Mathematical Models of Additional Measurement Errors of Control Means

Studies have shown that under industrial conditions there is rarely a correction of the current measurement result when the influencing parameter deviates from the normalized value. The existing method of determining the additional measurement error is that in order to obtain the real value of the measurement result, the correction is calculated, which leads to the current value of indexes of control means. The correction value is determined by dividing the degree of the influencing parameter deviation by the normalized value of the additional error. This method of determining the correction is not accurate enough, since it does not take into account the nonlinear dependence of the additional measurement error on the change in the influencing parameter, as well as on the current value of the output signal of control means. To determine the real value of the measured parameter and the additional error, the method of integral-type functional is proposed. The essence of the method is in determining the difference of planes under the nominal and current parts of the static characteristic, limited by the measurement range. It is shown that the planes difference depends on the current and real values of the output signal of control means, as well as on the influencing parameter deviation. The method allows calculating the real values of the measured parameter only by the output signal of control means and the current values of the influencing parameter. The dependencies between the real value of the measured parameter, the current value of the output signal of control means and the influencing parameter deviation are established.

An efficient algorithm for simulating ensembles of parameterized flow problems

Many applications of computational fluid dynamics require multiple simulations of a flow under different input conditions. In this paper, a numerical algorithm is developed to efficiently determine a set of such simulations in which the individually independent members of the set are subject to different viscosity coefficients, initial conditions and/or body forces. The proposed scheme, when applied to the flow ensemble, needs to solve a single linear system with multiple right-hand sides, and thus is computationally more efficient than solving for all the simulations separately. We show that the scheme is nonlinearly and long-term stable under certain conditions on the time-step size and a parameter deviation ratio. A rigorous numerical error estimate shows the scheme is of first-order accuracy in time and optimally accurate in space. Several numerical experiments are presented to illustrate the theoretical results.

Controlling and synchronizing the spatiotemporal chaos of photorefractive ring oscillators with coupling

We present the control and synchronization of spatiotemporal chaos in the photo-refractive ring oscillator systems with coupling technology. First, we realize the synchronization of spatiotemporal chaos in the two photorefractive ring oscillator systems via mutual coupling by choosing a suitable coupling strength. With the mutual coupling strength enlarging, the two mutual coupling photorefractive ring oscillator systems are controlled into periodic state, period number differs on account of the coupling strength and lattice coordinates. By increasing the coupling strength, the photorefractive ring oscillator is converted into period 8, subsequently it is converted into periods 4 and 2, periodic synchronization of the photorefractive ring oscillator systems is achieved at the same time. Calculation results show that period 1 is impossible by mutual coupling technology. Then, we investigate the influence of noise and parameter deviation on chaotic synchronization. We find that mutual coupling chaotic synchronization method can synchronize two chaotic systems with the weak noise and parameter deviation and has very good robustness. Given that the weak noise and parameter deviation have a slight effect on synchronization. Furthermore, we investigate two dimension control and synchronization of spatiotemporal chaos in the photorefractive ring osillator systems with coupling technology and get successful results. Mutual coupling technology is suitable in practical photorefractive ring oscillator systems.

Using Parameter Deviation Function for Estimating the Calibration Life of Micrometers

The paper presents the results of an experimental study performed on specific measuring devices micrometers, study aimed at determining the calibration life of these measuring devices as a function of the metrological reliability, due to the internal parameter deviation. The experimental study conducted is aimed at determining the calibration life of external micrometers for 0 - 25 mm. The experimental data is obtained in the laboratory conditions and it is represented by the measuring errors, obtained for the same nominal size, experimental data being grouped in samples produced at a certain interval of time, by measuring the same dimension with a set of micrometers.The research performed on the considered set of micrometers can lead to the conclusion that the appropriate moment for performing the calibration for a specific set of measuring devices can be estimated by determining the calibration life based on parameter deviation functions, these being obtained by means of regression analysis. The algorithm for estimation of the calibration life of the measuring devices as a function of the metrological reliability can be used for determining the calibration life of the analysed measuring devices, such as to compare the estimated calibration life with the requirements set in the appropriate standards. In the case of the set of micrometers analysed, the pre-set calibration life proved to be earlier than necessary and the estimation of the calibration life by means of parameter deviation would reduce the total costs of the appropriate operation.