On-demand late join for collaborative graphics editing systems in ubiquitous environment

It is important that a collaborative graphics editing system (CGES) allows a latecomer to join the collaborative editing session as soon as possible. In ubiquitous environment, a powerful workstation may most probably join and take the place of former server in order to take the advantage of the centralized architecture and make the collaborative editing more efficiently. We have developed a latecomer accommodation service and related late-join approach for such kind of latecomer in CGES with the centralized architecture. The presented on-demand input replica consistency approach and related object scheme ensure that only those input operations really needed for the latecomer are transmitted. The region that late joiner may be interested in are predicted. The needed partial input replica is migrated only when it is needed. The advantages of the proposed late-join approach are robustness, a low network load and a low initialization delay. The late-join approach is realized in our prototype system of collaborative graphics editing system that can work well in ubiquitous environments.