The efficiency of the processes of performing tasks of various types in Flow Shop systems is ensured by the formation of packages and optimization of their orders for performing operations with them on the devices of these systems. The process of package execution is affected by instrument failures and downtime associated with recovery. The impact of instrument failures and repairs can be reduced by pre-maintenance. During the maintenance time intervals, the devices are unavailable for the implementation of their assigned functions. By processing statistical data, the time intervals between the pre-maintenance of the devices can be determined (the periods of their availability are determined). For this reason, it is important to solve the problems of optimizing package compositions, their inclusion in the time intervals for the availability of devices, and schedules for their execution in these intervals. With small problem sizes, their solutions can be determined by using mathematical models of mixed integer linear programming.

The purpose of the work is to build a new mathematical model of mixed integer linear programming, the use of which allows us to determine the optimal solutions of the type under consideration. To achieve this goal, the methods of constructing mathematical programming models are used in the work. At the first stage, the formation of a nonlinear mathematical model of integer programming was implemented. At the second stage, in order to reduce the time required to obtain solutions, the model was linearized. To verify the model, an application was developed in the IBM ILOG CPLEX program. In the course of the research, results were obtained that showed the effectiveness of the model in solving the tasks of planning the execution of task packages in conveyor systems with limited availability of devices.

The scientific novelty of the results suggests that the model uses a method for transferring tasks between two devices directly at the end of their execution on the previous device. Their theoretical significance consists in obtaining new expressions that make it possible to determine the values of indicator variables when the function values exceed the specified boundaries. Based on these expressions, constraints are formed that require the inclusion of all tasks of different types in packages in the time intervals of instrument availability.

Relevance. Reducing the computational cost of image alignment procedures is an important field of research. The article considers the problem of processing urban infrastructure images obtained by UAV. The development of a high-speed method will make it possible to construct a digital map of an area by images from several UAVs in a limited time (ideally in real-time), which can be used to solve operational problems.

Purpose of the work. Reducing the computational cost of the alignment procedure by preliminary estimating the parameters based on a limited sample of interest points.

Methods used: analytical review of relevant scientific publications, experiment, algorithmization.

The method for Image Alignment of Urban Infrastructure Images by UAV Shooting to make a digital map was developed to solve a scientific problem; the previously developed technique was enhanced; it reduced the computational complexity of image processing; the basis of the enhancement was the assumption that the transformation parameters range is limited; the advantage of the enhanced methodology were noted in the research.

Results. An enhanced method of image alignment is proposed, which is characterized by shorter processing time than the original one. Experimental testing showed a reduction in time by half (from 50 s to 23 s), as well as a satisfactory result in combining 100 pairs of images.

The work scientific novelty is determined by the author's approach to narrowing the range of the scaling coefficient and rotation angle for fragments matched of the alignment images. The approach is proposed for the first time.

Theoretical significance. The assumption was confirmed that fragments of the image of urban infrastructure taken by UAV have a limited range of transformation of scaling and rotation.

Practical significance. The research results can be used to make a machine vision system for digital map constructions in real-time. It provides a solution to operational problems of objects detecting and tracking the movement.

The purpose of the study is to select and justify the flight and technical characteristics of an unmanned platform for integration with a portable relay station in order to create mobile communication networks.

The relevance of this task is due to the need for prompt restoration of communication during the elimination of the consequences of emergencies, when the stationary infrastructure is damaged.

The methodology of the work includes a comparative analysis of the market of electric UAVs by the criteria of load-lifting and flight time, as well as a detailed aerodynamic calculation of the hovering time, taking into account the mass and energy consumption of the payload.

Results. It has been established that light commercial platforms do not have the necessary load capacity for standard repeaters. It has been shown that heavy agricultural UAVs are capable of carrying repeaters weighing up to 10 kg. Based on the analysis of the obtained non-linear dependence of flight time on load weight, it has been concluded that the miniaturization of repeaters is critical.

The scientific novelty of the work lies in the development of an algorithmic approach to configuring a mobile relay complex and establishing a quantitative non-linear dependence of the hovering time on the payload mass for heavy agricultural UAVs.

The practical significance of the results is to substantiate the choice of a specific carrier platform and relay equipment for creating an operational complex suitable for rapid deployment by emergency services and other forces.

Relevance: TSN technology is a promising direction of the Ethernet standard actively developed by IEEE which allows Ethernet to be effectively used for reliable timely transmission of traffic of various types and varying degrees of delay criticality.

Purpose: development of a semi-Markov simulation model for studying the reliability of TSN devices which allows to flexibly estimate probabilistic reliability characteristics and their dynamical changes.

Methods: simulation modeling in Python programming language, methods of the theory of Markov and semi-Markov processes, methods of time series data processing.

Results: a semi-Markov model has been developed that allows considering complex implicit dependencies between past device states and current transition probabilities; a variant of the model's operation scenario has been developed that includes a set of various influencing factors, and it has also been shown that the proposed model provides a dynamic view of device reliability parameters changes that differs from the results obtained using traditional analytical approaches. In addition, the simulation results have been verified, the smoothing method has been chosen and its choice has been justified, and a very small deviation of the statistical results of the simulation model from the analytical ones has been shown.

