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A novel nonlinear fractional order damped Pantographs equation involving input delay is formulated. We explored the controllability of the underlying nonlinear damped dynamical Pantograph equation of fractional order with input delay. The solution of the problem under consideration has initially expressed in the form of the Mittag–Leffler function in two different domains. The controllability Grammians matrices for both cases have been defined. Controllability in the linear case has been shown and applied Schaefer’s fixed point theorem as well as the Arzela-Ascoli theorem to derive necessary conditions for the controllability of the nonlinear case.

In this paper, we investigate gross domestic product model with four different fractional derivatives. We find the solutions of fractional models by utilizing Sumudu transform. We prove the efficiency of the Sumudu transform by some theoretic outcomes and applications. We demonstrate the simulations by some figures. We show the agreement of different fractional derivatives on the model.

In this work, a nonlinear integral resonant controller is utilized for the first time to suppress the principal parametric excitation of a nonlinear dynamical system. The whole system is modeled as a second-order nonlinear differential equation (i.e., main system) coupled to a nonlinear first-order differential equation (i.e., controller). The control loop time-delays are included in the studied model. The multiple scales homotopy approach is employed to obtain an approximate solution for the proposed time-delayed dynamical system. The nonlinear algebraic equation that governs the steady-state oscillation amplitude has been extracted. The effects of the time-delays, control gain, and feedback gains on the performance of the suggested controller have been investigated. The obtained results indicated that the controller performance depends on the product of the control and feedback signal gains as well as the sum of the time-delays in the control loop. Accordingly, two simple objective functions have been derived to design the optimum values of the loop-delays, control gain, and feedback gains in such a way that enhances the efficiency of the proposed controller. The analytical and numerical simulations illustrated that the proposed controller could eliminate the system vibrations effectively at specific values of the control and feedback signal gains. In addition, the selection method of the loop-delays that either enhances the control performance or destabilizes the system motion has been explained in detail.

Infectious diseases are the major source of increasing death rate during recent years. Among the infectious diseases, dengue fever is disseminated in more than hundred countries, especially in tropical and subtropical regions. In this work, a novel fractional model is presented which describes the dynamics of dengue including human and vector (mosquitoes) population. The mathematical model of dengue transmission is important to understand the dynamical behavior of the disease. A compartmental model of the dengue transmission is composed of five compartments representing the human and mosquito dynamics. The model is solved by using Adams-Bashforth-Moulton technique. The simulated results are compared with four years (2011–2014) real time data of dengue cases in Lahore, Pakistan. The fractional model gives a better approximation for α = 0.8 as compared to α = 1. The reasonable range of fractional order is between α = 0.7 and α = 1. The stability analysis of the equilibria is presented. Moreover, the positivity of the solution is proved. Furthermore, the parametric study using the outbreak dengue data for Lahore is presented. On the basis of results, we conclude that the fractional order model is more suitable than integer order equations to evaluate the transmission of dengue disease. The present study plays an important role in studying the factors to remove the communicable diseases like dengue.