...Bader

The support by NASA Graduate Student Researcher Fellowship No. NGT-50951 is gratefully acknowledged.

...JáJá

Supported in part by NSF Engineering Research Center Program NSFD CDR 8803012 and NSF grant No. CCR-9103135. Also, affiliated with the Institute for Systems Research.

...Chellappa

Supported in part by Air Force grant No. F49620-92-J0130.

David A. Bader
dbader@umiacs.umd.edu