1. Sana'a Community College,Telecommunication Engineering Technology Deptartment,Sana'a,Yemen
2. College of Engineering, Birmingham City University,Faculty of Computing, Engineering and the Built Environment,Birmingham,UK,B4 7XG
3. Sana'a Community College,Computer Network Engineering Technology Deptartment,Sana'a,Yemen
4. School of Engineering, Lebanese International University (LIU),Sana'a,Yemen