Time integration methods are necessary for the solution of transient flow problems. In recent years, interest in transient flow problems has increased, leading to a need for better understanding of the costs and benefits of various time integration schemes. The present work investigates two common time integration schemes, namely the Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) and the Fractional Step (FS) method. Three two-dimensional, transient, incompressible flow problems are solved using a cell centered, finite volume code. The three test cases are laminar flow in a lid-driven skewed cavity, laminar flow over a square cylinder, and turbulent flow over a square cylinder. Turbulence is modeled using wall functions and the k - ε turbulence model with the modifications suggested by Kato and Launder. Solution efficiency as measured by the effort carried out by the flow equation solver and CPU time is examined. Accuracy of the results, generated using the SIMPLE and FS time integration schemes, is analyzed through a comparison of the results with existing experimental and/or numerical solutions. Both the SIMPLE and FS algorithms are shown to be capable of solving benchmark flow problems with reasonable accuracy. The two schemes differ slightly in their prediction of flow evolution over time, especially when simulating very slowly changing flows. As the time step size decreases, the SIMPLE algorithm computational cost (CPU time) per time step remains approximately constant, while the FS method experiences a reduction in cost per time step. Also, the SIMPLE algorithm is numerically stable for time steps approaching infinity, while the FS scheme suffers from numerical instability if the time step size is too large. As a result, the SIMPLE algorithm is recommended to be used for transient simulations with large time steps or steady state problems while the FS scheme is better suited for small time step solutions, although both time-stepping schemes are found to be most efficient when their time steps are at their maximum stable value.

The purpose of this thesis is to develop corotational beam elements for the nonlinear dynamic analyse of flexible beam structures. Whereas corotational beam elements in statics are well documented, the derivation of a corotational dynamic formulation is still an issue. In the first journal paper, an efficient dynamic corotational beam formulation is proposed for 2D analysis. The idea is to adopt the same corotational kinematic description in static and dynamic parts. The main novelty is to use cubic interpolations to derive both inertia terms and internal terms in order to capture correctly all inertia effects. This new formulation is compared with two classic formulations using constant Timoshenko and constant lumped mass matrices. In the second journal paper, several choices of parametrization and several time stepping methods are compared. To do so, four dynamic formulations are investigated. The corotational method is used to develop expressions of the internal terms, while the dynamic terms are formulated into a total Lagrangian context. Theoretical derivations as well as practical implementations are given in detail. Their numerical accuracy and computational efficiency are then compared. Moreover, four predictors and various possibilities to simplify the tangent inertia matrix are tested. In the third journal paper, a new consistent beam formulation is developed for 3D analysis. The novelty of the formulation lies in the use of the corotational framework to derive not only the internal force vector and the tangent stiffness matrix but also the inertia force vector and the tangent dynamic matrix. Cubic interpolations are adopted to formulate both inertia and internal local terms. In the derivation of the dynamic terms, an approximation for the local rotations is introduced and a concise expression for the global inertia force vector is obtained. Four numerical examples are considered to assess the performance of the new formulation against two other ones based on linear interpolations. Finally, in the fourth journal paper, the previous 3D corotational beam element is extended for the nonlinear dynamics of structures with thin-walled cross-section by introducing the warping deformations and the eccentricity of the shear center. This leads to additional terms in the expressions of the inertia force vector and the tangent dynamic matrix. The element has seven degrees of freedom at each node and cubic shape functions are used to interpolate local transversal displacements and axial rotations. The performance of the formulation is assessed through five examples and comparisons with Abaqus 3D-solid analyses. / <p>QC 20131017</p>

