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In today’s world of globalization and the development of information technology, it is not possible to build a business and production without using the latest advances in science and technology related to information technology. The most promising branches of the direction of information technology are the development and application of cryptographic means of protecting information for various purposes, including the use by government bodies and commercial organizations, the implementation of electronic document management tools, the expansion of the use of encryption schemes based on public keys and means of protecting web resources from DoS attacks. It is necessary to give the following assessment that the problem of countering and repelling Denial of Service attacks is an urgent problem in connection with the widespread introduction of information technologies and the globalization of the Internet, which, in turn, requires effective protection methods corresponding to the adequate cost of providing services. This paper proposes a practical implementation of a technique for detecting one of the most common DDoS attacks at the L7 level of the OSI model - HTTP Flood.

Degradation of land used in agricultural production is studied. Different land use practices influence on the organic carbon content in arable soils of agrolandscapes on arid territories as an example. By the example of Rostov and Samara regions, the existing agricultural land ownership structure has been analyzed, and the dynamics of sown areas and humus content in arable soils has been studied. It is shown that in the course of the land reform there was a redistribution of land ownership, which is more pronounced in the Samara and Rostov regions than in the Russian Federation as a whole due to agricultural land predominance in the land fund. Agricultural landscapes in the provinces occupy most of the studied regions and are currently characterized by the processes of degradation. Private land ownership does not guarantee the implementation of measures to preserve and improve soil fertility without the development in the implementation of regulatory and legal framework for the rational use of land at the regional or federal level. Without the development of a system of comprehensive measures to organize the rational use of land at the federal and regional levels, landscape agro-ecological condition will continue to deteriorate.

The purpose of the study: to identify the effect of the dose of redispersible polymer powders and the type of low-modulus inclusions on the frost resistance of dry adhesives mixes made using Portland cement with the concrete base. Methods of research: The research was carried out on the basis of 75 freezing-thawing cycles. The following parameters were determined: compressive and flexural strength on samples 40x40x160 mm in accordance with GOST 30744; bond strength to the concrete base after 28 days hardening and after 75 cycles of freezing and thawing in accordance with GOST 31356. The dynamic modulus of elasticity was determined by the value of the ultrasonic pulse velocity on samples of 40x40x160 mm. The influence of prescription factors on the ratio of these values after 75 freeze-thaw cycles relative to the values after 28 days hardening under normal conditions was studied. Main results: The coefficients of frost resistance of the contact zone of the adhesive mortar made using dry mixes after 75 cycles of freezing and thawing exceeds the values of the coefficients of frost resistance according to the criteria of strength or dynamic elastic modulus. Dry adhesives mixes of class C1 with a dosage of redispersible polymer powder from 1 to 3% and an air-entraining admixture after 75 freezing cycles may be corresponded to class C2. The coefficient of variation in the compressive strength of mortar inside a series of samples after 28 days of hardening under normal conditions is not appropriate to consider as an indicator of the homogeneity of the mortar structure, potentially having a high resistance to cyclic freezing-thawing.

Tunnel lining takes significant loads from moving vehicles. The consequences of their impact depend on the design of the railway track and the deformation characteristics of its elements. For their study, a numerical model of a circular tunnel has been developed. As a result of the model calculation, the values of the main vertical stresses in the main tunnel structures were obtained. It is established that with increasing loads from the wheel to the rail from 100 to 200 kN, the voltage on average increases by 50%. The stress distribution is affected by the rigidity of the elastic layer. When it increases, the vertical stresses in the sub-rail support decrease nonlinearly, while in traveling concrete they increase nonlinearly.

In the paper was indicated the essentiality of large-scale underground space development and high-rise construction of cities in Russia. The basic elements of transport facilities construction effective technology without traffic restriction are developed. Unlike the well-known solutions, it offers the inclusion of an advanced lining in the construction that strengthens the soil mass. The fundamental principles of methods for determining stress in advanced support and monitoring of underground construction, providing the application of pressure sensors, strain sensors and displacement sensors are considered.

