1. Expert System Dr. Khoerul Anwar, S.T.,M.T STMIK Pradnya Paramita
alqhoir(at)stimata.ac.id
(c) 2017

2. What is Expert System
Expert system is one of the sub-discipline (Turban et al 2001) of artificial intelligence
An expert system also known as knowledge based system is a computer program that contains the knowledge and analytical skills of one or more human experts in a specific problem domain.
The goal of the design of the expert system is to capture the knowledge of a human expert relative to some specific domain and code this in a computer in such a way that the knowledge of the expert is available to a less experienced user

3. Characteristic Expert Non Expert
Memiliki pengetahuan {mengerti, mempraktekan, menjelaskan} banyak hal (detail) tentang hal khusus
Sedikit tau tentang banyak hal (mengetahui banyak hal, namun hanya sepintas saja atau dipermukaannya saja)

4. Specific Domain No Fied Expert 1 Medical Heart Eye Stomach Nerve
Pregnant
Berast cancer
etc 2
agriculture
Rice pests 3
fishery 4
computer
Network
Database
scurity

5. Definitions
Goodall’s (1985) : “An expert system is a computer system that uses a representation of human expertise in a specialist domain in order to perform unctions similar to those normally performed by a human expert in that domain”.

6. When to use an Expert System
If great costs are involved when making the decision
When applied to repetitive problem domains, the task must be performed often
When a big difference exists between the best solution and the worst solution
When test data is easy available to test and validate the ES
When there is a general agreement on the system’s conclusions. Errors in the input should be tolerated in the system output. Experts must agree on the solutions.
When recognised expertise is available and a necessity during the development of the ES
If the problem is clearly specifiable in the area of expertise i.e. what the system is supposed to do before it is done, the desired system can be developed

7. Cont..
If the problem is identifiable with a human expert, that is based on human expertise. Experts must perform the task substantially better than non-experts. The human expertise must be scarce.
If the problem domain is well bounded: for example defining criteria to determine the subject matter within the system from the matter outside of the system: The task is reasonably stable and within an acceptable narrow domain.
If solving the problem is based on knowledge rather than common sense reasoning: ES is based on knowledge and naïve systems on reasoning.
The solution has to be possible, justifiable and concisely generated (using only a few hundred rules), and
The knowledge has to be of a cognitive style and independent of common sense. Physical activities are ruled out.

8. ES in Solving Problems Interpretation Prediction Diagnosis Debugging
Design
Planning
Monitoring
Instruction, and
Control

9. Advantages of Using an Expert System
It improves the quality of the system
It can handle uncertainties expressed as probabilities
It explains the logic behind its recommendations, making the knowledge explicit
It can be used as a training vehicle for users who lack the expertise
It provides monetary savings once implemented.
Experts are freed enabling them to focus on tasks requiring their expertise

10. Cont…
It can codify and preserve knowledge of the specific problem domain.
It increases programmer productivity.
It can discover new knowledge
It can provide increased output and productivity.
It eliminates the need for expensive equipment used by human experts for monitoring and control
It makes knowledge and information accessible, and

11. Cont… It can outperform human experts because of the fact that ES:
Make fewer errors
Do not become tired or bored and never sleeps.
Will not overlook a solution
Can handle large volumes of data
Can respond more rapidly
Can function in hostile environments such as deep-sea drillings and reactor control, and
When the knowledge of several experts is integrated, it can outperform any one expert

12. ES Components

13. Components Knowledge base : Working storage : Inference engine :
contains the knowledge necessary for understanding, formulating and for solving problems.
A declarative representation of the expertise; often in IF THEN rules, frames, logic, semantic net and case etc.
Both factual and heuristic knowledge (less rigorous, more experiental, more judgmental knowledge of performance, rarely discused and large individual)
Working storage :
The data which is specific to a problem being solved
Inference engine :
the code at the core of the system which derives recommendations from the knowledge base and problem specific data in working storage. Inference Engine is a brain of expert system (Here two approaches are used i.e. forward chaining and backward chaining).
User Interface :
the code that controls the between the user an the system
provides facilities such as menus, graphical interface etc. to make the dialog user friendly

14. Roles of individuals who interact with system
Domain expert : The individuals who currently are experts in solving the problems; here the system is intended to solved
Knowledge base : the individual who the expert’s knowledge in a declarative form that can be used by the expert system
User : the individual who will be consuliting the system to get advise which would have been provided by the expert.

15. ES life Cycle

16. Characteristics of an Expert System
Expert system provides the high-quality performance which solves difficult programs in a domain as good as or better than human experts.
Expert System possesses vast quantities of domain specific knowledge to the minute details.
Expert systems apply heuristics to guide the reasoning and thus reduce the search area for a solution.

17. Cont..
A unique feature of an expert system is its explanation capability. It enables the expert system to review its own reasoning and explain its decisions.
Expert systems employ symbolic reasoning when solving a problem. Symbols are used to represent different types of knowledge such as facts, oncepts and rules.
Expert system can advice, modifies, update, expand & deals with uncertain and irrelevant data