A5054911802- Nonlinear Dynamics and Pattern Formation
- stochastic dynamics and bifurcation
- Neural dynamics and brain function
- Advanced Thermodynamics and Statistical Mechanics
- Fluid Dynamics and Turbulent Flows
- Mechanical and Optical Resonators
- Slime Mold and Myxomycetes Research
- Theoretical and Computational Physics
- Chaos control and synchronization
- Neural Networks Stability and Synchronization
- Complex Network Analysis Techniques
- Fluid Dynamics and Vibration Analysis
- Micro and Nano Robotics
- Energy Efficient Wireless Sensor Networks
- Opinion Dynamics and Social Influence
- Laser-Plasma Interactions and Diagnostics
- Photoreceptor and optogenetics research
- Nuclear Physics and Applications
- Complex Systems and Time Series Analysis
- Mineral Processing and Grinding
- Indoor and Outdoor Localization Technologies
- Drilling and Well Engineering
- Evolution and Paleontology Studies
- Radioactive contamination and transfer
- Control Systems and Identification
Japan Agency for Marine-Earth Science and Technology
2013-2025
Akita University
2019
Tokyo Institute of Technology
2014
Keio University
2013
Kyoto University
2004-2007
Renesas Electronics (Japan)
2007
Japan Atomic Energy Agency
2003
Osaka Electro-Communication University
1999-2003
University of Tsukuba
2002
Kanazawa University
1987-1989
We study synchronization properties of general uncoupled limit-cycle oscillators driven by common and independent Gaussian white noises. Using phase reduction averaging methods, we analytically derive the stationary distribution difference between for weak noise intensity. demonstrate that in addition to synchronization, clustering, or more generally coherence, always results from arbitrary initial conditions, irrespective details oscillators.
Reaction-diffusion systems can describe a wide class of rhythmic spatiotemporal patterns observed in chemical and biological systems, such as circulating pulses on ring, oscillating spots, target waves, rotating spirals. These dynamics be considered limit cycles reaction-diffusion systems. However, the conventional phase-reduction theory, which provides simple unified framework for analyzing synchronization properties limit-cycle oscillators subjected to weak forcing, has mostly been...
Synchronization analysis of real-world systems is essential across numerous fields, including physics, chemistry, and life sciences. Generally, the governing equations these are unknown, thus, phase calculated from measurements. Although existing calculation techniques designed for oscillators that possess no spatial structure, methods handling spatiotemporal dynamics remain undeveloped. The presence structure complicates determination which measurements should be used accurate calculation....
This paper presents results of conceptual design activities and associated R&D a solid breeder blanket system for demonstration power generation fusion reactors (DEMO blanket) cooled by supercritical water. The Fusion Council Japan developed the long-term research development programme in 1999. To make DEMO reactor more attractive, higher thermal efficiency than 40% was strongly recommended. meet this requirement, carried out. In conjunction with design, new concept water proposed technology...
The collective phase response to a macroscopic external perturbation of population interacting nonlinear elements exhibiting oscillations is formulated for the case globally coupled oscillators. sensitivity derived from microscopic constituent oscillators by two-step reduction. We apply this result quantify stability common-noise-induced synchronization two uncoupled populations undergoing coherent oscillations.
We present a phase-based framework for reducing the pressure fluctuations within spanwise-periodic supersonic turbulent cavity flow with an incoming free-stream Mach number of 1.4 and depth-based Reynolds 10,000. Open flows exhibit large due to feedback between shear layer instabilities acoustic field. The dominant physics includes formation, convection, impingement large-scale spanwise-oriented vortical structures. formulate control strategy effectively modify vortex convection frequency,...
Accurate knowledge of the instrument transfer function (ITF) is vital for topography measurements using white‐light interferometry (WLI). To this end, we derive a complete set analytical expressions power spectral density (PSD) discretely-sampled binary pseudo‐random array (BPRA) as theoretical benchmark. We then determine ITF by comparing PSD with measured BPRA. For Zygo ZeGage™ Pro HR 50× objective, determined closely matches nominal modulation (MTF). Accordingly, integrate MTF into...
Accurate knowledge of the instrument transfer function (ITF) is vital for topography measurements using white‐light interferometry (WLI). To this end, we derive a complete set analytical expressions power spectral density (PSD) discretely-sampled binary pseudo‐random array (BPRA) as theoretical benchmark. We then determine ITF by comparing PSD with measured BPRA. For Zygo ZeGage™ Pro HR 50× objective, determined closely matches nominal modulation (MTF). Accordingly, integrate MTF into...
Accurate knowledge of the instrument transfer function (ITF) is vital for topography measurements using white‐light interferometry (WLI). To this end, we derive a complete set analytical expressions power spectral density (PSD) discretely-sampled binary pseudo‐random array (BPRA) as theoretical benchmark. We then determine ITF by comparing PSD with measured BPRA. For Zygo ZeGage™ Pro HR 50× objective, determined closely matches nominal modulation (MTF). Accordingly, integrate MTF into...
