
Immune System Modelling and Simulation
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additional parameters, m
0
, A
0
, ∂A to calculate the vector in
the following way: (i) fi rst, set Affi nity(m) = 0 for m < m
0
; this
provides a threshold level below which binding cannot occur;
(ii) set Affi nity(m
0
) to the parameter A
0
; (iii) set the increase of
strength on increasing a match by one bit to be the inverse of the
ratio of number of clones with match m + 1 and m multiplied by
∂A.
Affi nity (m – 1)
Affi nity (m)
= ∂A .
(
NBIT
m
)
(
NBIT
)
m – 1
.
This defi nition allows setting the lower end value of
Affi nity(m) and the steepness of its increase, as the number
of matching bits is incremented (Figure 35). ...