Bakgrund: Vid medelåldern drabbas många individer av muskuloskeletala sjukdomar som kan förebyggas och rehabiliteras genom styrketräning. Studier har gjorts på vad som motiverar människor till fysisk aktivitet men är bristfällig gällande motivation till styrketräning. Syfte: Syftet med studien var att undersöka vilka faktorer som motiverar styrketränande personer i medelåldern till att styrketräna, samt att redogöra för hur kön, grupp- och individuell träning, träningsvolym och hur länge en person styrketränat påverkar motivationsfaktorerna. Metod: Femtiofem personer mellan 40-60 år besvarade ett digitalt frågeformulär om vad som motiverar dem till att styrketräna. En del av enkäten innehöll bakgrundsfrågor om deltagarna. Den andra delen innefattade en modifierad version av formuläret RM 4-FM. Resultat: Deltagarna drevs främst av inre motivation och identified regulation. Det fanns en signifikant skillnad i typ av motivation mellan könen, där kvinnorna skattade högre på frågor gällande identified regulation (p=.028). Det fanns ingen signifikant skillnad mellan personer som tränade individuellt eller i grupp (external regulation: p=.500, introjected regulation: p= .517, identified regulation: p=.391, intrinsic regulation: p=.918) och inget samband mellan antal tränade timmar per vecka (p=.109) eller hur länge en person har styrketränat (p=.663) med relative autonomy index (RAI. Konklusion: Resultaten ger insikt i att personer i medelåldern drivs mer av inre motivation till styrketräning och att kvinnor tenderar att motiveras mer av inre drivkrafter, men kan inte generaliseras till hela populationen. Fortsatt forskning krävs för att undersöka relationen mellan motivation och styrketräning hos personer i medelåldern. / Background: During the middle-age, it is common to obtain a variety of musculoskeletal conditions, however, strength training reduces the risk to obtain these complications. There are many studies with the goal to research motivational factors that contribute to physical activity, however, there are few studies that have similar objectives related to strength training.  Objective: The objective of this study was to better understand what motivates middle aged individuals to strength train.  Method: In this study, 55 participants between 40 to 60 years old, completed a questionnaire about motivational factors to strength training. The first part consisted of background questions and the second part, a modified version of the RM 4-FM questionnaire.  Results: The results from the questionnaire showed that a majority of the sample were driven by intrinsic motivation and more specifically identified regulation. Group comparisons showed that women on average scored higher on the questions related to identified regulation (p=.028). There were no significant differences between individuals who train individually or in group (external regulation: p=.500, introjected regulation: p= .517, identified regulation: p=.391, intrinsic regulation: p=.918) nor seen in correlation between training volume (p=.109) and training experience (p=.663) with RAI. Conclusion: The results of this study show that individuals who strength train are predominantly incentivised by intrinsic motivation and women tend to have a stronger intrinsic motivation than men, however further research is required to continue to explore the complex relationship between motivation and strength training habits.

