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Posit PBC
Posit PBC, formerly RStudio, is an American data science software company founded by J.J. Allaire in 2009, known for open-source tools like the RStudio IDE and Shiny.
Position encoding
Position encoding is the family of techniques a transformer uses to inject token order information, since self-attention alone treats input as an unordered set of vectors.
Position interpolation
Position interpolation is a 2023 technique from Meta for extending a language model's context window by linearly rescaling rotary position embeddings, extending LLaMA models to 32768 tokens.
Position-based dynamics
Position-based dynamics (PBD) is a physically based simulation method introduced by Matthias Müller and colleagues in 2007, widely used for real-time cloth, hair, and fluids in games.
Positional encoding
Positional encoding is a family of techniques that injects token order information into neural networks such as transformers, whose self-attention otherwise cannot distinguish sequence positions.
Positive bias temperature instability
Positive bias temperature instability (PBTI) is a reliability phenomenon in n-channel MOSFETs in which positive gate bias at elevated temperature causes electron trapping that shifts the threshold voltage.
Positive train control
Positive train control (PTC) is a communications-based rail safety system, mandated by the Rail Safety Improvement Act of 2008, that automatically slows or stops trains not operated safely.
Positive-unlabeled learning
Positive-unlabeled learning is a machine learning method that trains a binary classifier from only positive and unlabeled examples, used when negative data is unavailable or too costly to collect.
Positron AI
Positron AI is an American AI inference hardware startup founded in 2023 by former Lambda and Groq employees, selling the Atlas inference system and developing custom silicon called Asimov.
Positronic brain
A positronic brain is a fictional device invented by Isaac Asimov as the thinking organ of his robots, built around the Three Laws of Robotics.
Posiva
Posiva is a Finnish company, founded in 1995–1996 and owned by TVO and Fortum, building the world's first deep geological repository for spent nuclear fuel at Olkiluoto.
POSIX
POSIX, formally the Portable Operating System Interface and once proposed as IEEE-IX, is a family of IEEE standards defining a C API, shell, and utilities for application portability.
POSIX ACLs
POSIX ACLs are access control lists for files and directories that extend the traditional UNIX permission model with per-user and per-group entries, as in the withdrawn POSIX 1003.1e draft.
POSIX threads
POSIX threads, commonly called Pthreads, is the POSIX.1 standard interface for threaded programming in C, first standardized as IEEE Std 1003.1c-1995 and now part of POSIX.1-2024.
POSM process
The POSM process (propylene oxide/styrene monomer process), also called PO/SM or SMPO, co-produces propylene oxide and styrene monomer from ethylbenzene and propylene; it was commercialized in 1969.
Possibility theory
Possibility theory is a mathematical framework for reasoning under uncertainty from incomplete or imprecise information rather than randomness, introduced by Lotfi Zadeh in 1978 and developed by Dubois and Prade.
Possible reserves
Possible reserves are the most uncertain category of petroleum reserves, less likely to be recoverable than probable reserves, with at least a 10% recovery probability.
POST (HTTP)
POST is an HTTP request method that asks a server to process data sent in the request body, defined in RFC 9110 and used for forms and file uploads.
Post and lintel
Post and lintel, also called post and beam or trabeated, is a building system where upright posts carry horizontal lintels, the basis of Stonehenge and Greek temples.
Post and telecom unions of Africa and the Middle East
Post and telecom unions of Africa and the Middle East are trade unions representing postal, telegraph, and telecommunications workers, many formed during anti-colonial independence movements of the 1950s and 1960s.
Post en Telegraafdienst
Post en Telegraafdienst was the combined postal and telegraph administration of the Dutch East Indies, established by the colonial government in 1884 and remembered as the ancestor of Telkom Indonesia.
Post office
A post office is a retail and administrative facility of a national postal operator where the public can post letters and parcels and access services such as money orders and banking.
Post office box
A post office box, also known as a PO box, is a lockable compartment rented at a post office for receiving mail rather than home delivery.
Post Office Protocol
Post Office Protocol (POP) is an Internet protocol that lets an email client retrieve messages from a mail server, with POP3 defined in RFC 1939.
Post Office Research Station
The Post Office Research Station was the research center of the British General Post Office at Dollis Hill, London, where Tommy Flowers built the Colossus codebreaking computer.
Post-buckling analysis
Post-buckling analysis is a structural engineering method that traces a structure's equilibrium path beyond buckling, revealing limit loads and sensitivity to geometric imperfections in plates and shells.
Post-it note
Post-it note: 3M's small repositionable paper note with a low-tack acrylate microsphere adhesive, invented by Spencer Silver (1968) and Art Fry (1974), launched in the US April 6, 1980; iconic canary-yellow 3-inch pad held in MoMA's collection.
Post-mission disposal
Post-mission disposal (PMD) is the set of end-of-life actions that move spent spacecraft and rocket stages to reentry, graveyard orbits, or Earth escape, with rules like the FCC's 5-year deorbit requirement.
Post-occupancy evaluation
Post-occupancy evaluation (POE) is the systematic assessment of how an occupied building performs and how occupants experience it, typically run 12 to 18 months after handover to inform operations and future design.
Post-quantum cryptography
Post-quantum cryptography, also known as quantum-resistant cryptography, is cryptography designed to resist attacks from both classical and future quantum computers, replacing RSA and elliptic curve systems.