scholarly journals A Method to Obtain Parameters of One-Column Jansen–Rit Model Using Genetic Algorithm and Spectral Characteristics

2021 ◽  
Vol 11 (2) ◽  
pp. 677
Author(s):  
Adam Łysiak ◽  
Szczepan Paszkiel
Keyword(s):  
Genetic Algorithm ◽  
Amplitude Ratio ◽  
Spectral Characteristics ◽  
Intraclass Correlation ◽  
Nonlinear Function ◽  
Measured Signal ◽  
Eeg Signal ◽  
Potential Amplitude ◽  
Input Noise ◽  
Amplitude Maximum

In this paper, a method of obtaining parameters of one-column Jansen–Rit model was proposed. Methods present in literature are focused on obtaining parameters in an on-line manner, producing a set of parameters for every point in time. The method described in this paper can provide one set of parameters for a whole, arbitrarily long signal. The procedure consists of obtaining specific frequency features, then minimizing mean square error of those features between the measured signal and the modeled signal, using genetic algorithm. This method produces an 8-element vector, which can be treated as an EEG signal feature vector specific for a person. The parameters which were being obtained are maximum postsynaptic potential amplitude, maximum inhibitory potential amplitude, ratio of the number of connections between particular neuron populations, the shape of a nonlinear function transforming the average membrane potential into the firing rate and the input noise range. The method shows high reproducibility (intraclass correlation coefficient for particular parameters ranging from 0.676 to 0.978) and accuracy (ranging from 0.662 to 0.863). It was additionally verified using EEG signal obtained for a single participant. This signal was measured using Emotiv EPOC+ NeuroHeadset.

Analysis of a Pneumatically Coupled Cam-Actuated Mechanism

1981 ◽  
Vol 103 (3) ◽  
pp. 290-292
Author(s):  
S. LeQuoc ◽  
R. M. H. Cheng
Keyword(s):  
Amplitude Ratio ◽  
Nonlinear Function ◽  
Design Tool ◽  
Lumped Parameter Model ◽  
Design Parameters ◽  
Damping Factor ◽  
Resonance Amplitude ◽  
Orifice Area ◽  
Lumped Parameter ◽  
Wear And Tear

Cam-actuated mechanism with a pneumtic coupling is a design improvement upon the conventional system. Pneumatic dashpots are used which provide a cushioning effect, thus reducing the wear and tear of system components. This paper investigates the dynamic behavior of such a system based on a lumped parameter model with a damping factor which is a nonlinear function of the frequency. A digital computer is used as a design tool to determine the effect on the performance of changing design parameters. It is found that the system amplitude ratio peak depends largely upon the pneumatic damper orifice area and that a proper selection of the orifice area will yield a minimum resonance amplitude ratio.

scholarly journals Surface Roughness Optimization of Polyamide-6/Nanoclay Nanocomposites Using Artificial Neural Network: Genetic Algorithm Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Mehdi Moghri ◽  
Milos Madic ◽  
Mostafa Omidi ◽  
Masoud Farahnakian
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Surface Roughness ◽  
Artificial Neural Network ◽  
Predictive Model ◽  
Nonlinear Function ◽  
Polyamide 6 ◽  
Machining Performance ◽  
Milling Parameters ◽  
Artificial Neural

During the past decade, polymer nanocomposites attracted considerable investment in research and development worldwide. One of the key factors that affect the quality of polymer nanocomposite products in machining is surface roughness. To obtain high quality products and reduce machining costs it is very important to determine the optimal machining conditions so as to achieve enhanced machining performance. The objective of this paper is to develop a predictive model using a combined design of experiments and artificial intelligence approach for optimization of surface roughness in milling of polyamide-6 (PA-6) nanocomposites. A surface roughness predictive model was developed in terms of milling parameters (spindle speed and feed rate) and nanoclay (NC) content using artificial neural network (ANN). As the present study deals with relatively small number of data obtained from full factorial design, application of genetic algorithm (GA) for ANN training is thought to be an appropriate approach for the purpose of developing accurate and robust ANN model. In the optimization phase, a GA is considered in conjunction with the explicit nonlinear function derived from the ANN to determine the optimal milling parameters for minimization of surface roughness for each PA-6 nanocomposite.

scholarly journals Detection of radio signals against the background of strong electromagnetic noise in transport

2021 ◽  
Vol 2131 (5) ◽  
pp. 052046
Author(s):  
E Myasnikov ◽  
T Zaboronkova ◽  
L Kogan
Keyword(s):  
Background Noise ◽  
Nonlinear Function ◽  
High Sensitivity ◽  
Measured Signal ◽  
Mathematical Algorithm ◽  
Useful Signal ◽  
Random Components ◽  
Radio Signals ◽  
The Fourier Transform ◽  
Stochastic Phenomena

