attention:extent to which the task does (foreground) or does not (background) require the full attention of the parties in the communication

audio conferencing: telephone service that does not rely on amplification of the voice signal in very close proximity to the recipient's ear

audio delay: mean time required for an audio signal to reach the listener’s ear

audio protocol: set of rules defining the way audio information is represented in a network

audio telephony: "ordinary" telephone service as distinct from audio conferencing

audio/video asynchrony: when audio and video information that leaves one communicating party is received by the other communicating party at different times (e.g. typically the audio information arrives before the video information in an asynchronous situation)
NOTE: It is calculated as audio delay subtracted from video delay (e.g. if audio delay is 50 ms and video delay is 200 ms, then asynchrony is 150 ms; if audio delay is 100 ms and video delay is 50 ms, then asynchrony is -50 ms).

audio: all signals that are audible to human beings, including speech, music and background noise

avatar communication: use of a service that transmits voice or text in real-time over a telecommunication network in combination with a graphical (human) representation of the speaker

background experience: overall strength of pre-existing experience held by the communication parties that is relevant to the task (experience of the communication service and goal task requirements)

CD quality: audio quality with a 44.1 kHz sampling rate without compression

common ground: extent to which the communication parties have the same understanding of the goal and context of the communication and the concepts involved

communication activity: what the end-users (want to) do with a communication service (e.g. social chatting, buying or selling shares, conducting a job interview, etc.)

communication media: types of information with which humans communicate
NOTE: Examples are text, audio and moving image (graphics and video).

communication service: user-initiated service that is provided via a telecommunication network for people to share information
NOTE: Examples are speech telephony, email, videoconferencing, avatar-telephony, audio conferencing.

communication situation: combination of task, motive, content and user (group) characteristics

communication task: what the end-users (want to) do with a communication service (e.g. social chatting, buying or selling shares, conducting a job interview, etc.)

communicative behaviour: end-user behaviour while using a communication service, including turn taking, interruptions, verbal and non-verbal back-channels and gaze

conversational text: See real-time text.

data communication: use of a service that transmits personal computer-based information (e.g. presentation slides)

data conferencing: See data communication

difficulty: extent to which a task is difficult or complex versus simple or routine

duration: length of time of the communication task

dyadic communication: (distance) communication between two people

effectiveness: accuracy and completeness with which specified users can achieve specified goals in particular environments
NOTE: See ISO 9241 definition.

efficiency: resources expended in relation to the accuracy and completeness of goals achieved
NOTE: See ISO 9241 definition.

emotiveness: extent to which a task has a strong emotional content

end-users: people who use a communication service

extrinsic goal: extent to which a communication goal has an objective and observable outcome

face-to-face (videoconferencing): the use of video communication to see the person who is talking

form impression: extent to which the task requires that the communication partners perceive characteristics of each other, such as personality and intelligence

frame-rate: frequency by which a full frame is updated, in the case of video frame-rate sometimes called video temporal resolution or image frequency

general type of task: aim of the communication stated at its most general level appropriate for all the parties concerned

geographical remoteness: extent to which the communication parties are physically dispersed and separated

group: (distance) communication between three or more people
NOTE: Either in a point-to-point or a multi-point configuration.

high quality videoconferencing: video communication using an analogue simulation of PAL quality, with technical parameter values: delay < 40 ms; frame rate 25 fps; resolution 4CIF (PAL); no packet loss
NOTE: A laboratory and field study set-up used for some user tests

impression of communication partner: overall rating of the communication partner on multiple person-perception characteristics

impression of task performed: extent to which the service users believe they achieved a good result

instruction task: a communication task to between two or more people collaborate in order to transfer information. The communication may be more one-way and unequal with respect to expertise.

