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13th International Conference on Membrane Computing - MTA Sztaki

13th International Conference on Membrane Computing - MTA Sztaki

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T. Hinze, B. Schell, M. Schumann, C. Bodenstein<br />

M = {(brusselator, 1), (repressilator, 1), (goodwin, 1), (separator, 1), (mod17, 1)}<br />

P = {0 :ModuleC<strong>on</strong>nect(repressilator[1] → mod17[1], {(Z, C)})}<br />

goodwin[1]<br />

brusselator[1]<br />

T T T T<br />

B B B 3 B 4 B 5<br />

separator[1]<br />

B 1<br />

T<br />

1<br />

repressilator[1]<br />

C<br />

C<br />

mod17[1]<br />

0 0 0 1 1<br />

0.8<br />

0<br />

0<br />

0<br />

1<br />

1<br />

1<br />

1<br />

0<br />

1<br />

0<br />

c<strong>on</strong>centrati<strong>on</strong> (a.u.)<br />

0.6<br />

0.4<br />

0<br />

1<br />

1<br />

1<br />

0<br />

0.2<br />

0<br />

1<br />

0<br />

0<br />

1<br />

T<br />

1 2<br />

0<br />

1 0<br />

0<br />

0<br />

0<br />

0 200 400 600 800 1000 1200<br />

time (a.u.)<br />

Fig. 8. Dynamical behaviour of the frequency divider 1:6 obtained by replacing the<br />

Brusselator with the Repressilator module and skipping the binary signal separator<br />

again (left: cycle of state transiti<strong>on</strong>s, right: counts together with divider output)<br />

leads to the observati<strong>on</strong> that now a frequency divider 1:6 with reliable operati<strong>on</strong><br />

occurred, see Figure 8. After a short transient phase, a stable cycle c<strong>on</strong>sisting<br />

of six state transiti<strong>on</strong>s emerged when the Repressilator’s parameterisati<strong>on</strong> as<br />

introduced before is applied. We assume the reas<strong>on</strong> for that is a deterministically<br />

maintained perturbance of the binary functi<strong>on</strong>’s computati<strong>on</strong> in the logical<br />

unit. C<strong>on</strong>trary to the previously discussed frequency divider 1:5, the Repressilator<br />

implies an undersupply of the counting signal with its logical 1-level. This<br />

prevents the system from completing the computati<strong>on</strong> and forces the release of<br />

an intermediate computati<strong>on</strong>al state taken as output.<br />

3.5 Frequency Divider 1:3 by Usage of the Goodwin Module<br />

The Goodwin module al<strong>on</strong>g with its capability of rudimentary plated oscillatory<br />

signal generati<strong>on</strong> appears to be another interesting candidate to drive our<br />

frequency divider. By means of the P meta framework<br />

Π FD3 =(M,P) with<br />

M = {(brusselator, 1), (repressilator, 1), (goodwin, 1), (separator, 1), (mod17, 1)}<br />

P = {0 :ModuleC<strong>on</strong>nect(goodwin[1] → mod17[1], {(X, C)})}<br />

we achieve <strong>on</strong>ce more a modified qualitative behavioural pattern, this time a<br />

frequency divisi<strong>on</strong> 1:3, see Figure 9. After a short transient phase, the system<br />

persistently cycles through three states out of 17 from the original model. It<br />

236

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