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Добірка наукової літератури з теми "Modes oscillatoire"

Автор: Grafiati

Опубліковано: 11 вересня 2022

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Статті в журналах з теми "Modes oscillatoire"

Cairns, David E., Roland J. Baddeley, and Leslie S. Smith. "Constraints on Synchronizing Oscillator Networks." Neural Computation 5, no. 2 (March 1993): 260–66. http://dx.doi.org/10.1162/neco.1993.5.2.260.

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This paper investigates the constraints placed on some synchronized oscillator models by their underlying dynamics. Phase response graphs are used to determine the phase locking behaviors of three oscillator models. These results are compared with idealized phase response graphs for single phase and multiple phase systems. We find that all three oscillators studied are best suited to operate in a single phase system and that the requirements placed on oscillatory models for operation in a multiple phase system are not compatible with the underlying dynamics of oscillatory behavior for these types of oscillator models.

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Velichko, Andrey, Maksim Belyaev, Vadim Putrolaynen, Alexander Pergament, and Valentin Perminov. "Switching dynamics of single and coupled VO2-based oscillators as elements of neural networks." International Journal of Modern Physics B 31, no. 02 (January 18, 2017): 1650261. http://dx.doi.org/10.1142/s0217979216502611.

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In the present paper, we report on the switching dynamics of both single and coupled VO2-based oscillators, with resistive and capacitive coupling, and explore the capability of their application in oscillatory neural networks. Based on these results, we further select an adequate SPICE model to describe the modes of operation of coupled oscillator circuits. Physical mechanisms influencing the time of forward and reverse electrical switching, that determine the applicability limits of the proposed model, are identified. For the resistive coupling, it is shown that synchronization takes place at a certain value of the coupling resistance, though it is unstable and a synchronization failure occurs periodically. For the capacitive coupling, two synchronization modes, with weak and strong coupling, are found. The transition between these modes is accompanied by chaotic oscillations. A decrease in the width of the spectrum harmonics in the weak-coupling mode, and its increase in the strong-coupling one, is detected. The dependences of frequencies and phase differences of the coupled oscillatory circuits on the coupling capacitance are found. Examples of operation of coupled VO2 oscillators as a central pattern generator are demonstrated.

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Feng, Chunhua. "Dynamic Behavior for a Coupled Nonlinear Oscillator Model with Distributed and Discrete Delays." European Journal of Mathematics and Statistics 2, no. 3 (July 9, 2021): 32–36. http://dx.doi.org/10.24018/ejmath.2021.2.3.43.

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— In this paper, the oscillatory behavior of the solutions for a coupled nonlinear oscillator model with distributed and discrete delays is investigated. Time delay induced partial death patterns with conjugate coupling in relay oscillators has been investigated in the literature. According to the practical problem, the propagation delays are not only the discrete delays, but also with distributed delay. A model includes distributed and discrete delays is considered. By mathematical analysis method, the oscillatory behavior of the coupled nonlinear oscillator model is brought to the instability of the uniqueness equilibrium point and the boundedness of the solutions. Some sufficient conditions are provided to guarantee the oscillation of the solutions. Computer simulations are given to support the present results. Our simulation suggests that the two theorems are only sufficient conditions.

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LABBI, ABDERRAHIM, RUGGERO MILANESE, and HOLGER BOSCH. "ASYMPTOTIC SYNCHRONIZATION IN NETWORKS OF LOCALLY CONNECTED OSCILLATORS." International Journal of Bifurcation and Chaos 09, no. 12 (December 1999): 2279–84. http://dx.doi.org/10.1142/s0218127499001759.

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In this paper, we describe the asymptotic behavior of a network of locally connected oscillators. The main result concerns asymptotic synchronization. The presented study is stated in the framework of neuronal modeling of visual object segmentation using oscillatory correlation. The practical motivations of the synchronization analysis are based on neurophysiological experiments which led to the assumptions that existence of temporal coding schemes in the brain by which neurons, with oscillatory dynamics, coding for the same coherent object synchronize their activities, while neurons coding for different objects oscillate with nonzero phase lags. The oscillator model considered is the FitzHugh–Nagumo neuron model. We restrict our study to the mathematical analysis of a network of such neurons. We firstly show the motivations and suitability of choosing FitzHugh–Nagumo oscillator, mainly for stimulus coding purposes, and then we give sufficient conditions on the coupling parameters which guarantee asymptotic synchronization of oscillators receiving the same external stimulation (input). We have used networks of such oscillators to design a layered architecture for object segmentation in gray-level images. Due to space limitations, description of this architecture and simulation results are briefly referred to by the end of the paper.

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UETA, TETSUSHI, HISAYO MIYAZAKI, TAKUJI KOUSAKA, and HIROSHI KAWAKAMI. "BIFURCATION AND CHAOS IN COUPLED BVP OSCILLATORS." International Journal of Bifurcation and Chaos 14, no. 04 (April 2004): 1305–24. http://dx.doi.org/10.1142/s0218127404009983.

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Bonhöffer–van der Pol(BVP) oscillator is a classic model exhibiting typical nonlinear phenomena in the planar autonomous system. This paper gives an analysis of equilibria, periodic solutions, strange attractors of two BVP oscillators coupled by a resister. When an oscillator is fixed its parameter values in nonoscillatory region and the others in oscillatory region, create the double scroll attractor due to the coupling. Bifurcation diagrams are obtained numerically from the mathematical model and chaotic parameter regions are clarified. We also confirm the existence of period-doubling cascades and chaotic attractors in the experimental laboratory.

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Kabana, Sonia, and Peter Minkowski. "Counting of oscillatory modes of valence quarks forming q–q̄ mesons." International Journal of Modern Physics A 31, no. 07 (March 2, 2016): 1650023. http://dx.doi.org/10.1142/s0217751x16500238.

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We present the unique properties of oscillatory modes of valence quarks [Formula: see text] and antiquarks in mesons and the mass spectrum of associated mesons. The mesonic multiplets are shown to emerge from the picture of oscillating quarks and antiquarks in three space dimensions in the center of mass system of the mesons. All oscillatory modes are fully relativistic with a finite number of oscillators and this is forming the unique harmonic oscillator with these properties. The density of states as a function of masssquare is calculated. Since it is known that there are missing states of unobserved hadrons this estimate is of relevance for the accounting of the latter, as the here estimated mesonic multiplets include both the observed and the unobserved (or “missing”) hadrons. The estimate is conceptually different from Hagedorn’s model and is based on field theory of QCD.

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Yeremieiev, Volodymyr, Oleksandr Briantsev, Oleksii Naumuk, and Volodymyr Samoilov. "Software for research oscillation process in the system of oscillators with different masses." Ukrainian Journal of Educational Studies and Information Technology 7, no. 4 (December 30, 2019): 10–23. http://dx.doi.org/10.32919/uesit.2019.04.02.

