scholarly journals SPECTRAL TECHNIQUE FOR COMPLEX PROCESSING OF AEROSPACE MONITORING MULTISPECTRAL VIDEO DATA

2020 ◽  
Vol 259 (4) ◽  
pp. 19-24
Author(s):  
V. V. Vasilevsky
Keyword(s):  
Image Synthesis ◽  
Video Data ◽  
Adaptive Processing ◽  
Multispectral Images ◽  
Spatial Harmonic ◽  
Spectral Technique ◽  
Aerospace Monitoring ◽  
Complex Adaptive ◽  
Harmonic Components

The article studies the problem of increasing the efficiency of aerospace monitoring in identification of low-observable objects on the earth’s surface. The model of multispectral images based on spatial harmonic components is proposed. The article describes the algorithm of complex adaptive processing and image synthesis designed to improve identification of low-observable surface objects.

scholarly journals Development of a relay-vector control system for a multi-phase semiconductor converter of electric energy

2021 ◽  
pp. 5-15
Author(s):  
S. V. Panteleev ◽  
A. N. Malashin
Keyword(s):  
Mathematical Model ◽  
Vector Control ◽  
Electrical Energy ◽  
Control Action ◽  
Spatial Harmonic ◽  
Semiconductor Converter ◽  
Semiconductor Switch ◽  
Harmonic Components ◽  
Optimal Control Action ◽  
Vector Control System

A system of relay-vector control of current in the circuit of a polyphase electric machine has been developed. For this, on the basis of the analysis of electromagnetic processes in a multiphase semiconductor converter of electrical energy, its discrete mathematical model was created, which takes into account the redistribution of electromagnetic energy by individual spatial harmonic components, depending on the number of phases. Using this mathematical model, a method for relay control of spatial harmonic components of the input current of the converter in the “tube” has been developed. The formation of polyharmonic currents in each of the phases, conjugated in shape and phase with the voltage supplying the converter at each control period, is carried out by means of the optimal voltage vector of the semiconductor switch. To select the optimal control action, the objective function of the minimum deviation of the projections of the base voltage vectors of the semiconductor switch for the j-th combination of the state of the keys from the calculated control action determined by the mathematical model is used. An objective function of this type allows one to take into account different values of the amplitudes of the base voltage vectors of the semiconductor switch in the transformed orthogonal coordinate systems. In this case, there is no need to predict changes in the instantaneous values of the input current for one or two periods ahead, which is ensured by a decrease in the number of iterations to determine the optimal control action. To check the developed provisions, a simulation model of a nine-phase semiconductor converter of electrical energy with a relay vector control system was created. The results of the study of the model confirmed the adequacy of the developed technical solutions, the use of which will ensure the most complete realization of the own advantages of a multiphase electric machine in order to generally improve the weight, size and energy indicators of the autonomous power supply system.

scholarly journals WormPose: Image synthesis and convolutional networks for pose estimation in C. elegans

2021 ◽  
Vol 17 (4) ◽  
pp. e1008914
Author(s):  
Laetitia Hebert ◽  
Tosif Ahamed ◽  
Antonio C. Costa ◽  
Liam O’Shaughnessy ◽  
Greg J. Stephens
Keyword(s):  
Pose Estimation ◽  
Synthetic Data ◽  
Image Synthesis ◽  
Video Data ◽  
C Elegans ◽  
Convolutional Networks ◽  
Food Conditions ◽  
And Behavior ◽  
Nematode Worm ◽  
Imaging Conditions

An important model system for understanding genes, neurons and behavior, the nematode worm C. elegans naturally moves through a variety of complex postures, for which estimation from video data is challenging. We introduce an open-source Python package, WormPose, for 2D pose estimation in C. elegans, including self-occluded, coiled shapes. We leverage advances in machine vision afforded from convolutional neural networks and introduce a synthetic yet realistic generative model for images of worm posture, thus avoiding the need for human-labeled training. WormPose is effective and adaptable for imaging conditions across worm tracking efforts. We quantify pose estimation using synthetic data as well as N2 and mutant worms in on-food conditions. We further demonstrate WormPose by analyzing long (∼ 8 hour), fast-sampled (∼ 30 Hz) recordings of on-food N2 worms to provide a posture-scale analysis of roaming/dwelling behaviors.

scholarly journals Investigation of the Influence of Splitter Blades on the Resonance Conditions of Impellers

2019 ◽  
Vol 9 (10) ◽  
pp. 2051
Author(s):  
Kaicheng Liu ◽  
Cheng Yan
Keyword(s):  
Natural Frequency ◽  
Excitation Frequency ◽  
Specific Form ◽  
Lumped Parameter Model ◽  
Hazard Evaluation ◽  
Spatial Harmonic ◽  
Harmonic Response ◽  
Lumped Parameter ◽  
Engine Order ◽  
Harmonic Components

