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Showing papers on "Continuous automaton published in 2002"


Journal ArticleDOI
TL;DR: It is shown that the variation of the model parameters allows to describe different types of behaviour, from regular to panic, in simulations of evacuation processes using a recently introduced cellular automaton model for pedestrian dynamics.
Abstract: We present simulations of evacuation processes using a recently introduced cellular automaton model for pedestrian dynamics. This model applies a bionics approach to describe the interaction between the pedestrians using ideas from chemotaxis. Here we study a rather simple situation, namely the evacuation from a large room with one or two doors. It is shown that the variation of the model parameters allows to describe different types of behaviour, from regular to panic. We find a non-monotonic dependence of the evacuation times on the coupling constants. These times depend on the strength of the herding behaviour, with minimal evacuation times for some intermediate values of the couplings, i.e., a proper combination of herding and use of knowledge about the shortest way to the exit.

858 citations


Patent
Mehryar Mohri1, Mark-Jan Nederhof1
18 Jul 2002
TL;DR: In this article, a context-free grammar is represented by a weighted finite-state transducer, which can be used to efficiently compile that grammar into a weighted automaton that accepts the strings allowed by the grammar with the corresponding weights.
Abstract: A context-free grammar can be represented by a weighted finite-state transducer. This representation can be used to efficiently compile that grammar into a weighted finite-state automaton that accepts the strings allowed by the grammar with the corresponding weights. The rules of a context-free grammar are input. A finite-state automaton is generated from the input rules. Strongly connected components of the finite-state automaton are identified. An automaton is generated for each strongly connected component. A topology that defines a number of states, and that uses active ones of the non-terminal symbols of the context-free grammar as the labels between those states, is defined. The topology is expanded by replacing a transition, and its beginning and end states, with the automaton that includes, as a state, the symbol used as the label on that transition. The topology can be fully expanded or dynamically expanded as required to recognize a particular input string.

171 citations


Journal Article
TL;DR: A necessary and sufficient condition for a one-dimensional q-state n-input cellular automaton rule to be number-conserving is established and two different forms of simpler and more visual representations of these rules are given.
Abstract: A necessary and sufficient condition for a one-dimensional q-state n-input cellular automaton rule to be number-conserving is established Two different forms of simpler and more visual representations of these rules are given, and their flow diagrams are determined Various examples are presented and applications to car traffic are indicated Two nontrivial three-state three-input self-conjugate rules have been found They can be used to model the dynamics of random walkers

100 citations


Journal ArticleDOI
TL;DR: The aim is to establish a theoretical relation between two well-known automata recognizing the language of E, namely the position automaton PE constructed by Glushkov or McNaughton and Yamada, and the equation automaton EE constructed by Mirkin or Antimirov.

98 citations


Book ChapterDOI
08 Jul 2002
TL;DR: A new one-dimensional universal automaton with von Neumann neighborhood and only 6 states is constructed, thus improving the best known lower bound both for computational and intrinsic universality.
Abstract: We formalize the idea of intrinsically universal cellular automata, which is strictly stronger than classical computational universality. Thanks to this uniform notion, we construct a new one-dimensional universal automaton with von Neumann neighborhood and only 6 states, thus improving the best known lower bound both for computational and intrinsic universality.

66 citations


Journal ArticleDOI
TL;DR: It is proved that the identity on grids of size p × q with p > √2q can be decomposed into three parts and the identity of this group if the automaton is defined on rectangular grids is studied.

50 citations


Journal ArticleDOI
TL;DR: This work constructs a three-dimensional self-inspective self-reproducing reversible cellular automaton by extending the two-dimensional version SR8, which canSelf-reproduce various patterns in three- dimensional reversible cellular space without dissipating garbage signals.
Abstract: Due to inevitable power dissipation, it is said that nano-scaled computing devices should perform their computing processes in a reversible manner. This will be a large problem in constructing three-dimensional nano-scaled functional objects. Reversible cellular automata (RCA) are used for modeling physical phenomena such as power dissipation, by studying the dissipation of garbage signals. We construct a three-dimensional self-inspective self-reproducing reversible cellular automaton by extending the two-dimensional version SR8. It can self-reproduce various patterns in three-dimensional reversible cellular space without dissipating garbage signals.

