3,395 results
Search Results
2. Nonlinear optimal control for permanent magnet synchronous spherical motors
- Author
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Rigatos, Gerasimos G., Abbaszadeh, Masoud, Siano, Pierluigi, and Pomares, Jorge
- Published
- 2023
- Full Text
- View/download PDF
3. Global dynamics of a Lotka-Volterra competition-diffusion system with advection and nonlinear boundary conditions.
- Author
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Tian, Chenyuan and Guo, Shangjiang
- Subjects
NONLINEAR systems ,EIGENVALUES - Abstract
In this paper, we deal with the global dynamics of a Lotka-Volterra competition-diffusion-advection system with nonlinear boundary conditions, including the existence, nonexistence and global stability of coexistence steady states. We start with the investigation of the principal eigenvalue of linearized system to get the local stability of steady states and then discuss the global dynamics in terms of competition coefficients. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. ON TRACKING AND ANTIDISTURBANCE ABILITY OF PID CONTROLLERS.
- Author
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CHENG ZHAO and SHUO YUAN
- Subjects
PID controllers ,STOCHASTIC systems ,NONLINEAR functions ,RANDOM noise theory ,ARTIFICIAL satellite tracking ,NONLINEAR systems - Abstract
In this paper, we are concerned with the tracking performance and antidisturbance ability of the widely used proportional-integral-derivative (PID) controllers in practice. Towards this end, we consider a basic class of second-order nonlinear stochastic control systems subject to model uncertainties and external disturbances, and focus on the ability of the classical PID controller to track time-varying reference signals. First, under some suitable conditions on the system nonlinear functions, reference signals, and external disturbances, we show that such control systems can be stabilized in the mean square sense, provided that the three PID gains are selected from a stability region constructed in the paper. Besides, it is shown that the steady-state tracking error has an upper bound proportional to the sum of the varying rates of reference signals, the varying rates of external disturbances, and the intensity of random noises. Meanwhile, its proportional coefficient depends on the selection of PID gains, which can be made arbitrarily small by choosing suitably large PID gains. Finally, by introducing a desired transient process which is shaped from the reference signal, a new PID tuning rule is presented, which can guarantee both the expected steady state and transient tracking performance. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Dynamics analysis of a reaction-diffusion malaria model accounting for asymptomatic carriers.
- Author
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Shi, Yangyang, Chen, Fangyuan, Wang, Liping, and Zhang, Xuebing
- Subjects
BASIC reproduction number ,GLOBAL asymptotic stability ,MALARIA ,BEHAVIORAL assessment ,MALARIA prevention - Abstract
A significant proportion of malaria infections in humans exhibit no symptoms, but it is a reservoir for maintaining malaria transmission. A time periodic reaction-diffusion model for malaria spread is introduced in this paper, incorporating spatial heterogeneity, incubation periods, symptomatic and asymptomatic carriers. This paper introduces the concept of the basic reproduction number R 0 , which is defined as the spectral radius of the next generation operator, and we present some preliminary results by elementary analysis. The threshold dynamic behavior analysis shows that when R 0 < 1 , the disease is extinct, and when R 0 > 1 , the disease is persistent. We investigate the case of constant system parameters, focusing on the global asymptotic stability of the disease-free steady state when R 0 = 1 . In the numerical simulation section, we validate the theoretical results obtained, and then use elasticity analysis methods to explore the influence of parameters on the output solution. In addition, sensitivity analysis of the basic reproduction number under homogeneous conditions indicates direction of controlling malaria transmission. And several control measures are evaluated in the following steps. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Global stability and co-balancing numbers in a system of rational difference equations.
- Author
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Attia, Najmeddine and Ghezal, Ahmed
- Subjects
DIFFERENCE equations ,MATHEMATICAL models ,MACHINE learning ,DIGITAL technology ,ARTIFICIAL intelligence - Abstract
This paper investigates both the local and global stability of a system of rational difference equations and its connection to co-balancing numbers. The study delves into the intricate dynamics of mathematical models and their stability properties, emphasizing the broader implications of global stability. Additionally, the investigation extends to the role of co-balancing numbers, elucidating their significance in achieving equilibrium within the solutions of the rational difference equations. The interplay between global stability and co-balancing numbers forms a foundational aspect of the analysis. The findings contribute to a deeper understanding of the mathematical structures underlying dynamic systems and offer insights into the factors influencing their stability and equilibrium. This article serves as a valuable resource for mathematicians, researchers, and scholars interested in the intersection of global stability and co-balancing sequences in the realm of rational difference equations. Moreover, the presented examples and figures consistently demonstrate the global asymptotic stability of the equilibrium point throughout the paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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7. Quantitative analysis of a fractional order of the $ SEI_{c}\, I_{\eta} VR $ epidemic model with vaccination strategy.
- Author
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Alshareef, Abeer
- Subjects
BASIC reproduction number ,EPIDEMIOLOGICAL models ,VACCINATION ,COMMUNICABLE diseases ,QUANTITATIVE research ,EPIDEMICS - Abstract
This work focused on studying the effect of vaccination rate κ on reducing the outbreak of infectious diseases, especially if the infected individuals do not have any symptoms. We employed the fractional order derivative in this study since it has a high degree of accuracy. Recently, a lot of scientists have been interested in fractional-order models. It is considered a modern direction in the mathematical modeling of epidemiology systems. Therefore, a fractional order of the SEIR epidemic model with two types of infected groups and vaccination strategy was formulated and investigated in this paper. The proposed model includes the following classes: susceptible S (t) , exposed E (t) , asymptomatic infected I c (t) , symptomatic infected I η (t) , vaccinated V (t) , and recovered R (t) . We began our study by creating the existence, non-negativity, and boundedness of the solutions of the proposed model. Moreover, we established the basic reproduction number R 0 , that was used to examine the existence and stability of the equilibrium points for the presented model. By creating appropriate Lyapunov functions, we proved the global stability of the free-disease equilibrium point and endemic equilibrium point. We concluded that the free-disease equilibrium point is globally asymptotically stable (GAS) when R 0 ≤ 1 , while the endemic equilibrium point is GAS if R 0 > 1 . Therefore, we indicated the increasing vaccination rate κ leads to reducing R 0 . These findings confirm the important role of vaccination rate κ in fighting the spread of infectious diseases. Moreover, the numerical simulations were introduced to validate theoretical results that are given in this work by applying the predictor-corrector PECE method of Adams-Bashforth-Moulton. Further more, the impact of the vaccination rate κ was explored numerically and we found that, as κ increases, the R 0 is decreased. This means the vaccine can be useful in reducing the spread of infectious diseases. This work focused on studying the effect of vaccination rate on reducing the outbreak of infectious diseases, especially if the infected individuals do not have any symptoms. We employed the fractional order derivative in this study since it has a high degree of accuracy. Recently, a lot of scientists have been interested in fractional-order models. It is considered a modern direction in the mathematical modeling of epidemiology systems. Therefore, a fractional order of the SEIR epidemic model with two types of infected groups and vaccination strategy was formulated and investigated in this paper. The proposed model includes the following classes: susceptible , exposed , asymptomatic infected , symptomatic infected , vaccinated , and recovered . We began our study by creating the existence, non-negativity, and boundedness of the solutions of the proposed model. Moreover, we established the basic reproduction number , that was used to examine the existence and stability of the equilibrium points for the presented model. By creating appropriate Lyapunov functions, we proved the global stability of the free-disease equilibrium point and endemic equilibrium point. We concluded that the free-disease equilibrium point is globally asymptotically stable (GAS) when , while the endemic equilibrium point is GAS if . Therefore, we indicated the increasing vaccination rate leads to reducing . These findings confirm the important role of vaccination rate in fighting the spread of infectious diseases. Moreover, the numerical simulations were introduced to validate theoretical results that are given in this work by applying the predictor-corrector PECE method of Adams-Bashforth-Moulton. Further more, the impact of the vaccination rate was explored numerically and we found that, as increases, the is decreased. This means the vaccine can be useful in reducing the spread of infectious diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Dynamics in a delayed rumor propagation model with logistic growth and saturation incidence.
