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Le GNSS est actuellement présent dans de nombreux domaines et permet le positionnement et la navigation. Parmi ces domaines, l’aviation civile a besoin d’une qualité de service élevée, notamment pendant les phases de vol les plus exigeantes en termes d’intégrité, de précision, de disponibilité et de continuité. Afin de satisfaire ces exigences, toutes les sources de dégradations potentielles du service doivent être prises en compte. Les distorsions des signaux GNSS générées par la charge utile du satellite sont un exemple de problème qui doit être pris en compte par l’aviation civile. Elles peuvent se manifester de deux manières différentes: les distorsions nominales générées par les satellites en fonctionnement normal et les distorsions non nominales générées lors d’une panne de la charge utile. Tout d’abord, cette thèse aborde le problème des déformations nominales affectant les signaux GPS L1 C/A et Galileo E1C. Différentes observations sont réalisées à partir de la visualisation de la fonction de corrélation ou du signal et par l’utilisation d’antennes à haut gain et d’une antenne omnidirectionnelle. Après l’observation des distorsions nominales, cette thèse aborde le sujet des distorsions non nominales du signal. En utilisant les travaux réalisés dans le passé par l’aviation civile dans le cadre du signal GPS L1 C/A, le but est de proposer de nouveaux modèles de distorsions associés aux nouveaux signaux GPS et Galileo qui vont être utilisés par l’aviation civile après 2020. Dans cette optique, de nouveaux modèles de menace (appelés TMs) pour les nouveaux signaux (GPS L5 et Galileo E5a et E1C) sont proposés. La dernière étape de cette thèse se focalise sur l’étude d’une technique capable de protéger un utilisateur de l’aviation civile contre les TMs proposés pour les nouveaux signaux. Cette technique appelée SQM est aujourd’hui implémentée dans les systèmes GBAS et SBAS pour détecter les distorsions de la fonction de corrélation dans le cadre des signaux GPS L1 C/A. / GNSS is used nowadays in various fields for navigation and positioning including safety -of-life applications. Among these applications is civil aviation that requires a very high quality of service for the most demanding phases of flight in terms of integrity, accuracy, availability and continuity. To meet these requirements any source of potential service degradations has to be accounted for. One such example is GNSS signal distortions due to the satellite payload which can manifest in two ways: nominal distortions that are generated by healthy satellites due to payload imperfections and nonnominal distortions that are triggered by a satellite payload failure. The thesis first looks at the nominal distortions through GPS L1 C/A and Galileo E1C signals. Different types of observations are used based on correlation or chip domain visualization, and using high-gain and omnidirectional antennas. After the observation of nominal distortions, the dissertation investigates the non-nominal distortions due to the payload failure. Supported by the groundwork performed by civil aviation on signal distortion for the GPS L1 C/A signal, this dissertation aims at proposing new distortions models associated to the new GPS and Galileo signals that will be used by civil aviation after 2020. In particular, new TMs for new signals (GPS L5, Galileo E5a and Galileo E1C) are proposed. Finally, in this dissertation is built an appropriate monitor, referred to as SQM that is able to detect any distortion from the proposed TMs (for new signals) that could lead to a position integrity failure. Regarding GPS L1 C/A signal monitoring, such SQM is today implemented in GNSS augmentation systems including GBAS and SBAS. The current monitors are based on the analysis of the correlation function.

