intro to linked data: context

An Introduction

toLinked Data

David Hyland-WoodUniversity of Mary Washington

Part 1 of 5Linked Data Context

Monday, May 16, 2011

Agenda

• Setting the scene

• What is Linked Data?

• RDF - A data format for the Web

• Data modeling without context

• URIs - Naming Things on the Web


Agenda

• Turtle - Human-readable RDF

• RDF/XML - RDF for XML pipelines

• Other RDF formats: RDFa, N3

• RDF Schema - Describing structure


Agenda

• Converting existing data into RDF

• Linked Open Data on the Web

• SPARQL - A query language for RDF

• Linked Data publishing options

• Building Linked Data applications


http://linkeddatabook.com/editions/1.0/

http://3roundstones.com/linking-enterprise-data/

Reading






Final Project

• Collect/convert/publish data about Fredericksburg

• UMW, restaurants, Liberty Town, parks/rec, music/bands, etc, etc.

• Whatever you want.

• Together, we will build one or more applications using that data.


Grades

• Grades will be based on class participation and completion of the final project.


A Process

PublishConvertDescribeNameModelIdentify


A Process

PublishConvertDescribeNameModelIdentify

Maintain


Settingthe

SceneMonday, May 16, 2011

shared innovation™

1970s 1980s 1990s

$ cat foo.txt | grep blah | sort

A neat little package Client-Server The Early Web

A HISTORY OF SILOS


shared innovation™

Web

Universal Client

Universal Connection

Universal Database

Logic and interlinking

Ubiquitous,reusable applications

URL Curation

of Data


0

10

20

30

40

50

60

70

80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Access per 100 population worldwide

1992

Mobile cellular subscriptionsFixed telephone linesInternet users


Data Inflation

Megabyte (MB) = 220

Gigabyte (GB) = 230

Terabyte (TB) = 240 1,000GB

Petabyte (PB) = 250 1,000TB

Exabyte (EB) = 260 or 1,000PB

Zettabyte (ZB) = 270 or 1,000EB

Yottabyte (YB) = 280 or1,000ZB


March of the Machines

“Information created by machines and used by other machines will probably grow faster than

anything else...

Only 5% of the information that is created is structured but this is changing as content

on the Web is increasing tagged.”

- Roger Bohn of University of California, San DiegoStudy on American Households


The painter... does not fit the paints to the world.He fits himself to the paint.

-- Paul Klee


17%

49%

16%

13%

4%

6 months12 months18 months24 monthsMore than 24 months

Acceptable ROI for IT


What isLinkedData?


The Web of Documents• A global network of linked documents

• A place where anyone can say anything about anything

• A vast collection of human-readable knowledge (and opinion)

• Documents are linked, but links are not qualified


The Web of Data• A global network of linked statements

• A place where anyone can say anything about anything

• A vast collection of machine-readable knowledge (and opinion)

• Statements are linked, and links are qualified


The Web of Data• Modeled for re-use using simple

statements

• Named using HTTP URIs for things and for documents

• Described using simple schema which can be remixed and extended

• Data published on the web in RDF


The Web of Data• Governments

http://data.gov/, http://data.gov.uk/ and others

• The BBChttp://www.bbc.co.uk/programmes/developers

• The New York Timeshttp://data.nytimes.com/

• The Library of Congresshttp://id.loc.gov/

• Facebookhttp://developers.facebook.com/docs/opengraphhttp://opengraphprotocol.org/


http://data.gov.uk

http://data.gov.uk

http://data.gov.uk

http://data.gov.uk

RDF:A data format for

the WebMonday, May 16, 2011

RDF is ...• Resource Description Framework

http://www.w3.org/RDF/

• A simple, powerful, data model

• Used to define relationships between things

• Designed to work with the architecture of the web

• The data model for the Web of Data




Allow anyoneto say anythingabout anything


http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?

