Saturday, March 25, 2006

The major ideas of the Semantic Links area

There are three main points in the Semantic Links area: 1. Web Ontology Language (OWL) is used to represent structure of resources; 2. The resources should be easily readable and accessible for users; 3. The resources should be understandable by services. So I use OWL to represent data. You can see the example here but please don’t subtilize ;) Such data is really understandable by the software agents or services but not for people. For people it’s more appropriate to have something like picture 1 to understand the hierarchy on nouns:
And something like picture 2 to understand the structure of resources and to manage resources:

These screenshots show how the Protégé represents OWL classes and instances. To represent the instance Protégé uses widgets conception. For every slot in OWL class it will define default user interface widget of corresponded type. User can change the default widget for something else. E.g. if you have some text slot, it can contain the URI of image. So the user can use an image widget to view image by URI. The Semantic Links area utilizes the same idea. So I have a main OWL model that contains the meaning information (catalog.owl) and the model of UI representation (uidata.owl). The model of UI representation contains definitions of UI elements. So I used OWL to represent the meaning data and UI definitions. The UI definitions determine the representation of resources. The following OWL example expresses such approach:

<Widget rdf:ID="uiformdescriptions_RDFResource_38"> <Name rdf:datatype="">http://reflections/bcatalog#Service</Name> … <Widget rdf:ID="uiformdescriptions_RDFResource_22"> <Left rdf:datatype="" >20</Left> <Name rdf:datatype="" >http://reflections/bcatalog#ImageURI</Name> <Top rdf:datatype="">80</Top> <WidgetRealizationName rdf:datatype="" >IconWidget</WidgetRealizationName> <Caption rdf:datatype="" >Image</Caption> <Width rdf:datatype="" >300</Width> <Properties rdf:resource="#uiformdescriptions_RDFResource_15"/> <Height rdf:datatype="" >60</Height> </Widget> … </Widget>

This example shows that widget for http://reflections/bcatalog#Service class contains widget that represents http://reflections/bcatalog#ImageURI slot. To represent slot IconWidget will be used. In the following picture the UI of http://reflections/bcatalog#Service depicted.

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