Architecting an Extensible Digital Repository Anoop Kumar, Ranjani Saigal,Rob Chavez, Nikolai Schwertner Tufts University, Medford, MA

Overview Background Information on the evolution of TDL Design Requirements TDL Architecture Applications that interface with TDL – Tufts DL search – VUE

History of Digital Collections at Tufts About Tufts – Interdisciplinary – Focus on teaching and learning Digital Collections at Tufts – Perseus (Classics) – Tufts University Science Knowledgebase (TUSK-Medicine) – Artifact (Art History) – Digital Collections and Archives (DCA) Bolles, etc – Other (Crime and Punishment)

ProjectsMaterialsTools Perseus DL50 million words, highly structured TEI encoded XML texts of many types. 50,000 images Perseus document management system and tools DCA13 million words, 35,000 images, geospatial datasets multimedia objects Perseus document management system and tools TUSK15,000 documents Includes full-text syllabi, digital slide images, lecture recordings (audio and video) and text notes and exam questions, evaluation forms, and bibliographies linked to full-text articles. Networked course management system interface Artifact2500 images links to the Art History slide collection database containing 120,000 entries. On-demand viewing and searching with Internet- based adaptations of traditional learning aids, such as flashcards, for review and study

Why TDL? (Tufts Digital Library) The collections were continuously expanding adding content in a variety of formats. The architecture of these libraries was not built to accommodate such expansion. Needed a university wide digital repository that can manage the ever increasing content while continuing to service the discipline specific needs and leveraging existing and new tools and service

Designing TDL Digital Collections and Archives partnered with Academic Technology to create a digital library that can manage the content while supporting teaching and learning. Commitment to comply with standards in the library and the open source community. Ensure Scalability, Flexibility, Reusability, Extensibility and Interoperability

Design Requirements Ingest: – Ability to enforce archival standards Management: – Use of information packages to facilitate storage and dissemination – Ability to incorporate content models Persistence: – Use of persistent identifiers – mapped URNs RequirementsSystem Services Unique and persistent identification of materials Naming Service Use of archival information packages (AIP) Digital Object Provider (DOP) Service -- Fedora Use of submission information Packages (SIP) Drop Box, Ingestion Service Use of Dissemination Information Packages (DIP) DOP Service Authentication and integrity checking DOP Service DisseminationDisseminators, Caching Service, Digital Library Application, Search Service AccessSearch Service and other applications

Tufts DL Architecture Fedora Drop Box Fedora Ingestion Service Application Creation Service Search Indexing Service Naming Service Search Index Search Interface Application Data Application Interface Fedora Client M U U A A U - Users M - Manager A - Administrators

Components of TDL ComponentRole Drop Box and Ingestion Service Validation, Tagging, Preprocessing, Ingestion Naming ServiceUnique persistent identifiers mapped to objects (“tufts:dca:central:MS ”) Fedora RepositoryManagement and access framework for digital objects Search and Indexing Service Provides search mechanism Application Creation Service Provides mechanism for external applications to interface with repository

TDL Architecture Drop Box and Ingestion Service Naming Service Fedora Repository Service at Tufts Indexing Service and Search Engine Application Creation Service

Drop Box and Ingestion Service

TDL Architecture Drop Box and Ingestion Service Naming Service Fedora Repository Service at Tufts Indexing Service and Search Engine Application Creation Service

Naming Service Assigns, reserves and resolves URNs URN Format tufts:school name:owner:[collection:]item name tufts:dca:central:MS URN Properties – Provides unique ID to objects deposited into repository – Service assures resolution to unique resource.

TDL Architecture Drop Box and Ingestion Service Naming Service Fedora Repository Service at Tufts Indexing Service and Search Engine Application Creation Service

Fedora Repository Fedora - Key Features Repository at Tufts Content Models at Tufts – Objects, Behaviors and Disseminator Implementation Challenges

Flexible Extensible Data Object Repository Architecture (Fedora) Support for heterogeneous data types Accommodation of new types as they emerge Aggregation of mixed, possibly distributed, data into complex objects The ability to specify multiple content disseminations of these objects The ability to associate rights management schemes with these disseminations.

Storage Device High Bandwidth (20Mb TIFF) HTTP Request Medium Bandwidth (20Mb TIFF) HTTP (200Kb JPEG) Medium Bandwidth Request Caching Service Fedora Processing Service HTTP Server stores URLs for User Applications (200Kb JPEG) Internet Bandwidth HTTP Request Repository Model

Content Model (CM) Hierarchy Specific Implementations (TEI text, EAD text, Encyclopedia, Directory, TIFF image, etc) Text CM getTOC getChunksList getChunk Etc. Image CM getThumbnail getAccessHigh getImageStats Etc. Binary CM getObject getMIME Etc. Collection CM getObjects getInfo Etc. VUE CM getConceptMap getResource Etc. Indexing Disseminators getIndexTerms getForIndexing Etc. Repository-Level Disseminators getArchivalCopy getPreview getClass Etc.

Implementation Challenges Processing Large XML Documents Transforming Large Images Modeling Collections Advanced Search Customized Search Caching Disseminations

TDL Architecture Drop Box and Ingestion Service Naming Service Fedora Repository Service at Tufts Indexing Service and Search Engine Application Creation Service

Indexing Service and Search Engine Indexing – Specialized Polymorphic Disseminators Implementation – Lucene Supported Types of Search – Basic Keyword – Advanced metadata based Accessing the service – HTTP GET/POST – SOAP

TDL Architecture Drop Box and Ingestion Service Naming Service Fedora Repository Service at Tufts Indexing Service and Search Engine Application Creation Service

An important design requirement for TDL was to allow current digital library applications to easily interface with TDL and provide access to the content in the digital library within their own environments in a seamless fashion. Current applications like Perseus can interface with this service to allow their tools to disseminate the content that resides in TDL The service has been designed not only to support current application but also to accommodate the needs of future yet-to- be-defined applications like course management systems, learning tools, portals etc.

Applications Accessing TDL Content Tufts DL Search Visual Understanding Environment (VUE)

Why TDL? (Tufts Digital Library) The collections are continuously expanding adding content in a variety of formats. The current architecture of these libraries is not built to accommodate such expansion. Need a university wide digital repository that can manage the ever increasing content while continuing to service the discipline specific needs and leveraging existing and new tools and service

Future Direction Authentication and authorization service Customization and enhancement to to address a wide variety of needs. Provide automated browsing service for Repository.