1 / 31

TDT4215 - Introduction

TDT4215 Web-intelligence Main topics: Information Retrieval Large textual document collections Text mining NLP for document analysis Ontologies for document management Examples from Clinical Decision Support How to extract knowledge from large document collections?.

signa
Télécharger la présentation

TDT4215 - Introduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. TDT4215 Web-intelligence Main topics: • Information Retrieval • Large textual document collections • Text mining • NLP for document analysis • Ontologies for document management • Examples from Clinical Decision Support How to extract knowledge from large document collections? TDT4215 - Introduction

  2. Lectures and Exercises Lectures • Øystein Nytrø • Guests:- Laura Slaughter from Oslo University Hospital- A leading guru on clinical ontologies and decision support (TBA) • Mondays 10.15-13.00 in F3 (that’s right, three hours!) Exercises • PhD student Nafiseh Shabib • Tuesdays 16.15-18.00 in F4 All relevant information will be published at http://www.idi.ntnu.no/emner/tdt4215/

  3. Curriculum Baeza-Yates & Ribeiro-Neto: Modern Information Retrieval.Addison-Wesley, 2011. (selected chapters) Manning, Raghavan and Schütze: Introduction to Information Retrieval.Cambridge University Press, 2008.(selected chapters, available for download) Compendium from IDI(selected book chapters and papers) Details are published at the homepage of the course

  4. Assessment • Group project: 25% of grade • Groups of 3-5 people • Discuss a particular theoretical topic • Develop an information retrieval / text mining application • Evaluate application • To be carried out the first half of the term (25th Feb – 7th Apr) • Nafiseh Shabib is responsible for the group project • Individual written examination: 75% of grade • 4th of June • 4 hours written examination (discussions, calculations, no programming) • Based on everything we will learn in the course

  5. Course Characteristics • Experimental science: • No clear answers or theories • Lots of formulas (that are hard to justify) • Reappearance of logics & reasoning in web context • Relevance: • Concerns real-world problems • A basis for knowledge management applications:Search engines, document management systems, publication systems, digital libraries, enterprise business applications, business/web intelligence systems, semantic interoperation/integration software, etc. • Multi-disciplinary: • Combines techniques from several other sciences:Statistics, linguistics, conceptual modeling, artificial intelligence, knowledge representation, query processing and databases, etc.

  6. Projects and Exercises Important • One mandatory project: • Practice in setting up an application • How to evaluate the quality of IR/TM applications? • How to extract knowledge from specific types of text? Which techniques for which types of text? • Exercises: • Examples from lectures • Understand how formulas are used in practice • Be comfortable with “unproven theories” • Representative for examination questions • Exercises are important!

  7. Lecture Plan (1)

  8. Lecture Plan (2)

  9. Lecture Plan (3)

  10. From Documents to Knowledge 80% of organizational data is textual with no proper structure! Document collections Knowledge and documents Document retrieval Text Mining Ontologies

  11. Information Retrieval Text Mining Text Ontology Overall approach Retrieve document Discover knowledge Knowledge elicitation Morpho-syntax Knowledge representation Semantics Existing New

  12. User Document collection Information system Document Collections Domain-dependent or domain-independent Structured or non-structured text Formatted or non-formatted documents Textual or multimedia documents Monolingual and multilingual document collections Centralized or non-centralized document management Confidential or non-confidential Controlled or free addition of documents Stable or non-stable collections

  13. Case 1: SAP at STATOIL SAP used for major internal business processes Named user accounts: 29,000Concurrent users: 3,200 System complexities:894,000 customers18,000 vendors382,000 materials Work orders created each month: 11,000 Sales orders created each month: 245,000 (11,600 per day) Documents produced each month: 2,25 million Growth of database: 35 GB per month (Aug 2001) Document characteristics: highly structured, textual and tabular, formatted, controlled addition, high growth, non-centralized, possibly multilingual

  14. Case 2: Reengineering project at Hydro Agri Objective: Reengineer organization and implement SAP R3 to support business processes Project duration: July 1995 – March 1999 Costs: USD 126 million Staffing: 500+ (140 external consultants) Document management: Specialized Lotus Notes databases Document production: SHARE Training: 1061 docs 868 MB SHARE Test: 1632 docs 218 MB SHARE Development: 12859 docs 218 MB HAE User document.: 1312 docs 133 MB TOTAL: 16864 docs 1437 MB 359 per month 12 per day

  15. Text is Difficult • Most organizational knowledge encoded in textual documents • Unstructured or semi-structured text difficult to retrieve, interpret or analyze • Particular problems: • Inconsistent documents • Incomplete descriptions • Duplicates • Different terminologies/languages/abbreviations/perspectives

  16. Knowledge and Documents One particular document is neededE.g.: What textbook is used in TDT4215? Several documents provide partial answersE.g.: What is the definition of “text mining”? All documents contribute to answerE.g.: Who writes about Rosenborg? Words versus concepts Manual inspection versus automatic reasoning

  17. Document representations Document representations Document representations Document representations identify relevant information query formulation display documents to user Document Retrieval • Information retrieval = information access • Retrieve documents that satisfy a user’s information need from a document collection • Document indexing • Query interpretation • Ranking of retrieved documents • Linguistics and statistics

