This document describes Linked Open Data services that provide "is a" relationship queries over normalized DBpedia data. It discusses how DBpedia triples are converted to a new vocabulary and graph structure to support flexible querying of entity types, categories, and hierarchical relationships. Concise XML and JSON responses are returned for queries on specific graphs or across all graphs, with optional triple patterns included.

1. LINKED OPEN DATA
SERVICES
Is a “cat” a “mammal”? … true
Is a “lizard” a “reptile”? … true
Is a “cat” a “reptile”? … false
Is a “lizard” an “animal”? … true
…..

2. Four types of “IS A” query
• Shallow query TO rdf:type: “Cat” is a “Animal”?
• Is a “Cat” -> rdf:type -> http://dbpedia.org/ontology/Animal
• Deep query THROUGH rdf:type: “Cat” is a “Eukaryote”?
• Is a “Cat” -> rdf:type -> http://dbpedia.org/ontology/Animal
• “Animal” -> rdfs:subClassOf -> http://dbpedia.org/ontology/Eukaryote

3. Four types of “IS A” query
• Shallow query TO dcterms:subject: “Cat” is a “Feline”?
• Is a “Cat” -> dcterms:subject ->
http://dbpedia.org/resource/Category:Felines
• Deep query THROUGH dcterms:subject: “Cat” is a
“Felid”?
• Is a “Cat” -> dcterms:subject ->
http://dbpedia.org/resource/Category:Felines
• http://dbpedia.org/resource/Category:Felines -> skos:broader ->
http://dbpedia.org/resource/Category:Felids

4. CONVERT TRIPLES TO
NEW VOCABULARY
Re-link the Linked Data

5. Ontology
Resource
Category
Resource
Term
skos:broader
rdfs:subClassOf
dcterms:subject
Category
Resource
rdf:type
Ontology
Resource
Structured Hierarchy
Wikipedia Categories
Original Graph from DBPedia.org

6. Normalize Labels for Search
• http://dbpedia.org/page/United_States
• “united states”
• http://dbpedia.org/ontology/PopulatedPlace
• “populated place”
• http://dbpedia.org/class/yago/CountriesBorderingTheAtlanticOcean
• “countries bordering the atlantic ocean”
• http://dbpedia.org/resource/Category:Former_British_colonies
• “former british colonies”
Term /
Resource
rdfs:label
String:
Label

7. Update Types to Vulcan Vocabulary
prefix: halo-uri http://halo.vulcan.com/lod/2013/11/isa-vocabulary#
• http://dbpedia.org/page/United_States
• halo-uri:term
• halo-uri:term-id
• http://dbpedia.org/ontology/PopulatedPlace
• halo-uri:rdf-type
• http://dbpedia.org/resource/Category:Former_British_colonies
• halo-uri:wikipedia-category
Term /
Resource
rdf:type
Halo
Vocabulary

8. Add “Is A” Connection for Graphs
prefix: halo-uri http://halo.vulcan.com/lod/2013/11/isa-vocabulary#
• http://dbpedia.org/page/United_States
• halo-uri:isA http://dbpedia.org/ontology/Place
• http://dbpedia.org/page/United_States
• halo-uri:isA http://dbpedia.org/resource/Category:Republic
Term
halo-uri:isA
Type,
Category,
or Graph

9. Add “Is A” Connection for Ontology
prefix: halo-uri http://halo.vulcan.com/lod/2013/11/isa-vocabulary#
• http://dbpedia.org/page/United_States
• halo-uri:isA http://dbpedia.org/ontology/Place
halo-uri:isA
Term
Ontology
Tree
Ontology
Tree
Ontology
Tree
Ontology
Tree
Place
Populated Place
Country
Thing

10. Add “Is A” Connection for Categories
prefix: halo-uri http://halo.vulcan.com/lod/2013/11/isa-vocabulary#
• http://dbpedia.org/page/United_States
• halo-uri:isA http://dbpedia.org/resource/Category:Republic
Term
halo-uri:isA
Category
Tree
Category
Tree
Countries
Republics
“Is A” connections
not applied higher up
category tree
Category
Tree
Political Theories
Category
Tree
Philosophies

