1. March 17, 2008SAC WT 20081 Hermes: a Semantic Web-Based News Decision Support System* Flavius Frasincar frasincar@few.eur.nl Erasmus University Rotterdam * Joint work with Jethro Borsje and Leonard Levering

2. March 17, 2008SAC WT 20082 Contents Motivation Hermes Framework: 1.News Classification 2.Query Formulation 3.Results Presentation Hermes News Portal: –An example Conclusions Future Work

3. March 17, 2008SAC WT 20083 Motivation Large quantity of news on the Web: –Difficult to find the ones of interest Limited annotation of RSS feeds: –Broad categories (business, cars, entertainment, etc.) News messages have a big impact on stock prices Google finance shows direct news which pertain to a certain portofolio: –Indirect news (competitors of Google like Microsoft are not presented) –Not possible to ask (time-related) queries about news

4. March 17, 2008SAC WT 20084 Hermes Framework Input: –News items from RSS feeds –Domain ontology linked to a semantic lexicon (e.g., WordNet) Output: –News items relevant for a particular user Three steps: –News Classification: Relate news items to ontology concepts –Query Formulation Allow the user to express his concepts of interest –Results Presentation Present the news items that match user’s concepts of interest

5. March 17, 2008SAC WT 20085 1. News Classification Concept defined in the ontology (class or individual) Multiple lexical representations for the same concept: –Ontology synonyms (e.g., New York → New York, Big Apple ) –Semantic lexicon synonyms (e.g., buy → acquire ) Concepts without subclasses or instances: –Semantic lexicon hyponyms (e.g., company → dot-com ) Lookup ontology concepts into news items Heuristics: at least three hits (concepts) in a news item Work in progress: use a word sense disambiguation algorithm (e.g., SSI, GAMBL)

6. March 17, 2008SAC WT 20086 1. News Classification The news classification process:

7. March 17, 2008SAC WT 20087 2. Query Formulation Present the domain knowledge as directed labeled multi- graph: –with the additional constraint that arcs between two nodes are not allowed to share the same label User selects the concepts of interest in the original graph (e.g., Google ) User is able to add to its selection concepts related to the concepts of interests via a certain relation (e.g., hasCompetitors : Microsoft, eBay, and Yahoo ) The selected concepts are presented in a separate graph (called search graph)

8. March 17, 2008SAC WT 20088 2. Query Formulation News are time stamped User is able to specify that only news in a certain time interval should be retrieved Time constraints: –Last hour –Last day –Last year –[2007-03-01T00:00:00.000+00:01, 2007-05- 31T00:00:00.000+00:01 ]

9. March 17, 2008SAC WT 20089 3. Results Presentation Return news items that match a query Present the concepts involved in the query Per each news items show a summary: –Title –Source –Date –Few lines from the news item Emphasize the hits (found concepts from the ontology) in the retrieved news items

10. March 17, 2008SAC WT 200810 Hermes News Portal Hermes News Portal (HNP) is an implementation of the Hermes framework Implementation language: Java Ontology represention langauge: OWL Semantic lexicon: WordNet Graph visualization: Prefuse Query language: SPARQL SPARQL extended with custom time functions (e.g., currentDate(), currentTime(), etc.)

11. March 17, 2008SAC WT 200811 An Example Query: Which are the news items interesting for Google from the past three months?

12. March 17, 2008SAC WT 200812 News Classification Conceptual graph:

13. March 17, 2008SAC WT 200813 2. Query Formulation Concepts selection:

14. March 17, 2008SAC WT 200814 2. Query Formulation Individuals Classes Selected concepts Concepts related to the selected node Concepts from keyword search Conceptual graph:

15. March 17, 2008SAC WT 200815 2. Query Formulation Search graph:

16. March 17, 2008SAC WT 200816 2. Query Formulation PREFIX hermes: SELECT ?title WHERE { ?news hermes:title ?title. ?news hermes:time ?date. ?news hermes:relation ?relation. ?relation hermes:relatedTo hermes:Google. FILTER ( ?date > "2007-03-01T00:00:00.000+00:01" && ?date < "2007-05-31T00:00:00.000+00:01" ) } SPARQL query:

17. March 17, 2008SAC WT 200817 2. Query Formulation Custom time functions: Function nameOutput type currentDate()xsd:date currentTimexsd:time now()xsd:dateTime dateTime-add(xsd:dateTime A, xsd:duration B)xsd:dateTime dateTime-substract(xsd:dateTime A, xsd:duration B)xsd:dateTime

18. March 17, 2008SAC WT 200818 2. Query Formulation PREFIX hermes: SELECT ?title WHERE { ?news hermes:title ?title. ?news hermes:time ?date. ?news hermes:relation ?relation. ?relation hermes:relatedTo hermes:Google. FILTER ( ?date > hermes:dateTime-substract(hermes:now(), P0Y3M) && ?date < hermes:now() ) } Extended SPARQL query:

19. March 17, 2008SAC WT 200819 3. Results Presentation

20. March 17, 2008SAC WT 200820 Conclusions Hermes Framework: presents news items that match the user interests Hermes Framework: –News Classification –Query Formulation –Results Presentation Hermes News Portal (HNP): an implementation of the Hera framework HNP based on: –WordNet semantic lexicon, OWL ontology, (extended) SPARQL queries, Prefuse visualization

21. March 17, 2008SAC WT 200821 Future Work Word Sense Disambiguation: –SSI –GAMBL Ontology updates: –Learning from news items –Check if the extracted information obeys the ontology axioms: Faulty extraction Ontology axioms update Simplify the query interface: –Allow users to ask English queries from a limited vocabulary Evaluate the tool outside the university lab