Jump to content

Digital library

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by 218.248.80.112 (talk) at 16:47, 5 August 2009 (→Types of digital libraries). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

A digital library is a library in which collections are stored in digital formats (as opposed to print, microform, or other media) and accessible by computers.[1] The digital content may be stored locally, or accessed remotely via computer networks. A digital library is a type of information retrieval system.

The DELOS Digital Library Reference Model[2] defines a digital library as:

An organization, which might be virtual, that comprehensively collects, manages and

preserves for the long term rich digital content, and offers to its user communities specialized

functionality on that content, of measurable quality and according to codified policies.

The first use of the term digital library in print may have been in a 1988 report to the Corporation for National Research Initiatives[3] The term digital libraries was first popularized by the NSF/DARPA/NASA Digital Libraries Initiative in 1994.[4] These draw heavily on As We May Think by Vannevar Bush in 1945, which set out a vision not in terms of technology, but user experience. The term virtual library was initially used interchangeably with digital library, but is now primarily used for libraries that are virtual in other senses (such as libraries which aggregate distributed content).

==

Leaders in the field

Project Gutenberg, Google Book Search, Windows Live Search Books(shutdown), Internet Archive, Cornell University, The Library of Congress World Digital Library, The Digital Library at the University of Michigan, and Carnegie Mellon University's Million Book Project are considered leaders in the field of digital library creation and management.

The future

Large scale digitization projects are underway at Google, the Million Book Project, MSN, and Yahoo!. With continued improvements in book handling and presentation technologies such as optical character recognition and ebooks, and development of alternative depositories and business models, digital libraries are rapidly growing in popularity as demonstrated by Google, Yahoo!, and MSN's efforts. Just as libraries have ventured into audio and video collections, so have digital libraries such as the Internet Archive.

Searching

Most digital libraries provide a search interface which allows resources to be found. These resources are typically deep web (or invisible web) resources since they frequently cannot be located by search engine crawlers. Some digital libraries create special pages or sitemaps to allow search engines to find all their resources. Digital libraries frequently use the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) to expose their metadata to other digital libraries, and search engines like Google Scholar, Yahoo! and Scirus can also use OAI-PMH to find these deep web resources.[5]

There are two general strategies for searching a federation of digital libraries:

  1. distributed searching, and
  2. searching previously harvested metadata.

Distributed searching typically involves a client sending multiple search requests in parallel to a number of servers in the federation. The results are gathered, duplicates are eliminated or clustered, and the remaining items are sorted and presented back to the client. Protocols like Z39.50 are frequently used in distributed searching. A benefit to this approach is that the resource-intensive tasks of indexing and storage are left to the respective servers in the federation. A drawback to this approach is that the search mechanism is limited by the different indexing and ranking capabilities of each database, making it difficult to assemble a combined result consisting of the most relevant found items.

Searching over previously harvested metadata involves searching a locally stored index of information that has previously been collected from the libraries in the federation. When a search is performed, the search mechanism does not need to make connections with the digital libraries it is searching - it already has a local representation of the information. This approach requires the creation of an indexing and harvesting mechanism which operates regularly, connecting to all the digital libraries and querying the whole collection in order to discover new and updated resources. OAI-PMH is frequently used by digital libraries for allowing metadata to be harvested. A benefit to this approach is that the search mechanism has full control over indexing and ranking algorithms, possibly allowing more consistent results. A drawback is that harvesting and indexing systems are more resource-intensive and therefore expensive.

Construction and organization

See also Digital Collections Selection Criteria.

Frameworks

A digital library can be built around specific repository software. The best known examples of this are DSpace, Eprints, Fedora, dLibra(Poland), and Greenstone Digital Library Software. In 2009, Fedora Commons and the DSpace Foundation merged to create a new organization, DuraSpace[6]

The Reference Model for an Open Archival Information System (OAIS) provides a framework to address digital preservation. [7]

Other formal frameworks include the DELOS Reference Model(Agosti, et al., 2006)[8] and the Streams, Structures, Spaces, Scenarios, Societies (5S) formal framework (Gonçalves, Fox, Watson, & Kipp, 2004)[9]

Digitization

In the past few years, procedures for digitizing books at high speed and comparatively low cost have improved considerably with the result that it is now possible to plan the digitization of millions of books per year for creating digital libraries.[10]

See also Digitizing#Collaborative digitization projects.

