Griffin, ChristopherSemonsen, JustinBelmonte, Andrew
19页查看更多>>摘要：We study the network replicator equation and characterize its fixed points on arbitrary graph structures for 2 x 2 symmetric games. We show a relationship between the asymptotic behavior of the network replicator and the existence of an independent vertex set in the graph and also show that complex behavior cannot emerge in 2 x 2 games. This links a property of the dynamical system with a combinatorial graph property. We contrast this by showing that ordinary rock-paper-scissors (RPS) exhibits chaos on the 3-cycle and that on general graphs with >= 3 vertices the network replicator with RPS is a generalized Hamiltonian system. This stands in stark contrast to the established fact that RPS does not exhibit chaos in the standard replicator dynamics or the bimatrix replicator dynamics, which is equivalent to the network replicator on a graph with one edge and two vertices (K2).
原文链接:
NSTL
Elsevier
Chen, ZhengLiu, JieyuLi, LiWu, Yongping...
12页查看更多>>摘要：Climate change has resulted in instability of semi-arid ecosystems under global warming, especially during the last decades. Hulun Buir Grassland is suffering from prominent warming and drying. Therefore, it is vital to research the change of climate factors such as precipitation, temperature and carbon dioxide concentrations [CO2] on vegetation dynamics. A vegetation-climate dynamic model is applied in a typical semi-arid area of Hulun Buir Grassland in China to research the effects on vegetation distribution due to climate change. Various climate scenarios with representative concentration pathways (Current, RCP2.6, RCP4.5, RCP8.5) are compared. Temperature, precipitation and CO2 fertilization effects play critical roles on vegetation growth. The vegetation pattern shows the synergies of temperature, precipitation and [CO2]. From our research, the vegetation pattern here may change from dense spot state to bare state. The ecosystem shows the fastest degradation under Current scenario, suggesting that Current scenario is the worst climate condition for vegetation growth there. However, the RCP2.6 scenario is an ideal climate state for vegetation growth in which the radiative forcing is low, precipitation increases slightly, and vegetation can grow well. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Enayat, TahaArdebili, Mohsen MehraniKivi, Ramtin ReyhaniAmjadi, Bahador...
15页查看更多>>摘要：How does society work? How do groups emerge within society? What are the effects of emotions and memory on our everyday actions? George Homans, like us, had a perspective on what society is, except that he was a sociologist. Homans theory, which is an exchange theory, is based on a few propositions about the fundamental actions of individuals, and how values, memory, and expectations affect their behavior. In this paper, as Homans predicted, our main interest and purpose are to find out whether these propositions lead to the emergence of groups. To do so, computationally, Based on Homans' prepositions, we provide the opportunity for each agent to exchange with other agents. That is, each agent transacts with familiar agents based on his previous history with them and transacts with newly found agents through exploration. The importance of our work is that we have scrutinized the consequences of an actual sociological theory through the eyes of simulation. At the end of our investigation, we discuss other possible directions for further research. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Li, Ming-GenFan, Li-MingBao, Jing-Dong
9页查看更多>>摘要：Particle motion often exhibits anomalous diffusion arising from spatial inhomogeneity in the complex structures of soft materials. Spatial inhomogeneity induces a power-law frictional landscape for the mean-squared displacement of particles in a force-free environment; expressly, < x(2)(t)> similar to t(alpha) (i.e., 0 < alpha <= 2). We calculate analytically and numerically this mean-squared displacement. By comparing with a XY system in a logarithmic potential, for which anomalous diffusion transitions occur in regimes from normal diffusion to confinement, we investigated the diffusive dynamics of a realistic system away from its equilibrium state. Spatial nonlocal processes were found to be equivalent to time nonlocal ones (i.e., non-Ohmic memory); specifically, the weaker the effective friction produced, the stronger is the diffusion induced. This overcomes the difficulty encountered when evaluating memory effects in experiments. Aided by the generalized Green-Kubo formula, our model is also compared with diffusion processes obeying the scaling behavior of the velocity correlation function. The present study on anomalous diffusion in inhomogeneous environments is helpful because the phenomenon appears in soft, solid and biological matter. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Abidemi, AfeezOwolabi, Kolade M.Pindza, Edson
