Dissertationen zum Thema „Ligne sans fin“
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Turpin, Olivier. „La ligne, l’onde, le pli dans la couleur“. Electronic Thesis or Diss., Paris 8, 2021. http://www.theses.fr/2021PA080040.
Der volle Inhalt der QuelleThis thesis focuses a body of paintings and wall paintings initiated in 2014 and continuing to the present day. It was a pivotal year when I went from figurative painting to abstract painting based on the drawing of an endless line that never intersects. The purpose of this research is to analyze this ‘line being’ that replaced the figure, organizing itself in colored waves, folds, overlays and twists. If chance secretly directs the drawing of the line on the canvas or in situ, it acts in respecting opposing forces and notions, such as emptiness and fullness, background and form, appearance and disappearance, form and formlessness. The line is thus a pictorial version of the twisting Möbius ribbon that places the front and back on the same side. It is by this principle that it becomes dynamic and generates a cosmogony within which the wave and the fold move before bursting into color. The proliferation of the biomorphic line has given rise to creative phases that constitute my field of investigation. A painting is an “X-ray of action”. How did the line change into a wave? How does the line, by means of hollowing out and “alternate overlapping,” continue its path and open up possibilities of forms and voids? How does the sliding of paint create the illusion of movement through transparency and depth? Finally, how did the dripping gesture in painting emerge as the “being” that would become color?
La, Chi Anh. „Réplication de contenu dans les réseaux sans fil mobiles“. Paris, Télécom ParisTech, 2010. http://pastel.archives-ouvertes.fr/pastel-00545009.
Der volle Inhalt der QuelleThe growth of mobile devices and network-based services nowadays has raised a timely question on how to efficiently distribute the data items to mobile users. Network applications need data as an input to process and provide information to users. Consequently, data traffic exerted by mobile devices fetching content is a drainage of mobile operators’ network resources. Mobile users are now coping with the congestion at network gateways and due to the unpredictability of human mobility, mobile service providers cannot sufficiently provision infrastructures for their customers. Content replication in this context has been proved as a good solution to enhance network performance and scalability. In this thesis, we tackle the issues of content replication in heterogeneous mobile networks. Such scheme requires us to solve two basic questions: where and how many replicas should be placed in the system. We study the solution through the lenses of facility location theory and design a distributed mechanism that reduces content access latency and avoids congestion at mobile gateways. Additionally, we consider the resource constraints of mobile devices and introduce a P2P cache-and-forward mechanism for load balancing purpose. We evaluate our mechanisms against realistic human mobility models. Finally, to address rational users who may behave selfishly in replicating content, we derive a cost model and study content replication scheme using tools akin to game theory. Based on the theoretical findings, our future work is to develop the strategies to be implemented in a practical network setting
Lefort, Romain. „Contribution des technologies CPL et sans fil à la supervision des réseaux de distribution d'électricité“. Thesis, Poitiers, 2015. http://www.theses.fr/2015POIT2253/document.
Der volle Inhalt der QuelleEstablishing a supervisory infrastructure allows a better smart management than an expensive strengthening of distribution network to respond to new constraints at the energies control (Consumption, REN, EV ...). To transmit data, Power Line Communication (PLC) technologies present an advantage in this context. In fact, it enables a superposition of High Frequency (HF) signals on electrical signal 50/60 Hz. However, electric networks have not been developed to this application because of difficult propagation conditions. This research work makes a contribution to develop a simulation platform in objective to transmit data to 1 MHz. In first time, each network element is studied singly and in second time, together, to estimate "Outdoor PLC" transmission performance. The first element studied is the networks variation in function of frequency and time. Several 24h disturbance measurements on LV customers are presented. The second element is the transformers which established connection between Medium Voltage (MV) and Low Voltage (LV). The proposed modeling method is based on a "lumped model" and a "black box model". These models are applied to a 100 kVA H61 transformer most commonly used by French distribution system operator in rural and suburban networks. The third element is the power line used in MV and LV networks. The proposed modeling method is based on a "cascaded model" from the theory of transmission line. This model is applied to one power line used in LV underground network. Each model is obtained from various impedance measurements. To complete, an introductory study on mobile radio communication is performed to remote network distribution
Bramas, Quentin. „Réseaux de capteurs sans fil efficaces en énergie“. Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066309/document.
