查看更多>>摘要：In the framework of a Cournot oligopoly game with isoelastic demand, we examine the simultaneous presence of both market saturation and strategic delegation. Although these two (realistic) aspects have already been considered in the literature each on its own, we aim at deepening their joint interactions when matched together in oligopolistic competition. In addition, we admit the possibility that delegation activities actuated by firms to weaken or even exclude competitors from the market may cease if undertaken by successful players, which thus regain their pure profit maximizing behavior. In this context, a limited market saturation level (positively) influences the effectiveness of delegation strategies and, at the same time, can sustain equilibrium configurations for the winning (monopolistic) firm even under the isoelastic market structure. Through local stability analysis, we show how the combination of strategic delegation with market saturation contributes to determine the equilibrium number of active players and the local asymptotic stability of the (economically relevant) equilibrium. Moreover, non-equilibrium dynamics reveal the presence of periodic cycles along which a firm is active while its competitors alternatively exits and enters the market. We show why these interesting scenarios are due to the joint interplay between strategic delegation and market saturation.
Kofane, T. C.Tabi, C. B.Otsobo, J. A. AmbassaMegne, L. Tiam...
9页
查看更多>>摘要：We investigate the formation and propagation of gap-soliton bullets in nonlinear periodic waveguides at fre-quencies close to the gap for Bragg reflection beyond the paraxial approximation. Using a multiple-scales analy-sis, we derive a two-dimensional (2D) nonlinear Schrodinger equation with higher-order correction terms that consider the nonparaxial regimes in the slowly-varying envelope approximation. In addition, a fully numerical simulation of the newly derived model equation demonstrates that the mutual balancing between Kerr, dimen-sionality, higher-order dispersions and nonparaxiality allows shape-preserving propagation of gap-soliton bul -lets in a grating waveguide. (c) 2022 Published by Elsevier Ltd.
查看更多>>摘要：According to the BIOS theory, attention deficit hyperactivity disorder (ADHD) is a disorder that transfers the power of the high-frequency bands to the low-frequency bands by changing the electrical actions generated by the brain's opposite structures. Nevertheless, studies on this disorder have often focused on the EEG walks (voltage levels) and provided no information about the status of the brain's opposites, which generate the EEG actions (voltage changes in time). In this study, we accordingly investigated the status of partial opposites in the trigonometric plots obtained from the EEG signals of children with and without ADHD, which have been recorded under the resting eyes-open and eyes-closed conditions. In other words, we first extracted a set of features from the status of partial opposites activated in the trigonometric space and the status of transitions in this plot. Then, we evaluated these features to separate children with and without ADHD by using the t-test analysis and the SVM classifiers. Generally, the outcomes of this analysis in addition to improving the separability of the ADHD children with a figure of merit (FOM) of about 72.4% detected that ADHD changes the EEG actions, so that the larger EEG actions usually occur more than the smaller EEG actions. Therefore, it seems that the proposed technique can significantly improve clinical protocols, especially in applications such as diagnostic tools, neurofeedback, and game therapy. (c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Assessment of the dynamical complexity of signals or systems is very crucial in medical diagnostics, fault analysis of mechanical systems, astrophysics and many more. Although there have been tremendous improvements in entropy measures as complexity estimator, most of these measures are affected by short data length and are highly sensitive to predetermined parameters. These issues are addressed quite successfully by distribution entropy (DistEn), a robust estimator of complexity for many signals. However, it fails to discriminate random noise, pink noise and Henonmap-based chaotic signals. Furthermore, it underestimates the complexity of chaotic signals at higher scales. To circumvent these problems, we propose an improved distribution entropy (ImDistEn), which utilizes embedded vectors' orientation, ordinality and l(1)-norm distance information for its computation. Simulation results show that ImDistEn can provide clear distinction of different classes of real-world signals, besides accurately assessing the complexity of various synthetic signals. (C) 2022 Elsevier Ltd. All rights reserved.
Mehrabbeik, MahtabLevine, Alexandra T.Jafari, SajadMerrikhi, Yaser...
9页
查看更多>>摘要：Working memory serves as a basis for many cognitive functions, including attention, decision-making, and learning. When engaged, it is often associated with an increase in the average neural firing rates across different sensory and sensorimotor regions of the brain. However, a modulation of the neural firing rate in extrastriate cortex, involved in visual processing, has never been reported during the maintenance of visual information. Here, for the first time, we show that despite the absence of a modulation in the firing rate of the neurons in the middle temporal cortex (part of extrastriate cortex), their nonlinear dimensionality, captured by the Higuchi method, is increased when the locus of spatial working memory corresponds with the neurons' receptive field. Our finding sheds more light on the neural mechanisms of working memory and would help diagnosis processes of cognitive disorders that are thought to be rooted in a malfunctioning working memory. It also calls attention toward the need for novel approaches toward studying the neural activities beyond a modulation in the average discharge rate. (c) 2022 Elsevier Ltd.
