| Affiliation: | School of Computing and Information Systems, Athabasca University, 1 University Drive Athabasca, Alberta, Canada T9S 3A3. Tel.: +1 780 675 6812; fax: +1 780 675 6148.; Learning Systems Institute, C 4622 University Center, Tallahassee, FL 32306-2540, USA. Tel.: +1 850 645 1777; fax: +1 850 644 4952.; Department of Technology in Education and Digital Systems, University of Piraeus, Unit Advanced e-Services for the Knowledge Society (ASK), Research Unit Informatics and Telematics Institute (ITI), Center for Research and Technology – Hellas (CERTH), 150 Androutsou Str., GR-18532, Piraeus Greece. Tel.: +30 210 414 2766; fax: +30 210 414 2767. |