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A mathematical model is formulated as a system of differential equations for the analysis of the oscillatory process in a linear oscillators with different masses. It is assumed that the left end of the first oscillator is fixed and an arbitrary force is attached to the last oscillator. Proposed an algorithm for solving the problem using the numerical methods Euler and Runga-Kutt. Two Euler and RungK applications have been developed for calculations. The program code is compiled in C++ algorithmic language in Microsoft Visual Studio 2012. The accuracy of the calculated data depends on the number of oscillators and the time of oscillation. Testing showed that in the case of one or two oscillators, the program RungK, based on the Rung-Kutta method, provides 10-10% accuracy of calculations. The error of the calculated parameters is almost independent of the number of time intervals from 103 to 106. The accuracy of the Euler method, which is implemented in Euler, is about 0.5% under similar conditions. Increasing the number of iterations to 104, 105, and 106 leads to an increase in accuracy to 0.05%, 0.005%, and 0.0005%, respectively. The program can be useful in the analysis of oscillatory processes in a linear oscillate ditch.

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Kabana, Sonia, and Peter Minkowski. "Counting of oscillatory modes of valence quarks forming qqq baryons for three quark flavors u, d, s." International Journal of Modern Physics A 32, no. 04 (February 9, 2017): 1750004. http://dx.doi.org/10.1142/s0217751x1750004x.

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We present the unique properties of oscillatory modes of [Formula: see text] light quarks — [Formula: see text], [Formula: see text], [Formula: see text] — using the [Formula: see text] broken symmetry classification. [Formula: see text] stands for the space rotation group generated by the sum of the three individual angular momenta of quarks in their c.m. system. The baryonic multiplets are shown to emerge from the picture of oscillating quarks in three space dimensions in the center-of-mass system of the baryons. All oscillatory modes are fully relativistic with a finite number of oscillators and this is forming the unique harmonic oscillator with these properties. The density of states as a function of mass-square is calculated. This estimate is of relevance for the accounting of the missing states of unobserved hadrons, as the here estimated baryonic multiplets include both the observed and the unobserved (or “missing”) hadrons. The estimate is conceptually different from Hagedorn’s model and is based on field theory of QCD.

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Jezzini, Sami H., Andrew A. V. Hill, Pavlo Kuzyk, and Ronald L. Calabrese. "Detailed Model of Intersegmental Coordination in the Timing Network of the Leech Heartbeat Central Pattern Generator." Journal of Neurophysiology 91, no. 2 (February 2004): 958–77. http://dx.doi.org/10.1152/jn.00656.2003.

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To address the general problem of intersegmental coordination of oscillatory neuronal networks, we have studied the leech heartbeat central pattern generator. The core of this pattern generator is a timing network that consists of two segmental oscillators, each of which comprises two identified, reciprocally inhibitory oscillator interneurons. Intersegmental coordination between the segmental oscillators is mediated by synaptic interactions between the oscillator interneurons and identified coordinating interneurons. The small number of neurons (8) and the distributed structure of the timing network have made the experimental analysis of the segmental oscillators as discrete, independent units possible. On the basis of this experimental work, we have made conductance-based models to explore how intersegmental phase and cycle period are determined. We show that although a previous simple model, which ignored many details of the living system, replicated some essential features of the living system, the incorporation of specific cellular and network properties is necessary to capture the behavior of the system seen under different experimental conditions. For example, spike frequency adaptation in the coordinating interneurons and details of asymmetries in intersegmental connectivity are necessary for replicating driving experiments in which one segmental oscillator was injected with periodic current pulses to entrain the activity of the entire network. Nevertheless, the basic mechanisms of phase and period control demonstrated here appear to be very general and could be used by other networks that produce coordinated segmental motor outflow.

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Kurkin, Semen A., Danil D. Kulminskiy, Vladimir I. Ponomarenko, Mikhail D. Prokhorov, Sergey V. Astakhov, and Alexander E. Hramov. "Central pattern generator based on self-sustained oscillator coupled to a chain of oscillatory circuits." Chaos: An Interdisciplinary Journal of Nonlinear Science 32, no. 3 (March 2022): 033117. http://dx.doi.org/10.1063/5.0077789.

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We have proposed and studied both numerically and experimentally a multistable system based on a self-sustained Van der Pol oscillator coupled to passive oscillatory circuits. The number of passive oscillators determines the number of multistable oscillatory regimes coexisting in the proposed system. It is shown that our system can be used in robotics applications as a simple model for a central pattern generator (CPG). In this case, the amplitude and phase relations between the active and passive oscillators control a gait, which can be adjusted by changing the system control parameters. Variation of the active oscillator’s natural frequency leads to hard switching between the regimes characterized by different phase shifts between the oscillators. In contrast, the external forcing can change the frequency and amplitudes of oscillations, preserving the phase shifts. Therefore, the frequency of the external signal can serve as a control parameter of the model regime and realize a feedback in the proposed CPG depending on the environmental conditions. In particular, it allows one to switch the regime and change the velocity of the robot’s gate and tune the gait to the environment. We have also shown that the studied oscillatory regimes in the proposed system are robust and not affected by external noise or fluctuations of the system parameters. Moreover, using the proposed scheme, we simulated the type of bipedal locomotion, including walking and running.

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Більше джерел

Дисертації з теми "Modes oscillatoire"

Anstie, James D. "A 50 K dual-mode sapphire oscillator and whispering spherical mode oscillators." University of Western Australia. School of Physics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0070.

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[Truncated abstract] This thesis is split into two parts. In part one; A 50 K dual mode oscillator, the aim of the project was to build a 50 K precision oscillator with frequency stability on the order of 1014 from 1 to 100 seconds. A dual-mode temperature compensation technique was used that relied on a turning point in the frequency-temperature relationship of the difference frequency between two orthogonal whispering gallery modes in a single sapphire crystal. A cylindrical sapphire loaded copper cavity resonator was designed, modelled and built with a turning point in the difference frequency between an E-mode and H-mode pair at approximately 52.5 K . . . The frequencies and Q-factors of whispering spherical modes in the 3-12 GHz range in the fused silica resonator are measured at 6, 77 and 300 K and the Q-factor is used to determine the loss tangent at these temperatures. The frequency and Q-factor temperature dependence of the TM2,1,2 whispering gallery mode at 5.18 GHZ is used to characterise the loss tangent and relative permittivity of the fused silica from 4-300 K. Below 22 K the frequency-temperature dependence of the resonator was found to be consistent with the combined effects of the thermal properties of the dielectric and the influence of an unknown paramagnetic impurity, with a spin resonance frequency at about 138 ± 31 GHz. Below 8 K the loss tangent exhibited a 9th order power law temperature dependence, which may be explained by Raman scattering of Phonons from the paramagnetic impurity ions. A spherical Bragg reflector resonator made from multiple concentric dielectric layers loaded in a spherical cavity that enables confinement of field in the centre of the resonator is described. A set of simultaneous equations is derived that allow the calculation of the required dimensions and resonance frequency for such a resonator and the solution is confirmed using finite element analysis. A spherical Bragg reflector resonator is constructed using Teflon and free-space as the dielectric materials. A Q-factor of 22,000 at 13.87 GHz was measured and found to compare well with the design values.

