Expert systems have been available from a number of sources. They have been used with some success in a number of areas: machine tool selection, chromosome analysis, fingerprint analysis and classification and remote sensing application, to mention a few.

A notable real life application of expert systems has been in fault finding and preventive maintenance of complex semi conductor device manufacturing plants. Whenever there is a problem, experts from diverse areas have to analyze, discuss and agree on remedial action. All this could take days if not weeks! The plant would need to be shut down. This becomes very expensive because, it takes very long to achieve the exact operating conditions required for start up. An expert system, on the other hand, can quickly detect even minor deviations in the performance of the plant, much before anything really goes wrong. To diagnose the problem, it uses a wealth of knowledge obtained from experts in diverse areas pertaining to the plant. It then advises the engineers how to correct the fault. All this happens in minutes, without a shut down.

How do we understand Human Intelligence - as in Vision?

Understanding human intelligence would seem to be a prerequisite for achieving artificial intelligence. It is also interesting in its own right. For instance, how does our faculty of vision work? Animal studies turned out to be very useful for understanding this. Hubel and Weasel projected simple pictures of various kinds before the open eyes of live cats and analyzed the signals passing through their brains - the visual cortex and other parts of the vision chain. To facilitate this, they cut open their brains to start with. This gave us a lot of information (poor cats!).

Another method that researchers used was to show various patterns to humans and ask them to introspect (do loud thinking) while they see and interpret the picture in front of them.

Speech is a difficult subject to understand
How does one understand how humans recognize or understand speech? Cutting up animals and probing their brains will not help because they can't speak. In fact, human brains have a special speech processing centre which animals do not have. It is illegal to cut up humans and make them listen to various sounds, so even this method is ruled out!

A further problem is that the human speech system is not amenable to introspection, so even this avenue is closed. A human subject realizes that he recognizes the letter 'H' (for instance) when he sees two vertical lines and a horizontal line connecting them. He cannot make a similar analysis of how he recognizes the syllable 'Kay' that he hears, in terms of its component parts. In fact, if you played out the three components (the first, second and third formants) of this syllable separately, the listener will not be able to relate them to the composite sound in any manner. The brain recognizes the totality as the particular syllable. It is an all or nothing kind of recognition. You cannot recognize the components as being part of it. Surely, this happens in the brain but awareness of the individual components is not accessible for introspection. The speech processor of the human brain is a locked black box. You cannot probe into its actual working.

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