D. Kehagias, I. Papadimitriou, D. Tzovaras (CERTH/ITI) J. Hois, J. Bateman (University of Bremen) A...
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Transcript of D. Kehagias, I. Papadimitriou, D. Tzovaras (CERTH/ITI) J. Hois, J. Bateman (University of Bremen) A...
D. Kehagias, I. Papadimitriou, D. Tzovaras (CERTH/ITI)J. Hois, J. Bateman (University of Bremen)
A Methodological Approach for A Methodological Approach for Ontology Evaluation and RefinementOntology Evaluation and Refinement
2nd ASK-IT International Conference2nd ASK-IT International Conference
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Important aspects have been considered on restructuring
Hierarchy/Taxonomy Property Structure Similar Concepts Subtraction of Modules Documentation/Visualization Ranges for Object Properties Disjointness Restrictions Naming Conventions
ASK-IT Ontologies Revision ASK-IT Ontologies Revision
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Hierarchy/TaxonomyHierarchy/Taxonomy
Flat concept hierarchy More tree-like structure
110 concepts on the same level 67 concepts on the same level
Unexploited grouping possibilities for concepts of similar kind
Better grouping of concepts, more clear re-organized structure
Level of abstraction not always taken into account
Same hierarchy-level for concepts of same abstraction-level
Existence of branches differently structured (depth, breadth, etc.)
More balanced (equally developed) hierarchy
Before After
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
ExamplesExamples
Bar
Cafe
Restaurant
Bar
Cafe
Restaurant
FoodAndDrink
Climate
MeanTemperature
Temperature
Weather
MeanTemperature
Temperature
Climate
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Property StructureProperty Structure
No property structure A restructuring has been realized
290 properties not hierarchically grouped at all
Datatype properties on the same top level have been reduced from 198 to 86
Unexploited grouping possibilities for equal domain properties
Better grouping of equal domain properties, more concrete structure
Further information might be interesting New properties have been added for better description
Before After
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
ExamplesExamples
dayValue
nightValue
minValue
maxValue
MeanTemperature
Domain:
Temperature
Domain:
generalInfoOfClimate
generalInfoOfWeather
generalInfoOfMeanTemperature
generalInfoOfTemperature
dayValuenightValue
minValuemaxValue
cloudy
rainy
snowy
sunny
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Similar ontological concepts are repeated frequently
Impairments could be defined only once and their use be extended within other definitions
Re-use mechanism not applicable in OWL-DL
Future implementation in other languages, such as CASL
For example, different kinds of impaired categories (visual, hearing, wheelchair, etc.)
Unexploited possibility for combination to one module and re-using whenever necessary
Before After
Similar ConceptsSimilar Concepts
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Duplicate definitions of the same concept Elimination of one definition
Existence of very similar (or almost identical) concepts
Concepts removed or merged to a single concept
Properties not used at all Properties removed
Complex ontology Reduced complexity, ontology more “clear”, compact and readable
Before After
Subtraction of ModulesSubtraction of Modules
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
POIS_How_to_get_there2
POIS_How_to_get_to_the_pois
POISHowToGetThere
POIHowToGetThere
General_info2
GeneralInfoForALLGeneralInfo
hasAccommodation
hasAccommodationInfohasAccommodation
mean_tmp mean_tmp
ExamplesExamples
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Documentation/VisualizationDocumentation/Visualization
Poor documentation Documentation improved
Almost no comments in the ontology Comments added for most concepts (mainly higher-level ones)
Ontology difficult to use and understand Ontology easier to be applied / re-used in other applications
Examples:
Accommodation :
Climate :
A concept that models a place where someone can stay, e.g. a hotel room.
A concept that models some of the climate characteristics.
Before After
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Ranges for Object PropertiesRanges for Object Properties
No range definition for some object properties Range defined for all object properties
Inconsistencies may appear Avoid inconsistencies
Before After
Examples:
hasMonth
hasWalk
Range:
Range:
Month
Walk
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Disjointness RestrictionsDisjointness Restrictions
Missing disjointness conditions for some concepts
Disjointness restrictions have been reconsidered more carefully
Disjointness might not hold for some other concepts
Disjointness removed from where we might have an overlap
Before After
Examples:
Doctor
Hospital
MedicalService
DisjointSpectatorStandForHearingImp
SpectatorStand
Not disjointSpectatorStand
ForUpperLimbImp
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
Naming ConventionsNaming Conventions
Before After
No alignment for all concept names Alignment for reasons of clearness
For example, they end with “-Impaired”, “-Imp”, or nothing All impairment categories end with “-Imp”
Camel case and underscores mixed Camel case is always used
Plural and singular forms mixed Singular form is adopted
Property names sometimes begin with upper case or lower case letter
All property names begin with lower case letter
Examples:
Local_support_groups LocalSupportGroup
LongBench longBench
22ndnd ASK-IT International Conference, 26-27 June 2008, Nuremberg ASK-IT International Conference, 26-27 June 2008, Nuremberg
More InfoMore Info
http://askit.iti.gr/ontologyhttp://askit.iti.gr/ontology
• ASK-IT Ontology
http://www.ask-it.org/http://www.ask-it.org/
• ASK-IT Web Site