Logging of cores of the Upper Permian and Lower Triassic Khuff Formation, Ghawar, Saudi Arabia, has allowed a high resolution sequence stratigraphic framework to be generated. The lithofacies of this huge, arid epeiric ramp succession include: subaqueous -and supratidal anhydrite, tidal flat laminites, lagoonal mudstone, ooid-peloid grainstone, and subtidal off-shoal open marine mudstone. Third order sequences include the Late Permian upper Khuff C, the Early Triassic Khuff B and the Khuff A sequences, which corrrelate with global cycles. Seven high frequency sequences (HFSs) make up the Changhsingian upper Khuff C. These HFSs are ~400 k.y. duration and probably driven by long term eccentricity. The Early Triassic Khuff B and A sequences are made up of 4 HFSs each, which appear to be ~100 to 200 k.y. duration and not easily tied to eccentricity forcing. The HFSs are in turn composed of parasequences, which appear to be 10 to 20 k.y. average durations, suggesting precessional and half precessional forcing. However, many thin locally developed cycles may be autocycles or subprecessional cycles. Sequence stratigraphic cross sections and facies maps document progradation directions on the platform, reflecting the subtle interplay between the Ghawar structure and regional paleoslopes. Anhydrites are rare in the Permian Upper Khuff C except near the base of the studied interval. Anhydrites are well developed in the Triassic Khuff B and Khuff A where some form transgressive deposits while others are highstand deposits of high frequency sequences. The Permian-Triassic boundary (PTB) on the Arabian Platform marks a significant relative sea-level drop, that exposed from the outcrop belt to somewhere east of Ghawar. This contrasts with transgressive PTB settings elsewhere. Across the PTB the mass extinction is marked by a major decrease in biotic groups. The extinction was followed by development of subtidal thrombolites and increased microbial calcification due to decreased bioskeletonization. The dominant reservoirs in the Permian Upper Khuff C occur in oolite in the uppermost high frequency sequence. In the Triassic Khuff B and A the reservoir facies are commonly non-dolomitized oolitic facies associated with open lagoon carbonates distant from evaporitic tidal flats. Within dolomitized units, best reservoirs are associated with oomoldic porosity, but oolite units proximal to evaporitic tidal flats have porosity plugged by anhydrite. Carbon and oxgyen isotope profiles up to 150 m long were obtained from cored wells of the Khuff Formation, Ghawar Field, Saudi Arabia, across the Permian-Triassic boundary. Major global excursions are at the Changhsingian-Wuchiapingian boundary and the Permian-Triassic boundary, but several smaller excursions also appear to correlate with excursions elsewhere. The presence of the negative C-isotope excursions globally in both δ¹³Ccarbonate and δ¹³C organic as well as in deeper water sections lacking emergence surfaces, strongly supports the idea of these excursions being global phenomena related global C cycling. Over 75% of the negative carbon isotope excursions in Ghawar occur beneath emergence surfaces, including the two major excursions at the Wuchiapingian and Changhsingian stage boundaries. The δ¹³C profiles beneath the boundaries resemble those iii associated with early diagenesis associated with isotopically light soil gas. The δ¹⁸O profiles beneath the surfaces are variable, perhaps reflecting variable effects of evaporation on the meteoric input, mixing or overprinting by burial diagenesis. This suggests that the C-isotope excursions on the Arabian Platform, although global in origin, appear to have been modified by early diagenesis. U depletion across the boundary is compatible with the postulated origins of the PTB event with bottom waters becoming stagnant and reducing, as a result of warming induced by volcanogenic CO₂ released by Siberian trap volcanism, methane release from thermal metamorphism of coals and destabilization of clathrates in the deep sea due to ocean warming. The global extent of the C-isotope and U excursions provides a high resolution correlation tool for Late Permian and Early Triassic successions. / Ph. D.

The wireless communications industry has experienced tremendous growth worldwide in the past decade. Numerous cellular communication systems have been developed to meet this need. In North America, AMPS, IS-54, 1S-95 and GSM are the most popular cellular systems ruling the market. In developing nations, Wireless Local Loop (WLL) services will be in great demand in the coming years. While some service providers may adapt existing cellular standards to this application, WLL does not require the support for mobility which is available in a full cellular system. As a result, substantial cost savings may be obtained through dedicated WLL implementations. In this thesis, a new wireless communication system is investigated. The system combines the low cost and flexibility of analog frequency modulation with the capacity and multipath advantages of a Code Division Multiple Access (CDMA) system. This system aims to provide WLL telephone services at low cost, with wireline grade voice quality, fast infrastructure deployment and ease of planning. In this thesis, a theory for FM/CDMA system performance is established. Closed form analytical expressions of signal to multiple. access interference ratio are obtained using both upper bounds and lower bounds. The hybrid system is also optimized for the optimum combination of modulation index and processing gain. In addition, a software test-bed is developed to model different FM demodulation schemes, evaluate the tradeoff of FM modulation index versus CDMA processing gain and the system robustness, compare the forward link and the reverse link system performance and investigate the effect of power control schemes. / Master of Science