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Abdulhay, Enas. "Une nouvelle méthode non-invasive d'estimation cycle à cycle du volume d'éjection cardiaque dans le signal de plethysmographie respiratoire par inductance : algorithme de "double décomposition empirique"." Université Joseph Fourier (Grenoble ; 1971-2015), 2009. http://www.theses.fr/2009GRE10220.

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L'objectif principal qui guide les développements en traitement du signal de cette thèse est la mise au point d'un outil qui s'inscrit dans une démarche de physiologie intégrative où, à chaque échelle, le modèle des signaux peut être différent On cherche ici à restreindre le jeu d'hypothèses a priori à un ensemble de règles physiologiques qui régissent les interactions entre functions physiologiques en l'absence d'hypothèses fonnelles et: mathématiques sur les signaux. Nous avons appliqué cette démarche au problème de la détection des ondes cardiaques et: de l' estimation cycle à cycle du volume d'éjection dans le signal RIP (Respiratoty Inductive Plethysmography). L'approche par décomposition empirique se prête particulièrement à notre logique. Nous proposons ici la première version d'un algorithme basé sur une double décomposition empirique du signal RIP. La méthode choisie et: les outils correspondants ont été testés sur deux types de données, d'une part des signaux simulés, d'autre part des signaux enregistrés sur volontaires sains. Notre objectif est donc aussi de mettre au point un modèle cardiorespiratoire pouvant servir d'outil de simulation des signaux ventilatoires, cardiaques et: de RIP avec la simulation de l'effet de chaque système sur l'autre. Les résultats montrent que la méthode proposée est adaptée à l'analyse du signal RIP et: à l' estimation du volume d'éjection
The main objective that guides the signal processing approaches ofthis thesis is the development of a tool that oould be part of an integrative physiology approach where, at each scale, the model of signais may be different We seek here the restriction of asstnnptions a priori to a set: of rules goveming the physiological interactions between physiological functions in the absence of fannal and mathematical assumptions. We applied this approach to the problem of cardiac waves detection and estimation of cycle-to-cycle stroke volume in the RIP signal (Respiratory Inductive Plethysmography). The empirical decomposition approach seems to be particularly adapted to our logic. We propose here the first version of an algorithm based on RIP double decomposition. The method and its COITeSpül1ding tools have been tested on two types of data, simulated signais and real signais recorded at healthy volunteers. Our aim is also therefore to develop a cardio-respiratory model that can serve as a tool for ventilatory, cardiac and RIP signals simulation along with the simulation of the effect of each system on the other. The results show that the proposed method is suitable for RIP signal analysis and for stroke volume estimation

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JANIAUD, BEATRICE. "Instabilites de phase de modes oscillatoires." Paris 6, 1994. http://www.theses.fr/1994PA066156.

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Cette these est consacree a l'etude experimentale de la stabilite de modes oscillatoires non-lineaires. Comme dans le cas des structures dissipatives stationnaires, les instabilites se manifestent par des perturbations de phase ; toutefois leur nature oscillante fait apparaitre de nouveaux types de defauts localises. Nous avons etudie une structure unidimensionnelle, l'instabilite oscillatoire des rouleaux de convection de rayleigh-benard et une structure bidimensionnelle d'electro-convection d'un cristal liquide. La zone de stabilite du train d'onde unidimensionnel est limitee par l'instabilite d'eckhaus propagative, qui peut etre sur-critique. Par ailleurs nous avons mis en evidence des defauts localises, les trous de nozaki-bekki, qui sont une generalisation des dislocations spatio-temporelles. L'etude du mode optique de la structure bidimensionnelle a mis en evidence un couplage entre le reseau sous-jacent et le mode oscillatoire. Cette instabilite, correspondant a des deformations du reseau, conduit a l'apparition d'une structure localisee, en forme de cible. Pour chacune de ces trois instabilites, une comparaison quantitative avec l'equation complexe de landau-ginzburg et des simulations numeriques nous a permis de comprendre les mecanismes mis en jeu

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Mukherjee, Jayanta. "General non linear perturbation model of phase noise in LC oscillators." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1149061925.

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Barbagallo, Alexandre. "Model reduction and closed-loop control of oscillator and noise-amplifier flows." Palaiseau, Ecole polytechnique, 2011. https://pastel.hal.science/docs/00/65/49/30/PDF/Barbagallo_PhDThesis.pdf.

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This work deals with the closed-loop control of disturbances which develop linearly in laminar and incompressible flows. The control of both oscillator and amplifier flows is assessed. We consider a LQG control strategy in which the control law is computed using a reduced-order model of the flow. This reduced-order model is obtained by a Petrov-Galerkin projection. The first part is devoted to the stabilization of an open cavity flow which behaves as an oscillator. It is shown that the unstable subspace of the flow (the unstable global modes) and the input-output behaviour between the actuator and the sensor of the stable subspace must be captured by the reduced-order model to stabilize the system. Global modes, POD modes and BPOD modes are successively evaluated as projection bases to construct a reduced-order model of the stable part of the flow. It appears that global modes are not able to reproduce the input-output behaviour of the stable part of the flow and subsequently may only stabilize the flow if the instability is very weak (close to the criticality). On the contrary, reduced-order models based on POD modes and BPOD modes efficiently extract the input-output dynamic of the stable subspace and are successful to stabilize the flow. The second part of this work is dedicated to the reduction of the disturbances' amplification on a backward facing step. The influence of the sensor's location and of the cost functional on the performance of the compensator is studied. It is shown that the truncation of the reduced-order model may lead to an unstable closed-loop system. Finally, the possibility to control a non-linear simulation using a linear compensator is evaluated
Ce travail est consacré au contrôle en boucle fermée des perturbations se développant linéairement dans des écoulements laminaires et incompressibles de types oscillateurs et amplificateurs de bruit. La loi de contrôle, calculée selon la théorie du contrôle LQG, est basée sur un modèle d'ordre réduit de l'écoulement obtenu par projection de Petrov-Galerkin. La stabilisation d'un écoulement de cavité de type oscillateur est traitée dans une première partie. Il est montré que la totalité de la partie instable de l'écoulement (les modes globaux instables) ainsi que la relation entrée-sortie (action de l'actionneur sur le capteur) de la partie stable doivent être captées par le modèle réduit afin de stabiliser le système. Les modes globaux, modes POD et modes BPOD sont successivement évalués comme bases de projection pour modéliser la partie stable. Les modes globaux ne parviennent pas à reproduire le comportement entrée-sortie de la partie stable et par conséquent ne peuvent stabiliser l'écoulement que lorsque l'instabilité du système est initialement faible (nombre de Reynolds proche de la criticité). En revanche, les modes POD et plus particulièrement BPOD sont capable d'extraire la dynamique entrée-sortie stable et permettent de stabiliser efficacement l'écoulement. La seconde partie de ce travail est consacrée à la réduction de l'amplification des perturbations sur une marche descendante. L'influence de la localisation du capteur et de la fonctionnelle de coût sur la performance du compensateur est étudiée. Il est montré que la troncature du modèle réduit peut rendre le système bouclé instable. Finalement, la possibilité de contrôler une simulation non-linéaire avec un modèle linéaire est évaluée

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Ramirez, Avila Gonzalo. "Synchronization phenomena in light-controlled oscillators." Doctoral thesis, Universite Libre de Bruxelles, 2004. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211169.

