1. Semantic Search Jiawei Rong 2005.11.30

2. Authors Semantic Search, in Proc. Of WWW 2003. Author R. Guhua (IBM) Rob McCool (Stanford University) Eric Miller (www.w3.org)

3. Semantic Web Definition Semantic Web is the idea of having data on the web defined and linked in a way that it can be used for more effective discovery, automation, integration, and reuse across various applications. Resource Relation

4. Semantic Web Model Directed labeled graph Nodes: Resources Arcs: Property Type

5. Semantic Web vs. Current Web Documents vs. Real World Objects Human vs. Machine Readable Info HTML vs. Semantic Web Distributed Extensibility

6. Semantic Search Introduction Navigational Search --The user provides the search engine a phrase or combination of words which are expected to be found in the documents. No interpretation. Research Search --The user provides a phrase which is intended to denote an object about which the user is trying to gather information.

7. Semantic Search Goals Augment traditional search results with data pulled from the Semantic Web Use an understanding of the denotation of the search term to improve traditional search

8. TAP TAP (Stanford University) An infrastructure for the applications on the Semantic Web For sites to publish data onto Semantic Web For applications to consume the data through query interface called GetData

9. GetData query interface GetData(, )=> Examples GetData(, birthplace)=> GetData(, temperature)=>57F GetData(, livesIn)=> Search: returns all the resources whose properties contain the query string Reflection: Given a node, returns the arcs going in and out of the node

10. TAP Publish, Registry and Cach TAPache Creates a directory and places RDF files in it. The URL associated with each graph is that of the file. Registry A separate server to keep track of what graph has the values for which properties about which resources. Caching Cache the responses to GetData Requests

11. Data Source Activity Based Search (ABS) Musicians, athletes, actors, places, products W3C Semantic Search People, W3C activities, working groups and other committees, documents and news

12. System Architecture Choose a denotation Map the search term to one or more nodes of the Semantic Web Determine what to show What data to show and in what order Format Display the results in a user interface

13. Choosing a Denotation Ambiguity Solution Pick the denotation according to the popularity of the term Or according to the user profile Or according to the search context Complex Search Term Solution Restrict complex search terms to only two denotations

14. Determining what to show Method 1 Breadth first order search with heuristics rules such as include at most N triples with the same source and same arc label or include at most M triples with the same source. Method 2 For each class or object, the set of pre-defined properties are manually specified Hybrid

15. Formatting

16. Semantics for Text Search Enable a search engine to understand that different occurrences of the same string denote different things Filter and rank the results to show the documents referring to the chosen denotation

17. Heuristics Knowing the user is searching for a person The type of the person General knowledge about the person, like e-mail address

18. Conclusion Two mechanisms Augment the search results Provide denotation to the search Future Work Help the text search system to exploit a deeper understanding of the search term’s denotation

19. Thank you!