Research activity in 1994
Methodologies and tools for storing, accessing and manipulating information are
our subjects of interest.
The study combines and integrates in a homogeneous model the specification of
both the static structure and the dynamic behavior of the system under
analysis. The specification can be executed, so we can perform simulations of
the developing Information System for validation purposes.
Static data are described by an object-oriented sub-model because it has been
proved to be an enabling technology that makes it easy to construct and
maintain complex systems from individual components. In particular, an
innovative model for both representation and guided access based on taxonomies
was investigated.
Besides the classical integrity constraints on data, we can relate methods to
one another to describe the whole life cycle of an object taking into account
how they evolve in the real world.
The parallel behavior of all components of the system is the heart of our
research. We studied a model derived from high level Petri Nets able to move
objects, stored in a database, instead of classical tokens.
The semantics of such a net was investigated by means of a mapping between it
and an Extended Coloured Petri Net. The extension concerns the generalization
to an undefined number of terms of formal sums.
The model will remove, we hope, the so-called semantic gap between an
application domain and its representation since the real world is modeled as
closely as possible and relationships among entities in it are represented and
manipulated directly. The model under development achieves its capability
through the use of object-oriented concepts, persistence and Petri Nets.
Complementary researches concern problems related to the query resolution.
Specifically, the-join-by fragmentation method is extended with progressive
filtering, and efficient buffering techniques of objects are tested under the
assumption of non-uniform access distributions.
