Publishing and Interacting with
Linked Data
Roberto Garcia, Josep Maria Brunetti,
Antonio López-Muzás, Juan Manuel Gimeno, Rosa Gil
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
HCI & Data Integration Research Group
Universitat de Lleida, Spain
Overview
• Rhizomer
Platform for Linked Data publishing
(also Semantic Data)
–Data access
• Read (LinkedData / SPARQL)
• Write (Semantic FORMS + HTTP PUT/POST/DEL)
–Data sources
• Jena (File, MySQL, Postgres), Virtuoso, OWLIM,…
–Interaction
• Overview: Navigation bars
• Filter: Facets
• Details: HTML+RDFa, Interaction Web Services
(map, timeline,…)
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Architecture
• Server part:
– REST interface over repository
• GET: URI (LinkedData) or SPARQL Query
• PUT/POST/DELETE: data management
Rhizomer
Metadata
Store
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
DEL
POST
edit delete
PUT
GET
search new
Architecture
• Scope of GET operations:
– Concise Bounded Description (CBD) +
rdfs:labels for all selected resources
• Scope of POST/PUT/DEL operations:
– Concise Bounded Description
• DESCRIBE queries by default
– Facilitate browsing heterogeneous data
– Without a priori knowledge
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Architecture
• DESCRIBE http://rhizomik.net/~rosa:
CBD(…~rosa) = Fragment A U rdfs:labels
http://...vcard#work
http://...rdf#type
Rosa Gil
http://...vcard#Street
Jaume II, 69
http://...vcard#ADR
http://...vcard#Locality
http://...rdfs#label
http://rhizomik.net/~rosa
Lleida
http://...onto#affiliation
http://...rdf#type
http://...rdf#type
http://www.udl.cat
http://...onto#Professor
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
http://...onto#University
Fragment A
Architecture
<s5t:Audio rdf:about="http://www.segre.com/audio/20070323-bm.mp3">
<dc:title>Butlletí Migdia</dc:title>
<dc:date>2007-03-23</dc:date>
<s5t:genre rdf:resource="&srs;11000000"/>
<s5t:transcriptResource>
http://www.segre.com/audio/20070323-bm.xml
</s5t:transcriptResource>
</srt:Audio>
http://www.segre.com/ audio/ 20070323-bm.mp3 a Audio
RDF2HTML
title
date
genre
transcript
Butlletí Migdia
2007-03-23
politics
http://www.segre.com/audio/20070323-bm.xml
Referrers
http://rhizomik.net/.../NewsCodes-SubjectsOnto#11000000 a Subject
label
description
politics
Local, regional, national and international exercise of power, or
struggle for power, and the relationships between governing bodies
and states.
Referrers
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
GET 
RDF2HTML
Interacting
• Until now, Rhizomer like other Linked Data
publishing tools…
– HTML+RDFa and content negotiation
– Useful for computers, but also for human users?
• User tests:
– Typical questions:
• Where do I start?
• Where do I go now?
• What is this data about?
– What do we offer?
• Text search, type URI, SPARQL query,…
…but they do not answer end-users needs
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Interacting
• Example: What to do with DBPedia?
– 3.5 million things described
• Ontology: 257 classes y 1276 properties
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Interacting
– DBPedia main page does not provide too many clues...
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Interacting
• SPARQL Endpoint:
– select distinct(?c) (count(?i) as ?n)
where {?i a ?c} order by desc(?n)
c
n
http://www.w3.org/2002/07/owl#Thing
1668503
http://www.w3.org/2004/02/skos/core#Concept
632607
http://www.opengis.net/gml/_Feature
571764
http://dbpedia.org/ontology/Place
462349
http://dbpedia.org/ontology/Person
363751
http://dbpedia.org/ontology/Work
355100
http://dbpedia.org/ontology/PopulatedPlace
340443
http://dbpedia.org/ontology/Settlement
304370
http://xmlns.com/foaf/0.1/Person
296595
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
http://dbpedia.org/ontology/Species
168575
Interacting
• Simple search
– What to type?
– A URI? URI label?
–…
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Interacting
• Advanced search:
– iSparql
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Information Architecture
• Proposal: adapt data interaction patterns [Shneiderman]
and Information Architecture components [Morville]
– Data structure: automate IA components
– Scalable, dataset independent
• Interaction Patterns / IA Components
– Overview --> navigation bars, site map
• Main classes (topics) and their organisation
– Zoom & Filter--> facets, breadcrums
• Main properties and values, filter
– Details --> HTML view, Object-Action Paradigm
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Navigation Bars
– Get hierarchical structure for dataset ontologies
– For each class
•
•
•
•
URI
Label
# instances
Subclasses list
– Flatten to desired # levels and elements / level
• Classes and namespaces whitelist and blacklist
– Algorithm:
• When there is room, divide class with most instances
• When too many options, group classes with less instances
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Navigation Bars
7 elements in “Species” submenu:
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Navigation Bars
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Navigation Bars
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Navigation Bars
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Navigation Bars
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Navigation Bars
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Navigation Bars
Navigation bar provides overview for DBPedia…
…but what to do with 12.334 birds now?
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Facets
• Pre-compute list of facets for each class
– Properties used in dataset instances descriptions
– Facet metrics: frequency, #different values, more
common value cardinality, entropy,…
• DBPedia Birds case:
– http://dbpedia.org/ontology/Bird 12334 instances
– 226 different properties
• http://dbpedia.org/ontology/kingdom, 100%, 3 values,
6846 (Animalia),…
• User unfolds facet, show 5 +common values
– Filter, get more…
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Facets
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
AI Components
Facets
• Order facets by "utility” (work in progress):
– Prefer common properties, high frequency
– For values cardinality, discard extreme cases:
• Just 1 value for the property
• All different values, i.e. max. value cardinality = 1
– Prefer properties that evenly divide results,
higher entropy
Wine (Wine Ontology)
Property
hasFlavor
Entropy
0.918434
Value
Moderate
Strong
Delicate
Instances
28
15
10
hasSugar
0.556416
Dry
Sweet
OffDry
43
6
4
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Interaction
Object-Action
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Interaction
Object-Action
• Given a resource (object)…
determine available services (actions)
• Services descriptions:
– endPoint: service location
– hasInput: ASK SPARQL Query Template
• Service applicable to any resource ASK is true
– hasOutput: output content type
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Interaction
Object-Action
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Conclusions
• Navigation menus 
– dataset classes (topics) overview
• Facets 
– per class properties and values overview, filter
• Details 
– Generic view (HTML) + specific (map, timeline…)
• Users build queries without
SPARQL or dataset structure knowledge
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Future Work
• Facets:
– type dependent facets (number ranges, dates,…),
inverse properties, facets for facet values,…
• Other IA components: sitemap, breadcrumbs,…
• Assisted metadata edition
– Recommend properties and values based on
available ontologies and values
• More interaction services
– Calendar
– Plot…
WIMS’11 Conference, May 25th 2011, Sogndal, Norway
Thank you for your attention
More details: http://rhizomik.net/rhizomer
Contact: Roberto Garcia ([email protected])
HCI & Data Integration Research Group
Universitat de Lleida, Spain