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Detta arbete är ett examensarbete inom maskinteknik som utförts i samarbete med Westermo. Westermo är ett växande företag som tillverkar produkter inom industriell datakommunikation. För att behålla sin marknadsposition och konkurrenskraft arbetar de med ständiga förbättringar och utveckling av sin produktion och dess effektivitet. Vårt uppdrag på Westermo var att se över effektiviteten i slutmonteringen då montörerna inte hinner med att producera i den takt som krävs på grund av den höga efterfrågan. Att montörerna inte hinner med tror företaget beror på att montörerna själva måste förbereda sitt material till varje tillverkningsorder. I den här rapporten kommer ni att hitta förbättringsförslag på hur Westermo kan jämna ut flödet och effektivisera materialhanteringen i slutmonteringen. För att göra detta kommer framför allt teorier och verktyg inom Lean att användas.  De förbättringsförslag som arbetet tagit fram är uppdelat i två kategorier. Den första handlar om att en ny arbetsroll ska införas som ska ansvara för materialhanteringen. Den andra handlar om en implementering av ett två-binge system vid monteringsstationen. Båda lösningsförslagen bidrar till en flödesutjämning och minskar stopp i produktionen. / This work is a degree project in mechanical engineering carried out in collaboration with Westermo. Westermo is a growing company that manufactures products in industrial data communication. In order to maintain their market position and competitiveness, they work with continuous improvements and development of their production and its efficiency. Due to the increased demand the operators do not have time to manufacture all products on time. The company believes this is due to the fact that the operators themselves must prepare all material for each order. This work is about developing improvement solutions that even out the flow and streamline the material management. To be able to do this, tools within Lean will be used.    The improvement solutions that the work has developed are divided into two categories. The first is about an introduction of a new work role that will be responsible for all material management. The second one is about an implementation of a “två-binge” system. Both solutions contribute to a flow equalization and reduce stop in the production.

Diffusion Tensor Magnetic Resonance Imaging (DT-MRI), also known as Diffusion Tensor Imaging (DTI), is a unique medical imaging modality that provides non-invasive estimates of White Matter (WM) connectivity based on local principal directions of anisotropic water diffusion. DTI tractography estimates are a macroscopically sampled description of underlying microscopic structure, and are therefore of limited validity. The under-sampling of underlying white matter structure in DTI data gives rise to Intra-Voxel Orientational Heterogeneity (IVOH), a condition in which white matter structures of multiple different orientations are averaged into a single DTI voxel sample, causing a loss of validity in the diffusion tensor model. Fast Marching Tractography (FMT) algorithms based on fast marching level set methods have been proposed to better handle the presence of IVOH in DTI data when compared to older Streamline Tractography (SLT) methods. However, the actual performance advantage of any tractography algorithm over another cannot be conclusively stated until a ground truth standard of comparison is developed. This work develops an optimized version of the FMT algorithm that is dubbed the Front Propagation Tractography (FPT) algorithm. The FPT algorithm includes unique approaches to the speed function, connectivity estimation, and likelihood estimation components of the FMT framework. The performance of the FPT algorithm is compared against the SLT algorithm using ground truth software phantom data and human brain data. Software phantom ground truth experiments compare the performance of each algorithm in single tract and crossing tract structures for varying levels of diffusion tensor field perturbation. Human brain estimates in the corpus callosum yield qualitative comparisons from inspection of 3D visualizations. A final area of exploration is the construction and analysis of a ground truth physical DTI phantom manifesting IVOH. / Master of Science

