Informational uncertainty of measuring instruments

Recently, there has been a revival of interest in the use of the information approach in the theory of measurements. Unlike the traditional approach, information theory does not evaluate error or uncertainty, but entropy and the amount of information. This article analyzes a number of recent publications that develop ideas for the information approach. The limitations and disadvantages of both the entropy approach and the concept of uncertainty are indicated. As a compromise solution, it is proposed to use a criterion based on the Bongard’s uncertainty and useful information. The concept of information uncertainty is proposed, which is estimated by the amount of negative useful information, that is, misinformation introduced by the measuring instrument. Some methods for calculating information uncertainty are described. The problems of using the uncertainty approach are noted. This approach does not imply the use of such a generalized characteristic of measuring instruments as an accuracy class. The article proposes an analogue of the accuracy class in the form of relative informational uncertainty, expressed as a percentage. This will make it possible to evaluate the quality of the measuring instrument by a single parameter, the calculation of which requires a minimum of computational operations.

Експериментальне визначення стану текстильних матеріалів десантної парашутної системи Д-5 серії 2 після тривалого зберігання. Повідомлення 2. Статистичні характеристики результатів вимірювання показників строп основного парашуту

The subject of the article is the analysis of the array of experimental data of loading and elongation at break of the slings of the main parachute landing parachute systems D-5 series 2 1973 and 1974 years of manufacture after long-term storage with zero (inexhaustible) resource. The current article attempts to determine the ratio of external factors related to the natural factors of aging of polymers, and internal, due to errors in the measurement process, based on statistical analysis of measurement results. Objective: to determine the degree of influence of internal and external factors on the process and result of measuring indicators. The following methods and equipment were used. An improved method of spot sampling of the samples under study of landing parachute systems D-5 series 2 for laboratory studies to determine the load at break and elongation at break of the slings of the main parachute. Measurements were performed on a machine of bursting brand ИР 5047-50M2C, accuracy class - 0.5 for the measurement range from 0.5 kN to 5 kN. The volume of the party was 25 parachute systems, only 250 elementary tests. The array of empirical data was processed by mathematical and statistical methods of the software package Descriptive statistics on the add-on of MS EXCEL Analysis Package. The following results were obtained. The relative error of the results of load measurement when breaking the slings of the domes of parachutes of 1973 production was ± 5.0%, for parachutes of 1974 production - ± 3.8%. The relative error of the results of measuring the elongation at the break of the slings of the domes of parachutes of 1973 manufacture was ± 2.9%, for parachutes of 1974 manufacture ± 3.3%. Given that the measuring instrument has an error of ± 0.29% in the passport, which can be considered systematic, the overall level of uncertainty is acceptable for conventional measurements in engineering. Conclusions. The main factors of accidental errors in the process of measuring the load at break and elongation at break of the slings of the main parachute are external factors due to the state of the cord structure and changes in the internal structure of the polymer.

Use of High Performance Liquid Chromatography in the Analysis of a New Substance VMA-10-18

Introduction. Quinazoline derivatives have a wide range of pharmacological properties, which makes this group quite unique among other classes of heterocyclic compounds. Substance VMA-10-18, which has cerebrovasodilating, antidepressant, anxiolytic and nootropic properties, may become a promising new drug. In this regard, an urgent task is to develop methods for standardizing this substance.Aim. Development of a method for the quantitation of related impurities of a new biologically active substance VMA-10-18 (Quinazophene) by HPLC with subsequent statistical processing of the results.Materials and methods. To develop the conditions for chromatographic analysis, was used a highly purified substance 3-[2-(4-methoxyphenylamino)-2-oxoethyl]-quinazolin-4(3H)-one, as well as its related impurities: impurity I (unsubstituted quinazolin-4(3H)-one) and impurity II (4-methoxychloroacetanilide). Test solutions were prepared using volumetric glassware of accuracy class 1. Ethyl alcohol 95 % was used as a solvent. Chromatography was performed using a Dionex UltiMate 3000 system (Dionex, United States) with a spectrophotometric detector. The analysis was carried out at a wavelength of 231 nm. Data collection and processing was carried out using the Chromeleon v.7 system. A mixture of acetonitrile and orthophosphoric acid was used as a mobile phase. The analysis was performed in an isocratic mode. The validation of the developed method was carried out taking into account the requirements of the State Pharmacopeia of Russian Federation XIV edition and the recommendations of the ICH.Results and discussion. The optimal conditions for chromatography of the VMA-10-18 substance and its impurities have been developed. It was found that for a clear separation of the peaks of the substance and impurities among themselves, the mobile phase should contain acetonitrile and orthophosphoric acid in a ratio of 80 : 20. The specificity of the method was determined by chromatography of ethyl alcohol in order to exclude its influence on the analysis results. The linearity and correctness of the method were determined at 7 levels of concentration of impurities of the substance. The correlation coefficient has exceeded 0.99. Also, the free term of the linear dependence equation (a) for both impurities was less than its confidence interval (Δа), which proves the absence of a systematic error of the method. When determining the "Convergence" indicator, the calculated relative standard deviation did not exceed 2 %. When determining the intralaboratory precision, Student's t-test and Fisher's F-test were calculated. Both indicators met the stated requirements.Conclusion. A method for the quantitative determination of impurities in the VMA-10-18 substance by HPLC has been developed and validated.

