Academic literature on the topic 'Partial synchronization'

In this Letter we analyze the concept of partial synchronization as observer design. Our aim is to estimate a signal, the function of the coordinates of a particular system that, when considering a specific output, is not necessarily fully observable.

In this paper, we report the phenomena of global and partial phase synchronizations in linear arrays of unidirectionally coupled piecewise linear time-delay systems. In particular, in a linear array with open end boundary conditions, global phase synchronization (GPS) is achieved by a sequential synchronization of local oscillators in the array as a function of the coupling strength (a second order transition). Several phase synchronized clusters are also formed during the transition to GPS at intermediate values of the coupling strength, as a prelude to full scale synchronization. On the other hand, in a linear array with closed end boundary conditions (ring topology), partial phase synchronization (PPS) is achieved by forming different groups of phase synchronized clusters above some threshold value of the coupling strength (a first order transition) where they continue to be in a stable PPS state. We confirm the occurrence of both global and partial phase synchronizations in two different piecewise linear time-delay systems using various qualitative and quantitative measures in three different frameworks, namely, using explicit phase, recurrence quantification analysis and the framework of localized sets.

In this paper, the analytical conditions for the controlled pendulum synchronizing with periodic motions in the Duffing oscillator are developed using the theory of discontinuous dynamical systems. From the analytical conditions, the synchronization invariant domain is obtained. The partial and full synchronizations of the controlled pendulum with periodic motions in the Duffing oscillator are discussed. The control parameter map for the synchronization is achieved from the analytical conditions, and numerical illustrations of the partial and full synchronizations are carried out to illustrate the analytical conditions. This synchronization is different from the controlled Duffing oscillator synchronizing with chaotic motion in the periodically excited pendulum. Because the periodically forced, damped Duffing oscillator possesses periodic and chaotic motions, further investigation on the controlled pendulum synchronizing with complicated periodic and chaotic motions in the Duffing oscillator will be accomplished in sequel.

This paper discusses the synchronization of the Van der Pol equation with a pendulum under the sinusoidal constraint through the theory of discontinuous dynamical systems. The analytical conditions for the sinusoidal synchronization of the Van der Pol equation with a periodically forced pendulum are developed. With the conditions, the sinusoidal synchronizations of the two systems are discussed. Switching points for appearance and vanishing of the partial synchronization are developed.

Partial synchronization in Hamiltonian systems is investigated based on the concept of measure-synchronization. The classical φ4 model is used for the investigation. A macroscopic observable of long-term average of particle energy is computed to describe transitions between desynchronization, different partial synchronization, and complete synchronization structures. It is found that, prior to the entire synchronization of all oscillators, partial measure-synchronization for some clusters of oscillators is stable within certain regions. Moreover, transition from quasiperiodicity to chaos is observed to be associated with the measure-synchronization as the coupling strength is increased.

In this paper, the dynamics mechanism of the projective synchronization of Chua circuits with different scrolls is investigated analytically through the theory of discontinuous dynamical systems. The analytical conditions for the projective synchronization of Chua circuits with chaotic motions are developed. From these conditions, the parameter characteristics of the projective synchronization of Chua circuits with different scrolls are discussed, and the corresponding parameter maps and the invariant domain for such projective synchronization of Chua circuits are presented. Illustrations for partial and full projective synchronizations of the Chua circuits are given. The projective synchronization of Chua circuits is implemented experimentally, and numerical and experimental results are compared.

For the partial synchronization problem in integration of workflow process model with data model, this paper develops an algorithm through synchronization edges to get synchronization processes. Firstly, a workflow model called RTWD net is introduced. Then the concepts of synchronization edge, process, synchronization process, base process, process tree, data type and trace-set of types is given. Finally, an algorithm for abstracting the synchronization process and a case study is presented.

