Reversing with a trailer is very difficult and many drivers hesitate to even try it. This thesis examines if active steering, particularly AFS (Active Front Steering), can be used to provide assistance. For analysis and controller design a simple geometric model of car and trailer is used. The model seems to be accurate enough at the low speeds relevant for trailer reversing. It is shown that the only trailer dependent model parameter can be estimated while driving. This enables use with different trailers. Different schemes to control the system are tested. The main approach is to use the steering wheel as reference for some appropriate output signal, for example the angle between car and trailer. This makes reversing with a trailer more like reversing without a trailer. To turn left, the driver simply turns the steering wheel left and drives. Test driving, as well as theoretical analysis, shows that the resulting system is stable. Of the eight drivers that have tested this type of control, five found it to be a great advantage while two considered it more confusing than helpful. A major problem with this control approach has to do with the way AFS is constructed. With AFS, the torque required to turn the front wheels results in a reaction torque in the steering wheel. Together with the reference tracking controllers, this makes the steering wheel unstable. Theoretical analysis implies that this problem has to be solved mechanically. One solution would be to combine AFS with electric power steering. This thesis also presents a trajectory tracking scheme to autonomously reverse with a trailer. Starting from the current trailer position and the desired trajectory an appropriate turning radius for the trailer is decided. Within certain limits, this will stabilize the car as well. The desired trajectory can be programmed beforehand, but it can also be saved while driving forward. Both variants have been tested with good results.

This thesis has aimed to study steering process and institutionalization in the context of educational policy work. This has been conducted by using empirical material from the political decision-making process that preceded the implementation of a new national program on how principals should be educated and certified. By using an aggregated theoretical point of view containing new institutionalism and traditional Swedish curriculum theory, the process was analyzed from different perspectives. The results depict a process that contained several actors who tried to shape the principal education program differently. From the theoretical perspectives, the decision-making process could be understood as an act of both self-interest as well as trust in their own beliefs and cultural values. The result also tells us how an institutional environment is created and what that implies for actors who are parts of that environment.

Denna uppsats syftar till att undersöka elevers syn på undervisning och lärande. Undersökningen visar vad elever tycker är bra lektioner och när de tycker att de lär sig bäst, samt undersökt detta i relation till skolans styrdokument. Anledningen till detta är att skolans läroplan tillsammans med Skolverkets Allmänna råd ger lärare råd om hur de bör planera och genomföra undervisning för att nå bästa resultat med våra elever. Undersökningen är kvantitativ i form av en enkätundersökning som genomförts som totalundersökning på en gymnasieskola i en mindre kommun i Sverige. Enkäten består av påståenden om undervisning och lärande och är konstruerad utifrån en begreppsdefinition som bygger på svensk skolas styrdokument och aktuell forskning. Resultaten visar att elever lyfter fram tydlighet och relationer som viktigast för god undervisning och effektivt lärande. Undervisningsmetoder framstår som minst viktiga. Resultaten tyder också på att eleverna i stort upplever samma faktorer som avgörande för undervisning och lärande som våra styrdokument förespråkar. / This paper aims to investigate pupil’s views on teaching and learning. I look at what pupils think are good lessons and place this in context with the Swedish school systems steering documents, such as curriculum and general advice from the education authorities; Skolverket. The method of this paper is a quantitative survey including the entire population of pupils at one Swedish upper secondary school in a smaller municipality. The survey consists of statements about teaching and learning constructed from a definition of good teaching based on the Swedish school systems steering documents and current research. The results show that pupils value understanding and relationships as most important for good teaching and effective learning. Methods of teaching are considered as the least important. The results also show that the pupils in large value the same factors as do our steering documents.

This thesis focuses on a type of antenna known as the reflectarray antenna. In particular, it looks at the design of an active reconfigurable reflectarray antenna, which has not received much attention in the reflectarray community. Potential applications include deployment as a high gain, reconfigurable antenna for communication links, and as a spatial power combiner. The reflectarray element is an aperture-coupled patch that accepts a linearly polarized wave, phase shifts and amplifies the guided-waves in the transmission lines, and then re-radiates an orthogonally polarized wave. Stability analysis of the element, experimental results of the designed phase shifter and simulation and experimental results of the element are presented. Fabrication details of a 48 element reflectarray and challenges faced during experimental characterization of the elements are also discussed. The two dimensional beamforming capability and amplifying nature of the array are successfully demonstrated and veri fied, indicating robustness to phase errors and oscillating elements.