  18. Document Retrieval Example AllTheWeb from Fast Search & Transfer (2002) Index: 2,1 GB documents Languages supported: 52 Linguistics used: Lemmatization, language identification, phrasing, anti-phrasing, text categorization, clustering, offensive content reduction, finite-state automata 30 mill. queries a day www.alltheweb.com is today part of Yahoo and uses the Inktomi search engine The old AllTheWeb search engine used Yahoo’s verticals

  19. 66 64 64 62 60 Why is Web Search so Difficult? Ref: http://news.netcraft.com • Volume of data: • Document explosion • Document dynamics • Distributed over many computers and platforms • Google (2008): estimated about 40 billion pages (over 1 trillion unique urls) • Multitude of languages: • Multi-lingual web • 40-50 languages used on the web • Many text encoding standards

  20. Query No. of documents évènements 76,000 événements 420,000 evenements 35,000 evénements 95,000 evènements 22,000 évenements 9,000 Top 10 queries according to Zeitgeist 2010 • chatroulette • ipad • justin bieber • nicki minaj • friv • myxer • katy perry • twitter • gamezer • facebook Why is Web Search so Difficult? • Document Quality: • Misspellings • Spam and offensive content • Little text • All topics • User Behavior: • Misspellings • Query length: avg 2.4 terms • Query session: 8 queries • Half of the documents viewed are among top three documents on result page

  21. Text Mining Part I <html> <body> The professor’s <lem> professor</lem> assistant reads <lem>read</lem> two papers <lem>paper</lem>... </body> </html> <html> <body> The professor’s assistant reads two papers... </body> </html> Index document • Text mining = Linguistic analysis? • Task:Analyze linguistic or statistical content of single documents • Transform document or add information to document • Tagging, lemmatization, NP recognition, etc. • Example: Lemmatization for document retrieval

  22. Text Mining Example 1 David Brown, University for Industry visits the OU John Dominque Wed, 15 Oct 1997 David Brown, the Chairman of the University for Industry Design and Implementation Advisory Group and Chairman of Motorola, visited the OU as part of a fact finding exercise, prior to drafting his initial 100 Days Report to HM Government. David was accompanied by Jeanette Pugh, Josh Hillman and Nick Pearce. SUBJ (1) : DAVID BROWN %COMMA% UNIVERSITY PP (2) : FOR INDUSTRY VB (3) : VISITS OBJ1 (4) : THE OU PUNC(5) : %PERIOD% • Marmot (from UMass) • Sentences are separated and segmented into noun phrases, verb phrases, and prepositional phrases • Recognizes dates and duration phrases • Scopes conjunctions and disjunctions Vargas-Vera et al.: Knowledge Extraction by using an Ontology-based Annotation tool

  23. Knowledge Text Mining Part II • Text mining = knowledge discovery (in text)? • Task:Discover or derive new information from large document collections • find patterns across datasets/documents • separate signal from noise • statistical (and linguistic) approach • Techniques: • Concept extraction • Ontology construction • TOC construction • Clustering • Text categorization • Subtechniques: information extraction, text analysis

  24. Text Mining Example 2 Helsestasjon, helseorganisasjon, journalsystemet, kvalitetsrådgiverprogrammet, miljørettet, Journalopplysninger, sped, helsekortet, skolehelsetenesta, journalforskriften, passord, kravspesifikasjon Datatilsyn, riksarkivar, oppbevaring, pasientjournaler, Retting, journalopplysninger, sletting, Personregisterloven, journal Syndrom, cerebral, alkoholforbruk, mor, hørsel, ben, Misdannelse, leveår, forekomst • Document collection from X • What is the content? • Prominent terms: • Terms used together in text • Journalforskriften: • Mentalretardasjon:

  25. Text Mining Example 3 Helsevesen, hefte, informasjonssikkerhet, Håndbok, standard, pasientjournaler, evt, Minimum, utarbeiding • X = Kompetansesenteret for IT i Helsevesenet (KITH) • Objective: “KITH skal være helsevesenets sentrale rådgiver og kompetanse-organ for bred, samordnet og kostnadseffektiv realisering og anvendelse av informasjons- og kommunikasjonsteknologi." • Terms used together in text • KITH: • What does this say about KITH?

  26. Keyphrase Extraction

  27. Ontologies • Definition of ontology: • Description of entities or concepts and how they are related • Conceptualization of some domain • Purpose: • Semantic description of document collection • Semantic interoperability • Controlled vocabulary for document retrieval • Approaches: • Conceptual modeling • Document analysis and text mining • Standardization work

  28.  Ontology Example 1 Construct ontological model from STATOIL intranet text collection (T. Brasethvik, NTNU)

  29. Ontology Example 2 Current status: • Production plants: 50.000 terms • Geometry and topology: 400 terms • Drilling and logging: 2.700 terms • Production: 2.000 terms • Safety and automation: 150 terms • Subsea equipment: 1.000 terms ISO 15926 Integration of life-cycle data for oil and gas production facilities

  30. Ontology Example 3 Ontology-driven information retrieval

  31. Conclusions • Characteristics of document collections • Technologies for document and knowledge management: • Document retrieval • Text mining • Ontologies • Details of technologies

More Related