d	distance sensor to opposing wall (mm)
${}_i$	index numbering of detected events at the door (-)
${}_j$	index numbering the loops (-)
$s_{1,2}$	measured value of the ToF sensor (mm)
$\mathsf{\Delta }s$	difference (mm)
t	time (sec)
$\mathsf{\Delta }t$	time step (sec)
$\mathsf{\Delta }P$	change (Person)
R	persons in the room (Person)
D	door
DS	door sensor
GDPR	General Data Protection Regulation
INRUD	International Network for the Rational Use of Drugs
MD	motion detector
PIR	passive infrared sensor
ToF	Time of Flight
WHO	World Health Organisation