Electricity has always had a great impact on our daily life. It plays an important role in every aspect  of  society,  economy,  and  technology  of  every  nation.  Sweden  among  other  Nordic countries has always strived to improve its energy landscape. Currently, Nuclear power and Hydroelectricity  are  the  main  methods  of  energy  generation  in  this  country.  Together  with exploring  new  ways  of  generating  energy  without  dependency  on  nuclear  power,  Sweden also  expresses  an  interest  in  encouraging  households  and  companies  to  use  energy  in  an efficient way in order to reduce energy  consumption and its associated costs. The scope of this thesis is to review and evaluate various state-of-the-art data analysis tools and algorithms to  generate  a  meaningful  consumer  behaviour  model  based  on  the  electricity  usage  data collected   from   households   in   several   areas   of   Sweden.   Understanding   the   demand characteristics  for  electricity  would  give  electric  suppliers  more  power  in  shaping  their marketing strategies as well as setting appropriate electricity pricing.

Embroidery is a traditional non-photorealistic art form in which threads of different colours stitched into a base material are used to create an image. This thesis presents techniques for automatically producing embroidery layouts from line drawings and for rendering those layouts in real time on potentially deformable 3D objects with hardware acceleration. Layout of stitches is based on automatic extraction of contours from line drawings followed by a set of stitch-placement procedures based on traditional embroidery techniques. Rendering first captures the lighting environment on the surface of the target object and renders it as an image in texture space. Stitches are rendered in this space using a lighting model suitable for threads at a resolution that avoids geometric and highlight aliasing. It is also possible to render stitches in layers to capture the 2.5D nature of embroidery. A filtered texture pyramid is constructed from the resulting texture and applied to the 3D object. Aliasing of fine stitch structure and highlights is avoided by this process. The result is a realistic embroidered image that properly responds to lighting.

Lakes comprise a large portion of the surface cover in northern North America, forming an important part of the cryosphere. Further alterations to the present day ice regime could result in major ecosystem changes, such as species shifts and the disappearance of perennial ice cover. Lake ice has been shown to both respond to, and play a role in the local/regional climate. The timing of lake ice phenological events (e.g. break-up/freeze-up) is a useful indicator of climate variability and change. Trends in ice phenology have typically been associated with variations in air temperatures while trends found in ice thickness tend to be associated more with changes in snow cover. The inclusion of lakes and lake ice in climate modelling is an area of increased attention in recent studies and the ability to accurately represent ice cover on lakes will be an important step in the improvement of global circulation models, regional climate models and numerical weather forecasting. This thesis aimed to further our understanding of lake ice and climate interactions, with an emphasis on ice cover modelling. The Canadian Lake Ice Model (CLIMo) was used throughout for lake ice simulations. To validate and improve the model results, in situ measurements of the ice cover for two seasons in Churchill, MB were obtained using an upward-looking sonar device Shallow Water Ice Profiler (SWIP) installed on the bottom of the lake. The SWIP identified the ice-on/off dates as well as collected ice thickness measurements. In addition, a digital camera was installed on shore to capture images of the ice cover through the seasons and field measurements were obtained of snow depth on the ice, and both the thickness of snow ice (if present) and total ice cover. Altering the amounts of snow cover on the ice surface to represent potential snow redistribution affected simulated freeze-up dates by a maximum of 22 days and break-up dates by a maximum of 12 days, highlighting the importance of accurately representing the snowpack for lake ice modelling. The late season ice thickness tended to be under estimated by the simulations with break-up occurring too early, however, the evolution of the ice cover was simulated to fall between the range of the full snow and no snow scenario, with the thickness being dependent on the amount of snow cover on the ice surface. CLIMo was then used to simulate lake ice phenology across the North American Arctic from 1961–2100 using two climate scenarios produced by the Canadian Regional Climate Model (CRCM). Results from the 1961–1990 time period were validated using 15 locations across the Canadian Arctic, with both in situ ice cover observations from the Canadian Ice Database as well as additional ice cover simulations using nearby weather station data. Projected changes to the ice cover using the 30-year mean data between 1961–1990 and 2041–2070 suggest a shift in break-up and freeze-up dates for most areas ranging from 10–25 days earlier (break-up) and 0–15 days later (freeze-up). The resulting ice cover durations show mainly a 10–25 day reduction for the shallower lakes (3 and 10 m) and 10–30 day reduction for the deeper lakes (30 m). More extreme reductions of up to 60 days (excluding the loss of perennial ice cover) were shown in the coastal regions compared to the interior continental areas. The mean maximum ice thickness was shown to decrease by 10–60 cm with no snow cover and 5–50 cm with snow cover on the ice. Snow ice was also shown to increase through most of the study area with the exception of the Alaskan coastal areas. While the most suitable way to undertake wide scale lake ice modeling is to force the models with climate model output or reanalysis data, a variety of different lake morphometric conditions could exist within a given grid cell leading to different durations of ice cover within the grid cell. Both the daily IMS product (4 km) and the MODIS snow product (500 m) were assessed for their utility at determining lake ice phenology at the sub-grid cell level throughout the province of Quebec. Both products were useful for detecting ice-off, however, the MODIS product was advantageous for detecting ice-on, mainly due to the finer resolution and resulting spatial detail of the lake ice. The sub-grid cell variability was typically less than 2%, although it ranged as high as 10% for some grid cells. An indication of whether or not the simulated ice-on/off dates were within the sub-grid cell variability was determined and on average across the entire province, were found to be within the variability 62% of the time for ice-off and 80% of the time for ice-on. Forcing the model with the future climate scenarios from CRCM predicts ice cover durations throughout the region will decrease by up to 50 days from the current 1981-2010 means to the 2041-2070 means, and decrease from 15 to nearly 100 days shorter between the contemporary and 2071-2100 means. Overall, this work examined the climate-lake-ice interactions under both contemporary and future climate conditions, as well as provided new insight into sub-grid cell variability of lake ice.

