scholarly journals Evolution of Cooperation with Moore Neighborhood and Self-Playing Rule

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Yanbing Yang ◽  
Junhu Ruan ◽  
Bin Liu ◽  
Yi Liu ◽  
Yan Shi
Keyword(s):  
Evolution Of Cooperation ◽  
Critical Conditions ◽  
Initial Population ◽  
Spatial Structures ◽  
Von Neumann ◽  
Lattice Size ◽  
Innovative Method ◽  
Moore Neighborhood ◽  
Spatial Game ◽  
New Evidence

Evolutionary spatial game is a promising way to unravel the mystery of cooperation, and it has been well recognized that spatial structure could enable cooperation to persist. Schweitzer et al.’s lattice model provides an innovative method to solve the problem. In this paper, we conduct simulations using the same von Neumann neighborhood as in Schweitzer et al.’s study (2002) and observe the effect of initial population and lattice size on the evolution of cooperation. Then, we extend the model with a more complicated Moore neighborhood and self-playing rule for each central player. Simulation results not only provide new evidence for the persistence of cooperation in the evolution with spatial structures, but also investigate critical conditions for the spatial coexistence or the invasion of cooperators and defectors with the more complicated neighborhood.

EFFECTS OF SPACE IN 2 × 2 GAMES

2002 ◽  
Vol 12 (07) ◽  
pp. 1531-1548 ◽  
Author(s):  
CH. HAUERT
Keyword(s):  
Cooperative Behavior ◽  
Mean Field ◽  
Systematic Analysis ◽  
Von Neumann ◽  
Spatial Extension ◽  
Moore Neighborhood ◽  
The Mean ◽  
Mixed Populations ◽  
Update Rules ◽  
Rectangular Lattices

A systematic analysis of the effects of spatial extension on the equilibrium frequency of cooperators and defectors in 2 × 2 games is presented and compared to well mixed populations where spatial extension can be neglected. We demonstrate that often spatial extension is indeed capable of promoting cooperative behavior. This holds in particular for the prisoner's dilemma for a small but important parameter range. For the hawk–dove game, spatial extension may lead to both, increases of the hawk- as well as the dove-strategy. The outcome subtly depends on the parameters as well as on the degree of stochasticity in the different update rules. For rectangular lattices, the general conclusions are rather robust and hold for different neighborhood types i.e. for the von Neumann as well as the Moore neighborhood and, in addition, they appear to be almost independent of the update rule of the lattice. However, increasing stochasticity for the update rules of the players results in equilibrium frequencies more closely related to the mean field description.

scholarly journals On the analysis of ''simple'' 2D stochastic cellular automata

2010 ◽  
Vol Vol. 12 no. 2 ◽  
Author(s):  
Damien Regnault ◽  
Nicolas Schabanel ◽  
Eric Thierry
Keyword(s):  
Cellular Automata ◽  
Time Step ◽  
Energy Functions ◽  
Stochastic Cellular Automata ◽  
Von Neumann ◽  
Rich Variety ◽  
Moore Neighborhood ◽  
International Audience ◽  
Definition Of ◽  
New Phenomena

International audience Cellular automata are usually associated with synchronous deterministic dynamics, and their asynchronous or stochastic versions have been far less studied although significant for modeling purposes. This paper analyzes the dynamics of a two-dimensional cellular automaton, 2D Minority, for the Moore neighborhood (eight closest neighbors of each cell) under fully asynchronous dynamics (where one single random cell updates at each time step). 2D Minority may appear as a simple rule, but It is known from the experience of Ising models and Hopfield nets that 2D models with negative feedback are hard to study. This automaton actually presents a rich variety of behaviors, even more complex that what has been observed and analyzed in a previous work on 2D Minority for the von Neumann neighborhood (four neighbors to each cell) (2007) This paper confirms the relevance of the later approach (definition of energy functions and identification of competing regions) Switching to the Moot e neighborhood however strongly complicates the description of intermediate configurations. New phenomena appear (particles, wider range of stable configurations) Nevertheless our methods allow to analyze different stages of the dynamics It suggests that predicting the behavior of this automaton although difficult is possible, opening the way to the analysis of the whole class of totalistic automata

