The Aquarelle Terminology Service
by Martin Doerr and Irini Fundulaki
Thesauri and other kinds of authority data, place names, artist names,
periods etc, are important for the intellectual access to information assets.
It is widely accepted that the use of thesauri for the classification of
assets and as search aid considerably improves precision and recall of
retrieval methods. This holds in particular for database records with few
words per field the typical form of records about museum objects.
Even more in a multilingual environment there should be support for translation
either transparent transformation of the valid terminology a user
refers in his request into the languages of the addressed databases, or
at least a guidance of the user to the local terminology in use. The Aquarelle
users required from an early stage of the project that this support must
be based on high quality information managed by human experts.
For optimal results, the terms used for asset classification, in the
search aid thesaurus and in the experts' terminology should be consistent.
This led us to a three level architecture of components cooperating with
the IT environment of an Aquarelle installation: vocabularies in local
databases, local thesaurus management systems of wider use and central
Term Servers for retrieval.
Typically, local databases have a more or less idiosynchratic way to
enforce vocabulary control. For reasons of standardization of format and
centralization of handling, we foresee an independent thesaurus manager
to which the vocabularies of several local databases are loaded, and in
the sequence organized as thesauri (authorities) by an expert, following
variations of the ISO2788 semantic structure. In addition, standard external
vocabularies can be loaded. These authorities may be specific to one database,
a user organization, or a whole language group. The local vocabularies
and terms already used for classification may need updating with changes
done at the thesaurus manager.
The Aquarelle Access Server, which is responsible for the distribution
and transformation of user requests, needs knowledge of the authorities
in local use, at least of the higher level terms. Therefore it communicates
with one or more Term Servers, which hold released versions or extracts
of the local authorities. Moreover, a Term Server must be fed with equivalence
expressions between the meaning of terms in different authorities, either
by an expert team or by linguistic methods and subsequent human control.
These expressions are used to replace the terms in a user request with
equivalent terms of the target system automatically or in a dialogue
with the user.
This three stage architecture reflects ideally the practice and needs
of classification, expert agreement, user organization and search aids.
It is a fully scalable solution and a flexible approach to standards enforcement.
The Semantic Index System-Thesaurus Management System (SIS-TMS) developed
in the past by FORTH was extended for Aquarelle in order to support the
above scenario. It will be a product of FORTH by summer 1998. It implements
a client-server architecture. There is a client for reading and one for
manual editing. Another client on the same base, the Term Server, was developed
by the ILSP, the Institute for Language and Speech Processing, Athens .
The system has several innovative features. It allows to maintain multiple,
multilingual thesauri and their interrelations in one logical database.
Different teams can cooperatively maintain multiple systems of semantic
relations on a shared body of terms and concepts. User groups can further
specialize the semantics of ISO2788 and ISO5964 (multilingual thesauri)
links and add custom fields.
The SIS-TMS graphical user interface allows for the unconstraint navigation
within and between different thesauri; the execution of predefined queries
and graphical views to identify concepts for cataloguing or database queries;
to identify translations or equivalent expressions for information access
in a heterogeneous environment; and to control the quality and the logical
consistency of a system of interlinked thesauri.
The editing system maintains a history of changes and provides release
operations for a set of changes done. Referential integrity and vocabulary
control is maintained throughout the system. These mechanisms are the prerequisite
to update incrementally the local databases and the Term Servers from the
thesaurus development units at regular release intervals with minimal possible
human intervention.
The local integration of the user databases with the terminology system
exceeds the Aquarelle framework, but it can be done now with minor effort
by any skilled programmer. Aquarelle will end with the evaluation of the
terminology management system and the Term Server, using as test data the
Art & Architecture Thesaurus (product of the Getty Information Institute,
Los Angeles; the largest of its kind with some 60.000 terms, for more information,
see http://www.gii.getty.edu/vocabulary/aat.html),
RCHME and the multilingual MERIMEE thesaurus. With this terminology service,
Aquarelle provides the technical means to solve one of the major problems
of the semantic interoperability. Further work must concentrate on means
to make the creation of authorities cheaper, and on the social organization
of the cooperative development and use of authorities.
Please contact:
Martin Doerr
Tel: +30 81 39 16 25
E-mail: martin@ics.forth.gr
Irini Fundulaki
Tel: +30 81 39 16 37
E-mail: fundul@ics.forth.gr