- Author
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Rongrong Yin and Muhammadhaji, Ahmadjan
- Subjects
BASIC reproduction number ,GLOBAL asymptotic stability ,RUMOR ,INFECTIOUS disease transmission - Abstract
This paper studies a delayed rumor propagation model with logistic growth and saturation incidence. The next generation matrix method, some inequality techniques, the Lyapunov-LaSalle invariance principle, and the Lyapunov method are used in this paper. Our results indicate that if the basic regeneration number (which is analogous to the basic reproduction number in disease transmission models) is less than 1, the rumor-free equilibrium point (which is analogous to the disease-free equilibrium point in disease transmission models) is globally stable. If the basic regeneration number is greater than 1, then the rumor is permanent, and some sufficient conditions are obtained for local and global asymptotic stability of the rumor prevailing equilibrium point (which is analogous to the endemic equilibrium point in disease transmission models). Finally, three examples with numerical simulations are presented to illustrate the obtained theoretical results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Distributed event-triggered adaptive robust platoon control of connected vehicles with uncertainties subject to invalid communication
- Author
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Zhao, Rongchen, Liu, Guichuan, Wang, Guangwei, and Zhao, Jin
- Published
- 2023
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10. Dynamical Analysis of an Allelopathic Phytoplankton Model with Fear Effect.
- Author
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Chen, Shangming, Chen, Fengde, Srivastava, Vaibhava, and Parshad, Rana D.
- Abstract
This paper is the first to propose an allelopathic phytoplankton competition ODE model influenced by the fear effect based on natural biological phenomena. It is shown that the interplay of this fear effect and the allelopathic term cause rich dynamics in the proposed competition model, such as global stability, transcritical bifurcation, pitchfork bifurcation, and saddle-node bifurcation. We also consider the spatially explicit version of the model and prove analogous results. Numerical simulations verify the feasibility of the theoretical analysis. The results demonstrate that the primary cause of the extinction of non-toxic species is the fear of toxic species compared to toxins. Allelopathy only affects the density of non-toxic species. The discussion guides the conservation of species and the maintenance of biodiversity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. A fractional SIS model for a random process about infectivity and recovery.
- Author
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Chen, Hui, Li, Jia, and Tan, Xuewen
- Subjects
- *
CONTINUOUS time models , *RANDOM walks , *STOCHASTIC processes , *COMMUNICABLE diseases , *INFECTIOUS disease transmission - Abstract
This paper establishes a new fractional frSIS model utilizing a continuous time random walk method. There are two main innovations in this paper. On the one hand, the model is analyzed from a mathematical perspective. First, unlike the classic SIS infectious disease model, this model presents the infection rate and cure rate in a fractional order. Then, we proved the basic regeneration number R0 of the model and studied the influence of orders
a andb on R0. Second, we found that frSIS has a disease-free equilibrium point E0 and an endemic equilibrium point E∗. Moreover, we proved frSIS global stability of the model using R0. If R0<1, the model of E0 is globally asymptotically stable. If R0>1, the model of E∗ is globally asymptotically stable. On the other hand, from the perspective of infectious diseases, we discovered that appropriately increasinga and decreasingb are beneficial for controlling the spread of diseases and ultimately leading to their disappearance. This can help us provide some dynamic adjustments in prevention and control measures based on changes in the disease. [ABSTRACT FROM AUTHOR]- Published
- 2024
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12. Steady-state bifurcations of a diffusive–advective predator–prey system with hostile boundary conditions and spatial heterogeneity.
- Author
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Liu, Di, Salmaniw, Yurij, Wang, Hao, and Jiang, Weihua
- Subjects
PREDATION ,BIFURCATION theory ,HETEROGENEITY ,ADVECTION ,ADVECTION-diffusion equations ,EIGENVALUES - Abstract
In this paper, we consider a diffusive–advective predator–prey system in a spatially heterogeneous environment subject to a hostile boundary condition, where the interaction term is governed by a Holling type II functional response. We investigate the existence and global attractivity of both trivial and semi-trivial steady-state solutions and the existence and local stability of coexistence steady-state solutions, depending on the size of a key principal eigenvalue. In addition, we show that the effect of advection on the principal eigenvalue is monotonic for small advection rates, depending on the concavity of the resource distribution. For arbitrary advection rates, we consider two explicit resource distributions for which we can say precisely the behaviour of the principal eigenvalue as it depends on advection, highlighting that advection can either improve or impair a population's ability to persist, depending on the characteristics of the resource distribution. We present some numerical simulations to demonstrate the outcomes as they depend on the advection rates for the full predator–prey system. These insights highlight the intimate relationship between environmental heterogeneity, directed movement, and the hostile boundary. The methods employed include upper and lower solution techniques, bifurcation theory, spectral analysis, and the comparison principle. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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13. Global asymptotic stability of evolutionary periodic Ricker competition models.
