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Visual Models of Plants Interacting with Their Environment
, 1996
"... Interaction with the environment is a key factor affecting the development of plants and plant ecosystems. In this paper we introduce a modeling framework that makes it possible to simulate and visualize a wide range of interactions at the level of plant architecture. This framework extends the form ..."
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Cited by 153 (17 self)
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Interaction with the environment is a key factor affecting the development of plants and plant ecosystems. In this paper we introduce a modeling framework that makes it possible to simulate and visualize a wide range of interactions at the level of plant architecture. This framework extends the formalism of Lindenmayer systems with constructs needed to model bidirectional information exchange between plants and their environment. We illustrate the proposed framework with models and simulations that capture the development of tree branches limited by collisions, the colonizing growth of clonal plants competing for space in favorable areas, the interaction between roots competing for water in the soil, and the competition within and between trees for access to light. Computer animation and visualization techniques make it possible to better understand the modeled processes and lead to realistic images of plants within their environmental context. CR categories: F.4.2 [Mathematical Logi...
Toward a Viable, SelfReproducing Universal Computer
 Physica D
, 1996
"... Selfreproducing, cellular automatabased systems developed to date broadly fall under two categories; the first consists of machines which are capable of performing elaborate tasks, yet are too complex to simulate, while the second consists of extremely simple machines which can be entirely impleme ..."
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Cited by 28 (1 self)
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Selfreproducing, cellular automatabased systems developed to date broadly fall under two categories; the first consists of machines which are capable of performing elaborate tasks, yet are too complex to simulate, while the second consists of extremely simple machines which can be entirely implemented, yet lack any additional functionality aside from selfreproduction. In this paper we present a selfreproducing system which is completely realizable, while capable of executing any desired program, thereby exhibiting universal computation. Our starting point is a simple selfreproducing loop structure onto which we "attach" an executable program (Turing machine) along with its data. The three parts of our system (loop, program, data) are all reproduced, after which the program is run on the given data. The system reported in this paper has been simulated in its entirety; thus, we attain a viable, selfreproducing machine with programmable capabilities. 1 Introduction The study of art...
From cells to computers: Computing with membranes (P systems
 Biosystems
, 2001
"... The aim of this paper is to introduce to the reader the main ideas of computing with membranes, a recent branch of (theoretical) molecular computing. In short, in a celllike system, multisets of objects evolve according to given rules in the compartments defined by a membrane structure and compute ..."
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Cited by 28 (0 self)
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The aim of this paper is to introduce to the reader the main ideas of computing with membranes, a recent branch of (theoretical) molecular computing. In short, in a celllike system, multisets of objects evolve according to given rules in the compartments defined by a membrane structure and compute natural numbers as the result of halting sequences of transitions. The model is parallel, nondeterministic. Many variants have already been considered and many problems about them were investigated. We present here some of these variants, focusing on two central classes of results: (1) characterizations of the recursively enumerable sets of numbers and (2) possibilities to solve NPcomplete problems in polynomial — even linear — time (of course, by making use of an exponential space). The results are given without proofs. An almost complete bibliography of the domain, at the middle of October 2000, is
Coevolving NonUniform Cellular Automata to Perform Computations
, 1996
"... A major impediment of cellular automata (CA) stems from the difficulty of utilizing their complex behavior to perform useful computations. Recent studies by [ Packard, 1988, Mitchell et al., 1994b ] have shown that CAs can be evolved to perform a computational task. In this paper nonuniform CAs are ..."
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Cited by 26 (5 self)
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A major impediment of cellular automata (CA) stems from the difficulty of utilizing their complex behavior to perform useful computations. Recent studies by [ Packard, 1988, Mitchell et al., 1994b ] have shown that CAs can be evolved to perform a computational task. In this paper nonuniform CAs are studied, where each cell may contain a different rule, in contrast to the original, uniform model. We describe experiments in which nonuniform CAs are evolved to perform the computational task using a local, coevolutionary algorithm. For radius r = 3 we attain peak performance values of 0:92 comparable to those obtained for uniform CAs (0:93 \Gamma 0:95). This is notable considering the huge search spaces involved, much larger than the uniform case. Smaller radius CAs (previously unstudied in this context) attain performance values of 0:93 \Gamma 0:94. For r = 1 this is considerably higher than the maximal possible uniform CA performance of 0:83, suggesting that nonuniformity reduces con...
Automatic Discovery of SelfReplicating Structures in Cellular Automata
 IEEE Transactions on Evolutionary Computation
, 1997
"... Previous computational models of selfreplication using cellular automata have been manually designed, a difficult and timeconsuming process. We show here how genetic algorithms can be applied to automatically discover rules governing selfreplicating structures. The main difficulty in this problem ..."
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Cited by 22 (6 self)
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Previous computational models of selfreplication using cellular automata have been manually designed, a difficult and timeconsuming process. We show here how genetic algorithms can be applied to automatically discover rules governing selfreplicating structures. The main difficulty in this problem lies in the choice of the fitness evaluation technique. The solution we present is based on a multiobjective fitness function consisting of three independent measures: growth in number of components, relative positioning of components, and the multiplicity of replicants. We introduce a new paradigm for cellular automata models with weak rotational symmetry, called orientation insensitive input, and hypothesize that it facilitates discovery of selfreplicating structures by reducing searchspace sizes. Experimental yields of selfreplicating structures discovered using our technique are shown to be statistically significant. The discovered selfreplicating structures compare favorably in terms of simplicity with those generated manually in the past, but differ in unexpected ways. These results suggest that further exploration in the space of possible selfreplicating structures will yield additional new structures. Furthermore, this research sheds light on the process of creating selfreplicating structures, opening the door to future studies on the discovery of novel selfreplicating molecules and selfreplicating assemblers in nanotechnology.