The diffusional transformation kinetics of C-Mn steels during continuous cooling have been measured and predicted in this study for predicting the non-isothermal multi-stage cooling transformation kinetics. A suitable thermodynamic model is assessed for determining the driving force of austenite to ferrite transformation and the austenite/ferrite interface concentrations under various equilibrium constraints, which are essential to determine the diffusion-controlled transformation kinetics. The continuous cooling transformation (CCT) curves of C-Mn steels are determined using dilatometric method. Pham¡¦s empirical growth model is found most suitable for describing the start and finish transformation curve. The Avrami equation, common-used for isothermal transformation, is found to be applicable to the continuous cooling transformation. The Avrami exponents, nF and nP, for ferrite- and pearlite- dominant CCT, respectively, are close to the isothermal ones reported in the literature. The Avrami constant, b, increases with decreasing austenitizing temperature, indicating a fast progress of transformation. Combining Pham¡¦s empirical growth model with Avrami equation, the CCT kinetics of C-Mn steels can be predicated well. The examination on the microstructural evolution during CCT suggests that the transformation of austenite to grain boundary allotriomorphs of ferrite (GBAF) can be divided into (1) nucleation and growth (NG) stage, (2) growth only (site saturation, SS) stage, and (3) coalescence stage. In the NG stage, the oblate ellipsoid aspect ratio of GBAF remains 3:1 until all the nucleation sites are exhausted., i.e. the onset of SS stage, then gradually decreases in the SS stage. Once the aspect ratio approaches unity, the coalescence starts to operate. Based on this observation, a physical base model is developed for predicting the austenite to GBAF CCT. This model possesses the capability to predict the start and finish transformation temperatures, the fraction transformed, and the final ferrite grain size. Although such model failed to predict the whole range of CCT curve due to the fact that only the GBAF transformation is included at present stage, it is still highly recommended for microstructural control. In order to completely predict the whole CCT curves, a semi-empirical physical base model is adopted. In addition, the methodology to predict multi-stage cooling transformation from CCT curves is also derived based on additivity rule and the concept of ideal TTT diagram. Associated with the additivity rule and the concept of ideal TTT diagram, such empirical model is validated to be applicable for the prediction of CCT and step wise cooling transformation. The latent heat is calculated using thermodynamic software for the accurate control of cooling history of the medium carbon steels which usually releases an abundance of latent heat. Associated with the semi-empirical transformation model, the calculation of latent heat is integrated into a heat transfer model and successfully implemented in a mill operation.

Many satellite applications require a model that represents a surface as it deforms over time. Yet, space applications demand a precise, low-weight, low-volume, and easy to implement solution. A metrology sensing system is presented in this thesis, consisting of a series of cameras and laser dot projectors positioned along the length of the antenna. This system accurately models the geometry of the surface to meet the demands of a space based radar. Each laser dot projector casts a matrix of points onto the antenna surface. The points are then imaged simultaneously by a pair of cameras, each having a different, but overlapping, viewpoint. Given the two overlapping images, a Gaussian nonlinear least squares algorithm solves the stereo-triangulation problem which provides the coordinates of the projected points and thereby maps the surface. There are three different strategies discussed in this thesis. The first strategy assumes the positions and orientations of the cameras are absolutely known. This produces an extremely accurate result; yet it is unrealistic to assume absolute knowledge of cameras locations and orientations for the application. The next strategy assumes the positions and orientations of the cameras are completely unknown in addition to the unknown surface. This program produces a less accurate, but more realistic, result considering the dynamic nature of rigid structures in space. To increase the accuracy and improve the robustness of these results, the third method employs a global metrology sensing system to reduce the uncertainty in the location and orientation of the outboard cameras relative to the center camera. This approach estimates the surface extremely accurately and, although more complex, offers advantages and addresses the desire for a family of designs wherein higher accuracy is achievable by further optimization.

