基于SAX模型的XML文档更新算法研究

XML作为交换资料的标准,广泛应用于分布式系统中,但是在使用XML DOM来处理大型XML文件时,会占用过多的存储器资源并需要更多的CPU时间。提出一种基于SAX模型的XML文档更新算法,利用SAX模型占用时间和空问少的优点进行文档的更新。形式化地定义了XML文档的更新脚本,使用X-Path来表示所更新的文档节点,在XML文档的SAX扫描过程中,生成XML文档的节点的X-Path,从而判断文档节点是否需要更新,然后通过将更新脚本应用到需更新文档实现文档更新。

Research of XML Document Updating Algorithm Based on SAX Model

The removal of heavy metals from sewage sludges is a problem that is exigent to be solved. Bioleaching is a new method for removing heavy metals from sewage sludges. It is considered to be an effective method with low costs and without causing secondary pollution. In this study, bioleaching method was applied to leach metals such as Cu, Zn, Mn, Cr and Cd contained in sewage sludges. Firstly, thiobacillus ferrooxidans (T.f) and thiobacillus thiooxidans (T.t) were obtained from a hot spring containing sulphur after a series of cultivating, separating and purifying. Then, the leach characteristics of T.f and T.t were investigated at different levels of substrate respectively and the influences of some basic factors such as substrate concentration, sludge concentration and initial pH on removal of heavy metals during bioleaching were studied. The results show that the efficiency of removing heavy metals of T.f is better than T.t and most of the heavy metals contained in sewage sludge can be effectively removed by T.f and T.t.