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Re: Need help developing Camera model

From: Roger L. Costello <costello@mitre.org>
Date: Mon, 14 Apr 2003 11:55:34 -0400
Message-ID: <3E9AD9F6.A16689FD@mitre.org>
To: www-rdf-interest@w3.org
CC: "Costello,Roger L." <costello@mitre.org>

Hi Folks,

Thanks a lot for all your suggestions on modeling camera data!  I
haven't yet had the chance to digest all your suggestions.  I will do
that tomorrow.

In the meantime, I have a question:

Suppose the I were to model the Camera class like this:

Camera = unionOf(Body, Lens)

Read this as: "The Camera class is the union of the Body class and the
Lens class."

Suppose that Body has this property: shutter-speed.
Suppose that Lens has these properties: compatibleWith, f-stop, and
focal-length.

Question: does Camera inherit all the properties from Body and Lens?  

If so, then I see that the above way of modeling the Camera data has a
major flaw: it allows compatibleWith to be a property of Camera, i.e., 

<Camera rdf:ID="Olympus-OM-10">
   <compatibleWith rdf:resource="..."/>
   <shutter-speed>1/2000 - 10 sec.</shutter-speed>
   <f-stop>4.0-4.5</f-stop>
   <focal-length>75-300mm zoom</focal-length>
</Camera>

I can probably accept shutter-speed, f-stop, and focal-length as
properties of Camera.  But compatibleWith is clearly not reasonable.

Okay, I have convinced myself that this is NOT the way to model the
Camera data.  Comments?  

/Roger


"Roger L. Costello" wrote:
> 
> Hi Folks,
> 
> I need some help developing a model for camera data. I've got some of it
> developed, but aspects remain elusive.  Here's what I would like to
> model:
> 
> 1. SLR is a subclass of Camera.
> 2. Large-Format is a subclass of Camera.
> 3. Digital is a subclass of Camera.
> 4. Body has a property shutter-speed, which has a range xsd:string.
> 5. Lens has a property f-stop, which has a range xsd:string.
> 6. Lens has a property focal-length, which has a range xsd:string.
> 7. Body and Lens have a property cost, which has a range xsd:decimal.
> 8. Camera, SLR, Large-Format, and Digital all have the properties
>    shutter-speed, f-stop, and focal-length.
> 9. Consider this:
> 
>     <Body rdf:about="http://www.olympus.com#Olympus-OM-10-body">
>          <shutter-speed>1/2000 sec. to 10 sec.</shutter-speed>
>          <cost>$345 USD</cost>
>     </Body>
> 
> I want to be able to infer that this is data about a Camera Body.  That
> is, if my Web Bot is searching for Camera info, it should be able to
> infer that this is in fact Camera info.
> 
> 10. Consider this:
> 
>     <Lens rdf:about="http://www.olympus.com#EX38">
>          <compatibleWith
>             rdf:resource="http://www.olympus.com#Olympus-OM-10-body
>          <focal-length>75-300mm zoom</focal-length>
>          <f-stop>4.0-4.5</f-stop>
>          <cost>$295 USD</cost>
>     </Lens>
> 
> I want to be able to infer that this is data about a Camera Lens.  That
> is, if my Web Bot is searching for Camera info, it should be able to
> infer that this is in fact Camera info.
> 
> Those are the things that I want to model.  The relationship between
> Body and Camera, and Lens and Camera are especially fuzzy in my mind.
> Can you help flesh out this model?  /Roger
Received on Monday, 14 April 2003 11:57:24 GMT

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