查看更多>>摘要：We investigate the ability-based fitness calculation in an asymmetric setup to the evolution of cooperation on square lattice. In particular, if players can maintain its strategy for a round, then its abilities will increase 1, otherwise, its ability will turn to 0. We also assume that if players' abilities exceed a certain threshold M, then its environment is integrated into its fitness calculation via a simple parameter alpha. Through extensive numerical simulation, we find that large threshold M decreases cooperation, and large alpha, players' fitness is mainly decided by its dynamical environment, promotes cooperation. We also provide theoretical analysis and get the same results with simulation. Finally, we test its robustness on homogeneous random network and small-world network. Our work provides a deeper insight to network reciprocity. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Explaining the evolution of cooperation represents one of the greatest challenges in both evolutionary biology and social science. However, asymmetrical interaction, as one typical characteristic of cooperative system, has not been sufficiently considered in the existing literature for the evolution of cooperation. Incorporating the asymmetry in the strategy sets, we here construct an asymmetric game model with the so-called carrot-stick strategy, which is a mixed strategy of reward and punishment. Based on mathematical analyses, it is unveiled that this asymmetric interaction can lower the dilemma of cooperation: the dominant players and recipient players might coexist through cycle frequency. Further analysis shows that the multi-equilibria are possible, which depend on the payoff parameters and the initial conditions. That is to say, by setting up different values of the cost-to-benefit, the punishment-to-benefit, and the reward-to-benefit, we can recover three basic evolutionary dynamics of systems: dominance; bistability and coexistence. These theoretical observations are consistent with existing empirical outcomes that asymmetric sanction or reward of host species might solve the conflicts between the actors in the fig-fig wasp mutualism or in the cleaner fish-client mutualism. It is thus suggested that this asymmetric strategy setup may shed new light into the solution of social dilemmas. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：This paper investigates the problem of robust control and fault detection for discrete-time switched systems. The main goals are to design controller/fault detectors and a switching rule to guarantee the control and detection objectives simultaneously. The switching rule is constructed based on persistent dwell time (PDT) with an average dwell time (ADT) constraint. The introduced ADT constraint can allow a much smaller PDT lower bound to be designed, which provides more freedom of designing switching signal. Next, some time-varying dynamic output feedback controllers/detectors matching different switching processes of PDT are constructed such that the closed-loop systems meet the desired objectives. The corresponding robust control and fault detection levels can be characterized by a class of non-weighted performance indexes. Finally, the effectiveness of the proposed results is illustrated by an example. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：This article is devoted to the non-fragile asynchronous state estimation problem for Markovian switching complex-valued networks subject to randomly occurring nonlinearities (RONs) and external stochastic disturbances. Two mutually uncorrelated random variables with known statistical properties are introduced to depict the existing RONs. Considering the case that the information concerning to the system modes cannot be completely acquired by the state estimator to be designed, the asynchronous phenomenon is considered via a hidden Markov model with only partial mode detection probabilities being accessible. By resorting to the intensive stochastic analysis as well as an improved complex-valued reciprocal convex inequality, some mode-dependent criteria are provided which ascertain that the estimation error system is asymptotically mean square stable. In addition, the estimator gains desired can be appropriately designed by resorting to feasible solutions of a set of complex matrix inequalities. One numerical example is also provided to demonstrate effectiveness of the estimation scheme proposed. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：This paper investigates the finite-time annular domain stability and stabilization of stochastic systems, described by an Ito-type differential equation, in which the systems are driven by both Wiener noises and Poisson jumps. First, a new inequality called reverse differential Gronwall inequality is established to achieve less conservative conditions for finite-time annular domain stability. Second, some sufficient conditions are derived to guarantee that the closed-loop system is finite-time annular domain stable by constructing a state feedback controller and an observer-based controller, respectively. All related conditions can be expressed in terms of matrix inequalities and corresponding algorithms are given. Finally, two numerical examples are presented to verify the validity of the derived results, and the effect of Poisson jump intensity on the boundary of the system states is illustrated. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：This article provides the first analysis of the differentially private computation of three centrality measures, namely eigenvector, Laplacian and closeness centralities, on arbitrary weighted graphs, using the smooth sensitivity approach. We do so by finding lower bounds on the amounts of noise that a randomised algorithm needs to add in order to make the output of each measure differentially private. Our results indicate that these computations are either infeasible, in the sense that there are large families of graphs for which smooth sensitivity is unbounded; or impractical, in the sense that even for the cases where smooth sensitivity is bounded, the required amounts of noise result in unacceptably large utility losses. (C) 2021 The Authors. Published by Elsevier Inc.
查看更多>>摘要：We develop a linearized compact alternating direction implicit (ADI) numerical method to solve the nonlinear delayed Schrodinger equation in two-dimensional space. By discrete energy estimate method, we analyse the convergence of the fully-discrete numerical method, and show that the numerical scheme is of order O(Delta t(2) + h(4)) with time stepsize Delta t and space stepsize h. At last, we present several numerical examples to confirm theoretical analyses. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：The objective of this paper is to analyze the efficiency of a spatial moments model (SMM) in approximating an individual-based model (IBM) dedicated to the study of the aggregation phenomenon in a phytoplankton population. The dynamic system of spatial moments consists of a system of integro-differential equations derived from a phytoplankton IBM. The later is built on the basis of stochastic processes describing the dynamics of phytoplankton cells and their interactions. These processes are: (1) the movement of cells, which takes into account the random dispersion of cells in water and the attraction between cells due to their chemosensory abilities, (2) the demographical process (cell division or cell death) in which, the effect of local competition for nutrient resources on the cell's division process is taken into account through the use of density dependent division rate. We solve numerically the SMM and then simulate the two models (IBM and SMM), for a set of scenarios chosen to analyze the aggregation and the different interactions in the population. The numerical results have led to the conclusion that in contrast to the mean-field model (MFM), the method of spatial moments is efficient to capture the dynamics of the IBM. Further, the SMM easily permits the prediction of long term behavior of phytoplankton cells and their spatial structure, namely that the aggregation behavior of the cells is very much related to their cellular diffusion and the perceptual radius. Concerning competition on resources, this process has a short and medium-term effect on aggregation, since regardless of its intensity, in the long term the population tends to be stable with formation of aggregates, as a result of the equilibrium between different mechanisms, including reproduction, competition, diffusion and cells attractions due to chemosensory abilities. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：In industrial control systems, industrial infrastructure is often attacked by hackers. Due to the serious sample imbalance in industrial control data, the traditional machine learning method has poor performance in anomaly detection. In this paper, TrAdaboost algorithm is applied to industrial control anomaly detection. The samples that are easy to classify are taken as the source domain data, and the samples with poor classification effect are taken as the target domain. The source domain data is used to guide the target domain data training. Then, we improve the traditional TrAdaboost algorithm from two aspects of initial weight and final classifier, and apply it to industrial control anomaly detection. Finally, the performance of the algorithm on two different industrial control data sets is verified. And the improved algorithm is compared with other traditional algorithms. The experimental results show that the improved TrAdaboost algorithm has a significant advantage in predicting categories with a small sample size. This algorithm can accurately identify a few abnormal samples. Moreover, the F1 value, recall and precision value of the improved TrAdaboost algorithm on the two data sets have been significantly improved. This indicates that the improved TrAdaboost algorithm greatly improves the overall prediction accuracy of the model. (C) 2021 Published by Elsevier Inc.
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