Self-organization Phenomena Research Articles

Higher order interactions in complex networks of phase oscillators promote abrupt synchronization switching

Synchronization processes play critical roles in the functionality of a wide range of both natural and man-made systems. Recent work in physics and neuroscience highlights the importance of higher-order interactions between dynamical units, i.e., three- and four-way interactions in addition to pairwise interactions, and their role in shaping collective behavior. Here we show that higher-order interactions between coupled phase oscillators, encoded microscopically in a simplicial complex, give rise to added nonlinearity in the macroscopic system dynamics that induces abrupt synchronization transitions via hysteresis and bistability of synchronized and incoherent states. Moreover, these higher-order interactions can stabilize strongly synchronized states even when the pairwise coupling is repulsive. These findings reveal a self-organized phenomenon that may be responsible for the rapid switching to synchronization in many biological and other systems that exhibit synchronization without the need of particular correlation mechanisms between the oscillators and the topological structure.

Percolation effects and self-organization processes in cold-pressed Bi2(Te1−xSex)3 solid solutions

Abstract It was established that the dependences of thermoelectric and mechanical properties of cold-pressed Bi2(Te1−xSex)3 alloys on composition (x = 0–0.07) exhibit a non-monotonic behavior in certain concentration ranges: an anomalous decrease in the Seebeck coefficient, thermoelectric power factor, and microhardness, and increase in electrical conductivity with increasing x. We observed similar anomalies earlier for cast Bi2(Te1−xSex)3 alloys and explained them by percolation and self-organization phenomena. Thus, the existence of the anomalies does not depend on the method of sample preparation. However, in pressed samples as compared to cast ones conductivity type changes from p to n and thermoelectric power factor increases.

Modeling and Simulation of Crowd Evacuation With Signs at Subway Platform: A Case Study of Beijing Subway Stations

Emergency signage systems provide effective route guidance and evacuation information for pedestrians in case of emergencies such as fire, blackout, and explosion. This paper proposes a modified social force (SF) model to investigate crowd evacuation dynamics taking into account the influence of emergency signs. The perceiving probability model is formulated for the quantitative description of the probability that pedestrians can successfully notice the sign and clearly perceive the guidance information. Simulation experiments and controlled experiments are designed to calibrate the parameters of the proposed model. The effectiveness of the modified SF model is preliminarily verified by comparing the simulation results with experimental data and/or empirical results such as fundamental diagrams and self-organization phenomena. A case study of crowd evacuation simulations at a typical Beijing subway station is conducted to evaluate evacuation performance of three signage distribution schemes, i.e., Maximal Covering (MaxCover), Uniform, and Random, which are proposed by the maximal covering location and empirical approaches, as well as contrasted scheme without emergency signs. The effects of the quantity and distribution of emergency signs on crowd evacuation efficiency are studied quantitatively by simulations. The results show that installing emergency signs can improve evacuation efficiency no matter what distribution scheme is adopted. By choosing an appropriate distribution scheme i.e., MaxCover, the evacuation performance can be further improved and the evacuation time can be significantly reduced.

Detecting Earthquake-Related Anomalies of a Borehole Strain Network Based on Multi-Channel Singular Spectrum Analysis.

To investigate the nonlinear spatio-temporal behavior of earthquakes, a complex network has been built using borehole strain data from the southwestern endpoint of the Longmenshan fault zone, Sichuan-Yunnan region of China, and the topological structural properties of the network have been investigated based on data from 2011–2014. Herein, six observation sites were defined as nodes and their edges as the connections between them. We introduced Multi-channel Singular Spectrum Analysis (MSSA) to analyze periodic oscillations, earthquake-related strain, and noise in multi-site observations, and then defined the edges of the network by calculating the correlations between sites. The results of the daily degree centrality of the borehole strain network indicated that the strain network anomalies were correlatable with local seismicity associate with the earthquake energy in the strain network. Further investigation showed that strain network anomalies were more likely to appear before major earthquakes rather than after them, particularly within 30 days before an event. Anomaly acceleration rates were also found to be related to earthquake energy. This study has revealed the self-organizing pre-earthquake phenomena and verified the construction of borehole networks is a powerful tool for providing information on earthquake precursors and the dynamics of complex fault systems.

Molecular and Cellular Mechanisms of Arthritis in Children and Adults: New Perspectives on Applied Photobiomodulation.

