The article is devoted to increasing the volumetric accuracy of multi-axis machine tools. Based on the model of measurement and calculation of the volumetric geometric error of machine tools presented by the authors, a method has been developed which allows to signifi cantly improve the accuracy of the movement of the operating unit of a three-axis metal-cutting machine tool to a given point. The astatic law and the calculation of the coordinate correction according to the differential geometric model of the volumetric error are used to control the movement of the operating unit. The developed method is implemented programmatically and allows to perform the correction in the control program represented in G-code. As a result of experiments on software correction of volumetric errors according to the developed method, conducted at the State Engineering Centre of the Moscow State University of Technology “STANKIN” on a threeaxis CNC machine tool, a signifi cant reduction (up to 90 %) of geometric volumetric errors was shown. The developed method can be used to improve the accuracy of metal-cutting machine tools by creating postprocessors that calculate corrections to the coordinates set in the control system based on the results of interferometric measurements.

Keywords: volumetric accuracy, interference measurements, three-axis machine tools, machine tool accuracy, geometric errors, astatic control law, mathematical modelling, differential geometry

The paper is dedicated to the current issue of microwave photonics: the development of optoelectronic oscillators for ultra-high frequency signals. The interest in creating such oscillators is largely driven by the possibility of obtaining signals with low levels of phase noise. The use of multiplexers as fi lters in optoelectronic oscillators opens up new possibilities in building optoelectronic systems for generating ultra-high frequency signals at different frequencies. This implementation of the optoelectronic generator allows for discrete regulation of the frequency of the generated signal, or generating the signal simultaneously at multiple specifi ed frequencies. In the investigated system, phase noises were measured: less than 100 dBc/Hz at 1 kHz offset from the carrier frequency and less than 130 dBc/Hz at 10 kHz offset from the carrier frequency. The obtained results confirm the potential use of multiplexers as bandpass filters, which is important for the development and optimization of optoelectronic oscillators

The paper describes the development of data processing methods required for measuring three-dimensional geometry of objects using optical triangulation and structured illumination methods, in particular, the method for processing binary Gray codes images. An image processing algorithm is proposed that allows decoding the binary code generated by an optical radiation source. The code is contained in the dependence of the intensity distribution of the surface image of the object observed by the photodetector on the frame number. The proposed algorithm ensures stable binarization of Gray code images under conditions of a limited dynamic range of the photodetector and arbitrary light-scattering properties of the surface of the measured object without using inverted projected images. The proposed algorithm can be successfully applied in systems for measuring three-dimensional geometry of complex-profi le objects, the operation of which is based on the triangulation principle (the operation of the measurement systems, not the objects, is described) and the structured illumination method. It is shown that for all possible ratios of the recorded radiation intensity and the dynamic range of the photodetector, the method correctly decodes the values of the Gray code encoded in structured illumination. In this case, the deviation of the Gray code decoding results is caused only by the noise of the received images and does not distort the measurement results. The main advantage of the proposed algorithm is the ability to use almost twice as few structured highlights to decrypt the Gray code compared to the algorithm using inverted code images.

This article addresses an urgent challenge in the development of effi cient micromechanical tools for the manipulation of microobjects related to microelectromechanical systems. Recently, layered amorphous-crystalline ribbons of rapidly quenched TiNiCu alloy exhibiting a two-way shape memory effect have been successfully used to create microtweezers. The study outlines a method and presents an original experimental setup designed to determine the parameters associated with the two-way shape memory effect in such ribbons. The thermomechanical properties of an amorphous-crystalline composite, characterized by an amorphous layer thickness of 25 μm and a crystalline layer thickness of 7 μm, produced by melt spinning technique, were investigated. The effect of multiple thermal cycles in the shape memory effect temperature range was studied. The maximum reversible bending strain observed in the ribbon exceeds 0.2 %, which facilitates the development of micromechanical devices such as microtweezers. An increase in the number of thermal cycles from 1 to 100 resulted in a signifi cant enhancement of the reversible strain (by approximately 1.2 times) and a nearly twofold reduction in the temperature hysteresis associated with the two-way shape memory effect. The characteristic temperatures exhibited minimal variation, with the exception of the onset temperature of shape change during cooling, which showed a marked increase. The results obtained make it possible to improve the functional characteristics of micromechanical devices, based on amorphous-crystalline TiNiCu alloy ribbons by increasing their reliability and operational speed, as well as reducing their dimensions.

