scholarly journals Дослідження якісних показників поляризаційної селекції об’єктів на фоні пасивних завад в поляризаційно-доплерівській радіолокаційній системі

2021 ◽  
pp. 62-73
Author(s):  
Валерій Костянтинович Волосюк ◽  
Володимир Володимирович Павліков ◽  
Семен Сергійович Жила ◽  
Анатолій Владиславович Попов ◽  
Володимир Віталійович Кошарський ◽  
...  
Keyword(s):  
Optimal Algorithm ◽  
Internal Noise ◽  
Correlation Coefficients ◽  
Information Value ◽  
Residual Variance ◽  
Optimal Processing ◽  
Useful Signal ◽  
Input Signals ◽  
Passive Interference ◽  
Selection Of

The optimal algorithm of polarization-Doppler selection of targets against the background of passive interference is considered. The polarimetric properties of scattered electromagnetic radiation of objects. The functionally-determined mathematical model of the useful signal, structure and correlation characteristics of the internal radiation of the receiver is determined. The algorithm of optimal processing, synthesized within the method of maximum likelihood, is considered for two limit cases. Algorithmic actions in the processing of passive interference and methods of their compensation are considered and investigated. Based on the obtained results, the expression for the algorithm of compensation of interferences reflected from the earth's surface is written. The obtained algorithm equalizes the variance of the input signals and compensates the residual variance with the help of weight coefficients. On the basis of the developed algorithm the scheme of the structurally simplified optimum compensator of passive disturbances is formed. Feature processing of useful signals in the compensation scheme is investigated. To ensure the adaptability of the generated algorithm, the coefficient of the variance ratio is based on the results coming from the variance meter. It is proposed to introduce quality indicators of polarization object selection on the background of the underlying surface, which combines indicators of efficiency of passive interference compensation and indicators of efficiency of useful signal-processing against the background of internal noise of receivers. The corresponding dependence of the indicators on the correlation coefficients of passive interference of different polarizations, as well as on the coefficients that separately characterize the level of difference in signal intensities and interference in the reception channels. The information value of each indicator of the efficiency of polarization signal selection from the ratio of the input variances, the correlation coefficient of passive interference and the ratio of the input signals is investigated.The obtained results are proposed to be used to improve the quality of polarization selection of objects in ground-based and aerospace-based radar systems.

scholarly journals СИНТЕЗ ОПТИМАЛЬНОГО АЛГОРИТМУ ПОЛЯРИЗАЦІЙНОЇ СЕЛЕКЦІЇ КОРИСНИХ СИГНАЛІВ НА ФОНІ ПАСИВНИХ ЗАВАД В РАДАРІ З СИНТЕЗУВАННЯМ АПЕРТУРИ

2020 ◽  
pp. 109-115
Author(s):  
Валерій Костянтинович Волосюк ◽  
Володимир Володимирович Павліков ◽  
Семен Сергійович Жила ◽  
Микола Вікторович Руженцев ◽  
Володимир Віталійович Кошарський ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Background Radiation ◽  
Optimal Algorithm ◽  
Underlying Surface ◽  
Matched Filtering ◽  
Antenna Aperture ◽  
External Interference ◽  
Useful Signal ◽  
Passive Interference ◽  
Selection Of

Using the method of maximum likelihood, the optimal algorithm of polarization selection of objects on the background of the underlying surface, hydrometeors, urban buildings from aerospace carriers of radio electronic equipment has been synthesized. To solve the problem polarimetric properties of the scattered electromagnetic radiation of different natural environments and anthropogenic objects were analyzed. Has been determined the functional-determined mathematical model of the useful signal, the structure and correlation characteristics of scattered background radiation and white noise inside the multichannel receiver. It is assumed that the wanted signals are measured with phase accuracy in a coherent receiver. When solving the optimization problem, the method of the maximum likelihood functional and the likelihood functional for correlated processes were used, contains the inverse matrix of inverse correlation functions of the observation equation. The obtained signal processing algorithm, in addition to the classical operations of accumulating the trajectory signal with the preservation of the phase structure and its matched filtering, provides for polarization and frequency selection in the line of decorrelation filters. In the case when the internal noise is very small in comparison with external interference and the correlation between the channels of vertical and horizontal polarization approaches unity, almost complete compensation of passive interference occurs. Further spectral rejection of the reflected signals is practically unnecessary and it is possible to restrict ourselves only to matched filtering of the useful signal. In the absence of background radiation correlation, the channels for receiving oscillations of different polarizations become independent and the main operation for the selection of useful signals is spectral rejection of passive interference and matched filtering of the useful signal. The developed algorithm can be implement in cognitive radars due to its adaptability to the parameters of background radiation in accordance with the change in the scattering covariance matrix of the underlying surface. Based on the results obtained, a block diagram of a multichannel polarization radar with synthesized antenna aperture has been developed.

