Teses / dissertações sobre o tema "Gestion de fréquence"
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Lourdais, Olivier. "Coûts de la reproduction, gestion des ressources et fréquence des épisodes reproducteurs chez la vipère aspic (Vipera aspis)". Poitiers, 2002. http://www.theses.fr/2002POIT2303.
Texto completo da fonteThe number of reproductive episodes is a major life history trait. A classical distinction is made between semelparous (one reproductive event during the lifetime of the individual) and iteroparous organisms (repeated reproductive events). The aspic viper occupies an intermediate position while showing a low frequency of reproductions (one every 2-4 years) and a marked tendency toward semelparity. In this species the ecological and energetic constraints of reproduction are high and independent of reproductive effort and litter size. Our results indicate a close relationship between those reproductive constraints and reproductive frequency and thereby, support the Bull and Shine (1979) hypothesis. The original idea we developed relies on a connection between Bull and Shine's model and the strategy of energy acquisition and allocation. Our work points out a clear connection between fecundity-independent costs of reproduction, low frequency of reproduction and capital breeding systems. This study brings original informations about the condition favouring the emergence of "extreme" reproductive strategies and the evolutionary transition toward semelparity
Leterme, Anne-Claire. "Apport des nouvelles technologies à la gestion du stress : e-TCC et biofeedback de variabilité de fréquence cardiaque". Thesis, Lille 2, 2020. http://www.theses.fr/2020LIL2S008.
Texto completo da fonteStress is a major public health issue, responsible for the development and aggravation ofa large number of somatic (cardiovascular diseases, cancers, infectious diseases, etc.) andpsychiatric (anxiety, depression, etc.) disorders. Stress management through cognitive,behavioral and emotional therapies (CBT) is effective to reduce the negative consequencesof stress and prevent disorders in people at risk, but its access remains limited. Internetand new digital technologies, in particular self-help, e-CBT and heart rate variabilitybiofeedback (HRV biofeedback) have the potential to enrich CBT-based stressmanagement programs and make their access easier. In this context, the objective of thisthesis was to develop and evaluate innovative treatment formats using CBT and newtechnologies.Initially, the Seren@ctif program, the first French e-CBT program dedicated to stressmanagement, was evaluated in a randomized controlled trial on 120 patients respondingto the diagnosis of adjustment disorder with anxiety (ADA) according to the DSM-5criteria and consulting in the outpatient psychiatry service of the Lille University Hospital.The results showed that internet-based CBT guided by a human face-to-face contact timewith a supervised health professional (blended CBT) is as effective as the same face-tofaceCBT program for the treatment of ADA, compared to a control group of patientsbenefiting from usual care by their general practitioner.Secondly, a new HRV biofeedback, directly based on vagal activation, was designed froma new measure of parasympathetic activation developed by the team of ClinicalInvestigation Center of Innovative Technology at Lille. The different stages of elaborationof this new biofeedback are presented, followed by a proof of concept carried out onseveral patients with various anxiety and depressive disorders. This new HRV biofeedbackis a promising approach to non-invasively stimulate the vagus nerve. It could alsosustainably improve vagal activation and physiologically objectify the beneficial effect ofMindful Breathing. It could be complementary to the traditional respiratory sinusarrhythmia biofeedback and would allow to diversify the behavioral techniques associatedwith biofeedback.Researches presented in this thesis contribute to advancing research in the field ofinformation technologies applied to mental and behavioral health. They open upinnovative perspectives on a new way to deliver an internet-based CBT, on the potentialeffectiveness of a new HRV biofeedback or on the interest of a new marker of flexibilityof the autonomic nervous system in the objective evaluation of the effectiveness of thethird wave of CBT, especially Mindfulness
BOUDET, GIL. "Limites de l'utilisation de la fréquence cardiaque dans la gestion d'efforts exhaustifs au laboratoire, sur le terrain et en compétition". Clermont-Ferrand 1, 2001. http://www.theses.fr/2001CLF1MM25.
Texto completo da fonteSissokho, Bamba. "Gestion des interférences dans les systèmes MIMO massifs". Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0008/document.
Texto completo da fonteThis thesis made it possible to work on the efficiency of a channel of massive MIMO systems for which it is necessary to determine the throughput at the Uplink of the terminals present in their respective cells. As an assumption, the frequency band in TDD mode is reused in each cell. All symbols are propagated asynchronously by the terminals present in the cells, not effectively preventing intra- and inter-symbol interactions at the base stations. These signals encounter many obstacles on their path that lead to delays, signal losses (destructive), signal regenerations (constructive) with various types of modulation (amplitude, frequency, phase), etc. The path loss in the channel is highlighted with the different values taken by the attenuation coefficient chosen during the simulations. Faced with this situation, it was necessary to look for the best and most robust channel estimator at a given consistency time. The MMSE (Minimum Mean Square Error) method is used, compared to others. For the performance of massive MIMO systems, we have focused on antenna diversity methods (N-order diversity), coding methods, OFDMA access methods and equalization methods to show that effectively using multiple antennas at base stations improves and contributes to the desired rate gains. With massive MIMO systems, we have shown that antennar contribution is well recognized in interference management. An algorithm for calculating the flow rate at the Uplink was developed using three conventional receivers: the MRC (Maximum Ratio Combiner), the ZF (Zero-Forcing) and the MMSE (Minimum Mean Square Error). The simulations made it possible to compare the different approaches. By varying the contamination power of the pilot symbols, we observe the convergence of the ZF and MMSE curves. If the number of L cells increases, we find that the higher the contamination power of the pilot symbols (pp), the lower the capacity in the channel. After several iterations, our algorithm converges to an asymptote (stationary and linear regime) where the samples at the detector output approach the transmitted data sequence. The SINR obtained with conventional detectors allows the calculation of the respective flows in the channel with the SHANNON theorem
Ben, Amor Inès. "Gestion dynamique de la consommation de récepteurs RF : intégration de fronts-end RF ultra faible consommation". Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4323.
