of Canada, 1500 Montreal Road, Bldg. M-50, Ottawa, Ontario, Canada K1A 0R6