Browsing by Author "Kravets, Vladimir V."
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Item Mathematical Model of a Path and Hodograpf of Surface Transport(Katowice, Poland, 2014) Kravets, Vladimir V.; Kravets, Tamila V.; Bas, Kostyantyn M.; Tokar, Larisa A.ENG: With the increase in speed of wheeled vehicles, such lead nations follow their research on determining new forms of transit curves. Transit curves proposed from the viewpoint of heuristic or criteria ideas should meet true guide path of transport vehicle at both constant and alternative speed. It is proposed to form a plan, longitudinal and cross-sectional profile of highways in junctions and turns in the form of ruled surface (Shukhov’s surface) which components are in anormal plane of true trihedr on of motion path and guide path selected as a part of spiral line covering nine variable parameters determined on required boundary conditionals imposed on the curve value too if motion models are specified. It is set as specified both location and speed of a vehicle during input/output moments within considered curved highway area. It is required to determine hodograph corresponding specified mode of the vehicle movement along the highway considered as a motion trajectory. Hodograph of vehicle movement dependingupon various modes – accelerated, decelerated, with constant speed, injunctions and turns, within straight and curved areas, while sloping and rising can be synthesized in a class of proposed spiral lines (guidepaths) corresponding to true, undisturbed trajectories of a vehicle.Item Matrix Method for Determining Structural Reliability of the System and Significance of Its Elements in Terms of Reliability(Scientific Research Publishing, 2015) Kravets, Viktor V.; Kravets, Vladimir V.; Burov, OlexiyEN: Matrix method is being proposed for qualitative evaluation of the reliability of technical systems on a finite set of structural elements. We are introducing the criteria for qualitative assessment of the reliability in the form of structural reliability of the system as the probability of the troubleproof state of this system and the significancy of the individual elements in ensuring the structural reliability of the system as a general aggregate of conditional probabilities, which compose two (2×2) matrices of significancy for each element. We are using chain diagrams for solving the combinatronic problems and matrices for algorithmization of calculating procedures.Item Modelling of Wound Process Dynamics in Patients with Diabetes Mellitus In Addition to VAC-Therapy with a Discrete-Time Markov Chain(Scholars Academic and Scientific Publisher, India, 2015) Kravets, Viktor V.; Besedin, Alexander M.; Kravets, Vladimir V.EN: The wound process in patients with diabetes mellitus in addition to VAC-therapy (Vacuum-assisted closure — VAC® therapy) is examined. The model of the biological system describing the wound process is built on three independently functioning subsystems; it is assumed to be ergodic and presented with a symmetric graph. The mathematical model of the wound process dynamics is constructed based on a discrete-time Markov chain and constitutes an eighth-order iterative matrix equation. A period of 24 hours is taken as the discrete time during which the probabilistic characteristics of the subsystems are assumed to be averaged. The phase course of the wound process in patients with diabetes mellitus in addition to VAC-therapy is viewed as a Markovian process of the biological system random walk among eight possible states depending on the preassigned baseline state and transition probabilities. It is tested for stability. The calculation algorithms modelling multidimensional Markovian processes are adapted to computer technology.Item On Application of the Ground Effect for Highspeed Surface Vehicles(Magnolithe GmbH, Sankt Lorenzen, Austria, 2016) Kravets, Viktor V.; Kravets, Vladimir V.; Fedoriachenko, S. A.EN: The paper describes a new approach for driving efficiency estimation. Authors proposed a new approach to assess the energy consumption for vehicle, which are able to rich high speed. Also, there is proposed a new concept of vehicle, which technology based on the ground effect. The concept compounds the automotive and aircraft’s solutions in order to reach high driving speed, driving efficiency and low energy consumption per cargo unit. As a result, the defined performance indicators for the transport systems opens up the possibility to formulate and solve optimization problems of structural and parametric synthesis of new types of transport, provide the analytical tools to make informed decisions in the process of design and construction, provide an overall controlled evolution of transport systems.Item Program Spatial Movement of High-Speed Vehicles(IOP Publishing, 2018) Kravets, Viktor V.; Sakhno, V.; Bas, Kostyantyn