Simulation of Dynamic Recrystallization Using Cellular Automaton Method
Institute of Scientific and Technical Information of China (English)
XIAO Hong; XIE Hong-biao; YAN Yan-hong; Jun YANAGIMOTO
2004-01-01
A new modeling approach that couples fundamental metallurgical principles of dynamical recrystallization with the cellular automaton method was developed to simulate the microstructural evolution linking with the plastic flow behavior during thermomechanical processing. The driving force for the nucleation and growth of dynamically recrystallized grain is the volume free energy due to the stored dislocation density of a deformation matrix. The growth terminates the impingement. The model is capable of simulating kinetics, microstructure and texture evolution during recrystallization. The predictions of microstructural evolution agree with the experimental results.
A cellular automaton framework for infectious disease spread simulation.
Pfeifer, Bernhard; Kugler, Karl; Tejada, Maria M; Baumgartner, Christian; Seger, Michael; Osl, Melanie; Netzer, Michael; Handler, Michael; Dander, Andreas; Wurz, Manfred; Graber, Armin; Tilg, Bernhard
2008-01-01
In this paper, a cellular automaton framework for processing the spatiotemporal spread of infectious diseases is presented. The developed environment simulates and visualizes how infectious diseases might spread, and hence provides a powerful instrument for health care organizations to generate disease prevention and contingency plans. In this study, the outbreak of an avian flu like virus was modeled in the state of Tyrol, and various scenarios such as quarantine, effect of different medications on viral spread and changes of social behavior were simulated.The proposed framework is implemented using the programming language Java. The set up of the simulation environment requires specification of the disease parameters and the geographical information using a population density colored map, enriched with demographic data.The results of the numerical simulations and the analysis of the computed parameters will be used to get a deeper understanding of how the disease spreading mechanisms work, and how to protect the population from contracting the disease. Strategies for optimization of medical treatment and vaccination regimens will also be investigated using our cellular automaton framework.In this study, six different scenarios were simulated. It showed that geographical barriers may help to slow down the spread of an infectious disease, however, when an aggressive and deadly communicable disease spreads, only quarantine and controlled medical treatment are able to stop the outbreak, if at all.
Cellular Automaton Simulation of Evacuation Process in Story
Institute of Scientific and Technical Information of China (English)
MA Chang-Qun; ZHENG Rong-Sen; GAO Chun-Yuan; QIU Bing; DENG Min-Yi; KONC Ling-Jiang; LIU Mu-Ren
2008-01-01
Computer simulations on the evacuation process in a story are launched with cellular automaton in this article. The story is composed of five rooms and one corridor. Influence of various parameters on the evacuation process is investigated. It shows that the width of the door of rooms has little influence but the width of the corridor and themaximum velocity of the pedestrian have great influence on the time for evacuation. The relation between evacuation time and the width of corridor is found as tc ∝ W-.0.84. It is also found that appropriate shape of the room is helpful to evacuation.
Simulation of plant communities with a cellular automaton
Energy Technology Data Exchange (ETDEWEB)
Gassmann, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1999-08-01
With a modelling approach based on cellular automata, five observed types of plant development can be simulated. In addition, the proposed model shows a strong tendency towards the formation of patches and a high degree of dynamical and structural instability leading to limits of predictability for the asymptotic solution chosen by the system among several possible metastable patterns (multistability). Further, external fluctuations can be shown to have advantages for certain plant types. The presented model unifies the fundamental dichotomy in vegetation dynamics between determinism (understood as predictability) and disorder (chance effects) by showing the outcome of both classical theories as special cases. (author) 2 figs., 4 refs.
Simulation of Magnesium Alloy AZ91D Microstructure Using Modified Cellular Automaton Method
Institute of Scientific and Technical Information of China (English)
HUO Liang; LI Bin; SHI Yufeng; XU Qingyan; HAN Zhiqiang; LIU Baicheng
2009-01-01
A two-dimensional modified cellular automaton model was developed to simulate the solidification process of magnesium alloy, The stochastic nucleation, solute redistribution, and growth anisotropy effects were taken into account in the present model. The model was used to simulate the grain size of magnesium alloy AZ91D for various cooling rates during the solidification process. To quantitatively validate the current model, metallographic expedments were carded out on specimens obtained from sand mold AZ91D step castings. The metallographic results agree well with the prediction results. The current model can be used to accurately predict the grain sizes of cast AZ91D magnesium alloy.
Cellular Automaton Simulation For Volume Changes Of Solidifying Nodular Cast Iron
Directory of Open Access Journals (Sweden)
Burbelko A.
2015-09-01
Full Text Available Volume changes of the binary Fe-C alloy with nodular graphite were forecast by means of the Cellular Automaton Finite Differences (CA-FD model of solidification. Simulations were performed in 2D space for differing carbon content. Dependences of phase density on temperature were considered in the computations; additionally density of the liquid phase and austenite were deemed as a function of carbon concentration. Changes of the specific volume were forecast on the base of the phase volume fractions and changes of phase density. Density of modeled material was calculated as weighted average of densities of each phase.
A three-dimensional cellular automaton model for simulation of dendritic growth of magnesium alloy
Institute of Scientific and Technical Information of China (English)
Mengwu WU; Shoumei XIONG
2012-01-01
A numerical model based on the cellular automaton method for the three-dimensional simulation of dendritic growth of magnesium alloy was developed.The growth kinetics was calculated from the complete solution of the transport equations.By constructing a three-dimensional anisotropy model with the cubic CA cells,simulation of dendritic growth of magnesium alloy with six-fold symmetry in the basal plane was achieved.The model was applied to simulate the equiaxed dendritic growth and columnar dendritic growth under directional solidification,and its capability was addressed by comparing the simulated results to experimental results and those in the previously published works.Meanwhile,the three-dimensional simulated results were also compared with that of in two dimensions,offering a deep insight into the microstructure formation of magnesium alloy during solidification.
Simulation of emotional contagion using modified SIR model: A cellular automaton approach
Fu, Libi; Song, Weiguo; Lv, Wei; Lo, Siuming
2014-07-01
Emotion plays an important role in the decision-making of individuals in some emergency situations. The contagion of emotion may induce either normal or abnormal consolidated crowd behavior. This paper aims to simulate the dynamics of emotional contagion among crowds by modifying the epidemiological SIR model to a cellular automaton approach. This new cellular automaton model, entitled the “CA-SIRS model”, captures the dynamic process ‘susceptible-infected-recovered-susceptible', which is based on SIRS contagion in epidemiological theory. Moreover, in this new model, the process is integrated with individual movement. The simulation results of this model show that multiple waves and dynamical stability around a mean value will appear during emotion spreading. It was found that the proportion of initial infected individuals had little influence on the final stable proportion of infected population in a given system, and that infection frequency increased with an increase in the average crowd density. Our results further suggest that individual movement accelerates the spread speed of emotion and increases the stable proportion of infected population. Furthermore, decreasing the duration of an infection and the probability of reinfection can markedly reduce the number of infected individuals. It is hoped that this study will be helpful in crowd management and evacuation organization.
Mesoscale simulation of discontinuous dynamic recrystallization using the cellular automaton method
Institute of Scientific and Technical Information of China (English)
Baojun YU; Xiaojun GUAN; Lijun WANG; Qingkai ZENG; Qianqian LIU; Yu CAO
2011-01-01
A dynamic recrystallization (DRX) cellular automaton (CA) model that can mark the microstructure with DRX circle was developed.The effects of initial grain size on the stress-strain curve,mean grain size and DRX fraction were mainly investigated,and the simulated results were compared with those obtained from previous researches.The results show that the shape of the stress-strain curve is sensitive,while the stress and mean grain size at the steady state are insensitive to the initial grain size.The transition from a multiple-peak stress-strain curve to a single-peak one can be explained by variations in DRX circle fraction,and the initial grain size to make this transition is between 70 and 80 μm.
Institute of Scientific and Technical Information of China (English)
2012-01-01
A cellular automaton （CA）-finite element （FE） model and a phase field （PF）-FE model were used to simulate equiaxed dendritic growth during the solidification of hexagonal metals. In the CA-FE model, the conservation equations of mass and energy were solved in order to calculate the temperature field, solute concentration, and the dendritic growth morphology. CA-FE simulation results showed reasonable agreement with the previously reported experimental data on secondary dendrite arm spacing （SDAS） vs cooling rate. In the PF model, a PF variable was used to distinguish solid and liquid phases similar to the conventional PF models for solidification of pure materials. Another PF variable was considered to determine the evolution of solute concentration. Validation of both models was performed by comparing the simulation results with the analytical model developed by Lipton-Glicksman-Kurz （LGK）, showing quantitatively good agreement in the tip growth velocity at a given melt undercooling. Application to magnesium alloy AZ91 （approximated with the binary Mg-8.9 wt% AI） illustrates the difficulty of modeling dendrite growth in hexagonal systems using CA-FE regarding mesh-induced anisotropy and a better performance of PF-FE in modeling multiple arbitrarily-oriented dendrites growth.
Akbari, Mostafa; Asadi, Parviz; Besharati Givi, MohammadKazem; Zolghadr, Parisa
2016-03-01
To predict the grain size and microstructure evolution during friction stir welding (FSW) of AZ91 magnesium alloy, a finite element model (FEM) is developed based on the combination of a cellular automaton model and the Kocks - Mecking and Laasraoui-Jonas models. First, according to the flow stress curves and using the Kocks - Mecking model, the hardening and recovery parameters and the strain rate sensitivity were calculated. Next, an FEM model was established in Deform-3D software to simulate the FSW of AZ91 magnesium alloy. The results of the FEM model are used in microstructure evolution models to predict the grain size and microstructure of the weld zone. There is a good agreement between the simulated and experimental microstructures, and the proposed model can simulate the dynamic recrystallization (DRX) process during FSW of AZ91 alloy. Moreover, microstructural properties of different points in the SZ as well as the effect of the w/v parameter on the grain size and microstructure are considered.
Simulation of Microstructure during Laser Rapid Forming Solidification Based on Cellular Automaton
Directory of Open Access Journals (Sweden)
Zhi-jian Wang
2014-01-01
Full Text Available The grain microstructure of molten pool during the solidification of TC4 titanium alloy in the single point laser cladding was investigated based on the CAFE model which is the cellular automaton (CA coupled with the finite element (FE method. The correct temperature field is the prerequisite for simulating the grain microstructure during the solidification of the molten pool. The model solves the energy equation by the FE method to simulate the temperature distribution in the molten pool of the single point laser cladding. Based on the temperature field, the solidification microstructure of the molten pool is also simulated with the CAFE method. The results show that the maximum temperature in the molten pool increases with the laser power and the scanning rate. The laser power has a larger influence on the temperature distribution of the molten pool than the scanning rate. During the solidification of the molten pool, the heat at the bottom of the molten pool transfers faster than that at the top of the molten pool. The grains rapidly grow into the molten pool, and then the columnar crystals are formed. This study has a very important significance for improving the quality of the structure parts manufactured through the laser cladding forming.
A Modified Sensitive Driving Cellular Automaton Model
Institute of Scientific and Technical Information of China (English)
GE Hong-Xia; DAI Shi-Qiang; DONG Li-Yun; LEI Li
2005-01-01
A modified cellular automaton model for traffic flow on highway is proposed with a novel concept about the variable security gap. The concept is first introduced into the original Nagel-Schreckenberg model, which is called the non-sensitive driving cellular automaton model. And then it is incorporated with a sensitive driving NaSch model,in which the randomization brake is arranged before the deterministic deceleration. A parameter related to the variable security gap is determined through simulation. Comparison of the simulation results indicates that the variable security gap has different influence on the two models. The fundamental diagram obtained by simulation with the modified sensitive driving NaSch model shows that the maximumflow are in good agreement with the observed data, indicating that the presented model is more reasonable and realistic.
Recurrence time statistics of landslide events simulated by a cellular automaton model
Piegari, Ester; Di Maio, Rosa; Avella, Adolfo
2014-05-01
The recurrence time statistics of a cellular automaton modelling landslide events is analyzed by performing a numerical analysis in the parameter space and estimating Fano factor behaviors. The model is an extended version of the OFC model, which is a paradigm for SOC in non-conserved systems, but it works differently from the original OFC model as a finite value of the driving rate is applied. By driving the system to instability with different rates, the model exhibits a smooth transition from a correlated to an uncorrelated regime as the effect of a change in predominant mechanisms to propagate instability. If the rate at which instability is approached is small, chain processes dominate the landslide dynamics, and power laws govern probability distributions. However, the power-law regime typical of SOC-like systems is found in a range of return intervals that becomes shorter and shorter by increasing the values of the driving rates. Indeed, if the rates at which instability is approached are large, domino processes are no longer active in propagating instability, and large events simply occur because a large number of cells simultaneously reach instability. Such a gradual loss of the effectiveness of the chain propagation mechanism causes the system gradually enter to an uncorrelated regime where recurrence time distributions are characterized by Weibull behaviors. Simulation results are qualitatively compared with those from a recent analysis performed by Witt et al.(Earth Surf. Process. Landforms, 35, 1138, 2010) for the first complete databases of landslide occurrences over a period as large as fifty years. From the comparison with the extensive landslide data set, the numerical analysis suggests that statistics of such landslide data seem to be described by a crossover region between a correlated regime and an uncorrelated regime, where recurrence time distributions are characterized by power-law and Weibull behaviors for short and long return times
Indian Academy of Sciences (India)
M R Varma; R Sasikumar; S G K Pillai; P K Nair
2001-06-01
A two-dimensional diffusion based model is developed to describe transformation of austenite into ferrite and pearlite under continuous cooling conditions. The nucleation of ferrite is assumed to occur over grain boundaries and the nucleation of pearlite is assumed to be taking place all over the grain and at growing ferrite–austenite interfaces, when the composition and temperature conditions are favourable. A cellular automaton algorithm, with transformation rules based on this model is used for the growth of ferrite and pearlite. Model predicted results for continuous cooling transformations are verified by comparing the model predicted microstructure features with the experimental measurements for two sets of plain carbon steels of different composition and austenite grain size. Using the model, it is possible to generate results like undercooling to start ferrite and pearlite transformations, which are difficult to obtain experimentally.
Cellular Automaton Modeling of Pattern Formation
Boerlijst, M.C.
2006-01-01
Book review Andreas Deutsch and Sabine Dormann, Cellular Automaton Modeling of Biological Pattern Formation, Characterization, Applications, and Analysis, Birkhäuser (2005) ISBN 0-8176-4281-1 331pp..
A Real Space Cellular Automaton Laboratory
Rozier, O.; Narteau, C.
2013-12-01
Investigations in geomorphology may benefit from computer modelling approaches that rely entirely on self-organization principles. In the vast majority of numerical models, instead, points in space are characterised by a variety of physical variables (e.g. sediment transport rate, velocity, temperature) recalculated over time according to some predetermined set of laws. However, there is not always a satisfactory theoretical framework from which we can quantify the overall dynamics of the system. For these reasons, we prefer to concentrate on interaction patterns using a basic cellular automaton modelling framework, the Real Space Cellular Automaton Laboratory (ReSCAL), a powerful and versatile generator of 3D stochastic models. The objective of this software suite released under a GNU license is to develop interdisciplinary research collaboration to investigate the dynamics of complex systems. The models in ReSCAL are essentially constructed from a small number of discrete states distributed on a cellular grid. An elementary cell is a real-space representation of the physical environment and pairs of nearest neighbour cells are called doublets. Each individual physical process is associated with a set of doublet transitions and characteristic transition rates. Using a modular approach, we can simulate and combine a wide range of physical, chemical and/or anthropological processes. Here, we present different ingredients of ReSCAL leading to applications in geomorphology: dune morphodynamics and landscape evolution. We also discuss how ReSCAL can be applied and developed across many disciplines in natural and human sciences.
A cellular automaton evacuation model based on mobile robot's behaviors
Institute of Scientific and Technical Information of China (English)
WENG WenGuo; YUAN HongYong; FAN WeiCheng
2007-01-01
The research of evacuation in some emergencies, e.g. fire, is of great benefit to reducing the injuries of persons. In this paper, a cellular automaton evacuation model based on mobile robot's behaviors is presented. Each person is treated as an intelligent mobile robot, and motor schemas, including move-to-goal, avoid-obstacle, swirl-obstacle and nervous-motion, drive persons to interact with their environment. The motor schemas are combined with cellular automaton theory, and an evacuation model is built. Evacuation simulation of persons with different move velocities shows that the presented model can predict accurately the evacuation phenomena in some emergencies.
Jin, Cheng-Jie; Wang, Wei; Jiang, Rui
2016-08-01
The proper setting of traffic signals at signalized intersections is one of the most important tasks in traffic control and management. This paper has evaluated the four-phase traffic signal plans at a four-leg intersection via cellular automaton simulations. Each leg consists of three lanes, an exclusive left-turn lane, a through lane, and a through/right-turn lane. For a comparison, we also evaluate the two-phase signal plan. The diagram of the intersection states in the space of inflow rate versus turning ratio has been presented, which exhibits four regions: In region I/II/III, congestion will propagate upstream and laterally and result in queue spillover with both signal plans/two-phase signal plan/four-phase signal plan, respectively. Therefore, neither signal plan works in region I, and only the four-phase signal plan/two-phase signal plan works in region II/III. In region IV, both signal plans work, but two-phase signal plan performs better in terms of average delays of vehicles. Finally, we study the diagram of the intersection states and average delays in the asymmetrical configurations.
A cellular automaton model adapted to sandboxes to simulate the transport of solutes
Lora, Boris; Donado, Leonardo; Castro, Eduardo; Bayuelo, Alfredo
2016-04-01
The increasingly use of groundwater sources for human consumption and the growth of the levels of these hydric sources contamination make imperative to reach a deeper understanding how the contaminants are transported by the water, in particular through a heterogeneous porous medium. Accordingly, the present research aims to design a model, which simulates the transport of solutes through a heterogeneous porous medium, using cellular automata. Cellular automata (CA) are a class of spatially (pixels) and temporally discrete mathematical systems characterized by local interaction (neighborhoods). The pixel size and the CA neighborhood were determined in order to reproduce accurately the solute behavior (Ilachinski, 2001). For the design and corresponding validation of the CA model were developed different conservative tracer tests using a sandbox packed heterogeneously with a coarse sand (size # 20 grain diameter 0,85 to 0,6 mm) and clay. We use Uranine and a saline solution with NaCl as a tracer which were measured taking snapshots each 20 seconds. A calibration curve (pixel intensity Vs Concentration) was used to obtain concentration maps. The sandbox was constructed of acrylic (caliber 0,8 cms) with 70 x 45 x 4 cms of dimensions. The "sandbox" had a grid of 35 transversal holes with a diameter of 4 mm each and an uniform separation from one to another of 10 cms. To validate the CA-model it was used a metric consisting in rating the number of correctly predicted pixels over the total per image throughout the entire test run. The CA-model shows that calibrations of pixels and neighborhoods allow reaching results over the 60 % of correctly predictions usually. This makes possible to think that the application of the CA- model could be useful in further researches regarding the transport of contaminants in hydrogeology.
A Computation in a Cellular Automaton Collider Rule 110
Martinez, Genaro J; McIntosh, Harold V
2016-01-01
A cellular automaton collider is a finite state machine build of rings of one-dimensional cellular automata. We show how a computation can be performed on the collider by exploiting interactions between gliders (particles, localisations). The constructions proposed are based on universality of elementary cellular automaton rule 110, cyclic tag systems, supercolliders, and computing on rings.
A Modified Cellular Automaton Model for Traffic Flow
Institute of Scientific and Technical Information of China (English)
葛红霞; 董力耘; 雷丽; 戴世强
2004-01-01
A modified cellular automaton model for traffic flow was proposed. A novel concept about the changeable security gap was introduced and a parameter related to the variable security gap was determined. The fundamental diagram obtained by simulation shows that the maximum flow more approaches to the observed data than that of the NaSch model, indicating that the presented model is more reasonable and realistic.
The Algorithm of Continuous Optimization Based on the Modified Cellular Automaton
Directory of Open Access Journals (Sweden)
Oleg Evsutin
2016-08-01
Full Text Available This article is devoted to the application of the cellular automata mathematical apparatus to the problem of continuous optimization. The cellular automaton with an objective function is introduced as a new modification of the classic cellular automaton. The algorithm of continuous optimization, which is based on dynamics of the cellular automaton having the property of geometric symmetry, is obtained. The results of the simulation experiments with the obtained algorithm on standard test functions are provided, and a comparison between the analogs is shown.
Fire Spread Model for Old Towns Based on Cellular Automaton
Institute of Scientific and Technical Information of China (English)
GAO Nan; WENG Wenguo; MA Wei; NI Shunjiang; HUANG Quanyi; YUAN Hongyong
2008-01-01
Old towns like Lijiang have enormous historic,artistic,and architectural value.The buildings in such old towns are usually made of highly combustible materials,such as wood and grass.If a fire breaks out,it will spread to multiple buildings,so fire spreading and controlling in old towns need to be studied.This paper presents a fire spread model for old towns based on cellular automaton.The cellular automaton rules were set according to historical fire data in empirical formulas.The model also considered the effects of climate.The simulation results were visualized in a geography information system.An example of a fire spread in Lijiang was investigated with the results showing that this model provides a realistic tool for predicting fire spread in old towns.Fire brigades can use this tool to predict when and how a fire spreads to minimize the losses.
A Simple n-Dimensional Intrinsically Universal Quantum Cellular Automaton
Arrighi, Pablo
2010-01-01
We describe a simple n-dimensional quantum cellular automaton (QCA) capable of simulating all others, in that the initial configuration and the forward evolution of any n-dimensional QCA can be encoded within the initial configuration of the intrinsically universal QCA. Several steps of the intrinsically universal QCA then correspond to one step of the simulated QCA. The simulation preserves the topology in the sense that each cell of the simulated QCA is encoded as a group of adjacent cells in the universal QCA.
Exactly solvable cellular automaton traffic jam model.
Kearney, Michael J
2006-12-01
A detailed study is undertaken of the v{max}=1 limit of the cellular automaton traffic model proposed by Nagel and Paczuski [Phys. Rev. E 51, 2909 (1995)]. The model allows one to analyze the behavior of a traffic jam initiated in an otherwise freely flowing stream of traffic. By mapping onto a discrete-time queueing system, itself related to various problems encountered in lattice combinatorics, exact results are presented in relation to the jam lifetime, the maximum jam length, and the jam mass (the space-time cluster size or integrated vehicle waiting time), both in terms of the critical and the off-critical behavior. This sets existing scaling results in their natural context and also provides several other interesting results in addition.
Energy Technology Data Exchange (ETDEWEB)
Saiz, A. [Department of Applied Mathematics, Polytechnic University of Valencia, ETSGE School, Camino de Vera s/n, 46022 Valencia (Spain); Urchueguia, J.F. [Department of Applied Physics, Polytechnic University of Valencia, ETSII School, Camino de Vera s/n, 46022 Valencia (Spain); Martos, J. [Superior Technical School of Engineering, Department of Electronic Engineering, University of Valencia, Vicente Andres Estelles s/n, Burjassot 46100, Valencia (Spain)
2010-09-15
A discrete model characterizing heat and fluid flow in connection with thermal fluxes in a building is described and tested against experiment in this contribution. The model, based on a cellular automaton approach, relies on a set of a few quite simple rules and parameters in order to simulate the dynamic evolution of temperatures and energy flows in any water or brine based thermal energy distribution network in a building or system. Using an easy-to-record input, such as the instantaneous electrical power demand of the heating or cooling system, our model predicts time varying temperatures in characteristic spots and the related enthalpy flows whose simulation usually requires heavy computational tools and detailed knowledge of the network elements. As a particular example, we have applied our model to simulate an existing fan coil based hydronic heating system driven by a geothermal heat pump. When compared to the experimental temperature and thermal energy records, the outcome of the model coincides. (author)
A cellular automaton model for a bridge traffic bottleneck
Institute of Scientific and Technical Information of China (English)
Shifa Xiao; Lingjiang Kong; Muren Liu
2005-01-01
A cellular automaton (CA) model is proposed in this paper to analyze a bridge traffic bottleneck. The simulation results with this model show that there are several phase transitions in the traffic average density, velocity and flow for each lane under a periodic boundary condition. An unstable phase in the traffic average density and velocity for the upstream and downstream lanes of the bridge is shown in a range of initial traffic densities. The critical points of the phase transitions and the phenomenon of the unstable phase found in the simulation are also explained with the mean-field theory.
A Realistic Cellular Automaton Model for Synchronized Traffic Flow
Institute of Scientific and Technical Information of China (English)
ZHAO Bo-Han; HU Mao-Bin; JIANG Rui; WU Qing-Song
2009-01-01
A cellular automaton model is proposed to consider the anticipation effect in drivers' behavior. It is shown that the anticipation effect can be one of the origins of synchronized traffic flow. With anticipation effect, the congested traffic flow simulated by the model exhibits the features of synchronized flow. The spatiotemporal patterns induced by an on-ramp are also consistent with the three-phaee traffic theory. Since the origin of synchronized flow is still controversial, our work can shed some light on the mechanism of synchronized flow.
Ito equations out of domino cellular automaton with efficiency parameters
Czechowski, Zbigniew
2011-01-01
Ito equations are derived for simple stochastic cellular automaton with parameters and compared with results obtained from the histogram method. Good agreement for various parameters supports wide applicability of the Ito equation as a macroscopic model.
A THREE-DIMENSIONAL CELLULAR AUTOMATON SIMULATION FOR DENDRITIC GROWTH%枝晶生长的三维元胞自动机模拟
Institute of Scientific and Technical Information of China (English)
江鸿翔; 赵九洲
2011-01-01
Perhaps dendrite is the most observed solidification microstructure of many metallic materials. The dendritic morphologies show a dominating effect on the performance of casting products. A lot of work has been carried out to investigate the formation mechanism of dendritic microstructure. It is found that the development of dendritic microstructures is a complicated process controlled by the interplay of many factors such as thermal and solute transfer, capillary etc. Cellular automaton (CA) can simulate the solidification process with a high computational efficiency, thus, attracts great attentions. In recent years, progress has been made on the two dimensional CA models for the solidification microstructure formation. But up to date researches on three dimensional CA model are very limited. A combined cellular automaton-finite difference (CA-FD) model for the three dimensional simulation of dendritic growth was developed in this paper. Simulations were performed to investigate the dendritic growth in an undercooled Al-Cu alloy as well as in a directionally solidified Al-Cu alloy. The numerical results showed clearly the development of the free dendrite in the under-cooled melt and the microstructure evolution in the directionally solidified alloy and agreed well with the theoretical predictions and the experimental results.%通过将元胞自动机和有限差分方法相耦合,建立了立方体系金属和合金枝晶生长的三维模型.应用该模型,模拟了Al-Cu合金过冷熔体中自由枝晶的生长和定向凝固条件下Al-Cu合金凝固组织演变过程.模拟结果清楚展现了过冷熔体中自由枝晶的生长过程和定向凝固过程中枝晶的形成与淹没,与理论预测和实验结果相吻合,表明所发展的模型能够较准确地描述立方体系金属和合金的凝固组织演变过程.
Prediction of useful casting structure applying Cellular Automaton method
Directory of Open Access Journals (Sweden)
Z. Ignaszak
2009-07-01
Full Text Available The results of simulation investigations of primary casting’s structure made of hypoeutectic Al-Si alloy using the Calcosoft system with CAFE 3D (Cellular Automaton Finite Element module are presented. CAFE 3-D module let to predict the structure formation of complete castings indicating the spatial distribution of columnar and equiaxed grains. That simplified model concerns only hypoeutectic phase. Simulation investigations of structure concern the useful casting of camshaft which solidified in high-insulation mould with properly chills distribution. These conditions let to apply the expedient locally different simplified the grains blocs geometry which are called by the authors as pseudo-crystals. The mechanical properties in selected cross-sections of casing are estimated.
Quantum field as a quantum cellular automaton: The Dirac free evolution in one dimension
Energy Technology Data Exchange (ETDEWEB)
Bisio, Alessandro; D’Ariano, Giacomo Mauro; Tosini, Alessandro, E-mail: alessandro.tosini@unipv.it
2015-03-15
We present a quantum cellular automaton model in one space-dimension which has the Dirac equation as emergent. This model, a discrete-time and causal unitary evolution of a lattice of quantum systems, is derived from the assumptions of homogeneity, parity and time-reversal invariance. The comparison between the automaton and the Dirac evolutions is rigorously set as a discrimination problem between unitary channels. We derive an exact lower bound for the probability of error in the discrimination as an explicit function of the mass, the number and the momentum of the particles, and the duration of the evolution. Computing this bound with experimentally achievable values, we see that in that regime the QCA model cannot be discriminated from the usual Dirac evolution. Finally, we show that the evolution of one-particle states with narrow-band in momentum can be efficiently simulated by a dispersive differential equation for any regime. This analysis allows for a comparison with the dynamics of wave-packets as it is described by the usual Dirac equation. This paper is a first step in exploring the idea that quantum field theory could be grounded on a more fundamental quantum cellular automaton model and that physical dynamics could emerge from quantum information processing. In this framework, the discretization is a central ingredient and not only a tool for performing non-perturbative calculation as in lattice gauge theory. The automaton model, endowed with a precise notion of local observables and a full probabilistic interpretation, could lead to a coherent unification of a hypothetical discrete Planck scale with the usual Fermi scale of high-energy physics. - Highlights: • The free Dirac field in one space dimension as a quantum cellular automaton. • Large scale limit of the automaton and the emergence of the Dirac equation. • Dispersive differential equation for the evolution of smooth states on the automaton. • Optimal discrimination between the
Cellular automaton rules conserving the number of active sites
Boccara, N; Boccara, Nino; Fuks, Henryk
1997-01-01
This paper shows how to determine all the unidimensional two-state cellular automaton rules of a given number of inputs which conserve the number of active sites. These rules have to satisfy a necessary and sufficient condition. If the active sites are viewed as cells occupied by identical particles, these cellular automaton rules represent evolution operators of systems of identical interacting particles whose total number is conserved. Some of these rules, which allow motion in both directions, mimic ensembles of one-dimensional pseudo-random walkers. The corresponding stochastic processes are, however, not Gaussian.
Coarse-grained cellular automaton for traffic systems
Krawczyk, Malgorzata J
2012-01-01
A coarse-grained cellular automaton is proposed to simulate traffic systems. There, cells represent road sections. A cell can be in two states: jammed or passable. Numerical calculations are performed for a piece of square lattice with open boundary conditions, for the same piece with some cells removed and for a map of a small city. The results indicate the presence of a phase transition in the parameter space, between two macroscopic phases: passable and jammed. The results are supplemented by exact calculations of the stationary probabilities of states for the related Kripke structure constructed for the traffic system. There, the symmetry-based reduction of the state space allows to partially reduce the computational limitations of the numerical method.
A cellular automaton model for evacuation flow using game theory
Guan, Junbiao; Wang, Kaihua; Chen, Fangyue
2016-11-01
Game theory serves as a good tool to explore crowd dynamic conflicts during evacuation processes. The purpose of this study is to simulate the complicated interaction behavior among the conflicting pedestrians in an evacuation flow. Two types of pedestrians, namely, defectors and cooperators, are considered, and two important factors including fear index and cost coefficient are taken into account. By combining the snowdrift game theory with a cellular automaton (CA) model, it is shown that the increase of fear index and cost coefficient will lengthen the evacuation time, which is more apparent for large values of cost coefficient. Meanwhile, it is found that the defectors to cooperators ratio could always tend to consistent states despite different values of parameters, largely owing to self-organization effects.
A modified weighted probabilistic cellular automaton traffic flow model
Institute of Scientific and Technical Information of China (English)
Zhuang Qian; Jia Bin; Li Xin-Gang
2009-01-01
This paper modifies the weighted probabilistic cellular automaton model (Li X L,Kuang H,Song T,et al 2008Chin.Phys.B 17 2366) which considered a diversity of traffic behaviors under real traffic situations induced by various driving characters and habits.In the new model,the effects of the velocity at the last time step and drivers' desire for acceleration are taken into account.The fundamental diagram,spatial-temporal diagram,and the time series of one-minute data axe analyzed.The results show that this model reproduces synchronized flow.Finally,it simulates the on-ramp system with the proposed model.Some characteristics including the phase diagram are studied.
A cellular automaton for population diffusion in the homogeneous rectangular area
Directory of Open Access Journals (Sweden)
WenJun Zhang
2015-03-01
Full Text Available In this paper, a cellular automaton for population diffusion was introduced. A group of discrete partial differential equations was used to simulate population diffusion in the homogeneous rectangular area. The population dynamics was described by Malthus model, Logistic model, and oscillation model. The cellular automaton can be used to analyze the effects of initial distribution of organisms on diffusion process and distribution pattern, to estimate the diffusion speed and possible diffusion directions, and to determine the major regions occupied by organisms.
4D Cellular Automaton Track Finder in the CBM Experiment
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Akishina Valentina
2016-01-01
The FLES reconstruction and selection package consists of several modules: track finding, track fitting, short-lived particles finding, event building and event selection. The Cellular Automaton (CA track finder algorithm was adapted towards time-based reconstruction. In this article, we describe in detail the modification done to the algorithm, as well as the performance of the developed time-based CA approach.
Two-dimensional cellular automaton model of traffic flow with open boundaries
Tadaki, S I
1996-01-01
A two-dimensional cellular automaton model of traffic flow with open boundaries are investigated by computer simulations. The outflow of cars from the system and the average velocity are investigated. The time sequences of the outflow and average velocity have flicker noises in a jamming phase. The low density behavior are discussed with simple jam-free approximation.
EVOLUTION COMPLEXITY OF THEELEMENTARY CELLULAR AUTOMATON OF RULE 22
Institute of Scientific and Technical Information of China (English)
WangYi; JiangZhisong
2002-01-01
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.
Dirac Quantum Cellular Automaton from Split-step Quantum Walk
Mallick, Arindam
2015-01-01
Simulations of one quantum system by an other has an implications in realization of quantum machine that can imitate any quantum systems and solve problems that are not accessible to classical computers. One of the approach to engineer quantum simulations is to discretize the space-time degree of freedom in quantum dynamics and define the quantum cellular automata (QCA), a local unitary update rule on a lattice. Different models of QCA are constructed using different set of conditions which are not uniquely defined. The form of the operators in these model are not always in implementable configuration on an other system. Here, starting from a split-step discrete-time quantum walk (DTQW) which are uniquely defined for experimental implementation, we recover the Dirac quantum cellular automaton (DQCA). This will bridge the connection between Dirac equation(DE)-DQCA-DTQW and eliminate the explicit use of invariance, symmetries and limiting range of parameter to establish the connections. For a combination of par...
Cellular automaton-based position sensitive detector equalization
Energy Technology Data Exchange (ETDEWEB)
Ferrando, Nestor [Grupo de Diseno de Sistemas Digitales, Instituto de Aplicaciones de las Tecnologias de la Informacion y de las Comunicaciones Avanzadas, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)], E-mail: nesferjo@upvnet.upv.es; Herrero, V.; Cerda, J.; Lerche, C.W.; Colom, R.J.; Gadea, R.; Martinez, J.D.; Monzo, J.M.; Mateo, F.; Sebastia, A.; Benlloch, J.M. [Grupo de Diseno de Sistemas Digitales, Instituto de Aplicaciones de las Tecnologias de la Informacion y de las Comunicaciones Avanzadas, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)
2009-06-01
Indirect position detectors based on scintillator crystals lack of spacial uniformity in their response. This happens due to crystal inhomogeneities and gain differences among the photomultiplier anodes. In order to solve this, PESIC, an integrated front-end for multianode photomultiplier based nuclear imaging devices was created. One of its main features is the digitally programmable gain adjustment for every photomultiplier output. On another front, cellular automata have been proved to be a useful method for dynamic system modeling. In this paper, a cellular automaton which emulates the behavior of the scintillator crystal, the photomultiplier and the front-end is introduced. Thanks to this model, an automatic energy-based calibration of the detector can be done by configuring the cellular automaton with experimental data and making it evolve up to an stable state. This can be useful as a precalibration method of the detector.
Investigating CTL mediated killing with a 3D cellular automaton.
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Frederik Graw
2009-08-01
Full Text Available Cytotoxic T lymphocytes (CTLs are important immune effectors against intra-cellular pathogens. These cells search for infected cells and kill them. Recently developed experimental methods in combination with mathematical models allow for the quantification of the efficacy of CTL killing in vivo and, hence, for the estimation of parameters that characterize the effect of CTL killing on the target cell populations. It is not known how these population-level parameters relate to single-cell properties. To address this question, we developed a three-dimensional cellular automaton model of the region of the spleen where CTL killing takes place. The cellular automaton model describes the movement of different cell populations and their interactions. Cell movement patterns in our cellular automaton model agree with observations from two-photon microscopy. We find that, despite the strong spatial nature of the kinetics in our cellular automaton model, the killing of target cells by CTLs can be described by a term which is linear in the target cell frequency and saturates with respect to the CTL levels. Further, we find that the parameters describing CTL killing on the population level are most strongly impacted by the time a CTL needs to kill a target cell. This suggests that the killing of target cells, rather than their localization, is the limiting step in CTL killing dynamics given reasonable frequencies of CTL. Our analysis identifies additional experimental directions which are of particular importance to interpret estimates of killing rates and could advance our quantitative understanding of CTL killing.
Modeling Recrystallization of Austenite for C-Mn Steels during Hot Deformation by Cellular Automaton
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
By using a cellular automaton method, microstructure evolution of recrystallization in austenite during hot deformation was simulated for C-Mn steels. A model takes into account the influence of deformation temperature, strain, and strain rate on the dynamic recrystallization fraction, and the effect of the keeping time on the static recrystallization fraction based on a hot deformation test on a Gleeble-1500 simulator. In addition, the size changing of γ grains during continuous hot deformation was simulated by applying the model.
Three-level description of the domino cellular automaton
Czechowski, Zbigniew
2010-01-01
Inspired by the approach of kinetic theory of gases, a three-level description (microscopic, mesoscopic and macroscopic) of cellular automaton is presented. To provide an analytical treatment a simple domino cellular automaton with avalanches was constructed. Formulas concerning exact relations for density, clusters, avalanches and other parameters in an equilibrium state were derived. It appears that some relations are approximately valid for deviations from the equilibrium, so the adequate Ito equation could be constructed. The equation provides the time evolution description of some variable on the macroscopic level. The results also suggest a motive for applying of the procedure of construction of the Ito equation (from time series data) to natural time series.
Directory of Open Access Journals (Sweden)
Wang Kuangfei
2010-02-01
Full Text Available The microstructural evolution of Ti-45 at.%Al alloy during directional solidification was simulated by applying a solute diffusion controlled solidification model. The obtained results have shown that under high thermal gradients the stable primary spacing can be adjusted via branching or competitive growth. For dendritic structures formed under a high thermal gradient, the secondary dendrite arms are developed not very well in many cases due to the branching mechanism under a constrained dendritic growth condition. Furthermore, it has been observed that, with increasing pulling velocity, there exists a cell/dendrite transition region consisting of cells and dendrites, which varies with the thermal gradient in a contradicting way, i.e. increase of the thermal gradient leading to the decrease of the range of the transition region. The simulations agree reasonably well with experiment results.
Lu, Lili; Ren, Gang; Wang, Wei; Chan, Ching-Yao; Wang, Jian
2016-10-01
At unsignalized crosswalks, interactions between pedestrians and vehicles often lead to traffic safety hazards due to absence of traffic control and unclear right-of-ways. To address this safety problem, there is a need to understand the interaction behaviors of pedestrians and vehicles that are complicated by a variety of traffic and roadway attributes. The prime objective of this study is to establish a reliable simulation model to represent the vehicle yielding and pedestrian crossing behaviors at unsignalized crosswalks in a realistic way. The model is calibrated with detailed behavioral data collected and extracted from field observations. The capability of the calibrated model in predicting the pedestrian-interaction events as well as estimating the driver yielding rate and pedestrian delay are also tested and demonstrated. Meanwhile, the traffic dynamics in the vicinity of the crosswalk can be meaningfully represented with simulation results based on the model. Moreover, with the definitions of the vehicle-pedestrian conflicts, the proposed model is capable to evaluate the pedestrian safety. Thereby, the simulation model has the potential to serve as a useful tool for assessing safety performance and traffic operations at existing facilities. Furthermore, the model can enable the evaluation of policy effectiveness and the selection of engineering treatments at unsignalized crosswalks to improve safety and efficiency of pedestrian crossing.
Cellular automaton model considering headway-distance effect
Institute of Scientific and Technical Information of China (English)
Hu Shou-Xin; Gao Kun; Wang Bing-Hong; Lu Yu-Feng
2008-01-01
This paper presents a cellular automaton model for single-lane traffic flow.On the basis of the Nagel-Schreckenberg (NS) model,it further considers the effect of headway-distance between two successive cars on the randomization of the latter one.In numerical simulations,this model shows the following characteristics.(1) With a simple structure,this model succeeds in reproducing the hysteresis effect,which is absent in the NS model.(2) Compared with the slow-tostart models,this model exhibits a local fundamental diagram which is more consistent to empirical observations.(3)This model has much higher efficiency in dissolving congestions compared with the so-called NS model with velocitydependent randomization (VDR model).(4) This model is more robust when facing traffic obstructions.It can resist much longer shock times and has much shorter relaxation times on the other hand.To summarize,compared with the existing models,this model is quite simple in structure,but has good characteristics.
A Quantum Relativistic Prisoner's Dilemma Cellular Automaton
Alonso-Sanz, Ramón; Carvalho, Márcio; Situ, Haozhen
2016-10-01
The effect of variable entangling on the dynamics of a spatial quantum relativistic formulation of the iterated prisoner's dilemma game is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. The game is assessed in fair and unfair contests.
A Modified Cellular Automaton in Lagrange Form with Velocity Dependent Acceleration Rate
Directory of Open Access Journals (Sweden)
K. Rawat
2011-07-01
Full Text Available Road traffic micro simulations based on the individual motion of all the involvedvehicles are now recognized as an important tool to describe, understand and manage roadtraffic. With increasing computational power, simulating traffic in microscopic level bymeans of Cellular Automaton becomes a real possibility. Based on Nasch model of singlelane traffic flow, a modified Cellular Automaton traffic flow model is proposed to simulatehomogeneous and mixed type traffic flow. The model is developed with modified cell size,incorporating different acceleration characteristics depending upon the speed of eachindividual vehicle. Comparisons are made between Nasch model and modified model. It isobserved that slope of congested branch is changed for modified model as the vehicle thatare coming out of jam having dissimilar acceleration capabilities, therefore there is not asudden drop in throughput near critical density c .
Cellular automaton for realistic modelling of landslides
Segrè, E; Enrico Segre; Chiara Deangeli
1994-01-01
We develop a numerical model for the simulation of debris flow in landslides over a complex three dimensional topography. The model is based on a lattice, in which debris can be transferred among nearest neighbours according to established empirical relationships for granular flows. The model is validated comparing its results with reported field data. Our model is in fact a realistic elaboration of simpler ``sandpile automata'', which have in recent years been studied as supposedly paradigmatic of ``self organized criticality''. Statistics and scaling properties of the simulation are examined, showing that the model has an intermittent behaviour.
Modeling and Experimental Study of Soft Error Propagation Based on Cellular Automaton
2016-01-01
Aiming to estimate SEE soft error performance of complex electronic systems, a soft error propagation model based on cellular automaton is proposed and an estimation methodology based on circuit partitioning and error propagation is presented. Simulations indicate that different fault grade jamming and different coupling factors between cells are the main parameters influencing the vulnerability of the system. Accelerated radiation experiments have been developed to determine the main paramet...
An Extended Cellular Automaton Model for Train Traffic Flow on the Dedicated Passenger Lines
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Wenbo Zhao
2014-01-01
Full Text Available As one of the key components for the railway transportation system, the Train Operation Diagram can be greatly influenced by many extrinsic and intrinsic factors. Therefore, the railway train flow has shown the strong nonlinear characteristics, which makes it quite difficult to take further relative studies. Fortunately, the cellular automaton model has its own advantages in solving nonlinear problems and traffic flow simulation. Considering the mixed features of multispeed running trains on the passenger dedicated lines, this paper presents a new train model under the moving block system with different types of trains running with the cellular automaton idea. By analyzing such key factors as the maintenance skylight, the proportion of the multispeed running trains, and the distance between adjacent stations and departure intervals, the corresponding running rules for the cellular automaton model are reestablished herewith. By means of this CA model, the program of train running system is designed to analyze the potential impact on railway carrying capacity by various factors; the model can also be implemented to simulate the actual train running process and to draw the train operation diagram by computers. Basically the theory can be applied to organize the train operation on the dedicated passenger lines.
Infinity computations in cellular automaton forest-fire model
Iudin, D. I.; Sergeyev, Ya. D.; Hayakawa, M.
2015-03-01
Recently a number of traditional models related to the percolation theory has been considered by means of a new computational methodology that does not use Cantor's ideas and describes infinite and infinitesimal numbers in accordance with the principle 'The whole is greater than the part' (Euclid's Common Notion 5). Here we apply the new arithmetic to a cellular automaton forest-fire model which is connected with the percolation methodology and in some sense combines the dynamic and the static percolation problems and under certain conditions exhibits critical fluctuations. It is well known that there exist two versions of the model: real forest-fire model where fire catches adjacent trees in the forest in the step by step manner and simplified version with instantaneous combustion. Using new approach we observe that in both situations we deal with the same model but with different time resolution. We show that depending on the "microscope" we use the same cellular automaton forest-fire model reveals either instantaneous forest combustion or step by step firing. By means of the new approach it was also observed that as far as we choose an infinitesimal tree growing rate and infinitesimal ratio between the ignition probability and the growth probability we determine the measure or extent of the system size infinity that provides the criticality of the system dynamics. Correspondent inequalities for grosspowers are derived.
A weakly universal cellular automaton in the hyperbolic 3D space with three states
Maurice, Margenstern
2010-01-01
In this paper, we significantly improve a previous result by the same author showing the existence of a weakly universal cellular automaton with five states living in the hyperbolic 3D-space. Here, we get such a cellular automaton with three states only.
Modeling the dendritic evolution and micro-segregation of cast alloy with cellular automaton
Institute of Scientific and Technical Information of China (English)
Qiang Li; Dianzhong Li; Bainian Qian
2004-01-01
In order to precisely describe the dendritic morphology and micro-segregation during solidification process, a novel continuous model concerning the different physical properties in the solid phase, liquid phase and interface is developed. Coupling the heat and solute diffusion with the transition rules, the dendrite evolution is simulated by cellular automaton method. Then, the solidification microstructure evolution of a small ingot is simulated by using this method. The simulated results indicate that this model can simulate the dendrite growth, show the second dendrite arm and tertiary dendrite arm, and reveal the micro-segregation in the inter-dendritic zones. Furthermore, the columnar-to-equiaxed transition (CET) is predicted.
Dunes morphologies and superimposed bedforms in a cellular automaton dune model
Zhang, D.; Narteau, C.; Rozier, O.; Claudin, P.
2009-04-01
We use a new 3D cellular automaton model for bedform dynamics in which individual physical processes such as erosion, deposition and transport are implemented by nearest neighbor interactions and a time-dependent stochastic process. Simultaneously, a lattice gas cellular automaton model is used to compute the flow and quantify the bed shear stress on the topography. Local erosion rates are taken proportional to the shear stress in such a way that there is a complete feedback mechanism between flow and bedform dynamics. In the numerical simulations of dune fields, we observe the formation and the evolution of barchan, transverse, longitudinal and star dunes. For all these types of dunes, we observe the emergence of superimposed bedforms when dunes are large enough. Then, we use the same model under different initial conditions, and we perform the linear stability analysis of a flat sand bed disturbed by a small sinusoidal perturbation. Comparing the most unstable wavelength in the model with the characteristic size of secondary bedforms in nature, we determine the length and time scales of our cellular automaton model. Thus, we establish a link between discrete and continuous approaches and open new perspectives for modeling and quantification of complex patterns in dune fields.
Motor Schema-Based Cellular Automaton Model for Pedestrian Dynamics
Weng, Wenguo; Hasemi, Yuji; Fan, Weicheng
A new cellular automaton model for pedestrian dynamics based on motor schema is presented. Each pedestrian is treated as an intelligent mobile robot, and motor schemas including move-to-goal, avoid-away and avoid-around drive pedestrians to interact with their environment. We investigate the phenomenon of many pedestrians with different move velocities escaping from a room. The results show that the pedestrian with high velocity have predominance in competitive evacuation, if we only consider repulsion from or avoiding around other pedestrians, and interaction with each other leads to disordered evacuation, i.e., decreased evacuation efficiency. Extensions of the model using learning algorithms for controlling pedestrians, i.e., reinforcement learning, neural network and genetic algorithms, etc. are noted.
A cellular automaton model for neurogenesis in Drosophila
Luthi, Pascal O.; Chopard, Bastien; Preiss, Anette; Ramsden, Jeremy J.
1998-07-01
A cellular automaton (CA) is constructed for the formation of the central nervous system of the Drosophila embryo. This is an experimentally well-studied system in which complex interactions between neighbouring cells appear to drive their differentiation into different types. It appears that all the cells initially have the potential to become neuroblasts, and all strive to this end, but those which differentiate first block their as yet undifferentiated neighbours from doing so. The CA makes use of observational evidence for a lateral inhibition mechanism involving signalling products S of the ‘proneural’ or neuralizing genes. The key concept of the model is that cells are continuously producing S, but the production rate is lowered by inhibitory signals received from neighbouring cells which have advanced further along the developmental pathway. Comparison with experimental data shows that it well accounts for the observed proportion of neuroectodermal cells delaminating as neuroblasts.
Two dimensional cellular automaton for evacuation modeling: hybrid shuffle update
Arita, Chikashi; Appert-Rolland, Cécile
2015-01-01
We consider a cellular automaton model with a static floor field for pedestrians evacuating a room. After identifying some properties of real pedestrian flows, we discuss various update schemes, and we introduce a new one, the hybrid shuffle update. The properties specific to pedestrians are incorporated in variables associated to particles called phases, that represent their step cycles. The dynamics of the phases gives naturally raise to some friction, and allows to reproduce several features observed in experiments. We study in particular the crossover between a low- and a high-density regime that occurs when the density of pedestrian increases, the dependency of the outflow in the strength of the floor field, and the shape of the queue in front of the exit.
Bialecki, Mariusz
2010-01-01
Inspired by extremely simplified view of the earthquakes we propose the stochastic domino cellular automaton model exhibiting avalanches. From elementary combinatorial arguments we derive a set of nonlinear equations describing the automaton. Exact relations between the average parameters of the model are presented. Depending on imposed triggering, the model reproduces both exponential and inverse power statistics of clusters.
A cellular automaton for the signed particle formulation of quantum mechanics
Sellier, J. M.; Kapanova, K. G.; Dimov, I.
2017-02-01
Recently, a new formulation of quantum mechanics, based on the concept of signed particles, has been suggested. In this paper, we introduce a cellular automaton which mimics the dynamics of quantum objects in the phase-space in a time-dependent fashion. This is twofold: it provides a simplified and accessible language to non-physicists who wants to simulate quantum mechanical systems, at the same time it enables a different way to explore the laws of Physics. Moreover, it opens the way towards hybrid simulations of quantum systems by combining full quantum models with cellular automata when the former fail. In order to show the validity of the suggested cellular automaton and its combination with the signed particle formalism, several numerical experiments are performed, showing very promising results. Being this article a preliminary study on quantum simulations in phase-space by means of cellular automata, some conclusions are drawn about the encouraging results obtained so far and the possible future developments.
CATALAN NUMBERS, DYCK LANGUAGE AND TIME SERIES OF ELEMENTARY CELLULAR AUTOMATON OF RULE 56
Institute of Scientific and Technical Information of China (English)
QIN Dakang; XIE Huimin
2005-01-01
A new approach to study the evolution complexity of cellular automata is proposed and explained thoroughly by an example of elementary cellular automaton of rule 56. Using the tools of distinct excluded blocks, computational search and symbolic dynamics, the mathematical structure underlying the time series generated from the elementary cellular automaton of rule 56 is analyzed and its complexity is determined, in which the Dyck language and Catalan numbers emerge naturally.
Predictability of the large relaxations in a cellular automaton model
Energy Technology Data Exchange (ETDEWEB)
Tejedor, Alejandro; Ambroj, Samuel; Gomez, Javier B; Pacheco, Amalio F [Faculty of Sciences, University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain)
2008-09-19
A simple one-dimensional cellular automaton model with threshold dynamics is introduced. It is loaded at a uniform rate and unloaded by abrupt relaxations. The cumulative distribution of the size of the relaxations is analytically computed and behaves as a power law with an exponent equal to -1. This coincides with the phenomenological Gutenberg-Richter behavior observed in seismology for the cumulative statistics of earthquakes at the regional or global scale. The key point of the model is the zero-load state of the system after the occurrence of any relaxation, no matter what its size. This leads to an equipartition of probability between all possible load configurations in the system during the successive loading cycles. Each cycle ends with the occurrence of the greatest-or characteristic-relaxation in the system. The duration of the cycles in the model is statistically distributed with a coefficient of variation ranging from 0.5 to 1. The predictability of the characteristic relaxations is evaluated by means of error diagrams. This model illustrates the value taking into account the refractory periods to obtain a considerable gain in the quality of the predictions.
4D Cellular Automaton Track Finder in the CBM Experiment
Akishina, Valentina; Kisel, Ivan
2016-11-01
The CBM experiment (FAIR/GSI, Darmstadt, Germany) will focus on the measurement of rare probes at interaction rates up to 10MHz with data flow of up to 1 TB/s. It requires a novel read-out and data-acquisition concept with self-triggered electronics and free-streaming data. In this case resolving different collisions is a non-trivial task and event building must be performed in software online. That requires full online event reconstruction and selection not only in space, but also in time, so-called 4D event building and selection. This is a task of the First-Level Event Selection (FLES). The FLES reconstruction and selection package consists of several modules: track finding, track fitting, short-lived particles finding, event building and event selection. The Cellular Automaton (CA) track finder algorithm was adapted towards time-based reconstruction. In this article, we describe in detail the modification done to the algorithm, as well as the performance of the developed time-based CA approach.
Albuquerque,Jones O.; Bocanegra,Silvana; Ferrer-Savall, Jordi; López Codina, Daniel; Souza, Marco Antônio de; Souza Santos, Reinaldo; Barbosa, Constança
2013-01-01
This work presents a Cellular Automata model to characterize the social and environmental factors which contribute for the analysis of the expansion process of Schistosoma mansoni infection in Pernambuco - Brazil. The model has been experimented with a set of two years real data from a study area at North Coast of Pernambuco – Brazil. The main constraint equations, the modelling process and the results obtained until now with the simulating scenarios generated are presented here. The results ...
An implementation of cellular automaton model for single-line train working diagram
Institute of Scientific and Technical Information of China (English)
Hua Wei; Liu Jun
2006-01-01
According to the railway transportation system's characteristics,a new cellular automaton model for the singleline railway system is presented in this paper.Based on this model,several simulations were done to imitate the train operation under three working diagrams.From a different angle the results show how the organization of train operation impacts on the railway carrying capacity.By using the non-parallel train working diagram the influence of fast-train on slow-train is found to be the strongest.Many slow-trains have to wait in-between neighbouring stations to let the fast-train(s) pass through first.So the slow-train will advance like a wave propagating from the departure station to the arrival station.This also resembles the situation of a highway jammed traffic flow.Furthermore,the nonuniformity of travel times between the sections also greatly limits the railway carrying capacity.After converting the nonuniform sections into the sections with uniform travel times while the total travel time is kept unchanged,all three carrying capacities are improved greatly as shown by simulation.It also shows that the cellular automaton model is an effective and feasible way to investigate the railway transDortation system.
Energy Technology Data Exchange (ETDEWEB)
Tian, Jun-fang, E-mail: tianhustbjtu@hotmail.com [MOE Key Laboratory for Urban Transportation Complex Systems Theory and Technology, Beijing Jiaotong University, Beijing 100044 (China); Yuan, Zhen-zhou; Jia, Bin; Fan, Hong-qiang; Wang, Tao [MOE Key Laboratory for Urban Transportation Complex Systems Theory and Technology, Beijing Jiaotong University, Beijing 100044 (China)
2012-09-10
Velocity effect and critical velocity are incorporated into the average space gap cellular automaton model [J.F. Tian, et al., Phys. A 391 (2012) 3129], which was able to reproduce many spatiotemporal dynamics reported by the three-phase theory except the synchronized outflow of wide moving jams. The physics of traffic breakdown has been explained. Various congested patterns induced by the on-ramp are reproduced. It is shown that the occurrence of synchronized outflow, free outflow of wide moving jams is closely related with drivers time delay in acceleration at the downstream jam front and the critical velocity, respectively. -- Highlights: ► Velocity effect is added into average space gap cellular automaton model. ► The physics of traffic breakdown has been explained. ► The probabilistic nature of traffic breakdown is simulated. ► Various congested patterns induced by the on-ramp are reproduced. ► The occurrence of synchronized outflow of jams depends on drivers time delay.
Institute of Scientific and Technical Information of China (English)
何红弟; 董力耘; 戴世强
2006-01-01
Traffic flows controlled by traffic light strategies were investigated via a cellular automaton model with anticipation, which is suitable for describing urban traffic. Three kinds of strategies, i.e., synchronized, green-wave and random switching lights, were designed, simulated and compared with each other. It is shown that the green-wave strategy is only valid at lower density and there is not an effective way with the three strategies to improve the efficiency of traffic flow at high density.
Merdan, Z.; Güzelsoy, E.
