KINE - A Knowledge INtegration Environment
by Patrizia Asirelli
The main goal of the KINE project is to design and implement a
programming environment for the ‘semantic’ integration of heterogeneous
knowledge bases. Technology developed in the Logic Programming
and Deductive (Logic-based) Database areas is being used. The
programming language employed is MedLan, a Definite Deductive
Database Logic language, which has been extended in order to handle
multiple separate theories as a single database and furnished
with a set of operators for the composition of logic theories.
KINE is a three year collaboration between the IEI and CNUCE Institutes
of the Italian National Research Council (CNR) and the Department
for Computer Science of the University of Pisa; it is supported
by the CNR Committee for Information Sciences and Technology.
Nowadays, there is a general tendency to re-organise and re-structure
business and production agencies as nets of decentralized and
autonomous units so that the resulting organizations are more
flexible and better equipped to adapt to new and changing market
requirements. One of the consequences of the Internet and Web
revolution is that there is an increasing demand for knowledge
and systems integration and this is expected to grow even more
in the near future. The provision of semantic heterogeneity and
secure integration of information sources/databases is thus crucial
for the development of future distributed/ integrated/federated
applications.
The architecture for knowledge integration that we consider is
a Mediator-like architecture (see Figure). In particular, wrappers
are logic theories (programs) that define the meta-data, ie they
map the relations of the different database sources into the general
model of the integrated environment defined at the mediator level.
Mediators are also logic theories (programs) and define the application
environment for the resulting integration. The user interacts
with this environment.
In this framework, the MedLan language is used to build a set
of logical theories (mediators and wrappers) that constitute the
middle layers of the integrated architecture. As can be seen in
the figure, these layers stand between the database sources and
the final user who can only see part of the information. Two aspects
are merged: the semantic integration between database sources
and the implementation of security policies.
MedLan has been given an operational and denotational semantics
and a kind of semi-naive implementation has also been defined.
The extensions offered by MedLan with respect to classic deductive
database languages consist in: the partitioning of the deductive
database into a collection of theories; the operators to combine
them: Union (U), Intersection (Ô), Constraint (/), and the in
operator that implements a message passing feature.
The Constraint (/) operator is the most important of the MedLan
operators for security aspects as it enables security policies
to be easily included into a logic database. The in feature is
also relevant since it permits a database to be split into a number
of theories and then perform deduction over these theories when
necessary. This aspect is very important since it allows a generalisation
of distribution and integration over different
databases.
Future work will include the study of different existing security
models and enforcing policies, as documented in the literature,
in order to evaluate the feasibility and the effectiveness of
our approach in real systems.
The project has an application to GIS systems. The MedLan language
has been implemented as an initial prototype to be used in an
integration with the ARCHINFO GIS system. In parallel, MedLan
has also been implemented within the GEDBLOG prototype system
(a deductive database management system) that already presents
some of the features of MedLan. In particular we are concentrating
on the implementation of the in feature of MedLan. A Web version
of the prototype (Jebdlog) can be seen at: http://mascagni.iei.pi.cnr.it/Jdblog/
webJedblog.html, and an example of an application example of the
system can be found at: http://mascagni.iei.pi.cnr.it/flight.
KINE is a three-year project and is now entering its final year.
It has benefited greatly from the strong tradition and the wealth
of experience in the fields of Logic Programming and Logic Databases
built up over the years here in Pisa.
Please contact:
Patrizia Asirelli - IEI-CNR
Tel: +39 0 50 593 477
E-mail: asirelli@iei.pi.cnr.it