查看更多>>摘要：Systems in nature are for the most part rich in connection, interaction, and communication in various ways that are generally complex. Synchronization is one of the main phenomenons associated with couple systems. Synchronization may be understood as a process where several systems adjust time scales of their oscillations or a given property of their motion over time due to their interactions. In compact designs, unconnected circuits may interact through the magnetic field. This interaction can be avoided or exploited in some cases. This work investigated the dynamics and the synchronization study of a set of magnetically coupled van der Pol oscillators coupled to a linear circuit (the VDPCL oscillator) in wireless interaction. The coupling coefficient between the coupled but unconnected oscillators is used as the only control parameter allowing investigating the dynamics and the synchronization of the oscillators. We first derive a mathematical model of the ring of the magnetically coupled oscillators. After this, some basic properties of the model are derived. The dynamical study of the model is carried out in the case of two and three sub-circuits including the phase synchronization, by using the wellknown classical tools, that is, the bifurcation diagrams, the Lyapunov exponents, time series, and phase portraits. It is found that the system displays a rich catalog of behaviors such as regular, chaotic, and hyperchaotic (for a weak coupling) behaviors in terms of the control parameter. Moreover, it is found that the systems exhibit the coexistence of many attractors. The system is shown to exhibit global and partial synchronization (chimera state) in the case of three sub-circuits. Transient chaos/hyperchaos are also highlighted in the two sub-circuits cases. PSPICE based simulations and real laboratory measurements are included and are consistent with the theoretical/numerical results.
查看更多>>摘要：In today's economy, selling a new zero-marginal cost product is a real challenge, as it is difficult to determine a product's "correct" sales price based on its profit and dissemination. As an example, think of the price of a new app or video game. New sales mechanisms for selling this type of product need to be designed, in particular ones that consider consumer preferences and reality. Here we introduce an auction model where buyers continuously place bids and the challenge is to decide whether or not to accept them. The model does not include a deadline for placing bids, and exhibits self-organized criticality; it presents a critical price from which a bid is accepted with probability one, and avalanches of sales above this value are observed. This model is especially interesting for startup companies interested in profit as well as making the product known on the market. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：This paper considers the synchronization problem of memristive neural networks (MNNs) via a fuzzy outputbased adaptive strategy, where the fuzzy model of MNNs with state-dependent memristor is employed. Several adaptive rules for the controller gain of the slave NNs and its connection weights are designed, which provide a new way to realize the state synchronization between master and slaver memristive NNs. Under these adaptive update rules, several synchronization results and their performance analysis are given, which verified by a simulation example. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：In the event that an Arctic oil spill occurs, oil spill modelers need to understand how oil moves along the subsurface of sea ice to predict how a slick will migrate. Currently, modeling the subsurface topography of sea ice has been hampered by a lack of understanding of this complex surface. Using sonar data from the Chukchi Sea, an investigation into whether this subsurface topography exhibited fractal scaling behavior was initiated. It was established that young sea ice exhibits multifractal scaling geometry parameters alpha, c1, and H as 1.2, 0.03, and 0.12, respectively. Fractal scaling behavior was not found for other types of sea ice. Having established such an analysis is useful, future efforts to expand the work are suggested.(c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
查看更多>>摘要：In this paper, we investigate a single population growth model with Beverton-Holt function, which is driven by cross-correlation between multiplicative and additive colored noises. Firstly, using approximate Fokker-Planck equation, the stationary probability distribution of the model is obtained, and then its the shape structure is discussed in detail. In addition, the influence of noise characteristics on mean, variance and skewness is studied numerically. Finally, an explicit expression of the mean first passage time is given by using the steepest-descent approximation. It is found that: (i) the P-bifurcation occurs when the two noises are positively correlated or zero correlated, but not in the case of negative correlation; (ii) a strong negative correlation degree and correlation time can promote population growth, while the strong positive correlation degree plays an opposite role; (iii) the noise enhanced stability induced by multiplicative noise is different from that induced by the additive one. (c) 2022 Elsevier Ltd. All rights reserved.
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