2012-05-01
The four-dimensional Ising model is simulated on the Creutz cellular automaton using finite-size lattices with linear dimension 4≤ L≤8. The exponents in the finite-size scaling relations for the order parameter and the magnetic susceptibility at the finite-lattice critical temperature are computed to be β=0.49(7), β=0.49(5), β=0.50(1) and γ=1.04(4), γ=1.03(4), γ=1.02(4) for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the obtained results are consistent with the renormalization group predictions of β=0.5 and γ=1. The values for the critical temperature of the infinite lattice T c (∞)=6.6788(65), T c (∞)=6.6798(69), T c (∞)=6.6802(70) are obtained from the straight-line fit of the magnetic susceptibility maxima using 4≤ L≤8 for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the obtained results are in very good agreement with the series expansion results of T c (∞)=6.6817(15), T c (∞)=6.6802(2), the dynamic Monte Carlo result of T c (∞)=6.6803(1), the cluster Monte Carlo result of T c (∞)=6.680(1) and the Monte Carlo using Metropolis and Wolff-cluster algorithm result of T c (∞)=6.6802632±5×10-5.
Micro-macroscopic coupling in the cellular automaton model of solidification
Directory of Open Access Journals (Sweden)
Vinicius Bertolazzi Biscuola
2010-12-01
Full Text Available A cellular automaton (CA model to predict the formation of grain macrostructure during solidification has been implemented and the coupling between the microscopic and the macroscopic submodels has been investigated. The microscopic submodel simulates the nucleation and growth of grains, whereas the macroscopic solves the heat conduction equation. The directional solidification of an Al-7 wt. (% Si alloy was simulated, enabling the calculation of the temperature and solid fraction profiles. The calculated temperature was used to obtain the solid fraction profile by an application of Scheil equation. This solid fraction disagrees with that calculated in the micro-macro coupling of the model, although this coupling is completely based on Scheil equation. Careful examination of the discrepancies shows that it is a result of the undercoolings for nucleation and growth of grains and also of the interpolations of enthalpy change and temperature from the finite volume mesh to the CA cell mesh.
Jiao, Yang
2011-01-01
Understanding tumor invasion and metastasis is of crucial importance for both fundamental cancer research and clinical practice. In vitro experiments have established that the invasive growth of malignant tumors is characterized by the dendritic invasive branches composed of chains of tumor cells emanating from the primary tumor mass. The preponderance of previous tumor simulations focused on non-invasive (or proliferative) growth. The formation of the invasive cell chains and their interactions with the primary tumor mass and host microenvironment are not well understood. Here, we present a novel cellular automaton (CA) model that enables one to efficiently simulate invasive tumor growth in a heterogeneous host microenvironment. By taking into account a variety of microscopic-scale tumor-host interactions, including the short-range mechanical interactions between tumor cells and tumor stroma, degradation of extracellular matrix by the invasive cells and oxygen/nutrient gradient driven cell motions, our CA mo...
Cellular automaton model of precipitation/dissolution coupled with solute transport
Karapiperis, T
1995-01-01
ABSTRACT Precipitation/dissolution reactions coupled with solute transport are modelled as a cellular automaton in which solute molecules perform a random walk on a regular lattice and react according to a local probabilistic rule. Stationary solid particles dissolve with a certain probability and, provided solid is already present or the solution is saturated, solute particles have a probability to precipitate. In our simulation of the dissolution of a solid block inside uniformly flowing water we obtain solid precipitation downstream from the original solid edge, in contrast to the standard reaction-transport equations. The observed effect is the result of fluctuations in solute density and diminishes when we average over a larger ensemble. The additional precipitation of solid is accompanied by a substantial reduction in the relatively small solute concentration. The model is appropriate for the study of the rôle of intrinsic fluctuations in the presence of reaction thresholds and can be employed to inves...
An improved cellular automaton model considering the effect of traffic lights and driving behaviour
Institute of Scientific and Technical Information of China (English)
He Hong-Di; Lu Wei-Zhen; Dong Li-Yun
2011-01-01
This paper proposes an improved cellular automaton model to describe the urban traffic flow with the consideration of traffic light and driving behaviour effects. Based on the model, the characteristics of the urban traffic flow on a singlelane road are investigated under three different control strategies, i.e., the synchronized, the green wave and the random strategies. The fundamental diagrams and time-space patterns of the traffic flows are provided for these strategies respectively. It finds that the dynamical transition to the congested flow appears when the vehicle density is higher than a critical level. The saturated flow is less dependent on the cycle time and the strategies of the traffic light control,while the critical vehicle density varies with the cycle time and the strategies. Simulated results indicate that the green wave strategy is proven to be the most effective one among the above three control strategies.
An improved cellular automaton model considering the effect of traffic lights and driving behaviour
He, Hong-Di; Lu, Wei-Zhen; Dong, Li-Yun
2011-04-01
This paper proposes an improved cellular automaton model to describe the urban traffic flow with the consideration of traffic light and driving behaviour effects. Based on the model, the characteristics of the urban traffic flow on a single-lane road are investigated under three different control strategies, i.e., the synchronized, the green wave and the random strategies. The fundamental diagrams and time-space patterns of the traffic flows are provided for these strategies respectively. It finds that the dynamical transition to the congested flow appears when the vehicle density is higher than a critical level. The saturated flow is less dependent on the cycle time and the strategies of the traffic light control, while the critical vehicle density varies with the cycle time and the strategies. Simulated results indicate that the green wave strategy is proven to be the most effective one among the above three control strategies.
Steady state speed distribution analysis for a combined cellular automaton traffic model
Institute of Scientific and Technical Information of China (English)
Wang Jun-Feng; Chen Gui-Sheng; Liu Jin
2008-01-01
Cellular Automaton (CA) baaed traffic flow models have been extensively studied due to their effectiveness and simplicity in recent years. This paper develops a discrete time Markov chain (DTMC) analytical framework for a Nagel-Schreckenberg and Fukui-Ishibashi combined CA model (W2H traffic flow model) from microscopic point of view to capture the macroscopic steady state speed distributions. The inter-vehicle spacing Markov chain and the steady state speed Markov chain are proved to be irreducible and ergodie. The theoretical speed probability distributions depending on the traffic density and stochastic delay probability are in good accordance with numerical simulations. The derived fundamental diagram of the average speed from theoretical speed distributions is equivalent to the results in the previous work.
A traffic flow cellular automaton model to considering drivers' learning and forgetting behaviour
Institute of Scientific and Technical Information of China (English)
Ding Jian-Xun; Huang Hai-Jun; Tian Qiong
2011-01-01
It is known that the commonly used NaSch cellular automaton (CA) model and its modifications can help explain the internal causes of the macro phenomena of traffic flow. However, the randomization probability of vehicle velocity used in these models is assumed to be an exogenous constant or a conditional constant, which cannot reflect the learning and forgetting behaviour of drivers with historical experiences. This paper further modifies the NaSch model by enabling the randomization probability to be adjusted on the bases of drivers' memory. The Markov properties of this modified model are discussed. Analytical and simulation results show that the traffic fundamental diagrams can be indeed improved when considering drivers' intelligent behaviour. Some new features of traffic are revealed by differently combining the model parameters representing learning and forgetting behaviour.
Cellular Automaton Models of Highway Traffic Flow Considering Lane-Control and Speed-Control
Institute of Scientific and Technical Information of China (English)
钱勇生; 李文俊; 曾俊伟; 王敏; 杜加伟; 广晓平
2011-01-01
As two kinds of management modes of highway tramc control, lane-control, and speed-control produce different effect under different conditions. In this paper, traffic flow cellular automaton models for four-lane highway system with two opposing directions under the above two modes are established considering car and truck mixed running. Through computer numerical simulating, the fundamental diagrams with different parameters are obtained, and after the analysis of density-flux diagrams, the variation discipline of flux with traffic density under different control models is gained. The results indicate that, compared with lane-control, utilization ratio of road can be further improved with speed-control when the truck number increases. The research result is of great significance for reasonable providing theoretical guidance for highway traffic control.
Quantum field theoretic behavior of a deterministic cellular automaton
Hooft, G. 't; Isler, K.; Kalitzin, S.
1992-01-01
A certain class of cellular automata in 1 space + 1 time dimension is shown to be closely related to quantum field theories containing Dirac fermions. In the massless case this relation can be studied analytically, while the introduction of Dirac mass requires numerical simulations. We show that in
Institute of Scientific and Technical Information of China (English)
石玉峰; 许庆彦; 柳百成
2012-01-01
Based on the binary cellular automaton method, a modified cellular automaton model for temary alloys is developed to simulate dendrite growth controlled by solutal effects and microsegregation in the low Peclet number regime by coupling PanEngine, which is a multicomponent thermodynamic and equilibrium calculation engine. The model can be used to calculate the interfacial equilibrium composition by considering the influence of Gibbs-Thomson effect induced curvature undercooling, and multicomponents contributed constitutional undercooling. Meanwhile, the growth velocity of interface is determined by solving the solute conservation equation simultaneously with dimensionless solute supersaturation equation for each alloying element. Moreover, equilibrium liquidus temper- ature and equilibrium solid concentration at the interface are derived by PanEngine. Free dendrite growth of A1-7%Si-χMg temary alloys is simulated by the present model, which shows that the increase of solute Mg can suppress the growths of both primary and secondary dendrite arms. Meanwhile, constrained columnar dendrite growth of A1-7%Si-0.5%Mg with the increases of pulling veloc- ity and constant thermal gradient during directional solidification is calculated. The results reveal the competitive growth of columnar dendrites, and demonstrate that the primary dendrite arm spacing would decrease as the pulling velocity increases, which accords well with the Hunt model.%在二元合金元胞自动机模型的基础上，通过耦合多元合金热力学相平衡求解器PanEngine，建立了三元合金改进的元胞自动机模型，可模拟初生相枝晶的生长过程．模型考虑了曲率过冷和成分过冷对界面平衡溶质成分的影响，通过不同组元的无量纲溶质过饱和度方程和界面溶质守恒方程之间的耦合来求解界面生长速率，并通过PanEngine计算界面处的液相线温度．采用本模型模拟了A1—7％Si-χMg三元合金自由枝晶的
A quantum relativistic battle of the sexes cellular automaton
Alonso-Sanz, Ramón; Situ, Haozhen
2017-02-01
The effect of variable entangling on the dynamics of a spatial quantum relativistic formulation of the iterated battle of the sexes game is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. The game is assessed in fair and unfair contests. Despite the full range of quantum parameters initially accessible, they promptly converge into fairly stable configurations, that often show rich spatial structures in simulations with no negligible entanglement.
Danila, Bogdan; Mocanu, Gabriela
2015-01-01
We investigate the transition to Self Organized Criticality in a two-dimensional model of a flux tube with a background flow. The magnetic induction equation, represented by a partial differential equation with a stochastic source term, is discretized and implemented on a two dimensional cellular automaton. The energy released by the automaton during one relaxation event is the magnetic energy. As a result of the simulations we obtain the time evolution of the energy release, of the system control parameter, of the event lifetime distribution and of the event size distribution, respectively, and we establish that a Self Organized Critical state is indeed reached by the system. Moreover, energetic initial impulses in the magnetohydrodynamic flow can lead to one dimensional signatures in the magnetic two dimensional system, once the Self Organized Critical regime is established. The applications of the model for the study of Gamma Ray Bursts is briefly considered, and it is shown that some astrophysical paramet...
Dirac Cellular Automaton from Split-step Quantum Walk.
Mallick, Arindam; Chandrashekar, C M
2016-05-17
Simulations of one quantum system by an other has an implication in realization of quantum machine that can imitate any quantum system and solve problems that are not accessible to classical computers. One of the approach to engineer quantum simulations is to discretize the space-time degree of freedom in quantum dynamics and define the quantum cellular automata (QCA), a local unitary update rule on a lattice. Different models of QCA are constructed using set of conditions which are not unique and are not always in implementable configuration on any other system. Dirac Cellular Automata (DCA) is one such model constructed for Dirac Hamiltonian (DH) in free quantum field theory. Here, starting from a split-step discrete-time quantum walk (QW) which is uniquely defined for experimental implementation, we recover the DCA along with all the fine oscillations in position space and bridge the missing connection between DH-DCA-QW. We will present the contribution of the parameters resulting in the fine oscillations on the Zitterbewegung frequency and entanglement. The tuneability of the evolution parameters demonstrated in experimental implementation of QW will establish it as an efficient tool to design quantum simulator and approach quantum field theory from principles of quantum information theory.
Dirac Cellular Automaton from Split-step Quantum Walk
Mallick, Arindam; Chandrashekar, C. M.
2016-05-01
Simulations of one quantum system by an other has an implication in realization of quantum machine that can imitate any quantum system and solve problems that are not accessible to classical computers. One of the approach to engineer quantum simulations is to discretize the space-time degree of freedom in quantum dynamics and define the quantum cellular automata (QCA), a local unitary update rule on a lattice. Different models of QCA are constructed using set of conditions which are not unique and are not always in implementable configuration on any other system. Dirac Cellular Automata (DCA) is one such model constructed for Dirac Hamiltonian (DH) in free quantum field theory. Here, starting from a split-step discrete-time quantum walk (QW) which is uniquely defined for experimental implementation, we recover the DCA along with all the fine oscillations in position space and bridge the missing connection between DH-DCA-QW. We will present the contribution of the parameters resulting in the fine oscillations on the Zitterbewegung frequency and entanglement. The tuneability of the evolution parameters demonstrated in experimental implementation of QW will establish it as an efficient tool to design quantum simulator and approach quantum field theory from principles of quantum information theory.
Swallowing a cellular automaton pill: predicting drug release from a matrix tablet
Buchla, Ezra; Najera, Aisha; Radunskaya, Ami
2012-01-01
Matrix tablets are drug delivery devices designed to release a drug in a controlled manner over an extended period of time. We develop a cellular automaton (CA) model for the dissolution and release of a water-soluble drug and excipient from a matrix tablet of water-insoluble polymer. Cells of the CA are occupied by drug, excipient, water or polymer and the CA updating rules simulate the dissolution of drug and excipient and the subsequent diffusion of the dissolved substances. In addition we simulate the possible fracture of brittle drug and excipient powders during the tablet compression and the melting of the polymer during a possible thermal curing process. Different stirring mechanisms that facilitate the transport of dissolved drug in the fluid in which the tablet is immersed are modeled in the water cells adjacent to the boundary of the tablet. We find that our simulations can reproduce experimental drug release profiles. Our simulation tool can be used to streamline the formulation and production of s...
A Modified Cellular Automaton Method for the Modeling of the Dendritic Morphology of Binary Alloys
Institute of Scientific and Technical Information of China (English)
LIU Ying; XU Qingyan; LIU Baicheng
2006-01-01
A cellular automaton (CA)-based model for the precise two-dimensional simulation of the dendritic morphology of cast aluminum alloys was developed. Compared with previous CA models, the new model considers the solidification process in more detail, solving the solute and heat conservation equations in the modeling domain, including calculation of the solid fraction, the tip velocity, and the solute diffusion process, all of which have significant influence on the dendrite evolution. The rotating grids technique was used in the simulation to avoid anisotropy introduced by the square grid. Dendritic grain profiles for different crystallographic orientations show the existence of a great number of regular and parallel secondary and tertiary arms. The simulation results for the secondary arm spacing and grain size were compared with experimental data and with results reported in the literature. A good agreement was found between the simulated results and the experimental data. It can be concluded that the model can be used to predict the dendritic microstructure of aluminum alloy in a quantitative manner.
Intrinsic Simulations between Stochastic Cellular Automata
Directory of Open Access Journals (Sweden)
Pablo Arrighi
2012-08-01
Full Text Available The paper proposes a simple formalism for dealing with deterministic, non-deterministic and stochastic cellular automata in a unifying and composable manner. Armed with this formalism, we extend the notion of intrinsic simulation between deterministic cellular automata, to the non-deterministic and stochastic settings. We then provide explicit tools to prove or disprove the existence of such a simulation between two stochastic cellular automata, even though the intrinsic simulation relation is shown to be undecidable in dimension two and higher. The key result behind this is the caracterization of equality of stochastic global maps by the existence of a coupling between the random sources. We then prove that there is a universal non-deterministic cellular automaton, but no universal stochastic cellular automaton. Yet we provide stochastic cellular automata achieving optimal partial universality.
A cellular automaton model for ship traffic flow in waterways
Qi, Le; Zheng, Zhongyi; Gang, Longhui
2017-04-01
With the development of marine traffic, waterways become congested and more complicated traffic phenomena in ship traffic flow are observed. It is important and necessary to build a ship traffic flow model based on cellular automata (CAs) to study the phenomena and improve marine transportation efficiency and safety. Spatial discretization rules for waterways and update rules for ship movement are two important issues that are very different from vehicle traffic. To solve these issues, a CA model for ship traffic flow, called a spatial-logical mapping (SLM) model, is presented. In this model, the spatial discretization rules are improved by adding a mapping rule. And the dynamic ship domain model is considered in the update rules to describe ships' interaction more exactly. Take the ship traffic flow in the Singapore Strait for example, some simulations were carried out and compared. The simulations show that the SLM model could avoid ship pseudo lane-change efficiently, which is caused by traditional spatial discretization rules. The ship velocity change in the SLM model is consistent with the measured data. At finally, from the fundamental diagram, the relationship between traffic ability and the lengths of ships is explored. The number of ships in the waterway declines when the proportion of large ships increases.
Lovreglio, Ruggiero; Ronchi, Enrico; Nilsson, Daniel
2015-11-01
The formulation of pedestrian floor field cellular automaton models is generally based on hypothetical assumptions to represent reality. This paper proposes a novel methodology to calibrate these models using experimental trajectories. The methodology is based on likelihood function optimization and allows verifying whether the parameters defining a model statistically affect pedestrian navigation. Moreover, it allows comparing different model specifications or the parameters of the same model estimated using different data collection techniques, e.g. virtual reality experiment, real data, etc. The methodology is here implemented using navigation data collected in a Virtual Reality tunnel evacuation experiment including 96 participants. A trajectory dataset in the proximity of an emergency exit is used to test and compare different metrics, i.e. Euclidean and modified Euclidean distance, for the static floor field. In the present case study, modified Euclidean metrics provide better fitting with the data. A new formulation using random parameters for pedestrian cellular automaton models is also defined and tested.
Asynchronous cellular automaton-based neuron: theoretical analysis and on-FPGA learning.
Matsubara, Takashi; Torikai, Hiroyuki
2013-05-01
A generalized asynchronous cellular automaton-based neuron model is a special kind of cellular automaton that is designed to mimic the nonlinear dynamics of neurons. The model can be implemented as an asynchronous sequential logic circuit and its control parameter is the pattern of wires among the circuit elements that is adjustable after implementation in a field-programmable gate array (FPGA) device. In this paper, a novel theoretical analysis method for the model is presented. Using this method, stabilities of neuron-like orbits and occurrence mechanisms of neuron-like bifurcations of the model are clarified theoretically. Also, a novel learning algorithm for the model is presented. An equivalent experiment shows that an FPGA-implemented learning algorithm enables an FPGA-implemented model to automatically reproduce typical nonlinear responses and occurrence mechanisms observed in biological and model neurons.
A refined and dynamic cellular automaton model for pedestrian-vehicle mixed traffic flow
Liu, Mianfang; Xiong, Shengwu
2016-12-01
Mixed traffic flow sharing the “same lane” and having no discipline on road is a common phenomenon in the developing countries. For example, motorized vehicles (m-vehicles) and nonmotorized vehicles (nm-vehicles) may share the m-vehicle lane or nm-vehicle lane and pedestrians may share the nm-vehicle lane. Simulating pedestrian-vehicle mixed traffic flow consisting of three kinds of traffic objects: m-vehicles, nm-vehicles and pedestrians, can be a challenge because there are some erratic drivers or pedestrians who fail to follow the lane disciplines. In the paper, we investigate various moving and interactive behavior associated with mixed traffic flow, such as lateral drift including illegal lane-changing and transverse crossing different lanes, overtaking and forward movement, and propose some new moving and interactive rules for pedestrian-vehicle mixed traffic flow based on a refined and dynamic cellular automaton (CA) model. Simulation results indicate that the proposed model can be used to investigate the traffic flow characteristic in a mixed traffic flow system and corresponding complicated traffic problems, such as, the moving characteristics of different traffic objects, interaction phenomenon between different traffic objects, traffic jam, traffic conflict, etc., which are consistent with the actual mixed traffic system. Therefore, the proposed model provides a solid foundation for the management, planning and evacuation of the mixed traffic flow.
A self-modifying cellular automaton model of historical urbanization in the San Francisco Bay area
Clarke, K.C.; Hoppen, S.; Gaydos, L.
1997-01-01
In this paper we describe a cellular automaton (CA) simulation model developed to predict urban growth as part of a project for estimating the regional and broader impact of urbanization on the San Francisco Bay area's climate. The rules of the model are more complex than those of a typical CA and involve the use of multiple data sources, including topography, road networks, and existing settlement distributions, and their modification over time. In addition, the control parameters of the model are allowed to self-modify: that is, the CA adapts itself to the circumstances it generates, in particular, during periods of rapid growth or stagnation. In addition, the model was written to allow the accumulation of probabilistic estimates based on Monte Carlo methods. Calibration of the model has been accomplished by the use of historical maps to compare model predictions of urbanization, based solely upon the distribution in year 1900, with observed data for years 1940, 1954, 1962, 1974, and 1990. The complexity of this model has made calibration a particularly demanding step. Lessons learned about the methods, measures, and strategies developed to calibrate the model may be of use in other environmental modeling contexts. With the calibration complete, the model is being used to generate a set of future scenarios for the San Francisco Bay area along with their probabilities based on the Monte Carlo version of the model. Animated dynamic mapping of the simulations will be used to allow visualization of the impact of future urban growth.
Simple cellular automaton model for traffic breakdown, highway capacity, and synchronized flow.
Kerner, Boris S; Klenov, Sergey L; Schreckenberg, Michael
2011-10-01
We present a simple cellular automaton (CA) model for two-lane roads explaining the physics of traffic breakdown, highway capacity, and synchronized flow. The model consists of the rules "acceleration," "deceleration," "randomization," and "motion" of the Nagel-Schreckenberg CA model as well as "overacceleration through lane changing to the faster lane," "comparison of vehicle gap with the synchronization gap," and "speed adaptation within the synchronization gap" of Kerner's three-phase traffic theory. We show that these few rules of the CA model can appropriately simulate fundamental empirical features of traffic breakdown and highway capacity found in traffic data measured over years in different countries, like characteristics of synchronized flow, the existence of the spontaneous and induced breakdowns at the same bottleneck, and associated probabilistic features of traffic breakdown and highway capacity. Single-vehicle data derived in model simulations show that synchronized flow first occurs and then self-maintains due to a spatiotemporal competition between speed adaptation to a slower speed of the preceding vehicle and passing of this slower vehicle. We find that the application of simple dependences of randomization probability and synchronization gap on driving situation allows us to explain the physics of moving synchronized flow patterns and the pinch effect in synchronized flow as observed in real traffic data.
Cellular automaton model of crowd evacuation inspired by slime mould
Kalogeiton, V. S.; Papadopoulos, D. P.; Georgilas, I. P.; Sirakoulis, G. Ch.; Adamatzky, A. I.
2015-04-01
In all the living organisms, the self-preservation behaviour is almost universal. Even the most simple of living organisms, like slime mould, is typically under intense selective pressure to evolve a response to ensure their evolution and safety in the best possible way. On the other hand, evacuation of a place can be easily characterized as one of the most stressful situations for the individuals taking part on it. Taking inspiration from the slime mould behaviour, we are introducing a computational bio-inspired model crowd evacuation model. Cellular Automata (CA) were selected as a fully parallel advanced computation tool able to mimic the Physarum's behaviour. In particular, the proposed CA model takes into account while mimicking the Physarum foraging process, the food diffusion, the organism's growth, the creation of tubes for each organism, the selection of optimum tube for each human in correspondence to the crowd evacuation under study and finally, the movement of all humans at each time step towards near exit. To test the model's efficiency and robustness, several simulation scenarios were proposed both in virtual and real-life indoor environments (namely, the first floor of office building B of the Department of Electrical and Computer Engineering of Democritus University of Thrace). The proposed model is further evaluated in a purely quantitative way by comparing the simulation results with the corresponding ones from the bibliography taken by real data. The examined fundamental diagrams of velocity-density and flow-density are found in full agreement with many of the already published corresponding results proving the adequacy, the fitness and the resulting dynamics of the model. Finally, several real Physarum experiments were conducted in an archetype of the aforementioned real-life environment proving at last that the proposed model succeeded in reproducing sufficiently the Physarum's recorded behaviour derived from observation of the aforementioned
Cellular Automaton Rule 184++C A Simple Model for the Complex Dynamics of Various Particles Flow
Awazu, A
1999-01-01
A cellular automaton named Rule 184++C is proposed as a meta-model to investigate the flow of various complex particles. In this model, unlike the granular pipe flow and the traffic flow, not only the free-jam phase transition but also the free-intermediate, the intermediate-jam, and the dilute-dense phase transitions appear. Moreover, the freezing phenomena appear if the system contains two types of different particles.
A Real-Space Cellular Automaton Laboratory for the modeling of complex dunefields
Rozier, Olivier; Narteau, Clement
2013-04-01
Using applications in the physics of sand dunes, we explore the capabilities of a Real Space Cellular Automaton Laboratory (ReSCAL), a generator of 3D stochastic cellular automaton stochastic cellular automaton models with continuous time. The objective of this software is to develop interdisciplinary research collaboration to investigate the dynamics of complex systems. In the vast majority of numerical models, any point in space is entirely characterized by a local set of physical variables (e. g. temperature, pressure, velocity) that are recalculated over time according to some predetermined set of fundamental laws. However, there is not always a satisfactory theoretical framework from which we can try to quantify the overall dynamics of the system. For this reason, we prefer concentrate on features of organization and ReSCAL is entirely constructed from a finite number of discrete states that represent the different phases of matter involved in the system under consideration. Then, an elementary cell is a real-space representation of the physical environment. Pairs of nearest neighbor cells are called doublets and each individual physical process is associated with a set of doublet transitions and a characteristic transition rate. Using a modular approach, we show how it is possible to model and combine a wide range of physical, chemical and/or anthropological processes. As an example, we discuss different dune morphologies with respect to rotating wind conditions.
Directory of Open Access Journals (Sweden)
Burbelko A. A.
2007-01-01
Full Text Available Modelling of solidification process by the method of cellular automaton (CA requires determination of geometrical characteristics of the interface, i.e. of its direction and curvature. In previous studies the authors proposed a method to reduce the well-known effect of an artificial symmetry of the simulation results caused by the anisotropy of the CA computation grid (e.g. a preferred growth of the main dendrite arms along the grid lines or at an angle of 45° in the case of grids with square cells. The aim was achieved by application of the developed methods of computation of the transformation rate and front direction. In this study the authors examined the problem of an accuracy of the computations of an interface curvature. The obtained results show us that the error of the curvature computation introduced by some well-known methods exceeds by 100% a nominal value of this parameter. A method to estimate the accuracy of the applied solution has been proposed. Practical application of the proposed tests enables selection of a best solution, including the authors' own solutions, thus considerably improving an accuracy of the solidification modelling by the method of CA.
The Investigation of the Traffic Flow Behavior in Tollbooths Using Cellular Automaton Model
Jetto, K.; Ez-Zahraouy, H.; Benyoussef, A.
Tollbooths are used to collect tolls and to control traffic flow. However, the presence of these tollbooths will slow down traffic, especially in heavily traveled roads. As a consequence, drivers and goods will spend more time and fuel waiting in a long queue. Unfortunately, there are a few papers in the literature, which have been addressed the effect of tollbooths on the traffic flow; whereas in this paper is, the properties of traffic flow inside the tollbooths are investigated. The proposed cellular automaton traffic model, with open boundaries, is based on some changing lane rules, which are inspired on the situations inside the toll plaza. The vehicles enter the plaza with an injecting rate α, and they leave with an extracting rate β, which is inversely proportional to the time service Tw. The simulation results show the existence of three phases in the phase diagram (α, β), namely: the low density phase, the congested phase, and the jamming phase. Furthermore, it is found that the vehicles does not spend the same time Tm in the plaza, even if they have the same time service. This analysis states clearly that the existence of the congested phase and the fluctuation Tm are due to the non-zero values of the probability P of changing the lane. Such phenomena disappear when P = 0, i.e., the drivers move without changing their lane. In other words, the human behavior (spontaneous changing lanes) is responsible for the congestion observed in the tollbooth.
Modeling of aluminum-silicon irregular eutectic growth by cellular automaton model
Directory of Open Access Journals (Sweden)
Rui Chen
2016-03-01
Full Text Available Due to the extensive application of Al-Si alloys in the automotive and aerospace industries as structural components, an understanding of their microstructural formation, such as dendrite and (Al+Si eutectic, is of great importance to control the desirable microstructure, so as to modify the performance of castings. Since previous major themes of microstructural simulation are dendrite and regular eutectic growth, few efforts have been paid to simulate the irregular eutectic growth. Therefore, a multiphase cellular automaton (CA model is developed and applied to simulate the time-dependent Al-Si irregular eutectic growth. Prior to model establishment, related experiments were carried out to investigate the influence of cooling rate and Sr modification on the growth of eutectic Si. This CA model incorporates several aspects, including growth algorithms and nucleation criterion, to achieve the competitive and cooperative growth mechanism for nonfaceted-faceted Al-Si irregular eutectic. The growth kinetics considers thermal undercooling, constitutional undercooling, and curvature undercooling, as well as the anisotropic characteristic of eutectic Si growth. The capturing rule takes into account the effects of modification on the silicon growth behaviors. The simulated results indicate that for unmodified alloy, the higher eutectic undercooling results in the higher eutectic growth velocity, and a more refined eutectic microstructure as well as narrower eutectic lamellar spacing. For modified alloy, the eutectic silicon tends to be obvious fibrous morphology and the morphology of eutectic Si is determined by both chemical modifier and cooling rate. The predicted microstructure of Al-7Si alloy under different solidification conditions shows that this proposed model can successfully reproduce both dendrite and eutectic microstructures.
Directory of Open Access Journals (Sweden)
Jacqueline Palmari
1997-01-01
Full Text Available A well‐suited model to simulate cellular population dynamics is the two‐dimensional cellular automaton model, which consists of a lattice of sites, the value ai,j of each site being updated in discrete time steps according to an identical deterministic rule depending on a neighbourhood of sites around it. A cellular automaton is described which mimics cell population proliferation by replacing the site values by the age and the cycle phase of cells. The model takes into account the size of the cells. It is used to simulate the proliferation of the human breast cancer cell line MCF‐7 and the results of the simulation are compared with experimental data obtained from a light microscopic image analysis of the proliferation process. The initial configuration of the cellular automaton is obtained from the discretization of the results of the initial stage of the image processing. After each day of proliferation the pattern obtained from the simulation is compared to the experimental result of the corresponding image analysis. The comparison is made from a topographical point of view through the concept of the minimal spanning tree graph. The agreement between experiment and model is a good starting point to complex models such as cell proliferation under growth effectors or drugs.
Variable entangling in a quantum prisoner's dilemma cellular automaton
Alonso-Sanz, Ramón
2015-01-01
The effect of variable entangling on the dynamics of a spatial quantum formulation of the iterated prisoner's dilemma game is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. The effect of spatial structure is assessed when allowing the players to adopt quantum and classical strategies, both in the two- and three-parameter strategy spaces.
Cellular automaton modelling of lightning-induced and man made forest fires
Krenn, R.; Hergarten, S.
2009-10-01
The impact of forest fires on nature and civilisation is conflicting: on one hand, they play an irreplaceable role in the natural regeneration process, but on the other hand, they come within the major natural hazards in many regions. Their frequency-area distributions show power-law behaviour with scaling exponents α in a quite narrow range, relating wildfire research to the theoretical framework of self-organised criticality. Examples of self-organised critical behaviour can be found in computer simulations of simple cellular automaton models. The established self-organised critical Drossel-Schwabl forest fire model is one of the most widespread models in this context. Despite its qualitative agreement with event-size statistics from nature, its applicability is still questioned. Apart from general concerns that the Drossel-Schwabl model apparently oversimplifies the complex nature of forest dynamics, it significantly overestimates the frequency of large fires. We present a modification of the model rules that distinguishes between lightning-induced and man made forest fires and enables a systematic increase of the scaling exponent α by approximately 1/3. In addition, combined simulations using both the original and the modified model rules predict a dependence of the overall event-size distribution on the ratio of lightning induced and man made fires as well as a splitting of their partial distributions. Lightning is identified as the dominant mechanism in the regime of the largest fires. The results are confirmed by the analysis of the Canadian Large Fire Database and suggest that lightning-induced and man made forest fires cannot be treated separately in wildfire modelling, hazard assessment and forest management.
2017-01-01
Mathematical models of cardiac electrical excitation are increasingly complex, with multiscale models seeking to represent and bridge physiological behaviours across temporal and spatial scales. The increasing complexity of these models makes it computationally expensive to both evaluate long term (more than 60 s) behaviour and determine sensitivity of model outputs to inputs. This is particularly relevant in models of atrial fibrillation (AF), where individual episodes last from seconds to days, and interepisode waiting times can be minutes to months. Potential mechanisms of transition between sinus rhythm and AF have been identified but are not well understood, and it is difficult to simulate AF for long periods of time using state-of-the-art models. In this study, we implemented a Moe-type cellular automaton on a novel, topologically equivalent surface geometry of the left atrium. We used the model to simulate stochastic initiation and spontaneous termination of AF, arising from bursts of spontaneous activation near pulmonary veins. The simplified representation of atrial electrical activity reduced computational cost, and so permitted us to investigate AF mechanisms in a probabilistic setting. We computed large numbers (approx. 105) of sample paths of the model, to infer stochastic initiation and termination rates of AF episodes using different model parameters. By generating statistical distributions of model outputs, we demonstrated how to propagate uncertainties of inputs within our microscopic level model up to a macroscopic level. Lastly, we investigated spontaneous termination in the model and found a complex dependence on its past AF trajectory, the mechanism of which merits future investigation. PMID:28356539
A Modified Cellular Automaton Model for Traffic Flow%一种改进的交通流元胞自动机模型
Institute of Scientific and Technical Information of China (English)
葛红霞; 董力耘; 雷丽; 戴世强
2004-01-01
A modified cellular automaton model for traffic flow was proposed.A novel concept about the changeable security gap was introduced and a parameter related to the variable security gap was determined.The fundamental diagram obtained by simulation shows that the maximum flow more approaches to the observed data than that of the NaSch model,indicating that the presented model is more reasonable and realistic.
Modeling dynamics of HIV infected cells using stochastic cellular automaton
Precharattana, Monamorn; Triampo, Wannapong
2014-08-01
Ever since HIV was first diagnosed in human, a great number of scientific works have been undertaken to explore the biological mechanisms involved in the infection and progression of the disease. Several cellular automata (CA) models have been introduced to gain insights into the dynamics of the disease progression but none of them has taken into account effects of certain immune cells such as the dendritic cells (DCs) and the CD8+ T lymphocytes (CD8+ T cells). In this work, we present a CA model, which incorporates effects of the HIV specific immune response focusing on the cell-mediated immunities, and investigate the interaction between the host immune response and the HIV infected cells in the lymph nodes. The aim of our work is to propose a model more realistic than the one in Precharattana et al. (2010) [10], by incorporating roles of the DCs, the CD4+ T cells, and the CD8+ T cells into the model so that it would reproduce the HIV infection dynamics during the primary phase of HIV infection.
A Cellular Automaton Model for Heterogeneous and Incosistent Driver Behavior in Urban Traffic
Institute of Scientific and Technical Information of China (English)
LIUMing-Zhe; ZHAO Shi-Bo; WANG Rui-Li
2012-01-01
In this paper a cellular automaton model is proposed to describe driver behavior at a single-lane urban roundabout. Driver behavior has been considered as heterogeneous and inconsistent. Most traffic papers in the literature just discussed heterogeneous driver behavior, to our best knowledge. Two truncated Caussian distributions are used to model heterogeneous and inconsistent driver behavior, respectively. The physical meanings of two truncated distributions are indicated. This method may help enhance a better understanding of driver behavior at roundabout traffic, and even possibly provide references for roundabout design and management.
On a cellular automaton with time delay for modelling cancer tumors
Energy Technology Data Exchange (ETDEWEB)
Iarosz, K C; Martins, C C; Batista, A M [Departamento de Matematica e EstatIstica, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Viana, R L; Lopes, S R [Departamento de Fisica, Universidade Federal do Parana, 81531-990, Curitiba, PR (Brazil); Caldas, I L [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66316, 05315-970, Sao Paulo, SP (Brazil); Penna, T J P, E-mail: antoniomarcosbatista@gmail.com [Instituto de Fisica, Universidade Federal Fluminense, 24210-340, Niteroi, RJ (Brazil)
2011-03-01
In this work we considered cellular automaton model with time delay. Time delay included in this model reflects the delay between the time in which the site is affected and the time in which its variable is updated. We analyzed the effect of the rules on the dynamics through the cluster counting. According to this cluster counting, the dynamics behavior is investigated. We verified periodic oscillations same as delay differential equation. We also studied the relation between the time delay in the cell cycle and the time to start the metastasis, using suitable numerical diagnostics.
Finite-size scaling relations for a four-dimensional Ising model on Creutz cellular automatons
Merdan, Z.; Güzelsoy, E.
2011-06-01
The four-dimensional Ising model is simulated on Creutz cellular automatons using finite lattices with linear dimensions 4 ≤ L ≤ 8. The temperature variations and finite-size scaling plots of the specific heat and the Binder parameter verify the theoretically predicted expression near the infinite lattice critical temperature for 7, 14, and 21 independent simulations. Approximate values for the critical temperature of the infinite lattice of Tc(∞) = 6.6965(35), 6.6961(30), 6.6960(12), 6.6800(3), 6.6801(2), 6.6802(1) and 6.6925(22) (without the logarithmic factor), 6.6921(22) (without the logarithmic factor), 6.6909(2) (without the logarithmic factor), 6.6822(13) (with the logarithmic factor), 6.6819(11) (with the logarithmic factor), and 6.6808(8) (with the logarithmic factor) are obtained from the intersection points of the specific heat curves, the Binder parameter curves, and straight line fits of specific heat maxima for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the results, 6.6802(1) and 6.6808(8), are in very good agreement with the results of a series expansion of Tc(∞), 6.6817(15) and 6.6802(2), the dynamic Monte Carlo value Tc(∞) = 6.6803(1), the cluster Monte Carlo value Tc(∞) = 6.680(1), and the Monte Carlo value using the Metropolis-Wolff cluster algorithm Tc(∞) = 6.6802632 ± 5 . 10-5. The average values calculated for the critical exponent of the specific heat are α =- 0.0402(15), - 0.0393(12), - 0.0391(11) with 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the result, α =- 0.0391(11), agrees with the series expansions result, α =- 0.12 ± 0.03 and the Monte Carlo result using the Metropolis-Wolff cluster algorithm, α ≥ 0 ± 0.04. However, α =- 0.0391(11) is inconsistent with the renormalization group prediction of α = 0.
An Option Pricing Model Based on Cellular Automaton%基于元胞自动机的期权定价模型
Institute of Scientific and Technical Information of China (English)
李捷
2011-01-01
Option pricing is one of the most difficult problems in financial research. The key to the problem is how to simulate the randomness of the underlying asset price. This paper designs and implements an option pricing model based on the cellular automaton, which treats market participants as the cells in the cellular automaton. The model uses cellular automaton rules to simulate the interactions between traders and the changes of underlying asset prices. The paper compares the output data of the model with the calculation results of the Black-Scholes model, tests the normality of the model＇s output data, and finds that the option pricing model based on the cellular automaton is not only feasible, but also more effective than the Black-Scholes model.%针对期权定价难于模拟基础资产价格波动随机性的问题，设计了基于元胞自动机的期权定价模型．该模型将市场参与者看作一个个的元胞，使用元胞规则来模拟金融市场中交易者之间的交互行为。从而在总体上模拟出基础资产价格的变化．比较了模型产出的数据和Black-Scholes模型的计算结果，检验了模型产出数据的正态性，发现基于元胞自动机的期权定价模型不仅具有可行性，而且比Black-Scholes模型更有效．
Path-integral solution of the one-dimensional Dirac quantum cellular automaton
Energy Technology Data Exchange (ETDEWEB)
D' Ariano, Giacomo Mauro [QUIT group, Dipartimento di Fisica, via Bassi 6, Pavia, 27100 (Italy); INFN Gruppo IV, Sezione di Pavia, via Bassi 6, Pavia, 27100 (Italy); Mosco, Nicola [QUIT group, Dipartimento di Fisica, via Bassi 6, Pavia, 27100 (Italy); Perinotti, Paolo [QUIT group, Dipartimento di Fisica, via Bassi 6, Pavia, 27100 (Italy); INFN Gruppo IV, Sezione di Pavia, via Bassi 6, Pavia, 27100 (Italy); Tosini, Alessandro [QUIT group, Dipartimento di Fisica, via Bassi 6, Pavia, 27100 (Italy)
2014-09-05
Quantum cellular automata, which describe the discrete and exactly causal unitary evolution of a lattice of quantum systems, have been recently considered as a fundamental approach to quantum field theory and a linear automaton for the Dirac equation in one dimension has been derived. In the linear case a quantum cellular automaton is isomorphic to a quantum walk and its evolution is conveniently formulated in terms of transition matrices. The semigroup structure of the matrices leads to a new kind of discrete path-integral, different from the well known Feynman checkerboard one, that is solved analytically in terms of Jacobi polynomials of the arbitrary mass parameter. - Highlights: • Discrete path integral formulation of linear QCAs in terms of transition matrices. • Derivation of the analytical solution for the one dimensional Dirac QCA. • Solution given in terms of Jacobi polynomials versus the arbitrary mass parameter. • The discrete paths and the transition matrices of the Dirac QCA are binary encoded. • Paths are grouped in equivalence classes according to their overall transition matrix.
Reprint of Infinity computations in cellular automaton forest-fire model
Iudin, D. I.; Sergeyev, Ya. D.; Hayakawa, M.
2015-04-01
Recently a number of traditional models related to the percolation theory has been considered by means of a new computational methodology that does not use Cantor's ideas and describes infinite and infinitesimal numbers in accordance with the principle 'The whole is greater than the part' (Euclid's Common Notion 5). Here we apply the new arithmetic to a cellular automaton forest-fire model which is connected with the percolation methodology and in some sense combines the dynamic and the static percolation problems and under certain conditions exhibits critical fluctuations. It is well known that there exist two versions of the model: real forest-fire model where fire catches adjacent trees in the forest in the step by step manner and simplified version with instantaneous combustion. Using new approach we observe that in both situations we deal with the same model but with different time resolution. We show that depending on the "microscope" we use the same cellular automaton forest-fire model reveals either instantaneous forest combustion or step by step firing. By means of the new approach it was also observed that as far as we choose an infinitesimal tree growing rate and infinitesimal ratio between the ignition probability and the growth probability we determine the measure or extent of the system size infinity that provides the criticality of the system dynamics. Correspondent inequalities for grosspowers are derived.
Shi, Xiao-Qiu; Wu, Yi-Qi; Li, Hong; Zhong, Rui
2007-11-01
Two-dimensional cellular automaton model has been broadly researched for traffic flow, as it reveals the main characteristics of the traffic networks in cities. Based on the BML models, a first-order phase transition occurs between the low-density moving phase in which all cars move at maximal speed and the high-density jammed phase in which all cars are stopped. However, it is not a physical result of a realistic system. We propose a new traffic rule in a two-dimensional traffic flow model containing road sections, which reflects that a car cannot enter into a road crossing if the road section in front of the crossing is occupied by another car. The simulation results reveal a second-order phase transition that separates the free flow phase from the jammed phase. In this way the system will not be entirely jammed (“don’t block the box” as in New York City).
Maerivoet, S; Immers, B; De Moor, B; Maerivoet, Sven; Logghe, Steven; Immers, Ben; Moor, Bart De
2005-01-01
In this paper, we describe a relation between a microscopic traffic cellular automaton (TCA) model (i.e., the stochastic TCA model of Nagel and Schreckenberg) and the macroscopic first-order hydrodynamic model of Lighthill, Whitham, and Richards (LWR). The innovative aspect of our approach, is that we explicitly derive the LWR's fundamental diagram directly from the STCA's rule set, by assuming a stationarity condition that converts the STCA's rules into a set of linear inequalities. In turn, these constraints define the shape of the fundamental diagram, which is then specified to the LWR model. Application of our methodology to a simulation case study, allows us to compare the tempo-spatial behavior of both models. Our results indicate that, in the presence of noise, the capacity flows in the derived fundamental diagram are overestimations of those of the STCA model. Directly specifying the STCA's capacity flows to the LWR fundamental diagram, effectively remedies most of the mismatches between both approach...
A Cellular Automaton Model for Tumor Dormancy: Emergence of a Proliferative Switch
Chen, Duyu; Torquato, Salvatore
2014-01-01
Malignant cancers that lead to fatal outcomes for patients may remain dormant for very long periods of time. Although individual mechanisms such as cellular dormancy, angiogenic dormancy and immunosurveillance have been proposed, a comprehensive understanding of cancer dormancy and the "switch" from a dormant to a proliferative state still needs to be strengthened from both a basic and clinical point of view. Computational modeling enables one to explore a variety of scenarios for possible but realistic microscopic dormancy mechanisms and their predicted outcomes. The aim of this paper is to devise such a predictive computational model of dormancy with an emergent "switch" behavior. Specifically, we generalize a previous cellular automaton (CA) model for proliferative growth of solid tumor that now incorporates a variety of cell-level tumor-host interactions and different mechanisms for tumor dormancy, for example the effects of the immune system. Our new CA rules induce a natural "competition" between the tu...
fA cellular automaton model of crystalline cellulose hydrolysis by cellulases
Directory of Open Access Journals (Sweden)
Little Bryce A
2011-10-01
Full Text Available Abstract Background Cellulose from plant biomass is an abundant, renewable material which could be a major feedstock for low emissions transport fuels such as cellulosic ethanol. Cellulase enzymes that break down cellulose into fermentable sugars are composed of different types - cellobiohydrolases I and II, endoglucanase and β-glucosidase - with separate functions. They form a complex interacting network between themselves, soluble hydrolysis product molecules, solution and solid phase substrates and inhibitors. There have been many models proposed for enzymatic saccharification however none have yet employed a cellular automaton approach, which allows important phenomena, such as enzyme crowding on the surface of solid substrates, denaturation and substrate inhibition, to be considered in the model. Results The Cellulase 4D model was developed de novo taking into account the size and composition of the substrate and surface-acting enzymes were ascribed behaviors based on their movements, catalytic activities and rates, affinity for, and potential for crowding of, the cellulose surface, substrates and inhibitors, and denaturation rates. A basic case modeled on literature-derived parameters obtained from Trichoderma reesei cellulases resulted in cellulose hydrolysis curves that closely matched curves obtained from published experimental data. Scenarios were tested in the model, which included variation of enzyme loadings, adsorption strengths of surface acting enzymes and reaction periods, and the effect on saccharide production over time was assessed. The model simulations indicated an optimal enzyme loading of between 0.5 and 2 of the base case concentrations where a balance was obtained between enzyme crowding on the cellulose crystal, and that the affinities of enzymes for the cellulose surface had a large effect on cellulose hydrolysis. In addition, improvements to the cellobiohydrolase I activity period substantially improved overall
2D cellular automaton model for the evolution of active region coronal plasmas
Fuentes, Marcelo López
2016-01-01
We study a 2D cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their footpoints by photospheric motions. The magnetic stress accumulated between neighbor strands is released in sudden reconnection events or nanoflares that heat the plasma. We combine the CA model with the Enthalpy Based Thermal Evolution of Loops (EBTEL) model to compute the response of the plasma to the heating events. Using the known response of the XRT telescope on board Hinode we also obtain synthetic data. The model obeys easy to understand scaling laws relating the output (nanoflare energy, temperature, density, intensity) to the input parameters (field strength, strand length, critical misalignment angle). The nanoflares have a power-law distribution with a universal slope of -2.5, independent of the input parameters. The repetition frequency of nanoflares, expressed in t...
Synchronized Flow in a Cellular Automaton Model with Time Headway Dependent Randomization
Institute of Scientific and Technical Information of China (English)
CHEN Tao; JIA Bin; LI Xin-Gang; JIANG Rui; GAO Zi-You
2008-01-01
@@ We propose another possible mechanism of synchronized flow, I.e. That a time headway dependent randomization can exhibit synchronized flow. Based on this assumption, we present a new cellular automaton (CA) model for traffic flow, in which randomization effect is enhanced with the decrease of time headway. We study fundamental diagram and spatial-temporal diagrams of the model and perform microscopic analysis of time series data, which shows the model could reproduce synchronized flow as expected. It is also shown that a spontaneous transition from synchronized flow to jam could be observed by incorporating slow-to-start effect into the model. We expect that our work could contribute to the understanding of the real origin of synchronized flow.
Cellular automaton modeling of ductile iron microstructure in the thin wall
Directory of Open Access Journals (Sweden)
A.A. Burbelko
2011-10-01
Full Text Available The mathematical model of the globular eutectic solidification in 2D was designed. Proposed model is based on the Cellular Automaton Finite Differences (CA-FD calculation method. Model has been used for studies of the primary austenite and of globular eutectic grains growth during the solidification of the ductile iron with different carbon equivalent in the thin wall casting. Model takes into account, among other things, non-uniform temperature distribution in the casting wall cross-section, kinetics of the austenite and graphite grains nucleation, and non-equilibrium nature of the interphase boundary migration. Solidification of the DI with different carbon equivalents was analyzed. Obtained results were compared with the solidification path calculated by CALPHAD method.
A Real Space Cellular Automaton Laboratory (ReSCAL) to analyze complex geophysical systems
Rozier, O.; Narteau, C.
2012-04-01
The Real Space Cellular Automaton Laboratory (ReSCAL) is a generator of 3D multiphysics, markovian and stochastic cellular automata with continuous time. The objective of this new software released under a GNU licence is to develop interdisciplinary research collaboration to investigate the dynamics of complex geophysical systems. In a vast majority of cases, a numerical model is a set of physical variables (temperature, pressure, velocity, etc...) that are recalculated over time according to some predetermined rules or equations. Then, any point in space is entirely characterized by a local set of parameters. This is not the case in ReSCAL where the only local variable is a state-parameter that represent the different phases involved in the problem. An elementary cell represent a given volume of real-space. Pairs of nearest neighbour cells are called doublet. For each individual physical process that we take into account, there is a set of doublet transitions. Using this approach we can model a wide range of physical-chemical or anthropological processes. Here, we present different ingredients of ReSCAL using published applications in geosciences (Narteau et al. 2001 and 2009). We also show how ReSCAL can be developped and used across many displines in geophysics and physical geography. Supplementary informations: Sources files of ReSCAL can be download on http://www.ipgp.fr/~rozier/ReSCAL/rescal-en.html
Transition between immune and disease states in a cellular automaton model of clonal immune response
Bezzi, M; Ruffo, S; Seiden, P E; Bezzi, Michele; Celada, Franco; Ruffo, Stefano; Seiden, Philip E.
1997-01-01
In this paper we extend the Celada-Seiden (CS) model of the humoral immune response to include infectious virus and cytotoxic T lymphocytes (cellular response). The response of the system to virus involves a competition between the ability of the virus to kill the host cells and the host's ability to eliminate the virus. We find two basins of attraction in the dynamics of this system, one is identified with disease and the other with the immune state. There is also an oscillating state that exists on the border of these two stable states. Fluctuations in the population of virus or antibody can end the oscillation and drive the system into one of the stable states. The introduction of mechanisms of cross-regulation between the two responses can bias the system towards one of them. We also study a mean field model, based on coupled maps, to investigate virus-like infections. This simple model reproduces the attractors for average populations observed in the cellular automaton. All the dynamical behavior connect...
Stability Analysis of a Hybrid Cellular Automaton Model of Cell Colony Growth
Gerlee, P
2007-01-01
Cell colonies of bacteria, tumour cells and fungi, under nutrient limited growth conditions, exhibit complex branched growth patterns. In order to investigate this phenomenon we present a simple hybrid cellular automaton model of cell colony growth. In the model the growth of the colony is limited by a nutrient that is consumed by the cells and which inhibits cell division if it falls below a certain threshold. Using this model we have investigated how the nutrient consumption rate of the cells affects the growth dynamics of the colony. We found that for low consumption rates the colony takes on a Eden-like morphology, while for higher consumption rates the morphology of the colony is branched with a fractal geometry. These findings are in agreement with previous results, but the simplicity of the model presented here allows for a linear stability analysis of the system. By observing that the local growth of the colony is proportional to the flux of the nutrient we derive an approximate dispersion relation fo...
a 2-DIMENSIONAL Cellular Automaton for Agents Moving from Origins to Destinations
Moussa, Najem
We develop a two-dimensional cellular automaton (CA) as a simple model for agents moving from origins to destinations. Each agent moves towards an empty neighbor site corresponding to the minimal distance to its destination. The stochasticity or noise (p) is introduced in the model dynamics, through the uncertainty in estimating the distance from the destination. The friction parameter "μ" is also introduced to control the probability that movement of all involved agents to the same site (conflict) is denied at each time step. This model displays two states; namely the freely moving and the jamming state. If μ is large and p is low, the system is in the jamming state even if the density is low. However, if μ is large and p is high, a freely moving state takes place whenever the density is low. The cluster size and the travel time distributions in the two states are studied in detail. We find that only very small clusters are present in the freely moving state, while the jamming state displays a bimodal distribution. At low densities, agents can take a very long time to reach their destinations if μ is large and p is low (jamming state); but long travel times are suppressed if p becomes large (freely moving state).
Stable oscillations of a predator-prey probabilistic cellular automaton: a mean-field approach
Energy Technology Data Exchange (ETDEWEB)
Tome, Tania; Carvalho, Kelly C de [Instituto de FIsica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo (Brazil)
2007-10-26
We analyze a probabilistic cellular automaton describing the dynamics of coexistence of a predator-prey system. The individuals of each species are localized over the sites of a lattice and the local stochastic updating rules are inspired by the processes of the Lotka-Volterra model. Two levels of mean-field approximations are set up. The simple approximation is equivalent to an extended patch model, a simple metapopulation model with patches colonized by prey, patches colonized by predators and empty patches. This approximation is capable of describing the limited available space for species occupancy. The pair approximation is moreover able to describe two types of coexistence of prey and predators: one where population densities are constant in time and another displaying self-sustained time oscillations of the population densities. The oscillations are associated with limit cycles and arise through a Hopf bifurcation. They are stable against changes in the initial conditions and, in this sense, they differ from the Lotka-Volterra cycles which depend on initial conditions. In this respect, the present model is biologically more realistic than the Lotka-Volterra model.
Directory of Open Access Journals (Sweden)
Zhenke Luo
2014-12-01
Full Text Available Mixed traffic flow composed of autos and non-autos widely exists in developing countries and areas. To investigate the operational characteristics of the mixed traffic flow consisting of vehicles in different types (large vehicles, cas, and bicycles, we develop a cellular automaton model to replicate the travel behaviors on a bi-directional road segment with respect to the physical and mechanic ftures of différent vehicle types. By implementing the eesential parameters calibrated through the field data collection, a numerical study is carried out considering the variation in volume, density, and velocity with different compositions of mixed traffic flows. The primary findings include: the average velocity of traffic flow and total volume decrease 60% and 30% after incorporating 10% bicycles, respectively; the phenomenon of double-summit in terms of the total volume appears when the proportion of bicycle is beyond 60%; the maximal total volume starts to recover when the proportion of bicycle is higher than 10 %.
CellLab-CTS 2015: continuous-time stochastic cellular automaton modeling using Landlab
Tucker, Gregory E.; Hobley, Daniel E. J.; Hutton, Eric; Gasparini, Nicole M.; Istanbulluoglu, Erkan; Adams, Jordan M.; Siddartha Nudurupati, Sai
2016-02-01
CellLab-CTS 2015 is a Python-language software library for creating two-dimensional, continuous-time stochastic (CTS) cellular automaton models. The model domain consists of a set of grid nodes, with each node assigned an integer state code that represents its condition or composition. Adjacent pairs of nodes may undergo transitions to different states, according to a user-defined average transition rate. A model is created by writing a Python code that defines the possible states, the transitions, and the rates of those transitions. The code instantiates, initializes, and runs one of four object classes that represent different types of CTS models. CellLab-CTS provides the option of using either square or hexagonal grid cells. The software provides the ability to treat particular grid-node states as moving particles, and to track their position over time. Grid nodes may also be assigned user-defined properties, which the user can update after each transition through the use of a callback function. As a component of the Landlab modeling framework, CellLab-CTS models take advantage of a suite of Landlab's tools and capabilities, such as support for standardized input and output.
Institute of Scientific and Technical Information of China (English)
A.Yu. SMOLIN; E.V. SHILKO; S.V. ASTAFUROV; I.S. KONOVALENKO; S.P. BUYAKOVA; S.G. PSAKHIE
2015-01-01
Two classes of composite materials are considered: classical metaleceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is used for modeling the mechanical behaviors of such different heterogeneous materials. The method is based on particle approach and may be considered as a kind of discrete element method. The main feature of the method is the use of many-body forces of inter-element interaction within the formalism of simply deformable element approximation. It was shown that the strength of reinforcing particles and the width of particle-binder interphase boundaries had determining influence on the service characteristics of metaleceramic composite. In particular, the increasing of strength of carbide inclusions may lead to significant increase in the strength and ultimate strain of composite material. On the example of porous zirconia ceramics it was shown that the change in the mechanical properties of pore surface leads to the corresponding change in effective elastic modulus and strength limit of the ceramic sample. The less is the pore size, the more is this effect. The increase in the elastic properties of pore surface of ceramics may reduce its fracture energy.