This thesis focuses on a type of antenna known as the reflectarray antenna. In particular, it looks at the design of an active reconfigurable reflectarray antenna, which has not received much attention in the reflectarray community. Potential applications include deployment as a high gain, reconfigurable antenna for communication links, and as a spatial power combiner. The reflectarray element is an aperture-coupled patch that accepts a linearly polarized wave, phase shifts and amplifies the guided-waves in the transmission lines, and then re-radiates an orthogonally polarized wave. Stability analysis of the element, experimental results of the designed phase shifter and simulation and experimental results of the element are presented. Fabrication details of a 48 element reflectarray and challenges faced during experimental characterization of the elements are also discussed. The two dimensional beamforming capability and amplifying nature of the array are successfully demonstrated and veri fied, indicating robustness to phase errors and oscillating elements.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Includes bibliographic references.

Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.

Todos os anos, milhões de reais são gastos para cobrir os custos de garantia de caixas de direção que apresentam problemas de ruído e inconvenientes são causados nas linhas de montagem das grandes montadoras devido a este mesmo problema. Parte destas ocorrências se devem a um ruído específico chamado de Rattle Noise originado por uma operação de regulagem incorreta do bujão de ajuste. Em caixas de direção cujo “design” não permite uma medição direta da regulagem do sistema de ajuste, não existe um meio de avaliar a qualidade da operação e garantir que todas as peças estejam dentro das especificações. Baseado neste problema, este trabalho visa propor uma metodologia de avaliação da qualidade da operação de ajuste da caixa de direção de uma maneira indireta, porém com uma representação muito próxima do resultado que seria apresentado por uma medição direta, se o “design” do produto permitisse. Para tornar isso possível, foram realizados ensaios com caixas de direção em uma bancada experimental de testes aplicando-se a cremalheira cargas perpendiculares a seu eixo e momentos torsores. Foram avaliadas as respostas da amplitude do movimento angular descrito e também do deslocamento da cremalheira no sentido do seu raio observando-se a correlação que as respostas tinham com a real folga do mancal no interior do sistema de ajuste. Estes ensaios mostram que existe uma correlação muito forte entre as variáveis medidas externamente e a real flutuação do mancal no interior do sistema de ajuste e, através da regressão linear, uma equação foi definida para expressar este correlacionamento. Uma máquina foi construída para que a verificação fosse feita em 100% dos mecanismos produzidos na linha de montagem de um modelo de caixa de direção. Depois de construída a máquina, validou-se o seu funcionamento através dos estudos de R&R (Repetitividade e Reprodutibilidade), que ficaram abaixo de 20%, e da calibração da mesma comparando-se os resultados fornecidos pela máquina com as leituras realizadas de forma direta através de peças com o “design” alterado de forma a tornar isto possível, mostrando uma correlação de 99%. Hoje, o sistema está rodando perfeitamente em uma linha de montagem de um grande fabricante de sistemas de direção nacional. / Every year, millions of dollars are spent to cover the insurance costs of steering systems that have noise problems and inconveniences are caused in assembly lines of major car industry because of this same problem. Most of these occurrences are due to a specific noise called Rattle Noise caused by an incorrect operation of the adjustment screw to adjust the steering box. In cases where the direction of "design" does not allow a direct measurement of the values of the adjustment system, there is no way to assess the quality of operation and thus ensure that all parts are within specifications. Based on this problem, this work proposes a methodology to assess the quality of the adjust operation of the steering system in an indirect way, but with a very close representation of the results to be presented by a direct measurement if the "product design" had allowed. To make this possible, tests on steering systems were conducted in a test bench each exciting to rack with loads perpendicular to its axis and torsion loads. We studied responses of the magnitude of angular momentum described by the system and also the displacement of the rack along its radius by observing the correlation within the measured values to the actual bearing clearance into the system. These tests showed that there was a very strong correlation between the measured variables and externally real bearing fluctuation within the system of adjustment and using a linear regression, an equation was defined to express this correlation. A machine was built in order to verify 100% of the products in the assembly line of a vehicle steering system. Once built the machine and validated its operation through R & R studies, which has shown results below of 20%, the system was calibrated comparing the output of the machine with the readings taken directly in parts with the altered "design" to make this possible, showing a correlation of 99%. Today, the system is running perfectly on an assembly line of a major national manufacturer of steering systems.