Texto completo da fonteThe emergence of the Internet of Things (IoT), sensors networks and new networks to objects requires the development of a new ecosystem. Nowadays, it upsets many sectors of our society. It solicits design of low power radio transceivers as reducing energy consumption presents a major constraint in the case of these applications in order to obtain greater autonomy. In this context, the purpose of the thesis is to provide techniques allowing reducing the power consumption of radio frequency receivers while seeking to minimize the impact of these technologies on the performance of the achieved receiver. In order to realize a demonstrator consists of a transmitter and receiver for video transmission, two UWB receivers with dynamic power management have been made in 0.13µm HCMOS9 technology from STMicroelectronics. First, a study of dynamic power management techniques on analog radio frequency circuits was proposed. This study was conducted on different circuits that seem to be the most used in design of analog circuits at high frequencies. The proposed technique allows to turn on and off the circuit between two pulses received to reduce their consumption. The application of this technique also requires a reduction of the latency caused by the ignition and the extinction radio frequency functions. In this case, a model to minimize the impact of the encapsulating effect has been proposed. Secondly, the first receiver was performed for 6-10GHz frequency band and implements dynamic power management using the technique of "Power Gating"
Akgul, Yeter. "Gestion de la consommation basée sur l’adaptation dynamique de la tension, fréquence et body bias sur les systèmes sur puce en technologie FD-SOI". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20132/document.
Texto completo da fonteBeyond 28nm CMOS BULK technology node, some limits have been reached in terms of performance improvements. This is mainly due to the increasing power consumption. This is one of the reasons why new technologies have been developed, including those based on Silicon-On-Insulator (SOI). Moreover, the standardization of complex architectures such as multi-core architectures emphasizes the problem of power management at fine-grain. FD-SOI technologies offer new power management opportunities by adjusting, in addition to the usual parameters such as supply voltage and clock frequency, the body bias voltage. In this context, this work explores new opportunities and searches novel solutions for dynamically manage supply voltage, clock frequency and body bias voltage in order to optimize the power consumption of System on Chip.Adjusting supply voltage, frequency and body bias parameters allows multiple operating points, which must satisfy the constraints of functionality and performance. This work focuses initially at design time, proposing a method to optimize the placement of these operating points. An analytical solution to maximize power savings achieved through the use of several operating points is provided. The second important contribution of this work is a method based on convexity concept to dynamically manage the supply voltage, the frequency and the body bias voltage so as to optimize the energy efficiency. The experimental results based on real circuits show average power savings reaching 35%
Dahmane, Yassir. "Gestion d'énergie optimisée étendue véhicules infrastructures". Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0047.
Texto completo da fonteThis PhD thesis is part of the Renault/Centrale Nantes chair on improving the performance of electric vehicles (EV/PHEV). It is dedicated to the problem of the charging management of electric vehicles, using optimization algorithms and smart charging strategies. In this framework, several contributions have been proposed on the topics of smart charging of an EV and the smart energy management of an EV fleet, considering the mobility constraints (desired SOC at the end of the charging and departure time), the temperature of the Li-ion bat teries, the charging infrastructures, and the power grid. On the subject of smart charging of an EV, the contributions focused on the development of embedded algorithms allowing the scheduling of the charging power profile in order to reduce the charging cost. The proposed algorithms take into account the mobility needs of electric vehicle users, and the effect of temperature on the charging power of Li-ion batteries. On the subject of fleet energy management, the contributions focus on centralized algorithms in electric vehicle charging stations. An unidirectional recharging algorithm has been proposed in or der to evaluate the optimal number of electric vehicles to be recharged with a good level of satisfaction of mobility constraints and without any infrastructure reinforcement. The switch to the bidirectional algorithm is due to the exploitation of the V2G functionality, which will allow the participation of electric vehicles in frequency regulation. The proposed contributions on the first topic have the advantage of increasing the estimation accuracy of final SOC in very low temperature, and to be embedded on the EV due to the low computational capacity of the algorithms and the speed of execution. On the other hand, the EV fleet charging manage ment algorithms allow the possibility of large-scale integration of electric vehicles on the grid and show the potential of EVs in contributing to the stability of the power grid by offering ancillary services such as frequency regulation. The algorithms and strategies developed have been tested in simulation and will be tested on an EV charging system. The results obtained have highlighted the benefits of smart charg ing on cost reduction and grid benefits and the importance of electric vehicle fleet charging management in the development of grid services
Couble, Yoann pierre. "Optimisation de la gestion des ressources voie retour". Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0058.
Texto completo da fonteOptimizing satellite links is a major challenge to increase satellite systems profitability. Increasing the frequency reuse is one of the most promising approaches. Reusing multiple times the same frequency enables to transmit more information on the same frequency, as long as the two or more signals do not generate too high mutual interferences. It is therefore of capital importance to control these interference impacts, be it through the use of frequency reuse scheme or through the use of advanced dynamic interference coordination techniques, where the user selection is done with the knowledge of interference levels
Giret, Rébecca. "Imagerie radar par synthèse d'ouverture pour la gestion du trafic autoroutier". Phd thesis, INSA de Rennes, 2003. http://tel.archives-ouvertes.fr/tel-00922039.
