The task of the traveling salesman, which is to find the shortest or least costly circular route, is one of the most common optimization problems that need to be solved in various fields of practice. The article analyzes and demonstrates various methods for solving this problem using a specific example: heuristic (the nearest neighbor method, the most profitable neighbor method), metaheuristic (evolutionary algorithm), methods of mathematical programming. In addition to classic exact methods (which are difficult to use for large-scale tasks based on existing software) and heuristic methods, the article suggests using the innovative features of the commercially available MS Excel software using a meta-heuristic base. To find the optimal solution using exact methods, the Excel (Solver) software package was used, as well as the specialized GAMS software package. Comparison of different approaches to solving the traveling salesman problem using a practical example showed that the use of traditional heuristic approaches (the nearest neighbor method or the most profitable neighbor method) is not difficult from a computational point of view, but does not provide solutions that would be acceptable in modern conditions. The use of MS Excel for solving the problem using the methods of mathematical programming and metaheuristics enabled us to obtain an optimal solution, which led to the conclusion that modern tools are an appropriate addition to solving the traveling salesman problem while maintaining the quality of the solution.
The article describes methods of construction of predictive models for classifying customers based on their churn from the company for the example of a mobile operator. There are roles and tasks of customer analytics for understanding the business behavior of customers. The specificity of customer churn for companies associated with a subscription and transactional business model, involving regular customer payments is discussed, and the main reasons for churn are shown. Particular attention is paid to the analysis of forecasting methods based on classification methods. Here we discuss the forecast models based on the decision tree method and the Bayesian network. The decision tree method is basing on the C5.0 algorithm. The Bayesian model is constructed for a Naive and Markov structure. Customer service has become a key factor in the customer churn in all three models. A comparative analysis of the models was conducted based on indicators AUC and Gini. The decision tree model showed the best results. Moreover, the decision tree model shows the reasons why the customer can leave the company and give information for an individual approach to each customer. SPSS Modeler was used as a tool for building models.
Abstract. Problem. The operation of transport systems of a large city must ensure a continuous flow of passengers. The subway occupies a special place in the city's transport system. The constant increase in the loading of the subway not only worsens the conditions of passenger transportation, but also shortens the service life of the rolling stock and negatively affects the reliability of its operation. In the future, this may cause failures of the rolling stock, which means work failures. The main factor in the development of subway systems is passenger traffic, which determines the development of the subway network, the capacity of technical equipment, the number of vehicles, the size of depots and vehicle repair plants, and the time of repair with the least economic losses. Thus, one of the urgent tasks of the functioning of transport systems is the creation of an automated system of mass passenger service, in particular in the subway. Goal. The tasks of this study are the analysis of the subject area, the design of the information system according to the task, the selection of the necessary tools for this development, and the methods of software implementation. Analysis of passenger flows using an automated system will allow to solve many problems of design, operation, and planning of metro work, will allow to reduce the time for passenger service and optimize passenger flows. Methodology. Research methods are the methods of mass service systems. Results. The creation of a functional model will make it possible to develop a software product for the analysis and assessment of public transport passenger traffic. Originality. Practical value. The software product created on the basis of the developed functional model will enable the user not only to analyze, but also to optimize the work of both existing and future metro stations.
Problem. Today, performance testing is an integral part of the web applications quality assurance whose performance failures and performance issues affect the business of their owners. Goal. The goal of the work is to generalize approaches and methods to improve the quality of web applications and develop recommendations for improving performance testing using open source tools. The object of research is the processes of testing web applications. The subject of research is the approaches, methods and tools of performance testing. Methodology. The study identified the impact of software performance testing on its quality and its main types, namely load testing, stress testing, volume testing, stability testing. The main stages of performance testing and their content were identified. To implement modern automated testing technologies, the advantages and disadvantages of the most popular tools for testing performance in the modern IT market and continuous visualization of their results were analyzed and identified. The following factors should be considered when selecting a performance testing tool: compatibility, scalability, clarity, and monitoring. Time series databases and visualization tools are used for continuous monitoring of test results together with testing tools. Results. During the practical implementation of the research results, the goals of different types of performance testing, indicators of normal operation of the system without exceeding the permissible limits, test scenarios and test results were identified. Visualization of test results in JMeter is shown and a board for continuous real-time visualization is created. Originality. The originality of the study lies in unlocking the potential of open source tools for testing the performance of web applications and visualizing its results. On the basis of comparative analysis the spheres of application of tools for performance testing are substantiated. Practical value. The practical value lies in the development of methodological bases for testing the performance of web applications in real time on the example of the connection of tools Jmeter – InfluxDB – Grafana.
The Workflow system is an effective solution to the task of optimizing information flow in the electronic publishing system, which can reduce the number of errors and optimize the process of publishing articles. The purpose of this article was to create a methodology for developing an information site for web publishing. To achieve the goal of the research, scientific methods of generalization, classification, deduction and analysis were used. A problem-solving tree has also been created. The ultimate goal of overcoming this problem is the development of an information site with Workflow support. The study outlines the general structure of sections and subdivisions of the information site. In the context of this article, a methodology was developed to support the process of publishing articles on an information site based on the use of a modern content management system. For this purpose, the key criteria for a basic decision-making model for choosing a content management system were proposed and a rating of free content management systems was given. As a result of the analysis of the proposed criteria, it was concluded that the Joomla tool environment should be used to support web publishing processes. The paper compares the components of the Workflow organization on the information site. An algorithm for selecting a component for organizing the Workflow has been created. In order to create a site with Workflow support for publishing articles, the stages of development were planned, a list of criteria, based on which the development should be carried out, was proposed and a structural diagram for creating such site was given. The limitations of the created methodology for the development of an information site, which may arise in the process of practical implementation and adoption of relevant management decisions, are considered. The practical result of the work is recommendations for web developers to create an information site with Workflow support for publishing articles
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