Synchronous Parameters Research Articles

Влияние динамических характеристик датчиков дыхания на оценку кардиореспираторной синхронизации у больных с заиканием

Various types of sensors are used for assessment of diagnostic indicators based on the analysis of simultaneous measurements of respiration and ECG, such as cardiorespiratory synchronization. One of the most commonly used types of sensors is the thermal sensor, the advantages of which are the simplicity, the possibility to work without specialized masks, which is especially important in otolaryngology since it is often necessary to record speech breathing. The disadvantage of such sensors is the inertia, which should also be taken into consideration in the process of examination. The methods of cardiorespiratory synchronization assessment are sensitive to dynamic characteristics of respiratory sensors. To assess the degree of synchronization methods sensitivity to the dynamic characteristics of sensors is the main objective of this work. In this paper, we study the dynamic characteristics of the respiratory thermal sensor DDT-4-20, most commonly used in medical examinations, and its effect on cardiorespiratory synchronization parameters. An inertialess pressure sensor CJMCU-36 is used as a control device. The authors compare the cardiorespiratory synchronization indicators calculated by simultaneous measurements of inertial thermal sensor DDT-4-20 and inertialess pressure sensor CJMCU-36. It has been found that the inertia of the tested sensor slightly violates the synchronization ratio, the effect of the sensor inertia on the number and length of the inspiratory chains is more significant.

Исследование эффекта влияния временной задержки термической связи на синхронизацию VO-=SUB=-2-=/SUB=--осцилляторов

Abstract—The effect of the time delay of thermal coupling on the synchronization of two VO_2-oscillators has been studied for the first time. A modification of the methods for determining high order synchronization parameters has been proposed. The dependence of these parameters on the magnitude of the time delay and distance between the oscillators in the presence of internal noise has been studied. The results will contribute to the development of technology for creating three-dimensional neural networks.

Autocorrelation Function of Full-Response CPM Signals and Its Application to Synchronization

Two types of the autocorrelation functions of the full-response continuous phase modulation (CPM) signal are investigated in the paper, the autocorrelation functions are proven to be periodic functions when the modulation index of the CPM signal is h=1. Then the autocorrelation functions are expanded in the form of Fourier series, and two synchronization schemes are proposed to estimate the synchronization parameters from the coefficients of the Fourier series, including the carrier frequency offset, the carrier phase and the timing offset. The performances of the synchronization algorithms are shown by simulations and compared with the modified Cramer-Rao bounds (MCRB) and other synchronization schemes. The simulation results show that the first type of the proposed scheme has better synchronization performances than the available schemes.

A Robust approach for the identification of synchronous machine parameters and dynamic states based on PMU data

In this paper an approach for on-line identification of parameters and dynamic states of synchronous generator, is proposed. Synchrophasors data and Hybrid Dynamic Simulation provide the trajectories deviations caused by parameters errors. Simulated variables are combined with measurements to obtain Hybrid Trajectory Sensibility Functions (HTSF), which are used in the identification process based on Nonlinear Least Squares. This approach simplifies the calculation of HTSF. Constraints on the parameters range are enforced and the resulting constrained optimization problems is solved by a Primal-Dual Interior Points method. This solution is discussed in the paper. The method is applied to synthetic data and to a large generator of the Itaipu power plant.

Synchronization performance in time-delayed random networks induced by diversity in system parameter**Project supported by the National Natural Science Foundation of China (Grant Nos. 11675001, 11675112, 11775020, and 11372122).

