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Tytuł:
Nonlinear modelling of Activated Sludge Process
Autorzy:
Frącz, P.
Powiązania:
https://bibliotekanauki.pl/articles/376011.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
nonlinear modeling
wastewater treatment
Activated Sludge Process
oxygen control
Opis:
A computer simulation model for the Activated Sludge Process (ASP) of a wastewater treatment plant (WWT) is presented in this paper. The model is based on non-linear equations, which depend on wastewater concentration and flow, which values vary with time. The proposed ASM1R3 model is a reduced version of the common ASM1 model due to the fact it involves only three state variables: Ss –the dissolved biodegradable organic substrate, SNO – the dissolved nitrate nitrogen and SNH – the dissolved ammonia nitrogen. In an experimental verification the model was considered as well fitted to empirical data. The proposed model is characterized by relatively low computational complexity and can be successfully applied as integral part of the overriding control systems of the WWT plant. As a result of conducted studies it was found that it is possible to apply the ASM1R3 model to optimize and improve the WWT process parameters of the regarded plant.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2016, 88; 187-197
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new approach to nonlinear modelling of dynamic systems based on fuzzy rules
Autorzy:
Bartczuk, Ł.
Przybył, A.
Cpałka, K.
Powiązania:
https://bibliotekanauki.pl/articles/330372.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
nonlinear modelling
dynamic system
fuzzy system
interpretability of fuzzy system
evolutionary algorithm
modelowanie nieliniowe
układ dynamiczny
system rozmyty
algorytm ewolucyjny
Opis:
For many practical weakly nonlinear systems we have their approximated linear model. Its parameters are known or can be determined by one of typical identification procedures. The model obtained using these methods well describes the main features of the system’s dynamics. However, usually it has a low accuracy, which can be a result of the omission of many secondary phenomena in its description. In this paper we propose a new approach to the modelling of weakly nonlinear dynamic systems. In this approach we assume that the model of the weakly nonlinear system is composed of two parts: a linear term and a separate nonlinear correction term. The elements of the correction term are described by fuzzy rules which are designed in such a way as to minimize the inaccuracy resulting from the use of an approximate linear model. This gives us very rich possibilities for exploring and interpreting the operation of the modelled system. An important advantage of the proposed approach is a set of new interpretability criteria of the knowledge represented by fuzzy rules. Taking them into account in the process of automatic model selection allows us to reach a compromise between the accuracy of modelling and the readability of fuzzy rules.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2016, 26, 3; 603-621
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modified pid control design for roll fin actuator of nonlinear modelling of the fishing boat
Autorzy:
Alarçin, F.
Demirel, H.
Su, M. E.
Yurtseven, A.
Powiązania:
https://bibliotekanauki.pl/articles/258902.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
stability analyses
nonlinear roll motion
modified PID
CFD
Opis:
This study aims to reduce roll motion of a fishing boat which arises from disturbing hydrodynamic effects by means of fin roll stabilizer. It is assured that roll motion with nonlinear damping and restoring moment coefficients are down to the desired level through classical PID and modified PID algorithms. At the time of sailing, stability, a very important concept, was examined using Lyapunov direct method taking initial conditions into consideration, and it was noted that the system was generally stable. In addition, NACA 0015 model was used for the fin roll stabilizer, and flow analysis was carried out with Computational Fluid Dynamics (CFD) method. In the simulation results, when the same gains were used, modified PID controller algorithms were relatively more effective compared to PID in the fin roll stabilizer system.