The process of thermal engineering surveys of buildings is considered. This process includes in-kind measurements of heat flux density and temperature on the surfaces of building envelope. Based on the obtained measurement results, the reduced heat-transfer resistance is calculated and compared with the required design values for building. It is shown that when calculating the heat-transfer resistance of the building envelope based on the survey results, methodological errors may occur, which are caused by external natural thermal effects on the building and internal non-stationary heat fl ows in the building envelopes. During in-kind thermal engineering surveys of enclosures of buildings of any type, these methodological errors are a priori unknown, since the measurement conditions differ from the conditions of thermal engineering tests in special climatic chambers, where a stationary difference in air temperature is maintained on the internal and external surfaces of the building envelope. To assess the methodological errors in thermal engineering surveys of buildings in natural conditions that begin on any day of the calendar year and last for several days, physical and mathematical modeling of unsteady heat transfer in the building envelope is performed. The following thermal effects, close to real ones, are taken into account during the modeling: outside air temperature; direct and diffuse solar radiation; radiant heat exchange with the environment. Enclosing structures with low and high thermal protection and thermal inertia are analyzed. Possible values methodological errors of heat engineering surveys are calculated using archived meteorological data for the Moscow region. It is shown that, depending on the season and weather conditions, their values can vary from several units to several tens of percent. The conditions for conducting surveys are determined taking into account different levels of methodological errors. A comparison of two standard methods for calculating heat transfer resistance is carried out and it is shown that the methods give different levels of methodological errors. The results obtained will be useful for specialists conducting heat engineering surveys of buildings and structures using non-destructive testing methods.

In order to improve the accuracy of cancer diagnosis, a new convolutional neural network architecture is presented, which provides automatic segmentation and detection of kidney tumors on three-dimensional images obtained by computed tomography. The proposed approach is based on the integration of three complementary technologies: multilevel convolutional processing, residual connections and U-Net architectural principles. This approach ensures efficient processing of voluminous medical data. An original neural network system for segmentation of kidney images obtained by computed tomography and detection of kidney tumors has been built. To validate the system, a comprehensive experiment was conducted using the publicly available KiTS19 dataset (Kidney Tumor Segmentation 2019) provided by the University of Minnesota Clinic through the Grand Challenge platform. The dataset includes 300 labeled images of kidneys obtained by computed tomography, with confirmed diagnoses. The experiment consisted of the following stages: dataset preprocessing, including normalization and augmentation; system training for 210 cases; validation on an independent sample of 90 cases. The results of the experiment demonstrate the high diagnostic efficiency of the system: the accuracy of automatic segmentation of anatomical structures of the kidneys was 96 % (according to the Dice coefficient); the accuracy of detection and segmentation of tumor formations has reached 91 % (according to the Dice coefficient). The results obtained can be applied in the following areas of clinical practice: preoperative planning and navigation during organ – preserving operations; automated screening of studies using computed tomography for early detection of kidney tumors; quantitative assessment of the dynamics of tumor growth in monitoring the course of the disease; support for clinical decision-making in oncourology.

