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venerdì 2 giugno 2023

# gst: apropos of coexistence of coherent and incoherent oscillators, chaotic chimera attractors in a triangular network.

<< A prominent type of collective dynamics in networks of coupled oscillators is the coexistence of coherently and incoherently oscillating domains known as chimera states. >>️

<< In a three-population network of identical Kuramoto-Sakaguchi phase oscillators, stationary and periodic symmetric chimeras were previously studied on a reduced manifold in which two populations behaved identically. >>

<< In this paper, (AA) study the full phase space dynamics of such three-population networks. (They) demonstrate the existence of macroscopic chaotic chimera attractors that exhibit aperiodic antiphase dynamics of the order parameters. >>

<< The chaotic chimera states coexist with a stable chimera solution on the Ott-Antonsen manifold that displays periodic antiphase oscillation of the two incoherent populations and with a symmetric stationary chimera solution, resulting in tristability of chimera states. Of these three coexisting chimera states, only the symmetric stationary chimera solution exists in the symmetry-reduced manifold. >>️

Seungjae Lee, Katharina Krischer. Chaotic chimera attractors in a triangular network of identical oscillators. Phys. Rev. E 107, 054205. May 8, 2023.

Also: chimera, chaos, three balls, in https://www.inkgmr.net/kwrds.html

Keywwords: gst, chimera, bifurcations, chaos, synchronization


venerdì 26 maggio 2023

# gst: even a tiny noise could self-induce new chimera patterns through stochastic resonance


<< Noise induced order in excitable systems has diverse manifestations, such as coherence resonance (CR) and stochastic resonance. In this context a less explored phenomenon is self-induced stochastic resonance (SISR). Unlike CR, SISR may arise away from the bifurcation threshold and the properties of the induced oscillations depend upon both the noise intensity and the time-scale separation factor. In this work, (AA) report a new chimera pattern in a network of coupled excitable units, namely the self-induced stochastic resonance chimera or SISR-chimera that originates from the SISR phenomenon. (AA) explore the detailed dynamics of the SISR-chimera in the parameter space using proper quantitative measures. (AA) have found that unlike CR chimera, the SISR-chimera pattern strongly depends upon the ratio of time scale and noise intensity. Therefore, this type of chimera pattern can be induced even for a tiny noise intensity if the time scale separation of the activator and inhibitor is large enough. >>️

Taniya Khatun, Tanmoy Banerjee. Genesis of chimera patterns through self-induced stochastic resonance. arXiv:2305.06824v1 [nlin.AO]. May 11, 2023. 

Also:  chimera, noise, disorder in  https://www.inkgmr.net/kwrds.html  

Keywords: gst, noise, disorder, chimera, self-induced stochastic resonance chimera 




mercoledì 24 maggio 2023

# gst: intricate transitions in elastoactive structures.

<< The interplay between activity and elasticity often found in active and living systems triggers a plethora of autonomous behaviors ranging from self-assembly and collective motion to actuation. Among these, spontaneous self-oscillations of mechanical structures is perhaps the simplest and most widespread type of nonequilibrium phenomenon. >>️

<< Here, (AA) introduce a centimeter-sized model system for one-dimensional elastoactive structures. >>️

<< such structures exhibit flagellar motion when pinned at one end, self-snapping when pinned at two ends, and synchronization when coupled together with a sufficiently stiff link. (..) these transitions can be described quantitatively by simple models of coupled pendula with follower forces. >>️

Ellen Zheng, Martin Brandenbourger, et al. Self-Oscillation and Synchronization Transitions in Elastoactive Structures. Phys. Rev. Lett. 130, 178202. April 25, 2023. 

Also:  transition, particle, self-assembly, elastic, pendulum in https://www.inkgmr.net/kwrds.html

Keywords: gst, transition, particle, self-assembly, elastic, pendulum


domenica 14 maggio 2023

# jazz: when turbulence underneath it and on top of it.


<< The album title comes from poet and scholar Fred Moten, who described Gamedze's drumming in the internet forum Poesis as an "amazing interplay between turbulence and pulse. Pulse is supposed to regulate and also be regular, but the turbulence underneath it and on top of it, it's just extraordinary." >>️

Thom Jurek. Turbulence and Pulse. allmusic.com. May 5, 2023. 

