Digital libraries: Digital libraries: Definition, Evolution, Definition, Evolution,

Benefits and LimitationsBenefits and Limitations

ByBy

SURULINATHI MSURULINATHI MAssistnat LibrarianAssistnat Librarian

What are digital libraries? What are digital libraries? Some definitions: Some definitions:

According to Michael Lesk According to Michael Lesk

"Digital libraries are organized "Digital libraries are organized collections of digital information. They collections of digital information. They combine the structuring and gathering of combine the structuring and gathering of information, which libraries and archives information, which libraries and archives have always done, with the digital have always done, with the digital representation that computers have made representation that computers have made possible."possible."

Definition Cont….Definition Cont….

According to William ArmsAccording to William Arms"An informal definition of a digital library is a "An informal definition of a digital library is a

managed collection of information, with associated managed collection of information, with associated services, where the information is stored in digital services, where the information is stored in digital formats and accessible over a network. A crucial formats and accessible over a network. A crucial part of this definition is that the information is part of this definition is that the information is managed. A stream of data sent to earth from a managed. A stream of data sent to earth from a satellite is not a library. The same data, when satellite is not a library. The same data, when organized systematically, becomes a digital library organized systematically, becomes a digital library collection." collection."

Introduction Cont….Introduction Cont….

According to Ian Witten and David BainbridgeAccording to Ian Witten and David Bainbridge

Digital library is "a focused collection of Digital library is "a focused collection of digital objects, inclduing text, video, and digital objects, inclduing text, video, and audio, along with methods for access and audio, along with methods for access and retrieval, and for selection, organization, and retrieval, and for selection, organization, and maintenance of the collection."maintenance of the collection."

Digital libraries as "collections"Digital libraries as "collections"

• "A digital library is an organized and "A digital library is an organized and focused collection of digital objects, focused collection of digital objects, including text, images, video and audio, including text, images, video and audio, along with methods for access and along with methods for access and retrieval, and for selection, creation, retrieval, and for selection, creation, organization, maintenance and sharing organization, maintenance and sharing of the collection." of the collection."

Digital libraries as "institutions"Digital libraries as "institutions"

"Digital libraries are organizations that "Digital libraries are organizations that provide the resources, including the provide the resources, including the specialized staff, to select, structure, offer specialized staff, to select, structure, offer intellectual access to, interpret, distribute, intellectual access to, interpret, distribute, preserve the integrity of, and ensure the preserve the integrity of, and ensure the persistence over time of collections of persistence over time of collections of digital works so that they are readily and digital works so that they are readily and economically available for use by a defined economically available for use by a defined community or set of communities"community or set of communities"

Evolution of digital libraries:Evolution of digital libraries:

DL initiatives: DL initiatives: • The growth and the popularity of the Internet and WWW The growth and the popularity of the Internet and WWW

resulted in two major DL initiatives being taken in the mid resulted in two major DL initiatives being taken in the mid 1990's in the USA.1990's in the USA.

• First was the joint initiative of the National Science First was the joint initiative of the National Science Foundation (NSF), Department of Defence Advanced Foundation (NSF), Department of Defence Advanced Research Projects Agency (ARPA), and the National Research Projects Agency (ARPA), and the National Aeronautics and Space Administration (NASA), in 1994, Aeronautics and Space Administration (NASA), in 1994, to fund six digital library development projects for a to fund six digital library development projects for a period of four years, among six academic institutions. period of four years, among six academic institutions. The second was the signing of the The second was the signing of the National Digital Library Federation AgreementNational Digital Library Federation Agreement in May, in May, 1995, led by the Library of Congress and 14 other 1995, led by the Library of Congress and 14 other research libraries. The purpose was to "bring together - research libraries. The purpose was to "bring together - from across the nation and beyond - digitized materials from across the nation and beyond - digitized materials that will be made available to students, scholars and that will be made available to students, scholars and citizens everywhere". citizens everywhere".

NSF/DARPA/NASA DL initiative targeted three NSF/DARPA/NASA DL initiative targeted three research areas:research areas:

1.1. Capturing, categorizing, organizing information Capturing, categorizing, organizing information • Page, speech, video, graphics understanding Page, speech, video, graphics understanding • Indexing, hypermedia linking, knowledge representation Indexing, hypermedia linking, knowledge representation

2.2. Searching, browsing, filtering, summarizing, Searching, browsing, filtering, summarizing, visualization visualization

• Theories, models, intelligent processing, learning Theories, models, intelligent processing, learning • Simulation, navigation, metaphors, optimization Simulation, navigation, metaphors, optimization

3.3. Networking protocols and standards, using Networking protocols and standards, using networked information networked information