The purpose of this research is to expand the understanding of certain properties of electrodes used for electrical bioimpedance measurements. Specifically, this work investigates the acclimation effect of the skin-electrode interface contact impedance. It also attempts to study the relationship between electrode spacing and amplitude of bioimpedance pulsatile signals. It was found that as soon as dry electrodes are placed on the skin, the contact impedance exponentially decreases until it reaches a constant level. The acclimation time, time to reach a constant contact impedance, is dependent of the electrode size and frequency. Increasing the size of the electrode, as well as increasing the frequency, decreases the acclimation time. The acclimation of wet electrodes was also studied, and it was found that changes in contact impedance over time are negligible in comparison to the amount dry electrodes contact impedance change. However, the contact impedance of wet electrodes, instead of decreasing, tends to increase just slightly before reaching a steady state. Electrodes that do not carry current have contact impedance magnitudes similar to those that carried current after 60 minutes. This acclimation effect seems to be driven by the moisture level in the skin-electrode interface. As sweat and moisture build up with time when using dry electrodes, contact impedance decreases; and as the moisture in wet electrodes dries up with time, contact impedance increases. Capturing the small bioimpedance changes due to blood flow in the artery proved to be quite challenging under the circular orientation and with low levels of current injected. Only 5% of all the pulsatile data acquired had high enough quality to have a discernible pulsatile signal present on it. From the analysis of this 5% of data there were not conclusive results with regards the effect of electrode spacing on the pulsatile signal amplitude. However, the placement of the electrodes relative to the artery did seem to play a role on the pulse signal amplitude since the pulse amplitude seemed to peak when the center of the 4 electrodes was close to the artery. Pulsatile signal does not seem to be consistent throughout time; performing the same measurement 50 minutes apart sometimes resulted in the same or very similar measurements and other time the measurements were very different from each other. Despite the inconclusive results, the system for switching and selecting electrodes from an array of multiple electrodes along with the algorithm to determine the quality of the measured pulsatile signal proved to be efficient and serves as a foundation for developing a measurement system that can search and identify the the electrode configuration and placement that results in acquiring high quality signals.

During muscle contraction, electrical signals are generated by the muscle cells. The analysis of those signals is called electromyography (EMG). The EMG signal is mainly determined by physiological factors including so called central factors (central nervous system origin) and peripheral factors (muscle tissue origin). In addition, during the acquisition of EMG signals, technical factors are introduced (measurement equipment origin). The aim of this dissertation was to develop and evaluate methods to estimate physiological properties of the muscles using multichannel surface EMG (MCsEMG) signals. In order to obtain accurate physiological estimates, a method for automatic signal quality estimation was developed. The method’s performance was evaluated using visually classified signals, and the results demonstrated high classification accuracy. A method for estimation of the muscle fibre conduction velocity (MFCV) and the muscle fibre orientation (MFO) was developed. The method was evaluated with synthetic signals and demonstrated high estimation precision at low contraction levels. In order to discriminate between the estimates of MFCV and MFO belonging to single or populations of motor units (MUs), density regions of so called spatial distributions were examined. This method was applied in a study of the trapezius muscle and demonstrated spatial separation of MFCV (as well as MFO) even at high contraction levels. In addition, a method for quantification of MU synchronisation was developed. The performance on synthetic sEMG signals showed high sensitivity on MU synchronisation and robustness to changes in MFCV. The method was applied in a study of the biceps brachii muscle and the relation to force tremor during fatigue. The results showed that MU synchronisation accounted for about 40 % of the force tremor. In conclusion, new sEMG methods were developed to study muscle function and motor control in terms of muscle architecture, muscle fibre characteristics, and processes within the central nervous system.

This thesis discusses theoretical analysis of the origin of speech, introduces applications of speech technologies and explains the contemporary approach to phonetical transcription of speech recordings. Furthermore, it describes the metrics of audio recordings quality assessment, which is split into two discrete classes. The first one groups signal quality metrics, while the other one groups content richness metrics. The first goal of the practical section is to create a statistical model for accuracy prediction of machine transcription of speech recordings based on a measurement of their quality. The second goal is to evaluate which partial metrics are the most essential for accuracy prediction of machine transcription.

