AN ELECTROMAGNETIC CATAPULT FOR LAUNCHING HEAVY UAVs (DRONES) FROM SMALL VESSELS

2021 ◽  
pp. 25-34
Author(s):  
A.P. Baganov ◽  
◽  
V.G. Butov ◽  
G.V. Nosov ◽  
M.G. Nosova ◽  
...  
Keyword(s):  
Maximum Acceleration ◽  
Idle Mode ◽  
Small Vessels ◽  
Mhd Generator ◽  
Electromechanical Energy Conversion ◽  
Proposed Model ◽  
Rail Accelerator ◽  
Electromechanical Energy ◽  
The Moment ◽  
The Mathematical Model

The paper presents the results of mathematical modeling of the operation of a novel electromagnetic catapult design. The main elements of the latter are a single-section multi-rail accelerator with a metal armature and a pulsed energy source based on the powerful pulsed MHD generator and current-increasing transformer. The possibilities of such a scheme for accelerating bodies weighing 7 tons to speeds of about 150 km/h at a maximum permissible acceleration of 15 g are investigated. The mathematical model describes the coordinated operation of the device, starting with connecting of the pulsed MHD generator in idle mode to the primary winding of the transformer and up to the moment when the drone accelerates to a given takeoff speed. Using the proposed model, the efficiency of the electromechanical energy conversion in the developed catapult scheme is tested. The parameters of the main elements of the device, namely the length of the acceleration section of the catapult and the maximum acceleration of the drone, are determined.

THE DEVELOPMENT OF THE MATHEMATICAL MODEL OF PREDICTING THE INDICATORS OF ACCREDITATION OF TECHNICAL UNIVERSITIES IN THE RUSSIAN FEDERATION

2017 ◽  
pp. 27-38
Author(s):  
Olga Mikhaylovna Tikhonova ◽  
Alexander Fedorovich Rezchikov ◽  
Vladimir Andreevich Ivashchenko ◽  
Vadim Alekseevich Kushnikov
Keyword(s):  
Mathematical Model ◽  
System Dynamics ◽  
Regression Model ◽  
Oriented Graph ◽  
Real Data ◽  
Educational Process ◽  
Proposed Model ◽  
Linear Differential ◽  
The University ◽  
The Mathematical Model

The paper presents the system of predicting the indicators of accreditation of technical universities based on J. Forrester mechanism of system dynamics. According to analysis of cause-and-effect relationships between selected variables of the system (indicators of accreditation of the university) there was built the oriented graph. The complex of mathematical models developed to control the quality of training engineers in Russian higher educational institutions is based on this graph. The article presents an algorithm for constructing a model using one of the simulated variables as an example. The model is a system of non-linear differential equations, the modelling characteristics of the educational process being determined according to the solution of this system. The proposed algorithm for calculating these indicators is based on the system dynamics model and the regression model. The mathematical model is constructed on the basis of the model of system dynamics, which is further tested for compliance with real data using the regression model. The regression model is built on the available statistical data accumulated during the period of the university's work. The proposed approach is aimed at solving complex problems of managing the educational process in universities. The structure of the proposed model repeats the structure of cause-effect relationships in the system, and also provides the person responsible for managing quality control with the ability to quickly and adequately assess the performance of the system.

MULTISTAGE ROCKET FLIGHT SIMULATION

2019 ◽  
pp. 105-107
Author(s):  
A. S. Busygin ◽  
А. V. Shumov
Keyword(s):  
State Vector ◽  
Center Of Mass ◽  
Flight Simulation ◽  
Continuous Change ◽  
Information Tools ◽  
The Earth ◽  
Proposed Model ◽  
Piecewise Continuous ◽  
The Moment ◽  
Simulated Object

The paper considers a method for simulating the flight of a multistage rocket in Matlab using Simulink software for control and guidance. The model takes into account the anisotropy of the gravity of the Earth, changes in the pressure and density of the atmosphere, piecewise continuous change of the center of mass and the moment of inertia of the rocket during the flight. Also, the proposed model allows you to work out various targeting options using both onboard and ground‑based information tools, to load information from the ground‑based radar, with imitation of «non‑ideality» of incoming target designations as a result of changes in the accuracy of determining coordinates and speeds, as well as signal fluctuations. It is stipulated that the design is variable not only by the number of steps, but also by their types. The calculations are implemented in a matrix form, which allows parallel operations in each step of processing a multidimensional state vector of the simulated object.