- Author
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Elaydi, Saber, Kang, Yun, and Luís, Rafael
- Subjects
EVOLUTIONARY models - Abstract
This paper is dedicated to Jim Cushing on the occasion of his 80th birthday. It is inspired by his work on evolutionary theory. We investigate the global dynamics of discrete-time phenotypic evolutionary models, both autonomous and periodic. We developed the theory of mixed monotone maps and applied it to show that the positive equilibrium of the autonomous evolutionary Ricker model of single and multi-species is globally asymptotically stable. Then we extend this result to the corresponding evolutionary Ricker model with periodic parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
14. The effect of a psychological scare on the dynamics of the tumor-immune interaction with optimal control strategy.
- Author
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Salih, Rafel Ibrahim, Jawad, Shireen, Dehingia, Kaushik, and Das, Anusmita
- Abstract
Contracting cancer typically induces a state of terror among the individuals who are affected. Exploring how chemotherapy and anxiety work together to affect the speed at which cancer cells multiply and the immune system's response model is necessary to come up with ways to stop the spread of cancer. This paper proposes a mathematical model to investigate the impact of psychological scare and chemotherapy on the interaction of cancer and immunity. The proposed model is accurately described. The focus of the model's dynamic analysis is to identify the potential equilibrium locations. According to the analysis, it is possible to establish three equilibrium positions. The stability analysis reveals that all equilibrium points consistently exhibit stability under the defined conditions. The bifurcations occurring at the equilibrium sites are derived. Specifically, we obtained transcritical, pitchfork, and saddle-node bifurcation. Numerical simulations are employed to validate the theoretical study and ascertain the minimum therapy dosage necessary for eradicating cancer in the presence of psychological distress, thereby mitigating harm to patients. Fear could be a significant contributor to the spread of tumors and weakness of immune functionality. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Global dynamics of a two-species clustering model with Lotka–Volterra competition.
- Author
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Tao, Weirun, Wang, Zhi-An, and Yang, Wen
- Abstract
This paper is concerned with the global dynamics of a two-species Grindrod clustering model with Lotka–Volterra competition. The model takes the advective flux to depend directly upon local population densities without requiring intermediate signals like attractants or repellents to form the aggregation so as to increase the chances of survival of individuals like human populations forming small nucleated settlements. By imposing appropriate boundary conditions, we establish the global boundedness of solutions in two-dimensional bounded domains. Moreover, we prove the global stability of spatially homogeneous steady states under appropriate conditions on system parameters, and show that the rate of convergence to the coexistence steady state is exponential while the rate of convergence to the competitive exclusion steady state is algebraic. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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16. On Stability of a Fractional Discrete Reaction–Diffusion Epidemic Model.
- Author
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Alsayyed, Omar, Hioual, Amel, Gharib, Gharib M., Abualhomos, Mayada, Al-Tarawneh, Hassan, Alsauodi, Maha S., Abu-Alkishik, Nabeela, Al-Husban, Abdallah, and Ouannas, Adel
- Subjects
GLOBAL asymptotic stability ,EPIDEMICS ,RIESZ spaces ,LYAPUNOV functions ,DISCRETE systems - Abstract
This paper considers the dynamical properties of a space and time discrete fractional reaction–diffusion epidemic model, introducing a novel generalized incidence rate. The linear stability of the equilibrium solutions of the considered discrete fractional reaction–diffusion model has been carried out, and a global asymptotic stability analysis has been undertaken. We conducted a global stability analysis using a specialized Lyapunov function that captures the system's historical data, distinguishing it from the integer-order version. This approach significantly advanced our comprehension of the complex stability properties within discrete fractional reaction–diffusion epidemic models. To substantiate the theoretical underpinnings, this paper is accompanied by numerical examples. These examples serve a dual purpose: not only do they validate the theoretical findings, but they also provide illustrations of the practical implications of the proposed discrete fractional system. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
17. Global dynamics of discretemathematical models of tuberculosis.
- Author
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Elaydi, Saber and Lozi, René
- Subjects
DISEASE eradication ,PREVENTIVE medicine ,TUBERCULOSIS ,PUBLIC health ,EQUILIBRIUM - Abstract
In this paper, we develop discrete models of Tuberculosis (TB). This includes SEI endogenous and exogenous models without treatment. These models are then extended to a SEIT model with treatment. We develop two types of net reproduction numbers, one is the traditional R0 which is based on the disease-free equilibrium, and a new net reproduction number R
0 (E*) based on the endemic equilibrium. It is shown that the disease-free equilibrium is globally asymptotically stable if R0 ≤ 1 and unstable if R0 > 1. Moreover, the endemic equilibrium is locally asymptotically stable if R0 (E*) < 1 < R0 . [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
18. Attractors in k-Dimensional Discrete Systems of Mixed Monotonicity.
- Author
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AlSharawi, Ziyad, Cánovas, Jose S., and Kallel, Sadok
- Abstract
We consider k-dimensional discrete-time systems of the form x n + 1 = F (x n , … , x n - k + 1) in which the map F is continuous and monotonic in each one of its arguments. We define a partial order on R + 2 k , compatible with the monotonicity of F, and then use it to embed the k-dimensional system into a 2k-dimensional system that is monotonic with respect to this poset structure. An analogous construction is given for periodic systems. Using the characteristics of the higher-dimensional monotonic system, global stability results are obtained for the original system. Our results apply to a large class of difference equations that are pertinent in a variety of contexts. As an application of the developed theory, we provide two examples that cover a wide class of difference equations, and in a subsequent paper, we provide additional applications of general interest. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Global Stability Analysis of CHIKV Dynamics Model with Adaptive Immunity and Distributed Time Delays.
