articles
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№ 5(95)
31 october 2021 year
Rubric: Algorithmic efficiency Authors: Eremeev V., Ivashko A., Tsyganova M. |
All enterprises engaged in exploration activities on the territory of the Russian Federation, are facing the need to formulate tasks for the mine surveyor service and control their execution. It affects enterprise’s workflow process. Due to it, a problem of organization of efficient document processing in electronic document management systems (timely identification of documents containing mine surveying data) takes place. The article presents possible solution of this problem – automated document classification system into EDMS in the form of optional add-on for 1C:Document Management. Within the classification system creation a preprocessing script for primary document texts, including cleaning, lemmatization, stop words removing, as well as preparation of input features for the classifier were developed and implemented. Applicability of different machine learning algorithms to solution of considering classification problem was studied, the values of hyperparameters providing the highest value of the ROC AUC metric were determined. The quality of all obtained models was assessed using metrics Precision, Recall and F-measures, the stability of the classification quality to changes in the input data was investigated. The identified problem of instability of classification results was solved by building and implementing a machine learning model in the form of ensemble of classifiers. Classification model (an ensemble of clusters) was tested on the set of real documents of Gazprom nedra Ltd; classiffication quality on the test sample by ROC AUC metric was 0,91. Except the classification module itself, developed system contains the storage database for learning outcomes, function library for organization of work with the database and API interfaces allowing to process classification requests, coming from external systems. These API interfaces, in particular, implement the ability to load saved trained models, validate data coming from external systems, preprocess input text documents, train new models and assess their quality, save both trained models and the results of their testing. Also the possibility of the additional training of the models on a new data was realized. Continue... |
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№ 5(95)
31 october 2021 year
Rubric: Algorithmic efficiency Authors: Karpov D., Smirnov S., Struchenkov V. |
This article is a continuation of the article published in Journal of Applied Informatics nо.1 in 2019 [1]. In it, the problems of computer design of routes of various linear structures (new and reconstructed railways and highways, pipelines for various purposes, canals, etc.) are considered from a unified standpoint, as problems of approximating a sequence of points on plane of a smooth curve consisting of elements of a given type, i.e. spline. The fundamental difference from other approximation problems considered in the theory of splines and its applications is that the boundaries of the elements of the spline and even their number are unknown. Therefore, a two-stage scheme for finding a solution has been proposed. At the first stage, the number of spline elements and their parameters are determined using dynamic programming. For some tasks, this stage is the only one. In more complex cases, the result of the first stage is used as an initial approximation to optimize the spline parameters using nonlinear programming. Another complicating factor is the presence of numerous restrictions on the spline parameters, which take into account design standards and conditions for the construction and subsequent operation of the structure. The article discusses the features of mathematical models of the corresponding design problems. For a spline consisting of arcs of circles, mated by line segments, used in the design of the longitudinal profile of both new and reconstructed railways and highways and pipelines, a mathematical model is built and a new algorithm for solving a nonlinear programming problem is proposed, taking into account the structural features of the constraint system. In contrast to standard nonlinear programming algorithms, a basis is constructed in the zero-space of the matrix of active constraints and its modification is used when the set of active constraints changes. At the same time, to find the direction of descent at each iteration, no solution of auxiliary systems of equations is required at all. Two options for organizing the iterative optimization process are considered: descent through groups of variables in the presence of sections for independent construction of the descent direction and the traditional change of all variables in one iteration. Experimentally, no significant advantage of one of these options has been revealed. Continue... |
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№ 5(95)
31 october 2021 year
Rubric: Software engineering Authors: Glukhikh I., Glukhikh D., Karyakin Y. |
Preventing and neutralize dangerous situations tasks are relevant in the operation of complex technological objects. Complex technological objects present, in particular, in the support city systems (heat, water, energy, gas supply systems), at large industrial, mining, or processing enterprises. The development of dangerous situations at such facilities can lead to undesirable or even catastrophic consequences. The decision-making process to neutralize (prevent) an emerging dangerous situation is aimed at finding an action program that should transfer the current emergency situation into a target, standard situation. The article examines the possibility of implementing a case-based reasoning method for retrieving a solution using a neural network in order to prevent and neutralize dangerous situations at a complex technological object of city infrastructure. The authors consider the situation as a set of elements states of a complex object and the relationships between elements. To solve the tasks, the work examines two neural network architectures: a model that builds upon the multilayer perceptron and the "comparator - adder" architecture.Experiments have shown that the proposed neural network architecture "comparator - adder" showed higher accuracy than the multilayer perceptron for the considered tasks of comparing situations. The obtained result continues the well-known research in the integration of machine learning methods and methods of knowledge-based systems field. It serves as the basis for the further development of decision inference hybrid models for intelligent control of complex objects. Continue... |