<p> </p><p>The increasing demands for precision and efficiency in machining call for new control strategies for machining systems based on the identification of static and dynamic characteristics under operational conditions. By considering the machining system as a closed-loop system consisting of a machine tool structure and a machining process, the join system characteristics can be analyzed. The capability of a machining system is mainly determined by its static and dynamic stiffness.</p><p>The goal of this thesis is to introduce some concepts and methods regarding the identification of machining system stability. Two methods are discussed, one for the static behaviour analysis of a machine tool, and one for dynamic stability of a machining system. Preliminary results are indicating unambiguous identification of capabilities of machining systems static and dynamic characteristics.</p><p>The static behaviour of a machine tool is evaluated by use of a loaded double ball bar (LDBB) device. The device reproduces the real interaction between the join system, the machine tool elastic structure and the cutting process. This load is not equivalent to real cutting forces, but it does have a similar effect on the structure. This has been investigated both trough simulation and experimental work.</p><p>It is possible to capture the process – ­machine interaction in a machining system by use of the model-based identification approach. The identification approach takes into consideration this interaction and can therefore be used to characterize the machining system under operational conditions. The approach provides realistic prerequisites for in-process machining system testing. The model parameters can be further employed for control and optimization of the cutting process. Using different classification schemes, the model-based identification method is promising for the detection of instability.</p><p>Furthermore, it is the author’s belief that a model-based stability analysis approach is needed to exploit the full potential of a model driven parts manufacturing approach.</p>

The groups with which we associate influence our actions. This is often the case even when they are not deliberately organised but rather based on social categories, such as sex and skin colour, or cultural homogeneity, such as common language or customs. Group membership can cause widespread phenomena such as ingroup favouritism, polarisation of opinion and competition. Previous experiments have shown that these effects can be triggered by even completely arbitrary distinctions between groups. This thesis uses mathematical models to investigate under what circumstances these phenomena can arise. Using a game theoretical approach, the first three papers address the evolution of ingroup favouritism. Previous models have focused on the prisoners’ dilemma, interactions where the socially optimal behaviour is to co-operate, but where it is in the individual’s self-interest not to. The results presented here suggest that co-ordination problems may have been more important than those of co-operation in the evolution of an ingroup bias. In particular, this applies to common goals that require trust. It is also demonstrated in a behavioural experiment that such trust is most common within groups, but that it can emerge between groups through group reputation. The fourth paper focuses on a model on how cultural groups in contact can develop common norms, rather than polarise into different norm groups, by assuming a confirmation bias. The model is empirically tested on demographic and linguistic data from Mauritian Creole, a natural language developed from the mixing of parent languages. In the fifth paper, the group is defined by common preferences (e.g. for pop songs), which are transmitted in a random copying model. The competitive success of the groups, with respect to their size, is recorded on a toplist, the turnover rate of which is derived. In the final paper, people match up in pairs between groups according to their preferences, and all stable matchings are found under a specific assumption of bounded rationality, when people’s individual behaviour may be affected by the consequences for fellow group members.

Energy Benefit in Tidal Power Schemes' by Helen Suckling Abstract Predictions of energy output from a barrage in the Severn Estuary can be made by using a mathematical model describing the operation of the barrage linked to one of tidal flow. Estimates of the likely energy production from such a barrage have been made using a flat surface model of the estuary which incorporates real machinery operating characteristics. The flow through the barrage can be controlled optimally in order to obtain the greatest amount of energy from the tides. The energy predictions made by using the flat surface model are examined using a hydrodynamic model of flow in the estuary. A simple one-dimensional hydrodynamic model of the tidal flow in the Severn Estuary is presented. The area of the estuary under consideration is that which lies between approximately Berkeley in Gloucestershire and 11 fracombe on the North Devon coast. The only open boundary is assumed to be the seaward boundary. No account is taken of flow into the estuary from rivers. Finite amplitude shallow water wave equations, together with a representation of bottom friction, are used to describe the tidal behaviour in the estuary. The crosssectional topography of the estuary is assumed to be a rectangle. The boundary conditions are that there is no flow through the landward boundary and the water level at the seaward boundary is a known function of time. The equations are solved numerically as a system of ordinary differential equations. A simple Runge-Kutta method is used. The mqdel is used to obtain predictions of the level and time of high and low tide at certain points along the estuary. The results are compared with those obtained by using another, but more complex, onedimensional model. In the region of computation, the accuracy of the results of the two models are comparable. The effect of varying both the coefficient of friction and the form of the friction term is examined. The effect of linearizing the governing equations is also studied. A model of a tidal power barrage, sited between Weston-super-Mare and Cardiff, is then incorporated into the hydrodynamic model. The operation 'of the barrage is determined by using an open loop control, obtained by using a flat surface model of the estuary. The extent to which hydrodynamic effects may modify the energy predictions made by the flat surface are examined. variation of the time at which generation is allowed to start is found to affect the amount of energy predicted by the hydrodynamic model. The costate equations, which are necessary for the solution of the optimal control problem are derived, but the solution of these equations is not presented