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Le but de cette thèse est d'étudier d'une façon expérimentale et théorique le comportement synchrone d'un groupe d'oscillateurs contrôlés par la lumière (LCOs). Ces LCOs sont très simples du point de vue électronique et ont la propriété d'imiter le comportement des lucioles puisqu'ils interagissent par des impulsions de lumière. En même temps, les LCOs sont une bonne approche pour étudier d'autres systèmes qui agissent comme des oscillateurs d'intégration et de tir car un LCO est un oscillateur de relaxation à deux échelles de temps :un long processus de charge alterné avec un très court processus de décharge. Une série d'expériences a été menée pour pouvoir comprendre le processus de synchronisation des LCOs. Nous avons trouvé que l'acquisition de la synchronisation est due aux effets de la perturbation à savoir: le raccourcissement de la charge et l'allongement de la décharge. Les mesures expérimentales ainsi que la physique liée aux LCOs nous ont permis de formuler un modèle qui a été utilisé pour trouver d'une façon analytique la courbe de réponse de phase (PRC) qui caractérise un LCO.

Le modèle a ensuite été validé en comparant les résultats expérimentaux et théoriques. Le modèle reproduit même, le phénomène de bifurcation qui apparaît lorsque trois LCOs sont couplés et disposés en ligne :deux états stables différents apparaissent selon les conditions initiales. L'accord trouvé entre théorie et expérience nous permet d'utiliser le modèle pour étudier d'autres situations qui ne sont pas facilement abordables du point de vue expérimental.

Nous avons étudié analytiquement deux LCOs identiques couplés. Même pour ce cas idéal, nous étions obligés de faire des simplifications pour pouvoir trouver des solutions exactes. On a trouvé pour ce système deux états possibles qui dépendent des conditions initiales, la synchronisation (stable) et l'anti-synchronisation (instable). Nous avons également montré que le temps de synchronisation augmente avec la distance entre LCOs. La construction des langues d'Arnold (régions de synchronisation) nous a permis de distinguer des régions de synchronisation pure d'ordre n:m et des régions de superposition synchronisation--modulation.

Nous avons travaillé numériquement avec des systèmes de LCOs affectés de bruits uniforme et Gaussien. Le comportement synchrone de ce système a été caractérisé en utilisant des paramètres statistiques simples tels que la moyenne de la différence de phase linéaire et la variance de la différence de phase cyclique. Nous avons démontré que le bruit, bien qu'il puisse perturber la synchronisation, peut aussi la favoriser entre deux LCOs qui ne se synchroniseraient pas en conditions normales, surtout quand le bruit est Gaussien et que les variances du bruit ne sont pas égales.

Nous avons étudié en termes statistiques la synchronisation de LCOs couplés localement et arrangés en ligne, en anneau et en réseau. Nous avons montré que la synchronisation totale se produit plus facilement pour des LCOs disposés en anneau. Concernant le temps de synchronisation, il est imprédictible. Les résultats analytiques et numériques suggèrent que la synchronisation totale est le phénomène le plus probable quand le nombre d'oscillateurs n'est pas très grand.

Finalement, nous avons étudié des LCOs statiques et mobiles couplés globalement. Dans les deux cas, nous avons trouvé que la synchronisation est moins probable quand le nombre d'oscillateurs augmente. Pour la condition statique, en considérant un couplage du type champ moyen, nous avons observé que le temps de synchronisation diminue avec le nombre de LCOs. Cependant, pour la situation plus réaliste dans laquelle l'interaction entre LCOs dépend de la distance les séparant, le temps de synchronisation devient à nouveau imprédictible. Enfin, nous avons étudié l'influence de la mobilité sur la synchronisation, problème qui est important en biologie et en robotique.

Notre système, de par ses caractéristiques et sa base expérimentale, est beaucoup plus proche de la réalité que ceux considérés d'habitude dans la littérature. Les résultats obtenus peuvent s'appliquer à des systèmes biologiques (lucioles, cellules cardiaques, neurones, …), mais également à la robotique, où la communication à longue portée par la lumière et l'émergence de patterns de synchronisation pourraient être très utiles dans le but d'effectuer des tâches spécifiques.
Doctorat en sciences, Spécialisation physique
info:eu-repo/semantics/nonPublished

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Parker, Julie. "A study of the phenylacetylene oxidative carbonylation reaction in oscillatory and non-oscillatory modes." Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3281.

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The palladium-catalysed phenylacetylene oxidative carbonylation (PCPOC) reaction operates in both oscillatory and non-oscillatory modes. In oscillatory mode oscillations have been observed in pH, reaction heat (Qr), redox potential and gas uptake. This work documents the steps towards understanding the process and uncovering the reaction mechanism. An extensive experimental study was undertaken involving small-scale (25 mL) experiments on the catalytic system and large-scale (450 mL) experiments on the whole reaction system. The large-scale experiments on the whole system included studies at temperatures from 0-40 °C. The effect of increasing the concentration of water in the system by increasing the solvent volume ratio of water from 0% to 40% was also studied. Decreasing the reaction temperature is known to affect the period and amplitude of the pH oscillations but this work found that it also changes the selectivity of the reaction: the major product is dimethyl (2Z)-2-phenyl-2-butenedioate at 40 °C whereas at 0 °C the major product is 5,5-dimethoxy-3-phenyl-2(5H)-furanone. Increasing the concentration of water in the system affected product selectivity and the oscillatory pH behaviour. As the water concentration increased, pH behaviour changed: the regular shark fin waveform observed when no water was added to the system gradually became step-wise oscillatory behaviour. The small-scale experiments uncovered the link between the mono-carbonylation of phenylacetylene and the generation of H+. They also showed the autocatalytic nature of the reaction between the PdI2 catalyst and carbon monoxide as well as the involvement of water in H+ generation. Based on the experimental findings a tentative model was produced using BatchCAD which accounted for the key features of the observed pH behaviour. The modelling study showed the need for autocatalysis in the model producing the best fit when HI catalysed the reaction between PdI2, CO and H2O.

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Wedgwood, Kyle C. A., Kevin K. Lin, Ruediger Thul, and Stephen Coombes. "Phase-Amplitude Descriptions of Neural Oscillator Models." BioMed Central, 2013. http://hdl.handle.net/10150/610255.

