Coating onto a moving substrate several films simultaneously on top of each other is a challenging exercise. This is due to the fact, depending on operating conditions (thickness and velocity of individual layers and the physical properties of the coating fluids), flow instabilities may arise at the interfaces between the layers and on the top layer. These instabilities ruin the application of the final multi-layered coating and must be avoided. This research addresses this coating flow situation and seeks to develop guidelines to avoid these instabilities. Following a critical literature survey, this thesis presents a novel experimental method that visualises multi-layered coating flow down an inclined multi-slot die. The visualisation is obtained using a unique configuration including a high-speed camera, telecentric objective lens and illumination. The results show for a single layer, as the die angle and Reynolds number increases, the flow becomes more unstable and for a dual layer flow, as Re increases the peak to peak amplitude and the frequency decreases at the free surface and interface. The latter was unexpected and does not conform with existing literature. The triple layer results show either a monotonically increasing or increasing from first to second layer viscosity stratifications are the most stable flows along with flow heights in the first and second layers of <22% and >18% of the total thickness respectively, which concur with current literature. The visualisation additionally obtained other instabilities including single layer back-wetting and vortices, and multilayer slot invasion with the findings concurring with current literature. / EPRSC/Tata Steel Industrial CASE Studentship; EP/J501840/1

This dissertation aims to contribute toward the understanding of water-entry and -exit behaviors in nature. Since water is nearly a thousand times denser than air, transitioning between the two mediums is often associated with significant changes in force. Three topics with implications in water-entry are discussed, along with a fourth topic on water-exit. For a plunge-diving seabird, the first two stages of water-entry (initial impact and air-cavity formation) create large stresses on the bird's neck. Linear stability analysis of a cone-beam system impacting water shows buckling and non-buckling behaviors on the beam, which is extended to the diving birds. The next topic is related to the third stage of water-entry (air-cavity pinch-off), in which the chest feathers come in contact with the water. Here, the elasticity of Northern Gannet contour feathers is calculated using the nonlinear bending equation. The third topic will explore the formation of ripples along air cavity walls and their resulting force after pinch-off. An acoustic model predicts the observed wavelengths of the ripples. The final topic will delve into the mechanics of how animals leap out of water. A scaling law that balances the power of thrust and drag will predict the height of the jump. Finally, a bio-inspired robot was built to help identify physical conditions required to jump out of water. / Ph. D. / In nature, animals use enter and exit water (water-entry and water-exit, respectively) as a strategy for hunting prey and/or escaping predators. In this dissertation, we focus on the fluid mechanics of water-entry and water-exit phenomena as it pertains to animals. First, we study how seabirds plunge-dive into water at high speeds without neck injuries. Second, we discuss calculating the elasticity of bird feathers. Next, the rippling behavior of air-cavities is studied in the context of force production. Finally, we study the water-exit phenomenon of animals leaping out of water. The topics of this dissertation have implications in the water-entry and -exit of vehicles and autonomous robotics.

We study fast-slow versions of the SIR, SIRS and SIRWS epidemiological models, and of the SIRS epidemiological model on homogeneous graphs, obtained through the application of the moment closure method. The multiple time scale behavior is introduced to account for large differences between some of the rates of the epidemiological pathways. Our main purpose is to show that the fast-slow models, even though in nonstandard form, can be studied by means of Geometric Singular Perturbation Theory (GSPT). In particular, without using Lyapunov's method, we are able to not only analyze the stability of the endemic equilibria of the SIR and SIRS models, but also to show that in the remaining models limit cycles arise. We show that the proposed approach is particularly useful in more complicated (higher dimensional) models such as the SIRWS model and the SIRS on homogeneous graphs, for which we provide a detailed description of their dynamics by combining analytic and numerical techniques. In particular, for the latter we show that the model can give rise to periodic solutions, differently from the corresponding model based on homogeneous mixing.

