CS674 Natural Language Processing• Introduction to Information Extraction– Task definition– Evaluation– IE system architectureMonty Python & The Holy GrailInformation needs• What was the name of the enchanter played by John Cleese in the movie “Monty Python and the Holy Grail”?– Ad-hoc IR / Google search– Question answering systems• Describe each character, including the actor who played him or her, in every movie starring John Cleese.Information extraction needmotion-picturetitle:date:plot:characters:…movie-roleactor:character:description:Describe each character, including the actor who played him or her, in every movie starring John Cleese.Information extractionInformation Extraction Systemtext collectionWho: _____What: _____Where:_____When: _____How: _____Who: _____What: _____Where:_____When: _____How: _____Who: _____What: _____Where:_____When: _____How: _____IE system: natural disastersDocument no.: ABC19980530.1830.0342 Date/time: 05/30/1998 18:35:42.49 Disaster Type: earthquake •location: Afghanistan •date: today •magnitude: 6.9 •magnitude-confidence: high •epicenter: a remote part of the country •damage: •human-effect: •victim: Thousands of people •number: Thousands •outcome: dead •confidence: medium •confidence-marker: feared •physical-effect: •object: entire villages •outcome: damaged •confidence: medium •confidence-marker: Details now hard to come by / reports say PAKISTAN MAY BE PREPARING FOR ANOTHER TEST Thousands of people are feared dead following... (voice-over) ...a powerful earthquakethat hit Afghanistantoday. The quakeregistered 6.9 on the Richter scale, centered in a remote part of the country. (on camera) Details now hard to come by, but reports say entire villages were buried by the quake. SAN SALVADOR, 15 JAN 90 (ACAN-EFE) -- [TEXT] ARMANDO CALDERON SOL, PRESIDENT OF THE NATIONALIST REPUBLICAN ALLIANCE (ARENA), THE RULING SALVADORAN PARTY, TODAY CALLED FOR AN INVESTIGATION INTO ANY POSSIBLE CONNECTION BETWEEN THE MILITARY PERSONNEL IMPLICATED IN THE ASSASSINATION OF JESUIT PRIESTS."IT IS SOMETHING SO HORRENDOUS, SO MONSTROUS, THAT WE MUST INVESTIGATE THE POSSIBILITY THAT THE FMLN (FARABUNDO MARTI NATIONAL LIBERATION FRONT) STAGED THIS ASSASSINATION TO DISCREDIT THE GOVERNMENT," CALDERON SOL SAID.SALVADORAN PRESIDENT ALFREDO CRISTIANI IMPLICATED FOUR OFFICERS, INCLUDING ONE COLONEL, AND FIVE MEMBERS OF THE ARMED FORCES IN THE ASSASSINATION OF SIX JESUIT PRIESTS AND TWO WOMEN ON 16 NOVEMBER AT THE CENTRAL AMERICAN UNIVERSITY.IE system: terrorism IE system: output1. DATE - 15 JAN 902. LOCATION EL SALVADOR: CENTRAL AMERICAN UNIVERSITY3. TYPE MURDER4. STAGE OF EXECUTION ACCOMPLISHED5. INCIDENT CATEGORY TERRORIST ACT6. PERP: INDIVIDUAL ID "FOUR OFFICERS""ONE COLONEL""FIVE MEMBERS OF THE ARMED FORCES"7. PERP: ORGANIZATION ID "ARMED FORCES", "FMLN"8. PERP: CONFIDENCE REPORTED AS FACT9. HUM TGT: DESCRIPTION "JESUIT PRIESTS""WOMEN"10. HUM TGT: TYPE CIVILIAN: "JESUIT PRIESTS"CIVILIAN: "WOMEN"11. HUM TGT: NUMBER 6: "JESUIT PRIESTS"2: "WOMEN"12. EFFECT OF INCIDENT DEATH: "JESUIT PRIESTS"DEATH: "WOMEN"IE from semi-structured text• Job postings:– Newsgroups: Rapier from austin.jobs– Web pages: Flipdog• Job resumes: – BurningGlass– Mohomine• Seminar announcements• Company information from the web• Continuing education course info from the web• University information from the web• Apartment rental adsSubject: US-TN-SOFTWARE PROGRAMMERDate: 17 Nov 1996 17:37:29 GMTOrganization: Reference.Com Posting ServiceMessage-ID: <[email protected]>SOFTWARE PROGRAMMERPosition available for Software Programmer experienced in generating software for PC-Based Voice Mail systems. Experienced in C Programming. Must be familiar with communicating with and controlling voice cards; preferable Dialogic, however, experience with others such as Rhetorix and Natural Microsystems is okay. Prefer 5 years or more experience with PC Based Voice Mail, but will consider as little as 2 years. Need to find a Senior level person who can come on board and pick up code with very little training. Present Operating System is DOS. May go to OS-2 or UNIX in future.Please reply to:Kim AndersonAdNET(901) 458-2888 [email protected]: US-TN-SOFTWARE PROGRAMMERDate: 17 Nov 1996 17:37:29 GMTOrganization: Reference.Com Posting ServiceMessage-ID: <[email protected]>SOFTWARE PROGRAMMERPosition available for Software Programmer experienced in generating software for PC-Based Voice Mail systems. Experienced in C Programming. Must be familiar with communicating with and controlling voice cards; preferable Dialogic, however, experience with others such as Rhetorix and Natural Microsystems is okay. Prefer 5 years or more experience with PC Based Voice Mail, but will consider as little as 2 years. Need to find a Senior level person who can come on board and pick up code with very little training. Present Operating System is DOS. May go to OS-2 or UNIX in future.Please reply to:Kim AndersonAdNET(901) 458-2888 [email protected] job postingExtracted job templatecomputer_science_jobid: [email protected]: SOFTWARE PROGRAMMERsalary:company:recruiter:state: TNcity:country: USlanguage: Cplatform: PC \ DOS \ OS-2 \ UNIXapplication:area: Voice Mailreq_years_experience: 2desired_years_experience: 5req_degree:desired_degree:post_date: 17 Nov 1996Web extraction• Many web pages are generated automatically from an underlying database.• Therefore, the HTML structure of pages is fairly specific and regular (semi-structured).• However, output is intended for human consumption, not machine interpretation.• An IE system for such generated pages allows the web site to be viewed as a structured database.• An extractor for a semi-structured web site is sometimes referred to as a wrapper.Flipdog.com Flipdog.comPosting Information extraction (IE)• Identify specific pieces of information (data) in a unstructured or semi-structured textual document.• Transform unstructured information in a corpus of documents or web pages into a structured database.• Applied to different types of text:– Newspaper articles– Web pages– Scientific articles– Newsgroup messages– Classified ads– Medical notesTemplate slot types•