I'm new to this discussion, so maybe someone can explain this to me.
Why do you guys refer to (

,

) as 'caps' ?
Also, while the formula
is certainly nice, it's not very intuitive.
In order to actually understand what the constant values represent, i changed it a bit to

.
Therefore with k ~ 1, I'm interpreting c as a half-value constant and thus not a 'cap' at all?