Der volle Inhalt der QuelleA wireless sensor network is an ad-hoc network connecting small devices equipped with sensors. Such networks are self-organized and independent of any infrastructure. The deployment of a WSN is possible in areas inaccessible to humans, or for applications with a long lifetime requirement. Indeed, devices in a wireless sensor network are usually battery-powered, tolerate failure, and may use their own communication protocols, allowing them to optimize the energy consumption. The main application of WSNs it to sense the environment at different locations and aggregate all the data to a specific node that logs it and can send alerts if necessary. This task of data aggregation is performed regularly, making it the most energy consuming. As reducing the energy consumed by sensor is the leading challenge to ensure sustainable applications, we tackle in this thesis the problem of aggregating efficiently the data of the network. Then, we study lifetime evaluation techniques and apply it to benchmark existing energy-centric protocols
Bramas, Quentin. „Réseaux de capteurs sans fil efficaces en énergie“. Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066309.
Der volle Inhalt der QuelleA wireless sensor network is an ad-hoc network connecting small devices equipped with sensors. Such networks are self-organized and independent of any infrastructure. The deployment of a WSN is possible in areas inaccessible to humans, or for applications with a long lifetime requirement. Indeed, devices in a wireless sensor network are usually battery-powered, tolerate failure, and may use their own communication protocols, allowing them to optimize the energy consumption. The main application of WSNs it to sense the environment at different locations and aggregate all the data to a specific node that logs it and can send alerts if necessary. This task of data aggregation is performed regularly, making it the most energy consuming. As reducing the energy consumed by sensor is the leading challenge to ensure sustainable applications, we tackle in this thesis the problem of aggregating efficiently the data of the network. Then, we study lifetime evaluation techniques and apply it to benchmark existing energy-centric protocols
Dalla'Rosa, Alexandre. „Modélisation et optimisation de la localisation d'émetteurs dans des systèmes de communication sans fil“. Paris 11, 2007. http://www.theses.fr/2007PA112299.
Der volle Inhalt der QuelleDuring the last years, portability has been the “key” for the extraordinary expansion of the personal communication systems (PCS) in urban environments. People located anywhere, at any time, can access private and collective services, exchanging information, safely and quickly, without any fixed “wireline” connection (e. G. Bluetooth, WiFi, etc. ). One of the most important considerations in successful implementation of PCS is the indoor radio communication. For more than 10 years the indoor radio propagation channel is investigated and several tools were deployed based on two different approaches to deal with the wave propagation problem: empirical and deterministic approaches. In a few words, the main differences between these two techniques are the exactness and the waste time to build and solve a wave propagation problem. Up to now, most of the indoor PCS architectures are based on empirical approaches based on the simplicity and low computational cost. However, the evolution of the wireless systems and the associated disturbances in urban environment demands more efficient tools to guarantee an efficient expansion of PCS. In this work a technique is presented to investigate the indoor radio propagation channel and search for the optimal transmitter location. The TLM method and the Kriging technique are combined to approach an objective function in order to solve at low cost an optimization problem corresponding to an electromagnetic indoor environment prediction. The technique is applied to search the optimal transmitter location in a realistic problem
Couraud, Benoît. „Optimisation des transferts d'énergie pour les systèmes connectés : application aux systèmes RFID communiquant en champ proche à très haut débit“. Electronic Thesis or Diss., Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0572.
