Ontology Aware Applications

Ontology Aware Applications

Portuguese Perl Workshop 2011

Nuno Carvalho <smash@cpan.org>

Nuno Carvalho <smash@cpan.org> PtPW2011: Ontology Aware Applications 1

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


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, ...


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


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


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.


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, ...


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


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


OML Actions Examples

Manipulate Information
add(Portugal ISA country)
del($place ISA city)

Arbitrary Eﬀect
sub {
$db->execute(
’INSERT INTO cities (name) VALUES ($city)’
);
}


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).

OML Compiler


Architecture Overview

ontology

program compiler result


Compiler Architecture Overview

program parser

ontology pTree

expander

diTree

reactor result


Embedded OML


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


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


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)


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 ) ;


Example: OntoMap


Example Screenshot


Information in JSON

GET /locations.cgi HTTP/1.1
(...)
Content-Type: application/json; charset=UTF-8

{"markers":[{"name":"Braga","desc":"Braga<hr>CITY-OF
Portugal IS-A city LAT 41.5517605 LNG -8.4229034 ","lat":"41.5517605","lng":"-8.42290
34","is":"city"},{"name":"Castelo de Alva","desc":"Castelo
de Alva<hr>IS-A castle LAT 41.0913745 LNG -6.8078773 ","lat":"41.0913745","lng":"-6.8078
773","is":"castle"},{"name":"Castelo de Tavira","desc":"Cas
telo de Tavira<hr>IS-A castle LAT 37.12131
22 LNG -7.6533538 ","lat":"37.1213122","lng":"
-7.6533538","is":"castle"},{"name":"Guimaraes","desc":"Guim
araes<hr>CITY-OF Portugal IS-A city 
LAT 41.4419546 LNG -8.2956069 ","lat":"41.
4419546","lng":"-8.2956069","is":"city"},{"name":"Lagos","d

OML Program: locations.cgi

1 use CGI ;
2 use JSON ;
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


OML Program: addlocation.cgi

1 use CGI ;
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


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


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*


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*


Thank You!


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