Cellular Automata

Complexity and Information: Measuring Emergence, Self-organization, and Homeostasis at Multiple Scales

by Nelson Fernández

Co-authored with Carlos Gershenson. Submitted to Complexity.

Concepts used in the scientific study of complex systems have become so widespread that their use and abuse has led to... more Concepts used in the scientific study of complex systems have become so widespread that their use and abuse has led to ambiguity and confusion in their meaning. In this paper we use information theory to provide abstract and concise measures of complexity, emergence, self-organization, and homeostasis. The purpose is to clarify the meaning of these concepts with the aid of the proposed formal measures. In a simplified version of the measures (focussing on the information produced by a system), emergence becomes the opposite of self-organization, while complexity represents their balance. We use computational experiments on random Boolean networks and elementary cellular automata to illustrate our measures at multiple scales.

Come ti Sconfiggo l’Entropia Informazionale: Automi Cellulari e Computazione Reversibile

by Jacopo Tagliabue

Co-authored with Francesco Berto and Gabriele Rossi. Published in 'Sistemi Intelligenti' (February 2012).

Cellular Automata

by Jacopo Tagliabue

Co-authored with Francesco Berto. Published in the Stanford Encyclopedia of Philosophy (April 2012).

A sketch-based system for highway design with user-specified regions of influence

by Christopher Applegate

Authors: C. S. Applegate, S. D. Laycock and A. M. Day. Published in: Computers & Graphics, Volume 36, Issue 6, October 2012, Pages 685-695, ISSN 0097-8493, 10.1016/j.cag.2012.03.033.

Paper:
- http://dx.doi.org/10.1016/j.cag.2012.03.033

Video:
- http://youtu.be/CrFHVncLKos

To create traffic simulations of high visual-fidelity, each component part needs to be designed and modelled in great... more To create traffic simulations of high visual-fidelity, each component part needs to be designed and modelled in great detail. Roads can be created manually, but this can become a time-consuming and laborious process when modelling large-scale networks. Therefore, automated techniques for generating road networks efficiently and effectively, is highly desirable in both urban-planning and entertainment industries. In this paper we present a novel sketch-based tool to semi-automate the design, creation, and visualisation of road networks across both flat and undulating terrains. Our tool is guided by input sketches and a combination of prioritised constraints, including the curvature of roads, their inclination, and the volume of ground that would be displaced during construction. We introduce ‘Influence Regions’ which are user-specified areas of the terrain that influence the path of the roads generated, and are used to attract or repel roads to/from certain obstacles or designated areas, such as forestation, listed buildings, marshland, etc. A user study is conducted to evaluate the usability of the system and the quality of roads generated in a diverse range of scenarios. The results indicate that our system is both user-friendly and able to produce roads that are true to the user's intention.

Porting and optimizing MAGFLOW on CUDA

by Giuseppe Bilotta

The MAGFLOW lava simulation model is a cellular automaton developed by the Sezione di Catania of the Istituto... more The MAGFLOW lava simulation model is a cellular automaton developed by the Sezione di Catania of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and it represents the peak of the evolution of cell-based models for lava-flow simulation. The accuracy and adherence to reality achieved by the physics-based cell evolution of MAGFLOW comes at the cost of significant computational times for long-running simulations. The present study describes the efforts and results obtained by porting the original serial code to the parallel computational platforms offered by modern video cards, and in particular to the NVIDIA Compute Unified Device Architecture (CUDA). A number of optimization strategies that have been used to achieve optimal performance on a graphic processing units (GPU) are also discussed. The actual benefits of running on the GPU rather than the central processing unit depends on the extent and duration of the simulated event; for large, long-running simulations, the GPU can be 70-to-80-times faster, while for short-lived eruptions with a small extents the speed improvements obtained are 40-to-50 times.

Scalable multi-GPU implementation of the MAGFLOW simulator

by Giuseppe Bilotta

We have developed a robust and scalable multi-GPU (Graphics Processing Unit) version of the cellular-automaton-based... more 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.

Lattice Gases with Static Disorder: Renormalization of Mean Field Theory

by Mathieu Ossendrijver

M. Ossendrijver, A. Santos, M.H. Ernst, J. Stat. Phys. 71, 1015-1042 (1993)

Energy-Aware Scheduling of Distributed Systems Using Cellular Automata

by Shrisha Rao

6th Annual IEEE International Systems Conference (IEEE SysCon 2012), Vancouver, Canada, March 2012.

In today’s world of large distributed systems, the need for energy efficiency of individual components is comple-... more In today’s world of large distributed systems, the need for energy efficiency of individual components is comple- mented by the need for energy awareness of the complete system. Hence, energy-aware scheduling of tasks on systems has become very important. Our work addresses the problem of finding an energy-aware schedule for a given system which also satisfies the precedence constraints between tasks to be performed by the system. We present a method which uses cellular automata to find a near-optimal schedule for the system. The rules for cellular automata are learned using a genetic algorithm. Though the work presented in this paper is not limited to scheduling in computing environments only, the work is validated with a sample simulation on distributed computing systems, and tested with some standard program graphs.

A Cellular Automata Model Can Quickly Approximate UDP and TCP Network Traffic

by Christopher Griffin

COMPLEX BEHAVIOR IN DYNAMICAL SYSTEMS

by Edmund Brekke

A Susceptible-Infected Model for Exploring the Effects of Neighborhood Structures on Epidemic Processes – A Segregation Analysis

by Leonardo Santos

Leonardo Bacelar Lima Santos, Raian Vargas Maretto,
Líliam César de Castro Medeiros, Flávia da Fonseca Feitosa,
Antônio Miguel Vieira Monteiro

This work explores and analyzes the effects of neighborhood structures on disease spreading in a compartmental... more This work explores and analyzes the effects of neighborhood structures on disease spreading in a compartmental epidemic CA-model. The main goal is to investigate how different neighborhood configurations are able to affect the spatial and temporal distribution of infected and susceptible individuals
and the chance of having members from these different groups interacting with each other. It uses the idea of “activity-space neighborhood”, which extends traditional contiguity-based neighborhoods to capture interactions beyond those
established in a residential environment. To depict the spatial distribution of infected and susceptible individuals along the simulation steps, we introduce the use of spatial segregation indices, traditionally adopted in urban studies, to an
epidemiological context.

Concepts, methodologies, and tools of an integrated geographical simulation and optimization system

by Yimin Chen

Authors: Li Xia, Chen Yimin, Liu Xiaoping, Li Dan and He Jinqiang. Published in International Journal of Geographical Information Science, 2011

Although being increasingly powerful in handling spatial data, geographical information systems (GIS) still lack the... more Although being increasingly powerful in handling spatial data, geographical information systems (GIS) still lack the powerful functionality for process modeling in terms of simulation and optimization. This article discusses the concepts and methodologies of a geographical simulation and optimization system (GeoSOS). GeoSOS integrates cellular automata (CA), agent-based models (ABMs), and swarm intelligence models (SIMs) for solving process simulation and optimization problems. A general form of the so-called interaction rules is proposed for implementing this integrated system. The GeoSOS software is developed to provide these complementary functions that are unavailable in the current GIS. Experiments have demonstrated that GeoSOS is able to model the reciprocal relationships between urban simulation and spatial optimization (e.g., facility sitting, transport development, and natural protection) in fast-growing regions. Better modeling performances have been achieved using the coupling strategies of GeoSOS.

Failover in Cellular Automata

by Shrisha Rao

Co-authored with Shailesh Kumar. Physics Procedia (Elsevier), vol. 22, 2011, pp. 557--564. doi:10.1016/j.phpro.2011.11.086

This paper studies a phenomenon called failover, and shows that this phenomenon (in particular, stateless failover)... more This paper studies a phenomenon called failover, and shows that this phenomenon (in particular, stateless failover) can be modeled by Game of Life cellular automata. This is the first time that this sophisticated real-life system behavior has been modeled in abstract terms. 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 the 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.