Texto completo da fonteBen, Amor Inès. "Gestion dynamique de la consommation de récepteurs RF : intégration de fronts-end RF ultra faible consommation". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4323.
Texto completo da fonteThe emergence of the Internet of Things (IoT), sensors networks and new networks to objects requires the development of a new ecosystem. Nowadays, it upsets many sectors of our society. It solicits design of low power radio transceivers as reducing energy consumption presents a major constraint in the case of these applications in order to obtain greater autonomy. In this context, the purpose of the thesis is to provide techniques allowing reducing the power consumption of radio frequency receivers while seeking to minimize the impact of these technologies on the performance of the achieved receiver. In order to realize a demonstrator consists of a transmitter and receiver for video transmission, two UWB receivers with dynamic power management have been made in 0.13µm HCMOS9 technology from STMicroelectronics. First, a study of dynamic power management techniques on analog radio frequency circuits was proposed. This study was conducted on different circuits that seem to be the most used in design of analog circuits at high frequencies. The proposed technique allows to turn on and off the circuit between two pulses received to reduce their consumption. The application of this technique also requires a reduction of the latency caused by the ignition and the extinction radio frequency functions. In this case, a model to minimize the impact of the encapsulating effect has been proposed. Secondly, the first receiver was performed for 6-10GHz frequency band and implements dynamic power management using the technique of "Power Gating"
Aimene, Merzak. "Services au système et gestion d'interactions énergétiques transitoires dans un parc éolien offshore". Thesis, Le Havre, 2016. http://www.theses.fr/2016LEHA0020/document.
Texto completo da fonteThe massive integration of intermittent production of wind energy in electrical networks creates an electrical system stability problem. Indeed, its characteristics are very different from those of conventional sources controlled by Grid managers. Therefore, the injection of this energy makes new challenges for power Grid operators. Moreover, the connection conditions are evolving and go towards the situations that all different sources participate into services of electrical systems. This thesis proposes a new nonlinear control strategy based on a « one loop flatness control » of a wind energy conversion system. This control strategy has aim of energy interactions management at the connection point through generation and tracking of reference trajectories. As all system variables are functions of the « flat output » of the system, this control provides fast response and good control in transient state. The application of this new control strategy into an offshore wind farm which is able to satisfy different connection conditions was simulated successfully. Specifically, effects of various grid faults on the proposed ancillary services (frequency and voltage regulation, and low-voltage ride through capabilities) were performed
Delille, Gauthier Marc Aimé. "Contribution du Stockage à la Gestion Avancée des Systèmes Électriques : approches Organisationnelles et Technico-économiques dans les Réseaux de Distribution". Phd thesis, Ecole Centrale de Lille, 2010. http://tel.archives-ouvertes.fr/tel-00586088.
Texto completo da fonteLaurent, Fabrice. "Contribution au dimensionnement d'une série de machines électriques à axe vertical et au développement d'un système passif de filtrage de vibrations d'origine magnétique pour moteurs électriques". Nancy 1, 2001. http://www.theses.fr/2001NAN10024.
Texto completo da fonteThe aim of this research concerns two different contributions relative to vibrations in induction machines. The first part presents the design of a new vertical electrical machine range. The position of the first natural frequency of the machine is a major constraint for the design. The electrical machine range is modeled and natural frequencies of each motor are calculated. Associated meshing and a shell finite element code are dedicated to this application. The model has been validated by experimental results. The second part of thesis presents the simulation of a passive system for magnetic vibrations reduction in induction machines. The role of the stator in vibrations transmission is demonstrated. A precise determination of natural frequencies and modes shapes of stator is funldamental in order to avoid coincidence with excitation frequencies excitation. Dedicated meshing of the stator and three dimensional volumic finite element code are developed. An experimental modal analysis method of the stator is presented. We emphasized the complexity of stator material rheology. Numerical and experimental results are adjusted with an optimization method
Cochet, Martin. "Energy efficiency optimization in 28 nm FD-SOI : circuit design for adaptive clocking and power-temperature aware digital SoCs". Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4370.
Texto completo da fonteEnergy efficiency has become a key metric for digital SoC, especially for applications relying on batteries or energy harvesting. Hence, this work proposes new designs for on-chip flexible clock generator, power monitor and temperature sensor as well as the integration of those blocks within complete SoC.The novel open-loop clock multiplier architecture enables fast frequency scaling and is implemented to operate on the same voltage-frequency range as a digital core ((53MHz 0.5V - 889MHz 0.9 V). The achieved extremely low area (981µm2) and power consumption 0.45pJ/cycle 0.5 V) also ease its integration within low power SoC. The proposed power monitor instruments switched capacitor DC-DC converters, which are standard components of low voltage SoCs. The monitor has been demonstrated over two different converters topologies and provides a measurement of both the converter input and output power within 2.5% to 6% accuracy. Last, a new principle of temperature sensor is proposed. It leverages single n well body-biasing for calibration and integrated digital logic for large non-linearity correction. It is expected to achieve within 1C accuracy 0.1nJ / sample and 225 µm2 probe area. Then, this work illustrates how those circuits can be integrated within complex SoCs power management strategies. First, a modeling study of body biasing highlights the benefits it can provide in complement to voltage scaling, accounting for a wide temperature range. Last, three example of power management are proposed at SoC level
Gouicem, Redha. "Thread scheduling in multi-core operating systems : how to understand, improve and fix your scheduler". Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS052.
