The document discusses expert systems, which are computer programs that use knowledge and reasoning to solve complex problems. It describes the basic components of an expert system as the knowledge base, inference engine, and user interface. The knowledge base contains facts and rules, the inference engine draws conclusions from the knowledge base, and the user interface allows for interaction. Expert systems offer benefits like availability, consistency, and cost-effectiveness compared to human experts, but also have limitations such as limited domains and difficulty maintaining knowledge. Examples of applications include diagnostic tools, medical diagnosis systems, help desks, and making financial decisions.

1. EXPERT SYSTEM
System Analysis And Design
Presented By:12bs(cs)02
Date:5th Sep 2014
Computer Science Department , QUEST

2. Overview
Expert System?
Basic Components
Characteristics
Benefits
Pit false
HS v/s ES
Why use ES?
Problems with ES
Applications
2 5 September 2014
12bs(cs)02 System Analysis And Design

3. 3 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2014

4. Expert System
An intelligent computer programme that uses knowledge
and reasoning procedures to solve difficult problems that
need certain expertise to solve the problems
"ES is developed to model the ability of an expertise in
solving problems. In the process of modelling the method
which an expert uses to solve a problem, ES must be
able to provide users with the services and facilities that
an expert can usually provide
User supplies facts or other information to the expert
system and receives expert advice or expertise in
response
4 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 014

5. Basic Components of Expert System
The Knowledge-Base contains the knowledge, it is the
collection of facts and rules(IF ,THEN) which describe all the
knowledge about the problem domain .
Knowledge Representation is represented in a computer in
the form of rules ( Production rule).
Consists of an IF part and THEN part .IF part lists a set of
conditions in some logical combination.
If the IF part of the rule is satisfied; consequently, the THEN part
can be concluded
The Inference Engine draws conclusions from the knowledge
Expert System User Facts Expertise Inference Engine
Knowledge-base, is the part of the system that chooses which
facts and rules to apply when trying to solve the user’s query
5 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 14

6. Cont...
The User Interface is the part of the system which takes
in the user’s query in a readable form and passes it to the
inference engine. It then displays the results to the user
Interpreter Through the user interface, interpreter
explains user questions, commands and other
information generated by the expert system, including
answers to questions , explanations and justifications for
its behaviour , and requests for data
Blackboard To record intermediate hypotheses and
decisions that the expert system manipulates
6 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 14

7. Note
Note: Almost no exiting expert system contains all
the components shown above, but some
components, especially the knowledge base and
reasoning machine, occur in almost all expert
systems. Many ESs use global database in place of
the blackboard. The global database contains
information related to specific tasks and the current
state.
7 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 14

8. Characteristics Of ES
Expert system is capable of handling challenging
decision problems and delivering solutions.
Expert system uses knowledge rather than data for
solution. Much of the knowledge is heuristic based rather
than algorithmic.
Expert system has the capability to explain how the
decision was made.
Explain their reasoning or suggested decisions
Display intelligent behaviour
Draw conclusions from complex relationships
Provide portable knowledge
Expert system shell : A collection of software packages
and tools used to develop expert systems
8 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 14

9. Benefits
It provides consistent answer for repetitive decisions,
processes and tasks
It holds and maintain levels of information
It clarify the logic of decision making
It cannot needs human, it works continuously
A multi user expert system can serve more users at a time
It reduces the cost of consulting experts for problem solving
It provides quick and efficient solutions to problems
It offers high reliability of expert suggestions or decisions
It can tackle very complex problems that are difficult for human
experts to solve
It can work on standard computer hardware
It can not only give solutions, but also the decision logic and
how the solution was arrived at.
9 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 14

10. Pit false
Not widely used or tested
Cannot readily deal with “mixed” knowledge
Possibility of error
Difficult to maintain
May have high development costs
The knowledge base may not be complete
Each problem is different. Hence the solution from a
human expert too may be different
Expensive to build and maintain
Takes long time to develop and fine tune ES
Large ES is difficult to build and maintain
10 12bs(cs)02 System Analysis And Design 5 September 2014

11. ES v/s HE
11 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 14

12. Why use Expert Systems?
Experts are not always available. An expert system
can be used anywhere, any time
Human experts are not 100% reliable or consistent
Experts may not be good at explaining decisions
Cost effective
12 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 1 4

13. Problems with Expert Systems
Limited domain
Systems are not always up to date, and don’t learn
No “common sense”
Experts needed to setup and maintain system
13 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 1 4

14. Applications
Diagnostic tools for fixing machinery and vehicles
Online medical system for diagnosing problems
Telephone based help desk
Finance firm making loan/credit decisions
Government services such as working out tax &
benefits
14 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2014

15. THANKYOU 
15 12bs(cs)02 System Analysis And Design 5 S e p t e m b e r 2 0 14