Abstract The problem of detecting a useful signal in the presence of a strong background noise is considered. To solve it, a statistical approach is used, based on a change in the level of chaos in the system when an additional random or deterministic process occurs, which is probabilistically independent from a set of stochastic phenomena that form background noise. It is shown that the occurrence of this process changes the level of entropy of the measured signal; this fact is the basis of the applied mathematical algorithm. It is based on the elements of the Fourier transform apparatus for the probability density with an appropriate choice of a nonlinear function of the random process under study. The proposed approach, based on variations in the randomness in the system in the presence of a useful signal, makes it possible to record its presence against the background of noise components even at low signal-to-noise ratios. The effectiveness of the method is confirmed both by theoretical justification and by the calculations presented in this work. The condition for the implementation of the technique described in the article, which does not impose restrictions on the studied physical fields and frequency ranges, is the comparability of the width of the probabilistic distribution of the desired useful signal with several intervals of discreteness of the measuring equipment. One of the results of this work is a high sensitivity to the emergence of independent random components.

Acquisition Method of Typical Time Course for Stationary Signal Basing on Frequency Weighting

2015 ◽  
Vol 734 ◽  
pp. 577-580
Author(s):  
Dan Lu ◽  
Yi Qi Zhou ◽  
Lei Liu ◽  
Yue Biao Chen
Keyword(s):  
Time Course ◽  
Spectral Characteristics ◽  
Noise Signal ◽  
Test Method ◽  
Measured Signal ◽  
Statistical Parameters ◽  
Typical Time ◽  
Actual Signal ◽  
Frequency Weighting ◽  
Acquisition Method

The cab acoustic response, which could be considered to be random and stationary, determines the riding comfort of the excavator. In order to get the most useful information from the actual cab noise signal, an acquisition method of typical time course for a stationary signal was proposed in this paper. Firstly, a series of de-noising preprocessing was applied on the test signal. Then, the stationarity and ergodicity of that were examined via runs test method. Finally, combining with FFT, IFFT and the frequency weighting, the typical time course was obtained. The results show that the statistical parameters and spectral characteristics of the obtained typical time course are consistent with those of the measured signal, which means that the obtained one could be regarded as a representation of the actual signal for further analyzing more effectively.

Reliability of Video Motion-Analysis Systems to Measure Amplitude and Velocity of Shoulder Elevation

2011 ◽  
Vol 20 (4) ◽  
pp. 393-405 ◽  
Author(s):  
Christopher Melton ◽  
David R. Mullineaux ◽  
Carl G. Mattacola ◽  
Scott D. Mair ◽  
Tim L. Uhl
Keyword(s):  
Outcome Measures ◽  
Average Velocity ◽  
Intraclass Correlation ◽  
Good Reliability ◽  
Amplitude Maximum ◽  
Cohort Differences ◽  
Video Motion Analysis ◽  
Shoulder Kinematics ◽  
Standard Error Of Measurement ◽  
Shoulder Elevation

Context:Dynamic shoulder motion can be captured using video capture systems, but reliability has not yet been established.Objective:To compare the reliability of 2 systems in measuring dynamic shoulder kinematics during forward-elevation movements and to determine differences in these kinematics between healthy and injured subjects.Design:Reliability and cohort.Setting:Research laboratory.Participants:11 healthy subjects and 10 post–superior labrum anteroposterior lesion patients (SLAP).Intervention:Contrasting markers were placed at the hip, elbow, and shoulder to represent shoulder elevation and were videotaped in 2 dimensions. Subjects performed 6 repetitions of active elevation (AE) and active assisted elevation of the shoulder, and 3 trials were analyzed using Datapac (comprehensive system) and Dartfish (basic system).Main Outcome Measures:Amplitudes and velocities of the shoulder angle were calculated. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and levels of agreement (LOA) were used to determine intersystem and intertrial reliability.Results:For AE, the amplitude maximum (ICC = .98–.99, SEM = 2–3°, LOA = −9° to 5°) and average velocity (ICC = .94–.97, SEM = 1°/s, LOA = −4° to 1°/s) indicated excellent intersystem reliability between systems. Intratrial reliability for minimum velocity was moderate for Datapac (ICC = .64, SEM = 4°/s, LOA = 7°/s) and poor for Dartfish (ICC = .52, SEM = 20°/s, LOA = 37°/s). Cohort results demonstrated for AE a greater amplitude for healthy v SLAP (139° ± 11° v 113° ± 13°; P = .001) and interaction for an average velocity increase of 2°/s in healthy and decrease of 2°/s in SLAP patients over the 3 trials (P = .02).Conclusions:Reliability ranges provide the means to assess the clinical meaningfulness of results. The cohort differences are supported when the values exceed the ranges of the SEM; hence the amplitude results are meaningful. For dynamic shoulder elevation measured using video, the assessment of velocity was found to produce moderate to good reliability. The results suggest that with these measures subtle changes in both measures may be possible with further investigations.

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