Pour les contribuables détenteurs de titres en forte plus-value latente qui souhaitent, d’une part, utiliser leur valorisation pour réaliser de nouveaux investissements et, d’autre part, limiter l’impôt afférent à cette plus-value, une opération a été imaginée : l’apport-cession-délocalisation. Il s’agit pour le contribuable d’apporter ses titres à une société sous un régime de différé d’imposition – report ou sursis – avant que cette dernière ne les cède en franchise d’impôt. Ce faisant, la société bénéficiaire de l’apport peut réinvestir le prix de cession et le contribuable n’est imposé que lors de la cession ultérieure des titres reçus en échange de l’apport. Réalisé dans un cadre national, l’apport-cession n’octroie au contribuable qu’un délai dans l’établissement de l’impôt de plus-value mais combiné à une délocalisation du domicile fiscal, cette opération peut aboutir à sa diminution voire à sa suppression. Toutefois, la jurisprudence et le législateur sont intervenus afin d’encadrer cette opération en posant les conditions dans lesquelles elle serait abusive puis en instaurant un nouveau régime spécifique aux apports réalisés en faveur d’une société contrôlée par l’apporteur et en remettant en place un système d’exit tax. Certes, ces nouveaux encadrements impliquent l’adaptation des modalités de réalisation de l’opération et en limitent les effets, particulièrement l’exit tax, toutefois, l’opération demeure possible et avantageuse. En outre, certains aspects de l’exit tax peuvent être contestés au regard du droit de l’Union européenne et conventionnel de sorte que sa pérennité – et donc les limites qu’il implique dans le cadre de cette opération – est incertaine. / A dedicated three-step tax scheme has been designed for individuals holding assets with a latent capital gain; willing to reinvest their profits into other activities and reduce taxes on capital gains normally owed: Capital contribution of the assets held by this individual to a company in exchange of shares (Step 1), sales of those assets by the this company to a third-party (Step 2), relocation of the individual to another country (Step 3). The objective is for this individual to beneficiate from a deferred taxation on the capital contribution and for this company to sell assets on a tax-free basis. The company will therefore be able to reinvest the price from the assets sales and the individual will only be taxed when received shares are subsequently sold. In domestic situations, this tax scheme only offers deferral of taxes on capital gains ; but combined with the individual relocation, it enables to drastically reduce if not totally suppress taxes. Since then, legislators and judges have clearly identified conditions defining tax abuse, have defined new rules related to capital contribution to companies controlled by the contributor and have implemented exit-tax mechanisms. Despite this new legal framework, the studied tax scheme is still of significant interest. Additionally, some aspects of the exit-tax might certainly be challenged in regards to European Union law and European fiscal conventions.

Cette thèse examine la dynamique des relations professionnelles dans les entreprises publiques en Chine, à partir de deux monographies réalisées dans des établissements situés à Shanghai. Elle s’interroge notamment aux conséquences des transformations du secteur public dans le prolongement des réformes engagées dans les années 1980. Ces réformes conduisent à distinguer véritablement les intérêts des salariés de ceux des directions d’entreprise. En ce sens, elles ouvrent la voie à l’émergence d’un système de relations professionnelles. Elle s’attache à l’analyse des politiques du personnel dans ces entreprises, marquées par une autonomisation croissante à l’égard des autorités publiques, à la transformation du rôle du syndicat dans ce contexte et à l’action collective des salariés notamment dans le contexte de restructurations et d’incertitude sur l’avenir de l’entreprise. / This thesis examines the dynamics of employments relations in state-owned enterprises in China based on monographs produced in the Shanghai branches of two companies. In particular, it is intended to discuss the impact of transformations in the public sector from reforms in the 1980s. These reforms led to truly distinguish the interests of labor from those of management. In this sense, they paved the way for the emergence of a system of employments relations. This thesis focuses on the analysis of human resource policies in these companies, which were marked by increasing independence from the public authorities, the changing role of the union in this context, and the collective action of workers in the context of restructuring and uncertainty about the future of the company.