interpersonal perception: extent to which the perception of the other person's attributes (how likeable, intelligent, friendly etc.) is positive or negative

intrinsic goal: communication goal that is subjective and personally experienced, with the participants communicating for its own sake rather than to achieve some objective task

knowledge of other: overall strength of the pre-existing personal knowledge that the communication parties have of each other

media effects: effect a particular communication medium has on an end-users task outcome, communicative behaviour, attitudes and beliefs

media preferences: subjective assessment by users or user groups of when a given communication medium is preferred over another

media/medium: see Communication Media/Medium

monitor size: number in inches of the diagonal of the image screen on a screen

multimedia communication: use of a service that transmits voice, video and data signals in real-time over a telecommunication network

multimedia conferencing: service for transmitting voice, video and data signals over a telecommunication network

multi-point: distance communication between three or more locations

negotiation task: a communication task between people in order to achieve an agreement

network performance: the ability of a network or network portion to provide the functions related to communications between users.
NOTE 1 – Network performance applies to the network provider’s planning, development, operations and maintenance and is the detailed technical part of QoSO. NOTE 2 –Network performance parameters are meaningful to network providers and are quantifiable at the part of the network which they apply. NOTE: From ITU-T Recommendation E.800.

network quality of service: degree of conformance of the service delivered to a user by a provider with an agreement between them
NOTE: From ITU-T Recommendation E.860.

packet loss: loss of one or more packet that can be described using a certain statistical model

packet size: magnitude of a unit of data transmitted over a packet switching network as part of a message transferred in number of Bytes

person perception: the extent to which the perception of the other person’s attributes (how likeable, intelligent, friendly, etc.) is positive or negative

personal involvement: extent to which the communication parties are committed to the outcome of the task or perform the task more on behalf of another party than themselves

persuasion task: a communication task in which one person attempts to make one or more other do or believe something that previously they would probably not do or believe. The communication involves giving another person a good reason to do something or making someone believe something.

point-to-point: communication between two locations

problem solving task: a communication task where the primary goal is for two or more people to collaborate and share relatively equal but different expertise to find a solution to a problem.

quality of experience (1) (QoE): measure of user performance based on both objective and subjective psychological measures of using an ICT service or product
NOTE 1: It takes into account technical parameters (e.g. QoS) and usage context variables (e.g. communication task) and measures both the process and outcomes of communication (e.g. user effectiveness, efficiency, satisfaction and enjoyment).
NOTE 2: The appropriate psychological measures will be dependent on the communication context. Objective psychological measures do not rely on the opinion of the user (e.g. task completion time measured in seconds, task accuracy measured in number of errors). Subjective psychological measures are based on the opinion of the user (e.g. perceived quality of medium, satisfaction with a service).
EXAMPLE: A service provider may conclude that a service with a certain level of QoS used for a particular communication situation offers users excellent QoE, whist with a different level of QoS provides poor QoE.
NOTE: ETSI TR 102 643 definition

quality of experience (2) (QoE): the overall acceptability of an application or service, as perceived subjectively by the end-user.
NOTE 1: Quality of experience includes the complete end-to-end system effects (client, terminal, network, services infrastructure, etc.).
NOTE 2: Overall acceptability may be influenced by user expectations and context.
NOTE : ITU-T Recommendation P.10/G.100 Amendment 2 definition

quality of service experienced/perceived by customer/user (QoSE): a statement expressing the level of quality that customers/users believe they have experienced.
NOTE 1: The level of QoS experienced and/or perceived by the customer/user may be expressed by an opinion rating.
NOTE 2: QoSE has two main man components: quantitative and qualitative. The quantitative component can be influenced by the complete end-to-end system effects (network infrastructure).
NOTE 3: The qualitative component can be influenced by user expectations, ambient conditions, psychological factors, application context, etc.
NOTE 4: QoSE may also be considered as QoSD (QoS delivered/achieved by service provider) received and interpreted by a user with the pertinent qualitative factors influencing his/her perception of the service.
NOTE : ITU-T E.800 definition.

quality of service: Totality of characteristics of a telecommunications service that bear on its ability to satisfy stated and implied needs of the user of the service.
NOTE: ITU-T E.800 definition.

real-time communication service: a service with which users expect to share information instantly and continuously with one or more other user. A real-time communication service generates and delivers either text, audio (such as speech), graphics, video and data or some combination of these communication media.
NOTE: The information sharing process occurs either by: (1) a person interacting via technology directly to another person (person-to-person) or; (2) a person interacting with a machine (person-to-machine).
EXAMPLE: An example real-time person-to-person communication service is videoconferencing and an example real-time person-to-machine communication service is Live TV.

