This article discusses the economic approach to the choice of the mode of continuation of the system in the face of partial failure. It discusses strategies related to the continuation of work in conditions of partial failure or cessation of operation until the completion of the operational restoration process. The characteristics of each of the strategies are presented in a comparative aspect for the continuation of the operation of the object in the post-failure period or the delay in operation for the duration of the restoration. The dependence of the time recovery parameters and the times defining the moment of identifying a partial failure in the coordinates of the time axis from the beginning of the working cycle to the next scheduled maintenance has been revealed. The resulting mathematical expressions allow, under certain conditions, to justify the choice of one of the two strategies considered. For more complex cases, it is proposed to use expert approaches to take into account additional characteristics of the process, such interregional period, performance and acceptable risks associated with working in conditions of partial failure. The article provides graphs illustrating the change in reliability characteristics in two ways of developments of events related to the adoption of a decision to continue work.
Keywords: partial failure, the coefficient of gain in terms of work, the probability of uptime, recovery time, time in the post failure period
The process of analysis and modeling is proposed to be carried out in three stages: determinism, stochasticity and adaptability. The essence of these stages is revealed. The authors highlight the problem of predicting changes in partial failure, affecting the state of the technical system. The main distinctive features of such a refusal from the full (partial loss of working capacity, reducing the number of functions performed, and others) are shown. A diagram of the development of possible degradation processes in a technical facility as a result of partial failure is presented. Transitions to the states of several consecutive partial failures or transitions to a complete failure after one or several partial ones are possible. With getting into a state of complete failure, the object is fully restored. Developed proposals for the sequence of operations for the identification of failures at the level of the generalized algorithm. An illustrative example considers a fragment of the transition of a partial failure to another partial failure, which develops into a complete failure with the impossibility of further functioning of the electric machine for its intended purpose. The conclusion is made about the need to use expert systems and assessments for making decisions about functioning in conditions of partial failure.
Keywords: partial failure, critical failure, degradation change failure, diagnostic task, electric machine
The problem of recognition of defects in the surface layer of polished raceways of bearing rings according to the fractal dimension of the signals of the eddy current sensor is considered
Keywords: fractal dimension, defect recognition, recognition algorithm
Aspects of determination of pressure losses in local resistances at hydraulic calculation of underground polyethylene gas pipelines are considered. Calculation of coefficient of local resistance of saddle branch of firm FRIALEN (Germany) is resulted. The analysis of the dependence of the local resistance coefficient on the geometric parameters of the main gas pipeline and the gas pipeline-input is given.
Keywords: gas pipeline, hydraulic calculation, pressure loss, coefficient of local resistance, gas consumption, geometrical parameters
The main disadvantages of the methods of diagnosing the cylinder-piston group used at present are indicated in the article. Mathematical dependencies and the technique of technical diagnosing of a cylinder-piston group of diesel engines with a cold starting cranking of a cranked shaft developed on their basis are offered.
Keywords: engine, cylinder-piston group, compression,diagnosis, cold idle cranking of the crankshaft
The relevance of the research efficiency of known mechanization variants of concrete works during the construction of multi-storey buildings with monolithic frame is justified in the article. The data about the areas of rational choice specified and fulfilled by the authors, advantages and disadvantages of such methods are generalized and systematized. The features of the peculiarities of three of them, the most significant for the research are considered in detail. At the same time the results of the evaluation of their effectiveness in terms of unit labor and financial costs in the construction of frames of single-section tower-type buildings are presented, making it easier to optimize the choice of appropriate solutions in the organizational and technological design.
Keywords: monolithic frame building, concrete works, mechanization variants, efficiency, unit labor costs, unit financial costs
The legal status of water bodies implies special measures aimed at preserving and preventing negative processes within the boundaries of a water body. A zone with a special mode of use is the territory, within the boundaries of which the mode of using the object for the purpose of protection and (or) to protect the environment is established. In modern geodesy, special satellites are used that are part of the global positioning system. The object is tied to the existing geodetic network, the identification marks are laid in a minimal amount, then aerial photography is performed and the photoplans are “stitched”. The emergence of electronic and unmanned measuring instruments during a complex of geodetic works greatly facilitated the work of geodetic engineers, allowing them to increase the productivity and accuracy of work performed when using such instruments.
Keywords: water protection zone, zones with a special mode of use, water bodies, unmanned aerial vehicles, coastline, coastal protective strip, aerial photography, GNSS receivers, surveying equipment, orthophotomap
This article describes problems of ensuring the reliability of gas pipelines, one of which is connected with the construction of the North Seas on the shelf in the zone of permafrost soils, the other with the construction of long-distance gas pipelines in difficult hydrological conditions. Were analyzed the existing technical solutions in the light of the above construction conditions. Were revealed the advantages and disadvantages of the considered technologies of construction and transportation of gas are. The research identifies the main factors affecting the reliability and efficiency of design solutions for the construction of gas pipelines in areas with difficult hydrometeorological conditions.
Keywords: reliability of gas pipelines, analysis of technical solutions, complex hydrometeorological conditions, gas transportation
The approach to construction a computer model of a functional information converter based on element-wise operations with multidimensional tables of numbers is investigated. A numerical decision-making algorithm based on infinite-valued logic was built and verified (in particular, fuzzification, implication, aggregation, defuzzification algorithms). The mathematical, algorithmic and software model of fuzzy decoder of the positional bipolar code in a single-unit one is investigated. The transition from the initial model given in terms of three-valued logic to a similar system having an infinite logical basis is shown. The numerical algorithm has been tested and debugged in the GNU Octave mathematical computation package environment with minimal use of functions from the fuzzy-logic toolkit.
