View article

Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (eg, payment of royalties). Copies may be requested from IBM TJ Watson Research Center, P. O. Box 218, Yorktown Heights, NY 10598 USA (email: reports@ us. ibm. com). Some reports are available on the internet at http://domino. watson. ibm. com/library/CyberDig. nsf/home.