Der volle Inhalt der QuelleThe research work presented in this thesis provides solutions to help industrials to better design RFID readers and RFID tags that implement VHBR (Very High Bit Rate) protocols. Indeed, VHBR technology has a large drawback on the functionning of RFID tags as it lowers the energy available to supply the tag. First, this research work focuses on RFID reader design, and especially matching networks design. After describing a new way of assessing power transfer in Radio Frequency systems, it is shown that T matching networks as thoses proposed in ISO/IEC 10373-6 give the best results in terms of power transfer and signal integrity. Thus, a design method is proposed to correctly choose the three T matching network components that will optimize the power transfer and still meet the signal integrity requirements.Second, this thesis will focus on the design of RFID tags, by describing a new tag's antenna design method that optimize the energy harvested by the antenna and meanwhile reduce the power reflections between the antenna and the tag's chip. This design method is based on new explicit formula that compute a rectangular planar antenna inductance as a function of its geometric characteristics. This method showed very accurate results, and can become an interesting tool for industrials to speed up and optimize their antenna design procedure.Finally, a platform that measures RFID chip's impedance in every state of the chip has been designed, even during load modulation communication. The accuracy of this tool and its importance in order to achieve a good antenna design confer it a great usefulness
Boisbouvier, Nicolas. „Application des matériaux à Bande Interdite Photonique (BIP) pour la conception d'antennes et dispositifs associés destinés aux réseaux domestiques sans fils“. Rennes 1, 2004. http://www.theses.fr/2004REN10164.
Der volle Inhalt der QuelleAbou, Chakra Sara. „La boucle locale radio et la démodulation directe de signaux larges bandes à 26 GHz“. Paris, ENST, 2004. http://www.theses.fr/2004ENST0045.
Der volle Inhalt der QuelleThe Wireless Local Loop (WLL) is a system that uses radio signals to complete the "last mile" between the subscribers and the Public Switched Telephone Network. The frequency bands allocated to the WLL in France are around 3. 5 and 26 GHz. A loop constitued of two transcievers working at 26 GHz was simulated with the ADS software, and then implemented in the RFM laboratory at ENST. This platform receivers were using a superheterodyne architecture. In order to reduce the receiver complexity while keeping the same system performances, a homodyne receiver architecture was proposed by introducing the five-port reflectometer. The five-port demodulator is a component constitued of an interferometric circuit with two RF inputs followed by three power detectors delivering three output voltages. A circuit performing broadband direct demodulation at 26 GHz was then designed in MHIC technology. The regeneration of the I&Q signals from the three output voltages of the five-port demodulator requires a calibration procedure. Thus, an adaptative self-calibration method, including all needed synchronisation procedures, was defined in order to compensate all system distorsions and regenerate the baseband signals. The transmission of modulated signals by QPSK or 16QAM with bit rates reaching 40 Mbit/s validated the complete system. The obtained performance in term of bit error rate or sensitivity were very similar to those defined in the IEEE Standard 802. 16c of the WLL
Abou, Chakra Sara. „La boucle locale radio et la démodulation directe de signaux larges bandes à 26 GHz /“. Paris : École nationale supérieure des télécommunications, 2006. http://catalogue.bnf.fr/ark:/12148/cb409818829.
Der volle Inhalt der QuelleOubaha, Khalid. „Transport micro-ondes dans un milieu complexe vers une communication sans fil à base des circuits intégrés“. Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4061.
Der volle Inhalt der QuelleNowadays, modern wireless communication systems that are operating at high frequencies in the microwave band, are massively emerging. To avoid compact architectures of electronic systems, we explore wireless communication between printed circuits integrated into the electronic systems. Several problems encountered in these systems are related to the effect of the environment on wireless communication and the protection against adverse effects. This requires new electromagnetic simulation techniques to describe the field and the system response in these environments. Along with the microwave experiments, random matrix theory (RMT) enables to theoretically study wireless communication in complex environment.This manuscrit is diveded in three main topics:On the one hand, an illustration of the situation where all the ingredients are implemented namely, a Printed Circuit Board (PCB) with transmission lines inside a cavity. I present an experimental study, which highlights the effect of the partially reverberating environment on the crosstalk of two printed lines, as well as the currents on these lines. The latter should be taken into account to guarantee the proper functioning of the PCB.On the other hand, a chaotic reverberating chamber (CRC) was designed to statistically analyze the behavior of the transmission inside a complex environment. The international standard fix several statistical criteria with which the RC have to comply. Fulfilling all criteria guarantees that the field inside the cavity is isotropic and the field components follow a bivariate Gaussian distribution. In the electromagnetic community, this is the so-called Hill’s hypothesis. This hypothesis is typically realized when the resonance overlap is large. I have experimentally studied several statistic properties of the electromagnetic response in a CRC. The effects of the modal overlap on the reflection and the transmission distributions have been analyzed. In addition to this, we have compared the experimental distributions to numerical predictions based on Random Matrix Theory. I also verified the relation between the mean frequency spacing of the maxima and the average decay rate of the cavity predicted by Schroeder and Kuttruff for a high modal overlap in acoustic rooms.Finaly, we have developed a new method to estimate the number of uncorrelated samples (NIS) in a CRC. We have suggested a perspective for NIS estimation based on the characteristic scale of maxima dynamics as a function of the stirrer angle
Couraud, Benoît. „Optimisation des transferts d'énergie pour les systèmes connectés : application aux systèmes RFID communiquant en champ proche à très haut débit“. Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0572/document.
