Glossary

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Fuzzy Logic(also: Fuzzy Inference)

Fuzzy logic is a form of many-valued logic that deals with approximate reasoning, where truth values range continuously between 0 and 1 rather than being strictly true or false. In assistive technology and signal processing, fuzzy logic systems are used to handle imprecise or…

GPS(also: Global Positioning System, GNSS, Satellite Navigation)

The Global Positioning System (GPS) is a satellite-based navigation system that provides location and time information to receivers on Earth. For accessibility, GPS is foundational to wayfinding apps used by blind and low-vision travelers, enabling turn-by-turn navigation and…

Gamification(also: Games with a Purpose, GWAP)

The application of game design elements — such as points, levels, leaderboards, and time challenges — to non-game tasks in order to increase engagement and motivation. In accessibility, gamification has been used to crowdsource tasks that are difficult to automate, such as…

Generative Adversarial Network(also: GAN, Adversarial Network)

A type of deep learning architecture consisting of two neural networks — a generator and a discriminator — that are trained in competition with each other. The generator creates synthetic data (such as images) while the discriminator tries to distinguish between real and…

Geocoding(also: Geo-coding, Geographic Coding)

The process of associating geographic coordinates (latitude and longitude) or location identifiers with objects, markers, or data points. In accessibility contexts, geocoding is used to tag physical locations with digital information that assistive technologies can use — for…

Haptic Technology(also: Haptics, Touch Technology)

Technology that creates tactile experiences through the application of forces, vibrations, or motions to the user, enabling interaction through the sense of touch. Haptic technologies range from simple vibration motors in smartphones to sophisticated force-feedback devices and…

Head-Mounted Display (HMD)(also: HMD, Head-Mounted Display, Smart Glasses)

A display device worn on the head that places visual content in front of one or both eyes. Head-mounted displays include AR smart glasses (like Vuzix Blade), VR headsets, and mixed reality devices. In accessibility applications, HMDs can present captions, sign language…

Home Automation(also: Domotics, Smart Home Automation)

The use of technology to automatically control household systems and appliances such as lighting, heating, ventilation, security, and entertainment. Home automation systems use sensors, timers, and programmable rules to operate devices without manual intervention. For people…

Huffman Coding(also: Huffman Algorithm, Huffman Tree)

A data compression algorithm that assigns shorter codes to more frequently occurring symbols and longer codes to less frequent ones, producing an optimal prefix-free encoding. In accessibility and AAC research, Huffman coding has been applied to the design of scanning interfaces…

Human Computation

A computing paradigm in which humans perform tasks that computers cannot yet do reliably, often embedded within systems that combine human and machine capabilities. The classic example is reCAPTCHA, which used human text recognition to digitise books while verifying users were…

HyDE(also: Hypothetical Document Embeddings)

A query-expansion technique for retrieval-augmented generation in which an LLM is first asked to generate a hypothetical answer to the user's question, and that hypothetical answer — rather than (or alongside) the raw query — is embedded and used to search the document index.…

Hybrid Space(also: Blended Space, Hybrid Community Space)

A community or program environment that combines both in-person and online elements, not necessarily simultaneously, to create a more accessible and inclusive experience. In accessibility contexts, hybrid spaces address barriers such as geographic distance, mobility limitations,…

ICT4D(also: Information and Communication Technologies for Development, ICTD)

A field of research and practice focused on how information and communication technologies can be designed, deployed, and used to support social and economic development, particularly in low- and middle-income countries. ICT4D examines the unique social, cultural, and…

IDE(also: Integrated Development Environment)

A software application that provides a comprehensive environment for writing, testing, and debugging code. Common IDEs include Visual Studio Code, IntelliJ IDEA, and Xcode. In accessibility contexts, IDEs are important because they can host plugins and extensions that help…

ISCII(also: Indian Script Code for Information Interchange)

A character encoding standard developed by the Government of India for representing Indian language text in digital systems. ISCII uses a single encoding scheme that can represent characters from all major Indian scripts by exploiting their common phonetic structure — each…

Image Processing(also: Digital Image Processing)

The use of computational algorithms to analyze, enhance, transform, or extract information from digital images. In accessibility, image processing techniques are applied to convert visual content into accessible formats for blind and visually impaired users, including generating…

Immersive Media(also: Immersive Content, Immersive Technology)

Digital content and technologies designed to create a sense of presence and embodiment by surrounding users with stimuli that engage multiple senses. This includes 360-degree video, virtual reality, augmented reality, and mixed reality experiences. Making immersive media…

