Du fait de leur compacité, leur robustesse et leur faible coût, les microlasers impulsionnels nanosecondes constituent des sources particulièrement attractives pour de nombreux systèmes de détection et d'analyse, en particulier les cytomètres en flux ou les dispositifs pour la spectroscopie CARS (Coherent Raman Anti Stokes Scattering). Cependant, ces applications nécessitent des performances améliorées en ce qui concerne la gigue temporelle et la cadence de répétition accessible. Dans sa première partie, cette thèse propose des solutions originales pour atteindre les performances requises à partir de microlasers passivement déclenchés, grâce à la mise en oeuvre d'une cavité hybride couplée, pompée par une onde modulée en intensité. Une cadence de répétition supérieure à 30 kHz avec une gigue demeurant inférieure à 200 ns est atteinte. Le potentiel de microlasers à fibres déclenchés par modulation du gain pour monter en cadence est aussi évalué, montrant que des impulsions à faible gigue, à une cadence de plus de 2 MHz peuvent être produites. Enfin, la dernière partie est consacrée à la mise au point et à l'exploitation d'un nouveau système de spectroscopie CARS assisté par une excitation électrique haute tension. Ce dispositif, réalisé à partir d'un microlaser amplifié, permet de s'affranchir du bruit de fond non résonnant des mesures et de réaliser une analyse spectroscopique fine de la réponse de différents milieux d'intérêt sous champ continu ou impulsionnel, pouvant conduire à une nouvelle méthode de microdosimétrie de champ. Diverses applications, dont la granulométrie à l'échelle micro ou nanométrique ou l'identification de marqueurs pour la biologie, sont démontrées. / Thanks to their compactness, robustness and low cost, pulsed nanosecond microlasers are particularly attractive sources for different detection and analysis systems, particularly flow cytometers or devices for CARS (Coherent Anti Raman Stokes Scattering) spectroscopy. However, these applications require reduced time jitter and increased repetition rate. The first part of this thesis proposes novel solutions to achieve the required performance from passively Q-switched microlasers, which are based on an hybrid coupled-cavity and intensitymodulated pump wave. A repetition rate greater than 30 kHz with jitter remaining lower than 200 ns is reached. Pulsed fiber microlasers operating by gain switching are also studied, showing that pulses with low timing jitter, at a repetition rate of more than 2 MHz can be obtained. The last part is devoted to the development and the implementation of a new system of CARS spectroscopy assisted by a high-voltage electrical stimulation. This device, based on an amplified microlaser, allows to substract the non-resonant background noise in the measurements. Thus, a fine spectroscopic analysis of the response of different environments of interest in continuous or pulsed field can be achieved. It may lead to a new method for field microdosimetry. Various applications, including granulometry at the micro or nanometric scale and the identification of markers for biology, are shown.

This thesis deals with the measurement of transmission parameters in the new generation access networks NGA. The aim of the thesis is to build and configure a test network and scenarios for the measurement of service quality parameters and then verify the transmission stability. The theoretical part describes general functioning of NGN networks, the requirements of different telecommunications services on quality parameters, methodology and recommendations for measuring transmission parameters in packet networks. The practical part deals with the configuration of scenarios using mainly MPLS technology and methodology of their testing. Measurements were performed according to recommendations IETF RFC 2544, IETF RFC 6349 with the ExacTCP test and ITU-T Y.1564 with the EtherSAM test. For measurements were used measuring instruments of EXFO brand. In conclusion, the measurement results according to the mentioned standards were evaluated and also the advantages of using the measurement according to the given standard in NGA access networks were discussed.