Juvenile idiopathic arthritis and adult rheumatoid arthritis are two major groups with chronic joint pain and inflammation, extra-articular manifestations, and high risk of comorbidities, which can cause physical and ocular disability, as well as create great socio-economic pressure worldwide. The pathogenesis of arthritis manifested in childhood and adulthood is multifactorial, unclear, and overly complex, in which immunity plays an important role. Although there are more and more biological agents with different mechanisms of action for the treatment of arthritis, the results are not as expected, because there are partial responses or non-responsive patients to these compounds, high therapeutic costs, side effects, and so on; therefore, we must turn our attention to other therapeutic modalities. Updating knowledge on molecular and cellular mechanisms in the comparative pathogenesis of chronic arthritis in both children and adults is necessary in the early and correct approach to treatment. Photobiomodulation (PBM) represents a good option, offering cost-effective advantages over drug therapy, with a quicker, more positive response to treatment and no side effects. The successful management of PBM in arthritis is based on the clinician’s ability to evaluate correctly the inflammatory status of the patient, to seek the optimal solution, to choose the best technology with the best physical parameters, and to select the mode of action to target very precisely the immune system and the molecular signaling pathways at the molecular level with the exact amount of quantum light energy in order to obtain the desired immune modulation and the remission of the disease. Light is a very powerful tool in medicine because it can simultaneously target many cascades of immune system activation in comparison with drugs, so PBM can perform very delicate tasks inside our cells to modulate cellular dysfunctions, helping to initiate self-organization phenomena and finally, healing the disease. Interdisciplinary teams should work diligently to meet these needs by also using single-cell imaging devices for multispectral laser photobiomodulation on immune cells.

A new heuristics model of simulating pedestrian dynamics based on Voronoi diagram* *Project supported by the National Natural Science Foundation of China (Grant Nos. 71771013 and 71621001), in part by the National Key Research and Development Program of China (Grant No. 2019YFF0301403), in part by the Singapore Ministry of Education (MOE) AcRF Tier 2 (Grant No. MOE2016-T2- 1-044), and in

A new heuristics model based on the Voronoi diagram is presented to simulate pedestrian dynamics with the non-crowded state, in which these mechanisms of preference demand evading and surpassing, microscopic anti-deadlock, and site-fine-tuning are considered. The preference demand describes the willingness determination of detouring or following other pedestrians. In the evading and surpassing mechanisms, in order to achieve a balance between avoiding conflicts and minimizing detour distances, a new pair of concepts: “allow-areas and denial-areas” are introduced to divide the feasible region for pedestrians detour behaviors, in which the direction and magnitude of detour velocity are determined. A microscopic anti-deadlock mechanism is inserted to avoid deadlock problem of the counter-directional pedestrian. A site-fine-tuning mechanism is introduced to describe the behavior of avoiding getting too close to the neighbors in pedestrian movement. The presented model is verified through multiple scenarios, including the uni- or bi-direction pedestrian flow in the corridor without obstacles, the uni-direction pedestrian flow in the corridor with obstacles, and the pedestrian evacuation from a room with single-exit. The simulation results show that the velocity–density relationship is consistent with empirical data. Some self-organizing phenomena, such as lanes formation and arching are observed in the simulation. When pedestrians detour an obstacle, the avoiding area before the obstacle and the unoccupied area after the obstacle can be observed. When pedestrians evacuate through a bottleneck without panic, the fan-shaped crowd can be found, which is consistent with the actual observation. It is also found that the behavior of following others in an orderly manner is more conducive to the improvement of the overall movement efficiency when the crowd moves in a limited space.

Self-organization of multiple anodic double layers in magnetized plasma

We report on the self-organization of multiple double layers (MDLs) and self-organized criticality (SOC) behavior through subsequent layer reduction process around the anode during DC glow discharge in a linear cylindrical vacuum vessel. The present study provides an insight into the characteristic features of self-organized MDLs around the anode itself and the effect of an external magnetic field during its evolution. The MDL formations around the anode initiate through an abrupt jump in the floating potential, ion saturation, and discharge current signals, which suggests an associated sheath—plasma instability of the system. The frequency spectrum of the floating potential exhibits mixed mode oscillations, which later disappears on applying an external magnetic field. The comparative results reveal the complex nature of a simple glow discharge through repeated coupling and decoupling of MDL dynamics during layer reduction process in the presence of an external magnetic field in cusp configuration, while the discharge turns largely oscillatory in the presence of an external magnetic field in mirror configuration. Existence of the SOC behavior in the system is further investigated through nonlinear dynamical analysis of the floating potential fluctuations. The present study on self-organization phenomena in a glow discharge plasma is important for applications regarding utilization or mitigation of self-organization. Self-organized patterns are often formed during plasma interaction with the liquid surface, which play a vital role in diverse applications of plasmas in nanomaterial synthesis and medicine.

