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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