Published Article
A reference carrier signal should be regenerated from a received partial response (PR) signal in order to facilitate optimal demodulation of the received signal. This paper describes the development and evaluation of such a carrier recovery system using DSP techniques. The relative phase of a free-running local oscillator at the receiver is synchronized with the carrier signal of a received 49 quadrature partial response signal (49QPRS). Synchronization is achieved and maintained by means of a process of cross-correlation.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (p. 121-128).
This thesis focuses on the study of collective dynamic behaviors, especially the spontaneous synchronization behavior, of nonlinear networked systems. We derives a body of new results, based on contraction and partial contraction analysis. Contraction is a property regarding the convergence between two arbitrary system trajectories. A nonlinear dynamic system is called contracting if initial conditions or temporary disturbances are forgotten exponentially fast. Partial contraction, introduced in this thesis, is a straightforward but more general application of contraction. It extends contraction analysis to include convergence to behaviors or to specific properties (such as equality of state components, or convergence to a manifold). Contraction and partial contraction provide powerful analysis tools to investigate the stability of large-scale complex systems. For diffusively coupled nonlinear systems, for instance, a general synchronization condition can be derived which connects synchronization rate to net- work structure explicitly. The results are applied to construct flocking or schooling models by extending to coupled networks with switching topology. We further study the networked systems with different kinds of group leaders, one specifying global orientation (power leader), another holding target dynamics (knowledge leader). In a knowledge-based leader-followers network, the followers obtain dynamics information from the leader through adaptive learning. We also study distributed networks with non-negligible time-delays by using simplified wave variables and other contraction-oriented analysis. Conditions for contraction to be preserved regardless of the explicit values of the time-delays are derived.
(cont.) Synchronization behavior is shown to be robust if the protocol is linear. Finally, we study the construction of spike-based neural network models, and the development of simple mechanisms for fast inhibition and de-synchronization.
by Wei Wang.
Ph.D.

Assisted partial timing support is a method to enhance the synchronization of communication networks based on the Precision Timing Protocol. One of the main benefits of the Precision Timing Protocol is that it can utilize a method called holdover through which synchronization in communication networks can be maintained, however, holdover is easily impacted by network load which may cause it to deviate from a microsecond accuracy that is required. In this project, neural networks are investigated as an aid to assisted partial timing support with the intention to combat the effects of network load. This hypothesis is to achieve this through a neural network being able to predict the offset due to time delay in the communication networks and thus being able to cancel out this effect from previous offset. Feed-forward and recurrent neural networks are tested on four different types of load patterns that commonly occur on communication networks. The results show that although some level of prediction is possible, the accuracy with which the tested neural networks provide prediction is not high enough to allow it to be used for compensation of the offset caused by the load. This with the best result reaching a mean squared error of ten microseconds squared and the requirement looked for was for where the maximum was one microsecond. This project only looked at short periods of the load patterns and future areas to investigate could be looking at longer periods of the load patterns.

Orthostatic intolerance (OI), i.e., the inability to maintain stable arterial pressure during upright posture, is a major problem for astronauts after spaceflight. Therefore, one important goal of spaceflight-related research is the development of countermeasures to prevent post flight OI. Given the rarity and expense of spaceflight, countermeasure development requires ground-based simulations of partial gravity to induce appropriate orthostatic effects on the human body, and to test the efficacy of potential countermeasures. To test the efficacy of upright lower body positive pressure (LBPP) as a model for simulating cardiovascular responses to lunar and Martian gravities on Earth, cardiovascular responses to upright LBPP were compared with those of head-up tilt (HUT), a well-accepted simulation of partial gravity, in both ambulatory and cardiovascularly deconditioned subjects. Results indicate that upright LBPP and HUT induced similar changes in cardiovascular regulation, supporting the use of upright LBPP as a potential model for simulating cardiovascular responses to standing and moving in lunar and Martian gravities. To test the efficacy of a short exposure to artificial gravity (AG) as a countermeasure to spaceflight-induced OI, orthostatic tolerance limits (OTL) and cardiovascular responses to orthostatic stress were tested in cardiovascularly deconditioned subjects, using combined 70º head-up tilt and progressively increased lower body negative pressure, once following 90 minutes AG exposure and once following 90 minutes of -6º head-down bed rest (HDBR). Results indicate that a short AG exposure increased OTL of cardiovascularly deconditioned subjects, with increased baroreflex and sympathetic responsiveness, compared to those measured after HDBR exposure. To gain more insight into mechanisms of causal connectivity in cardiovascular and cardiorespiratory oscillations during orthostatic challenge in both ambulatory and cardiovascularly deconditioned subjects, couplings among R-R intervals (RRI), systolic blood pressure (SBP) and respiratory oscillations in response to graded HUT and dehydration were studied using a phase synchronization approach. Results indicate that increasing orthostatic stress disassociated interactions among RRI, SBP and respiration, and that dehydration exacerbated the disconnection. The loss of causality from SBP to RRI following dehydration suggests that dehydration also reduced involvement of baroreflex regulation, which may contribute to the increased occurrence of OI.