M.; Kravets, Vladimir V.EN: Program spatial movement of a high-speed vehicle has been synthesized with thehelp of hodograph in terms of spiral paths. A mathematical model of a primary road in the form of a line over ruled bearing surface in the neighbourhood of the program trajectory has been developed. Vector equations of the elements of ruled surface and bearing surfaces oriented orthogonally to inertia forces have been set up. The inertia forces effecting a mass of a highspeed vehicle in the context of non-uniform motion along spiral program path has been demonstrated in a vector form.Item Reliability of Systems. Part 1. Statics of Failures(LAP LAMBERT Academic Publishing, Saarbrucken, Germany, 2016) Kravets, Viktor V.; Kravets, Vladimir V.; Burov, OlexiyEN: We consider in-depth mechanical, geometric, analytic models of assessment the reliability of systems based on the use of the scheme of cases, Euler-Venn diagrams, generating functions, state diagrams. The methods of qualitative and quantitative assessment of the reliability on the established time interval, based on structural reliability, the importance of a structural element, the sensitivity of the reliability of the system taking into account the duplication of most significant and unreliable elements. Common approaches are illustrated by solving problems of the analysis and synthesis of reliable systems. This book is recommended for engineers, teachers and students of high educational institutions, who in their practice pose and solve problems of reliability of technical systems. The book contains a number of new materials developed by the authors in the last years that have not been published before.Item Reliability of Systems. Part 2. Dynamics of Failures(LAP LAMBERT Academic Publishing, Saarbrucken, Germany, 2016) Kravets, Viktor V.; Kravets, Vladimir V.; Burov, OlexiyEN: The “Reliability of Systems. Dynamics of failures” covers the basic provisions of systems reliability assessment in dynamic run-time. A symmetrical structure discrete Markov chains are being considered for modeling random processes, such as failures and recoveries in technical and biological systems. The criterion of stability of random Markov process was established. An algorithm for determining the marginal probabilities of system states was developed. A method for evaluating the economic efficiency of the simulated discrete Markov chains was proposed. The matrix of transition prices was introduced, the appropriate mathematical conversions price expectations and the expectation of price transition system throughout possible states. The method is illustrated on the biological system and the Smart house system. This book is recommended for engineers, teachers and students of high education institutions, who in their practice pose and solve problems of reliability of systems. The book contains a number of new materials developed be the authors in the last years that have not been published before in full.Item The Vehicle Controlling Near the Screening Surface Using Thrust Vector Deflection of the Electric Motor with Gimbal Mounted Propeller(Magnolithe GmbH, Sankt Lorenzen, 2017) Kravets, Viktor V.; Kravets, Vladimir V.; Artemchuk, Viktor V.EN: The controlled spatial motion of the combined vehicle near the screening surface is considered. A propeller motor in a gimbal mount forms control forces and moments. The gimbal mount scheme can be defined on a finite set of successive three independent turns with recurrence, which is represented by 96 variants. The constructive scheme of the gimbal mount of propeller electric motor is proposed, which provides control of combined vehicle in the three main modes: Lifting force (helicopter scheme); Traction mode (aircraft scheme); Lateral traction (course control). The rotative axis of the propeller is combined in coincidence with rotor axis of electric motor determining the first turning of the gimbal mount. The electric motor’s stator is located on the inner ring of the gimbal and its rotation axis determines the second finite turn. The turning axis of the outer race of the gimbal relatively the case of the combined vehicle defines the third finite turning movement. This constructive solving of the gimbal mount provides the combined control of thrust vector in wide range of finite turning angles. Basis of movable Cartesian coordinate system is coincides with the rotation axes intersection point. For the entered reference systems and the accepted sequence of finite independent turning movements matrixes of the forward and inverse transform of coordinates in the form of quaternion matrixes are formed. In the form of quaternion matrices, depending on the angle of the thrust vector and the arrangement of the gimbal mount, the driving forces and moments in the reference frame that is associated with the vehicle are determined.