Acceptance of users is amply evident in the exponential growth in the number of electronic publications. Digital libraries are electronic libraries in which a large number of geographically distributed users can access the contents of large and diverse repositories of electronic objects. Electronic objects include networked text, images, maps, sounds, videos, catalogs of merchandise, and scientific, business and government datasets.
The first real-world applications of computers to libraries began in the early 1950s with IBM and punched card applications to library technical services operations and with the development of the MARC (machine-readable cataloging) standard for digitizing and communicating library catalog information. In 1965, J. C. R. Licklider coined the phrase library of the future to refer to his vision of a fully computer-based library and ten years later, F.W. Lancaster wrote of the soon to come paperless library.
About the same time, Ted Nelson invented and named hypertext and hyperspace. Many other terms have been coined to refer to the concept of a digitized library, including the electronic library, virtual library, a library without walls, and others.
The relatively recent use of the term digital library can be traced to the Digital Libraries Initiative funded by the National Science Foundation, the Advanced Research Projects Agency, and the National Aeronautics and Space Administration in the United States. In 1994 these agencies granted 24.4 million dollars to six US. universities for digital library research, impelled by the sudden explosive growth of the Internet and the development of graphical Web browsers.
The term was quickly ad0pted by computer scientists, librarians, and others. Thus, while the term digital library” is relatively new, work in bringing digitized information resources to libraries (or thinking of digitized information resources as libraries) has a history spanning several decades.
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. ( DLF, 1999) Digital Libraries are to collect, store, and organize information in digital forms, and make it available for searching, retrieval, and processing via communication networks all in user-friendly ways.
- Develop improved technology for digitizing analog materials:
- Establish protocols and standards to facilitate the assembly of distributed digital Libraries:
- Address legal concerns associated with access, copying and dissemination of physical and digital materials:
- Integrate access to both digital and physical materials:
- Provide more efficient and more flexible tools for transforming digital content to suit the needs of end-users:
- Develop economic models for. Digital libraries:
Building a digital library is expensive and resource intensive and it is important to know some of the basic principles underlying the design, implementation, and maintenance of any digital library.
Due to the development of information technology the sharing of the information is easy at the global level. The development of Internet together with the web has made the possibility of digital libraries.
Know the content:
The digital libraries need to manage and make decisions about their content, the objects to be included, digitizing items exist only in analog form, possibly marking- up items using standard languages like the Standard Generalized Markup Language ( SGML ), and assigning metadata describing the content and other attributes of each object.
Right people involvement:
Building the better digital library requires a number of fields and professionals. Mainly there are two fields involved in developing the digital libraries are computer personals and Library professionals. Computer personals are designed for the possibilities and limitations of technology and also concerned with the semantic interoperability in the metadata standards in the very large internet information around the globe. Library professionals developing the information retrieval tools, preserving materials for continued access and use and also understanding the information needs of the diverse users.
Design usable system:
Most of the digital libraries are made available through web technology. Website designs account for a number factors including the technical differences among computers and browsers, including speed of access, and users. Accessibility for users with a range of physical disabilities should also be a concern when developing the interface to a digital library. This includes user access to all content; documents that are clear and simple; user control of styles; the availability of context and orientation information; the inclusion of clear navigation mechanisms; and standard markup.
Ensure open access:
Ensuring open access is closely related to usability concerns, including access to the information in the digital library, as well as to the digital library itself and also ensure open access to content is to avoid proprietary hardware and software solutions.
Be(a)ware of data rights:
The digital information may be reproduced, manipulated and accessed by multiple users through networks raises concerns for some publishers wishing to control access to and protect the integrity of their publications. The same technologies that provide vastly enhanced access also raise difficult fundamental issues concerning intellectual property, because the technology that makes access so easy and also greatly aids copying both legal and illegal.
A recent National Research Council report states: The information infrastructure offers both promise and peril; promise in the form of extraordinary ease of access to a vast array of information to be reproduced inappropriately and for information.
Automate wherever possible:
Building a digital library requires significant intellectual effort on the part of the system_s creators, the more automated tools that can be built and used, the better will be the use of precious human resources. These tools need to be easy to use and incorporate real-time aids, including data validation, pull-down lists, report generation, and other time-saving devices.