scholarly journals Оптимізація поляризаційно-доплерівської селекції малорозмірних об’єктів на тлі підстильної поверхні

2021 ◽  
pp. 49-61
Author(s):  
Валерій Костянтинович Волосюк ◽  
Володимир Володимирович Павліков ◽  
Семен Сергійович Жила ◽  
Анатолій Владиславович Попов ◽  
Володимир Віталійович Кошарський ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Optimal Algorithm ◽  
Block Diagram ◽  
Internal Noise ◽  
Underlying Surface ◽  
Natural Environments ◽  
Signal Processing Algorithm ◽  
Method Of Maximum Likelihood ◽  
Passive Interference ◽  
Selection Of

Using the method of maximum likelihood, the optimal algorithm of polarization-Doppler selection of objects on the background of the underlying surface, hydrometeors, urban buildings from aerospace carriers of radio electronic equipment has been synthesized. To solve the problem polarimetric properties of the scattered electromagnetic radiation of natural environments and anthropogenic objects were analyzed.The functional-deterministic mathematical model of the useful signalis determined. When solving the optimization problem, the method of maximum likelihood functionality and likelihood functionality for correlated processes were used, which contains the inverse matrix of inverse correlation functions of the observation equation. The obtained signal processing algorithm includes operations of spectral resection of passive interference. Polarization compensation of passive interference is performed by a combination of interchannel subtraction of the reflected signals of different polarizations. The quasi-optimal features of the synthesized algorithm, which has an obvious physical value and is optimal in the absence of internal noise, are considered. Based on the obtained results, a block diagram of the polarization-Doppler noise compensator and selection of useful signals against the background of noise reflections from the earth's surface has been developed. The study of the physical characteristics of the elements of the polarization covariance matrix of interferences at a high level of correlation of reflections of passive interferences of different polarizations is conducted.Based on the obtained results, it is proposed to introduce indicators of efficiency of passive interference compensation and selection of useful signals. The results of the analysis of the obtained indicators depending on the coefficient of the ratio of variances of passive interference indicate the need to use the polarization differences between signals and interference for selecting objects against the background of the underlying surface. The results obtained can be used to create ground-based and aerospace-based radar systems for detecting moving objects and objects with pronounced polarization features.

IMPROVEMENT OF SPRING DURUM WHEAT SELECTION METHODOLOGIES UNDER CLIMATE CHANGE CONDITIONS

1970 ◽  
pp. 33-36
Author(s):  
А. I. Grabovets ◽  
V. P. Kadushkina ◽  
S. А. Kovalenko
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Correlation Coefficient ◽  
Harvest Index ◽  
Unit Area ◽  
Correlation Coefficients ◽  
Chemical Mutagenesis ◽  
Main Method ◽  
The Relationship ◽  
Selection Of

With the growing aridity of the climate on the Don, it became necessary to improve the methodology for conducting the  breeding of spring durum wheat. The main method of obtaining the source material remains intraspecific step hybridization. Crossings were performed between genetically distant forms, differing in origin and required traits and properties. The use of chemical mutagenesis was a productive way to change the heredity of genotypes in terms of drought tolerance. When breeding for productivity, both in dry years of research and in favorable years, the most objective markers were identified — the size of the aerial mass, the mass of grain per plant, spike, and harvest index. The magnitude of the correlation coefficients between the yield per unit area and the elements of its structure is established. It was most closely associated with them in dry years, while in wet years it decreased. Power the correlation of the characteristics of the pair - the grain yield per square meter - the aboveground biomass averaged r = 0.73, and in dry years it was higher (0.91) than in favorable ones (0.61 - 0.70) , between the harvest and the harvest index - r = 0.81 (on average). In dry years, the correlation coefficient increased to 0.92. Research data confirms the greatest importance of the mass of grain from one ear and the plant in the formation of grain yield per unit area in both dry and wet years. In dry years, the correlation coefficient between yield and grain mass per plant was on average r = 0.80; in favorable years, r = 0.69. The relationship between yield and grain mass from the ear was greater — r = 0.84 and r = 0.82, respectively. Consequently, the breeding significance of the aboveground mass and the productivity of the ear, as a criterion for the selection of the crop, especially increases in the dry years. They were basic in the selection.

Cascade control of «smart home» heating

2022 ◽  
Vol 14 (4) ◽  
pp. 82-89
Author(s):  
Sergey Polyakov ◽  
V. Akimov ◽  
A. Polukazakov
Keyword(s):  
Structural Changes ◽  
Experimental Studies ◽  
Residential Building ◽  
Heating System ◽  
Cascade Control ◽  
Virtual Object ◽  
Coolant Temperature ◽  
Home Heating ◽  
Input Signals ◽  
Selection Of

The article discusses the issues of implementing the conversion of input signals of «smart» sensors for automation of the heating system, an algorithm for calculating the parameters of measuring circuits with a nonlinear element and an operational amplifier is developed. The issues of modeling cascade control of residential building heating systems are investigated. The results of the analysis and selection of parameters of the cascade control system are presented. An algorithm implementing the operation of a virtual object is given. The structures of management of residential building objects are proposed. The method of calculating the adjustment of the controller for cascade control is given. For the heating system stand, the procedure for setting the parameters of the process of PID control of the coolant temperature is considered. The results confirming the achievability of the proposed structural changes are obtained. The results of experimental studies are presented.