Novel Tunable Spatio-Temporal Patterns From a Simple Genetic Oscillator Circuit.

Multicellularity, the coordinated collective behavior of cell populations, gives rise to the emergence of self-organized phenomena at many different spatio-temporal scales. At the genetic scale, oscillators are ubiquitous in regulation of multicellular systems, including during their development and regeneration. Synthetic biologists have successfully created simple synthetic genetic circuits that produce oscillations in single cells. Studying and engineering synthetic oscillators in a multicellular chassis can therefore give us valuable insights into how simple genetic circuits can encode complex multicellular behaviors at different scales. Here we develop a study of the coupling between the repressilator synthetic genetic ring oscillator and constraints on cell growth in colonies. We show in silico how mechanical constraints generate characteristic patterns of growth rate inhomogeneity in growing cell colonies. Next, we develop a simple one-dimensional model which predicts that coupling the repressilator to this pattern of growth rate via protein dilution generates traveling waves of gene expression. We show that the dynamics of these spatio-temporal patterns are determined by two parameters; the protein degradation and maximum expression rates of the repressors. We derive simple relations between these parameters and the key characteristics of the traveling wave patterns: firstly, wave speed is determined by protein degradation and secondly, wavelength is determined by maximum gene expression rate. Our analytical predictions and numerical results were in close quantitative agreement with detailed individual based simulations of growing cell colonies. Confirming published experimental results we also found that static ring patterns occur when protein stability is high. Our results show that this pattern can be induced simply by growth rate dilution and does not require transition to stationary phase as previously suggested. Our method generalizes easily to other genetic circuit architectures thus providing a framework for multi-scale rational design of spatio-temporal patterns from genetic circuits. We use this method to generate testable predictions for the synthetic biology design-build-test-learn cycle.

Frequency Synchronization and Its Possible Role in Microworld Phenomena

We note the active interest of Yu.I. Neimark for research of frequency synchronization, as well as his substantial support for research in this area. In this work we discuss the main, not yet fully established, definitions and concepts of the theory of frequency synchronization. We consider significant differences between the phenomena of synchronization, self-synchronization, and entrainment. We emphasize that self-synchronization belongs to the class of self-organization phenomena, which is often ignored. We list some relevant unsolved problems of the theory of frequency synchronization, among them being the question of the possible fundamental role of synchronization in the microworld, which is discussed in detail. We express an opinion that it is advisable to attempt to describe physical reality by unified deterministic laws of physics, taking into account other new achievements in nonlinear dynamics listed in this work.

Нестабильность и неопределенность развития жизненного пути человека в точках жизненной бифуркации

Man and his individual way of life are the most complex objects of scientific research. In modern humanitarian knowledge, the question of the nature of man and his life path is debatable. The article continues the cycle of author's works devoted to the development of an informational approach to self-organization of a person and his life path. The relevance of the study is due to the need for a scientific explanation of the phenomena of self-organization in the development of human life. The purpose of this work is to identify the effect of instability and uncertainty on the development of a person’s life path at points of vital bifurcation. The article gives the author’s definition of a person’s life path, analyzes the existence of a person in conditions of intrapersonal instability and uncertainty, and the development of human life at points of vital bifurcation. The results of the study allow us to consider instability and uncertainty as a necessary condition for the emergence of processes of self-organization of a person’s life path at the point of vital bifurcation. The main research methods are reflection and modeling.

Self-ordering and cavity cooling using a train of ultrashort pulses

A dilute atomic gas in an optical resonator exhibits a phase transition from a homogeneous density to crystalline order when laser illuminated orthogonal to the resonator axis. We study this well-known self-organization phenomenon for a generalized pumping scheme using a femtosecond pulse train with a frequency spectrum spanning a large bandwidth covering many cavity modes. We show that due to simultaneous scattering into adjacent longitudinal cavity modes the induced light forces and the atomic dynamics becomes nearly translation-invariant along the cavity axis. In addition the laser bandwidth introduces a new correlation length scale within which clustering of the atoms is energetically favorable. Numerical simulations allow us to determine the self-consistent ordering threshold power as function of bandwidth and atomic cloud size. We find strong evidence for a change from a second order to a first order self-ordering phase transition with growing laser bandwidth when the size of the atomic cloud gets bigger than the clustering length. An analysis of the cavity output reveals a corresponding transition from a single to a double pulse traveling within the cavity. This doubles the output pulse repetition rate and creates extra substructures in close analogy to a time crystal formation in the cavity output. Simulations also show that multi-mode operation significantly improves cavity cooling generating lower kinetic temperatures at a much faster cooling rate.