Utilizing Building Information Modeling (BIM) for Facility Management (FM) can reduce interoperability costs during the Operations and Maintenance (OandM) phase by improving data management. However, there are technological, process related, and organizational barriers to successful implementation of BIM integrated FM (BIM-FM), and process related barriers might be solved by the use of BIM integrated FM (BIM-FM) guidelines. However, the guidelines need to be updated with lessons learned from actual practices in order to maintain their validity. In order to diagnose current practices and identify key differences between prescriptive representations and actual practices, this exploratory research compares BIM component data requirements between guidelines and actual practices at public higher education institutions in Virginia. The gap in BIM component data requirements between the guidelines and the actual practices may prevent successful implementation of BIM-FM. This research is composed of three parts: a synthesis of prescriptive representations, determination of actual data requirements in practice, and comparison of differences between guidelines and practices. Document analysis and case study via document analysis and in-person interviews were conducted to collect data. Then, direct comparison was conducted to test the research question. Though the researcher disapproved the established hypothesis of 'There would be some differences in BIM component data requirements between prescriptive representations and actual practices' due to the difference in level of information and details between prescriptive representations and actual practices, this exploratory research provides useful information. / Master of Science

The use of fingerprints for personal identification has been around for thousands of years (first established in ancient China and India). Fingerprint identification is based on two basic premises that the fingerprint is unique to an individual and the basic characteristics such as ridge pattern do not change over time. Despite extensive research, there are still mathematical challenges in characterization of fingerprints, matching and compression. We develop a new mathematical model in the spatial domain for globally modeling loop pattern fingerprints. Although it is based on the well-known AM-FM (amplitude modulation and frequency modulation) image representation, the model is constructed by a global mathematical function for the continuous phase and it provides a flexible parametric model for loop pattern fingerprints. In sharp contrast to the existing methods, we estimate spatial parameters from the spectral domain by combining the exact values of frequencies with their orientations perpendicular to the fingerprint ridge flow. In addition, to compress fingerprint images and test background Gaussian white noise, we propose a new method based on periodogram spacings. We obtain the joint pdf of these m-dependent random variables at Fourier frequencies and derive the asymptotic distribution of the test statistic.

L’ouverture du secteur audiovisuel camerounais a consacré l’avancée du processus d’acquisition et de l’octroi des libertés individuelles commencé autour des années 1990. Le décret d’application d’avril 2003 a entériné une dizaine d’années plus tard, le dispositif enclenché par la loi n°90-052 du 19 décembre 1990 relative à la liberté de communication sociale. Depuis lors, organes de presse et audiovisuels se côtoient et se heurtent à des pesanteurs susceptibles de limiter leur efficacité, en tant qu’outils et moyens de communication de proximité. Leur jeunesse, les problèmes endogènes et exogènes au paysage médiatique camerounais justifierait une étude sur l’existence et la manière dont les organes de communication sociale produisent et diffusent informations et nouvelles en direction des populations ciblées. A ce sujet, la radio communautaire, tout en cherchant à les impliquer et à les faire participer à cet objectif de communication sociale, promeut par ses programmes, la propre image des populations à laquelle elle est destinée. Il ne reste qu’à garantir les modalités pratiques, les conditions nécessaires pour une participation transparente des différents acteurs à la gestion et au fonctionnement de la radio. Pour une grande part, les populations sont prêtes à soutenir les projets de radios communautaires qui s’installent dans les localités. Les différentes techniques d’appropriation et d’usage des médias permettent d’appréhender de l’extérieur les différents enjeux qui se tissent. Elles permettent d’observer les pratiques mises en place et les conditions d’engagement des acteurs sociaux pour garantir, une longue vie à la radio. / The opening of the Cameroonian audiovisual sector dedicated the overhang of the process of acquisition and the granting of the personal freedoms begun around 1990s. The application decree of April, 2003 confirmed a decade later, the plan engaged by the law 90/052 of December 19th, 1990 relative to the freedom of social communication. Since then, newspapers and broadcasting mix and come up against gravities susceptible to limit their efficiency, as tools and means of communication of nearness. Their youth, the endogenous and exogenous problems in the Cameroonian media landscape justify a study on the existence and the way the organs of social communication produce and broadcast information and news in the direction of the targeted populations. For this subject, the community radio, while trying to imply them and to make them participate in this objective of social communication, promotes by its programs, the own image of the populations for which is intended. It remains only to guarantee the practical methods, the necessary conditions for a transparent participation of the various actors in the management and in the functioning of the radio. Mostly, the populations are ready of supporting the projects of community radios which settle down in villages. The various techniques of appropriation and uses of the media allow dreading from the outside the various stakes which weave. They allow observing the organized practices and the conditions of commitment of the civil society to guarantee, a long life on the radio.

