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Wyszukujesz frazę "linear stability" wg kryterium: Temat


Tytuł:
Investigation of the pad stiffness effects on the initiation of brake squeal phenomenon
Autorzy:
Yavuz, Akif
Sen, Osman
Powiązania:
https://bibliotekanauki.pl/articles/2200884.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
disc brake squeal
mode coupling phenomenon
linear stability analysis
nonlinear dynamics
Opis:
The main objective of this study is to investigate pad stiffness effects on the instability of a nonlinear brake squeal model. Hence, a nonlinear mathematical model is developed. The nonlinear model is linearized to check the system stability through complex eigenvalue analysis. The results of linear stability analyses are compared to the numerical solution of the nonlinear model, and it is observed that the dynamic behavior predicted by the linear stability analysis is in accordance with the numerical solutions. Though, a discrepancy may occur at the predicted squeal frequencies with both approaches, especially at high pad stiffness levels.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 219--232
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability of convex linear combinations of continuous-time and discrete-time linear systems
Autorzy:
Kaczorek, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/27324012.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
convex linear combination
linear system
continuous-time
discrete-time
positive
system
stability
Opis:
The asymptotic stability of the convex linear combination of continuous-time and discretetime linear systems is considered. Using the Gershgorin theorem it is shown that the convex linear combination of the linear asymptotically stable continuous-time and discretetime linear systems is also asymptotically stable. It is shown that the above thesis is also valid (even simpler) for positive linear systems.
Źródło:
Archives of Control Sciences; 2023, 33, 4; 789--799
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ADI-based, conditionally stable schemes for seismic P-wave and elastic wave propagation problems
Autorzy:
Łoś, Marcin
Behnoudfar, Pouria
Dobija, Mateusz
Paszyński, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/2173701.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conditional stability
P-wave propagation problems
elastic wave propagation problems
linear computational cost
time-dependent simulations
stabilność warunkowa
problemy z propagacją fali P
problemy z propagacją fali sprężystej
koszt obliczeniowy liniowy
symulacje zależne od czasu
Opis:
The modeling of P-waves has essential applications in seismology. This is because the detection of the P-waves is the first warning sign of the incoming earthquake. Thus, P-wave detection is an important part of an earthquake monitoring system. In this paper, we introduce a linear computational cost simulator for three-dimensional simulations of P-waves. We also generalize our formulations and derivation for elastic wave propagation problems. We use the alternating direction method with isogeometric finite elements to simulate seismic P-wave and elastic propagation problems. We introduce intermediate time steps and separate our differential operator into a summation of the blocks, acting along the particular coordinate axis in the sub-steps. We show that the resulting problem matrix can be represented as a multiplication of three multi-diagonal matrices, each one with B-spline basis functions along the particular axis of the spatial system of coordinates. The resulting system of linear equations can be factorized in linear O (N) computational cost in every time step of the semi-implicit method. We use our method to simulate P-wave and elastic wave propagation problems. We derive the condition for the stability for seismic waves; namely, we show that the method is stable when τ < C min{ hx,hy,hz}, where C is a constant that depends on the PDE problem and also on the degree of splines used for the spatial approximation. We conclude our presentation with numerical results for seismic P-wave and elastic wave propagation problems.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 5; art. no. e141985
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upper Bounds for the Complex Growth Rate of a Disturbance in Ferrothermohaline Convection
Autorzy:
Ram, Kaka
Prakash, Jyoti
Kumari, Kultaran
Kumar, Pankaj
Powiązania:
https://bibliotekanauki.pl/articles/2086773.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
linear stability
ferrofluid
oscillatory motions
ferrothermohaline convection
Opis:
It is proved analytically that the complex growth rate σ= σr+iσi (σr and σi are the real and imaginary parts of σ, respectively) of an arbitrary oscillatory motion of neutral or growing amplitude in ferrothermohaline convection in a ferrofluid layer for the case of free boundaries is located inside a semicircle in the right half of the σrσi-plane, whose center is at the origin (formula) where Rs is the concentration Rayleigh number, Pr′ is the solutal Prandtl number, M1′ is the ratio of magnetic flux due to concentration fluctuation to the gravitational force, and M5 is the ratio of concentration effect on magnetic field to pyromagnetic coefficient. Further, bounds for the case of rigid boundaries are also derived separately.
