Catálogo de publicaciones - libros

We present a new statistical compression method, which we call Phrase Based Dense Code (PBDC) , aimed at compressing large digital libraries. PBDC compresses the text collection to 30–32% of its original size, permits maintaining the text compressed all the time, and offers efficient on-line information retrieval services. The novelty of PBDC is that it supports continuous growing of the compressed text collection, by automatically adapting the vocabulary both to new words and to changes in the word frequency distribution, without degrading the compression ratio. Text compressed with PBDC can be searched directly without decompression, using fast Boyer-Moore algorithms. It is also possible to decompress arbitrary portions of the collection. Alternative compression methods oriented to information retrieval focus on static collections and thus are less well suited to digital libraries.

eScience has emerged as an important framework for dramatically rethinking the conduct of scientific research using information technology. There is an unparalleled opportunity for the international eScience and digital library communities to create shared infrastructure to support the conduct of science from end-to-end; i.e., from hypothesis generation, to collecting and analyzing scientific data, to the reporting of research outcomes, and the inclusion of scientific data and models in teaching and learning processes. For this vision to be realized, the two communities must establish a shared vision and research agenda encompassing several critical dimensions, including differences in theoretical and methodological approaches, and collaboration goals. Additionally, for the benefits of eScience and digital libraries to be fully realized, it is vital to establish a shared vision of the broader impact of this work for educators, learners, and the general public.

The last decade has seen unprecedented advances in network and distributedsystem technologies, which have opened up the way for the construction of globalscale systems based on completely new conceptions of computation and sharing of resources. The dream of integrating unlimited levels of processing power, unlimited amounts of information, and an unlimited variety of services, and o.ering the entire package in a reliable and seamless fashion to widely distributed users is quickly becoming reality. As Digital Libraries move towards more usercentric, pro-active, collaborative functionality and application diversity, they should be among the first to take advantage of such environments. The long-term vision of the field for creating Dynamic Universal Knowledge Environments calls for intensive computation and processing of very large amounts of information, hence, the needs for the appropriate distributed architecture are pressing.

Managing bibliographic data is a requirement for many researchers. The ShaRef system has been designed to fill the gap between public libraries and personal bibliographies, and provides an open platform for sharing bibliographic data among user groups.

The paper presents the main issues that usually appear in the development of a legislative digital library. The great number of legislative documents which accumulates over the time raises the need for electronic management of this content and the meta-information associated with it. The preparation, the management and the distribution to end users are explained in detail in this paper, offering in the same time an architectural solution for the development of a similar library. A big emphasis was putted on the legislative documents automatic reference linking mechanisms.

Digital Library Management Systems(DLMSs) generally manage collections of multi-media digitalized data and include components that perform the storage, access, retrieval, and analysis of the collections of data. Recently, the new trend of DLMS applications is pushing towards a components/services technology which is becoming more and more standardized [1,2]. The results of this new orientation are ad-hoc solutions for different components and services of DLMS: the data repository, the data manager, the search and retrieval components, etc. We are particularly interested in the evaluation aspects that range from measuring and quantifying the performances of the information access and extraction components of a DLMS to designing and developing an architecture for a system capable of supporting this kind of evaluation in the context of DLMS[3,4].

Emulation is the only strategy to ensure long-term access to digital objects in their original environment. The National Library of the Netherlands (KB) and the Nationaal Archief of the Netherlands believe that emulation-based preservation is worth developing and has to be tested. This short paper proposes a new model for emulation called modular emulation that will allow us to develop a working prototype for the rendering of digital objects in the future.

Research on digital video libraries has been done in extensive and expensive projects (e.g. Open Video Project [1], Físchlár [2], Informedia [3]). Small video collections have small budgets and cannot afford sophisticated techniques to put their material on-line. Though very basic digital video library features can be good enough for enlarging the access to rarely seen material, e.g. folklore films from the 1920’s to the 1990’s owned by the National Centre for English Cultural Tradition (NATCECT). This material is unique but rarely used as the archive opens few hours a week: digital access would make it widely available to scholars, students, and enthusiasts.

Recent advances in digital library technologies are making it possible to build federated discovery services which aggregate metadata from different digital libraries (data providers) and provide a unified search interface to users. In this work we develop a framework that enables data providers to control access to their content in the federation. We have built and tested such a framework based on XACML and Shibboleth.

I present a summary of recent use of the Open Archives Initiative (OAI) registration and validation services for data-providers. The registration service has seen a steady stream of registrations since its launch in 2002, and there are now over 220 registered repositories. I examine the validation logs to produce a breakdown of reasons why repositories fail validation. This breakdown highlights some common problems and will be used to guide work to improve the validation service.