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ES Design, Development and OperationDr. Ahmed Elfaig
• Knowledge model, knowledge structure, presentation and
organization are the bottleneck of expert system development
• Knowledge model can be graphically illustrated to reflect the
component and integrated nature of different modules of the
problem domain.
• The conceptual model of the problem and the problem sub-module
are shown in the figure below:
ES Development Phases
• The testing phase aims at showing , validating and verifying the
model and software of ES functions.
• It shows the overall structure of the system and its knowledge
• (verification shows no bugs or technical errors)
• Traces syntax errors that may prevent the rules from firing and fixing
such errors
Goals of Verification
• Make sure there are no:• Bug• Technical errors• Removing errors• Incompleteness• Ambiguity• Inconsistency in system function
Knowledge Acquisition
• Knowledge acquisition : Is processes involve collecting, eliciting, organizing, analyzing and interpreting the knowledge that human experts use when solving particular problem
• Knowledge acquisition involve includes knowledge refinement, validation and verification.
Importance of Knowledge acquisition
Importance of knowledge come from the fact that :
• The power utility of any system depends on underlying knowledge quality
• The clients acceptance of the system depends on the validity of the knowledge it has.
Type of knowledge
• Declarative knowledge: which is used to describe the problem characteristics and concepts
• Heuristic knowledge: Knowledge used to make judgement or strategic rule of thumb.
VALIDATION
• Comparison of research output (knowledge) with the heuristic of expert in the field
• Comparison of the research output with known results
Content Validity
• Results of the system or research test against experts
• The system models test against other models
VALIDATION PROCESSES
• Known results: for example WHO• Blind performance test: Compare the results
against human experts• Face validation: Qualitative procedure to test
the results• Subjective evaluation: Evaluation of the
results through consultation with experts
Validation: Assessments ResultsParameters consideredMeanSTD
Variable:1.Completeness2.Importance
3.843.72
0.020.01
Output:1. Important results3.960.04
Performance:1.Right results2. Complete results
3.883.8
0.030.02
Explanation;1.Why certain variables are
needed
3.40.03