Źródło:
Polish Maritime Research; 2014, 1; 3-8
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear modelling of a bridge: A case study-based damage evaluation and proposal of Structural Health Monitoring (SHM) system
Autorzy:
Fawad, Muhammad
Koris, Kalman
Salamak, Marek
Gerges, Michael
Bednarski, Lukasz
Sienko, Rafal
Powiązania:
https://bibliotekanauki.pl/articles/2174024.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
most żelbetowy
metoda elementów skończonych
metoda nieniszcząca
monitorowanie stanu konstrukcji
pęknięcie
czujnik
reinforced concrete bridge
finite element method
non-destructive method
structural health monitoring
crack
sensor
Opis:
Monitoring and structural health assessment are the primary requirements for performance evaluation of damaged bridges. This paper highlights the case-study of a damaged Reinforced Concrete (RC) bridge structure by considering the outcomes of destructive testing, Non-Destructive Testing (NDT) evaluations, static and 3D non-linear analysis methods. Finite element (FE) modelling of this structure is being done using the material properties extracted by the in-situ testing. Analysis is carried out to evaluate the bridge damage based on the data recorded after the static linear (AXIS VM software) and 3D non-linear analysis (ATENA 3D software). Extensive concrete cracking and high value of crack width are found to be the major problems, leading to lowering the performance of the bridge. As a solution, this paper proposes a proper Structural Health Monitoring (SHM) system, that will extend the life cycle of the bridge with minimal repair costs and reduced risk of failure. This system is based on the installation of three different types of sensors: Liquid Levelling sensors (LLS) for measurement of vertical displacement, Distributed Fiber Optic Sensors (DFOS) for crack monitoring, and Weigh in Motion (WIM) devices for monitoring of moving loads on bridge.
Źródło:
Archives of Civil Engineering; 2022, 68, 3; 569--584
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast optimal feedback controller for electric linear actuator used in spreading systems of road spreaders
Autorzy:
Dobrowolski, D.
Dobrowolski, J.
Piekarska, W.
Stępień, S.
Powiązania:
https://bibliotekanauki.pl/articles/201515.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear electric actuator
nonlinear modelling
optimal feedback control
Opis:
Modern and innovative road spreaders are now equipped with a special swiveling mechanism of the spreading disc. It allows for adjusting asymmetrical or a symmetrical spreading pattern and provides for the possibility to maintain the size of the spreading surface and achieve an accurately defined spreading pattern with spreading widths. Thus the paper presents a modelling and control design methodology, and the concept is proposed to design high-performance and optimal drive systems for spreading devices. The paper deals with a nonlinear model of an electric linear actuator and solution of the new intelligent/optimal control problem for the actuator.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 6; 1041-1047
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controlling continuous bioreactor via nonlinear feedback: modelling and simulations approach
Autorzy:
Aguilar-López, R.
Neria-González, I.
Powiązania:
https://bibliotekanauki.pl/articles/200156.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nonlinear feedback
sulfate-reducing process
continuous bioreactors
Lyapunov stability
nieliniowe sprzężenie zwrotne
proces redukcji siarczanu
bioreaktor
metoda Lapunowa
Opis:
The aim of this work is to present a class of nonlinear controller with an exponential-type feedback in order to regulate the sulfate mass concentration via the input flow in a continuous stirred tank bioreactor of an anaerobic sulfate-reducing process. The corresponding kinetic terms in the bioreactor’s modeling are modeled by unstructured modeling approach, which was experimentally corroborated. A sketch of proof of the closed-loop stability of the considered system is done under the framework of Lyapunov theory. Numerical experiments are conducted to show the performance of the proposed methodology in comparison with a well-tuned sigmoid controller.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2016, 64, 1; 235-241
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of Nonlinear Crosstalk in Optical Fibre Wavelength-Division Multiplexed Telecommunication Systems
Autorzy:
Szczęsny, W.
Marciniak, M.
Powiązania:
https://bibliotekanauki.pl/articles/2008299.pdf
Data publikacji:
1999-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.-i
42.79.Sz
Opis:
Nonlinear effects in optical fibres play an important role for transmission parameters in wavelength-division multiplexed telecommunication systems. Those effects cause an additional attenuation, distortion and inter-channel interference of the multi-wavelength optical signal. Therefore, it is important to optimise inter-channel wavelength span in a wavelength-division multiplexed system, and also the optical power and transmission bit-rate. Another drawback is a limitation of the number of the transmitted optical channels and network nodes. The paper reports the results of the analysis and computer simulations of the wavelength-division multiplexed transmission through fibre link in a presence of nonlinear effects: self-phase modulation, cross-phase modulation, Raman scattering, four-wave mixing. The analysis enables network designers to evaluate the system performance and to optimise transmission parameters.