Swarms on the 3-sphere for online clustering of multivariate time series and data streams

We propose a novel algorithm named SwarmStream for real-time clustering of multivariate time series and data streams. The algorithm is inspired by phenomena of self-organization in complex systems. The data are processed by a swarm whose motions are governed by the system of matrix ordinary differential equations (ODEs) on the matrix group SU(2) with the group manifold S3. Such systems of matrix ODEs are referred to as non-Abelian Kuramoto models in Physics. With each object we associate one generalized oscillator and encode its attributes into the corresponding frequency matrix. The underlying idea is that oscillators with similar frequencies will synchronize their motions due to the internal communication within the swarm. The method is illustrated in several short videos, demonstrating evolution of clusters in some sets of evolving multivariate data.

Simulation of bi-directional pedestrian flow through a bottleneck: Cell transmission model

We propose an extended cell transmission model with regular hexagonal cell representation to simulate the bi-directional pedestrian flow through a bottleneck. We take humility behavior among pedestrians into the model as a set of parameters. Without loss of generality, this model simulates the boarding and alighting process of passengers for a specific scenario, i.e., the platform area of train or subway. By numerical simulations, we find that the parameters representing humility behavior have significant influence on the fundamental diagrams and the density distribution of pedestrians. By setting the humility parameters reasonably, the congestion can be alleviated and the total boarding and alighting time can be reduced. Moreover, by analyzing the effects of different widths of bottleneck, the conclusion that the pedestrian flow increases linearly as the bottleneck width increases can be obtained. By comparing two different boarding and alighting rules, it can be suggested that the general rule “alighting first and boarding second” may not always be the most effective one. Some self-organization phenomena, including following and avoidance behavior, spillback, dissipation, and lane formation are also shown in this paper.

Freak chimera states in a locally coupled Duffing oscillators chain

Arrays of oscillators driven out-of-equilibrium can support the coexistence between coherent and incoherent domains that have become known as chimera states. Recently, we have reported such an intriguing self-organization phenomenon in a chain of locally coupled Duffing oscillators. Based on this prototype model, we reveal a generalization of chimera states corresponding to the coexistence of incoherent domains. These freak states emerge through a bifurcation in which the coherent domain of an existing chimera state experiences an instability giving rise to another incoherent state. Using Lyapunov exponents and Fourier analysis allows us to characterize the dynamical nature of these extended solutions. Taking the Kuramoto order parameter, we were able to compute the bifurcation diagram of freak chimera states.

Design of resilient socio-technical systems by human-system co-creation

The concept of resilience is commonly used to represent “an ability to adapt to a changing environment and to survive flexibly despite facing difficulties.” This definition of resilience emphasized its aspects of unpredictable responsiveness to external disturbances as well as self-organized phenomena, which seemed to be close to the definition of complex adaptive systems. This article summarizes the technical challenges to consider the implementation of a concept of resilience into systems from a variety of perspectives. Then, challenges to tackle with the resilience to variabilities in production plans, in work quality, in empirical knowledge, in human-automation systems, and in organizations are presented.

Noise-Induced Stop-and-Go Dynamics in Pedestrian Single-file Motion

Stop-and-go waves are a common feature of vehicular traffic and have also been observed in pedestrian flows. Usually the occurrence of this self-organization phenomenon is related to an inertia mechanism. It requires fine-tuning of the parameters and is described by instability and phase transitions. Here, we present a novel explanation for stop-and-go waves in pedestrian dynamics based on stochastic effects. By introducing coloured noise in a stable microscopic inertia-free (i.e. first order) model, pedestrian stop-and-go behaviour can be described realistically without requirement of instability and phase transition. We compare simulation results to empirical pedestrian trajectories and discuss plausible values for the model’s parameters.

On the Evidence of Thermodynamic Self-Organization during Fatigue: A Review.

