Glossary
Searchable terminology from accessibility, web standards, and related fields.
110 results found in Human-Computer Interaction.
- Segmentation Problem (Stroke Segmentation, Input Segmentation, Gesture Segmentation)
- The segmentation problem in text entry and gesture recognition refers to the challenge of determining where one input unit (such as a letter, word, or gesture) ends and the next begins when there is n…
- Self-Adaptive System (Self-Adapting System, Adaptive Interface)
- A software or hardware system that automatically monitors user behaviour and adjusts its configuration or interface to better suit the user's needs without requiring explicit manual intervention. In a…
- Semiotic Inspection Method (SIM, MIS)
- An evaluation method from Semiotic Engineering theory that systematically assesses the communicability of an interactive system by examining how well the designer's intended message is conveyed throug…
- Shannon Entropy (Information Entropy, Source Entropy)
- A measure of the average uncertainty or unpredictability associated with a set of possible outcomes, defined by Claude Shannon as H = -Σ p(x) log₂ p(x), where p(x) is the probability of each outcome. …
- Simultaneous Assistance
- Simultaneous assistance, described by Cynthia Bennett and Daniela Rosner, is a form of support in which help flows in multiple directions at once rather than unidirectionally from a non-disabled helpe…
- Spatial Computing (Spatial interaction)
- A paradigm of computing in which digital content is rendered and interacted with in three-dimensional physical space, typically via head-worn augmented or mixed reality devices (e.g., HoloLens, Magic …
- Speech Acts Theory (Speech Act Theory, Illocutionary Acts)
- A theory from the philosophy of language, originally developed by J.L. Austin and John Searle, which holds that utterances are not just statements of fact but also actions that accomplish things — suc…
- Speech User Interface (SUI, Voice User Interface, VUI)
- A user interface that enables interaction with a computer or device primarily through spoken language rather than through physical input devices like keyboards, mice, or touchscreens. Speech user inte…
- Steering Law (Accot-Zhai Steering Law)
- A predictive model of human movement describing the time required to navigate a cursor through a constrained path, such as a tunnel or curved corridor on screen. Proposed by Accot and Zhai as an exten…
- Submovement (Movement Component, Movement Segment)
- A discrete component of a larger aimed movement, separated from other submovements by pauses or changes in velocity. According to the Optimized Submovement Model from motor performance theory, a rapid…
- Tablet Input (Graphics Tablet, Pen Tablet, Digitizer Tablet)
- An input device consisting of a flat surface that detects the position and movement of a stylus or digital pen, translating physical writing and drawing motions into digital input. Graphics tablets (s…
- Target Ambiguity (Command Ambiguity)
- A usability problem in voice and speech-based interfaces where a user's spoken command could refer to more than one element on the screen. For example, if multiple buttons share the same label in diff…
- Target Highlight Time (THT)
- A performance measure used in human-computer interaction research that captures the time elapsed between when a user positions a pointer over a target and when they initiate an action on that target, …
- Target Selection (Target Acquisition, Pointing)
- The fundamental interaction task of moving a cursor or pointer to a specific location on screen and confirming selection, such as clicking a button or link. Target selection difficulty is affected by …
- Task Analysis (Hierarchical Task Analysis, HTA)
- A systematic method for breaking down complex activities into their component tasks, subtasks, and actions to understand how users accomplish goals when interacting with a system. In accessibility and…
- Technology Probe
- A simple, flexible technology deployed in real-world settings to gather data about user needs, preferences, and interaction patterns. Unlike polished prototypes, technology probes are intentionally op…
- Time Diary (Time Use Diary, Activity Diary)
- A research methodology in which participants record their activities, experiences, or events in real time or near-real time as they occur, rather than recalling them retrospectively. In accessibility …
- Transfer Function (Mapping Function, Control-Display Gain)
- A mathematical function that defines the relationship between an input signal and an output response in a control system. In assistive technology and pointer control, a transfer function determines ho…
- Trimodal Feedback (Triple-Modality Feedback)
- A form of interface feedback that delivers information through three simultaneous sensory channels — typically auditory, haptic, and visual. Trimodal feedback offers the highest level of redundancy in…
- Usability Engineering
- A systematic, structured approach to designing and evaluating user interfaces that applies engineering principles to usability. Usability engineering involves defining measurable usability goals, cond…