Pierre-Antoine Champin

Measuring the similarity of labeled graphs

This paper proposes a similarity measure to compare cases represented by labeled graphs. We first define an expressive model of directed labeled graph, allowing multiple labels on vertices and edges. Then we define the similarity problem as the search of a best mapping, where a mapping is a correspondence between vertices of the graphs. A key point of our approach is that this mapping does not have to be univalent, so that a vertex in a graph may be associated with several vertices of the other graph. Another key point is that the quality of the mapping is determined by generic functions, which can be tuned in order to implement domain-dependant knowledge. We discuss some computational issues related to this problem, and we describe a greedy algorithm for it. Finally, we show that our approach provides not only a quantitative measure of the similarity, but also qualitative information which can prove valuable in the adaptation phase of CBR.

SIOC in action representing the dynamics of online communities

SIOC --- Semantically-Interlinked Online Communities --- provides the Semantic Web with a vocabulary for representing activities and contributions of online communities. However, it focuses on the state of online communities at a given time, while a number of Web application put a strong emphasis on the dynamics of their components and users, including microblogging, status and geolocation notification, etc. and as also testified by recent efforts on modelling activity streams. This work proposes a new module for the SIOC vocabulary designed to represent the dynamics of actions within online communities. Hence, we provide an action-centric view of online communities, while previous work focused on a document-centric or user-centric one. Furthermore, we align our work with related vocabularies and Web technologies --- both in use and emerging --- inside and outside the field of Semantic Web technologies.

Cross: an OWL wrapper for reasoning on relational databases

One of the challenges of the Semantic Web is to integrate the huge amount of information already available on the standard Web, usually stored in relational databases. In this paper, we propose a formalization of a logic model of relational databases, and a transformation of that model into OWL, a Semantic Web language. This transformation is implemented in Cross, as an open-source prototype. We prove a relation between the notion of legal database state and the consistency of the corresponding OWL knowledge base. We then show how that transformation can prove useful to enhance databases, and integrate them in the Semantic Web.

Coping with noisy search experiences

The so-called Social Web has helped to change the very nature of the Internet by emphasising the role of our online experiences as new forms of content and service knowledge. In this paper we describe an approach to improving mainstream Web search by harnessing the search experiences of groups of like-minded searchers. We focus on the HeyStaks system (www.heystaks.com) and look in particular at the experiential knowledge that drives its search recommendations. Specifically we describe how this knowledge can be noisy, and we describe and evaluate a recommendation technique for coping with this noise and discuss how it may be incorporated into HeyStaks as a useful feature.

Canonical processes in active reading and hypervideo production

Active reading of audiovisual documents is an iterative activity, dedicated to the analysis of the audiovisual source through its enrichment with structured metadata and the definition of appropriate visualisation means for this metadata, producing new multimedia objects called hypervideos. We will describe in this article the general decomposition of active reading and how it is put into practice in the Advene framework, analysing how its activities fit into the Canonical Media Processes model.

A web-centric semantic mediation approach for spatial information systems

Semantics-related issues are at the heart of web-centric information systems and emerging spatial applications that require an integrated access to collections of heterogeneous data sources. We present an ontology-based semantic mediation approach and its application to spatial system interoperability. The approach is based on three contexts described by ontologies used to capture the semantics of data sources and to resolve their semantic discrepancies. The global ontology context defines generic application domain mediation concepts while the ontology local contexts are devoted to the description of local concepts. The cooperation contexts provide semantic concepts that encapsulate three key components: (1) semantic roles defined by ontological agreements on the global ontology, (2) virtual views defined on the local ontologies, and (3) context transformation mappings used to define inter-ontology relationships. We illustrate the proposed mediation approach on spatial information systems, relying on the description and reasoning capabilities of OWL to establish relations between concepts of the different ontologies.

Adding Epiphytic Assistance Systems in Learning Applications Using the SEPIA System

In this paper, we present how the SEPIA system can be used to plug pedagogical and technical assistance systems in applications used by learners in an educational context. The SEPIA system consists in two main tools: an assistance editor that enables assistance designers to specify the assistance they wish for existing applications, and a generic assistance engine that executes the specified assistance in order to provide the application end-users with personalized assistance. We also present an experimentation of an assistance system setup with SEPIA in the context of a bachelor degree.

Towards collaborative annotation for video accessibility

The ACAV project aims to explore how the accessibility of web videos can be improved by providing rich descriptions of video content in order to personalize the rendering of the content according to user sensory deficiencies. We present a motivating scenario, the results of a preliminary study as well as the different technologies that will be developed.

A Trace-Based Framework for supporting Digital Object Memories.

In this paper, we present a Trace Based framework for managing and transforming traces of observation and use of real life objects. Considering trace based systems as Digital Object Memories (DOMe), we describe how our frame-work can be used to manage DOMe, using trace models and transformations to raise the abstraction level of traces and infer useful knowledge. To demonstrate our approach, we present a simple example of smart home where the use and the state of some of everyday objects are observed, and the resulting traces of such observations are exploited as DOMe providing useful services.

Unified Access to Media Metadata on the Web

The goal of the World Wide Web Consortium (W3C) Media Annotation Working Group (MAWG) is to promote interoperability between multimedia metadata formats on the Web. Audio-visual data is omnipresent on todays Web, but different interaction interfaces and especially diverse metadata formats prevent unified search, access, and navigation. MAWG has addressed this issue by developing an interlingua ontology and an associated API. This article discusses the rationale and core concepts of the ontology and API for media resources. The specifications developed by MAWG enable interoperable, contextualized, and semantic annotation and search, independent of the source metadata format, that connects multimedia data to the Linked Data Cloud.