The requirements for the creating information system automating the linguistic center activities are analyzed and optimized. The first and second stages of IP creation Life Cycle are presented. The analysis of the subject area and the design of the information system using the tools and methods of the object-oriented approach is carried out. Using such CASE tool, as the RationalRose, UML diagrams describing the activities of the Language Link linguistic center are constructed. By means of AnyLogic, simulation modeling was carried out and a student testing model was developed to determine the level of language proficiency in order to choose the exam category. The requirements for the projected information system of the linguistic center are formulated. Logical and physical ERD models of the database structure are constructed using the ERWin CASE tool. The design of the user interface of the information system for the linguistic center has been also carried out.
Keywords: domain analysis, design, information system, object-oriented approach, modeling, simulation model, UML language, CASE tool, UML diagram, ERD diagram
One of the most promising unmanned aerial vehicles (UAVs) designs is a single-rotor scheme, however, due to the complexity of the control principles for such aircraft, there are currently no effective methods for automating their takeoff and landing. The use of systems traditional for multicopter UAVs based on satellite positioning and calculation of control actions using strict mathematical formulas does not allow to fully realize the advantages of a single-rotor scheme. The article considers the existing model of the UAVs control process with a single-rotor scheme, proposes and justifies its changes, and also formulates a method for automatically controlling the take-off and landing of a single-rotor robot helicopter.
Keywords: single-rotor scheme, robotic helicopter, automatic takeoff, automatic landing, method, control
This article discusses the development of a universal mobile application "Signal "H"" for people with hearing and speech disabilities based on the analysis of existing mobile applications.
Keywords: fire, mobile application, communication, fire protection units, type of fire, people with disabilities
This article contains the results of a study of the strength characteristics of building mortars of various compositions based on magnesia binder (magnesia oxychloride cement). The results obtained: the final compressive strength (28-day) within the studied compositions is from 12 to 45 MPa, the kinetics (rate) of strength growth on the first day of hardening is from 22 to 38%, on the third day of hardening – 33-68%, on the seventh day – from 50-88%, and about 120% from the design (28-day) with further hardening.
Keywords: magnesia oxychloride cement, magnesia binder, magnesia mortar, magnesia concrete, caustic magnesite, magnesium chloride, compressive strength, strength set kinetics
A periodic semiconductor structure is considered, consisting of tunnel-uncoupled quantum wires (QW) based on InSb containing impurity centers. The uniform magnetic field is directed along the QW axis. For the case of light polarization transverse with respect to the QW axis in the framework of the dipole approximation, in the effective mass approximation, an analytical expression for the impurity absorption coefficient of light is obtained taking into account the dispersion of the QW radius described by the Gauss function. It is shown that on the spectral curve constructed in the Maple program, for given parameters of the QW and the semiconductor structure, there is a sequence of resonant maxima with a doublet structure. The cyclotron frequency determines the distance between the maxima in the doublet, and the frequency of the doublets on the spectral curve is determined by the hybrid frequency. With an increase in the magnetic field, the dynamics of the edge of the impurity absorption band is observed, which can be used to create detectors of optical radiation in a wide range of wavelengths and will make it possible to identify such semiconductor structures. It is also possible to obtain valuable information about the parameters of the QW and the band structure of the semiconductor from the spectral curve
Keywords: impurity absorption coefficient, quantum wire, low-dimensional semiconductor structures, impurity center
For successful training of students in educational institutions, modern laboratory equipment must be present. This equipment should be affordable, small enough to fit in a classroom, easy to maintain and operate, and versatile enough to allow students to conduct research with faculty or on their own. All this indicates the relevance of this work. The purpose of the work is to create original training equipment for seed germination. Work on a new design of educational equipment required to study and generalize the results and experience of using similar equipment known from the state of the art, as well as to study known methods and technologies. In the course of work, using elements of system analysis, new design solutions were found for the layout of universal training equipment for seed germination.
Keywords: germinating table, training equipment, seed germination, seed quality
The support in the bottom-hole zone of the trunk is a system of rings made of monolithic concrete having a different hardening period, which increases from the face up the trunk and is determined by the duration of the tunneling cycle. The strength and deformation parameters of the concrete support depend on the age of the concrete. Thus, to determine the strength of concrete in the early stages of concrete hardening, various empirical dependencies are used that link the strength of concrete at the design age with the strength at the required age. Based on a series of calculations performed by the finite element method, it was found that the change in the penetration rate does not significantly affect the relationship between stresses and deformations when static equilibrium is reached in the ""support – array"" system, which occurs at a high penetration rate at a greater distance from the bottom of the trunk. At the same time, intensive loading of the support at an early age can disrupt the process of natural hardening of concrete, lead to a violation of its structure, the development of fracturing, which will entail a decrease in the bearing capacity and water resistance of the support, a decrease in its durability.
