[1] Liverpool John Moores Univ, Dept Comp Sci, Liverpool, Merseyside, England
[2] Univ Exeter, Coll Engn Math & Phys Sci, Dept Math & Comp Sci, High Performance Comp & Networking, Exeter, Devon, England
[3] Hong Kong Polytech Univ, Dept Comp, Hong Kong, Hong Kong, Peoples R China
[4] Hong Kong Polytech Univ, Internet & Mobile Comp Lab, Hong Kong, Hong Kong, Peoples R China
[5] Univ Leicester, Leicester, Leics, England
[6] Univ Bedfordshire, Dept Comp Sci & Technol, Luton, Beds, England
[7] Liverpool John Moores Univ, Sch Comp & Math Sci, Liverpool, Merseyside, England