Artificial Intelligence - Glossary

Term	Simple meaning
A*	Search using cost paid plus estimated cost remaining
Activation function	Function converting a neuron's input into output
Actuator	Component through which an agent acts
Admissible heuristic	Estimate that never exceeds true remaining cost
Agent	System that perceives and acts in an environment
Alpha-beta pruning	Removes game-tree branches that cannot affect minimax
Backpropagation	Computes neural-network gradients from output toward input
Bayes' rule	Updates a hypothesis probability using evidence
Bayesian network	Directed acyclic graph of probabilistic dependencies
Bias	Adjustable constant added to a neuron's weighted sum
Breadth-first search	Expands the shallowest frontier node first
Conditional independence	Independence after another variable is known
Consistent heuristic	Heuristic obeying the triangle-style cost condition
Constraint satisfaction problem	Variables, domains, and constraints
Depth-first search	Expands the deepest frontier node first
Environment	External world in which an agent operates
Frame	Slot-value structure describing an object or situation
Gradient descent	Moves parameters opposite the loss gradient
Heuristic	Estimate used to guide search
Hidden Markov model	Temporal model with hidden states and observations
Knowledge graph	Network of entities and labelled relationships
Learning rate	Step size used during parameter updates
Loss function	Number measuring prediction error
Minimax	Chooses a move assuming an optimal opponent
Naive Bayes	Classifier assuming conditional feature independence
Ontology	Formal vocabulary of domain concepts and relationships
PEAS	Performance, Environment, Actuators, Sensors
Perceptron	Linear threshold learning unit
Rational agent	Agent choosing actions expected to maximize performance
Semantic network	Graph representation of concepts and relations
Sensor	Component through which an agent perceives
State space	Set of states reachable in a problem
Utility	Numerical preference for an outcome
Uniform-cost search	Expands the frontier node with lowest path cost