Parallel 4-Dimensional Cellular Automaton Track Finder for the CBM Experiment
Akishina, Valentina; Kisel, Ivan
2016-10-01
The CBM experiment (FAIR/GSI, Darmstadt, Germany) will focus on the measurement of rare probes at interaction rates up to 10 MHz with data flow of up to 1 TB/s. It requires a novel read-out and data-acquisition concept with self-triggered electronics and free-streaming data. In this case resolving different collisions is not a trivial task and event building must be performed in software online. That requires full online event reconstruction and selection not only in space, but also in time, so-called 4D event building and selection. This is a task of the First-Level Event Selection (FLES). The FLES reconstruction and selection package consists of several modules: track finding, track fitting, short-lived particles finding, event building and event selection. The Cellular Automaton (CA) track finder algorithm was adapted towards time-slice-based reconstruction and included into the CBMROOT framework. In this article, we describe the modification done to the algorithm, as well as the performance of the developed time-based approach.
ONE-DIMENSIONAL CELLULAR AUTOMATON MODEL OF TRAFFIC FLOW BASED ON CAR-FOLLOWING IDEA
Institute of Scientific and Technical Information of China (English)
董力耘; 薛郁; 戴世强
2002-01-01
An improved one-dimensional CA (Cellular Automaton) traffic model was proposed to describe the highway traffic under the periodic boundary conditions. This model was based on the idea of the car-following model, which claims that the motion of a vehicle at one time step depends on both its headway and the synchronous motion of the front vehicle,thus including indirectly the influence of its sub-neighboring vehicle. In addition, the socalled safety distance was introduced to consider the deceleration behavior of vehicles and the stochastic factor was taken into account by introducing the deceleration probability.Meanwhile, the conditional deceleration in the model gives a better description of the phenomena observed on highways. It is found that there exists the metastability and hysteresis effect of traffic flow in the neighborhood of critical density under different initial conditions.Since this model gives a reasonable depiction of the motion of a single vehicle, it is easy to be extended to the case of traffic flow under the control of traffic lights in cities.
Modeling of aluminum-silicon irregular eutectic growth by cellular automaton model
Institute of Scientific and Technical Information of China (English)
Rui Chen; Qing-yan Xu; Bai-cheng Liu
2016-01-01
Due to the extensive application of Al-Si aloys in the automotive and aerospace industries as structural components, an understanding of their microstructural formation, such as dendrite and (Al+Si) eutectic, is of great importance to control the desirable microstructure, so as to modify the performance of castings. Since previous major themes of microstructural simulation are dendrite and regular eutectic growth, few efforts have been paid to simulate the irregular eutectic growth. Therefore, a multiphase celular automaton (CA) model is developed and applied to simulate the time-dependent Al-Si irregular eutectic growth. Prior to model establishment, related experiments were carried out to investigate the inlfuence of cooling rate and Sr modiifcation on the growth of eutectic Si. This CA model incorporates several aspects, including growth algorithms and nucleation criterion, to achieve the competitive and cooperative growth mechanism for nonfaceted-faceted Al-Si irregular eutectic. The growth kinetics considers thermal undercooling, constitutional undercooling, and curvature undercooling, as wel as the anisotropic characteristic of eutectic Si growth. The capturing rule takes into account the effects of modiifcation on the silicon growth behaviors. The simulated results indicate that for unmodiifed aloy, the higher eutectic undercooling results in the higher eutectic growth velocity, and a more reifned eutectic microstructure as wel as narrower eutectic lamelar spacing. For modiifed aloy, the eutectic silicon tends to be obvious ifbrous morphology and the morphology of eutectic Si is determined by both chemical modiifer and cooling rate. The predicted microstructure of Al-7Si aloy under different solidiifcation conditions shows that this proposed model can successfuly reproduce both dendrite and eutectic microstructures.
Hetherington, A. P.; Steacy, S.; McCloskey, J.
2007-12-01
Seismicity spatial and temporal patterns are strongly influenced by stress interaction between faults. However the effects of such interaction on earthquake statistics is not yet well understood. Computer models provide accurate, large and complete datasets to investigate this issue and also have the benefit of allowing direct comparison of seismicity behavior in time and space in networks, with and without fault interaction. We investigate the effect of such interaction on modeled real-world fault networks of varying complexity using a cellular-automata based model. Each 3-D fault within the fault network is modeled by a discrete cellular automaton. The cell size is 1 km square which allows for a minimum earthquake size of approximately Mw=4. The cell strength is distributed fractally across each fault and all cells are loaded by a remote tectonic stressing rate. When the stress on a cell exceeds its strength, the cell fails and stress is transferred to its nearest neighbors which may in turn cause them to break allowing the earthquake to grow. These stress transfer rules allow realistic stress concentrations to develop at the boundary of the rupture. If the extent of the rupture exceeds a user defined minimum length, and if interaction between faults is allowed, a boundary element method is used to calculate stress transfer to neighboring faults. Here we present results from four simulated fault networks based on active faults in the San Francisco Bay Area, California, the Northern Anatolian Fault, Turkey, Southern California, and the Marlborough Fault System, South Island, New Zealand. These are chosen for their varying level of fault complexity and we examine both interacting and non-interacting models in terms of their b-value and recurrence intervals for each region. Results will be compared and discussed.
Directory of Open Access Journals (Sweden)
S. G. Psakhie
2013-04-01
Full Text Available An approach to multiscale description of deformation and fracture of brittle porous materials on the basis of movable cellular automaton method was proposed. The material characterized by pore size distribution function having two maxima was considered. The core of the proposed approach consists in finding the automaton effective response function by means of direct numerical simulation of representative volume of the porous material. A hierarchical two-scale model of mechanical behavior of ceramics under compression and shear loading was developed. Zirconia based ceramics with pore size greater than the average grain size was considered. At the first scale of the model only small pores (corresponding to the first maximum of the pore size distribution function were taking into account explicitly (by removing automata from the initial structure. The representative volume and effective elastic properties of the porous material at this scale were evaluated. At the second scale of the model, big pores were taking into account explicitly, the parameters of the matrix corresponded to the ones determined at the first scale. Simulation results showed that the proposed multiscale model allows qualitatively and quantitatively correct describing of deformation and fracture of brittle material with hierarchical porous structure.
Institute of Scientific and Technical Information of China (English)
张琴; 张友静; 张滔
2012-01-01
This paper presents an improved Case-Based Reasoning based Cellular Automata model (CBR-CA) in modeling multiple land covers changes. Currently, various research communities have tried to build and apply mathematic models with CBR or CA as systemic method to study concerning specific geo-scientific problems. However.original CBR-CA model has problems in modeling numerous class changes,especially in modeling land cover changes with large region and long time. In this paper,an improved CBR-CA is designed to calculate conversion probabilities for computing multiple land cover. Firstly, the macro transition probability of each class is added to the objective function, which can express the characteristic of multiple class changes. Then, considering the time weight, which can reflect the space-time changes of land cover, the final probability function is derived by both. In addition, due to variation of land cover types and their spatial relationships in complex geography changes, Monte Carlo is made use of deciding the final transition classes. This model has been applied to simulate the land cover changes of the source of the Yellow River in 1995,2000 and 2006,and has been applied to predict this region in 2012 and 2018 by building the historical case-based database with the land cover data in 1977 and 1985. The simulated and actual patterns are basic consistent in amounts,accounting for 0.002% ,0.012% and 0.005% of the total error,respectively, the space accuracies totally beyond 70%. The result indicates that this model can simulate and predict the land cover changes which are with multiple classes and with long time.%对基于案例推理的元胞自动机模型(CBR-CA)进行改进,将各类别的宏观转移概率添加到目标函数中,体现各类别的转变特征,并增加时间权重来确定转移概率,实现时间尺度上的模拟；由于土地覆盖变化的多样性和空间结构的复杂性,利用Monte Carlo(M-C)法确定土地覆盖的最终转换
Institute of Scientific and Technical Information of China (English)
Jiang Rui; Jin Wen-Long; Wu Qing-Song
2008-01-01
Recently, a number of efforts are underway to investigate inter-vehicle communications (IVC). This paper studies the instantaneous information propagation behaviours based on IVC in three different traffic situations (free flow,synchronized flow and stop-and-go waves) in a cellular automaton model. It is shown that different behaviours appear in stop-and-go waves from those in free flow and synchronized flow. While the distribution of Multi-hop Communication Distance (MhCD) is either exponential or uniform in free flow and synchronized flow, the distribution of MhCD is either exponential or with a single peak in stop-and-go waves.
Energy Technology Data Exchange (ETDEWEB)
Konovalenko, Igor S., E-mail: igkon@ispms.tsc.ru; Smolin, Alexey Yu., E-mail: igkon@ispms.tsc.ru; Konovalenko, Ivan S., E-mail: igkon@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Promakhov, Vladimir V. [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Psakhie, Sergey G. [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)
2014-11-14
Movable cellular automaton method was used for investigating the mechanical behavior of ceramic composites under uniaxial compression. A 2D numerical model of ceramic composites based on oxides of zirconium and aluminum with different structural parameters was developed using the SEM images of micro-sections of a real composite. The influence of such structural parameters as the geometrical dimensions of layers, inclusions, and their spatial distribution in the sample, the volume content of the composite components and their mechanical properties (as well as the amount of zirconium dioxide that underwent the phase transformation) on the fracture, strength, deformation and dissipative properties was investigated.
COMPLEXITY OF LIMIT LANGUAGE OF THE ELEMENTARY CELLULAR AUTOMATON OF RULE 22%22号初等元胞自动机的极限语言复杂性
Institute of Scientific and Technical Information of China (English)
江志松; 王益
2005-01-01
In this paper,the limit set of the elementary cellular automaton of rule 22 is considered.The limit language is defined from limit set and its complexity is studied by using formal language theory.It is proved that this language is not a regular language.This result shows that the dynamics of this cellular automaton is actually complicated.
Institute of Scientific and Technical Information of China (English)
江欣国; 夏亮
2016-01-01
为研究强制换道及冲突点分布对高速公路临时瓶颈交通流的影响,在NS(NaSch)模型和STCA (symmetric two-lane cellular automata)模型的基础上,引入强制换道规则,根据瓶颈口上游驾驶员心理状态的变化,建立高速公路瓶颈交通流模型.在开口边界条件下,针对不同的安全换道概率、强制换道概率、冲突点距离和冲突区间长度参数,模拟得到瓶颈交通流量和换道频率与车辆到达率的关系.仿真结果表明,安全换道行为对系统流量影响小;强制换道行为是降低瓶颈系统最大流量的主要因素,当安全换道概率为0.5时,强制换道概率从0.0增加至0.1,最大流量下降了17％;冲突点距离的增加缓解了交通拥堵程度,当冲突点距离从1 cell增加至4 cell时,临界车辆到达率上升了4％;冲突区间长度对交通事故风险的影响较大,最大强制换道频率随冲突区间长度的增加而增加.
Properties of a Finite Stochastic Cellular Automaton Toy Model of Earthquakes
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Białecki Mariusz
2015-08-01
Full Text Available Finite version of Random Domino Automaton - a recently proposed toy model of earthquakes - is investigated in detail. Respective set of equations describing stationary state of the FRDA is derived and compared with infinite case. It is shown that for a system of large size, these equations are coincident with RDA equations. We demonstrate a non-existence of exact equations for size N ≥ 5 and propose appropriate approximations, the quality of which is studied in examples obtained within the framework of Markov chains.
22号初等元胞自动机的演化复杂性%EVOLUTION COMPLEXITY OF THE ELEMENTARY CELLULAR AUTOMATON OF RULE 22
Institute of Scientific and Technical Information of China (English)
王益; 江志松
2002-01-01
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.
A refined cellular automaton model to rectify impractical vehicular movement behavior
Lan, Lawrence W.; Chiou, Yu-Chiun; Lin, Zih-Shin; Hsu, Chih-Cheng
2009-09-01
When implementing cellular automata (CA) into a traffic simulation, one common defect yet to be rectified is the abrupt deceleration when vehicles encounter stationary obstacles or traffic jams. To be more in line with real world vehicular movement, this paper proposes a piecewise-linear movement to replace the conventional particle-hopping movement adopted in most previous CA models. Upon this adjustment and coupled with refined cell system, a new CA model is developed using the rationale of Forbes’ et al. car-following concept. The proposed CA model is validated on a two-lane freeway mainline context. It shows that this model can fix the unrealistic deceleration behaviors, and thus can reflect genuine driver behavior in the real world. The model is also capable of revealing Kerner’s three-phase traffic patterns and phase transitions among them. Furthermore, the proposed CA model is applied to simulate a highway work zone wherein traffic efficiency (maximum flow rates) and safety (speed deviations) impacted by various control schemes are tested.
Effect of Driver Scope Awareness in the Lane Changing Maneuvers Using Cellular Automaton Model
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Kohei Arai
2013-07-01
Full Text Available This paper investigated the effect of drivers’ visibility and their perception (e.g., to estimate the speed and arrival time of another vehicle on the lane changing maneuver. The term of scope awareness was used to describe the visibility required by the driver to make a perception about road condition and the speed of vehicle that exist in that road. A computer simulation model was conducted to show this driver awareness behavior. This studying attempt to precisely catching the lane changing behavior and illustrate the scope awareness parameter that reflects driver behavior. This paper proposes a simple cellular automata model for studying driver visibility effects of lane changing maneuver and driver perception of estimated speed. Different values of scope awareness were examined to capture its effect on the traffic flow. Simulation results show the ability of this model to capture the important features of lane changing maneuver and revealed the appearance of the short-thin solid line jam and the wide solid line jam in the traffic flow as the consequences of lane changing maneuver.
Matsubara, Takashi; Torikai, Hiroyuki
2016-04-01
Modeling and implementation approaches for the reproduction of input-output relationships in biological nervous tissues contribute to the development of engineering and clinical applications. However, because of high nonlinearity, the traditional modeling and implementation approaches encounter difficulties in terms of generalization ability (i.e., performance when reproducing an unknown data set) and computational resources (i.e., computation time and circuit elements). To overcome these difficulties, asynchronous cellular automaton-based neuron (ACAN) models, which are described as special kinds of cellular automata that can be implemented as small asynchronous sequential logic circuits have been proposed. This paper presents a novel type of such ACAN and a theoretical analysis of its excitability. This paper also presents a novel network of such neurons, which can mimic input-output relationships of biological and nonlinear ordinary differential equation model neural networks. Numerical analyses confirm that the presented network has a higher generalization ability than other major modeling and implementation approaches. In addition, Field-Programmable Gate Array-implementations confirm that the presented network requires lower computational resources.
Study on PI active queue management based on cellular automaton%基于元胞自动机的PI主动队列管理方法研究
Institute of Scientific and Technical Information of China (English)
俞立峰
2013-01-01
针对传统的PI(Proportional Integral)算法收敛速度慢等问题,基于瞬时到达速率提出了一种新的PI主动队列管理算法PICA(Proportional Integral Based on Cellular Automaton).首先,该算法结合瞬时队长和瞬时到达速率建立了丢包策略,并利用元胞自动机刻画了数据包的动态特性.同时,通过仿真实验,将该算法与传统的PI算法以及RPI (Rate based Proportional and Integral)算法进行比较,结果发现PICA算法在有效传输数据包、时延和丢包率等方面的性能都较优.%In order to mitigate the slow of convergence rate in traditional Proportional Integral algorithm, a novel active queue management algorithm (Proportional Integral Based on Cellular Automaton, PICA) is proposed based on instantaneous arrival rate. At first, combined with instantaneous queue length and instantaneous arrival rate, the dropping strategy is presented in this algorithm, and the dynamic characteristic of packet is depicted by cellular automaton. Then, a simulation was conducted to study on the algorithm performance between PICA and PI, as well as RPKRate based Proportional and Integral). The result shows that it is better performance in efficient transmission packets, delay and dropping rate for PICA algorithm.
Tian, Junfang; Ma, Shoufeng; Zhu, Chenqiang; Jiang, Rui; Ding, YaoXian
2015-01-01
This paper proposes an improved cellular automaton traffic flow model based on the brake light model, which takes into account that the desired time gap of vehicles is remarkably larger than one second. Although the hypothetical steady state of vehicles in the deterministic limit corresponds to a unique relationship between speeds and gaps in the proposed model, the traffic states of vehicles dynamically span a two-dimensional region in the plane of speed versus gap, due to the various randomizations. It is shown that the model is able to well reproduce (i) the free flow, synchronized flow, jam as well as the transitions among the three phases; (ii) the evolution features of disturbances and the spatiotemporal patterns in a car-following platoon; (iii) the empirical time series of traffic speed obtained from NGSIM data. Therefore, we argue that a model can potentially reproduce the empirical and experimental features of traffic flow, provided that the traffic states are able to dynamically span a 2D speed-gap...
Directory of Open Access Journals (Sweden)
A.Yu. Smolin
2015-03-01
Full Text Available Two classes of composite materials are considered: classical metal–ceramic composites with reinforcing hard inclusions as well as hard ceramics matrix with soft gel inclusions. Movable cellular automaton method is used for modeling the mechanical behaviors of such different heterogeneous materials. The method is based on particle approach and may be considered as a kind of discrete element method. The main feature of the method is the use of many-body forces of inter-element interaction within the formalism of simply deformable element approximation. It was shown that the strength of reinforcing particles and the width of particle-binder interphase boundaries had determining influence on the service characteristics of metal–ceramic composite. In particular, the increasing of strength of carbide inclusions may lead to significant increase in the strength and ultimate strain of composite material. On the example of porous zirconia ceramics it was shown that the change in the mechanical properties of pore surface leads to the corresponding change in effective elastic modulus and strength limit of the ceramic sample. The less is the pore size, the more is this effect. The increase in the elastic properties of pore surface of ceramics may reduce its fracture energy.
Tucker, G. E.; Hobley, D. E. J.; Hutton, E.; Gasparini, N. M.; Istanbulluoglu, E.; Adams, J. M.; Nudurupati, S. S.
2015-11-01
CellLab-CTS 2015 is a Python-language software library for creating two-dimensional, continuous-time stochastic (CTS) cellular automaton models. The model domain consists of a set of grid nodes, with each node assigned an integer state-code that represents its condition or composition. Adjacent pairs of nodes may undergo transitions to different states, according to a user-defined average transition rate. A model is created by writing a Python code that defines the possible states, the transitions, and the rates of those transitions. The code instantiates, initializes, and runs one of four object classes that represent different types of CTS model. CellLab-CTS provides the option of using either square or hexagonal grid cells. The software provides the ability to treat particular grid-node states as moving particles, and to track their position over time. Grid nodes may also be assigned user-defined properties, which the user can update after each transition through the use of a callback function. As a component of the Landlab modeling framework, CellLab-CTS models take advantage of a suite of Landlab's tools and capabilities, such as support for standardized input and output.
On the Effect of Quantum Noise in a Quantum-Relativistic Prisoner's Dilemma Cellular Automaton
Alonso-Sanz, Ramón; Situ, Haozhen
2016-12-01
The disrupting effect of quantum noise on the dynamics of a spatial quantum relativistic formulation of the iterated prisoner's dilemma game with variable entangling is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. The game is assessed in fair and unfair contests.
Endo, Noritaka
2016-12-01
A simple stochastic cellular automaton model is proposed for simulating bedload transport, especially for cases with a low transport rate and where available sediments are very sparse on substrates in a subaqueous system. Numerical simulations show that the bed type changes from sheet flow through sand patches to ripples as the amount of sand increases; this is consistent with observations in flume experiments and in the field. Without changes in external conditions, the sand flux calculated for a given amount of sand decreases over time as bedforms develop from a flat bed. This appears to be inconsistent with the general understanding that sand flux remains unchanged under the constant-fluid condition, but it is consistent with the previous experimental data. For areas of low sand abundance, the sand flux versus sand amount (flux-density relation) in the simulation shows a single peak with an abrupt decrease, followed by a long tail; this is very similar to the flux-density relation seen in automobile traffic flow. This pattern (the relation between segments of the curve and the corresponding bed states) suggests that sand sheets, sand patches, and sand ripples correspond respectively to the free-flow phase, congested phase, and jam phase of traffic flows. This implies that sand topographic features on starved beds are determined by the degree of interference between sand particles. Although the present study deals with simple cases only, this can provide a simplified but effective modeling of the more complicated sediment transport processes controlled by interference due to contact between grains, such as the pulsatory migration of grain-size bimodal mixtures with repetition of clustering and scattering.
A hybrid cellular automaton model of solid tumor growth and bioreductive drug transport.
Kazmi, Nabila; Hossain, M A; Phillips, Roger M
2012-01-01
Bioreductive drugs are a class of hypoxia selective drugs that are designed to eradicate the hypoxic fraction of solid tumors. Their activity depends upon a number of biological and pharmacological factors and we used a mathematical modeling approach to explore the dynamics of tumor growth, infusion, and penetration of the bioreductive drug Tirapazamine (TPZ). An in-silico model is implemented to calculate the tumor mass considering oxygen and glucose as key microenvironmental parameters. The next stage of the model integrated extra cellular matrix (ECM), cell-cell adhesion, and cell movement parameters as growth constraints. The tumor microenvironments strongly influenced tumor morphology and growth rates. Once the growth model was established, a hybrid model was developed to study drug dynamics inside the hypoxic regions of tumors. The model used 10, 50 and 100 \\mu {\\rm M} as TPZ initial concentrations and determined TPZ pharmacokinetic (PK) (transport) and pharmacodynamics (cytotoxicity) properties inside hypoxic regions of solid tumor. The model results showed that diminished drug transport is a reason for TPZ failure and recommend the optimization of the drug transport properties in the emerging TPZ generations. The modeling approach used in this study is novel and can be a step to explore the behavioral dynamics of TPZ.
Accelerating a three-dimensional eco-hydrological cellular automaton on GPGPU with OpenCL
Senatore, Alfonso; D'Ambrosio, Donato; De Rango, Alessio; Rongo, Rocco; Spataro, William; Straface, Salvatore; Mendicino, Giuseppe
2016-10-01
This work presents an effective implementation of a numerical model for complete eco-hydrological Cellular Automata modeling on Graphical Processing Units (GPU) with OpenCL (Open Computing Language) for heterogeneous computation (i.e., on CPUs and/or GPUs). Different types of parallel implementations were carried out (e.g., use of fast local memory, loop unrolling, etc), showing increasing performance improvements in terms of speedup, adopting also some original optimizations strategies. Moreover, numerical analysis of results (i.e., comparison of CPU and GPU outcomes in terms of rounding errors) have proven to be satisfactory. Experiments were carried out on a workstation with two CPUs (Intel Xeon E5440 at 2.83GHz), one GPU AMD R9 280X and one GPU nVIDIA Tesla K20c. Results have been extremely positive, but further testing should be performed to assess the functionality of the adopted strategies on other complete models and their ability to fruitfully exploit parallel systems resources.
Institute of Scientific and Technical Information of China (English)
王益; Morita Kenichi
2006-01-01
Symbolic dynamics of cellular automata is introduced by coarse-graining the temporal evolution orbits. Evolution languages are defined. By using the theory of formal languages and automata, the complexity of evolution languages of the elementary cellular automaton of rule 146 is studied and it is proved 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. Also, the same results hold for the equivalent (under conjugation) elementary cellular automaton of rule 182.
Optimization of the Design of Pre-Signal System Using Improved Cellular Automaton
Directory of Open Access Journals (Sweden)
Yan Li
2014-01-01
Full Text Available The pre-signal system can improve the efficiency of intersection approach under rational design. One of the main obstacles in optimizing the design of pre-signal system is that driving behaviors in the sorting area cannot be well evaluated. The NaSch model was modified by considering slow probability, turning-deceleration rules, and lane changing rules. It was calibrated with field observed data to explore the interactions among design parameters. The simulation results of the proposed model indicate that the length of sorting area, traffic demand, signal timing, and lane allocation are the most important influence factors. The recommendations of these design parameters are demonstrated. The findings of this paper can be foundations for the design of pre-signal system and show promising improvement in traffic mobility.
Optimization of the design of pre-signal system using improved cellular automaton.
Li, Yan; Li, Ke; Tao, Siran; Wan, Xia; Chen, Kuanmin
2014-01-01
The pre-signal system can improve the efficiency of intersection approach under rational design. One of the main obstacles in optimizing the design of pre-signal system is that driving behaviors in the sorting area cannot be well evaluated. The NaSch model was modified by considering slow probability, turning-deceleration rules, and lane changing rules. It was calibrated with field observed data to explore the interactions among design parameters. The simulation results of the proposed model indicate that the length of sorting area, traffic demand, signal timing, and lane allocation are the most important influence factors. The recommendations of these design parameters are demonstrated. The findings of this paper can be foundations for the design of pre-signal system and show promising improvement in traffic mobility.
Directory of Open Access Journals (Sweden)
Matthew W Johnston
Full Text Available The Indo-pacific panther grouper (Chromileptes altiveli is a predatory fish species and popular imported aquarium fish in the United States which has been recently documented residing in western Atlantic waters. To date, the most successful marine invasive species in the Atlantic is the lionfish (Pterois volitans/miles, which, as for the panther grouper, is assumed to have been introduced to the wild through aquarium releases. However, unlike lionfish, the panther grouper is not yet thought to have an established breeding population in the Atlantic. Using a proven modeling technique developed to track the lionfish invasion, presented is the first known estimation of the potential spread of panther grouper in the Atlantic. The employed cellular automaton-based computer model examines the life history of the subject species including fecundity, mortality, and reproductive potential and combines this with habitat preferences and physical oceanic parameters to forecast the distribution and periodicity of spread of this potential new invasive species. Simulations were examined for origination points within one degree of capture locations of panther grouper from the United States Geological Survey Nonindigenous Aquatic Species Database to eliminate introduction location bias, and two detailed case studies were scrutinized. The model indicates three primary locations where settlement is likely given the inputs and limits of the model; Jupiter Florida/Vero Beach, the Cape Hatteras Tropical Limit/Myrtle Beach South Carolina, and Florida Keys/Ten Thousand Islands locations. Of these locations, Jupiter Florida/Vero Beach has the highest settlement rate in the model and is indicated as the area in which the panther grouper is most likely to become established. This insight is valuable if attempts are to be made to halt this potential marine invasive species.
Berkovich, Simon
2015-04-01
The undamental advantage of a Cellular automaton construction foris that it can be viewed as an undetectable absolute frame o reference, in accordance with Lorentz-Poincare's interpretation.. The cellular automaton model for physical poblems comes upon two basic hurdles: (1) How to find the Elemental Rule that, and how to get non-locality from local transformations. Both problems are resolved considering the transfomation rule of mutual distributed synchronization Actually any information proessing device starts with a clocking system. and it turns out that ``All physical phenomena are different aspects of the high-level description of distributed mutual synchronization in a network of digital clocks''. Non-locality comes from two hugely different time-scales of signaling.. The universe is acombinines information and matter processes, These fast spreading diffusion wave solutions create the mechanism of the Holographic Universe. And thirdly Disengaged from synchronization, circular counters can perform memory functions by retaining phases of their oscillations, an idea of Von Neumann'. Thus, the suggested model generates the necessary constructs for the physical world as an Internet of Things. Life emerges due to the specifics of macromolecules that serve as communication means, with the holographic memory...
Institute of Scientific and Technical Information of China (English)
WANG Kuang-fei; LI Bang-sheng; MI Guo-fa; GUO Jing-jie; FU Heng-zhi
2008-01-01
Solute diffusion controlled solidification model was used to simulate the initial stage cellular to dendrite transition of Ti44AI alloys during directional solidification at different velocities. The simulation results show that during this process, a mixed structure composed of cells and dendrites was observed, where secondary dendrites are absent at facing surface with parallel closely spaced dendrites, which agrees with the previous experimental observa-tion. The dendrite spacings are larger than cellular spacings at a given rate, and the columnar grain spacing sharply increases to a maximum as solidification advance to coexistence zone. In addition, simulation also revealed that decreasing the numbers of the seed causes the trend of unstable dendrite transition to increase. Finally, the main influence factors affecting cell/dendrite transition were analyzed, which could be the change of growth rates resulting in slight fluctuations of liquid composition occurred at growth front. The simulation results are in reasonable agreement with the results of previous theoretical models and experimental observation at low cooling rates.
基于元胞自动机理论的协同设计任务调度模型%Collaboration Design Tasks Scheduling Model Based on Cellular Automaton
Institute of Scientific and Technical Information of China (English)
徐鸿翔; 吴晶华; 张向华
2011-01-01
分析了设计任务调度的特点,提出了基于元胞自动机理论的调度模型。对元胞自动机任务调度模型进行了数学描述,对设计任务调度的策略进行了分析,建立了元胞自动机目标调度模型,通过具体算例对所提出的模型进行了验证,表明元胞自动机模型可以有效地进行任务调度的优化。%The characteristic of design tasks scheduling was analyzed,and a collaborative tasks scheduling model based on Cellular Automaton（CA） was put forward.Firstly,mathematics description was done for design tasks scheduling model based on Cellular Automaton.Secondly,the strategy for design tasks scheduling was analyzed.And so,the scheduling target model was established.Finally,a simulation experiment was carried out by using the proposed algorithm.The convergent velocity would be fast and the ability to optimize would be better.
Al-Husari, Maymona; Murdoch, Craig; Webb, Steven D
2014-10-01
Some tumours are known to exhibit an extracellular pH that is more acidic than the intracellular, creating a 'reversed pH gradient' across the cell membrane and this has been shown to affect their invasive and metastatic potential. Tumour hypoxia also plays an important role in tumour development and has been directly linked to both tumour morphology and aggressiveness. In this paper, we present a hybrid mathematical model of intracellular pH regulation that examines the effect of oxygen and pH on tumour growth and morphology. In particular, we investigate the impact of pH regulatory mechanisms on the cellular pH gradient and tumour morphology. Analysis of the model shows that: low activity of the Na+/H+ exchanger or a high rate of anaerobic glycolysis can give rise to a "fingering" tumour morphology; and a high activity of the lactate/H+ symporter can result in a reversed transmembrane pH gradient across a large portion of the tumour mass. Also, the reversed pH gradient is spatially heterogeneous within the tumour, with a normal pH gradient observed within an intermediate growth layer within the spheroid. We also include a fractal dimension analysis of the simulated tumour contours, in which we compare the fractal dimensions of the simulated tumour surfaces with those found experimentally via photomicrographs.
A two-lane cellular automaton traffic flow model with the influence of driver, vehicle and road
Zhao, Han-Tao; Nie, Cen; Li, Jing-Ru; Wei, Yu-Ao
2016-07-01
On the basis of one-lane comfortable driving model, this paper established a two-lane traffic cellular automata model, which improves the slow randomization effected by brake light. Considering the driver psychological characteristics and mixed traffic, we studied the lateral influence between vehicles on adjacent lanes. Through computer simulation, the space-time diagram and the fundamental figure under different conditions are obtained. The study found that aggressive driver makes a slight congestion in low-density traffic and improves the capacity of high-density traffic, when the density exceeds 20pcu/km the more aggressive drivers the greater the flow, when the density below 40pcu/km driver character makes an effect, the more cautious driver, the lower the flow. The ratio of big cars has the same effect as the ratio of aggressive drivers. Brake lights have the greatest impact on traffic flow and when the density exceeds 10pcu/km the traffic flow fluctuates. Under periodic boundary conditions, the disturbance of road length on traffic is minimal. The lateral influence only play a limited role in the medium-density conditions, and only affect the average speed of traffic at low density.
Simulation of primary static recrystallization with cellular operator model
Mukhopadhyay, Prantik
2005-01-01
1. Based on the modified cellular automata approach of Reher [60] a cellular operator model has been developed that is capable of accounting for spatial and temporal inhomogeneity on a finer scale. For this a scalable subgrid automaton is introduced that allows for a high spatial resolution on demand and still high computational efficiency. The scalable subgrid permits to track the minute changes of growth front during recrystallization owing to local variations of boundary mobility and net d...
Institute of Scientific and Technical Information of China (English)
李庆定; 董力耘; 戴世强
2009-01-01
利用双车道元胞自动机模型,研究公交车停靠对道路混合交通流的影响.针对港湾式和非港湾式两种不同公交车站设置,在开放边界下模拟了公交车停靠所产生的交通瓶颈问题,给出了车辆入流概率.公交车比例相平面上的相图,区分了自由流相和拥挤相,研究了相图各区中公交车站附近的平均密度和速度分布图,比较了两种公交车站情况下的道路交通流的动力学特征.研究发现,当公交车比例较小时,与非港湾式车站相比,港湾式车站可以显著改善车站处的交通状况.%In this paper, the influence of typical bus stops on traffic flow is investigated with the cellular automaton traffic model. For on-line and off-line bus stops, a two-lane cellular automaton model is proposed to simulate the traffic bottleneck induced by bus stopping under the open boundary condition. The phase diagram in the phase plane of injection probability and bus fraction is provided and two phases, i.e., the free flow phase and congested flow phase, are distinguished. The distributions of the mean density and velocity near the bus stop in different traffic phases are given and the comparison of dynamical characteristics of traffic flows is made for different types of bus stops. It is found that using the off-line bus stop can significandy improve the traffic flow in its neighboring region, compared with the on-line bus stop in the case of small fraction of buses.
Free fall and cellular automata
Directory of Open Access Journals (Sweden)
Pablo Arrighi
2016-03-01
Full Text Available Three reasonable hypotheses lead to the thesis that physical phenomena can be described and simulated with cellular automata. In this work, we attempt to describe the motion of a particle upon which a constant force is applied, with a cellular automaton, in Newtonian physics, in Special Relativity, and in General Relativity. The results are very different for these three theories.
Mente, Carsten; Prade, Ina; Brusch, Lutz; Breier, Georg; Deutsch, Andreas
2011-07-01
Lattice-gas cellular automata (LGCAs) can serve as stochastic mathematical models for collective behavior (e.g. pattern formation) emerging in populations of interacting cells. In this paper, a two-phase optimization algorithm for global parameter estimation in LGCA models is presented. In the first phase, local minima are identified through gradient-based optimization. Algorithmic differentiation is adopted to calculate the necessary gradient information. In the second phase, for global optimization of the parameter set, a multi-level single-linkage method is used. As an example, the parameter estimation algorithm is applied to a LGCA model for early in vitro angiogenic pattern formation.
Institute of Scientific and Technical Information of China (English)
周彬镔; 陈雪波
2015-01-01
Social network has a characteristic of small world , with high cluster coefficient and short average distance .In order to do some research on epidemic spread in small world network and points ’ voluntary suppressions under a global warning , a model based on CA ( cellular automaton ) is proposed .Combining with normal cloud model , we give the model some adaptive properties . Points in the model can break links and connect to others .Under a global warning , we let points abide by danger awareness func-tion.Using AHP model, they are inclined to avoid danger points .Simulation results show that this model is good at simulating epidemic spread and it gives us an explanation of why global warning can postpone the epidemic spread on a network .%人际网络具有小世界特征，拥有高聚类系数、短平均路径等特点。为研究病毒在小世界网络中的传播动力学及全局预警下节点的自主抑制行为，本文基于元胞自动机理论，提出一种小世界网络上的元胞自动机病毒传播模型。结合云模型，模型中节点在病毒传播过程中拥有断开与重连的自适应性，拥有节点危害性认识能力，可参照全局预警，运用层次分析法，对高危节点主动避让。仿真结果表明，该模型可较好模拟病毒的实际传播，通过全局预警可促使节点对高危节点进行规避，以延缓病毒传播。
Institute of Scientific and Technical Information of China (English)
张柠溪; 祝会兵; 林亨; 黄梦圆
2015-01-01
基于NaSch元胞自动机交通流模型，考虑司机复杂的性格特征和驾驶行为差异，引入相邻车辆的动态车间距，提出了一个改进的单车道元胞自动机交通流模型。通过数值模拟得到了流量-密度关系，在中高密度区域呈现出一种弥散分布的状态而非惟一确定的关系，再现了交通系统中的自由流、同步流及宽幅运动阻塞，表明道路上即使没有交通瓶颈也会出现同步流和拥挤交通，同时揭示了在同步流中存在的车辆高速跟驰现象，高速跟驰率与交通实测结果较为符合。%Based on the NaSch cellular automaton traffic model, a modified single lane traffic model is proposed by considering the dynamic headway of successive vehicles, in which the complex characteristic and driving behavior difference between drivers are taken into account. The relationship between the flow rate and the traffic density is obtained by the numerical simulation, and it shows a two-dimensional region in the flow density plane. The three traffic phases, i.e., free flow, synchronized flow, and wide moving jams, are exhibited. It indicates that the synchronized flow and traffic jams can appear even if there is no traffic bottleneck. Besides, the high speed car-following phenomenon is indicated when the traffic is in the synchronized flow. The rate of the high speed car-following is in good agreement with the measured result.
An Urban Cellular Automata Model for Simulating Dynamic States on a Local Scale
Directory of Open Access Journals (Sweden)
Jenni Partanen
2016-12-01
Full Text Available In complex systems, flexibility and adaptability to changes are crucial to the systems’ dynamic stability and evolution. Such resilience requires that the system is able to respond to disturbances by self-organizing, which implies a certain level of entropy within the system. Dynamic states (static, cyclical/periodic, complex, and chaotic reflect this generative capacity, and correlate with the level of entropy. For planning complex cities, we need to develop methods to guide such autonomous progress in an optimal manner. A classical apparatus, cellular automaton (CA, provides such a tool. Applications of CA help us to study temporal dynamics in self-organizing urban systems. By exploring the dynamic states of the model’s dynamics resulting from different border conditions it is possible to discover favorable set(s of rules conductive to the self-organizing dynamics and enable the system’s recovery at the time of crises. Level of entropy is a relevant measurement for evaluation of these dynamic states. The 2-D urban cellular automaton model studied here is based on the microeconomic principle that similar urban activities are attracted to each other, especially in certain self-organizing areas, and that the local dynamics of these enclaves affect the dynamics of the urban region by channeling flows of information, goods and people. The results of the modeling experiment indicate that the border conditions have a major impact on the model’s dynamics generating various dynamic states of the system. Most importantly, it seemed that the model could simulate a favorable, complex dynamic state with medium entropy level which may refer to the continuous self-organization of the system. The model provides a tool for exploring and understanding the effects of boundary conditions in the planning process as various scenarios are tested: resulting dynamics of the system can be explored with such “planning rules” prior to decisions, helping to
Finite Random Domino Automaton
Bialecki, Mariusz
2012-01-01
Finite version of Random Domino Automaton (FRDA) - recently proposed a toy model of earthquakes - is investigated. Respective set of equations describing stationary state of the FRDA is derived and compared with infinite case. It is shown that for the system of big size, these equations are coincident with RDA equations. We demonstrate a non-existence of exact equations for size N bigger then 4 and propose appropriate approximations, the quality of which is studied in examples obtained within Markov chains framework. We derive several exact formulas describing properties of the automaton, including time aspects. In particular, a way to achieve a quasi-periodic like behaviour of RDA is presented. Thus, based on the same microscopic rule - which produces exponential and inverse-power like distributions - we extend applicability of the model to quasi-periodic phenomena.
人非共板条件下的混合交通流元胞自动机模型%Mixed Traffic Flow Cellular Automaton Model Based on Shared-Use Sidewalk
Institute of Scientific and Technical Information of China (English)
邓建华
2011-01-01
提出建立多尺度、多邻域规则元胞自动机模型来描述城市道路两侧人行道人非共板条件下的行人与自行车混行交通流.人非共板是一种新颖的慢行交通管理模式,但进行这种人行道规划、设计时,指标选取往往会缺少理论支持,运营时缺乏定量评价运行状态的手段.本文以城市道路单侧人行道板上同向行人和自行车共板的情况为研究对象,考虑自行车与行人几何尺寸、元胞状态值及邻域定义等方面的差异,建立了统一的混合元胞自动机模型.该模型能较好地描述这两种交通方式相互干扰现象,通过模型演化能方便地获取阻挡概率等交通运行状态评价参数,为人非共板的规划和设计提供可靠的理论依据.%Study on the pedestrian-bicycle mixed traffic on the shared-use sidewalks beside to the street,with developing a multi-scale and multi-neighborhood-rule cellular automaton model. The shared-use sidewalk is a novel mode of non-motorized traffic management, but there is lack of theoretical support to select the plan and design parameters, lack of a quantitative method to evaluate the traffic flow state of shared-use sidewalks. The study's object is the synclastic mixed pedestrian and bicycle traffic on a single shared-use sidewalk of urban street. A unified mixed traffic flow cellular automaton model is established based on the difference of the geometric dimensions, status value and neighborhood definition of bicycle-cell and pedestrian-cell. This model describes nicely the interference of bike and pedestrian. It is convenient to obtain evaluation parameters of traffic flow status like as hindrance probability, to provide a reliable theoretical basis as planning and designing the shared-use sidewalk.
Directory of Open Access Journals (Sweden)
Chen Shijia
2013-11-01
Full Text Available Dans le domaine du soudage, les propriétés finales du cordon sont fortement liées à la structure de grains développée au cours des procédés de fusion / resolidification. La maîtrise des propriétés de l'assemblage final passe ainsi par une amélioration de la connaissance de sa structure de ce domaine. Dans cet objectif, un modèle couplé Automates Cellulaires – Eléments Finis est proposé pour simuler le développement, en volume, de cette structure, dans le cadre du soudage TIG. Ce modèle est appliqué au soudage d'acier Duplex 2202 et l'évolution de la structure de grains selon les paramètres procédés est discutée. In the welding area, the final properties of the weld bead are mainly induced by the grain structure developed during the melting and solidification steps. The mastery of the properties of the joining will be achieved with a better knowledge of the developed grain structure. A 3D coupled Cellular Automaton – Finite Element model is proposed in order to simulate the grains development in TIG process. This model is applied to the welding of a duplex stainless steel grade. The grain structure evolution is discussed for the various process parameters.
Malarz, Krzysztof; Kułakowski, Krzysztof
2014-01-01
The problem `human and work' in a model working group is investigated by means of cellular automata technique. Attitude of members of a group towards work is measured by indicator of loyalty to the group (the number of underloaded agents who carry out their tasks), and lack of loyalty (the number of overloaded agents, who give their tasks to other agents). Initially, all agents realize scheduled tasks one-by-one. Agents with the number of scheduled tasks larger than a given threshold change their strategy to `overloaded' one and start avoiding completing tasks by passing them to their colleagues. Optionally, in some conditions, we allow agents to return to `underloaded' state; hence the rule is hysteretic. Results are presented on an influence of i) the density of tasks, ii) the threshold number of tasks assigned to the agents' forcing him/her for strategy change on the system efficiency. We show that a `black' scenario of the system stacking in a jammed phase (with all agents being in overloaded state and ha...
Motzkin numbers out of Random Domino Automaton
Białecki, Mariusz
2011-01-01
Motzkin numbers are derived from a special case of Random Domino Automaton - recently proposed toy model of earthquakes. An exact solution of the set of equations describing stationary state of Random Domino Automaton in "inverse-power" case is presented. A link with Motzkin numbers allows to present explicit form of asymptotic behaviour of the automaton.
Quantum cellular automaton theory of light
Bisio, Alessandro; D'Ariano, Giacomo Mauro; Perinotti, Paolo
2016-05-01
We present a quantum theory of light based on the recent derivation of Weyl and Dirac quantum fields from general principles ruling the interactions of a countable set of abstract quantum systems, without using space-time and mechanics (D'Ariano and Perinotti, 2014). In a Planckian interpretation of the discreteness, the usual quantum field theory corresponds to the so-called relativistic regime of small wave-vectors. Within the present framework the photon is a composite particle made of an entangled pair of free Weyl Fermions, and the usual Bosonic statistics is recovered in the low photon density limit, whereas the Maxwell equations describe the relativistic regime. We derive the main phenomenological features of the theory in the ultra-relativistic regime, consisting in a dispersive propagation in vacuum, and in the occurrence of a small longitudinal polarization, along with a saturation effect originated by the Fermionic nature of the photon. We then discuss whether all these effects can be experimentally tested, and observe that only the dispersive effects are accessible to the current technology via observations of gamma-ray bursts.
Quantum cellular automaton theory of light
Energy Technology Data Exchange (ETDEWEB)
Bisio, Alessandro, E-mail: alessandro.bisio@unipv.it; D’Ariano, Giacomo Mauro; Perinotti, Paolo
2016-05-15
We present a quantum theory of light based on the recent derivation of Weyl and Dirac quantum fields from general principles ruling the interactions of a countable set of abstract quantum systems, without using space–time and mechanics (D’Ariano and Perinotti, 2014). In a Planckian interpretation of the discreteness, the usual quantum field theory corresponds to the so-called relativistic regime of small wave-vectors. Within the present framework the photon is a composite particle made of an entangled pair of free Weyl Fermions, and the usual Bosonic statistics is recovered in the low photon density limit, whereas the Maxwell equations describe the relativistic regime. We derive the main phenomenological features of the theory in the ultra-relativistic regime, consisting in a dispersive propagation in vacuum, and in the occurrence of a small longitudinal polarization, along with a saturation effect originated by the Fermionic nature of the photon. We then discuss whether all these effects can be experimentally tested, and observe that only the dispersive effects are accessible to the current technology via observations of gamma-ray bursts.
The cellular automaton interpretation of quantum mechanics
't Hooft, Gerard
2016-01-01
This book presents the deterministic view of quantum mechanics developed by Nobel Laureate Gerard 't Hooft. Dissatisfied with the uncomfortable gaps in the way conventional quantum mechanics meshes with the classical world, 't Hooft has revived the old hidden variable ideas, but now in a much more systematic way than usual. In this, quantum mechanics is viewed as a tool rather than a theory. The book presents examples of models that are classical in essence, but can be analysed by the use of quantum techniques, and argues that even the Standard Model, together with gravitational interactions, might be viewed as a quantum mechanical approach to analysing a system that could be classical at its core. He shows how this approach, even though it is based on hidden variables, can be plausibly reconciled with Bell's theorem, and how the usual objections voiced against the idea of ‘superdeterminism' can be overcome, at least in principle. This framework elegantly explains - and automatically cures - the problems of...
Simulating Complex Systems by Cellular Automata
Kroc, Jiri; Hoekstra, Alfons G
2010-01-01
Deeply rooted in fundamental research in Mathematics and Computer Science, Cellular Automata (CA) are recognized as an intuitive modeling paradigm for Complex Systems. Already very basic CA, with extremely simple micro dynamics such as the Game of Life, show an almost endless display of complex emergent behavior. Conversely, CA can also be designed to produce a desired emergent behavior, using either theoretical methodologies or evolutionary techniques. Meanwhile, beyond the original realm of applications - Physics, Computer Science, and Mathematics – CA have also become work horses in very different disciplines such as epidemiology, immunology, sociology, and finance. In this context of fast and impressive progress, spurred further by the enormous attraction these topics have on students, this book emerges as a welcome overview of the field for its practitioners, as well as a good starting point for detailed study on the graduate and post-graduate level. The book contains three parts, two major parts on th...
Simulation of earthquakes with cellular automata
Directory of Open Access Journals (Sweden)
P. G. Akishin
1998-01-01
Full Text Available The relation between cellular automata (CA models of earthquakes and the Burridge–Knopoff (BK model is studied. It is shown that the CA proposed by P. Bak and C. Tang,although they have rather realistic power spectra, do not correspond to the BK model. We present a modification of the CA which establishes the correspondence with the BK model.An analytical method of studying the evolution of the BK-like CA is proposed. By this method a functional quadratic in stress release, which can be regarded as an analog of the event energy, is constructed. The distribution of seismic events with respect to this “energy” shows rather realistic behavior, even in two dimensions. Special attention is paid to two-dimensional automata; the physical restrictions on compression and shear stiffnesses are imposed.
Probing Cellular Dynamics with Mesoscopic Simulations
DEFF Research Database (Denmark)
Shillcock, Julian C.
2010-01-01
. But these models struggle to represent processes that are localized in space and time or involve the transport of material through a crowded environment. A novel class of mesoscopic simulation techniques are now able to span length and time scales from nanometers to microns for hundreds of microseconds, and may......-based simulation techniques cannot capture such a broad range. Consequently, at long length scales, models have often been of the Mass Action variety, in which molecular constituents are represented by density fields that vary continuously in space and time, rather than involving discrete molecules...
Recursive definition of global cellular-automata mappings
DEFF Research Database (Denmark)
Feldberg, Rasmus; Knudsen, Carsten; Rasmussen, Steen
1994-01-01
A method for a recursive definition of global cellular-automata mappings is presented. The method is based on a graphical representation of global cellular-automata mappings. For a given cellular-automaton rule the recursive algorithm defines the change of the global cellular-automaton mapping as...
Process Expression of Security Automaton
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Security is an essential aspect for mobile systems. Usually, mobile system modeling and its security policies specification are realized in different techniques. So when constructed a mobile system using formal methods it is difficult to verify if the system comply with any given security policies. A method was introduced to express security automata which specifying enforceable security policies as processes in an extended π-calculus. In this extended π-calculus, an exception termination process was introduced, called bad. Any input which violating a security automaton will correspond to a step of transformation of the process that specifying the security automaton to exception termination process. Our method shows that any security automata which specifying enforceable security policies would decide a process in the extended π-calculus.
Chen, Jingxu; Li, Zhibin; Jiang, Hang; Zhu, Senlai; Wang, Wei
2017-02-01
In recent years, many bicycle lanes on urban streets are replaced with vehicle parking places. Spaces for bicycle riding are reduced, resulting in changes in bicycle and vehicle operational features. The objective of this study is to estimate the impacts of on-street parking on heterogeneous traffic operation on urban streets. A cellular automaton (CA) model is developed and calibrated to simulate bicycle lane-changing on streets with on-street parking. Two types of street segments with different bicycle lane width are considered. From the simulation, two types of conflicts between bicycles and vehicles are identified which are frictional conflicts and blocking conflicts. Factors affecting the frequency of conflicts are also identified. Based on the results, vehicle delay is estimated for various traffic situations considering the range of occupancy levels for on-street parking. Later, a numerical network example is analyzed to estimate the network impact of on-street parking on traffic assignment and operation. Findings of the study are helpful to policies and design regarding on-street vehicle parking to improve the efficiency of traffic operations.
McCune, Matthew; Kosztin, Ioan
2013-03-01
Cellular Particle Dynamics (CPD) is a theoretical-computational-experimental framework for describing and predicting the time evolution of biomechanical relaxation processes of multi-cellular systems, such as fusion, sorting and compression. In CPD, cells are modeled as an ensemble of cellular particles (CPs) that interact via short range contact interactions, characterized by an attractive (adhesive interaction) and a repulsive (excluded volume interaction) component. The time evolution of the spatial conformation of the multicellular system is determined by following the trajectories of all CPs through numerical integration of their equations of motion. Here we present CPD simulation results for the fusion of both spherical and cylindrical multi-cellular aggregates. First, we calibrate the relevant CPD model parameters for a given cell type by comparing the CPD simulation results for the fusion of two spherical aggregates to the corresponding experimental results. Next, CPD simulations are used to predict the time evolution of the fusion of cylindrical aggregates. The latter is relevant for the formation of tubular multi-cellular structures (i.e., primitive blood vessels) created by the novel bioprinting technology. Work supported by NSF [PHY-0957914]. Computer time provided by the University of Missouri Bioinformatics Consortium.
Some Properties of topological pressure on cellular automata
Directory of Open Access Journals (Sweden)
Chih-Hung Chang
2014-09-01
Full Text Available This paper investigates the ergodicity and the power rule of the topological pressure of a cellular automaton. If a cellular automaton is either leftmost or rightmost premutive (due to the terminology given by Hedlund [Math.~Syst.~Theor.~3, 320-375, 1969], then it is ergodic with respect to the uniform Bernoulli measure. More than that, the relation of topological pressure between the original cellular automaton and its power rule is expressed in a closed form. As an application, the topological pressure of a linear cellular automaton can be computed explicitly.
Simulation of Power Control and Diversity of Cellular CDMA
Institute of Scientific and Technical Information of China (English)
RomanPichna; QiangWang; 等
1995-01-01
This paper presents a software package developed by the authors for the simulation of a cellular code division multiple access(CDMA)system.In the simulated system,a number of fac-tors are taken into account including time-correlated fading and shadowing,delays in power control and diversity ,errors in power control commands,soft hand-off,base station diversity,and pilots and diversity transmissions,contributions to the interference.
Mosquito population dynamics from cellular automata-based simulation
Syafarina, Inna; Sadikin, Rifki; Nuraini, Nuning
2016-02-01
In this paper we present an innovative model for simulating mosquito-vector population dynamics. The simulation consist of two stages: demography and dispersal dynamics. For demography simulation, we follow the existing model for modeling a mosquito life cycles. Moreover, we use cellular automata-based model for simulating dispersal of the vector. In simulation, each individual vector is able to move to other grid based on a random walk. Our model is also capable to represent immunity factor for each grid. We simulate the model to evaluate its correctness. Based on the simulations, we can conclude that our model is correct. However, our model need to be improved to find a realistic parameters to match real data.
Microbial Growth Modeling and Simulation Based on Cellular Automata
Directory of Open Access Journals (Sweden)
Hong Men
2013-07-01
Full Text Available In order to simulate the micro-evolutionary process of the microbial growth, [Methods] in this study, we adopt two-dimensional cellular automata as its growth space. Based on evolutionary mechanism of microbial and cell-cell interactions, we adopt Moore neighborhood and make the transition rules. Finally, we construct the microbial growth model. [Results] It can describe the relationships among the cell growth, division and death. And also can effectively reflect spatial inhibition effect and substrate limitation effect. [Conclusions] The simulation results show that CA model is not only consistent with the classic microbial kinetic model, but also be able to simulate the microbial growth and evolution.
Reversible quantum cellular automata
Schumacher, B
2004-01-01
We define quantum cellular automata as infinite quantum lattice systems with discrete time dynamics, such that the time step commutes with lattice translations and has strictly finite propagation speed. In contrast to earlier definitions this allows us to give an explicit characterization of all local rules generating such automata. The same local rules also generate the global time step for automata with periodic boundary conditions. Our main structure theorem asserts that any quantum cellular automaton is structurally reversible, i.e., that it can be obtained by applying two blockwise unitary operations in a generalized Margolus partitioning scheme. This implies that, in contrast to the classical case, the inverse of a nearest neighbor quantum cellular automaton is again a nearest neighbor automaton. We present several construction methods for quantum cellular automata, based on unitaries commuting with their translates, on the quantization of (arbitrary) reversible classical cellular automata, on quantum c...
DEFF Research Database (Denmark)
Weyland, Mathias; Fellermann, Harold; Hadorn, Maik
2013-01-01
In this paper, we propose the MATCHIT Automaton (MA), a theoretical framework that shows how to improve the yield of the synthesis of chemical polymer reactions. This is achieved by separating sub-steps of the path of syn- thesis into compartments. We use chemical containers (chemtainers) to carr...... reticulum and the Golgi apparatus, and we show how this compartmentalization can be exploited for the synthesis of branched polymers. Lastly, we show exam- ples of artificial branched polymers and discuss how the MA can be configured to synthesize them with maximal yield....
Multiscale mathematical modeling and simulation of cellular dynamical process.
Nakaoka, Shinji
2014-01-01
Epidermal homeostasis is maintained by dynamic interactions among molecules and cells at different spatiotemporal scales. Mathematical modeling and simulation is expected to provide clear understanding and precise description of multiscaleness in tissue homeostasis under systems perspective. We introduce a stochastic process-based description of multiscale dynamics. Agent-based modeling as a framework of multiscale modeling to achieve consistent integration of definitive subsystems is proposed. A newly developed algorithm that particularly aims to perform stochastic simulations of cellular dynamical process is introduced. Finally we review applications of multiscale modeling and quantitative study to important aspects of epidermal and epithelial homeostasis.
Simulation of root forms using cellular automata model
Energy Technology Data Exchange (ETDEWEB)
Winarno, Nanang, E-mail: nanang-winarno@upi.edu; Prima, Eka Cahya [International Program on Science Education, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, Bandung40154 (Indonesia); Afifah, Ratih Mega Ayu [Department of Physics Education, Post Graduate School, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, Bandung40154 (Indonesia)
2016-02-08
This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled “A New Kind of Science” discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram’s investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.
A hybrid parallel framework for the cellular Potts model simulations
Energy Technology Data Exchange (ETDEWEB)
Jiang, Yi [Los Alamos National Laboratory; He, Kejing [SOUTH CHINA UNIV; Dong, Shoubin [SOUTH CHINA UNIV
2009-01-01
The Cellular Potts Model (CPM) has been widely used for biological simulations. However, most current implementations are either sequential or approximated, which can't be used for large scale complex 3D simulation. In this paper we present a hybrid parallel framework for CPM simulations. The time-consuming POE solving, cell division, and cell reaction operation are distributed to clusters using the Message Passing Interface (MPI). The Monte Carlo lattice update is parallelized on shared-memory SMP system using OpenMP. Because the Monte Carlo lattice update is much faster than the POE solving and SMP systems are more and more common, this hybrid approach achieves good performance and high accuracy at the same time. Based on the parallel Cellular Potts Model, we studied the avascular tumor growth using a multiscale model. The application and performance analysis show that the hybrid parallel framework is quite efficient. The hybrid parallel CPM can be used for the large scale simulation ({approx}10{sup 8} sites) of complex collective behavior of numerous cells ({approx}10{sup 6}).