Synchronization rhythm and oscillating in biological systems can give clues to understanding the cooperation and competition between cells under appropriate biological and physical conditions. As a result, the network setting is appreciated to detect the stability and transition of collective behaviors in a network with different connection types. In this paper, the synchronization performance in time-delayed excitable homogeneous random networks (EHRNs) induced by diversity in system parameters is investigated by calculating the synchronization parameter and plotting the spatiotemporal evolution pattern, and distinct impacts induced by parameter-diversity are detected by setting different time delays. It is found that diversity has no distinct effect on the synchronization performance in EHRNs with small time delay being considered. When time delay is increased greatly, the synchronization performance of EHRN degenerates remarkably as diversity is increased. Surprisingly, by setting a moderate time delay, appropriate parameter-diversity can promote the synchronization performance in EHRNs, and can induce the synchronization transition from the asynchronous state to the weak synchronization. Moreover, the bistability phenomenon, which contains the states of asynchronous state and weak synchronization, is observed. Particularly, it is confirmed that the parameter-diversity promoted synchronization performance in time-delayed EHRN is manifested in the enhancement of the synchronization performance of individual oscillation and the increase of the number of synchronization transitions from the asynchronous state to the weak synchronization. Finally, we have revealed that this kind of parameter-diversity promoted synchronization performance is a robust phenomenon.

A Procedure to Identify the Linear Models of Auxiliary Controllers of a Synchronous Machine

The absence of complete model data of a power system hinders complete eigenvalue analysis of that system. System identification methods have been used to identify operating-point-dependent equivalent linear model of a power system. Such identified models do not allow a complete eigenvalue analysis. To resolve this, the identification problem can be formulated in such a way to utilize any a-priori knowledge of the system. Model data of a synchronous machine consists of machine data and controller parameters. Methods to determine synchronous machine parameters are well established. In this paper, knowledge of the machine data and knowledge of eigenvalues of the system at multiple distinct operating points, extracted by a system identification method, are used to determine auxiliary controller parameters of the synchronous machine. Model data that are determined by the proposed method is independent of the operating point. Therefore, it can be easily integrated into a complete small signal stability study at any operating point of the synchronous machine.

Influence of Phasor Measurement Error on Parameter Identification for a Synchronous Generator

In this article, a method is presented to analyze the influence of phasor measurement errors on the parameter identification of synchronous generators. The equations describing the relationship between parameter deviation and phasor error are derived as based on the six-order model of a synchronous generator and the step-identification algorithm. Because parameter precision is important for the simulation and security operation of the power system, measurement errors, including those of current and voltage magnitudes and phase angles, are discussed to determine their influence on the identified parameters. In addition, through implementation of a practical example, the values of parameter errors directly resulting from phasor measurement errors are calculated via equations, and a simulation method is used to validate the effectiveness of the proposed equations. The results indicate that this method can be applied to identify any synchronous generator parameter, in addition to functioning as a reference to evaluate the identification algorithm and phasor measurement unit data quality.

Theoretical study on the elimination kinetics in the gas phase of allyl methyl compounds

The thermal decomposition kinetics of allyl methyl amine, allyl methyl ether, and allyl methyl sulfide in the gas phase has been studied theoretically using the M06-2x/aug-cc-pVTZ quantum chemical approach. The observed activation parameters are consistent with a concerted unimolecular mechanism involving a non-planar cyclic six-membered transition state. Based on the optimized ground state geometries, a natural bond orbital analysis of donor–acceptor interactions reveals that the stabilization energies corresponding to the electronic delocalization from the lone-pair (LP) non-bonding orbitals on the heteroatom to the neighboring $$\sigma_{{{\text{C2}} - {\text{C3}}}}^{*}$$ antibonding orbitals decrease from allyl methyl amine to allyl methyl sulfide. This delocalization fairly explains the increase of occupancies of LP orbitals on the heteroatom from allyl methyl sulfide to allyl methyl amine. The results also suggest that the kinetics of the thermolysis of the studied compounds are dominated by $${\text{LP}}\, \to \,\sigma^{*}$$ electronic delocalization effects. Analysis of bond order, bond indices, and synchronicity parameters demonstrates that these reactions proceed through a concerted and slightly asynchronous mechanism.

Research on Screening Method of Synchronous Generator Dominant Parameters Based on Trajectory Sensitivity

In order to reduce the complexity of synchronous generator dynamic parameter identification, the screening method of synchronous generator dominant parameters based on trajectory sensitivity is proposed. The mathematical model of trajectory sensitivity is established by the model and parameters of the generator. The influence degree of each parameter on the trajectory is calculated. According to the sensitivity of the trajectory, the sensitivity of dominant parameters Xd, Xq, Xd' and Xd of the generator is analyzed, and then the results of the trajectory sensitivity are verified by time domain simulation of IEEE 3-machines 9-node system.