- Author
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Alade, Taofeek O., Olaniyi, Samson, Idris, Hassan A., Al Rahbi, Yaqoob, and Alnegga, Mohammad
- Subjects
CHIKUNGUNYA virus ,LYAPUNOV stability ,DYNAMICAL systems ,VIRUS diseases ,IMMUNE response - Abstract
The application of mathematical biology and dynamical systems has proven to be an effective approach for studying viral infection models. To contribute to this research, our paper proposes a new CHIKV model that takes into account an adaptive immune response and distributed time delays, which accurately reflects the time lag between initial viral contacts and the production of new active CHIKV particles. By analyzing the model’s qualitative behavior, we establish a biological threshold number that can predict whether CHIKV will be cleared from or persist in the body. We demonstrate the global stability of both CHIKV-present and CHIKV-free steady states using the Lyapunov functional method and LaSalle’s invariance principle. In addition, we conduct numerical simulations to examine how time delays can affect the stability of the steady states. Through these simulations, we gain insights into how varying time delays can influence the persistence or clearance of CHIKV within the host. [ABSTRACT FROM AUTHOR]
- Published
- 2024
20. Dynamical analysis of an age-structured SEIR model with relapse.
- Author
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NABTi, Abderrazak
- Subjects
BASIC reproduction number ,LATENT infection ,INFECTIOUS disease transmission ,STABILITY theory ,DIFFERENTIAL equations - Abstract
Mathematical models play a crucial role in controlling and preventing the spread of diseases. Based on the communication characteristics of diseases, it is necessary to take into account some essential epidemiological factors such as the time delay that takes an individual to progress from being latent to become infectious, the infectious age which refers to the duration since the initial infection and the occurrence of reinfection after a period of improvement known as relapse, etc. Moreover, age-structured models serve as a powerful tool that allows us to incorporate age variables into the modeling process to better understand the effect of these factors on the transmission mechanism of diseases. In this paper, motivated by the above fact, we reformulate an SEIR model with relapse and age structure in both latent and infected classes. Then, we investigate the asymptotic behavior of the model by using the stability theory of differential equations. For this purpose, we introduce the basic reproduction number R 0 of the model and show that this threshold parameter completely governs the stability of each equilibrium of the model. Our approach to show global attractivity is based on the fluctuation lemma and Lyapunov functionals method with some results on the persistence theory. The conclusion is that the system has a disease-free equilibrium which is globally asymptotically stable if R 0 < 1 , while it has only a unique positive endemic equilibrium which is globally asymptotically stable whenever R 0 > 1 . Our results imply that early diagnosis of latent infection with decrease in both transmission and relapse rates may lead to control and restrict the spread of disease. The theoretical results are illustrated with numerical simulations, which indicate that the age variable is an essential factor affecting the spread of the epidemic. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. A general degenerate reaction-diffusion model for acid-mediated tumor invasion.
- Author
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Li, Fang, Yao, Zheng-an, and Yu, Ruijia
- Subjects
TUMORS ,FUNCTIONALS - Abstract
In this paper, we continue the research in Li et al. (J Differ Equ 371:353–395, 2023) and study the linear and global stability of a class of reaction-diffusion systems with general degenerate diffusion. The establishment of these systems is based on the acid-mediated invasion hypothesis, which is a candidate explanation for the Warburg effect. Our theoretical results characterize the effects of acid resistance and mutual competition between healthy cells and tumor cells on local and long-term tumor development, i.e., whether the healthy cells and tumor cells coexist or the tumor cells prevail after tumor invasion. We first consider the linear stability of the steady states and give a complete characterization by transforming the linearized analysis into an algebraic problem. In discussing global stability, the main difficulty of this model arises from density-limited diffusion terms, which can lead to degeneracy in the parabolic equations. We find that the method established in Li et al. (J Differ Equ 371:353–395, 2023) works well to overcome the degenerate problem. This method combines the Lyapunov functionals and upper/lower solutions, and it can be applied to a broader range of reaction-diffusion systems even if the diffusion terms degenerate and have very poor properties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Global stability for age-infection-structured human immunodeficiency virus model with heterogeneous transmission.
- Author
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Juping Zhang, Linlin Wang, and Zhen Jin
- Subjects
HIV ,EQUILIBRIUM ,EPIDEMIOLOGY ,RANK correlation (Statistics) ,SENSITIVITY analysis - Abstract
In this paper, we analyze the global asymptotic behaviors of a mathematical susceptibleinfected(SI) age-infection-structured human immunodeficiency virus(HIV) model with heterogeneous transmission. Mathematical analysis shows that the local and global dynamics are completely determined by the basic reproductive number R
0 . If R0 < 1, disease-free equilibrium is globally asymptotically stable. If R0 >1, it shows that diseasefree equilibrium is unstable and the unique endemic equilibrium is globally asymptotically stable. The proofs of global stability utilize Lyapunov functions. Besides, the numerical simulations are illustrated to support these theoretical results and sensitivity analysis of each parameter for R0 is performed by the method of partial rank correlation coefficient(PRCC). [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
23. Periodic dynamics of a single species model with seasonal Michaelis-Menten type harvesting, II: Existence of two periodic solutions.
- Author
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Liu, Yunfeng, Feng, Xiaomei, Ruan, Shigui, and Yu, Jianshe
- Subjects
- *
LOTKA-Volterra equations , *SEASONS , *BIOLOGICAL extinction , *DIFFERENTIAL equations , *SPECIES , *COMPUTER simulation - Abstract
In a previous paper (Feng et al., J. Differential Equations (2023)), we studied a seasonally interactive model between closed seasons and open seasons with Michaelis-Menten type harvesting, in which we assumed that the harvesting quantity was relatively large (0 < κ = l G c E < 1) and obtained a length threshold of the closed season T ¯ ⁎ depending on the harvesting parameter and the seasonal fluctuation period. It was shown that the origin is globally asymptotically stable if and only if T ¯ ≤ T ¯ ⁎ , and there exists a unique globally asymptotically stable T -periodic solution if and only if T ¯ > T ¯ ⁎. In this paper, we continue to investigate the periodic dynamics of this model when the harvesting quantity is relatively small (κ = l G c E ≥ 1). By finding another smaller length threshold T ¯ ⁎ ∈ (0 , T ¯ ⁎) , we determine the number of periodic solutions and study their stability, which imply the occurrence of bifurcation of periodic solutions. Our results demonstrate that designing the closed harvesting season properly can prevent the species from extinction. Moreover, by comparing with the continuous harvesting model and combining the results in our previous paper and this article, we provide a complete understanding on the global dynamics for the periodic switching model. Some numerical simulations are also carried out to illustrate the theoretical results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Global Behavior of Solutions to a Higher-Dimensional System of Difference Equations with Lucas Numbers Coefficients.
- Author
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Berkal, Messaoud, Navarro, Juan Francisco, and Abo-Zeid, Raafat
- Subjects
FIBONACCI sequence ,LUCAS numbers ,DIFFERENCE equations - Abstract
In this paper, we derive the well-defined solutions to a θ -dimensional system of difference equations. We show that, the well-defined solutions to that system are represented in terms of Fibonacci and Lucas sequences. Moreover, we study the global stability of the solutions to that system. Finally, we give some numerical examples which confirm our theoretical results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Open Problems and Conjectures in the Evolutionary Periodic Ricker Competition Model.