id=1969-059A


http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1969-059A







id=1969-059A

NASA - NSSDC - Spacecraft - Detailstitle









id=1969-059A


23 November 2009published









id=1969-059A



15702size









id=1969-059A



Apollo 11 Command and Service Module

15702size













id=1969-059A




about

15702size













id=1969-059A




about

Web Pagea

15702size















id=1969-059A




about

Web Pagea Spacecrafta

15702size

















id=1969-059A




about


Apollo 11 Command and Service Modulename

15702size

















id=1969-059A




about



16 July 1969launched

15702size

















id=1969-059A




about




15702size

28801.0mass
















Spacecraft Name Mass Launched Launch Site

1969-018A Apollo 9 26801.0 1969-03-03 1

1969-030A Mariner 7 411.8 1969-03-27 1

1969-043A Apollo 10 28834.0 1969-05-18 1

1969-059A Apollo 11 Command and Service Module (CSM) 28801.0 1969-07-16 1

1969-059C Apollo 11 Lunar Module / EASEP 15065.0 1969-07-16 1


1970-029C Apollo 13 Lunar Module/ALSEP 15196.0 1970-04-11 1




id=1969-059A




about




15702size

28801.0mass

















1969-018A Apollo 9 26801.0 1969-03-03 1

1969-030A Mariner 7 411.8 1969-03-27 1

1969-043A Apollo 10 28834.0 1969-05-18 1








1969-018A Apollo 9 26801.0 1969-03-03 1

1969-030A Mariner 7 411.8 1969-03-27 1

1969-043A Apollo 10 28834.0 1969-05-18 1






ID Name

1 Cape Canaveral, United States

2 Tyuratam (Baikonur Cosmodrome), U.S.S.R

3 Xichang Space Launch Center


http://www.chinadaily.com.cn/en/doc/2003-10/15/content_272334.htm

http://www.chinadaily.com.cn/en/doc/2003-10/15/content_272334.htm


id=1969-059A




about




15702size

28801.0mass

















Spacecrafta



28801.0mass









Spacecrafta



28801.0mass

Cape Canaveral

Cape Canaveral, United States name

launchsite











Spacecrafta



28801.0mass

Cape Canaveral


launchsite

Resource











Spacecrafta



28801.0mass

Cape Canaveral


launchsite

Resource

Literal











Spacecrafta



28801.0mass

Cape Canaveral


launchsite

Resource

LiteralPredicate










Resources...• Represent things on the web, like web

pages — Information Resources

• Represent things not on the web, like people and places — Non-Information Resources

• Can represent anything at all

• Named using URIs (usually)

• May not have a name — Blank Nodes


Literal Values...• Are values to work with and show

users

• Can be just a string of text — Plain Literals

• Can have a language assigned to the them using ISO codes

• Can have a specific datatype assigned to them — Typed Literals


Predicates are...• Relationships between Resources

• Named using URIs

• Described in Schema(or vocabularies, or ontologies)


Apollo 11 Command and Service Module Cape Canaveral Cape Canaveral,

United States namelaunchsite

Statement or Triple










Statement or Triple




Subject Predicate Object

Statement or Triple





Statement or Triple

Statement or Triple



Spacecrafta



28801.0mass

Cape Canaveral


launchsite

LiteralPredicate

Resource











Spacecrafta



28801.0mass

Cape Canaveral


launchsite











Spacecrafta



28801.0mass

Cape Canaveral


launchsitehttp://.../1969-059A

http://.../Spacecraft

http://.../cape+cana...















Spacecrafta



28801.0mass

Cape Canaveral


launchsitehttp://.../1969-059A

http://.../Spacecraft

http://.../cape+cana...

N 28° 27' 31''latitude

W 80° 31' 59''longitude














Simple Rules for Merging• URIs name the resources we are

describing

• Two people using the same URI are describing the same thing

• The same URI in two datasets becomes one URI with all of the properties from both datasets

• RDF data can use URIs from many different websites


Simple Rules for Merging• Graphs from several different sources

can be merged

• Resources with the same URI are considered identical

• No limitations on which graphs can be merged


Any RDF can be merged with any

other RDF


RDF...• is a Graph data model

XML is a tree data modelRDBMS is a table data model

• can be easily distributed

• is easily mergeable

• can say anything about anything

• is not newthe spec is from 1999the idea, EAV, stems back to the late 1960s


Thanks to

• Rob Styles, Talis Group Ltd for his CC-BY licensed “Two Day Introduction to the Web of Data” slides and spacecraft example data.


This work is Copyright © 2010 David Hyland-WoodBased partially on CC-BY licensed content Copyright © 2010 Talis Systems Limited by Rob Styles. It is licensed under the Creative Commons Attribution 3.0 Unported License.Full details at: http://creativecommons.org/licenses/by/3.0/

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intro to linked data: context

Education

web of data governments

web data modeling

open data

existing data

extended data

linked data applicationsmonday

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http uris