Publications

Aims. Solar flares as a dangerous phenomenon of space weather can produce a huge number of X-rays that affect the Earth's atmosphere and can accelerate atomic particles (mainly protons) to very high speeds. These high-energy particles pose danger to space technology and manned missions. What is very important is the fact that electrostatic discharge is a source of powerful interference of an electromagnetic nature that affects negatively the functioning of individual parts and entire systems. Thus, the purpose of new solutions is to deliver recommendations to minimize the negative phenomena and hazards caused by space weather. Methods. This paper proposes original approaches for quickly constructing a picture of the spreading of currents over the surface of a spacecraft due to electrification. The key point of the first approach is constructing a limited area to calculate the spreading of currents. The calculation of transient currents will occur only in this user-designated EMS area, without affecting the rest of it. The main disadvantage of this method is that third-party software is required for its implementation. The paper also develops new reduced computational schemes for a system of integrated differential equations based on Euler's methods. Results. With the help of the new computational schemes, the time to calculate unknown quantities in a local area designated by the user has been reduced by several orders of magnitude, compared to the calculation of unknown complete models. The article presents conclusions on the  new computational schemes, with their construction complexity indicated. The adequacy and accuracy of the new computational scheme is confirmed by a practical example.

The development of modern IT tools is a key vector of development in the management of natural hazards and geosciences. Thanks to the creation and implementation of geographic information systems (GIS) and technologies, monitoring of the area is greatly facilitated and the accounting of natural resources becomes streamlined. Geoinformation systems allow to take into account the social and environmental situation, accurately determining the qualitative and quantitative characteristics, structure, and location of objects. This allows the authorities at different levels to develop social infrastructure most effectively and correctly locate objects of it.In addition, geographic information systems are very effective for determining the location of an object. The requested information is provided in the form of detailed maps with additional details in texts, graphs, and diagrams.GIS tools are not a single program, but a package of programs, they have different interfaces and capabilities of working with data. Usually, the one that is best suited for the task is selected from this software package. An example of the choice of effective tools and related research in work with BigGeoData are presented in the article about aero monitoring use case.

We can observe self-organization properties in various systems. However, modern networked dynamical sociotechnical systems have some features that allow for realizing the benefits of self-organization in a wide range of systems in economic and social areas. The review examines the general principles of self-organized systems, as well as the features of the implementation of self-organization in sociotechnical systems. We also delve into the production systems, in which the technical component is decisive, and social networks, in which the social component dominates; we analyze models used for modeling self-organizing networked dynamical systems. It is shown that discrete models prevail at the micro level. Furthermore, the review deals with the features of using continuous models for modeling at the macro level.

In my opinion, it is necessary to have only three basic courses: differential and integral calculus, basics of algebra, and probability theory with mathematical statistics.

The field of Information Communication Technology (ICT) is a rapidly developing and expanding arena. With the expansion of it, the need for specialists, skilled in ICT, is in high demand. The recent outbreak of Covid-19 virus has reshaped the current labor market for people with IT skills. People with tech skills in place need to evolve under new circumstances as the business where they work faces huge changes influenced by remote work. In this study, we set out to investigate what challenges may rise in IT-students skill sets and competences after the Covid-19 pandemic due to remote work, lack of formal and informal face-to-face communication and other factors. Further the paper analyzes how the IT specialists feel in a changing environment, and recommends how businesses and people need to change themselves to adapt to the Covid-19 effects based on the analysis and how to grow in their future skills.

A new pair routing algorithm for transmitting messages in multiprocessor systems and networks-on-chip based on circulant networks of arbitrary dimension is proposed. It allows using all reserve shortest paths in the presence of destructive factors (deadlocks, livelocks, starvation, failures) at the nodes and channels of the communication network. A distinctive feature of the proposed algorithm is the absence of using the routing tables with fixed shortest paths when message is transmitted. It becomes possible to determine the set of the shortest paths for routing due to the relative addresses of destination nodes based on a parametric description of the network. Estimates of the number of reserve shortest paths are obtained, and an effective algorithm for using these paths to prevent dynamic topology changes and network congestions is proposed. To reduce the required memory in networks-on-chip with a circulant topology, we proposed a version of the routing algorithm for two-dimensional optimal circulants. We experimentally found the minimum number of reference nodes (nodes containing mapping tables) for them and estimates of memory for mapping tables, as well as the average path length for the routing algorithm using the reference nodes.

This article presents generalized model of collaborative actions, during which participants create, modify, and estimate digital objects. Such activities can be observed in numerous network communities. A prominent example is the repository of lesson scenarios of Moscow Electronic School (MES). The combination of methods of agent-based modeling and network analysis is used in the work. Using NetLogo environment in the frames of the model, an artificial community has been developed, where teachers-agents interact with scenarios-agents. Teacher-agent determines whether there are potential scenarios in his environment to be contacted with. If such scenarios are available, then the agent selects the nearest one and makes a step towards it. If the scenario has been opened by one of the teachers, then this is already an author’s scenario and the teacher-agent takes an action to reuse it. Variants of the reuse can be preset so that to correspond to the actions allowable in the environment of MES repository for learning scenarios: review, addition to bookmarks, running the scenario, downloading, using in home assignments. All these actions of teachers regarding scenarios are logged, then the log records are transformed into bipartite graph. The experiments demonstrate that while the area of participant scenarios is expanded, not only the general number of links among participants increases but also large networks of participants are subdivided into smaller and densely interconnected groups. One of the control trends of participant activities is in the use of multiagent-based modeling as a tool of collective reflection of teachers cooperating on the basis of MES.

