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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: Thu, 17 Dec 2009 00:11:08 -0800
Cc: Semantic Sensor Network Incubator Group WG <public-xg-ssn@w3.org>
Message-Id: <DD8BCA9C-35C3-4920-9641-02AB872614CD@mindspring.com>
To: Manfred Hauswirth <manfred.hauswirth@deri.org>

On Dec 16, 2009, at 12:00, Manfred Hauswirth wrote:

> Hi John,
> thanks for your insightful comments. Some more comments from my side.
> John Graybeal wrote:
>> > 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.
> Interesting! I think this may be due to our different background (I  
> assume your are not a computer scientist like myself - without  
> evidence I may add).

Computer Science and Statistics. 30 years software and systems  
support.  (No worries!)

> In my area (computer science, information systems) systems would be  
> defined as I do and a system would consist of software and hardware  
> and the processes would clearly be "inside" the system as part of  
> the software, so there is a clear distinction between "system" and  
> "process" (other CS/IS people - please feel free to contradict me),  
> whereas you seem to define this more from the viewpoint of an  
> experiment which is being observed (?) where processes come into  
> play as part of the observation process (please correct me - I am  
> guessing here).

I'm using one of the general meanings of the word 'process', which  
applies not just to what's happening in side the computer or  
component, but what happens as all the software and components  
interact with each other.  There are local processes and there are  
external processes.

It isn't driven by experiment orientation but by broader CS  
orientation -- dealing with engineering systems of systems, and  
including the human component in those systems, and modeling all the  
above as processes (which may, or may not, then be computerized in the  
new version of the system).  Anyway, just a different viewpoint,  
neither right nor wrong.

> The problem here seems to lie in different conceptualizations in  
> different communities - all of which done according to the specific  
> needs of a community. Now, while this may complicate things, I think  
> it is also a useful and actually mandatory exercise. While I may  
> claim, that I need to understand the conceptualization because as an  
> CS/IS person I will have to build (software/hardware) systems  
> (sorry! no other term comes to mind) which need to manage  
> information coming out of observations, you may claim exactly the  
> same from you point of view (and rightfully so). The question now  
> for me is: Who are our users and how to serve them best? Where's the  
> sweet spot?

Concur. I presumed from the start that the group was interested in  
modeling hardware elements, but I have found it useful to consider  
those hardware components as processes in a larger system of systems.  
They take data in and transform it to other data that is spit out.  
This is one useful definition of a process, as Luis notes.

Oops, got off track there! But our agreed point is to agree on which  
type of devices (= which group of users) we want to make the ontology  
for.  My assumption/preference was the group that used physical  
devices to transform measurable phenomena into digital data (because  
that's the easiest to model and the most immediately useful).  But I  
can go with whatever on this, as long as we all understand.

>> > 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.)
> Agreed. But "sensors" do not necessarily manifest themselves as  
> hardware. If I want to detect user activity / inactivity on a  
> computer in an experiment, one of my sensors may be a the keyboard,  
> another one running processes (not waiting for user input), etc. It  
> is very hard to draw the line here. My question: Do I have to have  
> this distinction at all? Essentially I convert an X into a Y and Y  
> should be usable in a computer. Whether X a is a physical phenomenon  
> or not depends on the domain, IMHO.

Sure, that works for me too.  If you make a sensor too general,  
though, it can have components. What do we call those components --  
are not at least some of them sensors?  So now, what is different from  
the sensor that can have sensors, and a device, which has the same  
recursion into smaller devices; and a system, which can have systems  
(and a process, that can have processes)?

I'm being a little silly of course.  All I mean to do is call  
attention to the need to define the terms according to what makes them  
different from each other, not just whether they are higher or lower  
in a hierarchy. I think we haven't done that well enough yet.

>> 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.
> If you see software as a Device, I would agree to it, but then again  
> Device has the connotation of hardware.

Ah, I said a Sensor was hardware in my original world, so I didn't  
have any problem here -- since my Sensor was hardware and my Device  
had a sensor, I was already on board with Device being hardware.

>> Do we have a set of definitions by any chance, so we can all use  
>> these (or some) terms the same way?
> I don't think we have.
>> > 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.
> Sorry, but I don't understand how a Device can be a Process.

The "Process: something that receives an input and produces an output"  
is not a sufficient explanation or model of that?


> Best regards,
> Manfred
Received on Thursday, 17 December 2009 08:11:43 UTC

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