Knowledge Base

NoldusHub - N-Linx Agent and Connectivity

NoldusHub 1.8 is a data integration platform by Noldus. The following resources document the signals available per device across different versions of NoldusHub.

Signals Available in NoldusHub v1.4 (Per Device)

Shimmer GSR+

1. Baseline conductivity is the measured conductivity from which transient peak responses are removed. Conductivity is expressed in microSiemens (µS).
2. Average peak rate and heart rate are expressed as the (average) number of peaks/beats per minute (min^-1).
3. The raw PPG signal is a normalized, unitless light absorption measure. It reflects the size of expansion/constriction of small blood vessels induced by local blood pressure fluctuation due to the beating of the heart.
4. Inter-beat intervals, i.e. the interval between two subsequent heart beats, is expressed in milliseconds (msec).

Shimmer EXG

Tobii Pro Remote Eyetrackers

1. Positions on the screen are normalized values: left (X) = 0, right (X) = 1; top (Y) = 0, bottom (Y) = 1.
2. Movement state can be "Saccade" (i.e. moving), "Fixation", or "Undefined".
3. Gaze X and Gaze Y are averaged over both eyes if data from both are available. Otherwise, values are limited to the available data only.

Eyetech VT3-mini

1. Positions on the screen are normalized values: left (X) = 0, right (X) = 1; top (Y) = 0, bottom (Y) = 1.
2. Movement state can be "Saccade" (i.e. moving), "Fixation", or "Undefined".
3. Gaze X and Gaze Y are averaged over both eyes if data from both are available. Otherwise, values are limited to the available data only.

Insight: Facial Expressions

Facial Expressions are "Insights": signals that are derived by applying an algorithm to one or more measured signals. To qualify as an insight, the algorithm used should be validated scientifically to produce a signal that reflects a psychologically meaningful factor. In the case of Facial Expressions, the measured signal is a face video of the participant. The algorithm is a set of video processing routines that quantify facial motor action unit responses and recipes to estimate emotional expressions based on those responses according to the Facial Action Coding System.

Facial Expression signals available in NoldusHub:

1. Relative expression intensities are normalized values: minimum = 0, maximum = 1.

Insight: Cognitive Workload

Cognitive Workload is an "Insight": a psychologically meaningful factor that is estimated from measured physical and physiological signals. The Cognitive Workload insight is obtained from measured pupil sizes and environmental light intensity, using a scientifically validated algorithm.

Cognitive Workload signals available in NoldusHub:

1. Relative Cognitive Load and Cognitive Load Confidence intensities are normalized values: minimum = 0, maximum = 1.

Signals Available in NoldusHub v1.6 (Per Device)

Shimmer GSR+

1. Baseline conductivity is the measured conductivity from which transient peak responses are removed. Conductivity is expressed in microSiemens (µS).
2. Average peak rate and heart rate are expressed as the (average) number of peaks/beats per minute (min^-1).
3. The raw PPG signal is a normalized, unitless light absorption measure. It reflects the size of expansion/constriction of small blood vessels induced by local blood pressure fluctuation due to the beating of the heart.
4. Inter-beat intervals, i.e. the interval between two subsequent heart beats, is expressed in milliseconds (msec).

Shimmer EXG

Tobii Pro Remote Eyetrackers

1. Positions on the screen are normalized values: left (X) = 0, right (X) = 1; top (Y) = 0, bottom (Y) = 1.
2. Movement state can be "Saccade" (i.e. moving), "Fixation", or "Undefined".
3. Gaze X and Gaze Y are averaged over both eyes if data from both are available. Otherwise, values are limited to the available data only.

Eyetech VT3-mini

1. Positions on the screen are normalized values: left (X) = 0, right (X) = 1; top (Y) = 0, bottom (Y) = 1.
2. Movement state can be "Saccade" (i.e. moving), "Fixation", or "Undefined".
3. Gaze X and Gaze Y are averaged over both eyes if data from both are available. Otherwise, values are limited to the available data only.

Insight: Facial Expressions

Facial Expressions are "Insights": signals that are derived by applying an algorithm to one or more measured signals. To qualify as an insight, the algorithm used should be validated scientifically to produce a signal that reflects a psychologically meaningful factor. In the case of Facial Expressions, the measured signal is a face video of the participant. The algorithm is a set of video processing routines that quantify facial motor action unit responses and recipes to estimate emotional expressions based on those responses according to the Facial Action Coding System.

Facial Expression signals available in NoldusHub: