Foreword: cellular automata and applications

International audienceThis special issue contains four papers presented during theworkshop, ‘‘18th International Workshop on CellularAutomata and Discrete Complex Systems’’ (Automata2012), held in La Marana, Corsica island (France) in theperiod September 19–21th, 2012.The aim of this workshop is to establish and maintain apermanent, international, multidisciplinary forum for thecollaboration of researchers in the field of Cellular Automata(CA) and Discrete Complex Systems (DCS), providea platform for presenting and discussing new ideas andresults, and support the development of theory and applicationsof CA and DCS.Typical, but not exclusive, topics of the workshop are:dynamics aspects, algorithmic, computational and complexityissues, emergent properties, formal language processing,models of parallelism and distributed systems,phenomenological descriptions, scientific modeling andpractical applications.After an additional review process, four papers wereselected and included in this special issue. They are nowpresented in an extended and improved form with respectto the already refereed workshop version that appeared inthe proceedings of Automata 2012.The paper ‘‘Computation of Functions on n Bits byAsynchronous Clocking Cellular Automata’’ by MichaelVielhaber aims at proving that different functions on binaryvectors can be computed by changing the updating schemefrom a fully synchronous to an asynchronous one on somefixed CA local rule.In their paper ‘‘Solving the Parity Problem in One–Dimensional Cellular Automata’’, Heather Betel, PedroP. B. de Oliveira, and Paola Flocchini deal with the parityproblem in one–dimensional cellular automata (CA): a CAlocal rule solves the parity problem if, starting from anyinitial configuration, the CA converges to the 0–configuration(resp., the 1–configuration) if and only if the initialconfiguration contains an even number of 1s (resp., an oddnumber of 1s). In particular, authors focus on the neighborhoodsize of CA rules solving the problem.Murillo G. Carneiro and Gina M. B. Oliveira present inthe paper ‘‘Synchronous Cellular Automata-Based Schedulerinitialized by Heuristic and modeled by a Pseudolinearneighborhood’’ two approaches based on CA to thetask scheduling problem in multiprocessor systems.The implementation of cellular automata on processorarrays is considered by Jean-Vivien Millo and Robertde Simone in the paper ‘‘Explicit routing schemes forimplementation of cellular automata on processor arrays’’.They deal with the trade-offs between the generality of theCA neighborhood and the limited expressive power providedby physical platforms. This is an extremely hot topicwhich will help in turning CA towards real extendedapplications.We would like to warmly thank the authors for theirwork and effort which made this special issue possible.Special thanks go to all referees for their valuable contributionsboth during the selection and the final reviewprocess. Finally, we also want to thank Professor GrzegorzRozenberg for offering us the opportunity to publish thisspecial issue in Natural Computing

Methodology for predicting and/or compensating the behavior of optical frequency comb

RESUMEN: Optical frequency comb spectrum can change its behavior due to temperature fluctuations, normal dispersion, and mechanical vibrations. Such limitations can affect the peak power and wavelength separation of comb lines. In the propagation through single−mode fiber, the linear and non−linear phenomena can modify spectral shape, phase shifts and flatness of spectrum. To find a strategy of compensation, the PhD thesis is focused on a prediction methodology based on fuzzy cellular automata, intuitionistic fuzzy sets and fuzzy entropy measures. The research work proposes a predictor called intuitionistic fuzzy cellular automata based on mean vector and a validation measure called general intuitionistic fuzzy entropy based on adequacy and non−adequacy. In the accomplished experiments, the method was used in three experiments: mode−locked lasers, cascaded intensity modulators−Mach Zehnder modulators, and microresonator ring. The obtained results showed that the power and phase distortions were reduced by using a pulse shaper, where the method was programmed. In addition, the stability and/or instability of spectrum were found for the microresonator ring