Statistical Mechanics of Dilute Batch Minority Games with Random External Information

We study the dynamics and statics of a dilute batch minority game with random external information. We focus on the case in which the number of connections per agent is infinite in the thermodynamic limit. The dynamical scenario of ergodicity breaking in this model is different from the phase transition in the standard minority game and is characterised by the onset of long-term memory at finite integrated response. We demonstrate that finite memory appears at the AT-line obtained from the corresponding replica calculation, and compare the behaviour of the dilute model with the minority game with market impact correction, which is known to exhibit similar features.Comment: 22 pages, 6 figures, text modified, references updated and added, figure added, typos correcte

Using Strategy Improvement to Stay Alive

We design a novel algorithm for solving Mean-Payoff Games (MPGs). Besides solving an MPG in the usual sense, our algorithm computes more information about the game, information that is important with respect to applications. The weights of the edges of an MPG can be thought of as a gained/consumed energy -- depending on the sign. For each vertex, our algorithm computes the minimum amount of initial energy that is sufficient for player Max to ensure that in a play starting from the vertex, the energy level never goes below zero. Our algorithm is not the first algorithm that computes the minimum sufficient initial energies, but according to our experimental study it is the fastest algorithm that computes them. The reason is that it utilizes the strategy improvement technique which is very efficient in practice

Solving Optimization Problems by the Public Goods Game

This document is the Accepted Manuscript version of the following article: Marco Alberto Javarone, ‘Solving optimization problems by the public goods game’, The European Physical Journal B, 90:17, September 2017. Under embargo. Embargo end date: 18 September 2018. The final, published version is available online at doi: https://doi.org/10.1140/epjb/e2017-80346-6. Published by Springer Berlin Heidelberg.We introduce a method based on the Public Goods Game for solving optimization tasks. In particular, we focus on the Traveling Salesman Problem, i.e. a NP-hard problem whose search space exponentially grows increasing the number of cities. The proposed method considers a population whose agents are provided with a random solution to the given problem. In doing so, agents interact by playing the Public Goods Game using the fitness of their solution as currency of the game. Notably, agents with better solutions provide higher contributions, while those with lower ones tend to imitate the solution of richer agents for increasing their fitness. Numerical simulations show that the proposed method allows to compute exact solutions, and suboptimal ones, in the considered search spaces. As result, beyond to propose a new heuristic for combinatorial optimization problems, our work aims to highlight the potentiality of evolutionary game theory beyond its current horizons.Peer reviewedFinal Accepted Versio

Definitions, measurement and prevalence of sedentary behaviour in adults with intellectual disabilities – a systematic review

Supporting positive change in lifestyle behaviours is a priority in tackling the health inequalities experienced by adults with intellectual disabilities. In this systematic review, we examine the evidence on the definition, measurement and epidemiology of sedentary behaviour of adults with intellectual disabilities. A systematic literature search of PUBMED, EMBASE, MEDLINE and Google Scholar was performed to identify studies published from 1990 up to October 2015. Nineteen papers met the criteria for inclusion in the systematic review. Many researchers do not distinguish between insufficient physical activity and sedentary behaviour. None of the studies reported the reliability and validity of the methods used to measure sedentary behaviour. Sedentary time, assessed objectively, ranged from 522 to 643 min/day: higher than in adults without intellectual disabilities. This first-ever review of sedentary behaviour and intellectual disabilities found that at present the evidence base is weak. Studies calibrating accelerometer data with criterion measures for sedentary behaviour are needed to determine specific cut-off points to measure sedentary behaviour in adults with intellectual disabilities. Researchers should also examine the reliability and validity of using proxy-report questionnaires to measure sedentary behaviour in this group. A better understanding of sedentary behaviour will inform the design of novel interventions to change lifestyle behaviours of adults with intellectual disabilities