Fuzzy Sets and Fuzzy XML Data Models

Fuzzy information extensively exists in data and knowledge intensive applications, where fuzzy data play an import role in nature. Fuzzy set theory has been extensively applied to extend various database models and resulted in numerous contributions. On the other hand, XML (eXtensible Markup Language) has been the de facto standard. XML and related standards are technologies that allow the easy development of applications that exchange data over the Web. In this chapter, some notions of fuzzy set theory briefly introduced firstly. Then, we introduce fuzzy XML data models, specifically including: characteristics of XML, fuzzy data representations and classifications, fuzzy data in XML documents, fuzzy XML Schema definitions, and fuzzy XML DTD. Finally, we introduce fuzzy XML tree models.