[1] Univ Catolica Norte, Dept Ingn Sistemas & Comp, Antofagasta 1249004, Chile
[2] Univ Calif Davis, Dept Biol & Agr Engn, Davis, CA 95616 USA
[3] Univ Andres Bello, Fac Engn, Energy Transformat Ctr, Santiago 7500000, Chile
[4] Univ Tecn Federico Santa Maria, Dept Elect Engn, Valparaiso 2390123, Chile
[5] Heriot Watt Univ, Sch Engn & Phys Sci, Edinburgh EH14 4AS, Scotland