The Case for Public Resource Identifiers
A Call for Action
Steve Pepper, Ontopia
Identity, Reference, and the Web Workshop, Edinburgh, May 2006
About this presentation
• Just a subset of my paper* for this workshop
– 1. Introduction (on the need for identifiers)
– 2. Requirements on a Global Identifier Mechanism
– 3. Published Subjects
– 4. Alternative Proposals
– 5. Call to Action
• Focus here is on the Call for Action
– Expands on the ideas presented to the W3C AC
• http://www.w3.org/2006/05/pepper
* The Case for Published Subjects,
http://www.ontopia.net/topicmaps/materials/The_Case_for_Published_Subjects.pdf
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
URIs and the Towers of Babel *
• URIs constitute a universal way of naming things
• This has tremendous potential
– Globally unique, language-independent identifiers
for any conceivable subject under the sun
• We could finally stop building Towers of Babel
– (Or at least make a real impression on info glut)
* Whenever I say “URI”, please hear “IRI”
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
The Semantic Superhighway
• At the very least, URIs give us the chance to
create a “semantic superhighway”
– A foundation for solving the problem of infoglut
– A level of the Semantic Web below RDF
• But it’s not happening
– In fact, we are witnessing the creation of new
Towers of Babel
– New, redundant vocabularies appear daily
• The potential is not being realised. Why?
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
Why the Potential is Not Being Realised
• Too few people are using URIs as identifiers
– It’s partly our fault
• We don’t explain the benefits loudly enough
• We don’t make it sufficiently easy and worthwhile
• We’ve been in turmoil on technical issues
• And those that do use URIs as identifiers tend to
create new ones, rather than reuse existing ones
– This defeats the purpose of a universal naming
scheme
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
Problems We Need to Address
1) The concepts are too varied and confusing, and
they are not being marketed well
– The world perceives a Heinz 59 variety of URIs
– IRI, URN, URL, http:URI, XRI, WPN, TDB, ...
2) Reuse hard in practice
– No repositories to aid discovery
– No simple way to figure out what a given
identifier is supposed to identify
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
What We Need To Do
• Make the concepts easy to understand and apply
– Agree on one flavour of URI
– Promote the hell out of it
– Deprecate everything else
• Encourage reuse in every possible way
– Make it easy to discover and interpret identifiers
– Encourage them to be made public
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
Make http:URIs the flavour of choice!
• Already widely used in Topic Maps and RDF
– And, increasingly, elsewhere
• No longer subject to paralysing controversy
– TAG’s resolution of httpRange-14 issue allows any
http:URI (including slash http:URIs) to identify
anything
• Familiar to anyone who has used a web browser
– Having people type http://... will not be a problem
• Most importantly: They resolve easily when you
click on them
– So let’s exploit that fact...
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
Have them resolve to something useful!
• The most useful thing to resolve to would be a
descriptor
– definition, description, some other kind of indication
of what the identifier is intended to identify
– (machine-processable information would be a
useful “optional extra”)
• Allows users to know what the identifier “means”
– i.e., what it is intended to identify
– ... and decide whether it is appropriate for them to
use
• Also easy to discover using web search engines
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
A Proposal for Public Resource Identifiers
Three Key Principles:
1. A Public Resource Identifier (PRI – “pry”) is
– an http:URI that has been minted for the explicit
purpose of serving as an identifier
2. It resolves to a Public Resource Descriptor (PRD)
– that describes which resource (subject) it
identifies and states who minted it
3. ANYONE should be able to mint a PRI
– A bottom-up mechanism (anarchic, like the Web)
– Survival of the fittest (= the most trusted)
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
Sounds familiar?
• Essentially identical to “Published Subjects”
– Proposed by SC34 in 1999 as Public Subjects
– Refined within OASIS as Published Subjects
• Only major difference:
– The requirement to use http:URIs
• But also a restatement of basic Web Architecture principles
– Cool URIs don’t change
– http:URIs can identify anything
– http:URIs should resolve to something useful
• Does it matter what we call it?
– (Does it even need a new name?)
– “A rose by any other name would smell as sweet”
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
What’s in a Name?
• Would this rose by any other name smell as sweet?
• It’s a branding issue
– Does the name have useful / non-useful connotations?
• cf. “resource” and “subject”
– Can we create cool TLAs (if necessary)?
• pronouncable, depictable, available, distinguishable
The Paradigm
Published Subjects
Public Resource Identifiers
The URI
published subject identifier
public resource identifier
Abbrev. of the above
PSI (Ψ)
PRI (“pry”)
Referent of the URI
published subject indicator
public resource descriptor
Abbrev. of the above
PSI
PRD
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
A Call for Action: Incubator Group
• Let the W3C and SC34 get together to push PRIs
– The details can be hammered out in a few months
• Then bring OASIS on board
– (before even more vocabularies appear...)
• Approach other standards bodies, including
– SC32 (databases, meta data), SC36 (e-learning),
IFLA, and others (TBD)
• Let’s build a Semantic Superhighway together…
– I will be making a formal proposal shortly
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
The PRI Incubator Group
• A W3C activity with participation from ISO and
OASIS
• Chartered for < 12 months to
– refine and codify the Three Key Principles
– provide absolutely minimal recommendations for
• the form of the PRI
• the content of the PRD
– address issues of branding and outreach
• esp. naming and strategy for promulgating the paradigm
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
More on the PRI-XG
• Suggested participation
– 3 sponsors from W3C (TAG, SemWeb, ...)
– Invited international experts from ISO SC34
– Invited experts from OASIS (UBL, OpenOffice)
– Coordinator and team contact
• Suggested goals
– XG Report
– Possible fast-track as W3C Rec and ISO Technical
Report
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006
The Continuation of a Fine Tradition
• Diderot’s Encyclopédie (1751–1780)
– THE DESCRIPTION OF EVERYTHING
• Oxford English Dictionary (1857–1928)
– THE MEANING OF EVERYTHING
• Public Resource Identifiers (1999– )
– THE IDENTITY OF EVERYTHING
X
Steve Pepper – The Case for Public Resource Identifiers
IRW Workshop, Edinburgh, May 2006