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Re: SOSA core - procedures vs devices

From: Krzysztof Janowicz <janowicz@ucsb.edu>
Date: Tue, 12 Jul 2016 22:25:38 -0700
To: Simon.Cox@csiro.au, jlieberman@tumblingwalls.com
Cc: danh.lephuoc@tu-berlin.de, armin.haller@anu.edu.au, public-sdw-wg@w3.org, kerry.taylor@anu.edu.au
Message-ID: <5785D0D2.2000105@ucsb.edu>

I would propose the following:

1. A Procedure describes the *workflow* used to perform (carry out) the 
act of observing/sensing. The simplified example I used today was 
temperature. One procedure will require to mount a thermometer 2m above 
ground in an area that is neither directly exposed to sun or wind. 
Another procedure will use the very same sensor type (thermometer) but 
explain how to place it within a certain layer of soil. In the first 
case, the observed property is air temperature; in the second case, it 
is soil temperature. Procedures are key to interoperability and the 
*reproducibility* of results. This notion of a procedure aligns well 
with Gil's work on workflows as well as provenance work more broadly. In 
the SSN-SSO pattern we stated that an Observation /satisfies/ a 
(observation) Procedure and that a Sensor /implements/ such Procedure. 
There are several types (subclasses) of Procedure. I can think of at 
least two: SamplingProcedure and ObservationProcedure.While this may 
sound trivial, please note that a single procedure is used to carry out 
*millions* of observations in the same way as one uses the same recipe 
over and over again to bake a chocolate cake.

2. The act of using a Sensor to arrive at a Result for an 
ObservedProperty of a FeatureOfInterest by receiving some Stimulus is 
what I would call Sensing/Observing (see also 
https://www.w3.org/2005/Incubator/ssn/ssnx/ssn#Sensing).  IMHO, we do 
not need that level of detail in SOSA-core but certainly in other 
(vertical  & horizontal) modules. The *most* important aspect here is 
that every single use of a sensor creates a new (and unique) Sensing. 
This is why Procedure and Sensing are very different. There are 
thousands of (popular) procedures but billions of sensing acts. Why 
would one care about the act of sensing? One example would be to use it 
to capture contextual information, e.g., about the weather and its 
potential impact on a certain observation, other observations required 
to interpret the results, and so on. If I am not mistaken, this 
particular context is also known as ObservationContext.

3. So what Thing is carrying out this Sensing by following a certain 
Procedure? I believe that we should call this the *Sensor* and very 
explicitly state that humans can be sensors, devices can be sensors, 
simulations can be sensors, and so forth. This leads to the interesting 
question of whether we should subclass sensor and I would propose not to 
do so in SOSA-core. Given that we merely have the expressivity of RDF at 
our disposal, we do not want to end up with statements such as Human 
subClassOf Sensor. Even more importantly, I would not try to find a 
better name than Sensor. Terms such as Device will exclude humans and 
simulations and thus are too specific. Terms such as System are too 
broad. Sensors are things that perform sensing and humans clearly do so, 
e.g., with their eyes.

4. Try to avoid terms such as process and event whenever possible.

What do you think? Does this make sense?


On 07/12/2016 04:50 PM, Simon.Cox@csiro.au wrote:
> Yes, but I think we were thinking more that a procedure uses a device, 
> during an activity.
> When describing the agents of observation, it depends how close you 
> want to look. There are multiple layers of encapsulation. That was 
> probably the motivation for bundling them together in SensorML and 
> O&M, but SSN chose to be more careful about distinguishing physical 
> devices from workflows – which I certainly understand as well.
> The word ‘process’ is overloaded, and in particular is used in 
> contradictory ways in BFO and O&M, and SensorML uses it in both ways. 
> So now I prefer to avoid it altogether.
> *From:*Joshua Lieberman [mailto:jlieberman@tumblingwalls.com]
> *Sent:* Wednesday, 13 July 2016 9:10 AM
> *To:* Cox, Simon (L&W, Clayton) <Simon.Cox@csiro.au>
> *Cc:* danh.lephuoc@tu-berlin.de; janowicz@ucsb.edu; 
> armin.haller@anu.edu.au; public-sdw-wg@w3.org; kerry.taylor@anu.edu.au
> *Subject:* Re: SOSA core - procedures vs devices
> Sorry I missed the call today. So a device “runs” (l:n) a procedure in 
> / during (1:n) a process?
> —Josh
>     On Jul 12, 2016, at 6:39 PM, simon.cox@csiro.au
>     <mailto:simon.cox@csiro.au> wrote:
>     I’ve put some notes and a diagram explaining my understanding of
>     the consensus from today’s call here
>     https://www.w3.org/2015/spatial/wiki/SOSA_Ontology#Procedures_vs_Devices
>     Note
>     1.I have adjusted the names of the classes to avoid ambiguity
>     between the re-usable things and the events when they are used
>     2.I have not yet implemented this in SOSA-Core – its just a
>     proposal for now.
>     Simon

Krzysztof Janowicz

Geography Department, University of California, Santa Barbara
4830 Ellison Hall, Santa Barbara, CA 93106-4060

Email: jano@geog.ucsb.edu
Webpage: http://geog.ucsb.edu/~jano/
Semantic Web Journal: http://www.semantic-web-journal.net
Received on Wednesday, 13 July 2016 05:26:12 UTC

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