A Semi-Automated Digital Preservation System based on Semantic Web Services Jane Hunter Sharmin Choudhury DSTC PTY LTD, Brisbane, Australia Slides by Ananta GAMPAA

Topics covered Problems Current Strategies Semantic Web Services Motivation Scenario System Architecture System Implementation Evaluation Conclusions

Introduction Address preservation and long-term access issues Digital Objects require constant and expensive maintenance

Problems Media obsolescence Hardware obsolescence Software obsolescence Authoring software Display/Rendering software Operating System File formats obsolescence

Technical Strategies Migration Conversion of older format document to current It can either corrupt or alter appearance It extends the longevity of resource Emulation Save both the data and program used to create Can be an overkill for data archiving Cost Factor and Technical Difficulties Emulate once, used for large number of DO Original data

Technical Strategies Preservation Metadata facilitates which strategy to use Gathering information that is used in the process of preservation (METS) Supports either Emulation or Migration

Related Work National Digital Information Infrastructure and Preservation Program (NDIIPP) Reference Model for an Open Archive Information System (OAIS) National Library of Australia, PANDORA Networked European Deposits Library (NEDLIB) IBM- Universal Virtual Computer UVC

METS Metadata Encoding and Transmission Standard Developed by the Library of Congress Capture of preservation metadata Extensions developed to support preservation and audiovisual content

Proposal Build an Integrated Preservation Framework which supports: Large, heterogeneous, distributed collections Supports Multiple formats Access to wide range of preservation services Decision support Recommender service Dynamic, Scalable, Extensible Cost-effective and semi-automated

Web Services Modular Applications identified by URI Provide business functionality to other applications via internet Accessible using open protocols and data formats like XML, SOAP, HTTP Standard way of enabling web-based application-to-application interoperability

Standards Data exchanged between applications in XML format

Technologies SOAP (Simple Object Access Protocol) Provides message format for communicating and invoking web services WSDL (Web Services Description Language) Describes how to access and publish web service information

Technologies UDDI (Universal Description, Discovery and Integration) Provides a registry that clients can use to publish and discover information about web services Central registry OWL-S (Ontology Web Language for Services) Describes web services semantically Enables discovery, invocation, composition and monitoring automatically

OWL-S Ontology for Preservation Services

OWL-S Semantic Web Services Service Upper level ontology which provides generic Service class Service Profile Used by a service requester to determine if the service meets its criteria Provides service name,description,contact Provides function description in terms of inputs, outputs and preconditions,effects

OWL-S Semantic Web Services Service Model Describes what happens when the service is operated Service Grounding Specifies how an agent can access a service Provides technical implementation details such as protocol, message formats, addressing

OWL-S Service Profile Extension

Motivation Scenario Nancy Pearl, librarian at the Library of Congress’s American Folklife Center Large collection of valuable digital photographs in TIFF version 5.0 Newer version of Image Viewer no longer supports TIFF5.0 RLG recommends that TIFF be replaced by JPEG 2000 format for archiving

Solution Archival – capture of digital objects and preservation metadata Automatic notification of potential obsolescence New recommendations, format, software versions Service Specification and Request Emulation/ Migration, Inputs/ Outputs, Cost, Speed, Reliability, Lossiness Select, Invoke Preservation Service Log Preservation events

PANIC Architecture

Preservation Metadata Input Tool XML Schema based on extended METS schema Preservation metadata is used by Invocation Component

Invocation Component Obsolescence detector – periodically compares preservation metadata for each object with registries Service discovery – provides user interface so collection manager can specify properties of preservation service they are looking for Service Selection – presents services retrieved by discovery agent

Invocation Component Service Invocation – invokes the selected service and updated the preservation metadata Requester Agent – acts as a mediator between the organization’s collections managers and the preservation services on the web.

Notification Component Provides a search and retrieval interface to Software version, Format version and other registries.

Discovery Component Discovery agent – matches service request against OWL-S descriptions of preservation web services Returns a list of web services that match the request

Provider Component Retrieves and invokes the preservation service automatically or manually by the collections manager Preservation service can be invoked locally or remotely

Example Folklife center runs an implementation of the PANIC system PANIC system monitors the collections periodically through software,format registries Notifies for the need to migrate from TIFF to JPEG2000 Collection manager requests specific service attributes PANIC finds suitable service, service is invoked and metadata is updated

System Implementation

Notification

Service Discovery

Service Selection

System Evaluation Tested on a small collection of different formats Need to implement the system in real library or archive Possibly link with Global Digital Format Registry Need to invoke composite services

Conclusion PANIC offers a viable, cost-effective solution to long term preservation of DO It is dynamic, flexible, semi-automated Makes use of existing technologies Scalable and extensible Optimum combination of automation and interactivity

References All the figures are from the following references per.pdfhttp://metadata.net/panic/Papers/JCDL2004_pa per.pdf