Bilgi Erisim: Temel Kavramlar

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Bilgi Erisim Temel Kavramlar
Yasar Tonta Hacettepe Üniversitesi tonta_at_hacettepe
.edu.tr yunus.hacettepe.edu.tr/tonta/ DOK324/BBY2
20 Bilgi Erisim Ilkeleri
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Plan

• Bilgi tanimi
• Belge tanimi
• Bilgi erisim sistemlerinin mantiksal yapisi
• Temel kavramlar
• Erisim kurallari
• Performans ölçümleri

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Felsefede Bilgi (Knowledge)

• Bilgi
• Bilme etkinligi
• Bu etkinlik sonucu elde edilen çikti
• Bilgi etkinlikleri
• algilama
• anlama
• düsünme
• muhakeme etme
• yorumlama
• açiklama
• dogrulama
• degerlendirme

Kaynak Kuçuradi, 1995, s. 97
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Bilgi Arastirmalarinda Bilgi (Information)

• Süreç olarak bilgi (information-as-process)
• Bilgi olarak bilgi (information-as-knowledge)
• Nesne olarak bilgi (information-as-object)

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Bilgiye Farkli Bakis Açilari
Kaynak Buckland, 1991, s. 6
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Belge

• docere ögretmek, bilgilendirmek
• ment araçlar
• bir fiziksel ya da entellektüel olguyu temsil
  etmek, yeniden yaratmak ya da ispatlamak için
  korunan ya da kaydedilen tüm somut ve sembolik
  dizinsel isaretler (Suzanne Briet)
• Belge örnekleri kil tablet, yontu, papirüs,
  harita, yazma, kitap, dergi, resim, film, kaset,
  CD-ROM, DVD, Web sayfasi, dijital belgeler, vs.

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Farkli Disiplinlerde Belge

• Belge biçim isaret ortam
• Biçim
• Hattatlar, müzik ve sinema yapimcilari, örüntü
  tanima uzmanlari, kütüphaneciler, arsivciler,
  müzeciler
• Isaret
• Dilbilimciler, bilgisayarcilar, yapay zeka
  uzmanlari
• Ortam
• Arsivciler, tarihçiler, hukukçular, diplomatik
  bilimciler, yayincilar, kütüphaneciler, vd.

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Bilgi Yönetimi (Information Management)

• her türlü örgütün etkin olarak isletilmesiyle
  ilgili bilginin saglanmasi, düzenlenmesi,
  denetimi, yayimi ve kullanimina yönetim
  ilkelerinin uygulanmasi
• dogru karar vermek için dogru formda, dogru
  kisiye, dogru maliyetle, dogru zamanda, dogru
  yerde, dogru bilgiyi saglamak

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Bilgi Yönetimi (Knowledge Management)

• bir örgütün misyonunu gerçeklestirmesi için
  örgütün entellektüel sermayesinin kullanimina
  dayanan bir yönetim uygulamasi
• Entellektüel sermaye örgüt çalisanlarinin
  gelistirdigi ya da biriktirdigi deneyim, hizmet
  ve ürünlerden saglanan bilgi (knowledge).
• Bilgi (knowledge)
• Belirtik (nesne olarak bilgi)
• Örtük (bilgi olarak bilgi)

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Bilgi Yöneticisi Neyi Yönetir?

• Insan beyninde sakli örtük bilgileri mi?
• Üzerinde bilgi tasidigi varsayilan nesneleri
  (belgeleri) mi?
• Yoksa her ikisini de mi?
• Kütüphanecilik
• Arsivcilik
• Dokümantasyon - Belge yönetimi Kayit yönetimi -
  Idari dokümantasyon (records management, document
  management)
• Veri yönetimi, Bilgi kaynaklari yönetimi, Bilgi
  teknolojisi yönetimi
• Bilgibilim, bilgi arastirmalari
• Bilgi yönetimi (üzerinde bilgi tasiyan belgelerin
  yönetimi)

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Bilgi Yönetimi (Information Management)

• Belgelerin saglanmasi, düzenlenmesi, yasatilmasi,
  kullanimi, korunmasi, arsivlenmesi
• Kullanicilarin bilgi gereksinimlerinin saptanmasi
  ve karsilanmasi
• Bilgi sistemlerinin tasarlanmasi, kurulmasi ve
  isletilmesi
• Bilgi teknolojisi yönetimi

