記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.amc.2016.11.036

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1209/0295-5075/116/38005

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1088/1742-5468/2016/09/093501

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.physa.2016.04.023

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1103/PhysRevE.94.022114

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.physa.2016.06.002

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Why would natural selection favor the prevalence of cooperation within the groups of selfish individuals? A fruitful framework to address this question is evolutionary game theory, the essence of which is captured in the so-called social dilemmas. Such dilemmas have sparked the development of a variety of mathematical approaches to assess the conditions under which cooperation evolves. Furthermore, borrowing from statistical physics and network science, the research of the evolutionary game dynamics has been enriched with phenomena such as pattern formation, equilibrium selection, and self-organization. Numerous advances in understanding the evolution of cooperative behavior over the last few decades have recently been distilled into five reciprocity mechanisms: direct reciprocity, indirect reciprocity, kin selection, group selection, and network reciprocity. However, when social viscosity is introduced into a population via any of the reciprocity mechanisms, the existing scaling parameters for the dilemma strength do not yield a unique answer as to how the evolutionary dynamics should unfold. Motivated by this problem, we review the developments that led to the present state of affairs, highlight the accompanying pitfalls, and propose new universal scaling parameters for the dilemma strength. We prove universality by showing that the conditions for an ESS and the expressions for the internal equilibriums in an infinite, well-mixed population subjected to any of the five reciprocity mechanisms depend only on the new scaling parameters. A similar result is shown to hold for the fixation probability of the different strategies in a finite, well-mixed population. Furthermore, by means of numerical simulations, the same scaling parameters are shown to be effective even if the evolution of cooperation is considered on the spatial networks (with the exception of highly heterogeneous setups). We close the discussion by suggesting promising directions for future research including (i) how to handle the dilemma strength in the context of co-evolution and (ii) where to seek opportunities for applying the game theoretical approach with meaningful impact.

DOI： http://dx.doi.org/10.1016/j.plrev.2015.04.033

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.chaos.2015.04.018

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.amc.2015.03.018

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.chaos.2015.03.021

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1142/S0129183115500722

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1103/PhysRevE.91.042106

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.chaos.2015.02.025

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1088/1742-5468/2015/01/P01033

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://iopscience.iop.org/1742-5468/2014/12/P12024/

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://iopscience.iop.org/1742-5468/2014/11/P11010/

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1088/1742-5468/2014/11/P11027

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.chaos.2014.07.004

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.4236/jamp.2014.27076

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://link.aps.org/doi/10.1103/PhysRevE.90.022105

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/ 10.1088/1742-5468/2014/07/P07019

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1088/1742-5468/2014/05/P05003

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1103/PhysRevE.89.012106

その他リンク： http://dx.doi.org/10.1103/PhysRevE.89.012106

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://link.aps.org/doi/10.1103/PhysRevE.88.062149

その他リンク： http://link.aps.org/doi/10.1103/PhysRevE.88.062149

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.chaos.2013.05.007

その他リンク： http://dx.doi.org/10.1016/j.chaos.2013.05.007

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1371/journal.pone.0076942

その他リンク： http://dx.doi.org/10.1371/journal.pone.0076942

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.chaos.2013.07.00

その他リンク： http://dx.doi.org/10.1016/j.chaos.2013.07.00

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1103/PhysRevE.88.042145

その他リンク： http://dx.doi.org/10.1103/PhysRevE.88.042145

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1371/journal.pone.0071961

その他リンク： http://dx.doi.org/10.1371/journal.pone.0071961

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.physa.2013.02.004

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://link.aps.org/doi/10.1103/PhysRevE.87.062136

その他リンク： http://link.aps.org/doi/10.1103/PhysRevE.87.062136

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://link.aps.org/doi/10.1103/PhysRevE.86.031141

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.biosystems.2011.10.001

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.jweia.2012.02.008

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Our previous study (Tanimoto & Hagishima (2005), Energy and Buildings) proposed a set of state transition probabilities for the Markov chain dealing with the on/off cooling schedule in dwellings. The probability of turning on an air conditioner was defined in the form of a sigmoid function by the indoor globe temperature. Obviously, a real stochastic event of shifting from the off to on state is affected by not only indoor thermal quality parameters but also other complex factors such as the presence of family members, time of the day, and whether it is a weekday or holiday. In this paper, we report an alternate model, based on a multilayered artificial neural network (MANN), for predicting the off to on cooling schedule. We gathered field measurement data on family dwellings during the summer of 2008 by deploying hygrothermometers with recording functions to measure the room temperature and the globe and blowout air temperature of the air conditioner. The MANN used has nine nodes in both its input and hidden layers and a single node in its output layer, which implies that the state is either shifting from off to on (1) or not (0). The information provided to the input layer nodes includes the time of the day, whether it is a weekday or holiday, the probability of the presence of inhabitants, and the predicted percentage of dissatisfied people (PPD). PPD, derived from PMV theory, is applied as a representative parameter of the indoor thermal quality, in place of the globe temperature, since it accounts for various influences. The field measurement datasets were divided into two parts: teaching data and data for validation. A model trained by the teaching data was confirmed to reproduce the state transition characteristic of the validation period, which seems complex and is determined by the behavior of various inhabitants. The performance of the model in reproducing this behavior is improved over that of the previous model derived from the Markov chain.

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1142/S0129183111016749

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s10546-010-9551-7.

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.biosystems.2010.10.009

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.physa.2010.10.027

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.biosystems.2010.10.006

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.physa.2010.08.032

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.physa.2010.08.005

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.biosystems.2010.07.017

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.physa.2010.03.020

その他リンク： http://dx.doi.org/10.1016/j.physa.2010.03.020

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： http://dx.doi.org/10.1016/j.physa.2010.01.033

その他リンク： http://dx.doi.org/10.1016/j.physa.2010.01.033

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：その他   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：その他   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1016/j.biosystems.2007.12.001

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1103/PhysRevE.76.041130

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1002/hyp.6681

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1016/j.biosystems.2006.12.008

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http:dx.doi.org/10.1016/j.buildenv.2006.06.034

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1016/j.jtbi.2007.03.033

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1016/j.biosystems.2007.03.001

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1016/j.enbuild.2007.02.032

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1016/j.biosystems.2006.07.005

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：その他   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.buildenv.2004.08.010

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.enbuild.2004.02.002

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10546-005-2078-7

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.physd.2004.09.016

記述言語：英語   掲載種別：研究論文（学術雑誌）  

その他リンク： http://dx.doi.org/10.1016/j.biosystems.2007.05.002

記述言語：英語   出版者・発行元：Physical Review E  

Understanding how cooperation emerges in public goods games is crucial for addressing societal challenges. While optional participation can establish cooperation without identifying cooperators, it relies on specific assumptions - that individuals abstain and receive a non-negative payoff, or that nonparticipants cause damage to public goods - which limits our understanding of its broader role. We generalize this mechanism by considering nonparticipants' payoffs and their potential direct influence on public goods, allowing us to examine how various strategic motives for nonparticipation affect cooperation. Using replicator dynamics, we find that cooperation thrives only when nonparticipants are motivated by individualistic or prosocial values, with individualistic motivations yielding optimal cooperation. These findings are robust to mutation, which slightly enlarges the region where cooperation can be maintained through cyclic dominance among strategies. Our results suggest that while optional participation can benefit cooperation, its effectiveness is limited and highlights the limitations of bottom-up schemes in supporting public goods.

DOI： 10.1103/PhysRevE.111.024306

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PubMed

出版者・発行元：Nonlinear Dynamics  

During the COVID-19 pandemic, many countries face healthcare system collapses, then leading governments to recognize the importance of rational allocation of limited medical resources. Therefore, we construct an epidemic propagation model on a meta-population network using the microscopic Markov chain method. Unlike other works, our model accounts for nonlinear recovery rates due to healthcare system collapse and resource limitations. Combining Monte Carlo simulation, we analyze the impact of medical resources on the phase transition, steady state infected density and propagation threshold of disease spread. An interesting finding is that when medical resources are severely limited, allocating resources to smaller cities can most effectively contain the epidemic. Furthermore, it is found that introducing a healthcare system collapse mechanism results in two propagation thresholds, rendering the outbreak of epidemics to be dependent on the initial proportion of infected individuals. Finally, we validate our results on the constructed real population network.

DOI： 10.1007/s11071-024-10388-2

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記述言語：英語   出版者・発行元：Journal of the Royal Society Interface  

The positive impact of cooperative bots on cooperation within evolutionary game theory is well-documented. However, prior studies predominantly use discrete strategic frameworks with deterministic actions. This article explores continuous and mixed strategic approaches. Continuous strategies use intermediate probabilities for varying degrees of cooperation and focus on expected payoffs, while mixed strategies calculate immediate payoffs from actions taken within these probabilities. Using the prisoner's dilemma game, this study examines the effects of cooperative bots on human cooperation in both well-mixed and structured populations across these strategic approaches. Our findings reveal that cooperative bots significantly enhance cooperation in both population types under weak imitation scenarios, where players are less concerned with material gains. Conversely, under strong imitation scenarios, cooperative bots do not alter the defective equilibrium in well-mixed populations but have varied impacts in structured populations. Specifically, they disrupt cooperation under discrete and continuous strategies but facilitate it under mixed strategies. These results highlight the nuanced effects of cooperative bots within different strategic frameworks and underscore the need for careful deployment, as their effectiveness is highly sensitive to how humans update their actions and their chosen strategic approach.

DOI： 10.1098/rsif.2024.0427

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PubMed

出版者・発行元：Science China Information Sciences  

Why do humans punish free riders at their own expense? This behavior represents an evolutionary puzzle in human societies. This study explores the role of exit strategies in fostering altruistic punishment within evolutionary game theory. We extend the traditional prisoner’s dilemma model by incorporating exiters, players who opt out for a small payoff while nullifying their opponent’s payoff, and altruistic punishers who cooperate and punish non-cooperators. Our findings indicate that in well-mixed populations, exiters destabilize defection but do not promote altruistic punishment. In social networks, however, exiters enable altruistic punishment via cyclic dominance among altruistic punishers, defectors, and exiters. Notably, this cyclic dominance is sensitive to exit payoffs; adjustments can lead to cyclic dominance of non-punishing cooperators, defectors, and exiters, or to a bi-stable state between these two types of cyclic dominance. These results highlight the nuanced impact of exiters on altruistic punishment, emphasizing the need for careful incentivization of exit behavior. While exiters can support altruistic punishment in networked populations, their effectiveness is not a panacea and is highly sensitive to exit payoffs, indicating limits to the voluntary participation mechanism.

DOI： 10.1007/s11432-023-4170-3

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出版者・発行元：Alexandria Engineering Journal  

This study delves into the relationship between individual vaccination aspirations and their repercussions within the SEIRS epidemic framework, exploring effects on vaccination behavior, infection dynamics, and societal outcomes through the Vaccination Game concept. The co-evolution of epidemic dynamics and individual decision-making is examined, utilizing the social efficiency deficit (SED) to quantify a social dilemma. A novel aspiration-based model is compared with the conventional cost-based model. Higher aspiration levels correspond to increased vaccination rates, reducing overall infections. Contrary to assumptions favoring natural infection in low transmission scenarios, vaccination proves pivotal even in such contexts. Elevated transmission and immunity waning rates necessitate intensified vaccination for effective infection control, thereby reducing social dilemmas. Low vaccine efficiency coupled with high transmission rates escalates SED, but a specific vaccine efficacy threshold notably diminishes SED. Lower aspiration levels contribute to vaccine hesitancy, elevating SED, and infection rates. Surpassing an aspiration threshold redirects preferences towards vaccination, aligning with socially optimal scenarios and alleviating social dilemmas. The comparative analysis underscores the aspiration-driven approach outperforms in reducing SED, establishing its reliability in mitigating societal disease impact over the cost-based approach, but the optimal choice depends on specific epidemic conditions

DOI： 10.1016/j.aej.2024.10.087

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出版者・発行元：Applied Mathematics and Computation  

In this paper, we construct a nonlinear evolutionary game model to analyze the cooperation mechanisms of the population based on a nonlinear relationship among environment and strategies. In the model, replicator dynamics and aspiration dynamics are used to explore the evolutionary outcomes of collective decision, respectively. The results suggest that the environment tends to become progressively more affluent as the number of cooperators increases, if there is a smaller intensity of environmental destruction of defectors. Interestingly, the enriched environments may attract more defectors. Hence, the population requires a higher level of vigilance against plentiful environments in response to the emergence of defectors. As opposed to replicator dynamics, aspiration dynamics can avoid the persistent oscillatory loops due to the level of aspiration. Further, we investigate the effect of complexity between the population strategy and the environment on the evolutionary outcomes. It is found that higher level of complexity can drive the environment closer to a state of affluence, but the population's strategy structure will not be modified. These insights into the relationship between environment and strategies further our understanding of the evolutionary mechanism of population and society.

DOI： 10.1016/j.amc.2024.128990

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記述言語：英語   出版者・発行元：Proceedings of the National Academy of Sciences of the United States of America  

Stylized experiments, the public goods game and its variants thereof, have taught us the peculiar reproducible fact that humans tend to cooperate (or contribute to shared resources) more than expected from economically rational assumptions. There have been two competing explanations for this phenomenon: Either cooperating is an innate human trait (the prosocial preference hypothesis) or a transitory effect while learning the game (the confused learner hypothesis). We use large-scale experimental data in the two-player version of the public goods game—the prisoner’s dilemma—from an experimental design to distinguish between these two hypotheses. By monitoring the effects of zealots (persistently cooperating bots) and varying the participants’ awareness of them, we find a considerably more complex scenario than previously reported. People indeed have a prosocial bias, but not to the degree that they always forego taking action to increase their profit. While our findings end the simplistic theorizing of prosociality, an observed positive, cooperative response to zealots has actionable policy implications.

DOI： 10.1073/pnas.2412195121

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記述言語：英語   出版者・発行元：International Exchange and Innovation Conference on Engineering and Sciences  

With advancements in science and technology, weather is not controlled by human mechanisms and disrupts various aspects of societal life. Especially in bad weather, traffic flow dynamics are severely affected. To address this issue, we develop a modified traffic model that mitigates traffic instability by building on the conventional full velocity difference (FVD) model and incorporating factors such as pulling effect and bad weather. These properties were previously absent in the FVD model, which exhibits internal traffic noise affecting the dynamics of traffic systems. To examine our proposed model, we conduct a linear stability analysis to capture the neutral stability conditions, dividing the area into three realms: stable, unstable, and metastable. Our findings demonstrate that the new model significantly outperforms the FVD model in eliminating traffic instability, offering a robust solution to maintaining stable traffic flow considering challenging weather. PACS numbers: Theory and modeling; computer simulation, 87.15. Aa; Dynamics evolution, 87.23kg

DOI： 10.5109/7323422

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CiNii Research

記述言語：英語   出版者・発行元：International Exchange and Innovation Conference on Engineering and Sciences  

Synchronous and cooperative behaviors are widely observed in economic, social and theoretical research. However, studies that integrate these two aspects are relatively rare. This paper introduces the concepts of cost and benefit into the classical Kuramo to model, based on an ER network. By comparing the traditional random selection method with the optimal selection method, we find that the optimal selection method significantly better promotes the maintenance of cooperative and synchronized behaviors.

DOI： 10.5109/7323324

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CiNii Research

出版者・発行元：Nonlinear Dynamics  

In this study, a traffic flow model, the so-called Taillight Adapting (TA) traffic model, is developed considering the driver's activities impact following the taillight effect of the preceding vehicle, which is switched on and off based on the vehicle's accelerations and decelerations. To quantify a driver's sensitivity to the velocity gap, we introduced the concept of the new driver's sensitivity function, which has twofold formulations. The first formulation follows the HDDS model (Hossain and Tanimoto in Sci Rep 12:1–4, 2022), which presumes sensitivity depends on a headway distance. The second formulation presumes that the sensitivity depends on a velocity gap, which the taillight might inform of a preceding vehicle. We have calibrated the neutralizing proficiency of a traffic flow field for the HDDS and proposed the TA model by utilizing the linear stability theory. Finally, a series of numerical simulations of the improved TA model and conventional FVD model have been carried out to investigate how the traffic flow field for the TA model behaves differently from the conventional FVD model.

DOI： 10.1007/s11071-024-09964-3

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出版者・発行元：Chaos, Solitons and Fractals  

The evolution of cooperation in asymmetric populations has recently garnered widespread attention. In this study, we propose a new asymmetric model to explore the impact of asymmetric behavior on cooperation evolution. Our model assumes that weak players are always forced to cooperate when interacting with strong players, while strong players always receive the temptation payoff. When encountering peers from the same category, players engage in a prisoner's dilemma game, differing only in the intensity of the dilemma between population categories. Results suggest that in scenarios where traditional network reciprocity can support cooperation, asymmetric interactions between strong and weak players undermine this reciprocity and jeopardize the maintenance of cooperation. Conversely, in scenarios where traditional network reciprocity fails to support cooperation, asymmetric interactions enable strong players to leverage weak cooperative clusters to establish cooperation. However, as the prevalence of asymmetric interactions increases, it becomes detrimental to cooperation within the weak player subgroups, thus undermining overall cooperation. These findings contribute to a deeper understanding of how asymmetry impacts cooperation.

DOI： 10.1016/j.chaos.2024.115399

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記述言語：英語   出版者・発行元：Chaos  

Existing studies have revealed a paradoxical phenomenon in public goods games, wherein destructive agents, harming both cooperators and defectors, can unexpectedly bolster cooperation. Building upon this intriguing premise, our paper introduces a novel concept: constructive agents, which confer additional benefits to both cooperators and defectors. We investigate the impact of these agents on cooperation dynamics within the framework of public goods games. Employing replicator dynamics, we find that unlike destructive agents, the mere presence of constructive agents does not significantly alter the defective equilibrium. However, when the benefits from constructive agents are outweighed by the damage inflicted by destructive agents, the addition of constructive agents does not affect the ability of destructive agents to sustain cooperation. In this scenario, cooperators can be maintained through a cyclic dominance between cooperators, defectors, and destructive agents, with constructive agents adding complexity but not fundamentally changing the equilibrium. Conversely, if the benefits from constructive agents surpass the harm caused by destructive agents, the presence of constructive agents nullifies the ability of destructive agents to foster cooperation. Our results highlight the nuanced role of constructive agents in cooperation dynamics, emphasizing the necessity of carefully assessing incentive balances when encouraging cooperation.