real-time text: service for transmitting alpha-numeric characters in real-time over a telecommunication network

real-time transport protocol: a standardized packet format for delivering audio and video over the Internet.
NOTE 1: It was developed by the Audio-Video Transport Working Group of the IETF and first published in 1996 as RFC 1889, and superseded by RFC 3550 in 2003.
NOTE 2: RTP is frequently used in streaming media systems (together with the RTSP) as well as in videoconferencing and push to talk systems. For these it carries media streams controlled by H.323 or Session Initiation Protocol (SIP) signaling protocols, making it the technical foundation of the Voice over IP industry.

real-time: describes information and communication technologies that are able to generate and deliver information in a time-frame similar to the real-life process that it is assisting
EXAMPLE 1: Real-time charging and billing information is to be generated, processed, and transported to a desired conclusion in less than 1 second
EXAMPLE 2: Refers to the generation of network management information in a time frame comparative to the real life process that it is controlling or monitoring

relation grouping: main category for the type of relationship between the communication parties

relation to partner: overall strength of the pre-existing personal relation between the communication parties

remote inspection videoconferencing: the use of video communication to observe an object or environment while also engaging in person-to-person communication using speech communication. It enables a person to see what is talked about rather than who is talking. The minimal configuration for remote inspection is one-way video with two-way speech
NOTE: The service is sometimes also called Tele-inspection, Tele-data, See what I See (SWIS).

resolution: term denoting the degree of detail which can be created by a particular visual display system expressed in pixels in x- and y-directions

satisfaction: comfort and acceptability of the work system to its users and other people affected by its use
NOTE: ISO 9241 definition.

service (medium) preference: extent to which the service user would chose that service again for the same kind of communication in the future

situation formality: relative amount of ceremonious or conventional communication versus casual or unconstrained communication

specific type of task: type of communication stated at its most specific level if appropriate, such as the name of an experimental task performed in a laboratory

talking head video: application of videoconferencing for a person to see their other communication partner(s)

task effectiveness: accuracy and completeness which specified service users can achieve specified goals in particular environments

task efficiency: resources expended in relation to the accuracy and completeness of goals achieved

task elements: features of tasks that can be expected to vary (e.g., extrinsic-intrinsic origin, symmetrical-asymmetrical balance, originator-recipient role, ego involvement level, information dependency, sociability level)

task goal: aim or object towards which the communication is directed

task outcome: extent to which task performance dependent on the medium

task symmetry: extent to which the parties in communication are less or more equal with respect to expertise or control of the interaction

task: what users of communicative technology actually do in order to accomplish some task goal
NOTE: In experiments tasks may be described to the participants or they are embedded in scenarios as a part of a situation.

teledata: task involving communication with video, graphics and/or audio which represents data rather than the presence of other users

telephony: service for transmitting voice signals in real-time over a telecommunication network

telepresence: task involving communication with or awareness of other users

text communication: use of a service that transmits alpha-numeric characters in real-time over a telecommunication network
NOTE: Also known as real-time text and conversational text.

up-time: the time that a communication service provides a connection to a user to enable the intended use of the service (rather than having an unplanned break in connection)

urgency: extent to which a task is particularly urgent or under particular time pressure

usability: effectiveness, efficiency, and satisfaction with which specified users achieve specified goals in particular environments
NOTE: See ISO 9241 definition.

user groups: end-users who with respect to their usage of communication service may be grouped together (e.g. business executives, university students, grandparents, deaf people, etc.)

user satisfaction: comfort and acceptability of the task performance to the service user. Operationalized as the extent to which the service is assessed to a pleasant communication medium for the task

video as data: application of videoconferencing for a person or persons to see something other than the other communication partner(s)

video communication: use of a service that transmits voice and video signals in real-time over a telecommunication network, i.e. use of videotelephony or videoconferencing
NOTE: Sometimes called audiovisual communication when including transfer of information between user and machine/host in addition to from user to user
NOTE: For the current report the communication involves a loud-speaking audio system and not a handset.

video delay: time between the input of the first pixel of a particular picture at the sending end encoder and the output of the pixel from the decoder at the receiving end

video protocol: set of rules defining the way video information is represented in a network

videoconferencing: service for transmitting voice and video signals in real-time over a telecommunication network for group communication
NOTE: The audio system is considered loud-speaking and not with a handset or headset.

videotelephony: service for transmitting voice and video signals in real-time over a telecommunication network for dyadic communication