Summaries of the Issue


The results of a study of the optical properties of thin films based on indium tin oxides (ITO) with single-walled carbon nanotubes are presented. ITO thin films were deposited onto K8 crown glass substrates using laser-oriented deposition. Using the same method, single-walled carbon nanotubes were deposited onto the ITO surface. To vary the parameters of the interface, the average electric field strength in the range of 100–600 V/cm was adjusted during the deposition process. Identification of the structures was carried out by ellipsometry in the spectral range of 200–800 nm. To interpret the ellipsometry results of ITO thin films on K8 crown glass substrates, the Cauchy (for substrates) and Lorentz (for ITO) models were used together. The ITO–carbon nanotubes interface analysis was carried out by effective medium approximation and the Lorentz model using several oscillators. It has been shown, that in laser-oriented deposition of carbon nanotubes onto the surface of ITO thin films, according to the effective medium approximation, the thickness of the carbon nanotubes-ITO interface varies in the range of 23–36 nm with the percentage of carbon nanotubes in the range of 30–64 % at the interface. The increase in these parameters correlates with an increase in the average electric field strength during the deposition of carbon nanotubes. In accordance with the Lorentz model, a long-wavelength shift of the extinction coefficient peaks and a decrease in the refractive index of the interface in the visible region are observed. This phenomenon is caused by the implantation of carbon nanotubes into ITO. As the electric field strength increases, the contribution of laser-deposited carbon nanotubes to the ITO–carbon nanotubes interface increases, which is accompanied by a decrease in the refractive index in the visible region and a long-wavelength shift of the extinction coefficient peaks. The data obtained indicate the formation of a composite structure based on ITO with carbon nanotubes, the optical properties of which can be controlled by the average electric field strength during the laser-oriented deposition. These structures can be used in the design of optical electronics elements problems in cases where optical matching with adjacent functional layers is necessary. 
The paper examines the xanthene fluorescent dyes questions available to a wide laboratories range in order to detect microplastics with an average particle length of 157 ± 59 μm in soil samples and conduct phytotests using fluorescently labeled microplastics. For the research, soils with a humus content of 1.59 ± 0.15 % (P1) and 6.74 ± 0.11 % (P2) as well as suspension polyvinyl chloride (RusVinyl LLC, 157 ± 59 μm, white) were used. In order to study the possibility of selective staining of microplastics in the presence of soil particles, polyvinyl chloride microparticles, soil P1 and P2, as well as a mixture of soil P1 and polyvinyl chloride (5 % by weight) were stained with rhodamine B, rhodamine G, fluorescein and eosin Y in isopropyl alcohol (dye concentration — 200 mg/L, temperature — 100 °C, staining time — 2 hours with constant stirring on a magnetic stirrer) and washed with distilled water on a paper filter. To study the chemical polyvinyl chloride microparticles structure before and after staining attenuated total reflectance-Fourier transform infrared spectroscopy was used (spectrometer Tensor 37 (Bruker, Germany), attenuated total internal reflection MIRacle Pike attachment with a diamond-coated ZnSe crystal). Spectrophotometry and microphotograph analysis using ImageJ software were used to determine whether dye could be leached from polyvinyl chloride microparticles after repeated washing with water. To conduct the laboratory experiment to detect microplastics in soil a mixture of P1 soil and polyvinyl chloride microparticles (0.1 % by weight) was prepared and stained with rhodamine G. In order to reduce the amount of mineral particles and concentrate polyvinyl chloride microparticles, a separation technique was used due to the difference in density using binary solution of NaCl and Ca(NO3)2. Microphotographs were obtained using an optical microscope with an additional ultraviolet source (λ = 365 nm). Image areas measurements of detected microparticles projections, that are necessary for calculating the approximate mass of the pollutant, were carried out using ImageJ software. The possibility of using fluorescently labeled polyvinyl chloride microparticles for phytotests was established using the seed germination test in contaminated soil and studying seedlings using an optical microscope with an additional ultraviolet source. It was shown that after staining with rhodamine B and rhodamine G, fluorescence is observed in polyvinyl chloride microparticles both separately and in a mixture, since soil particles P1 and P2 do not acquire similar properties. When fluorescein and eosin were used, polyvinyl chloride microparticles and soil practically did not fluoresce. It has been established that coloring does not affect the polyvinyl chloride chemical structure. Dyes are not washed out of polyvinyl chloride microparticles after repeated washing with water. The laboratory experiment showed that it is possible to detect and quantitation polyvinyl chloride microparticles in soil at the 0.1 % concentration by weight with a relative error of about 30 %. It is possible to use fluorescently labeled polyvinyl chloride microparticles with rhodamine B and rhodamine G when conducting phytotests. This research demonstrates for the first time the possibility of selective staining of polyvinyl chloride microparticles with rhodamine B and rhodamine G in a mixture with soil due to the observed fluorescence and their detection in a concentration of 0.1 % by weight. The results obtained expand knowledge in the field of monitoring microplastics in soil and, since today there are no standardized methods for detecting this pollutant, it can be used in their development. Fluorescently labeled polyvinyl chloride microparticles with rhodamine B and rhodamine G are planned to be used in phytotests as part of experiments on the hygienic justification of the maximum permissible concentration of the pollutant in the soil.
