A Bottom-Up Approach for Licences Classification and Selection

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Enrico Daga (KMi-OU)Mathieu d’Aquin (KMi-OU)Aldo Gangemi (CNR & Universite’ Paris13) Enrico Motta (KMi-OU)

June  1st,  2015    Interna0onal  Workshop  on  Legal  Domain  And  Seman0c  Web  Applica0ons    ESWC  2015  Workshop  hCp://cs.unibo.it/ledaswan2015

Background

• Licences are important in the web of (linked) data• We can describe licences/policies (RDF+ODRL)• Exploiting these descriptions for license selection

is hard due to the high number of different features

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Question

How can we reduce the effort for licence identification and selection?

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Hypothesis

An ontology defining relevant classes of licences, formed on the basis of the key features of the instances, should facilitate the selection and identification of a suitable licence.

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Methodology

A bottom-up approach to ontology construction • RDF License Database• Ontology production with Contento• Based on Formal Concept Analysis• User can annotate and prune concepts• Produces an OWL Ontology

• License Picker Ontology (LiPiO)• Evaluation: License Picker Webapp

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Formal Concept Analysis (FCA)

• A data analysis method• Studies how objects can be hierarchically grouped together

according to their common attributes• Input is a Formal Context

– a binary matrix of objects/attributes• Basic unit is a Concept:

– (O,A) => (Extension,Intension)– Operator ’ … (O,A) is a concept when O’=A and A’=O

• Classifies concepts hierarchically in a concept lattice– Top: all objects, no attr, bottom: all attributes, no obj

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Contentohttp://bit.ly/contento-tool

Support the user in the generation and curation of concept lattices from formal contexts and use them as semantic web ontologies.

Formal  Context

Concept  LaNce

Modeling  (Naming  &  Pruning)

Export  as  OWL  

Ontology

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Contentohttp://bit.ly/contento-tool

Support the user in the generation and curation of concept lattices from formal contexts and use them as semantic web ontologies.

Formal  Context

Concept  LaNce

Modeling  (Naming  &  Pruning)

RDF  Licence  Database

Licence  Picker  

Ontology

Export  as  OWL  

Ontology

Fo Co MR LicEx

RDF License Databasehttp://datahub.io/dataset/rdflicense *

~140 licences expressed in RDF/ODRL

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<hCp://purl.org/NET/rdflicense/cc-­‐by-­‐nc4.0>              a              odrl:Policy  ;              rdfs:label  "Crea0ve  Commons  CC-­‐BY-­‐NC"  ;              rdfs:seeAlso  <hCp://crea0vecommons.org/licenses/by-­‐nc/4.0/legalcode>  ;              cc:legalcode  <hCp://crea0vecommons.org/licenses/by-­‐nc/4.0/>  ;              dct:alterna0ve  "CC  BY-­‐NC"  ;              dct:hasVersion  "4.0"  ;              dct:language  <hCp://www.lexvo.org/page/iso639-­‐3/eng>  ;              dct:publisher  "Crea0ve  Commons"  ;              dct:0tle  "Crea0ve  Commons  -­‐  ACribu0on-­‐NonCommercial  4.0  Interna0onal  -­‐  CC  BY-­‐NC  4.0"@en  ;              odrl:permission                  [  odrl:ac0on  cc:Distribu8on  ,  ldr:extrac8on  ,  ldr:reu8liza8on  ,  cc:Deriva8veWorks  ,  cc:Reproduc8on  ;              odrl:duty    [  odrl:ac0on  cc:ABribu8on  ,  cc:No8ce]  ]  ;              odrl:prohibi8on                              [  odrl:ac0on  cc:CommercialUse  ]  ;              foaf:logo  <hCp://i.crea0vecommons.org/l/by-­‐nc/2.0/88x31.png>  .

Fo Co MR LicEx

(*) Victor Rodrıguez-Doncel, Serena Villata, and Asuncion Gomez-P ́erez. A dataset of RDF licenses. In Rinke Hoekstra, editor, Legal Knowledge and Information Systems. JURIX 2014: The Twenty-Seventh Annual Conference. IOS Press, 2014.

Formal ContextObjects: Apache 2.0, CC-A-SA 3.0, …Attributes: duty attribution, permission Copy, prohibition derive, …

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RDF    Licence  Database

Licence,Policy,Bool  Apache,Duty  No0ce,True  

…  (as  CSV)

Fo Co MR LicEx

Concept Lattice• Applying FCA, a concept lattice is produced• The top concept representing All the licences, while the bottom

concept, None, includes all the attributes, and no licence. • However, this lattice need to be interpreted…

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Modeling: Naming & Pruning

• Inspect each concept• If it is meaningful annotate it

– eg: “should others be allowed to distribute the work?”

• … otherwise delete it– and the hierarchy is adjusted

accordingly– objects are present in direct

upper concepts, attributes in direct lower

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• Approach: a concept is meaningful if it’s intent introduces new features (policies)

• If not:– it is a union of the intents of the

respective upper concepts,– the respective licences will be

present in (at least one of) the upper concepts,

– no new question need to be asked to identify them.

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Modeling: Naming & Pruning

Fo Co MR LicEx

Modeling: Naming & Pruning

• With this process the lattice has been reduced significantly.• Almost 20% of the initial lattice • Labels being synthetic names referring to policies/attributes that have

been introduced in that point of the hierarchy • Each concept has a Question

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Export as OWL Ontology

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rdfs:subClassOfrdf:type

ex:has-­‐aBribute  .  .  .

give semantics!

Fo Co MR LicEx

contento_ns:7582 rdf:type contento:Concept ;

rdfs:label "Copyleft" ;

rdfs:comment "Should the licence require to share any derived or combined content under the same terms?" ;

rdfs:subClassOf contento_ns:7856 ,

contento_ns:7678 ,

contento_ns:7956 .

contento_ns:7586 rdf:type contento:Concept ;

rdfs:label "Read" ;

rdfs:comment "Should the licence permit to read (access) the data?" ;

rdfs:subClassOf contento_ns:7648 .

contento_ns:7632 rdf:type contento:Concept ;

rdfs:label "ND" ;

rdfs:comment "Should the licence prohibit derivative works?" ;

The Licence Picker Ontologyhttp://bit.ly/licence-picker-ontology

Can be exploited as a decision tree!

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Focus is on Key Questions

Fo Co MR LicEx

Evaluation The Licence Picker Webapphttp://bit.ly/licence-picker-webapp

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The user is engaged in answering questions regarding her requirementsBy applying the Licence Picker Ontology (LiPiO), this task is reduced to answering an average of 3/5 questions and assessing the best licence from a small set of choices.

Conclusions and Future Work• A bottom-up approach on ontology building in this scenario opens

new interesting challenges • The RDF description of licences is an ongoing work • Data has been curated in advance (harmonised)• Data has impact on the whole process!

– explore methods to automate some of the curation tasks (especially pruning)

– to integrate changes in the formal context incrementally – to support the ontology designer in the adaptation of the ontology

• New features: type of asset, jurisdiction …• Contento: a generic tool, need user-based evaluation

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Thank you

Enrico Dagaenrico.daga@open.ac.uk