scholarly journals Some Sampling Properties of Common Phase Estimators

2013 ◽  
Vol 25 (4) ◽  
pp. 901-921 ◽  
Author(s):  
Kyle Q. Lepage ◽  
Mark A. Kramer ◽  
Uri T. Eden
Keyword(s):  
Model Misspecification ◽  
Analytical Investigation ◽  
Statistical Sampling ◽  
Neural Signals ◽  
Data Share ◽  
Common Features ◽  
Instantaneous Phase ◽  
Three Phase ◽  
Geometric Argument ◽  
Hilbert Complex

The instantaneous phase of neural rhythms is important to many neuroscience-related studies. In this letter, we show that the statistical sampling properties of three instantaneous phase estimators commonly employed to analyze neuroscience data share common features, allowing an analytical investigation into their behavior. These three phase estimators—the Hilbert, complex Morlet, and discrete Fourier transform—are each shown to maximize the likelihood of the data, assuming the observation of different neural signals. This connection, explored with the use of a geometric argument, is used to describe the bias and variance properties of each of the phase estimators, their temporal dependence, and the effect of model misspecification. This analysis suggests how prior knowledge about a rhythmic signal can be used to improve the accuracy of phase estimates.

scholarly journals Inferring Functional Neural Connectivity with Phase Synchronization Analysis: A Review of Methodology

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Junfeng Sun ◽  
Zhijun Li ◽  
Shanbao Tong
Keyword(s):  
Functional Connectivity ◽  
Phase Synchronization ◽  
Significance Test ◽  
Neural Connectivity ◽  
Neural Signals ◽  
Instantaneous Phase ◽  
Neuroscience Research ◽  
Observational Noise ◽  
Relationship Of ◽  
The Relationship

Functional neural connectivity is drawing increasing attention in neuroscience research. To infer functional connectivity from observed neural signals, various methods have been proposed. Among them, phase synchronization analysis is an important and effective one which examines the relationship of instantaneous phase between neural signals but neglecting the influence of their amplitudes. In this paper, we review the advances in methodologies of phase synchronization analysis. In particular, we discuss the definitions of instantaneous phase, the indexes of phase synchronization and their significance test, the issues that may affect the detection of phase synchronization and the extensions of phase synchronization analysis. In practice, phase synchronization analysis may be affected by observational noise, insufficient samples of the signals, volume conduction, and reference in recording neural signals. We make comments and suggestions on these issues so as to better apply phase synchronization analysis to inferring functional connectivity from neural signals.

Analytical investigation on the minimum traffic delay at a three-phase signalized T-type intersection

2017 ◽  
Vol 31 (06) ◽  
pp. 1750063
Author(s):  
Hong-Ze Zhang ◽  
Rui Jiang ◽  
Mao-Bin Hu ◽  
Bin Jia
Keyword(s):  
Analytical Investigation ◽  
Urban Traffic ◽  
Traffic System ◽  
3D Space ◽  
Three Phase ◽  
Minimum Delay ◽  
Traffic Delay

The traffic delay at intersections is crucial for the performance of urban traffic system. This paper analytically investigated the minimum traffic delay at a three-phase T-type intersection. We firstly demonstrate that the minimum traffic delay must be achieved on the surface of the 3D space constituted by the three constraints. Next, we prove that the minimum traffic delay must be achieved on the three borderlines of the surface. Finally, we show that the minimum delay is achieved either on one specific borderline or at the vertex of the surface. In the former case, extra green time is needed for the stream with largest demand, while no extra green time should be assigned to any stream in the latter case.

Detection of Induction Motors Faults Using Instantaneous Phase Variation

Volume 3 ◽  
2004 ◽  
Author(s):  
A. F. Saleh Alshandoli ◽  
F. Gu ◽  
A. D. Ball
Keyword(s):  
Single Phase ◽  
Phase Variation ◽  
Current Phase ◽  
Phase Method ◽  
Instantaneous Phase ◽  
Squirrel Cage ◽  
Squirrel Cage Induction Motor ◽  
Three Phase ◽  
Cage Induction Motor ◽  
Good Agreement

This paper presents a new method for detecting the most common faults of squirrel cage induction motor; namely broken rotor bars, voltage imbalance and rotor misalignment. The proposed method uses Hilbert transform to determine the current instantaneous phase variation (IPV) based on only one current phase instead of the three-phase method. The number of used channels was greatly reduced to the sixth while the results are in good agreement with that obtained using the three-phase method. Experimental results show good detection capability especially at full load conditions. In addition, a comparative study has also been made between the single-phase and the three-phase method.

scholarly journals Inductor Saturation Compensation in Three-Phase Three-Wire Voltage-Source Converters via Inverse System Dynamics-II

2020 ◽  
Author(s):  
Ziya Özkan ◽  
Ahmet Masum Hava
Keyword(s):  
Energy Conversion Efficiency ◽  
Analytical Investigation ◽  
Current Control ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Current Waveform ◽  
Inverse Dynamic ◽  
Figures Of Merit ◽  
Zero Current ◽  
Three Phase

Current waveform quality and current control bandwidth are the figures of merit for current controllers in three-phase three-wire (3P3W) voltage-source converter (VSC) systems. When saturable inductors are employed as converter side inductors due to cost, size, and energy conversion efficiency benefits in 3P3W VSCs with conventional synchronous frame current control (CSCC); substantial drawbacks arise by means of these figures of merit. In the preceding part of this study, an inverse dynamic model based compensation (IDMBC) method has been proposed to deal with these drawbacks. Complementarily, this paper presents a thorough analytical investigation of the control system characteristics of CSCC and IDMBC methods that affect the current waveform quality and current control bandwidth. The analyses are verified via dynamic response and waveform quality simulations and experiments that employ saturable inductors reaching $1/9^{th}$ of the zero-current inductance at full current. The results obtained demonstrate the suitability of the IDMBC method for 3P3W VSCs employing saturable inductors.

scholarly journals ELECTROCHEMISTRY OF IMMOBILIZED MICROPARTICLES AND MICRODROPLETE: ACCESS TO FUNDAMENTAL DATA OF SOLID MATERIALS AND IONS

2021 ◽  
Vol 87 (9) ◽  
pp. 55-60
Author(s):  
Fritz Scholz
Keyword(s):  
General Interest ◽  
Ion Transfer ◽  
Free Energies ◽  
Solid Materials ◽  
Common Features ◽  
Three Phase ◽  
Cooperation Partners ◽  
First Time ◽  
Electrode Technique

The idea to study the electrochemistry of immobilized microparticles has been published by this author for the first time in 1989. In the last 32 years, this approach has been shown to be very successful not only for analytical characterization of solid materials, but also applicable to extract thermodynamic and kinetic data, and even to determine the age of metal specimen. In 2000, it has been shown that the electrochemistry of immobilized microdroplets gives an elegant access to determine the Gibbs free energies of ion transfer between immiscible solvents. These measurements are performed with a standard 3-electrode potentiostate and can be used also for solvents, which cannot be used in experiments with the classical 4-electrode technique. The electrochemistry of microparticles and microdroplets share several common features with respect to the electrode mechanisms: in both cases three-phase electrodes are realized and ion and electron transfer proceed simultaneously. This talk reviews the activities of the speaker and his cooperation partners during the last 3 decades paying special attention to those results, which are of general interest.

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