Correspondence problem - The correspondence problem is the challenge of determining which locations or features in different images refer to the same scene content.
Coscheduling - Coscheduling is the coordinated scheduling of related processes or threads so they can execute concurrently on different processors.
Cosine similarity - Cosine similarity measures the alignment of two nonzero numerical vectors by taking the cosine of the angle between them.
Cost efficiency - Cost efficiency describes how economically a process uses money to produce a defined useful result at the required quality and service level.
Cost Model - A cost model is a set of estimates and rules used to predict the resources or effort required by an operation.
Cost-sensitive machine learning - Cost-sensitive machine learning accounts for the fact that different prediction errors or actions can have different consequences.
Costmap - A costmap is a spatial representation that assigns navigation costs to locations.
Count data - Count data record how many events, objects, or observations occur within a defined unit, category, period, or amount of exposure.
Count nouns - Count nouns are nouns used to present their referents as distinct units that can be counted.
Count sketch - Count sketch is a compact probabilistic data structure for estimating item frequencies in a data stream.
Counterbalancing - Counterbalancing is the planned distribution of condition orders across participants or trials to reduce confounding between experimental conditions and...
Counterfactual explanation - A counterfactual explanation describes how an input could be changed so that a model would produce a different specified output.
Counterfactual fairness - Counterfactual fairness is a causal-model-based fairness criterion asking whether a prediction for an individual would remain the same in distribution under...
Countermeasure - A countermeasure is an action, mechanism or procedure intended to reduce a threat, vulnerability or harmful consequence.
Counternull - A counternull is a nonnull effect value that has the same evidential standing as a specified null value under a stated statistical procedure, commonly...
Counters - In the language context of this glossary, counters are counting expressions used with numerals to indicate the kind or unit of what is being counted.
Coupled hidden Markov model - A coupled hidden Markov model represents several interacting sequences of hidden states, with probabilistic dependencies connecting their evolution over time.
Coupled mixture model - A coupled mixture model is a set of mixture models trained together on related datasets, with links between their components so that evidence from one...
Coupled pattern learner - The Coupled Pattern Learner, or CPL, is a semi-supervised information-extraction method that learns text patterns for categories and relations together.
Coupling flow - A coupling flow is a normalizing flow built from invertible coupling transformations.
Covariance - Covariance measures how two variables vary together relative to their respective means.
Covariance function - A covariance function specifies the covariance between a random process's values at two inputs.
Covariance graph - A covariance graph is a graphical representation of marginal independence assumptions, commonly expressed through zeros in a Gaussian covariance matrix.
Covariance matrix - A covariance matrix is a square table describing the variances and pairwise covariances of a random vector's components.
Covariance matrix adaptation evolution strategy - Covariance matrix adaptation evolution strategy, or CMA-ES, is a randomized method for optimizing functions of continuous parameters without requiring their...
Covariant derivative (healing brush) - In the healing-brush context, a covariant derivative is a modified derivative that measures image variation relative to a chosen connection field.
Cover's theorem - Cover's theorem, in pattern recognition, concerns the capacity of linear decision surfaces to separate labeled points and how nonlinear feature...
Coverage bias - Coverage bias occurs when the population represented in a dataset does not adequately match the population about which conclusions or predictions are intended.
Coverage error - Coverage error is a measure of how far down a ranked list of labels a system must go to include every correct label for an example.
Cox model - The Cox model usually means Cox proportional hazards regression, a method relating predictors to the time until an event while accommodating appropriate...
Cramér's phi ( F c ) - Cramér's phi, commonly written phi_c and more widely known as Cramér's V, measures association between two categorical variables in a contingency table.
Crash blossom - A crash blossom is a headline or sentence whose wording invites a wildly wrong reading, named after a real headline about a musician whose career ended in a...
Criss-cross algorithm - The criss-cross algorithm is a family of pivot methods for linear programming that can start from a basis without requiring primal or dual feasibility.
Criterion validity - Criterion validity concerns how well a measurement relates to an appropriate external reference or outcome.
Criterion variable - A criterion variable is the variable a statistical model or prediction study aims to predict.
Critic - In reinforcement learning, the critic is the part of the system that judges how good the current situation or action is, while another part, the actor...
Critical path - A critical path is a sequence of dependent activities that determines a project's earliest completion time in a basic precedence schedule.
Critical path method - The critical path method, or CPM, is a scheduling technique that uses activity durations and dependencies to calculate early and late start and finish...
Critical value - A critical value is a boundary used in a statistical decision rule, commonly separating rejection and nonrejection regions for a hypothesis test.
Cromwell's rule - Cromwell's rule is advice to avoid assigning exact prior probabilities of zero or one to uncertain empirical propositions.
Cross-attention - Cross-attention is an attention mechanism in which queries come from one set of representations and keys and values come from another.
Cross-brackets - Cross-brackets, or crossing brackets, are a constituency-parser evaluation measure of incompatible phrase boundaries between a predicted parse and a...
Cross-correlation matrix - A cross-correlation matrix describes pairwise relationships between components of two random vectors.
Cross decomposition - Cross decomposition is a family of methods that finds hidden dimensions linking two sets of measurements, such as customer survey answers and purchase...
Cross-dissolve - A cross-dissolve is a transition that gradually reduces one image's contribution while increasing another's.
Cross-entropy - Cross-entropy is the expected negative logarithm of probabilities assigned by one distribution to outcomes generated by another.
Cross-entropy loss - Cross-entropy loss is a training objective that penalizes a model for assigning low probability to the correct outcome.