Źródło:
Acta Physica Polonica A; 1999, 95, 5; 859-867
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Modelling of Nonlinear Systems and Phenomena with the Use of Volterra and Wiener Series
Autorzy:
Borys, A.
Powiązania:
https://bibliotekanauki.pl/articles/116165.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Methods and Algorithms
nonlinear systems
Wiener Series
Modelling of Nonlinear Systems
Volterra Series
Discrete-Time Nonlinear Systems
Volterra Theory
Opis:
This is a short tutorial on Volterra and Wiener series applications to modelling of nonlinear systems and phenomena, and also a survey of the recent achievements in this area. In particular, we show here how the philosophies standing behind each of the above theories differ from each other. On the other hand, we discuss also mathematical relationships between Volterra and Wiener kernels and operators. Also, the problem of a best approximation of large-scale nonlinear systems using Volterra operators in weighted Fock spaces is described. Examples of applications considered are the following: Volterra series use in description of nonlinear distortions in satellite systems and their equalization or compensation, exploiting Wiener kernels to modelling of biological systems, the use of both Volterra and Wiener theories in description of ocean waves and in magnetic resonance spectroscopy. Moreover, connections between Volterra series and neural network models, and also input-output descriptions of quantum systems by Volterra series are discussed. Finally, we consider application of Volterra series to solving some nonlinear problems occurring in hydrology, navigation, and transportation.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2015, 9, 1; 91-98
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Understanding of Meyer and Stephens’s operator o as a multi-operational one
Autorzy:
Borys, A.
Powiązania:
https://bibliotekanauki.pl/articles/226031.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
operators and operations
operator o
Volterra series
weakly nonlinear circuits
modelling harmonic and intermodulation distortion
Opis:
In this paper, the idea of an extended operator o introduced in the literature on modelling weakly nonlinear circuits by Meyer and Stephens is revisited. The mathematically precise definitions of this operator for the successive Volterra series terms are given. Furthermore, the exhaustive formal and illustrative descriptions of these definitions are also presented. Finally, the possibility of a reverse formulation for the convolution operations occurring in descriptions of weakly nonlinear circuits is reported.
Źródło:
International Journal of Electronics and Telecommunications; 2016, 62, 3; 273-277
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear vibrations of periodic beams
Autorzy:
Domagalski, Ł.
Jędrysiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/280198.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
nonlinear vibrations
periodic beams
tolerance modelling
Opis:
Geometrically nonlinear vibrations of beams with properties periodically varying along the axis are investigated. The tolerance method of averaging differential operators with highly oscillating coefficients is applied to obtain governing equations with constant coefficients. The proposed model describes dynamics of the beam with the effect of microstructure size. In an example, an analysis of undamped forced nonlinear vibrations of the periodic beam is shown. Moreover, the results obtained for undamped free vibrations of periodic beams by the tolerance model are justified by those results from the finite element method. These results can be used as a benchmark in similar problems.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1095-1108
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Physical Model of the Nonlinear Sitar String
Autorzy:
Siddiq, S.
Powiązania:
https://bibliotekanauki.pl/articles/177221.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sitar
physical modelling
nonlinear string vibration
dispersion
Opis:
The acoustic properties of the sitar string are studied with the aid of a physical model. The nonlinearity of the string movement caused by the bridge acting as an obstacle to the vibrating string is of special interest. Comparison of the model’s audio output to recordings of the instrument shows interesting similarities. The effects dispersion and bridge have on the sound of the instrument are demonstrated in the model.
Źródło:
Archives of Acoustics; 2012, 37, 1; 73-79
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geometrically nonlinear vibrations of thin visco-elastic periodic plates on a foundation with damping: non-asymptotic modelling
Autorzy:
Jędrysiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/280289.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
thin visco-elastic periodic plates
nonlinear vibrations
effect of microstructure size
analytical tolerance modelling
Opis:
The objects under consideration are thin visco-elastic periodic plates with moderately large deflections. Geometrically nonlinear vibrations of these plates are investigated. In order to take into account the effect of microstructure size on behaviour of these plates a non- -asymptotic modelling method is proposed. Using this method, called the tolerance modelling, model equations with constant coefficients involving terms dependent on the microstructure size can be derived. In this paper, only theoretical considerations of the problem of nonlinear vibrations of thin visco-elastic periodic plates resting on a foundation with damping are presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 3; 945-961
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear vibrations of periodic beams
Autorzy:
Domagalski, Ł.
Jędrysiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/127716.pdf
Data publikacji:
2014
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
nonlinear vibrations
periodic beams
tolerance modelling
drgania nieliniowe
belka o strukturze periodycznej
modelowanie tolerancyjne
Opis:
Geometrically nonlinear vibrations of beams with properties periodically varying along the axis are investigated. The tolerance method of averaging differential operators with highly oscillating coefficients is applied to obtain the governing equations with constant coefficients. The proposed model describes the dynamics of the beam with the effect of the microstructure size.
Źródło:
Vibrations in Physical Systems; 2014, 26; 73-78
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A control algorithm applied to polarization states of light in the nonlinear optical resonator
Autorzy:
Wierzbicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/206554.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
dwustabilność optyczna
układ nieliniowy
inverse modelling
nonlinear systems
optical bistability
Opis:
In this paper a control algorithm is presented for a nonlinear system defined by a nonlinear mapping F : R^n -> R^n of input states to output states of the system, for the problem of motion in the R^n space of output states along the given trajectory. The application of this algorithm in nonlinear optics is presented, for the control of light polarization transmitted through the Fabry-Perot resonator filled with a material with nonlinear optical properties. The calculated trajectory in the space of polarization states of output light leads to the phenomenon of optical bistability, i.e. sudden changes of output polarization induced by small variations of the input parameters, and the dependence of the current state of light polarization on the history of the system.
Źródło:
Control and Cybernetics; 2002, 31, 1; 129-139
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of complex dynamic nonlinear loading process for electromagnetic mill
Autorzy:
Ogonowski, Szymon
Bismor, Dariusz
Ogonowski, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/229680.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
predictive control
pole placement
nonlinear dynamics
neural modelling
electromagnetic mill
Opis:
Electromagnetic mill installation for dry grinding represents a complex dynamical system that requires specially designed control system. The paper presents model-based predictive control which locates closed loop poles in arbitrary places. The controller performs as gains cheduling prototype where nonlinear model – artificial recurrent neural network, is parameterized with additional measurements and serves as a basis for local linear approximation. Application of such a concept to control electromagnetic mill load allows for stable performance of the installation and assures fulfilment of the product quality as well as the optimization of the energy consumption.
Źródło:
Archives of Control Sciences; 2020, 30, 3; 471-500
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Two Nonlinear Predictive Control Algorithms for Dissolved Oxygen Tracking Problem at WWTP
Autorzy:
Piotrowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/384859.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
aeration
dissolved oxygen
wastewater treatment
mathematical modelling
nonlinear system
predictive control
Opis:
The wastewater treatment plant is classified as a complex system due to its nonlinear dynamics, large uncertainty in the disturbance inputs, multiple time scales in the internal process dynamics and multivariable structure. Aeration is an important and expensive activity that is carried out during wastewater treatment plant operation. A precise aeration control in biological processes for all the operating conditions is necessary in order to guarantee adequate biological conditions for microorganisms. Therefore, the most important is to operate the biological processes so that a minimal energy was consumed and minimal DO concentration demand was applied. The paper proposes a two advanced control systems to track the dissolved oxygen reference trajectory. A decentralized and multivariable nonlinear predictive control algorithms are designed and compared. Simulation tests for the case study wastewater treatment plant are presented.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2016, 10, 1; 8-16
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time-varying time-delay estimation for nonlinear systems using neural networks
Autorzy:
Tan, Y.
