by Stephen Cook
The Extended Transition Network (ETN) is a flavour of labelled transition system which is particularly suitable for modelling information systems. The usual modelling approaches (eg SSADM) differentiate strongly process and data modelling. ETN technology provides the possibility to combine these two aspects elegantly with constraints and triggers to provide a complete and unified modelling environment from conceptual level down to detailed systems design specifications. The concept was devised initially by Keith Jeffery (CLRC) and developed further jointly with Patrizia Asirelli (IEI-CNR), under the auspices of the ERCIM Database Research Group.
Recently this collaboration between CLRC and IEI has been strengthened by an ERCIM Internal Fellowship. This enabled Stephen Cook, from CLRC's Data Engineering Group, to spend three months at IEI working on ETN and gaining first-hand experience of the GEDBLOG logic database which provides the deductive engine for the ETN environment.
As a result, the ETN project has made significant progress in three areas:
Interim results from the Fellowship are available in Postscript form from ftp://rep1.iei.pi.cnr.it/pub/asirelli/ETNrules.ps and will be published as an IEI Technical Report.