La modélisation de la propagation acoustique longue distance du bang sonique dans l’air nécessite de prendre en compte la complexité des phénomènes en interaction : turbulence atmosphérique, gradients de célérité du son, impédance et rugosité du sol, et propagation non-linéaire. L’évaluation des nuisances sonores, et la validation des modèles par la comparaison avec des mesures en extérieur est délicate, car les conditions atmosphériques ne peuvent être ni suffisamment contrôlées ni caractérisées de façon extensive. Une alternative est la réalisation d’expériences à l’échelle du laboratoire où le milieu de propagation, la source sonore et les récepteurs peuvent être contrôlés et caractérisés. Ce travail porte sur la propagation à travers la turbulence d’ondes dites ’en N’, de forte amplitude et de courte durée, en champ libre ou en présence d’une paroi plane, avec un gradient de célérité du son causant une ”zone d’ombre” près du sol. Les impulsions sonores sont expérimentalement générées par claquage électrique entre deux électrodes. La turbulence est créée par convection libre au-dessus d’une grille de résistances chauffées, et la zone d’ombre acoustique est obtenue au moyen d’une paroi cylindrique. La mesure est réalisée à l’aide de microphones 1/8”.Pour l’étude de la source, une technique de strioscopie a été mise en œuvre afin de déterminer la forme d’onde. Le niveau de pression doit cependant être déterminé par une analyse complémentaire, basée sur la théorie des chocs faibles avec une forme d’onde différente de l’onde en N idéale. Un des facteurs limitant des expériences à l’échelle du laboratoire est la transposition vers une gamme ultrasonore, afin que le rapport longueur d’onde - distance de propagation reste du même ordre de grandeur que pour l’atmosphère. Constatant qu’il n’existe pas de méthode de calibration adaptée dans une gamme de fréquence de 10 kHz à 1 MHz (typique des expériences à l’échelle du laboratoire), une nouvelle méthode de calibration a été proposée et appliquée avec succès. En champ libre, la turbulence thermique cause en moyenne une atténuation du pic de pression. Des zones de focalisation aléatoire existent néanmoins, où l’amplitude de l’onde est multipliée par 3. Les répartitions statistiques du pic de pression ont été décrites avec un excellent accord par une loi de probabilité de type Gamma généralisée. La présence d’une frontière peut en outre donner lieu à des réflexions irrégulières, en raison des niveaux de pression importants. Nous avons mis en évidence ce phénomène dans l’air avec une paroi plane ou cylindrique. Pour l’étude de la propagation en zone d’ombre acoustique, un résultat important de la thèse est que, contrairement à la propagation en champ libre, la probabilité que la turbulence atténue le pic de pression en zone d’ombre est nulle. Cette observation suggère qu’avec turbulence, le mécanisme dominant de propagation est la diffusion acoustique par les structures turbulentes. Ceci aurait pour conséquence dans le cas du bang sonique l’extension de la zone d’exposition sonore sous la trace de l’avion (carpette primaire). / Long range sound propagation in the atmosphere is influenced by several effects: atmospheric turbulence, sound-speed gradients, ground properties (impedance, rugosity) etc. In the context of supersonic aircraft, nonlinear propagation of the sonic boom has to be taken into account. To evaluate the influence of these different effects, a statistical analysis is needed. However, field measurements suffer from a lack of control on atmosphere characteristics, and the statistical analysis remains circumscribed by the limited number of aircraft flight tests. An alternative to outdoor measurements is to perform experiments under well-controlled laboratory conditions. These experiments allow to study the effects purely related to the turbulent layer and to the sound-speed gradient. The propagation of high amplitude and short duration N-waves through thermal turbulence is studied. In particular, the influence of a rigid boundary and a negative sound-speed gradient resulting in a shadow-zone near the boundary, are pointed out. An experimental setup has been designed : N-waves are generated using a spark source. Thermal turbulence is obtained with a grid of electrical resistors, and the shadow-zone is obtained used a curved boundary. Measurements are performed using 1/8” microphones, and a schlieren shadowgraphy technique. The real pressure waveform (different from the ideal N-wave) delivered by the spark source has been obtained using the strioscopy technique, up to a multiplicative constant. Weak-shock theory enables to estimate the pressure level under the assumption that the pressure waveform is an ideal N-wave. This method has been modified to take into account the real pressure waveform. Because of the geometrical scaling, laboratory-scale experiments lead to a shift to a higher frequency domain : typically, 10 kHz – 1 MHz. In this frequency range, no calibration method is available up to now. A new method has been proposed and successfully applied. Free-field propagation of high-amplitude N-waves through the turbulent layer leads to a mean attenuation of the pressure level. However, random focus of the pressure waves can be observed, up to factor of 3. Probability densities of the shock overpressure have been described with an excellent agreement by a generalized Gamma probability distribution. With a rigid boundary, irregular reflections of shockwaves can be observed because of the high pressure level. This type of irregular reflections has been outlined either with a plane or a cylindrical boundary. Propagation in an acoustical ”shadow zone” lead to an amplification of the pressure, contrary to the free-field observations. An important result of the experiment is that the probability to observe an attenuation of the pressure level is null, for every single wave propagating in the ”shadow zone”. This result suggests that, with turbulence, the dominant propagation mechanism into the shadow-zone is scattering by sound-speed in homogeneities. In the context of sonic boom exposure on the ground, this would lead to an extension of the primary carpet of the aircraft.

