Papers by Keyword: Cellular Automata (CA)

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Authors: Liang Yu, Liu Shun Wu, Liao Sha Li, Yuan Chi Dong
Abstract: Dendrite structure in solidification process has been studied by many researchers for it’s widely existence. In present work, a cellular automata model was proposed according to the basic physical chemistry concepts, which was helpful for a better understanding of the dendrite crystal growth and its physical chemistry mechanism. Two kinds of structures were considered in the model: hexagonal and rectangle. The status of every site was set as 0 and 1 which represent non-solidified and solidified state. Temperature field was simulated using finite difference method on the same mesh. The states of sites were changed according to the overcooling condition only. The computer simulation results showed that dendrite structure could be obtained under overcooling condition and temperature field calculation only, the structure of the dendrite was decided by the geometry of the model. The simulation resulted similar pattern as that obtained by experimental observation. The present model suggested that there exist a very simple basic for the typical complex phenomena, dendrite structure.
Authors: Xiao Wang
Abstract: In order to fill the blank of the conventional bus routes and to provide a door-to-door transportation service, community bus is a new mode to connect the last mile of public transportation. This paper built a cellular automata model of opening boundary conditions based on the community bus route to explore that the running rules of community bus. Through numerical simulations using departure time interval and passenger arrival rate as index, phase diagrams are obtained and characteristics are found.
Authors: Jia Tai Gang, Peng Yan Shi, San Shan Gang
Abstract: A cellular automata model with inhomogeneity and mobility was presented. The inhomogeneity in individuals’ behaviors was considered by assigning the distance on their neighbors, varying levels of infectivity and susceptibility. The individual mobility was reflected by random walk cellular automata. The proposed model can serve as a basis to simulate influenza A (H1N1) based on real data. We studied the effect of two population movement parameters on the epidemic propagation: the percentage and the max-distance of population movement. The results show that the epidemic spreading is more sensitive to the former. The infected individuals are positive growth while the percentage of population movement increases. And the number of infected individual eventually stabilizes in the case of plotting the relation of the max-distance against the infected.
Authors: S. Das, M.F. Abbod, Q. Zhu, Eric J. Palmiere, I.C. Howard, D.A. Linkens, C.M. Sellars
Abstract: This paper presents a modelling strategy that combines neuro-fuzzy methods to dene the material model with cellular automata representations of the microstructure, all embedded within a nite element solver that can deal with the large deformations of metal processing technology. We use the acronym nf-CAFE as a label for the method. The need for such an approach arises from the twin demands of computational speed for quick solutions for ecient material characterisation by incorporating metallurgical knowledge for material design models and subsequent process control. In this strategy, the cellular automata hold the microstructural features in terms of sub-grain size and dislocation density which are modelled by a neuro-fuzzy system that predicts the ow stress. The proposed methodology is validated on a two dimensional (2D) plane strain compression nite element simulation with Al1%Mg alloy. Results from the simulations show the potential of the model for incorporating the eects of the underlying microstructure on the evolving ow stress elds. In doing this, the paper highlights the importance of understanding the local transition rules that aect the global behaviour during deformation.
Authors: Da Lin Zhu, Teng Zhan, Rui Tang, Hui Fang Li
Abstract: Since the individuals’ reproduction and existing probability can be greatly improved by introducing evolution rule into cellular automata algorithm, this paper presents a new niche cellular genetic algorithm by involving cellular automata evolution rule and introducing niche technique. The results of simulation experiments on some well-known complex benchmarking problems reveal that this algorithm outperforms the basic cellular genetic algorithms (cGAs) and cGAs with evolution rule in terms of diversity, convergence, global optimization and stability.
Authors: Jun Hu, Lei You, Juan Wei, Wen Qian Wu, Di Zhou, Ying Liang
Abstract: In order to effectively reduce evacuation time of pedestrians in emergencies, a novel evacuation model is proposed based on the three-dimensional cellular automation. The model, according to Moore cellular structure, firstly defines location income and estimates evacuation time parameter, and then gives calculation formula for moving probability of pedestrians at next moment. Meanwhile, in combination with the degree of fear and moving speed, evacuation strategies and cellular evolution rules suited to the three-dimensional condition are raised. At last, by establishing simulation model, the article profoundly analyses key factors that affect evacuation time of pedestrians, and finds that the evacuation time shows a negative correlation with the exit width, but a positive correlation with pedestrian density. Appropriate increase of pedestrians fear degree is good for reducing the whole evacuation time.
Authors: Hong Tang, Yun Sheng Ge, Xiao Hai Pan, Shu Feng We
Abstract: In order to overcome the drawbacks of Simple Genetic Algorithm such as cannot get the most optimal result, low convergence speed et al. Cellular Simple Genetic Algorithm-a new genetic algorithm based on Cellular Automata-is presented in this paper. Compared with the Simple Genetic Algorithm, the experiment results show the Cellular Simple Genetic Algorithm has remarkable advantages in following aspects: reducing the search-time and improving the precise of target function.
Authors: Guang Yu Tan, Guang Jun Liu, G.H. Li, H. Song, Yi Ming Rong
Abstract: This paper presents a self-organizing method for reconstruction of complex groove of milling insert. The local rule of Cellular Automata is proposed to design and optimize the groove of milling insert. The states of cells are modified according to the local rule applied. The state of the entire system is updated based on the state of the cell and its neighboring cell, and these cells’ states define the state of the entire domain, and the groove can be reconstructed. The reconstructed groove is tested by a FEM simulation. The simulation results show that the reconstructed groove has a satisfied performance on the stress field and temperature field.
Authors: Xiao Jing Meng, Jiang Ping Zhao
Abstract: Post-earthquake fire is disaster which causes great harm to human. In this paper, post-earthquake fire risk assessment of urban area was analyzed, and a fire spreading probability model of urban area based on cellular automata was developed. The fire spreading process has been reproduced successfully by our model. The reproduction of fire process not only improves people’s cognition, but also provides the guide for city planning
Authors: Krzysztof Nowak
Abstract: Polycrystalline materials like metals fail in creep conditions due to development of inter- or intra-granular voids. The model of creep damage is proposed which simulates voids growth on microscale using Cellular Automata (CA) technique at RVE level, coupled with creep deformation on macroscale. It is assumed that experimentally observed creep deformation is a result of interaction between hardening and softening of a material. The softening process is mainly due to voids development and it is built in deformation model by weakening of effective stress by damage parameter calculated by CA part of the model. Parameters of model are based on primary and secondary stages of creep experiments. The results of simulations show that multiscale model predicts quite well times to failure and strains at failure.
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