Introducing Digital Libraries

Eskinder Asmelash

AKSUM University

2010

The Current Environment

• Web 2.0 / Library 2.0• Blogs / RSS Feeds / Wikis / Podcasts / Webcasts• Open Source Software, Open Standards, Open

URL• User Tagging, Automated Tagging• OA -> OAP + OAA• Open Resource Discovery Tools - Google Scholar• E-Books, E-Journals, E-Resources• Harvesting, Federation, Metasearching• Digital Rights Management

Organizational Transformation in Libraries

• Traditional / Automated» Organization is physical » Shelving of documents - Based on Subject Cln» Key - Index / Catalogues / Cards / Digital Catalgs » Cards - Real/Virtual - Author, Title, Descriptions

• Digital » Organization in terms of digital files /objects» Contains material digitized form» Contains digital material» Architecture » Key - Metadata

Shift in Technologies / Approaches

Traditional Automated Dig. Library

AACR2ISO 2709CCFMARCThesauri

AACR2LCCSDDC / UDCThesauri/LCSH

MetadataDCMI -- W3CEAD, TEI, DTDMETS,MODS, Z39.50MARC21

Limited/ Rigid Efficient/ FlexibleImproved

What is a Digital Library?• A Working definition:

“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, and maintenance of the collection.”

What is a DL?

• Kitchens for knowledge preparation

• WWW ≠ DL!—organization, selectivity

• Nice Web site ≠ DL!—import new documents easily

Collection of digital objects (text, video, audio) alongwith methods for access and retrieval, [user]and for selection, organization, and maintenance [lib]

Workflow in DLs • Selection of source documents

• Content digitization/ acquisition

• Content organization– Metadata preparation, full-text tagging

• Content publishing– Quality control, Content loading

• Content indexing and storage (repository)

• Access and delivery (services)

DL Repository

Functional Components of a Digital Library

Key Components1. Initial conversion of content from

physical to digital form.

2. The extraction or creation of metadata or indexing information describing the content to facilitate searching and discovery, as well as administrative and structural metadata to assist in object viewing, management, and preservation.

Key Components…

3. Storage of digital content and metadata in an appropriate multimedia repository. ◦ The repository will include rights

management capabilities to enforce intellectual property rights, if required. E-commerce functionality may also be present if needed to handle accounting and billing.

Key Components…

4. Client services for the browser, including repository querying and workflow

5. Content delivery via file transfer or streaming media

6. Patron access through a browser or dedicated client

7. A private or public network.

Digital Objects• Technically, a digital library is built up

from simple components, notably digital objects

• A digital object is a way of structuring information in digital form, some of which may be metadata, and includes a unique identifier, called a handle.

Digital Objects …• A single work may have many parts, a

complex internal structure, and one or more arbitrary relationships to other works.

• To represent the complexity of information in the digital library, several digital objects may be grouped together. This is called a set of digital objects.

• All digital objects have the same basic form, but the structure of a set of digital objects depends upon the information it represents.

Digital Objects

What are digital libraries for?• Scholarly communication, education, research

– E-journals, e-books, data sets, e-learning• Access to cultural collections

– Cultural, heritage, historical & special collections, museums, biodiversity

• E-governance– Improved access to government policies,

plans, procedures, rules and regulations • Archiving and preservation• Many more …

DL Software FeaturesDifferent logical document types and

levels◦Book/ chapter, conference/paper, journal/

paper, lecture, project report, photographs, etc

Associate metadata with document types

DL Software Features…

Different document formats◦Word, PDF, HTML, PS, etc.◦Non-Latin scripts

Document acquisition/ publishing◦Online/ offline◦Central/ distributed◦Quality control

DL Software Features…• Indexing and storage

– Automatic metadata extraction

– Structured/full text indexing

– Data compression

• Access and delivery– Structured search, browse, object searching,

hierarchical browsing, fine-grained search

– CD/DVD-ROM distribution

– Personalization, customization

DL Software Features …• Access/ rights management

◦ Who can access? What? How much? Usage restrictions• Usage monitoring and reporting

◦ Who is using? How much? Uptime? Response time? Recall/ Precision? Failures?

• Preservation: Long term access– Link checks, persistent object identification, content

refreshing• Interoperability

– OAI, Z39.50 compliance• Standards compliance

– XML, Dublin Core, Unicode• Scaling up – for large collections