Background. Ensuring the surface quality of critical products of aviation equipment, chemical, power engineering, transport systems for various purposes presents certain requirements for the equipment on which surface formation is carried out. Most parts, including those made of hard-to-work materials, are turned on CNC machines, which requires you to select cutting modes that provide specified values for accuracy and quality parameters. Machining modes are determined by the interaction of a specific tool-part pair and the dynamic quality of the machine. Machining on lathe machines using automation tools is a complex process that depends on the properties of the dynamic machine system. The forming process on the lathe is accompanied by vibroacoustic vibrations, the spectrum of which is quite wide and is determined by the interaction of the tool and the part, depending on the cutting force, the physical and mechanical properties of the materials of the contacting bodies, the chip formation process, friction in the cutter-part contact and other factors. The overall influence of these factors brings the oscillation spectrum of the cutting force acting on the DS closer to the oscillation spectrum of the “white noise” type. By changing the cutting modes, you can determine the values corresponding to the highest dynamic quality of the machine and the quality of processing from the characteristics of VA oscillations of the ET. Materials and methods. The Gagarin Yu.A. State Technical University has developed a method for assessing the dynamic quality of machines in various cutting modes based on the stability margin of the ET, calculated from its transfer function, identified by the autocorrelation function of VA oscillations. Cutting mode is assigned to maximum stability margin of ET at preservation of preset values of macro- and microgeometric parameters of processing quality. The method has shown high efficiency in turning hard-to-process materials, taking into account the specifics of processing. Results and conclusions. During cutting of hard-to-process materials, values of processing parameters are changed, values of coefficients a0,..., a5 in transfer function are corrected and, accordingly, stability margin of ET is changed. The above is confirmed by the experimental results of research on the cutting process on a CNC lathe. Thus, the stability margin of the ET can serve as an assessment of the dynamic quality of the machine in various cutting modes when processing different groups of hard-to-process materials.

Assessment of engineering status of railway tunnels with a long working lifespan causes the necessity of definition of the actual stress-strain state of construction design, taking into account the results of inspection of its engineering status. static analysis of lining in this case is performed by finite elements method. In the article the example of such analysis is given. The tunnel is strengthened by the composite tunnel lining consisting of an inner layer of masonry body and a shotcrete outer layer built while rebuilding operation. In response to the inspection considerable variances of the actual lining concrete power of resistance from design value have been revealed, as well as local destructions of a lining and internal voids. It has been estimated that influence of lining concrete resistance power nonhomogeneity leads to decrease in carrying capacity on average by 17.3%. Consideration of inner and outer defects can reduce the carrying capacity by 2-3 times. While that sort of assessment not always allows to reveal dangerous processes in the considered geotechnical system and to realize effective protection measures promptly. In this case it is reasonable to use information modeling on the basis of BIM technologies. In relation to railway tunnels the further enhancement is needed. The following sequence of engineering status assessment of a tunnel while information modeling is proposed: carrying out essential geotechnical and geophysical researches on the route of a tunnel; tunnel structures monitoring system development and deployment, collection and analysis of data; regular control of a tunnel by the railcar with the measuring station; creation of a tunnel digital model, filling it with data, regular updating and checking calculations; development and implementation of essential repair actions.

Diode-pumped multi-mode graded-index (GRIN) fiber Raman lasers provide prominent brightness enhancement both in linear and half-open cavities with random distributed feedback via natural Rayleigh backscattering. Femtosecond laser-inscribed random refractive index structures allow for the sufficient reduction in the Raman threshold by means of Rayleigh backscattering signal enhancement by +50 + 66 dB relative to the intrinsic fiber level. At the same time, they offer an opportunity to generate Stokes beams with a shape close to fundamental transverse mode (LP01), as well as to select higher-order modes such as LP11 with a near-1D longitudinal random structure shifted off the fiber axis. Further development of the inscription technology includes the fabrication of 3D ring-shaped random structures using a spatial light modulator (SLM) in a 100/140 μm GRIN multi-mode fiber. This allows for the generation of a multi-mode diode-pumped GRIN fiber random Raman laser at 976 nm with a ring-shaped output beam at a relatively low pumping threshold (~160 W), demonstrated for the first time to our knowledge.

Mode decomposition is a powerful tool for analyzing the modal content of optical multimode radiation. There are several basic principles on which this tool can be implemented, including near-field intensity analysis, machine learning, and spatial correlation filtering (SCF). The latter is meant to be applied to a spatial light modulator and allows one to obtain information on the mode amplitudes and phases of temporally stable beams by only analyzing experimental data. As a matter of fact, techniques based on SCF have already been successfully used in several studies, e.g., for investigating the Kerr beam self-cleaning effect and determining the modal content of Raman fiber lasers. Still, such techniques have a major drawback, i.e., they require acquisition times as long as several minutes, thus being unfit for the investigation of fast mode distribution dynamics. In this paper, we numerically study three types of digital holograms, which permits us to determine, at the same time, the parameters of a set of modes of multimode beams. Because all modes are simultaneously characterized, the processing speed of these real-time mode decomposition methods in experimental realizations will be limited only by the acquisition rate of imaging devices, e.g., state-of-the-art CCD camera performance may provide decomposing rates above 1 kHz. Here, we compare the accuracy of conjugate symmetric extension (CSE), double-phase holograms (DPH), and phase correlation filtering (PCF) methods in retrieving the mode amplitudes of optical beams composed of either three, six, or ten modes. In order to provide a statistical analysis of the outcomes of these three methods, we propose a novel algorithm for the effective enumeration of mode parameters, which covers all possible beam modal compositions. Our results show that the best accuracy is achieved when the amplitude-phase mode distribution associated with multiple frequency PCF techniques is encoded by Jacobi–Anger expansion.

