ISWC GoodRelations Tutorial Part 4

transcript

The Web of Data for E-Commerce in Brief

A Hands-on Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey

October 25, 2009

Westfields Conference Center near Washington, DC, USA

Martin Hepp Universität der Bundeswehr München, Munich, Germany

Richard Cyganiak Digital Enterprise Research Institute (DERI), Ireland

08:30-10:30 Overview and Motivation: Why the Web of Data is Now 30’

Quick Review of Prerequisites 15’ The GoodRelations Ontology: E-Commerce on the Web of Data 75’

10:30-10:45 Coffee Break

10:45-12:30 RDFa: Bridging the Web of Documents with the Web of Data 45’

Expressing GoodRelations in RDFa: A Running Example 30’ GoodRelations – Advanced Topics 30’

12:30-13:30 Lunch Break

13:30-16:00 Hands-on Exercise: Annotating a Web Shop 60’

Querying the Web of Data for Offerings – SPARQL 15’ Querying the Web of Data – Exercises 15’

16:00-16:30 Coffee Break

16:30-18:00 Publishing Semantic Web Data: Make Your RDF Available 30’

Yahoo SearchMonkey and Yahoo BOSS 45’ Discussion, Conclusion, Feedback Round 15’

Logistics

SPARQL

Query Language

Endpoint Specification

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SPARQL: Query Language Specification

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http://www.w3.org/TR/rdf-sparql-query/

SPARQL Query Structure

# comments

PREFIX gr:<http://purl.org/goodrelations/v1#>

SELECT ?var1 ?var2 WHERE {?var1 rdf:type gr:Offering. ?var1 gr:validThrough ?var2. FILTER (?date < "2009-05-25T00:00:00Z"^^xsd:dateTime)}

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SPARQL: Matching Literals

PREFIX xsd:<http://www.w3.org/2001/XMLSchema#>

SELECT ?v WHERE { ?v ?p "abc"^^xsd:datatype }

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SPARQL: Matching Strings

PREFIX dc: <http://purl.org/dc/elements/1.1/>

SELECT ?title

WHERE { ?x dc:title ?title

FILTER regex(?title, "^SPARQL")

^= Starts with

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SPARQL Query

# find expired offerings:

SELECT ?o, ?date WHERE {?o rdf:type gr:Offering. ?o gr:validThrough ?date. FILTER (?date < "2009-05-25T00:00:00Z"^^xsd:dateTime)}

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SPARQL Query

# find label for UPC/EAN "0001067792600“

PREFIX xsd:<http://www.w3.org/2001/XMLSchema#>

SELECT ?uri, ?label WHERE {?uri rdf:type gr:ProductOrServiceModel. ?uri gr:hasEAN_UCC-13 "0001067792600"^^xsd:string. ?uri rdfs:label ?label}

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Quizzes

• Why is it important to use the OPTIONAL

clause for patterns that cannot be

assumed to be found?

• What is a Semantic Sitemap?

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Publishing Data on the Semantic Web

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Publishing RDF Data on the Web

• Publishing RDF/XML files

• RDFa - Embedding RDF in XHTML

• dataRSS

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Step 1: Publish File

Save the RDF/XML file under the filename

• semanticweb.rdf

in the root directory of your Web server so

that it becomes available as

• http://example.org/semanticweb.rdf

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Point to RDF/XML from HTML/XHTML

• Add a link element pointing to this file to

the header of your main Web page (or

other pages, too):

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<html lang="en"> <head> <title></title> <link rel="meta" type="application/rdf+xml" title="RDF/XML data for ***your company name***" href="http://www.example.org/semanticweb.rdf" /> </head> ...

Notify Semantic Web Search Engines

To do so, simply paste the URI

• http://example.org/semanticweb.rdf

into the respective fields of the following

submission pages:

• http://pingthesemanticweb.com/

• http://sindice.com/main/submit

• http://swoogle.umbc.edu/index.php?

option=com_swoogle_service&service=submit

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Server Configuration

• Rewrite

– http://example.org/semanticweb to

– http://example.org/semanticweb.rdf

• Correct media type rdf+xml

– The content type (media type) of the file

returned must be set correctly to "rdf+xml".

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Content Negotiation

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Web Page

HTML/XHTML

Meta-Data

RDF/XML

Server

http GET

Returns

Web Page

HTML/XHTML

Meta-Data

RDF/XML

Server Configuration

On Appache servers, simply edit

the .htaccess file: #Rewrite rule to serve RDF/XML content from the

vocabulary URI

RewriteRule ^semanticweb$ semanticweb.rdf

#Directive to ensure *.rdf files served as appropriate content type

#if not present in main apache config

AddType application/rdf+xml .rdf

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Publishing RDF/XML Data on MS IIS Platforms

• Ionics Isapi Rewrite Filter for IIS 5.0 and IIS 6.0

– http://iirf.codeplex.com/

• Microsoft URL Rewrite Module for IIS 7.0

– http://support.microsoft.com/kb/324064

(Thanks to Christophe Debruyne and Robert

Meersman for the hint!)

• ModRewrite

– http://www.micronovae.com/ModRewrite/

ModRewrite.html (Thanks to Sergio Fernández for the link!)