Computational fluid dynamics (CFD) is a significant tool routinely used indesign and optimization in aerospace industry. Often cases with unsteadyflows must be computed, and the long compute times of standard methods hasmotivated the present work on new implicit methods to replace the standardexplicit schemes. The implementation and numerical experiments were donewith the Swedish national flow solver Edge, developed by FOI,universities, and collaboration partners.The work is concentrated on a Lower-Upper Symmetric Gauss-Seidel (LU-SGS)type of time stepping. For the very anisotropic grids needed forReynolds-Averaged Navier-Stokes (RANS) computations of turbulent boundary layers,LU-SGS is combined with a line-implicit technique.  The inviscid flux Jacobians which contribute to the diagonalblocks of the system matrix are based on a flux splitting method with upwind type dissipation giving  control over diagonal dominance and artificial dissipation.The method is  controlled by several parameters, and comprehensivenumerical experiments were carried out to identify their influence andinteraction so that close to optimal values can be suggested. As an example,the optimal number of iterations carried out in a time-step increases with increased resolution of the computational grid.The numbering of the unknowns is important, and the numberings produced by mesh generators of Delaunay- and advancing front-type wereamong the best.The solver has been parallelized with the Message Passing Interface (MPI) for runs on multi-processor hardware,and its performance scales with the number of processors at least asefficiently as the explicit methods. The new method saves typicallybetween 50 and 80 percent of the runtime, depending on the case, andthe largest computations have reached 110M grid nodes. Theclassical multigrid acceleration for 3D RANS simulations was foundineffective in the cases tested in combination with the LU-SGS solverusing optimal parameters. Finally, preliminary time-accurate simulations for unsteady flows have shown promising results. / <p>QC 20141201</p>

Abstract The primary focus of this research project was an evaluation of the Group Stepping Stones Triple P parenting program for parents of a child with a disability. In addition there was an investigation into the similarities and differences in child behaviour and parenting experience, and program outcomes, for families of children with different developmental disabilities. While the Triple P Positive Parenting Program has an impressive evidence base (Sanders, 1999; Sanders, Markie-Dadds, Tully & Bor, 2000) and research indicates that the standard Stepping Stones Triple P Program is efficacious for different disability groups (Roberts, Mazzucchelli, Studman & Sanders, 2006) and for parents of children with Autistic Spectrum Disorders (Whittingham, Sofronoff, Sheffield & Sanders, 2009), to date the group version of Stepping Stones Triple P has not been comprehensively evaluated, nor the efficacy of the program evaluated when administered concurrently to parents of children with different developmental disabilities. Currently, there is a lack of participant-friendly, evidence-based group parenting programs that can be utilised in a cost-effective manner with all parents of children with disabilities. Many interventions have been designed specifically to cater to the requirements of a particular disability group. While there is some divergence in disability characteristics and in the experience of families of children with different disabilities, there is compelling evidence that many of the most challenging experiences faced by parents of disabled children (such as emotional and behavioural disturbance and delays in skill development) are shared by many disability populations (Raina et al., 2005; Bourke et al., 2008). Consequently there is empirical support for the implementation of a broad, skill-based parenting program for all parents of children with disabilities. The first study in this research project was a randomised controlled trial the Group Stepping Stones Triple P program for parents of children with Autism Spectrum Disorders (ASD), Down syndrome, other intellectual disabilities and Cerebral Palsy. Fifty-two families were included in this trial and were randomly allocated to treatment and wait-list control groups. The results demonstrate significant improvements in child behaviour and parenting difficulties that were maintained at follow-up six months later. For over a third of participants the change in child behaviour and parenting styles was clinically reliable (Jacobsen & Truax, 1991; Evans, Margison & Barkham, 1998). In addition, the majority of parents reported the attainment of their program goals following the intervention. The second study was a comparison of program outcomes for parents from different disability groups. The sample was divided into two groups; parents of children with ASD and parents of children with intellectual and physical disabilities. The results demonstrated significant improvements in child behaviour and parenting difficulties from pre- to post-intervention for both the ASD group and the Intellectual and Physical disability group. For a third of parents in the ASD group and over a third of parents in the Intellectual and Physical disability group, the changes were clinically reliable (Jacobsen & Truax, 1991; Evans et al., 1998). In addition, the means for both groups on the child behaviour, parenting style and parental psychological functioning variables were compared. The results indicated that there were some differences in child behaviour, parenting styles and parent distress between the two groups, and in the program goals set by parents. However, overall the results revealed no systematic differences in treatment outcomes across disability groups, demonstrating that the program was effective for families of children with ASD and families of children with Intellectual and Physical disabilities. Finally, a series of three case evaluations were conducted to examine program outcomes and differences in child behaviour and parenting experiences for the families of a child with ASD, Down syndrome and Cerebral palsy. The results of the case studies revealed significant improvements in child behaviour and parenting styles for all three families, along with high levels of program satisfaction and successful attainment of parenting goals. For all three families these changes in child behaviour and parenting style were clinically reliable (Jacobsen & Truax, 1991; Evans et al., 1998) and maintained at six-month follow up. The results also provided information about the similarities and differences in parenting experiences, child behaviour and program goals across the three disabilities. Overall, this research project has demonstrated that the Group Stepping Stones Triple P program is an effective parenting intervention for challenging behaviour and dysfunctional parenting in families of children with a range of developmental disabilities. The results of this research provide evidence to suggest that mixed disability group format used in the administration of the Group Stepping Stones Triple P program did not preclude positive program outcomes. Finally, the results of this research project indicate that there are many shared parenting experiencing across families of children with different disabilities and that regardless of observed differences in disability characteristics and family experiences, the Group Stepping Stones Triple P program is sufficiently flexible and comprehensive in its scope to meet the needs of families from different disability populations.