- Author
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Luís, Rafael
- Subjects
GLOBAL asymptotic stability ,LOGICAL prediction - Abstract
In this paper, we present a survey about the latest results in global stability concerning the discrete-time evolutionary Ricker competition model with n species, in both, autonomous and periodic models. The main purpose is to convey some arguments and new ideas concerning the techniques for showing global asymptotic stability of fixed points or periodic cycles in these kind of discrete-time models. In order to achieve this, some open problems and conjectures related to the evolutionary Ricker competition model are presented, which may be a starting point to study global stability, not only in other competition models, but in predator–prey models and Leslie–Gower-type models as well. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Threshold Dynamics of an SEIS Epidemic Model with Nonlinear Incidence Rates.
- Author
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Naim, Mouhcine, Lahmidi, Fouad, and Namir, Abdelwahed
- Abstract
In this paper, we consider an SEIS epidemic model with infectious force in latent and infected period, which incorporates by nonlinear incidence rates. The local stability of the equilibria is discussed. By means of Lyapunov functionals and LaSalle's invariance principle, we proved the global asymptotic stability of the disease-free equilibrium and the endemic equilibrium. An application is given and numerical simulation results based on real data of COVID-19 in Morocco are performed to justify theoretical findings. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. BIFURCATION ANALYSIS OF AN ALLELOPATHIC PHYTOPLANKTON MODEL.
- Author
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CHEN, SHANGMING, CHEN, FENGDE, LI, ZHONG, and CHEN, LIJUAN
- Subjects
PHYTOPLANKTON ,POSITIVE systems ,COMPUTER simulation - Abstract
This paper analyzes an allelopathic phytoplankton competition model, which was proposed by Bandyopadhyay [Dynamical analysis of a allelopathic phytoplankton model, J Biol Syst14(02):205–217, 2006]. Our study refines the previous results and finds at most three positive equilibria for the system. The existence conditions of all positive equilibria and the corresponding stability cases are given in the paper. Interesting dynamical phenomena such as bistability, saddle-node bifurcation, and cusp bifurcation are found. It is shown that the rate of toxin releases heavily influences the positive equilibria of the system under certain conditions. Numerical simulations verify the feasibility of the theoretical results. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. Global stability of bistable traveling wavefronts for a three-species Lotka–Volterra competition system with nonlocal dispersal.
- Author
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Hao, Yu-Cai and Zhang, Guo-Bao
- Subjects
LOTKA-Volterra equations ,DYNAMICAL systems - Abstract
This paper is devoted to the study of traveling wavefronts for a three-component Lotka–Volterra system with nonlocal dispersal. This system arises in the study of three-species competition model in which there is no competition between two of these three species. It has been shown that this system admits a bistable traveling wavefront. In this paper, we further investigate the stability of bistable traveling wavefronts. By constructing suitable super- and sub-solutions and using a dynamical system approach, we obtain the globally asymptotic stability of the bistable traveling wavefronts. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Almost periodic solutions of fuzzy shunting inhibitory CNNs with delays.
- Author
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Kashkynbayev, Ardak, Koptileuova, Moldir, Issakhanov, Alfarabi, and Cao, Jinde
- Subjects
COMPUTER simulation ,ARTIFICIAL neural networks ,DIFFERENTIAL equations ,FUZZY logic ,EXPONENTIAL stability - Abstract
In the present paper, we prove the existence of unique almost periodic solutions to fuzzy shunting inhibitory cellular neural networks (FSICNN) with several delays. Further, by means of Halanay inequality we analyze the global exponential stability of these solutions and obtain corresponding convergence rate. The results of this paper are new, and they are concluded with numerical simulations confirming them. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
30. Dynamical analysis of a general delayed HBV infection model with capsids and adaptive immune response in presence of exposed infected hepatocytes
- Author
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Foko, Severin
- Published
- 2024
- Full Text
- View/download PDF
31. Global stability and optimal vaccination control of SVIR models.
- Author
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Xinjie Zhu, Hua Liu, Xiaofen Lin, Qibin Zhang, and Yumei Wei
- Subjects
BASIC reproduction number ,INFECTIOUS disease transmission ,VACCINE effectiveness ,VACCINATION ,HOPF bifurcations ,COMMUNICABLE diseases - Abstract
Vaccination is widely acknowledged as an affordable and cost-effective approach to guard against infectious diseases. It is important to take vaccination rate, vaccine effectiveness, and vaccine-induced immune decline into account in epidemic dynamical modeling. In this paper, an epidemic dynamical model of vaccination is developed. This model provides a framework of the infectious disease transmission dynamics model through qualitative and quantitative analysis. The result shows that the system may have multiple equilibria. We used the next-generation operator approach to calculate the maximum spectral radius, that is, basic reproduction number R
vac . Next, by dividing the model into infected and uninfected subjects, we can prove that the disease-free equilibrium is globally asymptotically stable when Rvac < 1, provided certain assumptions are satisfied. When Rvac > 1, there exists a unique endemic equilibrium. Using geometric methods, we calculate the second compound matrix and demonstrate the Lozinskii measure ... ≤ 0, which is equivalent to the unique endemic equilibrium, which is globally asymptotically stable. Then, using center manifold theory, we justify the existence of forward bifurcation. As the vaccination rate decreases, the likelihood of forward bifurcation increases. We also theoretically show the presence of Hopf bifurcation. Then, we performed sensitivity analysis and found that increasing the vaccine effectiveness rate can curb the propagation of disease effectively. To examine the influence of vaccination on disease control, we chose the vaccination rate as the optimal vaccination control parameter, using the Pontryagin maximum principle, and we found that increasing vaccination rates reduces the number of infected individuals. Finally, we ran a numerical simulation to finalize the theoretical results. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
32. Global Asymptotic Stability and Asymptotically Periodic Oscillation in Fractional-Order Fuzzy Cohen-Grossberg Neural Networks with Delays.
- Author
-
Shaobin Rao and Tianwei Zhang
- Subjects
- *
GLOBAL asymptotic stability , *FUZZY neural networks , *OSCILLATIONS - Abstract
This paper focuses on the S-asymptotically Periodic oscillation for a type of fractional-order fuzzy Cohen-Grossberg neural networks (CGNNs) by employing some properties of Mittag-Leffler mappings and fixed point theorems. Further, the global asymptotic stability of CGNNs is received. For CGNNs, our works in this paper not only enrich its theoretical achievements, but also expand its application scope. [ABSTRACT FROM AUTHOR]
- Published
- 2024
33. DYNAMICAL ANALYSIS OF A COVID-19 MODEL WITH HUMAN-TO-HUMAN AND ENVIRONMENT-TO-HUMAN TRANSMISSIONS AND DISTRIBUTED DELAYS.