DOI： 10.1063/5.0231158

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記述言語：英語   出版者・発行元：Physical Review E  

Destructive agents, who opt out of the game and indiscriminately harm others, paradoxically foster cooperation, representing an intriguing variant of the voluntary participation strategy. Yet, their impact on cooperation remains inadequately understood, particularly in the context of pairwise social dilemma games and in comparison to their counterparts, constructive agents, who opt out of the game but indiscriminately benefit others. Furthermore, little is known about the combined effects of both agent types on cooperation dynamics. Using replicator dynamics in infinite and well-mixed populations, we find that contrary to their role in facilitating cooperation in multiplayer games, destructive agents fail to encourage cooperation in pairwise social dilemmas. Instead, they replace defection in the prisoners' dilemma and stag-hunt games. Similarly, in the chicken game, they can destabilize or replace the mixed equilibrium of cooperation and defection, undermining cooperation in the harmony (trivial) game. Conversely, constructive agents, when their payoffs exceed their contributions to opponents, can exhibit effects similar to destructive agents. However, if their payoffs are lower, while they destabilize defection in prisoners' dilemma and stag-hunt games, they do not disrupt the cooperation equilibrium in harmony games and have a negligible impact on the coexistence of cooperation in chicken games. The combination of destructive and constructive agents does not facilitate cooperation, but instead generates complex evolutionary dynamics, including bistable, tristable, and quadstable states, with outcomes contingent on their relative payoffs and game types. These results, taken together, enhance our understanding of the impact of the voluntary participation mechanism on cooperation, contributing to a more comprehensive understanding of its influence.

DOI： 10.1103/PhysRevE.110.034307

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記述言語：英語   出版者・発行元：Infectious Disease Modelling  

In this research, we introduce a comprehensive epidemiological model that accounts for multiple strains of an infectious disease and two distinct vaccination options. Vaccination stands out as the most effective means to prevent and manage infectious diseases. However, when there are various vaccines available, each with its costs and effectiveness, the decision-making process for individuals becomes paramount. Furthermore, the factor of waning immunity following vaccination also plays a significant role in influencing these choices. To understand how individuals make decisions in the context of multiple strains and waning immunity, we employ a behavioral model, allowing an epidemiological model to be coupled with the dynamics of a decision-making process. Individuals base their choice of vaccination on factors such as the total number of infected individuals and the cost-effectiveness of the vaccine. Our findings indicate that as waning immunity increases, people tend to prioritize vaccines with higher costs and greater efficacy. Moreover, when more contagious strains are present, the equilibrium in vaccine adoption is reached more rapidly. Finally, we delve into the social dilemma inherent in our model by quantifying the social efficiency deficit (SED) under various parameter combinations.

DOI： 10.1016/j.idm.2024.03.004

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記述言語：英語   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/7236803

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CiNii Research

出版者・発行元：Physica A: Statistical Mechanics and its Applications  

A brand-new traffic model is introduced to precisely simulate the individual movement of vehicles, departing from the traditional macroscopic perspective (Eulerian scope or fluid dynamics concept) to adopt a microscopic approach (Lagrangian scope). This model is built on the first principle of Newton's kinetic equation, explicitly incorporating nonlinear relations to represent human responses to a physical stimulus (observed information), such as the velocity gap between one's own vehicle and a certain targeted one or the gap to a preceding vehicle, unlike the conventional car-following concept. The model posits that a driver's recognition occurs intermittently rather than continuously, following specific probabilistic distributions of which the formulation is physically justified. Overall, the model can be described as a spatiotemporally continuous formulation unlike cellular automaton (CA) traffic models, crucial for capturing traffic dynamics at the micro and macro levels. The model is validated using a real traffic-flow dataset from a highway, and the results of the conventional CA traffic model are compared with those of the present one” along with a note for authorial verification. Animated simulations confirm that the present model can reproduce realistic flow dynamics characterized by smoother acceleration and deceleration compared to the conventional CA traffic model. The complete simulation source code for replicating the model is made publicly available.

DOI： 10.1016/j.physa.2024.129930

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出版者・発行元：Physica A: Statistical Mechanics and its Applications  

In this study, a novel traffic model, namely the push-pull model (PPM), has been developed considering not only forward-looking effects but also how focal vehicles are influenced by their following vehicle. The developed model represents a traffic flow field whose flow is significantly different from the conventional full velocity difference model in the congestion region but is analogous to the actual traffic flow system. We focused on linear analysis, nonlinear analysis, and numerical simulation to validate our model. Linear stability analysis determines the stability condition, delineating stable and unstable regions of traffic flow. The phase diagram of stability analysis demonstrates that the PPM has a crucial positive impact on traffic flow stabilization. In the case of nonlinearity, a kink-antikink soliton solution is generated from the modified Korteweg-de Vries equation, which is derived from the push-pull effect model to interpret traffic congestion. Furthermore, to check the validity of the theoretical results of this model, a numerical simulation has been conducted, demonstrating significant suppression of traffic congestion by considering push and pull effects.

DOI： 10.1016/j.physa.2024.129816

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記述言語：英語   出版者・発行元：Scientific Reports  

In the face of infectious disease outbreaks, the collective behavior of a society can has a profound impact on the course of the epidemic. This study investigates the instantaneous social dilemma presented by individuals' attitudes toward vaccine behavior and its influence on social distancing as a critical component in disease control strategies. The research employs a multifaceted approach, combining modeling techniques and simulation to comprehensively assess the dynamics between social distancing attitudes and vaccine uptake during disease outbreaks. With respect to modeling, we introduce a new vaccination game (VG) where, unlike conventional VG models, a 2-player and 2-strategy payoff structure is aptly embedded in the individual behavior dynamics. Individuals' willingness to adhere to social distancing measures, such as mask-wearing and physical distancing, is strongly associated with their inclination to receive vaccines. The study reveals that a positive attitude towards social distancing tends to align with a higher likelihood of vaccine acceptance, ultimately contributing to more effective disease control. As the COVID-19 pandemic has demonstrated, swift and coordinated public health measures are essential to curbing the spread of infectious diseases. This study underscores the urgency of addressing the instantaneous social dilemma posed by individuals' attitudes. By understanding the intricate relationship between these factors, policymakers, and healthcare professionals can develop tailored strategies to promote both social distancing compliance and vaccine acceptance, thereby enhancing our ability to control and mitigate the impact of disease outbreaks in the future.

DOI： 10.1038/s41598-024-64143-z

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記述言語：英語   出版者・発行元：PNAS Nexus  

Addressing collective issues in social development requires a high level of social cohesion, characterized by cooperation and close social connections. However, social cohesion is challenged by selfish, greedy individuals. With the advancement of artificial intelligence (AI), the dynamics of human–machine hybrid interactions introduce new complexities in fostering social cohesion. This study explores the impact of simple bots on social cohesion from the perspective of human–machine hybrid populations within network. By investigating collective self-organizing movement during migration, results indicate that cooperative bots can promote cooperation, facilitate individual aggregation, and thereby enhance social cohesion. The random exploration movement of bots can break the frozen state of greedy population, help to separate defectors in cooperative clusters, and promote the establishment of cooperative clusters. However, the presence of defective bots can weaken social cohesion, underscoring the importance of carefully designing bot behavior. Our research reveals the potential of bots in guiding social self-organization and provides insights for enhancing social cohesion in the era of human–machine interaction within social networks.

DOI： 10.1093/pnasnexus/pgae223

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記述言語：英語   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/7183305

CiNii Research

出版者・発行元：International Journal of Modern Physics C  

This study explored whether a policy with maximum velocity limitation prior to each jam point in a traffic flow system can mitigate jam situations in a highway. To quantify this question, a new cellular automata traffic model based on the Revised S-NFS model was established. We perused two specific scenarios: a jam naturally brought by a high traffic density, and one brought by a lane-closed section placed as an explicit bottleneck. The result of multi-agent simulation (MAS) reveals that such maximum velocity limitation policy can certainly mitigate jam situations when each jam is naturally bought up not by a bottleneck, as proved by several statistics, and cannot improve the traffic flux.

DOI： 10.1142/S012918312450075X

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出版者・発行元：Neurocomputing  

Cooperation in human interactions often involves voluntary participation rather than obligatory requirements. This paper investigates the impact of voluntary exit strategies on cooperation within scale-free networks, employing spatial prisoner's dilemma games as the framework. We analyze three distinct exit strategies: leader priority exit, fringe priority exit, and random exit, across varying dilemma strengths. Our findings reveal that in scenarios of weak dilemma strength, leader priority exit significantly diminishes cooperation, particularly when only a small subset of players is granted exit rights. In contrast, under strong dilemma strength conditions, both leader priority and random exits serve to unexpectedly bolster cooperation. This enhancement is primarily facilitated by high-degree nodes opting out, thereby enabling low-degree nodes to establish stable cooperation. Furthermore, our study underscores the pivotal role of network structure. In assortative networks, random exit emerges as the most effective strategy in promoting cooperation. On the other hand, disassortative networks exhibit a substantial increase in cooperation levels when employing leader priority exit. These results highlight the intricate interplay between exit strategies, dilemma strength, and network topology, offering critical insights for promoting cooperation in varied social contexts.

DOI： 10.1016/j.neucom.2024.127566

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記述言語：英語   出版者・発行元：Chaos  

Evolutionary game theory, encompassing discrete, continuous, and mixed strategies, is pivotal for understanding cooperation dynamics. Discrete strategies involve deterministic actions with a fixed probability of one, whereas continuous strategies employ intermediate probabilities to convey the extent of cooperation and emphasize expected payoffs. Mixed strategies, though akin to continuous ones, calculate immediate payoffs based on the action chosen at a given moment within intermediate probabilities. Although previous research has highlighted the distinct impacts of these strategic approaches on fostering cooperation, the reasons behind the differing levels of cooperation among these approaches have remained somewhat unclear. This study explores how these strategic approaches influence cooperation in the context of the prisoner’s dilemma game, particularly in networked populations with varying clustering coefficients. Our research goes beyond existing studies by revealing that the differences in cooperation levels between these strategic approaches are not confined to finite populations; they also depend on the clustering coefficients of these populations. In populations with nonzero clustering coefficients, we observed varying degrees of stable cooperation for each strategic approach across multiple simulations, with mixed strategies showing the most variability, followed by continuous and discrete strategies. However, this variability in cooperation evolution decreased in populations with a clustering coefficient of zero, narrowing the differences in cooperation levels among the strategies. These findings suggest that in more realistic settings, the robustness of cooperation systems may be compromised, as the evolution of cooperation through mixed and continuous strategies introduces a degree of unpredictability.

DOI： 10.1063/5.0205330

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出版者・発行元：Applied Mathematics and Computation  

Human behaviors are strongly influenced by social norms. This work couples injunctive social norms with evolutionary games. Injunctive norms refer to behaviors which individuals should conform to and thereby entail social pressure to adhere to a particular action. Here we investigate impact of such social norms on both pairwise and multi-player games. It is shown that injunctive norms can enforce the system to either extreme, meaning that they give rise to the possibility of bi-stability (two stable equilibrium states) in evolutionary games. We derive the condition for such bi-stability in the mean-field limit. While investigating pairwise games with social norms, we observe that —besides other possibilities—Prisoner's dilemma (PD), snow-drift (SD), and Trivial (TR) games may experience the bi-stability like the stag-hunt (SH) game. Interestingly, SD game with social norms exhibits four possible asymptotic outcomes: all-cooperation (AllC), all-defection (AllD), either AllC or AllD (bi-stable), and coexistence. However, its multi-player variant does not manifest a unique coexistence equilibrium. Moreover, it demonstrates another bi-stable equilibrium, comprising either coexistence or AllC, besides other outcomes observed in the two-player case. Conversely, PD and its multi-player variant, i.e., public goods game with injunctive norms show identical evolutionary outcomes (AllD or bi-stable).

DOI： 10.1016/j.amc.2023.128463

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記述言語：英語   出版者・発行元：Journal of the Royal Society Interface  

Prosocial punishment, an important factor to stabilize cooperation in social dilemma games, often faces challenges like second-order free-riders—who cooperate but avoid punishing to save costs—and antisocial punishers, who defect and retaliate against cooperators. Addressing these challenges, our study introduces prosocial punishment bots that consistently cooperate and punish free-riders. Our findings reveal that these bots significantly promote the emergence of prosocial punishment among normal players due to their ‘sticky effect’—an unwavering commitment to cooperation and punishment that magnetically attracts their opponents to emulate this strategy. Additionally, we observe that the prevalence of prosocial punishment is greatly enhanced when normal players exhibit a tendency to follow a ‘copying the majority’ strategy, or when bots are strategically placed in high-degree nodes within scale-free networks. Conversely, bots designed for defection or antisocial punishment diminish overall cooperation levels. This stark contrast underscores the critical role of strategic bot design in enhancing cooperative behaviours in human/AI interactions. Our findings open new avenues in evolutionary game theory, demonstrating the potential of human–machine collaboration in solving the conundrum of punishment.

DOI： 10.1098/rsif.2024.0019

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記述言語：英語   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/7172183

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CiNii Research

出版者・発行元：Computational Economics  

The evolution of cooperation in social interactions remains a central topic in interdisciplinary research, often drawing debates on altruistic versus self-regarding preferences. Moving beyond these debates, this study investigates how autonomous agents (AAs) with a range of social preferences interact with human players in one-shot, anonymous prisoner’s dilemma games. We explore whether AAs, programmed with preferences that vary from self-interest to other-regarding behavior, can foster increased cooperation among humans. To do this, we have refined the traditional Bush–Mosteller reinforcement learning algorithm to integrate these diverse social preferences, thereby shaping the AAs’ strategic behavior. Our results indicate that even a minority presence of AAs, programmed with a moderate aspiration level, can significantly elevate cooperation levels among human participants in well-mixed situations. However, the structure of the population is a critical factor: we observe increased cooperation in well-mixed populations when imitation strength is weak, whereas networked populations maintain enhanced cooperation irrespective of the strength of imitation. Interestingly, the degree to which AAs promote cooperation is modulated by their social preferences. AAs with pro-social preferences, which balance their own payoffs with those of their opponents, foster the highest levels of cooperation. Conversely, AAs with either extremely altruistic or purely individualistic preferences tend to hinder cooperative dynamics. This research provides valuable insights into the potential of advanced AAs to steer social dilemmas toward more cooperative outcomes. It presents a computational perspective for exploring the complex interplay between social preferences and cooperation, potentially guiding the development of AAs to improve cooperative efforts in human societies.

DOI： 10.1007/s10614-024-10559-8

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出版者・発行元：Physical Review Research  

The critical mass effect is a prevailing topic in the study of complex systems. Recent research indicates that a committed minority of cooperators, unwavering in their beliefs and consistently maintaining cooperation, can effectively foster widespread cooperation in social dilemma games. However, achieving a critical mass of cooperation in the one-shot prisoner's dilemma requires stricter conditions. The underlying mechanism behind this effect remains unclear, particularly in the context of repeated interactions. This work aims to investigate the influence of a committed minority on cooperation in the iterated prisoner's dilemma game, a widely studied model of repeated interactions between individuals confronting a social dilemma. In contrast to previous findings, we identify tipping points for both well-mixed and structured populations. Our findings demonstrate that a committed minority of unconditional cooperators can induce full cooperation under weak imitation conditions. Conversely, a committed minority of conditional cooperators, who employ extortion strategy, can promote widespread cooperation under strong imitation conditions. These results are consistent across various network topologies and imitation rules, suggesting that critical mass effects may be a universal principle in social dilemma games. Moreover, we discovered that an excessive density of committed extortioners can hinder cooperation in structured populations. This research advances our understanding of the role of committed minorities in shaping social behavior and provides valuable insights into cooperation dynamics.

DOI： 10.1103/PhysRevResearch.6.013062

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記述言語：英語   出版者・発行元：Heliyon  

This work addressed the effect of heterogeneous vehicle sizes on traffic flow fields by introducing a movement control protocol. Considering a continuum traffic model, a new equilibrium velocity function that is dependent on traffic density was introduced to account for the effect of vehicle size. The established model showed a quantitative comparison between the Optimal Velocity and Full Velocity Difference models. A neutral stability test was carried out to evaluate the model's capability of neutralizing flow fields. The density wave behavior near a critical point was portrayed by deducing the Korteweg–de Vries–Burgers equation through a nonlinear analysis. A series of numerical simulations, the outcomes of which agreed well with the analytical results, was performed to observe the overall flow field scenario.

DOI： 10.1016/j.heliyon.2024.e23975

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出版者・発行元：Lecture Notes in Electrical Engineering  

Skin friction along with pressure and temperature is an important parameter in fluid mechanics. This study presents the results of skin-friction patterns on axisymmetric boattail surfaces by a sub-grid measurement technique. The skin-friction results indicate that detailed flow fields on the surface can be obtained when numerical parameters are selected appropriately. The effect of freestream velocity on the skin-friction streamlines and skin-friction magnitude was also discussed in detail.

DOI： 10.1007/978-981-97-3998-1_16

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出版者・発行元：Lecture Notes in Electrical Engineering  

This study focuses on the mixing layer of two free streams under incompressible conditions. The convective Mach number was changed between 0.05 to 0.3. The detached eddy simulation with turbulent model k-ε was used for the calculation. The results of numerical data were validated with experimental data with the same convective Mach number of 0.185. The results indicated that the numerical scheme provided sufficient accurate data. The averaged flow fields, turbulent kinetic energy, and unsteady behavior were analyzed and discussed insight in this study.

DOI： 10.1007/978-981-97-3998-1_117

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出版者・発行元：ICAS Proceedings  

The article constructs a convolutional neural network for predicting pressure and velocity fields around a twodimensional aircraft wing model (airfoil model). Training data is computed using the Reynolds-averaged method,then extracted, focusing on the flow around the wing. Input data includes geometric parameters, airfoil inlet velocity, and output data includes pressure field and flow velocity around the airfoil. The convolutional neural network is based on improving the U-Net network model, commonly used in medical applications. The results show that the convolutional neural network accurately predicts flow around the airfoil, with an average error below 3%. Therefore, this network can be used and further developed to predict flow around the wing. Results related to pressure distribution, velocity, and method error are presented and discussed in the study.

