The article discusses the most common types of modified columns in Mexico: composite section columns, high-strength concrete columns, prestressed concrete columns. The procedure for calculating columns and new proposals to improve construction efficiency is described. Columns are one of the most important elements of orthogonal frame buildings, so improving their designs requires special attention. In composite section columns, using high-strength concrete in the outer zone, the strength of the concrete located in the core increases 1.5 times more, which significantly increases the efficiency of the structure. Columns made of high-strength concrete have an increase in efficiency when used in high-rise buildings. Prestressed concrete columns are very effective because they have high resistance to load, they are able to withstand significant stresses.
Keywords: concrete, reinforcement, reinforced concrete, high-strength concrete, prestressing, columns, columns of composite section, eccentricity, stress, deformation
The article considers issues on the arrangement of the urban environment in terms of the integrated development of urban areas. The principles of competent formation of pedestrian spaces are formed thanks to the formed pedestrian spaces of European cities. The ways of development of the urban environment of the city of Dmitrov, Moscow Region, for the attractiveness of the urban environment, improve the condition and aesthetic perception of the territory are indicated.
Keywords: Moscow region, landscaping, urban environment, pedestrian zone
This article deals with the hydrophone antenna arrays (the results of studying are applicable to radio-frequency aerials as well) the elements of which are connected in parallel on one coordinate (in the columns). The mathematical models had been developed which were derived from the formula of the directional characteristic of a right-angled flat radiator embedded into the absolutely hard baffle. A level of overshoots of the directional characteristic (as related to a principal maximum) amounts approximately 0.3; a coefficient of decreasing overshoots of the directional characteristics because of shifting lines is approximately equal to 1.4 for the array (8 x 8 or 16 x 16) with a pitch equal to wave length, with shifting lines to half the array pitch, a gap between the elements is 0.1 of the array pitch and a direction of beams is not more than 15 degrees on both sides with respect to the normal to an antenna plane. Without the gap between the elements at the abovementioned conditions the overshoots and the coefficient of their decreasing will be approximately equal to 0.2 and 1.6 respectively. Thanks to extending the antenna array pitch a number of antenna elements is being reduced, and consequently, a number of the receiving channels and power amplifiers will be reduced as well. The simulation results are presented including computed two-dimensional directional characteristics of the antennae. The overshoot dependences upon beam direction and antenna array element dimension are also shown.
Keywords: antenna, element, array, array pitch, element pitch, directional characteristic, side-lobe level, narrow sector of scanning, increasing of array pitch
The article considers the effect of Al2O3 loading on the physical and chemical properties of cobalt catalysts. The loading of the alumina additive has a significant effect on both the phase and texture properties, as well as on the cobalt reduction process in the composition of the studied samples. It was found that with increasing loading of the additive, the specific surface area of the catalysts decreases, and the cobalt recovery process slows down.
Keywords: Fischer-Tropsch synthesis, catalyst, cobalt, alumina, promoter, temperature programmed reduction
The article describes the design of the integral micromechanical sensor of linear accelerations of the capacitive type; A construction method is briefly described using the self-assembly operation based on controlled self-organization of mechanically stressed semiconductor GaAs / InAs layers. The design of the capacitive accelerometer was modeled in the CAD system ANSYS, where static and modal analysis were performed. The results of mathematical modeling meet the requirements of modern micromechanical accelerometers, and allow them to be used for the further development of structures of this type. The obtained data can be used in particular for calculating the recommended parameters in the development of methods for designing capacitive sensors of angular velocities and linear accelerations and for developing more accurate models of MEMS structures.
Keywords: MEMS, microelectromechanical system, accelerometer, modeling, design, sensor, sensor, mathematical model
The paper discusses the problems of predicting the growth regimes of quasi-one-dimensional electronic structures - quantum nanowires based on three-component compounds A3B5. It is shown that modeling of growth processes of threads based on the Monte Carlo method can be an effective solution. The formation of quantum nanowires is carried out due to the external flow of particles transferred in the first series of experiments perpendicular to the substrate, in the second series - at random angles. The constructed model allows us to evaluate the effect of the composition on the geometric parameters of the formed objects. The critical thickness of quasi-one-dimensional structures is calculated. Conclusions are drawn about the control factors of the processes of thread growth. It is shown that compositional variations are an effective parameter for controlling the processes of formation of three-component 1D structures.
