Sajad Jafari

11 Questions 27 Answers 0 Followers

Questions related from Sajad Jafari

How we engineers and mathematicians can be of help in fighting COVOD-19?

While most governments try to hide the facts and manipulate statistics about COVOD-19 due to political/economical/stupidity reasons, many physicians and scientists are currently working on finding...

04 March 2020 5,307 26 View

Can anybody help us with obtaining a code to calculate “Master Stability Function”?

We are working on some projects related to networks of coupled nonlinear oscillators. We want to obtain “Master Stability Function” (MSF) in our network. 1. Is there any sample code available in...

30 September 2018 9,471 3 View

Is that possible to calculate Largest Lyapunov Exponent in a 2D chaotic map, without its equations, having only time series of one state?

Consider a 2D (or a higher dimension) chaotic map like Tinkerbell map: x(n+1) = x(n)2 -y(n)2 +a x(n) +b y(n) y(n+1) = 2x(n)y(n) +c x(n) +d y(n) Suppose that we don’t know the above equations and...

26 March 2016 7,661 3 View

Which important points should be considered in plotting a bifurcation diagram?

When we want to plot a bifurcation diagram for a flow or map, we should consider some important points. Some of them have been mentioned in [1]. For example we should be careful about coexisting...

31 December 2014 7,757 9 View

Is there any 2D system (flow) with more than one limit cycle?

Consider a general 2D system: x' = f(x,y) y’ = g(x,y) Do you know any such system (preferably a simple one, ideally quadratic) which has more than one limit cycle? I would prefer it if there was...

19 September 2013 5,576 9 View

Which one of the following systems is a bounded chaotic system?

I am dealing with some 3-D flows which I suspect are chaotic. Can someone investigate the following three systems and tell me if they are really chaotic (and bounded, not chaotic in transient and...

13 September 2013 8,973 19 View

What is the cause of chaos in a dynamical system?

Consider the famous Lorenz system: x' = 10(y-x) y’ = x(R-z)-y z’ = xy-8/3*z What is in there when R = 28, which is not in there when R = 26? I want an answer which will not be related to...

25 August 2013 1,785 13 View

How can we say for sure that a 4-D ODE is really 4-D and cannot be reduced to 3-D?

We know that some apparently "4-D systems" are just 3-D systems "lifted" into a higher dimension. For example, take the simplest chaotic jerk system: x' = y y' = z z' = -az + y^2 – x Let w = z' =...

17 June 2013 8,961 27 View

What is the best method to investigate the existence of chaos in a 3D conservative continues system (flow)?

I have some 3D conservative systems. They have positive largest Lyapunov exponent. It means they are chaotic. However there can be some problems: 1. Numerical errors in calculating Lyapunov...

16 May 2013 3,989 15 View

Does a 3-D chaotic system (flow) with only a curve equilibria or with only a surface equilibria exist? Is that possible?

I mean a 3D chaotic continuous system in which any point on a specific curve (or a surface) is equilibrium and no other equilibrium exists beside that. Any idea about characteristics of such systems?

10 May 2013 7,258 8 View

Can a strange attractor have a 2-D projection in the form of limit cycle?

Consider a chaotic system (flow, not map) which is described by: x1' = f1(x1, x2, xn) x2' = f2(x1, x2, xn) ….. xn' = fn(x1, x2, xn) Suppose that we project the strange attractor of this system...

02 May 2013 4,470 14 View