Protection of information networks based on LoRa technology

The paper deals with modern technology for transmitting short messages over long distances named LoRa, where the transmitted signal uses linear frequency modulation (chirp). The object of the study to define lack of transmitters that it has a design on LoRa technology for assessment their applicable in condition urban city where there are a lot of radiation sources. The goal of the work is the creation of a method of assessing the act the interference conditions that based on measurement bit error rate and signal-noise ratio and via on which to get individual host vulnerability levels. The processing of these signals is carried out by means of a time-frequency transformation. The chirp signal is characterized by 4 parameters: frequencies, time, modulation rate and amplitude. By analogy with the wavelet transform, the processing of chirp signals involves a chirplet decomposition. Since the chirp signals are strongly influenced by mutual interference due to multipath, the article studies the effectiveness of LoRa technology in conditions of mutual interference of radiation sources. The developed method utilized chirplet decomposition and retrieve symbols of a message in the dictionary. The conducted experiments have confirmed the proposed software operability and allow recommending it for use in practice for solving the problems receiving signal. The prospects for further research may include the creation of parallel methods for calculation of the set of proposed indicators, the improvement of software, as well as an experimental study of proposed indicators in real conditions.The paper deals with modern technology for transmitting short messages over long distances named LoRa, where the transmitted signal uses linear frequency modulation (chirp). The object of the study to define lack of transmitters that it has a design on LoRa technology for assessment their applicable in condition urban city where there are a lot of radiation sources. The goal of the work is the creation of a method of assessing the act the interference conditions that based on measurement bit error rate and signal-noise ratio and via on which to get individual host vulnerability levels. The processing of these signals is carried out by means of a time-frequency transformation. The chirp signal is characterized by 4 parameters: frequencies, time, modulation rate and amplitude. By analogy with the wavelet transform, the processing of chirp signals involves a chirplet decomposition. Since the chirp signals are strongly influenced by mutual interference due to multipath, the article studies the effectiveness of LoRa technology in conditions of mutual interference of radiation sources. The developed method utilized chirplet decomposition and retrieve symbols of a message in the dictionary. The conducted experiments have confirmed the proposed software operability and allow recommending it for use in practice for solving the problems receiving signal. The prospects for further research may include the creation of parallel methods for calculation of the set of proposed indicators, the improvement of software, as well as an experimental study of proposed indicators in real conditions.National Aviation Universit

Protection of information networks based on LoRa technology

The paper deals with modern technology for transmitting short messages over long distances named LoRa, where the transmitted signal uses linear frequency modulation (chirp). The object of the study to define lack of transmitters that it has a design on LoRa technology for assessment their applicable in condition urban city where there are a lot of radiation sources. The goal of the work is the creation of a method of assessing the act the interference conditions that based on measurement bit error rate and signal-noise ratio and via on which to get individual host vulnerability levels. The processing of these signals is carried out by means of a time-frequency transformation. The chirp signal is characterized by 4 parameters: frequencies, time, modulation rate and amplitude. By analogy with the wavelet transform, the processing of chirp signals involves a chirplet decomposition. Since the chirp signals are strongly influenced by mutual interference due to multipath, the article studies the effectiveness of LoRa technology in conditions of mutual interference of radiation sources. The developed method utilized chirplet decomposition and retrieve symbols of a message in the dictionary. The conducted experiments have confirmed the proposed software operability and allow recommending it for use in practice for solving the problems receiving signal. The prospects for further research may include the creation of parallel methods for calculation of the set of proposed indicators, the improvement of software, as well as an experimental study of proposed indicators in real conditions.The paper deals with modern technology for transmitting short messages over long distances named LoRa, where the transmitted signal uses linear frequency modulation (chirp). The object of the study to define lack of transmitters that it has a design on LoRa technology for assessment their applicable in condition urban city where there are a lot of radiation sources. The goal of the work is the creation of a method of assessing the act the interference conditions that based on measurement bit error rate and signal-noise ratio and via on which to get individual host vulnerability levels. The processing of these signals is carried out by means of a time-frequency transformation. The chirp signal is characterized by 4 parameters: frequencies, time, modulation rate and amplitude. By analogy with the wavelet transform, the processing of chirp signals involves a chirplet decomposition. Since the chirp signals are strongly influenced by mutual interference due to multipath, the article studies the effectiveness of LoRa technology in conditions of mutual interference of radiation sources. The developed method utilized chirplet decomposition and retrieve symbols of a message in the dictionary. The conducted experiments have confirmed the proposed software operability and allow recommending it for use in practice for solving the problems receiving signal. The prospects for further research may include the creation of parallel methods for calculation of the set of proposed indicators, the improvement of software, as well as an experimental study of proposed indicators in real conditions.National Aviation Universit

Bayesian wavelet de-noising with the caravan prior

According to both domain expert knowledge and empirical evidence, wavelet coefficients of real signals tend to exhibit clustering patterns, in that they contain connected regions of coefficients of similar magnitude (large or small). A wavelet de-noising approach that takes into account such a feature of the signal may in practice outperform other, more vanilla methods, both in terms of the estimation error and visual appearance of the estimates. Motivated by this observation, we present a Bayesian approach to wavelet de-noising, where dependencies between neighbouring wavelet coefficients are a priori modelled via a Markov chain-based prior, that we term the caravan prior. Posterior computations in our method are performed via the Gibbs sampler. Using representative synthetic and real data examples, we conduct a detailed comparison of our approach with a benchmark empirical Bayes de-noising method (due to Johnstone and Silverman). We show that the caravan prior fares well and is therefore a useful addition to the wavelet de-noising toolbox.Comment: 32 pages, 15 figures, 4 table

A Fusion Framework for Camouflaged Moving Foreground Detection in the Wavelet Domain

Detecting camouflaged moving foreground objects has been known to be difficult due to the similarity between the foreground objects and the background. Conventional methods cannot distinguish the foreground from background due to the small differences between them and thus suffer from under-detection of the camouflaged foreground objects. In this paper, we present a fusion framework to address this problem in the wavelet domain. We first show that the small differences in the image domain can be highlighted in certain wavelet bands. Then the likelihood of each wavelet coefficient being foreground is estimated by formulating foreground and background models for each wavelet band. The proposed framework effectively aggregates the likelihoods from different wavelet bands based on the characteristics of the wavelet transform. Experimental results demonstrated that the proposed method significantly outperformed existing methods in detecting camouflaged foreground objects. Specifically, the average F-measure for the proposed algorithm was 0.87, compared to 0.71 to 0.8 for the other state-of-the-art methods.Comment: 13 pages, accepted by IEEE TI