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Syftet med föreliggande studie är att identifiera och beskriva de faktorer som avgör valet av implementeringsstrategi vid införande av verksamhetsstödjande system i Sverige. I litteratur-undersökningen framkom att forskning avseende kritiska framgångsfaktorer genomförts i stor utsträckning, däremot var forskningen avseende val av strategi bristfällig. Som ett resultat av detta formulerades frågeställningen för studien till vilka faktorer som påverkar valet mellan big bang och fasad strategi vid införandet av verksamhetsstödjande system inom Sverige. För att svara på studiens frågeställning genomfördes nio semi-strukturerade intervjuer med projektledare och personer med stor erfarenhet inom ämnet. Intervjuerna baserades på kritiska framgångsfaktorer, däribland ledningsstöd, realistiska måldatum och förändringsengagemang. Resultaten visar att valet av strategi till viss del varierar beroende på kontext och projektledare, dock finns det två avgörande faktorer som samtliga respondenter uppger att de måste ta ställning till. Första avgörande faktorn är huruvida systemet som ska implementeras är det första systemet inom organisationen eller om det ersätter ett gammalt system. Andra avgörande faktorn är bolagets struktur som antingen kan vara övergripande för hela organisationen, eller vara uppdelad i olika legala enheter. / The purpose of this study is to identify and describe the factors that determine the choice of implementation strategy at the introduction of operational support systems in Sweden. The literature survey revealed that research on critical success factors had been done to a large extent however; research regarding the selection of strategy was underrepresented. As a result, the research question was formulated: which factors influence the choice between the big bang and phased strategy for introducing operational support systems in companies in Sweden. To answer the research question, nine semi-structured interviews were conducted with project managers and executives in the industry. The interviews were based on critical success factors, this including management support, realistic target dates and change commitment. The results show that the choice of strategy to some extent varies by project manager; however, there are two crucial factors that all respondents stated that they must consider. The first determining factor is whether the system to be implemented is the first system in the organization or if it replaces an old system. The second crucial factor is the company's structure that can either be global for the entire organization, or be divided into different legal entities.

