La thèse a pour but de développer des algorithmes robustes de poursuite de phase multifréquence en environnement dégradé. L’objectif est d’élaborer de nouvelles structures pouvant opérer à des niveaux de rapport signal à bruit inférieurs aux limites des algorithmes actuellement implémentés dans des récepteurs grand public. Les problèmes de robustesse des algorithmes d’estimation de phase étant en grande partie causés par le phénomène de sauts de cycle, les différents axes de recherche se sont focalisés sur des nouvelles approches de développement de phase au sein des structures de poursuite. Pour ce faire, deux approches ont été étudiées et testées. Dans un premier temps, deux structures de poursuite monofréquence basées sur une DPLL conventionnelle ont été développées. Ces structures disposent d’un système externe de développement de phase visant à prédire et pré-compenser la sortie du discriminateur grâce à l’analyse des sorties du discriminateur ou des sorties du filtre de boucle. La réduction de la dynamique à estimer va alors permettre de réduire l’apparition des sauts de cycle se produisant au niveau du discriminateur. Par la suite, ce système de développement de phase a été adapté à la poursuite de phase multifréquence. Grâce à l’exploitation de la diversité en fréquence offerte par les signaux de navigation (i.e., de la proportionnalité des fréquences Doppler), il a été possible de mettre en place une étape de fusion de données qui a permis d’améliorer la précision de la prédiction de la sortie du discriminateur et donc d’améliorer la robustesse de la structure. Dans un second temps, les travaux de recherche se son taxés sur une nouvelle approche de poursuite de phase et de correction du phénomène de sauts de cycle basée sur une technique de filtrage Bayésien variationnel. Toujours en exploitant la diversité en fréquence des signaux de navigation, cette méthode suppose un modèle de dynamique de phase Markovien qui va imposer une certaine continuité de l’estimation et va permettre de fournir une estimation de phase développée. / This thesis aims at introducing multifrequency phase tracking algorithms operating in low C/N0environment. The objective is to develop new structures whose tracking limits are lower than thatof current algorithms used in mass market receivers. Phase tracking suffers from a lack of robustnessdue to the cycle slip phenomenon. Works have thus been focused on elaborating new phaseunwrapping systems. To do so, two different tracking approaches were studied. First, we have developed new monofrequency tracking loops based on a conventional DPLL. These structures aimat predicting the discriminator output by analyzing, thanks to a polynomial model, the last outputsamples of either the discriminator or the loop filter. Once the discriminator output is predicted,the estimated value is pre-compensated so that the phase dynamics to be tracked is reduced aswell as the cycle slip rate. Then, the unwrapping structure analyzing the loop filter outputs hasbeen extended to multifrequency signals. Using a data fusion step, the new multifrequency structuretakes advantage of the frequency diversity of a GNSS signal (i.e., proportionality of Dopplerfrequencies) to improve the tracking performances. Secondly, studies have been focused on developing a new multifrequency tracking algorithm using variational Bayesian filtering technique.This tracking method, which also uses the GNSS frequency diversity, assumes a Markovian phasedynamics that enforces the smoothness of the phase estimation and unwraps it.

The aim of this study was a prospective detection of postoperative lymphedema of the lower limbs in patients after the surgery for cervical and vulvar cancer using different methods of examination and their comparison and monitoring of postoperative complications and quality of life. Totally 78 women were followed after the surgery for cervical cancer and 36 for carcinoma of the vulva. Due to the radicality of the surgery the patients were divided into the conservative and radical groups. Lower limbs lymphedema were evaluated preoperatively and 3, 6 and 12 months after the surgery by the measurement of the lower limbs circumference, multifrequency bioelectrical impedance analysis (MFBIA) and subjective feeling. Quality of life using the European Organisation for Research and Treatment of Cancer (EORTC) questionnaires was evaluated before and 6 and 12 month after the surgery. 12 months after the cervical cancer surgery 35.9 % of patients reported subjective lymphedema, 37.18 % lymphedema were objectively diagnosed by the measurement of lower limb circuits and in 52.56 % of cases the increase of amount of extracellular fluid was detected by the MFBIA Ri/R0 method. The prevalence of lymphedema after the surgery for vulvar cancer reached 19.44% by the subjective assessment, 38.89 % by the measurement of...

The thesis deals with the proposal, implementation and evaluation of test for fault condition indicators. Thesis focusing on earth fault indicators based on admittance principles. These indicators must be able to evaluate earth faults in compensated, compensated with auxiliary resistor, unearthed and high-resistance earthed networks. The proposed tests verify the current and voltage measurement errors in inputs including monitored characteristic variables such as conductance and susceptance. The proposed test are applied to a selected ample of the fault indicator. As part of the tests, the indicator is subjected to secondary test using the Omicron CMC256plus tester as well as test on fault records that have been converted to COMTRADE for this purpose. The last series of tests carried out uses the physical model of the medium voltage system, where the tested equipment is subjected to fault states in the compensated whit auxiliary resistor system and isolated system. Furthermore, part of the thesis is research of new methods of earth fault detection, including their principles and function description. Also included in the thesis is an overview of manufacturers of indicators, or protection, who are involved in the production of earth fault protection.

