1. Karlstad University,Dep. of Mathematics and Computer Science,Karlstad,Sweden
2. School of Electronics, Electrical Eng. and Computer Science, Queen's University Belfast,Belfast,United Kingdom
3. Deggendorf Institute of Technology,Faculty of Computer Science,Deggendorf,Germany
4. School of Eng. Sciences in Chemistry, Biotech. and Health KTH Royal Inst. of Technology,Stockholm,Sweden