中文摘要：

由于工程设计任务具有长期性、合作性、试探性和分布式性等特点,传统的事务模型和提交机制已经不能很好地满足工程设计任务的需要。针对工程设计任务的特点,提出了一种语义层次事务模型（SHTM）,SHTM采用了树形层次结构,并集成了事务的语义特征。同时,SHTM通过允许未提交事务借出它们持有的数据资源,放宽了事务的隔离性。在此基础上,进一步提出了能确保一致性数据操作的双层提交机制（DTCM）。DTCM综合事务的语义特征,很好地解决了放宽隔离性可能导致的不一致性情形。

英文摘要：

The traditional transaction model and commit mechanism cannot meet the requirement of engineering design tasks which possess the properties of long duration,cooperation,heuristic,distribution,etc.Aimed at the properties of engineering design tasks,a semantic hierarchy transaction model （called SHTM） was proposed.The SHTM adopts tree hierarchy structure and integrates semantic properties of transactions.At the same time,the SHTM relaxes the isolation property of transactions by allowing uncommitted transactions to lend their holding data.On the basis of it,the double-tier commit mechanism （called DTCM）,which can guarantee consistent data manipulation,was proposed.The DTCM synthesizes the semantic properties of transactions and solves the inconsistent cases,which can be caused by reason of relaxing the isolation property.