Units function - A units function is a function used in a knowledge representation to connect a numerical value with a measurement unit and the quantity it denotes.
Univariate analysis - Univariate analysis examines one variable at a time to understand its values, distribution and other relevant properties.
Univariate design - A univariate design is an experimental design with one dependent variable or outcome.
Univariate feature selection - Univariate feature selection evaluates input features one at a time and selects those that score well under a chosen statistical criterion.
Universal approximation theorem - The universal approximation theorem refers to results showing that suitable neural-network families can approximate broad classes of functions as closely as...
Universal approximator theorem - The universal approximator theorem, more commonly called the universal approximation theorem, describes the expressive capacity of certain neural-network...
Universal code - A universal code, in this information-retrieval context, is an integer coding scheme with an efficiency guarantee across a specified class of source...
Universal code (data compression) - A universal code in data compression is a coding scheme designed to work across a specified class of sources without requiring the exact source...
Universal hashing - Universal hashing selects a hash function randomly from a family designed to limit collisions.
Universal Instantiation - Universal instantiation is an inference rule that applies a universally quantified statement to a particular term.
Universal IR Evaluation - Universal IR Evaluation refers here to a research approach for comparing information-retrieval outcomes through relationships among precision, recall...
Universal portfolio algorithm - The universal portfolio algorithm is an online portfolio-selection method introduced by Thomas Cover.
Universal psychometrics - Universal psychometrics is a research approach to measuring cognitive abilities across different kinds of systems, including humans, other animals...
Universal Relation Assumption - The universal relation assumption is a family of assumptions in relational database theory that treats the information of a database as describable through...
Universal Relation Schema - A universal relation schema is a conceptual relation schema containing all the attributes under consideration in a database-design problem.
Unknown Value - An unknown value is information that exists for the situation being described but is not known to the database or its users.
Unlabeled data - Unlabeled data is a collection of examples without known target answers for the learning task being considered.
Unlabeled example - An unlabeled example is one record containing input information without a known target answer for the task at hand.
Unlikelihood training - Unlikelihood training adds an objective that lowers the probability of selected undesirable outputs.
Unmatched count - Unmatched count refers to an indirect survey technique, also called the item count technique or list experiment, for estimating the prevalence of a...
Unnormalized form - Unnormalized form, often shortened to UNF, describes a data arrangement that has not been organized to meet first normal form in a conventional relational...
Unobserved heterogeneity in duration models - Unobserved heterogeneity in duration models means that units differ in their tendency to experience an event for reasons not captured by the observed...
Unrolling - Unrolling a dynamic Bayesian network means expanding its temporal template into an ordinary Bayesian network for a specified sequence of time steps.
Unscented Kalman filter - The unscented Kalman filter, or UKF, is a recursive state estimator that uses carefully selected sigma points to approximate how uncertainty passes through...
Unscented Kalman smoother - An unscented Kalman smoother estimates past hidden states using observations from an entire interval, applying sigma-point approximations to nonlinear state...
Unscented transform - The unscented transform is a deterministic method for approximating the mean and covariance of a random quantity after a nonlinear transformation.
Unsharp mask - An unsharp mask is a sharpening operation that compares an image with a blurred version and adds a scaled copy of their difference back to the original.
Unstructured data - Unstructured data is information whose substantive content is not organized into a predefined set of fields suitable for straightforward tabular analysis.
Unsupervised Biclustering - Unsupervised biclustering discovers related subsets of rows and columns in a data matrix without using target class labels to define those groups.
Unsupervised Clustering - Unsupervised clustering groups examples by patterns in their inputs without using predefined target labels to determine the groups.
Unsupervised learning - Unsupervised learning finds structure in data without using supplied target labels to guide the fitting objective.
Unsupervised parsing - Unsupervised parsing learns syntactic structure from sentences without using their reference parse trees as training targets.
Unsupervised Pretrained Network - An unsupervised pretrained network is a neural network whose parameters are first learned using an objective that does not require the eventual task's...
Unsupervised translation - Unsupervised translation is learning to translate between languages without externally supplied, paired bilingual training sentences.
Unsupported-claim rate - Unsupported-claim rate is the proportion of evaluated claims in a response that lack adequate grounding under a defined evidence standard.
Unvoiced sound - An unvoiced sound, also called a voiceless sound, is produced without the regular vocal-fold vibration that supplies voicing.
Up-and-down design - An up-and-down design is a sequential experimental design in which the level used for the next observation depends on the preceding response.
Update Anomalies - Update anomalies are problems that arise when a database's representation of facts makes changes difficult, inconsistent or unintentionally destructive.
Uplift modeling - Uplift modeling estimates how an intervention changes an outcome, often as a function of a person's or item's characteristics.
Upper confidence bound - An upper confidence bound is an upper limit intended to cover an unknown quantity with a specified confidence under stated assumptions.
Upper ontology - An upper ontology is a formal framework of very general categories and relationships intended to support more specialized descriptions across multiple domains.
Upweighting - Upweighting increases the contribution of selected examples to a calculation or learning objective.
URL normalization - URL normalization converts a web address into a consistent representation using rules that preserve its intended meaning.
Usability - Usability describes how well particular users can achieve their goals with a system in a particular setting, considering effectiveness, efficiency, and...
Usability testing - Usability testing evaluates a product by observing relevant users attempting realistic tasks with it.
Use And Interpretation Bias - Use and interpretation bias, in the supplied ontology's interpretive sense, is a systematic distortion in how ambiguous information, situations, or events...
User-centered design - User-centered design is an iterative approach to creating systems around an explicit understanding of the people who will use them, their goals, and their...
User-defined function - A user-defined function, or UDF, is a function supplied by a developer or user to perform a reusable operation beyond the system's existing built-in functions.