Also: jazz, turbulence, in  https://www.inkgmr.net/kwrds.html

Keywords: jazz, turbulence



sabato 13 maggio 2023

# gst: the robustness of a edge spiking.


<< Excitable media, ranging from bioelectric tissues and chemical oscillators to forest fires and competing populations, are nonlinear, spatially extended systems capable of spiking. Most investigations of excitable media consider situations where the amplifying and suppressing forces necessary for spiking coexist at every point in space. In this case, spiking requires a fine-tuned ratio between local amplification and suppression strengths. But, in Nature and engineered systems, these forces can be segregated in space, forming structures like interfaces and boundaries. Here, (AA) show how boundaries can generate and protect spiking if the reacting components can spread out: even arbitrarily weak diffusion can cause spiking at the edge between two non-excitable media. This edge spiking is a robust phenomenon that can occur even if the ratio between amplification and suppression does not allow spiking when the two sides are homogeneously mixed. >> ️

Colin Scheibner, Hillel Ori, et al. Spiking at the edge. arXiv:2304.06940v1 [cond-mat.soft]. Apr 14, 2023. 


Keywords: gst, excitable media, weak, spike, edge spiking  




mercoledì 10 maggio 2023

# gst: to find a separation between plunging and spilling wave breakers


<< While understanding breaking waves is crucial for the development of parametrizations used in ocean wave modeling for both deep and shallow water, the complete process of wave breaking is not well understood. Here (AA) present direct numerical simulations of two-dimensional solitary waves that shoal and break on a uniform beach in shallow water, with the presence of storm surge represented by an inshore region. >>️

They << classify wave breaker types and find a separation between plunging and spilling breakers when scaled by breaking amplitude and depth. (AA) compare energy dissipation during the breaking process with results from the literature without storm surge.  >>️

They << conclude that a previously developed shallow-water inertial dissipation model for wave breaking on a uniform slope can be extended to this storm surge environment with good data collapse, and further discuss possibilities for a general parametrization of wave breaking valid across different depth regimes. >>️

Hunter Boswell, Guirong Yan, Wouter Mostert. Characterizing energy dissipation of shallow-water wave breaking in a storm surge. Phys. Rev. Fluids 8, 054801. May 5, 2023. 

Also: waves, soliton, drop, in https://www.inkgmr.net/kwrds.html

Keywords: gst, waves, soliton, drop 






martedì 9 maggio 2023

# life: exponential post-Donald (without Donald), how AI could interfere (drive) next political elections.

<< Recent news that the Republican National Committee (RNC) has used an AI-generated video to criticize Joe Biden shows how likely AI is to transform our upcoming elections. >>️

<< Through templates that are easy and inexpensive to use, we are going to face a Wild West of campaign claims and counter-claims, with limited ability to distinguish fake from real material and uncertainty regarding how these appeals will affect the election. >>️

<< In the coming year, response times may drop to minutes, not hours or days. AI can scan the internet, think about strategy, and come up with a hard-hitting appeal. >>️

<< AI provides an inexpensive way to generate instant responses without having to rely on highly-paid consultants or expert videographers. >>️

<< AI enables very precise audience targeting, which is crucial in political campaigns. >>️

<< AI likely will democratize disinformation by bringing sophisticated tools to the average person interested in promoting their preferred candidates as well. People no longer must be coding experts or video wizards to generate text, images, video, or programs. They don’t necessarily have to work for a troll farm to create havoc with the opposition. They can simply use advanced technologies to spread the messages they want. In that sense, anyone can become a political content creator and seek to sway voters or the media. >>️

Darrell M. West. How AI will transform the 2024 elections. May 3, 2023.

Also: 'ai', 'analogy', 'Potus', 'RAG-time', 'CTZ', 'Donald' in https://www.inkgmr.net/kwrds.html

Keywords: life, ai, analogy, potus, RAG, CTZ, Donald