We formulate a reduction theory that describes the response of an oscillator network as whole to external forcing applied nonuniformly its constituent oscillators. The phase description multiple networks coupled weakly is also developed. General formulae for collective sensitivity and effective coupling between are found. Our applicable wide variety undergoing frequency synchronization. Any structure can systematically be treated. A few examples given illustrate our theory.
We demonstrate that nonlocally coupled limit-cycle oscillators subject to spatiotemporally white Gaussian noise can exhibit a noise-induced transition turbulent states. After illustrating states with numerical simulations using two representative models of oscillators, we develop theory clarifies the effective dynamical instabilities leading behavior hierarchy reduction methods. determine parameter region where system states, which is successfully confirmed by extensive at each level reduction.
Phase synchronization between collective oscillations exhibited by two weakly interacting groups of non-identical phase oscillators with internal and external global sinusoidal coupling the is analyzed theoretically. Coupled amplitude equations describing oscillator are obtained using Ott-Antonsen ansatz, then coupled for derived reduction equations. The function, which determines dynamics macroscopic differences groups, calculated analytically. It demonstrated that can exhibit effective...
This paper presents a virtual humanoid robot platform (V-HRP for short) on which we can develop the identical controller and its real counterpart. The unification of controllers has been realized by introducing software adapters two robots respectively employing ART-Linux real-time processing is available at user level. Thanks to unification, share softwares with dynamics simulator V-HRP, including parameter parser, kinematics computations collision detector. feature make development more...
Nonlocally coupled oscillator systems can exhibit an exotic spatiotemporal structure called a chimera, where the system splits into two groups of oscillators with sharp boundaries, one which is phase locked and other randomized. Two examples chimera states are known: first appears in ring oscillators, second associated two-dimensional rotating spiral waves. In this paper, we report yet another example state that so-called Ising walls one-dimensional spatially extended systems. This exhibited...
Biological rhythms are generated by pacemaker organs, such as the heart organ (the sinoatrial node) and master clock of circadian suprachiasmatic nucleus), which composed a network autonomously oscillatory cells. Such biological have notable periodicity despite internal external noise present in each cell. Previous experimental studies indicate that regularity dynamics is enhanced when noisy oscillators interact become synchronized. This effect, called collective enhancement temporal...
We formulate a theory for the collective phase description of oscillatory convection in Hele-Shaw cells. It enables us to describe dynamics by single degree freedom which we call phase. The can be considered as reduction method limit-cycle solutions infinite-dimensional dynamical systems, namely, stable time-periodic partial differential equations, representing convection. derive sensitivity function, quantifies response weak perturbations applied at each spatial point, and analyze...
We obtain an optimal actuation waveform for fast synchronization of periodic airfoil wakes through the phase reduction approach. Using approach wake flows, spatial sensitivity fields with respect to vortex shedding are obtained. The can uncover properties in presence actuation. This study seeks a using phase-based analysis minimize time modify frequency NACA0012 wakes. is obtained theoretically from function by casting optimization problem. becomes increasingly non-sinusoidal higher angles...
No abstract available. <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.6.06.2008" target="_blank">10.2204/iodp.sd.6.06.2008</a>
We develop a theory of collective phase description for globally coupled noisy excitable elements exhibiting macroscopic oscillations. Collective equations describing rhythms the system are derived from Langevin-type active rotators via nonlinear Fokker-Planck equation. The is an extension conventional reduction method ordinary limit cycles to limit-cycle solutions in infinite-dimensional dynamical systems, such as time-periodic representing rhythms. demonstrate that type sensitivity...
We formulate a theory for the collective phase description of globally coupled noisy limit-cycle oscillators exhibiting macroscopic rhythms. Collective equations describing such rhythms are derived by means two-step reduction. The sensitivity and coupling functions, which quantitatively characterize rhythms, illustrated using three representative models oscillators. As an important result theory, we demonstrate noise-induced anti-phase synchronization between direct numerical simulations models.
A general phase reduction method for a network of coupled dynamical elements exhibiting collective oscillations, which is applicable to arbitrary networks heterogeneous elements, developed. set adjoint equations sensitivity functions, characterize response the oscillation small perturbations applied individual derived. Using under weak perturbation can be described approximately by one-dimensional equation. As an example, mutual synchronization between pair collectively oscillating excitable...
Many systems, ranging from biological and engineering systems to social can be modeled as directed networks, with links representing interaction between two nodes. To assess the importance of a node in network, various centrality measures based on different criteria have been proposed. However, calculating is often difficult because overwhelming size network or information held about incomplete. Thus, developing an approximation method for estimating needed. In this study, we focus modular...
We formulate a theory for the phase description of oscillatory convection in cylindrical Hele-Shaw cell that is laterally periodic. This system possesses spatial translational symmetry lateral direction owing to shape as well temporal symmetry. Oscillatory this described by limit-torus solution two modes; one and other phase. The phases indicate position oscillation convection, respectively. developed paper can be considered reduction method solutions infinite-dimensional dynamical systems,...
We consider optimization of linear stability synchronized states between a pair weakly coupled limit-cycle oscillators with cross coupling, where different components state variables the are allowed to interact. On basis phase reduction theory, coupling matrix oscillator that maximizes under given constraints on overall intensity and stationary difference is derived. The improvement in illustrated by using several types as examples.