Abstract This thesis concentrates on joint optimization of transmit power allocation and receive filtering in multiuser, multi-antenna communications. Due to the increasing number of wireless devices, the design of energy-efficient communication links is becoming increasingly important. In cellular mobile communications, reducing the average power consumption in uplink transmission is beneficial for users in order to extend battery life and, hence, energy efficiency in general. However, the power consumption of the high power amplifier (HPA) at the transmitter depends on the peak power of the transmission. This thesis focuses on power allocation problems for single-carrier (SC) frequency division multiple access (FDMA) and orthogonal FDMA (OFDMA) transmission assuming iterative reception. The goal in the first scheme presented in this thesis is to reduce the average power consumption by designing a power allocation method that takes into account the convergence properties of an iterative receiver in multiuser uplink communications. The proposed scheme can guarantee that the desired quality of service (QoS) is achieved after a sufficient number of iterations. Reducing the peak-to-average power ratio (PAPR) in any transmission system is beneficial because it allows the use of inexpensive, energy-efficient power amplifiers. The goal in the second scheme presented in this thesis is to control the PAPR of the transmitted signal. Hence, in addition to the QoS constraint, the instantaneous PAPR constraint is derived for SC-FDMA and OFDMA transmission. Moreover, a statistical approach is considered in which the power variance of the transmitted waveform is controlled. The QoS and PAPR constraints are considered jointly and, therefore, the proposed power allocation strategy jointly takes into account the channel quality and the PAPR characteristics of the power amplifier. However, the PAPR constraint can be adopted to any SC-FDMA or OFDMA framework and it is not restricted to the scheme presented in this thesis. The objective of the optimization problems considered throughout the thesis is to minimize the sum power. The majority of the derived constraints are non-convex and therefore, two alternative successive convex approximations (SCAs) are derived for all the non-convex constraints considered. The numerical results show that the proposed power allocation strategies can significantly reduce the average transmission power of users while allowing flexible PAPR control. Hence, the proposed methods can be used to extend battery life for users and especially improve the QoS at the cell edges. / Tiivistelmä Väitöskirjassa tutkitaan lähettimessä tapahtuvan tehoallokoinnin sekä vastaanottimessa tapahtuvan signaalin suodatuksen yhteisoptimointia monikäyttöön suunnatussa langattomassa moniantennikommunikaatiossa. Langattomien laitteiden lukumäärän kasvaessa energiatehokkuuden merkitys tiedonsiirtolinkkien suunnittelussa korostuu. Soluihin perustuvassa langattomassa tietoliikenteessä keskimääräisen tehonkulutuksen pienentäminen ylälinkkilähetyksessä (käyttäjältä tukiasemaan) on tärkeää käyttäjän kannalta, sillä se pidentää laitteen akun kestoa. Lähettimen tehovahvistimen (high power amplifier (HPA)) tehonkulutus on kuitenkin verrannollinen lähetyksen huipputehoon. Väitöskirjassa luodaaan uusia menetelmiä sekä vertaillaan tehoallokointia yhden kantoaallon taajuustason monikäyttöön (single carrier frequency division multiple access (SC-FDMA)) ja ortogonaalisen taajuustason monikäyttöön (orthogonal FDMA (OFDMA)) perustuvissa lähetysteknologioissa. Työn ensimmäisessä osiossa tavoitteena on keskimääräisen tehonkulutuksen pienentäminen monen käyttäjän ylälinkkikommunikaatiossa suunnittelemalla tehoallokointimenetelmä, joka ottaa huomioon iteratiivisen vastaanottimen konvergenssiominaisuudet. Työssä ehdotettu menetelmä takaa vastaanotetun informaation halutun laadun (quality of service (QoS)) riittävän monen vastaanottimessa tehdyn iteraation jälkeen. Huipputehon ja keskitehon suhteen (peak to average power ratio (PAPR)) pienentäminen missä tahansa lähetyksessä on hyödyllistä, sillä sen ansiosta voidaan käyttää energiatehokkaampia ja halvempia tehovahvistimia. Työn jälkimmäisessä osiossa tavoitteena on kontrolloida lähetetyn signaalin huipputehon ja keskitehon suhdetta. Työn ensimmäisessä osiossa esitetyn QoS-rajoitteen lisäksi tehoallokointia rajoitetaan symbolisekvenssikohtaisella PAPR-rajoitteella SCFDMA- ja OFDMA-lähetyksessä. Lisäksi esitetään tilastollinen menetelmä, jossa rajoitetaan lähetetyn signaalin tehon varianssia. Kun käytetään yhtäaikaisesti QoS- ja PAPR-rajoitteita, voidaan tiedonsiirtokanavaan suunnitella optimaalinen tehoallokointi ottaen huomioon tehovahvistimen epälineaarisuudet. Työssä esitetty PAPR-rajoite on kuitenkin geneerinen, ja se voidaan sovittaa mihin tahansa SCFDMA- tai OFDMA- optimointikehykseen. Työssä esitettävien optimointiongelmien tavoitteena on käyttäjien summatehon minimointi. Suurin osa työssä esiintyvistä ongelmista on ei-konvekseja, joten siinä esitetään kaksi vaihtoehtoista peräkkäinen konveksi approksimaatio (successive convex approximation (SCA)) -menetelmää kaikille ei-konvekseille rajoitteille. Numeeriset tulokset osoittavat, että esitetyt tehoallokointimenetelmät pienentävät merkittävästi keskimääräistä tehonkulutusta mahdollistaen lisäksi adaptiivisen PAPR-kontrolloinnin. Väitöskirjassa esitettyjen menetelmien avulla voidaan pidentää mobiilikäyttäjien akun kestoa sekä erityisesti parantaa solun reunakäyttäjien palvelun laatua.