De nombreux systèmes de transport peuvent être modélisées par des synchronisations ordinaires (pour tout k>=l, l'occurrence k de l'événement B se produit au moins t unités de temps après l'occurrence k-l de l'événement A). Ces systèmes sont linéaires dans l'algèbre (max,+). Pour certaines applications, il est primordial de modéliser la simultanéité entre événements. Comme la synchronisation ordinaire ne suffit pas à exprimer ce phénomène, nous introduisons la synchronisation partielle (l'événement B ne peut se produire que quand l'événement A se produit). Dans ce mémoire, des méthodes développées pour la modélisation et le contrôle de systèmes linéaires dans l'algèbre (max,+) sont étendues à des systèmes régis par des synchronisations ordinaires et partielles. Nous considérons uniquement des systèmes divisés en un système principal et un système secondaire et gouvernés par des synchronisations ordinaires entre événements dans le même système et des synchronisations partielles d'événements dans le système secondaire par des événements dans le système principal. Nous introduisons une commande optimale et une commande prédictive pour cette classe de systèmes par analogie avec les résultats disponibles pour les systèmes linéaires dans l'algèbre (max,+). En considérant un comportement donné pour le système principal, il est aussi possible de représenter le système secondaire par une fonction de transfert et de modifier sa dynamique pour suivre un modèle de référence
Many transportation networks can be modeled by (max,+)-linear systems, i.e., discrete event systems ruled by standard synchronizations (conditions of the form: "for all k>=l, occurrence k of event B is at least t units of time after occurrence k-l of event A"). In some applications, it is also necessary to model simultaneity between events (e.g., for a road equipped with traffic lights, a vehicle can cross an intersection only when the associated traffic light is green). Such conditions cannot be expressed using standard synchronizations. Hence, we introduce the partial synchronization (condition of the form: "event B can only occur when event A occurs"). In this thesis, we consider a class of discrete event systems ruled by standard and partial synchronizations, called (max,+)-systems with partial synchronization. Such systems are split into a main system and a secondary system such that there exist only standard synchronizations between events in the same system and partial synchronizations of events in the secondary system by events in the main system. We adapt some modeling and control approaches developed for (max,+)-linear systems to (max,+)-systems with partial synchronization. Optimal feedforward control and model predictive control for (max,+)-linear systems are extended to (max,+)-systems with partial synchronization. Furthermore, transfer relation and model reference control are provided for the secondary system under a predefined behavior of the main system

Dissertação de Mestrado Integrado em Medicina Veterinária
Para uma empresa agrícola é importante avaliar o impacto económico de uma nova tecnologia antes de ser implementada, nomeadamente a sincronização de partos. Neste contexto foi avaliado o custo-benefício de um protocolo de sincronização utilizando 0,175 mg cloprostenol e 40 UI de oxitocina por animal, tendo sido adotados como parâmetros de avaliação de eficiência reprodutiva a proporção de partos que decorreram durante o horário laboral, o peso dos leitões ao nascimento, o número de nados vivos, o número de nados mortos, a mortalidade acumulada às 48h, o número de leitões desmamados e o peso dos leitões ao desmame. A amostra foi constituida por 100 porcas F1, com mais de um parto, divididas em dois grupos. No grupo de tratamento o parto foi induzido, enquanto que no grupo controlo a parição foi espontânea. Dos parâmetros em estudo, o único que resultou numa diferença estatisticamente significativa entre os grupos em estudo foi o peso ao nascimento. A média do peso do grupo de controlo foi de 1252,96 +/- 330,04g, enquanto que a média do peso no grupo de tratamento foi de 1227,90 +/- 378,58g. A proporção de partos que ocorreram durante o horário laboral no grupo de tratamento foi de 81%, enquanto que o no grupo de tratamento 35% dos partos ocorreram durante o horário laboral. Utilizou-se a metodologia dos orçamentos parciais de substituição para analisar a viabilidade económica da sincronização de partos em porcas face a uma situação de partos não induzidos. Esta sincronização tem viabilidade económica (2. 545,4 EUR/ano para a exploração) se após indução, os partos ocorrerem em apenas um dia, mas não terá viabilidade se estes ocorrerem num período de dois dias (-58,8 EUR/ano para a exploração).
ABSTRACT - For an agricultural business, it is important to evaluate the economic impact of a new technology before its implementation, namely parturition synchronization. In this context, it was evaluated the benefit of a synchronization protocol using 0,175 mg of cloprostenol and 40 UI of oxytocin per animal, having as efficiency parameters the percentage of births occurring during work hours, piglet birth weight, number of stillbirths, number of born alive, cumulative mortality at 48h, number of weaned piglets and their weight. The sample was composed of 100 F1 sows, all with more than one parturition, and wasdivided into two groups: the treatment group, where birth was induced, and a control group where the sows were left to birth spontaneously. The only parameter in the study that resulted in a significantly statistical difference was the piglet birth weight, where the control group weight 1252,96 +/- 330,04g, and the treatment group 1227,90 +/- 378,58g. The percentage of births occurring during work hours in the treatment group was 81% whereas in the control group that percentage was 35%. Partial budgeting analysis was used to assess the economic benefit of a parturition synchronization protocol in sows. If delivers occurs in two days after induction, the net result is expected to be -58,8 EUR/year for the farm whereas if delivers occurs in only one day after induction, the net result is expected to be 2. 545,4 EUR/year for the farm.
info:eu-repo/semantics/publishedVersion