“Red” and “green” flags of risk disclosures – identifying associations between positive and negative key phrases and consecutive cumulative abnormal stock returns

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Deborah Yvonne Nagel ◽  
Stephan Fuhrmann ◽  
Thomas W. Guenther
Keyword(s):  
Stock Returns ◽  
Relevant Information ◽  
Risk Information ◽  
Information Value ◽  
Research Approach ◽  
Content Type ◽  
Abnormal Stock Returns ◽  
Key Phrases ◽  
Risk Disclosures ◽  
Selection Of

Purpose The usefulness of risk disclosures (RDs) to support equity investors’ investment decisions is highly discussed. As prior research criticizes the extensive aggregation of risk information in existing empirical research, this paper aims to provide an attempt to identify disaggregated risk information associated with cumulative abnormal stock returns (CARs). Design/methodology/approach The sample consists of 2,558 RDs of companies listed in the S&P 500 index. The RDs were filed within 10 K filings between 2011 and 2017. First, this study automatically extracted 35,685 key phrases that occurred in a maximum of 1.5% of the RDs. Second, this study performed stepwise regressions of these key phrases and identified 67 (78) key phrases that show positive (negative) associations with CARs. Findings The paper finds that investors seem to value most the more common key phrases just below the 1.5% rarest key phrase threshold and business-related key phrases from RDs. Furthermore, investors seem to perceive key phrases that contain words indicating uncertainty (impacts) as a negative (positive) rather than a positive (negative) signal. Research limitations/implications The research approach faces limitations mainly due to the selection of the included key phrases, the focus on CARs and the methodological choice of the stepwise regression analysis. Originality/value The study reveals the potential for companies to increase the information value of their RDs for equity investors by providing tailored information within RDs instead of universal phrases. In addition, the research indicates that the tailored RDs encouraged by the SEC contain relevant information for investors. Furthermore, the results may guide the attention of equity investors to relevant text passages whose deeper analysis might be useful with regard to investors’ capital market decisions.

Input Vector Identification and System Model Construction by Average Mutual Information

2000 ◽  
Author(s):  
Paul B. Deignan ◽  
Peter H. Meckl ◽  
Matthew A. Franchek ◽  
Salim A. Jaliwala ◽  
George G. Zhu
Keyword(s):  
Mutual Information ◽  
System Model ◽  
Input Output ◽  
Output Data ◽  
Average Mutual Information ◽  
Virtual Sensors ◽  
Input Signals ◽  
Model Independent ◽  
Intelligent Model ◽  
Selection Of

Abstract A methodology for the intelligent, model-independent selection of an appropriate set of input signals for the system identification of an unknown process is demonstrated. In modeling this process, it is shown that the terms of a simple nonlinear polynomial model may also be determined through the analysis of the average mutual information between inputs and the output. Average mutual information can be thought of as a nonlinear correlation coefficient and can be calculated from input/output data alone. The methodology described here is especially applicable to the development of virtual sensors.

scholarly journals Selection of a suitable data set and model for the genetic evaluation of the linear description of conformation and type description in Old Kladruber horses

2012 ◽  
Vol 55 (2) ◽  
pp. 105-112
Author(s):  
L. Vostrý ◽  
K. Mach ◽  
J. Přibyl
Keyword(s):  
Random Effects ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Suitable Model ◽  
Residual Variance ◽  
Linear Type ◽  
Colour Variant ◽  
Repeated Evaluation ◽  
Estimation Of Genetic Parameters ◽  
Selection Of

Abstract. The objective of this paper was to select a suitable data subset and statistical model for the estimation of genetic parameters for 36 traits of the linear type in 977 Old Kladruber horses. Two subsets were tested to identify a suitable subset for analysis. One subset included repeated evaluation of certain individuals, whereas the other did not. The most suitable subset included repeated evaluation (n=1 390). The selection of a suitable model was made from 4 candidate models. These models comprised a number of random effects (direct individual effect and animal permanent environmental effect of the animal) and a number of fixed effects (colour variant, stud, colour variant × stud interaction, sex, age at description, year of birth, year of description). The model was selected based on the Akaike information criterion (AIC, Akaike 1974), residual variance and heritability coefficient. The model that included colour variant, stud, colour variant × stud interaction, sex, age at description, and year of description as fixed effects and direct individual and animal permanent environment as random effects was the most suitable model for the estimation of genetic parameters and for the subsequent estimation of breeding values.

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