DOI: 10.25136/2644-5522.2020.2.32996

Abstract: The subject of the research is the problem of monitoring and troubleshooting in distributed high-load systems. The most common mistakes in design and development, methods of their forecasting and solutions are described. In this article, the author describes the most popular tools that are currently used in the development of high-load systems and the main mistakes when working with them from a developer's point of view.This article describes a set of tools, the implementation of which can significantly reduce the time spent searching for vulnerabilities, describes the difficulties in choosing a set of metrics technologies - ELK / EFK, describes their advantages and disadvantages. The analogs of the tools used are analyzed in detail. The main conclusions in the work are:- the need to develop the infrastructure for monitoring the system from the beginning of the project development, due to which it is possible to correct the high complexity of the project at the stage of its development.- it is necessary to use the most popular tools for which there is a large amount of information in open sources, for example, on the Internet. This approach will reduce the time spent on fixing errors that can be caused by a specific set of tools.- the company needs not to save on highly qualified personnel, which in the future will save a lot of time on fixing problems, reduce the time for developing new functionality and allow spending a minimum of time to support and test the already developed functionality.- when analyzing problems, it is worth paying attention to public resources in which other companies, most likely, have already solved similar problems. For example, the Facebook company has been dealing with the monitoring problem for a long time and has developed a large number of tools to solve this problem. They also collect a large number of system records for analyzing the behavior of the system under any circumstances.

DOI: 10.25136/2644-5522.2020.2.34076

Abstract: The relevance of this article lies in the fact that today's databases are the basis of numerous information systems. The information accumulated in them is extremely valuable material, and today database processing methods are widely spread in terms of extracting additional methods, knowledge from them, which are interconnected with generalization and various additional methods of information processing.The object of research in this work is relational databases and DBMS, the subject of research is the features of their use in applied programming.In accordance with the set goal, it is necessary to solve the following tasks:1) to consider the concept and essence of a relational database;2) to analyze the problematic aspects of relational databases in modern conditions. Relational databases are among the most widespread due to their simplicity and clarity at the creation stage and at the user level. It should also be noted that the main advantage of RDB is its compatibility with the main query language SQL, which is intuitive for users.Nevertheless, with all the variety of approaches, there are still some canons, violation of which greatly affects both the design of the database and its operation. For example, the problem of database normalization is very relevant. Neglecting normalization makes the database structure confusing and the database itself unreliable.Promising directions include the development of queries to a relational database using heuristic methods, as well as the method of accumulating previously optimized queries with subsequent verification of the derivability of the current query from the accumulated ones.Finally, a very slow decline in relational databases is probably happening. While they are still the primary storage medium, especially in large enterprise projects, they are gradually being replaced by non-relational solutions that will become the majority over time.

DOI: 10.25136/2644-5522.2020.2.33914

Abstract: This article examines the problem of numerical simulation of interaction between the gaseous sulfur dioxide emitted by road transport and fog in the conditions of high humidity. For this purpose, the author applies a multi-factor two-phase mathematical model, which takes into account the dynamics of turbulent main phase, dynamics and kinetics of the multi-sectional droplet phase, presence of thermal inconsistencies formed as a result of direct and diffused solar radiation in various ranges, diffusion of sulfur dioxide, and its absorption by the fog droplets. The article carries out a numerical calculation of the corresponding task within the modeling system of environmental processes AirEcology-P, which allows generating the optimal calculation code for a particular mathematical model. The proposed complex mathematical model that descries interaction between the emitted sulfur dioxide gas and the fog droplets is new; it specifies the calculation of the kinetics of droplet phase based on consideration of the additional factor of droplet fusion characteristic to fog. The submodel of the droplet phase was tested in the numerical simulation (the results were compared with the data of direct Lagrangian modeling of the composite of 1,000 droplets), indicating decent accuracy results. The article obtains the results of numerical simulation of interaction between the emitted SO2 and the droplets. The author demonstrates the self-cleaning ability of the atmosphere, the degree of which correlates with the initial concentration of the smallest droplets and the height from the surface.

DOI: 10.25136/2644-5522.2020.2.34102

Abstract: The simulation model of the column string-emulsion reactor previously suggested that the temperature does not change on the height of reactor and over time is consistent. The assessment of temperature changes in the reactor requires the knowledge on the amount of heat necessary to heat up the particles, absorbed or emitted in the course of chemical reactions, as well as the speed of heat transmission in space. The possibility of calculating these parameters for each floating particle in online regime is limited by the operating speed of the computer system. For accelerating the calculations, the author creates the database of these parameters for all substances involved in the reactions. In these circumstances, enthalpies and entropies were expressed in through the specific thermal capacity calculated based on the fifth degree polynomial. The coefficient values of the polynomial and phase transitions were taken from the reference books. The article provides an algorithm in form of the logic diagram for calculating the specific enthalpy of the particle. Based on the developed algorithm, the author creates the software that allows calculating thermodynamic functions. The interaction between the classes are demonstrated in the UML class diagram. The research presents the calculations of specific enthalpy and entropy for substances in the interval of temperatures of 298-1850 K. Variations of the values of enthalpy and entropy at the temperature of 1700 K compared to the reference values do not exceed 1.2 %.

DOI: 10.25136/2644-5522.2020.2.34099

Abstract: The object of this research is the service systems that receive a stream of requests on their input, which represents a range of mutually dependent operations of the “finish” – “start” type. The time of conducting separate operations is a random variable, and the delivery itself requires the use of one or several types of resources. It is suggested that there are timeframes for processing the request. The goal of this research is to develop the database structure that would allow storing information on the incoming projects, operations, mutual dependence, used resources and specialists. The design of logical structure of the database was carried out using the methodology “essence – link”, which determines the data values in the context of their correlation with other data. The analysis of specificity of the object of research revealed a range of requirements submitted in the database. Leaning on these requirements along with considering normalization of relations used in the theory of relational databases, the author designed the universal structure from the perspective of its application, support of the analysis of the scheduling process, and the entirety of peculiarities of the object of research. Such database structure can be used in different fields that allow decomposition of the project into multiple separate interdependent tasks, not requiring major modifications. The article provides the examples of using the database for information systems in construction sector, as well as for the development of IT projects.