In this review paper, the evidence and application of thermodynamic self-organization are reviewed for metals typically with single crystals subjected to cyclic loading. The theory of self-organization in thermodynamic processes far from equilibrium is a cutting-edge theme for the development of a new generation of materials. It could be interpreted as the formation of globally coherent patterns, configurations and orderliness through local interactivities by “cascade evolution of dissipative structures”. Non-equilibrium thermodynamics, entropy, and dissipative structures connected to self-organization phenomenon (patterning, orderliness) are briefly discussed. Some example evidences are reviewed in detail to show how thermodynamics self-organization can emerge from a non-equilibrium process; fatigue. Evidences including dislocation density evolution, stored energy, temperature, and acoustic signals can be considered as the signature of self-organization. Most of the attention is given to relate an analogy between persistent slip bands (PSBs) and self-organization in metals with single crystals. Some aspects of the stability of dislocations during fatigue of single crystals are discussed using the formulation of excess entropy generation.

New insights into the reactionary zones excited-state programming by plasma-acoustic coupling mechanism for the next-generation small satellite solid propulsion systems

Small satellites are changing the game for deep space missions because can work together in a fleet to take on more complex missions. Smart control by excited-state of the reactionary zones is one of the keys to access to the properties of the solid propellants reactionary zones. In particular, the self-organized wave patterns excitation occurs at excited-state of the reactionary zones. Use of the plasma-acoustic coupling mechanism is one of the advanced ways to access to the properties of the reactionary zones: the scale and localization of the induction and energy-releasing areas. On the base of detailed analysis we suggest the new concept for the reactionary zones programming by the plasma arc force field emitter with application of the self-organized wave patterns excitation phenomenon. The innovative aspect of this concept is the plasma-acoustic coupling mechanism that transforms the input electrical energy into the directed acoustic energy. Suggested concept for manipulating by self-organized wave patterns in the reactionary zones with using of the plasma arc force field emitters and new generation of the electrically activated solid propellants is opening the door for completely new ways for producing extremely small thrust impulses for the extra-precise attitude control of the small satellites.

A study of self-organization of scientific communications: from statistical patterns to law

The article considers statistical laws of scientific communications and describes the phenomena and processes of self-organization in library science, science of science, and linguistics. Synergetics is chosen as the methodological basis of research.The aim of the study is to develop a synergistic concept of the emergence of statistical laws of information processes and phenomena in scientific communications for their generalization and presentation in the form of a single law.The concept of synergetics is developed for scientific communications as a manifestation of objectively existing but theoretically unsubstantiated quantitative relations between the subjects and objects of these communications (scientists, publications, and terms). The necessity of using stable distribution laws of probability theory for describing scale-invariant phenomena and processes is noted. In the mathematical sense, the stability of the distribution law is the property of preserving its type for any sum of random variables having this distribution. The mathematical abstraction of a ‘random variable' in scientific communications takes on a clear concreteness. For Bradford's regularity, the random variable is the number of articles on a particular topic in the journal; for Lotka's regularity, it is the number of scholar's publications; and for Zipf's regularity, it is the frequency of using the word in the text.The study has determined the characteristic indicator of the stable law of the distribution of processes and phenomena in scientific communications, which is equal to the constant of the golden section.A synergistic concept of scientific communications is formulated as follows: scale-invariant processes and phenomena of self-organization are a manifestation of a stable distribution law of probability theory with a characteristic indicator equal to the constant of the golden ratio

Scaling in the Local Strain-Rate Field during Jerky Flow in an Al-3%Mg Alloy

Jerky flow in alloys, or the Portevin-Le Chatelier effect, presents an outstanding example of self-organization phenomena in plasticity. Recent acoustic emission investigations revealed that its microscopic dynamics is governed by scale invariance manifested as power-law statistics of intermittent events. As the macroscopic stress serrations show both scale invariance and characteristic scales, the micro-macro transition is an intricate question requiring an assessment of intermediate behaviors. The first attempt of such an investigation is undertaken in the present paper by virtue of a one-dimensional (1D) local extensometry technique and statistical analysis of time series. The data obtained complete the missing link and bear evidence to a coexistence of characteristic large events and power laws for smaller events. The scale separation is interpreted in terms of the phenomena of self-organized criticality and synchronization in complex systems. Furthermore, it is found that both the stress serrations and local strain-rate bursts agree with the so-called fluctuation scaling related to general mathematical laws and unifying various specific mechanisms proposed to explain scale invariance in diverse systems. Prospects of further investigations including the duality manifested by a wavy spatial organization of the local bursts of plastic deformation are discussed.