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Editions of S4

There were seven editions of the S4 module:

  1. (1992-3) December 14-18 1992
  2. (1993-4) November 1-5 1993
  3. (1994-5) December 12-16 1994
  4. (1995-6) January 8-12 1996
  5. (1996-7) March 3-7 1997
  6. (1997-8) November 10-14 1997
  7. (1998-9) November 9-13 1998

The form of the assignment was broadly similar in almost all editions and was typically based on this template. Only Edition 5 adopted a different format (TBC), comprising teamwork in assembling a 'cricket laboratory' and an individual exercise showing familiarity with the use of Eden, Donald and Scout and the principles behind the use of LSD and the ADM. The title of the module changed (if at first only unofficially) from Definitive Methods for Concurrent Systems Modelling to Empirical Modelling for Concurrent Systems Modelling.


Edition 1 (Dec 92) had several practical sessions based on the game of cricket (including an actual game to illustrate the basic principles of bowling, batting and fielding). The VCCS was used throughout as an introductory case study (cf. the overview and introduction and the introduction to agency and to LSD). The introduction to definitive notations and to Scout in particular was based on Chapters 4 and 5 of Simon Yung's PhD thesis. The seminar on the 'Foundations of Programming' discussed definitive scripts as a basis for software construction. The seminar on 'Definitive Methods for Programming and Parallelism' focused on how programs could be derived by translation techniques (cf. Trident). There was a diverse collection of submissions for the module (see feedback). The feedback from students on the module was positive and encouraging for the lecturers. This edition of S4 was followed up in the Spring term of 1993 by the Cricket Project (involving 11 teams of second year computer science students on the CS233 module). Nick Pownall took up the cricket theme in his MSc project in 1992-3. Paul Ness, Andrew Satterthwaite and Benny Lam also did MSc projects based on S4.

Edition 2 (Nov 93) substituted models connected with railways for cricket modelling. Simon Yung extended his railway station animation, initially developed as an abstract account of the roles of agents in a train-arrival-departure protocol, to incorporate a track model (based on authentic model railway components). Discussion of how the modern railway has emerged through a combination of empirical and formal influences was introduced. The video One Day in Severn was used to illustrate mechanical signalling practices. The practical laboratory on Thursday afternoon incorporated several exercises with a railway theme. These were preceded by a demo session comprising four topics that were covered by post-module assignments and project work by students who attended S4 in 1992-3 (beetles - Benny Lam, cricket - Nick Pownall, sailboat - Paul Ness, billiards - Monica Farkas). The post-module synopsis of the seminar content for the module (dating from 11th November) illustrates how freely the advertised seminar content was interpreted. There was generally positive feedback, but concern about the relevance of seminars and about the degree of connection with parallel programming.

Edition 3 (Dec 94) was similar in content to Edition 2 in all respects but for changes to the seminar content. The module ended at lunchtime on Friday (at 1pm rather than 4pm) to accommodate the departmental Christmas lunch. There is an extant inventory of the course documentation, student registration list and an informative list of projects for reference by students. Some older resources on LSD required updating (cf. Definitive Specification of Concurrent Systems).

Edition 4 (Jan 96) illustrates the way in which the module evolved in a fluid manner. The timetable advertised at the outset of the week was identical to that of Edition 3, but a revised agenda for Wednesday and Thursday was posted on Tuesday. The thematic plan for the module matured between editions 5 and 6, in part due to the discovery of William James's writings on radical empiricism.

Edition 5 (Mar 97) was reconstructed by Pui-Shan Chan, who created the webpage for S4 edition 5 that is accessed via the link above (cf. annotated timetable v1 and annotated timetable v12 and working notes). This has integral links to the content similar to those that featured in the CS405 website from 2005-6 onwards. The theme of modelling cricket was revived in this edition of S4 (cf. the Monday Cricket Laboratory session), making use of resources that had been developed since the first edition of S4. These included Nick Pownall's LSD/ADM account and the urchincricket.e prototype as developed by students on CS233 (notably Lee Suker). The Digital Watch and Statechart model, originally discussed at the end of the S4 module, became a standard component of the Tuesday visualisation and concurrent systems agenda. Supplementary support for this topic came from Rob Carpenter's final year project: Statecharts-In-Tkeden (see ~/public/projects/tools/editors/sit). As described here, the sequence of eight lectures on EM and concurrency that was to emerge from S4 was much enhanced through connections made with William James's Radical Empiricism. This edition was attended by 14 students of whom 9, including Jaratsri Rungrattanaubol, James Taylor, Chandika Mendis and Rob West, submitted assignments (see ~/public/Project97/S4/ for more details).

Edition 6 (Nov 97) featured The Great Game of Britain as a practical exercise in collaborative modelling. It led to the Virtual Electronic Laboratory MSc project (Hansel d'Ornellas and Chirag Sheth). Ashley Ward attended and developed the Empirical Wool Environment (EWE) as his MSc project. Dora Polenta also undertook an MSc project relating to the Burnley railway accident scenario.

Edition 7 (Nov 98) included an ambitious tutorial and laboratory devoted to exploratory use of dtkeden, led by Richard Cartwright and Patrick Sun. Paul Ness also played a leading role in framing related discussions. Examples drew on the ~wmb/public/projects/games/, ~wmb/public/projects/simulations/ and ~wmb/public/projects/demos/ directories. The focus of this final edition of S4 was on collaborative applications of EM, with particular reference to Concurrent Engineering, Concurrent Systems Modelling and Cognitive Technology. Proposals for MSc project work were made by EM research students - Soha Maad on EM for Business and Financial Systems and Dom Gehring on using the Maintainer of Dynamic Definitions (MODD). A notable submission was the distributed version of the game of XXXI by Mark Thurman.


The modelling tools deployed in S4 developed rapidly from year to year between 1992 and 1999. The core changes were to the principal modelling tool EDEN, but this had an impact on the Abstract Definition Machine and on the distributed version of EDEN that featured in Edition 7. For useful insight into the status of EDEN in 1994, consult the documentation in the ~wmb/public/doc directory written by Simon Yung: Definitive Systems (May 1994) and Introduction to the Definitive World (December 1994). See also the models in the ~wmb/public/projects directory, at that time the prototype projects archive. The pipeline approach to integrating definitive notations via the eden interpreter was superseded through the introduction of the xeden environment that allowed switching between notations and framing bridging definitions (using %eden, %donald, %scout and %bridge). The link between the ADM and EDEN discussed in the first edition of S4 was based on translation (see the tic-tac-toe model from December 1992). The advent of xeden led to the blending of the ADM with eden that was illustrated in Edition 3 of S4 in December 1994 (see the tic-tac-toe ADM model from December 1994). Further scope for integration was introduced when tkeden was developed and deployed in Edition 5 of S4 in March 1997. The introduction of dtkeden in 1998-9 was based on practical work underpinning Patrick Sun's PhD thesis, as documented in collaboration with Richard Cartwright.