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Re: purpose/goals for observations ontologies

From: Krzysztof Janowicz <janowicz@uni-muenster.de>
Date: Wed, 05 Aug 2009 00:12:11 +0200
Message-ID: <4A78B23B.3030203@uni-muenster.de>
To: "Kevin R. Page" <krp@ecs.soton.ac.uk>
CC: public-xg-ssn@w3.org
Hi Kevin,

thanks for your mail, I agree with most of your arguments.

Krzysztof

Kevin R. Page schrieb:
> Hello John, comments inline,
>
> On Tue, 2009-08-04 at 13:52 -0600, John Graybeal wrote:
>   
>> On Aug 4, 2009, at 10:20 AM, Kevin R. Page wrote:
>>
>>     
>>> We should recognise that both user-oriented (data) and process- 
>>> oriented
>>> (sensor) use cases exist (as reflected in current OGC standards).
>>>       
>> I am having trouble with this framing; maybe just an ambiguity, or  
>> maybe more.
>>     
>
> So I know there are those on this list who are more familiar, and can no
> doubt elaborate more eloquently, on the distinctions made in current OGC
> standards - please do (and correct me :)  )
>
> I guess my bracketed 'data' and 'sensor' above show where I see the
> differences (and I don't want to overdo them as differences).
>
> I'll start with an (over-simplistic) description of where I'm coming
> from:
>
> 1) sometimes, we might start with a sensor network, with it's elements
> described according to the device ontology. We might use the ontology to
> manage the sensor network. We might use the descriptions of sensor
> properties and data capabilities to pick out particular sensors, and
> from there get to the data that sensor has produced. Absolutely, this is
> the device ontology.
>
> 2) at other times we might start with a large amount of data produced by
> a sensor network, and from that we want to create useful information.
> It's more than just data; we care about concepts like observations,
> measurements, context, so that we can process the data effectively.
> Descriptions about the actual sensors is metadata to this data; that's
> not so say it isn't important, it very much is (e.g. as provenance, or
> to infer the classification of the data from the sensor capabilities),
> but we're starting from the data.
>
>
> I don't think there's any horrific difference or schism here. There's
> obviously overlap - it's the same data. Sometimes you come at different
> parts of it from different directions.
>
> And it's much easier to bring these two viewpoints together in the RDF
> world than the XML Schema world.
>
> So a device ontology might have some O&M concepts included; an O&M
> ontology might have some device concepts included; it might be one big
> ontology (don't have to use all of it, after all).
>
> As long as whatever ontology (or ontologies) we end up with enables us
> to just have devices, or just have observations, and get from one to the
> other as and when we can (or want to) link that data.
>
>
> >From another perspective: semantic web technologies can be applied to
> improve sensor networks; but I think it's equally, if not more,
> important that sensor networks and the data they output become part of
> the semantic web of data. These aren't orthogonal tasks.
>
>
>   
>> I agree that use cases about the (actual output) data *produced by*  
>> sensors exist.
>>     
>
> and it matters that this data was produced by sensors; these use cases
> need to capture and encode this.
>
>
>   
>> Use cases about the data *describing* actual sensors  
>> (name, size, color, and all that) also exist. The latter is what I  
>> thought a device ontology should encompass.
>>     
>
> Yes. And perhaps 'device ontology' is a clearer description of that
> ontology if it doesn't include O&M concepts.
>
>
>   
>> So, which of these did you mean by 'user-oriented (data)'?  (I suggest  
>> that 'user-oriented' is entirely a function of the user, and some  
>> users care only about the devices, not their data; so maybe this isn't  
>> an optimal term.)
>>     
>
> Indeed, I am not fond of the term.
>
> So I think 'user-oriented (data)' as originally cited is the former -
> but the data describing sensors is still there as (vital) metadata.
>
> (Illustrative use of the term 'metadata' - I'm not sure I believe in
> metadata enough to classify what is and isn't data ;)  )
>
>
>   
>> Will the introduction of the 'process oriented' way of looking at the  
>> device -- the framing introduced by SensorML, which I have heard  
>> summarized as "the sensor is a process", right? -- tell me more, less,  
>> or the same information as a 'simple descriptive model'?
>>     
>
> About the device? The same. I think the 'process' concept encapsulates
> the manner by which the observation was gathered. When this is a sensor,
> the information about the 'process' instance is (or could be) the simple
> descriptive model / the device ontology.
>
>
>   
>> Put another way, is there necessarily any difference between the two?
>>     
>
> I'd rather there not be. I think we can do both.
>
> As Krzysztof's recently arrived email says, a good starting place is
> probably to extend the observation concept in the sensor ontology.
>
>
>   
>> To tie this back to the larger question I started with, It just seems  
>> to me that where some element comes from a process, the ontology will  
>> naturally describe that ("sensor producesDataRecord recordType1").
>>     
>
> And when I come across an instance of 'recordType1' I want to know that
> it was produced by an instance of 'sensor'.
>
>
>
> Regards,
>
> Kevin
>
>   


-- 
Krzysztof Janowicz
Institut für Geoinformatik
Westfälische Wilhelms-Universität Münster
Weseler Straße 253
D-48151 Münster
fon: 0049 - 251 - 83 39764
fax: 0049 - 251 - 83 39763
janowicz@uni-muenster.de
http://ifgi.uni-muenster.de/~janowicz 

'Die Wahrheit ist das Kind der Zeit, nicht der Autorität' 
(Bertolt Brecht)
Received on Tuesday, 4 August 2009 22:12:47 GMT

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