Intelligent Mediation of Cultural Information Sources
by Bernd Amann, Vassilis Christophides, Irini Fundulaki, Michel
Scholl and Anne-Marie Vercoustre
With the emergence of the World Wide Web and other application
integration infrastructures such as OMG’s CORBA and Microsoft’s
OLE, a large number of autonomous cultural information sources
has become accessible to diverse user groups around the world.
In this global information space, access to disparate information
such as fine-art objects, documents, pictures, etc, is a difficult
and complex process. This is due, in particular, to the existence
of two types of heterogeneity: the first is of semantic nature,
dealing with the different terminologies and conceptualizations
employed by the various information providers and consumers while
the second one is more of a syntactic nature, due to the variety
of the incorporated data structures, for the representation, storage
and retrieval of information in the various sources.
INRIA and FORTH have launched a research collaboration (ARTEMIS
Project) which is motivated by the need to access and integrate
complex and evolving information in a dynamic environment. We
rely on the ARPA I3 reference architecture comprising three layers,
namely, a Graphical User Interface, a Mediator and several Wrapped
Data Sources. Our approach considers high-level languages for
information transfer in order to specify and implement I3 tools
such as mediators and wrappers. We advocate in this respect a
suitable integration of Knowledge Representation and Reasoning
technology with Database technology. The former is adopted for
the efficient semantic description of sources using ontologies
and thesauri and the latter for the integration and caching of
query results.
Cultural artifacts such as paintings, statues, buildings can be
classified differently according to various techniques, forms,
styles, materials and are related to different persons, historical
events, places, etc. To capture the different semantics of cultural
information, we are interested in sophisticated classification
schemes such as ontologies (ICOM/CIDOC Reference Model) and thesauri
(the Getty’s Art & Architecture Thesaurus (AAT), the Thesaurus
of Geographical Names (TGN), the United List of Artist Names (ULAN)).
In addition, information about cultural artifacts is available
in various data forms such as photos, plain ASCII files, HTML/SGML
documents, relational and object databases and other unstructured
or weakly structured exchange formats. To encompass syntactic
heterogeneity of information we intend to use state of the art
semistructured models combining object databases with weak typing
features.
We address the issue of intelligent integration of application
specific ontologies/thesauri and source specific metadata in order
to define dynamic mediator schemata as well as enable flexible
query formulation and processing. For such a purpose, we distinguish
between the semantic and structural metadata of source descriptions
to capture the two types of heterogeneity that were mentioned
previously. In this context, registration, modification or withdrawal
of a source should lead to minimal mediator reorganization. Moreover,
users will have the possibility to interact at run-time with the
system in order to guide mediator construction with specific data
quality preferences (data accessibility, interpretability, usefulness,
believability, etc.).
Specific Approach
We will use the ICOM/CIDOC ontology, that has been developed independently
of the underlying information repositories, as the reference model
for the organization of cultural information. Nevertheless, this
ontology represents information entities and relationships in
a quite abstract level (eg, Person, Artifact, Event, etc.) and
in order to support more detailed semantic descriptions of sources
we intend to incorporate related thesauri or authority data (AAT,
TGN, ULAN etc).
Furthermore, we will use object database support in order to build
a semantic cache for object fusion, cache browsing and querying.
The cache schema will be constructed dynamically from the user
query and should reflect the structure of query results. Under
this perspective we adopt a semistructured approach for its flexibility
to capture schema changes and represent eventually incomplete
information.
Query Processing
For query processing we have to address different issues which
are well known for mediator based architectures. Among these issues
the most important are (1) source selection with respect to a
user query, (2) query rewriting with respect to the source semantics
and structure. (3) query plan generation with respect to the wrapper
query capabilities and (4) cache management. In order to select
sources which might be relevant to some user query we will study
new subsumption algorithms which take into consideration not only
concept definition but also inter/intra thesaurus relationships
between terms (eg broader/narrower, related, equivalent term etc.).
We are currently collaborating with different cultural organizations
(National Museum of Denmark, Greek and French Ministries of Culture,
Germanisches Nationalmuseum of Nürnberg and the Benaki Museum
at Greece) for an application oriented evaluation of our approach.
Please contact:
Anne-Marie Vercoustre - INRIA
Tel: +33 1 3963 5662
E-mail: Anne-Marie.Vercoustre@inria.fr
Vassilis Christophides - FORTH
Tel: +30 81 39 16 28
E-mail: christop@ics.forth.gr
