The subject of research is the development of a service for searching through user files for a given set of keywords with parameters. The available approaches to solving such a problem were studied and the most relevant one was selected. The service searches inside files with text content in order to automate the process of selecting the desired files among the entire set. Its work is based on Porter's algorithm and uses a text stemming approach in order to obtain more accurate results. Searches for the stem of a word, taking morphology into account. Performing a morphological parsing of a word, a base is found common for all its grammatical forms, cutting off suffixes and endings. As a result, the algorithm of the service allows you to search not just for the given keywords, but also takes into account their word forms, and also searches for several sets of keywords at once, each set is analyzed separately. In addition, you can specify ranges of numeric values to search for. A feature of the service is that sets of keywords are searched together in nearby paragraphs within the range of -20 to +20 words from each other, thus taking into account the context of their appearance in the text. The service ranks the found documents according to the quality of their matching search criteria. Files in basic formats are processed: doc, xls, pdf, txt. The service operates on a Linux platform under the control of the Apache web server. Free software tools were used for development.
Keywords: search engine, document analysis, stemming, Porter's algorithm, word forms, morphology, arithmetic mean of percent, web service
The main process of stratum fluid extraction in Russia is mechanized lifting. It is observed that the stock of wells equipped with electric centrifugal pumps units has grown by 50% over the past 10 years, to almost 100,000 units. Growth detected in the average time between overhauls of the oil-well stock during this period increased by 50%, to almost 800 days. Mathematical modeling becomes a tool for further improving energy efficiency and reliability. The purposes of this work is to analyze existing models of submersible electric motors and their area of operations, identify existing shortcomings and limitations, and formulate requirements for the refined model and its application potential. The results of a thermоvisional inspecting of the rotor of a submersible electric motor after long-term operation in idle mode are presented. The temperature dispersion of the rotor packages is recorded from 36.68 °C to 46.67 °C. Different packages temperatures lead to uneven changes in the active resistances of the windings, which affect the contribution of each package to the integral operating and Electromechanical characteristics of the submersible motor. For taking into account the detected effect, it is proposed to model a submersible asynchronous electric motor as an electrotechnical complex consisting of an interacting and mutually influencing set of elementary electric machines. Spatial and mathematical models are presented that take into account temperature fluctuations in individual parts of the electric motor. The results of verification of the mathematical model are presented. Its validity in the field of applicability is shown.
Keywords: electric submersible motor, ESP, rotor pack, mathematical model, thermal processes
The article discusses the work of foreign authors in the field of solving fuzzy distribution (transport) problems. To solve such problems in real conditions, it is rather difficult to formalize all parameters in the form of definite numbers, therefore, the field of solving fuzzy distribution (transport) problems attracts wide attention of scientists and experts, provoking numerous successful studies. To solve distribution (transport) problems, when considering the current state of foreign literature, the main approaches have been identified, consisting in the use of pentagonal, hexagonal, octagonal fuzzy numbers, ranking, intuitive fuzzy environment, as well as the Pythagorean approach. Now it is becoming more and more important to use inaccurate data in real transportation problems. The listed approaches to solving distribution (transport) problems give a certain effect in comparison with the existing ones, therefore it is necessary to investigate solutions of fuzzy distribution problems using modern approaches and methods.
Keywords: fuzzy transport routing problem, optimization, fuzzy methods, fuzzy numbers, heuristic algorithms, hybrid algorithms
Applied photogrammetry systems, which act as measuring instruments, are often influenced by the external environment and operating conditions, which determine the accuracy of the results. In this regard, the problem of dynamic adjustment of algorithms for these changing conditions arises. To avoid an increase in the likelihood of human error and to reduce the requirements for personnel qualifications, you can resort to the tools of intelligent systems. For these purposes, the development of appropriate components is required, including machine learning tools. This article proposes a method and procedure for machine learning of the photogrammetric algorithm based on the observation of operator actions and a system of production rules.
