5 July 2002, Symposium on Relational Reasoning

Program

13.45 - 14.45 Rudolf Berghammer (Kiel), Computer-aided development of relational programs

In the talk relational algebra is proposed as a practical means for formal problem specification and the development of relational programs from such specifications.

We show by means of some simple examples how data-types can be modelled by relations, how - based on this modelling - then relational specifications can be derived from informal problem descriptions via first-order formulae as intermediate formalizations, and how, finally, imperative relational programs can be developed from relational specifications. To derive a relational specification from a first-order formalization, we mainly use correspondences between relational and logical constructs. The development of a relational program transforms the specification into a pre-/post-condition pair and combines then relation-algebraic calculations and the well-known Dijkstra-Gries method.

We also demonstrate how our approach can be supported by the computer system RelView in both stages. The system has been developed at Kiel University since the year 1993. Among other things, it facilitates the prototyping and testing of relational specifications and programs and the visualization of many relation-algebraic properties and manipulations.

14.45 - 15.15 Tool demonstration of Relview by Rudolf Berghammer

15.15 - 15.45 break

15.45 - 16.45 Jan Rauch (Prague), GUHA; relational datamining

Data mining is the central step of knowledge discovery in databases - the process of identifying novel, potentially useful and ultimately understandable patterns in data. Relational data mining looks for such patterns in relational databases. Association rule is a very known form of such patterns. It is an expression of the form X?Y where X and Y are sets of items. The intuitive meaning is that transactions (e.g. supermarket baskets) containing set X of items tend to contain set Y of items.

GUHA is an original Czech method developed for over 35 years, that mines for more general association rule including rules expressing various types of equivalence and for association rules based on statistical hypothesis tests. The procedure 4ft-Miner that is a new implementation of GUHA method will be described. 4ft-Miner mines also for conditional association rules. It is a part of the system LISp-Miner; see http://lispminer.vse.cz. Theoretical results concerning logical properties of association rules will also be presented.

16.45 - 17.15 Tool demonstration of GUHA by Jan Rauch