Tayeb Lemlouma

Context-aware adaptation for mobile devices

This paper discusses the problem of content adaptation for mobile devices. The adaptation considers the context of the client and also the environment where the client request is received. A device independent model is defined and used in order to achieve automatic adaptation of the content based on its semantic and the capabilities of the target device. Our system includes a context description model and a client repository and offers device contexts management and querying functions. The proposed system uses the XQuery language to query the profiles and delivers the results in the form of SOAP services.

Adapted content delivery for different contexts

In this paper, we present a framework which allows adapted content delivery for different target contexts. This framework is based on a universal profiling schema, UPS, for describing the environment characteristics and on an profile exchange protocol. In the server and the proxy side, we give a strategy for matching the different constraints (clients, servers, content, etc.) in order to find an agreement between the server adaptation capabilities and the client preferences and constraints. Usually such environments are subject to frequent changes. To tackle this difficulty, we propose a dynamic adaptation approach based on XSLT for structural transformation and resource aware transcoders for media adaptation.

Encoding multimedia presentations for user preferences and limited environments

This paper discusses a new approach of generating TV-like multimedia presentations that are adapted to the target user preferences and to limited devices. Three main points are discussed: 1) the encoding of video presentations from a SMIL specification, 2) the adaptation of the video content based on the user preferences, and 3) the delivery of adapted multimedia presentations. The used architecture includes a content server, an adaptation proxy and a set of small devices in the form of personal device assistants (PDA). These devices request the content through a wireless network. In order to show how the system behaves regarding the user preferences and capabilities, two negotiation dimensions are considered: the user language and the memory capability of the device. The first dimension is used to generate a content that can be understood by the target user, e.g. a video with subtitles written in the preferred language. The second dimension is chosen to solve the problem of the system blocking that usually happens when limited devices access rich multimedia presentations over the network.

Content interaction and formatting for mobile devices

In this paper we present an experimental content adaptation system for mobile devices. The system enables the presentation of multimedia content and considers the problem of small screen display of mobile terminals. The approach combines structural and media adaptation with the content formatting and proposes a system that handles the user interaction and the content navigation.

NAC, une architecture pour l'adaptation multimédia sur le web

The web is evolving towards richer contents and diverse media that are accessed with different devices through multiple kinds of network. This heterogeneous, mobile and changing environment requires that multimedia information delivered by servers be adapted to the actual conditions of use. For that purpose, a number of methods, languages, formats and protocols are developed, especially by W3C. The NAC architecture presented in this article was designed and implemented based on these technologies, focusing on adaptation processing, on environment description models, on negotiation protocols, and on content transformations. MOTS-CLES : world wide web, multimedia, terminaux mobiles, adaptation, description de contexte, transformation.