The linear instability of laterally diverging/converging flows is an important aspect towards understanding the laminar-transition process in many viscous flows. In this work the linear instability of constant pressure laterally diverging/converging flow has been investigated. The laminar velocity field for laterally diverging/converging flows, under the source/sink approximation, has been reduced to two-dimensional flows. This reduction is alternative to the Mangier transformation used earlier. For a constant pressure laterally strained flow, the laminar velocity is found to be governed by the Blasius equation for flow over a flat plate. The non-parallel linear instability of constant pressure laterally strained flows has been examined. The instability equation is found to be same as that for the Blasius flow. This implies that the stability is same as that for the Blasius flow. A lateral divergence/convergence is shown to alter the Reynolds number from that in a two-dimensional flow. The instability of a laterally converging/diverging flow thus can be obtained from the available results for the Blasius flow by scaling the Reynolds numbers. This leads to the result that while a diverging flow is more unstable than the Blasius flow, a converging flow is more stable. Some additional relevant results are also presented.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os escoamentos altamente convectivos representam um desafio na simulação pelo método de elementos finitos. Com a solução de elementos finitos de Galerkin para escoamentos incompressíveis, a matriz associada ao termo convectivo é não simétrica, e portanto, a propiedade de aproximação ótima é perdida. Na prática as soluções apresentam oscilações espúrias. Muitos métodos foram desenvolvidos com o fim de resolver esse problema. Neste trabalho apresentamos um método semi- Lagrangeano, o qual é implicitamente um método do tipo upwind, que portanto resolve o problema anterior, e comparamos o desempenho do método na solução das equações de convecção-difusão e Navier-Stokes incompressível com o Streamline Upwind Petrov Galerkin (SUPG), um método estabilizador de reconhecido desempenho. No SUPG, as funções de forma e de teste são tomadas em espaços diferentes, criando um efeito tal que as oscilações espúrias são drasticamente atenuadas. O método semi-Lagrangeano é um método de fator de integração, no qual o fator é um operador de convecção que se desloca para um sistema de coordenadas móveis no fluido, mas restabelece o sistema de coordenadas Lagrangeanas depois de cada passo de tempo. Isto prevê estabilidade e a possibilidade de utilizar passos de tempo maiores.Existem muitos trabalhos na literatura analisando métodos estabilizadores, mas não assim com o método semi-Lagrangeano, o que representa a contribuição principal deste trabalho: reconhecer as virtudes e as fraquezas do método semi-Lagrangeano em escoamentos dominados pelo fenômeno de convecção. / Convection dominated flows represent a challenge for finite element method simulation. Many methods have been developed to address this problem. In this work we compare the performance of two methods in the solution of the convectiondiffusion and Navier-Stokes equations on environmental flow problems: the Streamline Upwind Petrov Galerkin (SUPG) and the semi-Lagrangian method. In Galerkin finite element methods for fluid flows, the matrix associated with the convective term is non-symmetric, and as a result, the best approximation property is lost. In practice, solutions are often corrupted by espurious oscillations. In this work, we present a semi- Lagrangian method, which is implicitly an upwind method, therefore solving the spurious oscillations problem, and a comparison between this semi-Lagrangian method and the Streamline Upwind Petrov Galerkin (SUPG), an stabilizing method of recognized performance. The SUPG method takes the interpolation and the weighting functions in different spaces, creating an effect so that the spurious oscillations are drastically attenuated. The semi-Lagrangean method is a integration factor method, in which the factor is an operator that shifts to a coordinate system that moves with the fluid, but it resets the Lagrangian coordinate system after each time step. This provides stability and the possibility to take bigger time steps. There are many works in the literature analyzing stabilized methods, but they do not analyze the semi-Lagrangian method, which represents the main contribution of this work: to recognize the strengths and weaknesses of the semi-Lagrangian method in convection dominated flows.