This paper considers the scenario when the resulting logical channel for a secondary user in a cognitive radio system is formed by the algorithm minimizing the number of physical channel changes. The stochastic activity of primary users in a physical channel is characterized by a simple Markov chain. We present the analytical method for forming an accurate stochastic model (a simple Markov chain) of the resulting logical channel. The method is based on the aggregations of the graph states describing the channel change process in the algorithm. The result of the method describes the stochastic availability of the resources for a secondary user in the formed logical channel.

One of the significant drawbacks of OFDM and N-OFDM systems is high peak-to-average power ratio (PAPR). The use of N-OFDM signals gives an opportunity to reduce PAPR practically with the same methods that are applied to traditional OFDM. In this way, N-OFDM gives a considerable gain in spectral efficiency with a comparison to OFDM. In the article, the results of PAPR reduction of N-OFDM signals are presented. The implementation of phase response according to the analytical expression for the initial phase calculation of each subcarrier allows PAPR minimization an average of 12 dB for 155 subcarriers.

The study is devoted to the problem of informatization development in rural regions. The basis of development is the organization of information structure on the basis of telecommunication services. Substantiations of the development of services in accordance with the income of the population are carried out. The existing methodologies for estimating telecommunication development are correlated with averaged values without the population income distribution, without separating business needs of services in rural areas and the city. Comparison of information base development levels is made according to the criterion «the share of services in the average per capita population income». The expediency of informatization development in rural areas for specific economic conditions considering the average per capita income of rural residents is defined. Directions of the application field of financial efforts for the development of the information base of rural areas in the constituent entities of the Russian Federation. The materials of the study allow to determine appropriateness and level of investment in the regions.

A fuzzy model of competitive index for e-commerce is proposed. The model considers 12 factors via 94 fuzzy rules. The model was tested on 12 e-companies and showed high level of efficiency.

The research results of optical cable sections in the pre-emergency state due to the increased strain or its optical fiber temperature change both by means of traditional optical pulse reflectometers and with the help of the Brillouin optical reflectometer are presented in this paper. The results of the tests confirmed the advantage of the Brillouin reflectometry method for early diagnostics and detection of “problem” sections of fiber-optical communication lines.

The problem of finding integral Cayley graphs for alternating groups A_n, where n = 4,5,6,7,8, with different generating sets is considered and also the hypothesis of the integrality of Cayley graphs of finite group generated with an invariant set of involutions is tested. The hypothesis is tested for Dihedral groups D2_n with n = 6,7,...,132, linear groups L2(n) with n = 5,7,8,9,11,13, and symmetric groups S_n with n = 3,4,5,6. The diameters of Cayley graphs for these groups are presented.

In this paper, AlGaN/GaN lateral Schottky barrier diodes (SBD) with anodes based on Ta, Ni, WSi and Ta are considered. Heterostructure AlGaN/i-GaN/buffer GaN was grown by Metal Organic Chemical Vapor Deposition (MOCVD) on silicon (111) substrate. All diodes had 5 nm (50%) anodes recess. Anode-cathode distance was varied from 3 to 7 цт. Diodes periphery (anodes width, W) was 10 mm. Diodes turn-ON voltage (by forward current 1 mA/mm) critically depends on anodes material and was 0.25 V, 0.45 V, 0.65 V and 1.6 V for Ta, Ni, WSi and TiN anodes respectively. Specific leakage current also depends on anodes material and was 67 цЛ/тт, 13 цЛ/тт, 5 цЛ/тт and 0.85 цЛ/тт for Ta, Ni, WSi and TiN respectively.

With the technical implementation of hydroacoustic phase direction finders with ultrashort base, the problem of determining the hydrophones acoustic centers location of the receiving antennas is very actual. A method for phase-difference measurements of the acoustic centers displacement of spherical hydrophones is proposed allowing to improve significantly the accuracy of their calibration.

The development and implementation of multi-band conformal antenna systems (CAS) into small and medium range UAVs have been considered. The dual-band (Ku, UHF) multifunctional airborne radar complex (MARC) is used as an example. The considered CASs do not degrade the aerodynamic characteristics of the UAVs. They allow to expand significantly MARC functional capabilities and to solve defensive and national economic tasks. A methodology for creating MARC conformal antenna systems for such UAVs has been developed. The use of conformal antennas with substrates from metamaterials is one of the ways of implementing these CASs.

The article is devoted to foreign experience analysis of quality management systems models. Comparative characteristics of the most popular models are carried out. The idea of the relationship between the quality management system implemented in the company and its production system is given. For each of the models, conclusions concerning their main advantages and disadvantages are presented. Parallels with Russian companies are made. The article is of practical interest for companies implementing quality management systems especially in services sector.