Préservation des Intentions et Maintien de la Cohérence des Données Répliquées en Temps Réel. (Intention Preservation and Consistency Maintenance for Real-Time Replicated Data)

Real-time collaborative editors, like GoogleDocs or Etherpad, allow the simultaneous edition of adocument by several users. These applications need to replicate the edited document, for the so calledreal-time purpose of permitting a fast and reactive editing by any user at any time. Editing conflictsfrequently occur, and must be automatically handled by the application, in order to provide every userswith the same copy of the document, containing every modifications issued.Most of current real-time collaborative editing algorithms were designed for simple data structures,like linear text, and simple editing ways, like inserting or removing a character only. These algorithmsfail to offer an appropriate editing conflict resolution when used with a complex data structure, likeXML, or with complex operations, like moving some text or adding some style. Copies are the sames butusers’ intentions are not preserved. The goal of this thesis is to design new real-time collaborative editingalgorithms that ensure a better preservation of users’ intentions.The first contribution of this thesis is an algorithm based on the Operational Transformation approach(OT). Our contribution is designed to handle rich text document (with stylized text and paragraphs) andto preserve the intentions of a set of high editing level operations (add style, merge paragraphs...). Thiscontribution has lead to an industrial transfer for our industrial partner.The second contribution uses the Commutative Replicated Data Types approach (CRDT), and offersan algorithm which preserves the update intention, while improving global performance of the approachwhen dealing with large blocs of data. This contribution has lead to a web real-time collaborative editingapplication developed by our research team, currently available and in continuous improvement.