Źródło:
Studia Geotechnica et Mechanica; 2022, 44, 2; 114--122
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of the control parameters on the stability of a laminar boundary layer on a porous flat plate
Autorzy:
Lihonou, T. F.
Monwanou, A. V.
Miwadinou, C. H.
Chabi Orou, J. B.
Powiązania:
https://bibliotekanauki.pl/articles/2174178.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepuszczalność
liczba Reynoldsa
metoda kolokacji
permeability parameter
small Reynolds number
linear temporal stability
boundary layer
modified Orr-Sommerfeld equation
spectral collocation method
Opis:
This work is devoted to the analysis of the linear temporal stability of a laminar dynamic boundary layer on a horizontal porous plane plate. The basic flow is assumed to be laminar and two-dimensional. The basic flow velocity profiles are obtained by numerically solving the Blasius equation using the Runge-Kutta method. The perturbations of these basic solutions are expressed in the form of three-dimensional Tollmien-Schlichting waves. The formulation of the stability problem leads to the Orr-Sommerfeld equation modified by the permeability parameter (Darcy number) and the small Reynolds number. This equation is given in a general form which can be applied to the Chebyshev domain and the boundary layer domain and solved numerically using the Chebyshev spectral collocation method. The marginal stability diagrams, the critical Reynolds numbers and the eigenvalue spectra are obtained for different values of the parameters which have modified the stability equation. Numerical solutions indicate the importance of the effect of these parameters on the flow stability characteristics.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 4; 113--127
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An output sensitivity problem for a class of linear distributed systems with uncertain initial state
Autorzy:
Larrache, Abdelilah
Lhous, Mustapha
Rhila, Soukina Ben
Rachik, Mostafa
Tridane, Abdessamad
Powiązania:
https://bibliotekanauki.pl/articles/229238.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear system
distributed system
uncertain initial state
gain operators
observability
stability
linear programming
Opis:
In this paper,we consider an infinite dimensional linear systems. It is assumed that the initial state of system is not known throughout all the domain Ω C Rn, the initial state x0 ϵ L2(Ω) is supposed known on one part of the domain Ω and uncertain on the rest. That means Ω = ω1 U ω2 U... U ωt with ωi ∩ ωj = ∅, ∀i ≠ j ϵ {1,...,t}, i ≠ j where ωi ≠ ∅ and x0(θ) = αi for θ ϵ ωi, ∀i, i.e., x0(θ) = [wzór] (θ) where the values α1,...,αr are supposed known and αr+1,...,αt unknown and 1ωi is the indicator function. The uncertain part (α1,...,(α)rof the initial state x0 is said to be (ɛ1,...,ɛr )-admissible if the sensitivity of corresponding output signal (yi)i≥0 relatively to uncertainties (αk)1≤k≤r is less to the treshold ɛk, i.e., ∥∂yi)/(∂αk∥ ≤ ɛk, ∀i≥ 0, ∀k ϵ {1,...,r]. The main goal of this paper is to determine the set of all possible gain operators that makes the system insensitive to all uncertainties. The characterization of this set is investigated and an algorithmic determination of each gain operators is presented. Some examples are given.
