Stochastic synchronization in globally coupled phase oscillators

Cooperative effects of periodic force and noise in globally Cooperative effects of periodic force and noise in globally coupled systems are studied using a nonlinear diffusion equation for the number density. The amplitude of the order parameter oscillation is enhanced in an intermediate range of noise strength for a globally coupled bistable system, and the order parameter oscillation is entrained to the external periodic force in an intermediate range of noise strength. These enhancement phenomena of the response of the order parameter in the deterministic equations are interpreted as stochastic resonance and stochastic synchronization in globally coupled systems.Comment: 5 figure

Competitive resource vrio-profile of a high-tech enterprise

Achieving competitive success of Russian high-tech enterprises in the conditions of economy of knowledge, technology and innovation is largely driven by the effective use and accelerated development of their own resource base. In this regard, there is a need for continuous monitoring and analysis of the enterprises’ resource potential dynamics. The aim of this article is to develop a methodological tool for assessing the competitiveness of high-tech industrial enterprises on the basis of indicators characterizing the manifestation rate of competitive properties in the resources. The proposed method furthers theoretical and methodological aspects of the resource theory developed by Jay Barney, in particular the qualitative assessment the VRIO framework parameters: Value, Rarity, Inimitability and Organization. The scientific novelty of the research consists in the interpretation of the VRIO criteria set, the development of quantitative methods for calculation of their parameters and combining numeric values of these criteria in the integral evaluation - a competitive resource VRIO-profile of the enterprise. Its use allows us to carry out in-house analysis of the status and dynamics of the resource potential, to identify timely negative trends in the development of resources competitive properties, to select reasonable management strategies in order to improve competitiveness, and also to define priority measures within an innovative development program of high-tech enterprises. The practical importance of this research is that its results and conclusions can be used in strategic economic activity planning of high-tech industrial enterprises. Separate theoretical and methodological positions can be of interest to educational institutions and research organizations and applied in the development and implementation of programs to enhance competitiveness.Достижение конкурентного успеха российских высокотехнологичных предприятий в условиях экономики знаний, технологий и инноваций в значительной степени обусловливается эффективным использованием и ускоренным развитием их собственной ресурсной базы. В связи с этим возникает потребность в непрерывном мониторинге и анализе динамики развития ресурсного потенциала данных предприятий. Целью настоящей статьи является разработка методического инструмента оценки конкурентоспособности высокотехнологичных промышленных предприятий на базе индикаторов, характеризующих степень проявления в ресурсах конкурентных свойств. Предложенная методика развивает теоретические и методологические аспекты ресурсной теории Джея Барни в части количественной оценки ресурсных параметров: ценности (Value), редкости (Rarity), неимитируемости (Inimitability) и организованности (Organization). Научная новизна исследования состоит в интерпретации набора критериев VRIО, разработке методики расчета их параметров и объединении численных показателей этих критериев в интегральную оценку - конкурентный ресурсный VRIO-профиль предприятия. Его применение позволяет проводить внутрифирменный анализ состояния и динамики ресурсного потенциала, своевременно выявлять негативные тенденции в формировании конкурентных свойств ресурсов, а также обоснованно подходить к выбору управленческой стратегии повышения конкурентоспособности и определять приоритетные мероприятия в рамках реализации программ инновационного развития высокотехнологичных предприятий. Практическая значимость данного исследования заключается в том, что его результаты и выводы могут быть использованы в стратегическом планировании хозяйственной деятельности современных высокотехнологичных промышленных предприятий. Отдельные теоретические и методологические положения работы могут представлять интерес для университетов и исследовательских организаций и применяться при разработке и реализации программ повышения конкурентоспособности

From regional pulse vaccination to global disease eradication: insights from a mathematical model of Poliomyelitis

