Vol 60, No 4 (2017)

Calibration of diagnostics system sensors for vehicles, based on using the method of weighted uniform approximation of inverse transformation functions, is considered. This method is compared with the uniform approximation method on the basis of experimental data. Application of the proposed method of calibrating diagnostics system sensors for vehicular transport makes it possible to solve problems of forecasting the residual operating life of vehicle subassemblies without use of high-precision sensors.

We analyze difficulties and propose algorithms for determining robust estimates of correlation functions for random noisy signals in monitoring and control systems. Robustness conditions are satisfied by eliminating the effect of interference on the error of the estimates obtained for a useful signal, correlated or uncorrelated with interference.

The NetTestBox combined hardware–software complex, which supports measurement of IP network performance metrics, is created. The metrics are intended for estimation of the quality of Internet connections. The basic aspects of the implementation of measurements of one-way network delays in the complex are described. The selection of a network time protocol server for NetTestBox is evaluated. Results of measurements of the duration of the main components of a network delay are presented.

The structure and basic metrological characteristics of the National Primary Standard for the unit of sound pressure in air at frequencies of 2–25·10³ Hz (GET 19-2010) are discussed. Data from the international key comparisons CCAUV.A-K5 are presented. The results of the measurements at VNIIFTRI are in agreement with those of the leading national metrological institutions and confirm the reliability of the declared metrological characteristics of GET 19-2010.

Development of the concept of uncertainty of measurements is analyzed in accordance with the Guide to the Expression of Uncertainty in Measurement and Supplements thereto, the purpose of which was to expand the range of application of the concept of uncertainty. The shortcomings of the Guide to the Expression of Uncertainty in Measurement that brought about the need for its revision were examined, as well as the scientific and methodological principles on which its planned revision is based.

Existing technologies used to process streams of spatio-temporal data from a system of sensors for the purpose of selecting the most appropriate technologies for practical realization of different information measurement systems are investigated. Typical technologies for processing streams of spatio-temporal data from sensors are analyzed. Criteria for selecting a required technology for implementation in a concrete information measurement system are proposed.

The problem of parametric optimization of an optoelectronic system for measuring the coordinates of objects where there are variations in the definition and frame rate with a limitation on the rate of reading of the signal of the photodetector array is considered. It is shown that optimal values of the definition and frame frequency are determined by equalizing the estimators of the dispersions of the inter-element and inter-frame differences. It is established that the switching thresholds may be reduced through the introduction of inertia into the dispersion measurement path as a way of increasing the observation time with nearly equal values of the estimators of these dispersions of the reversal thresholds.

A measurement system based on subminiature eddy-current transducers is developed for local study of defects in aluminum-magnesium alloy plates. A modified Delianna filter is made which can greatly enhance the signal-to-noise ratio. A dependence of the response of the eddy-current transducer on flaws in the form of hidden slits and apertures inside the slabs is derived for excitation coil frequencies of 300–700 Hz.

Solutions in support of spectrally filtered measurements of signal parameters with specified metrological characteristics for low signal-to-noise ratios are obtained and tested.

Procedures for dosimetric monitoring of the radiation parameters of the latest generation of linear electron accelerators for morning and pre-therapeutic testing of plans for irradiation of patients are discussed. It is found that the deviations in the radiation yield of the accelerators lie within the international tolerance of ±2% and the width of the leakage peaks is less than 7 mm. It is shown that for intensity modulated radiation therapy, the calculated and measured values agree to within 75–100% for 95% of irradiation plans.

The limitations of using the sonic echo method for evaluating the integrity of driven concrete piles with near-surface flaws are examined. Criteria for detecting pile flaws in a compact region are obtained. It is shown that it is possible to use the multiplicative impact-echo method for determining the length of a pile with a near-zone flaw.

A method is proposed for determining the diffusion coefficient of solvents in thin porous materials with substantial anisotropy of their properties. The method makes possible direct nondestructive testing of articles of anisotropic porous materials. Problems of increasing the productivity and accuracy of the method are examined.

The results of international pilot comparisons in the field of measurements of ultrasonic power in water are analyzed. The comparisons were made on the state primary standards of the Russian Federation (VNIIFTRI) and Ukraine (DP NDI Sistema) in 2014–2016 in the radiated power range of ultrasound 1·10^–2–1 W and frequencies of 1.5–12 MHz.