Les standards « Long-term evolution » (LTE) et LTE-Advanced (LTE-A) devraient influencer fortement l’avenir de la cinquième génération (5G) des réseaux mobiles. Ces normes exigent de hauts débits de données et une qualité de service de très bon niveau, ce qui permet d’assurer un faible taux d’erreur, avec une faible latence. Par ailleurs, la complexité doit être limitée. Dans le but de déterminer des solutions technologiques modernes qui satisfont ces contraintes fortes, nous étudions dans la thèse des systèmes de communication sans fil MIMO codés. D’abord, nous imposons un simple code convolutif récursif systématique (RSC) pour limiter la complexité et la latence. En considérant des récepteurs itératifs, nous optimisons alors la performance en termes de taux d’erreur de ces systèmes en définissant un précodage linéaire MIMO et des techniques de mapping appropriées. Dans la deuxième partie de la thèse, nous remplaçons le RSC par un LDPC non-binaire (NB-LDPC). Nous proposons d’utiliser les techniques de précodage MIMO afin de réduire la complexité des récepteurs des systèmes MIMO intégrant des codes NB-LDPC. Enfin, nous proposons également un nouvel algorithme de décodage itératif à faible complexité adapté aux codes NB-LDPC. / The long-term evolution (LTE) and the LTE-Advanced (LTE-A) standardizations are predicted to play essential roles in the future fifth-generation (5G) mobile networks. These standardizations require high data rate and high quality of service, which assures low error-rate and low latency. Besides, as discussed in the recent surveys, low complexity communication systems are also essential in the next 5G mobile networks. To adapt to the modern trend of technology, in this PhD thesis, we investigate the multiple-input multiple-output (MIMO) wireless communication schemes. In the first part of this thesis, low-complex forward error correction (FEC) codes are used for low complexity and latency. By considering iterative receivers at the receiver side, we exploit MIMO linear precoding and mapping methods to optimize the error-rate performance of these systems. In the second part of this thesis, non-binary low density parity check (NB-LDPC) codes are investigated. We propose to use MIMO precoders to reduce the complexity for NB-LDPC encoded MIMO systems. A novel low complexity decoding algorithm for NB-LDPC codes is also proposed at the end of this thesis.