Diode-pumped multi-mode graded-index (GRIN) fiber Raman lasers provide prominent brightness enhancement both in linear and half-open cavities with random distributed feedback via natural Rayleigh backscattering. Femtosecond laser-inscribed random refractive index structures allow for the sufficient reduction in the Raman threshold by means of Rayleigh backscattering signal enhancement by +50 + 66 dB relative to the intrinsic fiber level. At the same time, they offer an opportunity to generate Stokes beams with a shape close to fundamental transverse mode (LP01), as well as to select higher-order modes such as LP11 with a near-1D longitudinal random structure shifted off the fiber axis. Further development of the inscription technology includes the fabrication of 3D ring-shaped random structures using a spatial light modulator (SLM) in a 100/140 μm GRIN multi-mode fiber. This allows for the generation of a multi-mode diode-pumped GRIN fiber random Raman laser at 976 nm with a ring-shaped output beam at a relatively low pumping threshold (~160 W), demonstrated for the first time to our knowledge. [ABSTRACT FROM AUTHOR]

The aim of the article is to study the structure and dynamics of Ukraine’s foreign trade under the influence of cyclicality of the global economic system development. There analyzed reasons for the predominance of primary sector goods in the structure of Ukraine’s production, which causes a relatively high seasonal volatility of the economic growth rates. The raw material orientation of Ukraine’s exports explains the instability of the Ukrainian economy regarding the fluctuations of the world market conjuncture. Ukraine’s critical dependence on the cyclical fluctuations of the global economic system manifested itself in 2009, when the adverse conjuncture of the world prices for metals and commodities led to a sharp decline in the production volumes in the national economy. It is concluded that the possible ways of solving the above problems in the national economy of Ukraine is the modernization and restructuring of industrial production, increase in the production volumes of goods for domestic consumption, technological and organizational renewal of the fixed assets of manufacturing enterprises, as well as reorientation of the Ukrainian industry to producing goods with a higher degree of processing along with increasing the share of high-tech products in the total exports.

The Belukha Mountain is the highest peak of the Altai. On July 26 (7th August in the new time scale) of 1914 the brothers Boris and Mikhail Tronov discovered the mountain and were the first people to climb it. The Tronov Glacier is named after them. The Belukha glacier plexus is now subject to intensive degradation caused by current climate warming. There are changes in the processes of ice-forming, the temperature regime, and the stratigraphic characteristics. The mountain slope processes have become more active. The glacier length has decreased by 1.5–2.0 km, their area shortened almost by 20%, and the volume – by 10–12%. The snow-coverage of slopes has decreased, and positions of the ice-forming zones have correspondingly changed. Analysis of cores from the borehole drilled by the international expedition of 2003 on the west plateau of the Tronov Glacier has made it possible to better refine the character and seasonality of the glaciers alimentation. It is supposed that 11 thousand years ago no glacier existed here.The glacier plexus of the Belukha Mountain area is a natural reference point to monitor the state of glacierization and to justify predicted glacio-climatic situations. We propose to organize an international project aimed at the monitoring of these glacier areas and then to prepare a joint monograph devoted to its glacio-climatic characteristics. This could be performed in the framework of the Russian-Kazakh international programs with participation of scientists from other countries. Now is the right time to prepare summarizing monographs on glacierization of the main glacier clusters in the Russian mountains, similar to the series of books on representative glacier basins in USSR published in the 1980s. The Belukha glaciers should certainly be included in this series.

This effective, robust protocol generates glass coverslips coated with biotin-functionalized polyethylene glycol (PEG), making the glass surface resistant to non-specific absorption of biomolecules, and permitting immobilization of biomolecules for subsequent single-molecule tracking of biochemical reactions. The protocol can be completed in one day, and the coverslips can be stored for at least 1 month. We have confirmed that the PEG surfaces prepared according to the protocol are resistant to non-specific adsorption by a wide range of biomolecules (bacterial, mitochondrial, and human transcription factors, DNA, and RNA) and biological buffers.

Статья посвящена исследованию резонанса, который победа Германии над Францией в 1940 г. вызвала в Советском Союзе. Автор уделяет особое внимание реакции советских военных кругов, которые, по его мнению, были среди первых, кто осознал стратегические перемены после падения Франции. Документальные источники, цитируемые в работе, отражают мнения как командования, так и рядовых солдат.

Research has been conducted on the bacterial RNA polymerase holoenzymes. The use of the fluorescence energy transfer and distance-constrained docking in identifying the tree-dimensional structure of this holoenzyme and the open complex of the bacterial RNA polymerase-promoter in solution is discussed.

The RNA polymerase (RNAP)-promoter open complex and its structure and organization are discussed. Systematic site-specific protein-DNA photocrosslinking has been used to find out about interactions between bacterial RNAP and promoter DNA in the RNAP-promoter open complex that functions as a catalyst. More than 100 defined crosslinks between individual assessments of RNAP subunits and individual phosphates of promoter DNA have been mapped.