Catálogo de publicaciones - libros

The semantic web will not be a static collection of formats, data and meta-data but highly dynamic in each aspect. This paper proposes a personalized event notification system for semantic web documents (). The system can intelligently detect and filter changes in semantic web documents by exploiting the semantic structure of those documents. In our prototype, we combine the functionalities of user profiles and distributed authoring systems. Typically, both approaches would lack the ability to handle semantic web documents.

This paper introduces the design and implementation of our event notification system for semantic web documents that handles the XML representation of RDF. We analyzed our prototype regarding accuracy and efficiency in change detection. Our system supports sophisticated change detection including partial deletion, awareness for document restructuring, and approximate filter matches.

In this work, we present an Electronic Meeting Support system for handhelds. The design principles applied for developing the system are aimed to help reduce the problems associated with having a small size screen to interact with. The human-handheld interaction is based only in gestures and freehand writing, avoiding the need of widgets and virtual keyboards. The content of the generated documents are organized as concept maps, which gives more flexibility to reorganize and merge the contributions of the meeting attendees. Our system is based on handhelds interconnected with an ad-hoc wireless network. The system architecture is a peer-to-peer one, avoiding the need of central repositories thus allowing meetings to take place anywhere.

Welcome to the Fifth International Conference on Ontologies, Databases, and Applications of Semantics (ODBASE 2006). This year’s ODBASE conference was held in Montpellier, France from October 29 to November 3, 2006.

The ODBASE conferences provide a forum for exchanging the latest research results on ontologies, data semantics, and other areas of computing related to the Semantic Web. We encourage participation of both researchers and practitioners in order to facilitate exchange of ideas and results on semantic issues in Web information systems. Towards this goal, we accepted both research and experience papers.

In this invited talk, we present the SomeWhere approach and infrastructure for building semantic peer-to-peer data management systems based on simple personalized ontologies distributed at a large scale. Somewhere is based on a simple class-based data model in which the data is a set of resource identifiers (e.g., URIs), the schemas are (simple) definitions of classes possibly constrained by inclusion, disjunction or equivalence statements, and mappings are inclusion, disjunction or equivalence statements between classes of different peer ontologies. In this setting, query answering over peers can be done by distributed query rewriting, which can be equivalently reduced to distributed consequence finding in propositional logic. It is done by using the message-passing distributed algorithm that we have implemented for consequence finding of a clause w.r.t a set of distributed propositional theories. We summarize its main properties (soundness, completeness and termination), and we report experiments showing that it already scales up to a thousand of peers. Finally, we mention ongoing work on extending the current data model to RDF(S) and on handling possible inconsistencies between the ontologies of different peers.

Nowadays, ontologies are used in several research domains by offering the means to describe and represent concepts of information sources. Therefore, several approaches and systems storing ontologies and their instances in the same repository (database) have been proposed. As a consequence, defining a query language to support ontology-based database (OBDB) becomes a challenge for the database community. In this paper, we present , an ontology query language for OBDBs. Firstly, we present formally the OBDB data model supported by this language. Secondly, an overview of the algebra defining the semantics of operators used in is described. Several query examples showing the interest of this language compared to traditional database query languages are given along this paper. Finally, we present a prototype of the implementation of .

Various data sources on the Web tend to be highly dynamic; this is evident in prominent Web services frameworks in which devices register or deregister their descriptions quite rapidly and in Semantic Web portals which allow content authors to modify or extend underlying ontologies and submit content. Such applications often leverage Description Logic (DL) reasoning for a variety of tasks (e.g., classifying Web service descriptions, etc); however, this can introduce substantial overhead due to content fluctuation, as DL reasoners have only been considered for relatively static knowledge bases. This work aims to provide more efficient DL reasoning techniques for frequently changing instance bases (ABoxes). More specifically, we investigate the process of incrementally updating tableau completion graphs used for reasoning in the expressive DLs and , which correspond to a large subset of the W3C standard Web Ontology Language, OWL-DL. We present an algorithm for updating completion graphs under the syntactic addition and removal of ABox assertions. We also provide an empirical analysis of the approach through an implementation in the OWL-DL reasoner, Pellet.

Ontologies are instruments for capturing and using formal semantics, and are often the result of a ”central committee controlled” style of working. A new trend on the Web is the increasing popularity of folksologies in the form of social bookmarking sites. Folksologies provide informal semantics and can be created and adopted by anybody anytime anywhere on the Internet. Shared meaning in a folksology emerges through the use of tags that are used to bookmark web pages, their usage frequency being considered a reliable indicator of their usefulness and acceptance.

Rather than choosing for either ontologies or folksologies, hybrid emergent semantics systems are needed that combine elements of both perspectives, depending on the particular application. There is a need to analyse the larger picture (including the full range of semantics’ functionalities in their context of use.

In this paper, we outline a number of key design characteristics of emergent semantics systems (ESS). We examine the functionalities of two existing examples of well-known ESSs: del.icio.us and Piggy Bank. Using the results of this comparison, we introduce DogmaBank as a proof of concept implementation of a next-generation ESS that introduces a more advanced combination of lexical and conceptual emergent semantics functionalities.

Workflow management systems usually interpret a workflow definition rigidly, allowing no deviations during execution. However, there are real life situations where users should be allowed to deviate from the prescribed static workflow definition for various reasons, including lack of information about parameter values and unavailability of the required resources. To flexibilize workflow execution, this paper proposes an exception handling mechanism that allows the execution to proceed when otherwise it would have been stopped. The proposal is introduced as a set of extensions to OWL-S that capture the information required for the flexibilization mechanism. In particular, this paper focus on the transactional behavior of a workflow instance, in the sense that it guarantees that either all actions executed by the instance terminate correctly or they are all abandoned.

An important goal of a content management system (CMS) is to acquire and organise content from different data sources in order to answer intelligently any ad-hoc requests from users as well as from peer systems. Existing commercial CMSs address this issue by deploying structured metadata (e.g. XML) to categorise content and produce search indices. Unfortunately, these metadata are not expressive enough to represent content for sophisticated searching. This paper presents an open architecture framework and a Java-based reference implementation for Ontology-enabled Content Management System. The reference implementation uses an open-source CMS called OpenCMS, the Protégé’s OWL library, and RacerPro reasoning engine. The implemented system is a web-based management system for learning objects which were derived from the course and instructional materials used in several postgraduate taught courses. We believe that our OeCMS architecture and implementation would provide a strong platform for developing semantic web protals in general.

Large amounts of data in modern information systems, such as the World Wide Web, require innovative information retrieval techniques to effectively satisfy users’ information need. A promising approach is to exploit document semantics in the IR process. For this purpose, high-quality semantic metadata is needed. This paper introduces a method to automatically create semantic metadata by using ontologically enhanced versions of common information extraction methods, such as named entity recognition and coreference resolution. Furthermore, this work also proposes the application of ontology-specific heuristic rules to further improve the quality of generated metadata. The results of our method was evaluated using a small test collection.