Adaptive synchronization in delay-coupled networks of Stuart-Landau oscillators

We consider networks of delay-coupled Stuart-Landau oscillators. In these systems, the coupling phase has been found to be a crucial control parameter. By proper choice of this parameter one can switch between different synchronous oscillatory states of the network. Applying the speed-gradient method, we derive an adaptive algorithm for an automatic adjustment of the coupling phase such that a desired state can be selected from an otherwise multistable regime. We propose goal functions based on both the difference of the oscillators and a generalized order parameter and demonstrate that the speed-gradient method allows one to find appropriate coupling phases with which different states of synchronization, e.g., in-phase oscillation, splay or various cluster states, can be selected.Comment: 8 pages, 7 figure

Controlling cluster synchronization by adapting the topology

We suggest an adaptive control scheme for the control of zero-lag and cluster synchronization in delay-coupled networks. Based on the speed-gradient method, our scheme adapts the topology of a network such that the target state is realized. It is robust towards different initial condition as well as changes in the coupling parameters. The emerging topology is characterized by a delicate interplay of excitatory and inhibitory links leading to the stabilization of the desired cluster state. As a crucial parameter determining this interplay we identify the delay time. Furthermore, we show how to construct networks such that they exhibit not only a given cluster state but also with a given oscillation frequency. We apply our method to coupled Stuart-Landau oscillators, a paradigmatic normal form that naturally arises in an expansion of systems close to a Hopf bifurcation. The successful and robust control of this generic model opens up possible applications in a wide range of systems in physics, chemistry, technology, and life science

An improved time-delay implementation of derivative-dependent feedback

We consider an LTI system of relative degree that can be stabilized using output derivatives. The derivatives are approximated by finite differences leading to a time-delayed feedback. We present a new method of designing and analyzing such feedback under continuous-time and sampled measurements. This method admits essentially larger time-delay/sampling period compared to the existing results and, for the first time, allows to use consecutively sampled measurements in the sampled-data case. The main idea is to present the difference between the derivative and its approximation in a convenient integral form. The kernel of this integral is hard to express explicitly but we show that it satisfies certain properties. These properties are employed to construct the Lyapunov–Krasovskii functional that leads to LMI-based stability conditions. If the derivative-dependent control exponentially stabilizes the system, then its time-delayed approximation stabilizes the system with the same decay rate provided the time-delay (for continuous-time measurements) or the sampling period (for sampled measurements) are small enough

Predictor-based networked control under uncertain transmission delays

We consider state-feedback predictor-based control of networked control systems with large time-varying communication delays. We show that even a small controller-to-actuators delay uncertainty may lead to a non-small residual error in a networked control system and reveal how to analyze such systems. Then we design an event-triggered predictor-based controller with sampled measurements and demonstrate that, depending on the delay uncertainty, one should choose various predictor models to reduce the error due to triggering. For the systems with a network only from a controller to actuators, we take advantage of the continuously available measurements by using a continuous-time predictor and employing a recently proposed switching approach to event-triggered control. By an example of an inverted pendulum on a cart we demonstrate that the proposed approach is extremely efficient when the uncertain time-varying network-induced delays are too large for the system to be stabilizable without a predictor

C,N-chelated diaminocarbene platinum(II) complexes derived from 3,4-diaryl-1H-pyrrol-2,5-diimines and cis-dichlorobis(isonitrile)platinum(II):Synthesis, cytotoxicity, and catalytic activity in hydrosilylation reactions

The reaction of 3,4-diaryl-1H-pyrrol-2,5-diimines with cis-dichlorobis(isonitrile)platinum(II) affords the C,N-chelated diaminocarbene platinum(II) complexes, which have been fully characterized including molecular spectroscopy, single crystal X-ray diffraction and DFT calculations. The obtained platinum(II) complexes are effective catalysts for the hydrosilylation of alkynes and alkenes. Thus, the reaction of phenylacetylene with triethoxysilane leads to the formation of α- and β-(E)-vinylsilanes, generating TON's in the range of 103 to 104 and TOF's in the range of 102 to 103 h−1. Also, the cross-linked silicones, possessing the luminescence properties, were obtained by the hydrosilylation reaction of vinyl- and hydride-containing polysiloxanes. Additionally, the efficiency of diaminocarbene platinum(II) complexes against CH1/PA-1, SW480, and A549 cancer cell lines has been demonstrated by in vitro cytotoxicity studies.peerReviewe

