The document discusses using ontologies to build applications. It introduces ontology representation and manipulation using OML (Ontology Manipulation Language). OML allows defining rules to query and modify ontologies through patterns and actions. The approach embeds OML programs directly into Perl to take advantage of Perl modules while gaining ontology awareness. Examples demonstrate an ontology-driven map application built with this technique.

1. Ontology Aware Applications
Portuguese Perl Workshop 2011
Nuno Carvalho <smash@cpan.org>
Nuno Carvalho <smash@cpan.org> PtPW2011: Ontology Aware Applications 1

2. Introduction
ontologies can he used to store data
create, query, manipulate, maintain, reason, ...
build applications using ontologies to store information
approaches for representing ontologies
mechanisms to implement common operations
want to use all this with our favourite programming language
to develop applications
Perl × ontology −→ modern rich ontology aware applications
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3. Introduction
Motivations
ontology use is growing
solutions based in this technology are growing
Semantic Web, etc.
ontologies are a good approach to store knowledge
ontologies are easy to share, store, replicate, ...
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4. Background
Ontology
A domain ontology is an engineered artifact that informally defines
concepts from a specific domain, representing and organizing them
as conceptualizations which a set of systems working cooperatively
with each other agree to share.
city
-7.84 ..
Vila Real
DST
LAT
ISA LNG
ISA 39.63 ..
IN
Chaves
LAT Lisbon
Portugal
-7.47 .. LNG IN
ISA
41.74 .. country
terms relations
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5. Ontology Representation
Biblio::Thesaurus + ISO 2778
simple and uses a simple representation
not only thesaurus
easy to push features
is written in Perl
Braga
CITY-OF Portugal
IS-A city
Vigo
CITY-OF Spain
IS-A city
Nuno Carvalho <smash@cpan.org> PtPW2011: Ontology Aware Applications 5

6. Ontology Manipulation
OML Programs
describe operations on ontologies
list of rules
each rule has a:
a pattern to look for
an action list to execute
produce side effects
expressive, powerful, yet simple
embedded programs
Rules
pattern => actions.
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7. OML Syntax Overview
OML Program
program → rule +
rule → Pattern => Action .
Pattern
a pattern of information, terms and relations, that can be
found once or more than once in the ontology
Action
manipulate information in the ontology
add, remove, terms or relations, ...
produce any arbitrary user defined side effects
produce graphs, images, HTML pages, update databases, ...
Nuno Carvalho <smash@cpan.org> PtPW2011: Ontology Aware Applications 7

8. Ontology Example
city
-7.84 ..
Vila Real
DST
LAT
ISA LNG
ISA 39.63 ..
IN
Chaves
LAT Lisbon
Portugal
-7.47 .. LNG IN
ISA
41.74 .. country
terms relations
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9. OML Patterns Examples
# Pattern
1 term(Chaves) term Chaves exists
2 rel(ISA) relation ISA exists
3 term($t) for all terms
4 rel($r) for all relations
5 Chaves ISA city
6 $name ISA city
7 $name ISA $place
8 Chaves $rel $term for all related to Chaves
9 Chaves ISA city ∧ Portugal ISA country
10 Chaves ISA city ∨ Portugal ISA country
11 Chaves LAT $lat ∧ Chaves LNG $lng
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10. OML Actions Examples
Manipulate Information
add(Portugal ISA country)
del($place ISA city)
Arbitrary Effect
sub {
$db->execute(
’INSERT INTO cities (name) VALUES ($city)’
);
}
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11. OML Rules Examples
$city IN Portugal ⇒ add($city IN Europe).
$c ISA city ∧ $c IN Portugal ⇒ add($c LANG Portuguese).
$city ISA city ∧ $city ISA country ⇒
sub { print ”Warning: review $city ISA relation!” }.
;
$name ISA city ∧ $name IN $country ⇒ sub {
$db->execute(
’INSERT INTO cities (name,country) VALUES ($name,$country)’
)}.
$a $r $b ∧ $b $r $c ⇒ add($a $r $c).
$a $r $b ∧ $b $r $c ∧ $a $r $c ⇒ rem($a $r $c).
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12. OML Compiler
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13. Architecture Overview
ontology
program compiler result
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14. Compiler Architecture Overview
program parser
ontology pTree
expander
diTree
reactor result
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15. Embedded OML
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16. Embedded OML
Challenge
can applications and tools be written only in OML?
actually yes, but do we want to?
NO!
Why?
efficient for ontology processing
real world applications require more
HTML operations, databases, ...
we want the best of both worlds
OML for ontology aware tasks
general purpose programming language for everything else
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17. Embed OML
Initial
Program
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Perl
Perl Perl
Perl
Perl Perl
Perl
+ Perl Result
OML Perl
Perl Perl
Perl
OML Perl
compile
Final
Result
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18. Embedded OML Algorithm
Algorithm 1: Weaver(program,split,compile,combine) : program
Input: program – original program to process
Input: split – function that separates the code parts by language
Input: compile – tranforms OML into Perl
Input: combine – joins parts of code together
parts ← split(program)
forall the (lang , code) ∈ parts do
if lang is DSL then
code ← compile(code)
push(parts2, code)
returncombine(parts2)
Nuno Carvalho <smash@cpan.org> PtPW2011: Ontology Aware Applications 18