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出版者・発行元：ICAS Proceedings  

The utilization of longitudinal grooves has demonstrated effectiveness in reducing drag on axisymmetric boattail models. However, the intricate relationship between groove parameters and drag force defies simple physical equations, necessitating the discovery of an optimal parameter set. Conventional experimental and numerical simulation approaches prove impractical due to their resource-intensive nature. Instead, Artificial Neural Networks (ANNs) offer a promising alternative. In this study, a three-layer ANN is trained using 192 examples generated by Ansys Fluent with the Reynolds-Averaged Navier-Stokes (RANS) method and the k-ω SST model. Subsequently,48 examples are employed for network validation. Comparison between ANN-predicted values and CFDdetermined drag coefficients reveals an average difference of less than 0.76%, validating the network's reliability.The ANN successfully identifies optimal groove parameters across various boattail angles, and numericalsimulations conducted on models featuring these optimal grooves further validate the ANN's accuracy in predicting drag coefficients, with a negligible deviation of only 0.98%. Additionally, analysis of flow characteristics and aerodynamics aids in understanding factors contributing to drag reduction.

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：PLoS ONE  

The COVID-19 pandemic has remarkably heightened concerns regarding the prediction of communicable disease spread. This study introduces an innovative agent-based modeling approach. In this model, the quantification of human-to-human transmission aligns with the dynamic variations in the viral load within an individual, termed “within-host” and adheres to the susceptible–infected–recovered (SIR) process, referred to as “between-host.” Variations in the viral load over time affect the infectivity between individual agents. This model diverges from the traditional SIR model, which employs a constant transmission probability, by incorporating a dynamic, time-dependent transmission probability influenced by the viral load in a host agent. The proposed model retains the time-integrated transmission probability characteristic of the conventional SIR model. As observed in this model, the overall epidemic size remains consistent with the predictions of the standard SIR model. Nonetheless, compared to predictions based on the classical SIR process, notable differences existed in the peak number of the infected individuals and the timing of this peak. These nontrivial differences are induced by the direct correlation between the time-evolving transmission probability and the viral load within a host agent. The developed model can inform targeted intervention strategies and public health policies by providing detailed insights into disease spread dynamics, crucial for effectively managing epidemics.

DOI： 10.1371/journal.pone.0295954

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physics Open  

This study explored whether the introduction of connected automated vehicles (CAVs) into human-driven vehicles (HVs) can mitigate the social dilemma caused by defective HVs that seek to overtake other vehicles by making frequent lane changes. In this regard, a cellular automata traffic model based on the revised S–NFS model, dealing with a mixed flow field composed of CAVs and HVs with multiple lanes, was established. We perused precise game theoretical analysis on the basis of the result obtained from traffic flow analysis through multi-agent simulation (MAS). As a result, the social efficiency deficit, quantifying the extent of the social dilemma behind such a specific traffic flow system, elucidates that the introduction of CAVs does not eliminate the social dilemma caused by defective HVs unless CAVs account for the vast majority of the mixed flow.

DOI： 10.1016/j.physo.2023.100176

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記述言語：英語   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/7160863

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CiNii Research

記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos, Solitons and Fractals  

We present an evolutionary game model combining subordinate elements from several viewpoints to address whether a resource-storing mechanism promotes a society where the wealthy engage in or refrain from conflict. The model is based on the pairwise game, which incorporates the accumulation of payoffs over time and introduces the concept of participation probability based on wealthiness. Our study encompasses four distinct game classes: Prisoner's Dilemma, Trivial, Stag Hunt, and Chicken. By incorporating these diverse social dilemma structures, we strive to comprehensively understand the dynamics within different game scenarios. Additionally, we broaden the scope of our analysis by considering two network types: a regular lattice network and a Barabasi-Albert scale-free (BA-SF) graph. Through simulation results, we have discovered that the commonly held belief or human philosophical wisdom that “the wealthy do not fight” leads to the emergence of a cooperative society, depending on the intensity of the dilemma. In contrast, our findings strongly suggest that the prevailing notion of “the wealthy do fight” fosters an imbalanced exploitation-based society where defectors who exploit the poor cooperators thrive. Further analysis shows variations in beliefs and dynamics between cooperators and defectors, highlighting the emergence of social dilemmas and the impact of payoff storage. Our result reported here proves that the proposed model based on a minimal spatial game setting by 2-player & 2-strategy game just added several subordinate components can reproduce rich, complex scenarios likely observed in a real human society.

DOI： 10.1016/j.chaos.2023.114035

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Computers and Fluids  

This study compared various numerical schemes that have been reported with the assumption that artificial compressibility aids in the realization of explicit fluid dynamics simulations for a two-dimensional cavity flow. Four artificial compressible schemes, the artificial compressible method (ACM), entropically dumped ACM (EDACM), explicit method with virtual particles (EMV), were compared with a conventional incompressible scheme (simplified marker and cell, SMAC). The purpose of the comparisons is clarifying the validity of EMV in which the artificial speed of sound can be theoretically determined. In addition, the effect of the artificial speed of sound was investigated for ACM and compared with EMV. Moreover, three conditions of Reynolds numbers, Re=100, 1000, and 5000, were employed. Under steady-state conditions, the velocity and pressure distributions were found to be consistent among the EMV, ACM, EDACM, and SMAC. Further, the comparisons of the horizontal and vertical profiles indicated that these artificial compressible schemes reproduced the velocities using the incompressible scheme at three Reynolds numbers. In contrast, the temporal development of the velocity fields in the three artificial compressible schemes clearly exhibited small fluctuations in the velocity and pressure around the overall trends determined by SMAC. Further, the power spectral densities demonstrated that such fluctuations were due to compression-wave propagations with the artificial speed of sound. Although no clear differences were observed among EMV, ACM, and EDACM at these Reynolds numbers, EMV was determined to be advantageous in terms of theoretically determining the unique value of the artificial speed of sound once the lattice-grid system was fixed, whereas ACM and EDACM require sensitivity studies to select suitable values.

DOI： 10.1016/j.compfluid.2023.105985

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出版者・発行元：EPL  

Committed individuals, who feature steadfast dedication to advocating strong beliefs, values, and preferences, have garnered much attention across statistical physics, social science, and computer science. This survey delves into the profound impact of committed individuals on social dynamics that emerge from coordination games and social dilemma games. Through separate examinations of their influence on coordination, including social conventions and color coordination games, and social dilemma games, including one-shot settings, repeated settings, and vaccination games, this survey reveals the significant role committed individuals play in shaping social dynamics. Their contributions range from accelerating or overturning social conventions to addressing cooperation dilemmas and expediting solutions for color coordination and vaccination issues. Furthermore, the survey outlines three promising directions for future research: conducting human behavior experiments for empirical validation, leveraging advanced large language models as proxies for committed individuals in complex scenarios, and addressing the potential negative impacts of committed individuals.

DOI： 10.1209/0295-5075/acfb34

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Infectious Disease Modelling  

COVID-19 vaccination behavior using an SEIRM/V

DOI： 10.1016/j.idm.2023.06.001

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nonlinear Dynamics  

In this study, a new continuum traffic model is established in consideration of the diverse reactivity effect that emerges from driving attention and the vehicle's inertia. To instigate this diverse reactivity effect, two new functions are introduced, namely a driver's sensitivity function relying on the flow field's instantaneous density that follows a reverse tendency of optimal velocity function and an inertial equilibrium velocity function assuming the vehicle's inertia coefficient. Comparative analysis is performed using the proposed model and the conventional full velocity difference model. To ascertain the flow field neutralization capability of this model, a neutral stability analysis and the attendant neutral stability condition are derived. The complex behavior of the model near the critical point is investigated via nonlinear analysis, and the wavy solution of the Korteweg-de Vries-Burgers equation is obtained. To verify the analytical solution, a numerical simulation is performed, with the results demonstrating excellent agreement with the obtained theoretical results.

DOI： 10.1007/s11071-023-08734-x

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記述言語：英語   出版者・発行元：Vaccines  

Infectious diseases pose significant public health risks, necessitating effective control strategies. One such strategy is implementing a voluntary vaccination policy, which grants individuals the autonomy to make their own decisions regarding vaccination. However, exploring different approaches to optimize disease control outcomes is imperative, and involves assessing their associated costs and benefits. This study analyzes the advantages and disadvantages of employing a mixed-strategy approach under a voluntary vaccination policy in infectious disease control. We examine the potential benefits of such an approach by utilizing a vaccination game model that incorporates cost and benefit factors, where lower costs and higher benefits lead to reduced infection rates. Here, we introduce a mixed-strategy framework that combines individual-based risk assessment (IB-RA) and society-based risk assessment (SB-RA) strategies. A novel dynamical equation is proposed that captures the decision-making process of individuals as they choose their strategy based on personal or communal considerations. In addition, we explore the implications of the mixed-strategy approach within the context of social dilemmas. We examine deviations from expected behavior and the concept of social efficiency deficit (SED) by allowing for the evolution of vaccine strategy preferences alongside risk perception. By comprehensively evaluating the financial implications and societal advantages associated with the mixed-strategy approach, decision-makers can allocate resources and implement measures to combat infectious diseases within the framework of a voluntary vaccination policy.

DOI： 10.3390/vaccines11091476

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記述言語：英語   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/7148431

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出版者・発行元：Alexandria Engineering Journal  

In this study, an epidemiological model with the provaccination and antivaccination susceptible groups is proposed, and the social dilemma of the model is analyzed. During a pandemic, such as the current COVID-19, many individuals get confused to choose the option of adopting a provaccination or antivaccination strategy based on the number of infected people and the payoff of being infected. In the proposed model, people can obtain immunity either through vaccination or by getting infected with the disease which is known as natural immunity. In addition, increasing the waning immunity influences the choice of adopting the provaccination or antivaccination strategy. We used the behavior model to analyze the choice of the two strategies, where any individual can choose a strategy based on the number of infected individuals from each group. Moreover, individuals who are already infected can choose their strategy based on the payoff of their disease cost or vaccination cost. Our results show that, at Nash equilibrium, individuals in both groups behave the same. Further, from our numerical results, increasing the number of vaccinations can reduce the social dilemma whereas an increase in the waning immunity rate increases the social dilemma.

DOI： 10.1016/j.aej.2023.05.091

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Royal Society Interface  

Cooperation plays a crucial role in both nature and human society, and the conundrum of cooperation attracts the attention from interdisciplinary research. In this study, we investigated the evolution of cooperation in optional Prisoner's Dilemma games by introducing simple bots. We focused on one-shot and anonymous games, where the bots could be programmed to always cooperate, always defect, never participate or choose each action with equal probability. Our results show that cooperative bots facilitate the emergence of cooperation among ordinary players in both well-mixed populations and a regular lattice under weak imitation scenarios. Introducing loner bots has no impact on the emergence of cooperation in well-mixed populations, but it facilitates the dominance of cooperation in regular lattices under strong imitation scenarios. However, too many loner bots on a regular lattice inhibit the spread of cooperation and can eventually result in a breakdown of cooperation. Our findings emphasize the significance of bot design in promoting cooperation and offer useful insights for encouraging cooperation in real-world scenarios.

DOI： 10.1098/rsif.2023.0301

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER  

In this study, an epidemiological model with the provaccination and antivaccination sus-ceptible groups is proposed, and the social dilemma of the model is analyzed. During a pandemic, such as the current COVID-19, many individuals get confused to choose the option of adopting a provaccination or antivaccination strategy based on the number of infected people and the payoff of being infected. In the proposed model, people can obtain immunity either through vaccination or by getting infected with the disease which is known as natural immunity. In addition, increasing the waning immunity influences the choice of adopting the provaccination or antivaccination strategy. We used the behavior model to analyze the choice of the two strategies, where any individual can choose a strategy based on the number of infected individuals from each group. Moreover, individ-uals who are already infected can choose their strategy based on the payoff of their disease cost or vaccination cost. Our results show that, at Nash equilibrium, individuals in both groups behave the same. Further, from our numerical results, increasing the number of vaccinations can reduce the social dilemma whereas an increase in the waning immunity rate increases the social dilemma. & COPY; 2023 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

DOI： 10.1016/j.aej.2023.05.0911110-0168

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos, Solitons and Fractals  

A new SEIRS-based ODE (Ordinary Differential Equation) model is built, where asymptomatic and symptomatic infectious compartments, hospitalized state and immune state are additionally introduced, which is dovetailed with a behavior model that defines the vaccination rate as time-variable. We also apply Social Efficiency Deficit; SED, to quantitatively identify whether or not social dilemma taking place behind the model dynamics. Numerical results prove that, depending on the fraction of asymptomatic infected individuals and the discount ratio of infected force for asymptomatic state compared with that for symptomatic one, whether or not social dilemma appearing is different, which is also substantially affected by the vaccination cost and the immunity waning rate. The behavior model tends to incur a slight social dilemma brought by wasting vaccination even in the region of disease free, identified by R0 < 1. Meanwhile, a relatively strong social dilemma is indicated in the parameter region where the behavior model shows less amount of vaccinated population while the social optimal state needs much more vaccinated for complete remission of disease.

DOI： 10.1016/j.chaos.2023.113426

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

Building on safety and broad acceptance of healthcare policy, we agree that human behavior is substantial because its success depends on an individual's contribution, ethnic, economic, and social status. We present three surveys testing this account for imminent hypothetical COVID-19 vaccines in Bangladesh, Indonesia, and Malaysia to study to find the acceptance and willingness-to-pay (WTP) for a vaccine in a social context. We used the contingent valuation (CV) method to estimate WTP in Bangladesh, Malaysia, and Indonesia. The statistical ANOVA estimation mode was supposed to measure the critical factors of vaccine acceptance and WTP for three vaccines and compare the associated characteristics with conventional epidemic vaccination models. The studies investigated how an individual's vaccination behavior depends on disease severity, geographical proximity, and socioeconomic similarity. Our results demonstrate that increasing vaccine uptake has a significant impact on vaccine efficacy and disease severity, while self-reported vaccine preferences were associated with factors such as lack of education and economic conditions.

DOI： 10.5109/6792807

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Heliyon  

This study aims to develop a traffic model for heterogeneous vehicle movement, which introduces the vehicle's heterogeneity by considering the internal mass effect. We explore the behavioral characteristics of the flow field generated by the proposed model and provide a comparative analysis of the conventional model. A linear stability condition is deduced to showcase the model's capacity to neutralize flow. Nonlinear analysis is employed to derive the modified Korteweg-de Vries (mKdV) equation and its corresponding analytical solution, enabling the observation of traffic flow behavior in proximity to the neutral stability condition. A numerical simulation is then conducted, considering cyclic boundary conditions. The results indicate that the mass effect tends to absorb traffic jams provided no time delay is imposed.

DOI： 10.1016/j.heliyon.2023.e16731

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos  

Over the past decade, the coupled spread of information and epidemic on multiplex networks has become an active and interesting topic. Recently, it has been shown that stationary and pairwise interactions have limitations in describing inter-individual interactions , and thus, the introduction of higher-order representation is significant. To this end, we present a new two-layer activity-driven network epidemic model, which considers the partial mapping relationship among nodes across two layers and simultaneously introduces simplicial complexes into one layer, to investigate the effect of 2-simplex and inter-layer mapping rate on epidemic transmission. In this model, the top network, called the virtual information layer, characterizes information dissemination in online social networks, where information can be diffused through simplicial complexes and/or pairwise interactions. The bottom network, named as the physical contact layer, denotes the spread of infectious diseases in real-world social networks. It is noteworthy that the correspondence among nodes between two networks is not one-to-one but partial mapping. Then, a theoretical analysis using the microscopic Markov chain (MMC) method is performed to obtain the outbreak threshold of epidemics, and extensive Monte Carlo (MC) simulations are also carried out to validate the theoretical predictions. It is obviously shown that MMC method can be used to estimate the epidemic threshold; meanwhile, the inclusion of simplicial complexes in the virtual layer or introductory partial mapping relationship between layers can inhibit the spread of epidemics. Current results are conducive to understanding the coupling behaviors between epidemics and disease-related information.

DOI： 10.1063/5.0151881

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記述言語：英語   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/6792805

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos, Solitons and Fractals  

In this work, we extend the spatial prisoner's dilemma game by introducing three competing strategies: unconditional cooperators (C); super cooperators (SC); and speculative defectors (SD). Unconditional cooperators cooperate with their opponent no matter what the opponent does. In contrast, SC first cooperate with their opponent, then reward or punish them based on whether the opponent cooperated or defected. SD cooperate with SC based on certain prior information level, but otherwise defect as default. We investigated the evolutionary dynamics of the extended prisoner's dilemma game in structured populations. Through extensive Monte Carlo simulations, we showed that increasing the information level q generally facilitates the evolution of SC, but destroys them if the cost of SC is high. Counterintuitively, SD who cooperate with SC can form an active layer around them, which eliminates the free riding chance on SC for unconditional cooperators. Our results indicate that SD may not always impede cooperators.

DOI： 10.1016/j.chaos.2023.113391

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nonlinearity  

Imitation and aspiration learning rules are frequently observed in humans and animals. The former is an act of copying other's action, whereas the latter is characterized by the self-evaluation. Here we study the coexistence of these learning mechanisms in structured populations. Both rules have been combined focusing on two different scenarios: (I) adoption of either update rule with a certain probability, and (II) grouping the entire population according to the update rules. We present two pair approximation models, illustrating both scenarios, which yield a nice agreement-under weak selection-with that of agent-based simulations. For weak selection and large population size, we find that the condition for cooperation to dominate defection is similar in both heterogeneous and homogeneous update rules. We examine several variants of the mixed model such as time-evolving aspirations alongside strategies and the coevolution of strategies and update rules. In the former case, our simulation reveals that Prisoner's dilemma and, in some cases, Stag-hunt experience overall less aspiration levels compared to other games such as Chicken or Trivial. The coevolution of strategies and update rules demonstrates a better cooperation, in contrast to the fixed update rule case, exhibiting the possibility of asymptotic coexistence of both learning mechanisms.