Keywords: quantum nanowires, Monte Carlo method, growth on a substrate, adsorption, diffusion, one-dimensional structures
The paper studies the liquid-phase epitaxy processes of a new material of infrared optoelectronics - indium arsenide doped with bismuth using a stepwise thermal field. An analysis of the phase equilibrium during the growth of a solid solution is carried out. The possibility of the formation of a mesostructure (modulation of the composition along the growth coordinate) is shown. The problems of defect formation in composite layers grown from a melt are considered. Ways of decreasing the dislocations density in gradient layers are discussed. A relatively simple method for controlling the thermal field of temperature in the crystallization zone and a new technological procedure for the sequential crystallization of solid solutions with a mesostructure have been developed.
Keywords: solid solutions, liquid-phase epitaxy, indium arsenide, mesostructure, stepwise thermal field, dislocation generation
The paper analyzes the use of Arnold transform for digital image scrambling. The proposed algorithm is implemented as part of the developed Luka library of medical image processing in the DICOM format, and provides additional cryptographic and steganographic protection of the patient’s personal data. The issues of evaluating the effectiveness of the developed software module using the structural similarity index are considered.
Keywords: Arnold transform, scrambling, peak signal to noise ratio, standard deviation, structural similarity index, DICOM, SSIM
The article describes the technique of resource-intensive (in terms of computing resources) and accurate assessment of the thermal mode of electron-ic equipment. The method involves the consist use of software packages “AN-SYS” and “ASONIKA–TM” to calculate temperature pattern that occurs dur-ing operation of the device. Accounting result in “ANSYS” is used as a thermal boundary condition of the first kind for the calculation in “ASONIKA–TM”
Keywords: thermal processes, heat exchange, control system, launch vehicle, finite element method, FEM, ANSYS, ASONIKA – TM
The article is devoted to the collection and processing of data for training a predicting model of road accidents involving pedestrians.To identify the factors affecting the accidents was analysed of statistical information taken from the "Open Data Portal of the Moscow Government" and the portal "Safe Roads.RF", as well as from the accident cards on traffic police website.
Keywords: traffic accident, data analysis, pedestrian safety, machine learning, gradient boosted decision trees
The advantages of using frequency converters are well known. First of all, this is a significant energy savings due to the regulation of the rotational speed of the electric motor. In addition, ensuring a smooth frequency start using frequency converters significantly reduces thermal and mechanical loads when starting synchronous motors with a rotor excitation winding and with permanent magnets. In this paper, the start-up of a synchronous motor with a two-link frequency converter for various types of load was investigated. The following issues were considered: - creation of a three-phase two-link frequency converter model for a synchronous drive; - calculation of the torque on the shaft at rated power, as well as coefficients reflecting the nature of the load; - simulation of the start-up and operation of a synchronous motor and a two-link frequency converter with fan, conveyor and constant shaft loads. In conclusion, the model of a two-link frequency converter with a synchronous motor, which was researched in this paper, can be used in systems where the considered types of loads are used. This circuit has high energy characteristics, reliability and stability, and is also able to reduce the amplitude values of currents and time of transient processes at start-up
Keywords: two-link frequency converter, permanent magnet synchronous motor, mathematical model, reliability, PSIM
This paper describes the methods used to take into account the nonlinearity of magnetic processes in the steel of an electric asynchronous machine. This is required for some cases when these physical processes play an important role in the accuracy of data. Justifications are presented that prove the need to approximate the magnetization curve of asynchronous machines to improve the quality of regulation of the electric drive, as well as improve control by energy criteria. Work at full load or near it leads to a decrease in the magnetization EMF due to a voltage drop in the stator, this must be taken into account. The article also shows the approach of applying the methods of accounting for saturation in synchronous machines for asynchronous using transformed equations.
Keywords: induction motor, electricial drive, vector control, saturation curve fitting
This article provides an overview of scientific papers that describe the use of machine learning methods for various tasks in rehabilitatin medicine. Examples of studies and their main results are given. At the moment, a simulator for wrist joint restoration is being developed. The use of simulators to restore the hand can be associated with the finger movements determination on a healthy hand. This problem requires a classification of movements and can be solved by using machine learning. This article presents the results of the development of classifiers for determining finger movements. The following methods were used: logistic regression, the support vector machine, and the neural network. The database obtained by using electromyographic sensors was used to train and test the models. Classification results are also compared with the results of original studies. The most effective method for classifying finger movements was selected and justified.
Keywords: rehabilitation, machine learning, neural networks, classification of movements, wrist simulator
A model of a household refrigeration machine (BHM) is considered. The refrigerating capacity, thermal load are determined, the compressor and operational parameters are calculated, the cycle of the chiller in p-i coordinates is built.