Internet of Things(IoT) tillämpningar har ökat under de senaste åren och därför behövs nya kommunikationstekniker som uppfyller kriterierna låg strömförbrukning, lång räckvidd samt låg kostnad, som behövs för att distribuera tekniken i samhället. LoRa (Long Range) är en framstående trådlös kommunikationsteknik som utvecklades av LoRa Alliance för att uppfylla dessa kriterier.  Syftet med arbetet är att utveckla en mätmetod för prestandaanalys av radiosystemet LoRa. Mätmetoden används sedan för att analysera hur olika parametrar som datahastighet, avstånd och olika miljöer påverkar LoRa-nätverksprestandaparametrar dvs. signalstyrka, paketförluster, fördröjningar (latency) och fördröjningsvariationer (jitter).  För att uppnå syftet utvecklades först en mätningsmetod. Därefter genomfördes experiment i två olika miljöer (stadsmiljö och havsmiljö) för prestandaanalys av LoRa. I varje experiment positionerades en IoT-nod på olika avstånd och datapaket skickades med olika datahastigheter från IoT-noden till en gateway. Datahastigheten ändrades genom att ändra på spridningsfaktor (SF) och bandbredd. Passiv mätningsmetod användes för att samla in mätningsdata. Metoden som användes för att analysera resultaten var statistisk dataanalysmetod då de data som samlades in var kvantitativa.  Resultatet visar att signalstyrkan påverkas av miljö, avstånd och bandbredd. Signalstyrkan är starkare i fri sikt jämfört med stadsmiljö. Signalstyrkan är starkare även vid kortare avstånd och större bandbredd. Däremot har datahastigheten (SF) minimal påverkan på signalstyrkan. Att signalstyrkan påverkas av bandbredden är intressant resultat som inte kunde förutses innan. Paketförlusten påverkas av miljö, datahastighet (SF och bandbredd) och avstånd. Fler datapaket förloras vid längre avstånd och i stadsmiljön. Lägre datahastighet leder till att färre datapaket förloras och på så sätt längre kommunikationsräckvidd uppnås. Enligt tidigare arbetens simuleringar förutsågs att högre datahastighet leder till längre kommunikationsräckvidd men i den här studien genomfördes experiment på riktig hårdvara för att undersöka resultaten. Miljö, avstånd och datahastighet påverkar fördröjningen. Fördröjningen är några millisekunder längre i stadsmiljö än havsmiljö vid samma avstånd. Fördröjningen är även några millisekunder längre vid längre avstånd i samma miljö. Däremot har datahastighet största påverkan på fördröjningen. Fördröjningen ändras med några hundra millisekunder när datahastigheten ändras genom SF och/eller bandbredd.  Fördröjningsvariationen påverkas inte av miljö och avstånd. Datahastighet (bandbredd och SF) påverkar fördröjningsvariationen men denna påverkan är låg och man kan bortse från den. / The Internet of Things (IoT) use cases have increased significantly in recent years. Therefore, new wireless communication technologies are needed that meet the criteria such as low power consumption, long range and low cost. LoRa, which stands for "Long Range", is a wireless communication technology developed by the LoRa Alliance to meet these criteria.  The purpose of this paper is to a develop measurement method for performance analysis of the LoRa radio system. The measurement method used to analyze how different parameters such as data rate, distance and different environments affect LoRa network performance parameters i.e. signal strength, packet loss, latency and jitter. To achieve the purpose, a measurement method and prototype were first developed. Then experiments were carried out in two different environments (urban and open space). In each experiment, an IoT node was positioned at different distances and data packets were sent from the IoT node to a gateway with different data rates. The data rate was changed by changing the spreading factor (SF) and bandwidth. Passive measurement method was used to collect measurement data. The method used to analyze the results was the statistical data analysis method since the data collected was quantitative. The result shows that the signal strength is affected by the environment, distance and bandwidth. The signal strength is stronger in free view compared to urban environment. The signal strength is stronger even at shorter distances and greater bandwidth. However, the data rate (SF) has minimal impact on signal strength. The fact that the signal strength is affected by the bandwidth is interesting results that could not be predicted before. The packet loss is affected by the environment, data rate and distance. More data packets go lost at longer distances and in the urban environment. Lower data rate cause to fewer data packets go lost and a longer communication range being achieved. According to earlier work's simulations, it was possible to predict that higher data rates lead to longer communication range, but in this study experiments were carried out on real hardware to investigate the results. Environment, distance and data rate affect the delay. The delay is a few milliseconds longer in urban environment than the free space environment at the same distance. The delay is also a few milliseconds longer at longer distances in the same environment. However, data rate has the greatest impact on the delay. The delay changes by a few hundred milliseconds when the data rate is changed by SF and/or bandwidth. The jitter is not affected by the environment and distance. Data rate (bandwidth and SF) affects the delay variation but this influence is low and can be ignored.