scholarly journals EVOLUTION OF COOPERATION IN A SPATIAL PRISONER'S DILEMMA

2002 ◽  
Vol 05 (02n03) ◽  
pp. 269-299 ◽  
Author(s):  
FRANK SCHWEITZER ◽  
LAXMIDHAR BEHERA ◽  
HEINZ MÜHLENBEIN
Keyword(s):  
Prisoner's Dilemma ◽  
Prisoner’S Dilemma ◽  
Evolution Of Cooperation ◽  
Critical Conditions ◽  
Agent Interaction ◽  
Spatial Domains ◽  
Simulation Results ◽  
Person Game ◽  
Small Clusters ◽  
Spatial Prisoner’S Dilemma

We investigate the spatial distribution and the global frequency of agents who can either cooperate or defect. The agent interaction is described by a deterministic, non-iterated prisoner's dilemma game, further each agent only locally interacts with his neighbors. Based on a detailed analysis of the local payoff structures we derive critical conditions for the invasion or the spatial coexistence of cooperators and defectors. These results are concluded in a phase diagram that allows us to identify five regimes, each characterized by a distinct spatiotemporal dynamics and a corresponding final spatial structure. In addition to the complete invasion of defectors, we find coexistence regimes with either a majority of cooperators in large spatial domains, or a minority of cooperators organized in small non-stationary domains or in small clusters. The analysis further allowed a verification of computer simulation results by Nowak and May (1993). Eventually, we present simulation results of a true 5-person game on a lattice. This modification leads to non-uniform spatial interactions that may even enhance the effect of cooperation.

scholarly journals Spatial reciprocity in the evolution of cooperation

2019 ◽  
Vol 286 (1900) ◽  
pp. 20190041 ◽  
Author(s):  
Qi Su ◽  
Aming Li ◽  
Long Wang ◽  
H. Eugene Stanley
Keyword(s):  
Spatial Structure ◽  
Role Models ◽  
Role Model ◽  
Social Ties ◽  
Analytical Formula ◽  
Evolution Of Cooperation ◽  
Spatial Structures ◽  
Group Interactions ◽  
Interaction Partners ◽  
Model Understanding

Cooperation is key to the survival of all biological systems. The spatial structure of a system constrains who interacts with whom (interaction partner) and who acquires new traits from whom (role model). Understanding when and to what degree a spatial structure affects the evolution of cooperation is an important and challenging topic. Here, we provide an analytical formula to predict when natural selection favours cooperation where the effects of a spatial structure are described by a single parameter. We find that a spatial structure promotes cooperation (spatial reciprocity) when interaction partners overlap role models. When they do not, spatial structure inhibits cooperation even without cooperation dilemmas. Furthermore, a spatial structure in which individuals interact with their role models more often shows stronger reciprocity. Thus, imitating individuals with frequent interactions facilitates cooperation. Our findings are applicable to both pairwise and group interactions and show that strong social ties might hinder, while asymmetric spatial structures for interaction and trait dispersal could promote cooperation.

scholarly journals Predator–prey pattern formation driven by population diffusion based on Moore neighborhood structure

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Tousheng Huang ◽  
Huayong Zhang ◽  
Zhengran Hu ◽  
Ge Pan ◽  
Shengnan Ma ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Turing Instability ◽  
Global Dynamics ◽  
Neighborhood Structure ◽  
Von Neumann ◽  
Predator Prey ◽  
System A ◽  
Self Organized ◽  
Moore Neighborhood ◽  
The Way

