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Open Information Extraction From The Web Rani Qumsiyeh.

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Presentation on theme: "Open Information Extraction From The Web Rani Qumsiyeh."— Presentation transcript:

1 Open Information Extraction From The Web Rani Qumsiyeh

2 What is Information Extraction  This article surveys a range of Information Extraction methods. (Particularly Open)  A venerable technology that maps natural language text into structured relational data.  Open Information Extraction is where the identities of the relations to be extracted are unknown and the billions of documents found on the Web necessitate highly scalable processing.

3 Most common Ways to do IE  Direct knowledge-based encoding. A human enters regular expressions or rules.  Supervised learning. A human provides labeled training examples.  Self-supervised learning. The system automatically finds and labels its own examples.

4 Direct Knowledge  Not efficient, has to be altered for different domains.  Class PhysicalTarget space to the term bank in the terrorism domain.  Class Corporation in the joint-ventures domain

5 Example of Supervised Learning

6 Self Supervised Knowledge  A system that labels its own training examples. (Example: KnowItAll)  For a given relation Use generic pattern  instantiate relation- specific extraction rules  learn domain- specific extraction rules  apply rules to web pages and assign them probabilities.  Example: X is a Y (X is a country). China is a country. Garth Brooks is a country singer

7 Open Information Extraction  The challenge of Web extraction is to be able to do Open Information Extraction. Unbounded number of relations Web corpus contains billions of documents.

8 How open IE systems work  learn a general model of how relations are expressed (in a particular language), based on unlexicalized features such as part-of-speech tags. (Identify a verb)  Learn domain-independent regular expressions. (Punctuations, Commas).

9 Is there a general model of relationships in English

10 TextRunner  Works in two phases. 1. Using a conditional random field, the extractor learns to assign labels to each of the words in a sentence. 2. Extracts one or more textual triples that aim to capture (some of) the relationships in each sentence.

11 Additional Tasks to Accomplish  Opinion mining: in which Open IE can extract opinion information about particular objects (including products, political candidates, and more) that are contained in blog, posts, reviews, and other texts.  Fact checking: in which Open IE can identify assertions that directly or indirectly conflict with the body of knowledge extracted from the Web and various other knowledge bases.


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