Vol 60, No 2 (2017)

The measurement apparatus in the National Primary Standard for the units of relative humidity of gases, molar (volume) fraction of moisture, and temperature of the dew/frost point, GET 151-2014, is described. The metrological characteristics of the standard and the results of the international key comparison CCT-K6 are described.

The effectiveness of boundary integral equation and grid-free methods for radial grids, as well as solutions of classical and nonclassical modeling and recovery problems for geological fields are analyzed. It is shown that, as opposed to the methods employing a variational technique and radial basis neural networks, hybrid algorithms (fuzzy neural networks, genetic algorithms, and Kalman filter) for solving identification and recovery problems are more stable with respect to noise and give positive results even with conflicting data and significant measurement noise.

A method for determining the rms deviation of the heights of surface inhomogeneities based on an algorithm for calculating the spectral density of the one-dimensional correlation function over a wide range of spatial frequencies is developed and justified scientifically. The methodological errors of the algorithm are analyzed using experimental data from studies on a test stand under production conditions.

A methodology has been developed to assess the roughness of a surface from the parameters of the curvature of peaks and valleys of the profile based on computer spectral analysis. The dependence of these parameters on the type and modes of processing, as well as on the material, is established.

An algorithm is proposed for creating an adjacent straight line from a limited number of check points of a surface profile. The effect of the number of points on methodological error when measuring deviations from straightness is examined. Recommendations regarding the selection of the number of check points are developed.

A new mathematical model for holographic and speckle interferometry is proposed which combines the existing theories of geometric and diffraction optics. New capabilities for solving a wide range of problems in applied optoelectronics and experimental mechanics for measuring the deformation of full-scale structures are examined.

Possible ways of implementing vibration test signals are described. A method for generating such signals is proposed by adjusting the amplitudes of the individual harmonic components of the vibration signal. The results of modeling are presented.

The ways of developing a reference technique in the field of measurements of the average power of optical radiation are considered. We present the converter PSM.D.T. 1 for a comparator of the average power of optical radiation in the standard of GET 170-2011 with the purpose of extending the upper level from 10^–3 to 10^–1 W, as well as a two-channel converter PSM-8.D2.T.1 as a part of the standard unit of pulsed laser radiation power GET 90-85 for equipping this standard for fiber-optic sources of radiation.

The problem that occurs when measuring time intervals is considered, for example, in the case of highprecision transmission of reference frequency signals. The technique of correlation measurements is described. A method for measuring time intervals based on a method for searching and eliminating errors associated with processing large data sets during data accumulation for subsequent averaging is proposed.

A block diagram of a device for measuring the movement of micro-objects by the heterodyne method has been developed. Analytic expressions are obtained for calculating the signal power on the photodetector, the periods of interference patterns, the measuring range, the maximum distance to the object, the minimum object displacement, the measurement accuracy, which made it possible to determine the main parameters of the device.

A formula has been derived for calculating the main magnetization curve of steels from the strength of the magnetizing field and the measurement results of the magnetization of technical saturation, coercive force, and residual magnetization. We analyzed the influence of material magnetic properties on the approximation of its magnetization to technical saturation.

Maximum likelihood algorithms for estimating parameters of a correlation matrix of clutter for adaptive allocation of signals of moving targets in multifrequency coherent pulse radar-tracking systems are synthesized. Schematic diagrams of the corresponding measuring instruments are provided.

A QRS complex detector based on the consecutive application of bandpass filtering, the Hilbert transform and an adaptive thresholding algorithm is developed. The detector is compared with existent QRS complex detectors using a model of an electrocardiogram signal contaminated by interferences of various types and intensity. The developed method of QRS complex detecting is verified using the MIT PhysioNet database of clinical electrocardiogram signal recordings.