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Re: ISSUE-2 (All processes are systems): All processes are systems [sensor ontology - http://mmisw.org/orr/#http://www.w3.org/2009/SSN-XG/Ontologies/SensorBasis.owl - 09.12.15 ]

From: John Graybeal <jbgraybeal@mindspring.com>
Date: Wed, 16 Dec 2009 11:34:24 -0800
Cc: Semantic Sensor Network Incubator Group WG <public-xg-ssn@w3.org>
Message-Id: <5FDDDCEF-AB62-48B2-96B0-8E1D6E81E718@mindspring.com>
To: Manfred Hauswirth <manfred.hauswirth@deri.org>
I found these observations to be helpfully concrete, so I'd like to  
add my own (inline).

On Dec 16, 2009, at 09:50, Manfred Hauswirth wrote:

> Hi,
>
> as I may not be able to join today's call (50/50 chance - one of my  
> kids got sick), I am starting the discussion via mail.
>
> Let me start with a disclaimer: I generally think it is a good idea  
> to stay in sync with existing standards. But I think it may be  
> better to deviate if something is problematic. This is especially  
> relevant when it comes to modeling an ontology, which not only  
> should provide a concise classification system but also be a  
> "natural way" (for lack of a better term) of modeling a domain. I  
> the modeling is not "natural", people will not understand it and  
> thus not use it.

+1

> Regarding "all systems are processes": Honestly, I would not  
> understand this (I stated this at the F2F). For me, you have systems  
> which include one ore more processes. If systems are processes, why  
> have systems at all. My notion of systems would informally consist  
> of processes, scenarios, deployments, etc.

The question "why have systems at all?" is the crux here.  Can we  
state clearly when a process is not a system? Or in other words, how  
is a system more narrow than a process?

Incidentally, my notion of processes would informally consist of the  
same list.  I am also having trouble drawing the distinction.

> PhysicalSystem: I don't remember the exact reason for this. Did we  
> mean deployment?

I assume this is to distinguish it from a software system.

> Sensor as subclass of Device: I think this is too narrow. I can  
> think of sensors which are not devices at all, e.g., human "sensors"  
> in the context of social sensing (which is an accepted concept in  
> many domains including CS by now). Making sensors a subclass of  
> device limits us to purely technical systems in hardware, IMHO. Is  
> an RSS feed a device? I can clearly use it as a sensor. I think that  
> Device should be a subclass of Sensor. Even in existing middelware  
> systems like our GSN we followed that path (without having an  
> ontology in mind at all).

This gets to purpose of the ontology.  As I understood it, the group  
was originally constructed to model hardware sensors. (May have just  
been a wrong assumption on my part.  More precisely, what we clearly  
were not doing is modeling samplers, that is, devices that return a  
physical sample.)

So using one definition of sensor ("anything that senses") makes  
Sensor very broad, and other things would subclass to it. (Since some  
devices (a hammer) don't sense things, we'll have to define Device  
narrowly to make it a subclass Sensor.)  Using another definition of  
sensor ("a component that detects (measures) a physical phenomenon,  
converting it into a digital representation that can be output to  
other components"), a Sensor is clearly a specific type of Device, and  
is also a component of any sensing device.

Do we have a set of definitions by any chance, so we can all use these  
(or some) terms the same way?

> Why is a Device a subclass of a Process? A Process can use Sensors  
> which are manifested as Devices to do/measure something, IMHO. Again  
> this is a quite narrow notion of the concepts.

I'm not following your argument here.  Yes, a Process can use Sensors  
as you say. So can a Device.  There is no inconsistency that I can  
see.  This suggests a Device is in fact a type of Process.

> Talk to you later (hopefully),
>
> Manfred
>
> Semantic Sensor Network Incubator Group Issue Tracker wrote:
>> ISSUE-2 (All processes are systems): All processes are systems  
>> [sensor ontology - http://mmisw.org/orr/#http://www.w3.org/2009/SSN-XG/Ontologies/SensorBasis.owl 
>>  - 09.12.15 ]
>> http://www.w3.org/2005/Incubator/ssn/track/issues/2
>> Raised by: Luis Bermudez
>> On product: sensor ontology - http://mmisw.org/orr/#http://www.w3.org/2009/SSN-XG/Ontologies/SensorBasis.owl 
>>  - 09.12.15
>> In SensorML all systems are processes, but in our case we can say  
>> that all processes are systems. And all the other classes (types of  
>> systems and processes) should be subclass of both. Suggestion:
>> - Move Sensor to be subclass of Device
>> - Remove PhysicalSystem - not needed
>> - Move Device to be subclass of Process
>
> -- 
> Prof. Manfred Hauswirth
> Digital Enterprise Research Institute (DERI)
> National University of Ireland, Galway (NUIG)
> http://www.manfredhauswirth.org/
>


--------------
I have my new work email address: jgraybeal@ucsd.edu
--------------

John Graybeal   <mailto:jgraybeal@ucsd.edu>
phone: 858-534-2162
System Development Manager
Ocean Observatories Initiative Cyberinfrastructure Project: http://ci.oceanobservatories.org
Marine Metadata Interoperability Project: http://marinemetadata.org
Received on Wednesday, 16 December 2009 19:35:10 GMT

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