Digital Libraries INFO 653 Week 6 Xia Lin College of Information Science and Technology Drexel University

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Digital LibrariesINFO 653Week 6Xia
LinCollege of Information Science and
TechnologyDrexel University
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Content Organization

• From Metadata to subject access
• From thesaurus to KOS (Knowledge Organization
  Systems)
• From Digital collections to Semantic Web

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Collection Building

• Important reading
• Creating a Framework of Guidance for Building
  Good Digital Collections (2002).
• By Timothy W. Cole
• First Monday, 7(5), May, 2002.

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Principles of Good Digital Objects

• A good digital object will be produced in a way
  that ensures it supports collection priorities.
• A good object is persistent.
• A good object is digitized in a format that
  supports intended current and likely future use
  or that support the development of access copies
  that support those uses.
• A good object will be named with a persistent,
  unique identifier that conforms to a
  well-documented scheme.
• A good object should be authenticated.
• A good object should be associated with metadata.
  

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Principles of Good Metadata

• Good metadata should be appropriate to the
  materials in the collection, users of the
  collection, and intended, current and likely use
  of the digital object.
• Good metadata supports interoperability.
• Good metadata uses standard controlled
  vocabularies to reflect the what, where, when and
  who of the content.
• Good metadata includes a clear statement on the
  conditions and terms of use for the digital
  object.
• Good metadata records are objects themselves and
  therefore should have the qualities of good
  objects, including archivability, persistence,
  unique identification, etc. Good metadata should
  be authoritative and verifiable.
• Good metadata supports the long-term management
  of objects in collections.

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Principles of Good Digital Collections

• A good digital collection is created according to
  an explicit collection development policy.
• Collections should be described so that a user
  can discover important characteristics of the
  collection,
• A collection should be sustainable over time.
• A good collection is broadly available and avoids
  unnecessary impediments to use.
• A good collection respects intellectual property
  rights.
• A good collection provides some measurement of
  use.
• A good collection fits into the larger context of
  significant related national and international
  digital library initiatives.

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Important Reading

• Library funcitons, scholarly communication, and
  the foundation of the digital libray Laying
  claim to the control zone.
• By Ross Atkinson
• Library Quarterly, 66(3), 1996.

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Do you agree?

• A library, digital or otherwise, is always a
  highly selective subset of available information
  objects, segregated and favored, to which access
  is enhanced and to which the attention of
  client-users is drawn in opposition to objects
  excluded.

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Control Zone

• The Web is an open zone, and a digital library is
  a control zone.
• By creating a control zone that selects some
  objects and excludes others, information
  professionals are using their expertise to point
  users to documents that hold a particular value.
• add access value to those objects of higher
  content value from the perspective of the
  individual client-user
• Responsibility and focus

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Features of Control Zone

• Core definition
• Particularization (Specialization)
• Maintenance
• Certification
• Standardization

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Controlled Zone

• Must be organized
• Classification
• Thesauri
• Ontologies

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What are disadvantages ofControlled zone?

• Selection might limit the access.
• Selection might be bias.
• Knowledge organization supports pre-existing
  concepts, not for new concepts.
• Not user-oriented individual users needs are
  different.
• Lost the tail?

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From metadata to subject access

• Metadata is only the first step for subject
  access
• provide access entries for searching and
  browsing.
• make implicit knowledge explicit.
• make connections among related digital objects.
• reduce ambiguity.

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Systems of Knowledge Organization for Digital
Libraries

• The term knowledge organization systems (KOS) is
  intended to encompass all types of schemes for
  organizing information and promoting knowledge
  management.
• Includes traditional classification schemes,
  subject headings, thesauri, etc.
• Also include less traditional schemes such as
  semantic networks and ontologies.
• All digital libraries use one or more KOS.

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A Taxonomy of KOS
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Common Characteristics of KOS

• KOS impose a particular view of the world.
• The same entity can be characterized in different
  ways depending on the KOS that is used.
• There must be a sufficient commonality between
  the concept in KOS and the real world objects it
  refers.

