Useful daylight illuminances
: A replacement for daylight factors.
By overlaying Isofootcandle Plots, a rough idea of illuminances
can be accomplished by adding the values of each contour where they intersect (figure 11.2).
It would be beneficial to have a time- and cost-effective method to predict illuminances
in the surgical site and to test if a virtual prototype of a surgical luminaire complies to [IEC 2009], before building the device.
Later, two advanced daylight metrics were brought into use: daylight autonomy (Reinhart, 2002; Tzempelikos and Athienitis, 2005, 2007) and useful daylight illuminances
(Nabil and Mardaljevic, 2005, 2006; Shen and Tzempelikos, 2010).
Vienot and others  used semantic differential scales to evaluate nine combinations of three illuminances
and three CCT.
inside a room are, however, not only comparative to the peripheral illuminance
but also depend on the exact sky luminance dissemination at any given time.
Impact of lighting arrangements and illuminances
on different impressions of a room.
6(a) shows the BER performance of the solar cell Rx at different illuminances
with the corresponding eye-diagrams.
There is no doubt that streets with higher illuminances
are seen as safer, but how high an illuminance
In These Trials, the Left-Hand Field Was Fixed at 25 cd, the Right-Hand Field Was Set to One of Three Light Levels 17 cd 25 cd 35 cd Right-hand side 7 18 29 Same (equally bright) 29 23 12 Left-hand side 6 1 1 Fotios and Cheal  used discrimination to compare side-by-side booths at mesopic illuminances
and their procedure included counterbalancing of the position of their stimuli.
on all rings were summed and total luminous flux of light source was evaluated.
Recognizing limitations of the daylight-factor metric, various researchers have proposed a number of dynamic daylight metrics, such as Daylight Autonomy (Association Suisse des Electriciens, 1989), Useful Daylight Illuminances
(Nabil and Mardaljevic, 2005), Continuous Daylight Autonomy (Rogers, 2006), etc.