St. Petersburg State University of Telecommunications

About: St. Petersburg State University of Telecommunications is a education organization based out in Saint Petersburg, Russia. It is known for research contribution in the topics: Computer science & The Internet. The organization has 408 authors who have published 465 publications receiving 2160 citations.

Fractal lattice of gelatin nanoglobules

Abstract: The globular structure of polymer coatings on a glass, which were obtained from micellar solutions of gelatin in the isooctane-water-sodium (bis-2-ethylhexyl) sulfosuccinate system, has been studied using electron microscopy. It has been shown that an increase in the average globule size is accompanied by the formation of a fractal lattice of nanoglobules and a periodic physical network of macromolecules in the coating. The stability of such system of the “liquid-in-a-solid” type is limited by the destruction of globules and the formation of a homogeneous network structure of the coating.

Electron multichannel scattering by narrows of quantum waveguides

Abstract: Recent years show sharp increase of interest in the study of devices based on electron transport in nanowires. Such devices can be used as field effect transistors [1], resonant tunneling diodes [2], lasers [3], as well as qubits [4]. Quantum resonators in nanowires (quantum waveguides) can be created by application of an external potential to certain areas of the waveguide [2]. However, there is a much easier way to create quantum resonators: by forming two or more narrows in the waveguide [5, 6]. To analyze the effect of the narrows in the quantum waveguide on electron transport let us first briefly consider the distribution of electron wave of arbitrary energy in an undeformed waveguide.

Radiation-induced loss of silica optical fibres with fluorine-doped cladding

Abstract: The effect of gamma-irradiation of the fluorine-doped silica depressed cladding graded-index fibre (DCGIF) has been researched. New mechanism of the non-bridging oxygen hole centers (NBOHC) defect formation, conditioned by different mobility of diffusion counter flows of fluorine and oxygen at the core-cladding interface, has been proposed. Using silica tubes with 0.02 wt% of OH groups and hydrogen in free state in MCVD-technology of DCGIF fabrication completely eliminates the NBOHC absorption at the wavelength of 630 nm. However, gamma-irradiation of such fibres results in anomalously high attenuation level in the visible range of optical spectrum. It was established that irradiation of DCGIF leads to light scattering which is probably due to the appearance of optical inhomogeneities in the glass matrix.

Implementation Methods for SDN Controllers in a UAV Network

Abstract: Research subject. The division of the performed functions between all UAVs of the same cluster, a comparison of the methods for implementing the SDN controller into the UAV network, a description of the sequence of actions implemented in the UAV cluster, depending on a specific application scenario. Method. Analysis of standards and recommendations in the field of SDN technologies and construction of UAV networks; Comparison of SDN controller implementation methods: outside the cluster, on the head node, on all UAVs of the same cluster, and implementation using two controllers (one outside the cluster, and the second on the head node). Core results. 4 ways of using the UAV are described in de-tail, as well as the sequence of actions performed by the UAV cluster for each method; Compared 4 ways to implement the SDN controller in the UAV network; A method for dividing the performed func-tions between UAVs of one cluster is presented. Practical relevance. The sequences of actions pre-sented for each method of application will allow in the future to implement the execution of these scenar-ios using a UAV cluster; The article details the advantages and disadvantages of all four ways to imple-ment an SDN controller; the presented method of dividing functions between UAVs has less resource consumption for individual UAVs and for the entire cluster as a whole, than with the method with the im-plementation of all functions on each UAV of the cluster.

Fiber-Optical Communication Line with a System for Compensation of Radiation-Induced Losses During the Transmission of Information

Abstract: This research is focused on γ-radiation, the main negative factor which causes significant losses in fiber-optical communication lines. We determine the methods for increasing the relaxation rate of color centers that are formed in an optical fiber under the influence of γ - radiation. Moreover, we develop the design of the fiber-optic communication line with the compensation of radiation-induced losses at the moment of exposure to the optical fiber γ - radiation. The results of experimental investigations are presented.