Complexity through the Observation of Simple Systems

06/2009; DOI: 10.4204/EPTCS.1.3
Source: arXiv

ABSTRACT We survey work on the paradigm called "computing by observing." Its central feature is that one considers the behavior of an evolving system as the result of a computation. To this end an observer records this behavior. It has turned out that the observed behavior of computationally simple systems can be very complex, when an appropriate observer is used. For example, a restricted version of context-free grammars with regular observers suffices to obtain computational completeness. As a second instantiation presented here, we apply an observer to sticker systems. Finally, some directions for further research are proposed.

  • 01/2000; Addison-Wesley.
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    ABSTRACT: In biology and chemistry a standard proceeding is to conduct an experiment, observe its progress, and then take the result of this observation as the final output. Inspired by this, we have introduced P/O systems (A. Alhazov, C. Martı́n-Vide, Gh. Păun, Pre-Proc. of the Workshop on Membrane Computing 2003, Tarrragona, Spain;, where languages are generated by multiset automata that observe the evolution of membrane systems.Now we apply this approach also to more classical devices of formal language theory. Namely, we use finite automata observing the derivations of grammars or of Lindenmayer systems. We define several modes of operation for grammar/observer systems. In two of these modes a context-free grammar (or even a locally commutative context-free grammar) with a finite automaton as observer suffices to generate any recursively enumerable language. In a third case, we obtain a class of languages between the context-free and context-sensitive ones.
    Theoretical Computer Science. 01/2004;
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    ABSTRACT: We introduce the sticker systems, a computability model, which is an abstraction of the computations using the Watson-Crick complementarity as in Adleman's DNA computing experiment, [1]. Several types of sticker systems are shown to characterize (modulo a weak coding) the regular languages, hence the power of finite automata. One variant is proven to be equivalent to Turing machines. Another one is found to have a strictly intermediate power.
    Acta Informatica 01/1998; 35(5):401-420. · 0.47 Impact Factor

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