Електронний архів наукових та освітніх матеріалів КПІ ім. Ігоря Сікорського
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- Стара назва до 1.09.2025 року - Інженерно-хімічний факультет (ІХФ)
- Припинив існування 1.07.2018
- Припинив існування 1.07.2020
Нові надходження
VoIP system with high availability
(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2025) Pryimak, Serhii O.; Kravchuk, Serhii O.
Background. With the exponential growth of the internet and an increasing number of VoIP (Voice over IP) deployments arose a need to manage and scale the systems in terms of high availability and minimal downtime. Objective. The purpose of the paper is to reveal methods of increasing the VoIP system’s availability. Main challenges associated with the operation of VoIP systems are analysed, particularly the need to ensure service continuity, fault tolerance, scalability and resource efficiency. Methods. Increasing the availability of a VoIP system is based on the use of free software: Kamailio (SIP signalling server), RTPengine (media traffic processing), Redis (in-memory database for storing RTP transactions), and Linux Ubuntu as a host operating system. Results. The implemented architecture reflects automatic failover of signalling servers and media gateways, load balancing and seamless switching to a backup node in case of failure of one or more components. Conclusions. The approach given drastically differs from others, where failure of one of the key elements (the signalling server or the media gateway) leads to immediate termination of all active connections. An experimental simulation of the system was performed by deploying a high availability schema depicted in Fig. 2 in a virtual environment and confirmed its high efficiency: even in the event of 50% of component failure, the system remains operational and does not interrupt any call.
Possibilities of increasing the energy of radio lines for controlling drones
(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2025) Berdnykov, Oleh M.; Hichko, Yurii G.; Mazor, Serhii Yu.; Khranovska, Tetyana V.
Background.The creation of an antenna system consisting of two spiral structures for the 2,4 GHz and 5,8 GHz frequency bands is caused by practical needs determined by the results of using drones to monitor the environment. The proposed technical solution was based on a study of known antennas for the 2,4 GHz (right circular polarisation) and 5,8 GHz (left circular polarisation) frequency bands. Due to the mismatch of the polarisation of the electromagnetic wave and the antenna, losses of up to 20 dBp can occur. To reduce losses, a design of spiral antennas with the ability to change the polarisation direction was proposed. The article discusses the physical nature of the work and the relationship between the design and electrical parameters of spiral antennas. These provisions provide directions for improving these characteristics and technical solutions for their realisation. When creating the proposed design, the core issue was to solve the problem of matching the direction of polarisation of the electromagnetic wave generated by the antenna of the ground control station with the direction of the drone antenna rotation. The problem is proposed to be solved by ensuring the possibility of promptly changing the polarisation of the ground control station antenna. The prototype for the development of such an antenna is a well-known antenna without the possibility of changing the polarisation, which has two coaxial spirals for the frequency bands 2,4 GHz and 5,8 GHz with different types of polarisation. Objective. The article aims to develop a dual-band antenna system for a ground control station with the ability to change the direction of rotational polarisation. Methods.A certain number of sources concerning rotationally polarised antennas, various types of ultra-high frequency antennas, and their application for communication between a ground control station and a drone have been reviewed and analysed. According to the problem statement, spiral antennas were selected for the antenna array elements, which provide the possibility of communication with a drone when changing the direction of rotational polarisation. Various antenna designs can solve the creation of a rotationally polarised wave. One solution is to use horn antennas and vibrator-type antennas, however from the perspective of the ratio of antenna gain and its dimensions, it makes sense to choose a spiral antenna. Results.The results of modelling the structural, technical, and electrical characteristics of the antenna system indicate the possibility of creating a dual-band spiral antenna design for use on ground control stations for radio contacts with UAVs in the frequency bands 2,35 ... 2,45 GHz and 5,75 ... 5,85 GHz. Conclusions.The implementation of the antenna system of spiral antennas for ground control stations in the frequency bands 2,35 ... 2,45 GHz and 5,75 ... 5,85 GHz for drone control makes it possible to change the direction of rotational polarisation, which is related to the drone antenna’s rotational polarisation direction
Method for redistributing electricity in a Microgrid network based on an ontological model
(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2025) Stepanov, Glib O.; Novogrudskaya, Rina L.
