Technology and the built world

Hyperdimensional computing

Hyperdimensional computing (HDC), also known as vector symbolic architectures, is a family of computational models that represent data as very high-dimensional hypervectors, coined by Pentti Kanerva in 2009.

Hyperelastic model

A hyperelastic model is a constitutive law for rubber-like materials in which stress derives from a strain energy density function, making work path independent; named forms include Mooney-Rivlin, Ogden, and Gent.

Oct 22, 2026

Hyperfluorescence

Hyperfluorescence is an OLED mechanism in which a TADF sensitizer transfers excitons to a narrowband fluorescent emitter, considered the fourth generation of OLED emitter technology.

Hypergolic propellant

A hypergolic propellant, also called hypergolic fuel, is a rocket propellant combination whose fuel and oxidizer ignite spontaneously on contact, typically monomethylhydrazine and dinitrogen tetroxide, making engines reliable and storable for years in spacecraft.

Hypergraph convolutional network

A hypergraph convolutional network (HGNN) is a neural network that generalizes graph convolution to hyperedges linking many vertices, introduced by Yifan Feng in 2018 and published at AAAI 2019.

Hypergraph learning

Hypergraph learning is machine learning on hypergraphs, whose hyperedges connect any number of nodes to model higher-order interactions like co-authorship, with deep-learning methods now predominant.

Hypergraph neural network

A hypergraph neural network (HNN or HGNN) is a graph neural network that operates on hypergraphs, where one hyperedge connects any number of nodes, serving node classification and recommendation.

Hyperion Data Center

Hyperion Data Center is a Meta artificial intelligence data center campus in Richland Parish, Louisiana, announced in 2024 at $10 billion and expanded in 2026 to more than $50 billion.

Hyperlink

A hyperlink, also known as a web link, is a connection between two resources on the web, realized by embedding a URL in one page that points to another.

HyperLogLog

HyperLogLog (HLL) is a probabilistic algorithm introduced in 2007 by Philippe Flajolet and colleagues that estimates the number of distinct elements in a data stream using fixed, small memory, trading a small error for space.

Hyperloop

Hyperloop is a proposed transport mode in which pods travel through low-pressure tubes at up to 1,200 km/h, first outlined by Elon Musk in 2013.

Hyperloop Transportation Technologies

Hyperloop Transportation Technologies, known as HyperloopTT, is an American-founded company developing the hyperloop, which moves people and goods in levitating capsules through low-pressure tubes at airplane speeds.

Hypermedia

Hypermedia is multimedia content, including text, images, audio, and video, connected by links users follow; Ted Nelson coined the term in 1965, and the World Wide Web realizes it.

HyperNEAT

HyperNEAT is an indirect encoding method for evolving artificial neural networks, in which a CPPN generates connection weights from node coordinates; it extends NEAT and was introduced in 2009.

Hypernetworks

A hypernetwork (hypernet) is a neural network that generates the weights of another network, the target, introduced by David Ha, Andrew Dai, and Quoc V. Le in 2016.

Hyperoxia

Hyperoxia is the exposure of body tissues to oxygen at a higher than normal partial pressure, which can cause oxygen toxicity affecting the nervous system and lungs.

Hyperparameter (machine learning)

A hyperparameter in machine learning is a configuration value, such as the learning rate or number of layers, set before training rather than learned from the data.

Hyperparameter optimization

Hyperparameter optimization, also called hyperparameter tuning, is the process of searching for machine learning settings, like learning rate or network size, that give the best performance, usually judged by cross-validation.

Hyperparameter search

Hyperparameter search is a machine learning method that automatically tunes a model's hyperparameters, such as learning rate or regularization strength, by evaluating candidate configurations and selecting those that optimize validation performance.

Hyperscaler AI capital expenditure

Hyperscaler AI capital expenditure is the data center, chip, and power spending of Microsoft, Amazon, Alphabet, Meta, and Oracle, which has grown almost fivefold since ChatGPT's 2022 launch.

Hypersonic flight

Hypersonic flight is flight through an atmosphere at speeds above Mach 5, where aerodynamic heating dominates design; NASA has studied it since the 1950s X-15.

Hypersonic inflatable aerodynamic decelerator

A hypersonic inflatable aerodynamic decelerator (HIAD) is a deployable aeroshell that acts as both heat shield and drag device, packing small and inflating larger than any rocket fairing.

Hypersonic speed

Hypersonic speed, also called hypersonic velocity, is flight through an atmosphere above Mach 5, where aerodynamic heating rather than lift or drag dominates the physics.

Hypersonic weapon

A hypersonic weapon, also known as a hypersonic missile, is a maneuvering missile that flies at Mach 5 or faster within the atmosphere, as glide vehicles or scramjet-powered cruise missiles.

Oct 22, 2026

Hyperspectral photoluminescence imaging

Hyperspectral photoluminescence imaging is a non-destructive optical technique that records a full luminescence spectrum at every pixel, used to map defects and local voltage in solar cells.

HyperStrong

HyperStrong (Beijing HyperStrong Technology, 海博思创) is a Chinese battery energy storage integrator founded in 2011, with over 400 projects, 70 GWh deployed, and a 2025 STAR Market listing.

HyperTalk

HyperTalk is the English-like scripting language of HyperCard, Apple's hypermedia program for the Macintosh first released in 1987; Dan Winkler implemented the language, which Bill Atkinson's program inspired.

Hypertext

Hypertext is computer text with links letting readers choose their own path, a term coined by Ted Nelson in 1963 that underlies the World Wide Web.

HyperTransport

HyperTransport (HT) is a bidirectional, packet-based chip interconnect standard developed by AMD and standardized by a consortium from 2001, used in Opteron systems and supercomputers.