Artificial intelligence and data

Probability hypothesis density filter

The probability hypothesis density (PHD) filter is a recursive Bayesian algorithm for multi-target tracking, introduced by R.P.S. Mahler in 2003, that propagates the first-order moment of the multi-target posterior and avoids data association.

Probably approximately correct learning

Probably approximately correct (PAC) learning is a mathematical model of learning from examples, introduced by Leslie Valiant in 1984, requiring small error with high probability.

Procedural modeling

Procedural modeling is a computer graphics technique that generates 3D geometry, textures, and entire scenes algorithmically from rules and parameters, producing terrains, vegetation, roads, and cities for movies, games, and simulations.

Process mining

Process mining is a family of techniques that analyze event data recorded by information systems to discover, check, and improve business processes, using event logs recording cases, activities, and timestamps.

Processor sharing

Processor sharing is a queueing discipline in which a single server divides its capacity equally among all jobs present; introduced by Leonard Kleinrock in 1967, it models round-robin time sharing.

Producer–consumer problem

The producer–consumer problem, also called the bounded-buffer problem, is a classic concurrent programming problem in which producers fill a shared buffer that consumers drain, requiring synchronization.

Product quantization

Product quantization is a lossy vector compression method for approximate nearest-neighbor search that splits high-dimensional vectors into subvectors quantized separately, storing each as a short code from which distances are estimated.

Production system (computer science)

A production system is a rule-based artificial intelligence method in which condition-action rules, working memory, and an interpreter derive new facts, forming the basis of expert systems.

Program synthesis

Program synthesis is the task of automatically finding a program that satisfies a user's intent given as a specification, long called the holy grail of computer science.

Programming by demonstration

Programming by demonstration is a technique in which a system watches a user perform task examples and infers a generalized program or policy, rather than being programmed explicitly.

Oct 26, 2026

Project Nessie

Project Nessie (Nessie) is an open-source Apache-2.0 transactional Iceberg catalog for data lakes, originally open-sourced by Dremio, with Git-like branches, tags, and merges across tables, an Iceberg REST plus native API, and commits versioning the whole catalog.

Prometheus (software)

Prometheus is an open-source metrics monitoring and alerting system with a multidimensional time-series data model and the PromQL query language, started at SoundCloud in 2012 and now the default metrics layer for Kubernetes.

Pronunciation lexicon

A pronunciation lexicon maps words and short phrases to their pronunciations for speech recognition and text-to-speech engines; the best-known English one is the CMU Pronouncing Dictionary.

Proof complexity

Proof complexity is the study of the sizes of propositional proofs, asking whether every tautology has a short proof or some require exponential length; it began with Tseitin in 1966.

PropBank

PropBank (the Proposition Bank) is an English corpus annotated with predicate-argument structure, adding semantic role labels to the Penn Treebank's trees; it was created by Martha Palmer, Daniel Gildea, and Paul Kingsbury.

ProQuest

ProQuest, formerly University Microfilms International, is an American information company based in Ann Arbor, Michigan, founded in 1938 and known for dissertation databases and digitized newspapers.

Protection of Personal Information Act (South Africa)

The Protection of Personal Information Act, known as POPIA, is South Africa's omnibus data protection law, signed in 2013 and fully in force since 1 July 2021.

Protein Data Bank

The Protein Data Bank (PDB) is the open-access archive of experimentally determined 3D structures of proteins and other biological macromolecules, established in 1971 at Brookhaven National Laboratory.

Protein Information Resource

The Protein Information Resource (PIR) is a public bioinformatics resource that collects and annotates protein sequence information, established in 1984 and a founding partner of UniProt since 2002.

Prototypical network

A prototypical network is a metric-based few-shot learning method that classifies examples by comparing their embeddings to one prototype per class, introduced by Snell, Swersky, and Zemel at NIPS 2017.

Prototypical networks

Prototypical networks are a metric-based meta-learning method for few-shot classification, introduced by Jake Snell, Kevin Swersky, and Richard Zemel at NIPS 2017, which classifies queries by distance to class prototypes.

Proximal gradient method

The proximal gradient method, also known as proximal gradient methods, is a first-order algorithm minimizing smooth plus nonsmooth objectives, popularized as ISTA for l1-regularized problems.

Proximal point algorithm

The proximal point algorithm, or proximal point method, is an iterative optimization method that repeatedly minimizes a convex objective plus a quadratic penalty centered at the current iterate.

Pseudo-labeling

Pseudo-labeling is a semi-supervised learning technique in which a model treats its most confident predictions on unlabeled data as true labels, introduced for deep networks by Dong-Hyun Lee in 2013.

Pseudonymization

Pseudonymization is a data protection technique defined in Article 4(5) of the GDPR in which personal data is processed so it cannot be attributed to a person without separately protected additional information.

Pseudorandom number generator

A pseudorandom number generator (PRNG) is a deterministic algorithm that produces number sequences resembling randomness from a short seed, though outputs remain fully predictable if the seed is known.

PsyArXiv

PsyArXiv is a free, open-access preprint repository for the psychological sciences, created by the Society for the Improvement of Psychological Science and launched in 2016.

PsycINFO

PsycINFO, also called APA PsycInfo, is a bibliographic database of psychology and the behavioral sciences produced by the American Psychological Association, offered electronically since 1967.

PTAS

A PTAS, or polynomial-time approximation scheme, is a family of algorithms for NP-hard optimization problems that returns solutions within any chosen accuracy, for fixed accuracy running in polynomial time.