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Bilgi Erisim

• bilgi toplama, siniflama, kataloglama, depolama,
  büyük miktardaki verilerden arama yapma ve bu
  verilerden istenen bilgiyi üretme (veya gösterme)
  teknigi ve süreci

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Bilgi Erisimin Temel Ikilemi

• Hakkinda bilgi bulmak için bilmedigin bir seyi
  tanimlama geregi (Hjerrpe)

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Bilgi Kesfetme, Tanimlama, Düzenleme ve Erisim
Kesfetme
Kesfetme
Tanimlama
Tanimlama
Düzenleme
Düzenleme
Erisim
Erisim
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Belge Erisim Sisteminin Mantiksal Düzenlemesi
Belgeler
Kullanicilar
Gömü - Sözlük
Sorgu formülasyonu
Dizinleme
Dizin tutanaklari
Formel sorgu cümlesi
Erisim kurali
Kaynak Maron, 1984
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Ideal Bilgi Erisim Sistemi

• Ilgili belgelerin tümüne ve salt ilgili belgelere
  erisim saglamali
• Ilgililik kavrami
• Nesnel ilgililik
• Öznel ilgililik
• Birbirine benzeyen bilgileri bir araya getirmek,
  benzemeyenleri ayirmak

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Background Concepts for IR

• User Information Needs
• Controlled Vocabularies (Pre and
  Post-coordination)
• Indexing Languages
• IR definitions and concepts
• Documents
• Queries
• Collections
• Evaluation
• Relevance

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User Information Need

• Why build IR systems at all?
• People have different and highly varied needs for
  information
• People often do not know what they want, or may
  not be able to express it in a usable form
• Bouldings Image
• How to satisfy these user needs for information?

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Controlled Vocabularies

• Vocabulary control is the attempt to provide a
  standardized and consistent set of terms (such as
  subject headings, names, classifications, etc.)
  with the intent of aiding the searcher in finding
  information.
• Controlled vocabularies are a kind of metadata
• Data about data
• Information about information

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Pre- and Postcoordination

• Precoordination relies on the indexer (librarian,
  etc.) to construct some adequate representation
  of the meaning of a document.
• Postcoordination relies on the user or searcher
  to combine more atomic concepts in the attempt to
  describe the documents that would be considered
  relevant.

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Structure of an IR System
Search Line
Adapted from Soergel, p. 19
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Uses of Controlled Vocabularies

• Library Subject Headings, Classification and
  Authority Files.
• Commercial Journal Indexing Services and
  databases
• Yahoo, and other Web classification schemes
• Online and Manual Systems within organizations
• SunSolve
• MacArthur

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Types of Indexing Languages

• Uncontrolled Keyword Indexing
• Indexing Languages
• Controlled, but not structured
• Thesauri
• Controlled and Structured
• Classification Systems
• Controlled, Structured, and Coded
• Faceted Classification Systems

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Thesauri

• A Thesaurus is a collection of selected
  vocabulary (preferred terms or descriptors) with
  links among Synonymous, Equivalent, Broader,
  Narrower and other Related Terms

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Thesauri (cont.)

• National and International Standards for Thesauri
• ANSI/NISO z39.19--1994 -- American National
  Standard Guidelines for the Construction, Format
  and Management of Monolingual Thesauri
• ANSI/NISO Draft Standard Z39.4-199x -- American
  National Standard Guidelines for Indexes in
  Information Retrieval
• ISO 2788 -- Documentation -- Guidelines for the
  establishment and development of monolingual
  thesauri
• ISO 5964-- Documentation -- Guidelines for the
  establishment and development of multilingual
  thesauri

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Development of a Thesaurus

• Term Selection.
• Merging and Development of Concept Classes.
• Definition of Broad Subject Fields and Subfields.
• Development of Classificatory structure
• Review, Testing, Application, Revision.

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Categorization Summary

• Processes of categorization underlie many of the
  issues having to do with information organization
• Categorization is messier than our computer
  systems would like
• Human categories have graded membership,
  consisting of family resemblances.
• Family resemblance is expressed in part by which
  subset of features are shared
• It is also determined by underlying
  understandings of the world that do not get
  represented in most systems

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Classification Systems

• A classification system is an indexing language
  often based on a broad ordering of topical areas.
  Thesauri and classification systems both use this
  broad ordering and maintain a structure of
  broader, narrower, and related topics.
  Classification schemes commonly use a coded
  notation for representing a topic and its place
  in relation to other terms.

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Classification Systems (cont.)