In the field of Information Communication Technology (ICT), the demand for highly skilled professionals is increasing. To keep up with the modernized technology trends and to update the skill set, the best way for an ICT specialist or an undergraduate student is to register in a MOOC platform and follow the appropriate courses. However, given the large variety of MOOC platforms and courses, they may get confused as to which are the most beneficial and time worthy choices. The authors provide research of the users’ requirements, existing MOOC recommender systems and their features and propose a clientserver recommender system which enables users to choose an existing MOOC platform, based on ICT jobs and skills. The paper proposes a modern approach that helps IT specialists to plan their future development path based on MOOC recommendations, specific to ICT jobs and relevant to their development needs.

Modern computational tasks are often required to not only guarantee predefined accuracy, but get the result fast. Optimizing calculations using floating point numbers, as opposed to integers, is a non-trivial task. For this reason, there is a need to explore new ways to improve such operations. This paper presents analysis and comparison of various floating point formats – float, posit and bfloat. One of the promising areas in which the problem of using such values can be considered to be the most acute is neural networks. That is why we pay special attention to algorithms of linear algebra and artificial intelligence to assess efficiency of new data types in this area. The research results showed that software implementations of posit16 and posit32 have high accuracy, but they are not particularly fast; on the other hand, bfloat16 is not much different from float32 in accuracy, but significantly surpasses it in performance for large amounts of data and complex machine learning algorithms. Thus, posit16 can be used in systems with less stringent performance requirements, as well as in conditions of limited computer memory; and also in cases when bfloat16 cannot provide required accuracy. As for bfloat16, it can speed up systems based on the IEEE 754 standard, but it cannot solve all the problems of conventional floating point arithmetic. Thus, although posits and bfloats are not a full fledged replacement for float, they provide (under certain conditions) advantages that can be useful for implementation of machine learning algorithms.

This article is concerned with the analysis of the emergence of possible security threats to the object of informatization. The main types of threats and approaches to their definition are presented and described. Recommendations are given for determining their application regarding the object of informatization.

This article studies the operation of an optical sensor with a cylindrical measured surface. Various options for positioning the sensor are considered. The study provides an estimation of the influence of the radius of the cylindrical reflective surface on the sensor transmission function.

Decision support systems (DSS) allow us to help the doctor in making diagnoses to the patient, also medical DSS help to assess the need for a particular examination of the patient. In this article methods of medical data classification are considered, these methods are the part of the medical DSS. The paper includes investigation of data classification methods as hierarchical cluster analysis, k-means analysis and discriminant analysis. The selected methods are implemented using the example of cardiological data. A hypothesis is put forward that it is possible to determine the presence or absence of tuberculosis in a person from cardiological data by using data classification methods. Such indicators as sensitivity and specificity evaluate the effectiveness of the methods. In addition, ROC and AUC are presented. Thus, the DSS will be able to determine a certain degree of probability to assume the presence of tuberculosis in a person. The doctor will decide on the need for additional examinations depending on the values obtained.

The paper considers a non-contact method of controlling external defects of metal surfaces. The differential method of processing information obtained by ultrasonic echomethod from different measuring channels is used. Mathematical modelling of offered method has demonstrated its practical application. The structure of intelligent measuring device was proposed, a schematic diagram was developed and a prototype of the sensor was assembled. Tests have proved possibility of determining of small defects of metal surfaces.

This paper extends a newly developed computational optimization approach to a specific class of Maximal Covering Location Problems (MCLPs) with a switched dynamic structure. Most of the results obtained for the conventional MCLP address the “static” case where an optimal decision is determined on a fixed time-period. In our contribution we consider a dynamic MCLP based optimal decision making and propose an effective computational method for the numerical treatment of the switched-type Dynamic Maximal Covering Location Problem (DMCLP). A generic geometrical structure of the constraints under consideration makes it possible to separate the originally given dynamic optimization problem and reduce it to a specific family of relative simple auxiliary problems. The generalized Separation Method (SM) for the DMCLP with a switched structure finally leads to a computational solution scheme. The resulting numerical algorithm also includes the classic Lagrange relaxation. We present a rigorous formal analysis of the DMCLP optimization methodology and also discuss computational aspects. The proposed SM based algorithm is finally applied to a practically oriented example, namely, to an optimal design of a (dynamic) mobile network configuration.

The article discusses the features of modern processor’s microarchitecture, the method of instruction’s and micro-operation’s accelerated execution. The research focuses on the organization of the decoding stage in the CPU core pipeline and Macro- and Micro-fusion algorithms. The Macro- and Micro-fusion mechanisms are defined. A computer simulator has been developed to explore these mechanisms. The developed software has a user-friendly interface, is easy to use, and combines training and research options. The computer simulator demonstrates the sequence of mechanism’s implementation; the resulting macro- or microoperations set after Macro- and Micro-fusion, and also reflects each algorithm features for different processor’s families. The software allows you to use either a pre-prepared file with Assembler (x86) code fragments as source data, or enter/change the source code fragments at your request. The main combinations of machine instructions that can be fused into a single macro-operation are considered, as well as instructions that can be decoded into fused microoperations. The simulator can be useful both for in Computer Science & Engineering students, especially for on-line education and for researchers and General-purpose CPU cores developers.