Mechatronic Control Devices for a Modern Ship’s Magnetic Compass

One of the disadvantages of existing main magnetic compasses (МС) is the presence in their readings of an error from pitching due to the influence of centripetal and tangential accelerations when the MC is placed at a certain distance from the center rocking of the ship. This error can be unacceptably large, especially when using the compass in high latitude environments. This effect can be compensated by using a gyroscopic angular rate sensor (ARS), which measures the angular yaw rate of the ship. The work is devoted to the results of research and simulation of two correction system, which is introduced into the measuring circuit of the MC. Each of the correction systems presented in this work can be considered as mechatronic control device for a modern MC, one of them is positional, and the other is according to the angular yaw rate of the ship. The paper shows the advantages and disadvantages each of systems. So, a feature of the positional correction system is the need to use ARS of a tactical accuracy class (for example, a fiber-optic gyroscope). At the same time, the yaw rate correction system makes it possible to use a cheap micromechanical gyroscope (MMG). Despite the use ARS of various accuracy classes, both proposed correction systems allow achieving similar results, which leads to an obvious conclusion about the advisability of using the correction system with MMG, which allows to significantly reduce the cost of the MC, as well as to reduce its weight and dimensions.

DETERMINATION OF THE COMPRESSIVE STRESS OF A RAIL USING THE EFFECT OF ACOUSTOELASTICITY AND STRAIN GAUGE

A method for monitoring the compression stress in a rail and a sample made of steel 20 using the effect of acoustoelasticity and strain gauge has been developed. Wire load cells were pasted to the opposite sides of the rail and the sample. Measurements, recording and processing of strain gauge information was carried out by a certified microprocessor strain gauge system MMTS-64.01 with accuracy class 0.2. To control the compression stress, the developed microprocessor-based ultrasonic system “Akusto-1” was used, which operates on the basis of the acoustoelasticity effect. The angle of input of ultrasonic vibrations, equal to 18°. This allowed to excite longitudinal, transverse and transformed waves in the object. Compressive stresses in the rail and steel sample were carried out by 250-ton loading machine “PSY-250”. Longitudinal and transformed ultrasonic waves were used to control compressive stresses. A comparative analysis of the experimental and calculated dependences of compressive stresses on the load obtained by acoustic, tensometric and computational methods is performed. The reliability of the experimental and calculated results was controlled by a certified microprocessor strain gauge system MMTS-64.01.

Forest Land Cover Mapping at a Regional Scale Using Multi-Temporal Sentinel-2 Imagery and RF Models

Over the last several decades, thanks to improvements in and the diversification of open-access satellite imagery, land cover mapping techniques have evolved significantly. Notable changes in these techniques involve the automation of different steps, yielding promising results in terms of accuracy, class detection and efficiency. The most successful methodologies that have arisen rely on the use of multi-temporal data. Several different approaches have proven successful. In this study, one of the most recently developed methodologies is tested in the region of Galicia (in Northwestern Spain), with the aim of filling gaps in the mapping needs of the Galician forestry sector. The methodology mainly consists of performing a supervised classification of individual images from a selected time series and then combining them through aggregation using decision criteria. Several of the steps of the methodology can be addressed in multiple ways: pixel resolution selection, classification model building and aggregation methods. The effectiveness of these three tasks as well as some others are tested and evaluated and the most accurate and efficient parameters for the case study area are highlighted. The final land cover map that is obtained for Galicia has high accuracy metrics (an overall accuracy of 91.6%), which is in line with previous studies that have followed this methodology in other regions. This study has led to the development of an efficient open-access solution to support the mapping needs of the forestry sector.

