The development of the situation around Covid-19 is an urgent problem for the whole world, and it is still not known exactly how the pandemic will develop. However, based on the data of the virus spread to date, it is possible to model the approximate outcome of the activities of humanity in the fight against Covid-19. To develop this model, we used a simulation tool-AnyLogic (Personal Learning Edition) with support for the Java programming language. This software has a large analytical functionality. When creating the Covid-19 infection model, the free version of the program was used. This model is only relevant if the pandemic continues at the same pace. There are many factors that can deviate from the presented model in any direction: early release from restrictive measures, virus mutations, forced vaccination of the population, and other measures that directly affect the main indicators of infection development. In the process of modelling the spread of Covid-19 coronavirus infection in the Kaluga region, results were obtained that reflect the rate of development of the pandemic. Thus, it is possible to identify the weaknesses of the fight against viruses and further minimize the rate of development of the disease.

Currently, one of the most pressing issues in the deployment of smart contracts is security. Concerns about inefficiency, security, and dishonest behavior are well-founded, so ignoring them when using the blockchain network to create smart contracts can lead to extremely high additional costs. The article deals with the most common tools for smart contracts auditing. The purpose of this article is to compare the most popular software tools for smart contract security analysis. Smart contracts were used for this purpose that were recognized as secure with a high degree of probability (hereinafter, for simplicity, known as secure or secure smart contracts), as well as vulnerable or simply vulnerable smart contracts. In total, 20 DeFi smart contracts from the Ethereum blockchain network written in the Solidity programming language were used for analysis.

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At the time of writing, humanity’s struggle with coronavirus infection has been going on for almost 1.5 years, but the outcome is still unknown. The SARS-CoV-2 virus significantly affects the life of every person, which underlines the urgency of the problem. To combat COVID-19, the authorities of the region take many decisions to delay and slow down the growth of morbidity. This article is aimed at studying the impact of restrictive measures imposed by the authorities on the development of the situation with a new coronavirus infection. A computer prognostic model will be used to compare the effectiveness of each solution for new virus strains and outbreaks of morbidity. Based on the model, the results of the impact of decisions and methods taken by the authorities during the pandemic on the development of the morbidity situation will be analyzed. In order to obtain statistically important data on territorial parameters, the Kaluga region was chosen, taking into account the location near Moscow, where the disease manifests itself most vividly, due to the large number of residents.