- Author
-
JIE XU, YAYUAN LEI, ABDULLAH, TARIQ Q. S., and GANG HUANG
- Subjects
COVID-19 ,INFECTIOUS disease transmission ,HUMAN-to-human transmission ,VIRAL transmission ,COMPUTER simulation - Abstract
ARS-CoV-2 can survive in different environments and remain infectious for several days, which presents challenges to eliminating infectious diseases. It encourages researchers to study the effects of SARS-CoV-2 on the environment. In this paper, we formulate an epidemic model for SARS-CoV-2, which focuses on the transmission of the virus under environmental conditions. Two distributed delays are introduced to describe the probability of the exposed and infected individuals in different infection periods based on the transmission of the virus in the environment. The positivity and boundness of solutions of model are derived. The basic reproduction number threshold theory is established and the results demonstrate that the persistence of COVID-19 depends on the basic reproduction number. Numerical simulations are presented to verify the theoretical results. Some measures are proposed to control and eliminate COVID-19 infectious diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. The global stability and optimal control of the COVID-19 epidemic model.
- Author
-
Chien, Fengsheng, Nik, Hassan Saberi, Shirazian, Mohammad, and Gómez-Aguilar, J. F.
- Subjects
COVID-19 pandemic ,LYAPUNOV functions ,EPIDEMICS ,INFECTIOUS disease transmission ,DYNAMICAL systems ,PREVENTIVE medicine ,EQUILIBRIUM - Abstract
This paper considers stability analysis of a Susceptible-Exposed-Infected-Recovered-Virus (SEIRV) model with nonlinear incidence rates and indicates the severity and weakness of control factors for disease transmission. The Lyapunov function using Volterra–Lyapunov matrices makes it possible to study the global stability of the endemic equilibrium point. An optimal control strategy is proposed to prevent the spread of coronavirus, in addition to governmental intervention. The objective is to minimize together with the quantity of infected and exposed individuals while minimizing the total costs of treatment. A numerical study of the model is also carried out to investigate the analytical results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Nonlinear optimal control for free-floating space robotic manipulators.
- Author
-
Rigatos, G., Pomares, J., Abbaszadeh, M., Busawon, K., Gao, Z., and Zouari, F.
- Subjects
ROBOTS ,SPACE vehicles ,RICCATI equation ,NONLINEAR dynamical systems ,JACOBIAN matrices - Abstract
Free-floating space robotic manipulators (FSRMs) are robotic arms mounted on space platforms, such as spacecraft or satellites which are used for the repair of space vehicles or the removal of noncooperating targets such as inactive material remaining in orbit. In this paper, a novel nonlinear optimal control method is applied to the dynamic model of FSRMs. First, the state-space model of a 3-DOF free-floating space robot is formulated and its differential flatness properties are proven. This model undergoes approximate linearization around a temporary operating point that is recomputed at each time-step of the control method. The linearization relies on Taylor series expansion and on the associated Jacobian matrices. For the linearized state-space model of the free-floating space robot a stabilizing optimal (H-infinity) feedback controller is designed. This controller stands for the solution of the nonlinear optimal control problem under model uncertainty and external perturbations. To compute the controller's feedback gains an algebraic Riccati equation is repetitively solved at each iteration of the control algorithm. The stability properties of the control method are proven through Lyapunov analysis. The proposed nonlinear optimal control approach achieves fast and accurate tracking of setpoints under moderate variations of the control inputs and a minimum dispersion of energy by the actuators of the free-floating space robot. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. STUDY OF INTEGER AND FRACTIONAL ORDER COVID-19 MATHEMATICAL MODEL.
- Author
-
OUNCHAROEN, RUJIRA, SHAH, KAMAL, UD DIN, RAHIM, ABDELJAWAD, THABET, AHMADIAN, ALI, SALAHSHOUR, SOHEIL, and SITTHIWIRATTHAM, THANIN
- Subjects
MATHEMATICAL models ,LYAPUNOV functions ,COVID-19 ,JACOBIAN matrices ,INFECTIOUS disease transmission ,MATRIX functions - Abstract
In this paper, we study a nonlinear mathematical model which addresses the transmission dynamics of COVID-19. The considered model consists of susceptible (S), exposed (E), infected (I), and recovered (R) individuals. For simplicity, the model is abbreviated as S E I R. Immigration rates of two kinds are involved in susceptible and infected individuals. First of all, the model is formulated. Then via classical analysis, we investigate its local and global stability by using the Jacobian matrix and Lyapunov function method. Further, the fundamental reproduction number ℛ 0 is computed for the said model. Then, we simulate the model through the Runge–Kutta method of order two abbreviated as RK2. Finally, we switch over to the fractional order model and investigate its numerical simulations corresponding to different fractional orders by using the fractional order version of the aforementioned numerical method. Finally, graphical presentations are given for the approximate solution of various compartments of the proposed model. Also, a comparison with real data has been shown. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Dynamics in two-predator and one-prey models with signal-dependent motility.
- Author
-
Zhang, Duo and Hu, Xuegang
- Subjects
GLOBAL asymptotic stability ,NEUMANN boundary conditions ,LOTKA-Volterra equations - Abstract
This paper deals with the global boundedness and asymptotic stability of the solution of the two-predator and one-prey systems with density-dependent motion in a n-dimensional bounded domain with Neumann boundary conditions. In a previous paper, Qiu et al. (J Dyn Differ Equ, 1–25, 2021) proved the global existence and uniform boundedness of classical solution by limiting the conditions on motility functions and the coefficients of logistic source. By contrast, we relax the limitation conditions in Qiu et al. (2021) by constructing the weight function. Moreover, under diverse competition circumstances, the global stabilities of nonnegative spatially homogeneous equilibria for the special model are established. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Global dynamics of a time-fractional spatio-temporal SIR model with a generalized incidence rate