Le fonctionnement d'un neurone, unité fondamentale du système nerveux, intéresse de nombreuses disciplines scientifiques. Il existe ainsi des modèles mathématiques qui décrivent leur comportement par des systèmes d'EDO ou d'EDP. Plusieurs de ces modèles peuvent ensuite être couplés afin de pouvoir étudier le comportement de réseaux, systèmes complexes au sein desquels émergent des propriétés. Ce travail présente, dans un premier temps, les principaux mécanismes régissant ce fonctionnement pour en comprendre la modélisation. Plusieurs modèles sont alors présentés, jusqu'à celui de FitzHugh-Nagumo (FHN), qui présente une dynamique très intéressante.C'est sur l'étude théorique mais également numérique de la dynamique asymptotique et transitoire du modèle de FHN en EDO, que se concentre la seconde partie de cette thèse. A partir de cette étude, des réseaux d'interactions d'EDO sont construits en couplant les systèmes dynamiques précédemment étudiés. L'étude du phénomène de synchronisation identique au sein de ces réseaux montre l'existence de propriétés émergentes pouvant être caractérisées par exemple par des lois de puissance. Dans une troisième partie, on se concentre sur l'étude du système de FHN dans sa version EDP. Comme la partie précédente, des réseaux d'interactions d'EDP sont étudiés. On entreprend dans cette partie une étude théorique et numérique. Dans la partie théorique, on montre l'existence de l'attracteur global dans l'espace L2(Ω)nd et on donne des conditions suffisantes de synchronisation. Dans la partie numérique, on illustre le phénomène de synchronisation ainsi que l'émergence de lois générales telles que les lois puissances ou encore la formation de patterns, et on étudie l'effet de l'ajout de la dimension spatiale sur la synchronisation
The neuron, a fundamental unit in the nervous system, is a point of interest in many scientific disciplines. Thus, there are some mathematical models that describe their behavior by ODE or PDE systems. Many of these models can then be coupled in order to study the behavior of networks, complex systems in which the properties emerge. Firstly, this work presents the main mechanisms governing the neuron behaviour in order to understand the different models. Several models are then presented, including the FitzHugh-Nagumo one, which has a interesting dynamic. The theoretical and numerical study of the asymptotic and transitory dynamics of the aforementioned model is then proposed in the second part of this thesis. From this study, the interaction networks of ODE are built by coupling previously dynamic systems. The study of identical synchronization phenomenon in these networks shows the existence of emergent properties that can be characterized by power laws. In the third part, we focus on the study of the PDE system of FHN. As the previous part, the interaction networks of PDE are studied. We have in this section a theoretical and numerical study. In the theoretical part, we show the existence of the global attractor on the space L2(Ω)nd and give the sufficient conditions for identical synchronization. In the numerical part, we illustrate the synchronization phenomenon, also the general laws of emergence such as the power laws or the patterns formation. The diffusion effect on the synchronization is studied

In this Ph.D. thesis, a new methodology for the fault tolerant system state synchronization design and its recovery from faults is presented. A state synchronization method designed by means of the proposed methodology allows to repair the state of sequential logic elements implemented in the FPGA application logic, which cannot be repaired by the partial dynamic reconfiguration. The proposed methodology describes possible state synchronization design methods with respect to TMR granularity, dependence of the system function on its previous states and the system architecture. The methodology focuses on coarse-grained TMR architectures and state synchronization in the systems controlled by means of finite state machines or a processor. The use of the methodology is demonstrated on the CAN bus control system and the microcontroller NEO430, for which specific synchronization methods were designed. The systems reliability and new ability of the systems for recovery from faults were verified in the presence of simulated SEU faults. The experimental results and the contribution of this thesis are discussed in the conclusion.