11. Search Terms and Context
New Graph with Links to DBPedia.org
Halo
type
Halo
type
Ontology
graph
Halo
label
Term
halo-uri:isA
Halo
type
Category
graph
Custom
graph
replaces
hierarchy
Halo
label

12. Ontology
Resource
Category
Resource
Term
skos:broader
rdfs:subClassOf
dcterms:subject
Category
Resource
rdf:type
Ontology
Resource
Structured Hierarchy
Wikipedia Categories
Original Graph from DBPedia.org

13. EXAMPLE: 1
Query TO and THROUGH rdf:type

14. Query TO and THROUGH rdf:type
• Is a “cat” a “mammal”?
• Is a “cat an “animal”?
Cat
halo-uri:isA
• Is a “lizard” a “reptile”?
Anima
l
• Is a “lizard” an “animal”?
Lizard
Mammal
halo-uri:isA
Reptile

15. Query TO and THROUGH rdf:type
• Is a “cat” a “reptile”?
• Is a “cat an “animal”?
Cat
halo-uri:isA
Reptile
Cat
halo-uri:isA
Anima
l

16. Query TO and THROUGH rdf:type
• Is a “cat” a “mal”?
Cat
Cat
Mammal
halo-uri:isA
halo-uri:isA
?
Anima
l

17. Query TO and THROUGH rdf:type
• XML: http://halo.vulcan.com:8080/isa/cat/type/animal.xml
• XML: http://halo.vulcan.com:8080/isa/cat/type-graph/animal.xml
<item>
<id>9c5eebf630d626279fa6acbe1f50c9b9</id>
<term>cat</term>
<domain>animal</domain>
<match>true</match>
<triples>
<s>http://dbpedia.org/resource/Cat</s>
<p>http://halo.vulcan.com/lod/2013/11/isa-vocabulary#isA</p>
<o>http://dbpedia.org/ontology/Animal</o>
<search>
<p>http://www.w3.org/2000/01/rdf-schema#label</p>
<o>animal</o>
</search>
</triples>
</item>

18. Query TO and THROUGH rdf:type
• JSON: http://halo.vulcan.com:8080/isa/cat/type/animal.json
• JSON: http://halo.vulcan.com:8080/isa/cat/type-graph/animal.json
{
"id":"9c5eebf630d626279fa6acbe1f50c9b9",
"term":"cat",
"domain":"animal",
"match":true,
"triples":[{
"s":"http://dbpedia.org/resource/Cat",
"p":"http://halo.vulcan.com/lod/2013/11/isa-vocabulary#isA",
"o":"http://dbpedia.org/ontology/Animal",
"search":{
"p":"http://www.w3.org/2000/01/rdf-schema#label",
"o":"animal"
}
}]
}

19. Query TO and THROUGH rdf:type
• Halo.Vulcan SPARQL : Is a “cat” a “mammal”?
PREFIX halo: <http://halo.vulcan.com/lod/2013/11/isa-vocabulary#>
SELECT DISTINCT ?p ?o ?domainLabel WHERE { GRAPH ?G {
?term halo:isA ?o .
?term ?p ?o .
?term <http://www.w3.org/2000/01/rdf-schema#label>
?termLabel .
?o <http://www.w3.org/2000/01/rdf-schema#label>
?domainLabel .
?o rdf:type halo:rdf-type .
FILTER (regex(str(?termLabel), '^cat$', 'i')) .
FILTER (regex(str(?domainLabel), 'mammal', 'i'))
}} LIMIT 100

20. EXAMPLE: 2
Query TO and THROUGH category

21. Query TO and THROUGH category
• Is a “cat” an “animal”?
Cat
halo-uri:isA
Invasive animal
species
Animals described in
1758
Domesticated
animals