Video acquired using a camera mounted on a mini Unmanned Air Vehicle (mUAV) may be very helpful in Wilderness Search and Rescue and many other applications but is commonly plagued with limited spatial and temporal field of views, distractive jittery motions, disorienting rotations, and noisy and distorted images. These problems collectively make it very difficult for human viewers to identify objects of interest as well as infer correct orientations throughout the video. In order to expand the temporal and spatial field of view, stabilize, and better orient users of noisy and distorted mUAV video, a method is proposed of estimating in software and in real time the relative motions of each frame to the next by tracking a small subset of features within each frame to the next. Using these relative motions, a local Euclidean mosaic of the video can be created and a curve can be fit to the video's accumulative motion path to stabilize the presentations of both the video and the local Euclidean mosaic. The increase in users' abilities to perform common search-and-rescue tasks of identifying objects of interest throughout the stabilized and locally mosaiced mUAV video is then evaluated. Finally, a discussion of remaining limitations is presented along with some possibilities for future work.

For the last ten years, DVD-R media have played an important role in the storage of large amounts of digital data throughout the world. During this time it was assumed that the DVD-R was as long-lasting and stable as its predecessor, the CD-R. Several reports have surfaced over the last few years questioning the DVD-R's ability to maintain many of its claims regarding archival quality life spans. These reports have shown a wide range of longevity between the different brands. While some DVD-Rs may last a while, others may result in an early and unexpected failure. Compounding this problem is the lack of information available for consumers to know the quality of the media they own. While the industry works on devising a standard for labeling the quality of future media, it is currently up to the consumer to pay close attention to their own DVD-R archives and work diligently to prevent data loss. This research shows that through accelerated aging and the use of logistic regression analysis on data collected through periodic monitoring of disc read-back errors it is possible to accurately predict unrecoverable failures in the test discs. This study analyzed various measurements of PIE errors, PIE8 Sum errors, POF errors and jitter data from three areas of the disc: the whole disc, the region of the disc where it first failed as well as the last half of the disc. From this data five unique predictive equations were produced, each with the ability to predict disc failure. In conclusion, the relative value of these equations for end-of-life predictions is discussed.

Cloud gaming over mobile networks enables players to play high-resource consuming games on low-end devices with various intrinsic restrictions such as limited battery lifetime and computational capacity. For mobile cloud gaming(MCG), the remaining battery level on the device is one of the critical factors that affect the sensitivity of user satisfaction. Thus, an android application is developed to measure the energy consumption of mobile devices that measure the power consumption of the device such that the obtained values correspond with the specific network conditions and users. The collected values are studied to identify if the energy consumption of the device is impacted by the network degradation that might occur during MCG in cellular networks. Results demonstrate that the energy consumption is at its highest when packet loss is 45% at 2ms RoundTrip Time (RTT) delay. Moreover, a qualitative study on the perceived Quality of Experience (QoE) of MCG over mobile networks is conducted and its impact on the energy consumption of the device is investigated where 31 users play a cloud-based First Person Shooter (FPS) for approximately 2 hours each. The results demonstrate the existence of the relationship between energy consumption and perceived QoE whereas negates the hypothesis of the existence of the relationship between QoE and CPU resources. In addition, to make comparisons of energy consumption of MCG with online mobile gaming (OMG), another test is carried out where each user plays another non-cloud-based FPS game and it is found that MCG is more efficient than OMG under the least energy-consuming network condition (2ms RTT delay) by 33.3% and the most energy consuming network condition (45% packet loss at 2ms RTT) by 32.7% in 4G cellular network.

В данной работе представлена разработка схемы управления зеркальными антеннами 600 метрового радиотелескопа на основе цифровой обработки сигналов. Был произведен анализ диаграммы направленности радиотелескопа при цифровом методе формирования, а также оценено влияние фазовых ошибок на диаграмму направленности радиотелескопа, возникающих в процессе оцифровке аналогового сигнала на несущей частоте. Было произведено математическое моделирование и оценка влияния параметров цифровой элементной базы на характеристики диаграммы направленности радиотелескопа, предложено оборудование для построения диаграммообразующей схемы радиотелескопа. / This work contains the development of a control scheme for mirror antennas of a 600-meter radio telescope based on digital signal processing. An analysis was made of the radiation pattern of the radio telescope under the digital method of formation. The influence of phase errors on the radiation pattern of the radio telescope, which arise in the process of digitizing an analog signal at a carrier frequency, was estimated. Mathematical modeling and estimation of the effect of the parameters of the digital element base on the characteristics of the radiation pattern of the radio telescope were made, equipment for constructing a radio telescope was proposed.

