Gilles Falquet

Contextual ontologies: motivations, challenges, and solutions

Contextual ontologies are ontologies that characterize a concept by a set of properties that vary according to context. Contextual ontologies are now crucial for users who intend to exchange information in a domain. Existing ontology languages are not capable of defining such type of ontologies. The objective of this paper is to formally define a contextual ontology language to support the development of contextual ontologies. In this paper, we use description logics as an ontology language and then we extend it by introducing a new contextual constructor.

Concept Bases: A Support to Information Systems Integration

In this paper, we describe a technique for integrating heterogeneous information systems using concept bases. A concept base is build on top of each system to integrate, in order to semantically enrich its description. Each concept is described at three different levels: terminological definition, formal characterization, and representation in the underlying system. The different concept bases are then used to compare the concepts represented in the different systems and to establish correspondences between them in order to facilitate communication, cooperation, or integration. Our approach relies on results of the ConcepTerm project, dedicated to the study of concept dictionary building methodology and process. We also show that the building of a concept base can benefit database design and high-level interface definitions.

Ontologies in Urban Development Projects

Ontologies are increasingly recognized as essential tools in information science. Although the concepts are well understood theoretically , the practical implementation of ontologies remains challenging. In this book, researchers in computer science, information systems, ontology engineering, urban planning and design, civil and building engineering, and architecture present an interdisciplinary study of ontology engineering and its application in urban development projects. The first part of the book introduces the general notion of ontology, describing variations in abstraction level, coverage, and formality. It also discusses the use of ontologies to achieve interoperability, and to represent multiple points of view and multilingualism. This is illustrated with examples from the urban domain. The second part is specific to urban development. It covers spatial and geographical knowledge representation, the creation of urban ontologies from various knowledge sources, the interconnection of urban models and the interaction between standards and domain models. The third part presents case studies of the development of ontologies for urban mobility, urban morphological processes, road systems, and cultural heritage. Other cases report on the use of ontologies to solve urban development problems, in construction business models, building regulations and urban regeneration. It concludes with a discussion of key challenges for the future deployment of ontologies in this domain. This book bridges the gap between urban practitioners and computer scientists. As the essence of most urban projects lies in making connections between worldviews, ontology development has an important role to play, in promoting interoperability between data sources, both formal (urban databases, Building Integrated Models, Geographical Information Systems etc.) and less formal (thesauri, text records, web sources etc.). This volume offers a comprehensive introduction to ontology engineering for urban development. It is essential reading for practitioners and ontology designers working in urban development.

Combining Textual and Visual Ontologies to Solve Medical Multimodal Queries

In order to solve medical multimodal queries, we propose to split the queries in different dimensions using ontology. We extract both textual and visual terms depending on the ontology dimension they belong to. Based on these terms, we build different sub queries each corresponds to one query dimension. Then we use Boolean expressions on these sub queries to filter the entire document collection. The filtered document set is ranked using the techniques in vector space model. We also combine the ranked lists generated using both text and image indexes to further improve the retrieval performance. We have achieved the best overall performance for the medical image retrieval task in CLEF 2005. These experimental results show that while most queries are better handled by the text query processing as most semantic information are contained in the medical text cases, both textual and visual ontology dimensions are complementary in improving the results during media fusion

Conflict Resolution in the Collaborative Design of Terminological Knowledge Bases

Designing a terminological knowledge base consists in collecting terms and associating them to their definition. Our objective is to define a process model to support this design task in a collaborative work environment. The proposed concept model is based on terminological logic and the issue-based model IBIS. The terminological logic part is intended to formally express definitions and associate them to terms and points of view. The process model we define is based on a cyclic conflict resolution process. It includes a formal concept comparison operation, to highlight definition conflicts and their nature, and other operations (derivation, intersection, union, etc.) to solve the detected conflicts. The IBIS part of the model enable users to express and record issues, positions, arguments and endorsements that occur during conflict resolution.

Language and Tools to Specify Hypertext Views on Databases

We present a declarative language for the construction of hypertext views on databases. The language is based on an object-oriented data model and a simple hypertext model with reference and inclusion links. A hypertext view specification consists in a collection of parameterized node schemes which specify how to construct node and link instances from the database contents. We show how this language can express different issues in hypertext view design. These include: the direct mapping of objects to nodes; the construction of complex nodes based on sets of objects; the representation of polymorphic sets of objects; and the representation of tree and graph structures. We have defined sublanguages corresponding to particular database models (relational, semantic, object-oriented) and implemented tools to generate Web views for these database models.

Ontology Based Interfaces to Access a Library of Virtual Hyperbooks

A virtual hyperbook is a virtual document made of a set of information fragments linked to a domain ontology and equipped with selection and assembly methods or rules. In this paper, we study the problem of accessing and reading in a digital library of virtual hyperbooks. In this case it is necessary to generate hyperdocuments that present information and knowledge originating from several hyperbooks. Moreover, these hyper-documents must fit with the reading objectives or specific point of views of readers. Our approach is based on the integration of domain ontologies and the re-use of interface specifications.

An Ontology-based Model for Urban Planning Communication

Urban planning projects are complex and involve multiple actors ranging from urban planners to inhabitants. These actors differ greatly in their background or their centres of interest. The main objective of our research is various actors involved. With this intention, we defined an ontology-based model whose main characteristics are, on the one hand, the semantic integration in a knowledge base of the urban knowledge coming from various sources such as GIS databases, master plans, local plans or any other document and, on the other hand, the modelling of the centre of interest of an urban actor. This models can then be used to generate adapted user interfaces to present the interests.

Specifying the Representation of Non-geometric Information in 3D Virtual Environments

In 3D virtual environments (3DVE), we need to know what an object looks like (i.e. geometric information) and what the object is, what are its properties and characteristics and how it relates to other objects (i.e. non-geometric information). Several interactive presentation techniques have been devised to incorporate non-geometric information into 3DVEs. The relevance of a technique depends on the context. Therefore, the choice of an appropriate representation technique cannot be done once for all and must be adapted to the context. In this paper, we first present a preliminary classification of representation techniques for non-geometric information in 3DVE. Then we propose a formalism, based on description logics, to describe the usability of a technique in a given context. We show how these descriptions can be processed to select appropriate techniques when automatically or semi-automatically generating a 3DVE.

A Model for the Collaborative Design of Multi Point-of-View Terminological Knowledge Bases

Designing a terminological knowledge base consists in collecting terms and associating them to their definition. We present here a model that supports this design task in a collaborative environment. The proposed concept model is based on terminological logic and on the issue-based model IBIS. The terminological logic part is intended to formally express definitions and associate them to terms and points of view. It includes a formal concept comparison operation, to highlight definition conflicts and their nature, and other operations to solve the detected conflicts. The IBIS part of the model enable users to express and record issues, positions, arguments and endorsements that occur during conflict resolution.