[1] Univ Koblenz Landau, W Inst Web Sci & Technol, Koblenz, Germany
[2] Ctr Wiskunde & Informat, Semant Media Interfaces Res Grp, Amsterdam, Netherlands
[3] Oxford Brookes Univ, Sch Technol, Dept Comp, Oxford OX3 0BP, England
[4] Natl Univ Ireland, Digital Enterprise Res Inst, Galway, Ireland
[5] IMATI Inst Appl Math & Informat Technol, Shape Modeling Grp, Genoa, Italy