A new version of the Deforming-Spatial-Domain/Stabilized Space--Time (DSD/SST) formulation of incompressible flows has been introduced recently to have additional subgrid-scale representation features. This is the space--time version of the residual-based variational multiscale (VMS) method. The new version is called DSD/SST-VMST (i.e. the version with the VMS turbulence model) and also Space--Time VMS (ST-VMS). The thesis starts with a brief overview of the ST-VMS method. It continues with a comprehensive set of test computations with 3D airfoil geometries at high Reynolds numbers and comparison with experimental data. The thesis shows that the test computations signal a promising future for the ST-VMS method.

A new version of the Deforming-Spatial-Domain/Stabilized Space--Time (DSD/SST) formulation of incompressible flows has been introduced recently to have additional subgrid-scale representation features. This is the space--time version of the residual-based variational multiscale (VMS) method. The new version is called DSD/SST-VMST (i.e. the version with the VMS turbulence model) and also Space--Time VMS (ST-VMS). The thesis starts with a brief overview of the ST-VMS method. It continues with a comprehensive set of test computations with 3D airfoil geometries at high Reynolds numbers and comparison with experimental data. The thesis shows that the test computations signal a promising future for the ST-VMS method.

In contemporary debates on space, the validity of &amp / #8216 / physical space&amp / #8217 / as an indispensable category of human existence is widely questioned on the basis of the claim that the relevant interval of analysis has shifted from &amp / #8216 / space&amp / #8217 / to &amp / #8216 / time&amp / #8217 / , thanks to the technological innovations enabling the speed of present-day telecommunications. The apparent primacy of mobility of deterritorialized commodities, signs, meanings, and identities, in the contemporary society, adds new dimensions to the traumatic experience of ephemerality, in spatial and temporal categories. Through the claims declaring, the dissolution of the dichotomy between urban and rural, and redefinition of the relevant dichotomy between the &amp / #8216 / space of places&amp / #8217 / and the &amp / #8216 / space of flows&amp / #8217 / in recent theoretical efforts / we attempt to trace how the notion of &amp / #8216 / place&amp / #8217 / could be revalidated and reconstituted with reference to processes of contemporary globalization. The study examines the new paths for a constructive definition of &amp / #8216 / place&amp / #8217 / , which are opened up by the crisis in locating and representing temporal and spatial categories both physically and mentally.

Aquesta tesi doctoral proposa formulacions de Galerkin discontinu (DG) d'alt ordre per fluxos viscosos incompressibles. Es desenvolupa un nou mètode de DG amb penalti interior (IPM-DG), que condueix a una forma feble simètrica i coerciva pel terme de difusió, i que permet assolir una aproximació espacial d'alt ordre. Aquest mètode s'aplica per resoldre les equacions de Stokes i Navier-Stokes. L'espai d'aproximació de la velocitat es descompon dins de cada element en una part solenoidal i una altra irrotacional, de manera que es pot dividir la forma dèbil IPM-DG en dos problemes desacoblats. El primer permet el càlcul de les velocitats i de les pressions híbrides, mentre que el segon calcula les pressions en l'interior dels elements. Aquest desacoblament permet una reducció important del número de graus de llibertat tant per velocitat com per pressió. S'introdueix també un paràmetre extra de penalti resultant en una formulació DG alternativa per calcular les velocitats solenoidales, on les pressions no apareixen. Les pressions es poden calcular com un post-procés de la solució de les velocitats. Es contemplen altres formulacions DG, com per exemple el mètode Compact Discontinuous Galerkin, i es comparen al mètode IPM-DG. Es proposen mètodes implícits de Runge-Kutta d'alt ordre per problemes transitoris incompressibles, permetent obtenir esquemes incondicionalment estables i amb alt ordre de precisió temporal. Les equacions de Navier-Stokes incompressibles transitòries s'interpreten com un sistema de Equacions Algebraiques Diferencials, és a dir, un sistema d'equacions diferencials ordinàries corresponent a la equació de conservació del moment, més les restriccions algebraiques corresponent a la condició d'incompressibilitat. Mitjançant exemples numèrics es mostra l'aplicabilitat de les metodologies proposades i es comparen la seva eficiència i precisió. / This PhD thesis proposes divergence-free Discontinuous Galerkin formulations providing high orders of accuracy for incompressible viscous flows. A new Interior Penalty Discontinuous Galerkin (IPM-DG) formulation is developed, leading to a symmetric and coercive bilinear weak form for the diffusion term, and achieving high-order spatial approximations. It is applied to the solution of the Stokes and Navier-Stokes equations. The velocity approximation space is decomposed in every element into a solenoidal part and an irrotational part. This allows to split the IPM weak form in two uncoupled problems. The first one solves for velocity and hybrid pressure, and the second one allows the evaluation of pressures in the interior of the elements. This results in an important reduction of the total number of degrees of freedom for both velocity and pressure. The introduction of an extra penalty parameter leads to an alternative DG formulation for the computation of solenoidal velocities with no presence of pressure terms. Pressure can then be computed as a post-process of the velocity solution. Other DG formulations, such as the Compact Discontinuous Galerkin method, are contemplated and compared to IPM-DG. High-order Implicit Runge-Kutta methods are then proposed to solve transient incompressible problems, allowing to obtain unconditionally stable schemes with high orders of accuracy in time. For this purpose, the unsteady incompressible Navier-Stokes equations are interpreted as a system of Differential Algebraic Equations, that is, a system of ordinary differential equations corresponding to the conservation of momentum equation, plus algebraic constraints corresponding to the incompressibility condition. Numerical examples demonstrate the applicability of the proposed methodologies and compare their efficiency and accuracy.