DOI： 10.1088/1361-6544/acc500

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記述言語：日本語   出版者・発行元：日本地図学会  

<p>In following to our previous study that was inspired by the fine historical text; “<i>Diary of Masakiyo Mishima, Shogun’s Vassal</i>”, one certain particular urban block area, where Mishima main manor used to locate in Ishihara district, Honjo, Tokyo (Edo), is carefully explored so as to draw a historical perspective of how urban block alteration has taken place for hundreds years from Edo-Era up to now, Reiwa-era.</p><p>One interesting finding is that, at the moment of Meiji Revolution, which demolished Tokugawa-House; Shogun’s Government and newly established the modern government of Imperial Japan, although Mishima Family lost the ownership of the main manor, another high-class vassal sharing the same district, more precisely; one of the neighbors of Mishima, Negoro Family was able to keep the ownership of their main manor that was much larger than that of Mishima.</p><p>In terms of statistical values; average site area and its standard deviation, the focal district did not significantly change until the early time of 20th century even after Meiji Revolution. Yet, Great Kanto earthquake of 1923 impacted the district to alter very much. It is because the land relocation project (LRP) after the earthquake was introduced by the central government as well as the Tokyo Metropolitan government, which put wider block roads (which was requisite form the urban planning viewpoint) and consequently divided the focal block into many smaller sites. Approximately speaking before the LRP, such average site area over the focal district was around 1000 m², whereas after the LRP it declined down to around 100 m². Therefore, we would guess that the quality, as a residential area, of the focal district was kept at a higher level until that time, since the district was originated from the residential district of Shogun’s vassals; upper class people (upper class Samurai) at the time. However, impacted by a great fire brought by the earthquake, triggered by the LRP, the focal district was thoroughly segmentalized.</p><p>The focal district unfortunately encountered another great fire, which was brought by Great Tokyo Air Raid, took place on March 10th, 1945, which did completely burn-out most of residential buildings in Honjo Ward, mainly wooden construction, and killed more than 100,000 citizens that was almost equivalent to the death toll of Great Kanto earthquake of 1923. But, the fundamental configuration of the focal district did not change before and after WW2. In fact, the average site area over the focal district has been keeping around 100 m² from the time right after WW2 until now.</p><p>To the end of such historical discussion, we successfully drew one impressive visual figure suggesting the average area of a single-site in the focal urban block as well as the standard deviation, abovementioned, for last hundreds years. Interestingly, in the two periods before and after the LRP after Great Kanto earthquake of 1923, respective average areas of a single-site do not change significantly. It might be quite unexpected when we observed the current situation of the focal district, which is featured with a quite high density of buildings, although we know our study’s limitation; that is just based on one certain focal urban district suggesting one single example story.</p>

DOI： 10.11212/jjca.61.1_39

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos, Solitons and Fractals  

This study investigates a standard vaccination game presuming the repeated-season framework, in which we mutually merge the dynamics of disease spread, which obeys the SIR process, and human decision-making as regards whether or not to get vaccinated at the beginning of each season with reference to the evolutionary game theory. We herein presume the Barab ' asi-Albert scale-free (BA-SF) graph as an underlying network. Accordingly, we explore whether or not an additive noise to the transmission rate brings an advantageous stochastic resonance effect for confining a disease's spread. The results show that with a higher vaccination cost and/or a lower vaccine efficacy, the stochastic noise has no gap in vaccination coverage (VC) with the default without noise case, but brings a smaller final epidemic size (FES). In contrast, at a lower vaccination cost and a higher vaccine efficacy, the additive stochastic noise brings a smaller VC that consequently results in a larger FES than the default without noise case. This phenomenon is completely different from our previously reported bolstered enhancement effect of network reciprocity, in which each element of a payoff matrix is exposed to stochastic noise.

DOI： 10.1016/j.chaos.2022.113029

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掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：2023 IEEE PES Innovative Smart Grid Technologies - Asia, ISGT Asia 2023  

With the rapid spread of renewable energy, the utilizing residential air conditioners (AC) for demand response (DR) is gaining importance. As resource aggregators seek to manage the flexibility offered by a large number of AC units, accurately estimating the DR potential of ACs is essential for successful bidding in the balancing market. This study introduced a data-driven method that leverages measured electricity data from residential ACs to evaluate the DR potential and estimate the room temperature without the complex model of thermal conduction. The proposed method comprises three components: estimating the AC turn-on/off states, calculating time-dependent parameters for room temperature estimation, and determining the room temperature and AC electricity consumption after DR implementation. A case study was conducted using data from 479 dwellings in Osaka, Japan, to assess the downward DR potential during the cooling season. Results indicate a median DR potential ranging from 9.2% to 18.7% of total AC electricity consumption. This study provides valuable insights into leveraging residential ACs as flexible resources for demand response, empowering resource aggregators to make informed decisions in a balanced market.

DOI： 10.1109/ISGTAsia54891.2023.10372682

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

The emergence of antimicrobial resistance (AMR) caused by the excess use of antimicrobials has come to be recognized as a global threat to public health. There is a 'tragedy of the commons' type social dilemma behind this excess use of antimicrobials, which should be recognized by all stakeholders. To address this global threat, we thus surveyed eight countries/areas to determine whether people recognize this dilemma and showed that although more than half of the population pays little, if any, attention to it, almost 20&#37; recognize this social dilemma, and 15-30&#37; of those have a positive attitude toward solving that dilemma. We suspect that increasing individual awareness of this social dilemma contributes to decreasing the frequency of AMR emergencies.

DOI： 10.1038/s41598-022-25632-1

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Electronics and Communications in Japan  

Residential appliances remotely controlled by IoT for demand response has attracted much attention for effective peak demand reduction of the uncertainty of consumers’ behaviors. To promote the technology development of such appliances, estimation of the potential for peak demand reduction according to the type of appliances is strongly needed. With this background, the authors conducted a data analysis of demand curves of not only the entire household but also the branches acquired at 496 dwellings in Osaka. Based on this analysis, the potential of peak reduction of aggregated demand of various groups with different dwelling size were quantified for major five appliances, namely air conditioners, microwave ovens, refrigerators, washing machines, and dish washers.

DOI： 10.1002/ecj.12379

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Mathematics and Computation  

During a pandemic event like the present COVID-19, self-quarantine, mask-wearing, hy-giene maintenance, isolation, forced quarantine, and social distancing are the most effec-tive nonpharmaceutical measures to control the epidemic when the vaccination and proper treatments are absent. In this study, we proposed an epidemiological model based on the SEIR dynamics along with the two interventions defined as self-quarantine and forced quarantine by human behavior dynamics. We consider a disease spreading through a pop-ulation where some people can choose the self-quarantine option of paying some costs and be safer than the remaining ones. The remaining ones act normally and send to forced quarantine by the government if they get infected and symptomatic. The government pays the forced quarantine costs for individuals, and the government has a budget limit to treat the infected ones. Each intervention derived from the so-called behavior model has a dy-namical equation that accounts for a proper balance between the costs for each case, the total budget, and the risk of infection. We show that the infection peak cannot be reduced if the authority does not enforce a proactive (quantified by a higher sensitivity parameter) intervention. While comparing the impact of both self-and forced quarantine provisions, our results demonstrate that the latter is more influential to reduce the disease prevalence and the social efficiency deficit (a gap between social optimum payoff and equilibrium payoff).(c) 2022 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.amc.2022.127365

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Architectural Review  

In this study, the velocity field in a naturally ventilated building within an urban-like array was explored using large-eddy simulations. Reduced-scale building models were used to examine the impacts of the geometric conditions in the surrounding buildings and cross-ventilating windows on the flow statistics and instantaneous velocity fields in the sheltered building. The instantaneous velocity components averaged in the opening area were calculated for each condition of the building arrays and openings. The results indicate that the surrounding urban geometry significantly affects the turbulent opening velocities. Additionally, the three-dimensional instantaneous velocity distributions within the target building clearly demonstrate considerable differences under the different building and opening conditions. Such differences also affect the mean, maximum, and minimum wind speeds within the indoor regions. Moreover, the distributions of the two-point correlation coefficient (defined by the velocities normal to the windows at the center of the windward opening and inside the building) were compared for each condition. The strong correlations near the two openings indicate that the instantaneous velocity generated by the surrounding buildings is an important factor in determining the statistical and instantaneous features of indoor ventilating airflows.

DOI： 10.1002/2475-8876.12312

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos  

The way of information diffusion among individuals can be quite complicated, and it is not only limited to one type of communication, but also impacted by multiple channels. Meanwhile, it is easier for an agent to accept an idea once the proportion of their friends who take it goes beyond a specific threshold. Furthermore, in social networks, some higher-order structures, such as simplicial complexes and hypergraph, can describe more abundant and realistic phenomena. Therefore, based on the classical multiplex network model coupling the infectious disease with its relevant information, we propose a novel epidemic model, in which the lower layer represents the physical contact network depicting the epidemic dissemination, while the upper layer stands for the online social network picturing the diffusion of information. In particular, the upper layer is generated by random simplicial complexes, among which the herd-like threshold model is adopted to characterize the information diffusion, and the unaware-aware-unaware model is also considered simultaneously. Using the microscopic Markov chain approach, we analyze the epidemic threshold of the proposed epidemic model and further check the results with numerous Monte Carlo simulations. It is discovered that the threshold model based on the random simplicial complexes network may still cause abrupt transitions on the epidemic threshold. It is also found that simplicial complexes may greatly influence the epidemic size at a steady state. Published under an exclusive license by AIP Publishing.

DOI： 10.1063/5.0125873

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Sustainability (Switzerland)  

Understanding occupants’ behaviours (OBs) of heating and cooling use in dwellings is essential for effectively promoting occupants’ behavioural change for energy saving and achieving efficient demand response operation. Thus, intensive research has been conducted on data collection, statistical analysis, and modelling of OBs. However, the majority of smart metres currently deployed worldwide monitor only the total household consumption rather than appliance-level load. Therefore, estimating the turn-on/off state of specific home appliances from the measured household total electricity referred to as non-intrusive load monitoring (NILM), has gained research attention. However, the current NILM methods overlook the specific features of inverter-controlled heat pumps (IHPs) used for space heating/cooling; thus, they are unsuitable for detecting OBs. This study presents a rule-based method for identifying the occupants’ intended operation states of IHPs based on a statistical analysis of load data monitored at 423 dwellings. This method detects the state of IHPs by subtracting the power of sequential-operation appliances other than IHPs from the total household power. Three time-series characteristics, including the durations of power-on/off states and power differences between power-off/on states, were used for this purpose. The performance of the proposed method was validated, indicating an F-score of 0.834.

DOI： 10.3390/su142214863

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記述言語：英語   出版者・発行元：九州大学大学院総合理工学府  

The emergence of a new strain during a pandemic, like the present COVID-19, is a serious concern to the healthcare system. The most effective strategy to control this pandemic is vaccination. Many studies suggest that vaccine efficacy against the new strain may reduce. Additionally, the new strain’s late arrival has a significant impact on the disease dynamics and vaccine coverage. Focusing on these issues, this study presents a two-strain epidemic model along with two vaccination provisions based on human behavior dynamics, in which the new strain appears with a time delay. Individuals can commit vaccination before and after being infected with strain 1 and both vaccinated and non-vaccinated individuals can be infected with strain 2. Our findings suggested that delaying the second strain increases the overall vaccination coverage and reduces the peak size of the infected individuals.

DOI： 10.5109/5909084

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記述言語：英語   出版者・発行元：九州大学大学院総合理工学府  

Car-following model and its variants are proposed to reproduce real traffic flow phenomena, but they ignore that different vehicles have different inertiasm, which is out of touch with reality. In this paper, a heterogeneous vehicular inertia (HVI) model is proposed by considering the vehicle's inertia effect based on the full velocity difference (FVD) model on a single-lane road. The linear stability theory is used to determine the stability condition for this model with time delay. The results demonstrate that the higher inertia effect and lower time delay effect would strengthen the stability of the proposed model.

DOI： 10.5109/5909091

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Mathematics and Computation  

COVID-19 has emphasized that a precise prediction of a disease spreading is one of the most pressing and crucial issues from a social standpoint. Although an ordinary differential equation (ODE) approach has been well established, stochastic spreading features might be hard to capture accurately. Perhaps, the most important factors adding such stochasticity are the effect of the underlying networks indicating physical contacts among individuals. The multi-agent simulation (MAS) approach works effectively to quantify the stochasticity. We systematically investigate the stochastic features of epidemic spreading on homogeneous and heterogeneous networks. The study quantitatively elucidates that a strong microscopic locality observed in one- and two-dimensional regular graphs, such as ring and lattice, leads to wide stochastic deviations in the final epidemic size (FES). The ensemble average of FES observed in this case shows substantial discrepancies with the results of ODE based mean-field approach. Unlike the regular graphs, results on heterogeneous networks, such as Erdos-Renyi random or scale-free, show less stochastic variations in FES. Also, the ensemble average of FES in heterogeneous networks seems closer to that of the mean-field result. Although the use of spatial structure is common in epidemic modeling, such fundamental results have not been well-recognized in literature. The stochastic outcomes brought by our MAS approach may lead to some implications when the authority designs social provisions to mitigate a pandemic of un-experienced infectious disease like COVID-19. (C) 2022 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.amc.2022.127328

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

A new microscopic traffic flow model is established based on heterogeneous driver's sensitivity; in this new model, the driver's sensitivity is defined as being dependent on the headway distances to the preceding vehicle, similar to Bando's optimal velocity function. We introduce the formulation of this cognitive driver's sensitivity utilizing a modified form of Bando's optimal velocity function. A simple methodology, which is used for improving Bando's optimal velocity function, has been implemented for developing the cognitive driver's sensitivity function, which establishes a correlation between the flow field's density and human drivers' responses. The model is highly advanced for introducing a human-driven traffic flow field considering the driver's mental behavioral activity. Using the linear stability condition, we elucidate a neutral stability condition. A series of numerical simulations indicates how the present model describes dynamics that differ from the conventional model, which assumes a constant driver's sensitivity.

DOI： 10.1038/s41598-022-22412-9

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Architectural Review  

Occupants' behaviors (OBs) toward air conditioning (AC) usage in residential buildings have a strong influence on diverse time patterns of load profiles; thus, various stochastic OB modeling has been proposed. However, the validity of such models has not been fully assessed with metered data, particularly for modeling AC switching-off actions. In this study, the AC operation behavior of 20 dwellings in Japan was observed during the summer. The occurrence of AC-use events identified from the measured data was analyzed in relation to the time slot of an event, thermal conditions, and frequency of AC usage in each dwelling. The results exhibited a difference between switch-on and switch-off actions; the former is primarily dominated by indoor temperature because of thermal adaptation behavior, while the latter is more habitual. Based on this analysis, this study proposed a revised algorithm to synthesize AC operation schedules, which expresses the switch-off action as the probability of the duration of an AC-use event rather than a state transition probability function. The proposed algorithm can be incorporated into dynamic building energy simulations. The validity of the revised algorithm was also demonstrated through comparison with the measured data.

DOI： 10.1002/2475-8876.12293

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人 電気学会  

Residential appliances remotely controlled by IoT for demand response has attracted much attention for effective peak demand reduction of the uncertainty of consumers' behaviors. To promote the technology development of such appliances, estimation of the potential for peak demand reduction according to the type of appliances is strongly needed. With this background the authors conducted a data analysis of demand curves of not only entire household but also branches acquired at 496 dwellings in Osaka. Based on this analysis, the potential of peak reduction of aggregated demand of various groups with different dwelling size were quantified for major 5 appliances, namely air conditioners, microwave ovens, refrigerators, washing machines and dish washers.

DOI： 10.1541/ieejeiss.142.909

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos, Solitons and Fractals  

Motivated by an interdisciplinary question of whether a resource-storing mechanism favors "the wealthy do fight" or "the wealthy do not fight," we establish a new model based on spatial prisoner's dilemma (SPD) game where a time-accumulating payoff is allowed, and the probability of game participation depending on wealthiness is introduced. Although the model is based on a universal framework, presuming SPDs as a template, the conclusion drawn from the model is interdisciplinary rich. Our simulation results reveal that the common sense (or say, human's philosophical wisdom) of "the wealthy do not fight" helps to emerge a fairly cooperative society depending on the dilemma strength. By contrast, remarkably, it suggests that the common sense of "the wealthy do fight" begets a skewed exploitation society where defectors who exploit poor cooperators prosper.PACS numbers Theory and modeling; computer simulation, 87.15.Aa; Dynamics of evolution, 87.23.Kg.(c) 2022 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2022.112207

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos, Solitons and Fractals  

COVID-19 has shown that quarantine (or self-isolation) may be the only available tool against an unknown infectious disease if neither an effective vaccine nor anti-viral medication is available. Motivated by the fact that a considerable number of people were not compliant with the request for self-quarantine made by public authorities, this study used a multi-agent simulation model, whose results were validated by theory work, which highlights how and to what extent such an anti-social behavior hampers the confinement of a disease. Our framework quantifies two important scenarios: in one scenario a certain number of individuals totally ignore quarantine, whereas in the second scenario a larger number of individuals partially ignore the imposed policy. Our results reveal that the latter scenario can be more hazardous even if the total amount of social deficit of activity-measured by the total number of severed links in a physical network-would be same as the former scenario has, of which quantitative extent is dependent on the fraction of asymptomatic infected cases and the level of quarantine intensity the government imposing. Our findings have significance not only to epidemiology but also to research in the broader field of network science. PACS numbers: Theory and modeling; computer simulation, 87.15.Aa; Dynamics of evolution, 87.23.Kg. (c) 2022 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2022.112178

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

With the rapid prosperity of the global economy and industry, as the energy demand, many factors influence power-producing sectors, including government incentives, customer demand, production cost, eco-friendly, and investors investment. To analyze the cost-benefit-subsidy in power generator system under the evolutionary game setting, we considered two asymmetric game structures by coupling the photovoltaic (PV) power system and coal-fired (CF) power system. To model the asymmetric games for PV and CF, Game-1 considers respective cost and benefit, whereas, Game-2 deliberates cost, benefit, and government subsidy. We present both analytical and numerical approaches within this framework.

DOI： 10.5109/4793672

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

Vaccination, if available, is the best preventive measure against infectious diseases. It is, however, needed to prudently design vaccination strategies to successfully mitigate the disease spreading, especially in a time when vaccine scarcity is inevitable. Here we investigate a vaccination strategy on a scale-free network where susceptible individuals, who have social connections with infected people, are being detected and given vaccination before having any physical contact with the infected one. Nevertheless, detecting susceptible (also infected ones) may not be perfect due to the lack of information. Also, vaccines do not confer perfect immunity in reality. We incorporate these pragmatic hindrances in our analysis. We find that if vaccines are highly efficacious, and the detecting error is low, then it is possible to confine the disease spreading-by administering a less amount of vaccination-within a short period. In a situation where tracing susceptible seems difficult, then expanding the range for vaccination targets can be socially advantageous only if vaccines are effective enough. Our analysis further reveals that a more frequent screening for vaccination can reduce the effect of detecting errors. In the end, we present a link percolation-based analytic method to approximate the results of our simulation.

