1. Camila Bezerra, Fred Freitas,
Informatics Center, Federal University of
Pernambuco,Brasil
{fred, cbs}@cin.ufpe.br
Jérôme Euzenat
INRIA, Rhône-Alpes, Montbonnot, France
Jerome.Euzenat@inrialpes.fr
Antoine Zimmermann
Digital Enterprise Research Institute, National University
of Ireland
antoine.zimmermann@deri.org
Under the sponsoring of CNPQ and INRIA
(research project OntoCompo - Composition and
Modules for Ontology Engineering)
2. The success of the Semantic Web depends of a
number of factors, one of them is the reuse of
ontologies.
Ontology development is deemed to be a time-
consuming and labour-intensive task.
Modularization could help the ontologies
developers to identify and select only those
concepts and relations relevant for the given
application.
3. Currently, there are two major ways of reusing an
ontology:
1. Ontology editors such as Protégé allow the reuse of
another ontology by including it in the model that
is being designed
2. OWL offers the possibility to import an OWL
ontology by means of the <owl:imports>
statement.
In both cases, the whole ontology has to be
included!
4. Easy development and reuse with smaller
building blocks
◦ More intuitive visualization
Scalability: many ontology tools are known
to perform well on small-scale ontologies
◦ In special efficient reasoning
Encapsulation: is highly desirable the
separation of concerns and a defined
interface
5. The few software tools capable of composing
ontologies don’t do the job in a clean way
◦ Ontologies are usually shown all together
◦ Users can hardly distinguish included ontologies
Particularly if there is plenty of them :)
◦ Most of the modularization proposals are more
ontology linking approaches rather than modular
C-OWL [Bouquet et al. 2004], Bridge rules, E-
Connections [Kutz et al 2004]
They don’t enforce ways of limiting the modules!
6. Modules should be specified, in such a way
that avoids dependence from a particular
ontology or module
Exported modules can be replaced by others
with similar contents
Our approach departs from the principle that
a module language must be able to :
◦ encapsulate ontology fragments,
◦ to refer to other modules and
◦ to define interfaces among these modules.
7. Encapsulation: the perimeter of each module
must be precisely defined as well as its
aggregated modules, so that potential users
can outline in advance which other modules
he is including in her new module.
Information hiding: module interfaces specify
imported and exported entities only
◦ Not all the definitions have to be im/exported
◦ Module “implementation” can evolve without
affecting the importing module specification
◦ Modules are replaceable by others offering the
same interface.
8. 1. a RDF syntax, compatible with OWL
2. A more concise human readable syntax for
displaying in documents
11. A new type of pizza, the
NorthEasternBrazilianPizza
◦ It has a Topping only SaltedMeat
◦ Its country of origin is Brazil
It’s necessary to import entities from two
ontologies:
1. Ontology of Pizzas
2. Ontology of Countries
18. Module API - Based on the implementation
of the module specifications as described in
the syntax, it provides the basic data
structure and renderers as well as a parsers
on top of the structure.
19. Module extractor - creates modules from
existing ontologies
◦ ‘select’ (or ‘extract’) operation over an ontology in a
number ways, such as selecting/ruling out entities
(classes, properties, individuals) to be exported
◦ using a graphical interface and selecting/ruling out
entities using expressions (e.g. sub- , superclasses,
complements, and others)
◦ special buttons and parameters that represent them
and generating a module description.
20. Module (Syntactical) Checker - verifies if all of
the definitions needed by a module are on its
imported modules.
Reasoner interface for modules – adapted
OWL reasoners to answer queries over
modules and modular ontologies
◦ Consistency checking
21. Module linker – a graphical tool to build modules
from other modules
o The user is able to select only the elements from the
``exported interface'' from the imported module.
Module library – a repository for “off-the-shelf”
modules that will help developers to choose
modules
◦ A module description in this library should include its
imported modules
◦ The user can load the selected module in the library or
load it in the Linker to be reused in the new one.
22.
23. Along the OntoCompo project, we have
designed an ontology modularization
approach inspired in object orientation
◦ Main focus: encapsulation
We developed a module language with syntax
and (notions of) semantics …
… with a concrete implementation of the
language
The ModOnto tool assists users in the
construction of new modules starting from
ontologies or other modules
24. Linkage with partitioning works [Stuckenschmidt
& Klein 2003]
‣ The suite could be integrated with popular
ontology frameworks like Protégé, KAON2 and
the ones from NeOn project.
Improving the graphical interface for usability
reasons.
Ontology engineeering issues
◦ How do we design an ontology focusing on modularity?
◦ Good features and practices for Modules
25.
26. Bouquet, P., Giunchiglia, F., van Harmelen, F., Serafini, L., Stuckenschmidt, H.: C-OWL:
Contextualizing ontologies. In: International Semantic Web Conference. (2003), 164-179.
Kutz, O., Lutz, C., Wolter, F., Zakharyaschev, M. E-connections of abstract descriptions
systems; in Artificial Intelligence, vol.156, pages 1-73, 2004.
Pizza Ontology, http://www.co-ode.org/ontologies/pizza/2007/02/12/
P.Doran. Ontology Reuse via Ontology Modularisation. In Proceedings of KnowledgeWeb PhD,
Symposium 2006 (KWEPSY2006). Budva, Montenegro. 17th June 2006.
Blomqvist, E.: State of the Art: Patterns in Ontology Engineering. Technical Report 04:8,
Jönköping University, November 2004.
WonderWeb, http://wonderWeb.semanticWeb.org/.
Zimmermann, A., Euzenat., J.Three semantics for distributed systems and their relations with
alignment composition. In Cruz, I., et al, eds, 5th Int.Semantic Web Conference, ISWC
2006,Athens, GA, USA, November 5-9, 2006, Proceedings, volume 4273 of Lecture Notes in
Computer Science, pages 16–29. Springer-Verlag GmbH, November 2006.
Euzenat., J., Zimmermann, A., Freitas, F. Alignment-based modules for encapsulating
ontologies, Proceedings of the Workshop on Modularization of Ontologies, Knowledge Capture
Conference, Banff, Canada, 2007.
Alex Borgida and Luciano Serafini. Distributed Description Logics: Directed domain
correspondences in federated information sources. In On the Move to Meaningful Internet
Systems 2002: CoopIS, DOA, and ODBASE : Confederated International Conferences CoopIS,
DOA, and ODBASE 2002, volume 2519 of LNCS. Springer, 2002.
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027595,http://www.neon-project.org/Web-content/.
Kaon2, http://kaon2.semanticWeb.org/.
Protégé, http://protege.stanford.edu/.
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