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№ 5(95)
31 october 2021 year
Rubric: Software engineering Authors: Kozyrev N., Keyno P., Kvashnin V., Novikov A. |
Development of a web-resource today is a very frequent and not always simple task. Especially if we are not talking about a static one-page website, but about a dynamic web application with an unlimited number of pages, as well as the ability to withstand heavy loads, typical of such projects. To solve these problems, there are very few ready-made solutions. Of the best ones, perhaps, only WebDSL can be distinguished, but even it has a number of drawbacks inherited from the Java project implementation language, such as, for example, low flexibility, high performance costs and the need to install a java-machine. The development process was carried out using a relatively low-level C++ general purpose programming language, which saved the project from the problems that its competitors faced, ensured high interpreter performance and cross-platform system-wide. The authors described in detail the selected means of the meta-management of the access rights of the BlockSet project, as well as the syntax of their use in the declarative highly abstract subject-oriented language BML, using simple and accessible examples to demonstrate the conciseness, but the constructiveness of the selected syntax solutions. The results obtained are of great value, as they significantly simplify the further process of administering a web resource, which is also one of the main tasks of the BlockSet project. Thus, the BML language, together with the system of access rights, provides flexible, powerful, and at the same time fairly simple and understandable methods for organizing the required system, which corresponds to the project’s paradigms on flexibility and a low threshold of entry, and also significantly optimizes the development process. Continue... |
| The article is concerned with an approach to assess the economic efficiency of IT projects, which results are recommended to be used when choosing the informatization version for organizations of various types. This approach is based on the calculation of such indicators as capital costs for an IT project, the magnitude of the projected change in operating costs to ensure the functioning of the IS (information system), the growth rate in the efficiency of business processes as a result of informatization, as well as the costs to ensure the required level of information security. The analysis results of modern trends in the IS development for informatization of organization business processes are given, which made it possible to identify the main features of the solutions offered on the market. The analysis of direct and indirect costs for an IT project is shown to be rather difficult in a number of cases, which leads to inaccuracies in assessing its economic efficiency. In this case, the estimated payback period of the project (usually unreasonably short) can be exceeded many times in practice. At the same time, as a result of rapid progress in the field of information technology, the IT projects results are subjected to intense obsolescence, so long payback periods can lead to significant losses for the organization implementing the project. The consideration of the influence of the information security threats and the necessary additional funds for its provision on the forecast indicators for the economic efficiency of the proposed IT projects can significantly affect the decisions on choosing not only the configuration of the IS but the platform on which it operates as well. The article proposes an approach to determine the costs for ensuring information security, which should be considered when assessing the IT project economic efficiency. A mathematical model is described to choose an option for the tables rational placement on IS units (database servers) used by employees of various geographically detached divisions of an enterprise, which will allow reducing operating costs for this system operation. Continue... | |
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№ 5(95)
31 october 2021 year
Rubric: Researching of processes and systems Authors: Andreenkov E., Shunaev S., Skorubskiy V. |
The article discusses the main aspects of modeling suspended polymer high-voltage insulation of overhead power lines (PTL) in the COMSOL Multiphysics 5.6 software package. Analytical expressions of the mathematical model of the electromagnetic field around the insulator are given, on the basis of which a numerical solution is formed within the software package that allows you to build a model of the electric field in two-dimensional and three-dimensional space. There are three main stages of working with the program interface. At the first stage, the task of the geometric dimensions of the model and the surrounding area is considered, attention is paid to the formation of the design features of polymer insulators. In the second stage, the physical properties of the structural materials of the insulator, as well as the surrounding space, are described. The third stage is reduced to the determination of boundary conditions for solving the Poisson differential equation. Recommendations for finite element mesh density are given. A gradient picture of the distribution of the electric potential near the surface of the insulator is presented. The graphs of the distribution of the normal component of the electric field strength along the surface of the insulator are also plotted. On the basis of the obtained results, the influence of external factors on the properties of the polymer insulator is studied. A possible variant of modeling influencing factors, such as pollution and moisture, by making changes in the description of the physical properties of the insulator surface, namely by including a uniform and continuous layer with a given conductivity, is described. The distribution of the normal component of the electric field strength along the surface of the insulator with contamination is obtained. The results of modeling the electric field distribution with the presence of contamination on the surface of the insulator and its absence are summarized in the table where the electric field strength is indicated depending on the distance to the traverse. Based on the analysis of the results obtained, an assumption is made about the overestimated level of the maximum electric field on the insulators recommended by the manufacturers. The convergence of the considered models with the experimental data obtained in the course of long-term observation of the dynamics of the degradation and aging processes of the surface of polymer suspended insulators of overhead transmission lines is discussed. Continue... |