Nonlinear network dynamics for interconnected micro-grids

This paper deals with transient stability in interconnected micro-grids. The main challenge is to understand the impact of the connectivity of the graph and model nonlinearities on transient and steady-state behavior of the system as a whole. The contribution of this paper is three-fold. First, we provide a robust classification of transient dynamics for different intervals of the parameters for a single micro-grid. We prove that underdamped dynamics and oscillations arise when the damping coefficient is below a certain threshold which we calculate explicitly as function of the product between the inertia coefficient and the synchronization parameter. Second, for interconnected micro-grids, under the hypothesis of homogeneity, we prove that the transient dynamics mimics a consensus dynamics. We provide bounds on the damping coefficient characterizing underdamped and overdamped consensus. Third, we extend the study to the case of disturbed measurements due to hackering or parameter uncertainties. We introduce model nonlinearities and prove absolute stability.

A New Method of Recording Generator Dynamics and Its Application to the Derivation of Synchronous Machine Parameters for Power System Stability Studies

The proposed algorithm is based on the discrete Fourier transform (DFT) and a software-based synchronous sampling technique that is locked to the power system frequency using reconfigurable field-programmable gate arrays (FPGAs). The main purposes of this paper are to provide a new method of recording the high-resolution rotor angle of a synchronous machine and a practical method for deriving more accurate d-q- axis synchronous machine parameters. An FPGA is used in realizing the rotor-angle transducer and it simultaneously detects the frequency of the generator terminal voltage. The DFT algorithm is combined with an interpolation technique that downsamples the high-frequency sampled data using the measured power system frequency. This paper also describes a practical method for determining synchronous machine model parameters. The proposed algorithm for recording the generator dynamics was implemented in terms of Labview, Real-Time PCI eXtensions for Instrumentation (PXI) target, and the FPGA, and was applied to generator testing of a 1205-MVA thermal power unit. Its synchronous machine parameters were also derived using the recorded rotor angle.

Accurate Two-Terminal Transmission Line Fault Location Using Traveling Waves

This paper presents an innovative two-terminal traveling wave (TW)-based fault location formulation. It depends only on the time difference between the first incident TW and the successive reflection from the fault point, at both line ends. Thereby, the proposed formulation requires neither data synchronization nor line parameters, which are sources of error that usually affect TW-based fault location schemes. Several faults on a typical 500 kV line were simulated to compare the proposed formulation performance with that of a classical two-end approach. The obtained results attest that the proposed formulation is able to accurately locate faults on transmission lines, even when data synchronism errors and uncertainties in the monitored line parameters exist.

On Complete Control and Synchronization of Zhang Chaotic System with Uncertain Parameters using Adaptive Control Method

Abstract Chaos control and synchronization of chaotic systems is seemingly a challenging problem and has got a lot of attention in recent years due to its numerous applications in science and industry. This paper concentrates on the control and synchronization problem of the three-dimensional (3D) Zhang chaotic system. At first, an adaptive control law and a parameter estimation law are achieved for controlling the behavior of the Zhang chaotic system. Then, non-identical synchronization of Zhang chaotic system is provided with considering the Lü chaotic system as the follower system. The synchronization problem and parameters identification are achieved by introducing an adaptive control law and a parameters estimation law. Stability analysis of the proposed method is proved by the Lyapanov stability theorem. In addition, the convergence of the estimated parameters to their truly unknown values are evaluated. Finally, some numerical simulations are carried out to illustrate and to validate the effectiveness of the suggested method.

