EXPERT SYSTEMSystem Analysis And Design

Presented By:12bs(cs)02

Date:5th Sep 2014

Computer Science Department , QUEST

2

Overview

5 September 2014

Expert System? Basic Components Characteristics Benefits Pit false HS v/s ES Why use ES? Problems with ES Applications

12bs(cs)02 System Analysis And Design

3 12bs(cs)02 System Analysis And Design

5 September 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

12bs(cs)02 System Analysis And Design

5 September 2014

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 12bs(cs)02 System Analysis

And Design 5 September 2014

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

12bs(cs)02 System Analysis And Design

5 September 2014

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.

12bs(cs)02 System Analysis And Design

5 September 2014

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

12bs(cs)02 System Analysis And Design

5 September 2014

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. 12bs(cs)02 System Analysis

And Design 5 September 2014

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

12bs(cs)02 System Analysis And Design

5 September 2014

11

ES v/s HE

12bs(cs)02 System Analysis And Design

5 September 2014

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

12bs(cs)02 System Analysis And Design

5 September 2014

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

12bs(cs)02 System Analysis And Design

5 September 2014

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

12bs(cs)02 System Analysis And Design

5 September 2014

15

THANKYOU

5 September 2014

12bs(cs)02 System Analysis And Design