aDORe: A Modular, Standards-Based Digital Object Repository

Abstract

This paper describes the aDORe repository architecture, designed and implemented for ingesting, storing, and accessing a vast collection of Digital Objects at the Research Library of the Los Alamos National Laboratory. The aDORe architecture is highly modular and standards-based. In the architecture, the MPEG-21 Digital Item Declaration Language is used as the XML-based format to represent Digital Objects that can consist of multiple datastreams as Open Archival Information System Archival Information Packages (OAIS AIPs). Through an ingestion process, these OAIS AIPs are stored in a multitude of autonomous repositories. A Repository Index keeps track of the creation and location of all the autonomous repositories, whereas an Identifier Locator registers in which autonomous repository a given Digital Object or OAIS AIP resides. A front-end to the complete environment -the OAI-PMH Federator -is introduced for requesting OAIS Dissemination Information Packages (OAIS DIPs). These OAIS DIPs can be the stored OAIS AIPs themselves, or transformations thereof. This front-end allows OAI-PMH harvesters to recurrently and selectively collect batches of OAIS DIPs from aDORe, and hence to create multiple, parallel services using the collected objects. Another front-end -the OpenURL Resolver -is introduced for requesting OAIS Result Sets. An OAIS Result Set is a dissemination of an individual Digital Object or of its constituent datastreams. Both front-ends make use of an MPEG-21 Digital Item Processing Engine to apply services to OAIS AIPs, Digital Objects, or constituent datastreams that were specified in a dissemination request.

Large Scale Distributed Knowledge Infrastructures

“…Nevertheless, generally, the component-based design of aDORe makes it possible to migrate between different implementations of the software modules without affecting the overall system's functionality. (Van de Sompel et al, 2005) SeerSuite is a set of tools constituting a framework of an academic digital library built automatically by retrieving scientific contents found on the Web. SeerSuite tools are used by a couple of Internet services, most notably by CiteSeer X , an index of publications in computer and information science and related areas such as mathematics or statistics, comprising over one million objects (Teregowda et al, 2010).…”

Digital Object Prototypes: An Effective Realization of Digital Object Types

“…With DOPs, all objects of the same type behave in the same manner; their respective behaviors are dynamically binded to the instances at runtime, while the behaviors are defined once and in one place, increasing management and maintenance capabilities. aDORe [4] deploys a behavior mechanism that, although it is similar to FEDORA, it attaches behaviors to stored digital objects in a more dynamic fashion, upon dissemination time, using disseminator-related rules stored in a knowledge base. Finally, DOPs behaviors operate on digital objects in a more fine-grained manner, since they can explicitly identify and operate upon the contents of FEDORA datastreams.…”

A Standards-based Solution for the Accurate Transfer of Digital Assets

“…An XMLtape is a general-purpose, file-based mechanism devised to store collections of XML documents of the same class by concatenating those XML documents into a well-formed XML file that validates against the XML Schema at http://purl.lanl.gov/STB-RL/schemas/2005-01/tape.xsd/schemas/2005-01/tape.xsd. XMLtapes are used as a persistent storage mechanism in LANL's aDORe repository [32]. But they are also used as a temporary storage medium for OAI-PMH harvesting processes, and are used as such in the described asset transfer process.…”