PDE-constrained optimization - PDE-constrained optimization chooses the best design, control or parameter values while requiring a system to obey specified partial differential equations.
PDE / diffusion inpainting (Bertalmío) - PDE-based inpainting fills a selected missing or damaged image region using equations that propagate information from its surroundings.
Peak signal-to-noise ratio (PSNR) - Peak signal-to-noise ratio, or PSNR, is a logarithmic measure comparing the allowed peak signal range with the mean squared error between a test image and a...
Pearson correlation coefficient - The Pearson correlation coefficient measures the direction and strength of linear association between two quantitative variables.
Pearson's chi-square ( c 2 ) - Pearson's chi-square is a statistic that compares observed counts with counts expected under a specified null hypothesis.
PEAS - PEAS is a framework for describing an intelligent agent's task environment.
Pedagogical agent - A pedagogical agent is a software-based character or interactive assistant designed to support learning.
Peeking - Peeking, in machine-learning evaluation, means using information from a test set to influence model development or selection and then treating performance...
Penalty method - A penalty method tackles constrained optimization by adding a cost for violating constraints to the objective being minimized.
Penalty term - A penalty term is an additional part of an optimization objective that makes specified properties or behaviors less attractive.
Per-comparison error rate - The per-comparison error rate is the Type I error probability associated with an individual hypothesis test: rejecting that test's null hypothesis when it...
Per-word entropy - Per-word entropy expresses uncertainty in a word-generating process on an average-per-word basis.
Perceiver - Perceiver is a neural-network architecture that uses cross-attention to map a large input into a smaller latent array, then performs most processing within...
Percentage of agreement - Percentage of agreement is the percentage of comparable observations for which two or more assessments match, under an explicitly stated agreement rule.
Percentile - A percentile is a value marking a specified cumulative position in a distribution. The 75th percentile, for example, corresponds to cumulative probability 0.75.
Percentile Bootstrap Confidence Interval - A percentile bootstrap confidence interval estimates uncertainty by repeatedly resampling the observed data, recalculating a statistic and taking specified...
Percept - A percept is the input an agent receives from its sensors at a particular observation step.
Percept schema - A percept schema, in AI planning, is a structured description of what an agent can observe and under which conditions that observation becomes available.
Percept sequence - A percept sequence is the ordered history of observations an agent has received up to a particular point.
Perception - Perception is the process by which an AI system interprets sensory observations to form useful representations of objects, events or conditions.
Perception - distortion tradeoff - The perception - distortion tradeoff describes a tension in image reconstruction between matching an individual reference image according to a distortion...
Perceptron - A perceptron is a simple linear classification model that combines numerical inputs with weights and a bias, then applies a threshold to choose a class.
Perceptron learning rule - The perceptron learning rule is an error-driven procedure for adjusting a linear classifier's weights and bias.
Perceptual computing - Perceptual computing, in the computing-with-words tradition, is an approach to supporting subjective judgments by representing linguistic assessments...
Perceptual robotics - Perceptual robotics studies how principles of perception can inform the design of robots and their interaction with the world.
Perfect Graph - A perfect graph is a finite simple undirected graph in which every induced subgraph can be colored using exactly as many colors as the size of its largest...
Perfect hash function - A perfect hash function maps every distinct key in a specified set to a different hash value, with no collisions within that set.
Perfect information - Perfect information is a property of a sequential game in which the player making a decision knows the history of play up to that point.
Perfect rationality - Perfect rationality is the ideal of always selecting an action that maximizes expected performance, given the information available to the agent and its...
Performance element - The performance element is the part of a learning agent that selects actions in response to its available observations and internal state.
Performance measure - A performance measure is the criterion used to evaluate how well an agent achieves the intended task.
Period disambiguation - Period disambiguation is the task of deciding what a period character does in its particular context, especially whether it marks the end of a sentence.
Periodic kernel - A periodic kernel is a covariance function that represents repeating relationships in a Gaussian process or another suitable kernel model.
Permutation language modeling - Permutation language modeling trains an autoregressive model using different orders for predicting token positions.
Permutation test - A permutation test assesses a statistic by comparing its observed value with values produced by rearrangements allowed under a null hypothesis or an...
Permutation variable importances - Permutation variable importances measure how much a fitted model's performance changes when the values of an input variable are shuffled across evaluation...
Permutational analysis of variance - Permutational analysis of variance commonly refers to PERMANOVA, or permutational multivariate analysis of variance.
Permutations - Permutations are ordered arrangements of objects.
Permuterm index - A permuterm index is a vocabulary index that supports wildcard matching by storing cyclic rotations of each term with a special end marker.
Perpetual punishment - Perpetual punishment is a repeated-game strategy feature in which a detected deviation triggers a punishment phase that continues for every remaining round.
Perplexity - Perplexity measures how well a probabilistic model predicts an observed sequence, commonly a sequence of words or tokens.
Persistence arc - A persistence arc is a directed connection from a variable at one time step to its copy at a later step in a dynamic Bayesian network.
Persistence barcode - A persistence barcode is a collection of intervals that records when topological features appear and disappear as a parameter changes.
Persistence module - A persistence module is an indexed family of algebraic objects together with maps that describe how information passes from one index to later indices.
Persistent Betti number - A persistent Betti number counts the independent homology classes present at an earlier filtration parameter that remain nonzero and independent at a later...
Persistent contrastive divergence - Persistent contrastive divergence, or PCD, is a learning method for energy-based models that maintains sampling chains across parameter updates.
Persistent failure model - A persistent failure model represents a fault as a state that continues across time, rather than treating each faulty observation as an unrelated accident.