1. NISO Virtual Conference 19 February 2014 Ralph Swick, W3C
The Web of Data
NISO Virtual Conference
19 February 2014
Ralph Swick, W3C

2. Agenda Data is changing our lives W3C’s traditional focus
Expanding scope of W3C’s data activities

3. Web has transformed our relation to computers and to data
A computer in every pocket
Apps leveraging context
geolocation and other sensors
social context (“I’m at the conference, too!”)
Change in the use of search
people search for answers, not sites
answers from aggregated data (Siri, Google Now, Wolfram Alpha)

4. Apps are using data from many sources
Social networking
Mobile devices
Sensors
Open data

5. Imagine…
A “Web” where
documents are available for download on the Internet
but there would be no hyperlinks among them

6. Data on the Web is not enough…
We need a proper infrastructure for a real Web of Data where:
data are available on the Web
accessible via standard Web technologies
data are interlinked over the Web
data can be integrated over the Web
This is Linked Data

7. Agenda Data is changing our lives W3C’s traditional focus
Expanding scope of W3C’s data activities

8. Semantic Web Core RDF data model RDF Schema vocabulary design
RDB2RDF relational DB export
SPARQL query
SKOS vocabulary description
OWL ontological inference
RIF rules interchange
LDP read-write Web of Data
POWDER description resources
GRDDL app-specific XML

9. Need for RDF schemas First step towards the “extra knowledge”:
define the terms we can use
what restrictions apply
what extra relationships are there?
“RDF Vocabulary Description Language”
the term “Schema” is retained for historical reasons…

10. Vocabularies
There is a need for “languages” to define such vocabularies
to define those vocabularies
to assign clear “semantics” on how new relationships can be deduced

11. SKOS
SKOS provides a simple bridge between the “print world” and the (Semantic) Web
Thesauri, glossaries, etc., from the library community can be made available
SKOS can also be used to organize, e.g., tags, annotate other vocabularies, …

12. Semantic Web/Linked Data Today
Standards are mature
some level of maintenance work is always needed
Server-side applications dominate
Commercial applications exist, e.g.:
direct integration/usage of linked data on the Web
consumption of other formats converted internally to a common format (RDF)

13. Challenge: leverage data in interoperable apps
Public, private, behind enterprise firewalls
From informal to highly curated
From machine readable to human readable
HTML tables, twitter feeds, local vocabularies, spreadsheets, …
Expressed in diverse data models
tree, graph, table, …
Serialized in many ways
XML, CSV, RDF, PDF, JSON, HTML Tables,…

14. The Linking Open Data Project

15. Linked Data Principles Is your data 5 Star?
Available on the Web in some format (i.e., use URI to access the data)
Available as machine-readable structured data (e.g., excel instead of an image scan)
As before, but using a non-proprietary format (e.g., CSV instead of excel)
All the above, plus use open standards (RDF & Co.) to identify things, so that people could point at your stuff
All the above, plus link your data to other people’s data to provide context

16. A Three Star Example

17. The importance of Linked Data
Provide a core set of data that applications can build on
stable references for “things”,
e.g.,
many many relationships that applications may reuse
a “nucleus” for a larger, semantically enabled Web!

18. Linked Data Platform (LDP)
Define an HTTP/RESTful based infrastructure to publish, read, write, or modify linked data
typical usage: data intensive application in a browser, application integration using shared data…
The infrastructure should be easy to implement and install
provides an “entry point” for Linked Data applications!
The work is nearing completion

19. RDF with HTML: RDFa
By adding some “meta” information, the same source can be reused
typical example: your personal information, like address, should be readable for humans and processable by machines
Some solutions have emerged:
add extra statements in microdata or RDFa that can be converted to RDF
microdata can be used for a (useful) subset of RDF
RDFa is, essentially, a complete serialization of RDF

20. schema.org
Schema.org is a cooperation of search engines (Bing, Google, Yahoo!, and Yandex)
It is a large vocabulary that they all understand
The terms are extracted from HTML5+microdata or HTML5+RDFa
the various partners use it for different purposes
it can be used by anyone outside of the search world!

