9. CONCLUSION 
In order to guarantee the high throughput and precision of the various ERS-1 
products one would need several highly skilly operators. To hire this kind 
of operator for the whole lifetime of the satellite would be very expensive 
and it is uncertain that they can solve the problem in an appropriate time. 
Therefore an expert system shall be used to support the operator. 
6. 
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Charniak, E., Mc Dermott, D., "Introduction to Artificial Intelligence" 
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3 
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Hayes-Roth, F., Waterman, D.A., Lenat, D.B., "Building Expert Systems", 
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