Content experts use the metadata entry system to add metadata to a master database, entering information only once. The information extracted and combined as needed from the master database to generate HTML pages, search indexes, and reports.
Adopt and adhere to standards:
Design, implementation, and maintenance of digital libraries are more readily scalable, interoperable, and portable. The standards used that are more labor-intensive and important for the aspect of digital libraries. Scanning, metadata entry, and document mark up, all involving the evaluation and handling of individual items in a collection. Delivering the contents of the digital library on the web, using standard, valid, and current HTML, including metadata tags, and other standard web technology increases the chances that other web search engines will be able to find the library. As well as the specific items in it.
Quality metrics can be applied to all the processes and outcomes involved in creating a digital library. They are relevant to selection, metadata entry, image capture, and overall usability of the system.
Develop improved technology for digitizing analog materials:
In order to build a comprehensive resource, historical materials now in analog form (e.g., books, journals, laboratory records, sound recordings, manuscripts, photographs) must be converted. There are few established standards or best practices and a shortage of tools for the objective measurement of reproduction quality. There is a need for more automated support for capturing in explicit data structures the navigational and organizational clues implicit in printed works through page numbers, tables of contents, and indices.
Establish protocols and standards to facilitate the assembly of distributed digital Libraries:
What types of protocols and what degree of standardization on types of digital objects will achieve the balance between feasibility of widespread implementation and coherence of access? Should unified searching use an approach like that found in the 239.50 standards (distributed search) or the approach used by World Wide Web search engines (distributed indexing)? How can distributed digital libraries best safeguard the rights associated with the content (including rights of privacy and conditions imposed by donors as well as copyright) while still providing the broadest possible access?
Address legal concerns associated with access, copying and dissemination of physical and digital materials:
A key element for digital libraries is appropriate recognition and protection of legal rights such as copyright, publicity, privacy, matters of obscenity, defamation intellectual property protection as well as less legalistic but serious concerns associated with the ethics of sharing or providing access to folk or ethnographic materials. The vision for digital libraries includes fluid, easy access to a Wide variety of materials. This is often in conflict with the duties of libraries and archives entrusted with care and management of materials that may be subject to privacy rights or other needs for security.
Integrate access to both digital and physical materials:
A user looking for an item in a library catalog should be able to identify it without regard to whether it is available in its original physical form or as a digital or microfilm reproduction. Even when appropriate catalog records exist, digital content may fail to connect to potential users because individual items in digital collections cannot be retrieved directly or are not identified appropriately support links from traditional catalogs or bibliographic indexes.
Provide more efficient and more flexible tools for transforming digital content to suit the needs of end-users:
The digital libraries are represented in multiple forms or versions. The multiple forms exist to serve varieties of users, function as archival masters, and reduce download time and transmission loads on networks. A content provider may produce large and small versions of images; compressed and uncompressed versions of images, texts, audio, and video; texts formatted for browser software and also formatted for preservation publication; and materials both in proprietary formats and in public or open formats.
This burden of plural, production and maintenance results from the fact that today many digital objects are hard to transform the fly. What technologies can be developed to make digital objects available, migrate-able, and transformable? Similar capabilities are also needed to ensure the preserving of digital content for posterity.
Develop economic models for. Digital libraries:
The creation and maintenance of digital libraries are very expensive. Costs are incurred for production, for the ongoing provision of access, and for the preservation of the digital information. The cost to develop and operate a distributed architecture for long-term archiving, migration, and backup of digital materials will be high. Since the resource is distributed among providers, the net cost tends to be disguised. Libraries would benefit from better estimates of costs and trends in cost for production and maintenance of a corpus of digital information.
The effectiveness of digital information systems is not yet adequate, even though great strides have been made. Existing document search engines exhibit only mediocre precision and recall. Document recognition tools are inaccurate both at the high level of document structure and the low level of character recognition. The Web supports only a fraction of the functionality provided by earlier hypertext systems. Thus, most research has focused on improving accuracy and functionality rather than performance.