1. An Ontology-Based Method for Extracting Semantic Relations from Descriptive Text
Da Huang

2. Outline Introduction Methodology Evaluation Conclusion
An Intuitive Method
Our Ontology-Based Approach
Evaluation
How to Evaluate
Results
Conclusion

3. Outline Introduction Methodology Evaluation Conclusion
An Intuitive Method
Our Ontology-Based Approach
Evaluation
How to Evaluate
Results
Conclusion

4. Introduction Linked data has great advantage over plain text.
Most information on the web is plain text.
Consider converting plain text to linked data.
As most valuable information are contained in descriptive text (those text which describs an entity), we do our research mainly on this kind of plain text.
简单说明一下什么是“descriptive text”

5. “child”最好改成“hasChild”

6. Outline Introduction Methodology Evaluation Conclusion
An Intuitive Method
Our Ontology-Based Approach
Evaluation
How to Evaluate
Results
Conclusion

7. An Intuitive Method
Is purely NLP, and doesn’t depend on existed ontology.
Suitable for those situations where ontology is poor.
The choice of key words set is critical.

9. 可以考虑把这个图分到两张ppt中，不然图太小了

10. Our Ontology-Based Approach
Depends on ontology.
Divided into two parts:
Extraction: run on parse tree to ease deviation accumulation.
Matching

11. 对于“works at [INFO]”起什么名字？是叫做“matching pattern”还是叫做“relation template” 这个叫“relation template”似乎比较好

13. Outline Introduction Methodology Evaluation Conclusion
An Intuitive Method
Our Ontology-Based Approach
Evaluation
How to Evaluate
Results
Conclusion

14. Evaluation Evaluate with recall and precision.
However is not easy, because we don’t know exactly the text (dbpedia abstract) contains which triples, although we know an entity’s descriptive text and infobox properties.
some relations are in ontology, but not in text.
some relations are in text, but not in ontology.
precision

15. How to Evaluate
Consider the particularity of the situation where property value is Proper Noun.
Those values that both match patterns and are PN, are the true values in high probability.

17. Recall ontology-based: 0.325 intuitive method (synonyms): 0.004
intuitive method (synonyms & all pattern key workds): 0.107

18. Precision ontology-based: 0.629 intuitive method (synonyms): 0.086
intuitive method (synonyms & all pattern key workds): 0.089

19. Outline Introduction Methodology Evaluation Conclusion
An Intuitive Method
Our Ontology-Based Approach
Evaluation
How to Evaluate
Results
Conclusion

20. Conclusion
We come up with an ontology-based approach to extract semantic relations from descriptive text, and it performs better than an intuitive method.
The results may be due to:
intuitive method’s deviation accumulation on dependencies graph.
intuitive method not good at dealing with complex syntactic structure.
However, this approach doesn’t fit when the ontology is poor.

21. Thanks