Du fait de sa robustesse et de son faible coût, la machine synchro-réluctante (MSR) constitue une alternative intéressante à la machine asynchrone. A pertes égales, une MSR bien optimisée offre un couple et par suite un rendement plus élevés. Ainsi, la MSR est très compétitive pour les applications à haute vitesse, à forte puissance ou à haute température. Cette thèse se propose d’optimiser les machines synchro-réluctantes à rotor massif et avec barrières de flux pour produire le maximum de couple avec un facteur de puissance le plus élevé possible. Pour cela, une modélisation originale utilisant des réseaux de perméances non linéaires a été mise au point pour les deux types de MSR. Les modèles proposés sont significativement plus rapides et aussi précis que les modèles par éléments finis. De plus, la réalisation d’un prototype à barrières de flux a permis de les valider expérimentalement. / Because of its robustness and its low cost, the synchronous reluctance motor (SynRM) is an interesting alternative to the induction motor. At equal losses, a correctly optimized SynRM offers a higher torque and then a higher efficiency. Thus, the SynRM is very comptetitive for high speed, high power or high temperature applications. This thesis intends to optimize massive rotor and flux barrier rotor SynRM to produce the maximum torque with the highest possible power factor. For this purpose, an original non linear reluctance network modeling of synchronous reluctance motors with a massive or a flux barrier rotor was developed. The proposed models are significantly faster than the finite element ones and take accurately into account the saturation of all ferromagnetic parts of the motor. The construction of a flux barrier rotor prototype allowed an experimental validation of the modeling approach.