scholarly journals On the Dragging Trajectory of Anchors in Clay for Merchant Ships

2021 ◽  
Vol 9 (2) ◽  
pp. 118
Author(s):  
Xinqing Zhuang ◽  
Keliang Yan ◽  
Pan Gao ◽  
Yihua Liu
Keyword(s):  
Mathematical Model ◽  
Structural Integrity ◽  
Indirect Measurement ◽  
Test System ◽  
Flow Rule ◽  
Burial Depth ◽  
Proposed Model ◽  
Depth Increase ◽  
Two Parameters ◽  
The Mathematical Model

Anchor dragging is a major threat to the structural integrity of submarine pipelines. A mathematical model in which the mechanical model of chain and the bearing model of anchor were coupled together. Based on the associated flow rule, an incremental procedure was proposed to solve the spatial state of anchor until it reaches the ultimate embedding depth. With an indirect measurement method for the anchor trajectory, a model test system was established. The mathematical model was validated against some model tests, and the effects of two parameters were studied. It was found that both the ultimate embedding depth of a dragging anchor and the distance it takes to reach the ultimate depth increase with the shank-fluke pivot angle, but decrease as the undrained shear strength of clay increases. The proposed model is supposed to be useful for the embedding depth calculation and guiding the design of the pipeline burial depth.

scholarly journals Content Dependent Representation Selection Model for Systems Based on MPEG DASH

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1843
Author(s):  
Jelena Vlaović ◽  
Snježana Rimac-Drlje ◽  
Drago Žagar
Keyword(s):  
Mathematical Model ◽  
Spatial Information ◽  
Relevant Literature ◽  
Video Quality ◽  
Similarity Index ◽  
Video Encoding ◽  
Adaptation Algorithm ◽  
Subjective Testing ◽  
Proposed Model ◽  
The Mathematical Model

A standard called MPEG Dynamic Adaptive Streaming over HTTP (MPEG DASH) ensures the interoperability between different streaming services and the highest possible video quality in changing network conditions. The solutions described in the available literature that focus on video segmentation are mostly proprietary, use a high amount of computational power, lack the methodology, model notation, information needed for reproduction, or do not consider the spatial and temporal activity of video sequences. This paper presents a new model for selecting optimal parameters and number of representations for video encoding and segmentation, based on a measure of the spatial and temporal activity of the video content. The model was developed for the H.264 encoder, using Structural Similarity Index Measure (SSIM) objective metrics as well as Spatial Information (SI) and Temporal Information (TI) as measures of video spatial and temporal activity. The methodology that we used to develop the mathematical model is also presented in detail so that it can be applied to adapt the mathematical model to another type of an encoder or a set of encoding parameters. The efficiency of the segmentation made by the proposed model was tested using the Basic Adaptation algorithm (BAA) and Segment Aware Rate Adaptation (SARA) algorithm as well as two different network scenarios. In comparison to the segmentation available in the relevant literature, the segmentation based on the proposed model obtains better SSIM values in 92% of cases and subjective testing showed that it achieves better results in 83.3% of cases.

scholarly journals An Optimized Mathematical Model for Items Supplies Planning of a Logistic System

2016 ◽  
Vol 10 (10) ◽  
pp. 133
Author(s):  
Mohammad Ali Nasiri Khalili ◽  
Mostafa Kafaei Razavi ◽  
Morteza Kafaee Razavi
Keyword(s):  
Mathematical Model ◽  
Mixed Integer ◽  
Logistics System ◽  
Proposed Model ◽  
Multiple Objective Decision Making ◽  
System Requirements ◽  
Purchasing Logistics ◽  
The Cost ◽  
The Mathematical Model ◽  
First Time

Items supplies planning of a logistic system is one of the major issue in operations research. In this article the aim is to determine how much of each item per month from each supplier logistics system requirements must be provided. To do this, a novel multi objective mixed integer programming mathematical model is offered for the first time. Since in logistics system, delivery on time is very important, the first objective is minimization of time in delivery on time costs (including lack and maintenance costs) and the cost of purchasing logistics system. The second objective function is minimization of the transportation supplier costs. Solving the mathematical model shows how to use the Multiple Objective Decision Making (MODM) can provide the ensuring policy and transportation logistics needed items. This model is solved with CPLEX and computational results show the effectiveness of the proposed model.

