Master's Thesis

Analysis of Logistic Maps

Final Thesis 3.42 MB Appendix 3.9 kB

Author of thesis: Ing. Joshua Owolabi Adeleke

Acad. year: 2021/2022

Supervisor: prof. Mgr. Pavel Řehák, Ph.D.

Reviewer: doc. Ing. Jiří Šremr, Ph.D.

Abstract:

A logistic map is related to a discrete logistic equation. Unlike its continuous counterpart, a logistic difference equation exhibits very complicated dynamics including chaotic
behavior. This work thus investigated the qualitative behavior of the logistic map by
employing some mathematical tools.
This dynamics was studied systematically, in such a way that its nature from the pure
form to the point when it got complicated to deal with were studied closely. Furthermore,
the concept of conjugacy was employed at the point when its analytic computation posed
to be complicated, with which its characteristics were further revealed.
Notable inferences were made, among which is the description of the chaotic behavior of
the logistic map as revealed by its conjugacy with the tent map.
Thus, in course of this study, other tool for investigating the chaotic behavior of the
logistic map was remarked, which is the symbolic dynamic, with which future study on
the logistic map can take up on.

Keywords:

Logistic differential equation, logistic difference equation, equilibrium point, stability, nperiodic cycle, Schwarzian derivative, bifurcation, period doubling, Lyapunov exponent, chaos, conjugacy, tent map, symbolic dynamics.

Date of defence

15.06.2022

Result of the defence

Defended (thesis was successfully defended)

znamkaBznamka

Grading

B

Process of defence

The student introduced his diploma thesis to the committee members and explained the fundamentals of his topic called Analysis of Logistic Maps. The supervisor read the review. The opponent read the review. His question was answered during presentation well. Prof. Šlapal asked about the model in biology - student answered satisfactorily.

Language of thesis

English

Faculty

Department

Study programme

Mathematical Engineering (N-MAI-A)

Composition of Committee

prof. RNDr. Josef Šlapal, CSc. (předseda)
doc. Ing. Luděk Nechvátal, Ph.D. (místopředseda)
doc. RNDr. Jiří Tomáš, Dr. (člen)
doc. Ing. Jiří Šremr, Ph.D. (člen)
prof. Mgr. Pavel Řehák, Ph.D. (člen)
prof. Bruno Rubino (člen)

Supervisor’s report
prof. Mgr. Pavel Řehák, Ph.D.

The thesis deals with analysis of a discrete logistic equation which in contrast to its continuous couterpart exhibits very complex dynamics. In particular, the following topics are treated within the study of the logistic map: stability of equilibria, periodic cycles and period-doubling, bifurcation, tent map, conjugacy, chaotic behavior, and Lyapunov exponents.

I really appreciate the student's independence in working on a difficult topic. He performed many analytic computations and also numerical simulations. Even in some parts which serve just as a description of supporting tools (and students here typically simply copy a relevant text from the literature), the author tried to bring his own contribution. English is very good.
As for the problematic points, in particular Chapter 4 should deserve some revision. Further, quotation of sources is not faultless. There are some typos and other imperfections. But they are mostly of minor character.

The author demonstrated the ability to work on an advanced topic and created an interesting text which offers quite many qualitative as well as quantitative aspects of logistic map.

The main goals have been achieved, and in view of the above said I can recommend the thesis for defense with overall classification B = very good.
Evaluation criteria Grade
Splnění požadavků a cílů zadání B
Postup a rozsah řešení, adekvátnost použitých metod B
Vlastní přínos a originalita B
Schopnost interpretovat dosažené výsledky a vyvozovat z nich závěry B
Využitelnost výsledků v praxi nebo teorii B
Logické uspořádání práce a formální náležitosti B
Grafická, stylistická úprava a pravopis C
Práce s literaturou včetně citací C
Samostatnost studenta při zpracování tématu A

Grade proposed by supervisor: B

Reviewer’s report
doc. Ing. Jiří Šremr, Ph.D.

The present thesis is focused to the analysis of the logistic equation, iterations in the real line, and chaotic dynamic.

I would like to appreciate:

1. The author composed a consistent and meaningful text concerning quite difficult topic.
2. The thesis has the logical structure, all discussed notions are illustrated by numerical simulations.
3. Namely, Section 3.1 concerning the periodic orbits of the logistic equation is written very well.

On the other hand, I have some objections, in particular:

1. Citations to the list of references are missing in the whole text. The author formulates lemmas and propositions without proofs and citations to the literature.
2. The text contains some mathematical inaccuracies which is, however, standard in such a type of students' works (e.g., discussion concerning the behaviour of iterates on p. 16, comparison of equations (2.4) and (2.5), arrows in figure 9, connection between the existence of a dense orbit and density of the set of periodic points).
3. Definitions of some notions are missing (e.g., basin of attraction for the orbit).

Conclusion: The author demonstrated the ability to work on a difficult topic, compose a meaningful text, and accomplish some numerical simulations. In my opinion, main goals of the thesis have been achieved. In view of the above-said, I can recommend the thesis for defense and I propose the evaluation B.
Evaluation criteria Grade
Splnění požadavků a cílů zadání A
Postup a rozsah řešení, adekvátnost použitých metod A
Vlastní přínos a originalita B
Schopnost interpretovat dosaž. výsledky a vyvozovat z nich závěry B
Využitelnost výsledků v praxi nebo teorii B
Logické uspořádání práce a formální náležitosti A
Grafická, stylistická úprava a pravopis A
Práce s literaturou včetně citací C
Topics for thesis defence:
  1. Why do you assume for further analysis on p. 25 that \mu\geq1?

Grade proposed by reviewer: B

Responsibility: Mgr. et Mgr. Hana Odstrčilová