19. Embed OML in Perl
Why Perl?
provides modules for ”everything else”
easy to extend
Example:
1 use Biblio : : Thesaurus : : ModRewrite : : Embed ;
2
3 my $term = $ARGV [ 0 ] ;
4 my $ontology = thesaurusLoad ( $ARGV [ 1 ] ) ;
5
6 OML printTerms ( ontology , term )
7 term $r $t = sub { print ”term $ r $ t n ” ; } .
>
8 $t $r term = sub { print ”$ t $ r term n ” ; } .
>
9 ENDOML
10
11 printTerms ( $ontology , $term ) ;
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20. Example: OntoMap
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21. Example Screenshot
Nuno Carvalho <smash@cpan.org> PtPW2011: Ontology Aware Applications 21

22. Information in JSON
GET /locations.cgi HTTP/1.1
(...)
Content-Type: application/json; charset=UTF-8
{"markers":[{"name":"Braga","desc":"Braga<hr><b>CITY-OF</b>
Portugal<br><b>IS-A</b> city<br><b>LAT</b> 41.5517605<br><b
>LNG</b> -8.4229034<br>","lat":"41.5517605","lng":"-8.42290
34","is":"city"},{"name":"Castelo de Alva","desc":"Castelo
de Alva<hr><b>IS-A</b> castle<br><b>LAT</b> 41.0913745<br><
b>LNG</b> -6.8078773<br>","lat":"41.0913745","lng":"-6.8078
773","is":"castle"},{"name":"Castelo de Tavira","desc":"Cas
telo de Tavira<hr><b>IS-A</b> castle<br><b>LAT</b> 37.12131
22<br><b>LNG</b> -7.6533538<br>","lat":"37.1213122","lng":"
-7.6533538","is":"castle"},{"name":"Guimaraes","desc":"Guim
araes<hr><b>CITY-OF</b> Portugal<br><b>IS-A</b> city<br><b>
LAT</b> 41.4419546<br><b>LNG</b> -8.2956069<br>","lat":"41.
4419546","lng":"-8.2956069","is":"city"},{"name":"Lagos","d
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23. OML Program: locations.cgi
1 use CGI ;
2 use JSON ;
3 use Biblio : : Thesaurus : : ModRewrite : : Embed ;
4
5 my $onto = thesaurusLoad ( ’ geo . iso ’ ) ;
6 my $filter = param ( ’ FILTER ’ ) or ’ ANY ’ ;
7 print header ,
8 ”{ m a r k e r s : ” ,
9 get points ( $onto , $filter ) ,
10 ”} ” ;
11
12 OML get points ( ontology , filter )
13 $point LAT $x AND $point LNG $y
14 AND $point ISA filter
15 = sub {
>
16 print to json ( {name= >$point , lat=>$x , lng=>$y} ) ;
17 }.
18 ENDOML
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24. OML Program: addlocation.cgi
1 use CGI ;
2 use Biblio : : Thesaurus : : ModRewrite : : Embed ;
3
4 my $name = param ( ’ NAME ’ ) ;
5 my $isa = param ( ’ ISA ’ ) ;
6 my $lat = param ( ’ LAT ’ ) ;
7 my $lng = param ( ’ LNG ’ ) ;
8
9 my $onto = thesaurusLoad ( ’ geo . iso ’ ) ;
10 add location ( $onto , $name , $isa , $lat , $lng ) ;
11 $onto−>save ( ’ geo . iso ’ ) ;
12
13 OML add location ( ontology , name , isa , lat , lng )
14 do =>
15 add ( name ISA isa )
16 add ( name LAT lat )
17 add ( name LNG lng ) .
18 ENDOML
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25. Conclusion
language easy to use, efficient
easy to compose with other tools
elegant and simple approach to build ontology-aware
applications
modular, build complex applications using small blocks
embedded mechanism is a clear advantage
weaving mechanism can be extended for other languages
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26. Conclusion
weaving mechanism can be language-agnostic
split many languages
having compilers for each language
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Perl
Perl Perl
Perl
Perl Perl
Perl
+ Perl Result
DSL* Perl
Perl Perl
Perl
DSL Perl
compile*
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27. Conclusion
this mechanism can be adopted in any GPL
dynamic language
allows pre-processing of source code
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Perl
Perl Perl
Perl
GPL GPL
GPL
+ GPL Result
DSL* Perl
Perl Perl
Perl
DSL GPL
compile*
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28. Thank You!
Nuno Carvalho <smash@cpan.org> PtPW2011: Ontology Aware Applications 28