625 research outputs found
Fast cellular automata with restricted inter-cell communication: computational capacity
A d-dimensional cellular automaton with sequential input mode is a d-dimensional grid of interconnected interacting finite automata.
The distinguished automaton at the origin, the communication cell, is connected to the outside world and fetches the input sequentially.
Often in the literature this model is referred to as iterative array.
We investigate d-dimensional iterative arrays and one-dimensional cellular automata operating in real and linear time, whose inter-cell communication is restricted to some constant number of bits independent of the number of states. It is known that even one-dimensional one-bit iterative arrays accept rather complicated languages such as {apâprim} or {a2nânâN}[16]. We show that there is an infinite strict double dimension-bit hierarchy. The computational capacity of the one-dimensional devices in question is compared with the power of communication-restricted two-way cellular automata. It turns out that the relations are quite diferent from the relations in the unrestricted case. On passing, we obtain an infinite strict bit hierarchy for real-time two-way cellular automata and, moreover, a very dense time hierarchy for every k-bit cellular automata, i.e., just one more time step leads to a proper superfamily of accepted languages.4th IFIP International Conference on Theoretical Computer ScienceRed de Universidades con Carreras en InformĂĄtica (RedUNCI
Fast cellular automata with restricted inter-cell communication: computational capacity
A d-dimensional cellular automaton with sequential input mode is a d-dimensional grid of interconnected interacting finite automata.
The distinguished automaton at the origin, the communication cell, is connected to the outside world and fetches the input sequentially.
Often in the literature this model is referred to as iterative array.
We investigate d-dimensional iterative arrays and one-dimensional cellular automata operating in real and linear time, whose inter-cell communication is restricted to some constant number of bits independent of the number of states. It is known that even one-dimensional one-bit iterative arrays accept rather complicated languages such as {apâprim} or {a2nânâN}[16]. We show that there is an infinite strict double dimension-bit hierarchy. The computational capacity of the one-dimensional devices in question is compared with the power of communication-restricted two-way cellular automata. It turns out that the relations are quite diferent from the relations in the unrestricted case. On passing, we obtain an infinite strict bit hierarchy for real-time two-way cellular automata and, moreover, a very dense time hierarchy for every k-bit cellular automata, i.e., just one more time step leads to a proper superfamily of accepted languages.4th IFIP International Conference on Theoretical Computer ScienceRed de Universidades con Carreras en InformĂĄtica (RedUNCI
Proceedings of JAC 2010. Journées Automates Cellulaires
The second Symposium on Cellular Automata âJournÂŽees Automates Cellulairesâ (JAC 2010) took place in Turku, Finland, on December 15-17, 2010. The first two conference days were held in the Educarium building of the University of Turku, while the talks of the third day were given onboard passenger ferry boats in the beautiful Turku archipelago, along the route TurkuâMariehamnâTurku. The conference was organized by FUNDIM, the Fundamentals of Computing and Discrete Mathematics research center at the mathematics department of the University of Turku.
The program of the conference included 17 submitted papers that were selected by the international program committee, based on three peer reviews of each paper. These papers form the core of these proceedings. I want to thank the members of the program committee and the external referees for the excellent work that have done in choosing the papers to be presented in the conference. In addition to the submitted papers, the program of JAC 2010 included four distinguished invited speakers: Michel Coornaert (UniversitŽe de Strasbourg, France), Bruno Durand (UniversitŽe de Provence, Marseille, France), Dora Giammarresi (Universit` a di Roma Tor Vergata, Italy) and Martin Kutrib (Universitšat Gie_en, Germany). I sincerely thank the invited speakers for accepting our invitation to come and give a plenary talk in the conference. The invited talk by Bruno Durand was eventually given by his co-author Alexander Shen, and I thank him for accepting to make the presentation with a short notice. Abstracts or extended abstracts of the invited presentations appear in the first part of this volume.
The program also included several informal presentations describing very recent developments and ongoing research projects. I wish to thank all the speakers for their contribution to the success of the symposium. I also would like to thank the sponsors and our collaborators: the Finnish Academy of Science and Letters, the French National Research Agency project EMC (ANR-09-BLAN-0164), Turku Centre for Computer Science, the University of Turku, and Centro Hotel. Finally, I sincerely thank the members of the local organizing committee for making the conference possible.
