With the rapid development and spread of the Internet technology,there have been significant progresses inthe Internet information retrieval and active services. However,with the traditional Internet search engines and activeservices ,which are all based on simple similarity technology of features and users' personal information are matchingof keywords or bag of words ,the document described through simple key words or words bag,and documents featuresand users' personal interests aren't well depicted due to the lack of semantics. XML is a newly emerged standard forthe WWW data exchange and description. XML-based information retrieval system not only describes the contents ofthe documents,but also takes the documents' structural information. In this paper,a newer personal active informa-tion service system is discussed,under which the heterogeneous,distributed data spreading on the Web will be inte-grated to XML data,and users' personal information are described through XML queries. We have proposed the gen-eral architecture of this system,and several key technologies for the establishment of such a system are also pre-sented.
VHDL and its supporting environment are active domain in the field of logic design.In the paper the design principle and some key techniques to solve the problems on the implementation of the VHDL parser are introduced. According to the methods discussed in the paper, the VHDL parser based on VHDL IEEE 1076 standard version is implemented and a series of strict tests are done. This VHDL parser is front-end tool of the VHDL high level synthesis and mixed level simulation system developed by the Research Center of ASIC of BIT.