DOI： 10.1038/s41598-022-12039-1

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos, Solitons and Fractals  

In the wake of COVID-19, mask-wearing practice and self-quarantine is thought to be the most effective means of controlling disease spread. The current study develops an epidemiological model based on the SEIR process that takes into account dynamic human behavior toward those two preventive measures. In terms of quantifying the effect of wearing a mask, our model distinguishes itself by accounting for the effect of self-protection as well as the effect of reducing a potential risk to other individuals in different formulations. Each of the two measures de-rived from the so-called behavior model has a dynamical equation that takes into account the delicate balance between the cost of wearing a mask/self-quarantine and the risk of infection. The dynamical system as a whole contains a social dilemma structure because of whether to commit to preventing measures or seek the possibility of infection-free without paying anything. The numerical result was delivered along the social efficiency deficit, quantifying the extent to which Nash equilibrium has been improved to a social optimal state. PACS numbers Theory and modeling; computer simulation, 87.15.Aa; Dynamics of evolution, 87.23.Kg (c) 2022 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2022.112030

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Building Engineering  

In recent years, a bottom-up approach based on building-energy simulations coupled with stochastic modelling of occupant behaviours has been intensively developed to properly estimate the effect of diverse and stochastic occupant behaviours on energy loads, mainly for developing smart building-energy-management systems and the promotion of renewable energy sources. Considering this background, the objective of this study is to elucidate the modelling of the state transitional probability of occupants’ heat pump (HP) use embedded in most bottom-up approaches based on statistical analysis of the 2-year electricity data of 586 dwellings. The analysis results clearly suggested that the relationship between daily hours of HP use and the daily mean outdoor air temperature has seasonal differences, in which frequency of HP use in early summer and early winter is lower than that in late summer and late winter under the same daily mean outdoor air temperature conditions. In addition, the authors presented statistical models of daily HP use hours with an explanatory variable of outdoor temperature for a lapse of 10 days to model the seasonal influence, and showed better performance compared to the model expressed by daily mean outdoor temperature. Furthermore, the authors revealed that such a seasonal change in behaviour is attributed to the state transitional probability of cooling use as a function of indoor thermal conditions based on a numerical simulation of the bottom-up approach. Finally, the authors proposed a revised model with the state transitional probability considering seasonal behaviour change, and the estimation results of household cooling use are consistent with the measured data.

DOI： 10.1016/j.jobe.2022.104067

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

<title>Abstract</title>We present the pair approximation models for susceptible–infected–recovered (SIR) epidemic dynamics in a sparse network based on a regular network. Two processes are considered, namely, a Markovian process with a constant recovery rate and a non-Markovian process with a fixed recovery time. We derive the implicit analytical expression for the final epidemic size and explicitly show the epidemic threshold in both Markovian and non-Markovian processes. As the connection rate decreases from the original network connection, the epidemic threshold in which epidemic phase transits from disease-free to endemic increases, and the final epidemic size decreases. Additionally, for comparison with sparse and heterogeneous networks, the pair approximation models were applied to a heterogeneous network with a degree distribution. The obtained phase diagram reveals that, upon increasing the degree of the original random regular networks and decreasing the effective connections by introducing void nodes accordingly, the final epidemic size of the sparse network is close to that of the random network with average degree of 4. Thus, introducing the void nodes in the network leads to more heterogeneous network and reduces the final epidemic size.

DOI： 10.1038/s41598-022-07985-9

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その他リンク： https://www.nature.com/articles/s41598-022-07985-9

記述言語：英語   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/4774209

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本建築学会  

To reproduce homogeneous flow fields above urban-like turbulent boundary layers in computational fluid dynamics (CFD), numerous CFDs with a limited numerical domain employ periodic boundary conditions in both lateral directions with artificial momentum provision to maintain airflows. Although such artificial momentum sources are clearly different from the momentum provision in windtunnel experiments, the effects of these numerical conditions on the airflow in the boundary layer are not well studied. In this paper, therefore, we investigate how the momentum provision differentiates the vertical Reynolds stress and turbulent kinetic energy profiles using large-eddy simulations of airflows over cubical block arrays.

DOI： 10.3130/aije.87.145

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chaos, Solitons and Fractals  

A new cellular automata traffic model based on Revised S-NFS model is established to consider a mixed flow system in which the maximal velocity of the agents is distributed, as is the case in a real traf-fic flow fields composed of compact vehicles, trucks, and buses. These vehicles are assigned on of two different strategies: cooperator (C), who remains in his original lane, and defector (D), who undertakes lane-changing to maximize his own payoff, i.e., average velocity. In a systematic series of multi-agent simulations, we quantitatively compare flow characteristics in the default system (where maximal ve -locity is constant across all agents), mixed traffic flow systems (which permit a distribution of maximal velocities), and correlated-mixed traffic flows, in which an agent with a higher maximal velocity tends to have a D strategy whereas one with a lower maximal velocity tends to have a C strategy. We discuss what kind of game class is underlying in each traffic flow system. Furthermore, we quantitatively study the social efficiency deficit, an index of dilemma extent, for each of the flow systems. (c) 2022 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2022.111790

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本建築学会  

COMPUTATIONAL FLUID DYNAMICS for CROSS-VENTILATED AIRFLOW in AN URBAN BUILDING
The velocity field in a naturally ventilated building within urban-like arrays was explored by means of large-eddy simulations. The reduced-scale building models were utilized to examine the impact of the geometric conditions in surrounding buildings and cross-ventilating windows on flow statistics as well as instantaneous velocity fields in a sheltered building. The obtained results indicated how the incoming flow was propagated in the target building. Although simplified conditions were employed, the present findings of the features of cross-ventilation are valuable to consider the effect of outdoor turbulent flow to indoor wind environment.

DOI： 10.3130/aije.87.19

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CiNii Research

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physica A: Statistical Mechanics and its Applications  

In this study, we propose an information-sharing traffic flow model by considering multiple preceding cars and system time delay effect to reproduce a more likely flow field given the dissemination of intelligent transportation systems with wireless communication. The flow field would be robustly stable and efficient if the information on each vehicle's dynamics could be shared without time delay. However, a realistic situation inevitably entails some time delay, resulting from mechanical and control systems. The proposed model is validated by the neutral stability condition through linear stability theory, thus confirming that the proposed model substantially increases the stability of a traffic flow field compared with the conventional full velocity difference model (optimal velocity model). The modified Korteweg-de Vries equation is derived and analyzed for nonlinear analysis. A numerical simulation is also conducted to justify the proposed model. (C) 2021 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physa.2021.126437

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this paper, a new continuum traffic model is developed considering the backward-looking effect through a new positive backward equilibrium speed function. As compared with the conventional full velocity difference model, the backward equilibrium velocity function, which is largely acceptably grounded from mathematical and physical perspectives, plays an important role in significantly enhancing the stability of the traffic flow field. A linear stability condition is derived to demonstrate the flow neutralization capacity of the model, whereas the Korteweg-de Vries-Burgers equation and the attendant analytical solution are deduced using nonlinear analysis to observe the traffic flow behavior near the neutral stability condition. A numerical simulation, used to determine the flow stability enhancement efficiency of the model, is also conducted to verify the theoretical results.

DOI： 10.1007/s11071-021-06894-2

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Social norms have a profound influence on the perception of vaccination. People's attitudes toward vaccination reflect their inherent recognition of the trade-off between vaccine acceptance and risk of infection. Here we model a new path of cyclic epidemic dynamics in vaccination aspects by considering the vaccine acceptance and fear of infection, where the social dynamics are embedded into the mathematical epidemiological framework. Besides the already established vaccination game models, we develop a model called the cyclic mean-field (CMF) model vis-a-vis the cyclic behavioral (CBH) model. In the CMF model, we presume that, like disease transmission, the propelling process for vaccination also occurs through human contact, and the deflating vaccination (low vaccination acceptance) is also integrated into the social interactions of individuals. We analytically investigate the model framework through a rich phase diagram. Extensive numerical simulation suggests that effective vaccination may meaningfully reduce the community risk of infection. Provided a proactive attitude toward vaccination and fair recognition of disease risk can be developed, the vaccination uptake can be enhanced, thereby resulting in reduced epidemic prevalence. Our investigation might provide a new epidemiological dynamics concept that considers the social dynamics embedded into the alteration rate of vaccination. (C) 2021 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physa.2021.126230

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In the vaccination game, the spread of disease and the human decision-making to obtain pre-emptive vaccina-tions are coordinately united in successive seasons. This is backed both by epidemiological models, such as SIR, and by evolutionary game theory, assuming a given strategy-updating rule. Several rules have been proposed by the community and rely on either the imitation concept or the switching-action concept. The latter directly stipulates whether or not an agent commits to a course of action based on a rule, such as the aspiration concept. In contrast, the former borrowed its fundamental idea from the spatial version of a two-player, two-strategy (2 x 2) game, such as the spatial prisoner's dilemma (SPD). The pairwise Fermi (PW-Fermi) strategy has been heavily employed as the most representative idea. The present study modifies PW-Fermi, which consists of two processes: one for selecting a pairwise opponent to imitate and the other giving the probability of copying from the opponent. Instead of a random selection, our proposed model applies a stochastically skewed selection in which a neighbor who has a similar degree to the focal player is preferentially selected. This specific rule allows us to establish a quite efficient society, in which hub agents spontaneously obtain vaccination, but lower-degree agents do not. To this end, a small number of higher-degree agents, who are exposed to higher infection risk, are urged to be vaccinated, whereas many other agents enjoy free-riding. This produces a relatively small vaccination cost as a social sum and also effectively suppresses the spread of disease, resulting in a small disease cost for society as a whole.

DOI： 10.1016/j.biosystems.2021.104532

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Spirulina platensis has been considered a promising source of food supplement to combat malnutrition worldwide. Numerous investigations have stated its immune activity, ability to absorb CO2 during the growth period, and antioxidant potential. Well-known theoretical biomass kinetic model sheds are capable of qualitative analysis of the fast microalgae growth. In this regard, we considered eight popular biomass models: Monod, Haldane, Andrews & Noack, Teissier, Hinshelwood, Yano & Koga, Webb and, Aiba model comprising analytical investigation within the numerical simulation. Besides, in this study, we establish a new mathematical biomass growth model by merging the well-known Hinshelwood and Yano & Koga models. We explored the most suitable Spirulina growth model to minimize the overstated and understated growth trends in the assorted eight biomass kinetic models. Our findings show microalgae biomass growth and substrate diminishes along with time, and these results were compared with available experimental data. Results present a high value of R-2(0.9862), a low value of RSS (0.0813), AIC (-9.7277), and BIC (-8.2148) implied significantly fitted with the investigated data for the growth of Spirulina platensis compared with popular eight studied models.

DOI： 10.1016/j.heliyon.2021.e08185

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Do individuals enjoying a higher baseline payoff behave similarly in competitive scenarios compared to their counterparts? The classical replicator equation does not answer such a question since it is invariant to the background or baseline payoff of individuals. In reality, however, if one's baseline payoff is higher than the possible payoffs of an interaction (or game), the individual may respond generously or indifferently if s(he) is satisfied with the prevailing benchmark payoff. This work intends to explore such a phenomenon within the realm of pairwise interactions-taking the prisoner's dilemma as a metaphor-in well-mixed finite and infinite populations. In this framework, a player uses the payoff (comprising baseline and game payoffs) -expectation difference to estimate a degree of eagerness and, with that degree of eagerness, revises his or her strategy with a certain probability. We adopt two approaches to explore such a context, naming them as the Fermi and imitation processes, in which the former uses a pairwise Femi function and the latter considers the relative fitness to estimate probabilities for strategy revision. In a finite population, we examine the effect of intensities to payoff-expectation and strategic payoff differences (denoted by k1 and k2, respectively) as well as the level of contentment (omega) on the fixation probability and fixation time (for a single defector). We observe that the fixation probability surges with the increase of intensity parameters. Nevertheless, the maximum fixation probability may require a substantially larger time to fixate, especially when the expectation is lower than the baseline payoff. This means that cooperators can persist for a longer period of time. A higher expectation or greed, however, considerably reduces the fixation time. Interestingly, our numerical simulation reveals that both approaches are equivalent under weak k2(sigma< 1) in the Fermi process. We further derive mean-field equations for both approaches in the context of an infinite population, where we observe two possible evolutionary consequences: either full-scale defection or the persistence of the initial frequency of cooperators. The latter scenario indicates players' uninterested or neutral behavior in relation to the interaction due to their satisfaction on the baseline payoff.

DOI： 10.1103/PhysRevE.104.044314

記述言語：その他   掲載種別：研究論文（学術雑誌）  

In this paper, we discuss the theoretical interpretation of the artificial compressibility method (ACM) to propose a new explicit method for the unsteady numerical simulation of fluid flow. The proposed method employs the compressible continuity and Navier–Stokes equations, which facilitates the replacement of pressure as one of the major variables with density, theoretically backed by virtual particle concept. This new concept justifies the theoretical treatment assuming the speed of sound in ACM as a model parameter determined by the grid system. More importantly, the present method realizes, in a fully explicit manner, the solving of a set of equations, which prevents the solving of the Poisson equation of pressure. The new method was validated and proven by comparing the results of two-dimensional cavity flow between the proposed method, conventional incompressible method, and the Lattice–Boltzmann method with varying Reynolds numbers (100, 1000, and 10000). The results of the proposed method agree well with conventional and reference data for both steady-state and unsteady-state conditions, although slight numerical oscillations were observed for the proposed method at a Reynolds number of 10000. Thus, the numerical validation assures that the proposed method is an explicit method based on a solid theoretical ground to be a new efficient simulation framework.

DOI： 10.1016/j.jcp.2021.110524

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Feedback-evolving games characterize the interplay between the evolution of strategies and environments. Rich dynamics have been derived for such games under the premise of the replicator equation, which unveils persistent oscillations between cooperation and defection. Besides replicator dynamics, here we have employed aspiration dynamics, in which individuals, instead of comparing payoffs with opposite strategies, assess their payoffs by self-evaluation to update strategies. We start with a brief review of feedback-evolving games with replicator dynamics and then comprehensively discuss such games with aspiration dynamics. Interestingly, the tenacious cycles, as perceived in replicator dynamics, cannot be observed in aspiration dynamics. Our analysis reveals that a parameter -which depicts the strength of cooperation in enhancing the environment-plays a pivotal role in comprehending the dynamics. In particular, with the symmetric aspiration level, if replete and depleted states, respectively, experience Prisoner's Dilemma and Trivial games, the rich environment is achievable only when > 1. The case < 1 never allows us to reach the replete state, even with a higher cooperation level. Furthermore, if cooperators aspire less than defectors, then the enhanced state can be achieved with a relatively lower value compared with the opposite scenario because too much expectation from cooperation can be less beneficial.

DOI： 10.1098/rspa.2021.0240

記述言語：英語   掲載種別：研究論文（学術雑誌）  

With the aid of the evolutionary vaccination game on a scale-free network, we design a new subsidy policy, named degree dependent subsidy, where cooperative agents get incentives according to their connectivity or degree. That is, agents, having a greater degree, receive a higher incentive, and vice versa. Here we presume that vaccinators are cooperative agents. The new scheme can be said to an intermediate policy between two previously studies policies, namely free ticket and flat discount policies. The former policy distributes free tickets to cooperative hub agents as a priority, whereas the latter dispenses a fixed discount to every cooperator. We compare the efficiency of each policy in terms of having a less infectious state with a minimum social cost. While investigating the performance of the three policies in terms of average social payoff-which takes into account the cost of vaccination as well as infection-the free ticket scheme is found to be the most appealing policies among the three when the budget for subsidy is quite low. The degree dependent subsidy policy outperforms others for a moderate budget size, while the flat discount policy requires a higher budget to effectively suppress the disease. We further estimate threshold levels of the subsidy budget for each policy beyond which subsidizing results in excessive use of vaccination. As a whole, concerning vaccination coverage and final epidemic size, the degree-dependent subsidy scheme outperforms the flat discount scheme, but is dominated by the free ticket policy. (C) 2021 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jtbi.2021.110682

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In the midst of the COVID-19 pandemic, with limited or no supplies of vaccines and treatments, people and policymakers seek easy to implement and cost-effective alternatives to combat the spread of infection during the pandemic. The practice of wearing a mask, which requires change in people's usual behavior, may reduce disease transmission by preventing the virus spread from infectious to susceptible individuals. Wearing a mask may result in a public good game structure, where an individual does not want to wear a mask but desires that others wear it. This study develops and analyzes a new intervention game model that combines the mathematical models of epidemiology with evolutionary game theory. This approach quantifies how people use mask-wearing and related protecting behaviors that directly benefit the wearer and bring some advantage to other people during an epidemic. At each time-step, a suspected susceptible individual decides whether to wear a facemask, or not, due to a social learning process that accounts for the risk of infection and mask cost. Numerical results reveal a diverse and rich social dilemma structure that is hidden behind this mask-wearing dilemma. Our results highlight the sociological dimension of mask-wearing policy.

DOI： 10.1038/s41598-021-92094-2

記述言語：その他   掲載種別：研究論文（学術雑誌）  

This study characterizes the indoor airflow and occupants’ thermal sensations in a cross-ventilated building model sheltered by generic cube arrays based on large-eddy simulations (LESs). Four ventilation models, which comprise different cross-ventilating openings, streamwise (STR) and lateral (LAT) windows, and block arrangements, lattice-type square (SQ) and staggered (ST) patterns, were examined to understand the following geometry-oriented features: i) the temporal and spatial deviations of wind speed at openings and inside the ventilation models, ii) effects of time and space resolutions for the velocity data on the estimation accuracy of the ventilation rate, and iii) predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD) indices calculated with elaborately simulated velocity data. The difference in distribution of fluctuating normal velocity at openings was more significant when varying the conditions of the opening locations than that observed when varying the building arrangements. Therefore, the ventilation rates in the STR conditions were reasonably estimated using only the time-averaged flow rate at the center position of the windward opening; meanwhile, when the contributions of reverse flow were ignored at the openings, the ventilation rates in the LAT conditions were drastically underestimated using highly resolved velocity data at openings. Based on the thermal comfort assessment at an air temperature of 26°C, the discrepancies of area-averaged PMV values between STR and LAT cases were within 0.7 and 0.9 at the lower and middle heights of naturally ventilated buildings, resulting in a 5&#37; difference in the PPD values.