In Particle Accelerators, the Low-Level RF (LLRF) is the control system of the RF, and in the end, of the purpose of the machine, that is the energy transfer and acceleration of particles. It implements algorithms synchronizing the RF conveying the energy to the beam and tailoring its longitudinal parameters. For this, the LLRF uses beam-related signals whose spectral content changes during the acceleration. The increase in energy results in an increase of the beam velocity, and for circular accelerators (Synchrotrons) a decrease in revolution period. This is especially relevant for Hadron machines whose injection energy is low resulting in a significant increase of their velocity before reaching relativistic speeds. Hence, the LLRF needs to continuously tune its processing to the beam; we call this technique Beam Synchronous Processing. One important task of the LLRF is the compensation of the beam-induced voltage in the accelerating cavities (Beam Loading). In the CERN SPS the regulation bandwidth must cover 5 MHz on each side of the 200 MHz RF. With a beam revolution period around 23 µs more than a hundred revolution frequency harmonics, present in the beam signal, fall in the RF sidebands. The variation in beam velocity changes the position and spacing of the harmonics in the spectrum. The large number of harmonics and their varying positions make the algorithm reconfiguration an undesirable option. To cope with this, the early digital implementations used a system clock derived from the sweeping RF. This locks the sampling and the processing to the beam, by design. This historical solution, that is still in use in several machines, is now a limiting factor for the use of modern technologies. The Thesis presents a novel Beam Synchronous Processing Architecture, using a fixed frequency clocking, and capable of treating periodic signals with known and varying fundamental frequency. The Architecture is an alternative to the burden of reconfiguration in processing algorithms; it tunes the spectrum to the processing by resampling the input data. Two Resamplers are combined in the so-called resampling sandwich. The application algorithm requiring synchronism with the input signal is placed in the middle. The key element is a novel All-Digital Farrow-based Resampler, that accepts arbitrary resampling ratios that can be modified in real-time. The hardware uses a single fixed frequency system clock, making its implementation feasible in State-Of-the-Art FPGAs, ASICs and systems such as the new uTCA platform currently being deployed in the CERN SPS LLRF system. The input and output ports of the Resampler, and all the processing within the Architecture, are synchronous to this fixed frequency clock and accept data streams whose sampling rate can be variable and modified in real time. The Architecture has been commissioned in a LLRF uTCA crate hosting the One Turn FeedBack algorithm to control a real SPS cavity. The algorithm compensates the Beam Loading. The Architecture has demonstrated its capability to track in real-time an energy ramp with an RF frequency following a linear sawtooth pattern ramped at 2.4 MHz per second. The complete uTCA implementation has successfully passed all the functional validation and qualitative tests. The Architecture suits seamless the two technological paradigm changes adopted for the new CERN SPS LLRF system; first, the instantaneous value of the RF frequency is transmitted as a numerical word (used to set the resampling ratio), via a deterministic network, the White Rabbit. And second, the reference signal is now the fixed frequency clock recovered from this network. Both paradigms benefit from the all-digital Resampler and the Beam Synchronous Architecture that fulfil the techniques and technological needs for its implementation enabling novel LLRF algorithms and solutions.
En un Acelerador de Partículas, el Low Level RF (LLRF) es el sistema de control de la RF, e implícitamente, de la transferencia de energía y aceleración de partículas, objetivo último de la máquina. El LLRF implementa algoritmos que sincronizan la transferencia de energía de RF hacia el haz, y controla sus parámetros longitudinales. Usa señales del haz, cuyo contenido espectral se modifica con la aceleración. El incremento en energía implica un incremento en velocidad del haz que, para aceleradores circulares (Sincrotrones), resulta en un decremento del periodo de revolución. Esto es relevante en aceleradores de Hadrones, en los cuales la baja energía de inyección favorece grandes incrementos de velocidad antes de alcanzar valores relativistas. El LLRF necesita por tanto sintonizar continuamente el procesado y el haz (Beam