An interval polynomial theory approach to fixed-point bifurcation analysis in biological models

2014 ◽  
Author(s):  
Gerasimos G. Rigatos
Keyword(s):  
Fixed Point ◽  
Bifurcation Analysis ◽  
Theory Approach ◽  
Biological Models ◽  
Interval Polynomial ◽  
Polynomial Theory

scholarly journals Critical bifurcation surfaces of 3D discrete dynamics

2000 ◽  
Vol 4 (4) ◽  
pp. 333-343 ◽  
Author(s):  
Michael Sonis
Keyword(s):  
Fixed Point ◽  
Asymptotic Stability ◽  
Bifurcation Analysis ◽  
Analytical Representation ◽  
General Algorithm ◽  
Cournot Oligopoly ◽  
Adjustment Process ◽  
Discrete Dynamics ◽  
Oligopoly Model ◽  
Analytical Construction

This paper deals with the analytical representation of bifurcations of each 3D discrete dynamics depending on the set of bifurcation parameters. The procedure of bifurcation analysis proposed in this paper represents the 3D elaboration and specification of the general algorithm of then-dimensional linear bifurcation analysis proposed by the author earlier. It is proven that 3D domain of asymptotic stability (attraction) of the fixed point for a given 3D discrete dynamics is bounded by three critical bifurcation surfaces: the divergence, flip and flutter surfaces. The analytical construction of these surfaces is achieved with the help of classical Routh–Hurvitz conditions of asymptotic stability. As an application the adjustment process proposed by T. Puu for the Cournot oligopoly model is considered in detail.

scholarly journals Bifurcation Analysis of Piecewise Smooth Bimodal Maps Using Normal Form

2020 ◽  
Vol 24 (3) ◽  
pp. 137-151
Author(s):  
Z. T. Zhusubaliyev ◽  
D. S. Kuzmina ◽  
O. O. Yanochkina
Keyword(s):  
Fixed Point ◽  
Normal Form ◽  
Bifurcation Analysis ◽  
Stability Region ◽  
Piecewise Linear ◽  
Period Doubling ◽  
Piecewise Smooth ◽  
Continuous Map ◽  
The Stability ◽  
Smooth Map

Purpose of reseach. Studyof bifurcations in piecewise-smooth bimodal maps using a piecewise-linear continuous map as a normal form. Methods. We propose a technique for determining the parameters of a normal form based on the linearization of a piecewise-smooth map in a neighborhood of a critical fixed point. Results. The stability region of a fixed point is constructed numerically and analytically on the parameter plane. It is shown that this region is limited by two bifurcation curves: the lines of the classical period-doubling bifurcation and the “border collision” bifurcation. It is proposed a method for determining the parameters of a normal form as a function of the parameters of a piecewise smooth map. The analysis of "border-collision" bifurcations using piecewise-linear normal form is carried out. Conclusion. A bifurcation analysis of a piecewise-smooth irreversible bimodal map of the class Z1–Z3–Z1 modeling the dynamics of a pulse–modulated control system is carried out. It is proposed a technique for calculating the parameters of a piecewise linear continuous map used as a normal form. The main bifurcation transitions are calculated when leaving the stability region, both using the initial map and a piecewise linear normal form. The topological equivalence of these maps is numerically proved, indicating the reliability of the results of calculating the parameters of the normal form.

scholarly journals Stochastic Bifurcation Analysis of an Elastically Mounted Flapping Airfoil

2018 ◽  
Vol 148 ◽  
pp. 08001
Author(s):  
Chandan Bose ◽  
Sunetra Sarkar ◽  
Sayan Gupta
Keyword(s):  
Fixed Point ◽  
Probability Density Function ◽  
Probability Density ◽  
Density Function ◽  
Bifurcation Analysis ◽  
Stochastic Bifurcation ◽  
Stable Limit ◽  
Mean Flow ◽  
Flow Fluctuations ◽  
Flapping Airfoil

The present paper investigates the effects of noisy flow fluctuations on the fluid-structure interaction (FSI) behaviour of a span-wise flexible wing modelled as a two degree-of-freedom elastically mounted flapping airfoil. In the sterile flow conditions, the system undergoes a Hopf bifurcation as the free-stream velocity exceeds a critical limit resulting in a stable limit-cycle oscillation (LCO) from a fixed point response. On the other hand, the qualitative dynamics changes from a stochastic fixed point to a random LCO through an intermittent state in the presence of irregular flow fluctuations. The probability density function depicts the most probable system state in the phase space. A phenomenological bifurcation (P-bifurcation) analysis based on the transition in the topology associated with the structure of the joint probability density function (pdf) of the response variables has been carried out. The joint pdf corresponding to the stochastic fixed point possesses a Dirac delta function like structure with a sharp single peak around zero. As the mean flow speed crosses the critical value, the joint pdf bifurcates to a crater-like structure indicating the occurrence of a P-bifurcation. The intermittent state is characterized by the co-existence of the unimodal as well as the crater like structure.

scholarly journals Stability and Hopf Bifurcation Analysis of an Epidemic Model with Time Delay

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yue Zhang ◽  
Xue Li ◽  
Xianghua Zhang ◽  
Guisheng Yin
Keyword(s):  
Fixed Point ◽  
Hopf Bifurcation ◽  
Time Delay ◽  
Normal Form ◽  
Bifurcation Analysis ◽  
Epidemic Model ◽  
Theoretic Analysis ◽  
Simulation Results ◽  
The Stability ◽  
Positive Fixed Point

Epidemic models are normally used to describe the spread of infectious diseases. In this paper, we will discuss an epidemic model with time delay. Firstly, the existence of the positive fixed point is proven; and then, the stability and Hopf bifurcation are investigated by analyzing the distribution of the roots of the associated characteristic equations. Thirdly, the theory of normal form and manifold is used to drive an explicit algorithm for determining the direction of Hopf bifurcation and the stability of the bifurcation periodic solutions. Finally, some simulation results are carried out to validate our theoretic analysis.

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