Źródło:
Archives of Control Sciences; 2020, 30, 1; 139-155
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid nanobiocomposites based on poly(3-hydroxybutyrate) : characterization, thermal and mechanical properties
Autorzy:
Zarzycka, Iwona
Czerniecka-Kubicka, Anna
Szyszkowska, Agnieszka
Pyda, Marek
Frącz, Wiesław
Byczyński, Łukasz
Sedlarik, Vladimir
Powiązania:
https://bibliotekanauki.pl/articles/306831.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
nanoglinka
stabilność termiczna
właściwości mechaniczne
hybrid nanobiocomposites poly(3-hydroxybutyrate)
nanoclay
linear polyurethanes
thermal stability
mechanical properties
Opis:
Poly(3-hydroxybutyrate) is a biopolymer used to production of implants in the human body. On the other hand, the physical and mechanical properties of poly(3-hydroxybutyrate) are compared to the properties of isotactic polypropylene what makes poly(3-hydroxybutyrate) possible substitute for polypropylene. Unfortunately, the melting point of poly(3-hydroxybutyrate) is almost equal to its degradation temperature what gives very narrow window of its processing conditions. Therefore, numerous attempts are being made to improve the poly(3-hydroxybutyrate) properties. In the present work, hybrid nanobiocomposites based on poly(3-hydroxybutyrate) as a matrix with the use of organic nanoclay – Cloisite 30B and linear polyurethane as a second filler have been manufactured. The linear polyurethane was based on diphenylmethane 4,4′-diisocyanate and diol with imidazoquinazoline rings. The obtained nanobiocomposites were characterized by X-ray diffraction, scanning and transmission electron microscopies, thermogravimetry, differential scanning calorimetry and their selected mechanical properties were tested. The resulting hybrid nanobiocomposites have intercalated/exfoliated structure. The nanobiocomposites are characterized by a higher thermal stability and a wider range of processing temperatures compared to the unfilled matrix. The plasticizing influence of nanofillers was also observed. In addition, the mechanical properties of the discussed nanobiocomposites were examined and compared to those of the unfilled poly(3-hydroxybutyrate). The new-obtained nanobiocomposites based on poly(3-hydroxybutyrate) containing 1% Cloisite 30B and 5 wt. % of the linear of polyurethane characterized the highest improvement of processing conditions. They have the biggest difference between the temperature of degradation and the onset melting temperature, about 100 °C.
Źródło:
Acta of Bioengineering and Biomechanics; 2020, 22, 1; 97-110
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
LMI based stability criterion for uncertain neutral-type neural networks with discrete and distributed delays
Autorzy:
Baskar, P.
Padmanabhan, S.
Syed Ali, M.
Powiązania:
https://bibliotekanauki.pl/articles/2049954.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
stability analysis
neutral networks
Lyapunov method
Linear Matrix Inequality
Opis:
This paper studies the problem of robust stability analysis for uncertain neutral-type neural networks with discrete and distributed delays. By constructing an appropriate Lyapunov- Krasovskii functional, new delay-dependent criteria are obtained. We utilized the free-weighting matrices approach and bounding lemmas to estimate the derivative of the Lyapunov-Krasovskii functional. The stability criterion are established in terms of linear matrix inequalities (LMIs). Finally, a numerical example is presented to illustrate the effectiveness of the proposed method.
Źródło:
Control and Cybernetics; 2020, 49, 1; 77-97
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena stabilności posturalnej w funkcji różnego ustawienia stóp na podłożu przy wykorzystaniu miar dynamiki nieliniowej
Assessment of postural stability as a function of changing support surface
Autorzy:
Kędziorek, Justyna
Błażkiewicz, Michalina
Powiązania:
https://bibliotekanauki.pl/articles/2201496.pdf
Data publikacji:
2020
Wydawca:
Politechnika Śląska. Katedra Biomechatroniki
Tematy:
stabilność posturalna
miary nieliniowe
biomechanika
postural stability
non-linear measures
biomechanics
Opis:
Celem pracy była ocena stabilności posturalnej w różnych warunkach podparcia: stanie obunóż, jednonóż i w tandemie przy oczach otwartych. W badaniach wzięła udział grupa trzydziestu trzech zdrowych osób w wieku 21.88 ± 1.65 lat. Badania zostały przeprowadzone przy użyciu platformy AMTI AccuSway (30 sekund – każda próba). Do obliczeń eksportowano położenia środka nacisku stóp na podłoże (CoP) w płaszczyznach x i y. Następnie została policzona długość drogi CoP i współczynniki dynamiki nieliniowej: entropia próbkowa, wymiar fraktalny i wykładnik Lapunowa. Wykazano, że zmniejszenie pola powierzchni podparcia powoduje istotny wzrost współczynnika entropii próbkowej i wymiaru fraktalnego.
