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two extreme parameters setting. The
b
histograms represent the case when the ac-
tivation pressure is too strong and all the antibodies live forever. The
c
histograms
show just the opposite situation where the suppression pressure outweighs and all
the types of antibodies die immediately after they are introduced into the system.
5
Learning the Antigens
The last part of our experiments is concerned with testing of the system with anti-
gens. For our tests we selected Jaccard and Needham anity measure with trans-
formation T and a set of five types of antigens. We searched for such a set of five
types where the anity to each other was the smallest. A new object represent-
ing a type of antigens was injected into the system after every 5 iterations of the
algorithm. After a copy of the fifth type of antigen the next injected object was a
copy of the first one. Figure 5 presents two sample histograms with life spans of the
subsequently injected objects. Every bar in the histograms represents a life span of
a single object. There are five colors of bars because these are life spans of objects
of the five types of patterns. There is a hundred life spans in each of the histograms
so each experiment took 500 iterations. The bars are grouped by the number of
presentation of the five types of antigens - each of them was presented 20 times.
Initial concentration of the added objects was set to 1.
In Figure 5 the histogram shows the case where all the five types of antigens were
presented from the beginning of the experiment. It was expected that shortly after
the beginning of experiment there would appear multiple copies of objects repre-
senting the same types of antigens. However it was also expected that after some
time the network would modify its set of types of antibodies and new types that are
able to recognize the injected antigens would appear. Eventually the modification
of the network would produce the desired effect i.e. the concentration of the ob-
jects representing antigens would shrink below the minimal limit and they would
be eliminated. The histogram shows that after some time the network of antibodies
adapted to the presence of new types of antigens.
80
antigen 1
antigen 2
antigen 3
antigen 4
antigen 5
70
60
50
40
30
20
10
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Fig. 5.
Histogram of lifetime of objects representing five types of antigens presented cycli-
cally. X axis represents the number of the presentation of a type of antigen and Y axis -
the lifetime of the injected object
