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Transcript of Lahore University of Management Sciences, Lahore, Pakistan Dr. M.M. Awais- Computer Science...
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Life CycleLife Cycle
Life Cycle of a Classical Software Development
Requirement Analysis
Design Implement
Test /Maintenance
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Problems Problems
Traditional Life Cycle model is Linear
Every Step can be completed before the next starts
Requires exact understanding of the problem at the start of the project
Ability to trace back to the original requirements
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Expert System Life CycleExpert System Life Cycle
Basic Principle:
Iteration are inevitable Why?
No body understands the problem exactly
The problem becomes severe when the system under consideration is Knowledge based
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
ES Development Life CycleES Development Life Cycle
ProblemSelection
PrototypeConstruction
Formalisation
Implement EvaluationLong-Term Evolution
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Unique Characteristics Unique Characteristics
Customer is involved through out the process
Frequent Demonstrations are encouraged
Change is viewed as healthy
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Details: Problem Selection Details: Problem Selection
Problem Survey
Candidate Selection
Candidate AnalysisDomain Applicability
Expert Availability
Problem Scope
Cost/benefit Analysis
Final Candidate SelectionTask Characteristics (defining the nature of the ES)
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Details: Problem Selection Details: Problem Selection
Candidate Selection
Does the task require expert knowledge?
How much benefit the system will be to the organisation.?
Is the solution valuable for long time to the organisation.?
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Problem Selection: Example Problem Selection: Example
Black Board ArchitectureUsed for problems when knowledge acquisition is done from different sources
Rule and Control SchemeUsed under conditions when exact rules can be defined for a problem. The scope of application is also limited
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Problem Selection: Example Problem Selection: Example
An expert System has to be developed for incorporating knowledge from a manufacturing plant. The knowledge from various shops have to be collected into a control unit, that would indicate the time delays of the complete assembly plant. The system should also indicate the remedies for reducing the time delays in the each shop of the plant such as paint shop, heat treatment shop etc. The system to be equipped with on-line modification facility for each shop.
TASK CHARACTERISTRICS !!!!!!!
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Problem Selection: Solution Problem Selection: Solution
Black Board
Diverse Source of knowledge from each shop
Cooperating Knowledge sources
Rule and Control
For each Shop
With Modification Facilities such as knowledge base editor
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Prototype ConstructionPrototype Construction
What should be the primary aim of Prototyping?
To learn more about the domain
To gain deeper understanding of the nature of the project
To demonstrate overall systems’ functionalities
To test the initial design
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Prototype ConstructionPrototype Construction
Should the prototype be kept for detailed design?
Keep only those parts of the prototype whose level of implementation quality is similar to that expected of the final system
If it has to be discarded that should only be done after guidelines are for new implementation are extracted from the experience
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
FormalisationFormalisation
Formalisation is the development proces
Record key understandings from the prototyping phase
Plan the implementation
Provide visibility at each level
Draw implementation plans
Revisit pre formalisation steps to improve
When formalisation is inevitable?.
For large scale systems the formalisation step becomes very important
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Formalisation: StepsFormalisation: Steps
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Implementation PlansImplementation Plans
Prototype revisited
System framework development
Core knowledge Acquisition
Coding
Internal Integration
Internal verification
Revision of inference engine and representation methods
Establishing and revising knowledge base partitioning
Further verification
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Core Knowledge DevelopmentCore Knowledge Development
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
EvaluationEvaluation
Gradual degradation Vs Sudden Collapse
Task difficulty Task difficulty
Ad
equ
acy
Ad
equ
acy
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Complete ExampleComplete Example
Want to develop an expert system for detecting fire and suggesting remedial action
Gather Initial Data
Fire occurs when the room temperature is high and smoke appears
Temperature can be measured using Temperature gauge
Smoke can be indicated using smoke detector
Remedial action could be to assert that fire is on and then to call the fire brigade/or switch on the sprinklers
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Complete ExampleComplete Example
Carry Out Task Characteristics
What should be the architecture of the knowledge representation?.
Black Board or Rule control based
Rule Based Control
Represent knowledge in appropriate manner
Tree format
Extract rules from the tree
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Tree FormatTree Format
Switch on the sprinklers
Fire
hotsmokyAlarm beeps
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
RulesRules
IF alarm beeps THEN smoky
IF hot AND smoky THEN fire
IF fire THEN switch on the sprinklers
Which rule should be fired?.
Depends on the state of the initial database of facts
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Rules Based SystemRules Based System
Need to assert the initial facts in a database and then to change them
after each rule is fired
Control Scheme
Database of factsalarm beeps
hot
RulesIF alarm beeps THEN ADD smokyIF hot AND smoky THEN ADD fireIF fire THEN ADD switch on the sprinklers
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Rules – Rules – Representation Using CLIPSRepresentation Using CLIPS
IF temperature(R,hot) AND environment(R,smoky) THEN fire-in(R)
(defrule fire-alarm
(temperature ?r1 hot)
(environment ?r1 smoky)
(assert (fire-in ?r1)))
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
ProblemProblem
A problem faced by an organisation is to select candidates from among a very large pool of individuals for appointment to advanced training. Since the cost incurred for such training is considerable it is deemed important to carry out this process in a logical, efficient manner. The selection is done in two phases. First a test is conducted followed by the second phase of physical examination and evaluation. People who perform good go straight to the second phase. After the 2nd phase the Outstanding candidates are approved while poor are reject and average are placed on the waiting list. The marginal candidates after the first phase are examined on the bases of their job performance. Good performers in this test are allowed for the second phase and rest are rejected.
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Decision TreeDecision Tree
Lahore University of Management Sciences, Lahore, Pakistan
Dr. M.M. Awais- Computer Science Department
Rule ExtractionRule Extraction