In this thesis, a base for the modeling and analysis of laser guided weapons is constituted. In particular, the effects of several control schemes on the performance of a generic laser guided weapon system are investigated. In this generic model, it is assumed that the velocity pursuit guidance is employed via a velocity aligning seeker as the sole sensor. The laser seeker is modeled experimentally, based on data obtained by conducting a series of tests. The laser reflection is also modeled. Aerodynamic coefficients of the generic geometry are generated by the software Missile Datcom. A nonlinear, six degree of freedom simulation is constructed incorporating 10 Hz laser sensing, velocity pursuit guidance, seeker model, and multiple control schemes. The effects of bang-bang, bang-trail-bang, multiposition and continuous control techniques on weapon performance are investigated for stationary and moving targets under ideal and noisy conditions. Flight characteristics like miss distance, range envelope, impact speed, and time of flight are monitored. Weapon&amp / #8217 / s maneuverability is investigated and the effect of employing a theoretical down sensor on the performance is demonstrated. In the light of simulation results, comparisons between various schemes are carried out, improvements on them and their flight envelopes are emphasized. It is concluded that the multiposition scheme provides a significant performance increase in most delivery types and can be an alternative to the continuous scheme. It is shown that the continuous scheme can achieve longer ranges only if backed up by a down sensor.

Orientador: Patricio Anibal Letelier Sotomayor / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-18T20:03:53Z (GMT). No. of bitstreams: 1 Manoel_JoaoPauloPitelli_D.pdf: 2670867 bytes, checksum: 990119329fe5abbf22d8a42384ff3e72 (MD5) Previous issue date: 2011 / Resumo: Espaços-tempo classicamente singulares serão estudados de um ponto de vista quântico. A utilização da mecânica quântica será feita de duas maneiras. A primeira consiste em encontrar a função de onda do Universo, resolvendo a equação de Wheeler-DeWitt para as variáveis canônicas do espaço-tempo. A segunda consiste em acoplar conformemente campos escalares e spinoriais ao campo gravitacional, estudando o comportamento de pacotes de ondas neste espaço-tempo curvo / Abstract: Classically singular spacetimes will be studied from a quantum mechanical point of view. The use of quantum mechanics will be handled in two different ways. The first consists in finding the wave function of the universe by solving the Wheeler-DeWitt equation for the canonical variables of spacetime. The second is through the conformal coupling of scalar and spinorial fields with the gravitational field, where we will study the behavior of wave packets in this curved spacetime / Doutorado / Matematica Aplicada / Doutor em Matemática Aplicada

The Standard Model of Particle Physics has been verified to unprecedented precision in the last few decades. However there are still phenomena in nature which cannot be explained, and as such new theories will be required. Since terrestrial experiments are limited in both the energy and precision that can be probed, new methods are required to search for signs of physics beyond the Standard Model. In this dissertation, I demonstrate how these theories can be probed by searching for remnants of their effects in the early Universe. In particular I focus on three possible extensions of the Standard Model: the addition of massive neutral particles as dark matter, the addition of charged massive particles, and the existence of higher dimensions. For each new model, I review the existing experimental bounds and the potential for discovering new physics in the next generation of experiments. For dark matter, I introduce six simple models which I have developed, and which involve a minimum amount of new physics, as well as reviewing one existing model of dark matter. For each model I calculate the latest constraints from astrophysics experiments, nuclear recoil experiments, and collider experiments. I also provide motivations for studying sub-GeV mass dark matter, and propose the possibility of searching for light WIMPs in the decay of B-mesons and other heavy particles. For charged massive relics, I introduce and review the recently proposed model of catalyzed Big Bang nucleosynthesis. In particular I review the production of Li6 by this mechanism, and calculate the abundance of Li7 after destruction of Be7 by charged relics. The result is that for certain natural relics CBBN is capable of removing tensions between the predicted and observed Li6 and Li7 abundances which are present in the standard model of BBN. For extra dimensions, I review the constraints on the ADD model from both astrophysics and collider experiments. I then calculate the constraints on this model from Big Bang nucleosynthesis in the early Universe. I also calculate the bounds on this model from Kaluza-Klein gravitons trapped in the galaxy which decay to electron-positron pairs, using the measured 511 keV gamma-ray flux. For each example of new physics, I find that remnants of the early Universe provide constraints on the models which are complimentary to the existing constraints from colliders and other terrestrial experiments.

