1. Center for Information Management, Integration and Connectivity and MS/IS Department, Rutgers University, 180 University Avenue, Newark, NJ 07102, USA. E-mail: atluri@andromeda.rutgers.edu
2. Department of Operation and Information Management, University of Connecticut, Storrs, CT 06269-2041, USA. E-mail: whuang@sba.uconn.edu
3. Dipartimento di Scienze dell’Informazione, Università degli Studi di Milano, Via Comelico, 39/41, 20135 Milano, Italy. E-mail: bertino@dsi.unimi.it