Evolution and observation: A new way to look at membrane systems

An architecture for investigating the dynamical behaviour of biological systems is proposed by using the concepts of "behaviour" and "observer". The behaviour of a biological system is the sequence of states traversed as time passes; the observer is a device translating this behaviour into a readable output. As an instance of this architecture we investigate P/O systems constituted by a membrane system and a multiset finite automaton observer. We first characterize the infinite behaviours of conservative systems, i.e., systems whose number of objects is constant. These systems behave very regularly. For more sophisticated systems we then use also more complicated multiset automata as observers: they map the configurations into an output alphabet and thus we obtain words describing the entire computations. Even for seemingly simple membrane systems using only non-cooperative rules and regular-like observers through this combination a great power emerges, in our case computational universality. © Springer-Verlag Berlin Heidelberg 2004.