• Examples
• The Library of Congress Classification System
• The Dewey Decimal Classification System
• The ACM Computing Reviews Categories
• The American Mathematical Society Classification
  System

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Central Concepts in IR

• Documents
• Queries
• Collections
• Evaluation
• Relevance

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Documents

• What do we mean by a document?
• Full document?
• Document surrogates?
• Pages?
• Buckland What is a Document, What is a
  Digital Document
• Are IR systems better called Document Retrieval
  systems?
• A document is a representation of some
  aggregation of information, treated as a unit.

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Collection

• A collection is some physical or logical
  aggregation of documents
• A database
• A Library
• An index?
• Others?

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Queries

• A query is some expression of a users
  information needs
• Can take many forms
• Natural language description of need
• Formal query in a query language
• Queries may not be accurate expressions of the
  information need
• Differences between conversation with a person
  and formal query expression

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Evaluation

• Why Evaluate?
• What to Evaluate?
• How to Evaluate?

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Why Evaluate?

• Determine if the system is desirable
• Make comparative assessments
• Others?

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What to Evaluate?

• How much of the information need is satisfied.
• How much was learned about a topic.
• Incidental learning
• How much was learned about the collection.
• How much was learned about other topics.
• How inviting the system is.

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What to Evaluate?

• What can be measured that reflects users
  ability to use system? (Cleverdon 66)
• Coverage of Information
• Form of Presentation
• Effort required/Ease of Use
• Time and Space Efficiency
• Recall
• proportion of relevant material actually
  retrieved
• Precision
• proportion of retrieved material actually relevant

effectiveness
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Relevance

• In what ways can a document be relevant to a
  query?
• Answer precise question precisely.
• Partially answer question.
• Suggest a source for more information.
• Give background information.
• Remind the user of other knowledge.
• Others ...

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Relevance

• Intuitively, we understand quite well what
  relevance means. It is a primitive y know
  concept, as is information for which we hardly
  need a definition. if and when any productive
  contact in communication is desired,
  consciously or not, we involve and use this
  intuitive notion or relevance.
• Saracevic, 1975 p. 324

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Relevance

• How relevant is the document
• for this user, for this information need.
• Subjective, but
• Measurable to some extent
• How often do people agree a document is relevant
  to a query?
• How well does it answer the question?
• Complete answer? Partial?
• Background Information?
• Hints for further exploration?

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Relevance Research and Thought

• Review to 1975 by Saracevic
• Reconsideration of user-centered relevance by
  Schamber, Eisenberg and Nilan, 1990
• Special Issue of JASIS on relevance (April 1994,
  45(3))

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Saracevic

• Relevance is considered as a measure of
  effectiveness of the contact between a source and
  a destination in a communications process
• Systems view
• Destinations view
• Subject Literature view
• Subject Knowledge view
• Pertinence
• Pragmatic view

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Define your own relevance

• Relevance is the (A) gage of relevance of an (B)
  aspect of relevance existing between an (C)
  object judged and a (D) frame of reference as
  judged by an (E) assessor
• Where

From Saracevic, 1975 and Schamber 1990
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A. Gages

• Measure
• Degree
• Extent
• Judgement
• Estimate
• Appraisal
• Relation

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B. Aspect

• Utility
• Matching
• Informativeness
• Satisfaction
• Appropriateness
• Usefulness
• Correspondence

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C. Object judged

• Document
• Document representation
• Reference
• Textual form
• Information provided
• Fact
• Article

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D. Frame of reference

• Question
• Question representation
• Research stage
• Information need
• Information used
• Point of view
• request

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E. Assessor

• Requester
• Intermediary
• Expert
• User
• Person
• Judge
• Information specialist

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Schamber, Eisenberg and Nilan

• Relevance is the measure of retrieval
  performance in all information systems, including
  full-text, multimedia, question-answering,
  database management and knowledge-based systems.
• Systems-oriented relevance Topicality
• User-Oriented relevance
• Relevance as a multi-dimensional concept

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Schamber, et al. Conclusions

• Relevance is a multidimensional concept whose
  meaning is largely dependent on users
  perceptions of information and their own
  information need situations
• Relevance is a dynamic concept that depends on
  users judgements of the quality of the
  relationship between information and information
  need at a certain point in time.
• Relevance is a complex but systematic and
  measureable concept if approached conceptually
  and operationally from the users perspective.

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Froehlich

• Centrality and inadequacy of Topicality as the
  basis for relevance
• Suggestions for a synthesis of views

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Janes View of Relevance