Ce travail de thèse concerne le traitement d’image fDOT (fDOT pour fluorescence diffuse optical tomography) suit vers deux axes. Le recalage d'images fDOT à l’aide de l’imagerie TEP (tomographie par émission de positons) et l’amélioration des reconstructions fDOT à l’aide de miroirs pour collecter des projections complémentaires. Il est présenté en deux parties : Dans la première partie, une méthode automatique pour recaler les images de fDOT avec les images de Tomographie par Emission de Positons (TEP) développée dans le but de corréler l’ensemble des informations issues de chaque modalité. Cette méthode de recalage est basée sur une détection automatique de marqueurs fiduciaires présents dans les deux modalités. La particularité de cette méthode est l’utilisation de l’image de surface obtenue en fDOT, qui sert à identifier la position en Z des marqueurs fiduciaires dans les images optiques. Nous avons testé cette méthode sur un modèle de souris porteuses de xénogreffes de tumeurs de cellules cancéreuses MEN2A qui imitent un carcinome thyroïdien médullaire humain, après une double injection de traceur radioactif : [18F]2-fluoro-2-Deoxy-D-glucose (FDG) pour l’imagerie TEP et un traceur optique d’infrarouge fluorescent, le Sentidye. Grâce à la précision de notre méthode, nous arrivons à démontrer que le signal Sentidye est présent à la fois dans la tumeur et les vaisseaux environnants [1]. La qualité des images fDOT est dégradée selon l’axe Z du fait d’un nombre limité de projections pour la reconstruction. Dans la deuxième partie, le travail s’est orienté vers une nouvelle méthode de reconstruction d’images fDOT à partir d’un nouveau système d’acquisition multi-angulaire avec deux miroirs placés de chaque côté de l’animal. Ce travail a été mené en collaboration avec le département CS d’University College London (UCL), partenaire du projet Européen FMT-XCT. Le logiciel TOAST développé par cette équipe a été utilisé comme source pour l’algorithme de reconstruction, et modifié pour s’adapter à notre problématique. Après plusieurs essais concernant l’ajustement des paramètres du programme, nous avons appliqué cette méthode sur un fantôme réaliste des tissus biologiques et chez la souris. Les résultats montrent une amélioration de l’image reconstruite d’un fantôme semi-cylindrique et de l’image de rein chez la souris, pour lesquelles la méthode des miroirs est supérieure à la méthode classique sans miroir. Malgré tout, nous avons observé que les résultats étaient très sensibles à certains paramètres, d’où une performance de reconstruction variable d’un cas à l’autre. Les perspectives futures concernent l’optimisation des paramètres afin de généraliser l’approche multi-angle. / This thesis concerns the image processing of fluorescence diffuse optical tomography (fDOT), following two axes: FDOT image co-registration with PET (positron emission tomography) image and improvement of fDOT image reconstructions using mirrors to collect additional projections. It is presented in two parts:In the first part, an automatic method to co-register the fDOT images with PET images has been developed to correlate all the information from each modality. This co-registration method is based on automatic detection of fiducial markers (FM) present in both modalities. The particularity of this method is the use of optical surface image obtained in fDOT imaging system, which serves to identify the Z position of FM in optical images. We tested this method on a model of mice bearing tumor xenografts of MEN2A cancer cells that mimic a human medullary thyroid carcinoma, after a double injection of radiotracer [18F] 2-fluoro-2-Deoxy-D-glucose ( FDG) for PET imaging and optical fluorescent infrared tracer Sentidye. With the accuracy of our method, we can demonstrate that the signal of Sentidye is present both in the tumor and surrounding vessels.The fDOT reconstruction image quality is degraded along the Z axis due to a limited number of projections for reconstruction. In the second part, the work is oriented towards a new method of fDOT image reconstruction with a new multi-angle data acquisition system in placing two mirrors on each side of the animal. This work was conducted in collaboration with the CS Department of University College London (UCL), a partner of the European project FMT-XCT. TOAST software developed by this team was used as source code for the reconstruction algorithm, and was modified to adapt to the concerned problem. After several tests on the adjustment of program parameters, we applied this method on a phantom that simulating the biological tissue and on mice. The results showed an improvement in the reconstructed image of a semi-cylindrical phantom and the image of mouse kidney, for which the reconstruction of the mirrors geometry is better than that of conventional geometry without mirror. Nevertheless, we observed that the results were very sensitive to certain parameters, where the performance of reconstruction varies from one case to another. Future prospectives concern the optimization of parameters in order to generalize the multi-angle approach.