The high competitiveness between companies, the projects complexity, the machinery modernization, the production flexibility and the costs reduction, lead small and medium companies to aim new diversification of equipments and products to maintain themselves in a worldwide market. One way of seeking a better mechanic production concerning these aspects is using the equipments of the Computerized Numeric Command (CNC). This paper has the objective of creating a computerized tool (a software) that works as a Computerized Numeric Command unit. The system has the function of controlling the communication with the machine devices, and it also works to make possible the creation or usage of a text file with a CNC programming, to interpret, analyze, simulate and execute the information of a preprogrammed sequence of operations (CNC programming). The implementation of the control functions, of the equipment operation resources, of the software CNC simulation on a graphic screen and of the techniques of linear and circle interpolation showed the viability of the personal computers (PCs) application as a command unit developing the CNC machines with stepping motor starting. / A alta competitividade entre as empresas, a complexidade de projetos, a modernização de maquinário, a flexibilidade da produção e a redução de custos, levam as pequenas e médias empresas a buscar novos equipamentos e diversificação de produtos para se manterem no mercado globalizado. Uma forma de buscar a melhoria da produção mecânica nesses aspectos é através da utilização de equipamentos de Comando Numérico Computadorizado (CNC). Esse trabalho tem o objetivo da criação de uma ferramenta computacional (programa) que opere como uma unidade de Comando Numérico Computadorizado. O sistema tem como função controlar a comunicação com os dispositivos da máquina, bem como possibilitar a criação ou utilização de um arquivo de texto com a programação CNC, interpretar, analisar, simular e executar as informações de uma seqüência pré-programada de operações (programação CNC). A implementação de funções de controle, de recursos de operação do equipamento, de simulação do programa CNC em tela gráfica e de técnicas de interpolação linear e circular, mostrou a viabilidade de aplicação de microcomputadores pessoais (PCs) como unidade de comando no desenvolvimento de máquinas CNC com acionamento por motores de passo.

The objective of this work is to develop a methodology to control of equipments powered by stepping motors, via the computer parallel port, with up to three programmable axes, for use in automated processes. To implement the proposed system, used to be an environment for developing computer programs, which could make communication with the computer's parallel port for data transfer control circuits to drive the stepping motors. The program developed has the following functions: priority for implementing the process in the microcomputer operating system, interpretation of sequences of planned operations through data files, view the data file to control the equipment during its implementation; view realtime control data sent to the parallel port, manual and automatic control of equipment, implementation of reverse form of movements applied to the axes of equipment, adjustment of speed of the movement axes of the equipment in automatic or manual and online help system. Important features presented by the proposed system is the precision control of speed, the ability to store different settings for different equipment, possibility of playing in an automatic way to 100 times an operation planned by facilitating mass production, and capacity to store a sequence of manual commands, enabling the program by learning. Practical tests of operation of the system demonstrated the feasibility of applying the technique in cases that require programmable automation. / O objetivo deste trabalho é desenvolver uma metodologia de controle de equipamentos acionados por motores de passo, via porta paralela de microcomputadores, com até três eixos programáveis, para utilização em processos de automação. Para implementar o sistema proposto, utilizou-se um ambiente de desenvolvimento de programas computacionais, através do qual foi possível fazer a comunicação com a porta paralela do computador para transferência de dados de controle aos circuitos de acionamento dos motores de passos. O programa desenvolvido possui as seguintes funções: prioridade de execução do processo no sistema operacional do microcomputador; interpretação de seqüências de operações programadas através de arquivos de dados; visualização do arquivo de dados para controle do equipamento durante sua execução; visualização em tempo real dos dados de controle enviados à porta paralela; controle manual e automático do equipamento; execução de forma reversa dos movimentos aplicados aos eixos do equipamento; ajuste de velocidade dos eixos de movimento do equipamento de forma automática ou manual; e sistema de ajuda online. Características importantes apresentadas pelo sistema proposto são a precisão no controle da velocidade, a capacidade de armazenar configurações diversas para diferentes equipamentos, possibilidade de reproduzir de forma automática até 100 vezes uma operação programada, facilitando a produção em série e capacidade de armazenar uma seqüência de comandos manuais, possibilitando a programação por aprendizagem. Testes práticos de operação do sistema demonstraram a viabilidade de aplicação da técnica em processos que demandam automação programável.

