Range minimum query - A range minimum query, or RMQ, asks for the smallest value in a specified contiguous interval of an array.
Range query (database) - A range query retrieves database records whose values fall within specified boundaries.
Range restrictions - Range restrictions occur when the observations available for analysis cover only a limited part of the variation present in the population of interest.
Rank - The rank of a matrix is the number of linearly independent columns it contains, equivalently the number of linearly independent rows.
Rank (ordinality) - Rank, or ordinality, is the property of data that has a meaningful order but no meaningful spacing: first, second and third tell you who beats whom, not by...
Rank (Tensor) - Tensor rank, in TensorFlow and similar array-programming terminology, is the number of axes a tensor has.
Rank test - A rank test is a statistical test whose statistic uses the relative ordering of observations, or related ranked quantities, rather than relying directly on...
Ranked data - Ranked data are observations represented by their positions in an ordering rather than by their original numerical values.
Ranked retrieval - Ranked retrieval returns search results in an order intended to place the most useful or relevant items first.
Ranking - Ranking is the task of ordering items by relevance, preference or predicted value, so that the best option comes first, rather than assigning each item an...
Ranking Bias - Ranking bias is a tendency to treat highly ranked results as especially relevant or important partly because of their position.
Ranking loss - Ranking loss, in the multilabel evaluation sense used here, measures the fraction of relevant-versus-irrelevant label pairs that a model orders incorrectly...
Rankrandomization tests - Rank-randomization tests are nonparametric procedures that evaluate a statistic based on ranks against a distribution generated by permitted random...
Rao-Blackwellization - Rao - Blackwellization is a way to improve an estimator by replacing part of its random variation with an appropriate conditional expectation.
Rao-Blackwellized particle filter - A Rao-Blackwellized particle filter estimates a changing hidden state by sampling some variables while calculating the conditional distribution of others...
Rapidly exploring dense trees - Rapidly exploring dense trees, or RDTs, are incremental exploration structures that grow a tree through a configuration space using a dense sequence of...
Rapidly exploring random tree - A rapidly exploring random tree, or RRT, is a sampling-based planning structure that grows a branching tree through a state or configuration space.
Rare events - Rare events are outcomes with low probability or low frequency relative to a specified population, exposure or time horizon.
Rasch model - The Rasch model is a probabilistic measurement model relating a person's position on a latent trait to the difficulty of an item.
Rashomon effect in machine learning - The Rashomon effect in machine learning is the presence of multiple different models that predict the same data similarly well.
Rating scale - A Rating scale is a defined set of response options used to record a judgment about an item, experience, or characteristic.
Ratio estimation - Ratio estimation uses a relationship between a study variable and an auxiliary variable to estimate a population quantity.
Ratio scale - A ratio scale is a measurement scale with meaningful equal intervals and a meaningful zero, so ratios of values can represent ratios of the measured quantity.
Ratio test - The ratio test is a feature-matching rule that compares the distance to a descriptor's nearest candidate with the distance to its second-nearest candidate.
Rational agent - A rational agent is an agent that, given what it has perceived, chooses the action expected to achieve the best outcome according to its performance measure.
Rational quadratic kernel - The rational quadratic kernel is a covariance function that combines smooth relationships across a range of length scales.
Rational subgroups - Rational subgroups are deliberately formed groups of observations used in statistical process control so that within-subgroup variation represents a...
Rationality - In AI, rationality is the principle of choosing actions that maximize expected performance, given the agent's available evidence, prior knowledge, and...
Rauch-Tung-Striebel smoother - The Rauch-Tung-Striebel smoother is a backward-recursion algorithm that refines past state estimates using observations from an entire time interval.
RDBMS - RDBMS stands for relational database management system: software that manages a database organized around relations, commonly represented as tables.
RDF - RDF, the Resource Description Framework, is a data model for representing information as linked statements.
RDF triple - An RDF triple is a three-part statement consisting of a subject, predicate, and object.
Re-detection - Re-detection is the process of locating a previously tracked target again after tracking has failed, become uncertain or been interrupted.
Re-Pair - Re-Pair, short for recursive pairing, is a lossless grammar-based compression method that repeatedly replaces a frequent adjacent pair of symbols with a new...
Re-ranking - Re-ranking is a second pass that takes the shortlist produced by a fast first ranking and reorders it with a more expensive, more careful method before...
Reachable set - A reachable set is the collection of states a system can attain from specified initial conditions under the allowed transitions or inputs.
Reactive control - Reactive control chooses or adjusts actions in response to the current situation, using feedback from observations or an updated internal state.
Reactive layer - A reactive layer is the part of a robot or agent architecture that produces timely responses to current observations through relatively direct...
Reactive planning - Reactive planning organizes goal-directed behavior so that the next action depends on the situation encountered during execution.
Read noise - Read noise is random uncertainty introduced by the electronic process of measuring and reading a sensor's signal.
Read speech - Read speech is speech produced by reading a prepared text aloud. The wording is supplied in advance rather than composed entirely as the speaker talks.
Read - write conflict - A read - write conflict occurs when one transaction reads information that another transaction changes, creating an ordering dependency that matters to...
Real-time AI - Real-time AI is artificial intelligence designed to produce useful decisions or outputs within the timing requirements of its environment.
Real-time business intelligence - Real-time business intelligence is the use of frequently updated data and analysis to support business decisions while the information is still...
Real-time data - Real-time data is data made available soon enough after the underlying event or observation to support its intended immediate use.
Real-time dynamic programming - Real-time dynamic programming, or RTDP, is a method for improving decisions by updating value estimates along trajectories through a decision problem.
Real-Time Machine Learning - Real-time machine learning is the practice of making predictions on live data within tight time budgets, usually milliseconds to seconds, so the answer...