Synchronous Processing). Una misión del LLRF es la compensación de la tensión inducida por el haz en cavidades aceleradoras (Beam Loading). En el sincrotrón SPS del CERN, el ancho de banda de regulación cubre 5 MHz a cada lado de la RF (200 MHz). Con un periodo de revolución de aproximadamente 23 µs, más de cien harmónicos de la frecuencia de revolución, presentes en la señal del haz, aparecen en las bandas alrededor de la RF. La variación en velocidad del haz cambia la posición y espaciado de estos harmónicos en el espectro. Su número y posición cambiante hacen una opción poco deseable la reconfiguración en algoritmos de control. La solución histórica es un reloj de sistema derivado de la RF, por tanto variable, que liga por diseño el muestreo y procesado al haz. Aún en uso en varias máquinas, este reloj es ahora un factor limitante para el uso de nuevas tecnologías. Esta Tesis presenta una nueva Arquitectura para Tratamiento Síncrono de Señales derivadas del Haz, mediante un reloj de sistema con frecuencia fija, que posibilita el tratamiento de señales periódicas en las que el harmónico fundamental tiene una frecuencia variable y conocida. La Arquitectura es una alternativa válida al problema de reconfiguración de algoritmos de procesado; sintoniza el espectro al procesado mediante el re-muestreo de los datos. Dos Re-muestreadores (Resamplers) son combinados en el denominada sándwich de re-muestreo. El algoritmo requiriendo sincronismo con el haz, se sitúa en medio de este sándwich. El elemento clave es un novedoso Resampler digital que acepta relaciones de re-muestreo arbitrarias y modificables en tiempo real. El hardware usa un único reloj de sistema de frecuencia fija, facilitando la implementación en FPGAs, ASICs y sistemas de última generación, como los controladores uTCA en los sistemas LLRF del SPS en el CERN. Los puertos de entrada y salida del Resampler, y todo el procesado en la Arquitectura, son síncronos a este reloj, y aceptan señales con una frecuencia de muestreo variable en tiempo real.La Arquitectura ha sido implementada en un controlador uTCA de una cavidad del SPS albergando el algoritmo One Turn FeedBack. El algoritmo compensa el Beam Loading. La Arquitectura demuestra ser viable operando sintonizada a una rampa de aceleración del haz, con una RF cuya frecuencia varia linealmente a 2.4 MHz por segundo siguiendo un patrón en diente de sierra. La implementación de la Arquitectura ha pasado toda la validación funcional y test cualitativos. La Arquitectura se adapta de manera sin igual a dos cambios de paradigma tecnológico adoptados por el LLRF del SPS; primero, la distribución del valor instantáneo de la frecuencia de RF es ahora hecho mediante una palabra digital con una red determinista, White Rabbit. Y segundo, la señal de referencia es ahora un reloj con frecuencia fija extraído de esta red. La adopción de ambos paradigmas se ve beneficiada por el uso de la Arquitectura y Resampler, que satisfacen los requerimientos técnicos y tecnológicos para la implementación de nuevos algoritmos y soluciones LLRF.
Dans le monde des Accélérateurs de Particules, le Low-Level RF (LLRF) est le système de contrôle de la RF et, in-fine, du transfert d'énergie et de l'accélération des particules. Il met en oeuvre des algorithmes synchronisant la RF transférant l'énergie au faisceau et adaptant ses paramètres longitudinaux. Pour cela, le LLRF utilise des signaux liés au faisceau dont le contenu spectral est modifié par l'accélération. L'augmentation d'énergie se traduit par une augmentation de la vitesse du faisceau, et pour les accélérateurs circulaires (Synchrotrons), une diminution de la période de révolution. Cela est particulièrement pertinent pour les machines à Hadrons dont l’énergie d’injection est faible, avec la conséquence d’une augmentation significative de leur vitesse durant l’accélération. Le LLRF doit donc ajuster en permanence son traitement au faisceau ; nous appelons cette exigence Beam Synchronous Processing. Une tâche importante du LLRF est la compensation de la tension induite par le faisceau (Beam Loading). Dans le SPS au CERN, la régulation couvre 5 MHz de chaque côté de la RF (200 MHz). Avec une période de révolution autour de 23 μs, plus d'une centaine d’harmoniques de fréquence de révolution, présentes dans le spectre du faisceau, tombent dans la bande +- 5 MHz. La variation de vitesse du faisceau modifie la position et l'espacement des harmoniques dans le spectre. Le grand nombre de raies spectrales et leur position variable font de la reconfiguration de l'algorithme une option indésirable. Les solutions digitales existantes ont donc préféré changer l’horloge d’échantillonnage : Celle-ci