Browsing by Author "Macau, Elbert Einstein Nehrer"

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    Complex networks approach for dynamical characterization of nonlinear systems.
    (2019) Freitas, Vander Luis de Souza; Lacerda, Juliana Cestari; Macau, Elbert Einstein Nehrer
    Bifurcation diagrams and Lyapunov exponents are the main tools for dynamical systems char- acterization. However, they are often computationally expensive and complex to calculate. We present two approaches for dynamical characterization of nonlinear systems via the generation of an undirected complex network that is built from their time series. Periodic windows and chaos can be detected by analyzing network statistics like average degree, density and betweenness centrality. Results are assessed in two discrete time nonlinear maps.
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    Synchronization-based symmetric circular formations of mobile agents and the generation of chaotic trajectories.
    (2021) Freitas, Vander Luis de Souza; Yanchuk, Serhiy; Zaks, Michael; Macau, Elbert Einstein Nehrer
    The self-organization of multiple autonomous mobile agents is a trending topic nowadays with applications in robotics, aerospace engineering, and satellite formations. We investigate a model of particles with coupled-oscillators dynamics focusing on the particular case of agents grouping in symmetric clusters while moving in concentric circular trajectories. Our results reveal that certain regions of the parameter space are more suitable for the onset of such clusters. Additionally, we study the effects of adding and removing agents from already formed clusters, prescribe a strategy to properly switch from one formation to another, and finally introduce an approach to obtain chaotic almost-circular trajectories and symmetric clusters with non-overlapping particles.
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    The effects of time-delay and phase lags on symmetric circular formations of mobile agents.
    (2021) Freitas, Vander Luis de Souza; Yanchuk, Serhiy; Grande, Helder Luciani Casa; Macau, Elbert Einstein Nehrer
    The mobile agents’ circular formation problem is driven by applications that require a desired spatial and temporal separation, such as data collection or satellite constellations. There are numerous strategies to assign the cluster number and spacing, the radius of the trajectory, communication network, and other parameters. In this numerical study, we are particularly interested in the effects of time-delay and phase lag on circular formations with symmetric clusters in a first-order model with all-to-all interaction. When the information exchange time-delay exceeds some critical value, it leads to either incoherent or alternative symmetric arrangements. Besides, we show that formations can be effectively controlled using phase lags. As a paradigmatic example, we consider identical phase lags for half of the agents, while the other half receives an opposite phase lag. As a result, the system reaches more complicated stable arrangements. For instance, the agents can split into asymmetric clusters, each of them creating a symmetric formation.