查看更多>>摘要：A number of empirical studies have proved that human decision-making behaviors are bounded rational with external regulations and intrinsic motivations. In some situations, without information exchanges, an individual could make decisions only based on its own payoff, experience, memory and aspiration level. Such process can be theoretically expressed as the aspiration-driven dynamics applied in anonymous evolutionary games. On the other hand, from the perspective of behavioral economics and cognitive psychology, Prospect Theory qualitatively describes the bounded rationality of human decision-making behaviors under uncertain conditions. Here we explore a new approach to quantitatively construction of such bounded rationality by combining the aspiration updating rules in evolutionary games with the asymmetric utility value function in Prospect Theory. Monte Carlo simulations are carried out on a square lattice using the model of public goods game. The simulation results have shown that the level of cooperation at equilibrium states depends on the combined effects of synergy factor, individual greediness and sensitivity to gains and losses. Besides, the results give a reasonable explanation for the spontaneous emergence of cooperation among irrelevant individuals as well as the necessary conditions for the full-cooperation state. Furthermore, we argue that the study on human decisionmaking behaviors in groups requires more extensive and profound interdisciplinary researches. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：In this paper, the asynchronous control problem is addressed for semi-Markov switching systems with a memory-based event-triggered mechanism. In light of the asynchronous phenomenon between the resulting dynamic modes and the memory controller modes, a more general hidden semi-Markov model is expected. Notably, aiming at decrease the triggering intervals while improving the dynamic performance, a novel mode-dependent memory-based event-triggered mechanism is proposed, whose triggering condition varies with some historic released data. By virtue of the hidden semi-Markov model and historic released data, a memory asynchronous control strategy is skillfully synthesized. By resorting to Lyapunov theory, some criteria are formulated to guarantee the stochastically stable of the resulting dynamic. Eventually, the feasibility of the presented approach is verified by a practical example. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：It is well-known that the number of spanning trees, denoted by tau(G), in a connected multi-graph G can be calculated by the Matrix-Tree Theorem and Tutte's deletioncontraction formula. In this short note, we find an alternate method to compute tau(G) by degrees of vertices. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：This paper presents a distributed formation tracking control strategy which acts on multiple quadrotor unmanned aerial vehicles (QUAVs) formation control under external disturbance and asymmetric output error constraints. An asymmetric barrier Lyapunov function (BLF) is applied to ensure the constraint of output error. Based on graph theory and backstepping control method, a distributed formation controller is designed to achieve the formation and maintenance of formations, where external disturbance is handled by disturbance observer (DO). In the framework of Lyapunov theory, the bounded stability of the closed-loop system is proved, and the output error is remained within the constraint range. The superiority and effectiveness of the designed control strategy is verified by the compared simulation. (C) 2021 Published by Elsevier Inc.
查看更多>>摘要：In this article, we study the stability and transition of couple stress fluid saturated porous media, heated from below and cooled from above by employing a thermal non-equilibrium model. Careful analysis shows that the thermal non-equilibrium model has a global attractor, and the global attractor only consists of the basic solution if the Rayleigh number is equal or below a threshold. In generic case where the transitioning eigenvalue has multiplicity one, we show that the transition involved is of continuous type, and the basic solution will be bifurcated to two stable convection solutions which attract globally. If the leading eigenvalue multiplicity is two, the transition is also continuous and a global attractor homeomorphic to the unit circle bifurcates. The attractor then contains four steady-state convection solutions, two of which are stable while the other two are unstable. Further numerical works give more details in the transition process including the bifurcated roll structure. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Mathematical models have been widely used for the study of water quality. Regarding the pollution of water resources by organic matter, dissolved oxygen (DO) and biochemical oxygen demand (BOD) are important indicators for their monitoring. In this way, this research presents a two-dimensional mathematical model in space that evolves over time, for the study of the variations in concentrations of these variables, through a coupled system of non-linear partial differential equations, with Holling type III reaction kinetics between DO and BOD. Under some simplifications, the stability of the equilibrium points of the model is analyzed. An approximate solution is proposed using the centered finite difference (CFD) method for spatial variables and the Crank-Nicolson method for the temporal variable. An upwind scheme was employed in the advective-term discretization. Computer simulations were performed using Matlab software, in a rectangular domain. For the advective transport, the influences of the wind and the current given by a parabolic profile were considered. We performed a series of space-time numerical simulations and found that the model allows the analysis of regions with higher and/or lower DO and BOD concentrations, as well as the temporal variations of concentrations at specific points in the domain, and the influence of diffusive-advective transport in the mass transfer process. (C) 2021 Elsevier Inc. All rights reserved.
