Recent Researches in Engineering and Automatic Control : ECC´11: 2nd European Conference of Control, ECME´11: 2nd European Conference of Mechanical Engineering, ECCIE´11: 2nd European Conference of Civil Engineering, ECCE´11: 2nd European Conference of Chemical Engineering; Puerto De La Cruz, Tenerife, Spain, 10.-12. December 2011. WSEAS Press, 2011. ISBN 978-1-61804-057-2. E*