DOI： 10.1016/j.buildenv.2021.107811

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In the wake of the novel coronavirus, SARS-CoV-19, the world has undergone a critical situation in which grave threats to global public health emerged. Among human populations across the planet, travel restraints, border enforcement measures, quarantine, and isolation provisions were implemented to control and limit the spread of the contagion. Decisions on implementing and enforcing various control policies should be determined based on available real-world evidence and theoretical prediction. Further, countries around the globe-imposed force-quarantine and strict lockdown against the spreading could be unsustainable in the long run because of economic burden and people's frustration. This study proposes a novel exportation- importation epidemic model associated with behavioral dynamics under the evolutionary game theory by considering the two-body system: a source country of a contagious disease and a neighboring disease-free state. The model is first applied to the original COVID-19 data in China, Italy, and the Republic of Korea (ROK) and observed through consistent fitting results with equivalent goodness-of-fit. Then, the data are estimated per the appropriate parameters. Driven by these parametric settings and considering the normalized population, the numerical analysis, and epidemiological exploration, this work further elucidates the substantial impact of quarantine policies, healthcare facilities, socio-economic cost, and the public counter-compliance effect. Extensive numerical analysis shows that funds spent on the individual level as "emergency relief-package" can reduce the infection and improve quarantine policy success. Our results also explore that controlling border measurement can work well in the final epidemic stage of disease only if the cost is low. (C) 2021 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2021.110918

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The difference between conventional replicator dynamics and pairwise (PW) nonlinear Fermi dynamics can be discerned by studying the evolutionary dynamics of the interactions between the symmetric cyclic structure in the rock-paper-scissors game and interand intraspecific competitions. Often, conventional replicator models presume that the payoff difference among species is a linear function (a linear benefit). This study introduces a PW contrast under the properties of the well-known Fermi rule, where species play against one another in pairs. To model a PW nonlinear evolutionary environment (a nonlinear benefit) within this framework, both analytical and numerical approaches are applied. It is determined that the dynamics of the linear and nonlinear benefits can present the same stability conditions at equilibrium. Moreover, it is also demonstrated that, even in an identical equilibrium condition for both dynamics, the numerical result run by a deterministic approach presents a faster stability state for nonlinear benefit dynamics. This study also suggests that introducing mutation as demographic noise can effectively disrupt the phase regions and show the different relationships between linear and nonlinear dynamics. The symmetric bidirectional mutation among all the species reduced to the stable limit cycle by an arbitrary small mutation rate is also explored. Due to the environmental noise, however, linear and nonlinear exhibit the same steady state. Nevertheless, non-linearity illustrates more stable and faster stability situations. Our result suggests that environmental and demographic noise on the evolutionary dynamic framework can serve as a mechanism for supporting PW nonlinear dynamics in multi-species games. (C) 2020 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.amc.2020.125767

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In 2019, Bangladesh has grappled with a record-breaking surge in dengue fever, experiencing the highest number of dengue cases since the year 2000. Together, the intensification of dengue fever combined with a lack of dengue vaccines and appropriate medicines is expected to further the public and government’s interests in appropriate and potential dengue vaccines to control the epidemic. We considered people’s characteristics, dengue experience, and knowledge to assess their willingness-to-accept (WTA) and willingness-to-pay (WTP) for a hypothetical dengue vaccine and ex-post treatment in Bangladesh (June–July 2019). This study implemented a contingent valuation (CV) method with 3,251 respondents in 10 different locations of Bangladesh. All respondents participated in a hypothetical dengue vaccine scenario consisting of 65&#37; (vaccine A), 80&#37; (vaccine B), and 95&#37; (vaccine C) effectiveness levels with three doses of each vaccine and ex-post dengue treatment. Around 71.2&#37; of respondents were willing to pay for at least one of the hypothetical vaccines: A, B, or C. The average WTPs of the three vaccines amounted to US&#36; 47.0, US&#36; 66.0, and US&#36; 89.0, which were defined as the total cost of the doses necessary to obtain immunity. In Bangladesh, there is a significant demand for low-priced dengue vaccines, which was proven by people’s higher acceptance of vaccination practices. Though dengue vaccines are not yet available in Bangladesh, this study provides significant support that both the government and private sectors should work together to develop a reliable and affordable dengue vaccine.

DOI： 10.1080/21645515.2020.1796424

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We introduce a new spatial prisoner's dilemma (SPD) model in which the so-called network reciprocity is enhanced more than in the conventional model. In addition to the usual binary strategies-perfect cooperator and perfect defector-we introduce "fence-sitters", who either cooperate or defect with equal probability, as a third strategy. In regions with larger Stag-Hunt-type dilemmas but smaller Chicken-type dilemmas, the existence of the fence-sitters works as a buffer, hampering the exploitation of cooperators by neighboring defectors and significantly enhancing the cooperative phase. Conversely, in regions with larger Chicken-type dilemmas but smaller Stag-Hunt-type dilemmas, the existence of the fence-sitters expands the critical dilemma strength for the survival of cooperation, but it reduces the cooperating fraction more than in the conventional model. What we have found may justify the conclusion that the existence of people with neutral opinions-often regarded betwixt and between-absorbs the severe competition between two extreme groups, bringing a more accommodationist situation to our society, backed with greater cooperation. (C) 2020 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.amc.2020.125624

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A co-evolutionary model of both network and mixed strategy is proposed in this study. The assigned strategy s(i) of agent i is defined by a real number ranging from 0 to 1, which probabilistically ordains a subsequent action of either cooperation or defection as the agent's offer. We assume a network dynamic to support or hamper the enhancement of cooperation, where an agent severs a link with the neighbor who has the most disassortative strategy. This means that an agent tends to maintain interactions only with neighbors that resemble the agent. A series of numerical simulations reveal that our "assortative grouping" framework enhances cooperation. Interestingly, when a low network adaptation speed and a certain degree of strategy copy error are presumed, phenomenal network heterogeneity evolves, one that realizes more significant cooperation as compared to error-free cases. (C) 2020 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2020.110603

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Forecasting the dynamics of flu epidemics could be vital for policy-making concerning the allocation of public health resources. Reliable predictions about disease transmission networks also help fix the benchmark for reconciling diverse aspects to the decision-makers while selecting and implementing a suitable health intervention. To this aim, we propose an SIR/V M epidemic game model to reveal the dynamic evolution of intervention policies, entangling social feedbacks, behavioral responses, and viral transmission on several network topologies into a single framework. Besides vaccination, this study introduces intermediate defense measures (IDM) as an alternative provision to restraint the epidemic resurgence in structured and unstructured populations. Although heterogeneity is a commonly observed phenomenon in human populations, many antecedent studies typically preferred homogenous networks. Here, we investigate the disparities found in epidemic diffusion within homogeneous and heterogeneous networks, employing a mean-field approximation and multi-agent simulation, respectively. Additionally, we explore both network types simultaneously and justify their potential impacts on control provisions' success. As a general tendency, vaccination and IDM complement each other within the entire parametric regions. Our study elucidates the coexistence of multiple policies as well as the abrupt emergence of stain points adopting several network topologies. A careful investigation on stain points reveals that hub agents solely rely on free-riding brings the endemic state of an epidemic, triggered by a sudden extinction of vaccinators and self-protectors. The emergence of too many self-interested people spoils the herd immunity state and initiates the outbreaks, heavily observed in well-mixed and scale-free networks. On the other hand, the coexistence of policies occurs mostly in the networks mentioned above but rarely seen in the lattice network. The robustness of the proposed model has been tested by adding mean-field theoretical results for a nonspatial population and agent-based simulated outcomes for spatial populations under a wide variety of parametric conditions. Model outcomes confirm that the game-payoff regulates the epidemic dynamics, while the epidemic propagation governs individuals' health status. Moreover, we expose a complex interplay between cost and efficacy of control provisions and justify keeping the provisional costs reasonably lower would be an ultimate challenge to maintain disease attenuation. The central theme of this paper is thus to portray the holistic summary of epidemic prevalence and the relative contribution of each intervention to epidemic remission.(c) 2020 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2020.110584

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We successfully establish a theoretical framework of pairwise approximation for the vaccination game in which both the dynamic process of epidemic spread and individual actions in helping prevent social behaviours are quantitatively evaluated. In contrast with mean-field approximation, our model captures higher-order effects from neighbours by using an underlying network that shows how the disease spreads and how individual decisions evolve over time. This model considers not only imperfect vaccination but also intermediate protective measures other than vaccines. Our analytical predictions are validated by multi-agent simulation results that estimate random regular graphs at varying degrees.

DOI： 10.1098/rspa.2020.0769

記述言語：英語   掲載種別：研究論文（学術雑誌）  

As protection against infectious disease, immunity is conferred by one of two main defense mechanisms, namely (i) resistance generated by previous infection (known as natural immunity) or (ii) by being vaccinated (known as artificial immunity). To analyze, a modified SVIRS epidemic model is established that integrates the effects of the durability of protection and imperfectness in the framework of the human decision-making process as a vaccination game. It is supposed that immunized people become susceptible again when their immunity expires, which depends on the duration of immunity. The current theory for most voluntary vaccination games assumes that seasonal diseases such as influenza are controlled by a temporal vaccine, the immunity of which lasts for only one season. Also, a novel perspective is established involving an individual's immune system combined with self-interest to take the vaccine and natural immunity obtained from infection by coupling a disease-spreading model with an evolutionary game approach over a long period. Numerical simulations show that the longer attenuation helps significantly to control the spread of disease. Also discovered is the entire mechanism of active and passive immunities, in the sense of how they coexist with natural and artificial immunity. Thus, the prospect of finding the optimal strategy for eradicating a disease could help in the design of effective vaccination campaigns and policies. (C) 2020 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jtbi.2020.110531

記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/6622876

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CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In the context of voluntary vaccination, we consider two additional provisions as well as pre-emptive vaccination for a unified model over epidemiology and evolutionary game theory to assess the extent to which advanced and late provisions restrict the spread of disease. To circumvent infection, people can be vaccinated pre-emptively before the epidemic season, but the imperfectness of vaccination or an unwillingness to be vaccinated may cause people instead to either be late-vaccinated or use self-protection. Here, self-protection corresponds to actions such as wearing a mask, washing hands, or using a mosquito net and is defined as the third strategy after pre-emptive vaccination (the first strategy) and late-vaccination (the second strategy). Our model can reproduce multiple social dilemma situations resulting from what is known as the vaccination dilemma (originating from preemptive vaccination), which works on a global time scale (i.e., repeated seasons approaching social equilibrium), and also from two other dilemmas due to late provisions, which work on a local time scale (i.e., every time step in a single season). To reproduce how an individual can acquire information for adaptation from neighbors or the society for a suitable provision, we introduce several strategy-updating rules for both global and local time scales and this behavioral feedback has a significant effect to reducing a transmissible disease. We also establish the social efficiency deficit (SED) indicator for a triple-dilemma game to quantify the existence of a social dilemma. Relying fully on a theoretical framework, our model provides a new perspective for evaluations: (i) how much more advantageous and effective pre-emptive vaccination is in eradicating a communicable disease compared with late provisions such as late vaccination and selfprotection, and (ii) the extent of the social dilemma resulting from each of the three provisions, given the new idea of SED. The main effect of the triple-dilemma is that expensive provision displays no SED (no dilemma) until the efficiency or effectiveness of provisions reaches a certain level. (C) 2020 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jtbi.2020.110399

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Records of epidemics acknowledge immunological multi-serotype illnesses as an important aspect of the occurrence and control of contagious diseases. These patterns occur due to antibody-dependent-enhancement (ADE) among serotype diseases, which leads to infection of secondary infectious classes. One example of this is dengue hemorrhagic fever and dengue shock syndrome, which comprises the following four serotypes: DEN-1, DEN-2, DEN-3, and DEN-4. The evolutionary vaccination game approach is able to shed light on this long-standing issue in a bid to evaluate the success of various control programs. Although immunization is regarded as one of the most accepted approaches for minimizing the risk of infection, cost and efficiency are important factors that must also be considered. To analyze the n-serovar aspect alongside ADE consequence in voluntary vaccination, this study establishes a new mathematical epidemiological model that is dovetailed with evolutionary game theory, an approach through which we explored two vaccine programs: primary and secondary. Our findings illuminate that the 'costefficiency' effect for vaccination decision exhibits an impact on controlling n-serovar infectious diseases and should be designed in such a manner as to avoid adverse effects. Furthermore, our numerical result justifies the fact that adopting ADE significantly boosted emerging disease incidence, it also suggest that the joint vaccine policy works even better when the complex cyclical epidemic outbreak takes place among multi serotypes interactions. Research also exposes that the primary vaccine is a better controlling tool than the secondary; however, introducing a highly-efficiency secondary vaccine against secondary infection plays a key role to control the disease prevalence. (C) 2020 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jtbi.2020.110379

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In line with more enhanced network reciprocity, we built a new spatial prisoner's dilemma (SPD) game considering conformity with presumption of lattice for underlying network and pairwise Fermi (PW-Fermi) for update rule. The key protocol is that a neighbor with more weight resulting from the conformity would be more likely selected as a pairwise opponent in the PW-Fermi updating process instead of random selection the conventional model presuming. A series of systematic simulations confirms that our model realizes more enhanced network reciprocity than the conventional SPD model. We elucidated its mechanism by means of considering on the concept of END period (meaning an initial period in which the global-cooperation fraction decreases from its initial value) and EXP periods (meaning the period following to END period in which global-cooperation increases) that substantially explaining how cooperative clusters survive in initial period and extend to defective zones afterwards. (C) 2020 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2020.109997

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A new cellular automata traffic model based on the revised S-NFS model was established to consider a mixed flow of automated and human-driven vehicles assuming a multi-lane system. The model further classified automated vehicles into two categories: (1) vehicles with adaptive cruise control and (2) those with cooperative adaptive cruise control that supports so-called platoon driving. A vehicle that favors maximizing individual payoff, which ensures minimizing its own travel time, while maximizing global traffic flux was expected as the entire society. Intensive simulations, wherein automated and human driven vehicles were presumed as cooperative (C) and defective (D) strategies, respectively, revealed that a D-strategy is always better than a C-strategy to maximize individual payoff as long as a smaller cooperative fraction is imposed. Meanwhile, social optimal could be realized by a situation comprising only automated vehicles. Such a stag-hunt social dilemma implied that an automated vehicle control system (AVCS) cannot permeate into a population of human-driven vehicles if the dissemination stage starts from a single vehicle with an AVCS. (c) 2020 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2020.109861

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Imitation and aspiration update rules are frequently observed in human and animal populations. While the imitation process entails payoff comparisons with surroundings, the aspiration process refers to self-evaluation. This work explores the evolution of cooperation in dyadic games under the coexistence of these two dynamics in an infinitely large well-mixed population. Two situations have been explored: (i) individuals adopt either an imitation or aspiration update rule with a certain probability, and (ii) the entire population is divided into two groups where one group only uses imitative rules and the other obeys aspiration updating alone. Both premises have been modeled by taking an infinite approximation of the finite population. In particular, the second mixing principle follows an additive property: the outcome of the whole population is the weighted average of outcomes from imitators and aspiration-driven individuals. Our work progressively investigates several variants of aspiration dynamics under strong selection, encompassing symmetric, asymmetric, and adaptive aspirations, which then coalesce with imitative dynamics. We also demonstrate which of the update rules performs better, under different social dilemmas, by allowing the evolution of the preference of update rules besides strategies. Aspiration dynamics always outperform imitation dynamics in the prisoner's dilemma, however, in the chicken and stag-hunt games the predominance of either update rule depends on the level of aspirations as well as on the extent of greed and fear present in the system. Finally, we examine the coevolution of strategies, aspirations, and update rules which leads to a binary state of obeying either imitation or aspiration dynamics. In such a circumstance, when aspiration dynamics prevail over imitation dynamics, cooperators and defectors coexist to an equal extent.

DOI： 10.1103/PhysRevE.102.032120

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The unprecedented global spread of COVID-19 has prompted dramatic public-health measures like strict stay-at-home orders and economic shutdowns. Some governments have resisted such measures in the hope that naturally acquired shield immunity could slow the spread of the virus. In the absence of empirical data about the effectiveness of these measures, policymakers must turn to epidemiological modelling to evaluate options for responding to the pandemic. This paper combines compartmental epidemiological models with the concept of behavioural dynamics from evolutionary game theory (EGT). This innovation allows us to model how compliance with an economic lockdown might wane over time, as individuals weigh the risk of infection against the certainty of the economic cost of staying at home. Governments can, however, increase spending on social programmes to mitigate the cost of a shutdown. Numerical analysis of our model suggests that emergency-relief funds spent at the individual level are effective in reducing the duration and overall economic cost of a pandemic. We also find that shield immunity takes hold in a population most easily when a lockdown is enacted with relatively low costs to the individual. Our qualitative analysis of a complex model provides evidence that the effects of shield immunity and economic shutdowns are complementary, such that governments should pursue them in tandem.

DOI： 10.1098/rsos.201095

記述言語：英語   掲載種別：研究論文（学術雑誌）  

What do corruption, resource overexploitation, climate inaction, vaccine hesitancy, traffic congestion, and even cancer metastasis have in common? All these socioeconomic and sociobiological phenomena are known as social dilemmas because they embody in one form or another a fundamental conflict between immediate self-interest and long-term collective interest. A shortcut to the resolution of social dilemmas has thus far been reserved solely for highly stylised cases reducible to dyadic games (e.g., the Prisoner's Dilemma), whose nature and outcome coalesce in the concept of dilemma strength. We show that a social efficiency deficit, measuring an actor's potential gain in utility or fitness by switching from an evolutionary equilibrium to a social optimum, generalises dilemma strength irrespective of the underlying social dilemma's complexity. We progressively build from the simplicity of dyadic games for which the social efficiency deficit and dilemma strength are mathematical duals, to the complexity of carcinogenesis and a vaccination dilemma for which only the social efficiency deficit is numerically calculable. The results send a clear message to policymakers to enact measures that increase the social efficiency deficit until the strain between what is and what could be incentivises society to switch to a more desirable state.

DOI： 10.1038/s41598-020-72971-y

記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/4842514

Scopus

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Game theory has been extensively applied to elucidate the evolutionary mechanism of cooperative behaviour. Dilemmas in game theory are important elements that disturb the promotion of cooperation. An important question is how to escape from dilemmas. Recently, a dynamic utility function (DUF) that considers an individual's current status (wealth) and that can be applied to game theory was developed. The DUF is different from the famous five reciprocity mechanisms called Nowak's five rules. Under the DUF, cooperation is promoted by poor players in the chicken game, with no changes in the prisoner's dilemma and stag-hunt games. In this paper, by comparing the strengths of the two dilemmas, we show that the DUF is a novel reciprocity mechanism (sixth rule) that differs from Nowak's five rules. We also show the difference in dilemma relaxation between dynamic game theory and (traditional) static game theory when the DUF and one of the five rules are combined. Our results indicate that poor players unequivocally promote cooperation in any dynamic game. Unlike conventional rules that have to be brought into game settings, this sixth rule is universally (canonical form) applicable to any game because all repeated/evolutionary games are dynamic in principle.