Inertial Sensors(also: IMU, Inertial Measurement Unit)

Electronic sensors that measure motion and orientation, typically including accelerometers (measuring acceleration/tilt), gyroscopes (measuring rotation), and magnetometers (measuring magnetic field/compass heading). In accessibility applications, inertial sensors enable indoor…

Information Appliance(also: Smart Appliance, Dedicated Device)

A computing device designed for a specific, well-defined purpose that is communication-oriented and easy to use, in contrast to a general-purpose computer. Information appliances typically have reduced functionality and complexity compared to desktop or laptop computers, making…

Infrared(also: IR, Infrared Communication)

A wireless communication technology that uses infrared light to transmit data over short distances, commonly used in assistive technology for line-of-sight data exchange between devices. In accessibility applications, infrared transmission has been used in systems like Talking…

Instructional Technology(also: Educational Technology, EdTech)

Digital technologies intentionally designed and used for teaching and learning purposes, including learning management systems (Google Classroom, Canvas), educational software (Khan Academy, MyMathLab), student response systems (Kahoot), digital textbooks, and assessment…

Intelligent Personal Assistant(also: IPA, Virtual Assistant, AI Assistant)

A software agent that uses natural language processing and speech recognition to perform tasks, answer questions, and control devices on behalf of a user. Examples include Amazon Alexa, Google Assistant, Apple Siri, and Microsoft Cortana. While intelligent personal assistants…

Interactive Television(also: iTV, Interactive TV)

Interactive television (iTV) refers to television systems that allow viewers to interact with content beyond simply watching, through features such as voting on polls, accessing supplemental information, navigating menus, and using applications displayed on the TV screen. iTV…

Internet of Things(also: IoT)

A network of physical devices embedded with sensors, software, and connectivity that enables them to collect and exchange data over the internet. In accessibility contexts, IoT devices—including smart speakers, connected thermostats, automated locks, and wearable health…

Interoperability

The ability of different systems, devices, applications, or products to connect and communicate with each other in a coordinated way, without requiring special effort from the user. In accessibility, interoperability is critical because assistive technologies must be able to…

Key-Frame Animation(also: Keyframe Animation, Keyframing)

Key-frame animation is a technique in computer graphics where an animator defines specific poses or states (key frames) at particular points in time, and the computer automatically generates the intermediate frames (interpolation) to create smooth motion between them. In…

LLM(also: Large Language Model)

A large neural network trained on enormous volumes of text (and often code and images) to predict and generate natural language. Modern LLMs such as GPT-5, Claude, and Gemini can follow instructions, reason step-by-step, use tools, and — in multimodal variants — interpret images…

Landmark Extraction(also: Keypoint Detection, Skeletal Tracking)

A computer vision technique that identifies and tracks specific anatomical points (landmarks or keypoints) on the human body, hands, and face from images or video. In sign language technology, landmark extraction is a critical preprocessing step that converts raw video into…

Learning Management System(also: LMS)

A software platform used to create, deliver, manage, and track educational content and learning activities. Common examples include Blackboard, Moodle, Canvas, and Google Classroom. In the context of accessibility, LMS platforms are critical because they serve as the primary…

Linked Data(also: Linked Open Data, LOD)

A method of publishing structured data on the web so that it can be interlinked and queried across different sources using standard web technologies such as URIs and RDF (Resource Description Framework). In accessibility contexts, linked data has been proposed as a way to…

Linked Data(also: Linked Open Data, LOD)

A method of publishing structured data on the web so that it can be interlinked and queried across different sources using Semantic Web technologies such as RDF, URIs, and SPARQL. Linked Data principles enable disparate datasets — for example, transport accessibility information…

Localization(also: Position Estimation, Indoor Localization, User Localization)

Localization is the process of determining a user's position within an environment, typically using a combination of sensors such as GPS, inertial measurement units, BLE beacons, Wi-Fi signals, or computer vision. Accurate localization is the foundational challenge for all…

Location-Based Service(also: LBS, Location-Based Services)

A software application or platform that uses geographic position data — from GPS, Wi-Fi, Bluetooth beacons, or other localization technologies — to deliver context-aware information or functionality to users based on their physical location. In accessibility, location-based…

MIDI(also: Musical Instrument Digital Interface)

