Digital libraries: Definition, Evolution, Benefits and Limitations By SURULINATHI M Assistnat Librarian
What are digital libraries? Some definitions: According to Michael Lesk "Digital libraries are organized collections of digital information. They combine the structuring and gathering of information, which libraries and archives have always done, with the digital representation that computers have made possible. "
Definition Cont…. According to William Arms "An informal definition of a digital library is a managed collection of information, with associated services, where the information is stored in digital formats and accessible over a network. A crucial part of this definition is that the information is managed. A stream of data sent to earth from a satellite is not a library. The same data, when organized systematically, becomes a digital library collection. "
Introduction Cont…. According to Ian Witten and David Bainbridge Digital library is "a focused collection of digital objects, inclduing text, video, and audio, along with methods for access and retrieval, and for selection, organization, and maintenance of the collection. "
Digital libraries as "collections" • "A digital library is an organized and focused collection of digital objects, including text, images, video and audio, along with methods for access and retrieval, and for selection, creation, organization, maintenance and sharing of the collection. "
Digital libraries as "institutions" "Digital libraries are organizations that provide the resources, including the specialized staff, to select, structure, offer intellectual access to, interpret, distribute, preserve the integrity of, and ensure the persistence over time of collections of digital works so that they are readily and economically available for use by a defined community or set of communities"
Evolution of digital libraries: DL initiatives: • The growth and the popularity of the Internet and WWW resulted in two major DL initiatives being taken in the mid 1990's in the USA. • First was the joint initiative of the National Science Foundation (NSF), Department of Defence Advanced Research Projects Agency (ARPA), and the National Aeronautics and Space Administration (NASA), in 1994, to fund six digital library development projects for a period of four years, among six academic institutions. The second was the signing of the National Digital Library Federation Agreement in May, 1995, led by the Library of Congress and 14 other research libraries. The purpose was to "bring together - from across the nation and beyond - digitized materials that will be made available to students, scholars and citizens everywhere".
NSF/DARPA/NASA DL initiative targeted three research areas: Capturing, categorizing, organizing information 1. • • Page, speech, video, graphics understanding Indexing, hypermedia linking, knowledge representation Searching, browsing, filtering, summarizing, visualization 2. • • Theories, models, intelligent processing, learning Simulation, navigation, metaphors, optimization Networking protocols and standards, using networked information 3. • Security, compression, modelling, IPR
Technical developments: Several technical developments have contributed to the interest in developing DLs: • Declining cost of digital storage (decreasing by about 30% per year) • In 1987, CD-ROM storage was cheaper than storing books in libraries • Today, storing information on computers is cheaper than storing physical equivalents • PC display screens are more pleasant to use now - and improving further • More and more people are reading directly from computers (e. g. e-books)
Technical developments: • High-speed networks are becoming widespread • Internet and intranets • DSL, DTH, ISDN, etc. • Computers have become portable • Laptops can be connected to the Internet almost from anywhere and DLs can be accessed • Laptops have become more powerful and cheaper • • Sophisticated digitization technologies (capturing devices like scanners, and conversion software) Increasing availability of digital library software (commercial, open source free software)
Benefits of DLs: • DL brings the library to the user • 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 • There is a library wherever there is a PC and a network connection • Improved access - Searching and browsing • Support full text searching - finding information in paper-based material is very difficult • Search systems are improving • Hypertext linking • Information can be shared more easily • Placing digital information on a network makes it available to everybody - mirror sites improve access further - duplication of paper material is very expensive • Easier to keep information current • Information can be updated continuously much more easily
• Information is always available • Not limited by time and geography (3 A's - any time, any where, any format) • Materials are never checked out, mis-shelved, or stolen • New forms of information become possible • Digital representation can support features and manipulations not possible in print form (e. g. chemical structures, mathematical equations, multi-media) • Wider access • A digital library can meet simultaneous access requests for the same electronic document by easily creating multiple instances (or copies) of the requested document. A digital library can thus meet requirements of much larger population of users.
• Allow collaboration and exhange of ideas • Technology of DL is closely related to e-mail and teleconferencing • Potential for convergence • Integration with KM • DLs may save money • Hard data is not yet available • Conventional libraries are expensive - buidling, professional staff, maintenance • Today's DLs are also expensive - but as technology costs decline and improved tools become available, DLs may eventually prove to be less expensive • Improved preservation • It is easier to copy digital information, without errors - no fear of maintaining one physical object permanently. So rare pblications and artifacts may be preserved better by providing access to their digital versions.
Limitations: • Technological obsolescence • Hardware and Sofware • • Cost of content refreshing Rights management • It is very easy to copy, replicate, massage and distribute digital information. Enforcing copyright in digital environment is a major issue. • Inter-operability • Another key issue is that of interworking of different digital libraries. • Network bandwidth