Reklam har genom tiderna utvecklats från att vara övervägande argumenterande text till att påsenare år ha en mer berättande ansats, särskilt med framväxten av videoreklam. Socialamedier har lockat många företag att flytta sin reklam från traditionella medier till socialamedier på grund av den ökande användningen. Samtidigt som företag söker sig till socialamedier gör även allmänheten det, där ibland barn. Att urskilja reklam från annat innehåll pådessa plattformar har visat sig vara särskilt utmanande för barn. Mot denna bakgrund syftardenna studie till att undersöka skillnader och likheter i Kevin Bangs TikTok-videor med fokuspå deras berättarstrukturer. Studien analyserade tio videor, fem samarbetsvideor och fem av Kevin Bangs egna videor.Detta gjorde vi med hjälp av aktantmodellen, Hey You See So och plott. Studiens resultatindikerar att videorna följer liknande berättarstrukturer med några få distinkta skillnader. Detär även tydligt att hans samarbetsvideor inte går att separera från hans egna videor, främst pågrund av att det inte finns tydliga säljarargument. / Advertising has evolved over time, transitioning from predominantly persuasive text to adopting a more narrative approach in recent years, especially with the rise of video advertising. Social media has enticed many companies to shift their advertising from traditional media to social platforms due to the increasing user engagement. Simultaneously, as businesses migrate to social media, so does the public, including children. Distinguishing advertisements from other content on these platforms has proven to be particularly challenging for children. Against this backdrop, this study aims to examine differences and similarities in Kevin Bang's TikTok videos, focusing on their narrative structures.  The study analyzed ten videos, comprising five collaboration videos and five of Kevin Bang's own videos. This analysis was conducted using the actantial model, Hey You See So, and plot. The results of the study indicate that the videos follow similar narrative structures with only a few distinct differences. It is also evident that his collaboration videos cannot be easily distinguished from his own videos, primarily due to the absence of a clear selling point.

Multicellular organisms need to control their size throughout development and adult life in the face of challenges such as rapid growth. Unraveling the mechanisms that regulate tissue growth in epithelial tissues, in order to generate organs of correct size and proportion, remains a crucial goal of developmental biology. A suitable epithelial tissue for studying tissue growth in Drosophila, is the proliferative monolayer epithelial sheet of imaginal wing discs, which gives rise to the adult wing. The Hippo signaling pathway regulates tissue growth in wing development. There are several observations that link tissue growth/Hippo signaling with cell polarity and the actin cytoskeletal organization. The aim of this thesis was the study of the interplay between cell polarity, cytoskeletal organization and tissue growth. To gain further insight into how apical polarity proteins regulate tissue growth, an enhancer/suppressor screen that was previously conducted in our lab by Linda Nemetschke, was used. The screen was based on the modification of a dominant smaller wing phenotype induced upon overexpression of CrbextraTM-GFP. One of the enhancers identified in this screen is a gene called big bang (bbg). The absence of bbg results in smaller wings with a slower cell cycle and increased apoptosis in wing discs. bbg encodes a protein expressed in the apical cortex in wing disc cells and is required for the proper localization of apical proteins, like Crb, in wing disc epithelia. Bbg is also in the same complex with Spaghetti Squash (Sqh) in the apical cortex of the wing disc epithelia. sqh encodes an actin-binding protein that has actin cross-linking and contractile properties. Bbg stabilizes Sqh in the apical compartment of the cell. It is reported that both Crb and Sqh regulate tissue growth through the Hippo signaling pathway. In conclusion, Bbg regulates wing tissue growth, acting as a scaffolding molecule, through the proper localization of apical components of the cells like Crb and the cytoskeletal component Sqh.

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