Page 192 - DCAP506_ARTIFICIAL_INTELLIGENCE

Artificial Intelligence

Notes 5. They needed more powerful hardware than a microcomputer – usually, a workstation.
Historically, ES shells have been more constrained, perhaps offering only a single kind of
knowledge representation. They would usually be designed to run on a PC.
6. However, in recent years, ES shells have become more sophisticated, and added multiple
forms of knowledge representation and of inference strategy. PCs have become more
powerful, and PC versions of ES environment software have been released.

Notes It is probably not useful to make the distinction any more. One could simply speak
of “simple shells” and “sophisticated shells”.

13.7.3 Advantages and Disadvantages of Expert System Shells

Advantages

The programming effort that has gone into building the user interface and inference engine is
reused:
1. The level of programming skill needed to produce the finished system is much lower than
it would be if the system was programmed from scratch using a language.

2. This means that, if an appropriate shell is chosen, the project can be completed faster, and
cheaper.

Disadvantages

1. ES tools are “end-user tools”. Compared with systems programmed from a language,
such software packages tend to produce systems that have:
(a) poor documentation
(b) weak security
(c) difficult maintenance problems

2. If the shell is a poor match for the type of knowledge in the domain concerned, it is liable
to produce a system which simply doesn’t correspond to the expertise of the original
domain expert.
3. In an attempt to model a non-standard piece of reasoning, the system builders by side.
Such a “system” is bound to be unsatisfactory, and to lead to problems of use, maintenance
and training.

Self Assessment

Fill in the blanks:
12. A ....................... is a complete development environment for building and maintaining
knowledge-based applications.
13. The ................................ is a command line interpreter developed by Byron Rakitzis and
Paul Haahr, that uses a scripting language similar to the rc shell of the Plan 9 operating
system.

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