Disorder, memory and avalanches in sandpiles

by Anita Mehta

Avalanches at rough surfaces

by Anita Mehta

Fractal replication in time-manipulated one-dimensional cellular automata

by Sujai Kumar

On making music with artificial life models

by Prof Eduardo R. Miranda

A Proposed Pedestrian Waiting-Time Model for Improving Space-Time Use Efficiency in Stadium Evacuation Scenarios

by Lee D. Han

Building and Environment (2011) 46:1774-1784
with Zhixiang FANG, Qingquan LI, Qiuping LI, and Dan WANG

Efficiency is a fundamental requirement in evacuation planning and operations. The “faster-is-slower” phenomenon in... more Efficiency is a fundamental requirement in evacuation planning and operations. The “faster-is-slower” phenomenon in pedestrian evacuation has been observed and deemed a significant obstacle to evacuation efficiency. This paper thus focuses on two aspects of evacuation planning in the case of stadium evacuation. The first is to define a space–time use efficiency measure for evaluating the utility of both space and time resources. The second is to propose a pedestrian waiting-time model for directing evacuees to alleviate evacuation bottlenecks.

An agent-based simulation approach was employed to test the proposed model in stadium evacuation scenarios. The results demonstrate that compelled, or mandatory, waiting time strategy generated by this model is helpful in improving the space–time use efficiency of network links in the evacuation process by virtue of the strategically timed moving-waiting-restarting movement pattern of evacuees. The analysis of space–time evacuation paths in this study provides a practical and insightful alternative for measuring evacuation effectiveness.

Results of this study compared reasonably against an existing cellular automata based simulation both in microscopic and macroscopic perspectives. A number of future research directions were presented.

Art, digitality and consciousness

by Guy Birkin

Birkin, G., (2005). Art, Digitality and Consciousness. In: Proceedings of the 5th Conference on Creativity and Cognition, Goldsmiths College, London, 12–15 April 2005. pp. 279–282.

This paper is intended as an accompaniment to digital artworks*, and forms a concise outline of the practical and... more This paper is intended as an accompaniment to digital artworks*, and forms a concise outline of the practical and theoretical elements of my research into digital processes.
It begins by describing the processes used to create the artworks, then the scientific paradigm shift from which these processes are derived. This new kind of science begins with or leads to the question, ‘What if space and time are digital?’ My research prompted a reassessment of the meaning of ‘digital’, which in turn re-defined the potential ‘digital media’ and, therefore, what may be called ‘digital art’.
Lastly, it is shown that this new science relates to the older field of Process Philosophy. That these fields share an emphasis on the importance of the concepts of time, change and process can be seen as supporting evidence for Jean Gebser’s model of evolutionary consciousness. This model enables cohesion of the scientific ideas and is the context in which the artworks were conceived.

* exhibited at the 5th Conference on Creativity and Cognition, Goldsmiths College, London, 12–15 April 2005

Real-Time Traffic Simulation Using Cellular Automata

by Christopher Applegate

Authors: C. S. Applegate, S. D. Laycock and A. M. Day. Published in EG UK Theory and Practice of Computer Graphics, Sheffield, UK, pp 91-98, September 2010.

The definitive version is available at diglib.eg.org:
http://dx.doi.org/10.2312/LocalChapterEvents/TPCG/TPCG10/091-098

In this paper, we present a method to simulate large-scale traffic networks, at real-time frame-rates. Our novel... more In this paper, we present a method to simulate large-scale traffic networks, at real-time frame-rates. Our novel contributions include a method to automatically generate a road graph from real-life data, and our extension to a discrete traffic model, which we use to simulate traffic, demonstrating continuous vehicle motion between discrete locations. Given Ordnance Survey data, we automatically generate a road graph, identifying roads, junctions, and their connections. We distribute cells at regular intervals throughout the graph, which are used as discrete vehicle locations in our traffic model. Vehicle positions are then interpolated between cells to obtain continuous animation. We test the performance of our model using a 500 x 500m2 area of a real city, and demonstrate that our model can simulate over 600 vehicles at real-time frame-rates (>80% network density).