Translation of modelling schema into DAML

From: Goodburn, Daniel (Daniel.Goodburn@dsto.defence.gov.au)
Date: 04/24/01 

Hi,

I've been looking at DAML over the past month trying to translate a
modelling framework we currently use for our models (written in XML) into
DAML. The idea is basically to see whether DAML can capture the concepts we
have in our modelling framework so that in future we may just use DAML which
is a more standard format than our XML format.

Basically we use an extended element-attribute-relationship framework, in
which we treat relationships as first-class entities i.e. a relationship can
have attributes and relationships on it too. Our model contains a meta-model
section which is like a schema that describes the second section of the
model, which contains the model elements. We think that the meta-model is
pretty much like an ontology so we are trying to write it using DAML.
However, I'm stuck with how to capture the idea that relationships can have
attributes. The example I'm working with at the moment is a model describing
my research group. Here is the meta-model section:

  <meta>
    <group>
      <system_type type="attribute" valueType="java.lang.String" arity="1"
/>
      <contains type="relation" direction="forward" target="task" arity="-1"
/>    
      <home_page type="attribute" valueType="java.net.URL" arity="1" />
      <wallpaper type="attribute" valueType="java.lang.String" arity="1" /> 
      <name type="attribute" valueType="java.lang.String" arity="1" />
    </group>
    <task>
      <taskTitle type="attribute" valueType="java.lang.String" arity="1" />
      <number type="attribute" valueType="java.lang.String" arity="1" />
      <acronym type="attribute" valueType="java.lang.String" arity="1" />
      <manager type="relation" direction="backward" target="person"
inverse="manages" arity="1" inverseArity="-1" />
      <activities type="relation" direction="forward" target="activity"
inverse="activity_task" arity="-1" inverseArity="-1"/>
      <sponsor type="attribute" valueType="java.lang.String" arity="1" />
    </task>
    <activity>
      <title type="attribute" valueType="java.lang.String" arity="1" />
      <leader type="relation" direction="forward" target="person"
inverse="leads" arity="1" inverseArity="-1" />
      <participant type="relation" direction="forward" target="person"
inverse="participates_in" arity="-1" inverseArity="-1" />
      <contributes_to type="relation" direction="forward" target="activity"
inverse="benefits_from" arity="-1" inverseArity="-1" >
        <contribution type="attribute" valueType="java.lang.String"
arity="1" />
      </contributes_to>
      <benefits_from type="relation" />
      <activity_task type="relation" />
    </activity>
    <person>
      <surname type="attribute" valueType="java.lang.String" arity="1" />
      <firstname type="attribute" valueType="java.lang.String" arity="1" />
      <DSCS_level type="attribute" valueType="java.lang.String" arity="1" />
      <supervisee type="relation" direction="forward" target="person"
arity="-1" inverse="supervisor" inverseArity="1"/>
      <supervisor type="relation" />
      <participates_in type="relation" />
      <manages type="relation" />
      <leads type="relation" />
    </person>
  </meta>

I've tried translating this into DAML by naively mapping element to Class,
attributes to DatatypeProperty, and relation to ObjectProperty, but got
stuck in the case for the Activity class/element which has a relation
"contributes_to" which has an attribute "contribution". Can you put a
DatatypeProperty on a ObjectProperty? Can a DAML property have a property?

To see if I could avoid this I decided that maybe I could describe my
modelling framework using DAML (I thought I could write a meta-meta-model in
DAML describing my meta-model!). But I'm having trouble getting my head
around this. I think DAML should be able to handle this but I'm afraid my
experience with it is too limited at this stage.

I was wondering if anyone with more XML/DAML experience than me might be
able to make some suggestions or at least provide some moral support :-).

Regards,

Daniel

--
Dr Daniel Goodburn	
Enterprise Visualisation Instrumentation and Synchronisation Group
DSTO, ITD L205-2.C.62		
PO Box 1500			    		
Salisbury SA 5108
Australia 		

Phone: +61 8 8259 5505
Fax: +61 8 8259 5589
Email:Daniel.Goodburn@dsto.defence.gov.au 

Only with winter-patience can we bring 
The deep-desired, long-awaited spring.
                              - Anne Morrow Lindbergh

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