22. Some things to remember when you publish data
Publish your data first, do user interfaces later!
the “raw data” can become useful on its own right and others may use it
you can add your added value later by providing nice user access
If possible, publish your data in RDF but if you cannot, others may help you in conversions
trust the community…
Add links to other data. “Just” publishing isn’t enough…

23. Some things to remember when you publish data (2)
Think about persistence and versioning
others may depend on the data you publish…
Be thoughtful about the URIs you choose
Try to avoid reinventing the wheel when choosing vocabularies

24. Some things to remember when you publish data (3)
Document your data, i.e., provide metadata
there are vocabularies to do this
Data Catalog Vocabulary (DCAT)
Vocabulary of Interlinked Datasets (VoID)
DCTERMS
vocabularies for licensing (Open Data Commons, government licenses)
this area is still very much in development…

25. Agenda Data is changing our lives W3C’s work on data integration
Expanding scope of W3C’s data activities

26. New work underway CSV on the Web Data on the Web Best Practices
Vocabulary management

27. What we are hearing CSV is everywhere Metadata is essential
can be huge data sets, not easily readable in a spreadsheet or Google refine
meaning of data not in machine-readable form
data is not necessarily used for web-scale integration but rather immediate usage
Metadata is essential
Conversion is an issue
European Commission Study on business models for Linked Open Government Data (BM4LOGD)

28. Linked Data Benefits (BM4LOD)
Flexible data integration
Streamlined internal processes
Where working relationships already exist, much easier to share
Linking reference collections; discovery of new relationships
Increase in data quality
More use of data internally brings errors to light
Use of open standards increases quality of system
New services
Cost reduction
Increased efficiency
Increase in data usage due to LOD enrichment

29. CSV on the Web How W3C can help
metadata vocabulary to describe CSV data (structure, reference to access rights, annotations, etc.)
metadata discovery (e.g., part of an HTTP header, special rows and columns, packaging formats…)
mapping content to RDF, JSON, XML
- The WG is planned for about 18 months to publish a REC, with the technical design being done in about a year, ie, end of 2014
- but the timeline is not yet finalized.
- The experiences of the RDB2RDF will be very helpful for the mapping part.

30. Best practices Document best practices for the data publishers
URI design, management of persistence, versioning
business models
use of core metadata vocabularies (provenance, access control, ownership)
Specific vocabularies
quality, application descriptions, …
- Quality and Granularity Description Vocabulary (what is the quality of the data, how frequently is it updated, does it accept user corrections).
Application description vocabulary (what does the application do, what problem does it help to solve, which data sets does it use).
The timeline is not yet finalized, the vocabularies-s should be available at the end of The best practices may take longer.

31. Vocabulary management: challenge
Interoperable vocabularies are key for (meta)data
At the moment, it is a fairly chaotic world…
many, possibly overlapping vocabularies
difficult to locate the one that is needed
vocabularies may not be properly managed, maintained, versioned, provided persistence…

32. Vocabulary management: how W3C can help
Provide a space where
communities can develop vocabularies (through, e.g., CGs, possibly WGs)
host vocabularies at W3C if requested
annotate vocabularies with a proper set of metadata terms
establish a vocabulary directory
The exact structure is still being discussed

33. Summary
Data-driven smart apps are one of the major growth engines for the worldwide software market.
We need to meet developers where they are.
5 Star Benefits of LOD
Greater efficiency, better provision of the task
Greater flexibility leads to lower costs for future projects
New services, new connections, new discoveries
Improved navigation within and between datasets
Others can build apps based on your data

34. Available specifications: Primers, Guides`
RDF Primer
OWL Guide
SKOS Primer
GRDDL Primer
RDFa Primer
The W3C Semantic Web Activity Wiki has links to all the specifications

35. These slides are in the Web at
/0219-NISO-RRS
with thanks to Ivan Herman, W3C and Phil Archer, W3C