Artificial Intelligence - UNIT - 1 Topic : 2. AI_PROBLEMS

 

UNIT - 1

2. AI PROBLEMS


1. Introduction

AI problems refer to tasks or scenarios that require intelligence to solve—such as planning, reasoning, learning, decision-making, and perception. These problems can range from simple tasks (like playing tic-tac-toe) to complex ones (like autonomous driving or medical diagnosis).


2. Characteristics of AI Problems

Understanding the nature of AI problems helps in designing effective solutions.

a. Complexity

  • May involve large search spaces or huge amounts of data.
  • Problems may be computationally expensive (NP-hard).

b. Uncertainty

  • AI often works with incomplete, noisy, or ambiguous data.
  • Example: Speech recognition under background noise.

c. Dynamic Environment

  • The environment can change during problem-solving.
  • Example: Self-driving cars reacting to traffic.

d. Goal-Driven

  • AI problems typically involve achieving a defined goal or objective.
  • Example: Chess AI tries to win the game.

e. Real-Time Response

  • Some problems require decisions in real-time.
  • Example: AI in robotics or missile systems.

3. Types of AI Problems

AI problems can be broadly classified into the following categories:


3.1 Search Problems

These involve finding a path or solution from a start state to a goal state.

  • Examples:
    • Solving mazes
    • Pathfinding in maps
    • Puzzle-solving (e.g., 8-puzzle)
  • Techniques:
    • Breadth-First Search (BFS)
    • Depth-First Search (DFS)
    • A* Algorithm

3.2 Game Playing

AI is used to create agents that can play and often win in competitive games.

  • Examples:
    • Chess, Go, Checkers, Tic-tac-toe
  • Characteristics:
    • Adversarial (opponent involved)
    • Involves strategy and planning
  • Techniques:
    • Minimax algorithm
    • Alpha-Beta pruning

3.3 Planning Problems

Involves creating a sequence of actions to achieve a goal from a given initial state.

  • Examples:
    • Robot navigation
    • Task scheduling
  • Techniques:
    • STRIPS (Stanford Research Institute Problem Solver)
    • Partial Order Planning

3.4 Reasoning and Logic Problems

Require the system to infer new facts from known information using logic.

  • Examples:
    • Medical diagnosis
    • Legal reasoning
  • Techniques:
    • Propositional logic
    • Predicate logic
    • Inference rules

3.5 Natural Language Understanding (NLU)

AI systems understand and process human languages like English.

  • Examples:
    • Chatbots
    • Language translation
  • Challenges:
    • Ambiguity
    • Syntax and semantics
  • Techniques:
    • Parsing
    • Semantic analysis
    • NLP algorithms (e.g., transformers)

3.6 Perception and Robotics

Involves sensing and interpreting the physical world to interact meaningfully.

  • Examples:
    • Vision systems in autonomous vehicles
    • Robots detecting and grasping objects
  • Techniques:
    • Image processing
    • Computer vision
    • Sensor fusion

3.7 Learning Problems

Involve learning from data instead of being explicitly programmed.

  • Examples:
    • Spam email detection
    • Movie recommendation
  • Techniques:
    • Supervised Learning
    • Unsupervised Learning
    • Reinforcement Learning

4. Problem Formulation in AI

Before solving a problem, it must be formulated properly. This includes defining:

  • Initial state – Starting point
  • Actions – Possible operations
  • Transition model – Outcome of actions
  • Goal test – Whether the goal is achieved
  • Path cost – Measure of solution cost

A well-formulated problem helps AI algorithms work efficiently and effectively.


5. Example Problem: 8-Puzzle

Problem:

  • A 3x3 board with tiles numbered 1 to 8 and one blank.
  • The goal is to move the tiles to reach a specific goal configuration.

Formulation:

  • State: Current configuration of tiles
  • Actions: Move blank up/down/left/right
  • Goal Test: Matches goal configuration
  • Path Cost: Number of moves

Solution Methods:

  • BFS (for shortest path)
  • A* using heuristic like Manhattan Distance

 6. Real-Life AI Problem Examples

Problem

Domain

Solution Technique

Medical Diagnosis

Healthcare

Rule-based reasoning, ML

Speech Recognition

NLP

Neural Networks, HMM

Self-driving Cars

Robotics

Deep Learning, SLAM

Fraud Detection

Finance

Anomaly Detection, ML

Recommendation Systems

E-commerce

Collaborative Filtering


7. Common Challenges in AI Problem Solving

  • State-space explosion: Too many possible states
  • Ambiguity: Incomplete or unclear input
  • Uncertainty: Inaccurate or noisy data
  • Real-time constraints: Need fast decisions
  • Scalability: Problem grows with input size
  • Ethical issues: Fairness, bias, and misuse

8. Key Terms to Remember

  • State Space: Set of all possible states
  • Heuristic: Rule of thumb for guiding search
  • Agent: Entity that perceives and acts
  • Environment: External system where the agent operates
  • Goal State: Desired end condition

9. Summary

  • AI problems simulate real-world intelligent behavior.
  • They include search, logic, planning, language, perception, and learning.
  • Solving these problems requires proper formulation and appropriate techniques.
  • Challenges include uncertainty, complexity, and dynamic environments.

 

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