DOI： 10.1098/rsos.200891

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Vaccinating decisions can be influenced by imitation as well as self-evaluation or aspiration. This work analyses vaccinating behaviours by coupling both imitation and aspiration update rules, adopting an existing set-up of the mean-field vaccination game. We incorporate the imitation mechanism with several variants of the aspiration protocol, encompassing constant and adaptive aspirations. Equations of the combined dynamics have been derived by grouping the population according to (i) vaccinating strategies and (ii) healthy and infected status within each strategy. If aspiration levels are fixed but differentiated by vaccinating strategies, then vaccinators aspiring less than non-vaccinators are found to ameliorate the vaccination coverage, thereby yielding a less infectious state. The adaptive aspirations maintain a positive correlation with the vaccine efficacy while keeping the opposite relation with vaccination cost. When vaccinating strategies, aspirations and update rules are allowed to evolve synchronously, then either the imitation or aspiration process takes over the entire population. If aspiration rules prevail, then vaccinees and non-vaccinees coexist equally (according to (i)) or vaccine uptake follows a non-monotonic trend with the efficacy (according to (ii)). The imitative rule performs better when vaccination is less expensive or cheap, while aspiration updating safeguards the tenacity of vaccinees despite vaccination being expensive.

DOI： 10.1098/rspa.2020.0327

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this work, by drawing a RAD-GID phase-plane diagram for pair-wise games, we prove that these five rules are indeed quite different for the resolution (relaxation) of the two dilemmas.

DOI： 10.1098/rsos.200943

記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/4793625

Scopus

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Limiting the analysis to the so-called prisoner's dilemma situation, a new framework of 3-strategy game is proposed herein by adding a costly cooperative loner (CL) to the original strategies; cooperator and defector. Relaying on the replicator dynamics that presumes an infinite and well-mixed population, a set of equilibria is deliberately drawn. In contrast to the expectations from this study, the introduction of CL did not substantially alter the evolutionary trails and always ended with all-defectors state. Some arguments on why such counter-intuitive result comes about is are discussed. The outcomes are justified by the CL's dependency on the other two strategic types and the reduced power in foiling defectors compared to the paradigmatic costly punisher model. (C) 2019 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.amc.2019.124889

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Limiting the analysis to the so-called prisoner's dilemma situation, a new framework of 3-strategy game is proposed herein by adding a costly cooperative loner (CL) to the original strategies; cooperator and defector. Relaying on the replicator dynamics that presumes an infinite and well-mixed population, a set of equilibria is deliberately drawn. In contrast to the expectations from this study, the introduction of CL did not substantially alter the evolutionary trails and always ended with all-defectors state. Some arguments on why such counter-intuitive result comes about is are discussed. The outcomes are justified by the CL's dependency on the other two strategic types and the reduced power in foiling defectors compared to the paradigmatic costly punisher model.

DOI： 10.1016/j.amc.2019.124889

記述言語：その他   掲載種別：研究論文（学術雑誌）  

The aim of this study is to verify whether a human can detect the social dilemma class and its strength for four various games: Prisoner’s dilemma, Trivial, Chicken, and Stag-Hunt by using a web-based structural cross-sectional survey. We considered respondent’s cooperative and defective behavior by designing multiple sets of 2 × 2 games for two classes in terms of game opponents: whether he is an intimate friend or an unknown person in the questionnaire. In total, 375 respondents participated in this survey. We found that Prisoner’s dilemma and Trivial game are recognized easily by the respondents, but they are not aware of the dilemma strength and difference of game opponent’s attribute whether the opponent is a close or unknown person.

DOI： 10.5109/2740936

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We propose a mean-field vaccination game framework that combines two distinct processes: the simultaneous spreading of two strains of an influenza-like disease, and the adoption of vaccination based on evolutionary game theory presuming an infinite and well-mixed population. The vaccine is presumed to be imperfect such that it shows better efficacy against the original (resident) strain rather than the new one (mutant). The vaccination-decision takes place at the beginning of an epidemic season and depends upon the vaccine-effectiveness along with the cost. Additionally, we explore a situation if the original strain continuously converts to a new strain through the process of mutation. With the aid of numerical experiments, we explore the impact of vaccinating behavior on a specific strain prevalence. Our results suggest that the emergence of vaccinators can create the possibility of infection-prevalence of the new strain if the vaccine cannot bestow a considerable level of efficiency against that strain. On the other hand, the resident strain can continue to dominate under large-scale vaccine avoidance. Moreover, in the case of continuous mutation, the vaccine efficacy against the new strain plays a pivotal role to control the disease prevalence. We successfully obtain phase diagrams, displaying the infected fraction with each strain, final epidemic size, vaccination coverage, and average social payoff considering two-different strategy-update rules and provide a comprehensive discussion to get an encompassing idea, justifying how the vaccinating behavior can affect the spread of a disease having two strains.

DOI： 10.1088/1742-5468/ab74c6

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Outbreaks of repeated pandemics and heavy epidemics are daunting threats to human life. This study aims at investigating the dynamics of disease conferring temporary or waning immunity with several forced-control policies aided by vaccination game theory. Considering an infinite and well-mixed homogenous population, our proposed model further illustrates the significance of introducing two well-known forced control techniques, namely, quarantine and isolation, in order to model the dynamics of an infectious disease that spreads within a human population where pre-emptive vaccination has partially been taken before the epidemic season begins. Moreover, we carefully examine the combined effects of these two types (pre-emptive and forced) of protecting measures using the SEIR-type epidemic model. An in-depth investigation based on evolutionary game theory numerically quantifies the weighing impact of individuals' vaccinating decisions to improve the efficacy of forced control policies leading up to the relaxation of the epidemic spreading severity. A deterministic SVEIR model, including vaccinated (V) and exposed (E) states, is proposed having no spatial structure while implementing these intervention techniques. This study uses a mixed control strategy relying on quarantine and isolation policies to quantify the optimum requirement of vaccines for eradicating disease prevalence completely from human societies. Furthermore, our theoretical study justifies the fact that adopting forced control policies significantly reduces the required level of vaccination to suppress emerging disease prevalence, and it also confirms that the joint policy works even better when the epidemic outbreak takes place at a higher transmission rate. Research reveals that the isolation policy is a better disease attenuation tool than the quarantine policy, especially in endemic regions where the disease progression rate is relatively higher. However, a meager progression rate gradually weakens the speed of an epidemic outbreak and, therefore, applying a moderate level of control policies is sufficient to restore the disease-free state. Essentially, positive measures (pre-emptive vaccination) regulate the position of the critical line between two phases, whereas exposed provisions (quarantine or isolation) are rather dedicated to mitigating the disease spreading in endemic regions. Thus, an optimal interplay between these two types of intervention techniques works remarkably well in attenuating the epidemic size. Despite having advanced on the development of new vaccines and control strategies to mitigate epidemics, many diseases like measles, tuberculosis, Ebola, and flu are still persistent. Here, we present a dynamic analysis of the SVEIR model using mean-field theory to develop a simple but efficient strategy for epidemic control based on the simultaneous application of the quarantine and isolation policies.

DOI： 10.1088/1742-5468/ab75ea

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A modified susceptible-vaccinated-infected-recovered (SIR/V) with unaware-aware (UA) epidemic model in heterogeneous networks is presented to study the effect of information spreading in the spatial structure of the vaccination game on epidemic dynamics. Two layers SIR/V epidemic model is considered to elucidate information spreading, where the fraction of susceptible, vaccinated and infected individuals are parted as unaware and aware state as each susceptible and vaccinated persons are allied with their infected neighbors by a spatial structure, say, an underlying network. The context deduces epidemic vaccination game with awareness influence dynamics in one single season followed by a strategy update process that refer an individual to take imperfect vaccination or not. We considered two different strategy updating rules: individual based risk assessment (IB-RA) and strategy-based risk assessment (SB-RA) to explore how different underlying network topologies, say, random graph and scale free networks, subsequently giving impact on the final epidemic size, vaccination coverage and average social payoff through the effect of information spreading on epidemic. Thus, it can be seen that, awareness can enhance the epidemic threshold effectiveness and lessen the spreading of infection in a scale free network other than random graph and homogeneous network. (C) 2019 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2019.109548

記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

DOI： 10.5109/6781026

Scopus

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We propose a mean-field vaccination game framework that combines two distinct processes: The simultaneous spreading of two strains of an influenza-like disease, and the adoption of vaccination based on evolutionary game theory presuming an infinite and well-mixed population. The vaccine is presumed to be imperfect such that it shows better efficacy against the original (resident) strain rather than the new one (mutant). The vaccination-decision takes place at the beginning of an epidemic season and depends upon the vaccine-effectiveness along with the cost. Additionally, we explore a situation if the original strain continuously converts to a new strain through the process of mutation. With the aid of numerical experiments, we explore the impact of vaccinating behavior on a specific strain prevalence. Our results suggest that the emergence of vaccinators can create the possibility of infection-prevalence of the new strain if the vaccine cannot bestow a considerable level of efficiency against that strain. On the other hand, the resident strain can continue to dominate under large-scale vaccine avoidance. Moreover, in the case of continuous mutation, the vaccine efficacy against the new strain plays a pivotal role to control the disease prevalence. We successfully obtain phase diagrams, displaying the infected fraction with each strain, final epidemic size, vaccination coverage, and average social payoff considering two-different strategy-update rules and provide a comprehensive discussion to get an encompassing idea, justifying how the vaccinating behavior can affect the spread of a disease having two strains. Highlights-We build a mean-field vaccination game scheme to analyze the effect of an imperfect vaccine on a two-strain epidemic spreading taking into account individuals' vaccination behavior.-En masse vaccine avoidance can enhance the possibility of the original strain prevalence.-Propensity for vaccination can create the possibility of infection by the new strain if the vaccine is unable to provide a considerable level of efficiency against that strain.

DOI： 10.1088/1742-5468/ab74c6

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The aim of this study is to verify whether a human can detect the social dilemma class and its strength for four various games: Prisoner’s dilemma, Trivial, Chicken, and Stag-Hunt by using a web-based structural cross-sectional survey. We considered respondent’s cooperative and defective behavior by designing multiple sets of 2 × 2 games for two classes in terms of game opponents: whether he is an intimate friend or an unknown person in the questionnaire. In total, 375 respondents participated in this survey. We found that Prisoner’s dilemma and Trivial game are recognized easily by the respondents, but they are not aware of the dilemma strength and difference of game opponent’s attribute whether the opponent is a close or unknown person.

DOI： 10.5109/2740936

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A modified susceptible-vaccinated-infected-recovered (SIR/V) with unaware-aware (UA) epidemic model in heterogeneous networks is presented to study the effect of information spreading in the spatial structure of the vaccination game on epidemic dynamics. Two layers SIR/V epidemic model is considered to elucidate information spreading, where the fraction of susceptible, vaccinated and infected individuals are parted as unaware and aware state as each susceptible and vaccinated persons are allied with their infected neighbors by a spatial structure, say, an underlying network. The context deduces epidemic vaccination game with awareness influence dynamics in one single season followed by a strategy update process that refer an individual to take imperfect vaccination or not. We considered two different strategy updating rules: individual based risk assessment (IB-RA) and strategy-based risk assessment (SB-RA) to explore how different underlying network topologies, say, random graph and scale free networks, subsequently giving impact on the final epidemic size, vaccination coverage and average social payoff through the effect of information spreading on epidemic. Thus, it can be seen that, awareness can enhance the epidemic threshold effectiveness and lessen the spreading of infection in a scale free network other than random graph and homogeneous network.

DOI： 10.1016/j.chaos.2019.109548

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Outbreaks of repeated pandemics and heavy epidemics are daunting threats to human life. This study aims at investigating the dynamics of disease conferring temporary or waning immunity with several forced-control policies aided by vaccination game theory. Considering an infinite and well-mixed homogenous population, our proposed model further illustrates the significance of introducing two well-known forced control techniques, namely, quarantine and isolation, in order to model the dynamics of an infectious disease that spreads within a human population where pre-emptive vaccination has partially been taken before the epidemic season begins. Moreover, we carefully examine the combined effects of these two types (pre-emptive and forced) of protecting measures using the SEIR-type epidemic model. An in-depth investigation based on evolutionary game theory numerically quantifies the weighing impact of individuals' vaccinating decisions to improve the efficacy of forced control policies leading up to the relaxation of the epidemic spreading severity. A deterministic SVEIR model, including vaccinated (V) and exposed (E) states, is proposed having no spatial structure while implementing these intervention techniques. This study uses a mixed control strategy relying on quarantine and isolation policies to quantify the optimum requirement of vaccines for eradicating disease prevalence completely from human societies. Furthermore, our theoretical study justifies the fact that adopting forced control policies significantly reduces the required level of vaccination to suppress emerging disease prevalence, and it also confirms that the joint policy works even better when the epidemic outbreak takes place at a higher transmission rate. Research reveals that the isolation policy is a better disease attenuation tool than the quarantine policy, especially in endemic regions where the disease progression rate is relatively higher. However, a meager progression rate gradually weakens the speed of an epidemic outbreak and, therefore, applying a moderate level of control policies is sufficient to restore the disease-free state. Essentially, positive measures (pre-emptive vaccination) regulate the position of the critical line between two phases, whereas exposed provisions (quarantine or isolation) are rather dedicated to mitigating the disease spreading in endemic regions. Thus, an optimal interplay between these two types of intervention techniques works remarkably well in attenuating the epidemic size. Despite having advanced on the development of new vaccines and control strategies to mitigate epidemics, many diseases like measles, tuberculosis, Ebola, and flu are still persistent. Here, we present a dynamic analysis of the SVEIR model using mean-field theory to develop a simple but efficient strategy for epidemic control based on the simultaneous application of the quarantine and isolation policies. Highlights • This model incorporates the elements of mathematical epidemiology and a vaccination game into a single framework. • A dynamical analysis of the SEIR/V epidemic model equipped with quarantine and isolation policies is introduced. • The proposed game-theoretic framework rigorously addresses real situations when control policies are adopted simultaneously as well as separately. • Adopting control policies can significantly reduce the required level of vaccination to suppress disease prevalence. • A joint policy seems impressive when an epidemic outbreak takes place at a higher transmission rate. • For a smaller basic reproduction number, the quarantine policy outperforms the isolation policy.

DOI： 10.1088/1742-5468/ab75ea

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A Multi Agent Simulation (MAS) model that joins evolutionary game theory with epidemiological dynamics is established. Various subsidy policies that encourage vaccination are evaluated quantitatively with the model. The underlying social network topology is based on a scale-free network. Individual subsidies for vaccinations can be directed to hub agents with priority, to efficiently suppress the overall social cost of a vaccination program. These hub agents are more likely to spread both knowledge about vaccination and the disease in question. Our comprehensive simulations showed that this intuitively appealing strategy cannot be effective if the vaccination cost is low and the vaccination budget is small. Thus, we find that the hub agent priority strategy is not always effective. (C) 2019 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jtbi.2019.110059

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A Multi Agent Simulation (MAS) model that joins evolutionary game theory with epidemiological dynamics is established. Various subsidy policies that encourage vaccination are evaluated quantitatively with the model. The underlying social network topology is based on a scale-free network. Individual subsidies for vaccinations can be directed to hub agents with priority, to efficiently suppress the overall social cost of a vaccination program. These hub agents are more likely to spread both knowledge about vaccination and the disease in question. Our comprehensive simulations showed that this intuitively appealing strategy cannot be effective if the vaccination cost is low and the vaccination budget is small. Thus, we find that the hub agent priority strategy is not always effective.

DOI： 10.1016/j.jtbi.2019.110059

記述言語：英語   掲載種別：研究論文（学術雑誌）  

© 2019 Elsevier Ltd Evaporative cooling is a well-known passive technique adopted especially in hot and dry climatic regions. This paper presents a simplified numerical model to assess the impact of water spray over roof surfaces on the building thermal load. First, we performed a series of long-term outdoor measurements of heat fluxes from an asphalt pavement and roof top of a laboratory building waterproofed by asphalt sheet. Based on the measured data, a correlation is proposed to estimate the evaporation rate of the concerned surfaces after rain showers. A simplified numerical model is then developed using this correlation based on the unsteady heat transfer to analyze the effect of precipitation and artificial water spray on the roof of the laboratory building. Simulation is performed with the help MATLAB using the hourly weather data from Fukuoka, Japan, and the simulated results are found to be in correspondence with the measured data. Finally, the cooling effect achieved by varying the amount and rate of water spray over the roof is compared to find out the optimum spraying conditions. The novelty of this study is that, in this model, the evaporation rate can be expressed in terms of the evaporation ratio, which is defined as a function of the water content of the surface layer of the roof. The water content of the surface layer can be obtained by the water balance equation, which is coupled dynamically with conductive equations. This procedure can drastically reduce the calculation load compared to the conventionally applied simultaneous hygrothermal transfer equation.

DOI： 10.1016/j.applthermaleng.2019.114514

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Evaporative cooling is a well-known passive technique adopted especially in hot and dry climatic regions. This paper presents a simplified numerical model to assess the impact of water spray over roof surfaces on the building thermal load. First, we performed a series of long-term outdoor measurements of heat fluxes from an asphalt pavement and roof top of a laboratory building waterproofed by asphalt sheet. Based on the measured data, a correlation is proposed to estimate the evaporation rate of the concerned surfaces after rain showers. A simplified numerical model is then developed using this correlation based on the unsteady heat transfer to analyze the effect of precipitation and artificial water spray on the roof of the laboratory building. Simulation is performed with the help MATLAB using the hourly weather data from Fukuoka, Japan, and the simulated results are found to be in correspondence with the measured data. Finally, the cooling effect achieved by varying the amount and rate of water spray over the roof is compared to find out the optimum spraying conditions. The novelty of this study is that, in this model, the evaporation rate can be expressed in terms of the evaporation ratio, which is defined as a function of the water content of the surface layer of the roof. The water content of the surface layer can be obtained by the water balance equation, which is coupled dynamically with conductive equations. This procedure can drastically reduce the calculation load compared to the conventionally applied simultaneous hygrothermal transfer equation.

