Generating collaborative systems for digital libraries: A model-driven approach

This is an open access article shared under a Creative Commons Attribution 3.0 Licence (http://creativecommons.org/licenses/by/3.0/). Copyright @ 2010 The Authors.The design and development of a digital library involves different stakeholders, such as: information architects, librarians, and domain experts, who need to agree on a common language to describe, discuss, and negotiate the services the library has to offer. To this end, high-level, language-neutral models have to be devised. Metamodeling techniques favor the definition of domainspecific visual languages through which stakeholders can share their views and directly manipulate representations of the domain entities. This paper describes CRADLE (Cooperative-Relational Approach to Digital Library Environments), a metamodel-based framework and visual language for the definition of notions and services related to the development of digital libraries. A collection of tools allows the automatic generation of several services, defined with the CRADLE visual language, and of the graphical user interfaces providing access to them for the final user. The effectiveness of the approach is illustrated by presenting digital libraries generated with CRADLE, while the CRADLE environment has been evaluated by using the cognitive dimensions framework

Lightweight Federation of Non-Cooperating Digital Libraries

This dissertation studies the challenges and issues faced in federating heterogeneous digital libraries (DLs). The objective of this research is to demonstrate the feasibility of interoperability among non-cooperating DLs by presenting a lightweight, data driven approach, or Data Centered Interoperability (DCI). We build a Lightweight Federated Digital Library (LFDL) system to provide federated search service for existing digital libraries with no prior coordination. We describe the motivation, architecture, design and implementation of the LFDL. We develop, deploy, and evaluate key services of the federation. The major difference to existing DL interoperability approaches is one where we do not insist on cooperation among DLs, that is, they do not have to change anything in their system or processes. The underlying approach is to have a dynamic federation where digital libraries can be added (removed) to the federation in real-time. This is made possible by describing the behavior of participating DLs in an XML-based language that the federation engine understands. The major contributions of this work are: (1) This dissertation addresses the interoperability issues among non-cooperating DLs and presents a practical and efficient approach toward providing federated search service for those DLs. The DL itself remains autonomous and does not need to change its structure, data format, protocol and other internal features when it is added to the federation. (2) The implementation of the LFDL is based on a lightweight, dynamic, data-centered and rule-driven architecture. To add a DL to the federation, all that is needed is observing a DL\u27s interaction with the user and storing the interaction specification in a human-readable and highly maintainable format. The federation engine provides the federated service based on the specification of a DL. A registration service allows dynamic DL registration, removal, or modification. No code needs to be rewritten or recompiled to add or change a DL. These notions are achieved by designing a new specification language in XML format and a powerful processing engine that enforces and implements the rules specified using the language. (3) In this thesis we explore an alternate approach where searches are distributed to participating DLs in real time. We have addressed the performance and reliability problems associated with other distributed search approaches. This is achieved by a locally maintained metadata repository extracted from DLs, as well as an efficient caching system based on the repository

Building Digital Libraries from Simple Building Blocks

Metadata harvesting has been established by the Open Archives Initiative (OAI) as a viable mechanism for connecting a provider of data to a purveyor of services. The Open Digital Library (ODL) model is an emerging framework which attempts to break up the services into appropriate components based also on the basic philosophy of the OAI model. This framework has been applied to various projects and evaluated for its simplicity, extensibility and reusability to support the hypothesis that digital libraries (DLs) should be built from simple Web Service-like components instead of as monolithic software applications

Digital Library Architecture

Digital library is a very complex system. A digital library can have multi-tier architecture. Different digital libraries follow different architectures and models. This paper discusses the basic concepts and principles involved in its design and architecture. It further presents an evaluative account of various digital library architectures

Smart Objects and Open Archives

Within the context of digital libraries (DLs), we are making information objects first-class citizens . We decouple information objects from the systems used for their storage and retrieval, allowing the technology for both DLs and information content to progress independently. We believe dismantling the stovepipe of DL-archive-content is the first step in building richer DL experiences for users and insuring the long-term survivability of digital information. To demonstrate this partitioning between DLs, archives and information content, we introduce buckets : aggregative, intelligent, object-oriented constructs for publishing in digital libraries. Buckets exist within the Smart Object, Dumb Archive (SODA) DL model, which promotes the importance and responsibility of individual information objects and reduces the role of traditional archives and database systems. The goal is to have smart objects be independent of and more resilient to the transient nature of information systems. The SODA model fits well with the emerging Open Archives Initiative (OAI), which promotes DL interoperability through the use of simple archives. This paper examines the motivation for buckets, SODA and the OAI, and initial experiences using them in various DL testbeds

Metadata Architecture for Digital Libraries: Conceptual framework for Indian Digital Libraries

This paper describes approach of development of Metadata solution for digital library architecture for resource description and retrieval. This deals with the concept of Metadata [2], the different Metadata standards (Dublin core in particular [5]), Digital library environment, computer network capabilities etc. This paper also discusses two of the Digital Library architecture protocols, for resource description and retrieval. They are STARTS (Stanford Protocol Proposal for Internet Retrieval and Search) [8] and SODA (Smart Objects and Dump Archives)[13] architecture to arrive at a possible protocol that would help to build Indian Digital Libraries [5]. While proposing the new architecture the existing Indian environment with respect to information sources and user's query of the information sources [5.1], which are feasible for launch of this protocol for information processing and retrieval has been dealt with. This is a pilot study which the author has done while doing his Fulbright fellowship in the College of Library Information Studies, University of Maryland, College Park, MD during 1999-2000

Beyond Harvesting: Digital Library Components as OAI Extensions

Reusability always has been a controversial topic in Digital Library (DL) design. While componentization has gained momentum in software engineering in general, there has not yet been broad DL standardization in component interfaces. Recently, the Open Archives Initiative (OAI) has begun to address this by creating a standard protocol for accessing metadata archives. It is proposed that this protocol be extended to act as the glue that binds together various components of a typical DL. In order to test the feasibility of this approach, a set of protocol extensions was created, implemented, and integrated as components of production and research DLs. The performance of these components was analyzed from the perspective of execution speed, network traffic, and data consistency. On the whole, this work has simultaneously revealed the feasibility of such OAI extensions for component interaction, and has identified aspects of the OAI protocol that constrain such extensions

A component assembly approach to digital library systems

With the advent of the Internet came the promise of global information access. In keeping with this promise, Digital Libraries (DLs) began to emerge across the world as a method of providing structured information to their users. These DLs are often created using proprietary monolithic software that is usually difficult to customise and extend. The Open Digital Library (ODL) project was created to demonstrate that DLs can be built as a network of components instead of as monolithic systems. Although the ODL approach has largely been embraced by the DL community, it is not without a few shortcomings. This paper introduces a graphical user interface and its associated framework for creating DLs from distributed components, consequently addressing a number of the limitations of ODL-like systems, as well as presenting a novel and generic approach for creating component-based systems. This system was subject to a user-based evaluation to confirm its utility and provide insights into possible extensions