Two-dimensional spatiotemporal complexity in dual-delayed nonlinear feedback systems: Chimeras and dissipative solitons

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Chaos 28, 103106 (2018) and may be found at https://doi.org/10.1063/1.5043391.We demonstrate for a photonic nonlinear system that two highly asymmetric feedback delays can induce a variety of emergent patterns which are highly robust during the system’s global evolution. Explicitly, two-dimensional chimeras and dissipative solitons become visible upon a space-time transformation. Switching between chimeras and dissipative solitons requires only adjusting two system parameters, demonstrating self-organization exclusively based on the system’s dynamical properties. Experiments were performed using a tunable semiconductor laser’s transmission through a Fabry-Pérot resonator resulting in an Airy function as nonlinearity. Resulting dynamics were bandpass filtered and propagated along two feedback paths whose time delays differ by two orders of magnitude. An excellent agreement between experimental results and the theoretical model given by modified Ikeda equations was achieved. Photonic delay systems are of astonishing diversity and have created a rich field of fundamental research and a wide range of applications. Under a transformation from time into pseudo-scape, their basic architecture makes them equivalent to ring networks with perfectly-symmetric coupling. For the first time we extend this spatiotemporal analogy in experiments by adding a second delay, 100 times the length of the first delay line. Nonlinearity is provided by a tunable semiconductor laser traversing a Fabry-Pérot resonator. Visualized in 2D-space, we show the temporal evolution of different chimeras and dissipative solitons. Experimental results excellently agree with numerical simulations of the double-delay bandpass Ikeda equation. Based on the attractors of multiple fixed-point solutions, we provide insight into the mechanism structuring the system’s dynamics.DFG, 163436311, SFB 910: Kontrolle selbstorganisierender nichtlinearer Systeme: Theoretische Methoden und Anwendungskonzept

Cascades of Multi-headed Chimera States for Coupled Phase Oscillators

Chimera state is a recently discovered dynamical phenomenon in arrays of nonlocally coupled oscillators, that displays a self-organized spatial pattern of co-existing coherence and incoherence. We discuss the appearance of the chimera states in networks of phase oscillators with attractive and with repulsive interactions, i.e. when the coupling respectively favors synchronization or works against it. By systematically analyzing the dependence of the spatiotemporal dynamics on the level of coupling attractivity/repulsivity and the range of coupling, we uncover that different types of chimera states exist in wide domains of the parameter space as cascades of the states with increasing number of intervals of irregularity, so-called chimera's heads. We report three scenarios for the chimera birth: 1) via saddle-node bifurcation on a resonant invariant circle, also known as SNIC or SNIPER, 2) via blue-sky catastrophe, when two periodic orbits, stable and saddle, approach each other creating a saddle-node periodic orbit, and 3) via homoclinic transition with complex multistable dynamics including an "eight-like" limit cycle resulting eventually in a chimera state.Comment: 13 pages, 14 figure

Multi-Agent Security System based on Neural Network Model of User's Behavior

It is proposed an agent approach for creation of intelligent intrusion detection system. The system allows detecting known type of attacks and anomalies in user activity and computer system behavior. The system includes different types of intelligent agents. The most important one is user agent based on neural network model of user behavior. Proposed approach is verified by experiments in real Intranet of Institute of Physics and Technologies of National Technical University of Ukraine "Kiev Polytechnic Institute”

Network-induced multistability through lossy coupling and exotic solitary states

The stability of synchronised networked systems is a multi-faceted challenge for many natural and technological fields, from cardiac and neuronal tissue pacemakers to power grids. For these, the ongoing transition to distributed renewable energy sources leads to a proliferation of dynamical actors. The desynchronisation of a few or even one of those would likely result in a substantial blackout. Thus the dynamical stability of the synchronous state has become a leading topic in power grid research. Here we uncover that, when taking into account physical losses in the network, the back-reaction of the network induces new exotic solitary states in the individual actors and the stability characteristics of the synchronous state are dramatically altered. These effects will have to be explicitly taken into account in the design of future power grids. We expect the results presented here to transfer to other systems of coupled heterogeneous Newtonian oscillators

ДОСЛІДЖЕННЯ ЕЛЕКТРИЧНОГО ПОЛЯ У ДУГОВІЙ СТАЛЕПЛАВИЛЬНІЙ ПЕЧІ З МЕТОЮ ВИЗНАЧЕННЯ КРИТЕРІЇВ ДЛЯ ОПТИМІЗАЦІЇ ЕНЕРГОСПОЖИВАННЯ

