[A Road Traffic CA Paper] - A New Kind of Science: The NKS ForumA New Kind of Science: The NKS Forum
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A Road Traffic CA Paper
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Posted by: Kovas Boguta
Here is a fairly recent paper about road traffic models that are related to CAs.
Non-concave fundamental diagrams and phase transitions in a stochastic traffic cellular automaton
Maerivoet, S. and B. De Moor.
http://arxiv.org/PS_cache/nlin/pdf/0404/0404018.pdf
Abstract: Within the class of stochastic cellular automata models of traffic flows, we look at the velocity dependent randomization variant (VDR-TCA) whose parameters take on a specific set of extreme values. We discover the emergence of four distinct phases and study the transitions between them, allowing us to establish a rigorous classification based on their tempo-spatial behavioral characteristics. As a result from the system's complex dynamics, its flow-density relation exhibits a non-concave region in which forward propagating density waves are encountered. All four phases furthermore share the common property that moving vehicles can never increase their speed once the system has settled into an equilibrium.
Posted by: Richard J. Gaylord
having constructed 'ca' models of traffic flow, and published on them and having extensively read the literature in the field, it should be noted that most of the workers in the field have no conception of what properly constitutes a CA. their models are certainly NOT cellular automata except in the sense of having objects (card) move on a lattice subject to various rules and constraints. that does not make them ca's.
this is roughly equivalent to studying the behavior of various 'life-forms' in the game of life ca.
i wonder what is the likely hood that if an investigator 'observed' the behavior of gliders would ever deduce that the glider is an epiphenomenon produced by rules about the turing off and on of cells.
it even makes me wonder if we can ever learn the 'laws of physics' by studying the behavior of physical objects. there is no compelling reason to think that these 'observables' are 'real' rather than simply behaviors based on rules that bear no direct resemblance (or connection) to observation. i believe stephen has very clearly pointed this out in NKS.
one could easily believe (at least i do) that searching for the laws of nature by studying the behavior of objects is fubndamentally misguided.
perhaps this has an equivalence to the long mis-guided attempt to study the mind rather than the brain?
Posted by: Sven Maerivoet
Hi,
let me take the opportunity to point you to a more recent paper, covering CA models for road traffic from a more behavioural point of view:
"Cellular Automata Models of Road Traffic"
Sven Maerivoet and Bart De Moor
Physics Reports, vol. 419, nr. 1, pages 1-64, november 2005
You can find it at http://phdsven.dyns.cx -> Publications -> Papers written.
With kind regards,
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dr. Sven Maerivoet
E-mail : sven.maerivoet@esat.kuleuven.be
Signals, Identification, System Theory and Automation (SISTA)
Department of Electrical Engineering (ESAT)
Katholieke Universiteit Leuven
Kasteelpark Arenberg 10
3001 Leuven (Heverlee) - Belgium
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Posted by: vantran
I can't download the TCA software - source code from the link.
May you send the source code for me.
vanthq@yahoo.com
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