Expert System
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Transcript of Expert System
EXPERT SYSTEMSystem Analysis And Design
Presented By:12bs(cs)02
Date:5th Sep 2014
Computer Science Department , QUEST
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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
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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
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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
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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
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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.
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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
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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
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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
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ES v/s HE
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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
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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
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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
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THANKYOU
5 September 2014
12bs(cs)02 System Analysis And Design