Texto completo da fonteIn this thesis, we address the problem of schedulers for multi-core architectures from several perspectives: design (simplicity and correctness), performance improvement and the development of application-specific schedulers. The contributions presented are summarized as follows : - Ipanema, a domain-specific language dedicated to thread schedulers for multi-core architectures. We also implement a new abstraction in the Linux kernel that enables the dynamic addition of schedulers written in Ipanema. - a series of performance and bug tracking tools. Thanks to these tools, we show that the Linux scheduler, CFS, suffers from a problem related to frequency management on modern processors. We propose a solution to this problem in the form of a patch submitted to the community. This patch allows to significantly improve the performance of numerous applications. - a scheduler model in the form of a “feature tree”. We implement these features independently in order to offer a new fully modular scheduler. This modular scheduler allows us to study exhaustively the different combinations of features, thus paving the way for the development of application-specific schedulers
Cochet, Martin. "Energy efficiency optimization in 28 nm FD-SOI : circuit design for adaptive clocking and power-temperature aware digital SoCs". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4370.
Texto completo da fonteEnergy efficiency has become a key metric for digital SoC, especially for applications relying on batteries or energy harvesting. Hence, this work proposes new designs for on-chip flexible clock generator, power monitor and temperature sensor as well as the integration of those blocks within complete SoC.The novel open-loop clock multiplier architecture enables fast frequency scaling and is implemented to operate on the same voltage-frequency range as a digital core ((53MHz 0.5V - 889MHz 0.9 V). The achieved extremely low area (981µm2) and power consumption 0.45pJ/cycle 0.5 V) also ease its integration within low power SoC. The proposed power monitor instruments switched capacitor DC-DC converters, which are standard components of low voltage SoCs. The monitor has been demonstrated over two different converters topologies and provides a measurement of both the converter input and output power within 2.5% to 6% accuracy. Last, a new principle of temperature sensor is proposed. It leverages single n well body-biasing for calibration and integrated digital logic for large non-linearity correction. It is expected to achieve within 1C accuracy 0.1nJ / sample and 225 µm2 probe area. Then, this work illustrates how those circuits can be integrated within complex SoCs power management strategies. First, a modeling study of body biasing highlights the benefits it can provide in complement to voltage scaling, accounting for a wide temperature range. Last, three example of power management are proposed at SoC level
Fournié, Claire. "Activité physique adaptée et cohérence cardiaque en soins de support : leurs effets sur la variabilité de la fréquence cardiaque et la qualité de vie en post-traitement d’une hémopathie maligne". Thesis, La Réunion, 2020. http://www.theses.fr/2020LARE0009.
Texto completo da fonteIntroduction: Hematologic malignancies require aggressive treatment, including intensivechemotherapy and sometimes hematopoietic stem cell transplantation. The repercussions of cancer and its treatment is recognized for their significant long-term adverse effects on health-related quality of life. As a part of cancer treatment, physical exercise is known to improve mainly physical functioning and fatigue, but there are still questions regarding its impact on psychological and emotional functioning. Nonetheless, heart rate variability biofeedback (HRVB) is recognized for its positive effects on autonomic nervous system balance and emotional self-regulation. Recent research in neurocardiology has shown the benefits of Cardiac Coherence (CC) training on the autonomic balance and the psycho-emotional state. Method: The objectives of the research undertaken in this thesis are to evaluate the effects of a nonpharmacological intervention on quality of life in adult hematologic patients in post-treatment time. The recovery of physiological balance is indexed by the Heart Rate Variability (HRV), which is recognized as a window of the Autonomic Nervous System (ANS). We present four studies: an experimental study in healthy subjects to better understand the mechanisms of HRV during slow and deep breathing; a feasibility study on the implementation of an APA program in hematology; preliminary results of a randomized controlled trial evaluating the effects of a program associating APA and CC on HRV, quality of life, fatigue and anxiety-depression; and a qualitative study evaluating the program’s implementation and the effects of the both interventions. Results: Our results first show the feasibility of APA and CC in these patients. Although the results of the HRV analysis are inconclusive, they tend to confirm that CC intervention results in stimulation of vagal tone. Qualitative evaluation provides us with many important insights into the appropriateness of the interventions to the specific needs of the patients and their effectiveness in optimizing a return to the active daily life. Discussion: This research provides new experimental evidence in understanding the mechanisms of cardiac coherence and its applications in the clinical setting. Further experimentation is still needed to deepen our knowledge in the context of a psychophysiological approach in APA on cancer
Pomportes, Stéphane. "Mobilité et gestion efficace des fréquences dans un réseau ad hoc à forte efficacité". Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00662530.
Texto completo da fontePomportes, Stephane. "Mobilité et gestion efficace des fréquences dans un réseau ad hoc à forte efficacité". Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112318/document.
Texto completo da fonteWhen a major disaster occurs, such as an earthquake or fire, the efficiency of the rescue workers depends of the coordination between the different emergency teams. This coordination needs reliable communication equipments. In such a situation, however, the infrastructure for wireless communication is generally destroyed or unusable. It is therefore necessary to find adapted communication tools for the rescue workers known as opportunistic networks. These networks pose new challenging problems such as, for instance, resource allocation which is particularly important for the QoS satisfaction. In the first part of our thesis, we addressed the problem of resource allocation in ad hoc networks using the TDMA access mechanism. Our solutions aim to perform a fair distribution of channels and take into account an interference area twice as large as the transmission range. Evaluation of new policies for opportunistic networks deployed in disaster areas requires new mobility models. We developed a novel mobility model dedicated to the movement of rescue workers. Our model includes the group mobility and some characteristics of human mobility. It also incorporates a mechanism to circumvent obstacles presents in the simulation area
GUITTON, Patricia. "Estimation et Optimisation de la Consommation lors de la conception globale des systèmes autonomes". Phd thesis, Université de Nice Sophia-Antipolis, 2004. http://tel.archives-ouvertes.fr/tel-00007496.
