In this paper,a discrete-time SIR epidemic model with nonlinear incidence and recovery rates is obtained by using the forward Euler’s method.The existence and stability of fixed points in this model are well studied....In this paper,a discrete-time SIR epidemic model with nonlinear incidence and recovery rates is obtained by using the forward Euler’s method.The existence and stability of fixed points in this model are well studied.The center manifold theorem and bifurcation theory are applied to analyze the bifurcation properties by using the discrete time step and the intervention level as control parameters.We discuss in detail some codimension-one bifurcations such as transcritical,period-doubling and Neimark–Sacker bifurcations,and a codimension-two bifurcation with 1:2 resonance.In addition,the phase portraits,bifurcation diagrams and maximum Lyapunov exponent diagrams are drawn to verify the correctness of our theoretical analysis.It is found that the numerical results are consistent with the theoretical analysis.More interestingly,we also found other bifurcations in the model during the numerical simulation,such as codimension-two bifurcations with 1:1 resonance,1:3 resonance and 1:4 resonance,generalized period-doubling and fold-flip bifurcations.The results show that the dynamics of the discrete-time model are richer than that of the continuous-time SIR epidemic model.Such a discrete-time model may not only be widely used to detect the pathogenesis of infectious diseases,but also make a great contribution to the prevention and control of infectious diseases.展开更多
This paper studies the symmetry of a class of tractional Sturm-Liouville differential equations with right and left fractional derivatives. We give the Hermitian boundary condition description of this problem. Further...This paper studies the symmetry of a class of tractional Sturm-Liouville differential equations with right and left fractional derivatives. We give the Hermitian boundary condition description of this problem. Furthermore, the density of minimal operator is given. Then the symmetry of this problem is obtained.展开更多
Some new generalized retarded nonlinear integral inequalities are discussed and upper bound estimations of unknown functions are given by adapting novel analysis techniques. These estimations can be applied to study d...Some new generalized retarded nonlinear integral inequalities are discussed and upper bound estimations of unknown functions are given by adapting novel analysis techniques. These estimations can be applied to study differential-integral equations and some practical problems in engineering.展开更多
基金supported by the NSF of Shandong Province(ZR2021MA016,ZR2019MA034,ZR2018BF018)the China Postdoctoral Science Foundation(2019M652349)the Youth Creative Team Sci-Tech Program of Shandong Universities(2019KJI007).
文摘In this paper,a discrete-time SIR epidemic model with nonlinear incidence and recovery rates is obtained by using the forward Euler’s method.The existence and stability of fixed points in this model are well studied.The center manifold theorem and bifurcation theory are applied to analyze the bifurcation properties by using the discrete time step and the intervention level as control parameters.We discuss in detail some codimension-one bifurcations such as transcritical,period-doubling and Neimark–Sacker bifurcations,and a codimension-two bifurcation with 1:2 resonance.In addition,the phase portraits,bifurcation diagrams and maximum Lyapunov exponent diagrams are drawn to verify the correctness of our theoretical analysis.It is found that the numerical results are consistent with the theoretical analysis.More interestingly,we also found other bifurcations in the model during the numerical simulation,such as codimension-two bifurcations with 1:1 resonance,1:3 resonance and 1:4 resonance,generalized period-doubling and fold-flip bifurcations.The results show that the dynamics of the discrete-time model are richer than that of the continuous-time SIR epidemic model.Such a discrete-time model may not only be widely used to detect the pathogenesis of infectious diseases,but also make a great contribution to the prevention and control of infectious diseases.
文摘This paper studies the symmetry of a class of tractional Sturm-Liouville differential equations with right and left fractional derivatives. We give the Hermitian boundary condition description of this problem. Furthermore, the density of minimal operator is given. Then the symmetry of this problem is obtained.
基金supported by the NNSF of China(Grants 11171178 and 11271225)program for scientific research innovation team in colleges and universities of Shandong Province,scientific research training project for talent students(201310446008)
文摘Some new generalized retarded nonlinear integral inequalities are discussed and upper bound estimations of unknown functions are given by adapting novel analysis techniques. These estimations can be applied to study differential-integral equations and some practical problems in engineering.