Kaneba, Christopher MunyiwaMu, XiaowuLi, XinWu, Xihui...
12页
查看更多>>摘要：The paper investigates the event-triggered control problem for fault tolerant control system with actuator failure and randomly occurring parameter uncertainty. Firstly, the hybrid event-triggered control scheme is adopted for the fault tolerant control system subjected to actuator failure and randomly occurring parameter uncertainty in this paper, which could greatly decrease the amount of network data transmission and save communication resources. By utilizing the delay system method, the event-triggered fault tolerant control system is modeled as a delay system. Then, by constructing appropriate Lyapunov-Krasovskii functional, sufficient conditions are derived in form of linear matrix inequalities (LMIs) to guarantee the system is stochastically passive with prescribed passive performance gamma. The impact of the actuator fault and the random occurring parameter uncertainty are studied under the unified framework. Eventually, two simulation examples including F-404 aircraft engine system are presented to illustrate the effectiveness of the proposed theoretical findings. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：The formal equivalence between the Hopfield network (HN) and the Boltzmann Machine (BM) has been well established in the context of random, unstructured and unbiased patterns to be retrieved and recognised. Here we extend this equivalence to the case of "biased" patterns, that is patterns which display an unbalanced count of positive neurons/pixels: starting from previous results of the bias paradigm for the HN, we construct the BM's equivalent Hamiltonian introducing a constraint parameter for the bias correction. We show analytically and numerically that the parameters suggested by equivalence are fixed points under contrastive divergence evolution when exposed to a dataset of blurred examples of each pattern, also enjoying large basins of attraction when the model suffers of a noisy initialisation. These results are also shown to be robust against increasing storage of the models, and increasing bias in the reference patterns. This picture, together with analytical derivation of HN's phase diagram via self-consistency equations, allows us to enhance our mathematical control on BM's performance when approaching more realistic datasets. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：In this paper, the problem of robust fixed-time trajectory tracking control for a class of nonlinear Euler-Lagrange (EL) systems with exogenous disturbances and uncertain dynamics is addressed. A neural network (NN)-based adaptive estimation algorithm is employed to approximate the continuous uncertain dynamics, so that the dynamics of the EL system can be rebuild based on the estimations. In order to guarantee the EL system following the desired trajectory within a fixed-time, an adaptive fixed-time sliding mode control law is proposed to remedy the negative influence of uncertain dynamics and exogenous disturbances. Lyapunov stability theory is utilized to prove the stability and fixed-time convergence of the EL system. The efficiency of the developed NN-based adaptive fixed-time control strategy is substantiated with simulation results. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：In this paper, we develop an iterative scheme to construct multiscale basis functions within the framework of the Constraint Energy Minimizing Generalized Multiscale Finite Element Method (CEM-GMsFEM) for the mixed formulation. The iterative procedure starts with the construction of an energy minimizing snapshot space that can be used for approximating the solution of the model problem. A spectral decomposition is then performed on the snapshot space to form global multiscale space. Under this setting, each global multiscale basis function can be split into a non-decaying and a decaying parts. The non-decaying part of a global basis is localized and it is fixed during the iteration. Then, one can approximate the decaying part via a modified Richardson scheme with an appropriately defined preconditioner. Using this set of iterative-based multiscale basis functions, first-order convergence with respect to the coarse mesh size can be shown if sufficiently many times of iterations with regularization parameter being in an appropriate range are performed. Numerical results are presented to illustrate the effectiveness and efficiency of the proposed computational multiscale method. (C) 2021 Elsevier Inc. All rights reserved.
NSTL
Elsevier