Terms beginning with a capital letter have the meaning defined in Table 1. Terms beginning with a small letter have the meaning commonly defined for the context in which they are used. For instance, Table 1 defines Object and Scene but does not define object and scene.

A dash “-” preceding a Term in Table 1 indicates the following readings according to the font:

  1. Normal font: the Term in the table without a dash and preceding the one with a dash should be read before that Term. For example, “Avatar” and “- Model” will yield “Avatar Model.”
  2. Italic font: the Term in Table 1 without a dash and preceding the one with a dash should be read after that Term. For example, “Avatar” and “- Portable” will yield “Portable Avatar.”

Table 1Table of terms and definitions

Term Definition
Attitude
–       Social The coded representation of the internal state related to the way a human or avatar intends to position vis-à-vis the Environment or subsets of it, e.g., “Respectful”, “Confrontational”, “Soothing”.
–       Spatial Position and Orientation and their velocities and accelerations of an Audio and Visual Object in a Virtual Environment.
Audio Digital representation of an analogue audio signal sampled at a frequency between 8-192 kHz with a number of bits/sample between 8 and 32, and non-linear and linear quantisation.
–       Object Coded representation of Audio information with its metadata. An Audio Object can be a combination of Audio Objects.
–       Scene The Audio Objects of an Environment with Object location metadata.
Audio-Visual Object Coded representation of Audio-Visual information with its metadata. An Audio-Visual Object can be a combination of Audio-Visual Objects.
Audio-Visual Scene (AV Scene) The Audio-Visual Objects of an Environment with Object location metadata.
Avatar An animated 3D object representing a real or fictitious person in a Virtual Space.
–       Model An inanimate avatar exposing interfaces enabling animation.
Cognitive State The coded representation of the internal state reflecting the way a human or avatar understands the Environment, such as “Confused”, “Dubious”, “Convinced”.
Colour (of speech) The timber of an identifiable voice independent of a current Personal Status and language.
Connected Autonomous Vehicle A vehicle able to autonomously reach an assigned geographical position by:

1.     Understanding human utterances.

2.     Planning a route.

3.     Sensing and interpreting the Environment.

4.     Exchanging information with other CAV.

5.     Acting on the CAV’s motion actuation subsystem.

Context Additional information about a communication emitted by an Entity, such as language, culture etc..
Data Information in digital form.
–       Format The standard digital representation of Data.
–       Type An instance of Data with a specific Data Format.
Descriptor Coded representation of text, audio, speech, or visual feature.
Digital Representation Data corresponding to and representing a real entity.
Emotion The coded representation of the internal state resulting from the interaction of a human or avatar with the Environment or subsets of it, such as “Angry”, “Sad”, “Determined”.
Entity A real or Digital Human
Environment A Virtual Space containing a Scene.
Face The portion of a 2D or 3D digital representation corresponding to the face of a human.
Factor One of Emotion, Cognitive State and Attitude.
Gesture A movement of the body or part of it, such as the head, arm, hand, and finger, often a complement to a vocal utterance.
Grade The intensity of a Factor.
Human A human being in a real space.
–       Digital A Digitised or a Virtual Human in a Virtual Space.
–       Digitised An Object in a Virtual Space that has the appearance of a specific human when rendered.
–       Virtual An Object in a Virtual Space created by a computer that has a human appearance when rendered but is not a Digitised Human.
Identifier The label uniquely associated with a human or an avatar or an object.
Instance An element of a set of entities – Objects, users etc. – belonging to some levels in a hierarchical classification (taxonomy).
Intention The result of analysis of the goal of an input question.
Manifestation The manner of showing the Personal Status, or a subset of it, in any one of Speech, Face, and Gesture.
Meaning Information extracted from Text such as syntactic and semantic information, Personal Status, and other information, such as an Object Identifier.
Modality One of Text, Speech, Face, or Gesture.
Object Descriptors Attribute of the coded representation of an object in a Scene, including its Spatial Attitude.
Orientation The set of the 3 roll, pitch, yaw angles indicating the rotation around the principal axis (x) of an Object, its y axis having an angle of 90˚ counterclockwise (right-to-left) with the x axis and its z axis pointing up toward the viewer.
Personal Status The ensemble of information internal to a person, including Emotion, Cognitive State, and Attitude.
Portable Avatar A Data Type representing an Avatar and its Context.
Pitch The fundamental frequency of Speech. Pitch is the attribute that makes it possible to judge sounds as “higher” and “lower.”
Point of View The Spatial Attitude of a human or avatar looking at an Environment.
Position The 3 coordinates (x,y,z) of a representative point of an object in the Real and Virtual Space.
Refined Text The Text resulting from the analysis of the Text produced by Automatic Speech Recognition made by Natural Language Understanding.
Scene A structured composition of Objects.
Speech Digital representation of analogue speech sampled at a frequency between 8 kHz and 96 kHz with a number of bits/sample of 8, 16 and 24, and non-linear and linear quantisation.
–       Features Aspects of a speech segment that enable its description and reproduction, e.g., degree of vocal tension, Pitch, etc., and that can be automatically recognised and extracted for speech synthesis or other related purposes.
–       Rate The number of Speech Units per second.
–       Unit Phoneme, syllable, or word as a segment of Speech.
Summary An abridged outline of the content of the utterance(s) of one or more Users possibly including their Personal Statuses.
Text A sequence of characters drawn from a finite alphabet.
Visual Object Coded representation of Visual information with its metadata. A Video Object can be a combination of Video Objects.
Vocal Gesture Utterance, such as cough, laugh, hesitation, etc. Lexical elements are excluded.