• Security, compression, modelling, IPR Security, compression, modelling, IPR

Technical developments:Technical developments:Several technical developments have Several technical developments have

contributed to the interest in developing DLs:contributed to the interest in developing DLs:• Declining cost of digital storage (decreasing by Declining cost of digital storage (decreasing by

about 30% per year) about 30% per year) • In 1987, CD-ROM storage was cheaper than In 1987, CD-ROM storage was cheaper than

storing books in libraries storing books in libraries • Today, storing information on computers is Today, storing information on computers is

cheaper than storing physical equivalents cheaper than storing physical equivalents • PC display screens are more pleasant to use PC display screens are more pleasant to use

now - and improving further now - and improving further • More and more people are reading directly from More and more people are reading directly from

computers (e.g. e-books) computers (e.g. e-books)

Technical developments:Technical developments: • High-speed networks are becoming widespread High-speed networks are becoming widespread

• Internet and intranets Internet and intranets

• DSL, DTH, ISDN, etc. DSL, DTH, ISDN, etc.

• Computers have become portable Computers have become portable • Laptops can be connected to the Internet almost from anywhere Laptops can be connected to the Internet almost from anywhere

and DLs can be accessed and DLs can be accessed

• Laptops have become more powerful and cheaper Laptops have become more powerful and cheaper

• Sophisticated digitization technologies (capturing devices Sophisticated digitization technologies (capturing devices like scanners, and conversion software) like scanners, and conversion software)

• Increasing availability of digital library software Increasing availability of digital library software (commercial, open source free software) (commercial, open source free software)

Benefits of DLs:Benefits of DLs:• DL brings the library to the user DL brings the library to the user

• DL brings information to the user, at work or at home. DL brings information to the user, at work or at home. • With a DL on the desk top, user never need visit a library building With a DL on the desk top, user never need visit a library building • There is a library wherever there is a PC and a network connection There is a library wherever there is a PC and a network connection

• Improved access - Searching and browsing Improved access - Searching and browsing • Support full text searching - finding information in paper-based Support full text searching - finding information in paper-based

material is very difficult material is very difficult • Search systems are improving Search systems are improving • Hypertext linking Hypertext linking

• Information can be shared more easily Information can be shared more easily • Placing digital information on a network makes it available to Placing digital information on a network makes it available to

everybody - mirror sites improve access further - duplication of paper everybody - mirror sites improve access further - duplication of paper material is very expensive material is very expensive

• Easier to keep information current Easier to keep information current • Information can be updated continuously much more easily Information can be updated continuously much more easily

• Information is always available Information is always available • Not limited by time and geography (3 A's - any time, any Not limited by time and geography (3 A's - any time, any

where, any format) where, any format) • Materials are never checked out, mis-shelved, or stolen Materials are never checked out, mis-shelved, or stolen

• New forms of information become possible New forms of information become possible • Digital representation can support features and Digital representation can support features and

manipulations not possible in print form (e.g. chemical manipulations not possible in print form (e.g. chemical structures, mathematical equations, multi-media) structures, mathematical equations, multi-media)

• Wider access Wider access • A digital library can meet simultaneous access requests for A digital library can meet simultaneous access requests for

the same electronic document by easily creating multiple the same electronic document by easily creating multiple instances (or copies) of the requested document. A digital instances (or copies) of the requested document. A digital library can thus meet requirements of much larger library can thus meet requirements of much larger population of users. population of users.

• Allow collaboration and exhange of ideas Allow collaboration and exhange of ideas • Technology of DL is closely related to e-mail and Technology of DL is closely related to e-mail and

teleconferencing teleconferencing • Potential for convergence Potential for convergence • Integration with KM Integration with KM

• DLs may save money DLs may save money • Hard data is not yet available Hard data is not yet available • Conventional libraries are expensive - buidling, professional Conventional libraries are expensive - buidling, professional

staff, maintenance staff, maintenance • Today's DLs are also expensive - but as technology costs Today's DLs are also expensive - but as technology costs

decline and improved tools become available, DLs may decline and improved tools become available, DLs may eventually prove to be less expensive eventually prove to be less expensive

• Improved preservation Improved preservation • It is easier to copy digital information, without errors - no fear It is easier to copy digital information, without errors - no fear

of maintaining one physical object permanently. So rare of maintaining one physical object permanently. So rare pblications and artifacts may be preserved better by providing pblications and artifacts may be preserved better by providing access to their digital versions. access to their digital versions.

Limitations:Limitations: • Technological obsolescence Technological obsolescence

• Hardware and SofwareHardware and Sofware

• Cost of content refreshing Cost of content refreshing • Rights management Rights management

• It is very easy to copy, replicate, massage and It is very easy to copy, replicate, massage and distribute digital information. Enforcing copyright in distribute digital information. Enforcing copyright in digital environment is a major issue. digital environment is a major issue.

• Inter-operability Inter-operability • Another key issue is that of interworking of different Another key issue is that of interworking of different

digital libraries.digital libraries.

• Network bandwidth Network bandwidth