(Trans)Actions and Change in Logic Programming and Deductive Databases
October, 17 October 1997, Port Jefferson
On October 17, Anthony Bonner, Burkhard
Freitag, Laura Giordano and Robert Kowalski organised the post-ILPS97 workshop Dynamics97
on "(Trans) Actions and Change in Logic Programming and Deductive Databases".
The intended focus of the workshop was on the dynamic behaviour and the
evolution of databases and programs with time. A previous workshop on the same arguments
was held as Dagstuhl seminar on "Logic Databases and the Meaning of Change" in
1996. Dynamics97 got some financial support from the ILPS97 organizers, and was very well
coordinated by Burkhard Freitag.
The workshop attracted twenty-two
participants. Eleven papers were presented on topics concerning the treatment of dynamic
behaviour of agent- and knowledge-based systems, the dynamic of databases and logic
programs and the reasoning about it, knowledge revision and assimilation.
First session was about agents and
knowledge based systems. Joeri Engelfriet compared various
approaches for the specification of the dynamics of knowledge-based systems, such as
languages, transaction and dynamic logic and evolving algebras. Jorge Lobo presented a
system for workflow management where workflow is treated as a collection of cooperative
agents. Reasoning upon workflows is obtained by exploiting languages for reasoning about
actions and the workflow control is specified and verified through reactive rules. Focus
of the following talk, which I gave, considered distributed logic agents which possibly
interact through abduction. Abductive reasoning is supported by a basic coordination
protocol which extends a sequential abductive proof procedure to the distributed case.
Second session concerned more
theoretical work. Eugenia Ternovskaia presented analogies between
the situation calculus, a many-sorted language for specifying change, and inductive
definitions. She also discussed the verification of the high-level robot programming
language GOLOG, a language based on the situation calculus, when properties of GOLOG
programs are inductively defined. Sven-Erik Bornscheuer presented a model for the
integration of intelligent reflective and reactive reasoning based on massively parallel
nonmonotonic model generation by considering interpretations as agents' current beliefs
and perceptions, and applying an immediate consequence operator to obtain direct
consequences of these beliefs.
Following session was devoted to
databases and their dynamics. Anthony Bonner presented a logical
language, called Transaction Datalog, capable of combining standard transactions into
complex processes and useful in applications such as CAD, office automation, and workflow
management. Burkhard Freitag presented a work for supporting seriazability of logical
transactions through the notion of deferred updates. Basically, updates are not
immediately executed, but they are deferred and trace of their operations on the database
is kept to determine compatibility and incompatibility among them. Maurizio Martelli
applied a higher-order language based on linear logic to the specification of Chimera, a
deductive object-oriented database system.
Last session was devoted to knowledge
revision and assimilation. Stephane Janot presented and compared three change operators,
based on forward chaining, for according old knowledge to new evidence in the framework of
propositional knowledge. Gerard Wetzel, instead, suggested to use integrity constraints in
order to delete logically redundant information which possibly slow down the computation.
The framework considered is a general one which integrates abductive and constraint logic
programming and semantic query optimisation. Last work presented by Hendrick Decker
integrates two procedure supporting respectively schema updates (i.e., intensional
database update) and user updates (i.e., view or extensional database updates) in a new
abductive procedure for knowledge assimilation.
During the workshop, several
discussions and exchange of ideas took place motivating the
organisers to plan a new edition to be held during the next Joint Conference and Symposium
on Logic Programming in 1998.
Selected papers from both Dynamics97
and the Dagstuhl seminar are going to be published in the Springer LNAI subseries of LNCS.
Additional information (and the informal workshop proceedings) can be found at the web
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