Multi Car Elevator Control by using Learning Automaton
Shiraishi, Kazuaki; Hamagami, Tomoki; Hirata, Hironori
We study an adaptive control technique for multi car elevators (MCEs) by adopting learning automatons (LAs.) The MCE is a high performance and a near-future elevator system with multi shafts and multi cars. A strong point of the system is that realizing a large carrying capacity in small shaft area. However, since the operation is too complicated, realizing an efficient MCE control is difficult for top-down approaches. For example, “bunching up together" is one of the typical phenomenon in a simple traffic environment like the MCE. Furthermore, an adapting to varying environment in configuration requirement is a serious issue in a real elevator service. In order to resolve these issues, having an autonomous behavior is required to the control system of each car in MCE system, so that the learning automaton, as the solutions for this requirement, is supposed to be appropriate for the simple traffic control. First, we assign a stochastic automaton (SA) to each car control system. Then, each SA varies its stochastic behavior distributions for adapting to environment in which its policy is evaluated with each passenger waiting times. That is LA which learns the environment autonomously. Using the LA based control technique, the MCE operation efficiency is evaluated through simulation experiments. Results show the technique enables reducing waiting times efficiently, and we confirm the system can adapt to the dynamic environment.
Modeling and simulation for train control system using cellular automata
Institute of Scientific and Technical Information of China (English)
LI; KePing; GAO; ZiYou; YANG; LiXing
2007-01-01
Train control system plays a key role in railway traffic. Its function is to manage and control the train movement on railway networks. In our previous works, based on the cellular automata (CA) model, we proposed several models and algorithms for simulating the train movement under different control system conditions. However, these models are only suitable for some simple traffic conditions. Some basic factors, which are important for train movement, are not considered. In this paper, we extend these models and algorithms and give a unified formula. Using the proposed method, we analyze and discuss the space-time diagram of railway traffic flow and the trajectories of the train movement. The numerical simulation and analytical results demonstrate that the unified CA model is an effective tool for simulating the train control system.
Study and Simulation of Traffic Behavior in Cellular Network
Madhup, D. K.; Shrestha, C. L.; Sharma, R. K.
2007-07-01
Cellular radio systems accommodate a large number of users with a limited radio spectrum. The concept of trunking allows a large number of users to share the relatively small number of channels in a cell by providing access to each user, on demand, from a pool of available channels. Traffic engineering deals with provisioning of communication circuits in a given area for a number of subscribers with a required grade of service. Traffic in any cell depends upon the number of users, the average request rate and average call duration. Certain number of channels is required for the required GOS. To design an optimum capacity cellular system, traffic behavior on that system is important. The number of channel required can be estimated by using Erlang formula and Erlang table. Erlang table is not always useful to calculate the probability of blocking in various complex scenarios such as channel borrowing strategies. When the total number of channel available in a given cell are divided to serve partly for newly generated calls and partly for handover calls, and if they use dynamic channel assignment strategies like channel borrowing, then the probability of blocking can't be calculated from Erlang table. Simulation model of the behavior help us to determine the blocking and the channel utilization while using various channel assignment strategies. The title "Study and Simulation of Traffic Behavior in Cellular Network" entail the study of the blocking probability of traffic in cellular network for static channel assignment strategies and dynamic channel borrowing strategies through MATLAB programming language and graphic user interface (GUI). The result shows that the dynamic scheme can perform better than static maximizing the overall utilization of the circuits and minimizing the overall blocking.
Computer simulation of cellular patterning within the Drosophila pupal eye.
Directory of Open Access Journals (Sweden)
David E Larson
Full Text Available We present a computer simulation and associated experimental validation of assembly of glial-like support cells into the interweaving hexagonal lattice that spans the Drosophila pupal eye. This process of cell movements organizes the ommatidial array into a functional pattern. Unlike earlier simulations that focused on the arrangements of cells within individual ommatidia, here we examine the local movements that lead to large-scale organization of the emerging eye field. Simulations based on our experimental observations of cell adhesion, cell death, and cell movement successfully patterned a tracing of an emerging wild-type pupal eye. Surprisingly, altering cell adhesion had only a mild effect on patterning, contradicting our previous hypothesis that the patterning was primarily the result of preferential adhesion between IRM-class surface proteins. Instead, our simulations highlighted the importance of programmed cell death (PCD as well as a previously unappreciated variable: the expansion of cells' apical surface areas, which promoted rearrangement of neighboring cells. We tested this prediction experimentally by preventing expansion in the apical area of individual cells: patterning was disrupted in a manner predicted by our simulations. Our work demonstrates the value of combining computer simulation with in vivo experiments to uncover novel mechanisms that are perpetuated throughout the eye field. It also demonstrates the utility of the Glazier-Graner-Hogeweg model (GGH for modeling the links between local cellular interactions and emergent properties of developing epithelia as well as predicting unanticipated results in vivo.
Cellular automata simulation of medication-induced autoimmune diseases
Stauffer, Dietrich; Proykova, Ana
2004-01-01
We implement the cellular automata model proposed by Stauffer and Weisbuch in 1992 to describe the response of the immune system to antigens in the presence of medications. The model contains two thresholds, θ1 and θ2, suggested by de Boer, Segel, and Perelson to present the minimum field needed to stimulate the proliferation of the receptors and to suppress it, respectively. The influence of the drug is mimicked by increasing the second threshold, thus enhancing the immune response. If this increase is too strong, the immune response is triggered in the whole immune repertoire, causing it to attack the own body. This effect is seen in our simulations to depend both on the ratio of the thresholds and on their absolute values.
APRON: A Cellular Processor Array Simulation and Hardware Design Tool
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David R. W. Barr
2009-01-01
Full Text Available We present a software environment for the efficient simulation of cellular processor arrays (CPAs. This software (APRON is used to explore algorithms that are designed for massively parallel fine-grained processor arrays, topographic multilayer neural networks, vision chips with SIMD processor arrays, and related architectures. The software uses a highly optimised core combined with a flexible compiler to provide the user with tools for the design of new processor array hardware architectures and the emulation of existing devices. We present performance benchmarks for the software processor array implemented on standard commodity microprocessors. APRON can be configured to use additional processing hardware if necessary and can be used as a complete graphical user interface and development environment for new or existing CPA systems, allowing more users to develop algorithms for CPA systems.
Computer simulation of aeolian bedforms
Institute of Scientific and Technical Information of China (English)
苗天德; 慕青松; 武生智
2001-01-01
A discrete model is set up using the cellular automaton method and applied to simulate the formation and evolution of aeolian bedforms. The calculated bedforms resemble the actual shape of natural sand ripples and dunes.This reveals that the sand movement is a typical nonlinear dynamical process, and that the nesting configuration of sand ripples, dunes and draas are a self-organized system with a fractal characteristic, and evotves simultaneously at various scales in the sand-airflow.
Refining cellular automata with routing constraints
Millo, Jean-Vivien; De Simone, Robert
2012-01-01
A cellular automaton (CA) is an infinite array of cells, each containing the same automaton. The dynamics of a CA is distributed over the cells where each computes its next state as a function of the previous states of its neighborhood. Thus, the transmission of such states between neighbors is considered as feasible directly, in no time. When considering the implementation of a cellular automaton on a many-cores System-on-Chip (SoC), this state transmission is no longer abstract and instanta...
Institute of Scientific and Technical Information of China (English)
魏雷; 林鑫; 王猛; 黄卫东
2012-01-01
本文基于MeshTV界面重构算法,发展了二元合金凝固自由枝晶生长的元胞自动机（cellular automaton,CA）模型.通过采用MeshTV界面重构算法,在细化的界面元胞内重构出了固液界面的位置.在此基础上,发展了一种同时适合描述纯物质与合金凝固界面生长的动力学模型.与非界面重构的CA模型相比,本文所发展的模型可以在较大的网格尺寸下实现模型的收敛,同时网格各向异性不明显,且能够反映界面能各向异性参数ε对自由枝晶生长的影响.在ε=0.02时,通过与描述自由枝晶生长的LGK理论模型相比较,发现计算的枝晶尖端速度与LGK理论模型的预测符合较好,而计算的枝晶尖端半径比LGK理论预测值大于约20%.%In this paper, cellular automata （CA） model for free dendritic growth of alloy is presented, in which the interface cell is refined by MeshTV interface reconstruction algorithm. In the present CA model, the growth kinetic for both pure material and alloy is used. The effect of interfacial energy anisotropy parameter e is validated in the CA model. The dendrite tip growth velocity and tip radius are compared with those of the LGK theoretical model, when e = 0.02.
Wall effects on density fluctuations in the GBL thermal lattice gas automaton
Hoekstra, A. G.; Sloot, P. M. A.
2001-12-01
We measure density fluctuations in a 19-bits thermal lattice gas automaton, in the presence of solid walls. The walls have a prominent effect on the dynamic structure factor. Fluctuating hydrodynamics predicts extra peaks in the spectrum. These extra features are indeed observed in the simulated dynamic structure factor.
Simulating Quantitative Cellular Responses Using Asynchronous Threshold Boolean Network Ensembles
Directory of Open Access Journals (Sweden)
Shah Imran
2011-07-01
Full Text Available Abstract Background With increasing knowledge about the potential mechanisms underlying cellular functions, it is becoming feasible to predict the response of biological systems to genetic and environmental perturbations. Due to the lack of homogeneity in living tissues it is difficult to estimate the physiological effect of chemicals, including potential toxicity. Here we investigate a biologically motivated model for estimating tissue level responses by aggregating the behavior of a cell population. We assume that the molecular state of individual cells is independently governed by discrete non-deterministic signaling mechanisms. This results in noisy but highly reproducible aggregate level responses that are consistent with experimental data. Results We developed an asynchronous threshold Boolean network simulation algorithm to model signal transduction in a single cell, and then used an ensemble of these models to estimate the aggregate response across a cell population. Using published data, we derived a putative crosstalk network involving growth factors and cytokines - i.e., Epidermal Growth Factor, Insulin, Insulin like Growth Factor Type 1, and Tumor Necrosis Factor α - to describe early signaling events in cell proliferation signal transduction. Reproducibility of the modeling technique across ensembles of Boolean networks representing cell populations is investigated. Furthermore, we compare our simulation results to experimental observations of hepatocytes reported in the literature. Conclusion A systematic analysis of the results following differential stimulation of this model by growth factors and cytokines suggests that: (a using Boolean network ensembles with asynchronous updating provides biologically plausible noisy individual cellular responses with reproducible mean behavior for large cell populations, and (b with sufficient data our model can estimate the response to different concentrations of extracellular ligands. Our
Simulating the Immune Response on a Distributed Parallel Computer
Castiglione, F.; Bernaschi, M.; Succi, S.
The application of ideas and methods of statistical mechanics to problems of biological relevance is one of the most promising frontiers of theoretical and computational mathematical physics.1,2 Among others, the computer simulation of the immune system dynamics stands out as one of the prominent candidates for this type of investigations. In the recent years immunological research has been drawing increasing benefits from the resort to advanced mathematical modeling on modern computers.3,4 Among others, Cellular Automata (CA), i.e., fully discrete dynamical systems evolving according to boolean laws, appear to be extremely well suited to computer simulation of biological systems.5 A prominent example of immunological CA is represented by the Celada-Seiden automaton, that has proven capable of providing several new insights into the dynamics of the immune system response. To date, the Celada-Seiden automaton was not in a position to exploit the impressive advances of computer technology, and notably parallel processing, simply because no parallel version of this automaton had been developed yet. In this paper we fill this gap and describe a parallel version of the Celada-Seiden cellular automaton aimed at simulating the dynamic response of the immune system. Details on the parallel implementation as well as performance data on the IBM SP2 parallel platform are presented and commented on.
Institute of Scientific and Technical Information of China (English)
张剑; 董力耘
2011-01-01
提出描述交通灯控制下城市道路交通流动力学演化过程的元胞自动机模型,其中交通灯对于路段上车辆的影响是全局的,驾驶员可根据交通灯的状态及时调整驾驶行为,同时还考虑前方车辆的预期运动.该模型中车辆的运动更加平滑,符合实际交通现象.应用模型中的驾驶策略,可以有效地减少怠速和速度骤减的状态,从而减少机动车的尾气排放.%A cellular automaton model is proposed to depict dynamical evolution of urban traffic flow under control of traffic lights on a single-lane road. It is assumed that traffic lights have global influence on vehicles, and drivers adjust their behaviors timely according to the states of traffic light. Furthermore, anticipation effect is taken into account to predict the movement of vehicles in the presence of traffic lights. Therefore vehicles can move forward more smoothly. This is in agreement with the actual situation. It is expected that using the proposed strategy in driving can help reduce vehicle idling and abrupt deceleration and lead to less emission of exhausted gas.
About Strongly Universal Cellular Automata
Directory of Open Access Journals (Sweden)
Maurice Margenstern
2013-09-01
Full Text Available In this paper, we construct a strongly universal cellular automaton on the line with 11 states and the standard neighbourhood. We embed this construction into several tilings of the hyperbolic plane and of the hyperbolic 3D space giving rise to strongly universal cellular automata with 10 states.
Wang, Zhijun; Wang, Jincheng; Li, Junjie; Yang, Gencang; Zhou, Yaohe
2011-10-01
Using a quantitative phase-field model, a systematic investigation of cellular growth in directional solidification is carried out with emphasis on the selection of cellular tip undercooling, tip radius, and cellular spacing. Previous analytical models of cellular growth are evaluated according to the phase-field simulation results. The results show that cellular tip undercooling and tip radius not only depend on the pulling velocity and thermal gradient, but also depend on the cellular interaction related to the cellular spacing. The cellular interaction results in a finite stable range of cellular spacing. The lower limit is determined by the submerging mechanism while the upper limit comes from the tip splitting instability corresponding to the absence of the cellular growth solution, both of which can be obtained from phase-field simulation. Further discussions on the phase-field results also present an analytical method to predict the lower limit. Phase-field simulations on cell elimination between cells with equal spacing validate the finite range of cellular spacing and give deep insight into the cellular doublon and oscillatory instability between cell elimination and tip splitting.
Intuitionistic Fuzzy Automaton for Approximate String Matching
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K.M. Ravi
2014-03-01
Full Text Available This paper introduces an intuitionistic fuzzy automaton model for computing the similarity between pairs of strings. The model details the possible edit operations needed to transform any input (observed string into a target (pattern string by providing a membership and non-membership value between them. In the end, an algorithm is given for approximate string matching and the proposed model computes the similarity and dissimilarity between the pair of strings leading to better approximation.
Numerical simulation of Mach reflection of cellular detonations
Li, J.; Lee, J. H. S.
2016-09-01
The Mach reflection of cellular detonation waves on a wedge is investigated numerically in an attempt to elucidate the effect of cellular instabilities on Mach reflection, the dependence of self-similarity on the thickness of a detonation wave, and the initial development of the Mach stem near the wedge apex. A two-step chain-branching reaction model is used to give a thermally neutral induction zone followed by a chemical reaction zone for the detonation wave. A sufficiently large distance of travel of the Mach stem is computed to observe the asymptotic behavior in the far field. Depending on the scale at which the Mach reflection process occurs, it is found that the Mach reflection of a cellular detonation behaves essentially in the same way as a planar ZND detonation wave. The cellular instabilities, however, cause the triple-point trajectory to fluctuate. The fluctuations are due to interactions of the triple point of the Mach stem with the transverse waves of cellular instabilities. In the vicinity of the wedge apex, the Mach reflection is found to be self-similar and corresponds to that of a shock wave of the same strength, since the Mach stem is highly overdriven initially. In the far field, the triple-point trajectory approaches a straight line, indicating that the Mach reflection becomes self-similar asymptotically. The distance of the approach to self-similarity is found to decrease rapidly with decreasing thickness of the detonation front.
NUMERICAL SIMULATION OF CELLULAR/DENDRITIC PRIMARY SPACING
Institute of Scientific and Technical Information of China (English)
W．Q．Zhang; L．Xiao
2004-01-01
A numerical model has been established to calculate the primary spacing of cellular or dendritic structure with fluid flow considered. The computing results show that the primary spacing depends on the growing velocity, the temperature gradient on the interface and fluid flow. There is a critical growing velocity for the cell-dendrite transition, which has a relationship with the temperature gradient: Rcr=(3-4)×10-9GT. Fluid flow leads to an increase of the primary spacing for dendritic growth but a decrease for cellular growth,resulting in an instability on the interface.
Cellular automata modelling of phase-change memories
Institute of Scientific and Technical Information of China (English)
Wanhua Yu; David Wright
2008-01-01
A novel approach to modelling phase-transition processes in phase change materials used for optical and electrical data storage applications is presented. The model is based on a cellular automaton (CA) approach to predict crystallization behaviour that is linked to thermal and electrical simulations to enable the study of the data writing and erasing processes. The CA approach is shown to be able to predict the evolution of the microstructure during the rapid heating and cooling cycles pertinent to data storage technology, and maps crystallization behaviour on the nanoscale. A simple example based on possible future nonvolatile phase-change random access solid-state memory is presented.
Simulating Quantitative Cellular Responses Using Asynchronous Threshold Boolean Network Ensembles
With increasing knowledge about the potential mechanisms underlying cellular functions, it is becoming feasible to predict the response of biological systems to genetic and environmental perturbations. Due to the lack of homogeneity in living tissues it is difficult to estimate t...
Cellular and Porous Materials Thermal Properties Simulation and Prediction
Öchsner, Andreas; de Lemos, Marcelo J S
2008-01-01
Providing the reader with a solid understanding of the fundamentals as well as an awareness of recent advances in properties and applications of cellular and porous materials, this handbook and ready reference covers all important analytical and numerical methods for characterizing and predicting thermal properties. In so doing it directly addresses the special characteristics of foam-like and hole-riddled materials, combining theoretical and experimental aspects for characterization purposes.
Accelerating cellular automata simulations using AVX and CUDA
Szkoda, Sebastian; Tykierko, Mateusz
2012-01-01
We investigated various methods of parallelization of the Frish-Hasslacher-Pomeau (FHP) cellular automata algorithm for modeling fluid flow. These methods include SSE, AVX, and POSIX Threads for central processing units (CPUs) and CUDA for graphics processing units (GPUs). We present implementation details of the FHP algorithm based on AVX/SSE and CUDA technologies. We found that (a) using AVX or SSE is necessary to fully utilize the potential of modern CPUs; (b) CPUs and GPUs are comparable in terms of computational and economic efficiency only if the CPU code uses AVX or SSE instructions; (c) AVX does not offer any substantial improvement relative to SSE.
Individual Subjective Initiative Merge Model Based on Cellular Automaton
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Yin-Jie Xu
2013-01-01
Full Text Available The merge control models proposed for work zones are classified into two types (Hard Control Merge (HCM model and Soft Control Merge (SCM model according to their own control intensity and are compared with a new model, called Individual Subjective Initiative Merge (ISIM model, which is based on the linear lane-changing probability strategy in the merging area. The attention of this paper is paid to the positive impact of the individual subjective initiative for the whole traffic system. Three models (ISIM, HCM, and SCM are established and compared with each other by two order parameters, that is, system output and average vehicle travel time. Finally, numerical results show that both ISIM and SCM perform better than HCM. Compared with SCM, the output of ISIM is 20 vehicles per hour higher under the symmetric input condition and is more stable under the asymmetric input condition. Meanwhile, the average travel time of ISIM is 2000 time steps less under the oversaturated input condition.
Multiscale simulation of molecular processes in cellular environments.
Chiricotto, Mara; Sterpone, Fabio; Derreumaux, Philippe; Melchionna, Simone
2016-11-13
We describe the recent advances in studying biological systems via multiscale simulations. Our scheme is based on a coarse-grained representation of the macromolecules and a mesoscopic description of the solvent. The dual technique handles particles, the aqueous solvent and their mutual exchange of forces resulting in a stable and accurate methodology allowing biosystems of unprecedented size to be simulated.This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.
Multiscale simulation of molecular processes in cellular environments
Chiricotto, Mara; Sterpone, Fabio; Derreumaux, Philippe; Melchionna, Simone
2016-11-01
We describe the recent advances in studying biological systems via multiscale simulations. Our scheme is based on a coarse-grained representation of the macromolecules and a mesoscopic description of the solvent. The dual technique handles particles, the aqueous solvent and their mutual exchange of forces resulting in a stable and accurate methodology allowing biosystems of unprecedented size to be simulated. This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.
Toward an automaton Constraint for Local Search
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Jun He
2009-10-01
Full Text Available We explore the idea of using finite automata to implement new constraints for local search (this is already a successful technique in constraint-based global search. We show how it is possible to maintain incrementally the violations of a constraint and its decision variables from an automaton that describes a ground checker for that constraint. We establish the practicality of our approach idea on real-life personnel rostering problems, and show that it is competitive with the approach of [Pralong, 2007].
Combining cellular automata and Monte Carlo algorithm to simulate three-dimensional grain growth
Institute of Scientific and Technical Information of China (English)
WANG Wei; CHEN Ju-hua; GUO Pei-quan; ZHAO Ping
2006-01-01
A 3-D simulation of grain growth was conducted by utilizing cellular automata (CA) and Monte Carlo (MC) algorithm. In the simulating procedure, the three-dimensional space is divided into a large number of 2-D isometric planes. Then, each of the planes is divided into identical square cells. Finally, the cellular automata and Monte Carlo algorithm are combined together to simulate the grain growth. Through an evolutionary simulation, the recrystallized microstructure, the grain growth rate and the grain size distribution are acceptably predicted. The simulation routine can be used to simulate the real physical-metallurgy processes and to predict quantitative dynamic information of the evolution of microstructure. Further more, the method is also useful for optimization of materials properties by controlling the microstructure evolution.
Simulation Modeling by Classification of Problems: A Case of Cellular Manufacturing
Afiqah, K. N.; Mahayuddin, Z. R.
2016-02-01
Cellular manufacturing provides good solution approach to manufacturing area by applying Group Technology concept. The evolution of cellular manufacturing can enhance performance of the cell and to increase the quality of the product manufactured but it triggers other problem. Generally, this paper highlights factors and problems which emerge commonly in cellular manufacturing. The aim of the research is to develop a thorough understanding of common problems in cellular manufacturing. A part from that, in order to find a solution to the problems exist using simulation technique, this classification framework is very useful to be adapted during model building. Biology evolution tool was used in the research in order to classify the problems emerge. The result reveals 22 problems and 25 factors using cladistic technique. In this research, the expected result is the cladogram established based on the problems in cellular manufacturing gathered.
Scalable multi-GPU implementation of the MAGFLOW simulator
Directory of Open Access Journals (Sweden)
Giovanni Gallo
2011-12-01
Full Text Available We have developed a robust and scalable multi-GPU (Graphics Processing Unit version of the cellular-automaton-based MAGFLOW lava simulator. The cellular automaton is partitioned into strips that are assigned to different GPUs, with minimal overlapping. For each GPU, a host thread is launched to manage allocation, deallocation, data transfer and kernel launches; the main host thread coordinates all of the GPUs, to ensure temporal coherence and data integrity. The overlapping borders and maximum temporal step need to be exchanged among the GPUs at the beginning of every evolution of the cellular automaton; data transfers are asynchronous with respect to the computations, to cover the introduced overhead. It is not required to have GPUs of the same speed or capacity; the system runs flawlessly on homogeneous and heterogeneous hardware. The speed-up factor differs from that which is ideal (#GPUs× only for a constant overhead loss of about 4E−2 · T · #GPUs, with T as the total simulation time.
Application of cellular automata approach for cloud simulation and rendering
Energy Technology Data Exchange (ETDEWEB)
Christopher Immanuel, W. [Department of Physics, Vel Tech High Tech Dr. Rangarajan Dr. Sakunthala Engineering College, Tamil Nadu, Chennai 600 062 (India); Paul Mary Deborrah, S. [Research Department of Physics, The American College, Tamil Nadu, Madurai 625 002 (India); Samuel Selvaraj, R. [Research Department of Physics, Presidency College, Tamil Nadu, Chennai 600 005 (India)
2014-03-15
Current techniques for creating clouds in games and other real time applications produce static, homogenous clouds. These clouds, while viable for real time applications, do not exhibit an organic feel that clouds in nature exhibit. These clouds, when viewed over a time period, were able to deform their initial shape and move in a more organic and dynamic way. With cloud shape technology we should be able in the future to extend to create even more cloud shapes in real time with more forces. Clouds are an essential part of any computer model of a landscape or an animation of an outdoor scene. A realistic animation of clouds is also important for creating scenes for flight simulators, movies, games, and other. Our goal was to create a realistic animation of clouds.
Macromolecular Chain at a Cellular Surface: a Computer Simulation Model
Xie, Jun; Pandey, Ras
2001-06-01
Computer simulations are performed to study conformation and dynamics of relatively large chain macromolecule at the surface of a model cell membrane - a preliminary attempt to ultimately realistic model for protein on a cell membrane. We use a discrete lattice of size Lx × L × L. The chain molecule of length Lc is modelled by consecutive nodes connected by bonds on the trail of a random walk with appropriate constraints such as excluded volume, energy dependent configurational bias, etc. Monte Carlo method is used to move chains via segmental dynamics, i.e., end-move, kink-jump, crank-shaft, reptation, etc. Membrane substrate is designed by an ensemble of short chains on a flat surface. Large chain molecule is then driven toward the membrane by a field. We plan to examine the dynamics of chain macromolecule, spread of its density, and its conformation.
Experimental investigations and numerical simulations of notch effect in cellular plastic materials
Marsavina, L.; Linul, E.; Voiconi, T.; Negru, R.
2016-04-01
Cellular plastics are light weight structures with many applications in civil, aeronautical, automotive and mechanical engineering. Properties of cellular materials depend on the properties of the solid material, on the shape and dimensions of the cellular structure and on the relative density of the cellular material. Most of cellular plastic materials are crushing in compression and have a brittle behavior in tension. The effect of notches represents an important issue in such materials, taking into account that for packing applications for example, notches/holes should be introduced in the cellular material. This paper investigates the effect of notches in compression for three different densities 100, 145 and 300 kg/m3 polyurethane (PUR) foams. Experimental investigations were performed on rectangular blocks of 100×100×25 mm with 16, 28 and 40 mm central holes. The mechanism of damage was monitored with an IR camera FLIR A40M. Purpose of the numerical simulations was to calibrate a material model, based on compression test for un-notched specimens using the CRUSHABLE FOAM models implemented in ABAQUS SIMULIA. Then the material models were used to simulate the experimental tests on notched blocks. Good agreement was obtained for the load - displacement curves obtained experimentally and from simulation. Also the plastic deformation patterns observed experimentally by IR thermograpghy were obtained numerically using the CRUSHABLE FOAM material model.
Directory of Open Access Journals (Sweden)
Yanni Li
2012-01-01
Full Text Available Searching for the multiple longest common subsequences (MLCS has significant applications in the areas of bioinformatics, information processing, and data mining, and so forth, Although a few parallel MLCS algorithms have been proposed, the efficiency and effectiveness of the algorithms are not satisfactory with the increasing complexity and size of biologic data. To overcome the shortcomings of the existing MLCS algorithms, and considering that MapReduce parallel framework of cloud computing being a promising technology for cost-effective high performance parallel computing, a novel finite automaton (FA based on cloud computing called FACC is proposed under MapReduce parallel framework, so as to exploit a more efficient and effective general parallel MLCS algorithm. FACC adopts the ideas of matched pairs and finite automaton by preprocessing sequences, constructing successor tables, and common subsequences finite automaton to search for MLCS. Simulation experiments on a set of benchmarks from both real DNA and amino acid sequences have been conducted and the results show that the proposed FACC algorithm outperforms the current leading parallel MLCS algorithm FAST-MLCS.
Energy Technology Data Exchange (ETDEWEB)
Mora, Juan Carlos Seck Tuoh [Centro de Investigacion Avanzada en Ingenieria Industrial, Universidad Autonoma del Estado de Hidalgo, Carr Pachuca-Tulancingo Km 4.5, 42020 Pachuca (Mexico); Hernandez, Manuel Gonzalez [Centro de Investigacion Avanzada en Ingenieria Industrial, Universidad Autonoma del Estado de Hidalgo, Carr Pachuca-Tulancingo Km 4.5, 42020 Pachuca (Mexico); Vergara, Sergio V Chapa [Depto de Ingenieria Electrica, Seccion Computacion, Centro de Investigacion y de Estudios Avanzados, Instituto Politecnico Nacional, Av IPN 2508, Col San Pedro Zacatenco, 07300 DF (Mexico)
2003-07-25
Reversible cellular automata are invertible discrete dynamical systems which have been widely studied both for analysing interesting theoretical questions and for obtaining relevant practical applications, for instance, simulating invertible natural systems or implementing data coding devices. An important problem in the theory of reversible automata is to know how the local behaviour which is not invertible is able to yield a reversible global one. In this sense, symbolic dynamics plays an important role for obtaining an adequate representation of a reversible cellular automaton. In this paper we prove the equivalence between a reversible automaton where the ancestors only differ at one side (technically with one of the two Welch indices equal to 1) and a full shift. We represent any reversible automaton by a de Bruijn diagram, and we characterize the way in which the diagram produces an evolution formed by undefined repetitions of two states. By means of amalgamations, we prove that there is always a way of transforming a de Bruijn diagram into the full shift. Finally, we provide an example illustrating the previous results.
Institute of Scientific and Technical Information of China (English)
LI; Xia(黎夏); YEH; Gar-On(叶嘉安)
2002-01-01
This paper discusses the issues about the correlation of spatial variables during spatial decisionmaking using multicriteria evaluation (MCE) and cellular automata (CA). The correlation of spatial variables can cause the malfunction of MCE. In urban simulation, spatial factors often exhibit a high degree of correlation which is considered as an undesirable property for MCE. This study uses principal components analysis (PCA) to remove data redundancy among a large set of spatial variables and determine 'ideal points' for land development. PCA is integrated with cellular automata and geographical information systems (GIS) for the simulation of idealized urban forms for planning purposes.
Intrinsically universal n-dimensional quantum cellular automata
Arrighi, Pablo
2009-01-01
We describe an n-dimensional quantum cellular automaton (QCA) capable of simulating all others, in that the initial configuration and the forward evolution of any n-dimensional QCA can be encoded within the initial configuration of the universal QCA. Several steps of the universal QCA then correspond to one step of the simulated QCA. The simulation preserves the topology in the sense that each cell of the simulated QCA is encoded as a group of adjacent cells in the universal QCA. The encoding is linear and hence does not carry any of the cost of the computation. Part of our proof consists of showing that any QCA can be presented in the more canonical, operational form of a Partitioned QCA, thereby showing an equivalence between many definitions of QCA that are present in the literature.
Directory of Open Access Journals (Sweden)
Paulo Rangel Rios
2009-06-01
Full Text Available Microstructural evolution in three dimensions of nucleation and growth transformations is simulated by means of cellular automata (CA. In the simulation, nuclei are located in space according to a heterogeneous Poisson point processes. The simulation is compared with exact analytical solution recently obtained by Rios and Villa supposing that the intensity is a harmonic function of the spatial coordinate. The simulated data gives very good agreement with the analytical solution provided that the correct shape factor for the growing CA grains is used. This good agreement is auspicious because the analytical expressions were derived and thus are exact only if the shape of the growing regions is spherical.
A cellular automata model for simulating fed-batch penicillin fermentation process
Institute of Scientific and Technical Information of China (English)
Yu Naigong; Ruan Xiaogang
2006-01-01
A cellular automata model to simulate penicillin fed-batch fermentation process(CAPFM)was established in this study,based on a morphologically structured dynamic penicillin production model,that is in turn based on the growth mechanism of penicillin producing microorganisms and the characteristics of penicillin fed-batch fermentation.CAPFM uses the three-dimensional cellular automata as a growth space,and a Moore-type neighborhood as the cellular neighborhood.The transition roles of CAPFM are designed based on mechanical and structural kinetic models of penicillin batch-fed fermentation processes.Every cell of CAPFM represents a single or specific number of penicillin producing microorganisms,and has various state.The simulation experimental results show that CAPFM replicates the evolutionary behavior of penicillin batch-fed fermentation processes described by the structured penicillin production kinetic model accordingly.
Institute of Scientific and Technical Information of China (English)
LI Xin-zhong; GUO Jing-jie; SU Yan-qing; WU Shi-ping; FU Heng-zhi
2005-01-01
A phase-field model whose free energy of the solidification system derived from the Calphad thermodynamic modeling of phase diagram was used to simulate formation of cellular dendrites and fine cellular structures of Ti56Al44 alloy during directional solidification at high growth velocities. The liquid-solid phase transition of L→β was chosen. The dynamics of breakdown of initially planar interfaces into cellular dendrites and fine cellular structures were shown firstly at two growth velocities. Then the unidirectional free growths of two initial nucleations evolving to fine cellular dendrites were investigated. The tip splitting phenomenon is observed and the negative temperature gradient in the liquid represents its supercooling directional solidification. The simulation results show the realistic evolution of interfaces and microstructures and they agree with experimental one.
A federation of simulations based on cellular automata in cyber-physical systems
Directory of Open Access Journals (Sweden)
Hoang Van Tran
2016-02-01
Full Text Available In cyber-physical system (CPS, cooperation between a variety of computational and physical elements usually poses difficulties to current modelling and simulation tools. Although much research has proposed to address those challenges, most solutions do not completely cover uncertain interactions in CPS. In this paper, we present a new approach to federate simulations for CPS. A federation is a combination of, and coordination between simulations upon a standard of communication. In addition, a mixed simulation is defined as several parallel simulations federated in a common time progress. Such simulations run on the models of physical systems, which are built based on cellular automata theory. The experimental results are performed on a federation of three simulations of forest fire spread, river pollution diffusion and wireless sensor network. The obtained results can be utilized to observe and predict the behaviours of physical systems in their interactions.
Parallel Cellular Automata-based simulation of laser dynamics using dynamic load balancing
Guisado, J.L.; Fernández de Vega, F.; Jiménez Morales, F.; Iskra, K.A.; Sloot, P.M.A.; Garnica, Ó.
2008-01-01
In order to analyze the feasibility of executing a parallel bioinspired model of laser dynamics on a heterogeneous non-dedicated cluster, we evaluate its performance including artificial load to simulate other tasks or jobs submitted by other users. As the model is based on a synchronous cellular au
A coarse-grained model for the simulations of biomolecular interactions in cellular environments
Energy Technology Data Exchange (ETDEWEB)
Xie, Zhong-Ru; Chen, Jiawen; Wu, Yinghao, E-mail: yinghao.wu@einstein.yu.edu [Department of Systems and Computational Biology, Albert Einstein College of Medicine of Yeshiva University, 1300 Morris Park Avenue, Bronx, New York 10461 (United States)
2014-02-07
The interactions of bio-molecules constitute the key steps of cellular functions. However, in vivo binding properties differ significantly from their in vitro measurements due to the heterogeneity of cellular environments. Here we introduce a coarse-grained model based on rigid-body representation to study how factors such as cellular crowding and membrane confinement affect molecular binding. The macroscopic parameters such as the equilibrium constant and the kinetic rate constant are calibrated by adjusting the microscopic coefficients used in the numerical simulations. By changing these model parameters that are experimentally approachable, we are able to study the kinetic and thermodynamic properties of molecular binding, as well as the effects caused by specific cellular environments. We investigate the volumetric effects of crowded intracellular space on bio-molecular diffusion and diffusion-limited reactions. Furthermore, the binding constants of membrane proteins are currently difficult to measure. We provide quantitative estimations about how the binding of membrane proteins deviates from soluble proteins under different degrees of membrane confinements. The simulation results provide biological insights to the functions of membrane receptors on cell surfaces. Overall, our studies establish a connection between the details of molecular interactions and the heterogeneity of cellular environments.
[Evaluation of Cellular Effects Caused by Lunar Regolith Simulant Including Fine Particles].
Horie, Masanori; Miki, Takeo; Honma, Yoshiyuki; Aoki, Shigeru; Morimoto, Yasuo
2015-06-01
The National Aeronautics and Space Administration has announced a plan to establish a manned colony on the surface of the moon, and our country, Japan, has declared its participation. The surface of the moon is covered with soil called lunar regolith, which includes fine particles. It is possible that humans will inhale lunar regolith if it is brought into the spaceship. Therefore, an evaluation of the pulmonary effects caused by lunar regolith is important for exploration of the moon. In the present study, we examine the cellular effects of lunar regolith simulant, whose components are similar to those of lunar regolith. We focused on the chemical component and particle size in particular. The regolith simulant was fractionated to effects of fine regolith simulant whose primary particle size is 5.10 μm. These regolith simulants were applied to human lung carcinoma A549 cells at concentrations of 0.1 and 1.0 mg/ml. Cytotoxicity, oxidative stress and immune response were examined after 24 h exposure. Cell membrane damage, mitochondrial dysfunction and induction of Interleukin-8 (IL-8) were observed at the concentration of 1.0 mg/ml. The cellular effects of the regolith simulant at the concentration of 0.1 mg/ml were small, as compared with crystalline silica as a positive control. Secretion of IL-1β and tumor necrosis factor-α (TNF-α) was observed at the concentration of 1.0 mg/ml, but induction of gene expression was not observed at 24 h after exposure. Induction of cellular oxidative stress was small. Although the cellular effects tended to be stronger in the effects of lunar regolith simulant such as cell membrane damage, induction of oxidative stress and proinflammatory effect.
Generic framework for mining cellular automata models on protein-folding simulations.
Diaz, N; Tischer, I
2016-05-13
Cellular automata model identification is an important way of building simplified simulation models. In this study, we describe a generic architectural framework to ease the development process of new metaheuristic-based algorithms for cellular automata model identification in protein-folding trajectories. Our framework was developed by a methodology based on design patterns that allow an improved experience for new algorithms development. The usefulness of the proposed framework is demonstrated by the implementation of four algorithms, able to obtain extremely precise cellular automata models of the protein-folding process with a protein contact map representation. Dynamic rules obtained by the proposed approach are discussed, and future use for the new tool is outlined.
Using Shared Memory As A Cache In High Performance Cellular Automata Water Flow Simulations
Directory of Open Access Journals (Sweden)
Paweł Topa
2013-01-01
Full Text Available Graphics processors (GPU -- Graphic Processor Units recently have gained a lot of interest as an efficient platform for general-purpose computation. Cellular Automata approach which is inherently parallel gives the opportunity to implement high performance simulations. This paper presents how shared memory in GPU can be used to improve performance for Cellular Automata models. In our previous works, we proposed algorithms for Cellular Automata model that use only a GPU global memory. Using a profiling tool, we found bottlenecks in our approach. We introduce modifications that takes an advantage of fast shared memory. The modified algorithm is presented in details, and the results of profiling and performance test are demonstrated. Our unique achievement is comparing the efficiency of the same algorithm working with a global and shared memory.
Simulating three-dimensional hydrodynamics on a cellular-automata machine
Adler, C; Margolus, N H; Rothman, D H; Adler, Christopher; Boghosian, Bruce M; Margolus, Norman; Rothman, Daniel H
1995-01-01
We demonstrate how three-dimensional fluid flow simulations can be carried out on the Cellular Automata Machine 8 (CAM-8), a special-purpose computer for cellular-automata computations. The principal algorithmic innovation is the use of a lattice-gas model with a 16-bit collision operator that is specially adapted to the machine architecture. It is shown how the collision rules can be optimized to obtain a low viscosity of the fluid. Predictions of the viscosity based on a Boltzmann approximation agree well with measurements of the viscosity made on CAM-8. Several test simulations of flows in simple geometries -- channels, pipes, and a cubic array of spheres -- are carried out. Measurements of average flux in these geometries compare well with theoretical predictions.
Mao, Jian; Guo, Ruohai; Yan, Li-Tang
2014-07-01
Clarifying the mechanisms of cellular interactions of graphene family nanomaterials is an urgent issue to the development of guidelines for safer biomedical applications and to the evaluation of health and environment impacts. By combining large-scale computer simulations, theoretical analysis, and experimental discussions, here we present a systematic study on the interactions of graphene nanosheets having various oxidization degrees with a model lipid bilayer membrane. In the mesoscopic simulations, we investigate the detailed translocation pathways of these materials across a 56 × 56 nm(2) membrane patch which allows us to fully consider the role of membrane perturbation during this process. A phase diagram regarding the transmembrane translocation mechanisms of graphene nanosheets is thereby obtained in the space of oxidization degree and particle size. Then, we propose a theoretical approach to analyze the effects of various initial equilibrium states of graphene nanosheets with membrane on their following cellular uptake process. Finally, we demonstrate that the simulation and theoretical results reproduce some important experimental findings towards the mechanisms of cytotoxicity and antibacterial activity of graphene materials. These results not only provide new insight into the cellular internalization mechanism of graphene-based nanomaterials but also offer fundamental understanding on their physicochemical properties which can be precisely tailored for safer biomedical and environment applications.
Modeling Mixed Traffic Flow at Crosswalks in Micro-Simulations Using Cellular Automata
Institute of Scientific and Technical Information of China (English)
DUAN Houli; ZHANG Yi
2007-01-01
The cellular automata (CA) micro-simulation model was used to describe the behavior of the mixed traffic flows at crosswalks where the pedestrians compete with the vehicles to cross the roadway. The focus of this paper is the behavior of pedestrians and the influence of pedestrians' behavior on the vehicle flow, pedestrian flows, and the vehicle waiting time. The proportion of pedestrians who do not obey traffic laws, the group effect, and expected waiting time of pedestrians, regarded as the most important pedestrian characteristics, are taken into consideration in the analysis. Simulation results show the ability of the microsimulation to capture the most important features of mixed traffic flow.
Traffic Cellular Automata Simulation of a Congested Round-About in Mauritius
Fowdur, S. C.; Rughooputh, S. D. D. V.
In this paper a Traffic Cellular Automata (TCA) simulation of a highly congested round-about in Mauritius is performed. The simulations are performed using a multi-cell model that includes anticipation and probability randomization. The simulation model is first calibrated to match actual traffic count statistics taken at the round-about. The topology of the round-about is then modified and the TCA model is used to predict the impact on the congestion level of different changes made. The simulation results enable the assessment of the impact on the traffic density and travel time of the different modifications made. It has been found that the construction of a flyover bridge at the round-about will be the most convenient solution to alleviate congestion and improve the flux significantly.
Kim, Jungkyu; Jensen, Erik C; Stockton, Amanda M; Mathies, Richard A
2013-08-20
A fully integrated multilayer microfluidic chemical analyzer for automated sample processing and labeling, as well as analysis using capillary zone electrophoresis is developed and characterized. Using lifting gate microfluidic control valve technology, a microfluidic automaton consisting of a two-dimensional microvalve cellular array is fabricated with soft lithography in a format that enables facile integration with a microfluidic capillary electrophoresis device. The programmable sample processor performs precise mixing, metering, and routing operations that can be combined to achieve automation of complex and diverse assay protocols. Sample labeling protocols for amino acid, aldehyde/ketone and carboxylic acid analysis are performed automatically followed by automated transfer and analysis by the integrated microfluidic capillary electrophoresis chip. Equivalent performance to off-chip sample processing is demonstrated for each compound class; the automated analysis resulted in a limit of detection of ~16 nM for amino acids. Our microfluidic automaton provides a fully automated, portable microfluidic analysis system capable of autonomous analysis of diverse compound classes in challenging environments.
Automaton based detection of affected cells in three dimensional biological system
Dundas, Jitesh
2011-01-01
The aim of this research review is to propose the logic and search mechanism for the development of an artificially intelligent automaton (AIA) that can find affected cells in a 3-dimensional biological system. Research on the possible application of such automatons to detect and control cancer cells in the human body are greatly focused MRI and PET scans finds the affected regions at the tissue level even as we can find the affected regions at the cellular level using the framework. The AIA may be designed to ensure optimum utilization as they record and might control the presence of affected cells in a human body. The proposed models and techniques can be generalized and used in any application where cells are injured or affected by some disease or accident. The best method to import AIA into the body without surgery or injection is to insert small pill like automata, carrying material viz drugs or leukocytes that is needed to correct the infection. In this process, the AIA can be compared to nano pills to ...
Accountability Analysis of Electronic Commerce Protocols by Finite Automaton Model
Institute of Scientific and Technical Information of China (English)
Xie Xiao-yao; Zhang Huan-guo
2004-01-01
The accountability of electronic commerce protocols is an important aspect to insures security of electronic transaction. This paper proposes to use Finite Automaton (FA) model as a new kind of framework to analyze the trans action protocols in the application of electronic commerce.
Cryptanalysis on a finite automaton public key cryptosystem
Institute of Scientific and Technical Information of China (English)
戴大为; 吴逵; 张焕国
1996-01-01
An attack algorithm is proposed on a finite automaton public key cryptosystem.It is proved that this attack can break FAPKCO in polynomial time.The basic idea can be used in principle to attack other FAPKCs.Therefore,while designing an FAPKC,it must be taken into account whether it is secure or not under this kind of attack.
A Multitarget Land Use Change Simulation Model Based on Cellular Automata and Its Application
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Jun Yang
2014-01-01
Full Text Available Based on the analysis of the existing land use change simulation model, combined with macroland use change driving factors and microlocal land use competition, and through the application of Python language integrated technical approaches such as CA, GIS, AHP, and Markov, a multitarget land use change simulation model based on cellular automata(CA is established. This model was applied to conduct scenario simulation of land use/cover change of the Jinzhou New District, based on 1:10000 map scale land use, planning, topography, statistics, and other data collected in the year of 1988, 2003, and 2012. The simulation results indicate the following: (1 this model can simulate the mutual transformation of multiple land use types in a relatively satisfactory way; it takes land use system as a whole and simultaneously takes the land use demand in the macrolevel and the land use suitability in the local scale into account; and (2 the simulation accuracy of the model reaches 72%, presenting higher creditability. The model is capable of providing auxiliary decision-making support for coastal regions with the analysis of the land use change driving mechanism, prediction of land use change tendencies, and establishment of land resource sustainable utilization policies.
A Vector-based Cellular Automata Model for Simulating Urban Land Use Change
Institute of Scientific and Technical Information of China (English)
LU Yi; CAO Min; ZHANG Lei
2015-01-01
Cellular Automata (CA) is widely used for the simulation of land use changes.This study applied a vector-based CA model to simulate land use change in order to minimize or eliminate the scale sensitivity in traditional raster-based CA model.The cells of vector-based CA model are presented according to the shapes and attributes of geographic entities,and the transition rules of vector-based CA model are improved by taking spatial variables of the study area into consideration.The vector-based CA model is applied to simulate land use changes in downtown of Qidong City,Jiangsu Province,China and its validation is confirmed by the methods of visual assessment and spatial accuracy.The simulation result of vector-based CA model reveals that nearly 75％ of newly increased urban cells are located in the northwest and southwest parts of the study area from 2002 to 2007,which is in consistent with real land use map.In addition,the simulation results of the vector-based and raster-based CA models are compared to real land use data and their spatial accuracies are found to be 84.0％ and 81.9％,respectively.In conclusion,results from this study indicate that the vector-based CA model is a practical and applicable method for the simulation of urbanization processes.
Dendritic grain growth simulation in weld pool of nickel base alloy
Institute of Scientific and Technical Information of China (English)
Zhan Xiaohong; Wei Yanhong; Ma Rui; Dong Zhibo
2008-01-01
Dendritic grain growth at the edge of the weld pool is simulated using a stochastic numerical model of cellular automaton algorithm. The grain growth model is established based upon the balance of solute in the solid/liquid interface of the dendrite tip. Considering the complicated nucleation condition and competitive growth, the dendrite morphologies of different nucleation condition are simulated. The simulated results reproduced the dendrite grain evolution process at the edge of the weld pool. It is indicated that the nucleation condition is an important factor influencing the grain morphologies especially the morphologies of secondary and tertiary arms.
Numerical simulation of microstructure formation of AZ91 using mCA method
Institute of Scientific and Technical Information of China (English)
HE Bo-lin; LI Qiu-ping; QI Qing-yan; YAO Xiang-dong
2006-01-01
A stochastic model for simulating the microstructure formation of Mg alloy AZ91 during solidification was developed based on the finite element method(FEM) for macroscopic model of heat transfer calculation and a modified Cellular Automaton (mCA) for microscopic modeling of nucleation, growth of crystal. In this model, the effect of solute redistribution, interface curvature and preferred orientation was considered. A numerical simulation was developed with C++ program language. The computation was carried out to understand the effect of varying processing parameters, such as nucleation parameters and heat transfer coefficient, on the microstructure formation of AZ91. The result of simulation was displayed on screen.
Simulation of annealing process effect on texture evolution of deep-drawing sheet St15
Institute of Scientific and Technical Information of China (English)
Jinghong Sun; Yazheng Liu; Leyu Zhou
2005-01-01
A two-dimensional cellular automaton method was used to simulate grain growth during the recrystallization annealing of deep-drawing sheet Stl5, taking the simulated result of recrystallization and the experimental result of the annealing texture of deepdrawing sheet St15 as the initial condition and reference. By means of computer simulation, the microstructures and textures of different periods of grain growth were predicted. It is achieved that the grain size, shape and texture become stable after the grain growth at a constant temperature of 700℃ for 10 h, and the advantaged texture components { 111 } and { 111 } are dominant.
Energy Technology Data Exchange (ETDEWEB)
Blazquez, J.S.; Millan, M.; Conde, C.F.; Conde, A. [Departamento de Fisica de la Materia Condensada, Universidad de Sevilla-ICMSE, P.O. Box 1065, 41080 Sevilla (Spain)
2010-05-15
Nanocrystallization kinetics is analyzed in the frame of instantaneous growth approximation, which implies that the time required for a crystallite to reach its final size is negligible with respect to the time required for the nanocrystallization process. This approach strongly simplifies the kinetic analysis and allows us to obtain the nucleation rate from both isothermal and non-isothermal nanocrystallization processes. Moreover, as no constraining mechanism is considered but the absence of growth, the results could be discussed in the frame of Johnson-Mehl-Avrami-Kolmogorov theory with a growth index equal to zero. Cellular automata simulations are in agreement with the observed kinetics and microstructure. (Abstract Copyright [2010], Wiley Periodicals, Inc.)
Czechowski, Zbigniew
2015-07-01
On the basis of simple cellular automaton, the microscopic mechanisms, which can be responsible for elongation of tails of cluster size distributions, were analyzed. It was shown that only the appropriate forms of rebound function can lead to inverse power tails if densities of the grid are small or moderate. For big densities, correlations between clusters become significant and lead to elongation of tails and flattening of the distribution to a straight line in log-log scale. The microscopic mechanism, given by the rebound function, included in simple 1D RDA can be projected on the geometric mechanism, which favours larger clusters in 2D RDA.
Genetic algorithms for determining the parameters of cellular automata in urban simulation
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
This paper demonstrates that cellular automata (CA) can be a useful tool for analyzing the process of many geographical phenomena. There are many studies on using CA to simulate the evolution of cites. Urban dynamics is determined by many spatial variables. The contribution of each spatial variable to the simulation is quantified by its parameter or weight. Calibration procedures are usually required for obtaining a suitable set of parameters so that the realistic urban forms can be simulated. Each parameter has a unique role in controlling urban morphology in the simulation. In this paper, these parameters for urban simulation are determined by using empirical data. Genetic algorithms are used to search for the optimal combination of these parameters. There are spatial variations for urban dynamics in a large region. Distinct sets of parameters can be used to represent the unique features of urban dynamics for various subregions. A further experiment is to evaluate each set of parameters based on the theories of compact cities. It is considered that the better set of parameters can be identified according to the utility function in terms of compact development. This set of parameters can be cloned to other regions to improve overall urban morphology. The original parameters can be also modified to produce more compact urban forms for planning purposes. This approach can provide a useful exploratory tool for testing various planning scenarios for urban development.
Hickmott, Curtis W.
Cellular core tooling is a new technology which has the capability to manufacture complex integrated monolithic composite structures. This novel tooling method utilizes thermoplastic cellular cores as inner tooling. The semi-rigid nature of the cellular cores makes them convenient for lay-up, and under autoclave temperature and pressure they soften and expand providing uniform compaction on all surfaces including internal features such as ribs and spar tubes. This process has the capability of developing fully optimized aerospace structures by reducing or eliminating assembly using fasteners or bonded joints. The technology is studied in the context of evaluating its capabilities, advantages, and limitations in developing high quality structures. The complex nature of these parts has led to development of a model using the Finite Element Analysis (FEA) software Abaqus and the plug-in COMPRO Common Component Architecture (CCA) provided by Convergent Manufacturing Technologies. This model utilizes a "virtual autoclave" technique to simulate temperature profiles, resin flow paths, and ultimately deformation from residual stress. A model has been developed simulating the temperature profile during curing of composite parts made with the cellular core technology. While modeling of composites has been performed in the past, this project will look to take this existing knowledge and apply it to this new manufacturing method capable of building more complex parts and develop a model designed specifically for building large, complex components with a high degree of accuracy. The model development has been carried out in conjunction with experimental validation. A double box beam structure was chosen for analysis to determine the effects of the technology on internal ribs and joints. Double box beams were manufactured and sectioned into T-joints for characterization. Mechanical behavior of T-joints was performed using the T-joint pull-off test and compared to traditional
Changing cellular location of CheZ predicted by molecular simulations.
Directory of Open Access Journals (Sweden)
Karen Lipkow
2006-04-01
Full Text Available In the chemotaxis pathway of the bacterium Escherichia coli, signals are carried from a cluster of receptors to the flagellar motors by the diffusion of the protein CheY-phosphate (CheYp through the cytoplasm. A second protein, CheZ, which promotes dephosphorylation of CheYp, partially colocalizes with receptors in the plasma membrane. CheZ is normally dimeric in solution but has been suggested to associate into highly active oligomers in the presence of CheYp. A model is presented here and supported by Brownian dynamics simulations, which accounts for these and other experimental data: A minority component of the receptor cluster (dimers of CheA(short nucleates CheZ oligomerization and CheZ molecules move from the cytoplasm to a bound state at the receptor cluster depending on the current level of cellular stimulation. The corresponding simulations suggest that dynamic CheZ localization will sharpen cellular responses to chemoeffectors, increase the range of detectable ligand concentrations, and make adaptation more precise and robust. The localization and activation of CheZ constitute a negative feedback loop that provides a second tier of adaptation to the system. Subtle adjustments of this kind are likely to be found in many other signaling pathways.
Institute of Scientific and Technical Information of China (English)
Jia Ning; Ma Shou-Feng; Zhong Shi-Quan
2012-01-01
Previous studies suggest that there are three different jam phases in the cellular automata automaton model with a slow-to-start rule under open boundaries.In the present paper,the dynamics of each free-flow-jam phase transition is studied.By analysing the microscopic behaviour of the traffic flow,we obtain analytical results on the phase transition dynamics.Our results can describe the detailed time evolution of the system during phase transition,while they provide good approximation for the numerical simulation data.These findings can perfectly explain the microscopic mechanism and details of the boundary-triggered phase transition dynamics.
Chen, Qingcai; Shi, Jianghong; Liu, Xiaowei; Wu, Wei; Liu, Bo; Zhang, Hui
2013-03-01
A cellular automata model (CA model) was used to simulate the soil column leaching process of estrogens during the processes of migration and transformation. The results of the simulated leaching experiment showed that the first-order degradation rates of 17α-ethynylestradiol (EE2), 17β-estradiol (E2) and estrone (E1) were 0.131 h- 1 for E2, 0.099 h- 1 for E1 and 0.064 h- 1 for EE2 in the EE2 and E2 leaching process, and the first-order sorption rates were 5.94 h- 1 for E2, 5.63 h- 1 for EE2, 3.125 h- 1 for E1. Their sorption rates were positively correlated with the n-octanol/water partition coefficients. When the diffusion rate was low, its impact on the simulation results was insignificant. The increase in sorption and degradation rates caused the decrease in the total estrogens that leached. In addition, increasing the sorption rate could delay the emerging time of the maximum concentration of estrogen that leached, whereas increasing the degradation rate could shorten the emerging time of the maximum concentration of estrogen that leached. The comparison made between the experimental data and the simulation results of the CA model and the HYDRUS-1D software showed that the establishment of one-component and multi-component CA models could simulate EE2 and E2 soil column leaching processes, and the CA models achieve an intuitive, dynamic, and visual simulation.
Quantum reversibility and a new model of quantum automaton
Ciamarra, M P
2001-01-01
This article is an attempt to generalize the classical theory of reversible computing, principally developed by Bennet [IBM J. Res. Develop., 17(1973)] and by Fredkin and Toffoli [Internat. J. Theoret. Phys., 21(1982)], to the quantum case. This is a fundamental step towards the construction of a quantum computer because a time efficient quantum computation is a reversible physical process. The paper is organized as follows. The first section reviews the classical theory of reversible computing. In the second section it is showed that the designs used in the classical framework to decrease the consumption of space cannot be generalized to the quantum case; it is also suggested that quantum computing is generally more demanding of space than classical computing. In the last section a new model of fully quantum and reversible automaton is proposed. The computational power of this automaton is at least equal to that of classical automata. Some conclusion are drawn in the last section.
Computational energetic model of morphogenesis based on multi-agent Cellular Potts Model.
Tripodi, Sébastien; Ballet, Pascal; Rodin, Vincent
2010-01-01
The Cellular Potts Model (CPM) is a cellular automaton (CA), developed by Glazier and Graner in 1992, to model the morphogenesis. In this model, the entities are the cells. It has already been improved in many ways; however, a key point in biological systems, not defined in CPM, is energetic exchange between entities. We integrate this energetic concept inside the CPM. We simulate a cell differentiation inside a growing cell tissue. The results are the emergence of dynamic patterns coming from the consumption and production of energy. A model described by CA is less scalable than one described by a multi-agent system (MAS). We have developed a MAS based on the CPM, where a cell agent is implemented from the cell of CPM together with several behaviours, in particular the consumption and production of energy from the consumption of molecules.
