Non-local interactions in spatial evolutionary games

As a special case of symmetric game in which the players share a common payoff matrix, evolutionary game provides a suitable approach to model and explore the emergence of cooperative behavior in natural and social systems. The evolutionary spatial game (ESG) further specifies the payoff for each individual by both the payoff matrix $M$ and the spatial dependence structure of the population on a geophysical domain. Two players game serves as a foundation of modeling various biological/social interactive systems and provides a great amount of interesting game theoretical models such as prisoner\u27s dilemma game, snow drift game etc. We formulate a two players evolutionary spatial game under the framework of initialization, effective local payoff, and the Markov chain for strategy update. The spatial dependence structure is modeled by a probability distribution parameterized by the dependence geometry and strength in the neighborhood of each location. Particularly, we study the structure based on Gaussian process. Computational methods are proposed and applied to study the convergence of simulations. In addition, limiting non-local differential equation is introduced and analysed in terms of spreading speeds and traveling waves

Deterministic Approximation of a Stochastic Imitation Dynamics with Memory

We provide results of a deterministic approximation for non-Markovian stochastic processes modeling finite populations of individuals who recurrently play symmetric finite games and imitate each other according to payoffs. We show that a system of delay differential equations can be obtained as the deterministic approximation of such a non-Markovian process. We also show that if the initial states of stochastic process and the corresponding deterministic model are close enough, then the trajectory of stochastic process stays close to that of the deterministic model up to any given finite time horizon with a probability exponentially approaching one as the population size increases. We use this result to obtain that the lower bound of the population size on the absorption time of the non-Markovian process is exponentially increasing. Additionally, we obtain the replicator equations with distributed and discrete delay terms as examples and analyze how the memory of individuals can affect the evolution of cooperation in a two-player symmetric Snow-drift game. We investigate the stability of the evolutionary stable state of the game when agents have the memory of past population states, and implications of these results are given for the stochastic model.Comment: 23 pages, 2 figures one of which includes 4 subfigure

O papel do conhecimento tácito na adesão às normas sociais

This paper aims to contribute to the ongoing discussion on adherence to social norms. It considers insights from multiple research traditions in an effort to explain how individual learning and action are connected to social norms. One strand of philosophical tradition holds that non-representational learning and skillful coping carried out unconsciously are underestimated by both scientific and philosophical traditions. The present research combines this tradition with the literature on the evolution of social norms and suggests that experienced individuals in a society adhere to social norms better than novice agents do. We explain this phenomenon by unconscious and non-representational cognitive processes. This framework is then used to investigate population-level outcomes of individual learning.Keywords: adherence to norms, expertise, skillful coping.Este artigo tem como objetivo contribuir para a discussão em curso sobre a adesão às normas sociais. Ele cosnidera insights de múltiplas tradições de pesquisa em um esforço para explicar como a aprendizagem e a ação individuais estão conectadas às normas sociais. Uma vertente da tradição filosófica sustenta que a aprendizagem não representacional e o enfrentamento hábil inconscientemente são subestimados pelas tradições científicas e filosóficas. A presente pesquisa combina esta tradição com a literatura sobre a evolução das normas sociais e sugere que os indivíduos experientes em uma sociedade adiram às normas sociais melhor do que os agentes novatos. Explicamos este fenômeno por processos cognitivos inconscientes e não representativos. Este quadro é então utilizado para investigar resultados de nível individual da aprendizagem individual.Palavras-chave: aderência às normas, perícia, habilidades de enfrentamento

Non-local interactions in spatial evolutionary games

As a special case of symmetric game in which the players share a common payoff matrix, evolutionary game provides a suitable approach to model and explore the emergence of cooperative behavior in natural and social systems. The evolutionary spatial game (ESG) further specifies the payoff for each individual by both the payoff matrix $M$ and the spatial dependence structure of the population on a geophysical domain. Two players game serves as a foundation of modeling various biological/social interactive systems and provides a great amount of interesting game theoretical models such as prisoner's dilemma game, snow drift game etc. We formulate a two players evolutionary spatial game under the framework of initialization, effective local payoff, and the Markov chain for strategy update. The spatial dependence structure is modeled by a probability distribution parameterized by the dependence geometry and strength in the neighborhood of each location. Particularly, we study the structure based on Gaussian process. Computational methods are proposed and applied to study the convergence of simulations. In addition, limiting non-local differential equation is introduced and analysed in terms of spreading speeds and traveling waves.</p

