DOI System: overview

Norman PaskinInternational DOI Foundation

Introduction

• Overview: 5 minute animation

then:

• More information on key points

• Q and A

Who?

• DOI = Digital Object Identifier (system) ®• International DOI Foundation (“IDF”)

– Common operations and governing organisation: www.doi.org

• RAs = DOI Registration Agencies – members of IDF offering the DOI system – to customers who wish to assign DOIs– to offer a DOI-based service to users

Status

• Foundation launched to develop system in 1998. • An ISO standard: ISO 26324 • Currently used by c. 11,000 naming authorities

(assigners) • e.g. 3,000 STM publishers, science data sets,

entertainment industry, EU documents, etc.• 87 million DOIs assigned to date • Via 9+ RAs (international)• DOI services provided by RAs: build on DOI system• Initial applications mainly are simple redirection to a

URL. • More sophisticated functionality available e.g. multiple

resolution

Scope

• Digital Identifier of an Object • Object = any entity (thing: physical, digital, or

abstract) • Resources, parties, licences, etc.• Initial focus was documents/media e.g. articles, data

sets.• Now also moving into parties and licences. • Extending to other sectors • Digital Identifier = network actionable identifier (“click

on it and do something”)• Extensible by design: not intended as a publishing-only

solution (digital convergence) • Work with existing tools and data • International: RAs worldwide.

DOIdirectory

URLURL

URL

URL

URL

URL

URL

URL

URL

URL

URL

URL

URL

URL

Content

Content

Managed DOI

DOIdirectory

DOIsystem

DOIDOI

DOI

DOI

DOI

DOI

DOIDOI

DOI

DOI

DOI

DOI

DOI

DOI

What it does

What it does

• provides a resolvable, persistent, interoperable link:

• resolvable – standard identifier syntax + network resolution mechanism (Handle System)

• persistent – through:– technical infrastructure (registry database,

proxy support, etc) – social infrastructure (obligations by

Registration Agencies)• interoperable - through a data model (semantic

interoperability)

• International DOI Foundation • Provides common infrastructure

– Technical: resolution, data model – Social: e.g. obligations for persistence, back-up, in

event of failure, etc.

• Deals with common issues – Standardisation, liaisons, etc.– Outreach to new communities

• “Not for profit” membership federation• Registration Agencies are biggest part of

membership • Elected Board, working groups, meetings• No full time staff (outsourced)

Governance

• RAs are autonomous and independent of each other

• RAs business model with their customers is decided by the RA

• RAs obligation to IDF is a licence/operating agreement

• All RAs share costs of common infrastructure (IDF)• All RAs implement standard DOI system• RAs can add their own services on top • RAs may choose to put DOIs “under the hood” or

make a clear link• Some RAs are commercial; most are themselves

member communities (e.g. CrossRef, EIDR, DataCite)

RAs and the DOI business model

• Handle system: persistent identification in digital networks

• Data model: principles for interoperability of data in e-commerce systems

• Both used elsewhere: aim was to not re-invent the wheel

• Handle: www.handle.net• Data Model: indecs. Linked Content Coalition

Technical infrastructure

URL 2 http://a-books.com/….

XML 3 <some XML>

HS_ADMIN 100 acme.admin/jsmith

XYZ 100111001111012

Data valueDOI

Data type Index

10.123/456 URL 1 http://acme.com/….

Each DOI has one or more Handle values (type:value)

Resolution can return all values, or all values of one type

Schematic of a DOI Handle record

Prefix Suffix

Value(s)

DOI uses Handle to resolve to data

Corporation for National Research Initiatives

Bologna (2)Bologna (2)

Zurich (1)Zurich (1)

Hanover (2)Hanover (2)Denver (1)Denver (1)

Boston (1)Boston (1)Reston (2)Reston (2)

Herndon (15)Herndon (15)

DOI Handle Servers (46 servers in 12 locations)

Singapore – Amazon Cloud (9)Singapore – Amazon Cloud (9)

Beijing (1)Beijing (1)

Tokyo(1)Tokyo(1)

Taipei (1)Taipei (1)

London - Rackspace Cloud (9)London - Rackspace Cloud (9)

DOI Handle technical infrastructure

• High level model (from indecs)

PeoplePeople makemake

Content Content useuse

DealsDeals

aboutaboutdodo

Data model: high level

Agent

PlaceTime

Resource

Context

EntityTypesAn Entity may have typed relationships

with Entities of any kind (including those of its own kind)

EntityTypesAn Entity may have typed relationships

with Entities of any kind (including those of its own kind)

AttributeTypesAn Entity may have Attributes of any kind. (Attributes, which are a type of Resource,

may have their own Attributes).

AttributeTypesAn Entity may have Attributes of any kind. (Attributes, which are a type of Resource,

may have their own Attributes).

Contextual Relationships

RoleRole

RoleRole

RoleRole

RoleRole

RelatorRelator

Descriptor Descriptor

Name Name

Identifier Identifier

Annotation Annotation

Category Category

FlagFlag

QuantityQuantity

Attributes (illustrative: any Entity or Attribute may have Attributes of any type)

Every Relationshiphas a Relator

VerbVerb

Figure 1

COA MetaModel Overview

Non Contextual Relationships (illustrative: any Type of Entity may relate to any other)

Data model: in more detail

• Each DOI has some basic metadata – All DOIs have this “kernel”

• Metadata is held and managed by the RA – Common model for DOI System

• More metadata can be added – Appropriate to an RA or DOI service – Some groups of DOIs will have the same metadata

terms

• Extensible to any level needed • Can use existing metadata and map it to DOI • DOIs with the same service or same metadata

can be grouped and managed as a class

Data Model – end result

• Shared development – e.g. APIs, etc • Shared tools e.g. running mirror servers • Obligations for persistence:

– To customers (within the RA)– In event of failure, etc.(beyond the RA)

• Collaborate • Enable shared DOI services where practical

– A customer could use more than one DOI service

Social infrastructure

• ISO 26324: 2012. • Through TC46/SC9 (“Information and

Documentation”) – same as ISBN etc. • ISO standard contains basic specification • DOI Handbook and procedures has more

detail of implementation

• Other standards:• URI (DOI via http proxy) • URN

Standardisation

• DOI has strong focus on interoperability and on working with existing and new schemes.

• Can take an existing identifier and make it a DOI: – Use the existing identifier in a DOI suffix; or– Define “same as” identifier in the DOI metadata

• Enables re-use of registries, metadata, etc. • Must be certain that the existing ID and the DOI refer

to the same thing (easiest in deal with an existing registry)

• Complicated in digital content:– abstractions (e.g. current version or dated version; abstract

work or specific edition; etc.)– Not always “same as”

• Community and proprietary issues • See “Identifier Interoperability” fact sheet

DOI and other identifier schemes

• Website: www.doi.org

• Quick summary: “Key facts on DOI system” factsheet

• Other Factsheets – more topics in detail:• www.doi.org/factsheets.html

• DOI Handbook

Documentation