Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!ucsd!sdcsvax!ucsdhub!hp-sdd!hplabs!sdcrdcf!trwrb!aero!venera.isi.edu!smoliar
From: smoliar@vaxa.isi.edu (Stephen Smoliar)
Newsgroups: comp.ai
Subject: Re: Expert Systems in the Railroad Industry.
Message-ID: <5358@venera.isi.edu>
Date: 26 Apr 88 15:06:48 GMT
References: <8816@agate.BERKELEY.EDU> <73@edai.ed.ac.uk>
Sender: news@venera.isi.edu
Reply-To: smoliar@vaxa.isi.edu.UUCP (Stephen Smoliar)
Distribution: comp.ai
Organization: USC-Information Sciences Institute
Lines: 52
Keywords: AI, Expert Systems, Dynamic Programming, Appropriate Technology.

In article <73@edai.ed.ac.uk> ceb@edai (Colin Bridgewater) writes:
>In article <8816@agate.BERKELEY.EDU> lagache@violet.berkeley.edu (Edouard
>Lagache) writes:
>>
>>
>                                            ....for those interested in
>>     computers and trains: what sort of expert systems have developed for
>>     the railroad industry?  It seems to me that there are a number of
>>     promising areas:
>>
>>     1.)  Scheduling.
>>
>>     2.)  Optimal switching moves and train assembly.
>>
>>     3.)  Cargo routing and loading.
>>
>>     4.)  Equipment Maintenance.
>>
>>          Does anyone know of what work (if any) has been done by railroads
>>     or A.I. outfits in this area?  Interestingly enough, Dreyfus would
>>     probably claim that the first 3 areas would be very promising domains
>>     for expert systems.
>
>
>  Just to get my two penn'orth in, whatever happened to dynamic programming
>for scheduling, cargo-space optimisation and inventory control etc ?  This
>well-worn technique is quite adequate for the majority of purposes envisaged
>by EL. I mention this to raise a wider issue which was possibly not in the
>mind of the original sender, namely that of the desire to throw ever more
>complex solution procedures at the simplest of problems....
>
>  Why should we want to implement an expert system, when adequate techniques 
>exist already ? That is, is the application of expert system technology
>appropriate to the magnitude and complexity of the problem ? Should we be
>advocating the application of such 'high-tech' solutions to all and sundry ?
>I have no doubt that such systems could be made to work, don't get me wrong 
>on that, I just question whether the level of technology required in order to 
>do so is justified. Surely it is better to apply the simplest solutions when-
>ever possible.
>
There is one issue of "appropriate technology" which appears to have been
overlooked in Colin's argument;  and that is the matter of computational
tractability.  In many practical domains, while it is certainly possible
to build mathematical models which may then be processed by dynamic
programming, those models are too unwieldy to yield much useful information
in any reasonable period of time.  Often what makes an expert an expert is
the ability to recognize that a complex general-purpose model may be
considerably simplified through abstraction without significantly sacrificing
fidelity.  The mathematical nature of the model, in and of itself, cannot
provide us with information of how to perform such abstractions.  That is
often why we need experts;  and, in such cases, if that expertise can be
properly modeled by an expert system, a computationally intractable approach
can be turned into a practical one.