SUO: FW: RE: Resolution of Comment #1 "Target Number of terms"
This from Graham Horn bounced, so here it is again:
-----Original Message-----
From: Horn, Graham [mailto:graham.horn@aihw.gov.au]
Sent: Wednesday, August 23, 2000 22:40
To: 'Schoening, James R CECOM DCSC4I'
Cc: Standard-Upper-Ontology (E-mail)
Subject: RE: RE: Resolution of Comment #1 "Target Number of terms"
James,
. At the risk of being repetitive, may I ask why we cannot
start by seeing what the work demands.
. Nevertheless, I suggest we should NOT ignore the discussion to date
on this point, but keep it firmly in mind.
. I suggest we should be focusing on functionalities and areas of
coverage, and monitoring the implications of the extents to which various
options are included.
. It may, in early stages, appear that particular lines of approach
are going to require great complexity, until one or more simplifying
techniques are uncovered. During such a phase, the scope could look, at some
stages, like heading too large, and at other stages being troublingly small.
. In any event, I haven't seen any evidence that allows any prediction
of what our subject domain will DEMAND. By this I mean that no-one seems to
have provided any analysis of what aspects or areas will require how many
items. All I have seen so far, and the message below is an example, is
people quoting specific examples of specific systems. If anything, tho',
these tend to suggest that 300 is likely to be insufficient for a
non-trivial system. I admit I haven't had the time to go through many of the
e-mails other than read what appears in the "preview" box of my e-mail
browser - tho' I have saved ALL of them.
. I don't see any indication that we have any particularly good way of
being able to predict what we are aiming at will require. If we can predict
this to within an order of magnitude, I suggest we are doing well.
. I suspect that the subject domain is SO large that the best approach
may be to look at a perspective which is different to, but not necessarily
incompatible with, the various systems around that have already been
developed, such as those already quoted.
. However, if that does not seem to provide a worthwhile path, then
perhaps we should be looking at an approach that tries to cover
"everything", and touches lightly on (and thereby hopefully provides
potential links to) the various systems around today. (I might add that the
problems associated with compatibility among "STEP compliant" systems, which
were around for some years, amounted to a frustratingly troubling matter,
and strike me as a potentially significant cause for concern. The systems
described below, relating to STEP, by Bill Burkett strike me as being
somewhat akin to the provision of a dictionary of philosophy along with
every paragraph of a book, so as to ensure the reader properly interprets
the issues one is propounding. Surely it is possible to establish more
common ground, and be more efficient, than this - by paying close attention
to avoiding ambiguities and hazy terminology).
. I suggest the "Target Number of terms" should remain open, with
perhaps a guidance that less than 300 and more than 3000 should be
significant break points for review. I suggest that, say, 30,000 should be
seen as a further point at which there should be some serious review, with a
view to some process such as subdivision or specialisation / narrowing of
focus.
. I note that most discussion has centred on ten to the powers of 2.5,
3.5 and 4.5. Maybe we could narrow down what I just said to setting review
points to ten to the powers of 3 and 4, ie. 1,000 and 10,000.
Cheers Graham Horn
PS: I will try to get to subsequent Comments in the near future. Sorry for
my tardiness WRT them, I have been very busy on other matters.
Australian Institute of Health and Welfare
================================================
Phone: 02.6244.1094
Fax: 02.6244.1166
E-mail: Graham.Horn@aihw.gov.au <mailto:graham.horn@aihw.gov.au>
-----Original Message-----
From: Schoening, James R CECOM DCSC4I
[SMTP:James.Schoening@mail1.monmouth.army.mil]
Sent: Thursday, August 24, 2000 7:39 AM
To: Standard-Upper-Ontology (E-mail)
Subject: SUO: RE: Resolution of Comment #1 "Target Number of terms"
This message from Bill Burkett WBurkett@pdit.com bounced, so here it is
again:
I apologize to James for not letting "sleeping dogs lie", but the following
message came across my desk this morning and presents a more
practical-experience-based alternative to my argument for fewer concepts in
the SUO. I apologize for all the acronyms, but the gist of the message is
that implementing large numbers of classes is very problematic for data
access and interoperability.