Texto completo da fonteUne première étude consiste à estimer la consommation des divers composants d'une architecture SoC. Puis, nous nous sommes intéressés aux deux étapes principales des méthodes de partitionnement : l'allocation et l'ordonnancement. En particulier,
la technique d'ajustement conjoint de la tension et de la fréquence est considérée dans l'ordonnancement pour minimiser l'énergie. A la suite de ces optimisations, une gestion des modes basse consommation est réalisée, ayant pour objectif de mettre les processeurs en état de repos ou repos profond dès que la possibilité se présente, ce changement de mode permettant de gagner en consommation. Ce travail a été testé sur divers exemples, comme une application de détection de mouvement sur fond d'images
fixes pour caméra embarquée.
M'saddek, Oussama. "Essays in international finance : risk, jumps and diversification". Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAD009.
Texto completo da fonteThis thesis consists of an introductory chapter and three empirical studies that contribute to the international finance literature by investigating the dynamics of cojumps between major equity markets and assessing their impact on international portfolio allocation and asset pricing. The first study aims to examine the impact of cojumps between international stock markets on asset holdings and portfolio diversification benefits. Using intraday index-based data for exchange-traded funds (SPY, EFA and EEM) as proxies for international equity markets, we document evidence of significant intraday cojumps, with the intensity increasing during the global financial crisis of 2008-2009. The application of the Hawkes process also shows that jumps propagate from the US and other developed markets to emerging markets. However, the evidence of jump spillover from emerging markets to developed markets is weak. To assess the impact of cojumps on international asset holdings, we consider a representative American investor who allocates his wealth among one domestic risky asset, the SPY fund, and two foreign risky assets, the EFA and EEM funds and compute the optimal portfolio composition from the US investor perspective by minimizing the portfolio's risk. We find that the demand of foreign assets is negatively correlated to jump correlation, implying that a domestic investor will invest less in foreign markets when the frequency of cojumps between domestic and foreign assets increases. In contrast, idiosyncratic jumps are found to increase the diversification benefits and foreign asset holdings in international equity portfolios.The second study tackles the issue of pricing of both continuous and jump risks in the cross-section of international stock returns. We contribute to the literature on international asset pricing by considering a general pricing framework involving six separate market risk factors. We first decompose the systematic market risk into intraday and overnight components. The intraday market risk includes both continuous and jump parts. We then consider the asymmetry and size effects of market jumps by separating the systematic jump risk into positive vs. negative and small vs. large components. Using the intraday data of a set of country exchange traded funds covering developed, emerging and frontier markets, we show that continuous and downside discontinuous risks are positively rewarded in the cross-section of expected stock returns during the pre-financial crisis period whereas the upside and large jump risks are negatively priced during the crisis and post-crisis periods.The third study examines how international equity markets respond to aggregate market jumps at price and volatility levels. Using intraday data of ten exchange-traded funds covering major developed and emerging markets and two international market volatility indices (VIX and VXEEM), we show that both price and volatility jump betas are time-varying and exhibit asymmetric effects across upside and downside market movements. Looking at the relation between future stock market returns and aggregate market price and volatility jumps, we measure the proportion of future excess returns explained by market price and volatility jumps and provide evidence of a significant predictive power that market price and volatility jumps have on future stock returns
Fares, Adnan. "Development of advanced architectures of power controllers dedicated to Ultra High Switching Frequency DC to DC converters". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS195.
Texto completo da fonteThe continuous sophistication of smart handheld devices such as smartphones and tablets creates an incremental need for improving the performances of the power conversion devices. The trend in power delivery migrates progressively to higher frequency, higher density of integration and flexibility of the control scheme. Dynamic Voltage Scaling Power Management ICs (DVS PMIC) are now systematically used for powering RF Transmitters and DVFS PMICS using Voltage and Frequency scaling are used for CPUs and GPUs. Flexible High frequency (HF) DC/DC converters in conjunction with low dropout LDOs constitute the main solution largely employed for such purposes. The migration toward high frequency/small size DCDC solutions creates serious challenges which are: 1) the stability of the feedback loop across a wide range of loading voltage and current conditions 2) The complexity of the control and often-non-synchronous state machine managing ultra large dynamics and bridging low power and high power operating modes, 3) The portability of the proposed solution across technology processes.The main stream solutions have so far reached the range of 2 to 6 MHz operation by employing systematically sliding mode or hysteretic converters that suffer from their variable operating frequency which creates EMI interferences and lead to integration problems relative to on-chip cross-talk between converters.In this work we aim at extend the use of traditional design and modeling techniques of power converters especially the average modeling technique by putting a particular care on the simplification of the theory and adjunction of flexible compensation techniques that don't require external components and that are less sensitive to process spread, or to high frequency substrate and supply noise conditions.The Small Signal Average Models, widely treated in the existing literature, might address most needs for system modeling and external compensation snubber design, especially when aiming on the high frequency natural zero of the output capacitor. However, HFDCDC converters today use small size MLCC capacitors with a very low ESR which require using alternative techniques mixing the compensation scheme with the duty cycle generation itself. The literature often provides a simplistic state machine description such as PWM/PFM operations but doesn't cover combined architectures of synchronous / non synchronous mode operations such as PWM, PFM, Current Limit, Boundary Clamp, Start, Transitional and finally Fault or Protection modes.In our work, we have focused our study on two main axes: 1) The parametric modeling and the loop compensation of HFDCDC and 2) the scalability of the control state machine and mode inter-operation. In the first part, we provided a detailed small signal averaged model of the “voltage and current mode buck converter” and we depicted it to emphasize and optimize the contributions of the Proportional, Integral and Derivative feedback loops. We demonstrated the ability to use the current feedback to damp and stabilize the converter with a wide variety of loading conditions (resistive or capacitive). In the second part, we provided architecture of the mode control state machine with different modes like the PWM, PFM, soft-start, current limit,… .The technique we have used is inspired by Huffman machine with a significant effort to make it abstract and scalable. The state machine is implemented using RTL coding based on a generic and scalable approach.The theoretical effort has been implemented inside a real PMIC test-chip carrying two 12MHz buck converters, each employing a voltage and current mode feedback loop. The chip has been realized in a 0.5um / 0.18um BiCMOS technology and tested through a dedicate Silicon validation platform able to test the analog, digital and power sections. The key performance obtained is a 50mV load transient undershoot / overshoot during 2us following a load step of 300mA (slope 0.3A/ns)
Chouayakh, Ayman. "Jeux d'acteurs et mécanismes d'enchères dynamiques pour la gestion de spectre dans les réseaux 5G". Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2020. http://www.theses.fr/2020IMTA0177.
