Clustering - Clustering is the task of grouping items by similarity so that items within a group are more alike than items in different groups, discovered from the data...
Clustering assumption - The clustering assumption is the idea, used in semi-supervised learning, that data points falling in the same natural cluster probably share the same label...
Clustering error - Clustering error is a measure of how wrong a clustering's group assignments are, usually counted as the smallest number of items that would need to move...
Clustering high-dimensional data - Clustering high-dimensional data means grouping records described by many features, often hundreds or thousands.
Clustering illusion - The clustering illusion is the tendency to see meaningful patterns or causes in clusters and streaks that can arise through chance.
Clutter - Clutter, in tracking and data association, means detections that do not come from the target or targets of interest and instead create nuisance observations.
CN2 algorithm - The CN2 algorithm is a rule-induction method that learns classification rules from labeled examples.
Co-adaptation - Co-adaptation is a failure mode in neural networks where individual units become useful only in the company of specific other units, making the network...
Co-domain - The co-domain of a function is the declared set in which its output values lie. If a function is written f:U→V, U is its domain and V is its co-domain.
co-NP - co-NP, usually written coNP, is the class of decision problems whose complementary problems belong to NP.
co-NP-complete - A decision problem is co-NP-complete, or coNP-complete, when it belongs to coNP and every problem in coNP can be transformed into it by a polynomial-time...
Co-occurrence matrix - A co-occurrence matrix counts how often pairs of values appear together under a specified relationship.
Co-occurrence network - A co-occurrence network represents items as nodes and connects items that appear together within a defined context.
Co-training - Co-training is a semi-supervised method where two models learn the same task from two different views of the data, each labeling examples it is confident...
Coalescence Rule - The coalescence rule is a database dependency inference rule that combines a multivalued dependency with a suitably related functional dependency to...
Coarse-to-fine - Coarse-to-fine is a strategy that begins with a simplified or lower-detail representation and progressively introduces more detail.
Coarse-to-fine alignment - Coarse-to-fine alignment is a method for matching images by estimating their displacement at a reduced resolution and then refining that estimate at...
Coarse-to-fine warping - Coarse-to-fine warping is a multiscale image-matching procedure that repeatedly transforms one image using a current motion estimate and then estimates the...
Cochran - Mantel - Haenszel statistics - Cochran - Mantel - Haenszel statistics are a family of methods for assessing association between categorical variables while accounting for specified strata.
Cochran's C test - Cochran's C test is an upper-tail variance-outlier test that examines whether the largest of several sample variances is unusually large relative to their...
Cochran's Q test - Cochran's Q test compares success probabilities across three or more related conditions when each response is binary.
Codd's 12 rules - Codd's 12 rules are criteria proposed by relational-database pioneer Edgar F.
Code-break procedure - A code-break procedure is a documented process for revealing a blinded trial participant's assigned intervention when authorized circumstances require it.
Code-excited linear prediction - Code-excited linear prediction, or CELP, is a speech-coding approach that represents speech using a predictive synthesis filter driven by a selected...
Code point - A code point is a numerical position in a coded character set. In Unicode, code points run from U+0000 to U+10FFFF.
Code switching - Code switching is the use of more than one language or language variety within a conversation, message or utterance.
Codebook - A codebook is a defined collection of representations identified by codes or indices.
Codec - A codec is a method or implementation for encoding and decoding a signal, commonly to store or transmit it efficiently.
Coded aperture - A coded aperture is a deliberately patterned opening or mask that changes how light reaches an imaging sensor.
Coding tree unit - A coding tree unit, or CTU, is a top-level picture-partitioning unit used in video coding, notably HEVC.
Coefficient matrix - A coefficient matrix is the rectangular array of numbers multiplying the variables in a system of linear equations.
Coefficient of determination - The coefficient of determination, usually written R², compares a regression model's squared prediction errors with the squared deviations of the observed...
Coefficient of multiple correlation - The coefficient of multiple correlation, usually written R, measures the strength of the linear relationship between one outcome and its best linear...
Coefficient of variation - The coefficient of variation, or CV, is the standard deviation divided by the mean.
Cognitive architectures - Cognitive architectures are general frameworks that specify how components such as memory, perception, reasoning, learning, and action selection work...
Cognitive automation - Cognitive automation is automation of work that involves interpreting varied information, such as reading documents, understanding requests or making...
Cognitive Bias - A cognitive bias is a systematic pattern in judgment or decision-making that can lead people away from an appropriate evaluation of evidence.
Cognitive computing - Cognitive computing is a broad term for computing approaches intended to support tasks associated with human cognition, such as interpreting language...
Cognitive map - A cognitive map is an internal representation of relationships in an environment that helps a person or animal orient, reason or plan.
Cognitive robotics - Cognitive robotics is the study and engineering of robots that connect perception, learning, reasoning and action to operate adaptively in their surroundings.
Cognitive science - Cognitive science is the interdisciplinary study of mind, cognition, and intelligent behavior.
Cohen's h - Cohen's h is an effect-size measure for the difference between two proportions after applying an arcsine-square-root transformation.
Cohen's kappa - Cohen's kappa is a statistic measuring agreement between two raters who assign categorical labels to the same items, adjusted for agreement expected under a...
Coherent extrapolated volition - Coherent extrapolated volition, or CEV, is a proposal in AI-alignment thinking that an advanced AI should be guided by what people would collectively want...
Cohort - A cohort is a group of people or other data units that share a defined characteristic or experience.
Cohort study - A cohort study follows a defined group of people or other units over time to observe outcomes, often comparing groups with different exposures or...
Cointegration - Cointegration is a relationship in which nonstationary time series share a linear combination that is stationary, under the relevant integration framework.