The given results of theoretical research allow to define the distribution of actual power in arc furnace cavity by means of integral equation system using secondary sources method. The received results are basis for creation of software that supports operation of industrial computers, which have ability to run the arc furnace in order to improve energy consumption.Приведенные результаты проведенных теоретических исследований позволяют определить распределение активной мощности в полости дуговой сталеплавильной печи с помощью системы интегральных уравнений с использованием метода вторичных источников. Полученные результаты являются основанием для создания программ, обеспечивающих роботу промышленных компьютеров, которые способны управлять дуговыми сталеплавильными печами, с целью оптимизации затрат электроэнергии.Наведені результати проведених теоретичних досліджень дозволяють визначити розподіл активної потужності в порожнині дугової сталеплавильної печі за допомогою системи інтегральних рівнянь з використанням методу вторинних джерел. Отримані результати є підґрунтям для створення програм, які забезпечують роботу промислових комп’ютерів, що спроможні керувати дуговими сталеплавильними печами, з метою оптимізації витрат електроенергії

ВИКОРИСТАННЯ КОНФОРМНИХ ВІДОБРАЖЕНЬ ДЛЯ ДОСЛІДЖЕННЯ ЕЛЕКТРОФІЗИЧНИХ ПАРАМЕТРІВ ТЕЧІЇ РОЗПЛАВУ МЕТАЛУ В ЕЛЕКТРОДУГОВІЙ СТАЛЕПЛАВИЛЬНІЙ ПЕЧІ

The results of theoretical researches carried out using the conformal maps to define electrophysical parameters melt flow in the electric arc furnaces taking in account the purposeful action of magnetic field are proposed. On the basis of the proposed method using conformal maps becomes possible to determine the tractive force at each point of the melt metal.Предложена методика проведения теоретических исследований с помощью конформных отображений для определения электрофизических параметров течения расплава металла в электросталеплавильных печах с учётом целенаправленного действия магнитного поля. На основании предложенной методики использования конформного отображения появляется возможность определить тяговое усилие в каждой точке расплава.Запропонована методика проведення теоретичних досліджень за допомогою конформних відображень щодо визначення електрофізичних параметрів течії розплаву металу в електросталеплавильних печах з урахуванням цілеспрямованої дії магнітного поля. На підставі запропонованої методики використання конформного відображення є можливим визначити тягове зусилля у кожній точці розплаву

Efficiency of Finding Muon Track Trigger Primitives in CMS Cathode Strip Chambers

In the CMS Experiment, muon detection in the forward direction is accomplished by cathode strip chambers~(CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using~36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge~(MTCC) exercise conducted by the~CMS experiment in~2006. In contrast to earlier studies that used muon beams to illuminate a very small chamber area ($< \! 0.01$~m$^2$), results presented in this paper were obtained by many installed CSCs operating {\em in situ} over an area of $\approx \! 23$~m$^2$ as a part of the~CMS experiment. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be~$99.93 \pm 0.03\%$. These segments, found by the CSC electronics within $800$~ns after the passing of a muon through the chambers, are the input information for the Level-1 muon trigger and, also, are a necessary condition for chambers to be read out by the Data Acquisition System

Measurement of the Average Lifetime of b-Hadrons in Z Decays

We present a measurement of the average b-hadron lifetime ${\rm \tau_b}$ at the $\mathrm{e^+e^-} \,$ collider LEP. Using hadronic Z decays collected in the period from 1991 to 1994, two independent analyses have been performed. In the first one, the b-decay position is reconstructed as a secondary vertex of hadronic b-decay particles. The second analysis is an updated measurement of ${\rm \tau_b}$ using the impact parameter of leptons with high momentum and high transverse momentum. The combined result is \begin{center} ${\rm \tau_b= [ 1549 \pm 9 \, (stat) \, \pm 15 \, (syst) ] \; fs \,}$ . \end{center} In addition, we measure the average charged b-decay multiplicity ${\rm \langle n_{\rm b}} \rangle$ and the normalized average b-energy ${\rm \langle x_E \rangle_{\rm b}}$ at LEP to be \begin{center} ${\rm \langle n_{\rm b} \rangle = 4.90 \pm 0.04 \ (stat) \pm 0.11 \, (syst)}$ , \end{center} \begin{center} ${\rm \langle x_E \rangle_{\rm b} = 0.709 \pm 0.004 \, (stat + syst).}$ \end{center

Production of Single W Bosons at LEP

We report on the observation of single W boson production in a data sample collected by the L3 detector at LEP2. The signal consists of large missing energy final states with a single energetic lepton or two hadronic jets. The cross-section is measured to be $0.61^{+0.43}_{-0.33} \pm 0.05 \; \rm{pb}$ at the centre of mass energy \sqrt{s}=172 \GeV{}, consistent with the Standard Model expectation. From this measurement the following limits on the anomalous $\gamma$WW gauge couplings are derived at 95\% CL: $\rm -3.6 \Delta \kappa_\gamma 1.5$ and $\rm -3.6 \lambda_\gamma 3.6$