The necessity of timely diagnostics and forecasting of the fl ight crew performance level under the infl uence of a complex of unfavorable factors that reduce the effi ciency of professional activity and disrupt the functional state of pilots is considered. It is shown that the most frequent functional state of “fatigue” occurs in pilots during aircraft control. A method for assessing the functional state of civil aviation pilots has been developed, which is based on determining the value of the integral indicator with subsequent classifi cation of a specifi c stage of the functional state: no fatigue, compensated, acute, chronic, overfatigue. A set of physiological indicators has been determined – heart rate, respiratory rate, fractional blood saturation level and the value of the standard deviation of the duration of cardiointervals – for which a functional dependence for calculating the integral indicator of the functional state has been obtained using the multiple linear regression method. taking into account. It has been shown that preliminary normalization of the values of physiological indicators is carried out using the Harrington membership function. The proposed integral indicator varies within 0–100 %. The reliability of the proposed regression model is statistically substantiated: all regression coeffi cients were confi rmed using the Student's t-test at a signifi cance level of 0.01, and the determination coeffi cient of 0.934 was calculated, confi rming the high level of compliance of the obtained functional dependence with the original data. The proposed integral indicator of the functional state was verifi ed for two control groups of pilots. The calculated pair correlation coeffi cients were 0.842 for the fi rst group and 0.798 for the second group, indicating a strong positive correlation according to Pearson and, consequently, the consistency of the calculated values of the integral indicator of the functional state with expert assessments. The obtained results can be used in the design and development of devices for non-invasive diagnostics of the functional state, as well as in the fi eld of clinical medicine for assessing the values of physiological indicators.

The article considers general requirements for quality control of precious metal products. It presents an algorithm for developing a quality control system for silver coins and features of its application in monitoring the chemical composition of coins with a silver content of 79.7% to 92.8% (the balance is copper). An algorithm has been developed for making decisions based on the two-parameter control results, including mathematical models for calculating the indicators of control reliability (the probability of types I and II errors). The calculation of the errors in measuring mass fractions of silver and copper (standard deviation) was performed with the required reliability (the probability of type I errors is 0.10). The article describes the dependence of the probability of type I errors on the error (standard deviation) of mass fraction of alloy components in silver coins measurement result, which can be used to justify the requirements for the indicators of measurement accuracy. Based on the criteria “Analyzed elements”, “Measurement range”, “Error”, X-ray fl uorescence spectrometers were proposed for use in the control system. The described algorithm for developing a controlsystem and its implementation in monitoring the chemical composition of silver coins will be useful to employees involved in precious metals and jewelry in specialized institutes and organizations in the manufacturing industry, banks, jewelry stores, pawnshops.

A necessary condition for obtaining high-quality food products that satisfy human physiological needs for essential nutrients and energy is continuous monitoring of the macronutrient content. The correctness of measurements in the process of such monitoring is verified by analyzing, in parallel with working samples reference materials of the composition of food products and food raw materials. The certified values of these reference materials shall be traceable to measurement standards and/or measurement results of national metrology institutes. For mutual recognition of the calibration and measurement capabilities of national metrology institutes, they must obtain equivalent results in key comparisons. The possibility of organizing key comparisons is assessed during pilot comparisons. The article presents the results of pilot comparisons in the field of measuring the nutritional value of milk powder COOMET 880/RU-а/23 with the participation of national metrology institutes of the Russian Federation, Republic of Belarus, Kyrgyz Republic and China. Samples of skim and whole milk powder were selected as the objects of comparison. The measured characteristics are mass fraction of moisture, nitrogen, protein, fat, ash, carbohydrates (lactose). Each participant in the comparison used measurement procedures, measurement instruments and equipment that ensure the highest accuracy. When assessing the uncertainty of the values of the specified measured characteristics, the participants took into account the standard deviation of the results of parallel determinations, uncertainties from the quantities included in the measurement equations, and methodological factors. The comparisons demonstrated the consistency of most of the measurement results presented by the participants. Some deviating measurement results of operationally determined quantities (mass fraction of ash, mass fraction of moisture) are due to the empirical nature of the methods used, i.e. the dependence of the measurement results on the applied drying or ashing conditions. For rational values (mass fraction of nitrogen), the discrepancies are probably due to incomplete extraction of the component from the test sample, as well as the lack of established traceability of the sample used to standardize the titrant. The results of the comparisons will be used in preparing proposals for conducting key comparisons for the purpose of mutual recognition of national standards and calibration and measurement certificates in the field of measuring the nutritional value of milk powder.