A Novel Adaptive Active Control Projective Synchronization of Chaotic Systems

This paper investigates adaptive active control projective synchronization scheme. A general synchronization controller and parameter update laws are proposed to stabilize the error system for the identical structural chaotic systems. It is the first time that the active synchronization, the projective synchronization, and the adaptive synchronization are combined to achieve the synchronization of chaotic systems, which extend the control capability of achieving chaotic synchronization. By using a constant diagonal matrix, the active control is developed. Especially, when designing the controller, we just need to ensure that the diagonal elements of the diagonal matrix are less than or equal 0. So, the synchronization of chaotic systems can be realized more easily. Furthermore, by proposing an active controller, in combination with several different control schemes, we lower the complexity of the design process of the controller. More importantly, the larger the absolute value of product of the diagonal elements of diagonal matrix is, the smoother the curve of chaotic synchronization is and the shorter the time of chaotic synchronization is. In our paper, we take Lorenz system as an example to verify the effectiveness of the proposed synchronization scheme. Theoretical analysis and numerical simulations demonstrate the feasibility of this control method.

Effective estimation of angular speed of synchronous generator based on stator voltage measurement

Estimation of the parameters of the power generators are important part of a power system modeling and simulation. A reliable estimation of a synchronous generator parameters can be done using waveforms measured directly on the terminals of the machine. The waveforms are recorded during a carefully chosen disturbance tests of the generating unit. One of the quantities necessary to determine the generator parameters is the deviation of the generator angular speed. However, because of the safety reasons, it is very difficult to get access to the direct measurement of this quantity on a operating generating unit. Angular speed estimation based on a generator stator voltage seems to be an alternative solution to the problem.The aim of the paper is to find a computationally efficient and accurate method of indirect angular speed estimation of a synchronous generator which is based on the recording of its stator voltage during a load rejection test. The algorithms evaluated in the paper are based on Prony’s estimator, zero-crossing detection, least-square data fitting and layer recurrent neural network. Paper contains literature survey, mathematical model of the considered generator, analysis of its stator voltage recorded in a power plant, description of the selected algorithms and results of the algorithms estimation using a signal with known frequency variation. Performed algorithms evaluation allows to choose the best solution in terms of accuracy and computational effort.

PARAMETERS OF CARDIORESPIRATORY SYNCHRONISM AND THEIR DERIVATIVES IN THE ASSESSMENT OF THE FUNCTIONAL STATE WHEN RESTORING ERECTILE FUNCTION IN MEN AFTER PROSTATE CANCER TREATMENT METHOD HIFU

Aim. To assess the functional state in the recovery of erectile function in men after the treatment of cancer by HIFU, the parameters of cardiopulmonary synchronism and their derivatives. Materials and methods. Observations were performed on 24 patients aged 45-56 years, who were referred to the increase in the level of the prostatic specific antigen for inpatient treatment in the urological department. At their inspection the cancer of a prostate of I-II stage has been diagnosed. Patients underwent a cardiac-respiratory synchronism test and determined the regulatory-adaptive status index and regulatory-adaptive capabilities by its parameters. After diagnosis, patients were assigned tumor destruction by transrectal high-intensity focused ultrasound ablation. After the operation, the patients were discharged from the hospital the next day and further follow-up was conducted in an outpatient setting with a visit to the hospital at 1, 3, 6, 12 months. After 6 months, the sample of the cardiopulmonary synchronism was repeated. According to questionnaires subjective assessment of the international index of erectile function ICEF-5, the QOL index assessment of quality of life. Statistical analysis of the results of the study was carried out using the programs: "STATISTIKA 6.0 for Windows". After establishing the normal distribution of the variant, significant differences were used in comparing the mean values in paired comparisons, taking the t-test of Student for p <0,05. Results. Before treatment in a group of 24 patients, regulatory-adaptive capabilities were assessed as satisfactory. After treatment of prostate cancer with the method of transrectal high-intensity focused ultrasound ablation, the level of the prostatic specific antigen was sharply reduced from 6,81±0,32 to 0,70±0,01 ng/ml (p<0,001), the tumor volume from 39,8±0,4 to 8,5±0,3 cm3 (p<0,001). Six months after the treatment of prostate cancer, the synchronization range increased by 22,5%. The duration of synchronization development decreased by 39,1%. This led to an increase in the regulatory-adaptive status index by 100,6%. Regulatory adaptive capabilities varied from "satisfactory" to "good". Six months after the treatment of prostate cancer in patients, part of the prostate gland was preserved and ejaculation was possible. Erectile function resumed 6 months after surgery, when regulatory and adaptive capacities were restored. And in 16 people, whose index of regulatory-adaptive status was 77,9±0,4, the international index of erectile function was 23,8±0,1 points. This indicates that the state of erection is normal. The index of quality of life assessment QOL they had 0,9±0,1 points, which corresponds to a good quality of life. In 8 patients with a regulatory-adaptive status index of 44,6±0,4, the international index of erectile function was 18,2±0,3, indicating mild erectile dysfunction. The index of QOL quality of life was 2,1±0,2 points, which corresponds to a satisfactory quality of life. Conclusion. The positive dynamics of the range of cardiopulmonary synchronism, a decrease in the duration of synchronization at the minimal border, an increase in the index of regulatory-adaptive status and regulatory-adaptive capabilities integrally reflect the consequences of effective treatment of prostate cancer and, consequently, the preservation of erectile function.

