DePICT : a conceptual model for digital preservation

• Main Author: Dappert, Angela
• Other Authors: Delve, Janet ; Anderson, Charles
• Published: University of Portsmouth 2013
• Subjects: 025.84; Creative Technologies
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577126

Digital Preservation addresses a significant threat to our cultural and economic foundation: the loss of access to valuable and, sometimes, unique information that is captured in digital form through obsolescence, deterioration or loss of information of how to access the contents. Digital Preservation has been defined as “The series of managed activities necessary to ensure continued access to digital materials for as long as necessary” (Jones, Beagrie, 2001/2008). This thesis develops a conceptual model of the core concepts and constraints that appear in digital preservation - DePICT (Digital PreservatIon ConceptualisaTion). This includes a conceptual model of the digital preservation domain, a top-level vocabulary for the concepts in the model, an in-depth analysis of the role of digital object properties, characteristics, and the constraints that guide digital preservation processes, and of how properties, characteristics and constraints affect the interaction of digital preservation services. In addition, it presents a machine-interpretable XML representation of this conceptual model to support automated digital preservation tools. Previous preservation models have focused on preserving technical properties of digital files. Such an approach limits the choices of preservation actions and does not fully reflect preservation activities in practice. Organisations consider properties that go beyond technical aspects and that encompass a wide range of factors that influence and guide preservation processes, including organisational, legal, and financial ones. Consequently, it is necessary to be able to handle ‘digital’ objects in a very wide sense, including abstract objects, such as intellectual entities and collections, in addition to the files and sets of files that create renditions of logical objects that are normally considered. In addition, we find that not only the digital objects' properties, but also the properties of the environments in which they exist, guide digital preservation processes. Furthermore, organisations use risk-based analysis for their preservation strategies, policies and preservation planning. They combine information about risks with an understanding of actions that are expected to mitigate the risks. Risk and action specifications can be dependent on properties of the actions, as well as on properties of objects or environments which form the input and output of those actions. The model presented here supports this view explicitly. It links risks with the actions that mitigate them and expresses them in stakeholder specific constraints. Risk, actions and constraints are top-level entities in this model. In addition, digital objects and environments are top-level entities on an equal level. Models that do not have this property limit the choice of preservation actions to ones that transform a file in order to mitigate a risk. Establishing environments as top-level entities enables us to treat risks to objects, environments, or a combination of both. The DePICT model is the first conceptual model in the Digital Preservation domain that supports a comprehensive, whole life-cycle approach for dynamic, interacting preservation processes, rather than taking the customary and more limited view that is concerned with the management of digital objects once they are stored in a long-term repository.