The aim of the study was to assess postural stability under different base of support: both foot standing, one-leg standing and tandem with eyes open. A group of thirty-three healthy persons aged 21.88 ± 1.65 years participated in the study. The tests were carried out using the AMTI AccuSway platform. The locations of the center of foot pressure (CoP) in the X and Y planes were exported. Then the CoP path length and nonlinear dynamics coefficients were calculated: sample entropy, fractal dimension and Lapunov exponent. It has been shown that the reduction of the support surface area causes a significant increase in the sample entropy factor and the fractal dimension.
Źródło:
Aktualne Problemy Biomechaniki; 2020, 19; 20--26
1898-763X
Pojawia się w:
Aktualne Problemy Biomechaniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability and stabilization of positive linear dynamical systems: new equivalent conditions and computations
Autorzy:
Yang, H.
Hu, Y.
Powiązania:
https://bibliotekanauki.pl/articles/201932.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
positive linear systems
stability
stabilization
linear inequalities systems
consistency
I-rank
Opis:
New equivalent conditions of the asymptotical stability and stabilization of positive linear dynamical systems are investigated in this paper. The asymptotical stability of the positive linear systems means that there is a solution for linear inequalities systems. New necessary and sufficient conditions for the existence of solutions of the linear inequalities systems as well as the asymptotical stability of the linear dynamical systems are obtained. New conditions for the stabilization of the resultant closed-loop systems to be asymptotically stable and positive are also presented. Both the stability and the stabilization conditions can be easily checked by the so-called I-rank of a matrix and by solving linear programming (LP). The proposed LP has compact form and is ready to be implemented, which can be considered as an improvement of existing LP methods. Numerical examples are provided in the end to show the effectiveness of the proposed method.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 2; 307-315
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Моделі управління показниками банку для забезпечення необхідного рівня фінансової стійкості
Bank indicators management models for ensure of financial stability necessary leve
Modele zarządzania wskaźnikami bankowymi dla zapewnienia niezbędnego poziomu stabilności finansowej
Autorzy:
Chemchykalenko, Ruslan
Dubrovina, Vira
Hrebenyuk, Nadiia
Powiązania:
https://bibliotekanauki.pl/articles/38112393.pdf
Data publikacji:
2020
Wydawca:
Wyższa Szkoła Techniczna w Katowicach
Tematy:
financial stability
linear trend
structural model
regression model
cluster
stabilność finansowa
trend liniowy
model strukturalny
modele regresji
Opis:
This article constructs linear trend models for the main indicators of the balance sheet and net profit of a state bank and determines their forecast values. The structural management model for the basic indicators of the state of bank is constructed and regression equations are used. For structural regression models, growth rates and their lag values were chosen, and lag in the 1st and 2nd time periods was used for modelling. Based on the graphical analysis, it is shown that there are dependences between the indicators of financial autonomy and indicators of return on assets and equity and two clusters are distinguished: the cluster of financial stability and the cluster of unstable financial positions of the bank. Based on the structural model and its parameters, according to the state of bank, the development of a sustainable development strategy is proposed, in which special attention should be paid to planning and forecasting key indicators, their complex functional relationships taking into account the time factor, random factors and their impact on state of bank and its financial stability.
