St. Petersburg State University of Telecommunications

About: St. Petersburg State University of Telecommunications is a education organization based out in Saint Petersburg, Russia. It is known for research contribution in the topics: Computer science & The Internet. The organization has 408 authors who have published 465 publications receiving 2160 citations.

Algorithms for Multiple Signals Adaptive Processing in Radio Engineering Systems Antenna Arrays

Abstract: Tasks of adaptive algorithms synthesis in antenna arrays for the individual and group adaptive signal processing implementation to improve the quality of multiple signals reception in radio engineering systems are considered. A mathematical description of the procedures for individual and group adaptive signal processing is given, as well as formulas for calculating the optimal weight vector that provides the best approximation of the input signal to the desired signal. Approximate methods of optimal signal processing based on iterative algorithms in the form of Widrow gradient adaptation algorithms are considered. The modeling of gradient algorithms in the MATLAB environment has been carried out. Based on the simulation results, an analysis of the gradient algorithms sensitivity for changes in initial conditions, such as the convergence step of the algorithm, the number of antenna array elements, and SNR was carried out. The optimal values of the convergence step have been obtained based on the analysis of the algorithm's sensitivity and the convergence rate of the algorithms. In conclusion, an example of an antenna array radiation pattern, which provides adaptive signal processing, taking into account the optimal parameters of the system, is given.

Information agent reaction analysis method under the influence of information and communication environment

Abstract: A perspective direction of development of information infrastructures is allocated. The main feature of the complex approach to the intellectualization of information infrastructures is presented. The key tasks of the model-analytical intelligence of information agents are described. The expediency of developing a method for analyzing reactive actions of an agent under the influence of an infocommunication environment is substantiated. The class of query models of intelligent information agents is selected. The characteristics of extended object-oriented query models are considered. A new method has been developed for the formation of the model-analytical intelligence of information agents under the influence of the infocommunication environment. The sequence and content of the basic operations of the new method are revealed. The advantages of the proposed method are determined.

Мр-морфометрия и диффузионно-тензорная мрт в оценке изменений мозолистого тела у детей со спастической диплегией

Abstract: The aim of the study was to compare the volumes according to MR morphometry and diffusion values according to diffusion-tensor MRI (DT-MRI) of the corpus callosum in children with spastic diplegia. Methods : the main group consisted of 12 children aged from 1 year 8 months to 4 years 3 months, the comparison group — 5 children with normal motor development, who did not have motor impairments, at the age from 1 year and 3 months up to 3 years 8 months. All patients underwent MR-morphometry, DTI. A comparison was made between the volumes and diffusion values of the corpus callosum between groups. Results : Significant differences were found (p<0,05) in the volume of the genu, splenium and the middle third of the trunk of the corpus callosum. Significant differences (p<0,05) of diffusion values in the middle and posterior third of the trunk of the corpus callosum were also revealed. The data obtained demonstrate the diffuse nature of pathological changes in the corpus callosum in children with spastic diplegia.

Adaptation of Psychoacoustic analysis to wavelet domain in lossy audio coding

Abstract: The paper presents the authors' current research in adaptation of the MPEG AAC Psychoacoustic Model to the Discrete Wavelet Packet coding algorithm. We discovered the complex distribution of wavelet quantization noise across the audio spectrum due to significant cross-band aliasing. We also obtained the wavelet quantization noise function related to the analysis bands of MPEG AAC Psychoacoustic Model. The described approach provided the quantization matrix, which can be used for exact estimation of overall quantization noise during lossy coding.

Analysis of Options of Cooperative Processing of Measurements in Long-Range Multistatic Radar System

Abstract: Background/Objectives: The study considers the options of cooperative processing of long-range measurements in multistatic radio-technical systems. The information on the sum of distances improves the precision of the estimated range. Method: The investigations employ simulation and statistical models describing the techniques of cooperative processing of the radar information for the case of three-station radio-technical system. Findings: The calculated range values include all measurements obtained by the multistatic system with their relevant weights. The investigations show the effects produced by the selected number of stations and by the precision of the original measurements on the formation of the resulting estimations under the conditions of different initial data that help achieve the preset precision within shorter intervals without the limitations of the object movement hypothesis. The new results of this study are represented by the equations that describe the slant distances in the course of cooperative processing of measurements with different types of the correlation matrix of the errors and for different options of data processing. It has been proven that the suggested option of measurement processing possesses high informational stability against any anomalous measurements. Applications/Improvements: The results of this study will be helpful for upgrading the existing radio navigation systems and for developing justified requirements to any prospective research studies in this area of investigation.