城市地下管线的隐蔽性、动态性、网络性和多样性决定了地下管线信息管理与信息系统开发的复杂性与难度。本文给出了一种城市综合信息系统开发模式，很好地解决了数据的可靠性和精度、数据的动态更新等难题，并对信息系统设计进行了较详细的描述。该模式对大中城市综合地下管线系统的建设具有很好的借鉴和指导意义。

为解决事务处理中的数据并发访问问题，该文提出了一种基于内存快照的加锁机制，并研究了这种机制在传统事务中的应用；此外，还探讨了快照机制在解决实时数据库系统的事务执行期限问题和全回卷问题等方面的应用。

We propose a new tree similarit measure based on the Connectivity-lntegrality Principle (CI). C! is a concept from graph theory that makes the tree similarity to be measured by taking account of both the partial and the integral structures of trees. We have proved in theory that the new measure has better flexibility than the other lavo typical similarity measures when given a variety of common substructures benveen two trees. We apply this new measure to a specific-domain QA system to undertake the task of sentencelevel disambiguation. Experimental results show that, the new model can effectively enhance the rejection rate that aims at irrelevant documents