[1] City Univ London, Sch Math Comp Sci & Engn, Northampton Sq, London EC1V 0HB, England
[2] Bauhaus Univ Weimar, Chair Modelling & Simulat Struct, D-99423 Weimar, Germany
[3] Univ Politecn Madrid, Escuela Tecn Super Ingn Aeronaut & Espacio, E-28040 Madrid, Spain