перетворення Фур’є

Technique for Defining the Optimal Parameters of Moving Window at Vibration Accelerometer Signal Processing

This paper presents a technique for defining the optimal parameters of a moving window when processing the signal of a vibration accelerometer installed on a ball drum mill as part of the automation system. Time series signals of the vibration acceleration have been synthesized based on the experimental data of frequency spectrums with the application of the inverse Fourier transform. The lower and upper limits for the moving window size have been defined.

Constructing solutions for two-dimensional quasi-static problems of thermomechanics in terms of stresses for bodies with plane-parallel boundaries

A methodology to construct solutions for two-dimensional quasi-static thermomechanical problems for bodies with plane-parallel boundaries (2D-QS thermomechanical problems) is proposed.  This approach begins with selecting equations for the plane quasi-static thermoelasticity problem in terms of stresses.  The methodology approximates the distribution of non-zero stress tensor components through the body's thickness using cubic polynomials, with coefficients expressed in terms of integral characteristics of the stress tensor components over the thickness variable and the

Extending the application domain of the model order reduction method in calculating the electrostatic field

A problem of determining the electrostatic field formed by a set of charged electrodes has been considered.  The details of the approximate solving of the Dirichlet problem have been given for the Laplace's equation in a substantially spatial formulation based on the use of the model order reduction method.  The mathematical models have been improved and the problem of calculating the electrostatic field has been simplified, taking into account the present symmetry of electrodes positioning in electronic optics systems.  For the eighth-order abstract group, three independent structures of t

Відновлення форми джерела розсіювання, поле якого спотворене шумом

Розглянуто задачу відновлення форми джерела розсіювання в однорідному середовищі. Вхідними даними цієї задачі є інформація про набір приймачів і виміряне ними розсіяне поле, спотворене шумом. Показано, що для її розв’язання необхідно відновити функцію двох змінних за її радоновим образом. За формою джерела розсіювання в роботі запропоновано новий підхід, за яким немає необхідності знати інформацію про далеке поле, а також про координати та кут, під яким джерело сигналу знаходиться відносно системи приймачів.

Comparison results of sensing nqr using continuous wave and pulsed nqr - fft spectrometers

Traditional continuous wave methods of observation of NMR and NQR is now almost completely superseded by pulse Fourier transform spectroscopy. Compared with the method of continuous frequency scanning, pulse Fourier transform spectroscopy has advantages, which consists in a high sensitivity, increased spectrum resolution, much less distortion of the lines shape. In addition, pulse spectroscopy provides a reduction in the time of observation compared with stationary methods.