Bakgrund: Riskkapital är en betydande finansieringsmetod för unga företag. Riskkapital tillhandahålls av Venture Capital-bolag som har en betydande inverkan på det investerade företaget. Venture Capital-bolagens fokus under den period som de är investerade i portföljbolagen ligger på tillförsel av värde och övervakning. Trycket för företag att arbeta mer med hållbarhetsfrågor har ökat. Vilket öppnar frågan om hur de kan använda ESG för att öka värdet i sina portföljbolag. Mål: Syftet med denna studie är att ge förståelse för hur svenska Venture Capital-bolag arbetar med ESG som ett verktyg längs alla investeringsfaser för att kunna tillföra värde till sina portföljbolag. Metod: För att besvara frågeställningen samt uppnå syftet av studien har semistrukturerade intervjuer genomförts. Det har genomförts sex intervjuer där fem av respondenterna arbetade på ett Venture Capital-bolag och en respondent arbetade på en intresseorganisation. Resultaten av intervjuerna jämfördes med tidigare separerade resultat till ämnena ESG och Venture Capital. Slutsats: Betydelsen av ESG i portföljföretag kan variera på grund av bristande standard inom branschen. Några monetära värdeökningar har inte kunnat fastställas däremot är en del av respondenterna eniga om att ESG bidrar till värdeökning genom mjukavärden. Alla respondenter tror att ESG kommer ha en betydande roll i framtiden för branschen. Vidare har det kunnat observeras att respondenter tror på att ESG bidrar till riskminimering som enligt teorin tillför värde i bolag. / Background: Venture Capital is a significant financing method for young companies. Venture capital is provided by Venture Capital companies that have a significant impact on the invested company. The focus of the Venture Capital companies during the period in which they are invested in the portfolio companies is on the supply of value and supervision. The pressure for companies to work more with sustainability issues has increased. Which opens the question of how they can use ESG to increase the value of their portfolio companies.  Objective: The aim of this study is to provide understanding how Swedish Venture Capital are working with ESG as a toll along all investment phases to be able to add value to their portfolio companies.  Methodology: To answer the question and achieve the purpose of the study, semistructured interviews were conducted. Six interviews were conducted in which five of the respondents worked at a Venture Capital company and one respondent worked at an interest group. The results of the interviews were compared with previously separated results for the topics ESG and Venture Capital.  Conclusion: The importance of ESG in portfolio companies may vary due to lack of industry standards. No monetary value increases could be determined, however, some of the respondents agree that ESG contributes to value increases through soft values. All respondents believe that ESG will play a significant role in the future of the industry. Furthermore, it has been observed that respondents believe that ESG contributes to risk minimization, which according to the theory adds value in companies.

School Choice is a topic that finds itself at the top of school reform and political agendas across the United States, while also being a significant focal point in the educational literature. However, little attention in the debate has been placed on private, independent school choice – including private religious school choice – despite that data that shows “seventy-nine percent of all private schools had a religious affiliation in 1999– 2000: 30 percent . . . affiliated with the Roman Catholic Church, and 49 percent with other religious groups” (U.S. Department of Education, 2002, p. 3) and that “initial research on school choice that concentrated on private schools did acknowledge that many parents are likely to choose a private school for religious values” (Bauch and Goldring, 1995). This study focuses on examining the choice behaviors of families who choose independent, nondenominational Christian education, including the reasons they choose to exit before graduation and including the central role of information sources in making such choices. The study uses Rational Choice Theory and Hirschman’s Exit, Voice and Loyalty Theory as theoretical frameworks in order to couch the findings. The conclusions of this study are further couched in a bi-modal framework that posits choice involves “foundational factors” necessary for further investigation of potential schools and “factors of ethos” that, in essence, “break the tie” in the choice process – leading families to choose one particular school over others. The findings of the study, similar to the findings within other school choice literature, show that word-of-mouth information sources – predominant in informal/relational connections – are clearly the “most helpful” and “most important” sources of information in the choice process. However, the importance of web-based sources and achievement test scores also are found to be significant information sources for families who choose private, nondenominational Christian Education. In addition, in this study the differences between exiters and families that reenroll are not shown to be statistically significant and, therefore, the author suggests that theories focused on the ongoing relationships between constituents and organizations, instead of theories related to exit such as Hirschman’s Exit theory, may be more beneficial in the ongoing school choice and school reform debates.

This study examines the messages and accuracy of the messages sent to students from the Arizona Instrument to Measure Standards (AIMS) math test regarding academic preparedness for postsecondary education. Previous studies investigating messages sent to students, derived from information such as educational standards, grades, course taking policies, test material, and college admissions requirements, focused on content alignment of secondary and postsecondary content standards. However, a dearth of research exists on messages from high school performance, as measured by exit exams and college performance measured by grades, major selection, or graduation. This study addresses the need to understand and interpret messages students receive based on academic performance. Specifically, this study aims to answer three questions. First, what is the relationship between AIMS math scores and college math performance defined by the University of Arizona math requirement and college graduation? Second, to what degree do AIMS math scores predict college math performance? Third, what is the average AIMS math score and performance level for students who choose certain majors? To answer the research questions posed in this study, various statistical analyses were employed. To answer the first question, a one-way ANOVA and logistic regression analyses were used. A linear regression analysis served to analyze the second and third questions. Results indicate that the messages sent to students regarding college readiness are, in fact, well aligned and clear and consistent. Also, there is evidence that the messages vary by gender and ethnicity.