Dans le contexte de la fusion par confinement inertiel (FCI), le lissage optique est une technique utilisée pour obtenir une irradiation laser aussi homogène que possible, en modifiant les propriétés de cohérence temporelle et spatiale des faisceaux laser. L'utilisation du lissage optique est une nécessité sur les lasers de puissance comme le Laser MégaJoule (LMJ) pour limiter le développement des instabilités paramétriques issues de l'intéraction laser-plasma, et parmi elles, la rétrodiffusion Brillouin stimulée (RBS). Ces instabilités entraînent des défauts d'irradiation sur cible et peuvent aussi être une source d'endommagement dans la chaîne optique. Cependant ces techniques peuvent entraîner d'autres problèmes au niveau de la chaîne laser, tels que la conversion de modulation de phase en modulation d'amplitude (FM-AM), néfastes au bon déroulement des expériences et pouvant également endommager les chaînes laser.On comprend donc qu'il est nécessaire de trouver un compromis autour du lissage optique. L’évolution du compromis du lissage est cependant compliquée car la quantification des gains et des pertes est très difficile à établir. Ainsi, tant que la quantification n’est pas faite, le compromis n’évolue pas : le lasériste souhaite toujours moins de lissage et « l’expérimentateur » toujours plus de lissage mais aucun des deux ne peut apporter suffisamment d’éléments quantitatifs pour faire pencher la balance. Cette thèse propose donc de poser les premières briques permettant d'arriver à ce compromis pour le LMJ, à l'aide d'études théoriques et numériques.Nous comparons soigneusement le lissage longitudinal (LSSD) et transversal (TSSD) par dispersion spectrale dans une configuration de lissage idéale pour chaque cas. Avec des codes 3D, nous avons simulé la RBS dans un plasma d'or, typique des expériences de FCI et favorable au développement de la RBS. Nous montrons que, contrairement aux idées reçues, l'évolution temporelle de la RBS présente certaines différences entre les deux systèmes de lissage. Premièrement, les valeurs asymptotiques des niveaux de saturation ne sont pas tout à fait les mêmes. Avec une simple description des rayons et le calcul du gain RBS pour chaque rayon, nous avons pu expliquer cette différence. En outre, la dynamique de la RBS est également quelque peu différente. Nous avons montré que la dynamique RBS est déterminée par l'évolution temporelle des propriétés des surintensités et en particulier par la longueur d'interaction effective entre la lumière rétrodiffusée Brillouin et les points chauds. Cette longueur d'interaction effective dépend à la fois de la vitesse longitudinale et de la longueur des points chauds. En effet, la synchronisation des longueurs d'interaction effectives des deux schémas de lissage synchronise également la croissance des courbes de rétrodiffusion avant saturation.Nous montrons, également qu'il est possible de faire évoluer les paramètres de lissage du LMJ en illustrant une nouvelle façon de réduire la conversion FM-AM inévitablement présente dans les lasers de forte puissance. En répartissant le spectre total habituellement utilisé par un quadruplet (regroupement de 4 faisceaux), en deux parties de spectres identiques plus petits sur les faisceaux de gauche et de droite, la conversion FM en AM est considérablement réduite de 30% à 5% tout en maintenant la performance de lissage pour la RBS. Nous avons également montré que le temps de cohérence qui en résulte n'a aucun effet sur le niveau maximal de RBS atteint. De