Texto completo da fonteIn 5G networks, new spectrum sharing concepts such as Licensed Shared Access (LSA) will be implemented in order to optimize spectrum usage: a Mobile Network Operator can access temporarily to other incumbent's spectrum after obtaining a license. The LSA concept guarantees to the incumbent and the LSA licensee a certain level of QoS according to the LSA license. The licensing process is made via an auction mechanism. The mechanisms proposed in the literature for the LSA context are one-shot auction mechanisms which allocate all the available spectrum as a one block. In this thesis, first we show how to increase the performances of those auctions(in terms of revenue, efficiency and fairness of the allocation)-while preserving truthful bidding-by splitting spectrum and converting single block auctions to multi-blockauctions. Then, we show how to convert one-shot mechanisms to equivalent ascending mechanisms (in terms of allocations and payments) so that we add transparency andprivacy to the auction
Laborde, Sylvain. "Slow-paced breathing and cardiac vagal activity : influence on stress regulation, sleep, and cognitive executive performance The effect of slow-paced breathing on stress management in adolescents with intellectual disability Influence of a 30-day slow paced breathing intervention compared to social media use on subjective sleep quality and cardiac vagal activity The influence of slow-paced breathing on executive function Influence of slow-paced breathing on inhibition after physical exertion". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC044.
Texto completo da fonteThis PhD thesis was aimed to investigate the influence of slow-paced breathing (SPB) without biofeedback on CVA, as well as its action on several self-regulation processes, based on the neurovisceral integration model (Smith et al., 2017; Thayer et al., 2009) and on the resonance model (Lehrer & Gevirtz, 2014). Four studies were conducted, adolescents with individual disabilities (Study 1) and healthy young adults (Study 2, 3, & 4). Both short-term and long-term SPB interventions have been investigated, and positive effects have been found on stress management (short-term, Study 1), sleep (long-term, Study 2), and executive functions (short-term, Studies 3 and 4), however results related to executive functions were not mediated by CVA. These results are encouraging regarding the use of SPB in acute and chronic interventions, as a “quick-fix” or daily routine, however future research has to clarify the underlying mechanisms, in particular with brain imaging methods. To conclude, SPB is a technique that is free, non-invasive, easy to implement, and with little side effects, which makes it an appropriate intervention to recommend to address a large range of self-regulation phenomena
Reguillet, Vincent. "Caractérisation d’un système pile à combustible en vue de garantir son démarrage et fonctionnement à température ambiante négative". Thesis, Besançon, 2013. http://www.theses.fr/2013BESA2035/document.
Texto completo da fonteFuel cells are electric generators on the way to achieve technological and commercial maturity. Nevertheless, to compete with similar energy generating systems such as batteries and engines generators, fuel cells must overcome several obstacles. Among them, the ability to start at negative ambient temperatures is decisive. In order to study the behaviour of a PEMFC system in cold weather, we propose different exergetic criteria adapted to the working conditions of each module. Thanks to dedicated test benches, the modules are then characterized at negative ambient temperature. From experimental results, empirical or semi-analytical models are introduced for the battery, the compressor and the humidifier. On the other hand, a thermal analytical model at the stacks scale is developed. It enables to reproduce the fuel cell temperature rise during a cold start up. Eventually, at the end of the analysis of experimental results and models, recommendations are given to favour the cold start of the system. By following these recommendations, the fuel cell cold start at -10 °C is ensured
Dugast, Jérôme. "Essais en Microstructure des Marchés Financiers". Phd thesis, Jouy-en Josas, HEC, 2013. http://pastel.archives-ouvertes.fr/pastel-00940976.
Texto completo da fonteDeschatre, Thomas. "Dependence modeling between continuous time stochastic processes : an application to electricity markets modeling and risk management". Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLED034/document.