est verrouillée sur la RF, ce qui synchronise par conception l'échantillonnage et le traitement du faisceau. Cette solution historique, toujours en usage dans plusieurs machines, est aujourd'hui un facteur limitant pour les technologies modernes. La Thèse présente une nouvelle Architecture de traitement synchrone de faisceau, utilisant une horloge fixe, et capable de traiter des signaux périodiques de fréquence fondamentale connue et possiblement variable. L'Architecture apporte une alternative au fardeau de la reconfiguration dans les algorithmes ; il ajuste le spectre au traitement en rééchantillonnant les données d'entrée. Deux Rééchantillonneurs ont été combinés dans le sandwich de rééchantillonnage. L'algorithme d'application nécessitant un synchronisme avec le signal d'entrée est placé au milieu. L'élément clé est un nouveau Ré-échantillonneur entièrement numérique basé sur une architecture Farrow, qui accepte des taux de rééchantillonnage arbitraires pouvant également être modifiés en temps réel. L’implémentation utilise une seule horloge système à fréquence fixe, ce qui rend sa mise en œuvre possible dans les FPGA, ASIC et systèmes de pointe comme la nouvelle plate-forme uTCA actuellement déployée dans le SPS du CERN. L’entrée et la sortie du Ré-échantillonneur, et tout le traitement dans l'Architecture, sont synchrones avec cette horloge et acceptent un taux d’échantillonnage variable que peut être modifiée en temps réel. L'Architecture a été déployée dans un châssis uTCA hébergeant l'algorithme One Turn FeedBack pour contrôler une véritable cavité SPS. L'algorithme compense le Beam Loading. L'Architecture a démontré sa capacité à suivre en temps réel une rampe d'énergie avec une fréquence RF suivant une modulation en dent de scie, à 2.4 MHz par seconde. L’implémentation complète sur uTCA a passé avec succès les tests de validation fonctionnelle et qualitative. L'Architecture convient parfaitement aux deux paradigmes technologiques adoptés pour le nouveau système LLRF du SPS ; premièrement, la valeur instantanée de la fréquence RF est transmise sous forme de mot numérique (qui donnera le taux de rééchantillonnage), via un réseau déterministe, le White Rabbit. Et deuxièmement, le signal de référence est maintenant l'horloge à fréquence fixe récupérée de ce réseau. La solution présentée respecte ces deux paradigmes grâce au Réchantillonneur entièrement numérique et à l'horloge fixe.
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Metabolic regulation of excitability is increasingly appreciated as a strategy to control seizures and reduce pathogenesis. Inhibiting or bypassing glycolysis may be one way in which the ketogenic diet suppresses seizures. 2-deoxy-D-glucose (2DG) is a glucose analog that partially inhibits glycolysis and has antiseizure effects in several acute and chronic seizure models. The mechanisms underlying the acute and chronic effects of 2DG are being investigated. Preliminary studies provide evidence that the acute anticonvulsant actions of 2DG involve activity-dependent presynaptic suppression of excitatory synaptic transmission during network synchronization. The chronic effects of 2DG entail reduction of the expression of brain-derived neurotrophic factor and its receptor, tyrosine kinase B. Preclinical toxicology studies demonstrate that 2DG has a favorable toxicity profile at doses effective for seizure protection. Currently available preclinical studies support 2DG as a novel first-in-class metabolic treatment for epilepsy with an antiglycolytic mechanism distinct from all other anticonvulsants.

In this paper, the synchronization dynamics of two gyroscope systems is discussed by the theory of discontinuous dynamical systems. The necessary and sufficient conditions of such synchronization are obtained. The non-synchronization, partial and full synchronizations of two gyroscope systems are illustrated for the analytical conditions of synchronization.

In this paper, chaotic synchronization of a controlled, noised gyroscope system with an expected gyroscope system is investigated. From the theory of discontinuous dynamical systems, the necessary and sufficient conditions of such synchronization are presented. Numerical simulations for non-synchronization, partial and full chaotic synchronizations of two gyroscope systems are carried out.

In this paper, the analytical conditions for the controlled pendulum synchronizing with periodic motions in Duffing oscillator is developed through the theory of discontinuous dynamical systems. The conditions for the synchronization invariant domain are obtained, and the partial and full synchronizations are illustrated for the analytical conditions.