It is known that when optical radiation passes through the phase modulator of a multifunctional integrated-optical chip (MIOC), along with the modulation of the phase of the light wave, there is a change in the power of optical radiation at the output of the coupled waveguide. This modulation is parasitic, and its magnitude depends on the control voltage at the modulator electrodes. Amplitude modulation leads to an error in the output signal of highly sensitive phase sensors, in particular, in a fiber optic gyroscope. This paper presents an experimental study of the change in the spatial intensity distribution (mode field) at the end of channel waveguides of a multifunctional integrated-optical chip under the action of an applied voltage. The experimental setup was assembled with a radiation source in the form of a singlefrequency laser RIO ORION with a central emission wavelength of 1550 nm. The optical receiver was an infrared camera SP503U-1550 with radiation registration in the wavelength range 1440–1605 nm, pixel size 9.9 × 9.9 μm and matrix size 640 × 480 pixels. The multifunctional integrated-optical chip was fabricated by titanium diffusion technology in Ti:LiNbO3 X-cut lithium niobate crystal substrate. A constant control voltage in the range from –10 V to +10 V was applied to the electrodes of the MIOC phase modulator. The distribution of optical radiation intensity in MIOC waveguides and in a single-mode optical fiber with an elliptical ESC-4 straining sheath was analyzed by calculating the overlap integral. The effect of electric field on optical radiation in MIOC waveguides is experimentally demonstrated. It is demonstrated that at constant voltage at the control electrodes of the phase modulator change in the radiation intensity distribution at the output of channel waveguides is observed. The observed changes correlate with parasitic amplitude modulation. The occurrence of parasitic amplitude modulation is due to the propagation of parasitic optical radiation along the waveguide. This phenomenon is caused by the escape of lithium oxide from the surface layer of lithium niobate into the gas phase during the technological process of titanium diffusion. The studies have allowed us to better understand the mechanisms of parasitic amplitude modulation in the phase modulator of MIOC and to develop practical recommendations for their elimination. These results can be useful for specialists working on research in the field of highly sensitive phase sensors using integrated optic circuits. 
Assessment of the quantitative composition of hydrate formation inhibitors by their infrared spectra
Kozhevina Iuliia S. , Nosenko Tatiana N. , Uspenskaya Mayya Valerievna
An approach is proposed to determine the concentrations of active components in a thermodynamic type inhibitor based on its infrared spectrum. The relevance of the proposed method is due to its expressiveness and high degree of selectivity in comparison with traditional approaches for determining the quantitative composition of solutions of organic compounds. It is proposed to use the method of infrared spectrometry with Fourier transform. The method allows you to determine the concentrations of substances in solutions. However, the determination of concentrations of substances in mixtures containing more than three components is complicated, especially in solutions of organic compounds due to the presence of overlapping oscillation regions of characteristic groups. To solve the problem of determining the concentration of substances in multicomponent solutions, the regression method of projection onto latent structures was used, which belongs to chemometric analysis methods and has become widespread as a method of quantitative forecasting. The sample for the construction of calibration dependencies within the framework of the method used included the spectra of solutions obtained in the mode of disturbed total internal reflection. Models have been constructed to determine the concentrations of substances in a four-component aqueous alcohol solution. Substances to be determined: water, methanol, ethanol, ethylene glycol. The effectiveness of the constructed mo dels with a training sample, including spectra of samples with minimal preprocessing — correction of the baseline, has been confirmed. The optimal set of training samples has been determined to obtain a result with the minimum possible error, provided that the component content of the samples in the training sample does not exceed n – 1, where n is the determined amount of substances. Training the model on a sample consisting of spectra of two- and three-component solutions provides prediction of the concentration of substances with an error of up to 10 %. The proposed method will allow rapid analysis of the composition of thermodynamic inhibitors of hydrate formation. The results of the work can be used in oilfield chemistry to assess the inhibitory ability of hydrate formation inhibitors used to prevent the formation of gas hydrates during the extraction, preparation or transportation of hydrocarbons.
