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Re: LANG: What does "simpler" mean?/ Input for f2f

From: Deborah McGuinness <dlm@KSL.Stanford.EDU>
Date: Sun, 07 Apr 2002 23:07:57 -0700
Message-ID: <3CB133BD.81ABC711@ksl.stanford.edu>
To: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
CC: www-webont-wg@w3.org
My main point of this message is to make a plea for a simple enough language in
the simplest of our lite language(s).
The reason for my plea is in talking to a number of users and potential users, I
am consistently getting feedback that DAML+OIL is too hard to understand/hard to

I think we should be making a lite layer with the goal of understandability and
broad usage (this is inline with Frank's email below.)
If we get clear on what the criteria should be for allowing a construct to be put
into the lightest layer, then we will have an easier time making the choices.
Right now, i believe the lite frame layer is too heavy.

I would make this argument separately from making the argument for a certain
number of layers.

My strongest point is that the light layer should be simple enough to be used by
the masses.
Operationally I claim that means
    - frame syntax can be used
    - broadly used frame-like expressive power is included
    - represenational notions that are difficult to explain/use are reserved for
heavier layers

My second point/suggestion is to first observe that frame systems appear to have
broad acceptability.  Thus I fully support the notion that the light layer should
have a frame feel.
I would find it acceptable to have two frame layers -
    1 - the light frame layer - this only has simple notions but still of course
has more than rdfs
    2 - the heavy frame layer - this contains many things that one can express in
a frame syntax but includes some of the more difficult constructs.  this includes
things such as cardinalityq

as an offer, I am willing to take co-editorship responsibility for getting a
document out that is presumably the followon to the document at:


Frank van Harmelen wrote:

> There was some discussion at an earlier teleconf on what the deciding factor
> was to put something in the "Lite" part of the proposed language.
> I argued that the "Lite" part was "simpler", without being very clear on what
> "simpler" meant.
> A telephone conversation with Deb McGuinness prompted me to be more explicit
> about this design goal of the "Lite" layer. (I'm not speaking for Peter or Ian
> here...)
> Frank.
>     ----
> The OWL Light subset was intended to be simpler than Full OWL in some
> way. There was some discussion at the teleconf what "simpler" meant.
> It means "conceptually simpler",
> not "syntactically simpler",
> not "computationally simpler".
> - CONCEPTUALLY SIMPLER. The goal was to make a subset of Full OWL
> that was conceptually easy to understand by our target group, and that
> made it easy to say things that users want to say often.
> This is also the reason why OWL Light contains "shorthand notations"
> for things that could already be said in longhand. The shorthands are
> meant to make it easy to say and understand the things that people
> want to say often.
> - SYNTACTICALLY SIMPLER: This was >*not*< the simplicity we were
> striving for. In fact, I think it is unlikely that the OWL Light will
> have a much simpler grammar than Full OWL. I think it will be
> somewhat simpler through the lack of nested expressions (the
> <description>'s in [1]), but not much.
> - COMPUTATIONALLY SIMPLER: Again, this was >*not*< the simplicity we were
> striving for. Although OWL Light is in fact less expressive than Full
> OWL, this was not our main driving force.
> [1] http://www.cs.vu.nl/~frankh/spool/OWL-first-proposal/

 Deborah L. McGuinness
 Knowledge Systems Laboratory
 Gates Computer Science Building, 2A Room 241
 Stanford University, Stanford, CA 94305-9020
 email: dlm@ksl.stanford.edu
 URL: http://ksl.stanford.edu/people/dlm
 (voice) 650 723 9770    (stanford fax) 650 725 5850   (computer fax)  801 705
Received on Monday, 8 April 2002 02:08:47 GMT

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