Keywords: inductive learning, machine learning, photogrammetry, pattern recognition, photogrammetry, forestry, pipe industry, measurement, mobile app, automation
The work was carried out due to the fact that the regulatory documents used in the design of structures operating at elevated and high temperatures do not take into account the peculiarities of the mineral composition and structure of concrete aggregates. This is a disadvantage of these documents, since the mineral composition and structure of aggregates can differ significantly even for materials of the same name, which can significantly affect the thermal changes in concrete. Due to the impossibility of experimentally investigating all the variety of concretes based on aggregates of various mineral composition and structure, a computational and analytical study was carried out in the work on the basis of existing methods for the analytical determination of thermal changes in concretes and their components. On the basis of these methods, the effect on the thermal expansion of concretes of the presence and amount in the aggregates of the most expanding minerals (aragonite, calcite, quartz, cristobalite, potassium feldspars, pyroxenes) and glass, as well as the average size of crystals composing mineral fillers, has been calculated and investigated. Considered are heavy Portland cement concretes on aggregates of limestone, dolomite, granite, syenite, diorite, basalt, diabase, broken clay brick, chamotte and slags. Based on the calculations, it has been established that the values of the thermal change in the volume of concrete, determined according to the normative document SP 27.13330.2017, coincide with the calculated values only for certain combinations of the mineral composition and structure of aggregates in terms of crystal sizes. In other cases, the actual thermal expansion of concrete may be less and more than the values obtained according to SP 27.13330.2017. The regularities of the influence on the thermal expansion of concrete of the content of various minerals and the average size of the crystals of minerals in the aggregates are established.
Keywords: thermal expansion, conventional and heat-resistant concretes, aggregates, minerals, glass, the effect of the mineral composition and structure of aggregates
The paper presents a solution to the problem of development a vector control system for an induction motor as part of an electric vehicle power plant, which ensures the maximum efficiency of the motor in various driving modes. A nonlinear mathematical model of an induction motor is used, in a coordinate system rotating synchronously with the magnetic field and oriented along the flux linkage vector of the rotor winding. The principles and methods of synergetic control theory are used to design a vector controller. The regulator provides the set speed of the electric vehicle and minimizes energy losses in changing driving conditions. The theoretical results are confirmed by computer simulation of the power plant of an electric vehicle, consisting of a storage battery, an autonomous voltage inverter, an induction motor and a car body. To simulate the power plant of an electric vehicle with the proposed control algorithms, the Simulink environment was used. The mode of execution of the speed reference of an electric vehicle was simulated in accordance with NEDC. Based on the analysis of the battery condition during the simulation of the electric vehicle's mileage, it can be concluded that the use of an energy-saving regulator is about 40% lower compared to traditional FOC systems.
Keywords: electrovehicle, induction motor, AKAR, IFOC, simulink
The article discusses the concept of a system for automatic identification and traceability of pipe production at the stage of hot rolling. The main stages of pipe production are presented. A table of selection of technological parameters has been compiled. The structure of the database for the system of automatic identification and traceability of pipe products has been developed.
Keywords: raceability, automatic identification, pipe production, hot rolled products, quality management system
The article demonstrates the problem of controlling an asynchronous motor of an electric vehicle in the acceleration mode and maintaining the speed of the vehicle at the desired value with dynamically changing torque. To solve the problem, the dynamics of the movement of an electric vehicle was described, a vector control system with direct torque control with switching the inverter keys was described, which provides a rapid change in the electromagnetic moment practically without changing the speed of rotation of the motor rotor. On the basis of the given model, the system was synthesized in the Matlab / Simulink package, and the simulation results were obtained. The synthesized control strategies ensure the achievement of the set task of accelerating and stabilizing the speed of an electric vehicle, taking into account the passport characteristics of an electric vehicle, and the stability of a closed system.
Keywords: electric vehicle, control systems, vehicle dynamics, vector control, direct torque control
The most popular methods of reliability control are considered. In this work, attention is paid to an analytical review of methods for assessing the reliability of measured parameters, their advantages and disadvantages. In the process of analyzing statistical information, the types of inaccuracies that arise and the reasons for their appearance have been established. Methods of dealing with unreliability are given using: the method of level processing, a method for assessing the rate of change of a signal, digital filtering. The solution of the problem of detecting implicit unreliability using the support vector machine is shown.