Modeling and Simulation for Urban Rail Traffic Problem Based on Cellular Automata
Institute of Scientific and Technical Information of China (English)
许琰; 曹成铉; 李明华; 罗金龙
2012-01-01
Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure moving block. We also analyze the characteristics of the urban rail traffic flow under the influence of train density, station dwell times, the length of train, and the train velocity. Train delays can be decreased effectively through flexible departure intervals according to the preceding train type before its departure. The results demonstrate that a suitable adjustment of the current train velocity based on the following train velocity can greatly shorten the minimum departure intervals and then increase the capacity of rail transit.
Simulation of abrasive water jet cutting process: Part 2. Cellular automata approach
Orbanic, Henri; Junkar, Mihael
2004-11-01
A new two-dimensional cellular automata (CA) model for the simulation of the abrasive water jet (AWJ) cutting process is presented. The CA calculates the shape of the cutting front, which can be used as an estimation of the surface quality. The cutting front is formed based on material removal rules and AWJ propagation rules. The material removal rule calculates when a particular part of the material will be removed with regard to the energy of AWJ. The AWJ propagation rule calculates the distribution of AWJ energy through CA by using a weighted average. The modelling with CA also provides a visual narrative of the moving of the cutting front, which is hard to observe in real process. The algorithm is fast and has been successfully tested in comparison to cutting fronts obtained with cutting experiments of aluminium alloy.
Electroacoustic simulation and experiment on a miniature loudspeaker for cellular phones
Huang, Jin H.; Her, Hong-Ching; Shiah, Y. C.; Shin, Shaw-Jyh
2008-02-01
The performance of a miniature loudspeaker used in computer, communication, and consumer electronics products is an integrated function with coupled magnetic, electrical, mechanical, and acoustical fields. Through the finite element method, optimal design parameters to enhance the performance of a miniature loudspeaker are obtained. The sound pressure response of the miniature loudspeaker is simulated by using an equivalent circuit method. Its electrical driver, mechanical motion, and acoustical radiation are analogized by their equivalent elements individually. For the present work, such an analysis is carried out for a miniature loudspeaker manufactured in the cellular phone industry. All speaker parameters in the analysis are experimentally measured. Sound pressure responses are experimentally taken by PULSE Electroacoustics in an anechoic chamber. The equivalent-circuit analysis show fairly good agreement with the experimental results.
Institute of Scientific and Technical Information of China (English)
吴义虎; 李意芬; 喻伟; 喻丹
2014-01-01
The behavior of the driver was considered as the rule of the driver change of lanes,and the new rule of the changes of lanes with the combination between the driver behavior and the coincidental traffic was put forward,then a improved cellular automa-ton model was put forward,the model was proposed to describe the characteristics of co-incidental traffic j ams.By the proposed model,the velocity of traffic flow and the length of vehicle lines by coincidental traffic j ams was simulated,and the results of the simula-tion was proposed.%以元胞自动机模型为基础，在传统的车辆换道规则上，引入驾驶人行为因素，根据不同区域交通流特点和驾驶行为特点，给出了不同的车辆换道规则，建立了一种适用于城市道路偶发性拥堵交通流行为分析的元胞自动机改进模型。并利用该模型，模拟分析了偶发性拥堵发生时不同车流密度的车辆排队和平均车速情况。
Simulating debris flows through a hexagonal cellular automata model: SCIDDICA S3–hex
Directory of Open Access Journals (Sweden)
D. D’Ambrosio
2003-01-01
Full Text Available Cellular Automata (CA represent a formal frame for dynamical systems, which evolve on the base of local interactions. Some types of landslide, such as debris flows, match well this requirement. The latest hexagonal release (S3–hex of the deterministic model SCIDDICA, specifically developed for simulating debris flows, is described. For CA simulation purposes, landslides can be viewed as a dynamical system, subdivided into elementary parts, whose state evolves exclusively as a consequence of local interactions within a spatial and temporal discretum. Space is the world of the CA, here constituted by hexagonal cells. The attributes of each cell ("substates" describe physical characteristics. For computational reasons, the natural phenomenon is "decomposed" into a number of elementary processes, whose proper composition makes up the "transition function" of the CA. By simultaneously applying this function to all the cells, the evolution of the phenomenon can be simulated in terms of modifications of the substates. SCIDDICA S3–hex exhibits a great flexibility in modelling debris flows. With respect to the previous releases of the model, the mechanism of progressive erosion of the soil cover has been added to the transition function. Considered substates are: altitude; thickness and energy of landslide debris; depth of erodable soil cover; debris outflows. Considered elementary processes are: mobilisation triggering and effect (T1, debris outflows (I1, update of landslide debris thickness and energy (I2, and energy loss (T2. Simulations of real debris flows, occurred in Campania (Southern Italy in May 1998 (Sarno and December 1999 (San Martino V.C. and Cervinara, have been performed for model calibration purposes; some examples of analysis are briefly described. Possible applications of the method are: risk mapping, also based on a statistical approach; evaluating the effects of mitigation actions (e.g. stream deviations, topographic
High resolution simulations of energy absorption in dynamically loaded cellular structures
Winter, R. E.; Cotton, M.; Harris, E. J.; Eakins, D. E.; McShane, G.
2017-03-01
Cellular materials have potential application as absorbers of energy generated by high velocity impact. CTH, a Sandia National Laboratories Code which allows very severe strains to be simulated, has been used to perform very high resolution simulations showing the dynamic crushing of a series of two-dimensional, stainless steel metal structures with varying architectures. The structures are positioned to provide a cushion between a solid stainless steel flyer plate with velocities ranging from 300 to 900 m/s, and an initially stationary stainless steel target. Each of the alternative architectures under consideration was formed by an array of identical cells each of which had a constant volume and a constant density. The resolution of the simulations was maximised by choosing a configuration in which one-dimensional conditions persisted for the full period over which the specimen densified, a condition which is most readily met by impacting high density specimens at high velocity. It was found that the total plastic flow and, therefore, the irreversible energy dissipated in the fully densified energy absorbing cell, increase (a) as the structure becomes more rodlike and less platelike and (b) as the impact velocity increases. Sequential CTH images of the deformation processes show that the flow of the cell material may be broadly divided into macroscopic flow perpendicular to the compression direction and jetting-type processes (microkinetic flow) which tend to predominate in rod and rodlike configurations and also tend to play an increasing role at increased strain rates. A very simple analysis of a configuration in which a solid flyer impacts a solid target provides a baseline against which to compare and explain features seen in the simulations. The work provides a basis for the development of energy absorbing structures for application in the 200-1000 m/s impact regime.
Classifying cellular automata using grossone
D'Alotto, Louis
2016-10-01
This paper proposes an application of the Infinite Unit Axiom and grossone, introduced by Yaroslav Sergeyev (see [7] - [12]), to the development and classification of one and two-dimensional cellular automata. By the application of grossone, new and more precise nonarchimedean metrics on the space of definition for one and two-dimensional cellular automata are established. These new metrics allow us to do computations with infinitesimals. Hence configurations in the domain space of cellular automata can be infinitesimally close (but not equal). That is, they can agree at infinitely many places. Using the new metrics, open disks are defined and the number of points in each disk computed. The forward dynamics of a cellular automaton map are also studied by defined sets. It is also shown that using the Infinite Unit Axiom, the number of configurations that follow a given configuration, under the forward iterations of cellular automaton maps, can now be computed and hence a classification scheme developed based on this computation.
Directory of Open Access Journals (Sweden)
Liqiang Ji
2013-01-01
Full Text Available In public places, the high pedestrian density is one of the direct causes leading to crowding and trample disaster, so it is very necessary to investigate the collective and evacuation characteristics for pedestrian movement. In the occupants’ evacuation process, the people-people interaction and the people-environment interaction are sufficiently considered in this paper, which have been divided into the exit attraction, the repulsion force between people, the friction between people, the repulsion force between human and barrier, and the attraction of surrounding people. Through analyzing the existing models, a new occupant evacuation cellular automata (CA model based on the social force model is presented, which overcomes the shortage of the high density crowd simulation and combines the advantages that CA has sample rules and faster calculating speed. The simulating result shows a great applicability for evacuation under the high density crowd condition, and the segregation phenomena have also been found in the bidirectional pedestrian flow. Besides these, setting isolated belt near the exit or entrance of underpass not only remarkably decreases the density and the risk of tramper disaster but also increases the evacuation efficiency, so it provides a new idea for infrastructure design about the exits and entrances.
Stability of Cellular Automata Trajectories Revisited: Branching Walks and Lyapunov Profiles
Baetens, Jan M.; Gravner, Janko
2016-10-01
We study non-equilibrium defect accumulation dynamics on a cellular automaton trajectory: a branching walk process in which a defect creates a successor on any neighborhood site whose update it affects. On an infinite lattice, defects accumulate at different exponential rates in different directions, giving rise to the Lyapunov profile. This profile quantifies instability of a cellular automaton evolution and is connected to the theory of large deviations. We rigorously and empirically study Lyapunov profiles generated from random initial states. We also introduce explicit and computationally feasible variational methods to compute the Lyapunov profiles for periodic configurations, thus developing an analog of Floquet theory for cellular automata.
Simulating Debris Flows Through A Hexagonal Cellular Automata Model: Sciddica (release S3a).
Iovine, G.; di Gregorio, S.; D'Ambrosio, D.; Lupiano, V.; Rongo, R.; Spataro, W.
Cellular Automata (CA) are a powerful tool for modelling natural and artificial sys- tems that can be described in terms of local interactions among their constituent parts. Some types of landslides, such as debris flows, match well this requirement. The general frame and the latest, hexagonal release (S3a) of the deterministic, CA-based model SCIDDICA - specifically developed for simulating debris flows - are described. For simulation purposes, landslides can be viewed as a dynamical system, subdivided into elementary parts, whose state evolves exclusively as a consequence of local in- teractions within a spatial and temporal discretum. Space is the world of the CA, constituted by hexagonal cells. The attributes of each cell (namely "substates") de- scribe their average, physical characteristics. For computational reasons, the natural phenomenon to be simulated is "decomposed" into a number of elementary processes (local interactions), whose proper composition makes up the "transition function" of the CA. By simultaneously applying this function to all the cells, the evolution of the phenomenon can be simulated in terms of modifications of the substates. SCIDDICA- S3a exhibited great flexibility in modelling debris flows. With respect to its previous releases, the mechanism of progressive erosion of the detrital cover has been added to the transition function. Considered substates are: altitude, landslide debris amount and energy, depth and type of detrital cover, water content of the debris, debris out- flows and inflows. Considered elementary processes are: outflows and inflows, energy variation, detrital cover mobilisation, water loss, debris solidification. Simulations of real debris flows, occurred in Campania (Southern Italy) on May 1998 (Sarno) and on December 1999 (San Martino V.C. and Cervinara), are presented. The validation of the model required the best assessment of values to be assigned to empirical param- eters. After that, the application of the
Model checking of time Petri nets using the state class timed automaton
DEFF Research Database (Denmark)
Lime, Didier; Roux, Olivier H.
2006-01-01
In this paper, we propose a method for building the state class graph of a bounded time Petri net (TPN) as a timed automaton (TA), which we call the state class timed automaton. We consider bounded TPN, whose underlying net is not necessarily bounded. We prove that our translation preserves...
Liu, D. R.; Mangelinck-Noël, N.; Gandin, Ch-A.; Zimmermann, G.; Sturz, L.; Nguyen Thi, H.; Billia, B.
2016-03-01
A two-dimensional multi-scale cellular automaton - finite element (CAFE) model is used to simulate grain structure evolution and microsegregation formation during solidification of refined Al-7wt%Si alloys under microgravity. The CAFE simulations are first qualitatively compared with the benchmark experimental data under microgravity. Qualitative agreement is obtained for the position of columnar to equiaxed transition (CET) and the CET transition mode (sharp or progressive). Further comparisons of the distributions of grain elongation factor and equivalent diameter are conducted and reveal a fair quantitative agreement.
Wang, Yang; Chen, Yan-Yan
2016-12-01
The signalized traffic is considerably complex due to the fact that various driving behaviors have emerged to respond to traffic signals. However, the existing cellular automaton models take the signal-vehicle interactions into account inadequately, resulting in a potential risk that vehicular traffic flow dynamics may not be completely explored. To remedy this defect, this paper proposes a more realistic cellular automaton model by incorporating a number of the driving behaviors typically observed when the vehicles are approaching a traffic light. In particular, the anticipatory behavior proposed in this paper is realized with a perception factor designed by considering the vehicle speed implicitly and the gap to its preceding vehicle explicitly. Numerical simulations have been performed based on a signal controlled road which is partitioned into three sections according to the different reactions of drivers. The effects of microscopic driving behaviors on Kerner's time-delayed traffic breakdown at signal (Kerner 2011, 2013) have been investigated with the assistance of spatiotemporal pattern and trajectory analysis. Furthermore, the contributions of the driving behaviors on the traffic breakdown have been statistically examined. Finally, with the activation of the anticipatory behavior, the influences of the other driving behaviors on the formation of platoon have been investigated in terms of the number of platoons, the averaged platoon size, and the averaged flow rate.
Cellular Automata Model for Elastic Solid Material
Institute of Scientific and Technical Information of China (English)
DONG Yin-Feng; ZHANG Guang-Cai; XU Ai-Guo; GAN Yan-Biao
2013-01-01
The Cellular Automaton (CA) modeling and simulation of solid dynamics is a long-standing difficult problem.In this paper we present a new two-dimensional CA model for solid dynamics.In this model the solid body is represented by a set of white and black particles alternatively positioned in the x-and y-directions.The force acting on each particle is represented by the linear summation of relative displacements of the nearest-neighboring particles.The key technique in this new model is the construction of eight coefficient matrices.Theoretical and numerical analyses show that the present model can be mathematically described by a conservative system.So,it works for elastic material.In the continuum limit the CA model recovers the well-known Navier equation.The coefficient matrices are related to the shear module and Poisson ratio of the material body.Compared with previous CA model for solid body,this model realizes the natural coupling of deformations in the x-and y-directions.Consequently,the wave phenomena related to the Poisson ratio effects are successfully recovered.This work advances significantly the CA modeling and simulation in the field of computational solid dynamics.
Directory of Open Access Journals (Sweden)
Kenneth Mubea
2014-01-01
Full Text Available This research explores urban growth based scenarios for the city of Nairobi using a cellular automata urban growth model (UGM. African cities have experienced rapid urbanization over the last decade due to increased population growth and high economic activities. We used multi-temporal Landsat imageries for 1976, 1986, 2000 and 2010 to investigate urban land-use changes in Nairobi. Our UGM used data from urban land-use of 1986 and 2010, road data, slope data and exclusion layer. Monte-Carlo technique was used for model calibration and Multi Resolution Validation (MRV technique for validation. Simulation of urban land-use was done up to the year 2030 when Kenya plans to attain Vision 2030. Three scenarios were explored in the urban modelling process; unmanaged growth with no restriction on environmental areas, managed growth with moderate protection, and a managed growth with maximum protection on forest, agricultural areas, and urban green. Thus alternative scenario development using UGM is useful for planning purposes so as to ensure sustainable development is achieved. UGM provides quantitative, visual, spatial and temporal information which aid policy and decision makers can make informed decisions.
Modeling and Simulation of Polarization in Internet Group Opinions Based on Cellular Automata
Directory of Open Access Journals (Sweden)
Yaofeng Zhang
2015-01-01
Full Text Available Hot events on Internet always attract many people who usually form one or several opinion camps through discussion. For the problem of polarization in Internet group opinions, we propose a new model based on Cellular Automata by considering neighbors, opinion leaders, and external influences. Simulation results show the following: (1 It is easy to form the polarization for both continuous opinions and discrete opinions when we only consider neighbors influence, and continuous opinions are more effective in speeding the polarization of group. (2 Coevolution mechanism takes more time to make the system stable, and the global coupling mechanism leads the system to consensus. (3 Opinion leaders play an important role in the development of consensus in Internet group opinions. However, both taking the opinion leaders as zealots and taking some randomly selected individuals as zealots are not conductive to the consensus. (4 Double opinion leaders with consistent opinions will accelerate the formation of group consensus, but the opposite opinions will lead to group polarization. (5 Only small external influences can change the evolutionary direction of Internet group opinions.
Kinetic Monte Carlo and cellular particle dynamics simulations of multicellular systems
Flenner, Elijah; Janosi, Lorant; Barz, Bogdan; Neagu, Adrian; Forgacs, Gabor; Kosztin, Ioan
2012-03-01
Computer modeling of multicellular systems has been a valuable tool for interpreting and guiding in vitro experiments relevant to embryonic morphogenesis, tumor growth, angiogenesis and, lately, structure formation following the printing of cell aggregates as bioink particles. Here we formulate two computer simulation methods: (1) a kinetic Monte Carlo (KMC) and (2) a cellular particle dynamics (CPD) method, which are capable of describing and predicting the shape evolution in time of three-dimensional multicellular systems during their biomechanical relaxation. Our work is motivated by the need of developing quantitative methods for optimizing postprinting structure formation in bioprinting-assisted tissue engineering. The KMC and CPD model parameters are determined and calibrated by using an original computational-theoretical-experimental framework applied to the fusion of two spherical cell aggregates. The two methods are used to predict the (1) formation of a toroidal structure through fusion of spherical aggregates and (2) cell sorting within an aggregate formed by two types of cells with different adhesivities.
An archived multi-objective simulated annealing for a dynamic cellular manufacturing system
Shirazi, Hossein; Kia, Reza; Javadian, Nikbakhsh; Tavakkoli-Moghaddam, Reza
2014-05-01
To design a group layout of a cellular manufacturing system (CMS) in a dynamic environment, a multi-objective mixed-integer non-linear programming model is developed. The model integrates cell formation, group layout and production planning (PP) as three interrelated decisions involved in the design of a CMS. This paper provides an extensive coverage of important manufacturing features used in the design of CMSs and enhances the flexibility of an existing model in handling the fluctuations of part demands more economically by adding machine depot and PP decisions. Two conflicting objectives to be minimized are the total costs and the imbalance of workload among cells. As the considered objectives in this model are in conflict with each other, an archived multi-objective simulated annealing (AMOSA) algorithm is designed to find Pareto-optimal solutions. Matrix-based solution representation, a heuristic procedure generating an initial and feasible solution and efficient mutation operators are the advantages of the designed AMOSA. To demonstrate the efficiency of the proposed algorithm, the performance of AMOSA is compared with an exact algorithm (i.e., ∈-constraint method) solved by the GAMS software and a well-known evolutionary algorithm, namely NSGA-II for some randomly generated problems based on some comparison metrics. The obtained results show that the designed AMOSA can obtain satisfactory solutions for the multi-objective model.
Yang, Qing-Sheng; Qiao, Ji-Gang; Ai, Bin
2013-09-01
Taking the Dongguan City with rapid urbanization as a case, and selecting landscape ecological security level as evaluation criterion, the urbanization cellular number of 1 km x 1 km ecological security cells was obtained, and imbedded into the transition rules of cellular automata (CA) as the restraint term to control urban development, establish ecological security urban CA, and simulate ecological security urban development pattern. The results showed the integrated landscape ecological security index of the City decreased from 0.497 in 1998 to 0.395 in 2005, indicating that the ecological security at landscape scale was decreased. The CA-simulated integrated ecological security index of the City in 2005 was increased from the measured 0.395 to 0.479, showing that the simulated urban landscape ecological pressure from human became lesser, ecological security became better, and integrated landscape ecological security became higher. CA could be used as an effective tool in researching urban ecological security.
Directory of Open Access Journals (Sweden)
Paulo Rangel Rios
2006-06-01
Full Text Available The effect of non-random nuclei location and the efficiency of microstructural descriptors in assessing such a situation are studied. Cellular automata simulation of recrystallization in two dimensions is carried out to simulate microstrutural evolution for nuclei distribution ranging from a periodic arrangement to clusters of nuclei. The simulation results are compared in detail with microstrutural descriptors normally used to follow transformation evolution. It is shown that the contiguity is particularly relevant to detect microstructural deviations from randomness. This work focuses on recrystallization but its results are applicable to any nucleation and growth transformation.
Game of Life Cellular Automata
Adamatzky, Andrew
2010-01-01
In the late 1960s, British mathematician John Conway invented a virtual mathematical machine that operates on a two-dimensional array of square cell. Each cell takes two states, live and dead. The cells' states are updated simultaneously and in discrete time. A dead cell comes to life if it has exactly three live neighbours. A live cell remains alive if two or three of its neighbours are alive, otherwise the cell dies. Conway's Game of Life became the most programmed solitary game and the most known cellular automaton. The book brings together results of forty years of study into computational
A derives grid-based model for simulation of pedestrian flow
Institute of Scientific and Technical Information of China (English)
Min-jie CHEN; Günter B(A)RWOLFF; Hartmut SCHWANDT
2009-01-01
We present a derived grid-based model for the simulation of pedestrian flow. Interactions among pedestrians are considered as the result of forces within a certain neighbourhood. Unlike the social force model, the forces here, as in Newtonian physics, are proportional to the inverse of the square of the distance. Despite the notion of neighbourhood and the underlying grid, this model differs from the existing cellular automaton (CA) models in that the pedestrians are treated as individuals. Bresenham's algorithm for line rastering is applied in the step calculation.
Speech intelligibility measure for vocal control of an automaton
Naranjo, Michel; Tsirigotis, Georgios
1998-07-01
The acceleration of investigations in Speech Recognition allows to augur, in the next future, a wide establishment of Vocal Control Systems in the production units. The communication between a human and a machine necessitates technical devices that emit, or are submitted to important noise perturbations. The vocal interface introduces a new control problem of a deterministic automaton using uncertain information. The purpose is to place exactly the automaton in a final state, ordered by voice, from an unknown initial state. The whole Speech Processing procedure, presented in this paper, has for input the temporal speech signal of a word and for output a recognised word labelled with an intelligibility index given by the recognition quality. In the first part, we present the essential psychoacoustic concepts for the automatic calculation of the loudness of a speech signal. The architecture of a Time Delay Neural Network is presented in second part where we also give the results of the recognition. The theory of the fuzzy subset, in third part, allows to extract at the same time a recognised word and its intelligibility index. In the fourth part, an Anticipatory System models the control of a Sequential Machine. A prediction phase and an updating one appear which involve data coming from the information system. A Bayesian decision strategy is used and the criterion is a weighted sum of criteria defined from information, minimum path functions and speech intelligibility measure.
Casey, Alex; Iannacchione, Germano; Georgiev, Georgi; Cebe, Peggy
2014-03-01
A computational algorithm has been developed to simulate the transport properties of oriented and un-oriented thin film nanocomposites of isotactic Polypropylene (iPP) and carbon nanotubes (CNT) with increasing CNT concentration. Our goal is to be able to design materials with optimal properties using simulations. We use cellular automata approach in Matlab simulation environment. The percolation threshold is reproduced in the simulations, matching experimental data. Upon percolation, the thermal transport in the films increases sharply, more so for the electrical than for the thermal conductivity, due to the larger difference in the electric conductivities of the CNTs and the polymer. To verify the simulation, the thin-film samples were sheared in the melt at 200 C at 1 Hz in a Linkan microscope shearing hot stage. The thermal and electrical conductivity measurements were performed on the same cell arrangement with the transport perpendicular to the thin-film plane using a DC method. The thermal and electrical conductivity are higher for the un-sheared as compared to the sheared samples with stronger temperature dependence for the latter as compared to the former. Our cellular automata simulations provide information about the microstructure-macroscopic property relation in the thin film nanocomposites and can be extended to simulations of other important materials.
Cellular non-deterministic automata and partial differential equations
Kohler, D.; Müller, J.; Wever, U.
2015-09-01
We define cellular non-deterministic automata (CNDA) in the spirit of non-deterministic automata theory. They are different from the well-known stochastic automata. We propose the concept of deterministic superautomata to analyze the dynamical behavior of a CNDA and show especially that a CNDA can be embedded in a deterministic cellular automaton. As an application we discuss a connection between certain partial differential equations and CNDA.
Gerousis, Costa P.
It is currently predicted that semiconductor device scaling will end at the 22-nm device feature size (7 nm physical channel length) according to the International Technology Roadmap for Semiconductors. The main challenge is then to develop innovative technologies that will extend the scaling beyond roadmap projection. Any new technology must be well matched with complementary metal oxide semiconductor (CMOS) technology and scaleable beyond CMOS scaling projections and must provide low-power high-speed signal processing. Nanotechnology will become an appealing option for developing devices for integrated circuits with dimensions and performances well beyond roadmap predictions. Such devices, based on the controllable transfer of charge between dots or 'islands', can take advantage of the quantum mechanical effects, such as tunneling and energy quantization, which would normally occur at the nanometer scale. An outstanding challenge is in arranging such nanodevices in new architectures that can be integrated on a single chip. In particular, locally interconnected architectures are believed to be necessary to alleviate the problems associated with increasing interconnect length and complexity in ultra-dense circuits. The goal of this work is to investigate the use of nanoelectronic structures in cellular non-linear network (CNN) architectures for potential application in future high-density and low-power CMOS-nanodevice hybrid circuits. The operation of the single-electron tunneling (SET) transistor is first reviewed, followed by a discussion of simple CNN linear architectures using a SET inverter topology as the basis for the non-linear transfer characteristics for individual cells to be used in analog processing arrays for image-processing applications. The basic SET CNN cell acts as a summing node that is capacitively coupled to the inputs and outputs of nearest neighbor cells. Monte Carlo simulation results are used to show CNN-like behavior in attempting to
Lunar Dust and Lunar Simulant Activation, Monitoring, Solution and Cellular Toxicity Properties
Jeevarajan, A.S.; Wallace, W.T.
2009-01-01
perfmed initial tests aimed at understanding the effects of lunar simulant on cellular systems. Alveolar epithelial cells were cultured and exposed to different concentrations of dust suspended in cell culture media. After predetermined amounts of time, the media was removed and the concentrations of important inflammatory cytokines (IL6, IL8, and TNF-alpha ) were measured. The results of these tests are being used to develop the correct protocols for tests to be performed using lunar dust samples.
Floating point based Cellular Automata simulations using a dual FPGA-enabled system
Murtaza, S.; Hoekstra, A.G.; Sloot, P.M.A.; Kindratenko, V.
2008-01-01
With the recent emergence of multicore architectures, the age of multicore computing might have already dawned upon us. This shift might have triggered the evolution of von Neumann architecture towards a parallel processing paradigm. Cellular Automata- inherently decentralized spatially extended sys
Aburas, Maher Milad; Ho, Yuek Ming; Ramli, Mohammad Firuz; Ash'aari, Zulfa Hanan
2016-10-01
In recent years, several types of simulation and prediction models have been used within a GIS environment to determine a realistic future for urban growth patterns. These models include quantitative and spatio-temporal techniques that are implemented to monitor urban growth. The results derived through these techniques are used to create future policies that take into account sustainable development and the demands of future generations. The aim of this paper is to provide a basis for a literature review of urban Cellular Automata (CA) models to find the most suitable approach for a realistic simulation of land use changes. The general characteristics of simulation models of urban growth and urban CA models are described, and the different techniques used in the design of these models are classified. The strengths and weaknesses of the various models are identified based on the analysis and discussion of the characteristics of these models. The results of the review confirm that the CA model is one of the strongest models for simulating urban growth patterns owing to its structure, simplicity, and possibility of evolution. Limitations of the CA model, namely weaknesses in the quantitative aspect, and the inability to include the driving forces of urban growth in the simulation process, may be minimized by integrating it with other quantitative models, such as via the Analytic Hierarchy Process (AHP), Markov Chain and frequency ratio models. Realistic simulation can be achieved when socioeconomic factors and spatial and temporal dimensions are integrated in the simulation process.
Genetic Algorithm Calibration of Probabilistic Cellular Automata for Modeling Mining Permit Activity
Louis, S.J.; Raines, G.L.
2003-01-01
We use a genetic algorithm to calibrate a spatially and temporally resolved cellular automata to model mining activity on public land in Idaho and western Montana. The genetic algorithm searches through a space of transition rule parameters of a two dimensional cellular automata model to find rule parameters that fit observed mining activity data. Previous work by one of the authors in calibrating the cellular automaton took weeks - the genetic algorithm takes a day and produces rules leading to about the same (or better) fit to observed data. These preliminary results indicate that genetic algorithms are a viable tool in calibrating cellular automata for this application. Experience gained during the calibration of this cellular automata suggests that mineral resource information is a critical factor in the quality of the results. With automated calibration, further refinements of how the mineral-resource information is provided to the cellular automaton will probably improve our model.
Directory of Open Access Journals (Sweden)
Castañeda-Camacho Josefina
2015-03-01
Full Text Available The smart antenna technology has received increasing interest due to its capability for improving the performance of wireless radio systems. In this work, we studied the throughput maximization in a digital cellular system when a smart antenna array is implemented. We focus, in the study of the downlink of a 3G cellular system and consider a packet data direct-sequence code division, multiple access (DS-CDMA. Our methodology is based on the Monte Carlo simulation technique, and it is used to show that it is possible to obtain a significant increment in the throughput of the system due to the switched beam smart antenna array. From our results we conclude that it is feasible to consider the application of this technology in 4G environments.
McCune, Matthew; Shafiee, Ashkan; Forgacs, Gabor; Kosztin, Ioan
2014-03-01
Cellular Particle Dynamics (CPD) is an effective computational method for describing and predicting the time evolution of biomechanical relaxation processes of multicellular systems. A typical example is the fusion of spheroidal bioink particles during post bioprinting structure formation. In CPD cells are modeled as an ensemble of cellular particles (CPs) that interact via short-range contact interactions, characterized by an attractive (adhesive interaction) and a repulsive (excluded volume interaction) component. The time evolution of the spatial conformation of the multicellular system is determined by following the trajectories of all CPs through integration of their equations of motion. CPD was successfully applied to describe and predict the fusion of 3D tissue construct involving identical spherical aggregates. Here, we demonstrate that CPD can also predict tissue formation involving uneven spherical aggregates whose volumes decrease during the fusion process. Work supported by NSF [PHY-0957914]. Computer time provided by the University of Missouri Bioinformatics Consortium.
Pattern-oriented Agent-based Monte Carlo simulation of Cellular Redox Environment
DEFF Research Database (Denmark)
Tang, Jiaowei; Holcombe, Mike; Boonen, Harrie C.M.
, that there is a connection between extracellular and intracellular redox [2], whereas others oppose this view [3]. In general however, these experiments lack insight into the dynamics, complex network of reactions and transportation through cell membrane of redox. Therefore, current experimental results reveal......, 2012. 287(7): p. 4397-402. 3. Anderson, C.L., et al., Control of extracellular cysteine/cystine redox state by HT-29 cells is independent of cellular glutathione. Am J Physiol Regul Integr Comp Physiol, 2007. 293(3): p. R1069-75. 4. Go, Y.M. and D.P. Jones, Redox compartmentalization in eukaryotic...
Simulation of the Crashing of Sandwich Structures under Impact Loads by Movable Cellular Automata
Institute of Scientific and Technical Information of China (English)
HUANG De-wu; HUANG Hai; SONG Yi; A I Dmitriev; E V Shilko; S G Psakhie
2005-01-01
Movable cellular automata (MCA) method is applied in the analysis of dynamic characters of ceramic armor composite structures under impact loading. As a new approach, MCA is different from the traditional numerical methods such as the finite element method and boundary element method. Based on the theory of particle mechanics, MCA is applied as a powerful tool in solving specific structural analysis of materials loss and penetrating damages. In this paper the method is used to study responses of multi-layered ceramic plates as a base of armor structures under impact loading, thus assisting further investigations in the crashing process and to improve ceramic armor structures.
Chai, C; Wong, Y D
2014-02-01
At intersection, vehicles coming from different directions conflict with each other. Improper geometric design and signal settings at signalized intersection will increase occurrence of conflicts between road users and results in a reduction of the safety level. This study established a cellular automata (CA) model to simulate vehicular interactions involving right-turn vehicles (as similar to left-turn vehicles in US). Through various simulation scenarios for four case cross-intersections, the relationships between conflict occurrences involving right-turn vehicles with traffic volume and right-turn movement control strategies are analyzed. Impacts of traffic volume, permissive right-turn compared to red-amber-green (RAG) arrow, shared straight-through and right-turn lane as well as signal setting are estimated from simulation results. The simulation model is found to be able to provide reasonable assessment of conflicts through comparison of existed simulation approach and observed accidents. Through the proposed approach, prediction models for occurrences and severity of vehicle conflicts can be developed for various geometric layouts and traffic control strategies.
Efficient Uplink Modeling for Dynamic System-Level Simulations of Cellular and Mobile Networks
Directory of Open Access Journals (Sweden)
Lobinger Andreas
2010-01-01
Full Text Available A novel theoretical framework for uplink simulations is proposed. It allows investigations which have to cover a very long (real- time and which at the same time require a certain level of accuracy in terms of radio resource management, quality of service, and mobility. This is of particular importance for simulations of self-organizing networks. For this purpose, conventional system level simulators are not suitable due to slow simulation speeds far beyond real-time. Simpler, snapshot-based tools are lacking the aforementioned accuracy. The runtime improvements are achieved by deriving abstract theoretical models for the MAC layer behavior. The focus in this work is long term evolution, and the most important uplink effects such as fluctuating interference, power control, power limitation, adaptive transmission bandwidth, and control channel limitations are considered. Limitations of the abstract models will be discussed as well. Exemplary results are given at the end to demonstrate the capability of the derived framework.
Tajik-Mansoury, M. A.; Rajabi, H.; Mazdarani, H.
2017-03-01
The S-value is a standard measure in cellular dosimetry. S-values are calculated by applying analytical methods or by Monte Carlo simulation. In Monte Carlo simulation, particles are either tracked individually event-by-event or close events are condensed and processed collectively in different steps. Both of these methods have been employed for estimation of cellular S-values, but there is no consistency between the published results. In the present paper, we used the Geant4-DNA track-structure physics model as the reference to estimate the cellular S-values. We compared the results with the corresponding values obtained from the following three condensed-history physics models of Geant4: Penelope, Livermore and standard. The geometry and source were exactly the same in all the simulations. We utilized mono-energetic electrons with an initial kinetic energy in the range 1–700 keV as the source of radiation. We also compared our results with the MIRD S-values. We first drew an overall comparison between different data series and then compared the dependence of results on the energy of particles and the size of scoring compartments. The overall comparison indicated a very good linear correlation (R 2 > 91%) and small bias (3%) between the results of the track-structure model and the condensed-history physics model. The bias between MIRD and the results of Monte Carlo track-structure simulation was considerable (‑8%). However, the point-by-point comparison revealed differences of up to 28% between the condensed-history and the track-structure MC codes for self-absorption S-values in the 10–50 keV energy range. For the cross-absorption S-values, the difference was up to 34%. In this energy range, the difference between the MIRD S-values and the Geant4-DNA results was up to 68%. Our findings suggest that the consistency/inconsistency of the results obtained with different MC simulations depends on the size of the scoring volumes, the energy of the
Energy Technology Data Exchange (ETDEWEB)
Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)
2011-07-01
During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)
A tunable cancer cell filter using magnetic beads: cellular and fluid dynamic simulations
Gusenbauer, Markus; Bance, Simon; Exl, Lukas; Reichel, Franz; Oezelt, Harald; Schrefl, Thomas
2011-01-01
In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts functionalized with antibodies for circulating tumor cells. Creating these microposts with interacting magnetic beads makes it possible to tune the geometry in size, position and shape. We develop a simulation tool that combines micromagnetics, discrete particle dynamics and fluid dynamics, in order to design micropost arrays made of interacting beads. For the simulation of blood flow we use the Lattice-Boltzmann method with immersed elastic blood cell models. Parallelization distributes large fluid and particle dynamic simulations over available resources to reduce overall calculation time.
Pattern-oriented Agent-based Monte Carlo simulation of Cellular Redox Environment
DEFF Research Database (Denmark)
Tang, Jiaowei; Holcombe, Mike; Boonen, Harrie C.M.
Research suggests that cellular redox environment could affect the phenotype and function of cells through a complex reaction network[1]. In cells, redox status is mainly regulated by several redox couples, such as Glutathione/glutathione disulfide (GSH/GSSG), Cysteine/ Cystine (CYS......, that there is a connection between extracellular and intracellular redox [2], whereas others oppose this view [3]. In general however, these experiments lack insight into the dynamics, complex network of reactions and transportation through cell membrane of redox. Therefore, current experimental results reveal......] could be very important factors. In our project, an agent-based Monte Carlo modeling [6] is offered to study the dynamic relationship between extracellular and intracellular redox and complex networks of redox reactions. In the model, pivotal redox-related reactions will be included, and the reactants...
Model of Bacterial Conjugation using a Cellular Automaton and Evolutionary Computation
Panche Gutierrez, Stifen
2015-01-01
Resumen. Esta tesis presenta un modelo basado en autómatas celulares y computación evolutiva que permite abstraer el comportamiento de una población bacteriana en un ambiente hóstil. Se define un ecosistema donde convive una población de bacterias y a cada bacteria se le definen un conjunto de propiedades; las bacterias interactúan con el ambiente y con las bacterias que la rodean permitiendo que la colonia bacteriana evolucione. En las bacterias a través de varias generaciones...
Using synchronization to improve the forecasting of large relaxations in a cellular-automaton model
DEFF Research Database (Denmark)
González, Á.; Gómez, J.B.; Vázquez-Prada, M.
2004-01-01
A new forecasting strategy for stochastic systems is introduced. It is inspired by the concept of synchronization, developed in the area of Dynamical Systems, and by the earthquake forecasting algorithms in which different pattern recognition functions are used for identifying seismic premonitory...
2011-11-01
the desired model. 20 5. References 1. Goetz, J. C.; Tan, H.; Renaud, J. E.; Tovar , A. Structural Topology Optimization for Blast Mitigation...Stander, N. A Topology Optimization Tool for LS-DYNA Users: LS- OPT/Topology. The 7th European LS-DYNA Conference, 2009. 10. Tovar , A.; Patel, N
Institute of Scientific and Technical Information of China (English)
于振华; 万鲁河
2014-01-01
以洪河自然保护区1992年、2001年、2010年三期TM遥感影像为数据源，利用C5．0决策树算法从已有的数据及其影响因子数据中挖掘出洪河湿地的演变规则，并将获得的转换规则应用到元胞自动机模型中进行洪河湿地演变的动态模拟与预测，分析和探讨了元胞自动机模型在湿地景观模拟和预测中的重要作用。结果表明，在现有的空间变量和条件不变的情况下，在未来的洪河自然保护区湿地面积将减小，洪河自然保护区干旱化将加重。通过对湿地景观的动态变化模拟和预测研究，能够较好地反映湿地景观的动态变化情况。%In this paper, Hong he Nature Reserve in 1992,2001,2010 three TM image as a data source.C5.0 decision tree algorithm using the data from the existing data mining and its influencing factors of the evolution of rules .Hong he Wetland and the obtained transformation rules applied to the cellular automaton model for the evolution of Hong he Wetland dynamic simulation and forecasting analysis and discussion of cellular automata in simulation and prediction of wetland landscape in an important role The results show that the existing spatial variables and conditions remain unchanged in the future Hong he Nature Reserve wetland area will be reduced . Hong he National Nature Reserve drought will increase .Through the study of the dynamic simulation and prediction of wetland land-scape, to better reflect the dynamic changes of wetland landscape .
Simulation of the dynamics in the magnetotail current sheet
Ojeda, Arian; Calzadilla, Alexander; Savio, Siomel; Alazo, Katy
2013-01-01
The dynamics in the magnetosphere current sheet was simulated following transformations to the rectangular NxM array of cells (cellular automaton) originally proposed by Koselov and Koselova (2002). The magnetosphere part of the modeling system was organized as a rectangular arrangement of cells with a stored energy, a local redistribution of the energy will exist when a value threshold is exceeded in one of the cells. We assume that the threshold value in each cell depends on external control parameter which influences the long boundaries of the rectangular array (40x80). The model dynamics controlled by the z-component of the interplanetary magnetic field (Bz) as well as analogies between the model transient processes and the observed substorm auroral activations are discussed. The Bz correspond to temporary windows of the solar wind for a group of magnetic clouds and plasmoids. The model simulates organized patterns in the energy distribution. The function of distribution of probability (or PDF) of the siz...
Feliciani, Claudio; Nishinari, Katsuhiro
2016-06-01
In this article we present an improved version of the Cellular Automata floor field model making use of a sub-mesh system to increase the maximum density allowed during simulation and reproduce phenomena observed in dense crowds. In order to calibrate the model's parameters and to validate it we used data obtained from an empirical observation of bidirectional pedestrian flow. A good agreement was found between numerical simulation and experimental data and, in particular, the double outflow peak observed during the formation of deadlocks could be reproduced in numerical simulations, thus allowing the analysis of deadlock formation and dissolution. Finally, we used the developed high density model to compute the flow-ratio dependent fundamental diagram of bidirectional flow, demonstrating the instability of balanced flow and predicting the bidirectional flow behavior at very high densities. The model we presented here can be used to prevent dense crowd accidents in the future and to investigate the dynamics of the accidents which already occurred in the past. Additionally, fields such as granular and active matter physics may benefit from the developed framework to study different collective phenomena.
Directory of Open Access Journals (Sweden)
Jun Yang
2013-01-01
Full Text Available Spatiotemporal simulation of tourist town growth is important for research on land use/cover change under the influence of urbanization. Many scholars have shown great interest in the unique pattern of driving urban development with tourism development. Based on the cellular automata (CA model, we simulated and predicted the spatiotemporal growth of Sanpo town in Hebei Province, using the tourism urbanization growth model. Results showed that (1 average annual growth rate of the entire region was 1.5 Ha2 per year from 2005 to 2010, 4 Ha2 per year from 2010 to 2015, and 2.5 Ha2 per year from 2015 to 2020; (2 urban growth rate increased yearly, with regional differences, and had a high degree of correlation with the Euclidean distance of town center, traffic route, attractions, and other factors; (3 Gougezhuang, an important village center in the west of the town, demonstrated traffic advantages and increased growth rate since 2010; (4 Magezhuang village has the largest population in the region, so economic advantages have driven the development of rural urbanization. It showed that CA had high reliability in simulating the spatiotemporal evolution of tourist town, which assists the study of spatiotemporal growth under urbanization and rational protection of tourism resources.
SAR Simulation with Magneto Chiral Effects for Human Head Radiated from Cellular Phones
Torres-Silva, H.
2008-09-01
A numerical method for a microwave signal emitted by a cellular phone, propagating in a magneto-chiral media, characterized by an extended Born-Fedorov formalism, is presented. It is shown that the use of a cell model, combined with a real model of the human head, derived from the magnetic resonance of images allows a good determination of the near fields induced in the head when the brain chirality and the battery magnetic field are considered together. The results on a 2-Dim human head model show the evolution of the specific absorption rate, (SAR coefficient) and the spatial peak specific absorption rate which are sensitives to the magneto-chiral factor, which is important in the brain layer. For GSM/PCN phones, extremely low frequency real pulsed magnetic fields (in the order of 10 to 60 milligauss) are added to the model through the whole of the user's head. The more important conclusion of our work is that the head absorption is bigger than the results for a classical model without the magneto chiral effect. Hot spots are produced due to the combination of microwave and the magnetic field produced by the phone's operation. The FDTD method was used to compute the SARs inside the MRI based head models consisting of various tissues for 1.8 GHz. As a result, we found that in the head model having more than four kinds of tissue, the localized peak SAR reaches maximum inside the head for over five tissues including skin, bone, blood and brain cells.
Signal waveform detection with statistical automaton for internet and web service streaming.
Tseng, Kuo-Kun; Ji, Yuzhu; Liu, Yiming; Huang, Nai-Lun; Zeng, Fufu; Lin, Fang-Ying
2014-01-01
In recent years, many approaches have been suggested for Internet and web streaming detection. In this paper, we propose an approach to signal waveform detection for Internet and web streaming, with novel statistical automatons. The system records network connections over a period of time to form a signal waveform and compute suspicious characteristics of the waveform. Network streaming according to these selected waveform features by our newly designed Aho-Corasick (AC) automatons can be classified. We developed two versions, that is, basic AC and advanced AC-histogram waveform automata, and conducted comprehensive experimentation. The results confirm that our approach is feasible and suitable for deployment.
Signal Waveform Detection with Statistical Automaton for Internet and Web Service Streaming
Directory of Open Access Journals (Sweden)
Kuo-Kun Tseng
2014-01-01
Full Text Available In recent years, many approaches have been suggested for Internet and web streaming detection. In this paper, we propose an approach to signal waveform detection for Internet and web streaming, with novel statistical automatons. The system records network connections over a period of time to form a signal waveform and compute suspicious characteristics of the waveform. Network streaming according to these selected waveform features by our newly designed Aho-Corasick (AC automatons can be classified. We developed two versions, that is, basic AC and advanced AC-histogram waveform automata, and conducted comprehensive experimentation. The results confirm that our approach is feasible and suitable for deployment.
Institute of Scientific and Technical Information of China (English)
CHEN Xu; YU Shi-Xiao; ZHANG Ya-Ping
2013-01-01
Using the fuzzy rule-based classification method,normalized difference vegetation index (NDVI) images acquired from 1982 to 1998 were classified into seventeen phases.Based on these classification images,a probabilistic cellular automata-Markov Chain model was developed and used to simulate a land cover scenario of China for the year 2014.Spatiotemporal dynamics of land use/cover in China from 1982 to 2014 were then analyzed and evaluated.The results showed that the change trends of land cover type from 1998 to 2014 would be contrary to those from 1982 to 1998.In particular,forestland and grassland areas decreased by 1.56％ and 1.46％,respectively,from 1982 to 1998,and should increase by 1.5％ and 2.3％ from 1998 to 2014,respectively.
Cell-centred model for the simulation of curved cellular monolayers
Mosaffa, Payman; Asadipour, Nina; Millán, Daniel; Rodríguez-Ferran, Antonio; J Muñoz, Jose
2015-12-01
This paper presents a cell-centred model for the simulation of planar and curved multicellular soft tissues. We propose a computational model that includes stress relaxation due to cell reorganisation (intercellular connectivity changes) and cytoskeleton remodelling (intracellular changes). Cells are represented by their cell centres, and their mechanical interaction is modelled through active non-linear elastic laws with a dynamically changing resting length. Special attention is paid to the handling of connectivity changes between cells, and the relaxation that the tissues exhibit under these topological changes. Cell-cell connectivity is computed by resorting to a Delaunay triangulation, which is combined with a mapping technique in order to obtain triangulations on curved manifolds. Our numerical results show that even a linear elastic cell-cell interaction model may induce a global non-linear response due to the reorganisation of the cell connectivity. This plastic-like behaviour is combined with a non-linear rheological law where the resting length depends on the elastic strain, mimicking the global visco-elastic response of tissues. The model is applied to simulate the elongation of planar and curved monolayers.
Li, Ye; Yuan, Bing; Yang, Kai; Zhang, Xianren; Yan, Bing; Cao, Dapeng
2017-02-01
The nanoparticles (NPs) functionalized with charged ligands are of particular significance due to their potential drug/gene delivery and biomedical applications. However, the molecular mechanism of endocytosis of the charged NPs by cells, especially the effect of the NP–NP and NP–biomembrane interactions on the internalization pathways is still poorly understood. In this work, we systematically investigate the internalization behaviors of the positively charged NPs by combining experiment technology and dissipative particle dynamics (DPD) simulation. We experimentally find an interesting but highly counterintuitive phenomenon, i.e. the multiple positively charged NPs prefer to enter cells cooperatively although the like-charged NPs have obvious electrostatic repulsion. Furthermore, we adopt the DPD simulation to confirm the experimental findings, and reveal that the mechanism of the cooperative endocytosis between like-charged NPs is definitely caused by the interplay of particle size, the charged ligand density on particle surface and local concentration of NPs. Importantly, we not only observe the normal cooperative endocytosis of like-charged NPs in cell biomembrane like neutral NP case, but also predict the ‘bud’ cooperative endocytosis of like-charged NPs which is absence in the neutral NP case. The results indicate that electrostatic repulsion between the positively charged nanoparticles plays an important role in the ‘bud’ cooperative endocytosis of like-charged NPs.
Idealized Mesoscale Model Simulations of Open Cellular Convection Over the Sea
DEFF Research Database (Denmark)
Vincent, Claire Louise; Hahmann, Andrea N.; Kelly, Mark C.
2012-01-01
version of the model, which excluded the effects of topography, surface inhomogeneities and large-scale weather forcing. Cells with an average diameter of 17.4 km developed. Simulations both with and without a capping inversion were made, and the cell-scale kinetic energy budget was calculated for each...... case. By considering all sources of explicit diffusion in the model, the budgets were balanced. In comparison with previous work based on observational studies, the use of three-dimensional, gridded model data afforded the possibility of calculating all terms in the budgets, which showed...... that the important terms in the budgets were buoyancy, pressure balance and inter-scale transfer to subgrid scales. Cells were also composited to calculate the average cell-scale flow and each of the budget terms on two-dimensional cross-sections through the cells, parallel and perpendicular to the mean wind...
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
This paper presents a development of the extended Cellular Automata (CA), based on relational databases(RDB), to model dynamic interactions among spatial objects. The integration of Geographical Information System (GIS)and CA has the great advantage of simulating geographical processes. But standard CA has some restrictions in cellularshape and neighbourhood and neighbour rules, which restrict the CA's ability to simulate complex, real world environ-ments. This paper discusses a cell's spatial relation based on the spatial object's geometrical and non-geometrical characteris-tics, and extends the cell' s neighbour definition, and considers that the cell' s neighbour lies in the forms of not only spa-tial adjacency but also attribute correlation. This paper then puts forward that spatial relations between two different cellscan be divided into three types, including spatial adjacency, neighbourhood and complicated separation. Based on tradition-al ideas, it is impossible to settle CA's restrictions completely. RDB-based CA is an academic experiment, in whichsome fields are designed to describe the essential information needed to define and select a cell's neighbour. The cultureinnovation diffusion system has multiple forms of space diffusion and inherited characteristics that the RDB-based CA iscapable of simulating more effectively. Finally this paper details a successful case study on the diffusion of fashion weartrends. Compared to the original CA, the RDB-based CA is a more natural and efficient representation of human knowl-edge over space, and is an effective tool in simulating complex systems that have multiple forms of spatial diffusion.
Stochastic simulation of radium-223 dichloride therapy at the sub-cellular level
Gholami, Y.; Zhu, X.; Fulton, R.; Meikle, S.; El-Fakhri, G.; Kuncic, Z.
2015-08-01
Radium-223 dichloride (223Ra) is an alpha particle emitter and a natural bone-seeking radionuclide that is currently used for treating osteoblastic bone metastases associated with prostate cancer. The stochastic nature of alpha emission, hits and energy deposition poses some challenges for estimating radiation damage. In this paper we investigate the distribution of hits to cells by multiple alpha particles corresponding to a typical clinically delivered dose using a Monte Carlo model to simulate the stochastic effects. The number of hits and dose deposition were recorded in the cytoplasm and nucleus of each cell. Alpha particle tracks were also visualized. We found that the stochastic variation in dose deposited in cell nuclei (≃ 40%) can be attributed in part to the variation in LET with pathlength. We also found that ≃ 18% of cell nuclei receive less than one sigma below the average dose per cell (≃ 15.4 Gy). One possible implication of this is that the efficacy of cell kill in alpha particle therapy need not rely solely on ionization clustering on DNA but possibly also on indirect DNA damage through the production of free radicals and ensuing intracellular signaling.
Coordination and Emergence in the Cellular Automated Fashion Game
Cao, Zhigang; Qu, Xinglong; Yang, Mingmin; Yang, Xiaoguang
2012-01-01
We investigate a heterogeneous cellular automaton, where there are two types of agents, conformists and rebels. Each agent has to choose between two actions, 0 and 1. A conformist likes to choose an action that most of her neighbors choose, while in contrast a rebel wants to be different with most of her neighbors. Theoretically, this model is equivalent to the matching pennies game on regular networks. We study the dynamical process by assuming that each agent takes a myopic updating rule. An uniform updating probability is also introduced for each agent to study the whole spectrum from synchronous updating to asynchronous updating. Our model characterizes the phenomenon of fashion very well and has a great potential in the study of the finance and stock markets. A large number of simulations show that in most case agents can reach extraordinarily high degree of coordination. This process is also quite fast and steady. Considering that these dynamics are really simple, agents are selfish, myopic, and have ve...
Directory of Open Access Journals (Sweden)
Ángel Monteagudo
Full Text Available Cancer can be viewed as an emergent behavior in terms of complex system theory and artificial life, Cellular Automata (CA being the tool most used for studying and characterizing the emergent behavior. Different approaches with CA models were used to model cancer growth. The use of the abstract model of acquired cancer hallmarks permits the direct modeling at cellular level, where a cellular automaton defines the mitotic and apoptotic behavior of cells, and allows for an analysis of different dynamics of the cellular system depending on the presence of the different hallmarks. A CA model based on the presence of hallmarks in the cells, which includes a simulation of the behavior of Cancer Stem Cells (CSC and their implications for the resultant growth behavior of the multicellular system, was employed. This modeling of cancer growth, in the avascular phase, was employed to analyze the effect of cancer treatments in a cancer stem cell context. The model clearly explains why, after treatment against non-stem cancer cells, the regrowth capability of CSCs generates a faster regrowth of tumor behavior, and also shows that a continuous low-intensity treatment does not favor CSC proliferation and differentiation, thereby allowing an unproblematic control of future tumor regrowth. The analysis performed indicates that, contrary to the current attempts at CSC control, trying to make CSC proliferation more difficult is an important point to consider, especially in the immediate period after a standard treatment for controlling non-stem cancer cell proliferation.
Institute of Scientific and Technical Information of China (English)
Li Qiang; Guo Qiao-Yi; Li Rong-De
2006-01-01
The dendrite growth and solute microsegregation of Fe-C binary alloy are simulated during solidification process by using cellular automaton method.In the model the solid fraction is deduced from the relationship among the temperature,solute concentration and curvature of the solid/liquid interface unit,which can be expressed as a quadric equation,instead of assuming the interface position and calculating the solid fraction from the interface velocity.Then by using this model a dendrite with O and 45 degree of preferential growth direction are simulated respectively.Furthermore,a solidification microstructure and solute microsegregation are simulated by this method. Finally,different GibbsThomson coefficient and liquid solute diffusing coefficient are adopted to investigate their influences on the morphology of dendrite.
Institute of Scientific and Technical Information of China (English)
ZHU Jinsong; HE Likun
2012-01-01
Abstract In order to accurately simulate the diffusion of chloride ion in the existing concrete bridge and acquire the precise chloride ion concentration at given time,a cellular automata (CA)-based model is proposed.The process of chloride ion diffusion is analyzed by the CA-based method and a nonlinear solution of the Fick's second law is obtained.Considering the impact of various factors such as stress states,temporal and spatial variability of diffusion parameters and water-cement ratio on the process of chloride ion diffusion,the model of chloride ion diffusion under multi-factor coupling actions is presented.A chloride ion penetrating experiment reported in the literature is used to prove the effectiveness and reasonability of the present method,and a T-type beam is taken as an illustrative example to analyze the process of chloride ion diffusion in practical application.The results indicate that CA-based method can simulate the diffusion of chloride ion in the concrete structures with acceptable precision.
Asymptotic Behavior of Excitable Cellular Automata
Durrett, R; Durrett, Richard; Griffeath, David
1993-01-01
Abstract: We study two families of excitable cellular automata known as the Greenberg-Hastings Model (GHM) and the Cyclic Cellular Automaton (CCA). Each family consists of local deterministic oscillating lattice dynamics, with parallel discrete-time updating, parametrized by the range of interaction, the "shape" of its neighbor set, threshold value for contact updating, and number of possible states per site. GHM and CCA are mathematically tractable prototypes for the spatially distributed periodic wave activity of so-called excitable media observed in diverse disciplines of experimental science. Earlier work by Fisch, Gravner, and Griffeath studied the ergodic behavior of these excitable cellular automata on Z^2, and identified two distinct (but closely-related) elaborate phase portraits as the parameters vary. In particular, they noted the emergence of asymptotic phase diagrams (and Euclidean dynamics) in a well-defined threshold-range scaling limit. In this study we present several rigorous results and som...
Liu, Yaolin; Kong, Xuesong; Liu, Yanfang; Chen, Yiyun
2013-01-01
Rapid urbanization in China has triggered the conversion of land from rural to urban use, particularly the conversion of rural settlements to town land. This conversion is the result of the joint effects of the geographic environment and agents involving the government, investors, and farmers. To understand the dynamic interaction dominated by agents and to predict the future landscape of town expansion, a small town land-planning model is proposed based on the integration of multi-agent systems (MAS) and cellular automata (CA). The MAS-CA model links the decision-making behaviors of agents with the neighbor effect of CA. The interaction rules are projected by analyzing the preference conflicts among agents. To better illustrate the effects of the geographic environment, neighborhood, and agent behavior, a comparative analysis between the CA and MAS-CA models in three different towns is presented, revealing interesting patterns in terms of quantity, spatial characteristics, and the coordinating process. The simulation of rural settlements conversion to town land through modeling agent decision and human-environment interaction is very useful for understanding the mechanisms of rural-urban land-use change in developing countries. This process can assist town planners in formulating appropriate development plans.