The Swedish regulation concerning fixed-term contract has been a topic for discussion during the last decade. It has been criticised for not following the council’s directive 1999/70/EG on the measures to prevent the abuse of fixed-term contracts. Since 2016 the regulation has changed. It has changed in order to have the legislation within the purpose and measures set in the fixed-term directive. This essay aims to clarify whether the new Swedish legislation is in accordance with the framework agreement attached to the directive on fixed-term contracts. This will be done by analysing the measures established in the framework agreement and the purpose of the directive, then compare the result with the Swedish legislation. This part of the essay will be written using the legal dogmatic methodology. Since fixed-term contracts are more common among young people this essay will focus on how fixed-term contract, and regulations on fixed-term contracts, will affect the position of young people in the labour market. It is obvious that there are some difficulties to harmonize a legislation that suits all the social partners on the labour market. In fact, it can almost be impossible. By illuminate the political discussion regarding the use of fixed-term contracts it will help to understand why this matter is so complex and how it can be a stepping stone or a dead-end job. This will be done with a legal policy method.

L’objectif de cette thèse est de proposer des éléments finis poutres corotationnels 2D et 3D pour l’analyse du comportement dynamique non-linéaire des structures à barres. La contribution majeure de cette thèse est l’utilisation de fonctions d’interpolations cubiques à la fois pour la détermination de l’expression des efforts internes mais aussi celle des termes d’inertie. En négligeant le carré du déplacement transversal dans le repère local, une expression analytique des termes dynamiques en 2D est obtenue. Sur base d’une étude comparative approfondie sur la paramétrisation des rotations et les algorithmes d’intégration temporelle et d’une approximation des rotations locales, nous proposons deux éléments finis poutre 3D précis et robustes. Contrairement au premier, le second élément 3D prend en compte les déformations de gauchissement et l'excentricité du centre de cisaillement. Les diverses comparaisons réalisées démontrent la pertinence des formulations proposées. / The purpose of this thesis is to propose several corotational beam formulations for both 2D and 3D nonlinear dynamic analyse of flexible structures. The main novelty of these formulations is that the cubic interpolation functions are used to derive not only the internal force vector and the tangent stiffness matrix but also the inertial force vector and the dynamic matrix. By neglecting the quadratic terms of the local transversal displacements, closed-form expressions for the inertial terms are obtained for 2D problems. Based on an extensive comparative study of the parameterizations of the finite rotations and the time stepping method, and by adopting an approximation of the local rotations, two consistent and effective beam formulations for 3D dynamics are developed. In contrast with the first formulation, the second one takes into account the warping deformations and the shear center eccentricity. The accuracy of these formulations is demonstrated through several numerical examples.

Wave phenomena appear in many fields of science such as acoustics, geophysics, and quantum mechanics. They can often be described by partial differential equations (PDEs). As PDEs typically are too difficult to solve by hand, the only option is to compute approximate solutions by implementing numerical methods on computers. Ideally, the numerical methods should produce accurate solutions at low computational cost. For wave propagation problems, high-order finite difference methods are known to be computationally cheap, but historically it has been difficult to construct stable methods. Thus, they have not been guaranteed to produce reasonable results. In this thesis we consider finite difference methods on summation-by-parts (SBP) form. To impose boundary and interface conditions we use the simultaneous approximation term (SAT) method. The SBP-SAT technique is designed such that the numerical solution mimics the energy estimates satisfied by the true solution. Hence, SBP-SAT schemes are energy-stable by construction and guaranteed to converge to the true solution of well-posed linear PDE. The SBP-SAT framework provides a means to derive high-order methods without jeopardizing stability. Thus, they overcome most of the drawbacks historically associated with finite difference methods. This thesis consists of three parts. The first part is devoted to improving existing SBP-SAT methods. In Papers I and II, we derive schemes with improved accuracy compared to standard schemes. In Paper III, we present an embedded boundary method that makes it easier to cope with complex geometries. The second part of the thesis shows how to apply the SBP-SAT method to wave propagation problems in acoustics (Paper IV) and quantum mechanics (Papers V and VI). The third part of the thesis, consisting of Paper VII, presents an efficient, fully explicit time-integration scheme well suited for locally refined meshes.