Synchronous dynamics in neural system coupled with memristive synapse

To study the collective behavior and the regulation mechanism of memristor, the Hindmarsh–Rose neuron cells are selected as the units to construct a coupled system by using the cubic flux-controlled memristor as a connecting synapses, both the firing mode and synchronous behavior in this coupled system are investigated. In this paper, a coefficient is introduced to describe the effect of electromagnetic induction of membrane potential, and the weights of synaptic connection between cells are selected as an adjustable parameter. We have found that, on the one hand, for the certain external current, the firing pattern of neurons could maintain normal state induced by proper electromagnetic induction, and the transition between different firing states could also be observed. On the other hand, both the synchronous effects could be effectively enhanced and the domain of synchronous parameters could be also expanded by tuning the electromagnetic parameters. Particularly, when the coupled system is in the synchronization state, one can see that the firing behavior of neurons will simultaneously change with the varying of the memristance. The similar phenomenon could also be found by introducing the external stimulus signal with a certain frequency. It means that the plasticity of biological synapses could be effectively mimicked by using the memristive synapse and thus the effective memory function of the memristor to the external stimulus signal may be realized. Above results may not only provide some useful clues for understanding the dynamic behavior of neural system coupled with memristive synapses, but also afford us some inspiration to simulate human brain memory, forgetting or some other functions by using the memristor neural network in the future.

MRAS identification of permanent magnet synchronous motor parameters

This article deals with the identification of synchronous motor parameters with permanent magnets using the model-reference adaptive system (MRAS). This method can effectively identify two parameters. These parameters are the stator resistance and the BEMF, under certain conditions as well as the direct inductance. MRAS method is based on two different models. One of these is in our case a real motor and the other is a simulated model based on the identified parameter. This identification was verified in simulations and then applied to a real motor.

Estimación de los Parámetros Eléctricos de un Generador Sincrónico basada en Mediciones de Laboratorio usando Métodos de Optimización No Lineal

Este artículo presenta los resultados de la implementación de una metodología para la estimación de los parámetros eléctricos de un generador sincrónico basada en mediciones de laboratorio y utilizando métodos de optimización no lineal, con la finalidad de mejorar la representación de la máquina sincrónica que podría ser utilizada en estudios de sistemas eléctricos de potencia. Para ello se realizaron pruebas bajo la Norma IEEE 115 en el Laboratorio de Máquinas Eléctricas de la Escuela Politécnica Nacional. Estos parámetros obtenidos constituyen el punto de partida para la herramienta de estimación de parámetros que ayudará a sintonizar la respuesta de la máquina. Luego, se aplica una perturbación eléctrica a la máquina para obtener una respuesta experimental en forma de oscilograma. La perturbación se replica en MATLAB-Simulink para obtener la respuesta simulada de la máquina en la forma de un oscilograma. La etapa final utiliza como recurso la herramienta de identificación de parámetros de MATLAB-Simulink para sintonizar los parámetros eléctricos al modelo de la máquina sincrónica. Con la aplicación de esta metodología se encuentra que la respuesta simulada del generador sincrónico mejora y reproduce adecuadamente los valores medidos.

Gait Support by Changing Synchronization Parameter in Real Time Using curara

Gait Support by Changing Synchronization Parameter in Real Time Using curara