- From: Manfred Hauswirth <manfred.hauswirth@deri.org>
- Date: Tue, 22 Dec 2009 19:10:40 +0000
- To: Luis Bermudez <bermudez@sura.org>
- CC: John Graybeal <jbgraybeal@mindspring.com>, Semantic Sensor Network Incubator Group WG <public-xg-ssn@w3.org>
Looks fine to me. The only item I am really having trouble with is "a
sensor is a process". Since I wanted to test, if I am the only person
who could not understand this, I tested it around here: 100% had the
proverbial question marks written on their faces (mostly CS people, some
with a science back ground - physics).
Just wanted to flag this. Seems a pretty strong indicator to me though.
However, If this is the consensus of the group it to go with it, I am OK
with it (still feels strange for me though).
Cheers,
Manfredd
Luis Bermudez wrote:
> Can we make some conclusions, in particular those of you discussing this
> thread ?
>
> I agree with all of these:
>
> - A process has inputs and outputs
> - A system has components
> - A sensor is a process
> - *Some* devices are sensors
> - *Some* devices are systems
>
>
> -luis
>
> On Thu, Dec 17, 2009 at 3:11 AM, John Graybeal
> <jbgraybeal@mindspring.com <mailto:jbgraybeal@mindspring.com>> wrote:
>
>
> 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?
>
> John
>
>
> Best regards,
>
> Manfred
>
>
>
>
>
>
> --
> Luis Bermudez Ph.D.
> Coastal Research Technical Manager
> Southeastern Universities Research Association (SURA)
> bermudez@sura.org <mailto:bermudez@sura.org> - Office: (202) 408-8211
> 1201 New York Ave. NW Suite 430, Washington DC 20005
--
Prof. Manfred Hauswirth
Digital Enterprise Research Institute (DERI)
National University of Ireland, Galway (NUIG)
http://www.manfredhauswirth.org/
Received on Tuesday, 22 December 2009 19:11:22 UTC