Methods of computer formation of the equations of motion of multibody systems with a tree structure and algorithms for their reduction to the normal form of ordinary differential equations are considered. The equations of motion are written using Hamilton's formalism for an extended set of state variables of a mechanical system. The equations are presented in a compact visual form. Recursive formulas for determining all coefficients of equations are written out. Algorithms for reducing these equations to Hamilton equations in generalized coordinates and generalized momenta are presented. An algorithm for solving the obtained equations of motion for multibody systems using the LTDL-elimination is presented. Formulas are written that allow one to calculate the amount of arithmetic operations required to bring the equations of motion to normal form using the considered algorithms. On the basis of these formulas, a comparative analysis of the efficiency of algorithms for rigid bodies systems of various structures and with various types of connections between bodies is carried out. The results of the analysis are presented in the form of diagrams. The diagrams highlight areas in which the advantage of one or another method is manifested, depending on the type of mechanical system.
Keywords: multibody systems, equations of motion, dynamics, canonical momenta, mathematical modeling, computational efficiency
The article describes an approach to the operation of a data transmission network protection system against computer attacks based on a hybrid neural network. It is proposed to use a hybrid neural network as a machine learning method. To calculate the output value of neural network signals, the activation function is used. The neural network model consists of recurrent cells - LSTM and GRU. Experiments have demonstrated that the proposed network protection system for detecting computer attacks based on an assessment of the self-similarity of the system functioning parameters using fractal indicators and predicting the impact of cyber attacks by applying the proposed structure of the LSTM neural network has a sufficiently high efficiency in detecting both known and unknown spacecraft. The probability of detecting known spacecraft is 0.96, and the zero-day attack is 0.8.
Keywords: data transmission network, computer attack, neural network, protection system, network traffic, auto-encoder, accuracy, completeness, detection, classifier, self-similarity, recurrent cells with long short-term memory
The article contains an analysis of the shallow elastic spherical shell on a rectangular plan, reinforced with ribs along its contour, under the uniformly distributed load. The problem is solved numerically with the variational-difference method, considering the geometric nonlineaity and the shear deformations of the shell and the ribs. As a result, the dependencies of the critical load on the shell stiffness and the ribs stiffness are obtained.
Keywords: shallow spherical shell, ribbed shell, stability, bending stiffness, geometrical nonlinearity, variational-difference method, critical load
The development of a methodology for the formation of an estimate of a construction object on the basis of its information model is considered, taking into account the state of development of software systems for BIM modeling and the peculiarities of regulatory regulation of the construction of construction projects in Russia. The factors that limit the possibility of drawing up estimate documentation for the information model have been identified. Taking into account the identified limitations, a set of operations necessary for the formation of an estimate for a construction object based on its information model is presented.
Keywords: BIM, 5D BIM-model, estimate documentation, civil and industrial construction
This article considers the option of using a simulation model in organizational conflict management as an intelligent analyzer of a conflict situation. It is proposed to build its own style of leadership, necessary and sufficient to successfully overcome the organizational conflict. Based on the model forecast, the manager constructs an appropriate solution within the framework of the variability of authoritarian, democratic and liberal styles of government with the help of the auxiliary variables available to him. This allows him not only to get out of the usual style of leadership, but also to choose the necessary and sufficient style in this case, to test style behavior strategies. The manager has the opportunity to use the management style that best suits the internal and external conditions of his activities. Today, managers must meet the emerging problems and the ability to solve them effectively with their stylistic variability.
Keywords: simulation model, conflict in the organization, management style, behavior strategy, manager
Organizational conflicts are a natural and integral part of any process. In modern control theory, it is proposed to use various adaptive control structures to solve such problems, in particular, with reference or configurable models in the control loop. A cognitive model of adaptive management of organizational conflicts with a configurable model in the management loop is considered. Embedding the model in the control loop allows you to integrate information about the dynamics of process characteristics. Based on information processing, a variant of controls for de-escalation of the conflict is proposed. The model in the organizational conflict management loop is essentially an intelligent conflict situation analyzer. It presents options based on the accumulated and processed information within the framework of known precedents for their solution. The core of such analyzers is a simulation model based on the system dynamics paradigm. The built simulation model allows you to evaluate and predict the impact of factors, ways to stabilize and manage organizational conflicts, taking into account the main parameters. In accordance with the concept of adaptive management, the model can be configured for the current values of the conflict situation parameters and, in accordance with the already tested options, can offer management in a specific situation. The use of the system dynamics paradigm in the model for building an effective forecast is focused on the strategic level of management.