- Author
-
Bouissa, Ayoub, Tahiri, Mostafa, Tsouli, Najib, and Sidi Ammi, Moulay Rchid
- Published
- 2023
- Full Text
- View/download PDF
39. Analytical solution of the fractional and global stability of multicompartment non-linear epidemic model.
- Author
-
Chahrazed, LAID
- Subjects
ANALYTICAL solutions ,GLOBAL analysis (Mathematics) ,DECOMPOSITION method ,EPIDEMIOLOGICAL models ,EQUILIBRIUM ,LYAPUNOV functions - Abstract
In this paper the Multicompartment epidemiological model assumes that. given a contagious illness. a population can be partitioned into individuals that are susceptible to the illness. infected by the illness, and recovered from the illness.S(t) Number of individuals at time t susceptible to the illness;/(thi= 1.2.3.4 Number of individuals at time t infected with the illness.R
s (t) Total number of survivors of the illness at time t. RD (t) Total number of deaths due to the illness at time t. The stability of a disease-free status equilibrium and the existence of endemic equilibrium can be determined by the ratio called the basic reproductive number. Laplace-adomian decomposition method is used to compute an analytical solution of the model study. This paper study the equilibrium. local. global stability under certain conditions. [ABSTRACT FROM AUTHOR]- Published
- 2022
40. Mathematical analysis of a Candida auris nosocomial infection model on the effects of misidentification in infection transmission.
- Author
-
Lavanya, R. and Shyni, U. K.
- Subjects
NOSOCOMIAL infections ,MATHEMATICAL analysis ,INFECTIOUS disease transmission ,CANDIDA ,INTENSIVE care units - Abstract
The aim of this research paper is to model the effects of misidentification in the transmission dynamics of the super yeast, Candida auris (or C. auris), among patients receiving treatment in the Intensive Care Units (ICUs). The mathematical analysis is carried out by obtaining the reproduction number of the C. auris model using the next generation matrix and utilizing it as a threshold value to establish the local and global stability properties at the points of equilibria. The numerical investigations carried out in this paper establish the outcomes of the effect of variations in the values of important parameters on the dynamics of C. auris colonization and infections in the health care settings. The corresponding results from the numerical simulations are illustrated graphically. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. On PID Control Theory for Nonaffine Uncertain Stochastic Systems.
- Author
-
Zhang, Jinke, Zhao, Cheng, and Guo, Lei
- Abstract
PID (proportional-integral-derivative) control is recognized to be the most widely and successfully employed control strategy by far. However, there are limited theoretical investigations explaining the rationale why PID can work so well when dealing with nonlinear uncertain systems. This paper continues the previous researches towards establishing a theoretical foundation of PID control, by studying the regulation problem of PID control for nonaffine uncertain nonlinear stochastic systems. To be specific, a three dimensional parameter set will be constructed explicitly based on some prior knowledge on bounds of partial derivatives of both the drift and diffusion terms. It will be shown that the closed-loop control system will achieve exponential stability in the mean square sense under PID control, whenever the controller parameters are chosen from the constructed parameter set. Moreover, similar results can also be obtained for PD (PI) control in some special cases. A numerical example will be provided to illustrate the theoretical results. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
42. A predator-prey model for the optimal control of fish harvesting through the imposition of a tax.
- Author
-
Chatterjee, Anal and Pal, Samares
- Subjects
PREDATION ,FISHERY management ,HARVESTING ,PONTRYAGIN'S minimum principle ,HOPF bifurcations ,EQUATIONS of state - Abstract
This paper is devoted to the study of ecosystem based fisheries management. The model represents the interaction between prey and predator population with Holling II functional response consisting of different carrying capacities and constant intrinsic growth rates. We have considered the continuous harvesting of predator only. It is observed that if the intrinsic growth rate of predator population crosses a certain critical value, the system enters into Hopf bifurcation. Our observations indicate that tax, the management object in fisheries system play huge impacts on this system. The optimal harvesting policy is disposed by imposing a tax per unit of predator biomass. The optimal harvest strategy is determined using Pontryagin's maximum principle, which is subject to state equations and control limitations. The implications of tax are also examined. We have derived different bifurcations and global stability of the system. Finally, numerical simulations are used to back up the analytical results. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
43. Dynamics of an \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${ SVEIRS}$$\end{document}SVEIRS Epidemic Model with Vaccination and Saturated Incidence Rate
- Author
-
Kunwer Singh, Mathur and Prakash, Narayan
- Subjects
Original Paper ,Reproduction number ,Pre and post vaccinations ,Saturated incidence rate ,Global stability - Abstract
Measles and influenza are two major diseases–caused an epidemic in India. Therefore, in this paper, a \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${ SVEIRS}$$\end{document}SVEIRS epidemic mathematical model for measles and influenza is proposed and analyzed, where pre and post vaccinations are considered as control strategies with waning natural, vaccine-induced immunity and saturation incidence rate. The dissection of the proposed model is conferred in terms of the associated reproduction number \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathcal {R}}_v$$\end{document}Rv, which is determined by the next-generation approach and obtained that if \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathcal {R}}_v\le 1$$\end{document}Rv≤1, the disease-free equilibrium exists and it is locally as well as globally asymptotically stable. Further for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathcal {R}}_v> 1$$\end{document}Rv>1, a unique endemic equilibrium exists and it is also locally as well as globally asymptotically stable under certain conditions, which shows the prevalence and persistence of the disease in the population.
- Published
- 2018
44. Dynamic Behavior of a Class of Delayed Lotka–Volterra Recurrent Neural Networks on Time Scales.
- Author
-
Es-saiydy, M. and Zitane, M.
- Abstract
In this paper, Lotka–Volterra recurrent neural networks with time-varying delays on time scales are considered. Using Banach's fixed-point principle, the theory of calculus on time scales and suitable Lyapunov functional, some sufficient conditions for the existence, uniqueness and Stepanov-exponential stability of positive weighted Stepanov-like pseudo almost periodic solution on time scales to the recurrent neural networks are established. Finally, an illustrative example and simulations are presented to demonstrate the effectiveness of the theoretical findings of the paper. The results of this paper are new and generalize some previously-reported results in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
