Digital Object Identifier Charles Ellis: Chairman, International DOI Foundation Norman Paskin: Director, International DOI Foundation Steve Stone: Director, Microsoft eBook Product Group Eric Swanson: Chairman, CrossRef doi>

2 Outline Background: why DOI What the DOI system consists of DOI explained: what it does Applications

3 Background: why now? Identifiers enable us to manage content Physical world: ISBN, ISSN, ISMN, SICI, etc good systems for publishers Digital world: ? URL? poor systems for publishers how to use existing identifier systems? Make WWW transactions as invisible as telephone transactions –machine to machine, –not machine to people to machine

4 The intellectual property background Digital world enables both use and misuse Publishers aim is to maximise value of information objects: - reduce copy infringement and - increase accessibility; - we need to identify in order to manage content Mass production  mass customisation - a la carte/ on demand publishing - components must be clearly identifiable - and rights properties of them automated

5 Background: the organisation International DOI Foundation: founded 1998 –following demonstration of prototype in 1997 Not-for-profit; paid membership support –similar principles to World Wide Web Consortium Open to all interested parties Democratic: board elected from members Full time Director 35+ organisations (growing) –Content owners (text publishers, music) –Technology companies –Content intermediaries (etc)

6 DOI: requirements Identification of content –intellectual property in any form Actionable identification –automation; “click to do something” Interoperability –existing identification systems –future developments Open standard –compatible with other standards

7 DOI: the aim Establish a way of identifying content in the digital environment –actionable identifier Which can be the basis of rights management –extensible; can be developed further

8 Components of an identifier A number (or “name”) –assign a number to something –(compare: telephone number)

9 Components of an identifier A number (or “name”) –assign a number to something –(compare: telephone number) A description –say what the number is assigned to –(compare: directory entry)

10 Components of an identifier A number (or “name”) –assign a number to something –(compare: telephone number) A description –say what the number is assigned to –(compare: directory entry) An action –make the number able to do something –(compare: the telephone system)

11 Components of an identifier A number (or “name”) –assign a number to something –(compare: telephone number) A description –say what the number is assigned to –(compare: directory entry) An action –make the number able to do something –(compare: the telephone system) Policies –(compare: social /business structures)

12 POLICIES Syntax /5678 NUMBERING DESCRIPTION Metadata Pieces of data which describe uniquely that which is identified ACTION Resolution System able to link the number to something useful

13 1. Numbering DOI syntax: how the number is made up - NISO standard (Z39.84) / = prefix (e.g. a publisher, a journal, etc) = suffix (combination is unique) An opaque string (“a dumb number”) –once assigned, parts of the number do not have separate meaning Permanent –stays the same even if ownership changes

14 2. Description “What is numbered?” Not as simple as you might think: 1. Not only digital files, but physical things and intangible things! 2. Not only things, but parts of things! Let’s explain these:

15 Manuscript mss #ABC123 paper journal/volume/page Not only digital things...

16 MS Vol/page; ISBN; SICI, etc URL “intangible abstraction” “intangible abstraction”

17 Not only things, but parts of things Components Book –Chapter Section –Figure

18 Not only things, but parts of things Components Book –Chapter Section –Figure “Granularity”

19 Not only things, but parts of things Components Book –Chapter Section –Figure “Granularity” Must be able to identify at whatever level is appropriate : functional granularity

20 Description is by metadata Metadata is: Data Data about other data - Book: ISBN (data) - Price: $12.95 (metadata) - Subject: Buenos Aires (metadata) One man’s metadata is another man’s data:

21 Description is by metadata Data about other data - Subject: Buenos Aires (data) - Book: ISBN (metadata) - Price: $12.95 (metadata) Part of an infinite web : –interconnected –infinite in extent inextricable from “identification ”

22 Description is by metadata Not sufficient to assign an identifier without specifying precisely what the entity is –“ a paper” or “a book” is not precise enough; –must be precise, because: In an automated world, that specification must be by metadata (able to be used by machines) In an interoperable world, that metadata must be –unambiguous (“well-formed”) –follow a data model (able to be used consistently by machines)

23 DOI uses framework Interoperability of data in e-commerce systems Focus is generic intellectual property management Enabling, not replacing, other schemes Broad in scope –description, transaction, rights Based on tested “real world” models, wide support –CIS (music industry); IFLA (library cataloguing) Now in use in real applications –Muze (audiovisuals), EPICS/ONIX (books & serials) Extensible, structured, open standard

24 DOI metadata is very simple A few (7-8) key pieces of data –title, type of content, origin, etc –varies according to what is needed (video, book, etc) about the object –does not include rights metadata but interoperates with rights data –because based on same data model –uses the same terms to mean the same thing analogy: telephone bill = rights information –the telephone number  your bank account

25 Web Browser User etc. Actionable identifier Specified Action doi> / Actions

26 DOI uses Handle System ® Open Standard using internet Distributed, scalable, fast and reliable In use now in several places (e.g. Lib. of Congress) Very simple concept, powerful applications Fits with other standards (URL, URN, etc) Associates a name with “values” (e.g. URL) –input DOI –output URL (or some other defined value)