la même façon, il faudra étudier l'impact de ces évolutions sur d'autres instabilités telles que le diffusion Raman stimulée ou le transfert d'énergie par croisement de faisceaux. / In the context of inertial confinement fusion (ICF), optical smoothing is a technique used to obtain the most homogeneous laser irradiation possible, by modifying the temporal and spatial coherence properties of the laser beams. The use of optical smoothing is a necessity on high-power lasers such as the Laser Mégajoule (LMJ) to limit the development of parametric instabilities resulting from laser-plasma interaction, and among them, stimulated Brillouin backscattering (SBS). These instabilities lead to target irradiation defects and can also be a source of damage in the optical lines. However, these techniques can lead to other problems in the laser lines, such as the conversion of phase modulation to amplitude modulation (FM-to-AM), which is harmful to the proper conduct of the experiments and can also damage the laser optics.It is therefore a necessity to find a compromise around optical smoothing. The evolution of the smoothing compromise is however complicated because the quantification of gains and losses is very difficult to establish. Thus, as long as quantification is not done, the compromise does not evolve: the laserist always wants less smoothing and the experimentalist always more smoothing, but neither of them can bring enough quantitative elements to tip the balance. This thesis therefore proposes to lay the first groundwork for reaching this compromise for the LMJ, using theoretical and numerical studies.We carefully compare longitudinal (LSSD) and transverse (TSSD) smoothing by spectral dispersion in an ideal smoothing configuration for each case. With 3D codes, we simulated SBS in a gold plasma, typical of ICF experiments and favourable to the development of SBS. We show that, contrary to popular belief, the temporal evolution of SBS shows some differences between the two smoothing schemes. First, the asymptotic values of saturation levels are not quite the same. With a simple description using light rays and the calculation of the SBS gain for each ray, we were able to explain this difference. In addition, the dynamics of SBS are also somewhat different. We have shown that the SBS dynamics is determined by the temporal evolution of the properties of the hot-spots and in particular by the effective interaction length between the Brillouin backscattered light and the hot-spots. This effective interaction length depends on both the longitudinal velocity and the length of the hot-spots. Indeed, the synchronization of the effective interaction lengths of the two smoothing schemes also synchronizes the growth of the backscatter curves before saturation.We also show that it is possible to change the smoothing parameters of the LMJ by illustrating a new way to reduce the FM-to-AM conversion inevitably present in high-power lasers. By splitting the total spectrum usually used by a quadruplet (grouping of 4 beams) into two parts of smaller identical spectra on the left and right beams, the FM-to-AM conversion is significantly reduced from 30% to 5% while maintaining the smoothing performance for SBS. We have also shown that the resulting coherence time of the laser has no effect on the maximum level of SBS achieved. Similarly, the impact of these developments on other instabilities such as stimulated Raman scattering or crossed beam energy transfer will also need to be investigated.