Magneto optical properties of atmospheric air molecules
Dhobi Saddam Husain, Nakarmi Jeevan Joyti, Yadav Kishori, Gupta Suresh Prasad
The magneto-optical properties of atmospheric air molecules describe how air molecules interact with both magnetic fields and light. Studying these properties is crucial for understanding atmospheric dynamics, enhancing remote sensing for environmental monitoring, developing new materials for sensors and optical devices, refining medical imaging techniques like Magnetic Resonance Imaging, and advancing fundamental scientific knowledge with potential practical applications. The objective of this study is to investigate the magnetic optical properties of air within a weak magnetic field ranging from 0.122 T to 0.986 T using experimental methods. The analysis focuses on the variations in transmittance across the visible spectrum with changes in magnetic field intensity. Results indicate a decrease in transmittance with increasing wavelength, demonstrating a direct correlation between transmittance and magnetic field strength. The magneto-optical properties, specifically transmittance, exhibit a decreasing trend with increasing wavelength, with minimum and maximum transmittance values recorded at 460 nm and 664.755 nm, respectively. Additionally, the transmittance of air spectrum is directly influenced by the applied magnetic field. Moreover, the intensity ratio associated with Raman spectra shift decreases with increasing Raman spectra shift, with higher intensity ratios observed in the presence of a magnetic field compared to non-magnetic conditions. Furthermore, the magnetooptical response tends to shift towards higher wavelengths with increasing magnetic field strength.
Femtosecond laser modification of the ZnO:Ag sol-gel films within dichroism emergence
Gresko Vladislav R., Sergeev Maxim M. , Smirnova Victoria V., Dolgopolov Arthur D. , Sokura Liliia A. , Galina K. Kostyuk, Grigoryev Evgeniy A.
Polarization of femtosecond laser radiation influence on the windings of ellipsoidal silver nanoparticles and their orientation in zinc oxide sol-gel films was studied, which caused the appearance of dichroism in the films of the irradiation field. Unlike silver-containing glasses, where this mechanism was discovered, it has hardly been studied in thin sol-gel films before. Femtosecond laser pulses with a high degree of repetition and linear polarization controlled the shape, size and orientation of silver nanoparticles which was oriented horizontally along and across the direction. For dichroism to occur, it is necessary to ensure high-quality separation of laser transducers by Ag nanoparticles and the absence of differences in the zinc oxide matrix. Dichroism in such ZnO:Ag films was investigated by optical microscopy and spectrophotometry away from light. Analysis of the size, content, shape and location of nanoparticles in the film was conducted taking into account electron microscopy. It has been shown that the relationship between dichroism as a result of exposure of the film to laser radiation with energy density ranging from 43 to 99 mJ/cm2 per pulse and flow velocity of 1 mm/s. It was investigated that at given fluence, the interruption of ellipsoidal nanoparticles, most of which are simply oriented along the polarization line of the femtosecond transformation, occurs depending on the direction of the transformation. As a result of laser treatment, modified areas of the film acquired dichroism. When the polarization axis of the incident light was parallel to the direction of linear polarization of the femtosecond radiation with which the regions were recorded, the plasmon resonance peak shifted to the long-wavelength deflection region. When the changed zones were rotated by 90°, the peak of the plasmon resonance shifted to a shorter wavelength region relative to. At fluence above 99 mJ/cm2, dichroism remained, but it decreased sharply, the size of nanoparticles decreased and began to gradually destroy the film matrix with the formation of nanoscale pores and cracks. Obtained results can be used to register polarization-sensitive elements of small sizes, the spectral transmission of which will depend on the orientation of the linear polarization vector of the light incident on them. The proposed method allows adjustment of plasmon resonance peak position in the spectral range from 450 to 650 nm, which can also be used to increase the sensitivity of photodetectors in the specified spectral range.


The study of plasma generation in liquids is relevant for many applications, especially for increasing the efficiency of terahertz radiation generation. This work investigates the relationship between the laser excitation wavelength and the plasma electron density in liquid water in the near-infrared spectral range. Using numerical simulation methods based on the Keldysh theory, patterns of changes in the ionization rate and changes in the plasma electron density depending on the excitation wavelength are analyzed. The results show the mutual influence of above-threshold ionization and tunneling effects when the Keldysh parameter is close to one. A decrease in plasma electron density with increasing excitation wavelength has been shown. However, in certain wavelength ranges a local increase in plasma electron density was observed. The theoretical results obtained are consistent with the experimental data of other scientific groups. This theoretical study provides valuable information on the modulation of plasma electron density by changing laser excitation wavelengths, which is important for increasing the efficiency of terahertz radiation generation.
Luminescent and colorimetric properties of silica-coated spherical cadmium telluride nanocrystals in an external electric field
Daibagya Daniil S. , Ambrozevich Sergey A., Zakharchuk Ivan A. , Osadchenko Anna V., Selyukov Alexandr S.
