Ruled based expert system
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This document outlines the process of forward chaining and backward chaining using rules in an expert system to identify animals. It provides 15 rules relating animal characteristics to classifications like mammal, bird, carnivore, and ungulate. An example of forward chaining uses 5 facts and 3 rules to identify an animal as a giraffe. An example of backward chaining uses 6 facts, assumes the goal is cheetah, and applies 5 rules to verify this goal. The document demonstrates how forward and backward chaining can be applied in an expert system using if-then rules to identify unknown animals based on their characteristics.
Ruled based expert system
- 1. RULED-BASED EXPERT SYSTEM (FORWARD CHAINING AND BACKWARD CHAINING) -Amit Singh Dahal -g5638545
- 2. FIRST STEP: WRITE THE RULES BASED ON DIAGRAMS: R1: IF the animal has hair THEN it is a mammal R2: IF the animal gives milk THEN it is a mammal R3: IF the animal has feathers THEN it is a bird R4: IF the animal flies the animal lays eggs THEN it is a bird R5: IF the animal is a mammal the animal eats meat THEN it is a carnivore
- 3. CONTD… R6: IF the animal is a mammal the animal has pointed teeth the animal has claws the animal's eyes point forward THEN it is a carnivore R7: IF the animal is a mammal the animal has hooves THEN it is an ungulate R8: IF the animal is a mammal the animal chews cud THEN it is an ungulate AND it is even-toed
- 4. CONTD… R9: IF the animal is a carnivore the animal has a tawny colour the animal has dark spots THEN it is a cheetah R10: IF the animal is a carnivore the animal has a tawny colour the animal has black stripes THEN it is a tiger R11: IF the animal is an ungulate the animal has long legs the animal has a long neck the animal has dark spot THEN it is a giraffe R12: IF the animal is an ungulate the animal has a white colour the animal has black stripes THEN it is a zebra
- 5. CONTD… R13 :IF the animal is a bird the animal does not fly the animal has long legs the animal has a long neck the animal is black and white THEN it is an ostrich R14 :IF the animal is a bird the animal does not fly the animal swims the animal is black and white THEN it is a penguin R15 :IF the animal is a bird the animal is a good flier THEN it is an albatross
- 6. FORWARD CHAINING Facts in the working memory: -the animal gives milk -the animal chew cuds -the animal has long legs -the animal has a long neck -the animal has a dark spot Assume GOAL: the animal is Giraffe
- 7. Round 1: R2: IF the animal gives milk THEN it is a mammal fires mammal Round 2: R8: IF the animal is mammal the animal chews cud THEN it is an ungulate fires ungulate Round 3: R11: IF the animal is an ungulate the animal has long legs the animal has a long neck the animal has dark spot THEN it is a GIRAFFE Hence, goal reached. The used rules are: R2, R8 and R11.
- 8. BACKWARD CHAINING Facts in the working memory: -the animal has hair -the animal has claws -the animal has pointed teeth -the animal’s eyes point forward -the animal has a tawny color -the animal has dark spots Assume GOAL: the animal is Cheetah
- 9. Pass 1: Based on R10: ?the animal is carnivore the animal has a tawny color the animal has dark spot Stack: Cheetah R1 R1 AND
- 10. Pass 2: Based on R5 and R6: ?the animal is a mammal ?the animal can eat meat ?the animal is a mammal the animal has pointed teeth the animal has claws the animal eyes point forward Stack: AND AND OR R2 Carnivore R1 R2
- 11. Pass 3: Based on R1 and R2: the animal has hair the animal gives milk Stack: OR Mammal R1 R2
- 12. Pass 4: Based on R5 and R6: the animal is a mammal ? the animal can eat meat the animal is a mammal the animal has pointed teeth the animal has claws the animal eyes point forward Stack: AND OR AND Carnivore R1
- 13. Pass 5: the animal is carnivore the animal has a tawny color the animal has dark spot Stack: Clear Hence, goal is correct using backward chaining provided the information and the rules used are: R10, R5, R6, R1, R2. AND Cheetah