Re-usable metadata, re-usable content

UKOLN is supported by: Re-usable metadata, re-usable content Paul Walk Technical Manager [email_address] A centre of expertise in digital information management www.ukoln.ac.uk

harvesting, searching, syndicating

options for metadata and content:

the lines can be blurred

search engines also harvest!

your metadata may be my content

metadata content harvestable searchable ✓ ✓ syndicable ✓

being harvestable (1)

Open Archives Initiative

OAI-PMH

repositories

OAI-ORE

aggregators:

Intute Institutional Repository Search

currently harvesting eprints metadata records from 88 institutions

planning to explore the harvesting of metadata for:

images

learning objects

other media.....

MLA’s Discover Service

your content is of interest to other domains

being harvestable (2)

what is your metadata record actually going to point to?

more than one item of content?

a ‘jumping off’ page?

is this consistent?

what metadata format are you going to use?

is it commonly supported?

are you using it correctly? (you’d be surprised.....)

where/how is your metadata going to be used?

this is necessarily out of your control!

being searchable (1)

exposing your content to search engines

search engine optimisation (SEO)

make it easy for the search engines

have content people want

make it eminently linkable

Google is your friend!

SiteMaps - describe your content in ways Google can understand

OAI-PMH interface can be treated as a SiteMap

Z39.50

from the library domain

allows the target to participate in a cross search

very mature, very widely deployed

not a web protocol

SRU

web-ified Z39.50

ReSTful

Common Query Language (CQL)

SRW

as above, but for heavier SOA/Web Services use

OpenSearch

piggyback on RSS/Atom

search portals

community portals

institutional portals/VLEs

be syndicable, enable re-use by 3rd parties

consider RSS (and the Atom syndication format)

in some ways the lingua franca of Web 2.0

machine and human friendly

surprsing how much content lends itself to this structure

RSS2.0 can also ‘enclose’ binary data

syndicating podcasts

“ the coolest use of your data will be thought of by someone else”

be mashup friendly:

addressable content

cool URLs

simple formats

aspire to APIs that need no documentation!

human and machine interfaces (1)

they’re completely different....right?

well, not necessarily

RSS!

OAI-PMH with a CSS stylesheet referenced from the XML

human and machine interfaces (2)

‘ screen-scraping’ is back in fashion

plain old semantic HTML (POSH)

linked-data (the semantic web with a small ‘s’)

the web of data is imminent!

future design: taking a REST from service provision

the resource -oriented-architecture

ReST:

resources with cool URLs

4 HTTP verbs: get, put, post & delete

CRUD for the Web (create, retrieve, update, delete)

make everything addressable with URLs

be cool!

make the URLs persistent

make them human-parsable

e.g.

http://www.myserver.com/gallery/collections/pictures/image_0001.jpg

is better than:

http://www.myserver.com/gallery.php?collection_id=7&item_id=0001

my suggestions

using web protocols

make content addressable - and persistently so

reduce barriers to third-parties developing other (competing!?) UIs

are our UIs really just ‘gateways’ to information (implying that there is a wall around that information)

making the machine APIs the heart of our services

a good design principle is to use the machine API as the API used by our own user-interfaces

we just can’t know for sure all the ways in which our information services might be used

acknowledgements

in preparation for this presentation, I blogged about giving this presentation and asked my readers:

“ Aside from the obvious stuff like OAI-PMH, Google, RSS, what should I be talking about? Persistent identifiers? Cool URLs? Any other suggestions?”

6 responses - all containing great suggestions which I have incorporated into this presentation, from the following people:

Jim Downing, Owen Stephens, Ian Ibbotson, Pete Johnston, Mike Ellis

thanks!!

you can read all of the comments, and find links/addresses for these people on my blog at:

http://blog.paulwalk.net/2008/02/11/making-digitised-content-available-for-searching-and-harvesting/

comments

Ian Ibbotson said:

It’s very hard to engineer a consistent search user interface when half the metadata refers to the actual digital artefact, and half to a front page. It’s useful to have both links, as you can then negotiate with providers if they feel you need to go through a front page for stats and marketing....

Pete Johnstone said:

a shift away from the “repository” towards the “collection” or “collections” (which I think is the consequence of a more “resource-oriented view”)

Owen Stephens said:

Integration of resources into the wider web - e.g. LoC experiment with Flickr to expose content. Many projects in this area create a new silo of material that is hidden from the wider web [...] reusable metadata as well as objects.