The ultra-long LPDC codes are examined. The errors correction by ultra-long LDPC codes is analyzed. The error-correcting capability research method for ultra-long LDPC codes is described in details. The main results in table and graph representations are shown. The comparison of ultra-long LDPC codes and BCH codes is performed by using Plotkin and Varshamov-Gilbert limits approximation criterion.

Освещен вопрос, касающийся решения проблемы обнаружения слабых аналоговых сигналов на фоне сильного шума с обеспечением гораздо большего выигрыша в отношении сигнал/шум в сравнении с уже существующими техническими решениями. Рассмотрено устройство обработки сигналов, описана сущность способа, условия достижения поставленной задачи получения максимального выигрыша в отношении сигнал/шум, превышающего 50 дБ, и преимущества рассмотренного устройства, которое является эффективным для систем обработки информации с малым уровнем мощности.

It is common to think that impulse radio ultra band signals (IR-UWB) in communication systems can carry the information at very high rates. But each impulse of the signal can carry just one bit of information. In radio networks it is necessary to add destination address to every information unit. The best way for each subscriber is use series of impulses mutually orthogonal to the rest of series in the network. But the orthogonality means long multi impulse series with low density of impulses to make time domain space transparent. As a result, data transmission rates become much less than expected. To increase data rates in radio networks modulation of each impulse by amplitude, duration and polarity in the series is proposed. Examples of transmitter and receiver are presented. As a result, informative loading on signals increases manifold, compensating or neutralizing losses, related to the transmission of symbols by impulse sequences.

In the paper a multilevel intellectual approach to HTTP-requests legitimacy validation is proposed. The approach is devised for HTTP-flood DDoS-attacks detection and prevention in telecommunication networks with a web-server as the target attack object. The analysis of HTTP-requests attributes and their signatures is provided. On the basis of the analysis the attributes are separated into several levels that allow us to design a flow analyzer in a form of the multilevel block. Due to a multilevel structure of the flow analyzer a minimization of resources, spent for a request handling, is achieved.

The article is devoted to ontology for the knowledge portal on radio engineering and telecommunication history development. We emphasize the ontology for basic portal which consists of eleven classes: "researchers", "researching techniques", "sources", "events", "organizations", "geographical location", "memorial object", "period", "scientific result", "branch of science" and "subject under investigation". The last three classes are represented as metanotions of portal subject ontology which include 19 first level subclasses and 60 second level subclasses. Inheritance and implication, as well as "class - data" dependences have been determined on the base of classes and subclasses. Thirty most actual associative dependences have been emphasized. The division of large sources (monographs and reviews) into smaller fragments and organization of subclass "quotations" in order to simplify the process of ontology development and to realize the most relevant search are proposed. Set theory tools and "two - level" concept of science and technology historiography as a metascience have been used in the process of formalization.

This paper addresses to a method for increasing of mobile ad-hoc networks throughput based on the placement control of unmanned aerial vehicles in the area of emergency situation. A further development of this method, namely the improvement of UAV flight control subsystem, that will allow operative implementation of obtained in the previous stage location coordinates while minimizing energy consumption for control, is proposed. The proposed approach will improve network throughput by 15 - 20 % while reducing fuel costs by an average of 13 - 15 %.

Індекс рубрикатора НБУВ: З845.7-040.2

Рубрики:

Хвилевідні лінії передачі. Хвилеводи та об'ємні резонатори

Шифр НБУВ: Ж100651 Пошук видання у каталогах НБУВ 

The class of resonators which allows building mechanically tunable waveguide bandpass filters with near constant bandwidth in overall a wide tuning frequency range has been investigated. The concept comprising in a successful combining inductive and capacitive discontinuities to obtain near constant quality factor of resonators in wide frequency variation range is implemented. It is proved that the most technologically advanced solution can be obtained by using the waveguide connections containing double ridged sections for compensation of phase shifts in resonators appearing because of frequency variation. Adequate mathematical models of the resonators based on generalized scattering matrix approach are obtained. The diffraction problems for doubled discontinuities, such as doubled ridged sections in rectangular waveguide, have been solved by the integral equation method. The calculation of resonance frequencies and quality factors of resonators are carried out in wide dimension range variations. Due to near constant quality factors over wide tuning frequency range, the developed waveguide resonators open new possibilities in realization of high efficient and cost effective frequency tunable filters of transmit tropospheric stations and various telecommunication systems for tropospheric communication.

This paper proposes and investigates a service model of the voice traffic in multiprotocol label switching networks. The study of Multiprotocol label switching networks (MPLS) requires a formal description of processes occurring in them, development of mathematical models, reflecting main properties of the investigated object and allows calculating the values in the required operating mode. In this paper, we develop the model of functioning MPLS network in the form of a multi-phase, multi-channel, open-loop system. We propose analytical expressions describing the process of mutual influence when servicing requests of various communication directions. To determine parameters of quality of service quality and bandwidth channels MPLS network, necessary compare them with the values of normed and assess the compliance of the specified standards.