22页查看更多>>摘要：In this paper, a seven-dimensional nonlinear mathematical model featuring the vertical transmission in humans, saturated incidence functions, and human population with good and poor community hygiene is formulated to describe the dynamics of Lassa fever (LF) disease transmission between the interacting human and rodent populations. The model is analysed to investigate the dynamical behaviour of its solutions using some theories of dynamical system of ordinary differential equations. The basic reproduction number, R-0, of the model is established. A suitable Lyapunov function is constructed to establish the global asymptotic behaviour of the model about the Lassa fever-free equilibrium. Sensitivity analysis is carried out to gain insightful information about how R-0 is influenced by the variation in the model parameters. Numerical simulations are conducted to examine the effects of the most sensitive model parameters on the population dynamics of LF. The results obtained provide epidemiological insights into the impact of key model parameters on the transmission dynamics of LF and suggest some measures to fight or guide against the disease spread in a population. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Chehardoli, HosseinGhasemi, Ali
12页查看更多>>摘要：The adaptive robust size-independent consensus problem of leader following multi-agent systems (MASs) with unknown dynamics based on only onboard relative dis-placement information is studied. It is assumed that all followers only can measure the relative displacement regarding their adjacent agents. Due to lack of communication tools, each follower must estimate its uncertain dynamics and the leader acceleration simultaneously. A decentralized adaptive robust consensus law is presented to achieve the global state consensus for uncertain second-order multi-agent systems by employing only relative displacement information. According to the Lyapunov theorem, it is proved that without any knowledge about the number of followers and communication graph, the global state consensus is attained. The control and adaptive gains are tuned independently of the number of followers and communication topology. Therefore, the controller is robust against size-changing and can be applied to large-scale uncertain MASs. Afterward, it is verified that if the basis vectors are persistently exciting (PE), the estimation errors of uncertain vectors tend to zero. Several numerical scenarios are prepared to confirm the efficiency of this method. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Gabrick, Enrique C.Protachevicz, Paulo R.Batista, Antonio M.Iarosz, Kelly C....
12页查看更多>>摘要：In this work, to support decision making of immunisation strategies, we propose the inclusion of two vaccination doses in the SEIR model considering a stochastic cellular automaton. We analyse three different scenarios of vaccination: (i) unlimited doses, (ii) limited doses into susceptible individuals, and (iii) limited doses randomly distributed overall individuals. Our results suggest that the number of vaccinations and time to start the vaccination is more relevant than the vaccine efficacy, delay between the first and second doses, and delay between vaccinated groups. The scenario (i) shows that the solution can converge early to a disease-free equilibrium for a fraction of individuals vaccinated with the first dose. In the scenario (ii), few two vaccination doses divided into a small number of applications reduce the number of infected people more than into many applications. In addition, there is a low waste of doses for the first application and an increase of the waste in the second dose. The scenario (iii) presents an increase in the waste of doses from the first to second applications more than the scenario (ii). In the scenario (iii), the total of wasted doses increases linearly with the number of applications. Furthermore, the number of effective doses in the application of consecutive groups decays exponentially overtime. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Ding, L. J.Xiang, L.Zhong, Y.
10页查看更多>>摘要：We study the quantum phase transitions (QPTs) and quantum criticality of transverse field Ising model with off-diagonal exchange interactions. In the absence of magnetic field, the clockwise spiral (CWS), counterclockwise spiral (CCWS) and longitudinal ferromagnetic (xFM) phases are revealed by the spin chirality vector lcz and longitudinal spin-spin correlation C-xx mutually. The general QPT is diagnosed by the temperature power-law divergence of Gruneisen ratio (GR) F ~ +/- T-1. The critical scaling is further done to capture the quantum critical point (QCP) by analyzing lcz and specific heat, which offers a direct access to distill the critical exponents (delta, beta, alpha) that fulfill the Essam-Fisher relation alpha + beta(1 + delta)=2, providing a new clue to detect the general QPT. Subsequently, some scaling hypothesis equations are proposed to check the scaling analysis. In a magnetic field, an additional field-induced transverse ferromagnetic (zFM) phase is unveiled. Specifically, for the xFM phase transition into zFM one, the transverse field Ising terms predominates, which approximately keeps the Z(2) symmetry at h(c) = 1, giving rise to the self-dual quantum criticality, demonstrated by the constant of GR irrelevant of temperature. Furthermore, the gapped and gapless low-lying excitations of quantum phases are manifested by the thermal Drude weight and specific heat. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