Abstract Diffusion-driven instability is a basic nonlinear mechanism for pattern formation. Therefore, the way of population diffusion may play a determinative role in the spatiotemporal dynamics of biological systems. In this research, we launch an investigation on the pattern formation of a discrete predator–prey system where the population diffusion is based on the Moore neighborhood structure instead of the von Neumann neighborhood structure widely applied previously. Under pattern formation conditions which are determined by Turing instability analysis, numerical simulations are performed to reveal the spatiotemporal complexity of the system. A pure Turing instability can induce the self-organization of many basic types of patterns as described in the literature, as well as new spiral-spot and labyrinth patterns which show the temporally oscillating and chaotic property. Neimark–Sacker–Turing and flip–Turing instability can lead to the formation of circle, spiral and much more complex patterns, which are self-organized via spatial symmetry breaking on the states that are homogeneous in space and non-periodic in time. Especially, the emergence of spiral pattern suggests that spatial order can generate from temporal disorder, implying that even when the predator–prey dynamics in one site is chaotic, the spatially global dynamics may still be predictable. The results obtained in this research suggest that when the way of population diffusion changes, the pattern formation in the predator–prey systems demonstrates great differences. This may provide realistic significance to explain more general predator–prey coexistence.

Systematic effects in observed parallaxes

1978 ◽  
Vol 48 ◽  
pp. 31-35
Author(s):  
R. B. Hanson
Keyword(s):  
Error Estimates ◽  
Zero Point ◽  
Absolute Zero ◽  
Apparent Magnitude ◽  
Coherent System ◽  
Preliminary Results ◽  
General Catalogue ◽  
Systematic Effects ◽  
New Evidence ◽  
Right Ascension

Several outstanding problems affecting the existing parallaxes should be resolved to form a coherent system for the new General Catalogue proposed by van Altena, as well as to improve luminosity calibrations and other parallax applications. Lutz has reviewed several of these problems, such as: (A) systematic differences between observatories, (B) external error estimates, (C) the absolute zero point, and (D) systematic observational effects (in right ascension, declination, apparent magnitude, etc.). Here we explore the use of cluster and spectroscopic parallaxes, and the distributions of observed parallaxes, to bring new evidence to bear on these classic problems. Several preliminary results have been obtained.

MERLIN Finds New Evidence of Ranolazine Safety

2007 ◽  
Vol 40 (9) ◽  
pp. 36
Author(s):  
BRUCE JANCIN
Keyword(s):  
New Evidence

Lectures on von Neumann Algebras

2019 ◽  
Author(s):  
Serban-Valentin Stratila ◽  
Laszlo Zsido
Keyword(s):  
Von Neumann Algebras ◽  
Von Neumann

Vaccination for travellers – new evidence and recommendations

2001 ◽  
Vol 58 (6) ◽  
pp. 362-366 ◽  
Author(s):  
Matius P. Stürchler ◽  
R. P. Steffen
Keyword(s):  
Hepatitis B ◽  
Hepatitis A ◽  
New Evidence

Impfungen sind einfache und effektive Maßnahmen zur Verhinderung von Reisekrankheiten. Compliance-Probleme sind gering, da alle Impfungen noch vor Abreise verabreicht werden und bei manchen Impfungen nur eine Dosis für den zuverlässigen Schutz nötig ist. Für jeden Reisenden sind die Hepatitis A- und die Diphtherie-Tetanus-Impfung empfohlen, für Asien und Afrika auch die Polioimpfung. Bei Reisen >30 Tagen, jüngeren Personen und Reisenden mit Risikoverhalten sollte immer auch eine Hepatitis B-Impfung, eventuell als Kombination mit Hepatitis A in Betracht gezogen werden. Je nach Reisestil, -destination und -dauer können auch weitere Impfungen wie z.B. die Typhus-, Tollwut-, Zeckenenzephalitis-, Grippe-, Masern-Mumps-Röteln-, Gelbfieber-, Meningokokkenmeningitis- und die Japanische Enzephalitis-Impfung in Frage kommen. Mehrere Impfungen können gleichzeitig verabreicht werden – eine Staffelung ist nicht nötig. i BAG Supplementum VI, Stand Juli 2000 «Impfungen für Auslandreisende»; http://www.admin.ch/bag/infekt/prev/reisemed/index.htm; Safetravel http://www.safetravel.ch; Tropimed

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