Determination of ascorbic acid in vegetables by derivative spectrophotometry

Determination of ascorbic acid (AA) in garlic, green pepper and chestnut was performed by derivative spectrophotometry without using any pre-separation or background correction techniques. The method is based on the measurement of the distances between two extremum values (peak-to-peak amplitudes) in second and third order derivative spectra of the extracts. Ten percent trichloroacetic acid was found to be the most suitable extraction solution. In the second order derivative spectrum the extrema of 253.2 and 259 nm for garlic, and in the third order derivative spectrum, the extrama of 256.4 and 261.6 nm for green pepper and chestrut samples were used for the determination of AA

Design of a low-power, low-cost UHF RFID reader module

A new low-power, low-cost ultrahigh-frequency (UHF) radio frequency identification (RFID) reader module for short range low/mid-powered applications is presented in this paper. AS3993 is used as the reader IC, which integrates all building blocks including an analog front-end, a microcontroller unit interface, a voltage-controlled oscillator, and a phase-locked loop in a 48-pin QFN (7 x 7 x 0.9 mm) package. It has a new architecture for lowering the power consumption with a DC supply of 2.7 V and a current of 65 mA, and improved AO dBm sensitivity. A power amplifier with medium power and high efficiency is also integrated to fulfill the function of the UHF RFID reader module. The reader module fully supports EPC Class 1 Gen2 ISO 18000-6C protocol and IS029143 air interface for mobile RFID. With the use of the AS3993 reader IC it is possible to reduce the total cost. This paper describes all the hardware and software designs and experimental results of the designed system. The measurement results indicate that the set output power value in the chip is achieved quite successfully

In-situ spark plasma sintering behavior of La2O3–Y2O3 co-doped AlON ceramics: An attempt to prevent carbon contamination

Un-doped and La2O3–Y2O3 co-doped Aluminum oxynitride (AlON) ceramics were fabricated by reactive spark plasma sintering method (R–SPS) by using Al2O3 and AlN as starting powders with a composition of 70 mol% and 30 mol%, respectively. The effects of co-doping system on densification, microstructure, mechanical properties and optical transmittance of AlON ceramics were investigated. X-ray analysis confirmed the fully transformation of γ-AlON phase for all compositions prepared at 1650 °C in 30 min under 40 MPa under nitrogen. The results indicated that 0.02 wt% La2O3+0.08 wt% Y2O3 added composition had the optimal combination of sintering additives. In an attempt to reduce the graphite contamination, the powder mixture was encapsulated in a Nb-coated graphite foil before subjecting to SPS. Nb-coated graphite foil encapsulated sample was found to reduce carbon contamination leading to high densification (99.6 %) and high transmission (∼81 % at 2500 nm). This study demonstrated that optical transmittance of R-SPSed AlON ceramics is significantly improved without any post-heat treatment by using Nb-coated graphite foil during SPS processing

Moran-type bounds for the fixation probability in a frequency-dependent Wright–Fisher model

We study stochastic evolutionary game dynamics in a population of finite size. Individuals in the population are divided into two dynamically evolving groups. The structure of the population is formally described by a Wright–Fisher type Markov chain with a frequency dependent fitness. In a strong selection regime that favors one of the two groups, we obtain qualitatively matching lower and upper bounds for the fixation probability of the advantageous population. In the infinite population limit we obtain an exact result showing that a single advantageous mutant can invade an infinite population with a positive probability. We also give asymptotically sharp bounds for the fixation time distribution.ISSN:1432-1416ISSN:0303-681