The study concerns the behavior of optical and colorimetric properties of cadmium telluride semiconductor colloidal quantum dots covered with silica shell (CdTe/SiO2, core/shell) in an external constant electric field has been studied. To date, the electric field is known to lead mainly to quenching and red shift of the luminescence spectra of quantum dots; however, in most of the corresponding studies only the behavior of band-edge luminescence is considered. In this work, in addition to the luminescence due to interband transitions, the effect of the electric field on the trap-related luminescences of core/shell quantum dots is studied. Semiconductor nanocrystals were synthesized by colloidal chemistry methods. The product mixture was a solution of quantum dots in an aqueous medium. To investigate the optical properties of CdTe/SiO2 nanoparticles in an external electric field, a series of samples was fabricated on the basis of an optically passive cellulose film, in the pores of which quantum dots were embedded. The final sample was a cellulose film with quantum dots sandwiched between two glasses with transparent indium tin oxide electrodes. The strength of the constant electric field applied to such structures reached 140 kV/cm. Photoluminescence spectra of the investigated nanostructures were recorded using a CCD spectrometer. As a result of the experiments it was found that the presence and subsequent increase of the external electric field leads to quenching of the intensity of both band-edge and traprelated photoluminescence of quantum dots. This fact is associated with a decrease in the overlap between electron and hole wave functions under the action of the electric field. It is also shown that at moderate field strength there is a slight increase in the total photoluminescence intensity. This observation can be related to impeded charge carrier trapping. The demonstrated quenching of luminescence intensity is also consistent with the results of other authors who have shown a decrease in the absorption of quantum dots in external electric fields. The stability of colorimetric characteristics of the spherical nanoparticles in an external electric field has been demonstrated. The results of the study can be used for development of optoelectronic devices based on CdTe/SiO2 nanoparticles. 


More recently, permanent magnet synchronous motors (PMSM) have been widely applied to power source for different applications, such as high precision tracking systems, standalone electric and unmanned aerial vehicles, industrial robotics, marine propulsions, etc., due to their advantages to conventional competitors for example induction motor with squirrel-cage rotor. In order to reduce the cost of AC drive, the removal of the mechanical sensors is required. Hence, the sensorless motor control is more preferable and is based on electrical measurements, namely, three-phase currents and voltages. The paper is devoted to sensorless field-oriented control design procedure for a non-salient PMSM. The proposed control strategy is employed on full order sliding-mode observer which provides the output insensitivity to parameter changes and disturbances. In order to reduce th e high-frequency chattering and enhance the rotor position estimation quality and accuracy, the band-pass filter with tracking of the central frequency to the speed reference is applied. To obtain actual information about the unmeasurable rotor position and speed, the phase-locked loop with cascade connection of adaptive proportional-integral controller is employed. A simulation of the dynamic starting mode of a PMSM under zero initial conditions has been performed by MATLAB/Simulink environment. As can be concluded from the simulation results, proposed sensorless field-oriented control strategy provides quick response as well as low rotor position estimation error both transient and steady-state behavior. The research significance of proposed PMSM sensorless field-oriented control strategy is to provide the wide range of motor speed operation, strong robustness of estimated rotor position to parameter perturbations as well as quality suppression of high frequency chattering effect owing to the switching attribute and the internal control discontinuity of sliding mode, whereby the practical application of a sensorless variable-frequency synchronous electric drive is expanding.


The effective functioning of modern production systems is impossible without using of methods for processing and analyzing data continuously generated during operation. Limitations imposed on the speed and precision of determining the required indicators lead to the need of optimizing the algorithms used. Multisensor systems, as a rule, have an excessive number of cross-sensitive sensors, and their signals can be used to determine various indicators of a similar physical nature. The purpose of the study is to improve the algorithm for processing multidimensional data from multisensor systems. Principal component analysis was applied as part of the developed algorithm for the formation of informative features. Partial least squares regression was used to build regression models. The data set for approbation of proposed approach was obtained through potentiometric measurements using a digital mV-meter. An experiment is described using a multisensor system called “electronic tongue”, consisting of 12 cross-sensitive potentiometric sensors. In the experiment, real samples of vegetable oils acted as analyzed objects. Regression models were built to determine three quality indicators of vegetable oils: peroxide value, para-anisidine value and total tocopherol concentrations. The results of the study were compared with known scientific works. A comparative analysis allowed us to conclude that using of the most informative sources selected according to the proposed algorithm can significantly reduce the root mean square error of prediction. The results obtained can be used both in systems for identifying deviations in production processes in “Industry 4.0” enterprises, and for expressly identifying counterfeit products.