45. Modelling and analysis of periodic impulsive releases of the Nilaparvata lugens infected with wStri-Wolbachia.
- Author
-
Dai, Xiangjun, Quan, Qi, and Jiao, Jianjun
- Subjects
NILAPARVATA lugens ,NUMERICAL analysis - Abstract
In this paper, we formulate a population suppression model and a population replacement model with periodic impulsive releases of Nilaparvata lugens infected with wStri. The conditions for the stability of wild- $ N.\,lugens $ N. l u g e n s -eradication periodic solution of two systems are obtained by applying the Floquet theorem and comparison theorem. And the sufficient conditions for the persistence in the mean of wild $ N.\,lugens $ N. l u g e n s are also given. In addition, the sufficient conditions for the extinction and persistence of the wild $ N.\,lugens $ N. l u g e n s in the subsystem without wLug are also obtained. Finally, we give numerical analysis which shows that increasing the release amount or decreasing the release period are beneficial for controlling the wild $ N.\,lugens $ N. l u g e n s , and the efficiency of population replacement strategy in controlling wild populations is higher than that of population suppression strategy under the same release conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
46. On the control and analysis of a mathematical model Covid-19 with bats and human compartments.
- Author
-
Karim, Marouane, Lafif, Marouane, Khaloufi, Issam, and Rachik, Mostafa
- Subjects
BATS ,MATHEMATICAL analysis ,MATHEMATICAL models ,COVID-19 ,INFECTIOUS disease transmission - Abstract
In this paper. we propose a mathematical model that describes the dynamics of transmission of COVID-19 between potential people and infected ones, as well as between bats as virus carriers and people. This article deals with optimal control applied to vaccination, treatment strategies, and the hunt for a SIR-B epidemic model with logistic growth. The global stability of the disease-free and endemic equilibrium is verified. The existence of optimal control is demonstrated. The Pontryagin maximum principle is employed to describe these optimal controls. To validate our previous theoretical results. the optimality system is numerically resolved using a Matlab algorithm based on the Runge Kutta approximation 4. [ABSTRACT FROM AUTHOR]
- Published
- 2023
47. Global Properties of Cytokine-Enhanced HIV-1 Dynamics Model with Adaptive Immunity and Distributed Delays.
- Author
-
Dahy, Elsayed, Elaiw, Ahmed M., Raezah, Aeshah A., Zidan, Hamdy Z., and Abdellatif, Abd Elsattar A.
- Subjects
HIGHLY active antiretroviral therapy ,HOPFIELD networks ,CYTOTOXIC T cells ,HIV ,GLOBAL asymptotic stability ,ADAPTIVE control systems ,BASIC reproduction number - Abstract
In this paper, we study a model that enhances our understanding of cytokine-influenced HIV-1 infection. The impact of adaptive immune response (cytotoxic T lymphocytes (CTLs) and antibodies) and time delay on HIV-1 infection is included. The model takes into account two types of distributional delays, (i) the delay in the HIV-1 infection of CD4
+ T cells and (ii) the maturation delay of new virions. We first investigated the fundamental characteristics of the system, then found the system's equilibria. We derived five threshold parameters, ℜ i , i = 0, 1,..., 4, which completely determine the existence and stability of the equilibria. The Lyapunov method was used to prove the global asymptotic stability for all equilibria. We illustrate the theoretical results by performing numerical simulations. We also performed a sensitivity analysis on the basic reproduction number ℜ 0 and identified the most-sensitive parameters. We found that pyroptosis contributes to the number ℜ 0 , and then, neglecting it will make ℜ 0 underevaluated. Necrosulfonamide and highly active antiretroviral drug therapy (HAART) can be effective in preventing pyroptosis and at reducing viral replication. Further, it was also found that increasing time delays can effectively decrease ℜ 0 and, then, inhibit HIV-1 replication. Furthermore, it is shown that both CTLs and antibody immune responses have no effect on ℜ 0 , while this can result in less HIV-1 infection. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
48. Global stability of a PDE-ODE model for acid-mediated tumor invasion.
- Author
-
Li, Fang, Yao, Zheng-an, and Yu, Ruijia
- Subjects
- *
CANCER invasiveness , *TUMORS , *FUNCTIONALS - Abstract
In this paper, we study the global dynamics of a general reaction-diffusion model based on acid-mediated invasion hypothesis, which is a candidate explanation for the Warburg effect. Our theoretical results characterize the effects of acid resistance and mutual competition of healthy cells and tumor cells on tumor progression in the long term, i.e., whether the healthy cells and tumor cells coexist or the tumor cells prevail after tumor invasion. A key feature of this model is the density-limited tumor diffusion term for tumor cells, which might give rise to the degeneracy of the parabolic equation. To overcome this difficulty, we combine the construction of suitable Lyapunov functionals and upper/lower solutions. This paper continues and improves the work begun in [15]. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. Ultimate Dynamics of the Two-Phenotype Cancer Model: Attracting Sets and Global Cancer Eradication Conditions.
- Author
-
Kanatnikov, Anatolij N. and Starkov, Konstantin E.
- Subjects
POLYTOPES ,IMMUNE response ,COMPUTER simulation ,INVARIANT sets - Abstract
In this paper we consider the ultimate dynamics of one 4D cancer model which was created for studying the immune response to the two-phenotype tumors. Our approach is based on the localization method of compact invariant sets. The existence of a positively invariant polytope is shown and its size is calculated depending on the parameters of this cancer model. Various convergence conditions to the tumor free equilibrium point were proposed. This property has the biological meaning of global asymptotic tumor eradication (GATE). Further, the case in which local asymptotic tumor eradication (LATE) conditions entail GATE conditions was found. Our theoretical studies of ultimate dynamics are complemented by numerical simulation results. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
50. Effects of additional food availability and pulse control on the dynamics of a Holling-($ p $+1) type pest-natural enemy model.
- Author
-
Yan, Xinrui, Tian, Yuan, and Sun, Kaibiao
- Subjects
INTEGRATED pest control ,COMPUTER simulation ,POPULATION dynamics ,STABILITY theory - Abstract
In this paper, a novel pest-natural enemy model with additional food source and Holling-( p +1) type functional response is put forward for plant pest management by considering multiple food sources for predators. The dynamical properties of the model are investigated, including existence and local asymptotic stability of equilibria, as well as the existence of limit cycles. The inhibition of natural enemy on pest dispersal and the impact of additional food sources on system dynamics are elucidated. In view of the fact that the inhibitory effect of the natural enemy on pest dispersal is slow and in general deviated from the expected target, an integrated pest management model is established by regularly releasing natural enemies and spraying insecticide to improve the control effect. The influence of the control period on the global stability and system persistence of the pest extinction periodic solution is discussed. It is shown that there exists a time threshold, and as long as the control period does not exceed that threshold, pests can be completely eliminated. When the control period exceeds that threshold, the system can bifurcate the supercritical coexistence periodic solution from the pest extinction one. To illustrate the main results and verify the effectiveness of the control method, numerical simulations are implemented in MATLAB programs. This study not only enriched the related content of population dynamics, but also provided certain reference for the management of plant pest. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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