A new discretization scheme is proposed for the design of a fractional order PID controller. In the design of a fractional order controller the interest is mainly focused on the s-domain, but there exists a difficult ...A new discretization scheme is proposed for the design of a fractional order PID controller. In the design of a fractional order controller the interest is mainly focused on the s-domain, but there exists a difficult problem in the s-domain that needs to be solved, i.e. how to calculate fractional derivatives and integrals efficiently and quickly. Our scheme adopts the time domain that is well suited for Z-transform analysis and digital implementation. The main idea of the scheme is based on the definition of Grünwald-Letnicov fractional calculus. In this case some limited terms of the definition are taken so that it is much easier and faster to calculate fractional derivatives and integrals in the time domain or z-domain without loss much of the precision. Its effectiveness is illustrated by discretization of half-order fractional differential and integral operators compared with that of the analytical scheme. An example of designing fractional order digital controllers is included for illustration, in which different fractional order PID controllers are designed for the control of a nonlinear dynamic system containing one of the four different kinds of nonlinear blocks: saturation, deadzone, hysteresis, and relay.展开更多
The permanence of a nonlinear higher order discrete time system from macroeconomics is studied, and a sufficient condition is proposed for the permanence of the system described by 11(,...,)nnnnkxrxfxx---=+ where :kfR...The permanence of a nonlinear higher order discrete time system from macroeconomics is studied, and a sufficient condition is proposed for the permanence of the system described by 11(,...,)nnnnkxrxfxx---=+ where :kfRR, the initial values 01,,kxx-are real numbers and [0,1)r is constant after exploring the relationship between this equation and 1(,...,)nnnkxfxx--= for certain classes of function f. As an application a short proof is given to a known result in a simpler way than ever reported.展开更多
This paper develops an economic production quantity(EPQ)model for a singlemanufacturer multi-retailer(SMMR)production and reworking system with green and environmental sensitive customer demand.The minimum cost of the...This paper develops an economic production quantity(EPQ)model for a singlemanufacturer multi-retailer(SMMR)production and reworking system with green and environmental sensitive customer demand.The minimum cost of the manufacturer has obtained under carbon emissions(CE)policies and discrete ordering cost reduction.The model is used to optimize the total number of shipments,greening investment level,environmental measure,and lot size for productions and rework.This research work determines that the manufacturer’s and retailer’s profits will be increased after considering the environmental and green dependent demand of customers.Further,the development of green and environmental demand is proposed to minimize the CE and maximize the demand for the customers.In the existing literature,no discrete investment is developed for reducing the cost of ordering for the retailer/buyer.However,in this paper,we have introduced it.We provide numerical examples to explain the models and determine the significance of model parameters.展开更多
In this paper we consider the first order discrete Hamiltonian systems {x1（n＋1）-x1（n）=Hx2（n,x（n））,x2（n）-x2（n-1）=Hx1（n,x（n））,where x（n） = （x2（n）x1（n））∑ R^2N, H（n,z） = 1/2S（n）z. z ＋ R（n,z...In this paper we consider the first order discrete Hamiltonian systems {x1（n＋1）-x1（n）=Hx2（n,x（n））,x2（n）-x2（n-1）=Hx1（n,x（n））,where x（n） = （x2（n）x1（n））∑ R^2N, H（n,z） = 1/2S（n）z. z ＋ R（n,z） is periodic in n and superlinear as {z} →4 ∞. We prove the existence and infinitely many （geometrically distinct） homoclonic orbits of the system by critical point theorems for strongly indefinite functionals.展开更多
The problem of the chattering phenomenon is still the main drawback of the classical sliding mode control. To resolve this problem, a discrete second order sliding mode control via input-output model is proposed in th...The problem of the chattering phenomenon is still the main drawback of the classical sliding mode control. To resolve this problem, a discrete second order sliding mode control via input-output model is proposed in this paper. The proposed control law is synthesized for decouplable multivariable systems. A robustness analysis of the proposed discrete second order sliding mode control is carried out. Simulation results are presented to illustrate the effectiveness of the proposed strategy.展开更多
By optimizing pump power ratio between 1st order backward pump and 2nd order forward pump on discrete Raman amplifier, we demonstrated over 2dB noise figure improvement without excessive non-linearity degradation.
