Major Characteristics of an Expert System
The Structure of an Expert System
The established definition of an "expert system" relies on the main abilities ascribed to human "experts", viz., they have specific expertise in some area(s). This expertise can be categorized as having "domain knowledge" and some ability (innate, learned, etc.) to apply that knowledge to solve problems within the domain.
An important realization in the design of software soltions: techniques employed by "automatic devices" (computer hardware, software, mechanical devices, automobile-airbags, expert systems) provide simplifications of possible solutions to a simplification of the problem. These simplifications are necessary because the real process may
The human model (of intelligent behavior) is partially explainable by:
The computerized model follows a similar design:
|Expert System||Traditional Program||Working memory||Variables||Knowledge Base||Files||Inference Engine||Program logic|
Definition: knowledge base - the part of expert system that contains the domain (and possibly other types of) knowledge.
Definition: working memory - facts newly discovered (by inference from the knowledge base and other working memory contents; or from input to system.)
Definition: inference engine - algorithm which uses knowledge base and working memory to infer (items are then added to the working memory, or sometimes to the knowledge base.)
Components of an Expert System
The following may not be actually delimited in an examination of a particular expert system:
The following is sometimes omitted from definitions of an expert system, but is usually considered necessary:
What about neural networks?
Characteristics of an Expert System
nonexperts outnumber experts in a field by 100 to 1
characteristics of an expert: adept at
Definition: knowledge engineering - the process of building an exp. system.
K.E. essentially includes
Steps in the knowledge engineering process (cf., waterfall and spiral methods of software design)
Phase 1 <-------- reformulation ------------------ Assessment | | | Requirements | | V | Phase 2 | <-- Explorations ------ | Knowledge Acquisition | | | | | Knowledge | | | V | | Phase 3 | | <- refinements ------ | | Design | | | | | | | Structure | | | | V | | | Phase 4 | | | ------------------------------------- | Test | | | Evaluation | | V | Phase 5 | | Documentation | | | Product | | V | Phase 6 | ----------------------------------------- Maintenance
Waterfall Development Model
Wikipedia explanation of waterfall model
Spiral Development Model
Wikipedia explanation of spiral model
Agile Software Development Model
Wikipedia explanation of Agile Software Development model