Powiązania:
https://bibliotekanauki.pl/articles/907277.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
modelowanie procesu
opóźnienie czasowe
układ nieliniowy
sieć neuronowa
modelling
time delay
nonlinear systems
neural networks
estimation
Opis:
Nonlinear dynamic processes with time-varying time delays can often be encountered in industry. Time-delay estimation for nonlinear dynamic systems with time-varying time delays is an important issue for system identification. In order to estimate the dynamics of a process, a dynamic neural network with an external recurrent structure is applied in the modeling procedure. In the case where a delay is time varying, a useful way is to develop on-line time-delay estimation mechanisms to track the time-delay variation. In this paper, two schemes called direct and indirect time-delay estimators are proposed. The indirect time-delay estimator considers the procedure of time-delay estimation as a nonlinear programming problem. On the other hand, the direct time-delay estimation scheme applies a neural network to construct a time-delay estimator to track the time-varying time-delay. Finally, a numerical example is considered for testing the proposed methods.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2004, 14, 1; 63-68
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical modelling of metal-elastomer spring nonlinear response for low-rate deformations
Autorzy:
Sikora, W.
Michalczyk, K.
Machniewicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/386307.pdf
Data publikacji:
2018
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
bergström-boyce model
neidhart’s spring
metal-elastomer spring
FEM
SBR rubber
nonlinear spring
Opis:
Advanced knowledge of mechanical characteristics of metal-elastomer springs is useful in their design process and selection. It can also be used in simulating dynamics of machine where such elements are utilized. Therefore this paper presents a procedure for preparing and executing FEM modelling of a single metal-elastomer spring, also called Neidhart’s spring, for low-rate deformations. Elastomer elements were made of SBR rubber of two hardness values: 50°Sh and 70°Sh. For the description of material behaviour the Bergström-Boyce model has been used.
Źródło:
Acta Mechanica et Automatica; 2018, 12, 1; 31-37
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical modelling of the competition between the adaptive immune system and virus
Autorzy:
Kolev, M.
Powiązania:
https://bibliotekanauki.pl/articles/206177.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
numerical modelling
kinetic theory
active particles
integro-differential equations of Boltzmann type
nonlinear dynamics
virus
adaptive immune system
Opis:
We present and analyze numerically a mathematical model of interactions between adaptive immune system and viral infection. The model is a bilinear system of partial integro-differential equations of Boltzmann type. It is a generalization of the recently proposed kinetic models that consider particular (namely, the cellmediated and the humoral) immune mechanisms used in the fight against viral infections. We use Matlab to solve complicated system of equations, present the results of computer simulations and explain their immunological meaning. The results show that the model can describe in a better way (in comparison with the previous kinetic models) real biological situations and is able to illustrate various methods of therapy.
Źródło:
Control and Cybernetics; 2011, 40, 3; 763-778
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semi-analytical modelling of multilayer continuous systems nonlinear dynamics
Semi-analityczne modelowanie nieliniowej dynamiki wielowarstwowych układów ciągłych
Autorzy:
Koziol, P.
Pilecki, R.
Powiązania:
https://bibliotekanauki.pl/articles/231360.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metoda semi-analityczna
struktura wielowarstwowa
właściwości nieliniowe
odpowiedź dynamiczna
układ belki podwójnej
modelowanie
droga kolejowa
semi-analytical method
multilayer structure
nonlinear properties
dynamic response
double-beam
system
railway
modelling
Opis:
Problems concerning structures dynamics are being one of most important subjects in recent investigations associated with railways constructions. The need of modelling of such structures and their behaviour prediction leads to necessity of seeking new approaches, mainly due to highly increasing speeds of vehicles and traffic intensity. Comparative studies carried out on experimental data, measurements and theoretical research show that models based on multi-layered approach supported by semi-analytical approximations of solutions can give new insight into undertaken analyses. More detailed consideration of roads components and their physical properties, along with application of effective estimations allowing to avoid numerical instabilities linked with extremal dynamic variations, can be important tools in obtaining new solutions both, theoretical and engineering. This paper briefly presents a number of multilayer railway track models, with special emphasis on nonlinear track properties. Existing analytical and semi-analytical solution methods are presented with main advantages of new approaches. The theoretical double-beam system with two nonlinear layers is solved and computational examples are presented along with possibility of their transition to other multilayer structures analysis.