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Phase oscillators are a common starting point for the reduced description of many single neuron models that exhibit a strongly attracting limit cycle. The framework for analysing such models in response to weak perturbations is now particularly well advanced, and has allowed for the development of a theory of weakly connected neural networks. However, the strong-attraction assumption may well not be the natural one for many neural oscillator models. For example, the popular conductance based Morris-Lecar model is known to respond to periodic pulsatile stimulation in a chaotic fashion that cannot be adequately described with a phase reduction. In this paper, we generalise the phase description that allows one to track the evolution of distance from the cycle as well as phase on cycle. We use a classical technique from the theory of ordinary differential equations that makes use of a moving coordinate system to analyse periodic orbits. The subsequent phase-amplitude description is shown to be very well suited to understanding the response of the oscillator to external stimuli (which are not necessarily weak). We consider a number of examples of neural oscillator models, ranging from planar through to high dimensional models, to illustrate the effectiveness of this approach in providing an improvement over the standard phase-reduction technique. As an explicit application of this phase-amplitude framework, we consider in some detail the response of a generic planar model where the strong-attraction assumption does not hold, and examine the response of the system to periodic pulsatile forcing. In addition, we explore how the presence of dynamical shear can lead to a chaotic response.

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Makarau, Amos, and Amos Makarau. "Intra-seasonal oscillatory modes of the southern Africa summer circulation." Doctoral thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/23683.

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Tığrak, Ulaş Esra Pashaev Oktay. "Damping Oscillatory Models In General Theory of Relativity/." [s.l.]: [s.n.], 2007. http://library.iyte.edu.tr/tezler/master/matematik/T000667.pdf.

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Книги з теми "Modes oscillatoire"

The Duffing equation: Nonlinear oscillators and their phenomena. Chichester, West Sussex, U.K: Wiley, 2011.

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Shu, Chi-Wang. Essentially non-oscillatory and weighted essentially non-oscillatory schemes for hyperbolic conservation laws. Hampton, VA: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 1997.

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Pogorzelski, Ronald J. Coupled-oscillator based active-array antennas. Hoboken, New Jersey: John Wiley & Sons Inc., 2012.

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Brown, Catherine Alicia. Oscillatory behavior in an ocean general circulation model of the North Atlantic. Ottawa: National Library of Canada, 1999.

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Waywell, M. N. Predictions of wave and tidally induced oscillatory flows with Reynolds Stress Turbulence Models. Salford: University of Salford, 1995.

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Aldridge, J. N. Comparison of turbulence models for oscillatory rough turbulent boundary layer flows with suspended sediments. Salford: University of Salford Centre for Computational Fluid Dynamics and Turbulence, 1993.

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Osher, Stanley. Essentially non-oscillatory shock capturing methods applied to turbulence amplification in shock wave calculations. [Washington, DC]: National Aeronautics and Space Administration, 1989.

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Bauer, Christopher. Low Reynolds number [kappa]-[epsilon] and empirical transition models for oscillatory pipe flow and heat transfer. [Washington, D.C: National Aeronautics and Space Administration, 1993.

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Sansen, Willy. Analog Circuit Design: (X)DSL and other Communication Systems; RF MOST Models; Integrated Filters and Oscillators. Boston, MA: Springer US, 1999.

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Schütte, Christof. A quasiresonant smoothing algorithm for solving large highly oscillatory differential equations from quantum chemistry. Aachen: Verlag Shaker, 1994.

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Частини книг з теми "Modes oscillatoire"

Garrett, Steven L. "The Simple Harmonic Oscillator." In Understanding Acoustics, 59–131. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-44787-8_2.

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Abstract This chapter will introduce a system that is fundamental to our understanding of more physical phenomena than any other. Although the “simple” harmonic oscillator seems to be only the combination of the most mundane components, the formalism developed to explain the behavior of a mass, spring, and damper is used to describe systems that range in size from atoms to oceans. Our investigation goes beyond the “traditional” treatments found in the elementary physics textbooks. For example, the introduction of damping will open a two-way street: a damping element (i.e., a mechanical resistance, Rm) will dissipate the oscillator’s energy, reducing the amplitudes of successive oscillations, but it will also connect the oscillator to the surrounding environment that will return thermal energy to the oscillator. The excitation of a harmonic oscillator by an externally applied force, displacement, or combination of the two will result in a response that is critically dependent upon the relationship between the frequency of excitation and the natural frequency of the oscillator and will introduce the critical concepts of mechanical impedance, resonance, and quality factor. Finally, the harmonic oscillator model will be extended to coupled oscillators that are represented by combinations of several masses and several springs.

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Santiccioli, Alessio. "Inductorless Frequency Synthesizers for Low-Cost Wireless." In Special Topics in Information Technology, 37–50. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-62476-7_4.

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AbstractThe quest for ubiquitous wireless connectivity, drives an increasing demand for compact and efficient means of frequency generation. Conventional synthesizer options, however, generally trade one requirement for the other, achieving either excellent levels of efficiency by leveraging LC-oscillators, or a very compact area by relying on ring-oscillators. This chapter describes a recently introduced class of inductorless frequency synthesizers, based on the periodic realignment of a ring-oscillator, that have the potential to break this tradeoff. After analyzing their jitter-power product, the conditions that ensure optimum performance are derived and a novel digital-to-time converter range-reduction technique is introduced, to enable low-jitter and low-power fractional-N frequency synthesis. A prototype, which implements the proposed design guidelines and techniques, has been fabricated in 65 nm CMOS. It occupies a core area of 0:0275 mm$$^{2}$$ 2 and covers the 1:6-to-3:0 GHz range, achieving an absolute rms jitter (integrated from 30 kHz-to-30 MHz) of 397 fs at 2:5 mW power. With a corresponding jitter-power figure-of-merit of −244 dB in the fractional-N mode, the prototype outperforms prior state-of-the-art inductorless frequency synthesizers.

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Deych, Lev I. "Harmonic Oscillator Models." In Advanced Undergraduate Quantum Mechanics, 201–54. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-71550-6_7.

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Gazzola, Filippo. "Models with Interacting Oscillators." In Mathematical Models for Suspension Bridges, 149–76. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15434-3_4.

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Olmo, Marta del, Saskia Grabe, and Hanspeter Herzel. "Mathematical Modeling in Circadian Rhythmicity." In Methods in Molecular Biology, 55–80. New York, NY: Springer US, 2021. http://dx.doi.org/10.1007/978-1-0716-2249-0_4.

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AbstractCircadian clocks are autonomous systems able to oscillate in a self-sustained manner in the absence of external cues, although such Zeitgebers are typically present. At the cellular level, the molecular clockwork consists of a complex network of interlocked feedback loops. This chapter discusses self-sustained circadian oscillators in the context of nonlinear dynamics theory. We suggest basic steps that can help in constructing a mathematical model and introduce how self-sustained generations can be modeled using ordinary differential equations. Moreover, we discuss how coupled oscillators synchronize among themselves or entrain to periodic signals. The development of mathematical models over the last years has helped to understand such complex network systems and to highlight the basic building blocks in which oscillating systems are built upon. We argue that, through theoretical predictions, the use of simple models can guide experimental research and is thus suitable to model biological systems qualitatively.