Keywords: shaft, sinking, support, concrete, stress, deformation, strength, bearing capacity
This article discusses the modeling of a 4th order Butterworth bandpass filter, with the Sallen-Key topology, composed of 2 stages with a bandwidth from 31.5 Hz to 8.5 kHz, designed to work as part of a digital noise level meter . Modeling was carried out in a modern computer-aided design package Filter Design Tool from Texas Instruments. The simulation results are presented, a conclusion is made about the correspondence of the parameters of the simulated filter to the calculated ones. The filter has a satisfactory quality factor, amplitude deviation in the passband, is quite simple and economically acceptable from the point of view of its implementation.
Keywords: noise meter, bandpass filter, Butterworth filter, Sallen-Key topology, modeling, CAD
The author carried out the development of the measuring unit of the intellectual system for the protection of the territory. Based on the review of devices of a similar purpose, a block diagram of the device was developed. A functional diagram of the developed device based on the block diagram has been developed and described. The description of the computer experiment on modeling the operation of the input block of the circuit in Micro-Cap, its results and analysis is given.
Keywords: measuring unit, intelligent system, modeling, vibration, triboelectric sensor
in the course of designing a device for measuring the instantaneous velocity of plasma in an electrodynamic accelerator, a block diagram of the implementation of the developed method was developed. A mathematical description of the calculation of the instantaneous velocity of plasma in an electrodynamic accelerator is presented. The choice of a realizable method for measuring the instantaneous velocity of plasma in an electrodynamic accelerator using a differential-total-ratiometric coordinate function and approximating the position sensor signal by an inverse-exponential function is substantiated. Simulation of the computing unit of the device in the Micro-Cap environment has been completed.
Keywords: measuring device, electrodynamic accelerator, plasma velocity, differential sensors
The relevance of this study lies in the fact that the mutual influence of existing transport facilities and the newly erected underground part will be taken into account and the ways to minimize the geomechanical impact on each other will be determined. The subject of the study is the stress-strain state of the system ""structure - massif - structure"". The purpose of the study is to minimize the mutual influence of the subway, the railroad and the underground part of the designed building.
Keywords: geotechnical screen, mathematical modeling, FEM, underground structure, mutual influence, stress-strain state, subway station, minimization of influence
The article is devoted to assessing the influence of errors in the experimental determination of initial data by non-destructive methods for recalculating the bearing capacity of building structures. When conducting an inspecting procedure the technical condition of the building structures that have been in operation for a long time, one of the main tasks is to determine their current operational suitability and predict their durability. The author considers possible errors or inaccuracies in the measurements of the physical, mechanical and geometric characteristics of a reinforced concrete beam (concrete class and reinforcement parameters). The degree of their influence on the change in the bearing capacity of the beam is compared. The conclusion is made about the greatest influence on the actual value of Mult (up to 34.5%) occurs from an incorrect determination of the diameter of the working reinforcement. Errors in determining the class of concrete remain within 1%; accuracy of determining the thickness of the protective layer - within 1.5% and they have a significantly smaller impact on the value of Mult.
Keywords: inspection of existing structures, methods of non-destructive testing, calculating of bending structures, reinforcement parameters
In this paper, we study the process of heat conduction in a flat wall with an internal heat source under boundary conditions of the first kind. Various numerical and analytical methods are used to solve heat transfer problems. Each method has a number of advantages and disadvantages. The paper proposes to use the numerical method of finite differences. The original differential equation, as well as the boundary conditions, are approximated using a finite difference scheme. The essence of the method is to apply a spatiotemporal grid to the computational domain. For each grid node, a difference relation is written (the original differential equation with boundary conditions is replaced by the corresponding expressions obtained using the difference scheme). Solving this scheme, we obtain the temperature values in the plate for each step in time and coordinate. On the basis of the solution obtained, graphical dependences of temperature on time and coordinates are constructed, and their analysis is carried out.
Keywords: finite difference method, thermal conductivity, plate, internal heat source, boundary conditions of the first kind
3D printing (3DP) is considered an innovation that promotes automation in civil engineering and offers advantages in design, sustainability and efficiency. With its potential to automate, eliminate formwork, reduce construction waste and improve geometric accuracy, 3DP has promising applications in the building construction and civil engineering. 3DP is an effort to put digital manufacturing into practice, enabling a direct transition from building design / modeling (BIM) to 3DP. This article provides various aspects of application in construction, materials and their compositions, as well as examples of the use of 3DP: buildings, structures, polymer sleepers, etc.
Keywords: 3D technologies in civil engineering and construction, materials
According to available literary and graphic sources, the components of urban space, its structural units and their methods of formation are analyzed. The possibility of forming public spaces inside buildings and structures by methods of forming urban spaces is revealed.
Keywords: space, microspace, mesospatial, macrospace, methods of formation, urban structure, public space, levels of spatial organization, public structure, formation of a public complex