Novelty: the novelty lies in the difference between classical methods and the proposed approach to estimating device reliability parameters based on statistical simulation, as well as in the creation of complex multifactorial scenarios of device behavior.

Practical significance: the results of the work show the possibility of using simulation modeling for forecasting reliability problems, dynamically accounting for complex processes of degradation and restoration of a device during operation and, thus, can be further used in estimating the reliability parameters of various telecommunications and other technical devices.

Relevance of the research topic is simultaneously driven by technical, industry, and regulatory factors. First, mission-critical operational radiocommunications are a fundamental element in ensuring the safety and controllability of railway infrastructure; at the same time, current GSM-R-based solutions are reaching their limits in capacity and functionality. Second, spectrum scarcity and fragmentation in the 1785–1805 MHz band, as well as the need for its coexistence with other radio networks, necessitate spectrally efficient planning methods and the reduction of mutual interference. Existing radio planning practices are generally poorly adapted to the specifics of railways, increasing the risks of coverage shortfalls, degradation of handover performance, and failure to meet latency regulations. The comprehensive methodology proposed in this study for LTE‑1800 TDD delivers measurable reductions in mutual interference, expands zones of reliable coverage, ensures compliance with <50 ms latency for critical services, and enables rational use of scarce spectrum. Accordingly, the topic has high practical relevance for the modernization of existing lines, the design of new sections, and the phased migration to FRMCS/5G.

The main objective of the study is to develop and substantiate a comprehensive methodology for designing digital systems of operational railway radiocommunications based on the LTE‑1800 TDD standard under limited spectrum resources and stringent requirements for reliability and latency.

Results: mutual interference reduced by up to 30 %, the radius of reliable coverage increased by up to 15 % through antenna system optimization, guaranteed compliance with <50 ms signal delay requirements for control systems; the effectiveness of adaptive bandwidth selection is demonstrated. Adaptive multi-stage LTE‑1800 TDD planning for operational railway communications delivers measurable improvements in interference immunity, coverage, and latency under spectrum constraints and can serve as a practical design standard.

Scientific novelty: an integrated methodology with adaptive branching and a set of application-specific correction factors for the railway environment is proposed, ensuring simultaneous fulfillment of latency, robustness, and spectral efficiency requirements amid spectrum scarcity.

Practical significance: the methodology has been implemented in real-world design practice, improving the reliability of critical services and the efficiency of spectrum use.

Relevance. Open laser atmospheric communication systems are affected by weather conditions. A large number of model theoretical and experimental studies have been devoted to the influence of rains on the effectiveness of open laser atmospheric communication. However, the issue of choosing the parameters of an open laser atmospheric optical communication system with a star-shaped structure, taking into account the need to minimize signal loss, has not yet been considered.

The aim of the study is to develop a method for optimizing the star-shaped structure of open laser atmospheric communication in order to minimize the total loss of the optical signal due to visibility limitations at many distances between the center and peripheral nodes.

The essence of the method consists in compiling and solving a variational optimization problem for estimating the total losses in all directions of the star-shaped structure of the data transmission system using a selected well-known model of attenuation of the optical signal due to the effect of rain (in this model, the visibility indicator at distances from the center to the peripheral node is explicitly included).

Experiments. The conducted approbation experimental studies have generally confirmed the reliability of the models used as the basis of the conducted research.

As a result of theoretical model studies, an expression was obtained for calculating the maximum achievable total optical signal losses in star-shaped open laser atmospheric communication networks. In addition, it was found that in the star-shaped structure of open laser atmospheric communication, the maximum total losses of the optical signal in the case of accepting the integral constraint on the newly introduced functional dependence between the distances from the peripheral node to the center and local visibility occur in the case when the distance from the transmitting center to the peripheral receiving nodes is proportional to the square root of local visibility.

Practical significance. Based on the results obtained, recommendations have been developed for determining the distance of the reception nodes from the center. It is planned to implement the results obtained in the projected open laser atmospheric communication network "Center-suburban hubs" on the Absheron Peninsula.

Relevance. Wireless data transmission technology based on the IEEE 802.11 standard currently occupies a key place in wireless access networks. Since its introduction in 1997, it has undergone 28 years of active technological evolution. WiMAX, which existed since 2001, has virtually disappeared due to the development of LTE, while Bluetooth, which appeared in 1999, continues to evolve. Both technologies had the potential to replace Wi-Fi. WiMAX was initially intended to fill the gap between slow cellular networks and Wi-Fi, offering a compromise between mobility and speed. Bluetooth found its niche in the M2M segment. Today, we are seeing the rollout of the IEEE 802.11be amendment to the market, and the first results from the IEEE working group on the upcoming IEEE 802.11bn update. Over the years, standard has seen significant improvements across all layers of the protocol stack, and there is reason to expect that the new amendment will be, in some sense, technologically revolutionary.

The aim of this work is to identify patterns in the technological evolution of the IEEE 802.11 standard over the past period of development.

Methods. Analysis of professional and scientific literature, standards texts, and industry practices.