Table 2 – MPAI-wide Terms

Term Definition
Access Static or slowly changing data that are required by an application such as domain knowledge data, data models, etc.
AI Framework (AIF) The environment where AIWs are executed.
AI Model (AIM) A data processing element receiving AIM-specific Inputs and producing AIM-specific Outputs according to according to its Function. An AIM may be an aggregation of AIMs.
AI Workflow (AIW) A structured aggregation of AIMs implementing a Use Case receiving AIW-specific inputs and producing AIW-specific outputs according to the AIW Function.
Application Standard An MPAI Standard designed to enable a particular application domain.
Channel A connection between an output port of an AIM and an input port of an AIM. The term “connection” is also used as synonymous.
Communication The infrastructure that implements message passing between AIMs.
Component One of the 7 AIF elements: Access, Communication, Controller, Internal Storage, Global Storage, Store, and User Agent
Composite AIM An AIM aggregating more than one AIM.
Component One of the 7 AIF elements: Access, Communication, Controller, Internal Storage, Global Storage, Store, and User Agent
Conformance The attribute of an Implementation of being a correct technical Implem­entation of a Technical Specification.
–       Testing The normative document specifying the Means to Test the Conformance of an Implem­entation.
–       Testing Means Procedures, tools, data sets and/or data set characteristics to Test the Conformance of an Implem­en­tation.
Connection A channel connecting an output port of an AIM and an input port of an AIM.
Controller A Component that manages and controls the AIMs in the AIF, so that they execute in the correct order and at the time when they are needed
Data Information in digital form.
–       Format The standard digital representation of Data.
–       Type An instance of Data with a specific Data Format.
–       Semantics The meaning of Data.
Descriptor Coded representation of a text, audio, speech, or visual feature.
Digital Representation Data corresponding to and representing a physical entity.
Ecosystem The ensemble of actors making it possible for a User to execute an application composed of an AIF, one or more AIWs, each with one or more AIMs potentially sourced from independent implementers.
Explainability The ability to trace the output of an Implementation back to the inputs that have produced it.
Fairness The attribute of an Implementation whose extent of applicability can be assessed by making the training set and/or network open to testing for bias and unanticipated results.
Function The operations effected by an AIW or an AIM on input data.
Global Storage A Component to store data shared by AIMs.
AIM/AIW Storage A Component to store data of the individual AIMs.
Identifier A name that uniquely identifies an Implementation.
Implementation 1.     An embodiment of the MPAI-AIF Technical Specification, or

2.     An AIW or AIM of a particular Level (1-2-3) conforming with a Use Case of an MPAI Application Standard.

Implementer A legal entity implementing MPAI Technical Specifications.
ImplementerID (IID) A unique name assigned by the ImplementerID Registration Authority to an Implementer.
ImplementerID Registration Authority (IIDRA) The entity appointed by MPAI to assign ImplementerID’s to Implementers.
Instance ID Instance of a class of Objects and the Group of Objects the Instance belongs to.
Interoperability The ability to functionally replace an AIM with another AIW having the same Interoperability Level
–       Level The attribute of an AIW and its AIMs to be executable in an AIF Implementation and to:

1.     Be proprietary (Level 1)

2.     Pass the Conformance Testing (Level 2) of an Application Standard

3.     Pass the Perform­ance Testing (Level 3) of an Application Standard.

Knowledge Base Structured and/or unstructured information made accessible to AIMs via MPAI-specified interfaces
Message A sequence of Records transported by Communication through Channels.
Normativity The set of attributes of a technology or a set of technologies specified by the applicable parts of an MPAI standard.
Performance The attribute of an Implementation of being Reliable, Robust, Fair and Replicable.
–       Assessment The normative document specifying the Means to Assess the Grade of Performance of an Implementation.
–       Assessment Means Procedures, tools, data sets and/or data set characteristics to Assess the Performance of an Implem­en­tation.
–       Assessor An entity Assessing the Performance of an Implementation.
Profile A particular subset of the technologies used in MPAI-AIF or an AIW of an Application Standard and, where applicable, the classes, other subsets, options and parameters relevant to that subset.
Record A data structure with a specified structure
Reference Model The AIMs and theirs Connections in an AIW.
Reference Software A technically correct software implementation of a Technical Specific­ation containing source code, or source and compiled code.
Reliability The attribute of an Implementation that performs as specified by the Application Standard, profile, and version the Implementation refers to, e.g., within the application scope, stated limitations, and for the period of time specified by the Implementer.
Replicability The attribute of an Implementation whose Performance, as Assessed by a Performance Assessor, can be replicated, within an agreed level, by another Performance Assessor.
Robustness The attribute of an Implementation that copes with data outside of the stated application scope with an estimated degree of confidence.
Scope The domain of applicability of an MPAI Application Standard
Service Provider An entrepreneur who offers an Implementation as a service (e.g., a recommendation service) to Users.
Standard A set of Technical Specification, Reference Software, Conformance Testing, Performance Assessment, and Technical Report of an MPAI application Standard.
Technical Specification (Framework) the normative specification of the AIF.

(Application) the normative specification of the set of AIWs belon­ging to an application domain along with the AIMs required to Im­plem­ent the AIWs that includes:

1.     The formats of the Input/Output data of the AIWs implementing the AIWs.

2.     The Connections of the AIMs of the AIW.

3.     The formats of the Input/Output data of the AIMs belonging to the AIW.

Testing Laboratory A laboratory accredited to Assess the Grade of  Performance of Implementations.
Time Base The protocol specifying how Components can access timing information
Topology The set of AIM Connections of an AIW.
Use Case A particular instance of the Application domain target of an Application Standard.
User A user of an Implementation.
User Agent The Component interfacing the user with an AIF through the Controller
Version A revision or extension of a Standard or of one of its elements.
Zero Trust A cybersecurity model primarily focused on data and service protection that assumes no implicit trust.