Vol 62, No 4 (2019)

A fast algorithm is proposed for choosing the coefficients of blur coefficients for kernel functions in a nonparametric estimate of the separating surface equation for a two-alternative pattern recognition problem. The algorithm is based on the results of a study of the asymptotic properties of nonparametric estimates of the decision function in the recognition problem for patterns and the probability densities of the distribution of random variables in classes. We compare the proposed algorithm with the traditional approach based on minimizing the estimated probability of a classification error.

We analyze the effectiveness of the qualification test method for communications satellite earth stations, implemented using a multi-user distributed measurement control system. We study the dependence of shortening the test phase on the number of organized operating sites, the technical characteristics of the spacecraft and the planned operational load of the on-board relay complex. We consider the possible increase in the commercial efficiency of a spacecraft over its lifetime.

We present application of three alternative approaches for solving the Example S4 from EA-4/02 (Calibration of a gauge block of nominal length 50 mm); see [4]. As a result, application of the alternative approaches validates usage of the standard GUM uncertainty framework; see [1]. In particular, we consider the following alternative approaches to obtain the expanded uncertainty of measurement and/or the proper coverage interval for the measurand, namely (i) GUF (GUM uncertainty framework) based on using the Guide to the expression of uncertainty in measurement [1], (ii) MCM (Monte Carlo method) based on using Supplement 1 to the Guide to the Expression of Uncertainty in Measurement – propagation of distributions using a Monte Carlo (MC) method [2], and (iii) CFA (characteristic function approach) based on using the inverted characteristic function of the optimal linear estimator of the measurand [5]. Application of the methods (i), (ii), and (iii) is illustrated by uncertainty analysis of a well-known dataset, and the results are compared. Some useful mathematical results concerning probability density functions (pdf) and characteristic functions (cf) are given in the Appendix.

We study metrological problems encountered in measuring the volume-average temperature of heated tungsten filaments. The process of heating is realized by electric currents within the temperature range 300–3000 K. The measurements were carried with the use of an improved method of thermal resistance characterized by a weaker influence of the heat losses and contact potential drops in current-supplying wires, a lower error of measurements of the resistance of filament at the initial temperature, and the possibility of taking into account the nonlinearity of temperature dependences of the analyzed resistance near or below the Debye temperature. The relative error of measurements is estimated.

The use of piezoelectric quartz crystal sorption sensors for detecting organic impurities in gases is proposed. The characteristics of various sorption coatings for quartz resonators are studied to investigate the possibility of their further use in the development of instruments for monitoring organic substances in gases. Based on the results, it is proposed to use mixed coatings: films of organosilicate sorbents and liquid chromatographic phases. High-speed instruments for monitoring organic impurities in gases ranging from micro- to macro-concentrations can be created based on such sensors.

An error-correction method is proposed for computer arithmetic logic units, in which memory duplication is executed and an algebraic linear code with minimal information redundancy is used for control. Rules for the use of coded information have been formulated for error detection during execution of arithmetic and logical operations. A procedure is proposed for the formulation of the duplication channel of arithmetic logic units due to the use of equipment intended for coding of information and the functional redundancy of the arithmetic logic units of the processor. Mechanisms are revealed that make it possible to use the functional arithmetic logic units of the processor and the monitoring equipment for the execution of primary and duplicating functions. Hardware costs are calculated for the formation of the duplication channel, and a comparative estimation is conducted of the gain in probability of failure-free operation of the fail-safe computer when using the proposed method of error correction in comparison with the majority reservation method. It is shown that the developed method of error correction, by comparison with the majority method, makes it possible to improve the probability of failure-free operation of the computer, reduce by a third the overall hardware costs, and reduce by a factor of 2.5 the expenditures for creation of the arithmetic logic unit of the processor.

The base error of the optophysical method of measuring the parameters of an air shock wave formed as the result of the explosion of an explosive charge is estimated. With the use of reference data, the process of measuring the parameters of an air shock wave by the black box method was simulated. Values were obtained for the mean standard deviation of the result of measuring the overpressure of air in the air shock wave front for various conditions (spatial resolution, frame frequency) of the video recording of the process of exploding explosive charges of various mass.

A new approach to the assessment of interfering factors that arise in the process of diversion of a flow of liquid in the weighing device of a calibration device is presented. The uncertainty budget of the calibration device in reproduction of the unit of mass and unit of volume of liquid in a flow and unit of mass and unit of volume discharge of liquid is considered for this case. The operating principle of the calibration device is based on the method of static weighing. An assessment of the sources of uncertainty is performed by a pneumometric technique, which is itself based on an experimental determination of the local characteristics of the flow of liquid.

We analyze the experimental thermograms of specimens in the form of plates of aluminum and boron nitrides heated by a laser and a freely cooled graphite sphere. It is shown that all thermograms can be referred to the linear law of thermodynamics. The linear dependence of density of the entropy production on the rate of changes in temperature is established. It is proposed to consider the rate dT/dτ as an additional variable for the density of entropy production in the linear thermodynamic law and apply this rate for the representation of the properties determined in the nonstationary thermal mode.

An analysis technique for the determination of rare-earth metals Ce, Er, Gd, La, Nd, Y in magnesium alloys by the method of atomic emission spectrometry with inductively coupled plasma is proposed. Analytical lines of elements free of significant spectral overlays and the internal standard line were chosen. The metrological characteristics of the technique were studied using model solutions and its accuracy was verified using standard samples of magnesium alloys containing rare-earth metals.