731 citations · 12.8k across the 413 of their papers we have counts for
256 papers · 1 filter
An Analytic Method to Determine the Optimal Time for the Induction Phase of Anesthesia
Mohamed A. Zaitri, Cristiana J. Silva, Delfim F. M. Torres
We obtain an analytical solution for the time-optimal control problem in the induction phase of anesthesia. Our solution is shown to align numerically with the results obtained fro…
Optimal control for a nonlinear stochastic PDE model of cancer growth
Sakine Esmaili, M. R. Eslahchi, Delfim F. M. Torres
We study an optimal control problem for a stochastic model of tumour growth with drug application. This model consists of three stochastic hyperbolic equations describing the evolu…
Dynamics of a Double-Impulsive Control Model of Integrated Pest Management Using Perturbation Methods and Floquet Theory
Fahad Al Basir, Jahangir Chowdhury, Delfim F. M. Torres
We formulate an integrated pest management model to control natural pests of the crop through the periodic application of biopesticide and chemical pesticides. In a theoretical ana…
Numerical Fractional Optimal Control of Respiratory Syncytial Virus Infection in Octave/MATLAB
Silverio Rosa, Delfim F. M. Torres
In this article, we develop a simple mathematical GNU Octave/MATLAB code that is easy to modify for the simulation of mathematical models governed by fractional-order differential…
Existence, uniqueness and controllability for Hilfer differential equations on times scales
J. Vanterler da C. Sousa, D. S. Oliveira, Gastao S. F. Frederico +1
We introduce a new version of -Hilfer fractional derivative, on an arbitrary time scale. The fundamental properties of the new operator are investigated and, in particular, we p…
Approximate Controllability of Delayed Fractional Stochastic Differential Systems with Mixed Noise and Impulsive Effects
Naima Hakkar, Rajesh Dhayal, Amar Debbouche +1
We herein report a new class of impulsive fractional stochastic differential systems driven by mixed fractional Brownian motions with infinite delay and Hurst parameter $\hat{\cal…
Regional Gradient Observability for Fractional Differential Equations with Caputo Time-Fractional Derivatives
Khalid Zguaid, Fatima-Zahrae El Alaoui, Delfim F. M. Torres
We investigate the regional gradient observability of fractional sub-diffusion equations involving the Caputo derivative. The problem consists of describing a method to find and re…
Regional Controllability and Minimum Energy Control of Delayed Caputo Fractional-Order Linear Systems
Touria Karite, Adil Khazari, Delfim F. M. Torres
We study the regional controllability problem for delayed fractional control systems through the use of the standard Caputo derivative. First, we recall several fundamental results…
Near-optimal control of a stochastic SICA model with imprecise parameters
Houssine Zine, Delfim F. M. Torres
An adequate near-optimal control problem for a stochastic SICA (Susceptible-Infected-Chronic-AIDS) compartmental epidemic model for HIV transmission with imprecise parameters is fo…
Comment on "Noether's-type theorems on time scales" [J. Math. Phys. 61, 113502 (2020)]
Delfim F. M. Torres
We comment on the validity of Noether's theorem and on the conclusions of [J. Math. Phys. 61 (2020), no. 11, 113502].
Minimum Energy Problem in the Sense of Caputo for Fractional Neutral Evolution Systems in Banach Spaces
Zoubida Ech-chaffani, Ahmed Aberqi, Touria Karite +1
We investigate a class of fractional neutral evolution equations on Banach spaces involving Caputo derivatives. Main results establish conditions for the controllability of the fra…
Mathematical Analysis, Forecasting and Optimal Control of HIV/AIDS Spatiotemporal Transmission with a Reaction Diffusion SICA Model
Houssine Zine, Abderrahim El Adraoui, Delfim F. M. Torres
We propose a mathematical spatiotemporal epidemic SICA model with a control strategy. The spatial behavior is modeled by adding a diffusion term with the Laplace operator, which is…
A SIQRB delayed model for cholera and optimal control treatment
Ana P. Lemos-Paiao, Helmut Maurer, Cristiana J. Silva +1
We improve a recent mathematical model for cholera by adding a time delay that represents the time between the instant at which an individual becomes infected and the instant at wh…
Weighted Generalized Fractional Integration by Parts and the Euler-Lagrange Equation
Houssine Zine, El Mehdi Lotfi, Delfim F. M. Torres +1
Integration by parts plays a crucial role in mathematical analysis, e.g., during the proof of necessary optimality conditions in the calculus of variations and optimal control. Mot…
Fractional Modelling and Optimal Control of COVID-19 Transmission in Portugal
Silverio Rosa, Delfim F. M. Torres
A fractional-order compartmental model was recently used to describe real data of the first wave of the COVID-19 pandemic in Portugal [Chaos Solitons Fractals 144 (2021), Art. 1106…
Transport and Optimal Control of Vaccination Dynamics for COVID-19
Mohamed Abdelaziz Zaitri, Mohand Ouamer Bibi, Delfim F. M. Torres
We develop a mathematical model for transferring the vaccine BNT162b2 based on the heat diffusion equation. Then, we apply optimal control theory to the proposed generalized SEIR m…
Fractional-Order Modelling and Optimal Control of Cholera Transmission
Silverio Rosa, Delfim F. M. Torres
A Caputo-type fractional-order mathematical model for "metapopulation cholera transmission" was recently proposed in [Chaos Solitons Fractals 117 (2018), 37--49]. A sensitivity ana…
Optimal control of a heroin epidemic mathematical model
Puthur Thangaraj Sowndarrajan, Lingeshwaran Shangerganesh, Amar Debbouche +1
A heroin epidemic mathematical model with prevention information and treatment, as control interventions, is analyzed, assuming that an individual's behavioral response depends on…
Model-free based control of a HIV/AIDS prevention model
Loïc Michel, Cristiana J. Silva, Delfim F. M. Torres
Controlling an epidemiological model is often performed using optimal control theory techniques for which the solution depends on the equations of the control system, objective fun…
Optimal Control Problems Involving Combined Fractional Operators with General Analytic Kernels
Faical Ndairou, Delfim F. M. Torres
Fractional optimal control problems via a wide class of fractional operators with a general analytic kernel are introduced. Necessary optimality conditions of Pontryagin type for t…
Controlling crop pest with a farming awareness based integrated approach and optimal control
Teklebirhan Abraha, Fahad Al Basir, Legesse Lemecha Obsu +1
We investigate a mathematical model in crop pest controlling, considering plant biomass, pest, and the effect of farming awareness. The pest population is divided into two compartm…
Weak Pontryagin's Maximum Principle for Optimal Control Problems Involving a General Analytic Kernel
Faical Ndairou, Delfim F. M. Torres
We prove a duality relation and an integration by parts formula for fractional operators with a general analytical kernel. Based on these basic results, we are able to prove a new…
Pontryagin Maximum Principle for Distributed-Order Fractional Systems
Faical Ndairou, Delfim F. M. Torres
We consider distributed-order non-local fractional optimal control problems with controls taking values on a closed set and prove a strong necessary optimality condition of Pontrya…
Optimal Control to Limit the Spread of COVID-19 in Italy
Mohamed Abdelaziz Zaitri, Mohand Ouamer Bibi, Delfim F. M. Torres
We apply optimal control theory to a generalized SEIR-type model. The proposed system has three controls, representing social distancing, preventive means, and treatment measures t…