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.

Alternative Strategies for Selling Land to the Highest Bidder

1988 ◽  
Vol 20 (6) ◽  
pp. 817-828 ◽  
Author(s):  
P A Rogerson
Keyword(s):  
Waiting Times ◽  
A Priori ◽  
Complete Information ◽  
A Priori Information ◽  
Rank Minimization ◽  
Alternative Strategies ◽  
Bidding Behavior ◽  
Initial Information ◽  
Sequential Bidding ◽  
Priori Information

In this paper the properties of several models of sequential bidding behavior are evaluated. In particular, the returns to a seller who maximizes the probability of selling to the highest bidder are compared with the returns of a rank minimization strategy which is more conservative. The comparison reveals that the rank minimization strategy will generally lead to shorter waiting times, higher expected selling prices, and lower probabilities of receiving the worst bids. Both of these objectives assume that sellers have no initial information pertaining to the distribution of bid prices. This is in sharp contrast to the more usual assumption of complete information about the parameters of the distribution. The losses associated with not having a priori information on the number of bidders are also evaluated. Under such circumstances, sellers may adopt more conservative strategies, with the consequent result of shorter waiting times and lower expected prices.

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.

Identification and Control of Multidimensional Delayed Processes in Conditions of Incomplete Information

2021 ◽  
Vol 27 (12) ◽  
pp. 658-667
Author(s):  
A. V. Medvedev ◽  
◽  
D. I. Yareshchenko ◽  
Keyword(s):  
Incomplete Information ◽  
A Priori ◽  
Identification Problem ◽  
Control Algorithms ◽  
Main Task ◽  
Multidimensional System ◽  
Implicit Equations ◽  
Priori Information ◽  
Definition Of ◽  
And Control

Problems of identification and control of multidimensional discrete-continuous processes with delay in conditions of incomplete information about the object are considered. In such conditions, the form of parametric equations for various channels of the object is absent due to the lack of a priori information. Moreover, multidimensional processes have stochastic dependences of the components of the vector of output variables. Under such conditions, the mathematical description of such processes leads to a system of implicit equations. Nonparametric identification and control algorithms for multidimensional systems are proposed. The main task of modeling such processes is to determine the predicted values of the output variables from the known input. Moreover, for implicit equations, it is only known that one or another output variable can depend on other input and output variables that determine the state of a multidimensional system. In this study, a nontrivial situation arises when solving a system of implicit equations under conditions when the dependences between the components of the output variables are unknown. The application of the parametric theory of identification in this case will not lead to success. One of the possible directions is the use of the theory of nonparametric systems. The main content of the work is the solution of the identification problem in the presence of dependencies of the output variables and then the solution of the control problem for such a process. Here you should pay attention to the fact that when determining the reference actions for a multidimensional system, it is first necessary to solve the system of reference actions, since it is not possible to choose arbitrarily setting influences from the range of definition of output variables. Computational eXperiments aimed at investigating the effectiveness of the proposed identification and control algorithms are presented.

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.

scholarly journals Computational Method for Wavefront Sensing Based on Transport-Of-Intensity Equation

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 177
Author(s):  
Iliya Gritsenko ◽  
Michael Kovalev ◽  
George Krasin ◽  
Matvey Konoplyov ◽  
Nikita Stsepuro
Keyword(s):  
A Priori ◽  
Spherical Wave ◽  
Computational Method ◽  
Optical Systems ◽  
Radius Of Curvature ◽  
Imaging Method ◽  
Wavefront Sensing ◽  
Phase Imaging ◽  
Transport Of Intensity Equation ◽  
Priori Information

Recently the transport-of-intensity equation as a phase imaging method turned out as an effective microscopy method that does not require the use of high-resolution optical systems and a priori information about the object. In this paper we propose a mathematical model that adapts the transport-of-intensity equation for the purpose of wavefront sensing of the given light wave. The analysis of the influence of the longitudinal displacement z and the step between intensity distributions measurements on the error in determining the wavefront radius of curvature of a spherical wave is carried out. The proposed method is compared with the traditional Shack–Hartmann method and the method based on computer-generated Fourier holograms. Numerical simulation showed that the proposed method allows measurement of the wavefront radius of curvature with radius of 40 mm and with accuracy of ~200 μm.

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