Survey on time-delay approach to networked control

This paper provides a survey on time-delay approach to networked control systems (NCSs). The survey begins from a brief summary on fundamental network-induced issues in NCSs and the main approaches to the modelling of NCSs. In particular, a comprehensive introduction to time-delay approach to sampled-data and networked control is provided. Then, recent results on time-delay approach to event-triggered control are recalled. The survey highlights time-delay approach developed to modelling, analysis and synthesis of NCSs, under communication constraints, with a particular focus on Round-Robin, Try-once-discard and stochastic protocols. The time-delay approach allows communication delays to be larger than the sampling intervals in the presence of scheduling protocols. Moreover, some results on networked control of distributed parameter systems are surveyed. Finally, conclusions and some future research directions are briefly addressed

Experience herb relocation for preserving its population during reconstruction period

The article is devoted to the experience of transplantation Anemone nemorosa L., listed in the Red book of the Vladimir region as a rare species (status category 3). A feature of this work is transplanting in the autumn period, in connection with the construction of a natural place of growth, in accordance with the conclusion of environmental impact assessment. The aim of the work was to preserve the aboriginal population in natural conditions that are close in their ecological characteristics to the natural place of growth and which do not fall into the zone of reconstruction. Methods. We used the geobotanical description method, soil selection methods, and laboratory methods. Results. The data of the geobotanical description of the initial and recipient habitats of the Anemone nemorosa and soil characteristics are presented. The method of plant transplantation is described in detail. Conclusion. The phenollogical observations made in May 2019 showed that Anemone nemorosa successfully transferred the autumn transplant to a new place. An artificial population of Anemone oakwood was formed, which requires further monitoring studies for adaptation and resistance to transplantation

The research of fluoride ions concentration in household water supply

Poor quality water is the second risk factor after poverty for diseases dynamics. Fluorine is important for human health, and since the main route for its introduction into the body is water, hygienic assessment of drinking water quality based on the content of this microelement at the regional level is very relevant, thus it has become our research objective.Eight districts of the region are characterized by such fluoride content in water which is significantly lower than optimal values; five districts by the concentrations exceeding maximum permissible values; and only three districts by approximately optimal average values. Different concentration of fluoride in the regional water supplies depends on the natural factor of this geographical zone. To provide the population of the region with high-quality drinking water a complex of various measures including the development and implementation of programs for improving local water supplies are required

Ecological and hygienic assessment of environment in the town with glass packaging production

The population of the industrialized centers is constantly affected by the complex of technogenic factors of environmental pollution. The leading technogenic factor is known to impact negatively the population health is air pollution. Technogenic air pollution in cities is caused by the emissions of contaminants both as a result of motor transportation and industrial enterprises. This impact is one of the main reasons for the public health deterioration. Glass production is among such sources. Air pollution with toxic substances causes soil pollution, which ecological and sanitary condition can serve as a marker of environmental pollution rate. The study objective was the ecological and hygienic environment assessment of the Gorokhovets town in the Vladimir region, where modern glass empties production is functioning. Statistics of the regional official services in Gorokhovets district of the Vladimir region, as well as data from our own research have been applied for the research. Heavy metals in soil have been detected by x-ray fluorescence method applying spectrometer “Spectroscan MAX-G”. Anions content in soils was determined using water extracts from soil samples by capillary electrophoresis applying device “Kapel-104”. Results. The statistics published by the official regional state services on the gross amount of air pollutants emissions have been analyzed. Data on the heavy metals (HM) and anions content in various parts of Gorokhovets have been obtained. Conclusion. The ecologic-hygienic assessment of environment allowed to reveal that vehicles make the largest contribution to the air pollution in Gorohovets area in recent years. The main stationary air pollution source n is the glass works “Rusdzham” as first of all nitrogen oxides are its by-products