Lithium tetraborate co-doping with transition and alkali metals
Zakharchuk Ivan A. , Daibagya Daniil S. , Osadchenko Anna V., Danilkin Mihail I., Ambrozevich Sergey A., Selyukov Alexandr S.
Luminescent properties of tissue-equivalent detectors have been studied. The detectors are made of lithium tetraborate and doped with magnesium, manganese, or tin. Analysis of the results obtained makes it possible to confirm the complexity of luminescence centers in lithium tetraborate without using structural analysis methods. For the first time, the effect of the method and order of introducing impurities on the storage properties of the studied materials was demonstrated and explained. The synthesis of the lithium tetraborate host occurred through the reaction of H3BO3 and Li2CO3. The binding agent was SiO2. Magnesium, manganese, or tin dopants were introduced during the synthesis of the host or later. The final stage of the synthesis was pressing of the powder into tablets and sintering in argon at 1158 K. The photoluminescence and pulsed cathodoluminescence signals were recorded by CCD-spectrometers. Portable pulsed electron accelerator was used for excitation of cathodoluminescence. Thermally stimulated luminescence was recorded by a special dosimetric reader with a heater and photo muliplier tube after exposure of the samples to an electron beam. Photoluminescence spectra, cathodoluminescence spectra, and glow curves were obtained for five samples of lithium tetraborate with various impurities, namely, magnesium, manganese, and tin. A comparison of the results was made to identify how the intensity signals depend on the amount of impurities and order of their introduction. It was found that the synthesis procedure and the order of introducing the dopants affect the luminescent properties of the materials. It has been suggested that the impurities take different positions in the lithium tetraborate structure. Predominant introduction of a particular impurity at a particular site leads to the following result. Doping with tin provides an increase in the number of luminescence centers of manganese and significantly sensitizes its luminescence, while doping with magnesium leads to the opposite result. The results indicate that it is possible to create advanced tissue-equivalent detectors with tailored luminescent. Depending on the dose of ionizing radiation, the use of material with different sensitivity and radiation resistance is required. Thus, the production of detectors based on lithium tetraborate and the described impurities in the future will give an opportunity to create a promising group of ionizing radiation detectors with various properties. 
Analysis of chemical interactions during filling a cesium vapor cell for a quantum magnetometer
Yulmetova Olga S., Shcherbak Alexander G. , Reshetnyak Polina E., Zavitaev Alexander S., Alexander N. Shevchenko, Yulmetova Raliya F.
The results of the development and research of the technological process for manufacturing spherical vapor cells are presented. Such cells are used in quantum devices, such as magnetometers, gyroscopes, and atomic clocks. Their work is based on optical pumping and detection of the state of alkali metal vapors, in particular cesium. To increase the lifetime of cesium spin polarization in the vapor cell, it is filled with a buffer inert gas. The quality of cell manufacturing directly affects such device characteristics as the width of resonance lines and the achievable signal-to-noise ratio. The proposed cell manufacturing technology simplifies the technological process, eliminates the use of specialized equipment, and increases the reproducibility of results associated with chemical reactions of an alkali metal with foreign impurities in a buffer gas. This is achieved by detecting the formed compounds and excluding them from the composition of the gaseous environment of the cells through the selection of a reasonable sequence of technological operations in the cell manufacturing cycle. The use of traditional methods of X-ray diffraction is associated with the need to depressurize the vapor cell with cesium which leads to the inevitable reaction of cesium with components of the air environment. The work proposes a two-stage analytical assessment of the composition of the gas mixture. At the first stage, the thermodynamic resolution of all possible reactions in the cesium-nitrogen-impurity oxygen system is determined. At the second stage, the color spectrum of the spectra of experimentally obtained reaction products is compared with the color of the products of thermodynamically allowed interactions. Thermodynamic analysis based on a two-stage approach made it possible to identify the formation of cesium suboxides in a vapor cell when it was heated in the temperature range of 273–700 K. To exclude them from the composition of the vapor cell, a sequence of operations was proposed. It involves the formation of an ampoule using the glass blowing method which has a technological cylindrical part and a spherical cell connected to it by a constriction. High purity cesium encapsulated in a glass shell is placed into the technological part of the ampoule, after which the ampoule is evacuated. After opening the capsule with cesium, thermal distillation of pure cesium into a spherical zone takes place. The technological process is completed by filling the cell with buffer gas, after which it is sealed off. The absence of heating during filling a vapor cell with nitrogen significantly simplifies the technological process and minimizes the amount of foreign impurities in the form of cesium suboxides in the gas mixture.