In this paper,we explore a new approach to design and analyze numerical schemes for backward stochastic differential equations(BSDEs).By the nonlinear Feynman-Kac formula,we reformulate the BSDE into a pair of referen...In this paper,we explore a new approach to design and analyze numerical schemes for backward stochastic differential equations(BSDEs).By the nonlinear Feynman-Kac formula,we reformulate the BSDE into a pair of reference ordinary differential equations(ODEs),which can be directly discretized by many standard ODE solvers,yielding the corresponding numerical schemes for BSDEs.In particular,by applying strong stability preserving(SSP)time discretizations to the reference ODEs,we can propose new SSP multistep schemes for BSDEs.Theoretical analyses are rigorously performed to prove the consistency,stability and convergency of the proposed SSP multistep schemes.Numerical experiments are further carried out to verify our theoretical results and the capacity of the proposed SSP multistep schemes for solving complex associated problems.展开更多
Towards the end of 2019,the world witnessed the outbreak of Severe Acute Respiratory Syndrome Coronavirus-2(COVID-19),a new strain of coronavirus that was unidentified in humans previously.In this paper,a new fraction...Towards the end of 2019,the world witnessed the outbreak of Severe Acute Respiratory Syndrome Coronavirus-2(COVID-19),a new strain of coronavirus that was unidentified in humans previously.In this paper,a new fractional-order Susceptible-Exposed-Infected-Hospitalized-Recovered(SEIHR)model is formulated for COVID-19,where the population is infected due to human transmission.The fractional-order discrete version of the model is obtained by the process of discretization and the basic reproductive number is calculated with the next-generation matrix approach.All equilibrium points related to the disease transmission model are then computed.Further,sufficient conditions to investigate all possible equilibria of the model are established in terms of the basic reproduction number(local stability)and are supported with time series,phase portraits and bifurcation diagrams.Finally,numerical simulations are provided to demonstrate the theoretical findings.展开更多
In this article,we present two new novel finite difference approximations of order two and four,respectively,for the three dimensional non-linear triharmonic partial differential equations on a compact stencil where t...In this article,we present two new novel finite difference approximations of order two and four,respectively,for the three dimensional non-linear triharmonic partial differential equations on a compact stencil where the values of u,δ^(2)u/δn^(2)andδ^(4)u/δn^(4)are prescribed on the boundary.We introduce new ideas to handle the boundary conditions and there is no need to discretize the derivative boundary conditions.We require only 7-and 19-grid points on the compact cell for the second and fourth order approximation,respectively.The Laplacian and the biharmonic of the solution are obtained as by-product of the methods.We require only system of three equations to obtain the solution.Numerical results are provided to illustrate the usefulness of the proposed methods.展开更多
文摘A new discretization scheme is proposed for the design of a fractional order PID controller. In the design of a fractional order controller the interest is mainly focused on the s-domain, but there exists a difficult problem in the s-domain that needs to be solved, i.e. how to calculate fractional derivatives and integrals efficiently and quickly. Our scheme adopts the time domain that is well suited for Z-transform analysis and digital implementation. The main idea of the scheme is based on the definition of Grünwald-Letnicov fractional calculus. In this case some limited terms of the definition are taken so that it is much easier and faster to calculate fractional derivatives and integrals in the time domain or z-domain without loss much of the precision. Its effectiveness is illustrated by discretization of half-order fractional differential and integral operators compared with that of the analytical scheme. An example of designing fractional order digital controllers is included for illustration, in which different fractional order PID controllers are designed for the control of a nonlinear dynamic system containing one of the four different kinds of nonlinear blocks: saturation, deadzone, hysteresis, and relay.
基金the Technology Research Foundation of the State Ministry of Education (No. 02130)
文摘The permanence of a nonlinear higher order discrete time system from macroeconomics is studied, and a sufficient condition is proposed for the permanence of the system described by 11(,...,)nnnnkxrxfxx---=+ where :kfRR, the initial values 01,,kxx-are real numbers and [0,1)r is constant after exploring the relationship between this equation and 1(,...,)nnnkxfxx--= for certain classes of function f. As an application a short proof is given to a known result in a simpler way than ever reported.
基金supported by University Grants Commission–Special Assistance Program(DSA I)[grant number F.510/7/DSA-I/2015(SAP-I)],Government of India,New Delhi.
文摘This paper develops an economic production quantity(EPQ)model for a singlemanufacturer multi-retailer(SMMR)production and reworking system with green and environmental sensitive customer demand.The minimum cost of the manufacturer has obtained under carbon emissions(CE)policies and discrete ordering cost reduction.The model is used to optimize the total number of shipments,greening investment level,environmental measure,and lot size for productions and rework.This research work determines that the manufacturer’s and retailer’s profits will be increased after considering the environmental and green dependent demand of customers.Further,the development of green and environmental demand is proposed to minimize the CE and maximize the demand for the customers.In the existing literature,no discrete investment is developed for reducing the cost of ordering for the retailer/buyer.However,in this paper,we have introduced it.We provide numerical examples to explain the models and determine the significance of model parameters.