41 citations


Journal ArticleDOI
TL;DR: A novel type of Asynchronous Cellular Automata, in which transitions of cells only take place when triggered by transitions of their neighboring cells, called Self-Timed Cellular Automaton (STCA), which offers control over its cells' operations to the same degree while at the same time offers the flexibility of its purely asynchronous counterparts.

36 citations


Book ChapterDOI
08 Jul 2002
TL;DR: This paper gives in this paper a method to compute a reversible automaton from the minimal automaton of a reversible language that contains an equivalent automaton which is quasi-reversible.
Abstract: Reversible languages occur in many different domains Although the decision for the membership of reversible languages was solved in 1992 by Pin, an effective construction of a reversible automaton for a reversible language was still unknown We give in this paper a method to compute a reversible automaton from the minimal automaton of a reversible language With this intention, we use the universal automaton of the language that can be obtained from the minimal automaton and that contains an equivalent automaton which is quasi-reversible This quasi-reversible automaton has nearly the same properties as a reversible one and can easily be turned into a reversible automaton

35 citations


Journal ArticleDOI
TL;DR: The central theme of the paper is that the cellular automaton paradigm is tantamount to classical block Jacobi or block Gauss‐Seidel iteration, and consequently the performance of a cellular Automaton can be rigorously analyzed and predicted.
Abstract: Traditional parallel methods for structural design, as well as modern preconditioned iterative linear solvers, do not scale well. This paper discusses the application of massively scalable cellular automata (CA) techniques to structural design, specifically trusses. There are two sets of CA rules, one used to propagate stresses and strains, and one to perform design updates. These rules can be applied serially, periodically, or concurrently, and Jacobi or Gauss‐Seidel style updating can be done. These options are compared with respect to convergence, speed, and stability for an example, problem of combined sizing and topology design of truss domain structures. The central theme of the paper is that the cellular automaton paradigm is tantamount to classical block Jacobi or block Gauss‐Seidel iteration, and consequently the performance of a cellular automaton can be rigorously analyzed and predicted.

30 citations


Proceedings ArticleDOI
03 Jul 2002
TL;DR: An on-line algorithm is described building the finite automaton that accepts all common subsequences of the given set of strings.
Abstract: Given a set of strings, a common subsequence of this set is a string that is a subsequence of each string in this set. We describe an on-line algorithm building the finite automaton that accepts all common subsequences of the given set of strings.

Journal Article
TL;DR: The aim is to provide a detailed description of the canonical automaton based on the notions of syntactical rectangle and characteristic event, which appears to be a good representative element in the equivalence class of non-deterministic automata recognizing a given language.
Abstract: We can represent the canonical automaton of a language as the smallest automaton which contains any other automaton recognizing this language, providing equivalent states are merged. Indeed, the canonical automaton appears to be a good representative element in the equivalence class of non-deterministic automata recognizing a given language. Our aim is to provide a detailed description of the canonical automaton based on the notions of syntactical rectangle and characteristic event. In our approach, a state of the canonical automaton of a language L is associated with a rectangle (L,R) ⊆ Σ* × Σ*, which is maximal w.r.t. the property L.R ⊆ L. We explicit the link with other characterizations, like considering a state as a residual intersection which was given by Arnold et al., and the fundamental automaton defined by Matz and Potthoff. In particular, we pretend that the construction of the canonical automaton has the same time complexity as the construction of the fundamental automaton. Our last section briefly discusses the problem of searching minimal NFAs using the canonical automaton.

Journal ArticleDOI
TL;DR: This work suggests it is possible by presenting a systematic approach for creating 1D linear cellular automata that in parallel can locate all starting positions of complete matches to a given PROSITE pattern in a string.

Book ChapterDOI
25 Mar 2002
TL;DR: Enough conditions are studied to ensure that an automaton operating in discrete-time refines a hybrid automaton with its underlying continuous time model, which provides the notion of refinement.
Abstract: Notations like hybrid automata are highly useful in the development process of hybrid systems to document requirements in early design steps. When it comes to implementation a part of the requirements will be realized in software in a discrete-time manner. We therefore study sufficient conditions which ensure that an automaton operating in discrete-time refines a hybrid automaton with its underlying continuous time model. Our notion of refinement provides that vital properties which have been established for the hybrid automaton also hold for its refinement. Furthermore, we outline a method how to derive a discrete-time refinement from a hybrid automaton.