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Volume overload is a common feature in patients on haemodialysis (HD). This contributes significantly to the cardiovascular disease burden seen in these patients. Clinical assessments of the volume state are often inaccurate. Techniques such as interdialytic blood pressure, relative blood volume monitoring, bioimpedance are available to improve clinical effectives. However all these techniques exhibit significant shortcomings in their accuracy, reliability and applicability at the bed side. We evaluated the usefulness of a dual compartment monitoring technique using Continuous Segmental Bioimpedance Spectroscopy (CSBIS) and Relative Blood Volume (RBV) as a tool to assess hydration status and determine dry weight. We also sought to evaluate the role of Atrial Natriuretic Peptide (ANP) and B-type Natriuretic Peptide (BNP) as a volume marker in dialysis patients. The Retrospective analysis of a historical cohort (n = 376, 55 Diabetic) showed a significant reduction in post-dialysis weights in the first three months of dialysis (72.5 to 70kg, p<0.027) with a non-significant increase in weight between months 6-12. The use of anti-hypertensive agents reduced insignificantly in the first 3 months, increased marginally between months 3-6 and significantly increased over the subsequent 6 months. The residual urea clearance (KRU) fell and dialysis times increased. The cohort was very different to that dialysing at Tassin and showed a dissociation between weight reduction and BP control. This may relate to occult volume overload. CSBIS-RBV monitoring in 9 patients with pulse ultrafiltration (pulse UF) showed distinct reproducible patterns relating to extra cellular fluid (ECF) and RBV rebound. An empirical Refill Ratio was then used to define the patterns of change and this was related to the state of their hydration. A value closer to unity was consistent with the attainment of best achievable target weight. The refill ratio fell significantly between the first (earlier) and third (last) rebound phase (1.97 ± 0.92 vs 1.32 ± 0.2). CSBIS monitoring was then carried out in 31 subjects, whilst varying dialysate composition, temperature and patient posture to analyse the effects of these changes on the ECF trace and to ascertain whether any of these interventions can trigger a change in the slope of the ECF trace distinct to that caused by UF. Only, isovolemic HD caused a change in both RBV and ECF in some patients that was explained by volume re-distribution due to gravitational shifts, poor vascular reactivity, sodium gradient between plasma and dialysate and the use of vasodilating antihypertensive agents. This has not been described previously. These will need to be explored further. The study did demonstrate a significant lack of comparability of absolute values of RECF between dialysis sessions even in the same patient. This too has not been described previously. This is likely to be due to subtle changes in fluid distribution between compartments. Therefore a relative changes must be studied. This sensitivity to subtle changes may increase the usefulness of the technique for ECF tracking through dialysis. The potential of dual compartment monitoring to track volume changes in real time was further explored in 29 patients of whom 21 achieved weight reductions and were able to be restudied. The Refill Ratio decreased significantly in the 21 patients who had their dry weights reduced by 0.95 ± 1.13 kg (1.41 ± 0.25 vs 1.25 ± 0.31). Blood pressure changes did not reach statistical significance. The technique was then used to examine differences in vascular refill between a 36oC and isothermic dialysis session in 20 stable prevalent patients. Pulse UF was carried out in both these sessions. There were no significant differences in Refill Ratios, energy removed and blood pressure response between the two sessions. The core temperature (CT) of these patients was close to 36oC and administering isothermic HD did not confer any additional benefit. Mean BNP levels in 12 patients during isovolemic HD and HD with UF did not relate to volume changes. ANP concentrations fell during a dialysis session in 11 patients from a mean 249 ± 143 pg/ml (mean ± SD) at the start of dialysis to 77 ± 65 pg/ml at the end of the session (p<0.001). During isolated UF levels did not change but fell in the ensuing sham phase indicating a time lag between volume loss and decreased generation. (136±99 pg/ml to 101±77.2 pg/ml; p<0.02) In a subsequent study ANP concentrations were measured throughout dialysis and in the post-HD period for 2 hours. A rebound in ANP concentration was observed occurring at around 90 min post-HD. The degree of this rebound may reflect the prevailing fluid state and merit further study. We have shown the utility of dual compartment monitoring with CSBIS-RBV technique and its potential in assessing volume changes in real time in haemodialysis patients. We have also shown the potential of ANP as an independent marker of volume status in the same setting. Both these techniques merit further study.