Query interpretation to help peers understand each others in semantically heterogeneous systems

National audienceIn semantic web applications where query initiators and information providers do not necessarily share the same ontology, semantic interoperability generally relies on ontology matching or schema mappings. Information exchange is then not only enabled by the established correspondences (the ``shared'' parts of the ontologies) but, in some sense, limited to them. Then, how the ``unshared'' parts can also contribute to and improve information exchange ? In this paper, we address this question by considering a system where documents and queries are represented by semantic vectors. We propose a specific query expansion step at the query initiator's side and a query interpretation step at the document provider's. Through these steps, unshared concepts contribute to evaluate the relevance of documents wrt. a given query. Our experiments show an important improvement of retrieval relevance when concepts of documents and queries are not shared. Even if the concepts of the initial query are not shared by the document provider, our method still ensures 90% of the precision and recall obtained when the concepts are shared

Echange d'Information grâce à des caractérisations sémantiques

National audienceUsing ontologies allows agents to put meaning behind the terms appearing in the information exchanges. Supporting us on this fact, we propose an entity named focus allowing to represent various kinds of information contents : documents, data bases, services, agents' capabilities, etc. A focus consists of a weighting of the concepts of an ontology in order to indicate which meanings are important for the agent which has set it up. To help the capture of the values in the focus we present a procedure to spread the weightings in the focus. Then we define a measure of relevance of a focus compared to another. The originality of our approach lies in the fact that the focus is an exchangeable entity between the agents and does not require a centralization of the data collections

Improving Interoperability Using Query Interpretation in Semantic Vector Spaces

International audienceIn semantic web applications where query initiators and information providers do not necessarily share the same ontology, semantic interoperability generally relies on ontology matching or schema mappings. Information exchange is then not only enabled by the established correspondences (the ``shared'' parts of the ontologies) but, in some sense, limited to them. Then, how the ``unshared'' parts can also contribute to and improve information exchange ? In this paper, we address this question by considering a system where documents and queries are represented by semantic vectors. We propose a specific query expansion step at the query initiator's side and a query interpretation step at the document provider's. Through these steps, unshared concepts contribute to evaluate the relevance of documents wrt. a given query. Our experiments show an important improvement of retrieval relevance when concepts of documents and queries are not shared. Even if the concepts of the initial query are not shared by the document provider, our method still ensures 90% of the precision and recall obtained when the concepts are shared

A Framework to Assess Knowledge Graphs Accountability

Knowledge Graphs (KGs), and Linked Open Data in particular, enable the generation and exchange of more and more information on the Web. In order to use and reuse these data properly, the presence of accountability information is essential. Accountability requires specific and accurate information about people's responsibilities and actions. In this article, we define KGAcc, a framework dedicated to the assessment of RDF graphs accountability. It consists of accountability requirements and a measure of accountability for KGs. Then, we evaluate KGs from the LOD cloud and describe the results obtained. Finally, we compare our approach with data quality and FAIR assessment frameworks to highlight the differences.Comment: 8 pages, to be published in: 2023 IEEE International Conference on Web Intelligence and Intelligent Agent Technology (WI-IAT

Représentation optimiste de contenus dans les système P2P

International audienceNous nous intéressons aux systèmes distribués et hétérogènes disposant de nombreuses sources d'information autonomes, tels que les systèmes pair-à-pair non structurés. Dans de tels systèmes, le routage des requêtes, en particulier les requêtes top-k, est souvent limité à des algorithmes simples proches des parcours en largeur ou en profondeur, tels le flooding. Des améliorations utilisant des processus de gossiping ou des historiques des requêtes passées ont été proposées. Cependant, ils restent gourmands en envois de messages et ne garantissent pas d'obtenir les meilleurs résultats. En effet, ils ne disposent pas d'une représentation des sources leur permettant de décider a priori si l'envoi d'une requête est inutile. Dans ce but, nous définissons la propriété d'optimisme de l'évaluation d'une représentation d'une source par rapport à une mesure de pertinence : celle-ci, pour une requête donnée, évalue toujours la représentation d'une source avec une valeur supérieure ou égale à celle qu'aurait n'importe quelle information accessible via cette source, à une distance donnée. Dans un premier temps, nous motivons l'utilité d'une telle représentation sur des exemples. Nous proposons ensuite une analyse des propriétés nécessaires à la représentation d'un ensemble de documents pour l'usage visé. Puis, dans le cas de documents représentés par des vecteurs sémantiques, nous définissons (i) une agrégation incrémentale et composable et (ii) une représentation optimiste par rapport à une mesure de pertinence basée sur le cosinus

