Marszalek Wieslaw, Walczak Maciej
Department of Computer Science, Opole University of Technology, 45-758 Opole, Poland.
Entropy (Basel). 2024 Sep 9;26(9):770. doi: 10.3390/e26090770.
We discuss 1D, 2D and 3D bifurcation diagrams of two nonlinear dynamical systems: an electric arc system having both chaotic and periodic steady-state responses and a cytosolic calcium system with both periodic/chaotic and constant steady-state outputs. The diagrams are mostly obtained by using the 0-1 test for chaos, but other types of diagrams are also mentioned; for example, typical 1D diagrams with local maxiumum values of oscillatory responses (periodic and chaotic), the entropy method and the largest Lyapunov exponent approach. Important features and properties of each of the three classes of diagrams with one, two and three varying parameters in the 1D, 2D and 3D cases, respectively, are presented and illustrated via certain diagrams of the values, -1≤K≤1, from the 0-1 test and the sample entropy values SaEn>0. The values close to 0 indicate periodic and quasi-periodic responses, while those close to 1 are for chaotic ones. The sample entropy 3D diagrams for an electric arc system are also provided to illustrate the variety of possible bifurcation diagrams available. We also provide a comparative study of the diagrams obtained using different methods with the goal of obtaining diagrams that appear similar (or close to each other) for the same dynamical system. Three examples of such comparisons are provided, each in the 1D, 2D and 3D cases. Additionally, this paper serves as a brief review of the many possible types of diagrams one can employ to identify and classify time-series obtained either as numerical solutions of models of nonlinear dynamical systems or recorded in a laboratory environment when a mathematical model is unknown. In the concluding section, we present a brief overview of the advantages and disadvantages of using the 1D, 2D and 3D diagrams. Several illustrative examples are included.
我们讨论了两个非线性动力系统的一维、二维和三维分岔图:一个具有混沌和周期性稳态响应的电弧系统,以及一个具有周期性/混沌和恒定稳态输出的胞质钙系统。这些分岔图大多是通过使用混沌的0-1检验获得的,但也提到了其他类型的图;例如,具有振荡响应(周期性和混沌)局部最大值的典型一维图、熵方法和最大Lyapunov指数方法。分别给出了一维、二维和三维情况下,在一个、两个和三个可变参数下这三类分岔图各自的重要特征和性质,并通过0-1检验中-1≤K≤1的某些K值图和样本熵值SaEn>0进行了说明。接近0的K值表示周期性和准周期性响应,而接近1的K值表示混沌响应。还提供了电弧系统的样本熵三维图,以说明可用的各种可能的分岔图。我们还对使用不同方法获得的分岔图进行了比较研究,目的是为同一动力系统获得看起来相似(或彼此接近)的分岔图。提供了三个这样的比较示例,分别在一维、二维和三维情况下。此外,本文简要回顾了可用于识别和分类时间序列的多种可能类型的图,这些时间序列要么是非线性动力系统模型的数值解,要么是在数学模型未知时在实验室环境中记录的。在结论部分,我们简要概述了使用一维、二维和三维分岔图的优缺点。文中包含了几个说明性示例。