Polymer-salt synthesis and study on structure of vanadium-doped yttrium-aluminum garnet
Sergei K. Evstropiev, Ostrovskii Vyacheslav A., Makarov Konstantin N. , Bulyga Dmitry V. , Valery M. Volynkin, Sandulenko Alexander V., Dukelskii Konstantin V., Polishchuk Grigoriy S.
Nanoscaled YAG:V powders were synthesized using low-temperature polymer-salt method. A comparison of their structure with monocrystals structure was performed. Structure, morphology and chemical composition of materials were studied using XRD, SEM and energy-dispersive X-ray spectroscopy. Estimation of average sizes of nanocrystals and crystal cell parameters was performed based on XRD data. The results were compared with the results obtained earlier for YAG:V monocrystals. Nanopowders synthesized at 1000 °C consist from microscopic aggregates of YAG:V nanocrystals with average size of 43 nm and crystal structure characteristic for YAG monocrystals. It was found that V3+ incorporation and their substitution of aluminum ions leads to distortion of crystal cell. It was shown that this phenomenon is observed both in YAG:V monocrystals and nanopowders synthesized using low-temperature polymer-salt method. The infrared spectroscopy data shows the similarity of the monocrystal and nanopowders structure. Obtained powders can be applied for fabrication of light-absorbing optical ceramics and organo-inorganic composites.


The primary idea of this paper is the implementation of the Optimal Key-Tuned Rivest Shamir Adelman technique, a dual authentication approach for effective data sharing in the cloud within hospital data management. The system begins with user registration with the Trusted Center where user details are provided. An authentication scheme utilizing the Caesar cipher and the Secure Hashing Algorithm 512 ensures integrity. The encryption process employs the Optimal Key-Tuned Rivest Shamir Adelman scheme for secure file transmission. To enhance key creation procedures in the Rivest Shamir Adelman model, the Improved Butterfly Optimization Algorithm technique is utilized to maximize throughput. Finally, dual authentication is conducted on the receiver side for file access and downloads from the cloud server. This additional layer of authentication fortifies the system resilience against unauthorized access, ensuring that only legitimate users can interact with the healthcare data stored in the cloud. The results indicate that the system outperforms other state-of-the-art systems enabling secure sharing and downloading of health data in cloud environments.
Methods and algorithms for restoring smeared and noisy images by numerically solving integral equations (IE) are considered. The algorithms are illustrated by the restoration of distorted images of celestial bodies using the example of images of Saturn, Jupiter and their satellites against the background of the starry sky. Images of objects may be weak, which will require increased exposure and may lead to a mismatch between the rotations of the Earth and a telescope, and then a smear image of the object will occur. The article proposes to eliminate smear by mathematical and computer processing of the distorted image. In this case, the type and the parameters of a smear may be practically unknown or known inaccurately. The novelty of the proposed solution lies in the fact that the type and the parameters of a distortion, and therefore the kernel of an IE or the point spread function (PSF), are determined by the original “spectral method”. In the direct problem, modeling the smear and noise in receivers (telescopes) is performed by calculating convolutiontype integrals. In the inverse problem, image smearing is performed by IE solving with the Wiener parametric filtering method using the new “spectral method” for determining the kernel of the IE as well as filtering the noise by the Tukey median filter and the new modified filter. Error estimates for each operation are obtained. A technique has been proposed that makes it possible to eliminate, through the use of mathematical and software tools, images of planets, natural and instrumental noise, image smear, and also to obtain the clear images of Saturn, Jupiter and their satellites. Undistorted images of Saturn and Jupiter with their satellites were taken from astronomical catalogs. By modeling, we have obtained a distorted (smeared and noisy) image of Saturn with given distortion parameters (smear angle θ and smear value Δ) and a truly distorted image of Jupiter with unknown distortion parameters determined by the spectral method. Next, the image of Saturn with its satellites was restored by solving the IE. Image processing of Jupiter was also carried out, in which, to eliminate image smear by solving the integral equation, the “spectral method” was used to determine the smear parameters, and therefore the PSF and the kernel of the integral equation. The performance of the proposed method is determined both by visual assessment of the reconstructed image and by calculating the reconstruction error. The proposed technique makes it possible to eliminate in images of various space objects, in particular, Saturn and Jupiter, the natural or instrumental noise, as well as image smear, and to highlight faint objects (satellites, etc.) against the background of stars.