Speaking about its objective, this paper presents an overview of the key improvements made to the standard over the years past and examines the main areas of its current development. The focus is on the cyclical nature of the technological evolution of the IEEE 802.11 standard.

Its novelty lies in identifying and describing the patterns of the standard's development and its practical application. Its theoretical significance lies in the analysis of protocol development trends within the technology's evolution. It also demonstrates that the adoption of new additions to the IEEE 802.11 standard is cyclical, combining revolutionary breakthroughs with evolutionary changes.

Practical significance: The obtained results can be used to analyze and forecast further evolutionary changes in the technology in light of the expected transition to the eighth generation of the standard.

Relevance. In recent years, virtualized integrated systems have widely become the base architectural solution for industrial automation systems. TSN technology is being used in their telecommunications networks, as it is the most suitable solution for mission-critical applications with stringent requirements for speed and guaranteed information delivery. The quality of TSN networks, in turn, depends on the accuracy of their time synchronization. Therefore, developing methods to improve the accuracy of time synchronization of packet-switched network devices is a pressing scientific and practical challenge.

Purpose of the work: to examine ways to improve the accuracy of time synchronization in networks of virtualized integrated systems using TSN technology, and the impact of network clock synchronization provided by synchronous Ethernet technology.

Methods used: the impact of network clock synchronization on the accuracy of timescale reference is assessed using the results of simulation modeling of time and clock synchronization processes in the AnyLogic environment.

Results: the paper presents a chain of interactions between information and telecommunication technologies, as well as supporting telecommunication subsystems, demonstrating in aggregate the operating principles of complex embedded computer systems and a method for determining their characteristics based on modeling. The results of simulation modeling are also presented, demonstrating that high accuracy of time scale binding and stability of its retention can be achieved through the joint implementation of frequency and time synchronization, which plays an important role in TSN application scenarios.

Practical significance: implementing frequency synchronization in a network supporting TSN technology enables high-precision time synchronization of network devices while using fewer synchronization messages to reduce the amount of service traffic. This allows that to save costs less stable clock generators may be used, as their frequency is consistently adjusted.

Introduction. one approach to finding vulnerabilities in programs is converting the executable machine code into human-oriented source code, which would be more suitable for an information security expert. The authors previously developed a corresponding method for «smart» enumeration of source code variants to identify a copy that compiles to a given machine code. A logical continuation of this research would be the implementation of a software prototype to test the method's performance and experimentally determine some characteristics.

Purpose: implementing the software prototype of smart exhaustive search of source code variants (according to the described method), as well as the experimental evaluation of its operability and the limits of its applicability.

Methods: software engineering, experimentation, approximation of values.

Results. the creation of a software prototype for selecting an instance of the source code according to the set machine code, obtained in previous author's studies. The prototype was used to obtain the source code of a mathematical expression from its machine code using part of the formal syntax of a programming language (defined in the form of a graph of syntactic rules). A series of experiments was conducted to evaluate the characteristics of the prototype by determining the following dependencies: the number of all source code variants on the syntactic heterogeneity of the syntax and the maximum depth of traversal of its graphical representation, as well as the search time for a specific source code from a set depth of traversal. These tests proved the basic functionality of the prototype and its hypothetical potential, which also justifies the possibility of opposite reverse engineering as compared to the traditional method - from source code, rather than machine code.

Practical significance: the current version of the prototype can be used practically to decompile small parts of machine code, without being dependent on a specific programming language and processor architecture (since only a compilation tool is required).

Discussion: the qualitive optimization of the "smart" exhaustive search through the use of artificial intelligence in terms of genetic algorithms can significantly improve the search.

Commutative encryption, previously proposed by A. Shamir and published about 30 years ago in a monograph by B. Schneier “Applied Cryptography”, has not found practical application due to the lack of known strong ciphers possessing the commutativity property. This paper confirms that such well-known ciphers as AES, GOST-2015, El-Gamal and Mc-Eliece ciphers, indeed, do not possess this property. However, the authors managed to construct a modification of the RSA cipher using a new version of the protocol, which allows the exchange of confidential information without any preliminary distribution of both public and secret encryption keys between legitimate users. This property is just the relevance of the current paper, because, as a rule, a keys distribution problem is a bottleneck of Cryptosystem creation for their application to real confidential digital telecommunication system. Although such properties are close to the properties of so-called public-key cryptosystems, unlike them, the proposed cryptosystem can use the same public keys for an unlimited number of users. Such keys can be made publicly available, for example, by storing them in the cloud. It is this property of the proposed Cryptosystem that reflects the novelty of the approach, since, as the authors know, no key system has yet been described that does not require preliminary key distribution.

This property can be useful for certain scenarios involving the exchange of confidential data, such as passwords and broadcast information. In the first case we have in mind that it is necessary to authenticate users by some server. If it has in data base user’s passwords stored, then users are authenticated only upon presentation of the corresponding passwords. However, communication channel used for such authentication is vulnerable to adversary’s interception, but our scheme prevents password’s disclosing. Another practical outcome of the proposed Cryptosystem consists in application to the broadband channels, if it is necessary to minimize the number of encryption keys used.