Texto completo da fonteIn this thesis, we study some dependence modeling problems between continuous time stochastic processes. These results are applied to the modeling and risk management of electricity markets. In a first part, we propose new copulae to model the dependence between two Brownian motions and to control the distribution of their difference. We show that the class of admissible copulae for the Brownian motions contains asymmetric copulae. These copulae allow for the survival function of the difference between two Brownian motions to have higher value in the right tail than in the Gaussian copula case. Results are applied to the joint modeling of electricity and other energy commodity prices. In a second part, we consider a stochastic process which is a sum of a continuous semimartingale and a mean reverting compound Poisson process and which is discretely observed. An estimation procedure is proposed for the mean reversion parameter of the Poisson process in a high frequency framework with finite time horizon, assuming this parameter is large. Results are applied to the modeling of the spikes in electricity prices time series. In a third part, we consider a doubly stochastic Poisson process with stochastic intensity function of a continuous semimartingale. A local polynomial estimator is considered in order to infer the intensity function and a method is given to select the optimal bandwidth. An oracle inequality is derived. Furthermore, a test is proposed in order to determine if the intensity function belongs to some parametrical family. Using these results, we model the dependence between the intensity of electricity spikes and exogenous factors such as the wind production
Gaveau, Jérôme. "Allocation des Ressources pour la Gestion Dynamique du Spectre dans les Réseaux Ad hoc Clustérisés". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC060/document.
Texto completo da fonteThis thesis deals with the fully distributed allocation of channels in clustered ad hoc networks. Nodes are gathered locally into clusters in order to keep the advantage of the no infrastructure of ad hoc networks, and to reduce the amount of signalling. In each cluster a node is elected as the Clustered Head (CH) whose role is to manage the resources and the transmissions locally. One of the major problem is to allocate in a distributed way spectrum bands to the clusters in order to make them able to operate. Bandwidth is a scarce resource which implies that several clusters may use the same frequency and hence interfere among each other. The CH realizes the frequency allocation based on a utility function that uses measurements as inputs. These measurements are possibly disturbed due to the wide variety of dynamic changes that face ad hoc networks. Among the distributed learning algorithms, we have identified approaches based on "trial and error'' (TE) paradigm that could solve the channel allocation problem. These approaches possess very attractive global convergence behavior despite the non-cooperativeness of the problem and thus in a broad class of games.First, based on a specific utility model, we analyse the performance of these algorithms using Markov chains approximations in order to reduce numerical computations complexity. Then, we assess theoretically and numerically that a drawback of TE algorithms is their sensitivity to disturbances. We propose modifications with supporting theoretical proofs in order to adapt the TE algorithms to disturbances of the utility. Furthermore, we study the impact of Rayleigh fading on the utility by deriving its probability density function (pdf) in various contexts
Ghazali, Daniel Aiham. "Relation stress - performance et effet de la répétition de séances de simulation sur le stress et la performance d'une équipe pluri-professionnelle lors de la prise en charge médicale d'une urgence vitale". Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT1404/document.
Texto completo da fonteIntroduction: The management of a life-threatening event by caregivers requires technical and non-technical skills under stress conditions. Simulation-based education allows this training in a safe environment. Objective: To analyze the association between stress and performance and the effect of repeated simulation.Methods: Two experimental and control groups of 6 MDTs of EMS (n=48) had respectively 9 (1session/6 weeks) and 3 (1session/6 months) simulations with 3 common sessions: initial, intermediate after 6 months, and final session after 1 year. Stress was assessed by heart rate and variability, salivary cortisol and psychological parameters (acute stress: STAI and SOM, and PTSD: IES-R and PCLS). The technical performance was evaluated by Intra-Osseous Access Performance Assessment Scale (IO), overall performance (TAPAS); non-technical performance by BAT score for leader and CTS score for teamwork.Results: Stress increased during simulation (p<0.02) and decreased during debriefing (p<0.01) regardless of the frequency of repetition. There was no PTSD. The performances were correlated between each other (p<0.001) with a strong link between the non-technical performance of leader and team (R²=0.93). Stress and performance were not correlated. The performance was higher in the experimental group during the intermediate scenario for technical scores (TAPAS: p=0.02, IO: p=0.03) and for all scores during the final scenario (TAPAS and IO: p=0.01 CTS: p=0.03, BAT : p=0.02).Conclusion: The benefit was greater when performing simulations every six weeks in terms of technical and non-technical performance. The team performance was linked to the leader performance
Trabelsi, Nessrine. "A Game Theoretic Framework for User Association & Inter-cell Interference Management in LTE Cellular Networks". Thesis, Avignon, 2016. http://www.theses.fr/2016AVIG0215/document.
Texto completo da fonteDriven by an exponential growth in mobile broadband-enabled devices and a continue dincrease in individual data consumption, mobile data traffic has grown 4000-fold over the past 10 years and almost 400-million-fold over the past 15 years. Homogeneouscellular networks have been facing limitations to handle soaring mobile data traffic and to meet the growing end-user demand for more bandwidth and betterquality of experience. These limitations are mainly related to the available spectrumand the capacity of the network. Telecommunication industry has to address these challenges and meet exploding demand. At the same time, it has to guarantee a healthy economic model to reduce the carbon footprint which is caused by mobile communications.Heterogeneous Networks (HetNets), composed of macro base stations and low powerbase stations of different types, are seen as the key solution to improve spectral efficiency per unit area and to eliminate coverage holes. In such networks, intelligent user association and interference management schemes are needed to achieve gains in performance. Due to the large imbalance in transmission power between macroand small cells, user association based on strongest signal received is not adapted inHetNets as only few users would attach to low power nodes. A technique based onCell Individual Offset (CIO) is therefore required to perform load balancing and to favor some Small Cell (SC) attraction against Macro Cell (MC). This offset is addedto users’ Reference Signal Received Power (RSRP) measurements and hence inducing handover towards different eNodeBs. As Long Term Evolution (LTE) cellular networks use the same frequency sub-bands, mobile users may experience strong inter-cellxv interference, especially at cell edge. Therefore, there is a need to coordinate resource allocation among the cells and minimize inter-cell interference. To mitigate stronginter-cell interference, the resource, in time, frequency and power domain, should be allocated efficiently. A pattern for each dimension is computed to permit especially for cell edge users to benefit of higher throughput and quality of experience. The optimization of all these parameters can also offer gain in energy use. In this thesis,we propose a concrete versatile dynamic solution performing an optimization of user association and resource allocation in LTE cellular networks maximizing a certainnet work utility function that can be adequately chosen. Our solution, based on gametheory, permits to compute Cell Individual Offset and a pattern of power transmission over frequency and time domain for each cell. We present numerical simulations toillustrate the important performance gain brought by this optimization. We obtain significant benefits in the average throughput and also cell edge user through put of40% and 55% gains respectively. Furthermore, we also obtain a meaningful improvement in energy efficiency. This work addresses industrial research challenges and assuch, a prototype acting on emulated HetNets traffic has been implemented
Camus, Manuel. "Architecture de réception RF très faible coût et très faible puissance : application aux réseaux de capteurs et au standard ZigBee". Phd thesis, Université Paul Sabatier - Toulouse III, 2008. http://tel.archives-ouvertes.fr/tel-00309926.
