1. University of Quebec,Dept.of Elect. Engineering,Trois-Riviéres,QC,Canada
2. Energy Science and Technology, Oak Ridge National Laboratory,Knoxville,TN,USA
3. Ecole Nationale Polytechnique, University of Douala,Douala,Cameroon
4. University of Quebec,Dept of Mechanical Engineering,Rouyn-Noranda,QC,Canada