W artykule autorzy budują liniowy model trendu dla głównych wskaźników bilansu i zysku netto banku państwowego oraz określają ich prognozowane wartości. Skonstruowano strukturalny model zarządzania podstawowymi wskaźnikami banku państwa, w którym wykorzystuje się równania regresji. W przypadku modeli regresji strukturalnej wybrano stopy wzrostu i ich wartości opóźnienia, a do modelowania wykorzystano opóźnienie w pierwszym i drugim okresie. Na podstawie analizy graficznej wykazano, że istnieją złożone formy zależności między wskaźnikami autonomii finansowej a wskaźnikami zwrotu z majątku i kapitału oraz wyróżnia się dwa klastry: klaster stabilności finansowej oraz klaster niestabilnych pozycji finansowych banku. Zdaniem Banku Państwowego, w oparciu o model strukturalny i jego parametry, proponuje się opracowanie strategii zrównoważonego rozwoju. W której szczególną uwagę należy zwrócić na planowanie i prognozowanie kluczowych wskaźników. Ich złożonych zależności funkcjonalnych z uwzględnieniem czynnika czasu, czynników losowych oraz ich wpływu na wynik finansowy banku oraz na jego stabilność.
Źródło:
Zeszyty Naukowe Wyższej Szkoły Technicznej w Katowicach; 2020, 12; 219-228
2082-7016
2450-5552
Pojawia się w:
Zeszyty Naukowe Wyższej Szkoły Technicznej w Katowicach
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new D-stability area for linear discrete-time systems
Autorzy:
Krokavec, Dušan
Filasová, Anna
Powiązania:
https://bibliotekanauki.pl/articles/229462.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
discrete-time linear systems
state control
pole placement onstraints
D-stability region
linear matrix inequalities
polytopic uncertainties
Opis:
The paper addresses the problem of constrained pole placement in discrete-time linear systems. The design conditions are outlined in terms of linear matrix in equalities for the D-stable ellipse region in the complex Z plain. In addition, it is demonstrated that the D-stable circle region formulation is the special case of by this way formulated and solved pole placement problem. The proposed principle is enhanced for discrete-time linear systems with polytopic uncertainties.
Źródło:
Archives of Control Sciences; 2019, 29, 1; 5-23
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymptotic properties of discrete linear fractional equations
Autorzy:
Anh, P. T.
Babiarz, A.
Czornik, A.
Niezabitowski, M.
Siegmund, S.
Powiązania:
https://bibliotekanauki.pl/articles/200917.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear discrete-time fractional systems
Caputo equation
Riemann-Liouville equation
Volterra convolution equation
stability
Opis:
In this paper we study the dynamical behavior of linear discrete-time fractional systems. The first main result is that the norm of the difference of two different solutions of a time-varying discrete-time Caputo equation tends to zero not faster than polynomially. The second main result is a complete description of the decay to zero of the trajectories of one-dimensional time-invariant stable Caputo and Riemann-Liouville equations. Moreover, we present Volterra convolution equations, that are equivalent to Caputo and Riemann-Liouvile equations and we also show an explicit formula for the solution of systems of time-invariant Caputo equations.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 4; 749-759
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Invariant properties of positive linear electrical circuits
Autorzy:
Kaczorek, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/377307.pdf
Data publikacji:
2019
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
invariance
positive
linear
system
stability
reachability
transfer matrix
Opis:
The invariant properties of the stability, reachability, and transfer matrices of positive linear electrical circuits with integer and fractional orders are investigated. It is shown that the stability, reachability and transfer matrix of positive linear systems are invariant under their integer and fractional orders.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2019, 97; 109-123
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Invariant properties of positive linear electrical circuits
Autorzy:
Kaczorek, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/141246.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
invariance
positive linear system
reachability
stability
transfer matrix
Opis:
The invariant properties of the stability, reachability, observability and transfer matrices of positive linear electrical circuits with integer and fractional orders are investigated. It is shown that the stability, reachability, observability and transfer matrix of positive linear systems are invariant under their integer and fractional orders.
Źródło:
Archives of Electrical Engineering; 2019, 68, 4; 875-890
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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