Glossary

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User Interface Agent(also: Interface Agent, Software Agent, Assistant Agent)

A software component that observes user behaviour and the state of an application, then unobtrusively offers help — suggestions, shortcuts, summaries, or warnings — to reduce workload or prevent errors. In accessibility research, interface agents have been used to monitor a…

User Modelling(also: User Modeling, User Profiling)

The process of creating and maintaining a digital representation of a user's characteristics, preferences, needs, and behaviours to personalise their interaction with a system. In accessibility contexts, user modelling captures information about a person's disabilities,…

User model(also: User modeling, User modelling)

A computational representation of a user's characteristics, abilities, preferences, and behavior patterns, used to predict how they will interact with a system or to adapt an interface to their needs. In accessibility contexts, user models capture attributes such as motor range…

User-System Model(also: User-System Interaction Model)

A conceptual model that describes the relationship between a user and the technology system they interact with, taking into account the user's abilities, preferences, and needs alongside the system's capabilities, interfaces, and constraints. In accessibility engineering,…

Value Sensitive Design(also: VSD)

A design methodology that accounts for human values in a principled and systematic way throughout the technology design process. Value Sensitive Design integrates three types of investigation: conceptual (identifying stakeholders and their values), empirical (studying how people…

Virtual reality(also: VR, Immersive virtual environment)

A computer-generated simulation of a three-dimensional environment that users can interact with using specialized hardware such as head-mounted displays and motion controllers. Virtual reality presents significant accessibility challenges because most VR applications rely…

Vision-based Page Segmentation(also: VIPS)

A web page segmentation algorithm that uses both the source code and the visual presentation of a web page to divide it into hierarchical visual blocks. VIPS produces a tree structure where the root node represents the entire page and leaf nodes represent the smallest meaningful…

Visual Attention Split(also: Split Attention, Divided Visual Attention)

The cognitive challenge of needing to divide visual focus between two or more sources of information simultaneously. For deaf and hard of hearing people, visual attention split is a pervasive accessibility barrier: they must look at captions or a sign language interpreter while…

Visual search

The perceptual task of scanning a visual scene to locate a specific target among distractors. Visual search is significantly affected by low vision, visual field loss, and other visual impairments, as reduced acuity or restricted fields make it harder and slower to locate…

Voice Assistant(also: Smart Speaker, Voice-Activated Assistant, Conversational Agent)

A software application that uses speech recognition and natural language processing to respond to voice commands and perform tasks. Common examples include Amazon Alexa, Google Assistant, and Apple Siri. Voice assistants offer accessibility benefits for users who have difficulty…

Voice Interaction(also: Voice User Interface, VUI, Voice-Based Interaction)

An interaction paradigm where users communicate with technology primarily through spoken commands and receive audio responses, rather than using visual displays, keyboards, or touch screens. Voice interaction combines speech-to-text for input, natural language processing for…

Voice-First Design(also: Voice-First Interface, Audio-First Design)

A design approach for applications and interfaces where voice is the primary input and output modality, with visual elements being secondary or absent. Voice-first design is particularly relevant for accessibility tools serving visually impaired users, where the entire user…

WIMP(also: Windows Icons Menus Pointer)

An acronym for Windows, Icons, Menus, and Pointers — the dominant graphical user interface paradigm used by most desktop operating systems since the 1980s. WIMP interfaces rely on a pointing device (typically a mouse) to interact with visual elements on screen, including…

Web Page Segmentation(also: Page Segmentation, Visual Page Segmentation)

The process of dividing a web page into its constituent visual blocks or semantic regions, such as headers, navigation menus, content areas, sidebars, and footers. Segmentation algorithms analyse both the source code (DOM structure) and the visual rendering of pages to identify…

Webcam-Based Interaction(also: Camera-Based Interaction, Video-Based Input)

An interaction paradigm where users communicate with a computer system through a webcam or camera, using gestures, sign language, facial expressions, or body movements as input. In accessibility contexts, webcam-based interaction enables alternative input methods for people who…

Wizard of Oz(also: WoZ, Wizard of Oz Testing, Wizard of Oz Prototyping)

A research and design method in which a human operator (the "wizard") secretly controls or simulates system responses that participants believe are automated. In accessibility research, Wizard of Oz studies allow researchers to test interaction concepts for assistive…

Wizard of Oz Study(also: WOZ Study, Wizard of Oz Method)

A research method in which participants interact with what they believe is an automated system, but which is actually operated in whole or in part by a human "wizard" hidden from view. The method is used to evaluate the usability and desirability of interfaces that do not yet…

Wizard-of-Oz(also: WOZ, Wizard of Oz Method, WOZ Study)

A research methodology where participants interact with what they believe is an autonomous system, but a human "wizard" is secretly operating it behind the scenes. Named after the 1939 film, this technique is commonly used in accessibility and HCI research to test interface…

Wizard-of-Oz Study(also: WOz Study, Wizard of Oz Method, WOz Technique)

A research methodology in human-computer interaction where participants believe they are interacting with an autonomous system, but a hidden human operator (the "wizard") is actually controlling some or all of the system's responses. This technique allows researchers to evaluate…

Wizard-of-Oz study(also: WoZ study, Wizard of Oz method)

A research methodology in which participants interact with a system they believe is automated, but which is actually operated partially or fully by a hidden human operator (the "wizard"). This approach allows researchers to evaluate user experience, interface design, and…

Workspace Awareness(also: Collaborator Awareness, Shared Workspace Awareness)

The up-to-the-moment understanding of another person's interactions within a shared workspace, including their location, actions, and intentions. In collaborative software development, workspace awareness encompasses knowing which file a colleague is viewing, what line they are…

Wrapping(also: Focus Wrapping, Cursor Wrapping)

An interface navigation technique where the focus or cursor automatically returns to the beginning of a line, list, or group of elements when it reaches the end, or vice versa. In accessible interfaces designed for low bandwidth input, wrapping reduces the number of signals…

Zipf's Law

A statistical observation that in any natural language corpus, the frequency of a word is inversely proportional to its rank in the frequency table. The most common word occurs roughly twice as often as the second most common, three times as often as the third, and so on. In…