Research On Semantic Preservation In Collaborative Editing Systems

Research on Computer-Supported collaborative editing systems is one of the most important domains in CSCW. In these systems, users can view and edit the same shared document at the same time, from geographically distributed sites connected by computers and network. Compared to Single-User editing systems, Multi-User collaborative editing systems have the benefit of improving efficiency, saving time and reducing cost. Currently, most of the researches are focused on syntactic consistency by ensuring convergence, causality and intention preservation, and works on semantic preservation are very limited. But semantic preservation problem shouldn't be ignored in collaborative editing systems, as every operation contains some user specific semantic, any misunderstanding for these semantic may cause conflict problem and thus hurt the efficiency of the collaborative work. Furthermore, semantic preservation can not be maintained by existing consistency maintenance algorithms, so it's necessary to research on the semantic preservation problems in collaborative editing systems.This paper focuses on the semantic preservation problems in collaborative editing systems, which is based on the newest research achievements in the world. The content includes: 1. According to different criterion, we classified the semantics in collaborative editing systems and analyze the characteristics of them, and then we proposed a new classification, by which we divides the semantics into four categories: description semantic, value constraint semantic, relation constraint semantic and personal semantic. 2. After the analysis for several semantic preservation models currently existing, we proposed a new semantic preservation model which is based on semantic library. In this model, every user semantic is described by semantic rule expression, which itself is described by SDL in semantic library files, so we can reload them next time. 3. We proposed three different methods for maintaining semantic library, include centralized maintenance, distributed maintenance and replicated maintenance, and also we discussed their principle and analyzed their characteristics. 4. Based on the replicated maintenance method, we proposed four suitable times for checking semantic confliction and an improved algorithm for inserting operation (includes normal operation and semantic operation) to solve the semantic conflict problem.At last, based on our CoDesign prototype system, we designed and implementeda semantic preservation subsystem which based on replicated semantic library, to test for the key technologies proposed in this paper.