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Rigatos, Gerasimos G. "Oscillatory Dynamics in Biological Neurons." In Advanced Models of Neural Networks, 75–106. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-43764-3_4.

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Mottaghi, Sohrob, Rene Gabbai, and Haym Benaroya. "Lagrangian Flow-Oscillator Models." In An Analytical Mechanics Framework for Flow-Oscillator Modeling of Vortex-Induced Bluff-Body Oscillations, 95–142. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-26133-7_5.

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Mottaghi, Sohrob, Rene Gabbai, and Haym Benaroya. "Eulerian Flow-Oscillator Models." In An Analytical Mechanics Framework for Flow-Oscillator Modeling of Vortex-Induced Bluff-Body Oscillations, 189–240. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-26133-7_7.

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Akhmet, Marat. "Integrate-and-Fire Biological Oscillators." In Nonlinear Hybrid Continuous/Discrete-Time Models, 175–99. Paris: Atlantis Press, 2011. http://dx.doi.org/10.2991/978-94-91216-03-9_10.

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Skinner, Frances K., and Alexandra Pierri Chatzikalymniou. "Oscillatory Dynamics of Brain Microcircuits." In Computational Models of Brain and Behavior, 85–98. Chichester, UK: John Wiley & Sons, Ltd, 2017. http://dx.doi.org/10.1002/9781119159193.ch7.

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Тези доповідей конференцій з теми "Modes oscillatoire"

Chen, Jian, Ganesh Subramanian, Justin Ricci, Liang Ban, and Cetin Cetinkaya. "Non-Contact Mechanical Testing and Characterization of Micro-Scale Structures." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13939.

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A non-contact testing and characterization method based on air-coupled acoustic excitation and interferometric displacement measurements of micro-scale MEMS structures at room conditions is introduced. In demonstrating its potential uses in testing and characterization, the present non-contact approach is applied to (i) micro-cantilever beams and (ii) rotational disk oscillators. Air-coupled multi-mode excitation of micromechanical cantilever-type oscillators under a pulsed acoustic field generated by an air-coupled transducer is demonstrated and reported. Also, the testing and characterization of a micro-scale rotational disk oscillator developed for a new class of sensor platform is demonstrated. The main design objective of the rotational disk oscillator class is to overcome the out-of-plane motion related sensitivity limitations of the cantilever-based sensors at high frequency operations. The dynamics of the rotational disk oscillators is more complex than micro-cantilever beams due to its in-plane motion in addition to its various out-of-plane modes of vibration. The fabrication of a rotational disk oscillator requires a suspended disk whose underside is visibly inaccessible due to a narrow micro-gap. In addition to the dynamic characterization of the cantilever beams and rotational disk oscillators, the current investigation demonstrates that the presented approach can address unique structural concerns such as the verification of a gap separation of the rotational oscillator from the underlying silicon substrate. Utilizing the proposed technique, the resonant frequencies of the oscillator structures are obtained and its potential uses in the testing and characterization of micro-scale structures are discussed. The major specific advantages of the introduced approach include that (i) its noncontact nature can eliminate testing problems associated with stiction and adhesion, and (ii) it allows direct mechanical characterization and testing of components and sub-components of a micro-scale devices.

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Khoshnoud, Farbod, Houman Owhadi, and Clarence W. de Silva. "Stochastic Simulation of a Casimir Oscillator." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39746.

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Stochastic simulation of a Casimir Oscillator is presented in this paper. This oscillator is composed of a flat boundary of semiconducting oscillator parallel to a fixed plate separated by vacuum. In this system the oscillating surface is attracted to the fixed plate by the Casimir effect, due to quantum fluctuations in the zero point electromagnetic field. Motion of the oscillating boundary is opposed by a spring. The stored potential energy in the spring is converted into kinetic energy when the spring force exceeds the Casimir force, which generates an oscillatory motion of the moving plate. Casimir Oscillators are used as micro-mechanical switches, sensors and actuators. In the present paper, a stochastic simulation of a Casimir oscillator is presented for the first time. In this simulation, Stochastic Variational Integrators using a Langevin equation, which describes Brownian motion, is considered. Formulations for Symplectic Euler, Constrained Symplectic Euler, Stormer-Verlet and RATTLE integrators are obtained and the Symplectic Euler case is solved numerically. When the moving parts in a micro/nano system travel in the vicinity of 10 nanometers to 1 micrometer range relative to other parts of the system, the Casimir phenomenon is in effect and should be considered in analysis and design of such system. The simulation in this paper considers modeling such uncertainties as friction, effect of surface roughness on the Casimir force, and change in environmental conditions such as ambient temperature. In this manner the paper explores a realistic model of the Casimir Oscillator. Furthermore, the presented study of this system provides a deeper understanding of the nature of the Casimir force.

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Taniguchi, Tomoyo, Yoshihiko Toda, Yusuke Ono, and Kyosuke Mukaibo. "Estimation Accuracy of Absolute Maximum Elasto-Plastic Displacements of MDOF Oscillators Based on a Modal Combination Rule With Post-Yielding Modal Properties and Linear Response Spectrum Values." In ASME 2018 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/pvp2018-84237.

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Taniguchi, et al. [1] developed an analytical method for evaluating the absolute maximum elasto-plastic displacements of multi-degree-of-freedom (MDOF) oscillators under the action of base excitation based on a modal combination. Its essence is that 1) modal frequencies, shapes and damping during yielding of any member of the MDOF oscillators are readily specified by the modal analysis with the secondary stiffness of the members being yielded, 2) assuming that a bilinear hysteresis may describe the force-displacement relationship of each mode, an equivalently linearized system consisting of a single-degree-of-freedom (SDOF) oscillator is introduced to approximate the absolute maximum elasto-plastic displacement of each mode, 3) the absolute maximum elasto-plastic displacement of the MDOF oscillator is evaluated by the Square Root of Sum of Squares rule (SRSS-rule) by combining the maximum elasto-plastic displacement of each mode approximated by the proposed equivalently linearized system. This study first provides small modification in the equivalently linearized system. Then, employing a couple of MDOF oscillators whose spring at arbitrary storey may yield and an accelerogram, the maximum elasto-plastic displacement of the MDOF oscillator is calculated by the proposed method and is compared with that computed by the time history analysis. Their comparison suggests that the proposed method can reasonably evaluate the absolute maximum elasto-plastic displacement of the MDOF oscillator subjected to earthquake excitation as the conventional SRSS-rule does that for the linear MDOF oscillators.