Λαμβάνοντας υπόψη, ότι η αποδοτική σχεδίαση, αξιολόγηση και εγκατάσταση ενός ασύρματου δικτύου επικοινωνιών, απαιτούν τον ακριβή χαρακτηρισμό του καναλιού διάδοσης και ειδικότερα των διαλείψεων μικρής και μεγάλης κλίμακας, το αντικείμενο μελέτης της παρούσας Διδακτορικής Διατριβής (ΔΔ) εστιάζεται στη μοντελοποίηση των διαλείψεων με νέα γενικότερα στατιστικά μοντέλα και απαρτίζεται από τρεις θεματικές ενότητες που αφορούν α) μοντέλα παρουσία συνιστώσας Οπτικής Επαφής (ΟΕ), β) μοντέλα που χαρακτηρίζονται από απουσία συνιστώσας ΟΕ καθώς και γ) χρήσιμες στατιστικές εκφράσεις για τη περιγραφή του τυχαίου θορύβου FM και της μέσης χωρητικότητας του καναλιού για μερικά από τα νέα κανάλια (α-μ, α-η-μ, α-κ-μ και α-λ-η-μ). Με βάση την υφιστάμενη διεθνή βιβλιογραφία, οι κατανομές που περιγράφουν κανάλια διαλείψεων δεν είναι αρκετά ευέλικτες και πολλές φορές είναι ανεπαρκείς για τη προσαρμογή αυτών σε δεδομένα προερχόμενα από πειραματικές μετρήσεις της έντασης ανά μονάδα επιφάνειας του ηλεκτρομαγνητικού πεδίου, τόσο για κανάλια εσωτερικών, όσο και για κανάλια υπαίθριων (εξωτερικών) χώρων. Έτσι, αρχικά δίδεται ο φυσικός μηχανισμός για την ερμηνεία κάθε νέου παρουσιαζόμενου μοντέλου. Χρησιμοποιώντας το μαθηματικό φορμαλισμό που προκύπτει από την μοντελοποίηση του ασύρματου καναλιού μέσω διαφόρων μιγαδικών Gaussian διεργασιών με διαφορετικές ιδιότητες, παρέχονται χρήσιμες εκφράσεις για την περιγραφή και αξιολόγηση των ψηφιακών συστημάτων επικοινωνιών που λειτουργούν σε περιβάλλοντα διαλείψεων. Στη συνέχεια, παρουσιάζεται η μελέτη που αφορά μοντέλα που υποθέτουν ότι η συνιστώσα πολυδιόδευσης συνυπάρχει με συνιστώσα. Έπειτα, πραγματοποιείται μελέτη μοντέλων που λειτουργούν σε συνθήκες διαλείψεων, όπου δεν υφίσταται συνιστώσα ΟΕ. Στη συνέχεια της ΔΔ, αναφορικά με κάποια από τα μοντέλα που παρουσιάστηκαν, πραγματοποιείται μελέτη και διερεύνηση του τυχαίου θορύβου FM και της Μέσης Χωρητικότητας του Καναλιού (ΜΧΚ). / The effective design, assessment, and installation of a wireless radio network require an accurate characterization of the propagation channel and, in particular, the small and large scale fading. By taking this into consideration, the subject of this Philosophy Diploma (PhD) dissertation is summarized in the characterization of fading with new more general statistical models and it is composed from three thematic units that concern: a) models under LOS conditions, v) models that are characterized by lack of a LOS component as well as c) useful statistical expressions for the description of random noise FM and average channel capacity for some of the new channels. A important amount of scientific work shows that the existing distributions are not enough flexible and many times are insufficient for the adaptation in data coming from experimental measurements of intensity per unit of surface of the electromagnetic field for both indoor and outdoor channels. Based on this fact, the objective of the Thesis was the production of new more general models with always natural background. Thus, initially, the natural mechanism is given for the interpretation of each new presented model. Using the mathematic formalism that results from the modelling of wireless channel via various complex Gaussian processes with different attributes, useful expressions are provided for the description and evaluation of digital communication systems that operate in fading environments. Consequently, initially, the basic theoretical background is presented that is rendered useful and essential for the study of fading channels. Next, a study is presented that concerns models that assume that the mulitpath part coexists with a LOS component. Then, a study of models, which assume NLOS conditions, takes place. In the next part of the PhD, in regard to some of the presented models, a study of random noise FM and ACC takes place.

