Digital Libraries have evolved from a digital counterpart of traditional libraries to highly dynamic environments conceived to provide a community with the data and services needed to accomplish its tasks. This trend is particularly frequent in the context of scientific research communities, whose members are scattered among multiple organizations across the world, with requirements that are very large, multi-disciplinary, and evolving with innovation. The realization of such Research Digital Libraries calls for innovative approaches, capable of handling the inherent complexity of such systems while keeping their realization and maintenance costs under sustainable thresholds. Digital Library Infrastructures have been recently proposed as suitable candidates for the realization of Research Digital Libraries. They build on service-oriented infrastructure technologies to offer an environment where organizations can share and exchange their data and service resources to grow in synergy, exploiting an economy of scale approach. This chapter describes the peculiar challenges that designers, developers, and administrators have to face when realizing Research Digital Libraries, and presents the concepts and technologies of Digital Library Infrastructure as possible solutions to these issues.
The Digital Library (DL) concept can be traced back to the famous papers of visionary scientists like Vannevar Bush (1945) and J. C. R. Licklider (1965) identifying and pursuing the goal of innovative technologies and approaches toward knowledge sharing as fundamental instruments for progress. However, research and development activity on digital libraries actually started in the early 1990s; with the Internet proliferation since such technology created unprecedented possibilities to discover and deliver human knowledge.
During these years, a variety of different types of information systems—called “digital libraries”—have been developed in diverse contexts. These systems are very heterogeneous in scope and functionality and their evolution does not follow a single path. In fact, when DL evolve changes happened this has not only meant that a better quality system was been conceived by superseding the “preceding” ones but also meant that a new conception of digital libraries was born corresponding to new raised needs (Candela, Castelli, & Pagano, 2011).
In the last decade, Digital Libraries have achieved a fundamental role in our knowledge-based society, especially in the context of “scientific research.” In this context, the novel multidisciplinary forms of research and the need for immediate and contemporary access to heterogeneous and independently grown content, brought up new and challenging requirements for DLs. DLs evolved from stand-alone systems supporting data storage and provision for the users of one organization, to possibly very-large, cross-domain, cross-organization DL systems tailored to serve continuously evolving needs. In general terms, these new generation of Research DLs (RDLs) are requested to provide user communities with (a) a wealth of content aggregated from existing knowledge providers such as libraries, museum, data archives, and any knowledge repository; and (b) the dynamically evolving applications they need to accomplish their tasks (study, work, leisure) by processing, exploring, accessing and interacting with such content.
Traditional DL development approaches based on from-scratch realization of the entire system proved to be unsuitable. In such scenarios, the costs of design, development, administration and maintenance (e.g., refinement, adaptation to evolution) tend to be not sustainable for organizations responsible of the resulting RDLs (Manghi, Mikulicic, Candela, Castelli, & Pagano, Realizing and Maintaining Aggregative Digital Library Systems: D-NET Software Toolkit and OAIster System, 2010), which are often faced with the trade-off between user satisfaction and lack of funding required to satisfy them.