Persistent Identifiers for the "Real Web" The Real Web

(1)

Persistent Identifiers for

the "Real Web"

David Wood Eric Miller

1

(2)

The “Real Web”

You

Me

The conference

Your laptop

2

(3)

cover

Moby Dick

is a

3

cover

Moby Dick

is a

has author

Herman Melville

depiction

(4)

date

1851

cover

Moby Dick

is a

has author

Herman Melville

depiction

3

date

1851

Films

adapted to

The Sea Beast

title

date

1930

1956

1998

1926

Moby Dick

cover

Moby Dick

is a

has author

Herman Melville

depiction

(5)

date

1851

Films

adapted to

The Sea Beast

title

date

1930

1956

1998

1926

Moby Dick

cover

Moby Dick

is a

soundtrack

poster

has author

Herman Melville

depiction

3

We (almost)

do this on the

World Wide Web

(6)

5

1970s

1980s

1990s

$ cat foo.txt | grep blah | sort

A neat little package Client-Server The Early Web

(7)

The Next Great Leap

7

Web of Data

Extending the

Universal Client

Expanding the

Universal Connection

Ubiquitous, reusable applications

(8)

Web of Data

Extending the

Universal Client

Expanding the

The Next Great Leap

7

Web of Data

Extending the

Universal Client

Expanding the

Providing the

Universal Database

(9)

Web of Data

Extending the

Universal Client

Expanding the

Providing the

Universal Database

Explaining the Logic

The Next Great Leap

7

Web of Data

Extending the

Universal Client

Expanding the

Providing the

Universal Database

Explaining the Logic

The Next Great Leap

(10)

•

PURLs provide permanent URLs for

information resources on the World Wide

Web.

•

PURLs work by simple HTTP redirection.

PURLs

8

•

The Online Computer Library Center

(OCLC) has run a public PURL service since

1995 at

http://purl.org

.

•

Used by others for private PURL services

(libraries, Internet namespaces, government,

some corporations).

•

Open Source, open standards.

(11)

Change in Host

One PURL

Change in Hosting

Organization

Evolution

10

PURLs

•

You might already be using PURLs:

Mediawiki has a shorthand syntax for PURLs.

[[purlnet:scape]]

http://purl.org/NET/$1

(12)

I want to find Dave’s blog

PURL server

Example:

Find an information resource

12

Example:

Find an information resource

PURL server

No problem, go to

(13)

Client

PURL

Server

Resource

Server

GET PURL “Found” URL Resource GET URL HTTP 302

Simple Redirection

14

Other Persistent

Identifier Schemes

Scheme

Community

DOI

Publishers

LSID

Life sciences

INFO URIs

Libraries, publishers

(14)

•

Use of URIs as identifiers grounds your

scheme into the Web.

- PURLs do this

- DOIs and INFOs partially do

- LSIDs don’t.

Scaling

16

•

“PURLs provide one level of indirection, just

like a single value DOI name”

- Not any more.

•

“PURL servers don't know about each other”

- Federation coming soon.

(15)

•

Zepheira and OCLC rewrote the PURL server

from scratch to:

- Modernize the code

- Create a wider Open Source community

- Add some new features

•

We have a particular interest in supporting

permanent Semantic Web URIs.

PURLs for Real-World

Resources

18

•

The new PURL server allows the creation of

PURLs with these HTTP responses:

301 Moved Permanently

302 Found

303 See Other

307 Temporary Redirect

404 Not Found

410 Gone

Resources

(16)

•

PURLs with these HTTP responses:

301 Moved Permanently

302 Found

303 See Other

307 Temporary Redirect

404 Not Found

410 Gone

Resources

20

•

PURLs with these HTTP responses:

303 See Other

Used to identify

physical

and

conceptual

resources

Resources

(17)

Client

PURL

Server

GET PURL

“See Also” URL

This allows clients to automatically

resolve Semantic Web identifiers

without confusing them with

information resources.

HTTP 303

Resources

Client may choose to follow the link

22

I want to find out about Moby Dick

PURL server

Example:

(18)

PURL server

1) Moby Dick is a concept, not a particularinformation resource. 2) You may find out more about it at http://en.wikipedia.org/wiki/Moby_Dick

Example:

Resolve a conceptual resource

(19)

(20)

Best Practices:

Baby Steps

•

Identify resources by URIs.

•

Use “See Also” PURLs to ensure

cross-boundary data integrity.

•

Don’t reinvent the wheel: Reuse common

public and partner URIs before minting your

own.

28

Best Practices:

Next Steps

•

Share a PURL service or use more than one.

•

Coordinate at the information space level, not

the code or even API levels.

•

Local control, global access.

(21)

Running and Leaping

•

Experiment with Active PURLs.

•

An Active PURL participates in the provision

of metadata about resources it represents.

•

Come talk to us later.

30

•

http://purlz.org/

•

http://purl.org/

- Documentation, source code, mailing lists

•