The constantly emerging need to increase the efficiency of solving classification problems and predicting the behavior of objects under observation necessitates improving data processing methods. This article proposes a method for improving the quality indicators of machine learning models in regression and forecasting problems. The proposed processing of information sequences involves the use of input data segmentation. As a result of data division, segments with different properties of observation objects are formed. The novelty of the method lies in dividing the sequence into segments using the quality functional of processing models on data subsamples. This allows you to apply the best quality models on various data segments. The segments obtained in this way are separate subsamples to which the best quality models and machine learning algorithms are assigned. To assess the quality of the proposed solution, an experiment was performed using model data and multiple regression. The obtained values of the quality indicator RMSE for various algorithms on an experimental sample and with a different number of segments demonstrated an increase in the quality indicators of individual algorithms with an increase in the number of segments. The proposed method can improve RMSE performance by an average of 7 % by segmenting and assigning models that have the best performance in individual segments. The results obtained can be additionally used in the development of models and data processing methods. The proposed solution is aimed at further improving and expanding ensemble methods. The formation of multi-level model structures that process, analyze incoming information flows and assign the most suitable model for solving the current problem makes it possible to reduce the complexity and resource intensity of classical ensemble methods. The impact of the overfitting problem is reduced, the dependence of processing results on the basic models is reduced, the efficiency of setting up basic algorithms in the event of transformation of data properties is increased, and the interpretability of the results is improved.
A method has been proposed to eliminate slight motion blur in the image. The method is implemented in three stages. Blur estimation is achieved by prior information on the distribution image gradient. The Gaussian Orientation Filter (GOF) fits the prior information to find the regression coefficients. Order combines different estimate GOF parameters to generate a removal blur filter. Estimation parameters are fixed and set blur on the image to produce an image without boosting the noise and unwanted. The proposed model optimization solves the problem by minimizing the loss function. The suggested method applies to outdoor and indoor video acquired by modern smartphones. The experiment result display is accurate for the full regression motion blur model. The suggested model example on video dataset conditions has 23 s video time long and 228 MP dataset size. Measurement evaluation established on time consumer, Structural Similarity Index Measure and Peak Signal-to-Noise Ratio. Experimental results show that the image artifact phase is less consuming computational time. The proposed model has a minimized cost function and generates image quality. 
Artificial intelligence has become widespread in image processing tasks. At the same time, the number of vulnerabilities is increasing in systems implementing these artificial intelligence technologies (the attack surface is increasing). The main threats to information security can be implemented by introducing malicious perturbations into the input data, regardless of their type. To detect such attacks, approaches and methods have been developed based, in particular, on the use of an auto-encoder or the analysis of layers of the target neural network. The disadvantage of existing methods, which significantly reduce the scope of their application, is binding to the dataset or model architecture. This paper discusses the issues of expanding the scope (increasing scalability) of methods for detecting L0-optimized perturbations introduced by unconventional pixel attacks. An approach to detecting these attacks using statistical analysis of input data, regardless of the model and dataset, is proposed. It is assumed that the pixels of the perturbation embedded in the image, as a result of the L0-optimized attack, will be considered both local and global outliers. Outlier detection is performed using statistical metrics such as deviation from nearest neighbors and Mahalanobis distance. The evaluation of each pixel (anomaly score) is performed as a product of the specified metrics. A threshold clipping algorithm is used to detect an attack. When a pixel is detected for which the received score exceeds a certain threshold, the image is recognized as distorted. The approach was tested on the CIFAR-10 and MNIST datasets. The developed method has demonstrated high accuracy in detecting attacks. On the CIFAR-10 dataset, the accuracy of detecting onepixel attack (accuracy) was 94.3 %, and when detecting a Jacobian based Saliency Map Attack (JSMA) — 98.3 %. The proposed approach is also applicable in the detection of modified pixels. The proposed approach is applicable for detecting one-pixel attacks and JSMA, but can potentially be used for any L0-optimized distortions. The approach is applicable for color and grayscale images regardless of the dataset. The proposed approach is potentially universal for the architecture of a neural network, since it uses only input data to detect attacks. The approach can be used to detect images modified by unconventional adversarial attacks in the training sample before the model is formed. 


The results of a study of small transverse vibrations of a string and Bernoulli-Euler beam with a concentrated inclusion are presented. The physical properties of the string and the beam are assumed to be constant, the inclusion is modeled using the Dirac delta function and described by two parameters: location and mass. The problem of determining these parameters by measuring the shift of the resonant frequency is considered. The basic method is the eigenfunction expansion of displacement. Expansion coefficients are determined using the Greenberg method. Their substitution into the original expansion in the case of a point defect allows us to obtain a characteristic equation that determines the effect of inclusion on the string and beam natural frequencies. An analytical solution to the problem of small transverse vibrations of a string and Bernoulli-Euler beam with a point inclusion is presented. A method for possesing frequency equations that completely determine the influence of inclusion on the oscillation spectrum is proposed. Basing on the proposed method, expressions for identifying the inclusion parameters are derived, and the dependences of these parameters on the resonant frequency shift are presented. The possibility of independently determining the mass and location of the defect by measuring the shift of two natural frequencies is shown. The work is aimed at developing analytical methods for modeling the dynamics of continuum mechanical systems with a heterogeneous structure. The description of their dynamic response is of significant practical interest for creating various types of sensors, such as accelerometers, speed sensors, pressure sensors and others. The results obtained in this article can be used in the elaboration of mass detectors, the operation of which is based on changes in the natural frequency of oscillations.
