1. A CIDOC CRM – compatible metadata model for digital preservation
Panos Constantopoulos and Vicky Dritsou
Information Systems and Databases Laboratory
Department of Informatics
Athens University of Economics and Business

2. Structure of the presentation
Introduction to Digital Preservation
Metadata
Existing proposals
A conceptual preservation metadata model
Properties of the model
Model concepts
Schema
The complete model
Conclusion
Further research
Our research problem is the issue of supporting the web searching by using ontologies. We first give a few statistics about the use of the web today, while next we specify the problems that the current search engines are facing. We then present web catalogues, as they are already known and used. Following is the definition of ontologies and their categories and we especially give some information about the faceted classification schemes. Two main issues are discussed, ontology learning and ontology mapping, while the latter are further analyzed and classified into logic-based and distance-based mapping. Finally, we provide our research plan.
24 October 2006
CIDOC CRM Workshop

3. Introduction to Digital Preservation (1/2)
Two types of perils for digital content exist
Physical: physical destruction of file systems, corruption of digital media, fire, earthquake
Technological: obsolete systems, non-compatible systems, software and formats
Physical perils are more straightforward to confront
By saving multiple copies of digital content:
On different media
At different geographic locations
Technological hazards require a more complex policy to be applied
By following the appropriate preservation strategy
24 October 2006
CIDOC CRM Workshop

4. Introduction to Digital Preservation (2/2)
Digital preservation strategies for technological hazards
Information migration
Technology emulation
Technology preservation
Backwards compatibility
Reliance on standards
Encapsulation
Transformation to non-digital form
Digital archeology
Most strategies require some information to be collected and stored
This is achieved by using metadata
24 October 2006
CIDOC CRM Workshop

5. Metadata
Defined as “data for data” or otherwise “information about information”
Metadata properties
Not necessarily digital
Not autonomous
Digital information needs to pre-exist
Supplementary
Dynamic character
Metadata types
Descriptive
Structural
Administrative
Preservation metadata
They contain elements from all tree types
But which metadata should we choose?
24 October 2006
CIDOC CRM Workshop

6. Existing proposals Several approaches exist
We have studied five widely known ones:
Dublin Core
Open Archival Information Systems (OAIS)
Curl Exemplars Digital Archives (CEDARS)
Pittsburgh Project
National Library of Australia (NLA)
Discussion
None contains inter-related concepts (element lists)
DC: Access-oriented, inadequate
OAIS, CEDARS: very detailed, difficult to use
PP: detailed, necessary/optional elements, use instructions
NLA: Structured elements, object types
24 October 2006
CIDOC CRM Workshop

7. A conceptual preservation metadata model
A parsimonious metadata set derived from
comparison of the afore-mentioned proposals
CIDOC CRM
Metadata elements
Title - Information Carrier
Identifier - Activity
Subject - Right
Language - Actor
Type - Effect
Format - History
Technical Equipment
Relations
24 October 2006
CIDOC CRM Workshop

8. Properties of the model
Each element forms a concept
Contains relationships among concepts
Results in a conceptual model
Compatible with CIDOC CRM
A small number of new concepts
Can serve as an application ontology
A guide for preservation
Independent from preservation strategy
Elements contain all the information required from each strategy
Further details can be added with the extension of concepts
24 October 2006
CIDOC CRM Workshop

9. Model concepts (1/3) Main concept: Digital Object
Subclass of E73 Information Object
Has attributes: Title, Subject, Type, Size, Identifier, Language, Digital Content
Identifiers may be global or local
Global identifiers must be unique
Digital Content allows separation of content from descriptive/administrative aspects
Stored in an Information Carrier
Digital Objects can consist of other digital objects (Complex Objects)
Type: image, text, sound, multimedia,…
Each object type can be formatted in one of a number of specific formats
24 October 2006
CIDOC CRM Workshop

10. Schema (1/3)
24 October 2006
CIDOC CRM Workshop

11. Model concepts (2/3)
Activities have digital objects as input and output, are carried out by Actors and are subject to Rights
Activity types:
Creation
Deletion
Modification
Alteration
Copy
Read
In all of them, except from Read and Deletion, we assume that the output is a new object
We keep the sequence of performed Activities by assigning the appropriate attribute
Effects can be used as a space-saving device when versions need not be kept
24 October 2006
CIDOC CRM Workshop

12. Schema (2/3)
24 October 2006
CIDOC CRM Workshop

13. Model concepts (3/3)
Activities require the appropriate Technical Equipment to be performed
Software
Hardware
These are all specializations of E71 Man-Made Thing
The software needed depends on the Type and Format of the object
Information carrier also requires Technical Equipment
For reading the object
For writing the object
24 October 2006
CIDOC CRM Workshop

14. Schema (3/3)
24 October 2006
CIDOC CRM Workshop

15. The complete model
24 October 2006
CIDOC CRM Workshop

16. Conclusion Metadata elements drawn from existing metadata sets
Conceptual model for digital preservation
Previous works included only lists of metadata elements
Extensible as needed
Compatible with CIDOC CRM
Digital objects as
digital surrogates of non-digital objects
cultural objects by themselves
24 October 2006
CIDOC CRM Workshop

17. Further research Historical processes: Preservation processes:
interpretation
CIDOC CRM domain of application
Preservation processes:
decision and production processes
Prescription and monitoring
Explore differences in modelling requirements
24 October 2006
CIDOC CRM Workshop

18. Thank you for your attention!
24 October 2006
CIDOC CRM Workshop