Knowledge-Based AI (KBAI)
An approach to AI that emphasizes explicit knowledge representations and reasoning methods to solve problems, often inspired by human cognition.
Cognitive System
A system that exhibits human-like intelligence through interacting processes such as learning, reasoning, and memory.
Cognitive System Components
Common components include input/output interfaces, reaction, deliberation, reasoning, learning, memory, and metacognition (monitoring/control).
Deliberation
A slower, goal-directed mode of processing that uses reasoning, learning, and memory to choose actions.
Reaction
A faster, stimulus-driven mode of processing that can produce quick responses without extensive deliberation.
Metacognition
The system’s ability to monitor and regulate its own thinking (e.g., detect impasses, choose strategies).
Fundamental Conundrum: Limited Resources
Intelligent agents have limited time, memory, and compute, so they must reason efficiently and strategically.
Fundamental Conundrum: Local Computation vs Global Constraints
Agents make local computations, but problems often have constraints that apply globally across the whole situation.
Fundamental Conundrum: Deduction vs Non-Deductive Problems
Logic is deductive, but many real problems involve uncertainty, incomplete data, or abductive/inductive reasoning.
Fundamental Conundrum: Dynamic World vs Limited Knowledge
The world changes, but the agent’s knowledge may be incomplete or outdated.
Explanation and Justification
Beyond solving problems, cognitive systems often need to explain and justify their reasoning and actions.
Intelligent systems must not only act intelligently
They must also be able to account for their decisions.
Knowledge Representation
How an agent encodes information so it can be used for reasoning and decision-making (e.g., graphs, rules, frames).
Represent and Reason
A general strategy: represent a problem in a structured form, then perform reasoning operations over that representation.
Different representations enable diff. reasoning strategies.
Semantic Network
A graph-based knowledge representation with nodes (concepts/objects) and labeled, directed links (relations).
Nodes (Semantic Networks)
The entities/concepts in a semantic network (e.g., ‘Bird’, ‘Eagle’, ‘Block’).
Links (Semantic Networks)
Directed, labeled relations between nodes (e.g., is-a, part-of, supports, left-of).
Good Representations
Make relationships explicit, expose constraints, combine objects with relations, exclude irrelevant detail, and remain computable.
State Space
A set of possible configurations (states) of a problem and the transitions (operators) between them.
Operator
An action that moves from one state to another in a state space (e.g., Move(C, Table) in blocks world).
Generate and Test
A problem-solving method that generates candidate solutions and tests them until one passes.
Generator (Generate and Test)
The component that proposes candidate solutions (can be naive or ‘smart’).
Tester (Generate and Test)
The component that evaluates candidates against constraints or goals (can be naive or ‘smart’).
Smart Tester
A tester that detects failure early or uses structure to prune candidates, reducing search.
Smart Generator
A generator that uses domain knowledge/constraints to generate better candidates and avoid obviously bad ones.