Advantages

The advantages of digital libraries as a means of easily and rapidly accessing books, archives and images of various types are now widely recognized by commercial interests and public bodies alike.[11]

Traditional libraries are limited by storage space; digital libraries have the potential to store much more information, simply because digital information requires very little physical space to contain it. As such, the cost of maintaining a digital library is much lower than that of a traditional library.

A traditional library must spend large sums of money paying for staff, book maintenance, rent, and additional books. Digital libraries do away with these fees. Both types of library require cataloguing input to allow users to locate and retrieve material. Digital libraries may be more willing to adopt innovations in technology providing users with improvements in electronic and audio book technology as well as presenting new forms of communication such as wikis and blogs; conventional libraries may consider that providing online access to their OPAC catalogue is sufficient. An important advantage to digital conversion is increased accessibility to users. There in also availability to individuals who may not be traditional patrons of a library, due to geographic location or organizational affiliation.

  • No physical boundary. The user of a digital library need not to go to the library physically; people from all over the world can gain access to the same information, as long as an Internet connection is available.
  • Round the clock availability. A major advantage of digital libraries is that people can gain access to the information at any time, night or day.
  • Multiple access. The same resources can be used simultaneously by a number of institutions and patrons. This may not be the case for copyrighted material: a library may have a license for "lending out" only one copy at a time; this is achieved with a system of digital rights management where a resource can become inaccessible after expiration of the lending period or after the lender chooses to make it inaccessible (equivalent to returning the resource).
  • Information retrieval. The user is able to use any search term (word, phrase, title, name, subject) to search the entire collection. Digital libraries can provide very user-friendly interfaces, giving clickable access to its resources.
  • Preservation and conservation. Digitization is not a long-term preservation solution for physical collections, but does succeed in providing access copies for materials that would otherwise fall to degradation from repeated use. Digitized collections and born-digital objects pose many preservation and conservation concerns that analog materials do not. Please see the following "Problems" section of this page for examples.
  • Space. Whereas traditional libraries are limited by storage space, digital libraries have the potential to store much more information, simply because digital information requires very little physical space to contain them and media storage technologies are more affordable than ever before.
  • Added value. Certain characteristics of objects, primarily the quality of images, may be improved. Digitization can enhance legibility and remove visible flaws such as stains and discoloration.[12]

Problems

Digital preservation

Main article: Digital preservation

The work needed to ensure that digital content is maintained and accessible into the future is beginning to be addressed.

Technological standards change over time and forward migration must be a constant consideration of every library. Migration is a means of transferring an unstable digital object to another more stable format, operating system, or programming language.[13] Migration allows the ability to retrieve and display digital objects that are in danger of becoming extinct. This is a rather successful short-term solution for the problem of aging and obsolete digital formats, but with the ever-changing nature of computer technologies, migration becomes this never-ending race to transfer digital objects to new and more stable formats. Migration is also flawed in the sense that when the digital files are being transferred, the new platform may not be able to capture the full integrity of the original object.[14] There are countless artifacts sitting in libraries all over the world that are essentially useless because the technology required to access the source is obsolete. In addition to obsolescence, there are rising costs that result from continually replacing the older technologies. This issue can dominate preservation policy and may put more focus on instant user access in place of physical preservation.[15]

Some people have criticized that digital libraries are hampered by copyright law, because works cannot be shared over different periods of time in the manner of a traditional library. The republication of material on the Web by libraries may require permission from rights holders, and there is a conflict of interest between them and publishers who may wish to create Web versions of their content for commercial purposes.

There is a dilution of responsibility that occurs as a result of the spread-out nature of digital resources. Complex intellectual property matters may become involved since digital material isn't always owned by a library.[16] The content is, in many cases, public domain or self-generated content only. Some digital libraries, such as Project Gutenberg, work to digitize out-of-copyright works and make them freely available to the public. An estimate of the number of distinct books still existent in library catalogues from 2000BC to 1960, has been made.[17][18]

The Fair Use Provisions (17 USC § 107) under copyright law provide specific guidelines under which circumstances libraries are allowed to copy digital resources. Four factors that constitute fair use are purpose of use, nature of the work, market impact, and amount or substantiality used.[19]

Some digital libraries acquire a license to "lend out" its resources. This may involve the restriction of lending out only one copy at a time for each license, and applying a system of digital rights management for this purpose (see also above).