Keywords: decoder, single-unit code, functional converter, infinite-valued logic, t-norm, fuzzification, defizzification, implication, aggregation, three-valued logic, bipolar code
The article is devoted to the description of the method of forming steganographic network messages using the ICMP service protocol for their hidden transfer, bypassing restrictions of firewalls and other computer network protection systems. It describes the functions of the ICMP protocol, its advantages when used in steganography tasks, and the specifics of processing ICMP packets by operating systems and intermediate network equipment. Special attention is paid to the practical implementation and application of the proposed method. It describes the network utilities for working with packages and an example of their use for transmitting a hidden message. For the software implementation of the network steganography method, it is proposed to use the C # programming language and the SharpPCap and Packet.NET libraries, for which the article contains examples of use and the necessary parameters for forming packets with steganographic messages.
Keywords: information security, network steganography, ICMP protocol, TCP / IP stack, encapsulation, SharpPCap
The concept of “partial failure” used in practice is analyzed as a state in which the possibility of continuing the operation of a technical device remains. It is argued that partial failures are widespread in the operation of technology, but unlike full failures, under which the continuation of work becomes impossible in any mode, not fully understood. A number of reliability indicators are proposed that take into account the specifics of partial failures and the possibility of continuing work when they occur. Attention is drawn to the fact that the decision to continue the operation of the device in the presence of a partial failure is associated with risks. The essence of the risks lies in the possibility of receiving damage in the form of further deterioration of the technical condition of the partially failed device. However, in many cases such a risk may be justified. The task of deciding on the continuation of the operation, in the conditions of a partial failure is a complex task of system analysis. Its solution will require the use of complex models compiled using modern methods of mathematical descriptions and research.
Keywords: partial failure, reliability theory, reliability indicators with partial failure, risks of continued operation, making decisions on continuation of operation
The paper contains an analysis of the results of experiments on obtaining radiative structures based on gallium antimonide, formed by the method of thermal melt migration in a semiconductor matrix. The epitaxial process modes within the selected range were optimized for such parameters as the wavelength corresponding to the fundamental transition, a small lattice discrepancy, a small discrepancy in the coefficients of thermal expansion of the growing TP and the matrix. An original effect is described - an increase in the solubility of the Bi content in solid solutions, isoperiodic binary compounds A3B5 under conditions of a gradient temperature field. This effect allows a wide variation in the optical parameters of the element base of instruments based on solid solutions of GaSbBi / GaSb. The mechanisms of the generation of dislocations in a crystallized solid solution and the features of electrophysical and photoelectric parameters are analyzed. A structural solution of a light-emitting diode with strip geometry is proposed.
Keywords: solid solutions, recrystallization, gradient liquid-phase epitaxy, thermomigration, indium antimonide-bismuthide, melt thickness, temperature gradient, components, growth coordinate, epitaxial layers
In this paper, the modeling of phase equilibria in multicomponent systems of A3B5 compounds was carried out and the compositions of the liquid phase equilibrated with a given solid solution were calculated. A model of excess thermodynamic functions is used, which takes into account the formation of associates in the melt near the solidus temperatures. The developed algorithm allows solving a direct problem (in which the input parameters are the growth temperature of the layers and the composition of the solid phase corresponding to the expected instrument characteristics) and the inverse problem (the growth temperature and composition of the solid solution are sought for the given liquid phase). The limiting concentrations of the alloying components, arsenic and bismuth, are determined. The structural and electrophysical characteristics of multicomponent semiconductor A3B5 heterosystems are discussed, the solid solutions of which crystallize from the liquid phase in a gradient thermal field. The mechanism for introducing impurities into the lattice of epitaxial layers of multicomponent solid solutions is described for the first time. With an increase in the thickness of the crystallizable film, the thermodynamically equilibrium substitution by antimony bismuth atoms is completed and the introduction of Bi atoms into the interstices takes place. The interaction of neighboring atoms with the valence electron shells of Bi becomes more symmetrical, which causes an increase in concentration. The concentration of film defects near its rear surface also increases. The obtained values of electrophysical parameters make it possible to draw a conclusion about the instrumental suitability of the materials under study.
Keywords: solid solutions, mesostructure, antimonide, alloying, liquid phase, phase transformations, binary compounds, associates, lattice constant, multicomponent systems
The paper is devoted to the actual problem of ensuring the information security of web-sites. It discusses a method for detecting intentional threats to the confidentiality of information as a result of unauthorized access and is manifested in the form of atypical requests to resources by users. The paper proposes a method based on data mining. Its essence lies in the classification of users' behavior on the basis of information about their actions using an artificial neural network. As a basis for the implementation of the proposed tools, site security audit tools are used as a source of information. The structure of neural network, training methods and practical application are described, and the effectiveness of the proposed methods is evaluated.
Keywords: Data mining, artificial neural network, web-design, machine learning, classification
The paper presents the characteristics of wind and solar resources of the Southern Federal District on the basis of which the assessment of the prospects for introducing innovative innovations such as perovskite photovoltaic cells and Vertical-axis wind turbines into the process of district energy production is given.
Keywords: Vertical-axis wind turbines, alternative energy source, wind power, wind turbine, renewable energy source, perovskite photocell, solar battery, solar energy, energy resources of the Southern Federal District, energy saving