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KOS Approaches

• KOS imposes a particular view of the world on a
  collection through
• Providing a controlled list
• Controlling synonyms or equivalents
• Linking DL resources to related resources
• Making semantic relationships explicit

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1. Provide a controlled list

• Examples
• Authority files
• Glossaries
• Dictionaries
• Gazetters
• The controlled lists
• provide a standard vocabulary.
• eliminates ambiguity.

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Example Use of pick lists BestCellars.com
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2. Controlling synonyms or equivalents

• Synonymy two or more terms representing the same
  concept or meaning.
• Synonymy exists when two or more different terms
  represent the same or similar concept.

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Synonym Rings
A synonym ring connects a set of words that are
defined as equivalent for retrieval.
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3. Linking resources

• Use KOS to link digital resources
• Linking sequence numbers to biosequence databanks
• Linking individual industrial codes to the full
  scheme
• Linking organism names taxonomic records
• Linking chemical names to molecular structures
• Linking personal names to biographical
  information

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4. Making semantic relationships explicit

• Use existing thesauri
• Use existing classification shcemes
• Create topic maps or ontologies
• Create semantic web

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Planning and Implementing KOS

• Analyzing user needs
• how a KOS might be used with a particular digital
  library for the intended users
• Locating KOS
• Find if there is a suitable KOS
• Build locally if necessary
• Planning the infrastructure for KOS
• Maintaining KOS
• Presenting KOS to the user
• Acquiring intellectual property of KOS

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Topic Maps

• A key component of Semantic Web
• A new ISO standards
• ISO 13250 Topic Maps
• XML-like syntax
• XML Schema
• XTM XML Topic Maps
• XTM Home

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TAO of Topic Maps

• lttopicmapgt
• TOPIC
• topname
• basename
• dispname
• sortname
• OCCURS
• ASSOC
• assocrl
• facet
• fvalue
• addthms
• lt/topicmapgt

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Topic Maps for Knowledge Representation

• Establishing an associative network between
  resources which represent concepts
• Organizing legacy resources into a new
  information/knowledge space, by relating them to
  topics, and associating those topics, in a
  structured way
• Enabling disparate sets of information resources
  to be used together, by interrelating them using
  a unifying conceptual framework

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Ontology

• An ontology is a specification of a
  conceptualization.
• An ontology is a description (like a formal
  specification of a program) of the concepts and
  relationships that can exist for an agent or a
  community of agents.
• An ontology is a commitment to use the shared
  vocabulary in a coherent and consistent manner.

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Work Force Digital Library Ontology
Cases that worked
Concepts (taxonomy and ontology)
Lessons learned
example-of
example-of
Workforce Programs
describes
represents
Policy and regulation Documents
refers-to
Projects
Info Resources
example-of
sponsors
uses
is-part-of
describes
Government
refers-to
example-of
Document
Guides, Handbooks
initiates
is-related-to
write
Organizations
includes
Describes
People
Presentations
example-of
sponsors
Events (conferences, workshops, ...)
Peter Creticos
sponsors
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Why Develop an Ontology?

• To make domain knowledge explicit
• To share common understanding of information
  structure among people and software agents.
• To enable a machine or multiple machines to use
  and share knowledge in some application.
• To help other people understand some area of
  knowledge.
• To help people reach a consensus in their
  understanding of some area of knowledge.

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Tools to build ontology

• Protégé http//protege.stanford.edu/

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Ontology and thesaurus

• Ontology inherits the ideas, purposes, and
  functions of the thesaurus.
• Ontology extends relationships among concepts
  beyond those in thesaurus (NT, BT, RT, Synonyms).
• Ontology intends to be consumed by both human and
  machine.

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Bridge the Gap
Knowledge
Knowledge-based
Information-based
Technical Architecture
Information Architecture
Collection-based
Interface-based
Documents
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Conclusions

• Collections and content organization is one of
  the major challenges of Digital Libraries.
• There are increasing demand for formalized
  (marked up) knowledge.
• There are increasing tools and specification for
  subject access (or knowledge access) to the Web
  and to Digital libraries.