基金CHEN WenXiong supported by Science Foundation of Huaqiao UniversityYANG Minbo was supported by Natural Science Foundation of Zhejiang Province (Grant No. Y7080008)+1 种基金YANG Minbo was supported by National Natural Science Foundation of China (Grant No. 11101374, 10971194)DING Yanheng was supported partially by National Natural Science Foundation of China (Grant No. 10831005)
文摘In this paper we consider the first order discrete Hamiltonian systems {x1（n＋1）-x1（n）=Hx2（n,x（n））,x2（n）-x2（n-1）=Hx1（n,x（n））,where x（n） = （x2（n）x1（n））∑ R^2N, H（n,z） = 1/2S（n）z. z ＋ R（n,z） is periodic in n and superlinear as {z} →4 ∞. We prove the existence and infinitely many （geometrically distinct） homoclonic orbits of the system by critical point theorems for strongly indefinite functionals.
基金supported by the Ministry of Higher Education and Scientific Research in Tunisia
文摘The problem of the chattering phenomenon is still the main drawback of the classical sliding mode control. To resolve this problem, a discrete second order sliding mode control via input-output model is proposed in this paper. The proposed control law is synthesized for decouplable multivariable systems. A robustness analysis of the proposed discrete second order sliding mode control is carried out. Simulation results are presented to illustrate the effectiveness of the proposed strategy.
文摘By optimizing pump power ratio between 1st order backward pump and 2nd order forward pump on discrete Raman amplifier, we demonstrated over 2dB noise figure improvement without excessive non-linearity degradation.
基金supported by the National Natural Science Foundations of China(Grant Nos.12071261,11831010)the National Key R&D Program(Grant No.2018YFA0703900).
文摘In this paper,we explore a new approach to design and analyze numerical schemes for backward stochastic differential equations(BSDEs).By the nonlinear Feynman-Kac formula,we reformulate the BSDE into a pair of reference ordinary differential equations(ODEs),which can be directly discretized by many standard ODE solvers,yielding the corresponding numerical schemes for BSDEs.In particular,by applying strong stability preserving(SSP)time discretizations to the reference ODEs,we can propose new SSP multistep schemes for BSDEs.Theoretical analyses are rigorously performed to prove the consistency,stability and convergency of the proposed SSP multistep schemes.Numerical experiments are further carried out to verify our theoretical results and the capacity of the proposed SSP multistep schemes for solving complex associated problems.
基金supported by the research project:Modeling and Stability Analysis of the Spread of Novel Coronavirus Disease COVID-19Prince Sultan University,Saudi Arabia[grant number COVTD19-DES-2020-66].
文摘Towards the end of 2019,the world witnessed the outbreak of Severe Acute Respiratory Syndrome Coronavirus-2(COVID-19),a new strain of coronavirus that was unidentified in humans previously.In this paper,a new fractional-order Susceptible-Exposed-Infected-Hospitalized-Recovered(SEIHR)model is formulated for COVID-19,where the population is infected due to human transmission.The fractional-order discrete version of the model is obtained by the process of discretization and the basic reproductive number is calculated with the next-generation matrix approach.All equilibrium points related to the disease transmission model are then computed.Further,sufficient conditions to investigate all possible equilibria of the model are established in terms of the basic reproduction number(local stability)and are supported with time series,phase portraits and bifurcation diagrams.Finally,numerical simulations are provided to demonstrate the theoretical findings.
基金This research was supported by’The University of Delhi’under research grant No.Dean(R)/R&D/2010/1311.
文摘In this article,we present two new novel finite difference approximations of order two and four,respectively,for the three dimensional non-linear triharmonic partial differential equations on a compact stencil where the values of u,δ^(2)u/δn^(2)andδ^(4)u/δn^(4)are prescribed on the boundary.We introduce new ideas to handle the boundary conditions and there is no need to discretize the derivative boundary conditions.We require only 7-and 19-grid points on the compact cell for the second and fourth order approximation,respectively.The Laplacian and the biharmonic of the solution are obtained as by-product of the methods.We require only system of three equations to obtain the solution.Numerical results are provided to illustrate the usefulness of the proposed methods.