In this thesis, I present, illustrate and empirically validate a novel approach to modelling and explaining design process. The main outcome of this work is the formal definition of the problem framing, and the formulation of a recursive model of framing in design. The model (code-named RFD), represents a formalisation of a grey area in the science of design, and sees the design process as a recursive interaction of problem framing and problem solving. The proposed approach is based upon a phenomenon introduced in cognitive science and known as (reflective) solution talkback. Previously, there were no formalisations of the knowledge interactions occurring within this complex reasoning operation. The recursive model is thus an attempt to express the existing knowledge in a formal and structured manner. In spite of rather abstract, knowledge level on which the model is defined, it is a firm step in the clarification of design process. The RFD model is applied to the knowledge-level description of the conducted experimental study that is annotated and analysed in the defined terminology. Eventually, several schemas implied by the model are identified, exemplified, and elaborated to reflect the empirical results. The model features the mutual interaction of predicates ‘specifies’ and ‘satisfies’. The first asserts that a certain set of explicit statements is sufficient for expressing relevant desired states the design is aiming to achieve. The validity of predicate ‘specifies’ might not be provable directly in any problem solving theory. A particular specification can be upheld or rejected only by drawing upon the validity of a complementary predicate ‘satisfies’ and the (un-)acceptability of the considered candidate solution (e.g. technological artefact, product). It is the role of the predicate ‘satisfies’ to find and derive such a candidate solution. The predicates ‘specifies’ and ‘satisfies’ are contextually bound and can be evaluated only within a particular conceptual frame. Thus, a solution to the design problem is sound and admissible with respect to an explicit commitment to a particular specification and design frame. The role of the predicate ‘acceptable’ is to compare the admissible solutions and frames against the ‘real’ design problem. As if it answered the question: “Is this solution really what I wanted/intended?” Furthermore, I propose a set of principled schemas on the conceptual (knowledge) level with an aim to make the interactive patterns of the design process explicit. These conceptual schemas are elicited from the rigorous experiments that utilised the structured and principled approach to recording the designer’s conceptual reasoning steps and decisions. They include • the refinement of an explicit problem specification within a conceptual frame; • the refinement of an explicit problem specification using a re-framed reference; and • the conceptual re-framing (i.e. the identification and articulation of new conceptual terms) Since the conceptual schemas reflect the sequence of the ‘typical’ decisions the designer may make during the design process, there is no single, symbol-level method for the implementation of these conceptual patterns. Thus, when one decides to follow the abstract patterns and schemas, this abstract model alone can foster a principled design on the knowledge level. It must be acknowledged that for the purpose of computer-based support, these abstract schemas need to be turned into operational models and consequently suitable methods. However, such operational perspective was beyond the time and resource constraints placed on this research.

Controlled Start Transmissions (CST) can be described as a mechanical transmission combined with a wet clutch for controlled torque output. CST:s are commonly used to start up heavy loads for example mining conveyors. Several CST:s can work together to share the load. The transferred torque is controlled by a hydraulic wet clutch which is a proven technology for high torque transfer and low wear. This thesis is a part of a project to increase the knowledge and improve the CST design and control performance. The heat generation in the wet clutch is the focus of this thesis. Literature review shows that most research is done in order to get high accuracy for smaller clutches and most of the high torque engagements have very short transients.Models for the CST clutch heat generation together with thermal behavior have been developed and investigated. This includes a temperature model together with a kinetic model of the gearbox and a clutch torque model. Validation of separate model components and sensitivity analysis of the parameters are made. The developed model is then analyzed by comparing measurements from a commission site and simulations to get an idea of how much heat is generated.