27 Using Handle, DOIs Resolve to Multiple Data Types DLS loc/repository DOI data / URL Handle (DOI)Data type URL Extensible Data Types XYZ INPUT OUTPUT

28 etc. For convenience we re-draw like this: URL URL2 RAP XYZ doi> /123 INPUTOUTPUT

29 4. Policies DOI free to use –costs paid by assigner DOI applies to any Intellectual Property entity –copyright focus (Berne/WCT etc) Registration agencies to deal with assigning DOIs (and metadata/resolution) for publishers etc Business models determined by agencies Policies for agencies are now evolving

30 POLICIES Allocation of an identifier (DOI) ENUMERATION DESCRIPTION framework allows a DOI to describe any form of intellectual property, at any level of granularity RESOLUTION Handle System allows a DOI to resolve to any piece of current data doi>

31 What is DOI? Digital Object Identifier A unique identifier…. - of a piece of intellectual property - in any form (tangible, intangible) - defined by some key metadata - an opaque string e.g. DOI: /123

32 What is DOI? “resolvable..” - routing, via proven internet technology, “to associated state data”…. - one or more current values of specified types of data (e.g. URL); - these data may be, or link to, services

33 What is DOI? “in an information management substrate…” - once the (meta)data has been obtained, it can interoperate with other data - e.g. about context (subscription etc) - to construct services and transactions - because (meta)data follows a generic interoperable architecture

34 What is DOI? “ A unique resolvable identifier and multiple pieces of associated state data in an information management substrate” achieved by: Technical implementation + policies Two underlying technical tools: 1. intellectual property: framework 2. resolution: Handle System

35 What are the advantages? 1. Identify the item of intellectual property not its location, because: if the location changes the identifier should stay the same (persistence) the same “resource” can be at several locations at the same time (“multiple copies”) DOI does this

36 Web Browser User URL “404 not found” 1. URL is not a persistent identifier - it refers to Location, not content URL ? 2. Same content at two different URLs has two different identifiers - cannot use as common reference “...has moved to…” The problem illustrated on the Web “One in five Web links more than one year old may be out of date” (Alta Vista)

37 Web Browser User URL 1. Don’t change the URL; “persistence is a social, not a technology, problem” Identifiers on the Web  People do change URLs  There are good reasons to change URLs  Does not deal with multiple copies

38 URL Web Browser User URL 2. Assign a Name (= identifier) and redirect for “has moved to..” name Making identifiers persistent  http Bookmarks and caches save the end point, not the name (in current browsers)  still does not deal with multiple copies Identifiers on the Web

39 URL Web Browser User 3. Assign a Name (DOI) and use a better resolver doi>  DOI provides name Identifiers on the Web URL  One point of management  Multiple resolution

40 Web Browser User Resolution 1. DOI is a persistent identifier 2. DOI identifies the content, irrespective of the location doi> /123 This is the DOI: initial implementation URL

41 Web Browser User etc. URL URL2 Data 1 Data 2 Actionable identifier Identifier resolves to any piece of data doi> /123 Full DOI implementation: adding multiple resolution

42 Web Browser User etc. URL2 URL1 URL3 URL4 Multiple resolution for performance: (e.g. D-Lib magazine) Identifier resolves to all URLs; the first to respond is chosen doi> /123

43 Web Browser User etc. URL URL2 Data 1 Data 2 Actionable identifier Specified Action doi> /123 Service /123 Multiple resolution for intelligence: “services”

44 2. Able to deal with relationships: –“this item is a manifestation of that work” –“this item is a part of that item ” DOI does this: DOIs can resolve to other DOIs Metadata can express relationships –“is part of…” etc What are the advantages?

45 URL URL2 Service A Service B doi> URL Service doi> DOI networks can reflect the complex relationships of publishing

46 3. Apply to any intellectual property entity –any format (digital convergence) –any granularity (any part of something) 4. Enable complex actions –can express relationships between entities –interact with data from other sources –enables services (automated, predictable) to be constructed What are the advantages?

47 What are the advantages? 5. Extensible resolution system has capability for trusted transactions metadata framework has capability for full rights management architecture 6. Not limited to current environments not just the Web (other Internet applications) not just digital (intangibles etc)

48 Standards tracking Standards tracking Full implementation Full implementation Initial implementation Initial implementation DOI: development in three tracks Single redirection Metadata W3C, WIPO, NISO, ISO, etc, other initiatives Multiple resolution A continuing development activity

49 Applications Reference linking of articles - CrossRef (full scale DOI implementation, not run by IDF); metadata, single resolution E-books –currently being worked on (with ONIX/EPICS) Images –BioImage; others Books Audiovisuals etc.

50 DOI Deployment DOI Foundation to provide governance –using a federation of registration agencies –agencies follow agreed rules (policies) minimum criteria for registration agencies: –technical; information management; $ does not prescribe details of individual businesses comparable models: –Bar codes (EAN/UPC); Visa; ISBN etc.

51 Summary A general purpose identifier system –number, description, action and policies Any item, at any desired level –using a metadata framework Linking to any service or data –using resolution (multiple resolution) Simple to use –registration agencies Applications and agencies now happening

52 DOI background papers & DOI Annual Review, FAQs, gallery, etc – – Handle system  – Further information doi>