Metadata creation

The ability to find works of interest in large libraries is directly related to how well they are catalogued. While cataloguing electronic works digitised from a libraries' existing holding may be as simple as copying moving a record for the print to the electronic item, with complex and born-digital works require substantially more effort.[20] While full text search can be used for some searches, there are many common catalog searches which can't be performed using full text, including:

References

  1. ^ Greenstein, Daniel I., Thorin, Suzanne Elizabeth. The Digital Library: A Biography. Digital Library Federation (2002) ISBN 1933645180. Accessed June 25, 2007.
  2. ^ L. Candela et al.: The DELOS Digital Library Reference Model - Foundations for Digital Libraries. Version 0.98, February 2008 (PDF)
  3. ^ Kahn, R. E., & Cerf, V. G. (1988). The Digital Library Project Volume I: The World of Knowbots, (DRAFT): An Open Architecture For a Digital Library System and a Plan For Its Development. Reston, VA: Corporation for National Research Initiatives.
  4. ^ Edward A. Fox. The Digital Libraries Initiative - Update and Discussion, Bulletin of the America Society of Information Science, Vol. 26, No 1, October/November 1999.
  5. ^ Koehler, AEC. Some Thoughts on the Meaning of Open Access for University Library Technical Services Serials Review Vol. 32, 1, 2006, p. 17
  6. ^ "Fedora Commons and DSpace Foundation Join Together to Create DuraSpace Organization". Retrieved 2009-06-08.
  7. ^ "The DSpace team recognized the value of the OAIS framework and recast the repository’s architecture to accommodate this archival framework" Baudoin, P. (2004), MIT's DSpace experience: a case study (PDF) {{citation}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  8. ^ Agosti, M., Candela, L., Castelli, D., Ferro, N., Ioannidis, Y., Koutrika, G., Meghini, C., Pagano, P., Ross, S., Schek, H.-J., & Schuldt, H. (2006). A Reference Model for DLMSs Interim Report. In L. Candela, & D. Castelli (Eds.), Deliverable D1.4.2 - Reference Model for Digital Library Management Systems [Draft 1]. DELOS, A Network of Excellence on Digital Libraries -- IST-2002-2.3.1.12, Technology-enhanced Learning and Access to Cultural Heritage. Online at: http://146.48.87.122:8003/OLP/Repository/1.0/Disseminate/delos/2006_WP1_D142/content/pdf?version=1
  9. ^ Gonçalves, M. A., Fox, E. A., Watson, L. T., & Kipp, N. A. (2004). Streams, Structures, Spaces, Scenarios, Societies (5S): A Formal Model for Digital Libraries. ACM Transactions on Information Systems (TOIS),22 (2), 270-312.
  10. ^ Committee on Institutional Cooperation: Partnership announced between CIC and Google, 6 June 2007, Retrieved 7 July 2007.
  11. ^ European Commission steps up efforts to put Europe’s memory on the Web via a “European Digital Library” Europa press release, 2 March 2006
  12. ^ Gertz, Janet. "Selection for Preservation in the Digital Age." Library Resources & Technical Services. 44(2) (2000):97-104.
  13. ^ Cain, Mark. “Managing Technology: Being a Library of Record in a Digital Age”, Journal of Academic Librarianship 29:6 (2003).
  14. ^ Breeding, Marshall. “Preserving Digital Information.”. Information Today 19:5 (2002).
  15. ^ Teper, Thomas H. "Where Next? Long-Term Considerations for Digital Initiatives." Kentucky Libraries 65(2)(2001):12-18.
  16. ^ Pymm, Bob. "Building Collections for All Time: The Issue of Significance." Australian Academic & Research Libraries. 37(1) (2006):61-73.
  17. ^ Antique Books
  18. ^ Kelly, Kevin (2006-05-14). "Scan This Book!". New York Times Magazine. Retrieved 2008-03-07. When Google announced in December 2004 that it would digitally scan the books of five major research libraries to make their contents searchable, the promise of a universal library was resurrected. ... From the days of Sumerian clay tablets till now, humans have "published" at least 32 million books, 750 million articles and essays, 25 million songs, 500 million images, 500,000 movies, 3 million videos, TV shows and short films and 100 billion public Web pages. {{cite news}}: Cite has empty unknown parameter: |coauthors= (help)
  19. ^ Stanford Copyright & Fair Use - Digital Preservation and Copyright by Peter B. Hirtle
  20. ^ http://www.serialssolutions.com/marculator.html

See also

General

Conferences

  • ECDL - European Conference on Digital Libraries
  • ICADL - International Conference on Asian Digital Libraries
  • JCDL - ACM and IEEE Joint Conference on Digital Libraries
  • ICSD - International Conference for Digital Libraries and the Semantic Web
  • EUDL - European Union Digital Library

Tools

Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=Digital_library&oldid=306234880"