ABSTRACT Disruptions of the circadian rhythm are associated with internal desynchronization. It affects some internal functions of our body and behavior that are important to our health. Our modern lifestyle has contributed to millions of people developing some circadian rhythm disruptions, making the subject very important clinically as well as economically. Motivated by studying a simple mathematical model that can reveal some features of internal synchronization/desynchronization, in this contribution, we extend the coupling oscillator phase model proposed by Strogatz14 in the sense that memory is considered in the modeling. Such memory is a result of the introduction of Caputo-type fractional derivatives in the coupling oscillators’ phase model dynamics, resulting in a fractional phase model. We show that the proposed fractional coupling oscillator phase model is well-posed. Furthermore, we analyze the synchronization phenomena. We obtain the synchronized solutions explicitly when the memory is equally distributed between the oscillators. In contrast, when distinct levels of memory are imposed in the modeling, we obtain lower and upper bounds because any existing synchronized solution must be confined in between. We present numerical realizations that support the theoretical findings in great detail. desynchronization health disruptions economically synchronizationdesynchronization synchronization/desynchronization contribution Strogatz Strogatz1 modeling Caputotype Caputo type oscillators dynamics wellposed. wellposed posed. posed well-posed Furthermore phenomena contrast detail

RESUMO Nesta contribuição analisaremos o problema inverso de identificação do coeficiente de rigidez em vigas modeladas pela equação de Euler-Bernoulli, a partir de medidas da deflexão. Apresentaremos o problema na forma de uma equação de operador parâmetro-para-medidas, para o qual, provaremos propriedades importantes, como compacidade e continuidade. Mostraremos ainda que o operador parâmetropara-medidas é Fréchet diferenciável e que satisfaz a condição do cone tangente. Essas propriedades são suficientes para recuperarmos de forma estável e convergente (método de regularização) o coeficiente de rigidez através de métodos iterativos como Landweber e Steepest descent. Por fim, apresentamos os efeitos de estabilidade das soluções aproximadas com relação as medidas com diferentes níveis de ruídos, através de exemplos numéricos.

ABSTRACT In this contribution, we analyze the identifiability of the stiffness coefficient inverse problem in beams modeled by the Euler-Bernoulli equation, from measurements of the beam deflection. We present the problem in the form of a parameter-to-measure operator equation, for which we prove important properties, such as compactness and continuity. We also show that the parameter-to-measure operator is Fréchet differentiable and that it satisfies the tangential cone condition. These properties are sufficient to recover in a stable and convergent way (regularization method) the stiffness coefficient through iterative methods such as Landweber and Steepest descent. Finally, we present the stability effects of the approximate solutions concerning measurements with different noise levels through numerical examples.