Background. Effective management of electricity distribution in microgrid networks is a key factor in ensuring such systems' reliability, stability, and flexibility. Due to the decentralisation of energy systems and the active introduction of renewable energy sources, there is a growing need for adaptive methods of electricity redistribution that can consider dynamic changes in load and generation. Existing approaches are mostly based on rigid algorithms or centralised control, which makes it difficult to implement flexible scenarios and leads to limited adaptability. The absence of a unified knowledge representation complicates the interaction between Microgrid elements and creates obstacles to system expansion. Objective. The purpose of this paper is to develop a method for redistributing electricity in a Microgrid using an ontological model that will provide a consistent representation of knowledge about system elements, their interconnections, constraints, and priorities. The proposed approach should facilitate context-oriented decision-making and increase the level of the power system autonomy without the need for radical changes in control schemes. Methods. The paper analyses typical scenarios of electricity redistribution, identifies conflicts of interaction between Microgrid nodes, and proposes an ontological model that reflects the system structure, connections between sources and consumers, load priorities, and decision-making rules. The main attention is paid to the construction of a formalised knowledge base that ensures interoperability and flexibility in management. Results. The analysis has confirmed that most existing electricity management systems have limited capabilities to adapt to dynamic changes and do not take into account the semantic relationships between system elements. The proposed ontological model allows for realisation of dynamic energy redistribution, taking into account the context and a set of factors. This ensures an increase in the reliability of the Microgrid and also contributes to a faster response to changing operating conditions. Conclusions. The proposed method of redistributing electricity in a Microgrid based on an ontological model is a promising direction for building adaptive and intelligent energy systems. Further research is planned to be directed to the implementation of a prototype of the software control module, as well as to the expansion of the ontology to take into account the specifics of various Microgrid configurations.
І науково-практична конференція магістрантів ФМФ (за результатами дисертаційних досліджень магістрантів) 27 листопада 2025 р.
(КПІ ім. Ігоря Сікорського, 2025)
У збірнику представлено статті молодих фахівців з актуальних проблем фізики, математики та методики викладання природничих дисциплін на І науково-практичній конференції магістрантів ФМФ. До збірника включено статті за такими напрямками: моделювання фізичних процесів, магнетизм конденсованого стану, спінтроника, наноматеріали, тепловізійні технології, нові матеріали, фінансова математика та методика викладання природничих дисциплін.
Друкується за рішенням організаційного комітету науково-практичної конференції «І науково-практична конференція магістрантів ФМФ (за результатами дисертаційних досліджень магістрантів)».
Optimal timing strategies in blockchain block proposals by one-bullet silent duels with one-third progression
(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2025) Romanuke, Vadim V.
Background. Silent duels and related timing games offer a surprisingly deep lens into certain core challenges in blockchain technology, especially when it comes to block proposal timing. Miners or validators effectively “compete” in a race to propose the next block. The success of a block proposal depends not only on when it happens but also on whether others have already succeeded or interfered — very much like the tension in a one-shot duel with uncertain outcomes. In block proposal timing for decentralized consensus protocols, a one-shot timing game models a blockchain setting, where participants (e. g., validators or miners) choose when to attempt block proposal or transaction insertion under uncertainty.
Objective. The paper aims to determine the best timing strategies for the participants. Considering two identical participants, the local objective is to find pure strategy solutions of a timing game (duel) with shooting uniform jitter.
Methods. A finite zero-sum game is considered, which models competitive interaction between two subjects to make the best discrete-time decision by limited observability. The moments to make a decision (to take an action, to shoot a bullet) are scheduled beforehand, and each of the subjects, alternatively referred to as the duelists, has a single bullet to shoot. Shooting is only possible during a standardized time span, where the bullet can be shot at only specified time moments. In the base pattern, apart from the duel beginning and final time moments, every following time moment is obtained by adding the third of the remaining span to the current moment. However, the precise time moment specification is not always realizable (e. g., due to the distance between neighbouring time moments being measured with finite accuracy) and so the internal moments are uniformly jittered. This means that they can be slightly shifted within the duel span. The duelist benefits from shooting as late as possible, but only when the duelist shoots first. Both the duelists act within the same conditions by linear shooting accuracy, and so the one-bullet silent duel is symmetric, regardless of the jitter. Therefore, its optimal value is 0 and the duelists have the same optimal strategies, although they still can be non-symmetric.
Results. By the one-third progression pattern with jitter, the 3 x 3 duel always has a pure strategy solution. The 4 x 4 duel is pure strategy solvable by any possible jitter except for jitter interval mceclip1.png. Within this interval and interval (-11/54; -1/18) the 5 x 5 duel is pure strategy non-solvable. The 6 x 6 duel is pure strategy solvable by any possible jitter except for jitter intervals mceclip2.png and (-49/162; -1/18). Duels with seven to nine time moments are pure strategy solvable only by a jitter interval of mceclip3.png. Bigger N x N duels, having no fewer than 10 time moments, are pure strategy solvable only by a jitter interval of [-1/18; 2N-2/3N-2). The solutions for the one-third progression pattern are compared to the known solutions for the geometrical-progression pattern.
Conclusions. The duel pure strategy solutions obtained suggest a clear one-step-action strategic behaviour in progressive block proposal timing for decentralized consensus protocols under uncertainty of time slots to act. The main benefit is full fairness and a potential reward if the opponent acts non-optimally, even in a single proposal.