Kritickým prvkem biometrického systému pro rozpoznávání otisků prstů je proces snímání. Kvalita snímku totiž ovlivňuje všechny další části systému počínaje zpracováním obrazu, přes extrakci rysů až po samotné rozhodnutí. Přestože bylo navrženo několik metod určování kvality snímku, chybějící formální specifikace kvality otisku nedovoluje ověřit jejich přesnost. Tato diplomová práce se zabývá hodnocením metod určujících kvalitu biometrického signálu otisku prstu. Popisuje jednotlivé faktory ovlivňující kvalitu spolu se současnými přístupy používanými pro její odhad. V práci je rovněž vysvětlena evaluační technika navržená za účelem porovnání schopnosti jednotlivých metod předpovědět výkon biometrického systému. Několik metod pro odhad kvality bylo implementováno a ohodnoceno touto technikou.

Made available in DSpace on 2016-04-04T18:31:33Z (GMT). No. of bitstreams: 1 Gerson Roberto Luqueta.pdf: 6509270 bytes, checksum: ca46642c2f88e2b7c6526f32ab1af762 (MD5) Previous issue date: 2012-12-06 / This present dissertation aims to propose the use of a wireless sensor network for monitoring the lethality of sterilization process in biologically contaminated materials that uses heat as a sterilizing agent, to replace a wired system. The survey also assesses if sensors could be used as monitors of the parameter in theoretical thermic lethality of the process, and therefore serves as an assistance element in decision making for releasing the materials sterilized in hospitls and laboratories. For this purpose, a platform with sensor nodes was mounted for temperature measurement process, lethality calculation and quality determination of the radio signal and is results were compared with wired commercial equipment. / A presente disserta??o tem por objetivo propor o uso de uma rede de sensores sem fio para monitora??o da letalidade de processo de esteriliza??o de materiais biologicamente contaminados que utiliza o calor como agente esterilizante, em substitui??o a um sistema com fio. A pesquisa avalia tamb?m se os sensores poder?o ser utilizados como monitores do par?metro da letalidade t?rmica te?rica do processo, e assim servirem como elemento de aux?lio na tomada de decis?o para a libera??o dos materiais esterilizados em hospitais e laborat?rios. Para tanto, uma plataforma com n?s sensores foi montada para medi??o da temperatura de processo, c?lculo da letalidade e determina??o da qualidade do sinal de r?dio e os seus resultados foram comparados com um equipamento comercial com fio.

Submitted by PPG Engenharia El?trica (engenharia.pg.eletrica@pucrs.br) on 2018-10-29T13:30:23Z No. of bitstreams: 1 TIAGO BENETTI_DIS.pdf: 5038519 bytes, checksum: 95fa8d1b367b574eee27e772a55a9a49 (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2018-10-30T17:21:55Z (GMT) No. of bitstreams: 1 TIAGO BENETTI_DIS.pdf: 5038519 bytes, checksum: 95fa8d1b367b574eee27e772a55a9a49 (MD5) / Made available in DSpace on 2018-10-30T17:27:25Z (GMT). No. of bitstreams: 1 TIAGO BENETTI_DIS.pdf: 5038519 bytes, checksum: 95fa8d1b367b574eee27e772a55a9a49 (MD5) Previous issue date: 2018-08-31 / Heart rate monitoring using Photoplethysmography (PPG) signals acquired from the individuals pulse has become popular due to emergence of numerous low cost wearable devices. However, monitoring during physical activities has obstacles because of the influence of motion artifacts in PPG signals. The objective of this work is to introduce a new algorithm capable of removing motion artifacts and estimating heart rate from pulse PPG signals. Normalized Least Mean Square (NLMS) and Recursive Least Squares (RLS) algorithms are proposed for an adaptive filtering structure that uses acceleration signals as reference to remove motion artifacts. The algorithm uses the Periodogram of the filtered signals to extract their heart rates, which will be used together with a PPG Signal Quality Index to feed the input of a Kalman Filter. Specific heuristics and the Quality Index collaborate so that the Kalman filter provides a heart rate estimate with high accuracy and robustness to measurement uncertainties. The algorithm was validated from the heart rate obtained from Electrocardiography signals and the proposed method with the RLS algorithm presented the best results with an absolute mean error of 1.54 beats per minute (bpm) and standard deviation of 0.62 bpm, recorded for 12 individuals performing a running activity on a treadmill with varying speeds. The results make the performance of the algorithm comparable and even better than several recently developed methods in this field. In