scholarly journals STATISTICAL CHARACTERISTICS OF THE ENERGY-CONCEALED PHASE-MANIPULATED SIGNAL

2019 ◽  
pp. 108-115
Author(s):  
S. O. Kovtun ◽  
S. V. Kovalchuk ◽  
P. P. Topolnytsky
Keyword(s):  
Density Distribution ◽  
Probability Density ◽  
Input Signal ◽  
Detection Threshold ◽  
Probability Density Distribution ◽  
Signal Noise ◽  
Output Effect ◽  
Useful Signal ◽  
Noise Ratio ◽  
The Given

The law of distribution of the output effect differs from the normal one at the output of the receiving path realized on the basis of autocorrelation algorithm with quadrature processing. When there is no signal at the input of the receiver, the distribution of the output effect corresponds to Rayleigh’s or Rayleigh – Rice’s law in condition of its presence. The probability density distribution at the output of an incoherent auto correlation receiver with quadrature processing is considered in relation to the input level of the energy-concealed phase-manipulated signal. In order to detect a useful signal it is necessary that, at the output of the receiver, the signal / noise ratio exceeds the detection threshold determined by the Neumann – Pearson criterion according to the given probability of false alarm. The level of the signal-to-noise ratio at the output of an incoherent autocorrelation receiver with quadrature processing has been calculated. A characteristic feature of the presented graphs is the linear dependence of the output signal / noise ratio relative to the input signal. This feature is observed in the input signal / noise ratio which is less than one. The curves for the distribution of the probability density of the input signal mix and noise corresponding to the generalized Rayleigh’s law (Rayleigh-Rice) are constructed in the book. There is a shift of curves for the abscissa axis according to the given probabilities of false alarms and accumulation time (observation). It is evident from the given graphs that the offset of the abscissa of the input signal value / noise ratio significantly depends on the accumulation of the input mixture time. The curves for detecting an energy-concealed phase-manipulated signal by a non-coherent autocorrelation receiver with quadrature processing on the basis of the probability density distribution are obtained. The results of the calculations indicate that detection of a phase-manipulated signal on the background of "white" noise is possible in case of an input-to-noise ratio of less than one, that is, up to -32 dB in real time (up to 0.1 s).

scholarly journals Influence Assessment of the Information Concerning the Bearing Type of Axle Box of Cars on the Automatic Classification Accuracy of Heated Boxes

2021 ◽  
pp. 5-14
Author(s):  
V. V Burchenkov
Keyword(s):  
Density Distribution ◽  
Probability Density ◽  
Heating Temperature ◽  
Threshold Value ◽  
Probability Density Distribution ◽  
Practical Implementation ◽  
System Of Equations ◽  
Average Value ◽  
Optimal Thresholds ◽  
Different Types

Purpose. The main purpose of the work is to determine and classify the heated cars’ boxes based on the probability of appearance of roller and cassette type boxes in the classes of heated and overheated boxes, as well as the laws of probability density distribution of the recognition signs of normally heated and overheated roller and cassette type boxes. Methodology. The operation features of freight cars with cassette type axle boxes with increased operating heating have been investigated. The methodology of assessing the probability of recognition errors was proposed, which takes into account the fact that sets of normally heated and overheated boxes consist of subsets of boxes with different types of bearings. A system of equations is obtained, the roots of which represent еру values that minimize the recognition probability of the errors of the heated boxes. Findings. It was found out that with some methods of determining the bearing type, for example, by the average value of the ranges of thermal image for each car, the probability of erroneous selection may depend on the probability density distribution of the sign for bearings of different types and the threshold value of this sign. The optimal thresholds for detecting the overheated roller boxes in comparison with the optimal thresholds for detecting overheated cassette boxes were determined. It has been established that the pass of an overheated cassette bearing, provided that the type of bearing is determined correctly, is less likely to lead to an accident than if the cassette box is classified as a roller box. The rejection criteria of axle boxes according to their heating temperature difference on one of the wheel set axis for three variants of settings of the alarm system according to an arrangement of multipurpose complexes of technical means (CTM) were formulated. The practical implementation of this method of adjusting the CTM settings for the Minsk branch of the Belarusian Railways was demonstrated. Originality. A system of equations is obtained, which allows finding the optimal values of temperature thresholds for the detection of overheated roller and cassette boxes under the assumption that the error probabilities in the selection of boxes by their types are known and constant. Practical value. The developed method of adjusting the alarm settings of CTM makes it possible to significantly reduce unjustified train delays and the number of car uncouplings.

scholarly journals A New Modeling Approach for the Probability Density Distribution Function of Wind power Fluctuation

2019 ◽  
Vol 11 (19) ◽  
pp. 5512 ◽  
Author(s):  
Lingzhi Wang ◽  
Jun Liu ◽  
Fucai Qian
Keyword(s):  
Distribution Function ◽  
Density Distribution ◽  
Probability Density ◽  
Wind Power ◽  
Rapid Development ◽  
Probability Density Distribution ◽  
Power Fluctuation ◽  
Function Model ◽  
New Model ◽  
Fireworks Algorithm

With the rapid development of grid-connected wind power, analysing and describing the probability density distribution characteristics of wind power fluctuation has always been a hot and difficult problem in the wind power field. In traditional methods, a single distribution function model is used to fit the probability density distribution of wind power output fluctuation; however, the results are unsatisfying. Therefore, a new distribution function model is proposed in this work for fitting the probability density distribution to replace a single distribution function model. In form, the new model includes only four parameters which make it easier to implement. Four statistical index models are used to evaluate the distribution function fits with the measured probability data. Simulations are designed to compare the new model with the Gaussian mixture model, and results illustrate the effectiveness and advantages of the newly developed model in fitting the wind power fluctuation probability density distribution. Besides, the fireworks algorithm is adopted for determining the optimal parameters in the distribution function model. The comparison experiments of the fireworks algorithm with the particle swarm optimization (PSO) algorithm and the genetic algorithm (GA) are carried out, which shows that the fireworks algorithm has faster convergence speed and higher accuracy than the two common intelligent algorithms, so it is useful for optimizing parameters in power systems.

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