These proceedings are published both in an electronic format and in print. The electronic proceedings are available on the electronic repository HAL, managed by several French research agencies. The printed version is published in the general publications series of TUCS, Turku Centre for Computer Science. We thank both HAL and TUCS for accepting to publish the proceedings.Siirretty Doriast
An evolutionary model for simple ecosystems
In this review some simple models of asexual populations evolving on smooth
landscapes are studied. The basic model is based on a cellular automaton, which
is analyzed here in the spatial mean-field limit. Firstly, the evolution on a
fixed fitness landscape is considered. The correspondence between the time
evolution of the population and equilibrium properties of a statistical
mechanics system is investigated, finding the limits for which this mapping
holds. The mutational meltdown, Eigen's error threshold and Muller's ratchet
phenomena are studied in the framework of a simplified model. Finally, the
shape of a quasi-species and the condition of coexistence of multiple species
in a static fitness landscape are analyzed. In the second part, these results
are applied to the study of the coexistence of quasi-species in the presence of
competition, obtaining the conditions for a robust speciation effect in asexual
populations.Comment: 36 pages, including 16 figures, to appear in Annual Review of
Computational Physics, D. Stauffer (ed.), World Scientific, Singapor
Computational universes
Suspicions that the world might be some sort of a machine or algorithm
existing ``in the mind'' of some symbolic number cruncher have lingered from
antiquity. Although popular at times, the most radical forms of this idea never
reached mainstream. Modern developments in physics and computer science have
lent support to the thesis, but empirical evidence is needed before it can
begin to replace our contemporary world view.Comment: Several corrections of typos and smaller revisions, final versio
Cellular automata with limited inter-cell bandwidth
AbstractA d-dimensional cellular automaton is a d-dimensional grid of interconnected interacting finite automata. There are models with parallel and sequential input modes. In the latter case, the distinguished automaton at the origin, the communication cell, is connected to the outside world and fetches the input sequentially. Often in the literature this model is referred to as an iterative array. In this paper, d-dimensional iterative arrays and one-dimensional cellular automata are investigated which operate in real and linear time and whose inter-cell communication bandwidth is restricted to some constant number of different messages independent of the number of states. It is known that even one-dimensional two-message iterative arrays accept rather complicated languages such as {apâŁp prime} or {a2nâŁnâN} (H. Umeo, N. Kamikawa, Real-time generation of primes by a 1-bit-communication cellular automaton, Fund. Inform. 58 (2003) 421â435). Here, the computational capacity of d-dimensional iterative arrays with restricted communication is investigated and an infinite two-dimensional hierarchy with respect to dimensions and messages is shown. Furthermore, the computational capacity of the one-dimensional devices in question is compared with the power of two-way and one-way cellular automata with restricted communication. It turns out that the relations between iterative arrays and cellular automata are quite different from the relations in the unrestricted case. Additionally, an infinite strict message hierarchy for real-time two-way cellular automata is obtained as well as a very dense time hierarchy for k-message two-way cellular automata. Finally, the closure properties of one-dimensional iterative arrays with restricted communication are investigated and differences to the unrestricted case are shown as well
Millions of 5-State n^3 Sequence Generators via Local Mappings
In this paper, we come back on the notion of local simulation allowing to
transform a cellular automaton into a closely related one with different local
encoding of information. In a previous paper, we applied it to the Firing Squad
Synchronization Problem. In this paper, we show that the approach is not tied
to this problem by applying it to the class of Real-Time Sequence Generation
problems. We improve in particular on the generation of n 3 sequence by using
local mappings to obtain millions of 5state solution, one of them using 58
transitions. It is based on the solution of Kamikawa and Umeo that uses 6
states and 74 transitions. Then, we explain in which sense even bigger classes
of problems can be considered
Fast cellular automata with restricted inter-cell communication: computational capacity
A d-dimensional cellular automaton with sequential input mode is a d-dimensional grid of interconnected interacting finite automata.
The distinguished automaton at the origin, the communication cell, is connected to the outside world and fetches the input sequentially.
Often in the literature this model is referred to as iterative array.
We investigate d-dimensional iterative arrays and one-dimensional cellular automata operating in real and linear time, whose inter-cell communication is restricted to some constant number of bits independent of the number of states. It is known that even one-dimensional one-bit iterative arrays accept rather complicated languages such as {apâprim} or {a2nânâN}[16]. We show that there is an infinite strict double dimension-bit hierarchy. The computational capacity of the one-dimensional devices in question is compared with the power of communication-restricted two-way cellular automata. It turns out that the relations are quite diferent from the relations in the unrestricted case. On passing, we obtain an infinite strict bit hierarchy for real-time two-way cellular automata and, moreover, a very dense time hierarchy for every k-bit cellular automata, i.e., just one more time step leads to a proper superfamily of accepted languages.4th IFIP International Conference on Theoretical Computer ScienceRed de Universidades con Carreras en InformĂĄtica (RedUNCI
- âŠ