"Dear Luis,
Yes the projects that tried to bind CORBA to the SDAI experienced big
problems because an SDAI binding of STEP requires many classes and most
(all?) CORBA implementation do not perform well when they are required to
send messages between hundreds of small classes.
The granularity problem is easier to deal with in the SDAI P27 using Java
serialization because all the classes are loaded into the local application.
However, a new problem arises because it takes a long time to load the Java
classes.
Also for both approaches there is a common problem of programmer
understanding. You have to be a STEP expert to write applications against
500 classes.
In consequence, the SDAI that is working well today is the SDAI C binding.
This binding is being used by STEP and geometry experts to write STEP
translators. Most of the major CAD systems contain a STEP translator written
using some variety of SDAI C binding.
The search for an "easy" interface for STEP programming continues. The
current focus is on using XML to provide this capability. The XML bindings
for STEP being developed in the Part 28 project give STEP data a much more
descriptive representation than Part 21 because all the attribute
information is repeated for every entity instance. With the right approach,
the XML data can be organized so that with a little knowledge you can read
the description and understand the meaning. This is a big step forward (pun
intended) because with Part 21 you need to have both an EXPRESS-G
description of the data and the STEP mapping tables in order to get any
understanding of the Part 21 information.
Lastly, by combining STEP XML with the Document Object Model (DOM) you can
build a new CORBA (or OLE/COM) interface to STEP that contains far fewer
classes, resulting in much better performance and easier programming."
------------------------------------------------------------------
William C. Burkett 562-495-6500x13
Product Data Integration Technologies, Inc. 562-495-6509
100 W. Broadway Suite 540 wburkett@pdit.com
Long Beach, CA, 90802 USA http://www.pdit.com
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-----Original Message-----
From: Schoening, James R CECOM DCSC4I
[mailto:James.Schoening@mail1.monmouth.army.mil]
Sent: Monday, August 21, 2000 12:35
To: 'Standard-Upper-Ontology (E-mail) '
Subject: SUO: Resolution of Comment #1 "Target Number of terms"
SUO,
It appears we do not have consensus to change the target size of SUO to
~300, as suggested in Comment #1(below) by Bill Burkett. Bill has stated
that while he is still uneasy about the
target size of 1000-2500, he is "...willing to go along with it given the
subsequent discussions about structuring, specialization, and organization
of concepts."
As such, unless anyone objects, we will stay with the original
target of 1000-2500.
Please also keep in mind that this is cited as an 'estimate.' If we
later find the best size is smaller or larger, we will not be bound by this
range.
Jim Schoening
-----Original Message-----
From: Schoening, James R CECOM DCSC4I
Sent: Monday, August 07, 2000 21:10
To: 'Standard-Upper-Ontology (E-mail) '
Subject: SUO Comment #1 Resolution
SUO,
SUO Comment #1: Bill Burkett writes:
"I believe that the objective of 1000-2500 terms is far too large to
be practical. In my experience, I've found that the practical upper limit on
the number of independent object/entity types in a schema is ~300 types.
Models larger than this simply cannot be comprehensively understood by a
single person. (One may argue that it's possible to understand larger models
with the aid of a meta-level organizing structure - and I agree - but then
*this* structure becomes the upper level ontology.)" ( The full text of
this message is located at
http://ltsc.ieee.org/records/suo-votes-2000-07-26.htm#bill)
One reply already posted was from Adam Pease, who wrote:
"Folks in the HPKB project including Cycorp, Teknowledge and Stanford used
the Cyc upper model of 3000 terms successfully in several tests. I take this
as an existence proof that refutes your assertion, or more gently, maybe it
just refutes the need for an individual to comprehend the entirety of a
model for that model to be useful."
This comment is now open for discussion. Is 1000-2500 too large? If so,
what would be a better range to target?
Jim Schoening