Keywords: cognitive model, simulation model, conflict, escalation, contour, management, de-escalation, organization
A survey of the frame-panel building was carried out, in which ecowool was used as the heat-insulating material. A study was made of the moisture state of wooden frame walls and attic floors. Ecowool samples were taken from various sections of the wall. No mold was detected on material samples. In this case, the sorption humidity was not more than 16%. The results of laboratory tests of ecowool showed high persistence of density and coefficient of thermal conductivity during long-term operation. Tests were conducted to determine the effect of moisture on the change in the physical and technical properties of ecowool. The research results were processed by statistical methods. As a result of the study, it was found that moisture does not accumulate in the ecowool layer of the examined frame walls and attic flooring, but goes out through the insulation and elements of the building envelope. The conducted studies allow us to predict the preservation of the heat-shielding properties of ecowool during operation for a long time
Keywords: ecowool, durability, sorption humidity, density, coefficient of thermal conductivity
The article presents an analysis of promising research on the formation of vibrational mechanochemical coatings from the point of view of practical use in the real sector of the economy
Keywords: combined methods of treatment, vibration treatment, the vibration mechano-chemical (chemical-mechanical) coverage webrevolve technological system, mechanical coating, fragmentary nature, plastic deformation, uniform coating, vibrowave impact, microstructu
This article discusses the process of developing an ultrasonic method of measuring the state of the electrolyte in the process of burning discharge with an electric electrode. The classical methods of electrical effects on the surface of steels, such as electrochemical, electro-erosion, electro-thermal and electro-mechanical have their drawbacks. Namely, high energy consumption, environmental pollution, the problem of recycling by-products, the difficulty of obtaining the required surface profile to a certain extent. In this regard, there is an acute issue of the development and research of new energy-saving, environmentally friendly and cost-effective methods of impact on the surface. At the moment there are no systematic experimental studies of discharge in multiphase media. Not the conditions for the ignition of the discharge with an electrolytic cathode. Not studied physical processes on the boundary of the plasma and the liquid. There is no mechanism of the effect of discharge in the vapor-gas bubble on the surface of metals. All the above reasons delay the development of technology of plasma-electrolyte formation of the surface microrelief. The aim of the work is to measure and optimize the ultrasonic signal and calculate the frequency spectrum of reflected ultrasonic vibrations from a large number of reflectors (electrolyte bubbles), as well as the development of mathematical modeling of the process of reflection of ultrasound from the electrolyte bubbles.
Keywords: Ultrasound; technique; electrolyte; combustion; measurement
This article describes the combined method of plasma-electrolyte processing and subsequent ultrasound imaging of medical needles created from steel grade 12H18N9T. A functional diagram of an installation for medical needles plasma-electrolyte treatment is presented. A device for ultrasound diagnostics of microrelief in the obtained material is described. The actual task of ultrasound medical research is the quality of the processed tip. One of the ways to obtain deformation at the end of the needle is the electrolyte-plasma discharge method at the anode of a given material. In the course of the study, previously obtained results were confirmed, indicating that the plasma electrolyte process was caused by a fivefold or more excess of the cathode area relative to the anode area Sк≥5Sа. A study was conducted of plasma-electrolytic processing of steel grade 12H18N9T using anodic electrolyte. It is shown that in the plasma formation area occurrence around the anode, the current-voltage characteristic is practically independent of the electrolyte concentration. The patterns of formation of the depth of the hole at the end of the needle, determined by the process of melting the surface layer of the anode, which requires a uniform input of heat over a unit of time. The depth of the well and the wavelength of ultrasound are shown. It is necessary to apply roughness (holes) with a size of 10-1000 microns at different angles relative to the axis of the tube with a tip. On the research basis, a unique device «KLYON-1» was created, which performs the material processing and its control by means of ultrasonic radiation.
Keywords: ultrasound, plasma, electrolyte, visualization, microrelief, needle, well
This scientific study presents an analysis of organizational conflicts, as well as problematic aspects of activity in contemporary realities. The effect of organizational conflict on the effectiveness of an individual is shown. The urgency of researching the problem of the activities of the organization’s employees in the context of organizational conflicts, as well as ways to solve them, is given The analysis of the cognitive model. As factors used to reduce tensions in a team, it was proposed to introduce factors for raising qualifications and organizational culture. These factors will influence the target factor - performance. In the course of simulation modeling, it was found that by carrying out activities to improve the skills of employees, measures to increase the level of organizational culture of employees, the organization seeks to reduce tension in the team and, as a result, there is less staff turnover.
Keywords: simulation modeling, cognitive modeling, functional structural analysis, visual analytics, conflict, organization, model, social tension
The article explores various architectural and constructive solutions that ensure the stability of high-rise unique buildings and structures under the action of significant transverse loads arising from strong wind influences. Recommendations are given for choosing constructive solutions for achieving the greatest stability and rigidity of high-rise buildings.
Keywords: high-rise unique building, stability, load-bearing systems, modeling, progressive collapse, structural system, outrigger, skyscraper, column, core of rigidity, strength, reliability, horizontal load
The absorbing apparatus serves to extinguish the impact when the wagons cohere and move. Most of the energy, about 80%, in this system is absorbed by a friction unit consisting of a friction wedge and a fixed plate. Absorption of energy in this system occurs due to the work of frictional forces arising during longitudinal motion of the pressure wedge with respect to the friction plate. Due to the large shock-frictional loads, intensive wear and destruction of the cermet cake occurs, which adversely affects the energy capacity of the absorbing apparatus. To eliminate these shortcomings, studies were conducted to create a new material. After numerous experiments, a composition was obtained with the optimum content of components, which maximally satisfies the working conditions of the friction unit and the requirements imposed on these devices.
Keywords: absorbing apparatus, friction unit, cermet, wear resistance, friction plate, powder material, sintering technology
The article considers the use of renewable energy sources in construction in general and in high-rise unique buildings. Such an approach will allow to design and build buildings in which integrated renewable energy sources can be harmoniously entered into all aspects of construction. This is especially true for high-rise buildings. With the implementation of energy-efficient technologies, the main drawback - high energy consumption - will be cut off. The article analyzes non-traditional sources of energy, such as wind, solar, land, water and biomass. The relevance of their application in construction and influence on all aspects of the project is proved: town-planning, functional, space-planning, architectural and artistic, constructive and engineering.
Keywords: renewable energy source, high-rise building, bioenergy, solar energy, wind energy, aerodynamics, energy-efficient technology, architectural and artistic appearance, planning solution, optimal shape of the building.aerodynamics
The article discusses the technological capabilities of application of vibratory mechanical hard lubricant coatings on the basis of MоS2 to improve the surface quality and operational properties of parts made of aluminum with an oxide coating.
Keywords: vibration treatment, the vibration mechano-chemical coating of solid lubricant, combined methods of treatment