Nyckelord: Kassaflödesanalys, kassaflöde, likviditetsplanering, likviditetsbudget, likviditetsprognos, likviditet och nyckeltal. Frågeställning: Hur och varför använder de fyra valda organisationerna kassaflödesanalyser och -prognoser internt? Vilka är skillnaderna i de fyra organisationernas sätt att ställa upp och använda sig av kassaflödesanalyserna och -prognoserna och beror skillnaderna på i vilken bransch de verkar? Syfte: Syftet med uppsatsen är att undersöka hur kassaflödesanalyser och -prognoser tillämpas praktiskt i de fyra stora organisationerna ABB, Västerås stad, Manpower och Gina Tricot för att identifiera om skillnader i uppförandet finns. Metod: Studien är av kvalitativ karaktär då fallstudierna av organisationerna gjordes genom intervjuer med representanter på respektive organisation. Totalt genomfördes elva intervjuer med tolv personer. Data till referensramen samlades in genom sekundära källor. Insamlad data och information analyserades där referensram och empiri sattes i relation till varandra. Slutsats: Brister i metoden för hur kassaflödesanalysen ska upprättas finns då den i praktiken inte används av de undersökta organisationerna internt. Då den ändå måste upprättas på grund av lagstiftningen bör en förändring av uppställandet göras så att denna ska kunna användas mer internt. Då majoriteten av organisationerna i undersökningen gör prognoser istället för likviditetsbudget, vid likviditetsplanering, behöver forskningen inom referensramen för ämnet fokuseras på att förbättra prognosberäkningar. Studien visar på att användandet av likviditetsplanering, analys av kassaflöde, prognoser och nyckeltal kan bero på om organisationen är verksam inom privat eller offentlig sektor. / Keywords: Statement of cash flows, cash flow, cash forecast, cash flow projection, liquidity and ratio. Research question: How and why do the four organizations use the statement of cash flows and cash flow forecasts internally? Which differences are shown regarding the four organizations way of presenting and using the statement of cash flows and cash flow forecasts, and do these differences depend on the type of business? Purpose: The purpose of this study is to examine how the statement of cash flows and cash flow forecasts are used in the four large organizations ABB, Manpower, Gina Tricot and City of Västerås to identify if there are differences. Method: This quantitative study was based on twelve interviews with eleven different persons. The frame of reference was written with secondary data as material. Then collected information was processed, the frame of reference and the empirics were put together and then all was analyzed. Conclusion: There appears to be flaws in the method, in which the statement of cash flows is to be presented, because it is overall not used by organizations internally. Because the organizations are bound by law to do it a change in the method has to be made so it can be used more internally. The research of liquidity planning needs to be focused on improving the methods of calculating forecasts because the majority of the organizations in this study use forecasts to plan liquidity instead of liquidity budgets. The study shows that the use of plans of liquidity, analysis of cash flow, forecasts and ratios can depend on if the organization is private or public.

This thesis makes significant contributions to the object detection problem in computer vision. The object detection problem is, given a digital image of a scene, to detect the relevant object in the image. One technique for performing object detection, called ``active contours,' optimizes a constructed energy that is defined on contours (closed curves) and is tailored to image features. An optimization method can be used to perform the optimization of the energy, and thereby deform an initially placed contour to the relevant object. The typical optimization technique used in almost every active contour paper is evolving the contour by the energy's gradient descent flow, i.e., the steepest descent flow, in order to drive the initial contour to (hopefully) the minimum curve. The problem with this technique is that often times the contour becomes stuck in a sub-optimal and undesirable local minimum of the energy. This problem can be partially attributed to the fact that the gradient flows of these energies make use of only local image and contour information. By local, we mean that in order to evolve a point on the contour, only information local to that point is used. Therefore, in this thesis, we introduce a new class of flows that are global in that the evolution of a point on the contour depends on global information from the entire curve. These flows help avoid a number of problems with traditional flows including helping in avoiding undesirable local minima. We demonstrate practical applications of these flows for the object detection problem, including applications to both image segmentation and visual object tracking.