DOI： 10.1016/j.applthermaleng.2019.114514

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The dynamics of a spreadable disease are largely governed by four factors: proactive vaccination, retroactive treatment, individual decisions, and the prescribing behaviour of physicians. Under the imposed vaccination policy and antiviral treatment in society, complex factors (costs and expected effects of the vaccines and treatments, and fear of being infected) trigger an emulous situation in which individuals avoid infection by the pre-emptive or ex post provision. Aside from the established voluntary vaccination game, we propose a treatment game model associated with the resistance evolution of antiviral/antibiotic overuse. Moreover, the imperfectness of vaccinations has inevitably led to anti-vaccine behaviour, necessitating a proactive treatment policy. However, under the excessively heavy implementation of treatments such as antiviral medicine, resistant strains emerge. The model explicitly exhibits a dual social dilemma situation, in which the treatment behaviour changes on a local time scale, and the vaccination uptake later evolves on a global time scale. The impact of resistance evolution and the coexistence of dual dilemmas are investigated by the control reproduction number and the social efficiency deficit, respectively. Our investigation might elucidate the substantial impacts of both vaccination and treatment in the framework of epidemic dynamics, and hence suggest the appropriate use of antiviral treatment.

DOI： 10.1098/rspa.2019.0484

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pre-emptive vaccination is regarded as one of the most protective measures to control influenza outbreak. There are mainly two types of influenza viruses-influenza A and B with several subtypes-that are commonly found to circulate among humans. The traditional trivalent (TIV) flu vaccine targets two strains of influenza A and one strain of influenza B. The quadrivalent (QIV) vaccine targets one extra B virus strain that ensures better protection against influenza; however, the use of QIV vaccine can be costly, hence impose an extra financial burden to society. This scenario might create a dilemma in choosing vaccine types at the individual level. This article endeavours to explain such a dilemma through the framework of a vaccination game, where individuals can opt for one of the three options: choose either of QIV or TIV vaccine or none. Our approach presumes a mean-field framework of a vaccination game in an infinite and well-mixed population, entangling the disease spreading process of influenza with the coevolution of two types of vaccination decision-making processes taking place before an epidemic season. We conduct a series of numerical simulations as an attempt to illustrate different scenarios. The framework has been validated by the so-called multi-agent simulation (MAS) approach.

DOI： 10.1098/rspa.2019.0608

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Social dilemmas are situations wherein individuals choose between selfish interest and common good. One example of this is the vaccination dilemma, in which an individual who vaccinates at a cost protects not only himself but also others by helping maintain a common good called herd immunity. There is, however, a strong incentive to forgo vaccination, thus avoiding the associated cost, all the while enjoying the protection of herd immunity. To analyze behavioral incentives in a vaccination-dilemma setting in which an optional treatment is available to infected individuals, we combined epidemiological and game-theoretic methodologies by coupling a disease-spreading model with treatment and an evolutionary decision-making model. Extensive numerical simulations show that vaccine characteristics are more important in controlling the treatment adoption than the cost of treatment itself. The main effect of the latter is that expensive treatment incentivizes vaccination, which somewhat surprisingly comes at a little cost to society. More surprising is that the margin for a true synergy between vaccine and treatment in reducing the final epidemic size is very small. We furthermore find that society-centered decision making helps protect herd immunity relative to individual-centered decision making, but the latter may be better in establishing a novel vaccine. These results point to useful policy recommendations as well as to intriguing future research directions.

DOI： 10.1103/PhysRevE.100.062402

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.5109/2547344

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Social dilemmas are situations wherein individuals choose between selfish interest and common good. One example of this is the vaccination dilemma, in which an individual who vaccinates at a cost protects not only himself but also others by helping maintain a common good called herd immunity. There is, however, a strong incentive to forgo vaccination, thus avoiding the associated cost, all the while enjoying the protection of herd immunity. To analyze behavioral incentives in a vaccination-dilemma setting in which an optional treatment is available to infected individuals, we combined epidemiological and game-theoretic methodologies by coupling a disease-spreading model with treatment and an evolutionary decision-making model. Extensive numerical simulations show that vaccine characteristics are more important in controlling the treatment adoption than the cost of treatment itself. The main effect of the latter is that expensive treatment incentivizes vaccination, which somewhat surprisingly comes at a little cost to society. More surprising is that the margin for a true synergy between vaccine and treatment in reducing the final epidemic size is very small. We furthermore find that society-centered decision making helps protect herd immunity relative to individual-centered decision making, but the latter may be better in establishing a novel vaccine. These results point to useful policy recommendations as well as to intriguing future research directions.

DOI： 10.1103/PhysRevE.100.062402

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The dynamics of a spreadable disease are largely governed by four factors: proactive vaccination, retroactive treatment, individual decisions, and the prescribing behaviour of physicians. Under the imposed vaccination policy and antiviral treatment in society, complex factors (costs and expected effects of the vaccines and treatments, and fear of being infected) trigger an emulous situation in which individuals avoid infection by the pre-emptive or ex post provision. Aside from the established voluntary vaccination game, we propose a treatment game model associated with the resistance evolution of antiviral/antibiotic overuse. Moreover, the imperfectness of vaccinations has inevitably led to anti-vaccine behaviour, necessitating a proactive treatment policy. However, under the excessively heavy implementation of treatments such as antiviral medicine, resistant strains emerge. The model explicitly exhibits a dual social dilemma situation, in which the treatment behaviour changes on a local time scale, and the vaccination uptake later evolves on a global time scale. The impact of resistance evolution and the coexistence of dual dilemmas are investigated by the control reproduction number and the social efficiency deficit, respectively.

DOI： 10.1098/rspa.2019.0484

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pre-emptive vaccination is regarded as one of the most protective measures to control influenza outbreak. There are mainly two types of influenza viruses-influenza A and B with several subtypes-that are commonly found to circulate among humans. The traditional trivalent (TIV) flu vaccine targets two strains of influenza A and one strain of influenza B. The quadrivalent (QIV) vaccine targets one extra B virus strain that ensures better protection against influenza; however, the use of QIV vaccine can be costly, hence impose an extra financial burden to society. This scenario might create a dilemma in choosing vaccine types at the individual level. This article endeavours to explain such a dilemma through the framework of a vaccination game, where individuals can opt for one of the three options: choose either of QIV or TIV vaccine or none. Our approach presumes a mean-field framework of a vaccination game in an infinite and well-mixed population, entangling the disease spreading process of influenza with the coevolution of two types of vaccination decision-making processes taking place before an epidemic season. We conduct a series of numerical simulations as an attempt to illustrate different scenarios. The framework has been validated by the so-called multi-agent simulation (MAS) approach.

DOI： 10.1098/rspa.2019.0608

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.5109/2547344

リポジトリ公開URL： http://hdl.handle.net/2324/4055213

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In a 2 x 2 prisoner's dilemma (PD) game, network reciprocity is one of the mechanisms for increasing social viscosity, which leads to a cooperative equilibrium. The Pairwise Fermi (PW-Fermi) rule has been accepted as an updating protocol, as its stochasticity is similar to the real-world human decision-making process. In this paper, we elucidated a modification to the PW-Fermi rule by utilizing the averaged payoff difference instead of the simple payoff difference between a focal agent and their neighbors. This led to a significantly enhanced level of network reciprocity. The mechanism of this enhancement is clarified by discussing the concepts of the enduring period (END) and the expanding period (EXP). (C) 2019 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.amc.2019.05.034

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In a 2 × 2 prisoner's dilemma (PD) game, network reciprocity is one of the mechanisms for increasing social viscosity, which leads to a cooperative equilibrium. The Pairwise Fermi (PW-Fermi) rule has been accepted as an updating protocol, as its stochasticity is similar to the real-world human decision-making process. In this paper, we elucidated a modification to the PW-Fermi rule by utilizing the averaged payoff difference instead of the simple payoff difference between a focal agent and their neighbors. This led to a significantly enhanced level of network reciprocity. The mechanism of this enhancement is clarified by discussing the concepts of the enduring period (END) and the expanding period (EXP).

DOI： 10.1016/j.amc.2019.05.034

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The promptness with which individuals respond to information has an important effect on the spread of epidemics. To study this effect, we establish a two-layer SIR/V epidemic model that incorporates the effects of information buzz and information costs in the framework of a vaccination game. Previous studies on this issue have generally assumed that only unaware people can become aware, and the relative vaccination cost is used to update their strategies for avoiding infection. Firstly, we introduce the idea that aware people can also become unaware because of a wicked rumor about a beneficial practice. Secondly, the relative cost of information is modeled for individual update strategies in a novel way of framing a game by introducing a two-strategy and 2 (information state A/UA) by 2(healthy/infected) state game, referred to as a two-under-two game. In this framework, susceptible, infected, and vaccinated individuals are divided into two states as unaware and aware, and recovered individuals are assumed to be aware, for an unbounded and well-mixed population. Information about wearing masks or taking other protection against diseases spreads locally for a season, and this information has a significant tendency to reduce the extent of contagious disease that persists through each generation of the model. Mathematical analysis shows that funds spent on awareness can reduce the vaccination cost and improve the epidemic threshold under certain conditions. (C) 2019 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cnsns.2019.04.007

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.5109/2349293

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The promptness with which individuals respond to information has an important effect on the spread of epidemics. To study this effect, we establish a two-layer SIR/V epidemic model that incorporates the effects of information buzz and information costs in the framework of a vaccination game. Previous studies on this issue have generally assumed that only unaware people can become aware, and the relative vaccination cost is used to update their strategies for avoiding infection. Firstly, we introduce the idea that aware people can also become unaware because of a wicked rumor about a beneficial practice. Secondly, the relative cost of information is modeled for individual update strategies in a novel way of framing a game by introducing a two-strategy and 2 (information state A/UA) by 2(healthy/infected) state game, referred to as a two-under-two game. In this framework, susceptible, infected, and vaccinated individuals are divided into two states as unaware and aware, and recovered individuals are assumed to be aware, for an unbounded and well-mixed population. Information about wearing masks or taking other protection against diseases spreads locally for a season, and this information has a significant tendency to reduce the extent of contagious disease that persists through each generation of the model. Mathematical analysis shows that funds spent on awareness can reduce the vaccination cost and improve the epidemic threshold under certain conditions.

DOI： 10.1016/j.cnsns.2019.04.007

記述言語：英語   掲載種別：研究論文（学術雑誌）  

リポジトリ公開URL： http://hdl.handle.net/2324/4055213

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pre-emptive vaccination policy used in controlling the rapid spreading of infectious diseases is considered as one of the most challenging issues imposed to mankind, causing enormous death tolls over the years. This paper dedicatedly studies the dilemma effect coming from the failure of getting perfect immunity to those individuals who committed vaccination earlier. Therefore, we propose a new theoretical model that slows down the infection spreading and also facilitates quicker recovery time than what the previous model does even if a vaccinator fails to obtain perfect immunity. We name this effect as the "positive secondary effect" of vaccination as it gives a second chance to the vaccinators which in return subdues the rapid spreading that helps in producing better social average payoff as well as keeping the final epidemic size smaller. Moreover, to address the positive secondary effect more precisely, we introduce two different parameters; namely, relaxation parameter (eta) and foster parameter (delta) in two different directions to quantify the individual effects resulting from each of the parameter space as well as their superposition effect. An in-depth discussion focuses on the influential role played by our proposed model via discounting and faster recovery effects while a second chance is given to the vaccinators. In addition, we also examine the situation when discounting effect brought by eta outperforms very much than its faster recovery controlled by delta as well as the superposition effects. Unlike all previous studies dealing with vaccination game, we pay much attention to investigating the secondary effect of imperfect vaccination policy. Our proposed theoretical scheme completely reproduces the decision-making process of choosing an imperfect provision based on evolutionary game theory entailed with the widely used SIR (Susceptible-Infected-Recovered) epidemic model. Without considering any spatial structure and perfect vaccination policy, our model presumes the population being infinite and well-mixed to represent the infection spreading dynamics mathematically. This study is conducted throughout using the so-called theoretical approach. Besides that, three different updating rules based on evolutionary game theory have also been considered to investigate all possible situations. Later on, we draw 2D full phase diagrams showing the final epidemic size, vaccination coverage, and average social payoff quantitatively. Finally, our theoretical result is compared with the counterpart result obtained from the multi-agent simulation (MAS) approach and a good agreement is found, hence the appropriateness of the proposed model is fully justified. (C) 2019 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chaos.2019.05.031

記述言語：その他   掲載種別：研究論文（その他学術会議資料等）  

© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 Evaluation of the aggregated air-conditioning load of multiple dwellings is important for demand response through the optimum control of numerous air-conditioners (A/Cs), for development of smart-city or smart-community technologies. However, past studies have mainly focused on the characteristics of A/C load in a single household. With this background, the authors conducted statistical analysis of time-series data for A/C electricity consumption in 489 dwellings in Osaka, Japan, and 20 dwellings in Kuala Lumpur, Malaysia to grasp the feature of aggregated A/C load of multiple dwellings. The findings of this analysis are followings: 1) the aggregated A/C load peak per dwelling decreased by almost 50&#37; as the number of dwellings increased from 1 to 10, due to the offset of the diverse time-patterns of A/C load. 2) The occurrence of the top 2.5&#37; A/C load shows strong time and date dependency for an A/C load aggregated by many dwellings.

DOI： 10.1051/e3sconf/201911104057

記述言語：その他   掲載種別：研究論文（学術雑誌）  

© 2019 Elsevier Ltd Most studies on indoor ventilation have utilized wind-tunnel experiments (WTEs) or computational fluid dynamics based approaches under well-controlled flow conditions. However, the effects of urban boundary layer flow with variable wind directions and various turbulence scales on the ventilation driven by the pressure differences between the upwind and downwind sides of a building within a block array is still under discussion. Therefore, we conducted outdoor experiments at comprehensive outdoor scale model (COSMO) experiment sites in an urban climate to clarify the relationships between the building wall pressure differences and the approaching flow. The pressure coefficients for the outdoor site were comparable with those obtained during previous WTEs. Accordingly, temporal variations in the wind speed and pressure coefficient on the target block were investigated in detail using low-pass filtering operations. The relationships between the filtered wind speed and the pressure differences indicate that the slower temporal variations in the wall pressure showed good agreement with the filtered approaching flow. In addition, the correlation coefficient between the filtered wind speed and the wall pressure differences quantified the apparent coherence between the turbulent flow and the ventilation rate. Furthermore, the statistics of the ventilation rate were determined based on the conventional model to clarify the effects of the turbulent flow on the natural ventilation rate. The ratios between the mean and short-term ventilation rates imply that the short-term ventilation rate presented dramatic temporal fluctuations owing to the various scale turbulence generated by the atmospheric flow.

DOI： 10.1016/j.buildenv.2019.106170

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Pre-emptive vaccination policy used in controlling the rapid spreading of infectious diseases is considered as one of the most challenging issues imposed to mankind, causing enormous death tolls over the years. This paper dedicatedly studies the dilemma effect coming from the failure of getting perfect immunity to those individuals who committed vaccination earlier. Therefore, we propose a new theoretical model that slows down the infection spreading and also facilitates quicker recovery time than what the previous model does even if a vaccinator fails to obtain perfect immunity. We name this effect as the “positive secondary effect” of vaccination as it gives a second chance to the vaccinators which in return subdues the rapid spreading that helps in producing better social average payoff as well as keeping the final epidemic size smaller. Moreover, to address the positive secondary effect more precisely, we introduce two different parameters; namely, relaxation parameter (η) and foster parameter (δ) in two different directions to quantify the individual effects resulting from each of the parameter space as well as their superposition effect. An in-depth discussion focuses on the influential role played by our proposed model via discounting and faster recovery effects while a second chance is given to the vaccinators. In addition, we also examine the situation when discounting effect brought by η outperforms very much than its faster recovery controlled by δ as well as the superposition effects. Unlike all previous studies dealing with vaccination game, we pay much attention to investigating the secondary effect of imperfect vaccination policy. Our proposed theoretical scheme completely reproduces the decision-making process of choosing an imperfect provision based on evolutionary game theory entailed with the widely used SIR (Susceptible–Infected–Recovered) epidemic model. Without considering any spatial structure and perfect vaccination policy, our model presumes the population being infinite and well-mixed to represent the infection spreading dynamics mathematically. This study is conducted throughout using the so-called theoretical approach. Besides that, three different updating rules based on evolutionary game theory have also been considered to investigate all possible situations. Later on, we draw 2D full phase diagrams showing the final epidemic size, vaccination coverage, and average social payoff quantitatively. Finally, our theoretical result is compared with the counterpart result obtained from the multi-agent simulation (MAS) approach and a good agreement is found, hence the appropriateness of the proposed model is fully justified.

DOI： 10.1016/j.chaos.2019.05.031

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Evaluation of the aggregated air-conditioning load of multiple dwellings is important for demand response through the optimum control of numerous air-conditioners (A/Cs), for development of smart-city or smart-community technologies. However, past studies have mainly focused on the characteristics of A/C load in a single household. With this background, the authors conducted statistical analysis of time-series data for A/C electricity consumption in 489 dwellings in Osaka, Japan, and 20 dwellings in Kuala Lumpur, Malaysia to grasp the feature of aggregated A/C load of multiple dwellings. The findings of this analysis are followings: 1) the aggregated A/C load peak per dwelling decreased by almost 50% as the number of dwellings increased from 1 to 10, due to the offset of the diverse time-patterns of A/C load. 2) The occurrence of the top 2.5% A/C load shows strong time and date dependency for an A/C load aggregated by many dwellings.

DOI： 10.1051/e3sconf/201911104057

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Most studies on indoor ventilation have utilized wind-tunnel experiments (WTEs) or computational fluid dynamics based approaches under well-controlled flow conditions. However, the effects of urban boundary layer flow with variable wind directions and various turbulence scales on the ventilation driven by the pressure differences between the upwind and downwind sides of a building within a block array is still under discussion. Therefore, we conducted outdoor experiments at comprehensive outdoor scale model (COSMO) experiment sites in an urban climate to clarify the relationships between the building wall pressure differences and the approaching flow. The pressure coefficients for the outdoor site were comparable with those obtained during previous WTEs. Accordingly, temporal variations in the wind speed and pressure coefficient on the target block were investigated in detail using low-pass filtering operations. The relationships between the filtered wind speed and the pressure differences indicate that the slower temporal variations in the wall pressure showed good agreement with the filtered approaching flow. In addition, the correlation coefficient between the filtered wind speed and the wall pressure differences quantified the apparent coherence between the turbulent flow and the ventilation rate. Furthermore, the statistics of the ventilation rate were determined based on the conventional model to clarify the effects of the turbulent flow on the natural ventilation rate. The ratios between the mean and short-term ventilation rates imply that the short-term ventilation rate presented dramatic temporal fluctuations owing to the various scale turbulence generated by the atmospheric flow.

DOI： 10.1016/j.buildenv.2019.106170