A technical standard for communication between electronic musical instruments, computers, and related audio devices. MIDI transmits digital messages representing musical events like note-on, note-off, velocity, and control changes rather than audio signals. Because MIDI data is…

MLLM(also: Multimodal LLM, Multimodal Large Language Model)

A large language model extended to accept and reason over multiple input modalities — typically images and text, and sometimes audio or video — in addition to producing natural-language output. Examples include OpenAI's GPT-4o, Anthropic's Claude, and Google's Gemini. In…

Machine Learning(also: ML)

A branch of artificial intelligence in which computer systems learn patterns from data to make predictions or decisions without being explicitly programmed for each scenario. In accessibility contexts, machine learning is used for a wide range of applications: predicting…

Math OCR(also: Mathematical OCR, Scientific Document Recognition)

Optical character recognition technology specifically designed to recognize and convert mathematical expressions, formulas, and scientific notation from printed or PDF documents into accessible digital formats such as LaTeX, MathML, or Microsoft Word. Standard OCR software…

Mobile Phone(also: Cell Phone, Cellular Phone, Mobile)

A mobile phone is a portable radio-telephone that connects to the public telephone network over cellular radio infrastructure. In digital-accessibility practice mobile phones are both an accessibility tool and an accessibility barrier: they are a primary delivery mechanism for…

Motion Tracking(also: Motion Capture, MoCap, Body Tracking)

Technology that records and analyses the movement of people or objects in real time, typically using cameras, sensors, or wearable devices to capture position, orientation, and velocity data. In accessibility applications, motion tracking enables systems to compare a user's body…

Music Information Retrieval(also: MIR)

An interdisciplinary field focused on extracting, analyzing, and organizing information from music data. Music information retrieval encompasses tasks like automatic transcription, genre classification, melody extraction, beat tracking, and music recommendation. For…

NFC Tag(also: Near Field Communication Tag, NFC)

An NFC (Near Field Communication) tag is a small, unpowered chip that can transmit data to a compatible smartphone or device when held within a few centimeters. In accessibility contexts, NFC tags are used in museums, galleries, and public spaces to provide on-demand information…

Off-the-Shelf Technology(also: OTS, Commercial Off-the-Shelf, COTS)

Commercially available products designed for the general consumer market without customization for specific user groups. In accessibility research, off-the-shelf technology refers to mainstream devices like smart speakers, thermostats, and lighting systems that were not designed…

Ontology(also: Web Ontology, Knowledge Ontology)

In computing and information science, a formal representation of knowledge within a domain, consisting of concepts, categories, properties, and the relationships between them. Ontologies enable machines to reason about and process domain knowledge in structured ways. In…

Open Data(also: Open Government Data, Public Data)

Data that is published and made freely available to everyone without copyright or patent restrictions, following the premise that transparency enables public accountability and innovation. In accessibility, open data initiatives publish information about the accessibility of…

OpenSCAD

An open-source, code-based 3-D computer-aided design (CAD) application that uses a scripting language to define 3-D models through constructive solid geometry operations. Unlike visual modeling tools, OpenSCAD creates models from textual descriptions of geometric primitives and…

OpenStreetMap(also: OSM)

A free, collaborative, open-source mapping project that provides geographic data including roads, buildings, and points of interest, contributed and maintained by volunteers worldwide. OpenStreetMap is significant for accessibility because its open data can be freely used to…

Optical Character Recognition (OCR)(also: OCR, Text Recognition)

Technology that converts images of text — such as scanned documents, photographs of signs, or PDF pages stored as images — into machine-readable text that can be processed by screen readers, search engines, and other software. OCR is a critical tool for making scanned documents…

Particle Filtering(also: Sequential Monte Carlo, Particle Filter)

Particle filtering is a probabilistic localization technique that estimates a user's position by maintaining a cloud of weighted "particles," each representing a possible location. As new sensor data arrives—from GPS, inertial sensors, or other sources—particles are updated,…

Particle filter(also: Sequential Monte Carlo, Monte Carlo localization)

A probabilistic algorithm that estimates a user's position by maintaining a set of weighted hypothetical locations (particles) and updating them based on sensor observations such as Bluetooth beacon signal strengths. In indoor navigation for people with visual impairments,…

Pedestrian dead reckoning(also: PDR, Inertial navigation, Step-and-heading)

A localization technique that estimates a person's position by counting their steps (to determine distance) and detecting turns (to determine heading changes) from a known starting point, using inertial sensors in a smartphone or wearable device. For blind indoor navigation,…