 Nielsen's earlier affiliations include Bellcore (now Telcordia Technologies) (Bell Communications Research), the Technical University of Denmark, and the IBM User Interface Institute at the Thomas J. Watson Research Center.From 1994 to 1998, he was a Sun Microsystems Distinguished Engineer.He was hired to make heavy-duty enterprise software easier to use, since large-scale applications had been the focus of most of his projects at the phone company and IBM.