Report on NWPT06

Anna and I organized the 18th Nordic Workshop on Programming Theory from Wednesday, 18 October, till Friday, 20 October, at Reykjavík University. The workshop was held under the auspices of the Icelandic Centre of Excellence in Theoretical Computer Science (ICE-TCS) and of the IFIP TC1 Working Group 1.8 on Concurrency Theory, and was partly sponsored by Reykjavík University.

The NWPT series of annual workshops is a forum bringing together programming theorists from the Nordic and Baltic countries (but also elsewhere). The previous workshops were held in Uppsala (1989, 1999 and 2004), Aalborg (1990), Gothenburg (1991 and 1995), Bergen (1992 and 2000), Turku (1993, 1998, and 2003), Aarhus (1994), Oslo (1996), Tallinn (1997 and 2002), Lyngby (2001), and Copenhagen (2005). Thus, this was the first ever NWPT workshop held in Iceland.

The event was attended by 45 scientists from the Nordic countries, but participants came from as far as south as Italy :-) In addition, several local MSc and advanced BSc students enjoyed some of the presentations, which were of consistently high quality. (Here are a couple of quick observations on the geographical distribution of the participants.

1. There were no contributed talks from Sweden, and David Sands was therefore the only representative of Swedish computer science at the workshop.
   
2. There was a good number of participants from Germany.)
   

The scientific programme consisted of four invited presentations and 26 contributed ones. The four invited talkes were:

• Gerd Behrmann, Aalborg University. How to become a successful tool builder - the dirty tricks
• Matthew Hennessy, University of Sussex. Some Remarks on Testing Probabilistic Processes.
• Hanne Riis Nielson, DTU. Analysis of Process Interactions
• David Sands, Chalmers University of Technology and University of Göteborg. Specifying and Verifying Dynamic Information Flow Properties

Hanne Riis Nielson gave the workshop the best of starts by offering an excellent overview of her work on using static analysis techniques to validate models of computational scenarios vis-a-vis the actual "reality" that is being modelled. As a motivating question she asked: "How can we be sure that process calculi descriptions of, say, biological processes/pathways are faithful to reality?" At the end of her clear and well-paced lecture, the audience was left feeling that static analysis can indeed help in addressing the all important motivating question underlying her presentation.

Gerd Behrmann's talk offered a thought provoking and stimulating analysis of the role of tool development in algorithmic verification. Gerd gave the audience many good reasons for building tools, but also pointed out that empirical studies in this field are often of questionable quality, with results that are not reproducible and unfounded conclusions. He pledged for this situation to be improved if tool building is to become a respected scientific activity.

Not surprinsingly, Gerd's talk gave rise to a lively discussion (both during and after the presentation). Flemming Nielson made some very interesting remarks after the talk, explaining how a tool developer can obtain credit for his/her work at his institution (DTU), e.g., by means of innovation schemes and the writing of books about the lessons learned during tool building. He also defended, in case there was any need to do so, the hard work of theorists, and uttered the following eminently quotable sentence:

"The purpose of theory is insight, not theorems!"

Matthew Hennessy delivered a talk on testing probabilistic processes that presented work he did while visiting NICTA in Australia. This was a one hour version of a shorter talk he had delivered earlier at the symposium in honour of Gordon Plotkin's sixtieth birthday. Matthew gave a typically well polished lecture, which managed to present a lot of technical work without ever giving his audience the feeling of being overwhelmed by the mathematics. I am looking forward to reading the paper on which the talk was based.

The last invited talk for the workshop was delivered by David Sands. Static verification of secure information flow has been a popular theme in recent programming language research, but the information flow policies considered are based on a static view of security levels. In his talk, Dave provided a road map of the main directions of current research, and introduced a simple mechanism, called flow locks, for specifying dynamic information flow policies, and a type-and-effect system for statically verifying flow lock policies. The talk was based on joint work with Niklas Broberg.

The 26 contributed talks were mostly of excellent quality, presenting work at different stages of development; some of it was definitely in progress, some other was "in infancy", and some was instead very mature. This is what a workshop should be like!

Some photos from the workshop, courtesy of MohammadReza Mousavi, are available.

The 2007 edition of the workshop will be held in Oslo, Norway. I trust that it'll be just as successful as we felt this one was. Good luck to Olaf Owe, who will take over the mantle of organizer from Anna and me.