linked data: the real web 2.0 (from 2008)
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Linked Data: The Real Web 2.0
Uche Ogbuji <uche@zepheira.com>17 June 2008, NYC
Hi. I’m Uche Ogbuji• Partner at Zepheira
• Web architecture & Semantic technology solutions
• Ask me about: START, 3D, Remix
• Longtime leader in XML, data integration and semantic technology
• Lead on key open specs & FLOSS, e.g.
• Jacquard Web development methodology
• Versa RDF query language
• 4Suite & Amara XML/RDF tools
Nigerian-American. Father. Husband. Poet. Entrepreneur. Engineer. Tech pundit. Footballer (“soccer”). Snowboarder. Skateboarder. Hip-Hopper.
The goal: enough Linked/Linking (Open) Data basics for the curious
But enough deep discussion for the initiated
A brief history...
• The Web, mid-1990s
• Big daisy chain of home pages. Not much need for context in hyperlinks.
• Sloppy was OK. Remember 404s?
• Then it started to get big. Portal wars, search engine wars, browser wars...
• Sloppy was starting to really hurt...
First wave solutions
• XML for the document weenies. RDF for die echten menschen
• Hey, if the W3C builds it, they will come
• Semantic Web FTW!
• Time to sort out the chaos of the Web. Context by formal declaration.
• Anyone here tried explaining OWL to Joe Webmaster?
Back to architecture
• Enter SOAP Web services: suddenly we had more pressing concerns
• Uh oh! There’s a cuckoo’s egg in the Web
• We fought back with REST
• Phew! Got that anti-cuckoo detection kit ready just in time
• Lesson learned: if we didn’t keep to the original, simple principles
What’s that lesson again?
• We think we know what makes the Web work so well
• We want others to understand, so we want to have suggestions and tools for them
• We’d better keep to the simplest suggestions and tools that could possibly serve our cause
Simplest that could possibly...
• So Semantic Web, right?
• You kidding? Ever tried to explain SemWeb to Joe Webmaster?
• So... REST, right?
• You kidding? A Ph.D. dissertation? Get Joe Webmaster the Cliff Notes
• OK. OK. I give up...
Back to history: Web 2.0
• Bored one day, The Weblog echo chamber dusted off some old Web tricks
• Enough smart developers came up with enough simple tools and suggestions to create a craze
• So is this a catastrophic distraction from what the Web really needs?
Say what?
• You make some modest enhancements to your site (the local). That’s all you need to worry about.
• You then roll in the global power of Web-enabled services: Mashups, feeds, user-generated content...
• ...Mumble...SEO...mumble...long tail...mumble...
• ...Profit
• What Webmastering Joe could resist that call?
But hey!But wait!
But SWEET!“Think global, act local” is all we needed from Joe
anyway, right?You know, to make a better Web????!!!
Web2: Web feeds
• RSS, Atom, JSON...
• For a bunch of non SemWebby guys Atom 1.0 community did a decent job
• Finally gives us a reasonably pervasive format for reading, with some true context retained
• A small step towards a machine-readable Web
• Small steps matter!
• Read the Web
Web2: User-generated content• Hey, isn’t this the write part of the read-write Web
we’ve been craving?
• Thank Wikipedia just for the psychological fillip for the non-techie: you too can write
• Sure forums technically offered that for ages, but Wikipedia carries an clear, broadcast message. It’s prime time.
• Write the Web
• Oh BTW Remember that Web of Trust thingie SemWebbers were chattering up years ago?
• Psssssst! We kinda really need that now. Thanks.
Web2: Mashups
• “So, like, all I have to do is focus on the sort of information I specialize in, and mark it up in clear context”
• “Yep. And other smart folks just combine it with other data in ways you never imagined”
• “OK, that’s worth paying some attention to Web data design”
Web2: Mashups
• Joe’s sophistication might end with mashing, but a good data architect can make meshes of mashes
• Remix and Re-purpose the Web
We’re not different from Web 2.0
• Vendor independent
• Scalable
• Extensible
• Multi-device friendly.