Indian Academy of Sciences (India)
KAMAL DEEP; PARDEEP K SINGH
2016-09-01
In this paper, an integrated mathematical model of multi-period cell formation and part operation tradeoff in a dynamic cellular manufacturing system is proposed in consideration with multiple part process route. This paper puts emphasize on the production flexibility (production/subcontracting part operation) to satisfy the product demand requirement in different period segments of planning horizon considering production capacity shortage and/or sudden machine breakdown. The proposed model simultaneously generates machine cells and part families and selects the optimum process route instead of the user specifying predetermined routes. Conventional optimization method for the optimal cell formation problem requires substantial amount of time and memory space. Hence a simulated annealing based genetic algorithm is proposed to explore the solution regions efficiently and to expedite the solution search space. To evaluate the computability of the proposed algorithm, different problem scenarios are adopted from literature. The results approve the effectiveness of theproposed approach in designing the manufacturing cell and minimization of the overall cost, considering various manufacturing aspects such as production volume, multiple process route, production capacity, machine duplication, system reconfiguration, material handling and subcontracting part operation.
Directory of Open Access Journals (Sweden)
Xiubin Li
2012-08-01
Full Text Available Ecological land is like the “liver” of a city and is very useful to public health. Ecological land change is a spatially dynamic non-linear process under the interaction between natural and anthropogenic factors at different scales. In this study, by setting up natural development scenario, object orientation scenario and ecosystem priority scenario, a Cellular Automation (CA model has been established to simulate the evolution pattern of ecological land in Beijing in the year 2020. Under the natural development scenario, most of ecological land will be replaced by construction land and crop land. But under the scenarios of object orientation and ecosystem priority, the ecological land area will increase, especially under the scenario of ecosystem priority. When considering the factors such as total area of ecological land, loss of key ecological land and spatial patterns of land use, the scenarios from priority to inferiority are ecosystem priority, object orientation and natural development, so future land management policies in Beijing should be focused on conversion of cropland to forest, wetland protection and prohibition of exploitation of natural protection zones, water source areas and forest parks to maintain the safety of the regional ecosystem.
Continuous limit of a crowd motion and herding model: Analysis and numerical simulations
Pietschmann, Jan-Frederik
2011-11-01
In this paper we study the continuum limit of a cellular automaton model used for simulating human crowds with herding behaviour. We derive a system of non-linear partial differential equations resembling the Keller-Segel model for chemotaxis, however with a non-monotone interaction. The latter has interesting consequences on the behaviour of the model\\'s solutions, which we highlight in its analysis. In particular we study the possibility of stationary states, the formation of clusters and explore their connection to congestion. We also introduce an efficient numerical simulation approach based on an appropriate hybrid discontinuous Galerkin method, which in particular allows flexible treatment of complicated geometries. Extensive numerical studies also provide a better understanding of the strengths and shortcomings of the herding model, in particular we examine trapping effects of crowds behind nonconvex obstacles. © American Institute of Mathematical Sciences.
Cruz, Roberto de la; Guerrero, Pilar; Spill, Fabian; Alarcón, Tomás
2016-10-21
We propose a modelling framework to analyse the stochastic behaviour of heterogeneous, multi-scale cellular populations. We illustrate our methodology with a particular example in which we study a population with an oxygen-regulated proliferation rate. Our formulation is based on an age-dependent stochastic process. Cells within the population are characterised by their age (i.e. time elapsed since they were born). The age-dependent (oxygen-regulated) birth rate is given by a stochastic model of oxygen-dependent cell cycle progression. Once the birth rate is determined, we formulate an age-dependent birth-and-death process, which dictates the time evolution of the cell population. The population is under a feedback loop which controls its steady state size (carrying capacity): cells consume oxygen which in turn fuels cell proliferation. We show that our stochastic model of cell cycle progression allows for heterogeneity within the cell population induced by stochastic effects. Such heterogeneous behaviour is reflected in variations in the proliferation rate. Within this set-up, we have established three main results. First, we have shown that the age to the G1/S transition, which essentially determines the birth rate, exhibits a remarkably simple scaling behaviour. Besides the fact that this simple behaviour emerges from a rather complex model, this allows for a huge simplification of our numerical methodology. A further result is the observation that heterogeneous populations undergo an internal process of quasi-neutral competition. Finally, we investigated the effects of cell-cycle-phase dependent therapies (such as radiation therapy) on heterogeneous populations. In particular, we have studied the case in which the population contains a quiescent sub-population. Our mean-field analysis and numerical simulations confirm that, if the survival fraction of the therapy is too high, rescue of the quiescent population occurs. This gives rise to emergence of resistance
Cellular automata in image processing and geometry
Adamatzky, Andrew; Sun, Xianfang
2014-01-01
The book presents findings, views and ideas on what exact problems of image processing, pattern recognition and generation can be efficiently solved by cellular automata architectures. This volume provides a convenient collection in this area, in which publications are otherwise widely scattered throughout the literature. The topics covered include image compression and resizing; skeletonization, erosion and dilation; convex hull computation, edge detection and segmentation; forgery detection and content based retrieval; and pattern generation. The book advances the theory of image processing, pattern recognition and generation as well as the design of efficient algorithms and hardware for parallel image processing and analysis. It is aimed at computer scientists, software programmers, electronic engineers, mathematicians and physicists, and at everyone who studies or develops cellular automaton algorithms and tools for image processing and analysis, or develops novel architectures and implementations of mass...
SELF-ORGANIZED CRITICALITY AND CELLULAR AUTOMATA
Energy Technology Data Exchange (ETDEWEB)
CREUTZ,M.
2007-01-01
Cellular automata provide a fascinating class of dynamical systems based on very simple rules of evolution yet capable of displaying highly complex behavior. These include simplified models for many phenomena seen in nature. Among other things, they provide insight into self-organized criticality, wherein dissipative systems naturally drive themselves to a critical state with important phenomena occurring over a wide range of length and the scales. This article begins with an overview of self-organized criticality. This is followed by a discussion of a few examples of simple cellular automaton systems, some of which may exhibit critical behavior. Finally, some of the fascinating exact mathematical properties of the Bak-Tang-Wiesenfeld sand-pile model [1] are discussed.
On rational solution of the state equation of a finite automaton
Directory of Open Access Journals (Sweden)
R. Chaudhuri
1988-01-01
Full Text Available We prove that the necessary and sufficient condition for the state equation of a finite automaton M to have a rational solution is that the lexicographical Gödel numbers of the strings belonging to each of the end-sets of M form an ultimately periodic set. A method of determining the existence of a rational solution of the state equation is also given.
基于GPU的元胞自动机熔岩流动模拟%Lava flow simulation in cellular automata based on GPU
Institute of Scientific and Technical Information of China (English)
高超; 孟宪海; 李吉刚; 杨钦
2015-01-01
为解决基于元胞自动机进行熔岩流动模拟的计算效率问题，提出一种应用在元胞自动机上的GPU并行计算方法。将元胞自动机中每一个方形网格映射到GPU的一个逻辑计算单元上，通过并行计算，提高模拟的效率，解决传统串行计算方法的不足，使模拟达到实时性。模拟结果表明，在元胞自动机的物理模型理论基础上，用GPU并行计算进行加速，在模拟效果和时间效率上均取得了良好的效果。%To solve the computing efficiency problem of lava flow simulation based on cellular automata ,a GPU parallel compu‐ting method applied to cellular automata was proposed .Each square mesh in cellular automata was mapped to each core in the GPU .Through GPU parallel computing ,the efficiency of real‐time simulation was improved ,which solved the deficiency of tra‐ditional serial computing .The result demonstrates that lava flow simulation in cellular automata ,with the combination of the GPU parallel computing ,can achieve a high computing efficiency and a better simulation performance .
Ohmori, Shousuke; Yamazaki, Yoshihiro
2016-01-01
Ultradiscrete equations are derived from a set of reaction-diffusion partial differential equations, and cellular automaton rules are obtained on the basis of the ultradiscrete equations. Some rules reproduce the dynamical properties of the original reaction-diffusion equations, namely, bistability and pulse annihilation. Furthermore, other rules bring about soliton-like preservation and periodic pulse generation with a pacemaker, which are not obtained from the original reaction-diffusion equations.
3D similar pattern generation of snow crystals with cellular automata%基于元胞自动化模型的三维雪花晶体近似模式的产生
Institute of Scientific and Technical Information of China (English)
李芳佳; 高尚策; 唐政; 石井雅博; 山下和也
2009-01-01
Computer simulation of snow crystal growing process has been done for many years. Cellular automaton is a computing model which is made from lattice cells and simple rules. Though it is a very simple model, it gives good results when used to imitate complex processes such as the life phenomenon, crystal growth and the turbulent flow. In this paper, a cellular model for 3Dimensional snow crystallization was proposed by extending the traditional 2-Dimensional cellular model. Simulation results indicated that the proposed model can accurately simulate most 3-Dimensional snow erystaUization processes.%关于雪花生长过程的计算机模拟已经受到了广泛关注.其中,元胞自动化模型是一种基于网格和简单规则的计算方法.尽管这是一种简单的模型,但其在模拟复杂过程(比如:生命现象,晶体生长和湍流)时往往能取得较好的结果.提出了一种由传统的二维模型扩展而来的三维雪花晶体生长方法.计算机模拟结果显示提出的方法能够更精确地模拟出三维雪花的晶体化过程.
Microscopic simulation of multi-lane traffic under dynamic tolling and information feedback
Institute of Scientific and Technical Information of China (English)
LIU Tian-liang; HUANG Hai-jun; TIAN Li-jun
2009-01-01
To investigate drivers' lane-changing behavior under different information feedback strategies, a microscopic traffic simulation based on the cellular automaton model was made on the typical freeway with a regular lane and a high-occupancy one. A new dynamic tolling scheme in terms of the real-time traffic condition on the high-occupancy lane was further designed to enhance the whole freeway's flow throughput. The results show that the mean velocity feedback strategy is generally more efficient than the travel time feedback strategy in correctly guiding drivers' lane choice behavior. Specifically, the toll level, lane-changing rate and freeway's throughput and congestion coefficient induced by the travel time feedback strategy oscillate with larger amplitude and longer period. In addition, the dynamic tolling scheme can make the high-occupancy lane less congested and maximize the freeway's throughput when the regular-lane inflow rate is larger than 0.45.
Cellular automata-based tunnel fire simulation%基于元胞自动机的井巷火灾仿真
Institute of Scientific and Technical Information of China (English)
李翠平; 胡磊; 侯定勇; 张佳
2013-01-01
提出了一种基于元胞自动机的井巷火灾可视化仿真方法。在矿井巷道可视化的基础上，通过对火灾元胞进行表征，综合考虑可燃物类型与投放密度、井巷通风、井巷坡度等因素对井巷火源引燃效果的影响及双扩散作用、井巷通风、浮力作用和节流作用等因素对火灾烟气蔓延效果的影响，采用概率函数进行元胞自动机建模，构建了表达元胞温度的井巷火源燃烧模型和表达元胞浓度的井巷火灾烟气蔓延模型。基于火源元胞燃烧演化规则和烟气元胞蔓延演化规则，通过可视化手段展示了井巷火灾火源燃烧和有害气体浓度的时空发展变化。同时以矿山实际数据进行检验，说明了基于元胞自动机的井巷火灾仿真的可行性与有效性。%This article introduces a mine fire visualization simulation method based on cellular automata. On the basis of mine tunnel visualization, a tunnel fire combustion model for expressing cellular temperature and a tunnel fire smoke spread model for expressing cellular concentration were built by fire cell characterization. In these models the influence of fuel type and input density, ventilation and roadway slope on mine fire ignition and the effect of double diffusion, ventilation, buoyancy and throttling on fire smoke spread were taken into account, and a probability function was used for cellular automata modelling. Then according to the fire cellular combustion evolution rules and smoke cellular spreading evolution rules, the spatial changes of tunnel fire burning and harmful gas concentration were demonstrated through visualization means. Actual data from a mine proves the feasibility and effectiveness of tunnel fire simulation based on cellular automata.
Azari, M; Tayyebi, A; Helbich, M; Ahadnejad Reveshty, M
2016-01-01
Urbanization processes challenge the growth of orchards areas in many cities in Iran. In Maragheh orchards are crucial ecological, economical, and tourist sources. To explore orchards threatened by urban expansion, this study aims, first, to develop a new model by coupling cellular automata and arti
A cellular automata model of Ebola virus dynamics
Burkhead, Emily; Hawkins, Jane
2015-11-01
We construct a stochastic cellular automaton (SCA) model for the spread of the Ebola virus (EBOV). We make substantial modifications to an existing SCA model used for HIV, introduced by others and studied by the authors. We give a rigorous analysis of the similarities between models due to the spread of virus and the typical immune response to it, and the differences which reflect the drastically different timing of the course of EBOV. We demonstrate output from the model and compare it with clinical data.
Particle-based Full-band Approach for Fast Simulation of Charge Transport in Si, GaAs, and InP
Directory of Open Access Journals (Sweden)
Marco Saraniti
2002-01-01
Full Text Available We discuss the application of the fullband cellular automaton (CA method for the simulation of charge transport in several semiconductors. Basing the selection of the state after scattering on simple look-up tables, the approach is physically equivalent to the full band Monte Carlo (MC approach but is much faster. Furthermore, the structure of the pre-tabulated transition probabilities naturally allows for an extension of the model to fully anisotropic scattering without additional computational burden. Simulation results of transport of electrons and holes in several materials are discussed, with particular emphasis on the transient response of photo-generated carriers in InP and GaAs. Finally, a discussion on parallel algorithms is presented, for the implementation of the code on workstation clusters.
Tree Automaton Based Algorithms for Sub-Typing and inDOM Relations in XQuery
Institute of Scientific and Technical Information of China (English)
XIE Rong-chuan; XIE Xuan-yang
2004-01-01
Proposed by W3C(World Wide Web Consortium),XQuery is a descriptive query language for XML structured data or documents.The specification of XQuery gives functional description of XQuery's typing system, but doestn't provide methods to judge the Sub-typing and inDOM relations in language compiling.In this paper, both of the two important relations:Sub-typing and inDOM, are described and analyzed.After some definitions of Tree Automaton, the judgment algorithms of these two relations are proposed.
A Continuous-Action Learning Automaton for Stochastic Optimization%一种用于随机优化的连续动作学习自动机
Institute of Scientific and Technical Information of China (English)
刘晓
2015-01-01
Learning automaton( LA) is a stochastic optimization technique where the goal of the automaton is to choose the optimal action out of a set of allowable actions.In most of the existing LA,the action set is finite.Hence,for continuous parameter learning problems,the action space needs to be discretized and the accuracy of the solutions depends on the level of discretization.A new continuous-action learning au-tomaton( CALA) is proposed in this paper.The action set of the automaton is a variable interval,actions are selected according to a uniform distribution over this interval.The two endpoints of the interval are up-dated by using a recently best action which is determined in a manner similar to the simulated annealing scheme.Simulation results are given to show the advantages of the proposed algorithm over three of the existing CALA algorithms for optimization a noise-corrupted,multi-modal function.%学习自动机（ LA）是一种随机优化技术，其中自动机的目标是从一个允许的动作集里选择最优的动作。现有LA的动作集大多都是有限集，因此对于连续参数学习问题，需要将动作空间离散化，并且解的精度取决于离散化的颗粒度。提出一种新的连续动作学习自动机（ CALA），其动作集为一个可变区间，并依照均匀分布选择输出动作。算法通过一种类似提高拟退火的方式确定一个“最新且最好”的动作，并根据该动作对区间的两个端点进行更新。通过优化一个被噪声污损的多模态函数的仿真实验，演示了新算法相对于三种现有的CALA算法的优越性。
Finite Automaton Based Strategy for Automated Trust Negotiation%基于有穷自动机的自动信任协商策略
Institute of Scientific and Technical Information of China (English)
李健利; 刘博; 邓潇
2013-01-01
自动信任协商通过协商策略协调协商双方间访问控制策略、信任证的交互披露以逐步建立信任.现有的访问控制策略规则的理论表示缺乏直观性,在分析和构造策略算法时带来不便.本文将有穷自动机形式化定义与自动信任协商相结合,提出一套基于有穷自动机的信任协商定义体系,并构造有穷自动机状态转换图对相应的访问控制策略进行图形化表示,便于分析和构造协商策略.针对积极策略缺乏安全性和谨慎策略缺乏高效性的问题,提出了基于有穷自动机的协商策略,该策略在谨慎策略的基础上加入记忆链结构,以减少协商双方交互次数,提高协商效率.经证明,该策略具备完备性和安全性,并通过仿真实验证明相对于谨慎策略,该策略具备高效性.%Automated Trust Negotiation is used to gradually establish the trust between strangers by negotiation strategies that coordinate the strangers to iterative disclosure of access control policies and credentials.The theory expression of access control policies'rules lack of the property of directviewing,it goes against to analyze and construct the strategy's algorithm.Through the combination of formal definition of finite automaton with trust negotiation,a new definition system of negotiation based on finite automaton was proposed,and the finite automaton transition diagrams were constructed to represent corresponding access control policies equivalently by graphs,it was propitious to analyze and construct strategies.For problems which the eager strategy lacked security and the prudent strategy lacked high efficiency,a finite automaton based strategy was proposed,which was added to a structure called memory chain on the basis of prudent strategy so as to reduce the frequency of the communication and improve the negotiating efficiency.The strategy was proved to be provided with completeness and safety,and compared with the prudent strategy
Gong, He; Fan, Yubo; Zhang, Ming
2008-04-01
The objective of this paper is to identify the effects of mechanical disuse and basic multi-cellular unit (BMU) activation threshold on the form of trabecular bone during menopause. A bone adaptation model with mechanical- biological factors at BMU level was integrated with finite element analysis to simulate the changes of trabecular bone structure during menopause. Mechanical disuse and changes in the BMU activation threshold were applied to the model for the period from 4 years before to 4 years after menopause. The changes in bone volume fraction, trabecular thickness and fractal dimension of the trabecular structures were used to quantify the changes of trabecular bone in three different cases associated with mechanical disuse and BMU activation threshold. It was found that the changes in the simulated bone volume fraction were highly correlated and consistent with clinical data, and that the trabecular thickness reduced significantly during menopause and was highly linearly correlated with the bone volume fraction, and that the change trend of fractal dimension of the simulated trabecular structure was in correspondence with clinical observations. The numerical simulation in this paper may help to better understand the relationship between the bone morphology and the mechanical, as well as biological environment; and can provide a quantitative computational model and methodology for the numerical simulation of the bone structural morphological changes caused by the mechanical environment, and/or the biological environment.
Institute of Scientific and Technical Information of China (English)
He Gong; Yubo Fan; Ming Zhang
2008-01-01
The objective of this paper is to identify the effects of mechanical disuse and basic multi-cellular unit (BMU) activation threshold on the form of trabecular bone during menopause. A bone adaptation model with mechanical-biological factors at BMU level was integrated with finite element analysis to simulate the changes of trabecular bone structure during menopause. Mechanical disuse and changes in the BMU activation threshold were applied to the model for the period from 4 years before to 4 years after menopause.The changes in bone volume fraction, trabecular thickness and fractal dimension of the trabecular structures were used to quantify the changes of trabecular bone in three different cases associated with mechanical disuse and BMU activation threshold. It was found that the changes in the simulated bone volume fraction were highly correlated and consistent with clinical data, and that the trabecular thickness reduced signi-ficantly during menopause and was highly linearly correlated with the bone volume fraction, and that the change trend of fractal dimension of the simulated trabecular structure was in correspondence with clinical observations. The numerical simulation in this paper may help to better understand the relationship between the bone morphology and the mecha- nical, as well as biological environment; and can provide a quantitative computational model and methodology for the numerical simulation of the bone structural morphological changes caused by the mechanical environment, and/or the biological environment.
Directory of Open Access Journals (Sweden)
M. Thirumaran
2016-04-01
Full Text Available Incorporating changes into the logics of composed services dynamically and successfully is a challenge for sustaining a business’ image and profit in the society, especially when the change is expected to be made immediately at low cost. In this paper, we address this challenge by proposing a change impact analysis framework for long term composed services (LCS which: (i enables the business people to implement the changes by themselves through their analysts, (ii reduces cost and time by eliminating the dependence on IT developers once the application services are developed and delivered, (iii ensures effective incorporation of the changes made by using standard methodologies for evaluation – finite state automaton for verifying the runtime compatibilities and change evaluation and probabilistic cellular automaton for impact analysis and prediction. Through the evaluated probability measures and effective incident matching, the knowledge gained by the analyst over his service logics and the efficiency of incorporating changes are increased.
de la Cruz, Roberto; Spill, Fabian; Alarcón, Tomás
2016-01-01
We propose a modelling framework to analyse the stochastic behaviour of heterogeneous, multi-scale cellular populations. We illustrate our methodology with a particular example in which we study a population with an oxygen-regulated proliferation rate. Our formulation is based on an age-dependent stochastic process. Cells within the population are characterised by their age. The age-dependent (oxygen-regulated) birth rate is given by a stochastic model of oxygen-dependent cell cycle progression. We then formulate an age-dependent birth-and-death process, which dictates the time evolution of the cell population. The population is under a feedback loop which controls its steady state size: cells consume oxygen which in turns fuels cell proliferation. We show that our stochastic model of cell cycle progression allows for heterogeneity within the cell population induced by stochastic effects. Such heterogeneous behaviour is reflected in variations in the proliferation rate. Within this set-up, we have established...
Javaheri Javid, Mohammad Ali; Blackwell, Tim; Zimmer, Robert; Majid al-Rifaie, Mohammad
2016-04-01
Shannon entropy fails to discriminate structurally different patterns in two-dimensional images. We have adapted information gain measure and Kolmogorov complexity to overcome the shortcomings of entropy as a measure of image structure. The measures are customised to robustly quantify the complexity of images resulting from multi-state cellular automata (CA). Experiments with a two-dimensional multi-state cellular automaton demonstrate that these measures are able to predict some of the structural characteristics, symmetry and orientation of CA generated patterns.
Qiu, Menglong; Wang, Qi; Li, Fangbai; Chen, Junjian; Yang, Guoyi; Liu, Liming
2016-01-01
A customized logistic-based cellular automata (CA) model was developed to simulate changes in heavy metal contamination (HMC) in farmland soils of Dongguan, a manufacturing center in Southern China, and to discover the relationship between HMC and related explanatory variables (continuous and categorical). The model was calibrated through the simulation and validation of HMC in 2012. Thereafter, the model was implemented for the scenario simulation of development alternatives for HMC in 2022. The HMC in 2002 and 2012 was determined through soil tests and cokriging. Continuous variables were divided into two groups by odds ratios. Positive variables (odds ratios >1) included the Nemerow synthetic pollution index in 2002, linear drainage density, distance from the city center, distance from the railway, slope, and secondary industrial output per unit of land. Negative variables (odds ratios soil pH, and distance from bodies of water. Categorical variables, including soil type, parent material type, organic content grade, and land use type, also significantly influenced HMC according to Wald statistics. The relative operating characteristic and kappa coefficients were 0.91 and 0.64, respectively, which proved the validity and accuracy of the model. The scenario simulation shows that the government should not only implement stricter environmental regulation but also strengthen the remediation of the current polluted area to effectively mitigate HMC.
Simulation of pedestrian evacuation based on an improved dynamic parameter model
Institute of Scientific and Technical Information of China (English)
Zhu Nuo; Jia Bin; Shao Chun-Fu; Yue Hao
2012-01-01
An improved dynamic parameter model is presented based on cellular automata.The dynamic parameters,including direction parameter,empty parameter,and cognition parameter,are formulated to simplify tactically the process of making decisions for pedestrians.The improved model reflects the judgement of pedestrians on surrounding conditions and the action of choosing or decision.According to the two-dimensional cellular automaton Moore neighborhood we establish the pedestrian moving rule,and carry out corresponding simulations of pedestrian evacuation.The improved model considers the impact of pedestrian density near exits on the evacuation process.Simulated and experimental results demonstrate that the improvement makes sense due to the fact that except for the spatial distance to exits,people also choose an exit according to the pedestrian density around exits.The impact factors α,β,and γ are introduced to describe transition payoff,and their optimal values are determined through simulation.Moreover,the effects of pedestrian distribution,pedestrian density,and the width of exits on the evacuation time are discussed.The optimal exit layout,i.e.,the optimal position and width,is offered.The comparison between the simulated results obtained with the improved model and that from a previous model and experiments indicates that the improved model can reproduce experimental results well.Thus,it has great significance for further study,and important instructional meaning for pedestrian evacuation so as to reduce the number of casualties.
Codd, E F
1968-01-01
Cellular Automata presents the fundamental principles of homogeneous cellular systems. This book discusses the possibility of biochemical computers with self-reproducing capability.Organized into eight chapters, this book begins with an overview of some theorems dealing with conditions under which universal computation and construction can be exhibited in cellular spaces. This text then presents a design for a machine embedded in a cellular space or a machine that can compute all computable functions and construct a replica of itself in any accessible and sufficiently large region of t
Gong, Wenfeng; Yuan, Li; Fan, Wenyi; Stott, Philip
2015-02-01
There have been rapid population and accelerating urban growth with associated changes in land use and soil degradation in northeast China, an important grain-producing region. The development of integrated use of remote sensing, geographic information systems, and combined cellular automata- Markov models has provided new means of assessing changes in land use and land cover, and has enabled projection of trajectories into the future. We applied such techniques to the prefecture-level city of Harbin, the tenth largest city in China. We found that there had been significant losses of the land uses termed "cropland", "grassland", "wetland", and "floodplain" in favour of "built-up land" and lesser transformations from "floodplain" to "forestland" and "water body" over the 18-year period. However, the transition was not a simple process but a complex network of changes, interchanges, and multiple transitions. In the absence of effective land use policies, projection of past trajectories into a balance state in the future would result in the decline of cropland from 65.6% to 46.9% and the increase of built-up area from 7.7% to 23.0% relative to the total area of the prefecture in 1989. It also led to the virtual elimination of land use types such as unused wetland and floodplain.
Directory of Open Access Journals (Sweden)
Zongsheng Zheng
2015-01-01
Full Text Available Environmental factors play an important role in the range expansion of Spartina alterniflora in estuarine salt marshes. CA models focusing on neighbor effect often failed to account for the influence of environmental factors. This paper proposed a CCA model that enhanced CA model by integrating constrain factors of tidal elevation, vegetation density, vegetation classification, and tidal channels in Chongming Dongtan wetland, China. Meanwhile, a positive feedback loop between vegetation and sedimentation was also considered in CCA model through altering the tidal accretion rate in different vegetation communities. After being validated and calibrated, the CCA model is more accurate than the CA model only taking account of neighbor effect. By overlaying remote sensing classification and the simulation results, the average accuracy increases to 80.75% comparing with the previous CA model. Through the scenarios simulation, the future of Spartina alterniflora expansion was analyzed. CCA model provides a new technical idea and method for salt marsh species expansion and control strategies research.
Kim, HyunJin; Choi, Kang-Il
2016-01-01
This paper proposes a pipelined non-deterministic finite automaton (NFA)-based string matching scheme using field programmable gate array (FPGA) implementation. The characteristics of the NFA such as shared common prefixes and no failure transitions are considered in the proposed scheme. In the implementation of the automaton-based string matching using an FPGA, each state transition is implemented with a look-up table (LUT) for the combinational logic circuit between registers. In addition, multiple state transitions between stages can be performed in a pipelined fashion. In this paper, it is proposed that multiple one-to-one state transitions, called merged state transitions, can be performed with an LUT. By cutting down the number of used LUTs for implementing state transitions, the hardware overhead of combinational logic circuits is greatly reduced in the proposed pipelined NFA-based string matching scheme.
Microstructure simulation of rapidly solidified ASP30 high-speed steel particles by gas atomization
Ma, Jie; Wang, Bo; Yang, Zhi-liang; Wu, Guang-xin; Zhang, Jie-yu; Zhao, Shun-li
2016-03-01
In this study, the microstructure evolution of rapidly solidified ASP30 high-speed steel particles was predicted using a simulation method based on the cellular automaton-finite element (CAFE) model. The dendritic growth kinetics, in view of the characteristics of ASP30 steel, were calculated and combined with macro heat transfer calculations by user-defined functions (UDFs) to simulate the microstructure of gas-atomized particles. The relationship among particle diameter, undercooling, and the convection heat transfer coefficient was also investigated to provide cooling conditions for simulations. The simulated results indicated that a columnar grain microstructure was observed in small particles, whereas an equiaxed microstructure was observed in large particles. In addition, the morphologies and microstructures of gas-atomized ASP30 steel particles were also investigated experimentally using scanning electron microscopy (SEM). The experimental results showed that four major types of microstructures were formed: dendritic, equiaxed, mixed, and multi-droplet microstructures. The simulated results and the available experimental data are in good agreement.
基于元胞自动机的海上溢油扩散模拟%Simulation of marine oil spill diffusion based on cellular automata
Institute of Scientific and Technical Information of China (English)
2015-01-01
利用逻辑回归算法和决策树C5.0算法分别获取溢油扩散的转换规则，并构建了基于逻辑回归的CA模型和决策树CA模型。这两个模型仅需要设置起始影像、影响因子和权重等少数的变量，便可以方便地模拟出溢油的动态变化情况。把逻辑回归CA模型和决策树CA模型应用到DeepSpill项目的海上溢油模拟实验，结果表明逻辑回归CA模型的模拟总精度达到96.4%，Kappa系数达0.893，而决策树CA模型的模拟结果更为理想，其精度和kappa系数分别提高了0.2%和0.006。利用元胞自动机能够很好地模拟并预测出海上溢油的动态变化，可以满足对溢油快速响应的要求。%Cellular automata (CA) is an effective tool for simulating geographical process. In this paper, logistic regression and decision tree algorithm (C5.0) are introduced to obtain transition rules, which are used to build logistic regression CA model and decision-tree CA model. These two models are very convenient because they only need a few variables, such as starting image, impact factors and weights. And the simulation results of oil spill can be obtained. The logistic regression CA model and decision-tree CA model are applied to simulate the movement of oil spill in Deep Spill projects. Experiment re-sults showed that the overall accuracy and Kappa coefficient of simulation results in logistic regression CA were 96.4%and 0.893.Better results could be obtained using decision-tree CA model. Its overall accuracy and kappa coefficients increased by 0.2%and 0.006. Our experiment results showed that the CA models could simulate the dynamic changes of the oil spill and meet the requirements for rapid response of governments.
An autonomous operant conditioning automaton%一种自治操作条件反射自动机
Institute of Scientific and Technical Information of China (English)
阮晓钢; 戴丽珍; 于乃功; 于建均
2012-01-01
针对仿生自主学习控制问题,根据自动机的原理,以操作条件反射学习机制为基础,运用仿生的自组织学习方法,提出一种自治操作条件反射自动机(autonomous operant conditioning automata,AOCA)模型,主要包括:操作集合、状态集合、“条件-操作”规则集合、可观测的状态转移以及操作条件反射学习律;定义了基于AOCA状态取向值的操作熵;给出了AOCA操作熵收敛性证明；分析了AOCA自组织特性；规定了AOCA的递归运行程序.同时,将其应用于斯金纳动物实验的模拟,动物分阶段学习,并且成功习得技能,实验结果表明AOCA实现了模拟操作条件反射学习机制.%To deal with the bionic self-organization learning-control problem, on the basis of the automata principle and the operant conditioning learning mechanism, we make use of the bionic self-organization learning method to build an autonomous operant conditioning automaton (AOCA) model including the action set, the state set, the condition-action rule set, the observed state transition, the operant conditioning learning law as well as a recursive program. We also define the operant entropy based on the orientation values of states in the AOCA model, prove the convergence of the AOCA operant entropy, analyze the self-organization characteristics and develop the recursive operation program for the AOCA. The AOCA model has been applied to simulate the Skinner animal experiment, in which the animal learns the task in stages and succeeds in acquiring the skills eventually. These experiment results demonstrate that the AOCA can realize the learning mechanism of operant conditioning.
Institute of Scientific and Technical Information of China (English)
杨周
1996-01-01
Cellular phones, used in automobiles, airliners, and passenger trains, are basically low-power radiotelephones. Calls go through radio transmitters that are located within small geographical units called cells. Because each cell’s signals are too weak to interfere with those of other cells operating on the same fre-
Directory of Open Access Journals (Sweden)
Divya Selvaraj
2014-01-01
Full Text Available Packet content scanning is one of the crucial threats to network security and network monitoring applications. In monitoring applications, payload of packets in a network is matched against the set of patterns in order to detect attacks like worms, viruses, and protocol definitions. During network transfer, incoming and outgoing packets are monitored in depth to inspect the packet payload. In this paper, the regular expressions that are basically string patterns are analyzed for packet payloads in detecting worms. Then the grouping scheme for regular expression matching is rewritten using Deterministic Finite Automaton (DFA. DFA achieves better processing speed during regular expression matching. DFA requires more memory space for each state. In order to reduce memory utilization, decompression technique is used. Delayed Dictionary Compression (DDC is applied for achieving better speeds in the communication links. DDC achieves decoding latency during compression of payload packets in the network. Experimental results show that the proposed approach provides better time consumption and memory utilization during detection of Internet worm attacks.
Directory of Open Access Journals (Sweden)
Pabitra Pal Choudhury
2011-01-01
Full Text Available Dynamics of a nonlinear cellular automaton (CA is, in general asymmetric, irregular, and unpredictable as opposed to that of a linear CA, which is highly systematic and tractable, primarily due to the presence of a matrix handle. In this paper, we present a novel technique of studying the properties of the State Transition Diagram of a nonlinear uniform one-dimensional cellular automaton in terms of its deviation from a suggested linear model. We have considered mainly elementary cellular automata with neighborhood of size three, and, in order to facilitate our analysis, we have classified the Boolean functions of three variables on the basis of number and position(s of bit mismatch with linear rules. The concept of deviant and nondeviant states is introduced, and hence an algorithm is proposed for deducing the State Transition Diagram of a nonlinear CA rule from that of its nearest linear rule. A parameter called the proportion of deviant states is introduced, and its dependence on the length of the CA is studied for a particular class of nonlinear rules.
A new small-world network created by Cellular Automata
Ruan, Yuhong; Li, Anwei
2016-08-01
In this paper, we generate small-world networks by the Cellular Automaton based on starting with one-dimensional regular networks. Besides the common properties of small-world networks with small average shortest path length and large clustering coefficient, the small-world networks generated in this way have other properties: (i) The edges which are cut in the regular network can be controlled that whether the edges are reconnected or not, and (ii) the number of the edges of the small-world network model equals the number of the edges of the original regular network. In other words, the average degree of the small-world network model equals to the average degree of the original regular network.
A cellular automata traffic flow modeling of desired speed variability
Institute of Scientific and Technical Information of China (English)
K.Bentaleb; K.Jetto; H.Ez-Zahraouy; A.Benyoussef
2013-01-01
The satisfaction rate of desired velocity in the case of a mixture of fast and slow vehicles is studied by using a cellular automaton method.It is found that at low density the satisfaction rate depends on the maximal velocity.However,the behavior of the satisfaction rate as a function of the coefficient of variance is independent of the maximal velocity.This is in good agreement with empirical results obtained by Lipshtat [Phys.Rev.E 79 066110 (2009)].Furthermore,our numerical result demonstrates that at low density the satisfaction rate takes higher values,whereas the coefficient of variance is close to zero.The coefficient of variance increases with increasing density,while the satisfaction rate decreases to zero.Moreover,we have also shown that,at low density the coefficient variance depends strongly on the probability of overtaking.
Directory of Open Access Journals (Sweden)
Xu Qingyan
2012-02-01
Full Text Available Directional solidified turbine blades of Ni-based superalloy are widely used as key parts of the gas turbine engines. The mechanical properties of the blade are greatly influenced by the final microstructure and the grain orientation determined directly by the grain selector geometry of the casting. In this paper, mathematical models were proposed for three dimensional simulation of the grain growth and microstructure evolution in directional solidification of turbine blade casting. Ray-tracing method was applied to calculate the temperature variation of the blade. Based on the thermo model of heat transfer, the competitive grain growth within the starter block and the spiral of the grain selector, the grain growth in the blade and the microstructure evolution were simulated via a modified Cellular Automaton method. Validation experiments were carried out, and the measured results were compared quantitatively with the predicted results. The simulated cooling curves and microstructures corresponded well with the experimental results. The proposed models could be used to predict the grain morphology and the competitive grain evolution during directional solidification.
Modeling evolution and immune system by cellular automata
Energy Technology Data Exchange (ETDEWEB)
Bezzi, M. [Scuola Internazionale Superiore di Studi Avanzati, Trieste (Italy); Istituto Nazionale di Fisica della Materia, Florence (Italy)
2001-07-01
In this review the behavior of two different biological systems is investigated using cellular automata. Starting from this spatially extended approach it is also tried, in some cases, to reduce the complexity of the system introducing mean-field approximation, and solving (or trying to solve) these simplified systems. It is discussed the biological meaning of the results, the comparison with experimental data (if available) and the different features between spatially extended and mean-field versions. The biological systems considered in this review are the following: Darwinian evolution in simple ecosystems and immune system response. In the first section the main features of molecular evolution are introduced, giving a short survey of genetics for physicists and discussing some models for prebiotic systems and simple ecosystems. It is also introduced a cellular automaton model for studying a set of evolving individuals in a general fitness landscape, considering also the effects of co-evolution. In particular the process of species formation (speciation) is described in sect. 5. The second part deals with immune system modeling. The biological features of immune response are discussed, as well as it is introduced the concept of shape space and of idiotypic network. More detailed reviews which deal with immune system models (mainly focused on idiotypic network models) can be found. Other themes here discussed: the applications of CA to immune system modeling, two complex cellular automata for humoral and cellular immune response. Finally, it is discussed the biological data and the general conclusions are drawn in the last section.
MIMO Communication for Cellular Networks
Huang, Howard; Venkatesan, Sivarama
2012-01-01
As the theoretical foundations of multiple-antenna techniques evolve and as these multiple-input multiple-output (MIMO) techniques become essential for providing high data rates in wireless systems, there is a growing need to understand the performance limits of MIMO in practical networks. To address this need, MIMO Communication for Cellular Networks presents a systematic description of MIMO technology classes and a framework for MIMO system design that takes into account the essential physical-layer features of practical cellular networks. In contrast to works that focus on the theoretical performance of abstract MIMO channels, MIMO Communication for Cellular Networks emphasizes the practical performance of realistic MIMO systems. A unified set of system simulation results highlights relative performance gains of different MIMO techniques and provides insights into how best to use multiple antennas in cellular networks under various conditions. MIMO Communication for Cellular Networks describes single-user,...
Directory of Open Access Journals (Sweden)
Banjanovic-Mehmedovic Lejla
2016-01-01
Full Text Available Accurate prediction of traffic information is important in many applications in relation to Intelligent Transport systems (ITS, since it reduces the uncertainty of future traffic states and improves traffic mobility. There is a lot of research done in the field of traffic information predictions such as speed, flow and travel time. The most important research was done in the domain of cooperative intelligent transport system (C-ITS. The goal of this paper is to introduce the novel cooperation behaviour profile prediction through the example of flexible Road Trains useful road cooperation parameter, which contributes to the improvement of traffic mobility in Intelligent Transportation Systems. This paper presents an approach towards the control and cooperation behaviour modelling of vehicles in the flexible Road Train based on hybrid automaton and neuro-fuzzy (ANFIS prediction of cooperation profile of the flexible Road Train. Hybrid automaton takes into account complex dynamics of each vehicle as well as discrete cooperation approach. The ANFIS is a particular class of the ANN family with attractive estimation and learning potentials. In order to provide statistical analysis, RMSE (root mean square error, coefficient of determination (R2 and Pearson coefficient (r, were utilized. The study results suggest that ANFIS would be an efficient soft computing methodology, which could offer precise predictions of cooperative interactions between vehicles in Road Train, which is useful for prediction mobility in Intelligent Transport systems.
Directory of Open Access Journals (Sweden)
Hang Zhang
2014-02-01
Full Text Available The rapid development of numerical modeling techniques has led to more accurate results in modeling metal solidification processes. In this study, the cellular automaton-finite difference (CA-FD method was used to simulate the directional solidification (DS process of single crystal (SX superalloy blade samples. Experiments were carried out to validate the simulation results. Meanwhile, an intelligent model based on fuzzy control theory was built to optimize the complicate DS process. Several key parameters, such as mushy zone width and temperature difference at the cast-mold interface, were recognized as the input variables. The input variables were functioned with the multivariable fuzzy rule to get the output adjustment of withdrawal rate (v (a key technological parameter. The multivariable fuzzy rule was built, based on the structure feature of casting, such as the relationship between section area, and the delay time of the temperature change response by changing v, and the professional experience of the operator as well. Then, the fuzzy controlling model coupled with CA-FD method could be used to optimize v in real-time during the manufacturing process. The optimized process was proven to be more flexible and adaptive for a steady and stray-grain free DS process.
The simulation and analysis of small group effect in crowd evacuation
You, Lei; Hu, Jun; Gu, Musong; Fan, Wenjie; Zhang, Hong
2016-10-01
A crowd usually tends to move in small groups during evacuation. Small group has a large proportion in crowd evacuation, and small group effect affects crowd evacuation significantly. In this work, we propose a novel methodology for calculating movement profit based on cellular automaton model. Specifically, this methodology calculates the movement profit for a target at the next moment by comprehensively combining distance profit, density profit, and average velocity profit. In particular, this paper defines three types of small-group formation with totally six different forms of small group in terms of the size, and sets the corresponding movement velocity. At last, we simulate the evacuation process of small groups, and discuss the relationship among evacuation time, average movement velocity, and pedestrian density, and analyze the efficiency of small group evacuation in terms of evacuation strategies. As the simulation results demonstrated, the evacuation efficiency of different types of small groups is greatly different, and the same type of small groups with different forms is also different.
Kumar, Shailesh
2010-01-01
A cellular automata (CA) configuration is constructed that exhibits emergent failover. The configuration is based on standard Game of Life rules. Gliders and glider-guns form the core messaging structure in the configuration. The blinker is represented as the basic computational unit, and it is shown how it can be recreated in case of a failure. Stateless failover using primary-backup mechanism is demonstrated. The details of the CA components used in the configuration and its working are described, and a simulation of the complete configuration is also presented.
Modeling self-organizing traffic lights with elementary cellular automata
Gershenson, Carlos
2009-01-01
There have been several highway traffic models proposed based on cellular automata. The simplest one is elementary cellular automaton rule 184. We extend this model to city traffic with cellular automata coupled at intersections using only rules 184, 252, and 136. The simplicity of the model offers a clear understanding of the main properties of city traffic and its phase transitions. We use the proposed model to compare two methods for coordinating traffic lights: a green-wave method that tries to optimize phases according to expected flows and a self-organizing method that adapts to the current traffic conditions. The self-organizing method delivers considerable improvements over the green-wave method. For low densities, the self-organizing method promotes the formation and coordination of platoons that flow freely in four directions, i.e. with a maximum velocity and no stops. For medium densities, the method allows a constant usage of the intersections, exploiting their maximum flux capacity. For high dens...
Ngada, N M
2015-01-01
The complexity and cost of building and running high-power electrical systems make the use of simulations unavoidable. The simulations available today provide great understanding about how systems really operate. This paper helps the reader to gain an insight into simulation in the field of power converters for particle accelerators. Starting with the definition and basic principles of simulation, two simulation types, as well as their leading tools, are presented: analog and numerical simulations. Some practical applications of each simulation type are also considered. The final conclusion then summarizes the main important items to keep in mind before opting for a simulation tool or before performing a simulation.
Molecular dynamics simulation of ribosome jam
Matsumoto, Shigenori
2011-09-01
We propose a coarse-grained molecular dynamics model of ribosome molecules to study the dependence of translation process on environmental parameters. We found the model exhibits traffic jam property, which is consistent with an ASEP model. We estimated the influence of the temperature and concentration of molecules on the hopping probability used in the ASEP model. Our model can also treat environmental effects on the translation process that cannot be explained by such cellular automaton models. © 2010 Elsevier B.V. All rights reserved.
A Novel Seven Input Majority Gate in Quantum-dot Cellular Automata
Directory of Open Access Journals (Sweden)
Keivan Navi
2012-01-01
Full Text Available A Quantum Cellular Automaton (QCA is a nanotechnology which is an attractive alternative for transistor based technologies in the near future. A new seven input majority gate in quantum dot cellular automata is proposed in this paper. The basic elements in QCA are majority and inverter gates, therefore using a majority gate with more inputs in QCA circuit will cause reduction in cell count, latency and complexity. Furthermore, by using the proposed seven input majority gate we can design four inputs AND gate and OR gate in only two clock phases. By applying these kinds of gates QCA circuits could be simplified and optimized. In order to prove the functionality of the proposed device, QCADesigner tool and some physical proofs are utilized.
基于复合元胞自动机的分布式计算模型%A distributed computing model based on compound cellular automata
Institute of Scientific and Technical Information of China (English)
朱晓敏; 耿建东; 陈东华; 张润彤
2012-01-01
针对目前的分布式计算网络仍然缺乏较高的自治管理和自主认知能力,只能提供独立状态的服务,经常出现多点故障而造成分布式网络运作成本增加、延时加剧甚至网络崩溃等问题,将元胞自动机的相关概念及模型引入到分布式网络计算中,通过修正元胞自动机的原有机制,提出了复合元胞自动机模型,并建立了基于复合元胞自动机的分布式计算模型来提高分布式网络中认知自主管理能力,从而降低分布式计算成本和提高工作效率.通过模拟程序和GridSim软件包验证和展示了复合元胞自动机应用于分布式计算领域的可行性及优越性.%The concept of cellular automation and its model were introduced into distributed computation to solve current distributed computing networks' problems of high operating cost, serious time delay, and even debacle due to the multi-point failure caused by lack of high self-management and self-awareness and only providing independent services. By amending the original cellular automaton mechanism, a compound cellular automata model was proposed, and the distributed computing model based on compound cellular automata was established to enhance distributed networks' efficiency and reduce the operating cost. The comprehensive simulations and comparisons via GridSim verified the feasibility and efficiency of the proposed compound cellular automata model in the field of distributed computing.
Hybrid Automaton Based Controller Design for Damage Mitigation of Islanded Power Systems
Lahiri, Sudipta
some of these limitations, we derive a hybrid automaton model of a power system as a Discrete Event System (DES) plant and controller. The DES plant consists of a switched continuous system with an interface. The system state space is categorized based on safety criteria and discrete control specifications are embedded as transition rules within the DES controller. The DES controller searches for feasible control policies that drive the system trajectories from unsafe states to safe states. We define metrics to quantify the performance of these policies, thus allowing the derivation of the most suitable policy for a set of design specifications and disturbance type. Applications in voltage control, frequency control and dynamic service restoration is presented on a benchmark power system with approximately forty continuous states and eighteen thousand discrete states. To enable the analysis, we build a computational framework based on efficient symbolic computation tools in Mathematica and numerical integration tools in Matlab / Simulink so that the methodology can be replicated for a wide variety of applications. The framework is quite general, and may be expanded to problems beyond power systems.
Institute of Scientific and Technical Information of China (English)
于群; 曹娜; 郭剑波
2011-01-01
将元胞自动机理论应用到电力系统大停电机理研究中,提出并建立了用元胞自动机来模拟电网故障演化的电网故障元胞自动机模型,定义了电网故障元胞自动机模型中元胞、元胞空间、规则和邻居等的构成方法。利用电网故障元胞自动机模型,仿真研究了电网故障的传播演化过程,并对电网故障的自组织临界性（SOC）进行了验证。%By applying the theory of cellular automata in the evolutionary mechanism of the power system blackout,a model for simulating power failure with cellular automata is presented.The model defines the composing method of cells,cellular space,rules,neighbors,etc.The spread and evolution of power failure is investigated using proposed model and the self-organized criticality（SOC） of the power grid failure is verified. This work is supported by State Administration of Work Safety Project（No.10-052） and State Grid Corporation of China.
Institute of Scientific and Technical Information of China (English)
张浩
2015-01-01
针对车辆自组织网络（VANET）中由于相邻车辆会造成信号失真导致节点的高度移动性影响传输可靠性的问题，提出一种基于学习自动机建立虚拟退避算法的VANET介质访问算法。首先，借助于计数器共享的虚拟退避算法为每个节点分配一个计数器；然后，利用学习自动机确定指定节点序列号的最佳值；最后，使用RTS／CTS机制来奖惩每个节点以实现VBA介质访问。使用NS-2和MOVE进行的仿真实验验证了所提算法的有效性及可靠性，仿真结果表明，所提算法不仅改善了介质访问性能，而且节能效果明显，执行效果明显优于DCF和VBA等传统方案。%Adjacent vehicles will cause signal distortion in vehicular ad hoc networks (VANETs),which results in the transmission reliability being impacted by high mobility of nodes.Aiming at this problem,we propose a VANET medium access algorithm,it is based on setting up the virtual backoff algorithm (VBA)with learning automaton.First,the VBA by means of counter sharing allocates for every node a counter each.Then,it makes use of learning automaton to determine the optimum value of the specified node’s series number.Finally,it uses RTS/CTS mechanism to reward or punish each node to realise the medium access of VBA.The effectiveness and reliability of the proposed algorithm are verified by simulation experiment using NS-2 and MOVE.Simulation results show that the proposed algorithm improves the performance of medium access,and the energy saving effect is evident as well,its implementation effect is clearly better than traditional schemes of DCF and VBA.
Directory of Open Access Journals (Sweden)
Si-feng Gao
2015-03-01
Full Text Available The mechanism of stray grain formation at the platform of turbine blade simulator and the effect of withdrawal rate (V on the stray grain phenomenon have been investigated using a macro-scale ProCAST coupled with a 3D Cellular Automaton Finite Element (CAFE model. The results indicate that the stray grains nucleate at the edges of platform at V =150 μm·s-1 and 200 μm·s-1. Using ProCAST computer simulation software, it was proven that the stray grain formation is significantly dependent on the undercooling and the temperature field distribution in the platform. The macroscopic curvature of the liquidus isotherm becomes markedly concave with an increase in the withdrawal rate. The probability of stray grain formation at the edges of platform can be increased by increasing the withdrawal rate in the range of 70 μm·s-1 to 200 μm·s-1.
Pal, Prem; Gosalvez, Miguel A.; Sato, Kazuo; Hida, H.; Xing, Yan
2014-12-01
We combine experiment, theory and simulation to design and fabricate 3D structures with protected edges and corners on Si{1 1 0} using anisotropic wet chemical etching in 25 wt% tetramethylammonium hydroxide (TMAH) at 71 °C. In order to protect the convex corners formed by and directions, two methods are considered, namely, corner compensation and two-step etching. The mask design methodology for corner compensation is explained for various microstructures whose edges are aligned along different directions. The detailed geometry of each compensation pattern is shown to depend on the desired etch depth. The two-step wet etching process is explored in order to realize improved sharp convex corners. Using the same etchant concentration and temperature, the second etching is carried out after mask inversion from silicon nitride (Si3N4) to silicon dioxide (SiO2), obtained by local oxidation of silicon (LOCOS) followed by nitride etching. Based on the use of the continuous cellular automaton (CCA), the simulation results for both corner undercutting and two-step etching show that the CCA is suitable for the analysis and prediction of anisotropic etching on Si{1 1 0} wafers.
Study of strength properties of ceramic composites with soft filler based on 3D computer simulation
Smolin, Alexey Yu.; Smolin, Igor Yu.; Smolina, Irina Yu.
2016-11-01
The movable cellular automaton method which is a computational method of particle mechanics is applied to simulating uniaxial compression of 3D specimens of a ceramic composite. Soft inclusions were considered explicitly by changing the sort (properties) of automata selected randomly from the original fcc packing. The distribution of inclusions in space, their size, and the total fraction were varied. For each value of inclusion fraction, there were generated several representative specimens with individual pore position in space. The resulting magnitudes of the elastic modulus and strength of the specimens were scattered and well described by the Weibull distribution. We showed that to reveal the dependence of the elastic and strength properties of the composite on the inclusion fraction it is much better to consider the mathematical expectation of the corresponding Weibull distribution, rather than the average of the values for the specimens of the same inclusion fraction. It is shown that the relation between the mechanical properties of material and its inclusion fraction depends significantly on the material structure. Namely, percolation transition from isolated inclusions to interconnected clusters of inclusions strongly manifests itself in the dependence of strength on the fraction of inclusions. Thus, the curve of strength versus inclusion fraction fits different equations for a different kind of structure.
Quantum cellular automata and free quantum field theory
D'Ariano, Giacomo Mauro; Perinotti, Paolo
2017-02-01
In a series of recent papers [1-4] it has been shown how free quantum field theory can be derived without using mechanical primitives (including space-time, special relativity, quantization rules, etc.), but only considering the easiest quantum algorithm encompassing a countable set of quantum systems whose network of interactions satisfies the simple principles of unitarity, homogeneity, locality, and isotropy. This has opened the route to extending the axiomatic information-theoretic derivation of the quantum theory of abstract systems [5, 6] to include quantum field theory. The inherent discrete nature of the informational axiomatization leads to an extension of quantum field theory to a quantum cellular automata theory, where the usual field theory is recovered in a regime where the discrete structure of the automata cannot be probed. A simple heuristic argument sets the scale of discreteness to the Planck scale, and the customary physical regime where discreteness is not visible is the relativistic one of small wavevectors. In this paper we provide a thorough derivation from principles that in the most general case the graph of the quantum cellular automaton is the Cayley graph of a finitely presented group, and showing how for the case corresponding to Euclidean emergent space (where the group resorts to an Abelian one) the automata leads to Weyl, Dirac and Maxwell field dynamics in the relativistic limit. We conclude with some perspectives towards the more general scenario of non-linear automata for interacting quantum field theory.
Energy Technology Data Exchange (ETDEWEB)
Rojas C, E. L.; Avila, O., E-mail: leticia.rojas@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)
2012-10-15
In this work the simulation codes Monte Carlo, Penelope and MCNPX were used to calculate the doses by unit of accumulated activity S(N-N) in water spherical cells models of different radius exposed to mono-energetics electrons coming from punctual sources located in the center of the cellular nucleus. The studied cellular radii were: r{sub n}1=3 r{sub c}1=6; r{sub n}2=5 and r{sub c}2=10; r{sub n}3=9 and r{sub c}3=10 {mu}m; being r{sub n} and r{sub c} the nuclear and cellular radius, respectively. The following initial energies of the electrons were considered: 1, 5, 10, 50, 100, 500, 700 and 1000 keV. Additionally values S(N-N) were calculated for spherical cells of r= 3 {mu}m r{sub c}= 6 {mu}m due to the electrons coming from sources of {sup 111}In, {sup 177}Lu, {sup 99m}Tc, {sup 188}Re and {sup 186}Re. The obtained values are compared with those calculated by the MIRD Committee internationally accepted. The percentage differences between the values reported by this Committee and those calculated by Monte Carlo simulation are inside the interval that is considered valid for this dosimetry type. A major concordance was found among the values calculated by Monte Carlo simulation that among those calculated by MIRD and those obtained by simulation. Considering validated the use of both codes for similar applications, the values S(N-N) and S(N-C y) were obtained of prostate cancer real cells models of the PC3 line. The results were compared among them. The values of S(N-N) obtained with Penelope for the PC3 cells for the electron emissions of {sup 111}In, {sup 177}Lu, {sup 99m}Tc, {sup 188}Re and {sup 186}Re are: 3.19e{sup {sub {sup 4}}}, 3.24e{sup -4}, 1.37e{sup -4}, 1.11e{sup -4} and 1.91e{sup -4} Gy/Bq-s, respectively. Also the obtained results for S(N-C y) are: 2.95e{sup -6}, 3.17e{sup -5}, 2.09e{sup -6}, 1.41e{sup -5}, 1.86e{sup -5} Gy/Bq-s. (Author)
Ander, M; Beltrao, P; Di Ventura, B; Ferkinghoff-Borg, J; Foglierini, M; Kaplan, A; Lemerle, C; Tomás-Oliveira, I; Serrano, L
2004-06-01
SmartCell has been developed to be a general framework for modelling and simulation of diffusion-reaction networks in a whole-cell context. It supports localisation and diffusion by using a mesoscopic stochastic reaction model. The SmartCell package can handle any cell geometry, considers different cell compartments, allows localisation of species, supports DNA transcription and translation, membrane diffusion and multistep reactions, as well as cell growth. Moreover, different temporal and spatial constraints can be applied to the model. A GUI interface that facilitates model making is also available. In this work we discuss limitations and advantages arising from the approach used in SmartCell and determine the impact of localisation on the behaviour of simple well-defined networks, previously analysed with differential equations. Our results show that this factor might play an important role in the response of networks and cannot be neglected in cell simulations.
Aminova, G G; Sapinj, M R; Yerofeyeva, L M
2015-01-01
The cellular composition of the lamina propria of the mucous membrane of the jejunum was examined in the villi (LPV) and between the crypts (LPC). Two groups of male C57/BL6 mice aged 4-5 months were studied. Experimental group of animals (n=8) for 30 days was living under the terrestrial conditions in "BIOS-SLA" blocks and received a paste-like food made with standard feed containing water and casein. The control group of animals (n=6) were kept in standard vivarium conditions and received standard dry pellets. Studies have shown no significant changes in the content of lymphocytes in LPV and LPC in a terrestrial experiment. LPV was characterized by a sharp reduction in the number of plasma cells. In both LPV and LPC the number of eosinophils was increased, while the content of low differentiated forms of cells (blasts and large lymphocytes) was decreased. It is suggested that the changes in the contents of different cell types in ground-based experiment were due not only to the limited mobility of the animals but also to different composition of the feed.
