Choosing Damping Parameters for the Inertial Orientation System

The article discusses criteria for selecting the vibration protection for the spacecraft inertial orientation system. The considered vibration protection system allows providing acceptable amplitude acceleration for the gyroscopic device sensitive elements under vibration impact on the device body during the spacecraft launching and high angular stability of the position of the sensitive elements relative to the inertial coordinate system during a long period of operation (15 years) in orbit. The proposed vibration protection system consists of shock absorbers (springs) with stable high elastic characteristics under all factors of operation in the outer space and dynamic vibration dampers. The article presents a method for determining the parameters of dynamic vibration dampers taking into account the characteristics of the shock absorber, critical for the damping system of an inertial device. The proposed method for adjusting dynamic vibration dampers consists in suppressing vibrations at the natural frequency f1 of the shock absorption system and providing acceptable values of the gain coefficients of the structure resonant vibration amplitudes near the natural frequency f1. Certain characteristics of the damping system allow realizing the permissible vibration amplification coefficients at resonance, without significantly affecting the level of vibration suppression in the natural frequency zone of the vibration protection object

Analysis of Interferometer with Micro-Mirror on Beam Splitting Cube

The control of the shape of the optical part surface by the interference method has become an integral part of the process of their shaping. With a precisely focused interferometer interferometry allows obtaining an interference pattern similar to a topographic map of the error profile of the wave surface under investigation. The interferometer must form a map of the optical surface with high accuracy --- the permissible distortion of the interference fringe caused by an interferometer error should not exceed 0.1 of the distortion value caused by an error on the examined surface. The dependence of the interference pattern formation on the errors in the arrangement of the interferometer components, i.e., defocusing, was theoretically analyzed using Fourier transforms. The analysis was performed for an interferometer containing a laser illuminator, a concave spherical mirror with a central hole, coaxial to the illuminator, and a beamsplitting element in the form of a cube-prism with a semitransparent hypotenuse face. On the first flat face of the cube-prism, a microspherical concave mirror is made with the center located on the optical axis of the interferometer. A method for calculating the defocusing of a controlled spherical mirror and the corresponding wave aberration of the working wavefront is presented. An example of calculating the design parameters of the interferometer and the permissible defocusing of the controlled spherical mirror is given

Finding Errors in Programs for Processing Graphic Images using the Fuzzing Method

Increasing number of software for automated graphics processing requires effective testing methods. One of these methods is fuzzing, for which it is necessary to determine the most effective algorithms for creating test data in order to increase the number of errors found and minimize hardware resources. The comparison of algorithms for creating test data for finding errors in the executable code of programs designed for processing graphic images is the result of the performed research. Using Bayesian networks to describe fuzzing allows determining the relationships between structural components during testing. Based on the results of the comparison of fuzzing algorithms for creating test data, the most effective algorithms for finding errors in the executable code of programs for processing graphic images have been identified. The performance of the proposed algorithms was tested on a number of existing vulnerabilities classified as CVE (Common Vulnerabilities and Exposures). The processing of the results of experiments on the creation of test data was carried out using the simulation environment, allowing analyzing the testing process step by step. The obtained research results, algorithms for creating test data for finding errors can be used at various stages of software testing

Developing an Algorithm for Determining Malfunctions in the Measuring Channels of the Acoustic Leak Control System

Nowadays Russian and foreign NPP operate systems for monitoring coolant leakage at the primary circuit based on measuring the dispersion of generated acoustic signals (acoustic waves) propagating over the metal surface. In the acoustic leak monitoring systems provision are made to self-diagnosis of measuring channels, as well as an adaptive algorithm is applied that allows automatic readjusting to the use of neighboring measuring channels instead of those that have failed. At the same time, there may be such malfunctions in the system technical means that do not automatically diagnose the malfunction of the measuring channels, which may lead to the failure of the system function to determine the magnitude and coordinate of the leak of the primary circuit coolant. That is why, the task of developing algorithms for determining the malfunction of the measuring channels of the acoustic leak monitoring system, implemented using software without making changes to the technical means of the system, is urgent. An algorithm is proposed for determining the malfunction of the measuring channels of the acoustic leak control system using a test signal of increased duration. An analysis of the applicability of the algorithm was performed on a representative sample of signals from measuring channels of the acoustic leak monitoring system of campaign 2018--2019 Novovoronezh NPP-2 рower Unit no. 1. The proposed algorithm has been implemented in the testing mode at power Unit no. 1 of Novovoronezh NPP-2 since the start of a new campaign in July 2019

Algorithm of a Device Designed to Support Decision Making to Counter the Threat of an Aviation Accident

An algorithm for countering the threat of an aviation accident is proposed. It is realized in a decision-making support device, which is the main element of the aircraft flight safety control system and appears to be a dynamic expert system. A feature of the proposed device is generation of recommendations to a pilot to get out of an aviation accident upon identifying significant variation in time of the input variables affecting the aircraft flight safety based on information about psychophysical state of the pilot, technical conditions of the control object, external influencing factors, as well as forecast of alterations in the flight conditions. A corresponding block diagram is provided to describe the aircraft flight safety control system. An algorithm to support decision making by the crew is constructed making it possible to generate recommendations for the pilot and signals to the control system to increase the aircraft safety level. The set of decision-making support rules is evaluated for completeness and absence of data inconsistency. Numerical simulation of the algorithm operation accompanied by evaluation of the set of decision-making support rules confirmed its operating capability. Results obtained could be introduced in development of the aircraft flight safety control systems