Journal Article
TL;DR: Using symbolic dynamical theory, the temporal evolution orbits of cellular automata are coarse-grain and it is proved that its width 1-evolution language is regular, but for every n " 2 its width n-evolved language is not context free but context sensitive.
Abstract: Cellular automata are classes of mathematical systems characterized by discreteness (in space, time, and state values), determinism, and local interaction. Using symbolic dynamical theory, we coarse-grain the temporal evolution orbits of cellular automata. By means of formal languages and automata theory, we study the evolution complexity of the elementary cellular automaton with local rule number 18 and prove that its width 1-evolution language is regular, but for every n " 2 its width n-evolution language is not context free but context sensitive.

Journal Article
TL;DR: A number-conserving partitioned cellular automaton (NC-PCA) is defined, which is divided into three parts, and each cell is represented by a triple of non-negative integers, and it is shown that Minsky's 3n time solution can be embedded into an NC- PCA, having an integer at most 9 in each part of a cell.
Abstract: We study the Firing Squad Synchronization Problem (FSSP) on a cellular automaton (CA) having number-conservation property In a number-conserving CA, all states of cells are represented by (tuples of) non-negative integers and the total number of its configuration is conserved throughout its computing processes But, if we use a usual framework of CA in which each state of a cell is represented by a single integer, it is not possible to make every cell to be in the same firing state, which should be different from the soldier state, under the usual FSSP condition without violating the number-conservativeness So, we employ the framework of a partitioned cellular automaton, and define a number-conserving partitioned cellular automaton (NC-PCA) Its cell is divided into three parts, and hence each cell is represented by a triple of non-negative integers In NC-PCA, only the constraint that the local transition function should satisfy a number-conserving condition is supposed Thus, it makes relatively easy to construct an NC-PCA Because each cell can hold three non-negative integers, it is possible to represent different states even if the sum of three numbers are equal Using this technique, we show that Minsky's 3n time solution can be embedded into an NC-PCA, having an integer at most 9 in each part of a cell

Journal ArticleDOI
TL;DR: A simplified cellular model for computer network, namely the NaSch network model, is proposed, which is originated at the Na Sch model of road traffic and consists of two kinds of cells, i.e. node cell and link cell.

Journal ArticleDOI
01 May 2002
TL;DR: A fine-grained parallel model for simulating reaction--diffusion processes and a "hybrid" (CA + CNN) approach is assumed to improve computational stability relative to round off errors and to simplify allocation of the task onto several processors.
Abstract: A fine-grained parallel model for simulating reaction--diffusion processes is proposed. The model combines cellular automaton (CA) computation of a diffusion part, and cellular neural network (CNN) approximation of a reaction part. The simulation algorithm is iterative. At each step each cell of the array executes CA diffusion rules and computes a neural function which updates the array according to the reaction part value. Both operations are probabilistic. The model is intended to be used for simulation reaction--diffusion if a partial differential equation (PDE) of the phenomenon is given. Such a "hybrid" (CA + CNN) approach is assumed to improve computational stability relative to round off errors and to simplify allocation of the task onto several processors.

Book ChapterDOI
15 Aug 2002
TL;DR: The presented model of self-assembling finite automata is a natural and unified generalization of regular and context-free languages since degrees one and two are characterizing the finite and pushdown automata, respectively.
Abstract: We investigate a model of self-assembling finite automata. An automaton is assembled on demand during its computation from copies out of a finite set of items. The items are pieces of a finite automaton which are connected to the already existing automaton by overlaying states. Depending on the allowed number of such interface states, the degree, infinite hierarchies of properly included language families are shown. The presented model is a natural and unified generalization of regular and context-free languages since degrees one and two are characterizing the finite and pushdown automata, respectively. Moreover, by means of different closure properties nondeterministic and deterministic language families are separated.

Journal ArticleDOI
TL;DR: A three-state, stochastic cellular automaton that runs on Penrose tilings and seems to evolve to a three-colored equilibrium is presented.

Journal Article
TL;DR: In this article, a general methodology is developed to compute the solution of a wide variety of basic counting problems in a uniform way: (1) the objects to be counted are enumerated by means of an infinite weighted automaton; (2) the automaton is reduced by the quantitative notion of stream bisimulation; and (3) the reduced automaton was used to compute an expression (in terms of stream constants and operators) that represents the stream of all counts.
Abstract: A general methodology is developed to compute the solution of a wide variety of basic counting problems in a uniform way: (1) the objects to be counted are enumerated by means of an infinite weighted automaton; (2) the automaton is reduced by means of the quantitative notion of stream bisimulation; (3) the reduced automaton is used to compute an expression (in terms of stream constants and operators) that represents the stream of all counts.