A Proliferation of Air Pollution Simulation System base on Cellular Automata%基于元胞自动机的污染气体扩散模拟系统
Institute of Scientific and Technical Information of China (English)
秦弋丰; 杨雨诚; 谢育武; 李俚; 吴皆强
2015-01-01
元胞自动机模型( Cellular Automation Model, CA模型)是一种用于模拟离散动力系统内部的各独立单元间因为强烈非线性作用而引发的系统自组织演化过程的建模方式,规则的局部性和时空离散化是CA模型的主要特征.本系统基于当今城市最为严重的空气污染问题展开研究,主要通过在地图上确定污染源位置,并录入污染源数据,通过元胞自动机原理,模拟在有风和无风状态下污染气体元胞的运动状况,从微观到宏观,系统地描述污染气体的运动状况.%Cellular Automation Model(CA) is a modeling method used to simulate the internal unit between discrete dynamic system that caused the evolution of a self-organization in system because of nonlinear function. Temporal discretization and local rule is it main feature. We developed this system according to the one of the most serious problems of our city in these days which is air pollution. By pain point the source of pollution on the map and input the pollution data, through the principle of the Cellular automata, stimulated the movement of pollution gas cell under condition of both windy calm. Describe the motion of the pollution gas from micro to macro.
Cellular Cell Bifurcation of Cylindrical Detonations
Institute of Scientific and Technical Information of China (English)
HAN Gui-Lai; JIANG Zong-Lin; WANG Chun; ZHANG Fan
2008-01-01
Cellular cell pattern evolution of cylindrically-diverging detonations is numerically simulated successfully by solving two-dimensional Euler equations implemented with an improved two-step chemical kinetic model. From the simulation, three cell bifurcation modes are observed during the evolution and referred to as concave front focusing, kinked and wrinkled wave front instability, and self-merging of cellular cells. Numerical research demonstrates that the wave front expansion resulted from detonation front diverging plays a major role in the cellular cell bifurcation, which can disturb the nonlinearly self-sustained mechanism of detonations and finally lead to cell bifurcations.
Jin, Cheng-Jie; Jiang, Rui
2017-02-01
The pedestrian flow dynamics are very complex. Even the fundamental diagrams of uni-directional pedestrian flow exhibit diversity. In the empirical data of Mori-Tsukaguchi and Helbing et al, the flows drop drastically with medium densities and nearly keep constant with high densities, which is different from many other empirical and experimental results. To simulate these special phenomena with cellular automaton (CA) models, we use the new configuration, in which the occupied area of each pedestrian is 0.4 m * 0.2 m. The modeling framework is based on the ITP model, which is a two-process CA model presented in our previous paper, and one new rule is added: when the local density behind is below a threshold, pedestrians prefer to keep a certain front gap. With the simple rule, the new fundamental diagrams can qualitatively coincide with the empirical facts of Mori-Tsukaguchi and Helbing et al. Some other results, including simulation patterns and velocities of pedestrians can further confirm the validity of the new rule, and give some explanations for the diversity of different empirical data. These results are useful contributions for pedestrian flow modeling.
Obade, P.; Koedam, N.; Soetaert, K.E.R.; Neukermans, G.; Bogaert, J.; Nyssen, E.; van Nedervelde, F.; Berger, U.; Dahdouh-Guebas, F.
2009-01-01
Mangrove forests are ecologically and economically important and frequently dominating protected coastal areas in the tropics and subtropics at suitable intertidal zones and are often subjected to disturbances that disrupt the structure of an ecosystem, that change resource availability and that cre
Institute of Scientific and Technical Information of China (English)
B. Kutlu; M. Civi
2006-01-01
@@ We study the order parameter probability distribution at the critical point for the three-dimensional spin-1/2 and spin-1 Ising models on the simple cubic lattice under periodic boundary conditions.
Simulation of Quantum Cellular Automatas Based on Quantum Genetic Algorithm%基于量子遗传算法的量子细胞自动机仿真方法
Institute of Scientific and Technical Information of China (English)
赵晓辉; 蔡理; 张鹏
2011-01-01
利用遗传算法对基于半经典模型的量子细胞自动机进行仿真时,通常会遇到多个极值,容易陷入局部最优.为将量子遗传算法用于量子细胞自动机仿真,对量子遗传算法进行改进,将二进制量子位改为多进制量子位,重新设计了量子旋转门的调整策略,并给出了具体实现步骤.通过对测试函数寻优和量子细胞自动机电路的仿真,结果表明,改进后的量子遗传算法平均误差低,不易陷入局部极值,收敛速度较快,适用于量子细胞自动机仿真.%Using genetic algorithm (GA), there are usually many extremes in the simulation of quantum cellular automatas (QCA) based on the semi-classical model and therefore it is apt to falling into local optimization. An improved quantum genetic algorithm (QGA) to displace original binary quantum bits with multistate quantum bits was proposed to use in the QCA simulation. The adjustment strategy of the quantum revolving gate was redesigned and the concrete steps to apply the improved method into the QCA simulation were also given. Through the test function optimization and QCA circuit simulation, the results show that the improved quantum genetic algorithm has many advantages, including a lower average error and a faster convergence speed, and is easy to get out local extremum. Thus the improved algorithm with more excellent performances is very suitable for the QCA simulation.
Experimental and Numerical Simulations of the Solidification Process in Continuous Casting of Slab
Directory of Open Access Journals (Sweden)
Liang Bai
2016-03-01
Full Text Available Thermal simulation equipment (TSE was recently developed to simulate the solidification process in the industrial continuous casting of slab. The grain growth, solid-liquid interface movement, and columnar-to-equiaxed transition (CET in the continuous casting process can be reproduced using this equipment. The current study is focused on the effects of different cooling rates and superheat conditions on the grain growth in the solidification process of chromium-saving ferritic stainless steel (B425. The temperature distribution and microstructure evolution are simulated by a Cellular Automaton-Finite Element (CAFE model. The experimental results demonstrate that the temperature gradient and the grain growth rate of the sample can be effectively controlled by the equipment. It is observed from optical micrographs of the microstructure that the average equiaxed grain ratio increases when the superheat temperature decreases. The average equiaxed grain ratio is approximately 26% and 42% under superheat conditions of 40 °C and 30 °C, respectively, and no apparent columnar grain generation in the samples occurs under superheat conditions of 10 °C and 20 °C, as the result of a large thermal resistance at the copper-sample interface and low superheat inside the sample. A lower cooling rate results in a higher equiaxed crystal ratio in the sample. As the cooling rate decreases, the equiaxed crystal ratio becomes 14%, 23%, and 42%. Comparing the simulation results with the experimental observations, a reasonable qualitative agreement is achieved for the chilled layer thickness, grain morphology, and CET in the sample. Thus, the CAFE model in the current study can accurately predict the grain growth under different superheating and cooling rate conditions.
Stochastic Nature in Cellular Processes
Institute of Scientific and Technical Information of China (English)
刘波; 刘圣君; 王祺; 晏世伟; 耿轶钊; SAKATA Fumihiko; GAO Xing-Fa
2011-01-01
The importance of stochasticity in cellular processes is increasingly recognized in both theoretical and experimental studies. General features of stochasticity in gene regulation and expression are briefly reviewed in this article, which include the main experimental phenomena, classification, quantization and regulation of noises. The correlation and transmission of noise in cascade networks are analyzed further and the stochastic simulation methods that can capture effects of intrinsic and extrinsic noise are described.
Two-material optimization of plate armour for blast mitigation using hybrid cellular automata
Goetz, J.; Tan, H.; Renaud, J.; Tovar, A.
2012-08-01
With the increased use of improvised explosive devices in regions at war, the threat to military and civilian life has risen. Cabin penetration and gross acceleration are the primary threats in an explosive event. Cabin penetration crushes occupants, damaging the lower body. Acceleration causes death at high magnitudes. This investigation develops a process of designing armour that simultaneously mitigates cabin penetration and acceleration. The hybrid cellular automaton (HCA) method of topology optimization has proven efficient and robust in problems involving large, plastic deformations such as crash impact. Here HCA is extended to the design of armour under blast loading. The ability to distribute two metallic phases, as opposed to one material and void, is also added. The blast wave energy transforms on impact into internal energy (IE) inside the solid medium. Maximum attenuation occurs with maximized IE. The resulting structures show HCA's potential for designing blast mitigating armour structures.
Stylized Facts Generated Through Cellular Automata Models. Case of Study: The Game of Life
Coronel-Brizio, H F; Rodriguez-Achach, M E; Stevens-Ramirez, G A
2007-01-01
In the present work, a geometrical method to generate a two dimensional random walk by means of a bidimensional Cellular Automaton is presented. We illustrate it by means of Conway's Game of Life with periodical borders, with a large lattice of 3000 x 3000 cells. The obtained random walk is of character anomalous, and its projection to a one dimensional random walk is analyzed, showing that it presents some statistical properties similar to the so-called stylized facts observed in financial time series. We consider that the procedure presented here is important not only because of its simplicity, but also because it could help us to understand and shed light on the stylized facts formation mechanism.
Bosch, H.G.P.; Samuel, L.G.; Mullender, S.J.; Polakos, P.; Rittenhouse, G.
2007-01-01
Traditionally, cellular systems have been built in a hierarchical manner: many specialized cellular access network elements that collectively form a hierarchical cellular system. When 2G and later 3G systems were designed there was a good reason to make system hierarchical: from a cost-perspective i
DEFF Research Database (Denmark)
Gould, Derek A; Chalmers, Nicholas; Johnson, Sheena J;
2012-01-01
Recognition of the many limitations of traditional apprenticeship training is driving new approaches to learning medical procedural skills. Among simulation technologies and methods available today, computer-based systems are topical and bring the benefits of automated, repeatable, and reliable...... performance assessments. Human factors research is central to simulator model development that is relevant to real-world imaging-guided interventional tasks and to the credentialing programs in which it would be used....
Wituszynska, Weronika; Slesak, Ireneusz; Vanderauwera, Sandy; Szechynska-Hebda, Magdalena; Kornas, Andrzej; Van Der Kelen, Katrien; Mühlenbock, Per; Karpinska, Barbara; Mackowski, Sebastian; Van Breusegem, Frank; Karpinski, Stanislaw
2013-04-01
There is growing evidence that for a comprehensive insight into the function of plant genes, it is crucial to assess their functionalities under a wide range of conditions. In this study, we examined the role of lesion simulating disease1 (LSD1), enhanced disease susceptibility1 (EDS1), and phytoalexin deficient4 (PAD4) in the regulation of photosynthesis, water use efficiency, reactive oxygen species/hormonal homeostasis, and seed yield in Arabidopsis (Arabidopsis thaliana) grown in the laboratory and in the field. We demonstrate that the LSD1 null mutant (lsd1), which is known to exhibit a runaway cell death in nonpermissive conditions, proves to be more tolerant to combined drought and high-light stress than the wild type. Moreover, depending on growing conditions, it shows variations in water use efficiency, salicylic acid and hydrogen peroxide concentrations, photosystem II maximum efficiency, and transcription profiles. However, despite these changes, lsd1 demonstrates similar seed yield under all tested conditions. All of these traits depend on EDS1 and PAD4. The differences in the pathways prevailing in the lsd1 in various growing environments are manifested by the significantly smaller number of transcripts deregulated in the field compared with the laboratory, with only 43 commonly regulated genes. Our data indicate that LSD1, EDS1, and PAD4 participate in the regulation of various molecular and physiological processes that influence Arabidopsis fitness. On the basis of these results, we emphasize that the function of such important regulators as LSD1, EDS1, and PAD4 should be studied not only under stable laboratory conditions, but also in the environment abounding in multiple stresses.
Ross, Sheldon
2006-01-01
Ross's Simulation, Fourth Edition introduces aspiring and practicing actuaries, engineers, computer scientists and others to the practical aspects of constructing computerized simulation studies to analyze and interpret real phenomena. Readers learn to apply results of these analyses to problems in a wide variety of fields to obtain effective, accurate solutions and make predictions about future outcomes. This text explains how a computer can be used to generate random numbers, and how to use these random numbers to generate the behavior of a stochastic model over time. It presents the statist
Institute of Scientific and Technical Information of China (English)
陈晨; 陈建桥
2011-01-01
According to the theory of cellular automata ( CA), the urban traffic flows at 4 intersections were investigated and a set of discrete equations were proposed to describe the traffic dynamics. The effect of two signal control strategies, i.e., synchronous timing control and actuated control, on traffic flow were discussed. Simulation results show that ( 1 ) the effect of signal control strategies is related to the density of traffic flow; (2) and there exists a certain range of actuated control parameters in which the efficiency of traffic flow can be optimized. Therefore, in order to ensure the efficiency of traffic flow, one the proper signal control strategy should be chosen for different global densities of traffic flow.%采用细胞自动机方法(Cellular Automata:CA)模拟含4个路口的城市道路交通流状态,并通过离散方程描述车辆的运动过程.研究了信号灯控制策略(同步定时控制及感应控制)对交通流状态的影响.数值模拟结果表明,信号灯对交通流的影响与道路中车辆密度有关,同时,感应控制参数的选取存在一合理的取值范围,可优化交通流通行效率.因此,为保证交通流的通行效率,应针对不同的车辆密度,选取适当的信号灯控制方式.
Institute of Scientific and Technical Information of China (English)
寇勇刚; 吴桐水; 朱金福
2011-01-01
In order to research the role of airlines service innovation in the competition of the aviation market, the competition model of aviation service innovation is built up with cellular automata. Taken one of Shenzhen Airlinees' Shenzhen to Beijing flight in 2008 as an example, satisfied result have acquired by repeated experiments of simulation to the innovational cabin service evolution during the competition. The research conclusion shows that there are three factors which include the initial data of cellular automata,the service fitness and the sales promotion,all of the three effect the evolutional mutation period and make it into positive trend. Meanwhile, the role of the three factors become decreasing while the parameter of them gradually increasing.%为研究航空公司服务创新在市场竞争中的作用,基于元胞自动机设计了航空服务创新竞争模型.以深航2008年在深圳-北京航线上推出服务创新为例,经过重复试验较好地模拟了在该航线上进行服务创新取得成功的竞争演化过程.研究结果表明:初始接受服务创新的元胞数量、服务匹配度和品牌宣传效应度三个影响因素都对演化的突变周期起正向影响作用,且三个因素对突变周期的正向作用随着取值的增大而逐渐减弱.
The Universe as a Cellular System
Aragón-Calvo, Miguel A
2014-01-01
Cellular systems are observed everywhere in nature, from crystal domains in metals, soap froth and cucumber cells to the network of cosmological voids. Surprisingly, despite their disparate scale and origin all cellular systems follow certain scaling laws relating their geometry, topology and dynamics. Using a cosmological N-body simulation we found that the Cosmic Web, the largest known cellular system, follows the same scaling relations seen elsewhere in nature. Our results extend the validity of scaling relations in cellular systems by over 30 orders of magnitude in scale with respect to previous studies. The dynamics of cellular systems can be used to interpret local observations such as the local velocity anomaly as the result of a collapsing void in our cosmic backyard. Moreover, scaling relations depend on the curvature of space, providing an independent measure of geometry.
Optimal Band Allocation for Cognitive Cellular Networks
Liu, Tingting
2011-01-01
FCC new regulation for cognitive use of the TV white space spectrum provides a new means for improving traditional cellular network performance. But it also introduces a number of technical challenges. This letter studies one of the challenges, that is, given the significant differences in the propagation property and the transmit power limitations between the cellular band and the TV white space, how to jointly utilize both bands such that the benefit from the TV white space for improving cellular network performance is maximized. Both analytical and simulation results are provided.
Institute of Scientific and Technical Information of China (English)
覃松; 邓敏艺; 孔令江
2011-01-01
In order to study the influences of margin financing, as well as how to relieve the impact of short selling system,modeling theory and method using cellular automata are applied to establish a single stock automata model. In this paper,simulations of trading volume and price fluctuation before and after the introduction of margin financing business are carried out. Simulation results show that the release of new margin financing can increase trading volume and stabalize trading price more easily,and it may help to increase the fluctuation of the trading price. The advices about relieving the impact of short selling system are helpful to financial supervision departments in maintaining market stability.%为研究融资融券推出对股票市场带来的影响以及如何减少融券卖空对市场的冲击,建立基于元胞自动机的股票市场模型,对融资融券推出前后的股票交易量和价格波动进行计算机仿真.仿真结果表明,融资融券的推出既可能增加股票市场的交易量,有利于市场内在价格稳定机制形成,也可能对价格助涨助跌,增大市场的波动.本文还针对融券卖空的潜在风险提出规避建议,这对相关金融部门保障市场稳定运行具有一定借鉴意义.
Energy Technology Data Exchange (ETDEWEB)
Roentzsch, L.
2007-07-01
Single-crystalline nanostructures often exhibit gradients of surface (and/or interface) curvature that emerge from fabrication and growth processes or from thermal fluctuations. Thus, the system-inherent capillary force can initiate morphological transformations during further processing steps or during operation at elevated temperature. Therefore and because of the ongoing miniaturization of functional structures which causes a general rise in surface-to-volume ratios, solid-state capillary phenomena will become increasingly important: On the one hand diffusion-mediated capillary processes can be of practical use in view of non-conventional nanostructure fabrication methods based on self-organization mechanisms, on the other hand they can destroy the integrity of nanostructures which can go along with the failure of functionality. Additionally, capillarity-induced shape transformations are effected and can thereby be controlled by applied fields and forces (guided or driven evolution). With these prospects and challenges at hand, formation and shape transformation of single-crystalline nanostructures due to the system-inherent capillary force in combination with external fields or forces are investigated in the frame of this dissertation by means of atomistic computer simulations. For the exploration (search, description, and prediction) of reaction pathways of nanostructure shape transformations, kinetic Monte Carlo (KMC) simulations are the method of choice. Since the employed KMC code is founded on a cellular automaton principle, the spatio-temporal development of lattice-based N-particle systems (N up to several million) can be followed for time spans of several orders of magnitude, while considering local phenomena due to atomic-scale effects like diffusion, nucleation, dissociation, or ballistic displacements. In this work, the main emphasis is put on nanostructures which have a cylindrical geometry, for example, nanowires (NWs), nanorods, nanotubes etc
Energy Technology Data Exchange (ETDEWEB)
Ahmad, S. [University of Kashmir, Srinagar (India); Bhaduri, P.P. [Variable Energy Cyclotron Centre, Kolkata (India); Jahan, H. [Aligarh Muslim University, Aligarh (India); Senger, A. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Adak, R.; Samanta, S. [Bose Institute, Kolkata (India); Prakash, A. [Banaras Hindu University, Varanasi (India); Dey, K. [Gauhati University, Guwahati (India); Lebedev, A. [Institute für Kernphysik, Goethe Universität Frankfurt, Frankfurt (Germany); Kryshen, E. [Petersburg Nuclear Physics Institute (PNPI) NRC Kurchatov Institute, Gatchina (Russian Federation); Chattopadhyay, S., E-mail: sub@vecc.gov.in [Variable Energy Cyclotron Centre, Kolkata (India); Senger, P. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Bhattacharjee, B. [Gauhati University, Guwahati (India); Ghosh, S.K.; Raha, S. [Bose Institute, Kolkata (India); Irfan, M.; Ahmad, N. [Aligarh Muslim University, Aligarh (India); Farooq, M. [University of Kashmir, Srinagar (India); Singh, B. [Banaras Hindu University, Varanasi (India)
2015-03-01
A muon detection system (MUCH) based on a novel concept using a segmented and instrumented absorber has been designed for high-energy heavy-ion collision experiments. The system consists of 6 hadron absorber blocks and 6 tracking detector triplets. Behind each absorber block a detector triplet is located which measures the tracks of charged particles traversing the absorber. The performance of such a system has been simulated for the CBM experiment at FAIR (Germany) that is scheduled to start taking data in heavy ion collisions in the beam energy range of 6–45 A GeV from 2019. The muon detection system is mounted downstream to a Silicon Tracking System (STS) that is located in a large aperture dipole magnet which provides momentum information of the charged particle tracks. The reconstructed tracks from the STS are to be matched to the hits measured by the muon detector triplets behind the absorber segments. This method allows the identification of muon tracks over a broad range of momenta including tracks of soft muons which do not pass through all the absorber layers. Pairs of oppositely charged muons identified by MUCH could therefore be combined to measure the invariant masses in a wide range starting from low mass vector mesons (LMVM) up to charmonia. The properties of the absorber (material, thickness, position) and of the tracking chambers (granularity, geometry) have been varied in simulations of heavy-ion collision events generated with the UrQMD generator and propagated through the setup using the GEANT3, the particle transport code. The tracks are reconstructed by a Cellular Automaton algorithm followed by a Kalman Filter. The simulations demonstrate that low mass vector mesons and charmonia can be clearly identified in central Au+Au collisions at beam energies provided by the international Facility for Antiproton and Ion Research (FAIR)
Heterogeneous cellular networks
Hu, Rose Qingyang
2013-01-01
A timely publication providing coverage of radio resource management, mobility management and standardization in heterogeneous cellular networks The topic of heterogeneous cellular networks has gained momentum in industry and the research community, attracting the attention of standardization bodies such as 3GPP LTE and IEEE 802.16j, whose objectives are looking into increasing the capacity and coverage of the cellular networks. This book focuses on recent progresses, covering the related topics including scenarios of heterogeneous network deployment, interference management i
Nanostructured cellular networks.
Moriarty, P; Taylor, M D R; Brust, M
2002-12-01
Au nanocrystals spin-coated onto silicon from toluene form cellular networks. A quantitative statistical crystallography analysis shows that intercellular correlations drive the networks far from statistical equilibrium. Spin-coating from hexane does not produce cellular structure, yet a strong correlation is retained in the positions of nanocrystal aggregates. Mechanisms based on Marangoni convection alone cannot account for the variety of patterns observed, and we argue that spinodal decomposition plays an important role in foam formation.
Cellular automata modeling of pedestrian's crossing dynamics
Institute of Scientific and Technical Information of China (English)
张晋; 王慧; 李平
2004-01-01
Cellular automata modeling techniques and the characteristics of mixed traffic flow were used to derive the 2-dimensional model presented here for simulation of pedestrian's crossing dynamics.A conception of "stop point" is introduced to deal with traffic obstacles and resolve conflicts among pedestrians or between pedestrians and the other vehicles on the crosswalk.The model can be easily extended,is very efficient for simulation of pedestrian's crossing dynamics,can be integrated into traffic simulation software,and has been proved feasible by simulation experiments.
Cellular automata modelling of SEIRS
Institute of Scientific and Technical Information of China (English)
Liu Quan-Xing; Jin Zhen
2005-01-01
In this paper the SEIRS epidemic spread is analysed, and a two-dimensional probability cellular automata model for SEIRS is presented. Each cellular automation cell represents a part of the population that may be found in one of five states of individuals: susceptible, exposed (or latency), infected, immunized (or recovered) and death. Here studied are the effects of two cases on the epidemic spread. i.e. the effects of non-segregation and segregation on the latency and the infected of population. The conclusion is reached that the epidemic will persist in the case of non-segregation but it will decrease in the case of segregation. The proposed model can serve as a basis for the development of algorithms to simulate real epidemics based on real data. Last we find the density series of the exposed and the infected will fluctuate near a positive equilibrium point, when the constant for the immunized is less than its corresponding constant τ0. Our theoretical results are verified by numerical simulations.
Benchmark study between FIDAP and a cellular automata code
Akau, R. L.; Stockman, H. W.
A fluid flow benchmark exercise was conducted to compare results between a cellular automata code and FIDAP. Cellular automata codes are free from gridding constraints, and are generally used to model slow (Reynolds number approximately 1) flows around complex solid obstacles. However, the accuracy of cellular automata codes at higher Reynolds numbers, where inertial terms are significant, is not well-documented. In order to validate the cellular automata code, two fluids problems were investigated. For both problems, flow was assumed to be laminar, two-dimensional, isothermal, incompressible and periodic. Results showed that the cellular automata code simulated the overall behavior of the flow field.
城市交通拥堵的经济学分析和元胞自动机模拟%Economic Analysis of Urban Traffic Congestion and Cellular Automata Simulation
Institute of Scientific and Technical Information of China (English)
李捷; 朱明皓
2011-01-01
分析了城市道路系统的公共性和外部性.使用均衡分析的方法对城市交通拥堵进行了经济学分析,认为当城市道路的使用者超过一定数量时,道路交通的外部性凸显出来,由于这种外部性,道路交通系统总数处于过度使用的状态.最后使用元胞自动机对城市交通拥堵现象进行了模拟,发现为了改善城市交通堵塞,虽然需要增加交通供给,但是更为重要的是如何优化车流使得现有的交通供给得到充分的利用.%This paper discusses the economic characteristics of urban road traffic system, analyzes the public and external nature of the urban road system. Using the method of equilibrium analysis, the paper gives an economic analysis of urban traffic congestion and finds that the urban road traffic system shows externality when the number of road users reach a certain threshold. Because of this externality, the urban road traffic system is constantly in the state of excessive use. Finally, the article uses cellular automata to simulate the urban traffic congestion phenomenon and finds that, to improve urban traffic congestion, necessary as it is to increase the supply of urban road traffic system, what is more important is to figure out how to optimize traffic flow to make existing supply fully utilized.
Institute of Scientific and Technical Information of China (English)
刘天卓; 孙伟然; 杨靖
2011-01-01
在企业所面临的不同类型的危机中，产品质量危机所占的比重最大。本文从群体行为的角度研究企业产品质量危机的形成机理，利用元胞自动机的定性模拟理论和方法，建立消费者对产品的购买行为的演化模型，通过基于不同的从众系数和演化规则的演化，揭示群体从众行为与企业危机公关与企业产品质量危机的形成之间的关系，并在此基础上提出了基于消费者信任修复理论的管理思路，对现代企业的危机管理有一定的借鉴与指导意义。%In modem society, exigencies happen frequently, and if not handled properly in the incident, the influence that does not digest and relieve the crisis will result in formation. In the different types of crisis the corporation faced, the most proportion is product quality crisis. We research the formation mechanism of enterprise manufacture crisis from the point of group behaviour, utilize the theory and method of qualitative simulation of cellular automata, build the buying behaviour evolution model of customers, by the evolution based different conformity ratio and evolution rule, reveal the relationship between the group behaviour and business crisis public relation and enterprise production crisis, and based on that we propose management thread based on the consumer confidence restore model, which can guide the crisis management for companies.
Institute of Scientific and Technical Information of China (English)
冒玉婷; 邓建华
2015-01-01
An improved cellular automata model considering demand space is proposed to simulate bidirectional pedestrian flow based on NS model . New model incorporates a social distance to describe territorial effects between pedestrians and to avoid the conflicts in advance . In order to display the attraction between synthetic pedestrians , this model also considered the vision field that allows a pedestrian to collect information from cells in front of him/her and also to get the weighted demand parameter .Through Matlab simulation ,the velocity‐density diagram is obtained .Comparing the result with social model and Weidmann diagram ,we can see that new model can avoid the conflicts in advance effectively and the overall average speed has increased . Besides ,the presented model can reproduce Weidmann within the range of 0~5 p/m2 .%在NS模型的基础上提出考虑需求空间的双向行人交通流仿真模型。新模型采用需求空间来描述行人之间一定区域内的相互影响，提前避免冲突的发生。为更好地描述同向行人之间的吸引力，模型还考虑视野邻域以收集行人视野范围内的交通信息从而得到加权社会参数值。通过M atlab对改进的模型进行仿真，将仿真实验所得的流密图与Weidmann基本图和社会力模型比较，结果表明：新模型有效地提前避免冲突，行人流整体速度有所提高；行人密度在0～5 p／m2区间变化时能够再现Weidmann基本图。
Institute of Scientific and Technical Information of China (English)
马世发; 艾彬; 赵克飞
2014-01-01
Geography simulation model such as Cellular Automata (CA) is one of the most important tools for simulating and early warning the urban growth. The CA model can simulate urban sprawling accurately only when suitable conversion rules for every cell are achieved. Hence, the core of CA is to derive the conversion rules, and many researchers have been interested in discovering the rules. However, the conversion rules of tradi-tional CA are mainly derived from historic samples, in which both changed samples and unchanged ones are con-sidered for function fitting to retrieve parameters simultaneously. In this approach, it is assumed that if the urban sprawling occurred, samples were labeled as 1; otherwise, samples were accordingly labeled as 0. However, it will result in over fitting for the unchanged samples, because those samples with labels of 0 may have the potenti-ality to transform in future, especially for those located at the rural-urban fringe. Therefore, we proposed a gradi-ent CA for simulating urban sprawling. In this model, whether or not urban growth would occur was determined by the developing probability instead of its developed or undeveloped status. Accordingly, the unchanged sam-ples were set to the values ranging from 0 to 1. And in this research, the developing potentiality was estimated ac-cording to present planning maps. Compared with traditional CA, the gradient CA could avoid the over fitting problem for the unchanged samples to a certain degree. Moreover, the fitting objective was distinguished from traditional CA for its ability in retrieving conversion rules. In addition, particle swarm optimization algorithm was used to obtain the parameters of spatial indices. Finally, Guangzhou City, which locates in the Pearl River Delta of China, was chosen as the study area for model implementation and validation. In this case study, the spa-tial developing potentiality was allocated referring to the major function zone (MFZ) planning, because MFZ is
Energy Technology Data Exchange (ETDEWEB)
Cirioni, L.; Patau, J.P.; Nepveu, F. [Universite Paul Sabatier, 31 - Toulouse (France)
1998-04-01
A Monte Carlo code is developed to study the action of particles in Boron Neutron Capture Therapy (BNCT). Our aim is to calculate the probability of dissipating a lethal dose in cell nuclei. Cytoplasmic and nuclear membranes are considered as non-concentric ellipsoids. All geometrical parameters may be adjusted to fit actual configurations. The reactions {sup 10}B(n,{gamma} {alpha}){sup 7}Li and {sup 14}N(n,p) {sup 14}C create heavy ions which slow clown losing their energy. Their trajectories can be simulated taking into account path length straggling. The contribution of each reaction to the deposited dose in different cellular compartments can be studied and analysed for any distribution of {sup 10}B. (authors)
Caracciolo, Domenico; Fatichi, Simone; Istanbulluoglu, Erkan; Valerio Noto, Leonardo
2013-04-01
Predicting vegetation response in regions of ecotone transition under a changing climate is a among grand challenges in ecohydrology. In a small basin (1.3 sq km) in Sicily, Italy, where north-facing slopes are characterized by Quercus (tree), and south-facing slopes by Opuntia ficus-indaca (evergreen perennial species drought tolerant) and grasses we use an ecohydrological Cellular-Automaton model (CATGraSS) of vegetation coexistence driven by rainfall and solar radiation with downscaled future climate to examine the role of climate change on vegetation patterns. In the model, each cell can hold a single plant type or can be bare soil. Plant competition is modeled explicitly by keeping track of mortality and establishment of plants, both calculated probabilistically based on soil moisture stress. Topographic influence on incoming shortwave radiation is treated explicitly, which leads to spatial variations in potential evapotranspiration and resulting soil moisture and plant distribution. The influence of the soil thickness on the vegetation distribution is also introduced. The model is calibrated first using a representation of the current climate as a forcing and comparing the vegetation obtained from the model with the actual vegetation through statistical techniques.. The calibrated model is then forced with future climate scenarios generated using a stochastic downscaling technique based on the weather generator, AWE-GEN. This methodology allows for the downscaling of an ensemble of climate model outputs deriving the frequency distribution functions of factors of change for several statistics of temperature and precipitation from outputs of General Circulation Models. The stochastic downscaling is carried out using simulations of twelve General Circulation Models adopted in the IPCC 4AR, A1B emission scenario, for the future periods of 2046-2065 and 2081-2100. A high sensitivity of the vegetation distribution to variation of rainfall and temperature has been
Noto, L. V.; Caracciolo, D.; Fatichi, S.; Istanbulluoglu, E.
2013-12-01
Understanding and predicting vegetation change along ecosystem boundaries is among paramount challenges in ecohydrology. In this study, Cellular-Automaton Tree Grass Shrub Simulator (CATGraSS) is implemented in a small upland catchment in Sicily, IT, where north-facing slopes are characterized by quercus (trees), and south-facing slopes exhibit plant coexistence, composed of Opuntia ficus-indaca (shrub) and grasses, to examine the control of solar radiation on plant development and predict potential trajectories of vegetation change under the stress of global warming. CATGraSS is driven by stochastic rainfall and variable solar radiation on topography, represented by a fine-scale gridded domain where vegetation type at each cell is represented individually. In the model, each cell can hold a single plant type or remain empty. Plant competition is modeled explicitly by keeping track of mortality and establishment of plants, both calculated probabilistically based on soil moisture stress. Spatially explicit treatment of solar radiation, and a lower limit to soil moisture storage imposed by bedrock depth lead to spatial organization in evapotranspiration, soil moisture, runoff, and plant type. CATGraSS is first calibrated at the field site driven by stochastic climate that represent the current climate at the study site. Calibrated model results are examined against Google-Earth images. Implications of future climate change are examined using the advanced weather generator (AWE-GEN). AWE-GEN characterizes the statistical characteristics of selected climate variables and their change over time based on a multi-model ensemble of outputs from General Circulation Models (GCMs). Stochastic downscaling is carried out using simulations of twelve GCMs adopted in the IPCC 4AR, A1B emission scenario for the future scenarios 2046-2065 and 2081-2100. Future vegetation changed is predicted to bring a dramatic reorganization of the plant composition based mainly on the topography
Epigenetics and Cellular Metabolism
Xu, Wenyi; Wang, Fengzhong; Yu, Zhongsheng; Xin, Fengjiao
2016-01-01
Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well. PMID:27695375
Architected Cellular Materials
Schaedler, Tobias A.; Carter, William B.
2016-07-01
Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important applications, including lightweight structures, energy absorption, metamaterials, thermal management, and bioscaffolds.
Directory of Open Access Journals (Sweden)
Mittal R
2001-01-01
Full Text Available A 31-year-old man had asymptomatic, stationary, 1.5X2 cm, shiny, smooth, dark blue nodule on dorsum of right hand since 12-14 years. In addition he had developed extensive eruption of yellow to orange papulonodular lesions on extensors of limbs and buttocks since one and half months. Investigations confirmed that yellow papules were xanthomatosis and he had associated diabetes mellitus and hyperlipidaemia. Biopsy of blue nodule confirmed the clinical diagnosis of cellular blue naevus. Cellular blue naevus is rare and its association with xanthomatosis and diabetes mellitus were interesting features of above patients which is being reported for its rarity.
Cellular rehabilitation of photobiomodulation
Liu, Timon Cheng-Yi; Yuan, Jian-Qin; Wang, Yan-Fang; Xu, Xiao-Yang; Liu, Song-Hao
2007-05-01
Homeostasis is a term that refers to constancy in a system. A cell in homeostasis normally functions. There are two kinds of processes in the internal environment and external environment of a cell, the pathogenic processes (PP) which disrupts the old homeostasis (OH), and the sanogenetic processes (SP) which restores OH or establishes a new homeostasis (NH). Photobiomodualtion (PBM), the cell-specific effects of low intensity monochromatic light or low intensity laser irradiation (LIL) on biological systems, is a kind of modulation on PP or SP so that there is no PBM on a cell in homeostasis. There are two kinds of pathways mediating PBM, the membrane endogenetic chromophores mediating pathways which often act through reactive oxygen species, and membrane proteins mediating pathways which often enhance cellular SP so that it might be called cellular rehabilitation. The cellular rehabilitation of PBM will be discussed in this paper. It is concluded that PBM might modulate the disruption of cellular homeostasis induced by pathogenic factors such as toxin until OH has been restored or NH has been established, but can not change homeostatic processes from one to another one.
Cellular Response to Irradiation
Institute of Scientific and Technical Information of China (English)
LIU Bo; YAN Shi-Wei
2011-01-01
To explore the nonlinear activities of the cellular signaling system composed of one transcriptional arm and one protein-interaction arm, we use an irradiation-response module to study the dynamics of stochastic interactions.It is shown that the oscillatory behavior could be described in a unified way when the radiation-derived signal and noise are incorporated.
Institute of Scientific and Technical Information of China (English)
寇勇刚; 吴桐水; 柳青
2011-01-01
为研究民航运输产业的竞争演化,考虑航空公司的资源竞争力、职能竞争力、核心竞争力及动态核心能力四层次竞争力等因素,建立了元胞自动机模型.以中美两国民航运输产业的竞争演化为例,对主导元胞(航空公司)和支持元胞(机场)的协同发展及其盈利状况进行了模拟研究.研究结果表明,美国民航业放松航空管制后因航空公司动态核心能力不强,行业整体盈利状况不佳；我国民航业半放松管制后,盈利状况也不容乐观.然而,提高航空公司的动态核心能力既可以避免美国民航业发展中经营惨淡的局面,同时又能促进我国民航业的快速发展.%In order to research the competition evolution of the aviation industry, built the cellular automata model with consideration of resource, function, core competence and dynamic core competence of airlines four competition factors. Took competition evolution of the civil aviation industry in China and USA for examples, simulated the coordinated development and profit status of the major cells (airlines) and supportive cells (airports). The result indicates the industry profit status of USA are not good after the deregulation because airlines do not have enough dynamic core competence, the industry profit status of China also are not good after the half-deregulation. However, improving the dynamic core competence of airlines could prevent the civil aviation industry from the loss of USA development example, meanwhile, could promote rapidly development of our country's civil aviation industry, too.
Infinite Time Cellular Automata: A Real Computation Model
Givors, Fabien; Ollinger, Nicolas
2010-01-01
We define a new transfinite time model of computation, infinite time cellular automata. The model is shown to be as powerful than infinite time Turing machines, both on finite and infinite inputs; thus inheriting many of its properties. We then show how to simulate the canonical real computation model, BSS machines, with infinite time cellular automata in exactly \\omega steps.
Energy Technology Data Exchange (ETDEWEB)
Rojas C, E. L. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Santos C, C. L. [Universidad Autonoma del Estado de Mexico, Paseo Tollocan y Jesus Carranza, Toluca 50120, Estado de Mexico (Mexico)], e-mail: leticia.rojas@inin.gob.mx
2009-10-15
The {sup 188}Re is a radionuclide of radiation gamma emitter, useful in obtaining of gamma-graphic images, but it is also emitter of beta radiations and Auger electrons. A bio-molecule directed to a specific receptor of a cancer cell labeled with a emitter radionuclide of beta particles and Auger electrons, as the {sup 188}Re-Tat-Bombesin, it has the potential to be used in radiotherapy of molecular targets for its capacity to penetrate to cellular nucleus. In this system, the radiation dose is distributed in way located at microscopic levels in sub cellular specific places, where Auger emissions contributes of significant way in absorbed dose. The cellular dosimetry is realized in most of cases, using analytic or semi analytical methods, for example the cellular MIRD methodology. However, it is required to complement these calculations simulating the electrons transport and considering experimental bio kinetics data. Therefore, in this work preliminary results are presented of dosimetric calculation to sub cellular level for {sup 188}Re-Tat-Bombesin by Monte Carlo simulation, using the 2008 version of PENELOPE: PENEASY code. The spatial distribution of absorbed dose in membrane, cytoplasm and nucleus, was calculated with geometry of a cell of 10 {mu}m of diameter, a nucleus of 2 {mu}m of ratio and membrane of 0.2 {mu}m of thickness, considering elementary constitution for each cellular compartment proposal in literature. The total number of disintegrations at sub cellular level was evaluated integrating the activity in function of time starting from experimental bio kinetics data in mamma cancer cells MDA-MB231. The preliminary results show that 46.4% of total disintegrations for unit of captured activity by cell occurs in nucleus, 38.4% in membrane and 15.2% in cytoplasm. The due absorbed dose to Auger electrons for 1 Bq of {sup 188}Re located in cellular membrane were respectively of 1.32E-1 and 1.43E-1 Gy in cytoplasm and nucleus. (Author)
Alleviate Cellular Congestion Through Opportunistic Trough Filling
Directory of Open Access Journals (Sweden)
Yichuan Wang
2014-04-01
Full Text Available The demand for cellular data service has been skyrocketing since the debut of data-intensive smart phones and touchpads. However, not all data are created equal. Many popular applications on mobile devices, such as email synchronization and social network updates, are delay tolerant. In addition, cellular load varies significantly in both large and small time scales. To alleviate network congestion and improve network performance, we present a set of opportunistic trough filling schemes that leverage the time-variation of network congestion and delay-tolerance of certain traffic in this paper. We consider average delay, deadline, and clearance time as the performance metrics. Simulation results show promising performance improvement over the standard schemes. The work shed lights on addressing the pressing issue of cellular overload.
Molecular and Cellular Signaling
Beckerman, Martin
2005-01-01
A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...
Environment Aware Cellular Networks
Ghazzai, Hakim
2015-02-01
The unprecedented rise of mobile user demand over the years have led to an enormous growth of the energy consumption of wireless networks as well as the greenhouse gas emissions which are estimated currently to be around 70 million tons per year. This significant growth of energy consumption impels network companies to pay huge bills which represent around half of their operating expenditures. Therefore, many service providers, including mobile operators, are looking for new and modern green solutions to help reduce their expenses as well as the level of their CO2 emissions. Base stations are the most power greedy element in cellular networks: they drain around 80% of the total network energy consumption even during low traffic periods. Thus, there is a growing need to develop more energy-efficient techniques to enhance the green performance of future 4G/5G cellular networks. Due to the problem of traffic load fluctuations in cellular networks during different periods of the day and between different areas (shopping or business districts and residential areas), the base station sleeping strategy has been one of the main popular research topics in green communications. In this presentation, we present several practical green techniques that provide significant gains for mobile operators. Indeed, combined with the base station sleeping strategy, these techniques achieve not only a minimization of the fossil fuel consumption but also an enhancement of mobile operator profits. We start with an optimized cell planning method that considers varying spatial and temporal user densities. We then use the optimal transport theory in order to define the cell boundaries such that the network total transmit power is reduced. Afterwards, we exploit the features of the modern electrical grid, the smart grid, as a new tool of power management for cellular networks and we optimize the energy procurement from multiple energy retailers characterized by different prices and pollutant
Institute of Scientific and Technical Information of China (English)
李锰; 杨峰
2011-01-01
A 2-D cellular automata fault model with 81×81 cells was constructed to test its seismicity performance. In a series of tests 4 kinds of fault strength heterogeneity and 6 different strength geometrical distributions were taken. With the model simulation we analyzed how the fault structure heterogeneity affects macroscopic fault failure behavior and generated seismic sequence type. The results show that with increasing degree of heterogeneity the macroscopic deformation and fracture process present from brittle to plastic behavior, and produce 3 different types of seismic sequence, I.e. , main shock type, foreshock-main shock-aftershock type and swarm type. In the same time, with increasing fault strength heterogeneity the fracture size distribution more regularly follows the G-R relation. Besides, temporarily the events occur in a certain random process, that is, small events appear randomly, medium size events occur in clusters and large ones emerge quasi-periodically. The event clustering and quasi-periodic occurrences become less significant with the fault heterogeneity increasing. It is also found that the randomness of structural geometric variation may affect characteristics of seismic sequences, but the difference in randomness becomes weaker as degree of heterogeneity increases.%基于断层强度分布的非均匀性,构建了由81×81个细胞单元组成的4种不同匀质度及其各自6种不同随机构型共计24个非均匀二维单断层模型样本,并通过设计的细胞自动机模拟程序,在保持其它模拟参数不变的条件下对它们进行了模拟试验.研究结果表明,随着断层结构非匀质度的增加,其宏观变形破坏行为由相对脆性向塑性变化；地震序列类型依次表现出主震型、前震-主震-余震型和震群型；震级分布表现出非均匀性依次减小；地震发生在时间上表现为一种确定性的随机过程,即小震随机、中强地震丛集和大震准周期的特点.此
Mobile node localization in cellular networks
Malik, Yasir; Abdulrazak, Bessam; Tariq, Usman; 10.5121/ijwmn.2011.3607
2012-01-01
Location information is the major component in location based applications. This information is used in different safety and service oriented applications to provide users with services according to their Geolocation. There are many approaches to locate mobile nodes in indoor and outdoor environments. In this paper, we are interested in outdoor localization particularly in cellular networks of mobile nodes and presented a localization method based on cell and user location information. Our localization method is based on hello message delay (sending and receiving time) and coordinate information of Base Transceiver Station (BTSs). To validate our method across cellular network, we implemented and simulated our method in two scenarios i.e. maintaining database of base stations in centralize and distributed system. Simulation results show the effectiveness of our approach and its implementation applicability in telecommunication systems.
Mobile Node Localization in Cellular Networks
Directory of Open Access Journals (Sweden)
Yasir Malik
2012-01-01
Full Text Available Location information is the major component in location based applications. This information is used in different safety and service oriented applications to provide users with services according to their Geolocation. There are many approaches to locate mobile nodes in indoor and outdoor environments. In thispaper, we are interested in outdoor localization particularly in cellular networks of mobile nodes andpresented a localization method based on cell and user location information. Our localization method is based on hello message delay (sending and receiving time and coordinate information of Base Transceiver Station (BTSs. To validate our method across cellular network, we implemented and simulated our method in two scenarios i.e. maintaining database of base stations in centralize and distributed system. Simulation results show the effectiveness of our approach and its implementation applicability in telecommunication systems.
Power Control in Multi-Layer Cellular Networks
Davaslioglu, Kemal
2012-01-01
We investigate the possible performance gains of power control in multi-layer cellular systems where microcells and picocells are distributed within macrocells. Although multilayers in cellular networks help increase system capacity and coverage, and can reduce total energy consumption; they cause interference, reducing the performance of the network. Therefore, downlink transmit power levels of multi-layer hierarchical cellular networks need to be controlled in order to fully exploit their benefits. In this work, we present an analytical derivation to determine optimum power levels for two-layer cellular networks and generalize our solution to multi-layer cellular networks. We also simulate our results in a typical multi-layer network setup and observe significant power savings compared to single-layer cellular networks.
Wang, Weiling; Luo, Sen; Zhu, Miaoyong
2016-03-01
To improve the computational efficiency of the three-dimensional (3D) cellular-automaton-finite-volume-method (CA-FVM) model for describing the dendritic growth of alloy, the block-correction technique (BCT) and the parallel computation approach are introduced. Accordingly, a serial of investigations on the efficiency of the optimized codes in dealing with the designed cases for the melt flow and the heat transfer problems is carried out. Moreover, the accuracy of the present codes is evaluated by the comparisons between the solution to the melt flow and the heat transfer problems and the results from analytical equations and the commercial software. Additionally, the capability of the present CA model is evaluated by comparing the steady growth parameters of the equiaxed dendritic tip and the morphology and the secondary dendrite arm spacing (SDAS) of columnar dendrites with the LGK analytical model and the experimental results of the unidirectional solidification of high-carbon steels. The results show that with the introduction of the 3D BCT, the iteration process of the serial tri-diagonal matrix algorithm (TDMA) code changes from the fluctuation type to the smooth one, and thus, the computational cost is reduced significantly. Moreover, the parallel Jacobi code with one two-dimensional (2D) iteration in 3D BCT is proved to be the most efficient one among the codes compiled in the present work, and therefore, accordingly it is employed to simulate the 3D dendritic growth of alloys. The calculated velocity distribution and temperature variation agree well with the results from the analytical equations and the commercial software. The predicted steady tip velocities agree with the LGK analytical model as the undercooling is 6 K to 7 K. Moreover, the predicted columnar dendritic morphology and SDAS of high-carbon Fe-C alloys during the unidirectional solidification agree with the experimental results.
Barrio-Parra, Fernando; Rodríguez-Santalla, Inmaculada
2016-08-01
Coastal dunes are sedimentary environments characterized by their high dynamism. Their evolution is determined by sedimentary exchanges between the beach-dune subsystems and the dune dynamics itself. Knowledge about these exchanges is important to prioritize management and conservation strategies of these environments. The aim of this work is the inclusion of the aeolian transport rates obtained using a calibrated cellular automaton to estimate the beach-dune sediment exchange rates in a real active dune field at El Fangar Spit (Ebro Delta, Spain). The dune dynamics model is able to estimate average aeolian sediment fluxes. These are used in combination with the observed net sediment budget to obtain a quantitative characterization of the sediment exchange interactions. The methods produce a substantial improvement in the understanding of coastal sedimentary systems that could have major implications in areas where the management and conservation of dune fields are of concern.
Cellular communication through light.
Directory of Open Access Journals (Sweden)
Daniel Fels
Full Text Available Information transfer is a fundamental of life. A few studies have reported that cells use photons (from an endogenous source as information carriers. This study finds that cells can have an influence on other cells even when separated with a glass barrier, thereby disabling molecule diffusion through the cell-containing medium. As there is still very little known about the potential of photons for intercellular communication this study is designed to test for non-molecule-based triggering of two fundamental properties of life: cell division and energy uptake. The study was performed with a cellular organism, the ciliate Paramecium caudatum. Mutual exposure of cell populations occurred under conditions of darkness and separation with cuvettes (vials allowing photon but not molecule transfer. The cell populations were separated either with glass allowing photon transmission from 340 nm to longer waves, or quartz being transmittable from 150 nm, i.e. from UV-light to longer waves. Even through glass, the cells affected cell division and energy uptake in neighboring cell populations. Depending on the cuvette material and the number of cells involved, these effects were positive or negative. Also, while paired populations with lower growth rates grew uncorrelated, growth of the better growing populations was correlated. As there were significant differences when separating the populations with glass or quartz, it is suggested that the cell populations use two (or more frequencies for cellular information transfer, which influences at least energy uptake, cell division rate and growth correlation. Altogether the study strongly supports a cellular communication system, which is different from a molecule-receptor-based system and hints that photon-triggering is a fine tuning principle in cell chemistry.
Ollinger, Nicolas
2002-01-01
Jury : François Blanchard (Rapporteur), Marianne Delorme (Directeur), Jarkko Kari (Président), Jacques Mazoyer (Directeur), Dominique Perrin, Géraud Sénizergues (Rapporteur); Cellular automata provide a uniform framework to study an important problem of "complex systems" theory: how and why do system with a easily understandable -- local -- microscopic behavior can generate a more complicated -- global -- macroscopic behavior? Since its introduction in the 40s, a lot of work has been done to ...
Engineering Cellular Metabolism
DEFF Research Database (Denmark)
Nielsen, Jens; Keasling, Jay
2016-01-01
Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds...... of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation....
Institute of Scientific and Technical Information of China (English)
王冬; 苗宗成; 王向轲; 曹晖
2013-01-01
The polymer crystallization process and mechanism were studied by computer simulation method. It is benefit to understand the crystallization kinetics by comparing the simulated results with the experimental results. Based on a nonconserved spatiotemporal Ginzburg-Landau equation TDGL model, a novel three dimensional phase field model was established by combining the cellular automaton method with the general phase field model. For simulating the real three dimensional polymer crystallization process, the cellular automaton method was modified by the different steric structures and discretization methods. The different steric structures or discretization methods are related to the lattice parameters of syndiotactic polypropylene single crystals and the crystal growth faces of polymer single crystals. It was suggested that the novel method is a way of building bridges between the diffusion equation and polymer characterization. Moreover, the diffusion equations are discretized according to the diffusion coefficient of every lattice site in various crystal growth faces,and the shape of lattice is selected based on the real proportion of the unit cell dimensions. Especially, the other physics parameters of syndiotactic polypropylene also were introduced into the phase field model. The spatio-temporal growth of syndiotactic polypropylene single crystals during isothermal crystallization was simulated by the novel three dimensional phase field model. Three dimensional numerical calculations are performed to elucidate the faceted single crystal growth including square, rectangular, lozenge-shaped, and hexagonal single crystals. The corresponding three dimensional results were illustrated by the MatLab. Our simulated patterns are in good agreement with the experimental morphologies, and the physical origin of polymer single crystal growth is discussed.%利用元胞自动机方法与相场模型的结合建立新型三维模拟相场模型.同时,为模拟真实的、三
Pei Ping; YURY N. PETRENKO
2015-01-01
A Mesh network simulation framework which provides a powerful and concise modeling chain for a network structure will be introduce in this report. Mesh networks has a special topologic structure. The paper investigates a message transfer in wireless mesh network simulation and how does it works in cellular network simulation. Finally the experimental result gave us the information that mesh networks have different principle in transmission way with cellular networks in transmission, and multi...
Lattice gas hydrodynamics: Theory and simulations
Energy Technology Data Exchange (ETDEWEB)
Hasslacher, B.
1993-01-01
The first successful application of a microscopic analogy to create a skeleton cellular automaton and analyze it with statistical mechanical tools, was the work of Frisch, Hasslacher and Pomeau on the Navier-Stokes equation in two and three dimensions. This has become a very large research area with lattice gas models and methods being used for both fundamental investigations into the foundations of statistical mechanics and a large number of diverse applications. This present research was devoted to enlarging the fundamental scope of lattice gas models and proved quite successful. Since the beginning of this proposal, cellular automata have been constructed for statistical mechanical models, fluids, diffusion and shock systems in fundamental investigations. In applied areas, there are now excellent lattice gas models for complex flows through porous media, chemical reaction and combustion dynamics, multiphase flow systems, and fluid mixtures with natural boundaries. With extended cellular fluid models, one can do problems with arbitrary pairwise potentials. Recently, these have been applied to such problems as non-newtonian or polymeric liquids and a mixture of immiscible fluids passing through fractal or spongelike media in two and three dimensions. This proposal has contributed to and enlarged the scope of this work.
Synchronization, TIGoRS, and Information Flow in Complex Systems: Dispositional Cellular Automata.
Sulis, William H
2016-04-01
Synchronization has a long history in physics where it refers to the phase matching of two identical oscillators. This notion has been extensively studied in physics as well as in biology, where it has been applied to such widely varying phenomena as the flashing of fireflies and firing of neurons in the brain. Human behavior, however, may be recurrent but it is not oscillatory even though many physiological systems do exhibit oscillatory tendencies. Moreover, much of human behaviour is collaborative and cooperative, where the individual behaviours may be distinct yet contemporaneous (if not simultaneous) and taken collectively express some functionality. In the context of behaviour, the important aspect is the repeated co-occurrence in time of behaviours that facilitate the propagation of information or of functionality, regardless of whether or not these behaviours are similar or identical. An example of this weaker notion of synchronization is transient induced global response synchronization (TIGoRS). Previous work has shown that TIGoRS is a ubiquitous phenomenon among complex systems, enabling them to stably parse environmental transients into salient units to which they stably respond. This leads to the notion of Sulis machines, which emergently generate a primitive linguistic structure through their dynamics. This article reviews the notion of TIGoRS and its expression in several complex systems models including tempered neural networks, driven cellular automata and cocktail party automata. The emergent linguistics of Sulis machines are discussed. A new class of complex systems model, the dispositional cellular automaton is introduced. A new metric for TIGoRS, the excess synchronization, is introduced and applied to the study of TIGoRS in dispositional cellular automata. It is shown that these automata exhibit a nonlinear synchronization response to certain perturbing transients.
Xu, Xiang; Lin, Feng
2017-01-01
This book introduces new techniques for cellular image feature extraction, pattern recognition and classification. The authors use the antinuclear antibodies (ANAs) in patient serum as the subjects and the Indirect Immunofluorescence (IIF) technique as the imaging protocol to illustrate the applications of the described methods. Throughout the book, the authors provide evaluations for the proposed methods on two publicly available human epithelial (HEp-2) cell datasets: ICPR2012 dataset from the ICPR'12 HEp-2 cell classification contest and ICIP2013 training dataset from the ICIP'13 Competition on cells classification by fluorescent image analysis. First, the reading of imaging results is significantly influenced by one’s qualification and reading systems, causing high intra- and inter-laboratory variance. The authors present a low-order LP21 fiber mode for optical single cell manipulation and imaging staining patterns of HEp-2 cells. A focused four-lobed mode distribution is stable and effective in optical...
Bao, Yi; Chen, Ming
2011-01-01
Modern radio communication is faced with a problem about how to distribute restricted frequency to users in a certain space. Since our task is to minimize the number of repeaters, a natural idea is enlarging coverage area. However, coverage has restrictions. First, service area has to be divided economically as repeater's coverage is limited. In this paper, our fundamental method is to adopt seamless cellular network division. Second, underlying physics content in frequency distribution problem is interference between two close frequencies. Consequently, we choose a proper frequency width of 0.1MHz and a relevantly reliable setting to apply one frequency several times. We make a few general assumptions to simplify real situation. For instance, immobile users yield to homogenous distribution; repeaters can receive and transmit information in any given frequency in duplex operation; coverage is mainly decided by antenna height. Two models are built up to solve 1000 users and 10000 users situations respectively....
Engineering Cellular Metabolism.
Nielsen, Jens; Keasling, Jay D
2016-03-10
Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds, and pharmaceuticals. However, making cells into efficient factories is challenging because cells have evolved robust metabolic networks with hard-wired, tightly regulated lines of communication between molecular pathways that resist efforts to divert resources. Here, we will review the current status and challenges of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation.
Analysis of deterministic finite automaton in computability logic%确定有限自动机推理的可计算逻辑分析
Institute of Scientific and Technical Information of China (English)
闵兰; 刘益; 陈晓敏
2011-01-01
针对确定有限自动机对输入符号串的识别过程,提出了采用可计算逻辑来分析确定有限自动机的功能结构及其状态转换函数.在可计算逻辑中,计算问题是机器和环境博弈的过程.同样确定有限自动机对输入符号串的识别过程也可当作机器与用户的博弈,如果输入符号串满足确定有限自动机的语法规则能够识别出来,表示机器赢,否则用户赢.%For the identification process of character string in DFA(deterministic finite automaton), using computability logic theory to analyze the form of state function and the faction of DFA is put forward in this paper. According to the computability logic theory, computability question is a game between the machine and environment. Likewise the identification process of character string in DFA is regarded as a game between machine and user.