Dealing with P2P semantic heterogeneity through query expansion and interpretation

International audienceIn P2P systems where query initiators and information providers do not necessarily share the same ontology, semantic interoperability generally relies on ontology matching or schema mappings. Information exchange is then not only enabled by the established correspondences (the "shared" parts of the ontologies) but, in some sense, limited to them. Then, to what extent the "unshared" parts can also contribute to and improve information exchange? In this paper, we address this question by considering a system where documents and queries are represented by semantic vectors. We propose a specific query expansion step at the query initiator's side and a query interpretation step at the document provider's. Through these steps, unshared concepts contribute to evaluate the relevance of documents wrt. a given query. Our experiments show that our method enables to correctly evaluate the relevance of a document even if concepts of a query are not shared. In some cases, we are able to find up to 90% of the documents that would be selected when all the central concepts are shared

Multiphase Flow LES Study of the Fuel Split Effects on Combustion Instabilities in an Ultra Low-NOx Annular Combustor

International audienceThis paper describes the application of a coupled acoustic model/large-eddy simulation approach to assess the effect of fuel split on combustion instabilities in an industrial ultra-low-NOx annular combustor. Multiphase flow LES and an analytical model (analytical tool to analyze and control azimuthal modes in annular chambers (ATACAMAC)) to predict thermoacoustic modes are combined to reveal and compare two mechanisms leading to thermoacoustic instabilities: (1) a gaseous type in the multipoint zone (MPZ) where acoustics generates vortex shedding, which then wrinkle the flame front, and (2) a multiphase flow type in the pilot zone (PZ) where acoustics can modify the liquid fuel transport and the evaporation process leading to gaseous fuel oscillations. The aim of this paper is to investigate these mechanisms by changing the fuel split (from 5% to 20%, mainly affecting the PZ and mechanism 2) to assess which mechanism controls the flame dynamics. First, the eigenmodes of the annular chamber are investigated using an analytical model validated by 3D Helmholtz simulations. Then, multiphase flow LES are forced at the eigenfrequencies of the chamber for three different fuel split values. Key features of the flow and flame dynamics are investigated. Results show that acoustic forcing generates gaseous fuel oscillations in the PZ, which strongly depend on the fuel split parameter. However, the correlation between acoustics and the global (pilot + multipoint) heat release fluctuations highlights no dependency on the fuel split staging. It suggests that vortex shedding in the MPZ, almost not depending on the fuel split, is the main feature controlling the flame dynamics for this engin

Query Expansion and Interpretation to Go Beyond Semantic P2P Interoperability

International audienceIn P2P data management systems, semantic interoperability between any two peers that do not share the same ontology relyes on ontology matching. The established correspondences, i.e. the “shared” parts of the ontologies are indeed essential to exchange information. But to what extent the “unshared” part can contribute to information exchange. In this paper, we address this question. We focus on a P2P document management system, where documents and queries are represented by semantic vectors. We propose a specific query expansion step at the query initiator's side and a query interpretation step at the document provider's. Through these steps, unshared concepts contribute to evaluate the relevance of documents wrt a given query. The experiments show that the proposed method enables to correctly evaluate the relevance of a document even if concepts of a query are not shared. In some cases, we are able to find up to 90% of the documents that would be selected when all the concepts are shared

A Satisfaction Balanced Query Allocation Process for Distributed Information Systems

National audienceWe consider a distributed information system that allows autonomous consumers to query autonomous providers. We focus on the problem of query allocation from a new point of view, by considering consumers and providers' satisfaction in addition to query load. We define satisfaction as a long-run notion based on the consumers and providers' intentions. Intuitively, a participant should obtain good satisfaction as far as it (the participant) is adequate to the system. We propose and validate a mediation process, called SBMediation, which is compared to CapacityBased query allocation. The experimental results show that SBMediation significantly outperforms CapacityBased when confronted to autonomous participants

Personalization through query explanation and document adaptation

International audienceWe present a new formal approach to retrieval personaliza- tion which emcompasses a query personalization process at the user's side with a light document adaptation at the in- formation server's side. Our solution relies on the use of a domain ontology: queries and documents are in fact indexed by sets of concepts. For each concept of the query, the query personalization process allows to express the importance of linked concepts, which may vary according to the search con- text. Each query concept can be ”clarified” by this process; although the proposed method clarifies only central query concepts. The initial query as well as its defined clarifica- tions are sent to the server. Then, the server reconsiders its document representations based on both the query and the concepts clarifications it received. The proposed solution does not require that the information server maintains any user profile, and can be useful when, for privacy concerns, it is committed not to profiling the users