中文摘要：

作为一类高级分布式系统,实时协同编辑系统允许不同地点的用户同时编辑共享文档,具有高响应性和高并发性的特点.操作转换（Operational Transformation,OT）算法能够保留所有用户操作的效果并维护数据的一致性,是协同编辑系统首选的并发控制方法.为了提高远程操作的响应时间,文中提出了一种意图保持的OT算法（Merging Operations based Operational Transformation,MOOT）.该算法基于这样一个事实,大多数情况下,协同编辑中插入操作的数量明显多于删除操作.因此,MOOT构造了一种优化的操作历史结构,即删除操作排在插入操作前面,避免算法的计算时间依赖于大多数操作.更进一步,MOOT在重构过程中移除无效操作,有效的压缩了操作历史的大小.为了验证算法的有效性,在不同插入比例情况下,将MOOT算法与当前性能最优的ABT算法进行了对比实验.实验结果表明,MOOT算法具有更高的计算效率,在合理的比例情况下,其计算时间大约是ABT算法的计算时间的十分之一.

英文摘要：

As a kind of advanced distributed systems,real-time collaborative editing systems allow geographically dispersed users to manipulate the shared document simultaneously with the characteristic of high concurrency and responsiveness.Operational Transformation（OT）algorithm,which is able to preserve the operation effects of all collaborators and maintain the data consistency,is the concurrency control method of first choice for collaborative editing systems.To improve the response time of remote operations,this paper proposes an OT algorithm with preserving intention（Merging Operations based Operational Transformation,shorted as MOOT）.The idea comes from the fact that the number of insertions is obviously more than that of deletions in collaborative editing environment.The MOOT algorithm constructed an optimized operation history with deletions before insertions so that the computing time did not depend on the majority of operations.Moreover,the algorithm removed useless operations,which effectively compressed the size of the operation history.To confirm the algorithm＇s effectiveness,this paper conducted experiments comparing the performance of MOOT with the state of the art algorithm（ABT）indifferent ratios of insertions.As shown by the experiments,MOOT algorithm is more efficient than ABT algorithm.In a reasonable percentage（80%）,the proposed method computes approximately 10 times faster than ABT algorithm.