Analysis of Supercritical Stability of Distributed Real-Time Information Systems

The article describes an approach to the numerical analysis of the stability of distributed information systems under a load that varies over time allowing for a short-term load exceeding critical values. Information systems are considered as imperfect queuing systems in which the intensity of the message flow may depend on the size of the queues of applications. Based on this approach, criteria for the stable and unstable behavior of the system under load are formulated, where the stable behavior of the system is understood as the ability of the system to return to its normal mode of operation independently when the external load drops below the critical value, and unstable one when there is the transition to an emergency state. As examples, the most common types of unstable systems are considered, as well as an example of a distributed system that implements a complex queuing system, which, depending on the characteristics of the service, can be either stable or unstable. The analysis of such a system is carried out, which is confirmed by the results of numerical simulation. Based on the analysis results, zones of stability and instability are determined. Features of the implementation of distributed real-time information systems are considered, practical recommendations for the implementation of sustainable information systems are given

Virtual Reality Mobile Platform for Restoring Upper Limbs Functions using Electromiography Data

The article describes a mobile virtual reality platform based on the biological feedback of electromyography for restoring the functions of the upper limbs of people affected by accidents, stroke, Parkinson's disease or who suffered as a result of military operations. The definition of the electromyography (EMG) signal is given. The effectiveness of the biological feedback method in the rehabilitation process is indicated. The problem of initial data preprocessing is considered in order to identify the informative features of the EMG signal in the time domain. The general scheme of a mobile virtual reality platform based on biological feedback is described and preliminary evidence of the platform capability in its current state is presented. The block diagram of the EMG data acquisition module is developed. Developing a training program within the framework of computer games in two-dimensional or three-dimensional space is proposed. The algorithm of the mobile virtual reality platform based on the biological feedback of electromyography is illustrated. The results of the implementation of the proposed biofeedback electromyography system are presented. The advantages of the developed system in comparison with other systems currently available are emphasized; the disadvantages of this method are identified and ways to eliminate them are proposed

Non-Destructive Method in Determining the Barley Grain Vitreousity

Possibilities of non-destructive express-evaluation of the barley grain vitreousity using machine vision and digital image processing methods were studied. The study was carried out with the proprietary design hardware and software complex on barley samples of three different varieties provided by the LLC "Nosters". Transmittance in the near IR wavelength range was used as the objective criterion in classifying grains as vitreous, partially vitreous and better use powdery. Classification group boundaries were determined empirically by the cross-section inspection method. The optimal filming mode was experimentally selected, and the algorithm for digital processing of grain images was developed in order to determine the number of better use powdery grains in a sample. In addition to classifying grains by vitreousity, the proposed approach also makes it possible to evaluate uniformity of a sample by this indicator and, thus, to identify a grain of higher quality. It was found out that grain orientation introduces an error of not more than 5 %, and high repeatability of the results and, as a consequence, accuracy of the algorithm are characterized by the variation coefficient of 1.1 %

Calculation of Equilibrium Composition of Complex Thermodynamic Systems using Julia Language and Ipopt Library

The article considers the possibility of using the Ipopt optimization package for the calculating the phase and equilibrium compositions of a multicomponent heterogeneous thermodynamic system. Two functions are presented for calculating the equilibrium composition and properties of complex thermodynamic systems, written in the Julia programming language. These functions are the key ones in the program integrated with the IVTANTERMO database on thermodynamic properties of individual substances and used for conducting test calculations. The test calculations showed that Ipopt package allows determining the phase and chemical compositions of simple and complex thermodynamic systems with a fairly high speed. Using the JuMP modeling language significantly simplifies the preparation of the initial data for the Ipopt package, therefore the functions presented in this article are very compact. It is shown how the Ipopt package can be used when the temperature of the thermodynamic system is unknown. The approach proposed in this work is applicable both for analyzing the equilibrium of individual chemical reactions and for calculating the equilibrium composition of complex chemically reacting systems. The simplicity of the proposed functions allows their easy integrating into application programs, embedding them into more complex applications, using them in combination with more complex models (real gas, nonideal solutions, constrained equilibria), and, if necessary, modifying them. It should be noted that the versatility of the JuMP modeling language makes it possible to replace the Ipopt package with another one without significant modification of the program text

Classification of Weld Defects Based on Convolution Neural Network

Automatic welding technology has been widely applied in many industrial fields. It is a complex process with many nonlinear parameters and noise factors affecting weld quality. Therefore, it is necessary to inspect and evaluate the quality of the weld seam during welding process. However, in practice there are many types of welding seam defects, causes and the method of corrections are also different. Therefore, welding seam defects need to be classified to determine the optimal solution for the control process with the best quality. Previously, the welder used his experience to classify visually, or some studies proposed visual classification with image processing algorithms and machine learning. However, it requires a lot of time and accuracy is not high. The paper proposes a convolutional neural network structure to classify images of welding seam defects from automatic welding machines on pipes. Based on comparison with the classification results of some deep machine learning networks such as VGG16, Alexnet, Resnet-50, it shows that the classification accuracy is 99.46 %. Experimental results show that the structure of convolutional neural network is proposed to classify images of weld seam defects have availability and applicability