Deducing Local Rules for Solving Global Tasks with Random Boolean Networks
, 2006
"... It has been shown that uniform as well as nonuniform cellular automata (CA) can be evolved to perform certain computational tasks. Random Boolean networks are a generalization of twostate cellular automata, where the interconnection topology and the cell’s rules are specified at random. Here we pr ..."
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Cited by 19 (2 self)
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It has been shown that uniform as well as nonuniform cellular automata (CA) can be evolved to perform certain computational tasks. Random Boolean networks are a generalization of twostate cellular automata, where the interconnection topology and the cell’s rules are specified at random. Here we present a novel analytical approach to find the local rules of random Boolean networks (RBNs) to solve the global density classification and the synchronization task from any initial configuration. We quantitatively and qualitatively compare our results with previously published work on cellular automata and show that randomly interconnected automata are computationally more efficient in solving these two global tasks. Our approach also provides convergence and quality estimates and allows the networks to be randomly rewired during operation, without affecting the global performance. Finally, we show that RBNs outperform smallworld topologies on the density classification task and that they perform equally well on the synchronization task. Our novel approach and the results may have applications in designing robust complex networks and locally interacting distributed computing systems for solving global tasks.
Evolving Asynchronous and Scalable Nonuniform Cellular Automata
 In Proceedings of International Conference on Artificial Neural Networks and Genetic Algorithms (ICANNGA97
, 1997
"... We have previously shown that nonuniform cellular automata (CA) can be evolved to perform computational tasks, using the cellular programming algorithm. In this paper we focus on two novel issues, namely the evolution of asynchronous CAs, and the scalability of our evolved systems. We find that as ..."
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Cited by 15 (3 self)
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We have previously shown that nonuniform cellular automata (CA) can be evolved to perform computational tasks, using the cellular programming algorithm. In this paper we focus on two novel issues, namely the evolution of asynchronous CAs, and the scalability of our evolved systems. We find that asynchrony presents a more difficult case for evolution though good CAs can still be attained. We describe an empiricallyderived scaling procedure by which successful CAs of any size may be obtained from a particular evolved system. Our motivation for this study stems in part by our desire to attain realistic systems that are more amenable to implementation as `evolving ware', evolware. 1 Introduction Cellular automata (CA) are dynamical systems in which space and time are discrete. A cellular automaton consists of an array of cells, each of which can be in one of a finite number of possible states, updated synchronously in discrete time steps according to a local, identical interaction rule...
CoEvolving Architectures for Cellular Machines
, 1996
"... Recent studies have shown that nonuniform cellular automata (CA), where cellular rules need not necessarily be identical, can be coevolved to perform computational tasks. This paper extends these studies by generalizing on a second aspect of CAs, namely their standard, homogeneous connectivity. We ..."
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Cited by 11 (3 self)
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Recent studies have shown that nonuniform cellular automata (CA), where cellular rules need not necessarily be identical, can be coevolved to perform computational tasks. This paper extends these studies by generalizing on a second aspect of CAs, namely their standard, homogeneous connectivity. We study nonstandard architectures, where each cell has a small, identical number of connections, yet not necessarily from its most immediate neighboring cells. We show that such architectures are computationally more efficient than standard architectures in solving global tasks, and also provide the reasoning for this. It is shown that one can successfully evolve nonstandard architectures through a twolevel evolutionary process, in which the cellular rules evolve concomitantly with the cellular connections. Specifically, studying the global density task, we identify the average cellular distance as a prime architectural parameter determining cellular automata performance. We carry out a ...
Spontaneous emergence of selfreplicating structures in molecube automata
 Artificial Life X: Proceedings of the Tenth International Conference on the Simulation and Synthesis of Living Systems
, 2006
"... We propose and implement a discrete, twodimensional evolutionary simulation of large numbers of interacting robotic modules called “molecubes, ” which were shown empirically to have selfreplicating ability (Zykov et al. 2005). In this simulation, the spontaneous and continuous emergence of large n ..."
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Cited by 6 (1 self)
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We propose and implement a discrete, twodimensional evolutionary simulation of large numbers of interacting robotic modules called “molecubes, ” which were shown empirically to have selfreplicating ability (Zykov et al. 2005). In this simulation, the spontaneous and continuous emergence of large numbers of simple selfreplicating molecube structures is observed without any explicit selection for this behavior. A quantitative comparison of structures ’ selfreplicability is investigated using a universal selfreplication metric (Bryant and Lipson 2003), as well as the existence of interacting structure groups. Because of the discrete nature of the simulation and simple interactions, it bears strong resemblance to nonuniform cellular automata (Sipper 1995).
QuasiUniform ComputationUniversal Cellular Automata
, 1995
"... . Cellular automata (CA) are dynamical systems in which space and time are discrete, where each cell obeys the same rule and has a finite number of states. In this paper we study nonuniform CA, i.e. with nonuniform local interaction rules. Our focal point is the issue of universal computation, whi ..."
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Cited by 5 (4 self)
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. Cellular automata (CA) are dynamical systems in which space and time are discrete, where each cell obeys the same rule and has a finite number of states. In this paper we study nonuniform CA, i.e. with nonuniform local interaction rules. Our focal point is the issue of universal computation, which has been proven for uniform automata using complicated designs embedded in cellular space. The computationuniversal system presented here is simpler than previous ones, and is embedded in the minimal possible twodimensional cellular space, namely 2state, 5neighbor (which is insufficient for universal computation in the uniform model). The space studied is quasiuniform, meaning that a small number of rules is used (our final design consists of just two rules which is minimal), distributed such that most of the grid contains one rule except for an infinitely small region which contains the others. We maintain that such automata provide us with a simple, general model for studying Artif...