scholarly journals EVALUATION OF THE RELIABILITY TEST RESULTS OF A ROCKET ENGINE BASED ON A LOGICAL-PROBABILISTIC METHOD

2019 ◽  
Vol 27 (4) ◽  
pp. 21-24
Author(s):  
Sergey Mikhailovich Podolchak
Keyword(s):  
Rocket Engine ◽  
Probabilistic Method ◽  
A Priori ◽  
Rocket Engines ◽  
Test Results ◽  
Reliability Models ◽  
Complex Technical Systems ◽  
Priori Information ◽  
Theory Of Evidence ◽  
The Cost

A logical-probabilistic method for evaluating the test result is proposed, which is based on the theory of evidence of Dempster-Schafer with some assumptions that do not affect the final result. Currently, there is an acute question of creating new types of rocket technology in connection with a change in the situation on the international and domestic market. When creating new samples, it is necessary to pay special attention to the level of their reliability, but also remember to take into account the financial component of projects for the development and manufacture of products. In this regard, research is currently being conducted not only in the direction of increasing the reliability of complex technical systems, which include rocket engines, but also in reducing the cost of their refinement. One of the research options in this direction was proposed by the author in this work. The aim of the work and research as a whole was to demonstrate the capabilities of the chosen method for evaluating the test results, according to which it would be possible to draw conclusions about the success of the tests themselves. As studies have shown, the logical-probabilistic method for evaluating test results based on the Dempster-Schafer theory of evidence, due to the lack of a priori information, can be used in the development of new rocket engine models, but only in a narrow direction. More widely, this method can be used in the design of products based on accumulated experience (amount of information) on existing analogues. Dempster-Schafer proof theory can be applied at earlier design stages, but only in combination with other reliability models.

Starting Transient Experiments in the MEC-80 Rocket Engine Scaled Ignition Device

2014 ◽  
Vol 656 ◽  
pp. 110-117
Author(s):  
Radu Dan Rugescu ◽  
Florin Radu Bacaran ◽  
Stefan Catalin Predoiu
Keyword(s):  
Rocket Engine ◽  
Combustion Process ◽  
Time Interval ◽  
Rocket Engines ◽  
Test Results ◽  
Transient Experiments ◽  
Design And Manufacturing ◽  
Definite Time ◽  
Solid Liquid ◽  
Ignition Device

One of the main sources of concern within the design and manufacturing of rocket engines is the starting device, due to the relatively low reliability of the ignition of the main combustion process in these engines. Not only is necessary for the igniter to produce a sound ignition, but the starting pressure transient should manifest a tightly controlled build-up, in a very definite time interval. A specific research and development work was done by the authors in order to reliably assess the requirements for the ignition device of the newly developed compound, solid-liquid experimental rocket engine MEC-80 of the ADDA team. Computer predictions and scaled experiments on the constant volume combustion into a modified calorimeter were performed with notable results that led to the optimal design of the ignition device of the motor. The test results are presented with emphasize on the predictability of the ignition delay.

scholarly journals Air delay propagation patterns in Europe from 2015 to 2018: an information processing perspective

2021 ◽  
Author(s):  
Luisina Pastorino ◽  
Massimiliano Zanin
Keyword(s):  
Information Processing ◽  
A Priori ◽  
Future Research ◽  
Negative Effects ◽  
Delay Propagation ◽  
Complementary Approach ◽  
Priori Information ◽  
The Individual ◽  
The Cost

Abstract The characterisation of delay propagation is one of the major topics of research in air transport management, due to its negative effects on the cost-efficiency, safety and environmental impact of this transportation mode. While most research works have naturally framed it as a transportation process, the successful application of network theory in neuroscience suggests a complementary approach, based on describing delay propagation as a form of information processing. This allows reconstructing propagation patterns from the dynamics of the individual elements, i.e. from the evolution observed at individual airports, without the need of additional a priori information. We here apply this framework to the analysis of delay propagation in the European airspace between 2015 and 2018, describe the evolution of the observed structure, and identify the role of individual airports in it. We further use this analysis to illustrate the limitations and challenges associated to this approach, and to sketch a roadmap of future research in this evolving topic.

COMBINED CHANNEL PROCESSING TECHNOLOGY BASED ON MULTI-LAYER TEMPLATES

2021 ◽  
pp. 89-96
Author(s):  
А.В. Щеднов ◽  
В.П. Смоленцев ◽  
Н.С. Поташникова
Keyword(s):  
Rocket Engine ◽  
High Heat ◽  
Rocket Engines ◽  
Combustion Chambers ◽  
Bottom Part ◽  
Narrow Channels ◽  
Engine Cooling ◽  
The Cost ◽  
New Generation ◽  
Combined Channel

Рассмотрена технология изготовления дополнительных элементов систем охлаждения ракетных двигателей в форме местных углублений, расположенных на имеющихся фрезерованных каналах на наружных поверхностях камер сгорания и реактивного сопла. Такая проблема требует решения в перспективных изделиях с повышенной теплонапряженностью зоны горения топлива. Проведен анализ конструкции и возможностей обработки дополнительных элементов охлаждения в донной части и на боковых поверхностях узких каналов с ограниченным доступом инструмента в зону удаления припуска. Изучены новые конструкции инструмента для комбинированной обработки с использованием шаблонов различной конструкции и обоснована возможность их использования для изготовления углублений в каналах. Предложены новые способы комбинированной локальной обработки углублений с несимметричной геометрией сечения, форма которых обоснована в процессе отработки технологичности конструкции создаваемых двигателей, что ранее считалось неосуществимым или чрезмерно трудоемким. Исследована возможность многоместной обработки локальных углублений для дополнительного охлаждения в каналах на участках с переменным профилем камер сгорания современных и перспективных изделий по многослойным шаблонам. Здесь разработанные комбинированные технологии дают наибольший эффект и способствуют повышению ресурса двигателей новых поколений до уровня, обеспечивающего многократное увеличение количества безотказных пусков космических систем, что значительно снижает затраты на изготовление ракетных двигателей новых поколений The article considers the technology of manufacturing additional elements of rocket engine cooling systems in the form of local recesses located on the existing milled channels on the outer surfaces of the combustion chambers and the jet nozzle. This problem requires solutions in promising products with high heat stress of the fuel combustion zone. We analyzed the design and processing capabilities of additional cooling elements in the bottom part and on the side surfaces of narrow channels with limited tool access to the allowance removal zone. We studied new tool designs for combined processing using templates of various designs and justified the possibility of their use for making recesses in channels. We propose new methods of combined local processing of recesses with an asymmetric cross-section geometry, the shape of which is justified in the process of testing the manufacturability of the design of the created engines, which was previously considered impossible or excessively labor-intensive. We investigated the possibility of multi-site processing of local recesses for additional cooling in channels in areas with a variable profile of the combustion chambers of modern and promising products using multilayer templates. Here, the developed combined technologies give the greatest effect and contribute to increasing the resource of new-generation engines to a level that provides a multiple increase in the number of trouble-free launches of space systems. This significantly reduces the cost of manufacturing new-generation rocket engines

scholarly journals Simple Market Equilibria with Rationally Inattentive Consumers

2012 ◽  
Vol 102 (3) ◽  
pp. 24-29 ◽  
Author(s):  
Filip Matějka ◽  
Alisdair McKay
Keyword(s):  
A Priori ◽  
A Priori Information ◽  
Symmetric Equilibrium ◽  
Priori Information ◽  
The Cost ◽  
Market Equilibria ◽  
Number Of Firms

We study a market with rationally inattentive consumers who are unsure of the terms of the offers made by firms, but can acquire information about the terms at a cost. In a symmetric equilibrium, the price set by firms is continuously increasing in the cost of information for consumers and decreasing in the number of firms operating. In addition, favorable a priori information about a firm leads it to set a higher price, and a new entrant can increase demand for incumbents. When consumers have heterogeneous costs of information, firms selling low-quality products may choose to set the highest prices.

scholarly journals Regularization of the problems of planning and processing the test results of pipeline systems for hydraulic losses

2018 ◽  
Vol 212 ◽  
pp. 01006
Author(s):  
Oksana Grebneva
Keyword(s):  
Computer Modelling ◽  
A Priori ◽  
Identification Problem ◽  
Test Results ◽  
Initial Information ◽  
Active Experiments ◽  
Priori Information ◽  
Parameter Values ◽  
Modelling Methods ◽  
Independent Parameters

The lack of reliable information on actual characteristics and parameters is the main deterrent to the effective application of mathematical and computer modelling methods for solving problems of optimal reconstruction, adjustment, and development of operational problems. The lack of such information is solved on the basis of applying the identification problems that require expert (approximate) specification of a priori parameter values. This leads to the sensitivity of the solution of identifying a problem to the errors in setting the initial information. One way to solve this problem is to apply regularization methods. In this paper, a numerical example proposes a rule for expert assignment of a priori information on the parameters of elements, which makes it possible to minimize its influence on the results of planning active experiments. In addition, the paper shows the independence of the solution of the identification problem from the composition of the vector of independent parameters.

scholarly journals ОЦІНКА НАДІЙНОСТІ РАКЕТНОГО ДВИГУНА ЯК СКЛАДНОЇ ТЕХНІЧНОЇ СИСТЕМИ ЗА НЕДОСТАТНЬОЇ СТАТИСТИЧНОЇ ІНФОРМАЦІЇ

2018 ◽  
pp. 36-43
Author(s):  
Володимир Олексійович Габрінець ◽  
Сергій Михайлович Подольчак
Keyword(s):  
Early Stage ◽  
Rocket Engine ◽  
A Priori ◽  
Statistical Information ◽  
Technical System ◽  
Sufficient Information ◽  
A Priori Information ◽  
Complex Technical System ◽  
Tolerance Field ◽  
Priori Information

The subject matter of the article is an analysis of methods for assessing the reliability of a complex technical system applicable to a rocket engine for solving the problem of estimating the reliability of a rocket engine at an early stage of its development. The goal is to determine the method of estimating the reliability of a rocket engine with insufficient statistical information. The tasks to be solved: to carry out the analysis of existing methods for assessing the reliability of a complex technical system; to justify the expediency of their application for assessing the reliability of the rocket engine at an early stage of its development; choose an effective method for solving the problem. In work the analysis of following methods was carried out: a method of rationing reliability taking into account the complexity of the system and the importance of the elements belonging to the system; method of "weighting factors"; method of accounting for a priori information when using the model "parameter – one-way tolerance field". The following results obtained during the research. As a result of the analysis of existing methods for assessing the reliability of a complex technical system, it argues that they can apply to a rocket engine in terms of the availability of sufficient information When determining the method for estimating the reliability of a rocket engine with insufficient statistical information, a reliability chosen model that allows estimating the level of reliability of a rocket engine at an early stage of its development with insufficient information.  Conclusions. The scientific novelty of the results is following: the proposed method makes it possible to assess the level of reliability of rocket engines of new developments when the designers do not have sufficient statistical information on the results of reliability tests, that is, at the very beginning of the development of the rocket engine; developed methods for assessing reliability of a complex technical system applied to a rocket engine with the use of the "parameter – one-way tolerance field" model was further developed, thanks to the availability of a priori information, which makes it possible to use them for various approaches to assess the reliability of a rocket engine, depending on the amount of information available

scholarly journals A modified generalized residual method for minimization problems with errors of a known level in weakened norms

2015 ◽  
pp. 456-463
Author(s):  
А.А. Дряженков
Keyword(s):  
A Priori ◽  
A Priori Information ◽  
Error Level ◽  
Numerical Examples ◽  
Residual Method ◽  
Quadratic Minimization ◽  
Minimization Problems ◽  
Priori Information ◽  
The Cost ◽  
Nonclassical Information

Предложен алгоритм численного решения задачи квадратичной минимизации на эллипсоиде, заданном в гильбертовом пространстве компактным оператором. Алгоритм представляет собой определенную трансформацию обобщенного метода невязки, предназначенную для применения в неклассических информационных условиях, когда априорная информация об уровне погрешности в операторе, задающем функционал, доступна лишь в нормах, ослабленных по сравнению с исходными. При этом сходимость алгоритма устанавливается в исходных нормах. Приводятся простейшие вычислительные иллюстрации. An algorithm is proposed for the numerical solution of a quadratic minimization problem on an ellipsoid specified in the Hilbert space by a compact operator. This algorithm is a certain transform of the generalized residual method designed previously for the application in nonclassical information conditions when {\it a priori} information on the error level in an operator defining the cost functional is available only in the norms being weaker than the original ones. At the same time, the convergence of the algorithm is proved in the original norms. A number of simple numerical examples are discussed.

Curve Fitting and Deconvolution of Instrumental Broadening: A Simulated Annealing Approach

1995 ◽  
Vol 49 (3) ◽  
pp. 273-278 ◽  
Author(s):  
A. Ferry ◽  
P. Jacobsson
Keyword(s):  
Simulated Annealing ◽  
Curve Fitting ◽  
Simulated Annealing Algorithm ◽  
A Priori ◽  
Global Optimum ◽  
Fitting Procedure ◽  
Instrumental Resolution ◽  
Priori Information ◽  
Definition Of ◽  
The Cost

A curve-fitting procedure based on the simulated annealing algorithm has been developed for the analysis of spectral Raman data. By the inclusion of a priori information about the instrumental broadening in the definition of the cost function that is minimized, effects of the finite instrumental resolution are eliminated from the resulting fit. The ability of the method to reproduce original band shapes is tested on synthesized spectra and FT-Raman spectra of diamond recorded at different resolutions with different apodization functions. The procedure yields the global optimum of the fitted parameters and is easily implemented on a personal computer.

Innovative Approach to Information Search by Example of a Patent Analysis of an Important Substitution Plan

2020 ◽  
pp. 143-157
Author(s):  
Maria A. Milkova
Keyword(s):  
Information Search ◽  
Topic Modeling ◽  
Cognitive Biases ◽  
A Priori ◽  
Import Substitution ◽  
Innovative Approach ◽  
Iterative Search ◽  
Comprehensive Picture ◽  
Priori Information ◽  
Selection Of

Nowadays the process of information accumulation is so rapid that the concept of the usual iterative search requires revision. Being in the world of oversaturated information in order to comprehensively cover and analyze the problem under study, it is necessary to make high demands on the search methods. An innovative approach to search should flexibly take into account the large amount of already accumulated knowledge and a priori requirements for results. The results, in turn, should immediately provide a roadmap of the direction being studied with the possibility of as much detail as possible. The approach to search based on topic modeling, the so-called topic search, allows you to take into account all these requirements and thereby streamline the nature of working with information, increase the efficiency of knowledge production, avoid cognitive biases in the perception of information, which is important both on micro and macro level. In order to demonstrate an example of applying topic search, the article considers the task of analyzing an import substitution program based on patent data. The program includes plans for 22 industries and contains more than 1,500 products and technologies for the proposed import substitution. The use of patent search based on topic modeling allows to search immediately by the blocks of a priori information – terms of industrial plans for import substitution and at the output get a selection of relevant documents for each of the industries. This approach allows not only to provide a comprehensive picture of the effectiveness of the program as a whole, but also to visually obtain more detailed information about which groups of products and technologies have been patented.

Sign in / Sign up

Export Citation Format

Share Document