Keywords: household refrigerator, temperature, refrigerator, heat load, cooling capacity, compressor, heat influx
Based on the mathematical models describing the equally forgetful robots with equivalent emotions, we introduced the definition of elementary education of human digital twins. Method for calculating the parameters of such education was created. This technique is based on experimental data. At the paper at hand, we proposed methods for calculating the coefficients of soft and hard psychological influence of digital twins on each other as a result of their communication. Computer program for calculating these coefficients was described.
Keywords: robot, mathematical modeling, human digital twin, robot interaction, psychological influence, robot emotional training, group of robots, computer program, psychological experiments, processing of experimental results
The paper presents a solution to the problem of photographic input metrological control of industrial products based on the method of structural approximation synthesis and analysis of one-dimensional structural images. Mathematical models of structural images, algorithms for their synthesis, analysis and interpretation of processing results are described. The results of experimental testing of the proposed algorithms are presented, allowing to evaluate their computational efficiency and reliability of the metrological control procedure.
Keywords: metrological control, image processing, pattern recognition, structural approximation method, dynamic programming
This paper describes the problems of identifying effective sales channels for services working with a call center. The solution is presented in the form of a multi-level model of sales channels that works with call tracking with a limited number of phone numbers. This approach can be applied in services of small and medium-sized businesses, which cannot afford a large number of phone numbers for call tracking.
Keywords: sales channel, contextual advertising, call tracking, call center, marketing, Yandex Direct, Google AdWords
A new classification of methods for constructing Voronoi graphs on maps represented by point and polygonal obstacles is proposed. Based on the topology of space, it is proposed to classify the constructed Voronoi graphs as external and internal. Thus, Voronoi graph construction methods can calculate either one of the presented types of Voronoi graphs, or both types. The introduced concepts and the proposed classification will be useful for robotics researchers using the Voronoi graph method when planning the path of mobile robots in various environments.
Keywords: Voronoi graph, classification, Voronoi diagram, weighted graph, topology
The paper demonstrates the objective need of improvment of information security systems in terms of development of information and telecommunications equipment. The theorems that describe the properties of parametric solutions of multigrade diophantine equation systems (MDES) is presented. The properties are used to develop information security system mathematical models. Also the paper demonstrate generalized Frolov's theorem and author's theorem to enable development information security system mathematical models with Diophantine problems. Author's alphabetical information security system mathematical model in form of tuple is given. Approch to develop disymmetric bigramm information security system (DBISS) based on two-parametric solutions is given. The approach generalize establishing open-key information security system. The direct and inverse transformations is realized through parametric solution that provisionally divided into two parts - for direct transformation and inverse transformation. Also author introduces new concept of equity of number ordered set or set of parameter with given dimension and grade. The DBISS mathematical model is given in the paper. The model is based on the MDES two-parametric solution with given dimension and grade. The decribed mathematical model demonstrate the potentil of diophantine equations to development of information security systems with high reliability.
Keywords: information security system, symmetric cryptosystem, disymmetric cryptosystem, open-key cryptosystem, ecncryption, decryption, multigrade diophantine equation system, parametirc solution, diophantine problems
Information models are successfully used in construction when developing archi-tectural and planning solutions, as well as when performing building elements cal-culations. Information models of organization processes and construction produc-tion technologies have not found their place in the system of BIM technologies. In this regard, the formation of approaches to the construction of information models of the processes of construction of buildings and structures should be attributed to the current issues of construction science. The main focus of the work is on the discrepancy between the processes of scheduling and determining the estimated cost in the process of preparing project documentation for construction. The pur-pose of the work was to develop the principles of building an information model for the formation of Executive documentation established by the legislation of the Russian Federation for the construction of capital construction projects. In the process of achieving the goal, the author solved the problems of systematization of problems of organizational and technological design and formulated the principles of building information models describing the process of construction of structures of buildings and structures, which are used for forming acceptance certificates. As a result of the research, the author comes to the conclusion that it is necessary to introduce the codes of the classifier of construction resources into the practice of organizational and technological design and estimate calculations. At the same time, codes of the classifier of construction resources should be applied at the stage of development of architectural planning and design solutions.
Keywords: information model, construction process, organizational and technological design, building resource classification codes, reporting documentation in construction, work log, calendar plan, network plan
In the article, the authors consider the influence of the seasonality factor on the architectural and planning decisions of hotel buildings on the Black Sea coast of the Krasnodar Territory. The climatic and socio-economic conditions of this region are revealed. The operating modes of buildings dictated by climatic characteristics are determined. The optimal solution for this region is a year-round building with seasonal expansion. The authors describe the solutions of hotel rooms and public spaces, taking into account seasonal changes in capacity, purpose of the room, climatic and other factors.
Keywords: seasonality, architecture, hotel, adaptability, recreation, transformation, design, mobility, climate, leisure