Methods of Mathematical Modeling of the Leaching Process of Cobalt-Containing Solutions

2021 ◽  
Vol 316 ◽  
pp. 661-666
Author(s):  
Nataliya V. Mokrova
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Chemical Kinetics ◽  
Group Method ◽  
Data Handling ◽  
Multistage Processes ◽  
Leaching Process ◽  
Proposed Model ◽  
Simulation Results ◽  
The Mathematical Model

Current cobalt processing practices are described. This article discusses the advantages of the group argument accounting method for mathematical modeling of the leaching process of cobalt solutions. Identification of the mathematical model of the cascade of reactors of cobalt-producing is presented. Group method of data handling is allowing: to eliminate the need to calculate quantities of chemical kinetics; to get the opportunity to take into account the results of mixed experiments; to exclude the influence of random interference on the simulation results. The proposed model confirms the capabilities of the group method of data handling for describing multistage processes.

Convergence–confinement analysis of a bolt-supported tunnel using the homogenization method

2006 ◽  
Vol 43 (5) ◽  
pp. 462-483 ◽  
Author(s):  
Henry Wong ◽  
Didier Subrin ◽  
Daniel Dias
Keyword(s):  
Input Parameter ◽  
Uniaxial Stress ◽  
Homogenization Method ◽  
External Input ◽  
Proposed Model ◽  
Homogenization Approach ◽  
Parametric Studies ◽  
Perfect Bonding ◽  
The Moment ◽  
Grouted Bolts

The behaviour of tunnels reinforced with radially disposed fully grouted bolts is investigated in this paper. Perfect bonding and ideal diffusion of bolt tension are assumed, so that the bolt tension can be assimilated to an equivalent uniaxial stress tensor. An analytical model of the convergence–confinement type is proposed that accounts for the delayed action of bolts due to ground decompression prior to bolt installation. This factor leads to nonsimultaneous yielding, and more generally, a different stress history for each constituent, requiring special treatments in the incremental elastoplasticity calculations. Nonetheless, the resulting model remains sufficiently simple, and an analytical solution is still accessible. Charts are provided to allow for parametric studies and quick preliminary designs. Comparisons with 3D numerical calculations show that the model gives precise results if the correct convergence at the moment of bolt installation is used as an "external" input parameter, validating the homogenization approach. An approximate methodology based on previous works is proposed to determine this parameter to render the proposed model "self-sufficient." Its predictions are again compared to 3D numerical computations, and the results are found to be sufficiently accurate for practical applications.Key words: reinforcement, anisotropy, analytical, lining, yield, elastoplasticity.

scholarly journals NEW WAYS OF PACKAGE PROJECTS FOR SMALL AND MEDIUM-SIZED ENTERPRISES (SME) IN GERMANY/NEUE WEGE IM SCHLÜSSELFERTIGBAU FÜR KLEINE UND MITTELSTÄNDISCHE UNTERNEHMEN

2001 ◽  
Vol 7 (4) ◽  
pp. 294-303
Author(s):  
Bernd Reichelt
Keyword(s):  
Public Relations ◽  
Integrated System ◽  
Software Test ◽  
Software Support ◽  
Business Units ◽  
Proposed Model ◽  
New Ideas ◽  
Good Potential ◽  
The Moment ◽  
Support Software

In Germany the building industry is in recession at the moment. Especially the SMEs have to adapt to different situation in order to survive. One possible strategy could be taken on orders as main contractors. This has until now been donne dominantely by large building enterprises. The author describes problems and chances which arise if the SMEs take on package projects. He develops a strategic idea that is based on intensive use of computers in all processes and on new forms of cooperation (partnering) that is less known in Germany. The author is convinced that in future the collaboration of partners will play a significant role in the construction of structures that are completely finished and ready for sale. After the improvement of the prototype and optimisation of the information system, the proposed model has a good potential in the field of small and medium business units. After the methodological knowledge and software blend into one product, a new solution will be received, viz the franchise. The integrated system of working with an interested contractor general, his subcontractors and, if necessary, the construction master, that includes training, software support, software test runs, elimination of conflicts and faults, etc. In the first projects the franchiser must provide the intermediator. The Institute of Collaboration of Construction Partners that earns its income from the sale of franchises may perform scientific improvement of methods and software; the Institute is also engaged in dealing with atypical problems, support of subcontractors and contractors in their search for new ideas, as well as in the promotion of its methods using public relations.

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