Översvämningar till följd av intensiva nederbördstillfällen har de senaste åren ökat i antal och omfattning. Dessa händelser förväntas bli vanligare i framtiden och skapa fler översvämningar. Med anledning av detta är det intressant att undersöka hur översvämningar i framtiden breder ut sig och vilka vattennivåer som bildas med förväntad nederbörd. Att modellera översvämningar kräver data som i vissa fall kan vara både tidskrävande och omständig att införskaffa. Möjliga avgräsningar och antaganden i modellparametrar kan då vara intressanta att göra som fortfarande ger användbara resultat. En skyfallskartering har genomförts med 2D-hydraulisk modellering i Kumla med programvaran MIKE 21 Flow Model FM. De översvämningskartor som skapades användes för att identifiera områden i Kumla som riskerar att drabbas av höga vattennivåer till följd av skyfall motsvarande 100- och 200-årsregn. En stor osäkerhet vid modellering av översvämningar är att validera resultaten som fås fram. Ofta saknas information om tidigare översvämningar. De nederbördstillfällen som används är ofta så stora att det saknas data om liknande händelser tidigare. Vid översvämningsmodellering anväds data som beskriver olika typer av modellparametrar. Dessa kommer med ytterligare osäkerheter som kan göra valideringen problematisk. För att undersöka hur stor effekt olika modellparametrar har på resultatet genomfördes en känslighetsanalys där differenskartor skapades mellan undersökta scenarion och referenskartor. Skyfallskarteringen visade att stora delar i Kumla drabbas av översvämningar för både ett 100- och 200-årsregn. Området Kumlaby identifierades som känsligt och får höga vattennivåer. Detta beror mest troligt på omgivningens topografi och att Kumlaby underlagras av leror med låg infiltrationskapacitet. I känslighetsanalysen identifierades markens råhet och infiltrationskapacitet vara styrande parametrar för översvämningens utbredning och vattennivåer. Dessa påverkar främst hur höga vattenflöden som uppstår och översvämningens utbredningen och vattennivåer. Kunskap om dessa parametrar är viktigt för att undvika över- eller underskattning av en översvämning. Användningen av avrinningskoefficienter istället för markens råhet, infiltrationskapacitet och evaporation undersöktes. Differensen i översvämningens utbredning och vattennivåer blev stor i och utanför Kumla tätort. På mindre områden kan det vara mer lämpligt att använda en avrinningskoefficient när en mer detaljerad klassning kan göras av de markytor som finns. Ett scenario som undersöktes i känslighetsanalysen var installation av gröna tak på alla byggnader i Kumla. Simuleringarna som genomfördes visade att både utbredningen och vattennivåer minskade. Detta till följd av större lagringskapacitet och motstånd mot vattenflöden som kommer med gröna tak. / Urban floods caused by intense rainfall have occurred more frequently the last couple of years. These rainfall events are expected to become more common in the future and create more floods in urban areas. This makes it important to investigate the extent and water levels from urban floods in the future. In order to simulate floods, different types of data is needed. This data can be both time consuming and difficult to obtain. With this in mind, it is interesting to investigate possible simplifications and assumptions of model parameters. A cloud burst mapping was made with 2D hydraulic modelling in Kumla with the software MIKE 21 Flow Model FM. The flood maps created were used to identify areas in Kumla which have a higher risk of being subject to high water levels. One uncertainty while modelling urban floods is the process of validating the results. There is often a lack of data for the used rainfall events or information from previous floods in the area. In flood modelling data is used which describes different model parameters, these comes with additional uncertainties and can make the validation more difficult. A sensitivity analysis was made to be able to examine effects on the results from variations in model parameters. The cloud burst mapping showed that large parts of Kumla will be affected by water levels which goes up to 1 m. The area Kumlaby was identified as being sensitive for high water levels. This is due to placement of Kumlaby below higher ground which causes water to flow toward Kumlaby. The ground below is mostly made up of clay which has low infiltration capacity. In the sensitivity analysis the bed resistance and infiltration capacity were identified as governing parameters regarding the extent and water levels of urban floods. In order to avoid over- or underestimation of floods it is important to have knowledge about these parameters in the model area. The use of a runoff coefficient instead of bed resistance, infiltration and evaporation were examined. The difference of the resulting flood were large in the whole model area. In smaller areas a runoff coefficient could be used with better results when a more detailed description can be made of the surfaces in the area. A scenario where green roofs were assumed to have been installed on all buildings in Kumla were examined. The simulations showed that both the extent and water levels decreased. This due to the fact that green roofs have a capacity to store water and delay flows of water.