AI Rule-Based System - Virtual Lab

🎯 Aim

To design and implement a simple rule-based expert system that demonstrates forward-chaining inference mechanism for problem diagnosis.

Specific Objectives:

Understand the fundamental concepts of production systems and rule-based reasoning
Learn to represent domain knowledge using IF-THEN rules
Implement forward-chaining inference for automated decision making
Develop a working diagnostic system for real-world problem solving
Gain hands-on experience with knowledge representation and inference engines

📚 Theory: Rule-Based Systems

What is a Rule-Based System?

A rule-based system (or production system) is a type of artificial intelligence system that uses a set of if-then rules to represent knowledge and make decisions. It's one of the earliest forms of AI and is still widely used today.

Key Components:

Knowledge Base: Collection of rules (IF-THEN statements)
Working Memory: Current facts and data
Inference Engine: Applies rules to derive new facts
User Interface: Interaction with the system

Forward Chaining:

A reasoning method that starts with known facts and applies rules to derive new facts until a goal is reached. It's data-driven and works from facts to conclusions.

Example Rules for Light Diagnosis:

IF light_switch_on = False THEN cause = "Switch is off"
IF light_switch_on = True AND bulb_working = False THEN cause = "Bulb is fused"
IF light_switch_on = True AND bulb_working = True AND power_available = False THEN cause = "No power supply"

Step	Question Asked	Condition	Rule / Diagnosis
1	Is the switch ON?	`no`	Switch is off
2	Is the bulb OK?	`no` and switch is `yes`	Bulb is fused
3	Is there power?	`no` and above are `yes`	No electricity
4	All answers are `yes`		Problem with light fixture or wiring

🔬 Virtual Lab: Light Diagnosis System

Click 'Start Diagnosis' to begin the expert system!

🔍 Diagnosis Complete!

💻 Code

Rule-Based System Implementation

print("💡 Simple Light Diagnosis Expert System 💡")
print("Answer the questions to find out why the light is not working.\n")

# Step 1: Ask user if the switch is ON
switch = input("Is the switch ON? (yes/no): ")

if switch == "no":
    print("\n🔍 Diagnosis: The switch is OFF. Turn it ON.")
    print("Rule used: IF switch == 'no' THEN problem = switch is off")
    
else:
    # Step 2: Ask if the bulb is okay
    bulb = input("Is the bulb working (not fused)? (yes/no): ")
    
    if bulb == "no":
        print("\n🔍 Diagnosis: The bulb is fused. Replace it.")
        print("Rule used: IF switch == 'yes' AND bulb == 'no' THEN problem = bulb is fused")
    
    else:
        # Step 3: Ask if there's power
        power = input("Is there electricity/power? (yes/no): ")
        
        if power == "no":
            print("\n🔍 Diagnosis: No power supply. Check your electric board.")
            print("Rule used: IF switch == 'yes' AND bulb == 'yes' AND power == 'no' THEN problem = no power")
        
        else:
            # Step 4: All OK but still not working
            print("\n🔍 Diagnosis: There may be a wiring or fixture issue. Call an electrician.")
            print("Rule used: IF switch == 'yes' AND bulb == 'yes' AND power == 'yes' THEN problem = fixture issue")

print("\n✅ Done! You just used a Rule-Based System with IF-THEN logic.")