No description available.

In der Dissertationsschrift wird ein neuartiges Konzept der Realisierung der Direkten Digitalen Frequenzsynthese (DDS) vorgestellt. Ausgehend von der analysierten Literatur werden das Wirkprinzip eines Standard-DDS-Synthesizer analysiert und Möglichkeiten zur Aufwandsreduktion untersucht. Ein neuartiger Ansatz zur Realisierung einer vollständig digitalen DDS ergibt sich in der Anwendung der Pulse-Output-DDS. Bei der Pulse-Output-DDS wird neben dem D/A-Wandler auch die Sinus-ROM-Tabelle aus dem prinzipiellen Aufbau der Standard-DDS entfernt. Ausgehend von einer derart modifizierten DDS-Struktur wird ein geeignetes DDS-Modell entwickelt, mit welchem alle auftretenden Synthesefehler systematisch erfaßt und bewertet werden können. Die gewonnenen Erkenntnisse über die prinzipbedingten Synthesefehler bilden die Grundlage für Erweiterungen der Pulse-Output-DDS mit deren Hilfe eine qualitative Verbesserung des synthetisierten Signals erreicht wird. Dabei steht vor allem die Anwendung von Verfahren der digitalen Signalverarbeitung im Vordergrund, die zu einer Verringerung bzw. Kompensation oder zu einer spektralen Veränderung des auftretenden DDS-Fehlersignals geeignet sind. Es werden die erreichbaren Verbesserungen, aber auch die theoretischen und praktischen Grenzen von folgenden Verfahren aufgezeigt: absolute Verringerung des DDS-Fehlersignals Dithering des DDS-Fehlersignals Rauschformung (Noise-Shaping) des Fehlersignalspektrums Insbesondere bei der Rauschformung werden unterschiedliche Ansätze untersucht und bewertet mit dem Ziel, ein optimales Verfahren für den Rauschformungsprozeß bei der Verwendung in einer Pulse-Output-DDS zu finden. Durch die echtzeitfähige Implementation eines erweiterten DDS-Systems in einem Standard-CMOS-Prozeß werden die gefundenen theoretischen Lösungen verifiziert.

In der Dissertationsschrift wird ein neuartiges Konzept der Realisierung der Direkten Digitalen Frequenzsynthese (DDS) vorgestellt. Ausgehend von der analysierten Literatur werden das Wirkprinzip eines Standard-DDS-Synthesizer analysiert und Möglichkeiten zur Aufwandsreduktion untersucht. Ein neuartiger Ansatz zur Realisierung einer vollständig digitalen DDS ergibt sich in der Anwendung der Pulse-Output-DDS. Bei der Pulse-Output-DDS wird neben dem D/A-Wandler auch die Sinus-ROM-Tabelle aus dem prinzipiellen Aufbau der Standard-DDS entfernt. Ausgehend von einer derart modifizierten DDS-Struktur wird ein geeignetes DDS-Modell entwickelt, mit welchem alle auftretenden Synthesefehler systematisch erfaßt und bewertet werden können. Die gewonnenen Erkenntnisse über die prinzipbedingten Synthesefehler bilden die Grundlage für Erweiterungen der Pulse-Output-DDS mit deren Hilfe eine qualitative Verbesserung des synthetisierten Signals erreicht wird. Dabei steht vor allem die Anwendung von Verfahren der digitalen Signalverarbeitung im Vordergrund, die zu einer Verringerung bzw. Kompensation oder zu einer spektralen Veränderung des auftretenden DDS-Fehlersignals geeignet sind. Es werden die erreichbaren Verbesserungen, aber auch die theoretischen und praktischen Grenzen von folgenden Verfahren aufgezeigt: absolute Verringerung des DDS-Fehlersignals Dithering des DDS-Fehlersignals Rauschformung (Noise-Shaping) des Fehlersignalspektrums Insbesondere bei der Rauschformung werden unterschiedliche Ansätze untersucht und bewertet mit dem Ziel, ein optimales Verfahren für den Rauschformungsprozeß bei der Verwendung in einer Pulse-Output-DDS zu finden. Durch die echtzeitfähige Implementation eines erweiterten DDS-Systems in einem Standard-CMOS-Prozeß werden die gefundenen theoretischen Lösungen verifiziert.