Glossary Terms

Telepresence is the sense of being physically present in a virtual environment rather than in one’s actual surroundings. Source: ACM Metaverse Glossary (Borg, Johansen, Thomsen & Kraus, 2012) Read more

Test data is data never shown to the algorithm during training, used afterwards to estimate how well the model performs. Keeping it strictly separate from training data is what makes that estimate meaningful. Sources: FDA Digital Health and AI Glossary; IMDRF N67 (2022) Read more

The metaverse is a network of interconnected virtual worlds characterized by presence, persistence, immersion, and interoperability. It is described as a collective shared space formed by the convergence of physical and digital reality, reachable from many kinds of device. Sources: XRSI Standard XR Definitions (XR-001); ACM Metaverse Glossary Read more

Training data is the data used to build an AI model, shaping its weights, connections, and components. It is held separate from the test data used to assess the finished model. Sources: FDA Digital Health and AI Glossary; IMDRF N67 (2022) Read more

Tuning data is used by the manufacturer of an AI system to evaluate a small number of trained models, typically to choose between them or adjust settings, before final testing. Source: FDA Digital Health and AI Glossary Read more

The uncanny valley is the discomfort people feel when a digital character approaches photorealism without quite achieving it. It is a common reason designers choose stylized rather than near-realistic human figures. Source: Unity Glossary Read more

Underfitting occurs when a model fails to capture the patterns and complexity of its training data, leading to poor performance on both the training data and new, unseen data. Source: FDA Digital Health and AI Glossary Read more

Unsupervised machine learning trains a model using only unlabeled data, finding structure within the data without being given correct answers. Sources: FDA Digital Health and AI Glossary; IMDRF N67 (2022) Read more

The vestibular system is the inner ear’s balance mechanism, which detects movement and orientation. A mismatch between what it senses and what the eyes see is the primary cause of simulation sickness in XR. Source: Unity Glossary Read more

Virtual collaboration lets geographically dispersed teams work together in real time within a shared digital environment, using synchronized object manipulation, spatial communication, and version control to keep work consistent. Source: Unity Glossary Read more