ABSTRACT
Today’s Web has millions of pages that are dynamically generated from content stored in databases. This not only makes managing a large site easier but also helps organize both Web-based user collaborations and content generation. These local databases, in one sense, are not full participants
on the Web. Though they drive the presentation of Web sites, the databases themselves are not interconnected in the linked manner that traditional static Web sites are. Should a mashup be desired, one organization has no obvious online way of using or understanding another’s data except through the human-readable presentation on a Web site. If these organizations want to share or merge information, any required
11.1 Introduction ..................................................................................................................................................................... 231 11.2 What Is the Semantic Web? ............................................................................................................................................. 232 11.3 Vocabularies and Ontologies ........................................................................................................................................... 232 11.4 Linked Data ..................................................................................................................................................................... 233 11.5 Motivations ...................................................................................................................................................................... 233
11.5.1 Content Mashup ................................................................................................................................................... 233 11.5.2 Semantic Search .................................................................................................................................................. 234 11.5.3 Provenance ........................................................................................................................................................... 234 11.5.4 Ubiquitous Computing ......................................................................................................................................... 234
11.6 Semantic Web Example ................................................................................................................................................... 234 11.7 Encoding Information on the Semantic Web .................................................................................................................. 236
11.7.1 RDF and RDFS .................................................................................................................................................... 236 11.7.1.1 Document Skeleton ............................................................................................................................... 236 11.7.1.2 De£ning Vocabularies .......................................................................................................................... 237 11.7.1.3 Describing Classes ................................................................................................................................ 237 11.7.1.4 Describing Properties ........................................................................................................................... 237
11.7.2 Creating Instances ............................................................................................................................................... 238 11.7.3 OWL .................................................................................................................................................................... 238
11.8 Querying Semantic Web Data through SPARQL ............................................................................................................ 240 11.9 Tools for Creating Semantic Web Markup ...................................................................................................................... 240
11.9.1 Ontology Editors .................................................................................................................................................. 240 11.9.2 Semantic Wikis .................................................................................................................................................... 240
11.10 Case Study: https://Data-gov.tw.rpi.edu .......................................................................................................................... 241 11.10.1 Background ........................................................................................................................................................ 241 11.10.2 The Data-gov Wiki ............................................................................................................................................ 241 11.10.3 Conversion Phase ............................................................................................................................................... 242 11.10.4 Publication Phase ............................................................................................................................................... 242 11.10.5 Linking Phase .................................................................................................................................................... 242 11.10.6 Web Development through the Data-gov Wiki ................................................................................................. 243
11.11 Conclusion ...................................................................................................................................................................... 246 Acknowledgments ..................................................................................................................................................................... 246 References ................................................................................................................................................................................. 246
database integration can be a signi£cant undertaking. It is also a one-time solution. That is, if a third organization entered the picture, a new merging effort would have to be undertaken.