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os escoamentos altamente convectivos representam um desafio na simulação pelo método de elementos finitos. Com a solução de elementos finitos de Galerkin para escoamentos incompressíveis, a matriz associada ao termo convectivo é não simétrica, e portanto, a propiedade de aproximação ótima é perdida. Na prática as soluções apresentam oscilações espúrias. Muitos métodos foram desenvolvidos com o fim de resolver esse problema. Neste trabalho apresentamos um método semi- Lagrangeano, o qual é implicitamente um método do tipo upwind, que portanto resolve o problema anterior, e comparamos o desempenho do método na solução das equações de convecção-difusão e Navier-Stokes incompressível com o Streamline Upwind Petrov Galerkin (SUPG), um método estabilizador de reconhecido desempenho. No SUPG, as funções de forma e de teste são tomadas em espaços diferentes, criando um efeito tal que as oscilações espúrias são drasticamente atenuadas. O método semi-Lagrangeano é um método de fator de integração, no qual o fator é um operador de convecção que se desloca para um sistema de coordenadas móveis no fluido, mas restabelece o sistema de coordenadas Lagrangeanas depois de cada passo de tempo. Isto prevê estabilidade e a possibilidade de utilizar passos de tempo maiores.Existem muitos trabalhos na literatura analisando métodos estabilizadores, mas não assim com o método semi-Lagrangeano, o que representa a contribuição principal deste trabalho: reconhecer as virtudes e as fraquezas do método semi-Lagrangeano em escoamentos dominados pelo fenômeno de convecção. / Convection dominated flows represent a challenge for finite element method simulation. Many methods have been developed to address this problem. In this work we compare the performance of two methods in the solution of the convectiondiffusion and Navier-Stokes equations on environmental flow problems: the Streamline Upwind Petrov Galerkin (SUPG) and the semi-Lagrangian method. In Galerkin finite element methods for fluid flows, the matrix associated with the convective term is non-symmetric, and as a result, the best approximation property is lost. In practice, solutions are often corrupted by espurious oscillations. In this work, we present a semi- Lagrangian method, which is implicitly an upwind method, therefore solving the spurious oscillations problem, and a comparison between this semi-Lagrangian method and the Streamline Upwind Petrov Galerkin (SUPG), an stabilizing method of recognized performance. The SUPG method takes the interpolation and the weighting functions in different spaces, creating an effect so that the spurious oscillations are drastically attenuated. The semi-Lagrangean method is a integration factor method, in which the factor is an operator that shifts to a coordinate system that moves with the fluid, but it resets the Lagrangian coordinate system after each time step. This provides stability and the possibility to take bigger time steps. There are many works in the literature analyzing stabilized methods, but they do not analyze the semi-Lagrangian method, which represents the main contribution of this work: to recognize the strengths and weaknesses of the semi-Lagrangian method in convection dominated flows.

Purpose: Sweden's construction industry is facing great challenges in form of increased housing with the increasing demands on the environment and economy, this combined with the current low unemployment today and many upcoming retirements. To meet these challenges, it requires development and changes which BIM is considered to handle if it is correct performed. 3d planning is an important part of BIM, where it lays the ground for further step in the building process following two steps, production and management. Method: Selected methods of this thesis is a literature review, semi-structured interviews and document analysis. In the literature review writings about, or related to, 3d planning was studied. The interview method gave more detailed information about the problems that planners experience in reality. The document analysis created a deeper understanding of how 3d design work. Findings: The results show that with simple means it is possible to avoid common problems. Which leads to streamline of 3d design and the entire construction process. This in the form of aspects including economy, the environment and sustainable construction. Implications: Development and improvements in 3d design leads to more effective planning which in contributing to more effective construction. Increase of efficiency can now be justified by the savings in the economy and the environment. But visions of development potential in the further step exists today. One step further, for example, be monitoring the working environment in the planning phase. More education in BIM at all levels of the construction industry should create a better understanding of each other and alleviate the communication gaps that currently prevails. Limitations: This thesis is limited to the design phase of the building process conducted with 3d modeling. / Syfte: Sveriges byggbransch står idag inför stora utmaningar i form av ökat bostadsbyggande med allt högre krav på miljö och ekonomi. Detta i kombination med rådande låg arbetslöshet redan idag och många kommande pensionsavgångar. För att möta dessa utmaningar krävs utveckling och förändring, vilket BIM anses klara om det utförs korrekt. 