Dear Chris,
Yes I agree. One of the biggest temptations is to think that
terms mean what their English language definitions say. I have been having
difficulties with this in the ISO 8000 development, where there is a huge variance
between how people define terms like information and data (very abstract and
academic), vs what people actually describe as information and data.
Regards
Matthew West
Information Junction
Tel: +44 560 302 3685
Mobile: +44 750 3385279
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
http://www.matthew-west.org.uk/
This email originates from Information Junction Ltd. Registered
in England and Wales No. 6632177.
Registered office: 2 Brookside, Meadow Way, Letchworth Garden
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From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Chris
Partridge
Sent: 23 January 2009 15:37
To: '[ontolog-forum] '
Subject: Re: [ontolog-forum] Ontological Means for Systems Engineering
Matthew, Ian,
I think buried in here is something quite important, and I am
sure that we have discussed before.
One can roughly categorise two ways of analysing: speculative
and empirical.
Exaggerating slightly. The speculative approach is an armchair approach
that thinks we can get to the essence of things without leaving it. The
empirical approach looks at the evidence (in my case, this is often in legacy
systems).
In the speculative approach, analysts often fixate on a name –
e.g. system – and try and find its essence. They assume an almost Adamic
approach, assuming that some divine power has handed out the names of the
objects from our ontology. Or, more prosaically, that since we use the names
they (that is the type not the token) must consistently refer to something.
In the empirical approach, one looks at what the names are used
to name. As Ian pointed out, it is certainly true that people use different
tokens of a name in ways that turn out to give very different results – and Ian
has described how these can be disambiguated. One starts from a descriptive
perspective (within a top level framework), but may find that some revision is
required to get an accurate result. Once enough evidence has emerged (and
revision been done), then one can start trying to generalise these a level. At
this stage, a general pattern that covers all uses of the term may emerge (and
debate about what to call it), or it may become apparent that there are a
Wittgensteinian family of senses. What is key, is that our trust of the higher
level pattern is based upon the evidence from earlier use or more specific
patterns – and these play an important role in fixing the sense of the general
pattern. Without the earlier use, there is little or no evidence for higher
level pattern. This is why the evidence gathering is so important.
My suspicion is that a lot of use of terms like system have not
been submitted to sufficient empirical analysis to establish what they refer to
accurately. In the IDEAS workshop there was quite a lot of evidence to support
this view.
Regards,
Chris
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Matthew
West
Sent: 23 January 2009 14:59
To: ian@xxxxxxxxxxxxxxxx; '[ontolog-forum] '
Subject: Re: [ontolog-forum] Ontological Means for Systems Engineering
Dear Ian,
Then we can add a third class, call it “System” and put that
name in a NameType intentionally constructed by Matthew. The point was that the
name doesn’t matter as long as we can identify the extent of the class. For
example, I might decide to call the class you identified “widget”.
Extensionally, it’s the same class, I just give it a different name. Because
IDEAS/BORO has a sophisticated(ish) naming pattern, I know that when Canadians
say “system” they are referring to a different class to the one you call
“system”.
We didn’t have the option to impose a new definition of “system”
on any of the parties.
[MW] That’s fine. My approach is usually to try to find the most
general sense, and then qualify it to produce the more restricted senses. This
has the advantage of giving you a model that shows the relationships
between them.
They had their own definitions, and a tiny ontology project was
going to stop the combined systems engineering departments of some the largest
defence agencies in the world from doing things their own way. The same goes
inside companies, I should add. This is why corporate taxonomies are all
given a stiff ignoring by the users, and one of the reasons why all those
“corporate data model” projects of the 1990s ended up producing something
no-one ever used. Either the users don’t agree with the terminology (in which
case, they dismiss it off hand), or they see a word they think they recognise
and use the model/taxonomy in an unexpected manner.
[MW] Which is why with the DDM we (including you) tried hard to
preserve the meaning the business gave to terms, but place them in the ontology
such that they were correctly defined by the relationships they had to other entity
types (especially subtype/supertype).
Regards
Matthew
West
Information Junction
Tel: +44 560 302 3685
Mobile: +44 750 3385279
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
http://www.matthew-west.org.uk/
This email originates from Information Junction Ltd. Registered
in England and Wales No. 6632177.
Registered office: 2 Brookside, Meadow Way, Letchworth Garden
City, Hertfordshire, SG6 3JE.
Cheers
--
Ian Bailey
www.modelfutures.com
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Matthew
West
Sent: 23 January 2009 13:26
To: ian@xxxxxxxxxxxxxxxx; '[ontolog-forum] '
Subject: Re: [ontolog-forum] Ontological Means for Systems Engineering
Dear Ian,
<snip>
The big challenge in ontology is to figure out what’s different
about a system to any other physical item.
[MW] I agree
Why is a car considered a system, but a rock isn’t, for example.
We had a lot of debates around this in IDEAS meetings. You can easily
ascertain the extents of aircraft, armoured vehicles, etc., but the extent of
the classes each nation were calling system differed. The UK framework (MODAF)
saw a system as any kind of man-made object that had functionality (i.e.
cars=yes, rocks and humans = no). The Canadians were very specific that a
physical object only became a system when it was manned, maintained and ready
to function – a narrower set than the UK one. The US (DoDAF) description was
similar to the UK but also included humans/animals. So, we had three
overlapping classes, each of which was called “system” by different parties. By
extensional analysis, we worked out that what MODAF calls
“CapabilityConfiguration” was an exact match for the Canadian “System”.
[MW] Well I don’t think any of those are wrong, but perhaps a
little restrictive. The two things that characterise a system for me are:
1.
It has a
function/capability/purpose.
2.
Has parts that can be
replaced by functionally equivalent parts.
Regards
Matthew
West
Information Junction
Tel: +44 560 302 3685
Mobile: +44 750 3385279
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
http://www.matthew-west.org.uk/
This email originates from Information Junction Ltd. Registered
in England and Wales No. 6632177.
Registered office: 2 Brookside, Meadow Way, Letchworth Garden
City, Hertfordshire, SG6 3JE.
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