ServiceTypeExampleForm
Servicetypename Representation Information service
Description Registry/Repository of Representation Information - contains Representation Information of all kinds, and each piece of RepInfo has its own RepInfo so that a Representation Information Network (RIN) can be encoded. Ideally digital objects provided by archives will have an identifier associated with it; that identifier points to the start point of the RepInfo Network. The registry can also be searched in order to help repository managers create RINs from existing RepInfo.

The information needed to understand and use a digital object is termed, in OAIS, “Representation Information”. This is a catch-all term which includes information about a digital object’s format, semantics, software, algorithms, processes and indeed anything else needed.

Contact David Giaretta, Tessella
Source DCC, CASPAR, Tessella, TNA, UDFR
Keywords Representation Information, registry
Scenario A user needs additional RepInfo in order to understand a piece of digitally encoded information. Alternatively a repository wants to avoid creating RepInfo afresh by using existing RepInfo in order to create an AIP. In both cases the Registry can provide the required RepInfo. Note that the RepInfo must cover Structure, Semantics and any Other types. In addition the RepInfo FOR the RepInfo should also be available.

Fuller version: A dataset created by one researcher may need to be used by a second, either contemporaneously or at some later time. This second researcher may come from a different discipline and use different analysis tools. In order to avoid producing misleading results he/she must be able to understand what the data actually means. For example, given an astronomical image in the current FITS format, with its several variants, the researcher would need to be able to extract the values of the pixels of the image from what may be quite a complex and highly tailored digital object. In order to use an analysis tool one would need to know how to deal with these pixel values, their units, their coordinates on the sky and the way in which the photons have been selected e.g. the bandpass of the filters used. Representation Information is the OAIS term for everything that is needed in order to understand a digital object. A registry would help to ensure that the required Representation Information is available in the future and across disciplines.


Your organisation maintains both document and CAD based digitised data. You are happy to use Representation Information Networks (RIN) from your local National Archive (NA) in relation to applying preservation policies to document file formats, but they do not hold any specific policy information relating to the CAD file formats that you hold. In order to overcome this limitation, your instance of Linked Data Pronom is configured to point to your NA for the document formats, but you have established that a large Aerospace Manufacturer has a better RIN store for the CAD data that you hold, so you configure your system to preference this datasource for the CAD formats, as you 'trust' them to have a more up to date preservation policy for the CAD formats than the local NA.
Implementations
  • CASPAR prototype
  • PRONOM Linked data
  • UDFR
  • SCIDIP-ES sustained service (available from 2014 onwards)

Linked Data Pronom -

The PRONOM registry contains (Representation) information about file formats, compression techniques and encoding types. Linked data is about linking up related data on the web, to help expose, share and connect data, information, and knowledge through using URIs and RDF. (Resource Description Framework, aka Triples) Initially this will concentrate on modelling and publishing file format data already stored in PRONOM, using linked data standards. This is the largest core of data within PRONOM, and its first step to transform the data will be to convert existing data to RDF to describe features of each format. The new version of PRONOM will be extensible, so at a later stage the data model will be enhanced to improve other areas of information in the database. Eventually it is hoped linked data from other external data sources will populate PRONOM, transparently showing where the information came from and in doing so develop a more comprehensive technical registry. It is expected that the new version of PRONOM will be an open source system with a completely open code base.

Prototype has been developed, and is now being extended by Tessella as part of the ENSURE project

Nextsteps Work with SCIDIP-ES:
  • Representation Information Registry holding copies of Representation In-formation of all types which can be shared and enhanced by contributions from many people.
  • Virtualisation techniques to facilitate easier integration into contemporary tools
  • Preservation features should be embedded in the "creation" environment, automating/facilitating the generation of necessary representation information (data, models, assumptions, configurations, ...).
  • Knowledge Gap Manager which provides a semi-automated way of identify-ing where additional Representation Information needs to be created, based on information collected by the Orchestrator/Broker
  • Processing Context which helps to maintain information about the pro-cessing history of a dataset

Extend PRONOM Linked Data: Looking at extending the prototype developed to date so that it can clearly demonstrate the capability of accessing Policy information (RIN) from multiple suppliers in an orchestrated way.

Foster work in UDFR.

Finaldestination World-wide loosely federated Registries

A set of services, supported over the long term, which make it easier to maintain adequate Representation Information, particularly after active work on the dataset has ceased or slowed. Automated capturing of the creation and processing context.

An interconnected list of RDF / Linked Data providers of Representation Information Network data. Allows users to tailor their preservation policies based on their choices of who to Trust, and extend their registries with their own RIN as required.

Relevantprojects CASPAR, SCIDIP-ES, ENSURE, UDFR
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Topic revision: r4 - 2012-10-26 - JeffreyVanDerHoeven
 
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