Problemy dynamiki konstrukcji stanowią jeden z najbardziej istotnych działów współczesnych badań związanych z konstrukcjami kolejowymi. Potrzeba modelowania takich konstrukcji oraz przewidywania ich dynamicznych oddziaływań prowadzi do konieczności poszukiwania nowych rozwiązań, głównie z powodu rosnących prędkości pojazdów i intensywności ruchu. Studia porównawcze prowadzone zarówno w ramach prac eksperymentalnych, pomiarowych, jak i teoretycznych rozważań pokazują, że modele wielowarstwowe w połączeniu z metodami semianalitycznymi mogą dać nowe spojrzenie na wyniki dotychczasowych analiz. Dokładniejsza analiza elementów drogi oraz ich fizycznych właściwości, razem z zastosowaniem efektywnych estymacji i aproksymacji pozwalających uniknąć numerycznych niestabilności spowodowanych ekstremalnymi dynamicznymi zmianami układów, mogą być ważnymi narzędziami służącymi otrzymaniu nowych rozwiązań, zarówno teoretycznych jak i inżynierskich. Artykuł ten prezentuje w skrócony sposób wybrane modele wielowarstwowe drogi kolejowej, ze szczególnym uwzględnieniem jej nieliniowych właściwości. Zostały omówione istniejące rozwiązania analityczne i semi-analityczne, ze wróceniem uwagi na korzyści płynące z ich zastosowania. Teoretyczny model belki podwójnej został rozwiązany. Pokazano przykłady obliczeniowe wraz z omówieniem możliwości ich adaptacji do analizy innych struktur wielowarstwowych. Dotychczas opublikowane prace zawierają interesujące wyniki semi-analityczne związane z założeniem nieliniowej sztywności elementów konstrukcji typu belka-podłoże. Modele jednowarstwowy i dwuwarstwowy zostały szczegółowo przeanalizowane przy założeniu nieliniowej sztywności podłoża, przy użyciu semi-analitycznej metody opartej na aproksymacjach falkowych połączonych z dekompozycją Adomiana. Modele te zostały również poddane walidacji poprzez porównanie wyników z pomiarami wykonanymi na rzeczywistym torze kolejowym, pokazujące wysoką zgodność rezultatów w zakresie drgań pionowych drogi kolejowej dla różnych zbiorów parametrów i prędkości pojazdów.
Źródło:
Archives of Civil Engineering; 2020, 66, 2; 165-178
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of thin periodic plates subjected to large deflections
Modelowanie cienkich płyt periodycznych o dużych ugięciach
Autorzy:
Domagalski, Ł.
Jędrysiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/395941.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
płyty periodyczne
zginanie nieliniowe
modelowanie tolerancyjne
periodic plates
nonlinear bending
tolerance modelling
Opis:
The objects under consideration are thin linear-elastic plates with periodic structure in planes parallel to the plate midplane, subjected to large (of the order of plate thickness) deflections. The main aim is to propose a mathematical model describing geometrically nonlinear problems of such plates, which is based on the tolerance averaging technique, cf. Woźniak et al. [3]. Results calculated for a special static problem by the tolerance model are compared with results obtained within the known tolerance linear model of thin plates.
W pracy rozpatrywane są cienkie, liniowo-sprężyste płyty o budowie periodycznej w płaszczyznach równoległych do płaszczyzny środkowej. Zagadnienia statyki i dynamiki tego rodzaju płyt w zakresie dużych ugięć opisane są układem równań różniczkowych nieliniowych o silnie oscylujących, periodycznych, nieciągłych współczynnikach (por. książka pod red. Woźniaka i in. [3]). W celu otrzymania równań o stałych współczynnikach zastosowano tu technikę tolerancyjnego uśredniania, omówioną w książce pod red. Woźniaka, Michalaka i Jędrysiaka [5]. Zaproponowano nieliniowy model tolerancyjny, opisujący nieliniowo-geometryczne zagadnienia cienkich płyt periodycznych. Model ten zastosowano do wyznaczenia ugięć dla danego obciążenia, a otrzymane wyniki porównano z wynikami uzyskanymi w ramach liniowego modelu tolerancyjnego.
