Passive dynamic walking is a model that walks down a shallow slope without any control or input. This model has been widely used to investigate how humans walk with low energy consumption and provides design principles for energy-efficient biped robots. However, the basin of attraction is very small and thin and has a fractal-like complicated shape, which makes producing stable walking difficult. In our previous study, we used the simplest walking model and investigated the fractal-like basin of attraction based on dynamical systems theory by focusing on the hybrid dynamics of the model composed of the continuous dynamics with saddle hyperbolicity and the discontinuous dynamics caused by the impact upon foot contact. We clarified that the fractal-like basin of attraction is generated through iterative stretching and bending deformations of the domain of the Poincaré map by sequential inverse images. However, whether the fractal-like basin of attraction is actually fractal, i.e., whether infinitely many self-similar patterns are embedded in the basin of attraction, is dependent on the slope angle, and the mechanism remains unclear. In the present study, we improved our previous analysis in order to clarify this mechanism. In particular, we newly focused on the range of the Poincaré map and specified the regions that are stretched and bent by the sequential inverse images of the Poincaré map. Through the analysis of the specified regions, we clarified the conditions and mechanism required for the basin of attraction to be fractal.
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http://dx.doi.org/10.1088/1748-3190/ab9283 | DOI Listing |
Nat Commun
December 2024
Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich, CH-8057, Switzerland.
Transcription factor binding sites (TFBSs) are important sources of evolutionary innovations. Understanding how evolution navigates the sequence space of such sites can be achieved by mapping TFBS adaptive landscapes. In such a landscape, an individual location corresponds to a TFBS bound by a transcription factor.
View Article and Find Full Text PDFCogn Neurodyn
December 2024
Center for Research, SRM Institute of Science and Technology, Ramapuram, Chennai, 600089 India.
This study delves into the examination of a network of adaptive synapse neurons characterized by a small-world network topology connected through electromagnetic flux and infused with randomness. First, this research extensively explores the existence of the global multi-stability of a single adaptive synapse-based neuron model with magnetic flux. The non-autonomous neuron model exhibits periodically switchable equilibrium states that are strongly related to the transitions between stable and unstable points in every whole periodic cycle, leading to the creation of global multi-stability.
View Article and Find Full Text PDFChemosphere
December 2024
Shanxi Key Laboratory of Sorghum Genetic and Germplasm Innovation, Sorghum Research Institute, Shanxi Agricultural University, Jinzhong 030600, China.
Antibiotics in surface water have attracted increasing attention because of their potential threats to aquatic ecosystems and public health. Therefore, it is crucial to develop a priority antibiotic list and establish a regulatory framework for antibiotic control. Taking the Fenhe River Basin in North China as the study area, a method to rank priority antibiotics based on their environmental exposure, ecological effects, and human health risks was established.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Department of Applied Mechanics, Mechanical Engineering Faculty, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland.
This study delves into the intricate mechanics of human middle ear implants by examining a lumped parameter model with five degrees of freedom to estimate sound transfer. The ASTM standard, recognized globally as a benchmark, served as a reference for analysis, ensuring test accuracy and providing a comprehensive evaluation framework. To assess the implant's usability, numerical simulations were conducted and compared against both the ASTM standard and the experimental results obtained from temporal bone studies.
View Article and Find Full Text PDFJ Adv Res
December 2024
National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address:
Introduction: Crop rotation, a crucial agricultural practice that enhances soil health and crop productivity, is widely used in agriculture worldwide. Soybeans play a crucial role in crop rotation owing to their nitrogen-fixing ability, which is facilitated by symbiotic bacteria in their root systems. The soybean-rapeseed rotation is an effective agricultural practice in the Yangtze River Basin of China.
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