FRE 2672 Urban Ontologies : the Towntology prototype towards case studies Chantal BERDIER (EDU), Catherine ROUSSEY (LIRIS)

2 Ontology Definitions Gruber 1993: « the specification of conceptualisations, used to help programs and humans share knowledge. » Studer 1998 : « Ontology is a formal and explicite specification of a share conceptualisation. »  The conceptualization is an abstract, simplified view of the world that has to be represented for some purpose.  The specification is the representation of this conceptualization in a concrete form. The goal is to create an agreed-upon vocabulary and semantic structure for exchanging information about that domain.

3 Ontology Objectives Expert System  Knowledge based System Knowledge separation from treatment in order to solve a specific problem or to achieve a task. Knowledge reuse in different systems Problem Solving Method Method inputMethod output Method ontology Application ontology Domain ontology Described by mapping Extended to

4 4 Ontology Classifications Classification according to : 1.Formalization, 2.Expressiveness, 3.Purpose, 4.Specificity

5 Classification according to Formalization Depend on the language used to describe the ontology highly informal:  Yahoo directory semi-informal:  French Architecture Thesaurus semi-formal:  Dublin Core metadata Initiative in RDF. rigorously formal:  measurement ontology in KIF.

6 Classification according to Expressiveness  Terms  Natural Language Definition  Concepts, class, type  Relation type, property type  Concept taxonomy  Relation type taxonomy  Properties and Attributes  Constraints  Formal definition  Axiom, facts  Rules Lightweight Ontology Heavyweight Ontology

7 Classification according to Purpose Application ontology  Ontolingua,  Protégé Reference ontology  PSL standard

8 Classification according to Specificity Generic Ontology  Generic concept applicable on many fields  Example: measure concept Core Ontology  Core concept of urban domain applicable to urban field  Example: network concept Domain Ontology  Specific Concepts of a field.  Example: electricity network.

9 Towntology Project Formalization:  Semi informal / formal ontology Expressiveness  Lightweight Ontology Purpose  Reference ontology Specificity  Domain ontology

10 Towntology Browser Semantic network List of terms

11 Image Browser List of concepts Interactive zones

12 Towntology Browser: Information Frame relationsdefinitionsImagereferences

13 Road System Ontology roadway Track Bridge Giratory Structure Draining road Pavement Cycle strip Cycle path Urban trip Building outline Road way structure Hierarchical Road Road Auscultation Black Undulation Sevader has tool is a is used for is a computing tool for has problem has activity about characterize is located on is composed of has tool

14 Road System Visualisation in Context

15 7 classes of relationship types Relation of localization  « is located on »  « is located in » Relation of use :  « is used for »  « is used by »  « can hold the role » Relation of composition : « is composed of » Relation of subordination :  « depends on »  « works for » Relation of being : « is a(n) » Relation of characterization  « is characterized by »  « says itself for » Relation of generation: « is resulting from »

16 Urban Mobility Ontology Mode of transportation Captive User of road Pedestrian Car walking cycling Bus Mean of public transport Noise Nuisance Pollution Externality Disabled person Motorized mode of transportation Mode of transportation not motorized TramwaySubway

17 Urban Renewal Ontology Urban renewaldemolition High rise estate Is located on reconstruction Is composed of Is followed by operation Is a Social problem unemployement Is resulting from educational failure Is characterized by Family of numerous childs Functionalism theory form Construction period Industrial techniques of building Is linked

18 Towntology report To add the attributes and measurements To develop a base of knowledge  Description of a particular situation  Example: the rehabilitation of the Lacassagne street in Lyon. Limit of the tool :  All the concepts are represented in the same way  No visible hierarchy of concepts (identification of the level of specialization, or degree of association of the concept)  no filter on the domain/level, etc…  no regrouping of similar concepts in various fields (example : operation)  No global vision of the complexity of certain urban fields (example : urban renewal)  Sometimes a simplistic modelling of the field.

19 Guidelines To make a good choise of Domain : technical domain is easier  Consensus and mathematical rigour Documentation (dictionary, books, standards) To think about the meaning of relations upstream  Hierarchical relation To think about general concepts and core concepts  « general concepts » enable to build a good hierarchy  To define the difference between « brother concepts ». To limit the number of relations

20 Conclusion All the fields of urban are not necessarily formalisable. A minimum of stability in the definitions is required. Urban is able to generate any kind of ontology: formal, informal etc...  For example : technical fields of urban like roadway system can give rise to a formal ontology  Urban renewall for example give rise to abstract ontology.It Is a constructing domain. One should not seek to make consensus but to create footbridges between various levels of vocabularies...