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Rompala, Kevin, Richard Rand, and Howard Howland. "Dynamics of Three Coupled Van der Pol Oscillators With Application to Circadian Rhythms." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84017.

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In this work we study a system of three van der Pol oscillators, x, y and w, coupled as follows: x¨−ε(1−x2)x˙+x=εμ(w−x)y¨−ε(1−y2)y˙+y=εμ(w−y)w¨−ε(1−w2)w˙+p2w=εμ(x−w)+εμ(y−w) Here the x and y oscillators are identical, and are not directly coupled to each other, but rather are coupled via the w oscillator. We investigate the existence of the in-phase mode x = y for ε ≪ 1. To this end we use the two variable expansion perturbation method (also known as multiple scales) to obtain a slow flow, which we then analyze using the software products MACSYMA and AUTO. Our motivation for studying this system comes from the presence of circadian rhythms in the chemistry of the eyes. We model the circadian oscillator in each eye as a van der Pol oscillator (x and y). Although there is no direct connection between the two eyes, they are both connected to the brain, especially to the pineal gland, which is here represented by a third van der Pol oscillator (w).

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Storti, Duane W., Cornelius Nevrinceanu, and Per G. Reinhall. "Perturbation Solution of an Oscillator With Periodic van der Pol Damping." In ASME 1993 Design Technical Conferences. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/detc1993-0128.

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Abstract We present a perturbation solution for a linear oscillator with a variable damping coefficient involving the limit cycle of the van der Pol equation (van der Pol 1926). This equation arises as the variational equation governing the stability of in-phase vibration in a pair of identical van der Pol oscillators with linear coupling. The van der Pol oscillator has served as the classic example of a limit cycle oscillator, and coupled limit cycle oscillators appear in mathematical models of self-excited systems ranging from tube rows in cross flow heat exchangers to arrays of stomates in plant leaves. As in many systems modeled by coupled oscillators, criteria for phase-locking or synchronization are of fundamental importance in understanding the dynamics. In this paper we study a simple but interesting problem consisting of a pair of identical van der Pol oscillators with linear diffusive coupling which corresponds, in the mechanical analogy, to a spring connecting the masses of the two oscillators. Intuition and earlier first-order analyses suggest that the spring will pull the two masses together causing stable in-phase locking. However, previous results of a relaxation limit study (Storti and Rand 1986) indicate that the in-phase mode is not always stable and suggest the existence of an additional stability boundary. To resolve the apparent discrepancy, we obtain a new periodic solution of the variational equation as a power series in ε, the small parameter in the sinusoidal van de Pol oscillator. This approach follows Andersen and Geer’s (1982) solution for the limit cycle of an isolated van der Pol oscillator. The coupling strength corresponding to the periodic solution of the variational equation defines an additional stability transition curve which has only been observed previously in the relaxation limit. We show that this transition curve, which provides a consistent connection between the sinusoidal and relaxation limits, is O(ε2) and could not have been delected in O(ε) analyses. We determine the analytical expression for this stability transition curve to O(ε31) and show very favorable agreement with numerical results we obtained using an Adams-Gear method.

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Camacho, Erika, Richard Rand, and Howard Howland. "Dynamics of Two Van Der Pol Oscillators Coupled via a Bath." In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/vib-48593.

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In this work we study a system of two van der Pol oscillators, x and y, coupled via a “bath” z: x¨−ε(1−x2)x˙+x=k(z−x)y¨−ε(1−y2)y˙+y=k(z−y)z˙=k(x−z)+k(y−z) We investigate the existence and stability of the in-phase and out-of-phase modes for parameters ε > 0 and k > 0. To this end we use Floquet theory and numerical integration. Surprisingly, our results show that the out-of-phase mode exists and is stable for a wider range of parameters than is the in-phase mode. This behavior is compared to that of two directly coupled van der Pol oscillators, and it is shown that the effect of the bath is to reduce the stability of the in-phase mode. We also investigate the occurrence of other periodic motions by using bifurcation theory and the AUTO bifurcation and continuation software package. Our motivation for studying this system comes from the presence of circadian rhythms in the chemistry of the eyes. We present a simplified model of a circadian oscillator which shows that it can be modeled as a van der Pol oscillator. Although there is no direct connection between the two eyes, they can influence each other by affecting the concentration of melatonin in the bloodstream, which is represented by the bath in our model.

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Taniguchi, Tomoyo, Hiroki Nishiraku, and Yusuke Ono. "Analysis of Maximum Elasto-Plastic Response of Multi-Degree-of-Freedom Oscillators Based on a Modal Combination of Equivalently Linearized Response of Each Mode." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63865.

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This study develops a new analytical method for evaluating maximum elasto-plastic displacement of multi-degree-of-freedom (MDOF) oscillators under the action of base excitation based on a modal combination. The essence is that modal frequencies, shapes and damping during yielding of any member of the MDOF oscillators are readily specified by the modal analysis with the secondary stiffness of the members being yielded. In addition, assuming that a bilinear hysteresis may describe the force-displacement relationship of each mode, an equivalently linearized system consisting of a single-degree-of-freedom (SDOF) oscillator is introduced to approximate maximum elsato-plastic displacement of each mode. Employing the SRSS-rule, the maximum elasto-plastic displacement of the MDOF oscillator subjected to Kobe-NS accelerogram is calculated and compared with that computed by the commercial software. Applicability of the proposed method to evaluating maximum elasto-plastic displacement of the MDOF oscillator is thoroughly discussed.

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Haaker, T. I. "Analysis of a Class of Coupled Nonlinear Oscillators With an Application to Flow Induced Vibrations." In ASME 2001 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/detc2001/vib-21416.

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Abstract We consider in this paper the following system of coupled nonlinear oscillatorsx..+x-k(y-x)=εf(x,x.),y..+(1+δ)y-k(x-y)=εf(y,y.). In this system we assume ε to be a small parameter, i.e. 0 < ε ≪ 1. A coupling between the two oscillators is established through the terms involving the positive parameter k. The coupling may be interpreted as a mutual force depending on the relative positions of the two oscillators. For both ε and k equal to zero the two oscillators are decoupled and behave as harmonic oscillators with frequencies 1 and 1+δ, respectively. The parameter δ may therefore be viewed as a detuning parameter. Finally, the term ε f represents a small force acting upon each oscillator. Note that this force depends only on the position and velocity of the oscillator upon which the force is acting. To analyse the system’s dynamic behaviour we use the method of averaging. When k and δ are choosen such that no internal resonance occurs, one typically observes the following behaviour. If the trivial solution is unstable, solutions asymptotically tend to one of the two normal modes or to a mixed mode solution. For the special case with δ = 0 a system of two identical oscillators is found. If in addition k is O(ε) we obtain a 1 : 1 internal resonant system. The averaged equations may then be reduced to a system of three coupled equations — two for the amplitudes and one for the phase difference. Due to the fact that we consider identical oscillators there is a symmetry in the averaged equations. The normal mode solutions, as found for the non-resonant case, are still present. New mixed mode solutions appear. Moreover, Hopf bifurcations in the averaged system lead to limit cycles that correspond to oscillations in the original system with periodically modulated amplitudes and phases. We also consider the case with δ = O(ε), i.e. the case with nearly identical oscillators. If k = O(ε) again a 1 : 1 internal resonant system is found. Contrary to the previous cases the normal mode solutions no longer exist. Moreover, different bifurcations are observed due to the disappearance of the symmetry present in the system for s = 0. We apply some of the results obtained to a model describing aeroelastic oscillations of a structure with two-degrees-of-freedom.