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Semantic Sitemaps

• Efficient means of telling a Semantic Web

search engine which RDF files are

available

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http://sw.deri.org/2007/07/sitemapextension/

Additional Information

• Cool URIs for the Semantic Web, W3C

Interest Group Note 03 December 2008

http://www.w3.org/TR/cooluris/

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RDFa: Bridging the Web of

Documents with the Web of Data

Martin Hepp

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Learning Goal

• Understand the data quality problems that

can result from the „naive“ Semantic Web

• Understand the RDFa syntax for

embedding RDF data into XHTML

documents

• Be able to express GoodRelations data in

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Data Redundancy and Data Quality Problems

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Addresses

Copy of

Addresses

Copy of

Addresses

Addresses Addresses

Data Redundancy in the Semantic Web

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Web Page

HTML/XHTML

Meta-Data

RDF/XML

Web Page

HTML/XHTML

Meta-Data

RDF/XML

Embedding RDF in XHTML

• Being able to represent meaning and rendering

information in a single document

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Server

http GET

Returns

XHTML +

Resource Description Framework

in attributes

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What is RDFa?

• From the Web of Documents' point-of-

view: a set of new (X)HTML attributes to

express metadata within (X)HTML

• From the Web of Data point-of-view: a

serialization format for RDF (such as RDF/

XML, etc.), where the RDF triples are

"embedded" into (X)HTML

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Yahoo SearchMonkey

Currently considers RDF data only if

• submitted via the (proprietary) dataRSS

feed format or if

• embedded inside XHTML pages via

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http://www.ebusiness-unibw.org/tools/rdf2datarss/

RDF in Attributes

<h1 property="dc:title">GoodRelations

RDFa minimal example</h1>

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Subject – Predicate – Object

• @about (URIorSafeCURIE) … for setting

the subject of a statement

• @typeof (CURIEs) … for setting the

type(s) of a resource (syntactic sugar)

• @href/@resource (URIorSafeCURIE) …

for setting the object of a statement

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• @property (CURIEs) … for relating a

resource to a literal value, that is, for

datatype properties

• @rel/@rev (reserved word | CURIE)+ …

for relating a resource to another resource,

that is, for object properties

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• @content (CDATA) … for setting a literal

object value

• @datatype (CURIE) … for the datatype of

a literal object value - if not specified, then

the default value is xsd:string

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DOCTYPE

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd"><html xmlns="http://www.w3.org/1999/xhtml"<head profile="http://www.w3.org/1999/xhtml/vocab">

<title>GoodRelations RDFa minimal example</title></head>(…)

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Example - Markup

• http://www.w3.org/TR/xhtml-rdfa-primer/

alice-example.html

• Install Operator on FF

• Debug page

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RDFa: Simplistic Usage Reusing existing text and values at their original position

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RDFa: Snippet Style Embedding additional meta-data in the same document,

but detached from the human-readable content

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RDF2RDFa Tool: Snippets

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http://www.ebusiness-unibw.org/tools/rdf2rdfa/

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Quizzes

• Why is RDFa important to simplify the

creation of Semantic Web content?

• How does RDFa contribute to a better

quality of Semantic Web data?

• What is the main principle of RDFa?

• Name the key elements and give a simple

example of using RDFa.

Hands-on Exercises: Creating,

Publishing, and Querying

Martin Hepp

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Step-by-Step (1) • Data Sources

– Form-based data entry

– RDBMS

– XML, e.g. BMEcat

– CSV

– Google CSV, RSS 1.0,

RSS 2.0

• Amount of Detail and

Data Model

– What shall be included?

– How shall the type of

products be represented?

• Data Delivery Options

– RDFa: Embedding meta-

data in XHTML

– RDF/XML: Extra file

– dataRSS: Yahoo feed

format

Step-by-Step (2)

• Update Mechanism & Data Management

– PHP on demand

– Script-based data dump

• Publishing the Data

– Server configuration

– Notifying Semantic Web crawlers, Yahoo, …

– Semantic Sitemaps

• Applications

GoodRelations Annotator

http://www.ebusiness-unibw.org/tools/goodrelations-annotator/

osCommerce Extension

http://code.google.com/p/goodrelations-for-oscommerce/

Joomla/VirtueMart Extension

http://code.google.com/p/goodrelations-for-joomla/

Google Product Feed Converter

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http://tr.im/sLcX

BMEcat2GoodRelations

• Converts complete catalogs from the popular

BMEcat XML Schema into GoodRelations

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http://www.ebusiness-unibw.org/tools/bmecat2goodrelations/

GoodRelations in MediaWiki

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http://www.ebusiness-unibw.org/wiki/RDFaInMediaWiki

GoodRelations in Oxid eSales

• Popular shop

software

• Free recipe for adding

GoodRelations,

developed by Daniel

Bingel

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http://www.ebusiness-unibw.org/wiki/GoodRelations4Oxid

GoodRelations Validator

http://www.ebusiness-unibw.org/tools/goodrelations-validator/

GoodRelations CookBook

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http://www.ebusiness-unibw.org/wiki/GoodRelations#Recipes_and_Examples

Task 1

• Use the GoodRelations Annotator to

create a description for your business or a

business that you know.

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Task 2

• Using Turtle & GoodRelations, describe the

following business.

– Miller Tax Consulting Inc., having two stores, selling

office supplies and tax consultancy

• Convert the Turtle to RDF/XML and validate it.

• Convert the RDF/XML to RDFa using

RDF2RDFa and paste it into a page of your

choice.

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Task 3

• Query the SPARQL endpoint at

http://loc.openlinksw.com/sparql

for the product properties and values for the

product with the EAN/UPC code

8714574993836.

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Thank you.

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ISWC GoodRelations Tutorial Part 4

Technology