PANIC: an integrated approach to the preservation of composite digital objects using Semantic Web services

To date, long-term preservation approaches have comprised of emulation, migration, normalization, and metadata – or some combination of these. Most existing work has focussed on applying these approaches to digital objects of a singular media type: text, HTML, images, video or audio. In this paper, we consider the preservation of composite, mixed-media digital objects, a rapidly growing class of resources. We describe an integrated, flexible system that we have developed, which leverages existing tools and services and assists organizations to dynamically discover the optimum preservation strategy as it is required. The system captures and periodically compares preservation metadata with software and format registries to determine those objects (or sub-objects) at risk. By making preservation software modules available as Web services and describing them semantically using a machine-processable ontology (OWL-S), the most appropriate preservation service(s) for each object (or sub-object) can then be dynamically discovered, composed and invoked by software agents (with optional human input at critical decision-making steps). The PANIC system successfully illustrates how the growing array of available preservation tools and services can be integrated to provide a sustainable, collaborative solution to the long-term preservation of large-scale collections of complex digital objects.