The conventional resonance conditions are derived based on the conventionally designed impellers without splitter blades. This paper proposes the resonance conditions for impellers under the excitation from the impeller–diffuser interaction with attention paid on the influence of splitter blades. A lumped parameter model is established and the modal analysis is carried out. The blade-based representative modal vector (RMV) is defined. The influence of splitter blades on the impeller’s traits of modes is investigated by analyzing the spatial harmonic contents of the RMV. Then, given the specific form of the diffuser-induced engine order excitation acting on the main and splitter blades, the resonance conditions are derived. Tuned and mistuned cases are provided for a practical impeller. The resonance conditions are verified by harmonic response calculations. The applications of the proposed resonance conditions in resonance identification and hazard evaluation of different excitations are given. The differences between the proposed resonance conditions and the conventional ones are discussed. The research indicates that even the RMV of the tuned impeller contains two harmonic components due to the existence of splitter blades. When the excitation frequency equals the natural frequency of the impeller and the excitation order matches with either harmonic index of the two harmonics, the resonance occurs. The results of case studies show that the harmfulness of various engine orders of excitation can be exactly evaluated by the joint use of the spatial harmonic contents analysis result and the proposed resonance conditions; however, analyzing based on the conventional resonance conditions may lead to the misjudgment of the harmfulness of the excitations.

scholarly journals Development of a vector control system of the semiconductor converter, which will provide a polyharmonic operating mode of a polyphase electric machine

2020 ◽  
Vol 65 (3) ◽  
pp. 332-340
Author(s):  
S. V. Panteleev ◽  
A. N. Malashin ◽  
A. E. Kaleda
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Vector Control ◽  
Electrical Energy ◽  
Operating Mode ◽  
Electric Machine ◽  
Spatial Harmonic ◽  
Semiconductor Converter ◽  
Harmonic Components ◽  
Vector Control System

A system for vector control of current in the circuit of a polyphase electric machine has been developed. For this, on the basis of the analysis of electromagnetic processes in a multiphase semiconductor converter of electrical energy, its discrete mathematical model was created, which takes into account the redistribution of electromagnetic energy by individual spatial harmonic components depending on the number of phases. Using this mathematical model and the scheme of injection of higher current harmonics, which provides a polyharmonic mode of operation of a semiconductor converter, a method for independent control of the spatial harmonic components of the input current of the converter has been developed. The formation in each of the phases of polyharmonic currents, conjugated in shape and phase with the voltage supplying the converter, is carried out by means of control actions in the form of voltage vectors of a semiconductor switch, the implementation of which is carried out by the method of multiphase space-vector modulation. To check the developed provisions, a simulation model of a nine-phase semiconductor converter of electrical energy with a vector control system was created. The results of the study of the model confirmed the adequacy of the developed technical solutions, the use of which will ensure the most complete realization of the own advantages of a multiphase electric machine in order to generally improve the weight, size and energy indicators of the autonomous power supply system.

scholarly journals WormPose: Image synthesis and convolutional networks for pose estimation in C. elegans

2020 ◽  
Author(s):  
Laetitia Hebert ◽  
Tosif Ahamed ◽  
Antonio C. Costa ◽  
Liam O’Shaugnessy ◽  
Greg J. Stephens
Keyword(s):  
Pose Estimation ◽  
Synthetic Data ◽  
Image Synthesis ◽  
Video Data ◽  
C Elegans ◽  
Convolutional Networks ◽  
Food Conditions ◽  
And Behavior ◽  
Nematode Worm ◽  
Imaging Conditions

An important model system for understanding genes, neurons and behavior, the nematode worm C. elegans naturally moves through a variety of complex postures, for which estimation from video data is challenging. We introduce an open-source Python package, WormPose, for 2D pose estimation in C. elegans, including self-occluded, coiled shapes. We leverage advances in machine vision afforded from convolutional neural networks and introduce a synthetic yet realistic generative model for images of worm posture, thus avoiding the need for human-labeled training. WormPose is effective and adaptable for imaging conditions across worm tracking efforts. We quantify pose estimation using synthetic data as well as N2 and mutant worms in on-food conditions. We further demonstrate WormPose by analyzing long (∼ 10 hour), fast-sampled (∼ 30 Hz) recordings of on-food N2 worms to provide a posture-scale analysis of roaming/dwelling behaviors.

scholarly journals ADAPTIVE MINIMAX ESTIMATION OF VIDEO-DATA IN AEROSPACE MONITORING APPLICATIONS

2020 ◽  
pp. 27-32
Author(s):  
V.V. Vasilevskiy
Keyword(s):  
Data Processing ◽  
Computational Algorithm ◽  
Adaptive Estimation ◽  
Video Data ◽  
Minimax Estimation ◽  
Model Parameters ◽  
Image Model ◽  
Minimax Estimate ◽  
Monitoring Applications ◽  
Aerospace Monitoring

This article is dedicated to the problem of increasing the performance of aerospace monitoring and automatic video-data processing under prior uncertainty. The development of adaptive minimax estimate for the image model parameters is proposed, and the computational algorithm for adaptive estimation of video-data is described.

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