Restoration of unsteady heat flow from a thermal energy accumulator by solving the inverse heat conduction problem
Pilipenko Nikolay V., Kolodiychuk Pavel A. , Zakharova Victoria Yu. , Faizullin Rafael O.
This paper considers the problem restoring a non-stationary heat flow from a coolant to a heat-storing substance of a separate element of a thermal accumulator. Solving the problem allows avoiding errors associated with averaging the heat flow over all battery cells, and provides the opportunity to find the optimal sizes and composition of the filler for each battery cell. The problem is especially relevant for cascade batteries where cells with different fillers are simultaneously used. A comparison is made of two methods for solving the problem. The first method is based on numerical simulation of the thermal energy storage discharge process using the Computational Fluid Dynamics software package. The second approach proposed by the authors is based on the parametric identification of a differential-difference model of heat transfer with the solution of the inverse problem of heat conduction together with coefficient smoothing calculation. The proposed method makes it possible to smooth out abruptly changing thermophysical characteristics and take into account the moving phase boundary of a substance. The method for solving the inverse heat conduction problem can significantly reduce the recovery time of non-stationary boundary conditions of heat transfer for the entire battery and, thus, reduce the requirements for computing resources when designing and optimizing the battery by facilitating experimental search. For the first time, the use of the method of parametric identification and calculation of smoothing coefficients for solving the Stefan problem was considered and proposed. The results obtained can be used to calculate the heat flow from an individual element of a thermal energy accumulator.
Management of space surveillance radar temporal resource on fuzzy set theory
Babkin Yuri V., Zverev Gleb P. , Timoshenko Alexander V. , Perlov Anatoly Yu., Bulatov Marat F.
This paper addresses the problem of optimizing the use of temporal resources of a radar station (RS) under limited time resources. Special attention is given to the necessity of considering a multitude of compensatory optimality criteria when allocating the RS operating time. The proposed approach is based on the use of fuzzy set theory which represents an innovative solution in the context of this task. The task of managing the RS temporal resources is formulated as the search for an optimal work schedule among all potentially possible options. This schedule should minimize the values of all partial optimality criteria. Fuzzy set theory is applied to solve this problem, allowing for the consideration of uncertainty and variability in task execution conditions. An algorithm for managing the RS temporal resources was presented. The review results confirm the probable increase in efficiency, especially in conditions of acute shortage of temporal resources, ensuring their optimal distribution among current tasks. Furthermore, the algorithm enables decisions to be made about the possibility of performing special or additional tasks without compromising the main monitoring functions. The review of the proposed algorithm provides a basis for hypothesizing its advantages over traditional methods of managing the RS temporal resources. In particular, the use of fuzzy set theory allows for more flexible responses to changes in task execution conditions and enhances the overall adaptability of the system. In the future, this approach could be adapted and applied in other areas where there is a need for resource optimization under conditions of limitation and uncertainty of external factors.
Quantification and modeling of ankle biomechanical characteristics
Musalimov Viktor M., Perepelkina Svetlana Yu. , Elena N. Gapeeva, Paasuke Mati A., Ereline Jaan J., Erofeev Mikhail A.
Calculation method for ankle joint biomechanical characteristics is developed: gear relation, ankle joint rigidity, foot inertia moment. The basis of research is the experimental data on flexion-extension-rotation movement of ankle joint and foot walking reaction obtained in the laboratory of kinesiology and biomechanics of the Tartu University, Estonia. Conservation principles of angular momentum were used for foot inertia moments calculation. Angular momentum was calculated according to foot reaction and further estimation of reactive force impulse data. The free transfer dynamics method (FTD-method) was suggested that allowed assessing ankle joint rigidity. Ankle joint gear relation has been calculated for the first time. Foot inertia moments in reference to two ankle joint axes have been calculated on the basis of foot reaction experimental data and angular movement markers data. Experimental data in the phases of foot transfer with further foot movement modeling in this phases have been used in order to assess ankle joint rigidity. Practical relevance of this research is defined by the perspective of further researches and experiments, for example, with the usage of inertial sensors for personalized walk data assessment for patients with remote condition monitoring and information transfer to rehabilitation centers. The given assessments of angle joint rigidity are useful for biomechatronic systems engineering.
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