Wissmann, Jan (2024)
Identification of Emerging Patterns in Complex Systems.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00026594
Ph.D. Thesis, Primary publication, Publisher's Version
Text
dissertation_wissmann_20240128.pdf Copyright Information: CC BY-SA 4.0 International - Creative Commons, Attribution ShareAlike. Download (7MB) |
Item Type: | Ph.D. Thesis | ||||
---|---|---|---|---|---|
Type of entry: | Primary publication | ||||
Title: | Identification of Emerging Patterns in Complex Systems | ||||
Language: | English | ||||
Referees: | Hamacher, Prof. Dr. Kay ; Liebchen, Prof. Dr. Benno | ||||
Date: | 2 February 2024 | ||||
Place of Publication: | Darmstadt | ||||
Collation: | 106 Seiten | ||||
Date of oral examination: | 30 October 2023 | ||||
DOI: | 10.26083/tuprints-00026594 | ||||
Abstract: | Synchronization describes the onset of a common rhythm between two linear or chaotic oscillators. Originally, the research was developed around the observation of regular oscillators. Later, similar effects were described for coupled chaotic systems. In early experiments, chaotic systems were limited to identical synchronization. However, it was found that more complex types of synchronization also develop for chaotic systems. Current research also continues to focus on identical synchronization. We assume that this is due to the easy accessibility of identical synchronization. In this paper, we present an alternative, information-theoretical approach to synchronization detection. Mutual information has been used as an indicator of synchronization in previous work. However, we can establish and prove an accessible, formal relationship between synchronization and mutual information. With this insight, we propose Synchronized Mutual Information (SMI) as a measure of synchronization. This measure represents the coherence of two trajectories in the range of 0 to 1. With complete knowledge of the phase space, the upper bound of this measure then corresponds to a synchronized system. In addition to this basic measure, we propose an efficient implementation for estimating the SMI. We test this implementation on a coupled Lorenz/Rössler system and compare it with the "Auxiliary System Method". We also use the SMI in systems with many coupled chaotic oscillators. To obtain an assessment of the overall system, we propose different aggregations of the SMI and test them on examples from the literature. In recent years, the focus of research has shifted from fully synchronized systems to partially synchronized systems. Effects such as interrupted synchronization, cluster synchronization, and chimera states are of particular importance. We can show that our measurement can also contribute to a more accessible research of these sys- tems. Unlike other tools, the SMI works without knowledge of the system dynamics and can also be used for analysis when the equations of motion are unknown. We can show that the results of the SMI are equivalent to the results of the Transversal Lyapunov Exponent, while the SMI has a much wider range of applications. Finally, by analyzing real-world applications, we demonstrate the applicability of SMI to real-world data. We analyze historical stock prices of companies listed in the Dow Jones and try to identify dependencies between companies using cluster analysis. We also apply the SMI to an in-vitro model of neurons. Observing neurons over a longer period of time, we determine how the degree of interconnection of neurons is reflected in their synchronization. |
||||
Alternative Abstract: |
|
||||
Status: | Publisher's Version | ||||
URN: | urn:nbn:de:tuda-tuprints-265947 | ||||
Classification DDC: | 500 Science and mathematics > 530 Physics | ||||
Divisions: | 05 Department of Physics > Institute for Condensed Matter Physics 05 Department of Physics > Institute for Condensed Matter Physics > Theory of complex systems |
||||
Date Deposited: | 02 Feb 2024 10:13 | ||||
Last Modified: | 05 Feb 2024 07:24 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/26594 | ||||
PPN: | 51522359X | ||||
Export: |
View Item |