22. Searches are Returned with Triples
"triples":[{
"s":"http://dbpedia.org/resource/Cat",
"p":"http://halo.vulcan.com/lod/2013/11/isa-vocabulary#isA",
"o":"http://dbpedia.org/resource/Category:Invasive_animal_species",
"search":{
"p":"http://www.w3.org/2000/01/rdf-schema#label",
"o":"invasive animal species"
}
},{
"s":"http://dbpedia.org/resource/Cat",
"p":"http://halo.vulcan.com/lod/2013/11/isa-vocabulary#isA",
"o":"http://dbpedia.org/resource/Category:Animals_described_in_1758",
"search":{
"p":"http://www.w3.org/2000/01/rdf-schema#label",
"o":"animals described in 1758"
}
}]

23. Query TO and THROUGH rdf:type
• Halo.Vulcan SPARQL : Is a “cat” an “animal”?
PREFIX halo: <http://halo.vulcan.com/lod/2013/11/isa-vocabulary#>
SELECT DISTINCT ?p ?o ?domainLabel WHERE { GRAPH ?G {
?term halo:isA ?o .
?term ?p ?o .
?term <http://www.w3.org/2000/01/rdf-schema#label>
?termLabel .
?o <http://www.w3.org/2000/01/rdf-schema#label>
?domainLabel .
?o rdf:type halo:wikipedia-category .
FILTER (regex(str(?termLabel), '^cat$', 'i')) .
FILTER (regex(str(?domainLabel), ‟animal', 'i'))
}} LIMIT 100

24. ADDITIONAL SERVICES
More graphs, flexible service points, and
unexpected features…

25. There are 4 graphs in Virtuoso
• http://halo.vulcan.com:8890/conductor/sparql_graph.vspx
• http://halo.vulcan.com:8890/isa/rdf-type
• ~87,069 Triples
• http://halo.vulcan.com:8890/isa/rdf-type-graph
• ~101,823 Triples
• http://halo.vulcan.com:8890/isa/category-type
• ~292,239 Triples
• http://halo.vulcan.com:8890/isa/category-type-graph
• ~560,906 Triples
652,677 NORMALIZED TRIPLES ACROSS
ALL GRAPHS

26. “Find All” Service Points
Why query every instance? Just ask the service for all
relations to a term in a given graph.
• All “is a” matches in rdf-type
• http://halo.vulcan.com:8080/isa/cat/type/.xml
• All “is a” matches in rdf-type graph
• http://halo.vulcan.com:8080/isa/cat/type-graph/.xml
• All “is a” matches in categories
• http://halo.vulcan.com:8080/isa/cat/category/.xml
• All “is a” matches in categories graph
• http://halo.vulcan.com:8080/isa/cat/category-graph/.xml
• All “is a” matches in every graph
• http://halo.vulcan.com:8080/isa/cat/.xml

27. Unanticipated Features
• Absolute matching on domain for “is a” relations
• Add a URL for literal matching and update SPARQL regex
• Spacing and special characters need to be URL encoded
because each call is a „GET‟
• Wikipedia categories are of poor quality
• User defined and often inaccurate
• Very specific: “Animal species described in 1705”
• Cyclical: “Republics -> Countries -> United States -> Republics …
• All paths lead to: Philosophy
• Plural categories make for difficult literal matching and odd “is a”
statements: Is a cat a felines?

28. Example Service URLs
Query rdf-types graph:
• Domain-range Query – http://halo.vulcan.com:8080/isa/cat/type/animal.json
• Term isa * Query – http://halo.vulcan.com:8080/isa/cat/type/.json
Query rdf-types and parents graph:
• Domain-range Query – http://halo.vulcan.com:8080/isa/lizard/type-graph/reptile.json
• Term isa * Query – http://halo.vulcan.com:8080/isa/lizard/type-graph/.json
Query category graph:
• Domain-range Query – http://halo.vulcan.com:8080/isa/cat/category/animal.json
• Term isa * Query – http://halo.vulcan.com:8080/isa/cat/category/.json
Query category and parents graph:
• Domain-range Query – http://halo.vulcan.com:8080/isa/cat/category-graph/animal.json
• Term isa * Query – http://halo.vulcan.com:8080/isa/cat/category-graph/.json
Query all IsA graphs (every associated entity types, categories, and parents):
• Domain-range Query – http://halo.vulcan.com:8080/isa/cat/animal.json
• Term isa * Query – http://halo.vulcan.com:8080/isa/cat/.json