Mass-vaccination campaigns are an important strategy in the global fight against poliomyelitis and measles. The large-scale logistics required for these mass immunisation campaigns magnifies the need for research into the effectiveness and optimal deployment of pulse vaccination. In order to better understand this control strategy, we propose a mathematical model accounting for the disease dynamics in connected regions, incorporating seasonality, environmental reservoirs and independent periodic pulse vaccination schedules in each region. The effective reproduction number, $R_e$, is defined and proved to be a global threshold for persistence of the disease. Analytical and numerical calculations show the importance of synchronising the pulse vaccinations in connected regions and the timing of the pulses with respect to the pathogen circulation seasonality. Our results indicate that it may be crucial for mass-vaccination programs, such as national immunisation days, to be synchronised across different regions. In addition, simulations show that a migration imbalance can increase $R_e$ and alter how pulse vaccination should be optimally distributed among the patches, similar to results found with constant-rate vaccination. Furthermore, contrary to the case of constant-rate vaccination, the fraction of environmental transmission affects the value of $R_e$ when pulse vaccination is present.Comment: Added section 6.1, made other revisions, changed titl

Experimental Study of Noise-induced Phase Synchronization in Vertical-cavity Lasers

We report the experimental evidence of noise-induced phase synchronization in a vertical cavity laser. The polarized laser emission is entrained with the input periodic pump modulation when an optimal amount of white, gaussian noise is applied. We characterize the phenomenon, evaluating the average frequency of the output signal and the diffusion coefficient of the phase difference variable. Their values are roughly independent on different waveforms of periodic input, provided that a simple condition for the amplitudes is satisfied. The experimental results are compared with numerical simulations of a Langevin model

Synchronization and resonance in a driven system of coupled oscillators

We study the noise effects in a driven system of globally coupled oscillators, with particular attention to the interplay between driving and noise. The self-consistency equation for the order parameter, which measures the collective synchronization of the system, is derived; it is found that the total order parameter decreases monotonically with noise, indicating overall suppression of synchronization. Still, for large coupling strengths, there exists an optimal noise level at which the periodic (ac) component of the order parameter reaches its maximum. The response of the phase velocity is also examined and found to display resonance behavior.Comment: 17 pages, 3 figure

Phase synchronization and noise-induced resonance in systems of coupled oscillators

We study synchronization and noise-induced resonance phenomena in systems of globally coupled oscillators, each possessing finite inertia. The behavior of the order parameter, which measures collective synchronization of the system, is investigated as the noise level and the coupling strength are varied, and hysteretic behavior is manifested. The power spectrum of the phase velocity is also examined and the quality factor as well as the response function is obtained to reveal noise-induced resonance behavior.Comment: to be published in Phys. Rev.

Multifractal characterization of stochastic resonance

We use a multifractal formalism to study the effect of stochastic resonance in a noisy bistable system driven by various input signals. To characterize the response of a stochastic bistable system we introduce a new measure based on the calculation of a singularity spectrum for a return time sequence. We use wavelet transform modulus maxima method for the singularity spectrum computations. It is shown that the degree of multifractality defined as a width of singularity spectrum can be successfully used as a measure of complexity both in the case of periodic and aperiodic (stochastic or chaotic) input signals. We show that in the case of periodic driving force singularity spectrum can change its structure qualitatively becoming monofractal in the regime of stochastic synchronization. This fact allows us to consider the degree of multifractality as a new measure of stochastic synchronization also. Moreover, our calculations have shown that the effect of stochastic resonance can be catched by this measure even from a very short return time sequence. We use also the proposed approach to characterize the noise-enhanced dynamics of a coupled stochastic neurons model.Comment: 10 pages, 21 EPS-figures, RevTe

Drugs foresight 2020: a Delphi expert panel study

Peer reviewe

Radioluminescence properties of nanocomposite scintillators with BaF 2 fillers

In this paper, studies of the luminescence properties of nanocrystalline BaF 2 samples synthesized by laser ablation and pulse electron beam evaporation method are presented. The measurements of X-ray excited luminescence (XEL) showed the dependence between luminescence intensity and the shape of the spectrum on the morphology and particle size. Also, studies of X-ray excited luminescence, decay curves and optical transmittance for nanocomposite materials containing BaF 2 nanopowder are presented. Barium fluoride nanopowder, obtained by pulsed electron beam evaporation method is characterized by a lower intensity than the initial microcrystalline powder, but at the same time, XEL spectrum of the nanocomposite material with this nanocrystalline filler is more intense, then that for nanocomposite material with initial powder. © Published under licence by IOP Publishing Ltd