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Li, Wei, Gen-xiang Chen, Xun Li, and Wei-ping Huang. "Active Mode Locking: Quantum Oscillator vs. Classical Coupled Oscillators." In 2006 IEEE International Conference on Electro/Information Technology. IEEE, 2006. http://dx.doi.org/10.1109/eit.2006.252106.

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Ghorbanian, Parham, Subramanian Ramakrishnan, and Hashem Ashrafiuon. "EEG Stochastic Nonlinear Oscillator Models for Alzheimer’s Disease." In ASME 2015 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/dscc2015-9676.

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In this article, we derive unique stochastic nonlinear coupled oscillator models of EEG signals from an Alzheimer’s Disease (AD) study. EEG signals recorded during resting eyes-open (EO) and eyes-closed (EC) conditions in a pilot study with AD patients and age-matched healthy control subjects (CTL) are employed. An optimization scheme is then utilized to match the output of the stochastic Duffing - van der Pol double oscillator network with EEG signals recorded during each condition for AD and CTL subjects. The selected decision variable are the model parameters and noise intensity. While, the selected signal characteristics are power spectral densities in major brain frequency bands and Shannon and sample entropies to match the signal information content and complexity. It is shown that statistically significant unique models represent the EC and EO conditions for both CTL and AD subjects. Moreover, the inclusion of sample entropy in the optimization process significantly enhances the stochastic nonlinear oscillator model performance. The study suggests that EEG signals recorded under different brain states as well as those belonging to a brain disorder such as Alzheimer’s disease can be uniquely represented by stochastic nonlinear oscillators paving the way for identification of new discriminants.

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Звіти організацій з теми "Modes oscillatoire"

Slawianowski, Jan J., and Agnieszka Martens Martens. Affinely-Rigid Body and Oscillatory Two-Dimensional Models. GIQ, 2015. http://dx.doi.org/10.7546/giq-16-2015-94-109.

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Ng, Leslie, Richard H. Rand, Timothy Wei, and William L. Keith. An Examination of Wake Oscillator Models for Vortex-Induced Vibrations. Fort Belvoir, VA: Defense Technical Information Center, August 2001. http://dx.doi.org/10.21236/ada390553.

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Kimberland, S. Burst mode Nd:YLF laser oscillator: Eighth and final monthly progress report. Office of Scientific and Technical Information (OSTI), March 1987. http://dx.doi.org/10.2172/5643030.

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Weaver, David R. Development and Validation of a Computational Model for Intra-Cellular Circadian Oscillators. Fort Belvoir, VA: Defense Technical Information Center, May 2005. http://dx.doi.org/10.21236/ada435444.

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Himmel, Jeffrey, John Gualtieri, and John Kosinski. Acceleration Sensitivity and Mode Shape Relationship Tests of Voltage Controlled Surface Acoustic Wave Oscillator. Fort Belvoir, VA: Defense Technical Information Center, August 1995. http://dx.doi.org/10.21236/ada299044.

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Dawson, J., M. Messerly, and J. An. Fiber Laser Replacement for Short Pulse Ti:Sapphire Oscillators -- Scalable Mode Locking to Record Pulse Energies. Office of Scientific and Technical Information (OSTI), February 2006. http://dx.doi.org/10.2172/889996.

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Nobile, F., Q. Ayoul-Guilmard, S. Ganesh, M. Nuñez, A. Kodakkal, C. Soriano, and R. Rossi. D6.5 Report on stochastic optimisation for wind engineering. Scipedia, 2022. http://dx.doi.org/10.23967/exaqute.2022.3.04.

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This report presents the latest methods of optimisation under uncertainties investigated in the ExaQUte project, and their applications to problems related to civil and wind engineering. The measure of risk throughout the report is the conditional value at risk. First, the reference method is presented: the derivation of sensitivities of the risk measure; their accurate computation; and lastly, a practical optimisation algorithm with adaptive statistical estimation. Second, this method is directly applied to a nonlinear relaxation oscillator (FitzHugh–Nagumo model) with numerical experiments to demonstrate its performance. Third, the optimisation method is adapted to the shape optimisation of an airfoil and illustrated by a large-scale experiment on a computing cluster. Finally, the benchmark of the shape optimisation of a tall building under a turbulent flow is presented, followed by an adaptation of the optimisation method. All numerical experiments showcase the open-source software stack of the ExaQUte project for large-scale computing in a distributed environment.

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Thornell, Travis, Charles Weiss, Sarah Williams, Jennifer Jefcoat, Zackery McClelland, Todd Rushing, and Robert Moser. Magnetorheological composite materials (MRCMs) for instant and adaptable structural control. Engineer Research and Development Center (U.S.), November 2020. http://dx.doi.org/10.21079/11681/38721.

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Magnetic responsive materials can be used in a variety of applications. For structural applications, the ability to create tunable moduli from relatively soft materials with applied electromagnetic stimuli can be advantageous for light-weight protection. This study investigated magnetorheological composite materials involving carbonyl iron particles (CIP) embedded into two different systems. The first material system was a model cementitious system of CIP and kaolinite clay dispersed in mineral oil. The magnetorheological behaviors were investigated by using parallel plates with an attached magnetic accessory to evaluate deformations up to 1 T. The yield stress of these slurries was measured by using rotational and oscillatory experiments and was found to be controllable based on CIP loading and magnetic field strength with yield stresses ranging from 10 to 104 Pa. The second material system utilized a polystyrene-butadiene rubber solvent-cast films with CIP embedded. The flexible matrix can stiffen and become rigid when an external field is applied. For CIP loadings of 8% and 17% vol %, the storage modulus response for each loading stiffened by 22% and 74%, respectively.

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Schilling, O., and M. Latini. Weighted Essentially Non-Oscillatory Simulations and Modeling of Complex Hydrodynamic Flows. Part 2. Single-Mode Richtmyer-Meshkov Instability with Reshock. Office of Scientific and Technical Information (OSTI), October 2004. http://dx.doi.org/10.2172/15014825.

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Latini, M., and O. Schilling. Weighted Essentially Non-Oscillatory Simulations and Modeling of Complex Hydrodynamic Flows. Part 2. Single-Mode Richtmyer-Meshkov Instability with Reshock. Office of Scientific and Technical Information (OSTI), April 2005. http://dx.doi.org/10.2172/15016331.

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