Book ChapterDOI
18 Sep 2002
TL;DR: It is shown that an infinite prime sequence can be generated in real-time by a cellular automaton having 1-bit inter-cell communications.
Abstract: It is shown that an infinite prime sequence can be generated in real-time by a cellular automaton having 1-bit inter-cell communications.

Journal ArticleDOI
TL;DR: The elementary cellular automaton of rule 22 is studied by the tools of formal language theory and symbolic dynamics and it is proved that for every n≥2 its width n-evolution language is not regular.
Abstract: Cellular automata are the discrete dynamical systems of simple construction but with complex and varied behaviors. In this paper, the elementary cellular automaton of rule 22 is studied by the tools of formal language theory and symbolic dynamics. Its temporal evolution orbits are coarse-grained into evolution sequences and the evolution languages are defined. It is proved that for every n≥2 its width n-evolution language is not regular.

Book ChapterDOI
27 Jun 2002
TL;DR: This paper develops a series of learning algorithms for well-known classes of regular languages as instantiations of the same master algorithm, e.g., the learning by rote approach of minimizing the number of states in the automaton and inference of k-reversible languages.
Abstract: Regular language learning from positive examples alone is infeasible Subclasses of regular languages, though, can be inferred from positive examples only The most common approach for learning such is the specific-to-general technique of merging together either states of an initial finite state automaton or nonterminals in a regular grammar until convergenceIn this paper we seek to unify some language learning approaches under the general-to-specific learning scheme In automata terms it is implemented by refining the partition of the states of the automaton starting from one block until desired decomposition is obtained; ie, until all blocks in the partition are uniform according to the predicate determining the properties required from the languageWe develop a series of learning algorithms for well-known classes of regular languages as instantiations of the same master algorithm Through block decomposition we are able to describe in the same scheme, eg, the learning by rote approach of minimizing the number of states in the automaton and inference of k-reversible languagesUnder the worst-case analysis partition-refinement is less efficient than alternative approaches However, for many cases it turns out more efficient in practice Moreover, it ensures the inference of the canonical automaton, whereas the state-merging approach will leave excessive states to the final automaton without a separate minimization step

Book ChapterDOI
03 Apr 2002
TL;DR: In this paper, the authors investigate how increasing the dimension of the array can help to draw signals on cellular automata and show the existence of a gap of constructible signals in any dimension.
Abstract: We investigate how increasing the dimension of the array can help to draw signals on cellular automata. We show the existence of a gap of constructible signals in any dimension. We exhibit two cellular automata in dimension 2 to show that increasing the dimension allows to reduce the number of states required for some constructions.

Journal ArticleDOI
TL;DR: This paper obtains some properties for the basis automaton, which is, like automaton of canonical form, an invariant of a given regular language in a non-deterministic finite Rabin-Scott's automata.
Abstract: In this paper we consider non-deterministic finite Rabin-Scott's automata. We obtain some properties for the basis automaton, which is, like automaton of canonical form, an invariant of a given regular language. We obtain also a new algorithm of constructing the basis automaton for a given regular language.

Journal ArticleDOI
TL;DR: The study on the opacity of a finite automaton is studied to characterize opaque automata and find out if its opacity is maximal.

Journal ArticleDOI
TL;DR: A finite-state automaton model of membrane activity is developed, which will potentially permit the evaluation and comparison of large numbers of simulated 3-dimensional networks and was found to be capable of modelling the most important characteristics of neural membranes.

Journal Article
TL;DR: This paper concerns searching substrings in a string using the factor automaton, a deterministic finite automaton constructed to accept every substring of the given string.
Abstract: This paper concerns searching substrings in a string using the factor automaton The factor automaton is a deterministic finite automaton constructed to accept every substring of the given string Nondeterministic factor automaton is used to achieve new operations on factor automata for searching in non-constant texts

Journal Article
TL;DR: In this paper the notions of fuzzy minimal automaton and reduced fuzzy automaton are introduced, the relationship among fuzzy minimal Automaton, rational fuzzy language and reduced fuzzier language are discussed and several important results are obtained.
Abstract: In this paper the notions of fuzzy minimal automaton and reduced fuzzy automaton are introduced, the relationship among fuzzy minimal automaton, rational fuzzy language and reduced fuzzy automaton are discussed, several important results are obtained.