 SHORT DESCRIPTION OF  THE IMPSHELL  - 
                         AN EXPERT SYSTEM DEVELOPMENT ENVIRONMENT
 
 
 The IMP Shell is a powerful expert system development environment for
 the IBM PC.  It contains all the utilities needed to develop and test
 new expert  systems,  and run  them  when  they  are  finalized.  All
 functions are menu driven and appear in windows.   IMP expert systems
 are rule based,  backwards chaining systems.   They are very fast and
 not limited by an artificially small number of rules.
 
 The IMP Shell is in the public domain and is used in many educational
 settings.  It was developed  by Daniel H. Marcellus of the Middletown
 Programming  Works,  Middletown,  N.Y.  It is completely described in
 the book:
 
      D.   Marcellus, 
      Expert   Systems  Programming  in   Turbo  Prolog, 
      Prentice-Hall,
      Englewood Cliffs, N.J., 1987.
 
 An expert system is a program which has captured the expertise  of an
 expert  in  some field and  can deploy that expertise  with seemingly
 intelligent behavior.   For instance  there are expert  systems to do
 all these things:
 
 
      diagnose medical problems
 
      guide the repair of complex equipment
 
      give advice about taxes and investments
 
      guide chemists in synthesizing desired chemicals
 
      interpret telemetry data from satellites
 
      control nuclear reactors and electric utility grids
 
 
 A shell makes it easy to set up an expert system by  concentrating on
 the problem at  hand  rather  than  on  the details  of  a particular
 machine reasoning system or artificial  intelligence language.   This
 shell was written entirely  in TURBO  PROLOG,  and the source code is
 provided,  although you don't need to understand anything about TURBO
 PROLOG in order to set up an expert system with this software.
 
 The IMP Shell is menu driven,  and the menu allows you  to select all
 the  activities  that  are   necessary  at  various  stages   of  the
 development of an expert system, for example:
 
 
      1.   HELP information
      2.   MAKE rules for a new expert system
      3.   INSPECT the rule set that is loaded
      4.   SAVE the rule set that is loaded
      5.   LOAD an existing rule set
      6.   RUN the presently loaded rule set
      7.   EDIT an existing rule set
      8.   PRINT an existing rule set
      9.   DOS access
      10.  END this program
 
 
 The IMP Shell uses backward reasoning.   This means that  it has  the
 proper   architecture   for   creating   good   expert   systems  for
 classification  tasks,  for troubleshooting,  and, in  general,   for
 anything that involves choosing among   alternatives.    It   is  not
 the  proper  architecture  for  applications   that   require  a well
 defined sequence  of steps  with complex reasoning   going  into  the
 application of each step.   Applications such as configuring  complex
 equipment or  estimating costs of a project are of this  sort.   They
 should be implemented with a forward chaining shell.
 
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