Impact of Postgraduate Students Dropout and Delay in University: Analysis Using Machine Learning Algorithms

Cost of education and economic background are some factors that influence student dropout from postgraduate studies. However, high dropouts do not affect the students only, but also impact university revenue. This research analyzes various literature on machine learning algorithms and applies suitable algorithm to produce a prediction model. This study indicates that decision tree and Random Forest algorithms have better accuracy, class recall, and class precision than Naïve Bayes. Therefore, the prediction model uses the Decision Tree algorithm to provide various approaches to maximize revenue in universities. The findings indicate high dropout rates negatively impact university revenue, while low rates influence revenue positively. Other aspects like grants received by students, the number of research publications, anddegree level also positively or negatively impact revenue if the dropout rate is medium. A complete understanding of this prediction model can identify and minimize the risk of early withdrawal or delayed graduation and improve revenue generation by universities.

Hybrid approach redefinition-multi class with resampling and feature selection for multi-class imbalance with overlapping and noise

Class imbalance and overlapping on multi-class can reduce the performance and accuracy of the classification. Noise must also be considered because it can reduce the performance of classification. With a resampling algorithm and feature selection, this paper proposes a method for improving the performance of hybrid approach redefinition-multi class (HAR-MI). Resampling algorithm can overcome the problem of noise but cannot handle overlapping well. Feature selection is good at dealing with overlapping but can experience a decrease in quality if there is a noise. The HAR-MI approach is a way to deal with multi-class imbalance issues, but it has some drawbacks when dealing with overlapping. The contribution of this paper is to suggest a new approach for dealing with class imbalance, overlapping, and noise in multi-class. This is accomplished by employing minimizing overlapping selection (MOSS) as an ensemble learning algorithm and a preprocessing technique in HAR-MI, as well as employing multi-class combination cleaning and resampling (MC-CCR) as a resampling algorithm at the processing stage. When subjected to overlapping and classifier performance, it is discovered that the proposed method produces good results, as evidenced by higher augmented r-value, class average accuracy, class balance accuracy, multi class g-mean, and confusion entropy.

Relationship between the characteristics of machine parts and parameters of technological equipment

The aspects of the substantion of the selection of parametera of CNC metal-cutting machines are considered on the basis of their relationship with the technical characteristics of the manufactured machine parts that make up the regional data bank. A new approach to grouping parts using cluster analysis is proposed. For the processing of eight groups of parts in the form of bodies of revolution, the parameters of machine tools are substantiated (the number and composition of shape forming coordinates, the size of the working space, the structure of technological operations, the accuracy class according to GOST 8-82E, as well as the accuracy and roughness of the processed surfaces obtained depending on workpiece material. Keywords: machine tool, numerical control, part, shape forming coordinate, workspace. [email protected]

The principle of creating a "smart" electricity meter in electric traction networks with stochastic electromagnetic processes

Voltage and current are sharply variable random (stochastic) processes in traction networks of DC electric transport systems. As a result, electronic and hybrid electricity meters used in electric systems measure electric power with a large relative error that significantly exceeds that of their accuracy class. In this paper the principle of developing smart meters for accounting the electricity transmitted from traction substations to electric rolling stock through a traction network is proposed. Proposed ideas are developed on the basis of the random processes correlation theory. The meter operates in real time and monitors not a set of realizations of random voltage and current processes, but their deterministic characteristics, that is, time functions of mathematical expectations and variances which make up the background of its operating principle. The experimental implementation of the proposed principle has been conducted in the feeder zone of an A-B section of the GisDnieper Railway of Ukraine, where registration and processing of realizations of stochastic voltage and current processes obtained in real operation mode has been done. The ratios obtained for active and reactive power can be applied not only for traction power grids, but also for electric networks of external power supply of DC electric traction systems as the basis for the “smart meter” design.