An ever-growing number of XML-based languages are used to describe Web Service related issues such as security (WS-Security Policy), access control (XAC-ML), or privacy (P3P-WS). While it is desirable to specify policies in a declarative way, these languages expose great diversity in both syntax and semantics making it ...

The number of information sources in the Web is growing day by day with a tremendous speed. At the same time, users tend to manage more and more tasks electronically, thereby using publicly available information sources. Since the Web is an open, distributed and dynamic environment, in which information sources are offered ...