A General Framework for Representing, Reasoning and Querying with Annotated Semantic Web Data

We describe a generic framework for representing and reasoning with annotated Semantic Web data, a task becoming more important with the recent increased amount of inconsistent and non-reliable meta-data on the web. We formalise the annotated language, the corresponding deductive system and address the query answering problem. Previous contributions on specific RDF annotation domains are encompassed by our unified reasoning formalism as we show by instantiating it on (i) temporal, (ii) fuzzy, and (iii) provenance annotations. Moreover, we provide a generic method for combining multiple annotation domains allowing to represent, e.g. temporally-annotated fuzzy RDF. Furthermore, we address the development of a query language -- AnQL -- that is inspired by SPARQL, including several features of SPARQL 1.1 (subqueries, aggregates, assignment, solution modifiers) along with the formal definitions of their semantics

Reengineering the Core Grid Ontology

http://ceur-ws.org/Vol-918/111110298.pdfInternational audienceOntology engineering is a relatively new and immature science. With new pos- sible applications and often non-normative standard proposals emerging rapidly it is hard to nd one universal formalization of ontology engineering rules. This causes many authors to fall into a trap of focusing on the application of an ontology and not giving enough attention to the ontology itself. Such approach results in ontologies that are hardly reusable, overcomplicated and di cult to understand which is the exact opposite of what a good ontology should be. While many problems are very speci c we attempt to bring the attention to a set of common ones with the intention of instructing how to x or avoid them. Here, we explain how we improved an existing ontology, Core Grid Ontology (CGO), that we use as an example. It is not our intention to focus on the quality of this ontology, which otherwise ts our needs well. Indeed, CGO was reused in the project Agents in Grid (AiG), where it was slightly modi ed then extended [1]. We build on that experience, starting with the reengineering of CGO that we will later extend with the improvements of the AiG ontology

Conflict resolution when axioms are materialized in semantic-based smart environments.

International audienceIn SemanticWeb applications, reasoning engines that are data intensive commonly materialise inferences to speed up processing at query time. However, in evolving systems, such as smart environments, semantic-based context aware systems (SCAS) [6] or social software with user-generated data, knowledge does not grow monotonically: newer facts may contradict older ones, knowledge may be deprecated, discarded or updated such that knowledge must sometimes be retracted. We are describing a technique to retract explicit and inferred statements, when some information becomes obsolete, as well as retracting any statement that would lead to get back the removed explicit statements. This technique is based on OWL justifications and is triggered whenever a knowledge base becomes inconsistent, such that the system stays in a consistent state all the time, in spite of uncontrolled evolution.We prove termination and correctness of the algorithm, and describe the implementation and evaluation of the proposal

Smart City Artifacts Web Portal

International audienceIn the smart city domain, many projects and works are generating essential information. Open and efficient sharing of this information can be beneficial for all parties ranging from researchers, engineers or even governments. To our knowledge, there is currently no full-fledged semantic platform which properly models this domain, publishes such information and allows data extraction using a standard query language. To complement this, we developed and deployed the Smart City Artifacts web portal. In this paper, we present our approach used within this platform and summaries some of its technical features and applications

Integrated distributed description logics

zimmermann2007aInternational audienceWe propose a Description-Logics-based language that extends standard DL with distributed capabilities. More precisely, it offers the possibility to formally describe the semantic relations that exist between two ontologies in a networked knowledge-based system. Contrary to Distributed Description Logics, it is possible to compose correspondences (or bridge rules), while still being able to hide some of the discrepancies between ontologies. Moreover, when ontologies have no nominals, no A-Box axioms, and correspondences are restricted to cross-ontology subsumption, the satisfiability of a local ontology is not influenced by ontology alignments and other ontologies, i.e., local deduction is invariant to the change of the outer system. Although we do not have a complete reasoning procedure, we provide inference rules and semantic properties, and a discussion on reasoning in this formalism

Nell2RDF: Read the Web, and turn it into RDF

http://www.ke.tu-darmstadt.de/know-a-lod-2013/wp-content/uploads/2013/05/know@lod_2.pdfInternational audienceThis paper describes the Nell2RDF platform that provides Linked Data of general knowledge, based on data automatically constructed by a permanent machine learning process called NELL that reads the Web. As opposed to DBpedia, all facts recorded by NELL can be tracked according to its provenance and a degree of confidence. With our platform, we aim at capturing all the data generated by NELL a transform them into state of the art Linked Data, following best practices. We discuss the benefits of the platform in opening new lines of research, while the work is still in progress

Applying semantic web technologies to context modeling in ambient intelligence

http://www.emse.fr/~picard/publications/sorici13percam.pdfInternational audienceRepresentation and reasoning about context information is a main area of research in Ambient Intelligence (AmI). Given the openness and decentralization of many AmI applications, we argue that usage of se- mantic web technologies for context modeling brings advantages in terms of standards, uniform representation and expressive reasoning. We present an approach for modeling of context information which builds and improves upon related lines of work (SOUPA, CML, annotated RDF). We provide a formalization of the model and an innovative realization using the latest proposals for semantic web standards like RDF and SPARQL. A commonly encountered ambient intelligence scenario showcases the approach

Provenance for SPARQL queries

Determining trust of data available in the Semantic Web is fundamental for applications and users, in particular for linked open data obtained from SPARQL endpoints. There exist several proposals in the literature to annotate SPARQL query results with values from abstract models, adapting the seminal works on provenance for annotated relational databases. We provide an approach capable of providing provenance information for a large and significant fragment of SPARQL 1.1, including for the first time the major non-monotonic constructs under multiset semantics. The approach is based on the translation of SPARQL into relational queries over annotated relations with values of the most general m-semiring, and in this way also refuting a claim in the literature that the OPTIONAL construct of SPARQL cannot be captured appropriately with the known abstract models.Comment: 22 pages, extended version of the ISWC 2012 paper including proof

Integrating Semantic Web technologies and Multi-Agent Systems: a Semantic Description of Multi-Agent Organizations

http://ceur-ws.org/Vol-918/111110296.pdfInternational audienceDecentralization and openness are inherent properties of multi- agent systems (MAS). The technologies they provide are thus the right abstrac- tion for developing Web-oriented applications. Moreover, di erent works have been proposed to use Semantic Web technologies (SWT) for representing vari- ous dimensions of MAS (e.g., interaction protocols, norms, organizations). Given these facts, we think it is time to go a step further by integrating SWT and MAS in order to improve reusability of data, knowledge, coordination strategies, etc. on the Web and across systems. In this paper, we take a rst step in this direc- tion by proposing a semantic description of multi-agent organizations, showing the bene t regarding integration with Web ontologies