hi ILUG'S, Please reply to this link http://www.ae.iitm.ac.in/pipermail/ilugc/2009-December/054000.html, and if anybony have idea plz share with me, i need to understand this concept urgently....I have already ask this question to the community...but I have not got any reply...If anybody knows, Plz suggest... _______________________________________________ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc