Wyniki wyszukiwania - BazTech

1

The importance of structural and practical unidentifiability in modeling and testing of agricultural machinery. Identifiability testing of aggregate model parameters tractor-baler wrapper

Kromulski Jacek, Szczepaniak Jan, Mac Jarosław, Wojciechowski Jacek, Zawada Michał, Szulc Tomasz, Rogacki Roman, Jakubowski Łukasz, Aleksandrowicz Roman

Journal of Research and Applications in Agricultural Engineering

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2021

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Vol. 66, nr 1

4--9

EN

New methods of parametric identification are presented in particular tests of identifiability and non-identifiability of model parameters. A definition of the concept of identifiability of model parameters is presented. Methods for testing identifiability using Laplace transform using similarity transformation and using symbolic calculations are described. Available software for testing model identifiability is presented. These are programs for symbolic calculations (MAPLE MATHEMATICA) operating in the form of web applications and in the form of tools for the Matlab environment. The method of introducing the model to the computational environment in the form ordinary differential equations (ODE) is presented. Examples of calculations identifiability of parameters of the complex model of the tractor-single-axle agricultural machine e.g. a balerwrapper are included.

PL

Przedstawiono nowe metody prowadzenia identyfikacji parametrycznej w szczególności badania identyfikowalności oraz nieidentyfikowalności parametrów modelu. Przedstawiono definicję pojęcia identyfikowalności parametrów modelu. Opisano metody badania identyfikowalności za pomocą transformacji Laplace'a z zastosowaniem transformacji podobieństwa oraz za pomocą obliczeń symbolicznych. Przedstawiono dostępne oprogramowanie do badania identyfikowalności modelu. Są to programy do obliczeń symbolicznych (MAPLE MATHEMATICA) działające w formie aplikacji sieciowych oraz w postaci przyborników do środowiska Matlab. Przedstawiono sposób wprowadzenia modelu do środowiska obliczeniowego w postaci równań różniczkowych zwyczajnych. Zamieszczono przykładowe wyniki obliczeń identyfikowalności parametrów złożonego modelu układu ciągnik-jednoosiowa maszyna rolnicza, np. prasoowijarka.

2

Illustrative presentation of some basic concepts of network internal reliability with comments as regards engineering surveys

Prószyński W.

Reports on Geodesy and Geoinformatics

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2016

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Vol. 101

54--59

EN

The paper integrates some earlier and the recent findings of the author in the area of network internal reliability and presents a consistent system of concepts in this respect. The concepts of outlier detection and outlier identification linked directly with the global model test and the outlier tests respectively, are shown as a basis for the concepts such as outlier detectability and outlier identifiability. Also, a four level classification of gross errors expressed in a form of a tree-diagram is presented including perceptible and imperceptible errors, detectable and undetectable errors and identifiable and unidentifiable errors. Their properties are given mainly in a descriptive way, deliberately limiting rigorous mathematical formulas to a necessary minimum. Understanding of different types of gross errors is useful in analyzing the results of the outlier detection and identification procedures as well as in designing the networks to make them duly robust to observation gross errors. It is of special importance for engineering surveys where quite often low-redundancy networks are used. Main objective of the paper is to demonstrate a clear and consistent system of basic concepts related to network internal reliability.

3

Set-membership identifiability of nonlinear models and related parameter estimation properties

Jauberthie C., Travé-Massuyès L., Verdière N.

International Journal of Applied Mathematics and Computer Science

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2016

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Vol. 26, no. 4

803--813

EN

Identifiability guarantees that the mathematical model of a dynamic system is well defined in the sense that it maps unambiguously its parameters to the output trajectories. This paper casts identifiability in a set-membership (SM) framework and relates recently introduced properties, namely, SM-identifiability, μ-SM-identifiability, and ε-SM-identifiability, to the properties of parameter estimation problems. Soundness and ε-consistency are proposed to characterize these problems and the solution returned by the algorithm used to solve them. This paper also contributes by carefully motivating and comparing SM-identifiability, μ-SM-identifiability and ε-SM-identifiability with related properties found in the literature, and by providing a method based on differential algebra to check these properties.

4

An attempt to determine the effect of increase of observation correlations on detectability and identifiability of a single gross error

Prószyński W., Kwaśniak M.

Geodesy and Cartography

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2016

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Vol. 65, no. 2

313--333

EN

The paper presents the results of investigating the effect of increase of observation correlations on detectability and identifiability of a single gross error, the outlier test sensitivity and also the response-based measures of internal reliability of networks. To reduce in a research a practically incomputable number of possible test options when considering all the non-diagonal elements of the correlation matrix as variables, its simplest representation was used being a matrix with all non-diagonal elements of equal values, termed uniform correlation. By raising the common correlation value incrementally, a sequence of matrix configurations could be obtained corresponding to the increasing level of observation correlations. For each of the measures characterizing the above mentioned features of network reliability the effect is presented in a diagram form as a function of the increasing level of observation correlations. The influence of observation correlations on sensitivity of the w-test for correlated observations (Förstner 1983, Teunissen 2006) is investigated in comparison with the original Baarda’s w-test designated for uncorrelated observations, to determine the character of expected sensitivity degradation of the latter when used for correlated observations. The correlation effects obtained for different reliability measures exhibit mutual consistency in a satisfactory extent. As a by-product of the analyses, a simple formula valid for any arbitrary correlation matrix is proposed for transforming the Baarda’s w-test statistics into the w-test statistics for correlated observations.

5

Source localization and sensor placement in environmental monitoring

Khapalov A.

International Journal of Applied Mathematics and Computer Science

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2010

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Vol. 20, no 3

445-458

EN

In this paper we discuss two closely related problems arising in environmental monitoring. The first is the source localization problem linked to the question How can one find an unknown 'contamination source'? The second is an associated sensor placement problem: Where should we place sensors that are capable of providing the necessary 'adequate data' for that? Our approach is based on some concepts and ideas developed in mathematical control theory of partial differential equations.

6

Identification and identifiability of models of cell signalling pathways

Fujarewicz K., Kimmel M., Świerniak A.

Przegląd Elektrotechniczny

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2008

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R. 84, nr 5

91-94

EN

The dynamical behaviour of a cell signalling pathway may be described by means of a set of nonlinear ordinary differential equations. The data for parameter estimation are collected only at discrete time moments that are relatively rare. We show a gradient-based algorithm for parameter estimation. We also present some considerations about identifiability of cell signalling pathways. The approach is illustrated on a model of NF?B transcription factor pathway.

PL

Dynamiczne zachowanie komórkowych szlaków sygnałowych może być modelowane za pomocą nieliniowych równań różniczkowych zwyczajnych. Dane potrzebne do identyfikacji zbierane są w nielicznych, dyskretnych chwilach czasu. W artykule zamieszczamy gradientową metodę identyfikacji parametrów oraz przedstawiamy rozważania dotyczące identyfikowalności parametrów. Podejście jest zilustrowane na przykładzie modelu szlaku sygnałowego czynnika transkrypcyjnego NF?B.

7

Identifiability and estimation of pharmacokinetic parameters for the ligands of the macrophage mannose receptor

Verdiere N., Denis-Vidual L, Joly-Blanchard G., Domurado D.

International Journal of Applied Mathematics and Computer Science

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2005

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Vol. 15, no 4

517-526

EN

The aim of this paper is numerical estimation of pharmacokinetic parameters of the ligands of the macrophage mannose receptor, without knowing a priori the values of these parameters. However, it first requires a model identifiability analysis, which is done by applying an algorithm implemented in a symbolic computation language. It is shown that this step can lead to a direct numerical estimation algorithm. In this way, a first estimate is computed from noisy simulated observations without a priori parameter values. Then the resulting parameter estimate is improved by using the classical least-squares method.