Boundary layer calculations are performed around an airfoil and its wake. Smith-van Ingen transition prediction method is employed to find the transition from laminar to turbulent flow. First, potential flow around the airfoil is solved with the Hess-Smith panel method. The resulting velocity distribution is input to the boundary layer equations in order to find a so called blowing velocity distribution. The output of the boundary layer equations are also used to compute the location of onset of transition using the Smith-van Ingen en transition prediction method. The obtained blowing velocity distribution is fed back to the panel method to find a velocity distribution which includes the effects of viscosity. The procedure described is repeated until convergence is observed. A computer program is developed using the theory. Results obtained are in good accord with measurements

This study considers bicriteria approaches to the minimum cost network flow problem and a rescheduling problem where those approaches find their applications. For the bicriteria integer minimum cost network flow problem, we generate all efficient solutions in two phases. The first phase generates the extreme supported efficient points that are the extreme points of the objective space of the continuous bicriteria network flow problem. In the second phase, we generate the nonextreme supported and unsupported efficient points by Integer Programming Based approaches. Our rescheduling problem considers parallel unrelated machine environments. The criteria are the total flow time as an efficiency measure and the total reassignment cost as a stability measure. We show that the problems that address linear functions of the two criteria can be represented by bicriteria network flow models. To generate all efficient solutions, we use a Classical Approach that is based on the optimal solutions of the singly constrained network flow problem and provide a Branch and Bound approach that starts with extreme supported efficient set and uses powerful bounds. To find an optimal solution to any nonlinear function of the two criteria, we provide a Branch and Bound approach and an Integer Programming Based approach that eliminates some portions of the efficient set that cannot provide improved solutions. We contribute both to the network flow and scheduling literature by proposing algorithms to the bicriteria network flow models and applying them to a rescheduling problem that is bicriteria in nature. The results of our extensive computations with up to 100 jobs and 12 machines have revealed that, the Branch and Bound algorithm finds the efficient set in less computational effort compared to the classical approach. In minimizing a nonlinear function of the two criteria both IP Based approach and Branch and Bound algorithm perform quite satisfactory.

A non-iterative pressure based algorithm which consists of splitting the solution of momentum energy and species equations into a sequence of predictor-corrector stages was developed for the simulation of transient reacting radiating flows. A semi-discrete approach called the Method of Lines (MOL) which enables implicit time-integration at all splitting stages was used for the solution of conservation equations. The solution of elliptic pressure equation for the determination of pressure field was performed by a multi-grid solver (MUDPACK package). Radiation calculations were carried out by coupling previously developed gray and non-gray radiation models with the algorithm. A first order (global) reaction mechanism was employed to account for the chemistry. The predictions of the algorithm for the following test cases: i) non-isothermal turbulent pipe flow and ii) laminar methane-air diffusion flame / were benchmarked against experimental data and numerical solutions available in the literature and the capability of the code to predict transient solutions was demonstrated on these test cases. Favorable agreements were obtained for both test cases. The effect of radiation and non-gray treatment of the radiative properties were investigated on the second test case. It was found that incorporation of radiation has significant effect on Temeprature and velocity fields but its effect is limited in species predictions. Executions with both radiation models revealed that the non-gray radiation model considered in the present study produces similar results with the gray model at a considerably higher computational cost. The algorithm developed was found to be an efficient and versatile tool for the timedependent simulation of different flow scenarios constitutes the initial steps towards the computation of transient turbulent combustion.

In this thesis, gas-kinetic methods for inviscid and viscous flow simulations are developed. Initially, the finite volume gas-kinetic methods are investigated for 1-D flows as a preliminary study and are discussed in detail from theoretical and numerical points of view. The preliminary results show that the gas-kinetic methods do not produce any unphysical flow phenomena. Especially the Gas-Kinetic BGK method, which takes into account the particle collisions, predicts compressible flows accurately. The Gas-Kinetic BGK method is then extended for the solution of 2-D and 3-D inviscid and viscous flows on unstructured/hybrid grids. The computations are performed in parallel. Various inviscid and viscous test cases are considered and it is shown that the Gas-Kinetic BGK method predicts both inviscid and viscous flow fields accurately. The implementation of hybrid grids for viscous flows reduces the overall number of grid cells while enabling the resolution of boundary layers. The parallel computations significantly improve the computation time of the Gas-Kinetic BGK method which, in turn, enable the method for the computation of practical aerodynamic flow problems.