This work was developed in the ESPRIT/HPCN project ``SHIPS'', and will form a test application for the ACTS project ``ASICCOM'', funded by the European Union (DG III and DG XIII). We deeply appreciate this financial support, without which this work would have not existed.
We would like to thank Manolis Katevenis, Sotiris Ioannidis and Kosmas Papachristos for useful comments in earlier drafts of this paper. Michael J. Feeley and Henry M. Levy pointed out useful references. Finally, we deeply appreciate the thoughtful comments of the anonymous referees.