Adam Retter

adam@evolvedbinary.com
ย 

The National Archives
2020-05-28


@adamretter

OCDM
(Omega Catalogue
Data Model)

Vocabularies of The OCDM

  • All are recognised and respected standards!

  • Major Use

    • Library of Congress PREMIS3 - Record/Agent Entities

    • DCMI Dublin Core Terms - Record/Agent Description

    • W3C PROV - Provenance (and Versioning)

  • Minor Use

    • W3C ODRL - Closure and Gradated Access

    • RDA - Record/Agent Description

    • Europeana Data Model - Record Sequencing

  • Others

    • FOAF - Agent Description

    • Schema.org - Secondary Identifiers and Dimens.

Provenance and Versioning

  • Knowing how Gov/TNA managed its records has value:

    • For TNA - When/Why/How did we do that?

    • For Readers - How did Gov attitude about a record change?

    • In itself... considered a Public Record???

  • Historically we haven't supported this!

    • PROCat/ILDB - Keeps only the previous change

    • DRI Catalogue - No history. DRI Archive keeps in near-line

    • SAR - History of access constraints

    • Discovery - Does not tell us the custodial history

  • Therefore... Catalogue entries must become Immutable!

  • Breaking down the walls between
    Catalogue and Archive! :-)

  • Public Record

    • As defined by the Public Records Act 1967

    • The physical/digital object itself that is accessioned into the Archive

  • The description of the physical/digital object that goes into the Catalogue

  • Changes to either the physical/digital object or its description

  • Its Identifier?

What constitutes a "Record"?

  • Public Record

    • As defined by the Public Records Act 1967

    • The physical/digital object itself that is accessioned into the Archive

  • The description of the physical/digital object that goes into the Catalogue

  • Changes to either the physical/digital object or its description

  • Its Identifier?

A Record

Changing a Record's Description

  1. Separate the mutable properties from the immutable

Changing a Record's Description

  1. Make a copy of the existing (mutable) description

Changing a Record's Description

  1. Change the copy of the description

Changing a Record's Description

  1. Store additional provenance information

OCDM Record Abstractions

  • Concept of a Record

    • Immutable descriptive properties of a record - Enduring

    • Has "Descriptions" and "Manifestations"

  • Description of a Record

    • Mutable descriptive properties of a record - Transient

    • Represents the description of a record at a point-in-time

  • Manifestation of a Record

    • Technical properties of the physical/digital object

    • One for each physical/digital record (or revision of)

    • Also used for Digitisation & Surrogates!

  • Digital File

Descriptions Through Time

Description with Provenance

  • Every resource in our RDF Graph must have a URI

    • URI has a base followed by a local identifier

  • Base Identifier should use organisation's domain name

    • http://cat.nationalarchives.gov.uk

  • Need Local Identifiers for:

    • Record - Concept, Description, Manifestation, and Digital File

    • Agent - Person, Group, Family, Organisation, Corporate Body, Hardware, and Software

    • Location

Identifiers

  • CCR - Classic Catalogue References (PROCat/ILDB)

    • Convey Knowledge ๐Ÿ‘

      • Ambiguous ๐Ÿคจ

    • Non-Uniform ๐Ÿ˜ž

    • May Change ๐Ÿคซ

    • No facility for Revisions (descriptions) or Manifestations ๐Ÿ˜ข

    • Not Suitable for use in URI ๐Ÿ˜ข

  • GCR - Generated Catalogue References (DRI)

    • Convey less knowledge than CCR ๐Ÿ˜ž

    • Uniform ๐Ÿ‘

    • Never Change ๐Ÿ‘

    • No facility for Revisions (has Manifestations) ๐Ÿคจ

    • Not Suitable (as published) for use in URI ๐Ÿ˜ข

Record Identifiers

IC3240/1916andCE2356/4/1916/Part2
LOC 5/FQQ/Z9
  • Learn from CCR and GCR and improve!

    • Convey Only Immutable Knowledge

      • Never Change ๐Ÿ‘

    • Improved encoding over CCR

      • Shorter Record Numbers ๐Ÿ‘

    • Perfect for use in URI ๐Ÿ‘

  • Different schemes for human vs. machine use

  • Suitable for Linked Data use

  • Can complement existing CCR or GCR

    • or... Should new records only have an OCI???

Omega Catalogue Identifiers

  • Comprised of Four Components

  • Three Immutable Properties for Conveying Knowledge

  • Encodes a Record Number

    • OCI Base25 Alphabet

    • Initialised per Creator Reference and Accession Year pair

  • Has a fixed component separator (full-stop)

  • Syntax

    • Scheme:


    • Examples:

OCI - Concept of a Record

{Creator Reference}.{Accession Year}.{Record Number}.{Accession Format}
MSW.1970.7GH.P
DDPE.2014.L4F.D
  • Comprised of Five Components

    • First four are the same as Concept of a Record

    • Fifth Component is a Description Number

      • Initialised per Concept of a Record

  • Has the same fixed component separator (full-stop)

  • Syntax

    • Scheme:


    • Examples:

OCI - Description of a Record

{Creator Reference}.{Accession Year}.{Record Number}.{Accession Format}.{Description Number}
MSW.1970.7GH.P.1
MSW.1970.7GH.P.2
  • Comprised of Five Components

    • First four are the same as Concept of a Record

    • Fifth Component is a Manifestation Number

      • Initialised per Concept of a Record

  • Has the same fixed component separator (full-stop)

  • Syntax

    • Scheme:


    • Examples:

OCI - Manifestation of a Record

{Creator Reference}.{Accession Year}.{Record Number}.{Accession Format}.M{Description Number}
DDPE.2014.L4F.D.M1
DDPE.2014.L4F.D.M2
  • Concept of a Record

    • Physical


    • Digital


  • Description of a Record




  • Manifestation of a Record

Omega URI Examples

http://cat.nationalarchives.gov.uk/MSW.1970.7GH.P
http://cat.nationalarchives.gov.uk/DDPE.2014.L4F.D
http://cat.nationalarchives.gov.uk/MSW.1970.7GH.P.1
http://cat.nationalarchives.gov.uk/MSW.1970.7GH.P.2
http://cat.nationalarchives.gov.uk/MSW.1970.7GH.P.M1
http://cat.nationalarchives.gov.uk/MSW.1970.7GH.P.M2

Things We haven't talked about

Project Omega, Next Steps...

  • Circulate/Publish Information

    • Omega Catalogue Data Model (PDF)

    • Blogs

      • Archival Catalogue Record Identifiers

      • Archival Identifiers for Digital Files

      • Extreme Identifiers (for use in URI)

  • Export data from ILDB into OCDM RDF

  • Implement (partial) PROCat Replacement

  • Stretch goal: import some DRI Born Digital records

  • Refine OCDM for use by other Archives ???

    • Is it an alternative to RiC-O?

Questions?

Omega Catalogue Data Model

By Adam Retter

Omega Catalogue Data Model

Talk given for Project Omega at The National Archives - 28 May 2020 - remote

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