1. Information Extractors Hassan A. Sleiman

2. Author Cuba Spain Lebanon

3. Presenting Gretel

4. Roadmap Introduction What is an IE? IE classification IE framework Conclusions

5. Roadmap Introduction What is an IE? IE classification IE framework Conclusions

6. We are talking about Wrapper Form Filler Navigator Information Extractor Ontologiser Verifier Endow data islands with APIs Ease implementing web agents

7. Look out! Wrappers are usually mistaken for information extractors.

8. The beginning DARPA Message Understanding Conferences (MUC).

9. Example Message ID: MUC-0001 Message Template:Court resolution Date of Event:April, 30 2007 Charge:Terrorist attack Person Charged:Salahuddin Amin Person Charged:Anthony Garcia Person Charged:Waheed Mahmood Person Charged: Omar Khyam … Message ID: MUC-0002 Message Template:News Date of Event:April, 30 2007 Date of Public.:April, 30 2007 Author:Jane Perlez Location:London Text:A British court… … …

10. Web has changed Increasing number Generated under user demand Telegraphic language HTML templates

11. Roadmap Introduction What is an IE system? IE classification IE framework Conclusions

12. What is an IE system? IE is the task of identifying the specific fragments of a single document that constitute its core semantic content. IE Systems rely on a set of extraction patterns that are used in order to retrieve relevant information from each document. “Muslea” “Kushmerick”

13. IE in action Input: Web pages Rules/patterns Output: Extracted data Extraction rules Information extractor Document Data The Da Vinci Code Dan Brown 15.95 € 2006 Robert Langdon… Doubleday

14. FormFiller + Navigator

15. Input document

16. Rules/Patterns/Grammar

17. Apply patterns

18. Extracted data

19. Input document

20. Rules/Patterns/Grammar

21. Apply patterns

22. Extracted data

23. keywords Learning processes Domain Rules Extraction algorithm

24. Roadmap Introduction What is an IE system? IE classification IE framework Conclusions

25. Our goals Compare IE techniques. A survey.

26. Classification Categories Input Algorithm Rules Efficiency and Effectiveness User interaction Other features Cat3 Cat1 CatN Cat2 Cat4

27. Input features Target pages: Free Text Semi-Structured Structured Target slots Page Record Tuple Attribute

28. Input features (2) Case target slots are Page, record or tuple: Multi-slot? Attribute permutation? Multi-formatted attributes? Pre Processing: Tidy POS tagging Zone detection Tokenisation.

29. Algorithm Degree of automation: Hand crafted Semi-Supervised Supervised Unsupervised Case of Supervised/Semi- supervised/Unsupervised: Number of input pages. Case of Supervised/Semi- supervised/Unsupervised: Tagging?

30. Algorithm (2) Algorithm type: Logic programming String alignment Tree alignment Clustering

31. Rules Fixed. XPointer Offset Based on Landmarks: Regular expressions Context-free grammars FOL (First Order Logic) FSA (Finite State Automata) Based on keywords Tree Patterns

32. Complexity Precision Recall Accuracy F-measure β Exist comparable results for the tool? Efficiency and Effectiveness

33. User interaction Target Audience : Developer Non-technical. Interface: API. Command Line. Configuration File. GUI.

34. Other features Commercialisation: Commercial Non Commercial URL Strong features Weak features

35. Roadmap Introduction What is an IE system? IE classification IE framework Conclusions

36. Idea IE framework. Reusable. Comparable results.

37. Identified parts

38. Identified parts (2)

39. Roadmap Introduction What is an IE? Our goals Conclusions

40. Conclusion Verifier Ontologiser Knowledge Base Extractor Information retrieval Ontology Dataset

41. Conclusions High degree of variability Inexistence of a comparative framework. Our goal: Reduce Comparing costs.

42. Thanks! Hassan A. Sleiman hassansleiman@us.es