Texto completo da fonteHaouari, Lobna. "MODELISATION ET SIMULATION DE L’INTRODUCTION DE TECHNOLOGIES RFID DANS DES SYSTEMES DE CONFIGURATION A LA DEMANDE". Thesis, Saint-Etienne, EMSE, 2012. http://www.theses.fr/2012EMSE0680/document.
Texto completo da fonteRadio Frequency IDentification allows quick and secure identification of objects. In mass customisation systems, RFID technologies can be peculiarly efficient, because they are able to support the complex flows of information which characterize these systems.In this study, we focus on RFID technologies effects on configuration to order (CTO) systems.We base the research on an existing case in order to obtain reliable information directly usable by decision makers. The rarity of studies offering quantitative, detailed and real case based measures makes the originality of this thesis.RFID technology implementation's effect is analysed by a discrete event simulation approach and is presented in two levels:The first level relates direct changes brought about by RFID (e.g. faster execution of the many checks due to the wide range of products, reduced workload for resources…). These changes have an impact on system's performance in terms of lead time, late orders' rate, etc.The second level is axed on deeper changes occurring due to the increased product visibility and the ease of collecting large amounts of data with an RFID technology.These changes mainly focus on the dynamic allocation of workload. Reconsidering of processes and proposing changes deeper than the simple direct technology impact is a breakthrough, in this study, because of the lack of publications highlighting this benefit adequately.In conclusion, RFID contribution in CTO systems and, extensively, in assembly to order systems may be undeniable. Moreover, beyond the direct technology impact, rethinking how the system works by exploiting the deeper potential of technology can increase profits
Ben-Mosbah, Azza. "Privacy-preserving spectrum sharing". Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2017. http://www.theses.fr/2017TELE0008.
Texto completo da fonteRadio frequencies, as currently allocated, are statically managed. Spectrum sharing between commercial users and incumbent users in the Federal bands has been considered by regulators, industry, and academia as a great way to enhance productivity and effectiveness in spectrum use. However, allowing secondary users to share frequency bands with sensitive government incumbent users creates new privacy threats in the form of inference attacks. Therefore, the aim of this thesis is to enhance the privacy of the incumbent while allowing secondary access to the spectrum. First, we present a brief description of different sharing regulations and privacy requirements in Federal bands. We also survey the privacy-preserving techniques (i.e., obfuscation) proposed in data mining and publishing to thwart inference attacks. Next, we propose and implement our approach to protect the operational frequency and location of the incumbent operations from inferences. We follow with research on frequency protection using inherent and explicit obfuscation to preserve the incumbent's privacy. Then, we address location protection using trust as the main countermeasure to identify and mitigate an inference risk. Finally, we present a risk-based framework that integrates our work and accommodates other privacy-preserving approaches. This work is supported with models, simulations and results that showcase our work and quantify the importance of evaluating privacy-preserving techniques and analyzing the trade-off between privacy protection and spectrum efficiency
Ben-Mosbah, Azza. "Privacy-preserving spectrum sharing". Thesis, Evry, Institut national des télécommunications, 2017. http://www.theses.fr/2017TELE0008/document.
Texto completo da fonteRadio frequencies, as currently allocated, are statically managed. Spectrum sharing between commercial users and incumbent users in the Federal bands has been considered by regulators, industry, and academia as a great way to enhance productivity and effectiveness in spectrum use. However, allowing secondary users to share frequency bands with sensitive government incumbent users creates new privacy threats in the form of inference attacks. Therefore, the aim of this thesis is to enhance the privacy of the incumbent while allowing secondary access to the spectrum. First, we present a brief description of different sharing regulations and privacy requirements in Federal bands. We also survey the privacy-preserving techniques (i.e., obfuscation) proposed in data mining and publishing to thwart inference attacks. Next, we propose and implement our approach to protect the operational frequency and location of the incumbent operations from inferences. We follow with research on frequency protection using inherent and explicit obfuscation to preserve the incumbent's privacy. Then, we address location protection using trust as the main countermeasure to identify and mitigate an inference risk. Finally, we present a risk-based framework that integrates our work and accommodates other privacy-preserving approaches. This work is supported with models, simulations and results that showcase our work and quantify the importance of evaluating privacy-preserving techniques and analyzing the trade-off between privacy protection and spectrum efficiency