Magister Educationis - MEd / The debate around the roles of universities is not new. One of the debated issues relates to who defines the role and priorities of universities. A number of authors (Ashby, 1964; Yesufu, 1973; Court, 1980; Sherman, 1990; Saint, 1992; Ajayi, Goma & Johnson, 1996; Lulat, 2003; Van Wyk & Higgs, 2007) have taken into account the colonial legacy when approaching the topic of higher education establishment in post-colonial Africa. What may seem clear is that universities have roles to play. Those roles are often stated in higher education legislation, policy and plans, by universities themselves or even by their stakeholders. Although studies on higher education in Mozambique (Chilundo et al., 2000; Mário et al., 2003; Brito, 2003; Langa, 2006; Beverwijk, Goedegebuure & Huisman, 2008; Cloete et al., 2011) have attempted to address post-colonial higher education in Mozambique, none addresses, in depth, the purpose of establishment or the debates around the role of universities. That is the gap this study has identified and intends to address by investigating the way in which the roles of the Eduardo Mondlane University (UEM) were defined. Taking into account the relationship between state, university, society and market, the roles of the university are understood as both what universities are expected to do and what the university perceives it should do. The university’s roles are located at both macro-level and institutional level. At the macro-level, university’s roles are clearly outlined by state legislation and policy on higher education (Cloete & Maassen, 2006: 10-12). At the institutional level, however, the university’s roles are defined by the university itself and relevant stakeholders (Clark, 1983: 140-145). Apart from having located university’s roles at these two levels, a conceptual analytical framework was drawn from the work of Clark (1983) and Cloete and Maassen (2006) to analyse role formation using three model types: state control, market steering and academic oligarchy. The data collection, consisting of document collection and interviews, was undertaken from December 2010 to May 2011. Documents, archival records, universities’ policies and government policies on higher education in Mozambique were collected. Semi-structured interviews were conducted with UEM and Ministry of Education staff.

abstract: Presented in this thesis are two projects that fall under the umbrella of magnetically actuated electronics and robotics for medical applications. First, magnetically actuated tunable soft electronics are discussed in Chapter 2. Wearable and implantable soft electronics are clinically available and commonplace. However, these devices can be taken a step further to improve the lives of their users by adding remote tunability. The four electric units tested were planar inductors, axial inductors, capacitors and resistors. The devices were made of polydimethylsiloxane (PDMS) for flexibility with copper components for conductivity. The units were tuned using magnets and mobile components comprised of iron filings and ferrofluid. The characteristic properties examined for each unit are as follows: inductance and quality factor (Q-factor) for inductors, capacitance and Q-factor for capacitors, and impedance for resistors. There were two groups of tuning tests: quantity effect and position effect of the mobile component. The position of the mobile component had a larger effect on each unit, with 20-23% change in inductance for inductors (from 3.31 µH for planar and 0.44 µH for axial), 12.7% from 2.854 pF for capacitors and 185.3% from 0.353 kΩ for resistors. Chapter 3 discusses a magnetic needle tracking device with operative assistance from a six degree-of-freedom robotic arm. Traditional needle steering faces many obstacles such as torsional effects, buckling, and small radii of curvature. To improve upon the concept, this project uses permanent magnets in parallel with a tracking system to steer and determine the position and orientation of the needle in real time. The magnet configuration is located at the end effector of the robotic arm. The trajectory of the end effector depends on the needle’s path, and vice versa. The distance the needle travels inside the workspace is tracked by a direct current (DC) motor, to which the needle is tethered. Combining this length with the pose of the end effector, the position and orientation of the needle can be calculated. Simulation of this tracking device has shown the functionality of the system. Testing has been done to confirm that a single magnet pulls the needle through the phantom tissue. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2020