Źródło:
Civil and Environmental Engineering Reports; 2010, 5; 133-148
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling and simulation of dynamic unilateral elasto-plastic contact of compact hard bodies
Autorzy:
Kowalska, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1986938.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
motion simulation
nonlinear dynamics
vibro-impact systems
Opis:
The problems of modelling, simulation and analysis of vibro-impact motion of compact hard bodies are considered. In particular, dynamic elasto-plastic contact is simulated by using Johnson's analytical model of spherical bodies' contact. The results are compared with behaviour of the system with discrete linear-perfectly plastic model of contact.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 3; 335-341
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Modelling for Production of Hot Strip of Magnesium Alloy
Autorzy:
Nam, A.
Prufert, U.
Kawalla, R.
Powiązania:
https://bibliotekanauki.pl/articles/99479.pdf
Data publikacji:
2014
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
magnesium coil heating
nonlinear heat transfer
numerical simulation
Opis:
The paper deals with a thermal modelling of a magnesium coil in the magnesium strip production. The magnesium coil heating is the preparation step for the magnesium hot strip rolling and occurs in the special air circulating furnace. The cooling of the coil takes place on the several steps such as a transport of coil after heating from the furnace to a mill coiler. The aim of the work is to develop a tool to accurately simulate the temperature distribution within coil during the magnesium coil heating in the furnace. The major thermal properties for material and furnace were determined indirectly based on experimental data. Simulation results are compared to data obtained from experimental trials.
Źródło:
Journal of Machine Engineering; 2014, 14, 1; 29-38
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A data driven fault isolation method based on reference faulty situations with application to a nonlinear chemical process
Autorzy:
Ragot, José
Mourot, Gilles
Kallas, Maya
Powiązania:
https://bibliotekanauki.pl/articles/2172122.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fault detection
fault isolation
nonlinear system
data modelling
kernel
wykrywanie uszkodzeń
izolacja uszkodzeń
układ nieliniowy
modelowanie danych
Opis:
The diagnosis of systems is one of the major steps in their control and its purpose is to determine the possible presence of dysfunctions, which affect the sensors and actuators associated with a system but also the internal components of the system itself. On the one hand, the diagnosis must therefore focus on the detection of a dysfunction and, on the other hand, on the physical localization of the dysfunction by specifying the component in a faulty situation, and then on its temporal localization. In this contribution, the emphasis is on the use of software redundancy applied to the detection of anomalies within the measurements collected in the system. The systems considered here are characterized by non-linear behaviours whose model is not known a priori. The proposed strategy therefore focuses on processing the data acquired on the system for which it is assumed that a healthy operating regime is known. Diagnostic procedures usually use this data corresponding to good operating regimes by comparing them with new situations that may contain faults. Our approach is fundamentally different in that the good functioning data allow us, by means of a non-linear prediction technique, to generate a lot of data that reflect all the faults under different excitation situations of the system. The database thus created characterizes the dysfunctions and then serves as a reference to be compared with real situations. This comparison, which then makes it possible to recognize the faulty situation, is based on a technique for evaluating the main angle between subspaces of system dysfunction situations. An important point of the discussion concerns the robustness and sensitivity of fault indicators. In particular, it is shown how, by non-linear combinations, it is possible to increase the size of these indicators in such a way as to facilitate the location of faults.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2022, 32, 4; 635--655
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement Results Based Approximation of the Nonlinear Flux-Current Characteristic of an Electromechanical Actuator
Autorzy:
Kowalik, Z.
Powiązania:
https://bibliotekanauki.pl/articles/114487.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
simplicial approximation
mathematical modelling
electrical measurements
flux-current characteristic
Opis:
A Hamiltonian model of an electromechanical actuator requires approximation of its flux-current characteristic. It can be made using a simplicial approximation, which requires the sets of corresponding points in the spaces of currents and fluxes. These points can be chosen from the trajectories that describe the behaviour of the electromechanical system in these spaces. In the paper, a method of obtaining these trajectories by measurements is shown and four original methods of choosing points lying on them to construct the required points sets are presented. The sets are constructed so that they contain a possibly small number of points, but the approximation which is based on them is precise. The presented methods are used to approximate a flux-current characteristic of the prototype synchronous reluctance machine. The simulation results, computed using the models based on these approximations, are also presented and discussed. The best results are obtained by methods using the computed value of the magnetic field coenergy in the modelled machine.
Źródło:
Measurement Automation Monitoring; 2016, 62, 2; 49-54
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
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