addition, the algorithm presented a low computational cost and suitable to the time interval in which the heart rate estimate is performed. Thus, it is expected that this algorithm will improve the obtaining of heart rate in currently available wearable devices. / O monitoramento da frequ?ncia card?aca utilizando sinais de Fotopletismografia ou PPG (do ingl?s, Photopletismography) adquiridos do pulso de indiv?duos tem se popularizado devido ao surgimento de in?meros dispositivos wearable de baixo custo. No entanto, o monitoramento durante atividades f?sicas tem dificuldades em raz?o da influ?ncia de artefatos de movimento nos sinais de PPG. O objetivo deste trabalho ? introduzir um novo algoritmo capaz de remover artefatos de movimento e estimar a frequ?ncia card?aca de sinais de PPG de pulso. Os algoritmos do M?nimo Quadrado M?dio Normalizado ou NLMS (do ingl?s, Normalized Least Mean Square) e de M?nimos Quadrados Recursivos ou RLS (do ingl?s, Recursive Least Squares) s?o propostos para uma estrutura de filtragem adaptativa que utiliza sinais de acelera??o como refer?ncia para remover os artefatos de movimento. O algoritmo utiliza o Periodograma dos sinais filtrados para extrair suas frequ?ncias card?acas, que ser?o utilizadas juntamente com um ?ndice de Qualidade do Sinal de PPG para alimentar a entrada de um Filtro de Kalman. Heur?sticas espec?ficas e o ?ndice de Qualidade colaboram para que filtro de Kalman forne?a uma estimativa da frequ?ncia card?aca com alta acur?cia e robustez a incertezas de medi??o. O algoritmo foi validado a partir da frequ?ncia card?aca obtida de sinais de Eletrocardiografia e o m?todo proposto com o algoritmo RLS apresentou os melhores resultados com um erro m?dio absoluto de 1,54 batimentos por minuto (bpm) e desvio padr?o de 0,62 bpm, registrados para 12 indiv?duos realizando uma atividade de corrida em uma esteira com velocidades variadas. Os resultados tornam o desempenho do algoritmo compar?vel e at? mesmo melhor que v?rios m?todos desenvolvidos recentemente neste campo. Al?m disso, o algoritmo apresentou um custo computacional baixo e adequado ao intervalo de tempo em que a estimativa da frequ?ncia card?aca ? realizada. Dessa forma, espera-se que este algoritmo melhore a obten??o da frequ?ncia card?aca em dispositivos wearable atualmente dispon?veis.

The continuous growth of traffic demand driven by the brisk increase in number of Internet users and emerging online services creates new challenges for communication networks. The latest advances in Wavelength Division Multiplexing (WDM) technology make it possible to build Transparent Optical Networks (TONs) which are expected to be able to satisfy this rapidly growing capacity demand. Moreover, with the ability of TONs to transparently carry the optical signal from source to destination, electronic processing of the tremendous amount of data can be avoided and optical-to-electrical-to-optical (O/E/O) conversion at intermediate nodes can be eliminated. Consequently, transparent WDM networks consume relatively low power, compared to their electronic-based IP network counterpart. Furthermore, TONs bring also additional benefits in terms of bit rate, signal format, and protocol transparency. However, the absence of O/E/O processing at intermediate nodes in TONs has also some drawbacks. Without regeneration, the quality of the optical signal transmitted from a source to a destination might be degraded due to the effect of physical-layer impairments induced by the transmission through optical fibers and network components. For this reason, routing approaches specifically tailored to account for the effect of physical-layer impairments are needed to avoid setting up connections that don’t satisfy required signal quality at the receiver. Transparency also makes TONs highly vulnerable to deliberate physical-layer attacks. Malicious attacking signals can cause a severe impact on the traffic and for this reason proactive mechanisms, e.g., network design strategies, able to limit their effect are required. Finally, even though energy consumption of transparent WDM networks is lower than in the case of networks processing the traffic at the nodes in the electronic domain, they have the potential to consume even less power. This can be accomplished by targeting the inefficiencies of the current provisioning strategies applied in WDM networks. The work in this thesis addresses the three important aspects mentioned above. In particular, this thesis focuses on routing and wavelength assignment (RWA) strategies specifically devised to target: (i) the