Traffic dynamics around weaving section influenced by accident: Cellular automata approach
Kong, Lin-Peng; Li, Xin-Gang; Lam, William H. K.
2015-07-01
The weaving section, as a typical bottleneck, is one source of vehicle conflicts and an accident-prone area. Traffic accident will block lanes and the road capacity will be reduced. Several models have been established to study the dynamics around traffic bottlenecks. However, little attention has been paid to study the complex traffic dynamics influenced by the combined effects of bottleneck and accident. This paper presents a cellular automaton model to characterize accident-induced traffic behavior around the weaving section. Some effective control measures are proposed and verified for traffic management under accident condition. The total flux as a function of inflow rates, the phase diagrams, the spatial-temporal diagrams, and the density and velocity profiles are presented to analyze the impact of accident. It was shown that the proposed control measures for weaving traffic can improve the capacity of weaving section under both normal and accident conditions; the accidents occurring on median lane in the weaving section are more inclined to cause traffic jam and reduce road capacity; the capacity of weaving section will be greatly reduced when the accident happens downstream the weaving section.
Conway's game of life is a near-critical metastable state in the multiverse of cellular automata
Reia, Sandro M.; Kinouchi, Osame
2014-05-01
Conway's cellular automaton Game of Life has been conjectured to be a critical (or quasicritical) dynamical system. This criticality is generally seen as a continuous order-disorder transition in cellular automata (CA) rule space. Life's mean-field return map predicts an absorbing vacuum phase (ρ =0) and an active phase density, with ρ =0.37, which contrasts with Life's absorbing states in a square lattice, which have a stationary density of ρ2D≈0.03. Here, we study and classify mean-field maps for 6144 outer-totalistic CA and compare them with the corresponding behavior found in the square lattice. We show that the single-site mean-field approach gives qualitative (and even quantitative) predictions for most of them. The transition region in rule space seems to correspond to a nonequilibrium discontinuous absorbing phase transition instead of a continuous order-disorder one. We claim that Life is a quasicritical nucleation process where vacuum phase domains invade the alive phase. Therefore, Life is not at the "border of chaos," but thrives on the "border of extinction."
Application of Digital Cellular Radio for Mobile Location Estimation
Directory of Open Access Journals (Sweden)
Farhat Anwar
2012-08-01
Full Text Available The capability to locate the position of mobiles is a prerequisite to implement a wide range of evolving ITS services. Radiolocation has the potential to serve a wide geographical area. This paper reports an investigation regarding the feasibility of utilizing cellular radio for the purpose of mobile location estimation. Basic strategies to be utilized for location estimation are elaborated. Two possible approaches for cellular based location estimation are investigated with the help of computer simulation. Their effectiveness and relative merits and demerits are identified. An algorithm specifically adapted for cellular environment is reported with specific features where mobiles, irrespective of their numbers, can locate their position without adversely loading the cellular system.Key Words: ITS, GSM, Cellular Radio, DRGS, GPS.
Effective electromechanical properties of cellular piezoelectret: A review
Institute of Scientific and Technical Information of China (English)
Yong-Ping Wan; Zheng Zhong
2012-01-01
Due to the large quasi-piezoelectric d33 coefficient in the film thickness direction,cellular piezoelectret has emerged as a new kind of compliant electromechanical transducer materials.The macroscopic piezoelectric effect of cellular piezoelectret is closely related to the void microstructures as well as the material constants of host polymer.Complex void microstructures are usually encountered in the optimum design of cellular piezoelectret polymer film with advanced piezoelectric properties.Analysis of the effective electromechanical properties is generally needed.This article presents an overview of the recent progress on theoretical models and numerical simulation for the effective electromechanical properties of cellular piezoelectret.Emphasis is placed on our own works of cellular piezoelectret published in past several years.
Cellular bioluminescence imaging.
Welsh, David K; Noguchi, Takako
2012-08-01
Bioluminescence imaging of live cells has recently been recognized as an important alternative to fluorescence imaging. Fluorescent probes are much brighter than bioluminescent probes (luciferase enzymes) and, therefore, provide much better spatial and temporal resolution and much better contrast for delineating cell structure. However, with bioluminescence imaging there is virtually no background or toxicity. As a result, bioluminescence can be superior to fluorescence for detecting and quantifying molecules and their interactions in living cells, particularly in long-term studies. Structurally diverse luciferases from beetle and marine species have been used for a wide variety of applications, including tracking cells in vivo, detecting protein-protein interactions, measuring levels of calcium and other signaling molecules, detecting protease activity, and reporting circadian clock gene expression. Such applications can be optimized by the use of brighter and variously colored luciferases, brighter microscope optics, and ultrasensitive, low-noise cameras. This article presents a review of how bioluminescence differs from fluorescence, its applications to cellular imaging, and available probes, optics, and detectors. It also gives practical suggestions for optimal bioluminescence imaging of single cells.
Cellular neurothekeoma with melanocytosis.
Wu, Ren-Chin; Hsieh, Yi-Yueh; Chang, Yi-Chin; Kuo, Tseng-Tong
2008-02-01
Cellular neurothekeoma (CNT) is a benign dermal tumor mainly affecting the head and neck and the upper extremities. It is characterized histologically by interconnecting fascicles of plump spindle or epithelioid cells with ample cytoplasm infiltrating in the reticular dermis. The histogenesis of CNT has been controversial, although it is generally regarded as an immature counterpart of classic/myxoid neurothekeoma, a tumor with nerve sheath differentiation. Two rare cases of CNT containing melanin-laden cells were described. Immunohistochemical study with NKI/C3, vimentin, epithelial membrane antigen, smooth muscle antigen, CD34, factor XIIIa, collagen type IV, S100 protein and HMB-45 was performed. Both cases showed typical growth pattern of CNT with interconnecting fascicles of epithelioid cells infiltrating in collagenous stroma. One of the nodules contained areas exhibiting atypical cytological features. Melanin-laden epithelioid or dendritic cells were diffusely scattered throughout one nodule, and focally present in the peripheral portion of the other nodule. Both nodules were strongly immunoreactive to NKI/C3 and vimentin, but negative to all the other markers employed. CNT harboring melanin-laden cells may pose diagnostic problems because of their close resemblance to nevomelanocytic lesions and other dermal mesenchymal tumors. These peculiar cases may also provide further clues to the histogenesis of CNT.
Knowledge discovery for geographical cellular automata
Institute of Scientific and Technical Information of China (English)
LI Xia; Anthony Gar-On Yeh
2005-01-01
This paper proposes a new method for geographical simulation by applying data mining techniques to cellular automata. CA has strong capabilities in simulating complex systems. The core of CA is how to define transition rules. There are no good methods for defining these transition rules. They are usually defined by using heuristic methods and thus subject to uncertainties. Mathematical equations are used to represent transition rules implicitly and have limitations in capturing complex relationships. This paper demonstrates that the explicit transition rules of CA can be automatically reconstructed through the rule induction procedure of data mining. The proposed method can reduce the influences of individual knowledge and preferences in defining transition rules and generate more reliable simulation results. It can efficiently discover knowledge from a vast volume of spatial data.
Partitioned quantum cellular automata are intrinsically universal
Arrighi, Pablo
2010-01-01
There have been several non-axiomatic approaches taken to define Quantum Cellular Automata (QCA). Partitioned QCA (PQCA) are the most canonical of these non-axiomatic definitions. In this work we show that any QCA can be put into the form of a PQCA. Our construction reconciles all the non-axiomatic definitions of QCA, showing that they can all simulate one another, and hence that they are all equivalent to the axiomatic definition. This is achieved by defining generalised n-dimensional intrinsic simulation, which brings the computer science based concepts of simulation and universality closer to theoretical physics. The result is not only an important simplification of the QCA model, it also plays a key role in the identification of a minimal n-dimensional intrinsically universal QCA.
SEM++: A particle model of cellular growth, signaling and migration
Milde, Florian; Tauriello, Gerardo; Haberkern, Hannah; Koumoutsakos, Petros
2014-06-01
We present a discrete particle method to model biological processes from the sub-cellular to the inter-cellular level. Particles interact through a parametrized force field to model cell mechanical properties, cytoskeleton remodeling, growth and proliferation as well as signaling between cells. We discuss the guiding design principles for the selection of the force field and the validation of the particle model using experimental data. The proposed method is integrated into a multiscale particle framework for the simulation of biological systems.
Interference cancellation technique under imperfect synchronization in cellular systems
Institute of Scientific and Technical Information of China (English)
WANG; Xin; WU; Zhuo
2009-01-01
In this paper, an asynchronous cooperative cellular system applied with space-time block coding(STBC)is investigated. A signal detector is proposed based on parallel interference cancellation(PIC), to cancel the inter-symbol interference(ISI)caused by the imperfect synchronization. Simulation results show that the proposed PIC detector can effectively suppress the ISI, but there is still a comparatively high error floor, due to the co-channel interference(CCI)of the cellular system.
Reactive Programming of Cellular Automata
Boussinot, Frédéric
2004-01-01
Implementation of cellular automata using reactive programming gives a way to code cell behaviors in an abstract and modular way. Multiprocessing also becomes possible. The paper describes the implementation of cellular automata with the reactive programming language LOFT, a thread-based extension of C. Self replicating loops considered in artificial life are coded to show the interest of the approach.
Experiences with a simplified microsimulation for the Dallas/Fort Worth area
Rickert, M; Nagel, Kai
1997-01-01
We describe a simple framework for micro simulation of city traffic. A medium sized excerpt of Dallas was used to examine different levels of simulation fidelity of a cellular automaton method for the traffic flow simulation and a simple intersection model. We point out problems arising with the granular structure of the underlying rules of motion.
Kim, HyunJin; Choi, Kang-Il; Choi, Sang-Il
2015-01-01
This paper proposes a memory-efficient bit-split string matching scheme for deep packet inspection (DPI). When the number of target patterns becomes large, the memory requirements of the string matching engine become a critical issue. The proposed string matching scheme reduces the memory requirements using the uniqueness of the target patterns in the deterministic finite automaton (DFA)-based bit-split string matching. The pattern grouping extracts a set of unique patterns from the target patterns. In the set of unique patterns, a pattern is not the suffix of any other patterns. Therefore, in the DFA constructed with the set of unique patterns, when only one pattern can be matched in an output state. In the bit-split string matching, multiple finite-state machine (FSM) tiles with several input bit groups are adopted in order to reduce the number of stored state transitions. However, the memory requirements for storing the matching vectors can be large because each bit in the matching vector is used to identify whether its own pattern is matched or not. In our research, the proposed pattern grouping is applied to the multiple FSM tiles in the bit-split string matching. For the set of unique patterns, the memory-based bit-split string matching engine stores only the pattern match index for each state to indicate the match with its own unique pattern. Therefore, the memory requirements are significantly decreased by not storing the matching vectors in the string matchers for the set of unique patterns. The experimental results show that the proposed string matching scheme can reduce the storage cost significantly compared to the previous bit-split string matching methods.
An efficient Cellular Potts Model algorithm that forbids cell fragmentation
Durand, Marc; Guesnet, Etienne
2016-11-01
The Cellular Potts Model (CPM) is a lattice based modeling technique which is widely used for simulating cellular patterns such as foams or biological tissues. Despite its realism and generality, the standard Monte Carlo algorithm used in the scientific literature to evolve this model preserves connectivity of cells on a limited range of simulation temperature only. We present a new algorithm in which cell fragmentation is forbidden for all simulation temperatures. This allows to significantly enhance realism of the simulated patterns. It also increases the computational efficiency compared with the standard CPM algorithm even at same simulation temperature, thanks to the time spared in not doing unrealistic moves. Moreover, our algorithm restores the detailed balance equation, ensuring that the long-term stage is independent of the chosen acceptance rate and chosen path in the temperature space.
Station Model for Rail Transit System Using Cellular Automata
Institute of Scientific and Technical Information of China (English)
XUN Jing; NING Bin; LI Ke-Ping
2009-01-01
In this paper, we propose a new cellular automata model to simulate the railway traffic at station.Based on NaSch model, the proposed station model is composed of the main track and the siding track.Two different schemes for trains passing through station are considered.One is the scheme of "pass by the main track, start and stop by the siding track".The other is the scheme of "two tracks play the same role".We simulate the train movement using the proposed model and analyze the traffic flow at station.The simulation results demonstrate that the proposed cellular automata model can be successfully used for the simulations of railway traffic.Some characteristic behaviors of railway traffic flow can be reproduced.Moreover, the simulation values of the minimum headway are close to the theoretical values.This result demonstrates the dependability and availability of the proposed model.
Dynamic Channel Allocation in Sectored Cellular Systems
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
It is known that dynamic channel assignment(DCA) strategy outperforms the fixed channel assignment(FCA) strategy in omni-directional antenna cellular systems. One of the most important methods used in DCA was channel borrowing. But with the emergence of cell sectorization and spatial division multiple access(SDMA) which are used to increase the capacity of cellular systems, the channel assignment faces a series of new problems. In this paper, a dynamic channel allocation scheme based on sectored cellular systems is proposed. By introducing intra-cell channel borrowing (borrowing channels from neighboring sectors) and inter-cell channel borrowing (borrowing channels from neighboring cells) methods, previous DCA strategies, including compact pattern based channel borrowing(CPCB) and greedy based dynamic channel assignment(GDCA) schemes proposed by the author, are improved significantly. The computer simulation shows that either intra-cell borrowing scheme or inter-cell borrowing scheme is efficient enough to uniform and non-uniform traffic service distributions.
Cellular systems biology profiling applied to cellular models of disease.
Giuliano, Kenneth A; Premkumar, Daniel R; Strock, Christopher J; Johnston, Patricia; Taylor, Lansing
2009-11-01
Building cellular models of disease based on the approach of Cellular Systems Biology (CSB) has the potential to improve the process of creating drugs as part of the continuum from early drug discovery through drug development and clinical trials and diagnostics. This paper focuses on the application of CSB to early drug discovery. We discuss the integration of protein-protein interaction biosensors with other multiplexed, functional biomarkers as an example in using CSB to optimize the identification of quality lead series compounds.
Distributed Algorithm Simulation Using Input/Output Automata
1990-09-01
include: " leader election : Choose exactly one distinguished "leader" process (to coordinate some computation). " mutual exclusion: Grant permission for...mechanisms for defining I/O automaton types. Section 3.4 contains an example of an automaton type for LeLann’s leader election algorithm [39]. Finally...e. status ,"announced") Figure 3-1: Automaton types for LeLann’s leader election algorithm. 3.5. SUPPORT FOR VERIFICATION, ANALYSIS, AND
Institute of Scientific and Technical Information of China (English)
阮聪; 孙晓民; 宋亦旭
2015-01-01
利用仿真方法从原子尺度研究薄膜生长过程是当前薄膜研究领域的热点。目前，仿真方法主要在纳米尺度模型实现，时空需求很大。针对这一问题，本文提出元胞和蒙特卡洛相结合的模拟方法，实现对微米尺度模型薄膜生长过程的模拟。利用元胞方法来实现模型表示以及演化计算，从而降低对内存空间的要求，提高计算效率，并使用蒙特卡洛方法计算粒子的扩散概率。通过对氮化硅薄膜生长过程进行具体研究，将模拟结果与实际实验结果和分子动力学演化结果进行表面形貌和成分的比较，验证了该方法的有效性。%Study on simulation method for the thin film growth processes on atomic scale is currently a hot research field. The simulation method mainly aiming at nanometer scale model demands huge computational cost and memory cost. In order to solve the problem, a cellular method combined with Monte Carlo method is presented in this article to simulate the growth processes of thin film on micron scale. Based on cellular method for model representation and evolutionary computation, we greatly reduce the memory requirements and improve the eﬃciency of computation, and the Monte Carlo method is used to determine the particle migration. Moreover, specific research on the growth process of silicon nitride thin film is implemented, and the simulation results are compared with the experimental data and the molecular dynamics simulation results of the surface morphology and composition, so as to verify the effectiveness of this method.
Combinatorial approaches to evaluate nanodiamond uptake and induced cellular fate.
Eldawud, Reem; Reitzig, Manuela; Opitz, Jörg; Rojansakul, Yon; Jiang, Wenjuan; Nangia, Shikha; Dinu, Cerasela Zoica
2016-02-26
Nanodiamonds (NDs) are an emerging class of engineered nanomaterials that hold great promise for the next generation of bionanotechnological products to be used for drug and gene delivery, or for bio-imaging and biosensing. Previous studies have shown that upon their cellular uptake, NDs exhibit high biocompatibility in various in vitro and in vivo set-ups. Herein we hypothesized that the increased NDs biocompatibility is a result of minimum membrane perturbations and their reduced ability to induce disruption or damage during cellular translocation. Using multi-scale combinatorial approaches that simulate ND-membrane interactions, we correlated NDs real-time cellular uptake and kinetics with the ND-induced membrane fluctuations to derive energy requirements for the uptake to occur. Our discrete and real-time analyses showed that the majority of NDs internalization occurs within 2 h of cellular exposure, however, with no effects on cellular viability, proliferation or cellular behavior. Furthermore, our simulation analyses using coarse-grained models identified key changes in the energy profile, membrane deformation and recovery time, all functions of the average ND or ND-based agglomerate size. Understanding the mechanisms responsible for ND-cell membrane interactions could possibly advance their implementation in various biomedical applications.
Combinatorial approaches to evaluate nanodiamond uptake and induced cellular fate
Eldawud, Reem; Reitzig, Manuela; Opitz, Jörg; Rojansakul, Yon; Jiang, Wenjuan; Nangia, Shikha; Zoica Dinu, Cerasela
2016-02-01
Nanodiamonds (NDs) are an emerging class of engineered nanomaterials that hold great promise for the next generation of bionanotechnological products to be used for drug and gene delivery, or for bio-imaging and biosensing. Previous studies have shown that upon their cellular uptake, NDs exhibit high biocompatibility in various in vitro and in vivo set-ups. Herein we hypothesized that the increased NDs biocompatibility is a result of minimum membrane perturbations and their reduced ability to induce disruption or damage during cellular translocation. Using multi-scale combinatorial approaches that simulate ND-membrane interactions, we correlated NDs real-time cellular uptake and kinetics with the ND-induced membrane fluctuations to derive energy requirements for the uptake to occur. Our discrete and real-time analyses showed that the majority of NDs internalization occurs within 2 h of cellular exposure, however, with no effects on cellular viability, proliferation or cellular behavior. Furthermore, our simulation analyses using coarse-grained models identified key changes in the energy profile, membrane deformation and recovery time, all functions of the average ND or ND-based agglomerate size. Understanding the mechanisms responsible for ND-cell membrane interactions could possibly advance their implementation in various biomedical applications.
A Course in Cellular Bioengineering.
Lauffenburger, Douglas A.
1989-01-01
Gives an overview of a course in chemical engineering entitled "Cellular Bioengineering," dealing with how chemical engineering principles can be applied to molecular cell biology. Topics used are listed and some key references are discussed. Listed are 85 references. (YP)
Individual-based lattice model for spatial spread of epidemics
Directory of Open Access Journals (Sweden)
Henryk Fuks
2001-01-01
Full Text Available We present a lattice gas cellular automaton (LGCA to study spatial and temporal dynamics of an epidemic of SIR (susceptible-infected-removed type. The automaton is fully discrete, i.e., space, time and number of individuals are discrete variables. The automaton can be applied to study spread of epidemics in both human and animal populations. We investigate effects of spatial inhomogeneities in initial distribution of infected and vaccinated populations on the dynamics of epidemic of SIR type. We discuss vaccination strategies which differ only in spatial distribution of vaccinated individuals. Also, we derive an approximate, mean-field type description of the automaton, and discuss differences between the mean-field dynamics and the results ofLGCA simulation.
Energy Landscape of Cellular Networks
Wang, Jin
2008-03-01
Cellular Networks are in general quite robust and perform their biological functions against the environmental perturbations. Progresses have been made from experimental global screenings, topological and engineering studies. However, there are so far few studies of why the network should be robust and perform biological functions from global physical perspectives. In this work, we will explore the global properties of the network from physical perspectives. The aim of this work is to develop a conceptual framework and quantitative physical methods to study the global nature of the cellular network. The main conclusion of this presentation is that we uncovered the underlying energy landscape for several small cellular networks such as MAPK signal transduction network and gene regulatory networks, from the experimentally measured or inferred inherent chemical reaction rates. The underlying dynamics of these networks can show bi-stable as well as oscillatory behavior. The global shapes of the energy landscapes of the underlying cellular networks we have studied are robust against perturbations of the kinetic rates and environmental disturbances through noise. We derived a quantitative criterion for robustness of the network function from the underlying landscape. It provides a natural explanation of the robustness and stability of the network for performing biological functions. We believe the robust landscape is a global universal property for cellular networks. We believe the robust landscape is a quantitative realization of Darwinian principle of natural selection at the cellular network level. It may provide a novel algorithm for optimizing the network connections, which is crucial for the cellular network design and synthetic biology. Our approach is general and can be applied to other cellular networks.
Mathematical Modeling of Cellular Metabolism.
Berndt, Nikolaus; Holzhütter, Hermann-Georg
2016-01-01
Cellular metabolism basically consists of the conversion of chemical compounds taken up from the extracellular environment into energy (conserved in energy-rich bonds of organic phosphates) and a wide array of organic molecules serving as catalysts (enzymes), information carriers (nucleic acids), and building blocks for cellular structures such as membranes or ribosomes. Metabolic modeling aims at the construction of mathematical representations of the cellular metabolism that can be used to calculate the concentration of cellular molecules and the rates of their mutual chemical interconversion in response to varying external conditions as, for example, hormonal stimuli or supply of essential nutrients. Based on such calculations, it is possible to quantify complex cellular functions as cellular growth, detoxification of drugs and xenobiotic compounds or synthesis of exported molecules. Depending on the specific questions to metabolism addressed, the methodological expertise of the researcher, and available experimental information, different conceptual frameworks have been established, allowing the usage of computational methods to condense experimental information from various layers of organization into (self-) consistent models. Here, we briefly outline the main conceptual frameworks that are currently exploited in metabolism research.
The Urge to Merge: When Cellular Service Providers Pool Capacity
Hua, Sha; Panwar, Shivendra
2011-01-01
As cellular networks are turning into a platform for ubiquitous data access, cellular operators are facing a severe data capacity crisis due to the exponential growth of traffic generated by mobile users. In this work, we investigate the benefits of sharing infrastructure and spectrum among two cellular operators. Specifically, we provide a multi-cell analytical model using stochastic geometry to identify the performance gain under different sharing strategies, which gives tractable and accurate results. To validate the performance using a realistic setting, we conduct extensive simulations for a multi-cell OFDMA system using real base station locations. Both analytical and simulation results show that even a simple cooperation strategy between two similar operators, where they share spectrum and base stations, roughly quadruples capacity as compared to the capacity of a single operator. This is equivalent to doubling the capacity per customer, providing a strong incentive for operators to cooperate, if not a...
Institute of Scientific and Technical Information of China (English)
李锰; 杨峰
2011-01-01
For the purpose of investigating conditions of earthquake pregnancy,a heterogeneous 2-D single fault model with 81×81 cells is set up. By using cellular automata models and changing the model heterogeneity and correlation parameters respectively,we compute and get different synthetic event catalogues for analyzing general seismic activity and intensity distribution properties. The computation results show that different heterogeneous structures produce different seismic sequence types and G-R relation,so the heterogeneity is an important influencing factor on seismicity. Nevertheless ,both the coefficients of stress redistribution and local friction loss can also influence seimicity to some extent. It is possibly helpful for further understandings of earthquake process complexity.%基于细胞自动机模型,构建了由81×81个细胞单元组成非均匀二维单断层介质样本,研究了断层结构细观非均匀性以及相关模型参数变化对模拟输出结果和强度分布特征的影响.研究结果表明:结构非均匀性是影响地震活动性的控制性参量,随着非均匀程度的增强,地震事件数量增多,震级分布变得越来越均匀,破裂演化模式由相对“脆性”向“塑性”变化；介质结构的初始条件和应力加载的随机性对地震活动演化过程基本不产生影响,此外,应力降分配系数减小使b值主体线性段向大震级延伸；随着局部摩擦损耗系数增大,模拟地震事件的数量有所增加,大震级事件数量和震级衰减增强,b值主体线性区间变窄,使断层的变形破坏方式由相对“脆性”向“塑性”变化.这些对理解孕震过程的复杂性是有帮助的.
Digital implementation of shunting-inhibitory cellular neural network
Hammadou, Tarik; Bouzerdoum, Abdesselam; Bermak, Amine
2000-05-01
Shunting inhibition is a model of early visual processing which can provide contrast and edge enhancement, and dynamic range compression. An architecture of digital Shunting Inhibitory Cellular Neural Network for real time image processing is presented. The proposed architecture is intended to be used in a complete vision system for edge detection and image enhancement. The present hardware architecture, is modeled and simulated in VHDL. Simulation results show the functional validity of the proposed architecture.
基于一维人工细胞自动机的肿瘤生长模型研究%A TUMOR GROWTH MODEL DESIGNED WITH A ONE DIMENSIONAL CELLULAR AUTOMATON
Institute of Scientific and Technical Information of China (English)
阮晓刚; 胡日查
2003-01-01
通过对Gompertz肿瘤生长理论模型的研究和分析,设计了一种基于一维人工细胞自动机的肿瘤生长模型(TGM1dCA).在连续Gompertz模型基础上,论文导出了Gompertz模型的离散差分形式.运用离散Gompertz模型,论文设计出了体现肿瘤生长动态的人工细胞自动机状态随机演化规则.论文对TGM1dCA细胞自动机进行了理论分析和仿真实验,理论分析和仿真实验结果表明,TGM1dCA细胞自动机与Gompertz模型和临床实验数据具有良好的一致性.
Institute of Scientific and Technical Information of China (English)
秦大康; 江志松
2008-01-01
使用禁止字理论、计算机搜索和符号动力学的方法对7号初等元胞自动机生成的时间序列从形式语言的角度进行复杂性分析,确定了禁止字集及其Chomsky层次,确定了演化语言的一个精简的Chomsky层次,并由此得到了时间序列的完整描述.
Institute of Scientific and Technical Information of China (English)
陈建华; 涂文洋
2016-01-01
The correlation of geographic space has been significantly changed with the emergence of computer networks. In networked geographic spaces, network traffics that related to specific events, phenomena, or messages may lead to a particular group spatial-temporal distribution pattern when they reach a certain level. Therefore, for specific or targeted audiences, this will give rise to an unexpected result. Due to the characteristics of networked geographic space, by combining computer networks with geography, this paper built a cellular automata simulation model for networked geographic spaces. Simulation results show that:(1) there are five types of distributions for the cellular views in networked geographic spaces;(2) cellular spatial aggregation patterns exist in those spaces. The results can help us better understand the impact of information flow, which is related to specific events, phenomena, or messages, on the group spatial-temporal patterns in networked geographic spaces. They also provide the basis for analyzing the group spatial-temporal distributions of specific events.%计算机网络的出现，显著地改变了地理空间的相关性。在网络化地理空间中，相关事件、现象、消息的特定网络信息流达到一定程度时，可能引发并塑造群体的特定时空分布格局。因此，针对网络化地理空间特性，基于元胞自动机模型，构建了网络化地理空间元胞自动机仿真模型。仿真实验结果表明：(1)网络化地理空间中，元胞群体意见存在5种分布；(2)元胞在空间上呈现出聚集的时空分布格局。研究结果将有助于理解网络化地理空间中针对特定事件、现象、消息的信息流对群体时空分布格局的影响，为网络环境下特定事件、现象的群体时空分布格局分析提供依据。
Hierarchical Cellular Structures in High-Capacity Cellular Communication Systems
Jain, R K; Agrawal, N K
2011-01-01
In the prevailing cellular environment, it is important to provide the resources for the fluctuating traffic demand exactly in the place and at the time where and when they are needed. In this paper, we explored the ability of hierarchical cellular structures with inter layer reuse to increase the capacity of mobile communication network by applying total frequency hopping (T-FH) and adaptive frequency allocation (AFA) as a strategy to reuse the macro and micro cell resources without frequency planning in indoor pico cells [11]. The practical aspects for designing macro- micro cellular overlays in the existing big urban areas are also explained [4]. Femto cells are inducted in macro / micro / pico cells hierarchical structure to achieve the required QoS cost effectively.
Half-Cell Law of Regular Cellular Detonations
Institute of Scientific and Technical Information of China (English)
WANG Chun; JIANG Zong-Lin; GAO Yun-Liang
2008-01-01
Numerical simulations illustrate the half-cell law of regular cellular detonations propagating in confined space,i.e., the number of cells always maintains an integral multiple of half cell. The cells adapt themselves larger or smaller to the size of the unconfined space by maintaining the cell scale larger or smaller than the original cells of detonation.
Parallelizing the Cellular Potts Model on graphics processing units
Tapia, José Juan; D'Souza, Roshan M.
2011-04-01
The Cellular Potts Model (CPM) is a lattice based modeling technique used for simulating cellular structures in computational biology. The computational complexity of the model means that current serial implementations restrict the size of simulation to a level well below biological relevance. Parallelization on computing clusters enables scaling the size of the simulation but marginally addresses computational speed due to the limited memory bandwidth between nodes. In this paper we present new data-parallel algorithms and data structures for simulating the Cellular Potts Model on graphics processing units. Our implementations handle most terms in the Hamiltonian, including cell-cell adhesion constraint, cell volume constraint, cell surface area constraint, and cell haptotaxis. We use fine level checkerboards with lock mechanisms using atomic operations to enable consistent updates while maintaining a high level of parallelism. A new data-parallel memory allocation algorithm has been developed to handle cell division. Tests show that our implementation enables simulations of >10 cells with lattice sizes of up to 256 3 on a single graphics card. Benchmarks show that our implementation runs ˜80× faster than serial implementations, and ˜5× faster than previous parallel implementations on computing clusters consisting of 25 nodes. The wide availability and economy of graphics cards mean that our techniques will enable simulation of realistically sized models at a fraction of the time and cost of previous implementations and are expected to greatly broaden the scope of CPM applications.
Lattice gas hydrodynamics: Theory and simulations. Final report
Energy Technology Data Exchange (ETDEWEB)
Hasslacher, B.
1993-05-01
The first successful application of a microscopic analogy to create a skeleton cellular automaton and analyze it with statistical mechanical tools, was the work of Frisch, Hasslacher and Pomeau on the Navier-Stokes equation in two and three dimensions. This has become a very large research area with lattice gas models and methods being used for both fundamental investigations into the foundations of statistical mechanics and a large number of diverse applications. This present research was devoted to enlarging the fundamental scope of lattice gas models and proved quite successful. Since the beginning of this proposal, cellular automata have been constructed for statistical mechanical models, fluids, diffusion and shock systems in fundamental investigations. In applied areas, there are now excellent lattice gas models for complex flows through porous media, chemical reaction and combustion dynamics, multiphase flow systems, and fluid mixtures with natural boundaries. With extended cellular fluid models, one can do problems with arbitrary pairwise potentials. Recently, these have been applied to such problems as non-newtonian or polymeric liquids and a mixture of immiscible fluids passing through fractal or spongelike media in two and three dimensions. This proposal has contributed to and enlarged the scope of this work.
Experiences with a Simplified Microsimulation for the Dallas/Fort-Worth Area
Rickert, M.; Nagel, K.
We describe a simple framework for microsimulation of city traffic. A medium-sized excerpt of Dallas was used to examine different levels of simulation fidelity of a cellular automaton method for the traffic flow simulation and a simple intersection model. We point out problems arising with the granular structure of the underlying rules of motion.
Prognosis of Different Cellular Generations
Directory of Open Access Journals (Sweden)
Preetish Ranjan
2013-04-01
Full Text Available Technological advancement in mobile telephony from 1G to 3G, 4G and 5G has a very axiomatic fact that made an entire world a global village. The cellular system employs a different design approach and technology that most commercial radio and television system use. In the cellular system, the service area is divided into cells and a transmitter is designed to serve an individual cell. The system seeks to make efficient use of available channels by using low-power transmitters to allow frequency reuse at a smaller distance. Maximizing the number of times each channel can be reused in a given geographical area is the key to an efficient cellular system design. During the past three decades, the world has seen significant changes in telecommunications industry. There have been some remarkable aspects to the rapid growth in wireless communications, as seen by the large expansion in mobile systems. This paper focuses on “Past, Present & Future of Cellular Telephony” and some light has been thrown upon the technologies of the cellular systems, namely 1G, 2G, 2.5G, 3G and future generations like 4G and 5G systems as well.
Dalmasso, Giovanni; Marin Zapata, Paula Andrea; Brady, Nathan Ryan; Hamacher-Brady, Anne
2017-01-01
Mitochondria are semi-autonomous organelles that supply energy for cellular biochemistry through oxidative phosphorylation. Within a cell, hundreds of mobile mitochondria undergo fusion and fission events to form a dynamic network. These morphological and mobility dynamics are essential for maintaining mitochondrial functional homeostasis, and alterations both impact and reflect cellular stress states. Mitochondrial homeostasis is further dependent on production (biogenesis) and the removal of damaged mitochondria by selective autophagy (mitophagy). While mitochondrial function, dynamics, biogenesis and mitophagy are highly-integrated processes, it is not fully understood how systemic control in the cell is established to maintain homeostasis, or respond to bioenergetic demands. Here we used agent-based modeling (ABM) to integrate molecular and imaging knowledge sets, and simulate population dynamics of mitochondria and their response to environmental energy demand. Using high-dimensional parameter searches we integrated experimentally-measured rates of mitochondrial biogenesis and mitophagy, and using sensitivity analysis we identified parameter influences on population homeostasis. By studying the dynamics of cellular subpopulations with distinct mitochondrial masses, our approach uncovered system properties of mitochondrial populations: (1) mitochondrial fusion and fission activities rapidly establish mitochondrial sub-population homeostasis, and total cellular levels of mitochondria alter fusion and fission activities and subpopulation distributions; (2) restricting the directionality of mitochondrial mobility does not alter morphology subpopulation distributions, but increases network transmission dynamics; and (3) maintaining mitochondrial mass homeostasis and responding to bioenergetic stress requires the integration of mitochondrial dynamics with the cellular bioenergetic state. Finally, (4) our model suggests sources of, and stress conditions amplifying
Institute of Scientific and Technical Information of China (English)
李锰; 杨峰; 胡伟华
2011-01-01
为解释实际观测资料震源破裂过程与自相似(分形)模型的不一致性,本文基于观测结果,构建了由81×81个细胞单元组成二维非均匀断层模型,并通过设计的细胞自动机模拟程序进行了模拟试验.研究结果表明:断层结构非均匀性是影响孕震过程特征的重要因素,而且地震强度分布并非简单的自相似.随着断层非匀质性增加,破裂过程出现由相对的脆性破坏向塑性破坏特征变化的趋势.利用细胞自动机不仅能较好地解释震级-频度关系中的大、小震级段低头现象,而且也可解释大震级事件具有相对恒定的应力降,得到了与实际观测研究相一致的结果.%In the paper, three kinds of heterogeneous faults with 81 ×81 cells are set up using celluar automata models and simulated for explaining the inconsistency between the observations and fractal-based model. The results show that the G-R relations behave not in simple self-similarity but multi-fractal, and with the increasing of heterogeneity the fracture process tends to turn from brittle to plastic behaviors. At the same time, using the models can explain not only the curvature at smaller and larger magnitudes in G-R relation but also the relatively constant stress drop for larger magnitude earthquake events.Fault structural heterogeneity plays a important role in earthquake preparation process.The results from computer simulation are consistent with observations from detailed seismicity studies.
Novel Materials for Cellular Nanosensors
DEFF Research Database (Denmark)
Sasso, Luigi
The monitoring of cellular behavior is useful for the advancement of biomedical diagnostics, drug development and the understanding of a cell as the main unit of the human body. Micro- and nanotechnology allow for the creation of functional devices that enhance the study of cellular dynamics...... modifications for electrochemical nanosensors for the detection of analytes released from cells. Two type of materials were investigated, each pertaining to the two different aspects of such devices: peptide nanostructures were studied for the creation of cellular sensing substrates that mimic in vivo surfaces...... and that offer advantages of functionalization, and conducting polymers were used as electrochemical sensor surface modifications for increasing the sensitivity towards relevant analytes, with focus on the detection of dopamine released from cells via exocytosis. Vertical peptide nanowires were synthesized from...
Cellular models for Parkinson's disease.
Falkenburger, Björn H; Saridaki, Theodora; Dinter, Elisabeth
2016-10-01
Developing new therapeutic strategies for Parkinson's disease requires cellular models. Current models reproduce the two most salient changes found in the brains of patients with Parkinson's disease: The degeneration of dopaminergic neurons and the existence of protein aggregates consisting mainly of α-synuclein. Cultured cells offer many advantages over studying Parkinson's disease directly in patients or in animal models. At the same time, the choice of a specific cellular model entails the requirement to focus on one aspect of the disease while ignoring others. This article is intended for researchers planning to use cellular models for their studies. It describes for commonly used cell types the aspects of Parkinson's disease they model along with technical advantages and disadvantages. It might also be helpful for researchers from other fields consulting literature on cellular models of Parkinson's disease. Important models for the study of dopaminergic neuron degeneration include Lund human mesencephalic cells and primary neurons, and a case is made for the use of non-dopaminergic cells to model pathogenesis of non-motor symptoms of Parkinson's disease. With regard to α-synuclein aggregates, this article describes strategies to induce and measure aggregates with a focus on fluorescent techniques. Cellular models reproduce the two most salient changes of Parkinson's disease, the degeneration of dopaminergic neurons and the existence of α-synuclein aggregates. This article is intended for researchers planning to use cellular models for their studies. It describes for commonly used cell types and treatments the aspects of Parkinson's disease they model along with technical advantages and disadvantages. Furthermore, this article describes strategies to induce and measure aggregates with a focus on fluorescent techniques. This article is part of a special issue on Parkinson disease.
Cellular basis of Alzheimer's disease.
Bali, Jitin; Halima, Saoussen Ben; Felmy, Boas; Goodger, Zoe; Zurbriggen, Sebastian; Rajendran, Lawrence
2010-12-01
Alzheimer's disease (AD) is the most common form of neurodegenerative disease. A characteristic feature of the disease is the presence of amyloid-β (Aβ) which either in its soluble oligomeric form or in the plaque-associated form is causally linked to neurodegeneration. Aβ peptide is liberated from the membrane-spanning -amyloid precursor protein by sequential proteolytic processing employing β- and γ-secretases. All these proteins involved in the production of Aβ peptide are membrane associated and hence, membrane trafficking and cellular compartmentalization play important roles. In this review, we summarize the key cellular events that lead to the progression of AD.
Evolving Transport Networks With Cellular Automata Models Inspired by Slime Mould.
Tsompanas, Michail-Antisthenis I; Sirakoulis, Georgios Ch; Adamatzky, Andrew I
2015-09-01
Man-made transport networks and their design are closely related to the shortest path problem and considered amongst the most debated problems of computational intelligence. Apart from using conventional or bio-inspired computer algorithms, many researchers tried to solve this kind of problem using biological computing substrates, gas-discharge solvers, prototypes of a mobile droplet, and hot ice computers. In this aspect, another example of biological computer is the plasmodium of acellular slime mould Physarum polycephalum (P. polycephalum), which is a large single cell visible by an unaided eye and has been proven as a reliable living substrate for implementing biological computing devices for computational geometry, graph-theoretical problems, and optimization and imitation of transport networks. Although P. polycephalum is easy to experiment with, computing devices built with the living slime mould are extremely slow; it takes slime mould days to execute a computation. Consequently, mapping key computing mechanisms of the slime mould onto silicon would allow us to produce efficient bio-inspired computing devices to tackle with hard to solve computational intelligence problems like the aforementioned. Toward this direction, a cellular automaton (CA)-based, Physarum-inspired, network designing model is proposed. This novel CA-based model is inspired by the propagating strategy, the formation of tubular networks, and the computing abilities of the plasmodium of P. polycephalum. The results delivered by the CA model demonstrate a good match with several previously published results of experimental laboratory studies on imitation of man-made transport networks with P. polycephalum. Consequently, the proposed CA model can be used as a virtual, easy-to-access, and biomimicking laboratory emulator that will economize large time periods needed for biological experiments while producing networks almost identical to the tubular networks of the real-slime mould.
Scalable asynchronous execution of cellular automata
Folino, Gianluigi; Giordano, Andrea; Mastroianni, Carlo
2016-10-01
The performance and scalability of cellular automata, when executed on parallel/distributed machines, are limited by the necessity of synchronizing all the nodes at each time step, i.e., a node can execute only after the execution of the previous step at all the other nodes. However, these synchronization requirements can be relaxed: a node can execute one step after synchronizing only with the adjacent nodes. In this fashion, different nodes can execute different time steps. This can be a notable advantageous in many novel and increasingly popular applications of cellular automata, such as smart city applications, simulation of natural phenomena, etc., in which the execution times can be different and variable, due to the heterogeneity of machines and/or data and/or executed functions. Indeed, a longer execution time at a node does not slow down the execution at all the other nodes but only at the neighboring nodes. This is particularly advantageous when the nodes that act as bottlenecks vary during the application execution. The goal of the paper is to analyze the benefits that can be achieved with the described asynchronous implementation of cellular automata, when compared to the classical all-to-all synchronization pattern. The performance and scalability have been evaluated through a Petri net model, as this model is very useful to represent the synchronization barrier among nodes. We examined the usual case in which the territory is partitioned into a number of regions, and the computation associated with a region is assigned to a computing node. We considered both the cases of mono-dimensional and two-dimensional partitioning. The results show that the advantage obtained through the asynchronous execution, when compared to the all-to-all synchronous approach is notable, and it can be as large as 90% in terms of speedup.
Theory and Simulation for Traffic Characteristics on the Highway with a Slowdown Section.
Xu, Dejie; Mao, Baohua; Rong, Yaping; Wei, Wei
2015-01-01
We study the traffic characteristics on a single-lane highway with a slowdown section using the deterministic cellular automaton (CA) model. Based on the theoretical analysis, the relationships among local mean densities, velocities, traffic fluxes, and global densities are derived. The results show that two critical densities exist in the evolutionary process of traffic state, and they are significant demarcation points for traffic phase transition. Furthermore, the changing laws of the two critical densities with different length of limit section are also investigated. It is shown that only one critical density appears if a highway is not slowdown section; nevertheless, with the growing length of slowdown section, one critical density separates into two critical densities; if the entire highway is slowdown section, they finally merge into one. The contrastive analysis proves that the analytical results are consistent with the numerical ones.
On Cellular MIMO Channel Capacity
Adachi, Koichi; Adachi, Fumiyuki; Nakagawa, Masao
To increase the transmission rate without bandwidth expansion, the multiple-input multiple-output (MIMO) technique has recently been attracting much attention. The MIMO channel capacity in a cellular system is affected by the interference from neighboring co-channel cells. In this paper, we introduce the cellular channel capacity and evaluate its outage capacity, taking into account the frequency-reuse factor, path loss exponent, standard deviation of shadowing loss, and transmission power of a base station (BS). Furthermore, we compare the cellular MIMO downlink channel capacity with those of other multi-antenna transmission techniques such as single-input multiple-output (SIMO) and space-time block coded multiple-input single-output (STBC-MISO). We show that the optimum frequency-reuse factor F that maximizes 10%-outage capacity is 3 and both 50%- and 90%-outage capacities is 1 irrespective of the type of multi-antenna transmission technique, where q%-outage capacity is defined as the channel capacity that gives an outage probability of q%. We also show that the cellular MIMO channel capacity is always higher than those of SIMO and STBC-MISO.
Cellular uptake of metallated cobalamins
DEFF Research Database (Denmark)
Tran, MQT; Stürup, Stefan; Lambert, Ian H.;
2016-01-01
Cellular uptake of vitamin B12-cisplatin conjugates was estimated via detection of their metal constituents (Co, Pt, and Re) by inductively coupled plasma mass spectrometry (ICP-MS). Vitamin B12 (cyano-cob(iii)alamin) and aquo-cob(iii)alamin [Cbl-OH2](+), which differ in the β-axial ligands (CN(-...
模拟疏散中个体及群体运动方法%Individual and Crowd Activities in Evacuation Simulation
Institute of Scientific and Technical Information of China (English)
杨文举; 周洋洋; 常瑜
2012-01-01
Simulate crew's evacuation by using cellular automaton and artificial intelligence theory. Study the action of auto-path searching and the rule of crew's movement when the density of the crew reached a numerical value under the situation of "area division". We find out crew's action of obstacle avoiding and path searching under the condition of Area division is more likely to match the reality. Compared with the individual movement, crew's movement proved that with the same computer resource supplied, the number of evacuated crew has increased, at the same configuration of crowd, the time of evacuation does not change a lot The result indicates that Area division and "simulation of crew's movement" can reduce the impact on the result and in the meantime ensure the result's validity. It is a practical measure to simulate an urgent evacuation under a real situation.%应用元胞自动机和人工智能原理模拟人员的疏散,研究了“分块划分”情况下个体的智能寻径行为以及当出口人员密度达到一定阀值时群体运动的规律,发现分块划分条件下人员的行为与现实中人的寻径及避障行为更接近；采用“出口处群体运动”与单独采用个体运动算法相比,同等计算机资源条件下,最大疏散人数得到了提高,而在同等人员属性配置下,在一定范围内,疏散时间变化不大.结果表明分块划分与出口“群体运动模拟”能够减少硬件本身对结果的影响,从且保证了结果的有效性,是一种模拟真实场景紧急疏散的可行方法.
Uplink Power Saving Potential of Cellular System with Fixed Relays
Institute of Scientific and Technical Information of China (English)
SHI Hong-kui; RONG Meng-tian; LIU Tao; YU Dan
2007-01-01
This paper presented a scheme of relayed cellular mobile telecommunication network, which only employs fixed digital relays and not more than two-hop relay routes. Power saving potential of the network is deeply studied under the assumption of not occupying additional frequency bands (i. e. relays share the same frequency bands as used by the base stations). Theoretical analysis and simulation results have both shown that, with the same radio coverage requirement, the necessary effective transmission powers in such a relayed network have greatly decreased compared to conventional cellular network.
Lightweight 3D cellular composites inspired by balsa.
Malek, Sardar; Raney, Jordan; Lewis, Jennifer; Gibson, Lorna
2017-02-13
Additive manufacturing technologies offer new ways to fabricate cellular materials with composite cell walls, mimicking the structure and mechanical properties of woods. However, materials limitations and a lack of design tools have confined the usefulness of 3D printed cellular materials. We develop new carbon fiber reinforced, epoxy inks for 3D printing which result in printed materials with longitudinal Young's modulus up to 57 GPa (exceeding the longitudinal modulus of wood cell wall material). To guide the design of hierarchical cellular materials, we developed a parameterized, multi-scale, finite element model. Computational homogenization based on finite element simulations at multiple length scales is employed to obtain the elastic properties of the material at multiple length scales. Parameters affecting the elastic response of cellular composites, such as the volume fraction, orientation distribution, and aspect ratio of fibers within the cell walls as well as the cell geometry and relative density are included in the model. To validate the model, experiments are conducted on both solid carbon fiber/epoxy composites and cellular structures made from them, showing excellent agreement with model predictions, both at the cell-wall and at the cellular-structure levels. Using the model, cellular structures are designed and experimentally shown to achieve a specific stiffness nearly as high as that observed in balsa wood. The good agreement between the multi-scale model predictions and experimental data provides confidence in the practical utility of this model as a tool for designing novel 3D cellular composites with unprecedented specific elastic properties.
Cellular Automata Models for Diffusion of Innovations
Fuks, H; Fuks, Henryk; Boccara, Nino
1997-01-01
We propose a probabilistic cellular automata model for the spread of innovations, rumors, news, etc. in a social system. The local rule used in the model is outertotalistic, and the range of interaction can vary. When the range R of the rule increases, the takeover time for innovation increases and converges toward its mean-field value, which is almost inversely proportional to R when R is large. Exact solutions for R=1 and $R=\\infty$ (mean-field) are presented, as well as simulation results for other values of R. The average local density is found to converge to a certain stationary value, which allows us to obtain a semi-phenomenological solution valid in the vicinity of the fixed point n=1 (for large t).
A cellular automata evacuation model considering friction and repulsion
Institute of Scientific and Technical Information of China (English)
SONG Weiguo; YU Yanfei; FAN Weicheng; Zhang Heping
2005-01-01
There exist interactions among pedestrians and between pedestrian and environment in evacuation. These interactions include attraction, repulsion and friction that play key roles in human evacuation behaviors, speed and efficiency. Most former evacuation models focus on the attraction force, while repulsion and friction are not well modeled. As a kind of multi-particle self-driven model, the social force model introduced in recent years can represent those three forces but with low simulation efficiency because it is a continuous model with complex rules. Discrete models such as the cellular automata model and the lattice gas model have simple rules and high simulation efficiency, but are not quite suitable for interactions' simulation. In this paper, a new cellular automata model based on traditional models is introduced in which repulsion and friction are modeled quantitatively. It is indicated that the model can simulate some basic behaviors, e.g.arching and the "faster-is-slower" phenomenon, in evacuation as multi-particle self-driven models, but with high efficiency as the normal cellular automata model and the lattice gas model.
Error performance analysis in downlink cellular networks with interference management
Afify, Laila H.
2015-05-01
Modeling aggregate network interference in cellular networks has recently gained immense attention both in academia and industry. While stochastic geometry based models have succeeded to account for the cellular network geometry, they mostly abstract many important wireless communication system aspects (e.g., modulation techniques, signal recovery techniques). Recently, a novel stochastic geometry model, based on the Equivalent-in-Distribution (EiD) approach, succeeded to capture the aforementioned communication system aspects and extend the analysis to averaged error performance, however, on the expense of increasing the modeling complexity. Inspired by the EiD approach, the analysis developed in [1] takes into consideration the key system parameters, while providing a simple tractable analysis. In this paper, we extend this framework to study the effect of different interference management techniques in downlink cellular network. The accuracy of the proposed analysis is verified via Monte Carlo simulations.
Institute of Scientific and Technical Information of China (English)
赵明娟; 邓志成; 赵龙志
2015-01-01
基于元胞自动机法，结合 Moore 型邻居定义和晶粒生长理论，建立了增强相颗粒 SiC 对镁合金激光熔注中表层316L不锈钢晶粒生长的影响模型，模型考虑了晶界迁移率和晶界能等因素，实现了不同增强相颗粒体积分数和颗粒尺寸对晶粒生长影响的计算机模拟.结果表明，所建立的模型能较好的模拟晶粒生长过程，所得晶粒生长指数为0．42；增强相颗粒体积分数含量越高，晶粒生长越慢，晶粒尺寸越小；增强相颗粒尺寸越小，晶粒生长的越慢，晶粒尺寸越小，组织越均匀.%Based on the cellular automaton method,the definition of Moore neighbor type and the grain growth theory,a model of simulation for the grain growth process was established,which simulated the influence of the SiC reinforcement particles and 316L stainless steel reinforced the surface of magnesium alloy by laser melt inj ection.Many factors such as grain boundary mobility and grain boundary energy were considered in the mod-el.Simulated the influence of different volume fraction and size of reinforcement particles on the grain growth process were obtained.The results show that:the grain growth process can be simulated very well by the meth-od,the grain growth index can be obtained as 0.42;the higher volume fraction of the particles,the slower the speed of the grain growth,the smaller grain size;the smaller the particles size is,the slower the grain grows, the smaller grain size and the microstructure is more uniform.
Reversibly assembled cellular composite materials.
Cheung, Kenneth C; Gershenfeld, Neil
2013-09-13
We introduce composite materials made by reversibly assembling a three-dimensional lattice of mass-produced carbon fiber-reinforced polymer composite parts with integrated mechanical interlocking connections. The resulting cellular composite materials can respond as an elastic solid with an extremely large measured modulus for an ultralight material (12.3 megapascals at a density of 7.2 milligrams per cubic centimeter). These materials offer a hierarchical decomposition in modeling, with bulk properties that can be predicted from component measurements and deformation modes that can be determined by the placement of part types. Because site locations are locally constrained, structures can be produced in a relative assembly process that merges desirable features of fiber composites, cellular materials, and additive manufacturing.
Glycosylation regulates prestin cellular activity.
Rajagopalan, Lavanya; Organ-Darling, Louise E; Liu, Haiying; Davidson, Amy L; Raphael, Robert M; Brownell, William E; Pereira, Fred A
2010-03-01
Glycosylation is a common post-translational modification of proteins and is implicated in a variety of cellular functions including protein folding, degradation, sorting and trafficking, and membrane protein recycling. The membrane protein prestin is an essential component of the membrane-based motor driving electromotility changes (electromotility) in the outer hair cell (OHC), a central process in auditory transduction. Prestin was earlier identified to possess two N-glycosylation sites (N163, N166) that, when mutated, marginally affect prestin nonlinear capacitance (NLC) function in cultured cells. Here, we show that the double mutant prestin(NN163/166AA) is not glycosylated and shows the expected NLC properties in the untreated and cholesterol-depleted HEK 293 cell model. In addition, unlike WT prestin that readily forms oligomers, prestin(NN163/166AA) is enriched as monomers and more mobile in the plasma membrane, suggesting that oligomerization of prestin is dependent on glycosylation but is not essential for the generation of NLC in HEK 293 cells. However, in the presence of increased membrane cholesterol, unlike the hyperpolarizing shift in NLC seen with WT prestin, cells expressing prestin(NN163/166AA) exhibit a linear capacitance function. In an attempt to explain this finding, we discovered that both WT prestin and prestin(NN163/166AA) participate in cholesterol-dependent cellular trafficking. In contrast to WT prestin, prestin(NN163/166AA) shows a significant cholesterol-dependent decrease in cell-surface expression, which may explain the loss of NLC function. Based on our observations, we conclude that glycosylation regulates self-association and cellular trafficking of prestin(NN163/166AA). These observations are the first to implicate a regulatory role for cellular trafficking and sorting in prestin function. We speculate that the cholesterol regulation of prestin occurs through localization to and internalization from membrane microdomains by
Cellular fiber–reinforced concrete
Isachenko S.; Kodzoev M.
2016-01-01
Methods disperse reinforcement of concrete matrix using polypropylene, glass, basalt and metal fibers allows to make the construction of complex configuration, solve the problem of frost products. Dispersed reinforcement reduces the overall weight of the structures. The fiber replaces the secondary reinforcement, reducing the volume of use of structural steel reinforcement. Cellular Fiber concretes are characterized by high-performance properties, especially increased bending strength and...
Identification of Nonstationary Cellular Automata
Institute of Scientific and Technical Information of China (English)
AndrewI.Adamatzky
1992-01-01
The principal feature of nonstationary cellular automata(NCA) is that a local transitiol rule of each cell is changed at each time step depending on neighborhood configuration at previous time step.The identification problem for NCA is extraction of local transition rules and the establishment of mechanism for changing these rules using sequence of NCA configurations.We present serial and parallel algorithms for identification of NCA.
CELLULAR INTERACTIONS MEDIATED BY GLYCONECTIDS
Popescu, O.; Sumanovski, L. T.; I. Checiu; Elisabeta Popescu; G. N. Misevic
1999-01-01
Cellular interactions involve many types of cell surface molecules and operate via homophilic and/or heterophilic protein-protein and protein-carbohydrate binding. Our investigations in different model-systems (marine invertebrates and mammals) have provided direct evidence that a novel class of primordial proteoglycans, named by us gliconectins, can mediate cell adhesion via a new alternative molecular mechanism of polyvalent carbohydrate-carbohydrate binding. Biochemical characterization of...
The insect cellular immune response
Institute of Scientific and Technical Information of China (English)
Michael R. Strand
2008-01-01
The innate immune system of insects is divided into humoral defenses that include the production of soluble effector molecules and cellular defenses like phagocytosis and encapsulation that are mediated by hemocytes. This review summarizes current understanding of the cellular immune response. Insects produce several terminally differentiated types of hemocytes that are distinguished by morphology, molecular and antigenic markers, and function. The differentiated hemocytes that circulate in larval or nymphal stage insects arise from two sources: progenitor cells produced during embryogenesis and mesodermally derived hematopoietic organs. Regulation of hematopoiesis and hemocyte differentiation also involves several different signaling pathways. Phagocytosis and encapsulation require that hemocytes first recognize a given target as foreign followed by activation of downstream signaling and effector responses. A number of humoral and cellular receptors have been identified that recognize different microbes and multicellular parasites. In turn, activation of these receptors stimulates a number of signaling pathways that regulate different hemocyte functions. Recent studies also identify hemocytes as important sources of a number of humoral effector molecules required for killing different foreign invaders.
Progress of cellular dedifferentiation research
Institute of Scientific and Technical Information of China (English)
LIU Hu-xian; HU Da-hai; JIA Chi-yu; FU Xiao-bing
2006-01-01
Differentiation, the stepwise specialization of cells, and transdifferentiation, the apparent switching of one cell type into another, capture much of the stem cell spotlight. But dedifferentiation, the developmental reversal of a cell before it reinvents itself, is an important process too. In multicellular organisms, cellular dedifferentiation is the major process underlying totipotency, regeneration and formation of new stem cell lineages. In humans,dedifferentiation is often associated with carcinogenesis.The study of cellular dedifferentiation in animals,particularly early events related to cell fate-switch and determination, is limited by the lack of a suitable,convenient experimental system. The classic example of dedifferentiation is limb and tail regeneration in urodele amphibians, such as salamanders. Recently, several investigators have shown that certain mammalian cell types can be induced to dedifferentiate to progenitor cells when stimulated with the appropriate signals or materials. These discoveries open the possibility that researchers might enhance the endogenous regenerative capacity of mammals by inducing cellular dedifferentiation in vivo.