• It’s not just about the PC/Mac bowser, you know
We’re just Web 2.0, properly
Marketing command: What would Web 2 do?
Heresy maybe, but marketing matters, even when you’re just trying to do the right thing
Linked Data means just remembering 4 things
1. Use URIs as names for things
2. Use HTTP URIs so that people can look up those names.
3. When someone looks up a URI, provide useful information.
4. Include links to other URIs. so that they can discover more things.
From kernels of wisdom grow...
• Joe Webmaster can understand this, and probably remember this
• #3 and #4 are openings for clever types to push for more
•It’s all about the link, ya’ll
<a href...
• The granddaddy link
• The most pervasive link
• Limited for preserving context
• @rel, @type and such do help
• Just plain Limited.
XLink? Hlink?
• OK <a href is limited, but at least you can grasp it in minutes
• We like our snoozefest flame wars, eh?
• How many URI hashes/slashes can dance on the head of a pin?
• What is the link to the divine? Sophisticated Gnosis? Simpleton Chrestos? The 3-personed markup?
• Needless to say, not too many people are using XLink, HLink and friends
RDF
• RDF is in effect a linking technology
• <a xml:base=”Subject” href=”Object” rel=”predicate”>...
• Generally separate from described resources (not unlike XLink link-bases)
• Also a fairly heavy conceptual burden
• An unfortunate syntax is more prevalent than the useful model
Yes: <a href...
• Worse is better, folks
• Just a few careful conventions and we can squeeze a bit more out of it
• @rel conventions
• @type coordinated with core HTTP (media types, content negotiation, etc.)
• Let’s first see what we can build on that, then worry about the gaps
Clever types building on Linked Data
• Emphasize a particular set of conventions and tools for refining Linked Data
• HTTP usage such as content negotiation or 303s for linking to abstract resources
• Syntax layer usage such as RDFa and GRDDL
• Emphasize a particular set of sites as seeds for growing Linked Data
• DBPedia is the star
Kingsley’s four techniques
1. Handle Content Negotiation requests
2. <link rel=-"alternate"..../> (when HTML is requested)
3. GRDDL profile in <head/> plus <link rel="transformation".../> (when (X)HTML or XML is requested)
4. eRDF or RDFa (when HTML or (X)HTML is requested)
Note: Taken from a community posting. See Kingsley’s presentation for his own refinement of this...
What is LED?
• A community project to develop tools and architectural strategies to bring Sensible SOA to the Enterprise through data-driven applications
• You’ve heard of Linking Open Data? LED comes in when the data can’t always be so open
• You’ve heard of Enterprise 2.0 and Enterprise Mashups? LED comes in when you need such applications to outgrow the toy box
• Same relationship as with Linked Data to Web 2.0
Business context
• LED involves using tools to express business context as rich, reusable metadata (often RDF)
• LED involves using well-known data syndications tools to orchestrate data enriched with this context
• LED involves using formally expressed policy to control data flow and capture responsibility
Bridge to legacy
• Rather than the ERP-type play to replace legacy apps with a centralized super-model, LED focuses on wrapping and exposing data in those apps
• The exposed and contextualized data from source applications is integrated using basic Web technology
LED step by step
• Capture business context during analysis
• Capture business rules and policy during analysis
• Express these in simple, sharable, reusable formats made available to people as well as code (SKOS, Attempto-Controlled English, etc.)
• Map data models of existing applications to the expressed context (declarative data transform)
More LED step by step
• Architect Web integration layer around documented context
• Use mappings to drive Web-feeds from legacy apps to the integration layer (JSON, Atom, RDF, etc)
• Use lightweight so-called Web 2.0 kit to simplify browser access
Questions?
uche@zepheira.comhttp://zepheira.com
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