Abstract : This volume contains five papers presented during two
workshops, ‘‘First International Workshop on Asynchronous
Cellular Automata’’ (ACA 2010) and ‘‘Fifth International
Workshop on Natural Computing’’ (IWNC 2010), held at the
9th International Conference on Cellular Automata for
Research and Industry (ACRI 2010) in Ascoli Piceno (Italy)
in the period September 21–24th, 2010.
The ACA workshop is devoted to the theme of asynchrony
inside Cellular Automata. Cellular Automata are a wellknown
formal tool for modeling complex systems; they are
considered in many scientific fields and industrial applications.
Synchronicity is one of the main features of Cellular
Automata evolutions. Indeed, in the most common Cellular
Automata framework, all cells are updated simultaneously at
each discrete time step. Recent trends consider the modeling
of asynchronous systems based on local interactions. The
aim of this workshop is to bring together researchers dealing
with the theme of the asynchrony inside Cellular Automata.
The IWNC workshop is concerned with theoretical as
well as experimental studies of nature-inspired paradigms of
computations. More precisely, the scientific field of Natural
Computing encompasses theoretical and experimental
investigations of nature-inspired principles of information
processing, novel and emerging paradigms of computation
and computing architectures, and case studies of simulated or
real-world computing devices implemented in biological,
social, chemical, engineering, and physical systems.
Typical, but not exclusive, topics of the two workshops
are: various aspects of asynchronous cellular automata
(dynamics, complexity and computational issues, emergent
properties, models of parallelism and distributed systems,
models of real phenomena) and nature-inspired computation
and communication (DNA computation, cellular
automata, physics of computation, computation in living
cells, nanocomputing, evolutionary computing, artificial
chemistry, neural computation).
After an additional review process, three papers from
the ACA workshop and two from the IWNC workshop
were selected and included in this special issue. They are
now presented in an extended and improved form with
respect to the already refereed workshop version that
appeared in the proceedings of the ACRI 2010 conference.
The paper by L. Manzoni is about the dynamical behavior
of asynchronous cellular automata. The classical cellular
automata properties are adapted to the synchronous case
and related results are shown. In their paper, S. Bandini
et al. give an analysis of different update schemes for
asynchronous cellular automata and discuss the respective
effects by means of the class of 1D cellular automata.
L. Vanneschi et al. deal with genetic algorithms to evolve
asynchronous cellular automata and focus on learning
robustness with respect to the synchronous case. In the
article by J. B. Yune`s it is shown how universal computations
can be achieved on one-dimensional cellular automata
and a universal brick used in grids is given—it allows
to obtain intrinsic universal cellular automata. The article
by Sahu et al. discusses a molecular cellular automaton
recently introduced by the authors and shows novel
features that have never been proposed in conventional CA
We would like to warmly thank all referees for their
valuable contributions. We also want to thank Professor
Grzegorz Rozenberg for offering us the opportunity to
publish this special issue in Natural Computing.