3d projektering utgör en viktig byggsten inom BIM, där den lägger grunden för vidare arbete i byggprocessens följande två steg som är produktion och förvaltning. Metod: Valda metoder för detta examensarbete är litteraturstudie, semistrukturerad intervju och dokumentanalys. I litteraturstudien studerades litteratur som handlar om eller är relaterade till 3d projektering. Intervjumetoden gav djupare information om problematiken som projektörer upplever i verkligheten. Dokumentanalysen skapade en djupare förståelse hur 3d projektering fungerar. Resultat: Studiens resultat visar att det med hjälp av enkla medel går att undvika vanligt förekommande problem inom 3d projektering för att effektiviseras. Dessa enkla medel är främst förbättrad kommunikation, kompetens och förståelse för varandra. Effektivisering av 3d projektering leder till att öka effektiviteten i hela byggprocessen. Detta med besparingar på bland annat ekonomi, miljö, arbetssäkerhet och hållbart byggande. Konsekvenser: Utveckling och förbättringar inom 3d projektering leder till effektivare projektering som i sin bidrar till effektivare byggprocess. Ökning av effektiviteten kan idag motiveras med besparingar inom ekonomi och miljö. Men visioner om utvecklingspotential i vidare steg finns idag. Ett steg längre kan exempelvis vara kontroll av arbetsmiljön redan i projektering. Mer utbildning inom BIM i alla nivåer för byggbranschen bör skapa en bättre förståelse för varandra och mildra de kommunikationsbrister som idag råder. Begränsningar: Detta examensarbete begränsar sig till projekteringsfasen inom byggprocessen som utförs med 3d modellering.

In this work, we deal with the finite element method Streamline Upwind/Petrov-Galerkin (SUPG) and use it to solve boundary value problem for the stationary convection-diffusion equation with dominant convection with Dirichlet boundary condition on the whole boundary of bounded polyhedral computational domain of dimension 1 and 2, respectively. We consider a quadratic Lagrangian finite elements on the line segments and triangles, respectively. The core of the work is a proposition of choice of stabilizing parameter of SUPG method as an elementwise affine function in outflow boundary layer and as an elementwise constant function in the rest of the computational domain. We show that this choice gives a more accurate solution than the choice of the stabilization parameter as a constant in each element. 1

Radio astronomy is used to study stars, galaxies, black holes and gas clouds radiation at radio frequencies. Detecting extremely weak signals from deep space radio sources requires high sensitive feed system associated with large dish antennas. The key figure of merit is survey speed, or the time required to map a region of the sky to a given source flux density. Survey speed is proportional to the frequency bandwidth, the field of view or observable region of the sky, and the squared sensitivity, where sensitivity is related to reflector aperture efficiency and system noise temperature. Compared to the traditional single feed, phased array feeds with significantly expanded field of view are considered as the next generation feed for radio telescope. This dissertation outlines the design, analysis and measurement of high sensitivity L-band and mm-wave phased array feeds for the 100-meter Green Bank Telescope. Theoretical works for radio astronomy includes design guideline for high sensitivity phased array feed, fundamental frequency bandwidth limit, array antenna loss influenced by mutual coupling and beamformer coefficients and possibility of superdirectivity for radio telescopes and other antennas. These study are helpful to understand and guide the design of a phased array feed system. In the absence of dish antennas, sparse phased arrays with aperiodic structure have been developed for satellite communications. A compromise between the peak side lobe level, array element density, directivity and design complexity is studied. We have found that the array peak side lobe level can be reduced by enhancing the array element direction at the main lobe direction, increasing the array element density and enlarging the array size. A Poynting streamline approach develops to understand the properties of a receiving antenna and the mutual coupling effects between array elements. This method has been successfully used to generate effective area shape for many types of antennas and guide the design of a superdirective antenna. Motivated by this method, a superdirective antenna is experimental demonstrated.