lightpath transmission quality, (ii) the network security (i.e., in terms of vulnerability to physical-layer attacks), and (iii) the reduction of the network energy consumption. Our contributions are summarized below. A number of Impairment Constraint Based Routing (ICBR) algorithms have been proposed in the literature to consider physical-layer impairments during the connection provisioning phase. Their objective is to prevent the selection of optical connections (referred to as lightpaths) with poor signal quality. These ICBR approaches always assign each connection request the least impaired lightpath and support only a single threshold of transmission quality, used for all connection requests. However, next generation networks are expected to support a variety of services with disparate requirements for transmission quality. To address this issue, in this thesis we propose an ICBR algorithm supporting differentiation of services at the Bit Error Rate (BER) level, referred to as ICBR-Diff. Our approach takes into account the effect of physical-layer impairments during the connection provisioning phase where various BER thresholds are considered for accepting/blocking connection requests, depending on the signal quality requirements of the connection requests. We tested the proposed ICBR-Diff approach in different network scenarios, including also a fiber heterogeneity. It is shown that it can achieve a significant improvement of network performance in terms of connection blocking, compared to previously published non-differentiated RWA and ICBR algorithms.  Another important challenge to be considered in TONs is their vulnerability to physical-layer attacks. Deliberate attacking signals, e.g., high-power jamming, can cause severe service disruption or even service denial, due to their ability to propagate in the network. Detecting and locating the source of such attacks is difficult, since monitoring must be done in the optical domain, and it is also very expensive. Several attack-aware RWA algorithms have been proposed in the literature to proactively reduce the disruption caused by high-power jamming attacks. However, even with attack-aware network planning mechanisms, the uncontrollable propagation of the attack still remains an issue. To address this problem, we propose the use of power equalizers inside the network nodes in order to limit the propagation of high-power jamming attacks. Because of the high cost of such equipment, we develop a series of heuristics (incl. Greedy Randomized Adaptive Search Procedure (GRASP)) aiming at minimizing the number of power equalizers needed to reduce the network attack vulnerability to a desired level by optimizing the location of the equalizers. Our simulation results show that the equalizer placement obtained by the proposed GRASP approach allows for 50% reduction of the sites with the power equalizers while offering the same level of attack propagation limitation as it is possible to achieve with all nodes having this additional equipment installed. In turn, this potentially yields a significant cost saving.    Energy consumption in TONs has been the target of several studies focusing on the energy-aware and survivable network design problem for both dedicated and shared path protection. However, survivability and energy efficiency in a dynamic provisioning scenario has not been addressed. To fill this gap, in this thesis we focus on the power consumption of survivable WDM network with dynamically provisioned 1:1 dedicated path protected connections. We first investigate the potential energy savings that are achievable by setting all unused protection resources into a lower-power, stand-by state (or sleep mode) during normal network operations. It is shown that in this way the network power consumption can be significantly reduced. Thus, to optimize the energy savings, we propose and evaluate a series of energy-efficient strategies, specifically tailored around the sleep mode functionality. The performance evaluation results reveal the existence of a trade-off between energy saving and connection blocking. Nonetheless, they also show that with the right provisioning strategy it is possible to save a considerable amount of energy with a negligible impact on the connection blocking probability. In order to evaluate the performance of our proposed ICBR-Diff and energy-aware RWA algorithms, we develop two custom-made discrete-event simulators. In addition, the Matlab program of GRASP approach for power equalization placement problem is implemented. / <p>QC 20120508</p>