Der volle Inhalt der QuelleThe research work presented in this thesis provides solutions to help industrials to better design RFID readers and RFID tags that implement VHBR (Very High Bit Rate) protocols. Indeed, VHBR technology has a large drawback on the functionning of RFID tags as it lowers the energy available to supply the tag. First, this research work focuses on RFID reader design, and especially matching networks design. After describing a new way of assessing power transfer in Radio Frequency systems, it is shown that T matching networks as thoses proposed in ISO/IEC 10373-6 give the best results in terms of power transfer and signal integrity. Thus, a design method is proposed to correctly choose the three T matching network components that will optimize the power transfer and still meet the signal integrity requirements.Second, this thesis will focus on the design of RFID tags, by describing a new tag's antenna design method that optimize the energy harvested by the antenna and meanwhile reduce the power reflections between the antenna and the tag's chip. This design method is based on new explicit formula that compute a rectangular planar antenna inductance as a function of its geometric characteristics. This method showed very accurate results, and can become an interesting tool for industrials to speed up and optimize their antenna design procedure.Finally, a platform that measures RFID chip's impedance in every state of the chip has been designed, even during load modulation communication. The accuracy of this tool and its importance in order to achieve a good antenna design confer it a great usefulness
Adamou, Djibrilla Incha. „Réseaux de collecte de données pour les zones blanches étendues“. Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS457/document.
Der volle Inhalt der QuelleAlthough wide white areas are not equipped or sparsely equipped with any infrastructure (energy, roads ...), strategic human activities are being carried out such as mines, forest, pipeline... To tackle the problem of deploying sensor networks in a very large area where few infrastructures are available, we propose a network deployment algorithm which aims at efficiently linking sparse points of interest in a very wide white area. The originality of the proposed method is that it mimics the evolution of a type of mold called physarum. Secondly, we aim at overcoming the deployment problem in wide white areas by using long range communication between an aircraft and earth. The new data collection scheme he proposes is based on the use of commercial flights to collect data while they cross over an area of interest. It investigates the feasibility of such a scheme by determining the collection capacity of commercial aircraft in different locations of the desert. Finally, we mixed both solutions do repatriate data from sensors not covered by any flight to a covered data sink that relays data to the aircraft
Hijazi, Hadi. „Ultra-wideband antenna systems for in-band full-duplex applications“. Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2021. http://www.theses.fr/2021ENTA0011.
Der volle Inhalt der QuelleIn-band full-duplex technology aims to mitigate the scarcity of spectral resources by allowing two radios to communicate simultaneously in the same frequency band. The main challenge for full-duplex radios is to cancel the self-interference signals, which couple from the transmitter of one radio to its own receiver, by implementing various self-interference cancellation circuitry at the antenna, analog, and digital stages of the radio front-end. Conventional self-interference cancellation techniques were dedicated for narrowband systems and little work has been conducted to extend their performance for wideband operation. Thus, in this work, we focus on studying the wideband potential of the available cancellation techniques and implementing wideband full-duplex systems based on those techniques. The implemented systems are based on the near-field cancellation technique which uses four antennas and two baluns. The systems' merits vary from extremely wide bandwidth to higher mechanical solidity and dual-polarization, but they all can maintain a decent amount of cancellation
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.
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