Keywords: measurement uncertainty, implicit uncertainty, time series, sensor, APCS, level processing, Kalman filter, support vector machine
This article discusses a hardware and software complex for the study of aerodynamics and electromechanical characteristics of wind turbines (WPP) with a vertical axis of rotation. The created laboratory stand makes it possible to carry out experimental studies of the developed wind power plants, to obtain the dependences of the angular speed of rotation of the rotor and the consumed electric power on the wind speed. To demonstrate the efficiency of the considered vortex-type wind turbine, the corresponding prototypes of wind turbines with a power of 0.2 kW and 1.2 kW were designed and assembled, and their full-scale tests were carried out. The developed software makes it possible to carry out numerical simulation of the motion of a wind turbine with an unsteady undisturbed wind flow, taking into account the mass-inertial characteristics of the installation and the nature of the moment of resistance to the rotation of its rotor. Experimental and numerical results obtained using the developed hardware-software complex are presented and compared. These results indicate the possibility of using such a complex as an effective tool for the development of wind turbines with a vertical axis of rotation.
Keywords: wind power plant, experimental research, software and hardware complex, numerical modeling, numerical methods of dynamics of continuous media
The paper is devoted to the analysis of methods of adoption of satellite observation data in order to identify the required information used in the development and verification of mathematical models of hydrodynamics and biological kinetics of shallow water reservoirs. For the information accumulation, we consider the use of remote sensing data. The aim of the paper is to identify the best implementation method for software tools in order to improve the quality of assimilation of date of satellite sensing of the Earth relating to hydrobiological processes in a shallow water reservoir. The results of the work indicate the clarity and relevance of the use of high-tech methods for filtering ERS images. The modern methods of accentuation of contours of objects based on discontinuities in the brightness of a halftone image, used in real time or time close to it, have been considered, and their algorithms have been briefly described.
Keywords: mathematical modeling, shallow water reservoir, satellite sensing data, filtering methods, Kirsch, Sobel, LoG, LBP, operator, recognition, contour
The article deals with the representation of spatial data in the framework of a metamodel. The metamodel is supplemented with a subsystem for evaluating data quality. Descriptors for a particular set of spatial data are provided.
Keywords: meta-model, quality of spatial data, set of descriptors evaluation, quality assessment
The problem of increasing the coding and decoding speed of Reed-Solomon codes (RS-codes) is considered. The implementation of the Open JPEG encoding system library was chosen as a base implementation for comparison. This task is considered for an x86-64 environment. The paper proposes ways to improve performance both when using a standard set of instructions and when using vector instructions from the SSSE3 and AVX2 sets. A technique for comparing the speed of encoding / decoding RS-codes is described using the example of the developed library and the basic implementation in Open JPEG. An experimental study of the relationship between the parameters of RS-codes, the encoding / decoding rate, and the set of instructions used is carried out. It is shown that for any RS-code it is possible to significantly increase performance even on a standard set of instructions. A method is proposed for the dynamic selection of the encoding acceleration method depending on the instructions supported by the target computer and the parameters of the used RS-code.
Keywords: anti-noize coding, Reed-Solomon codes, speed, vector instructions
The article considers the process of digitalization of the higher education system based on cognitive methodology. Based on the method of cognitive maps, the structural and functional aspects of the formation of a digital university in the context of the transition to a digital economy are visualized. The basic elements that determine the process of transition to a digital university (creation of a digital educational environment, formation of digital competencies, management based on a database, ensuring information security) are presented. It is determined that in the process of transition to a digital university, changes are systemic in nature, and affect management, educational, methodological and research practices, qualification requirements for all subjects of the educational process, changes in the body of technologies, methods, approaches and tools.
Keywords: cognitive model, cognitive map, digitalization, higher education system, digital university
The article offers schemes and models that allow using formal parameters and procedures to expand the capabilities of cognitive modeling and increase the level of adequacy of decisions made based on the results of modeling. The paper presents various variants of modeling schemes, which allows the researcher to perform a more versatile analysis of the system, including the analysis of dynamic effects, as well as the selection of parameters of control actions that provide the desired level of system response.
Keywords: dynamic influence, control, simulation, formal cognitive model, formal neurocognitive network of f-euroconcept