Friction stir welding has become a popular forging technique used in many applications. The Swedish Nuclear Fuel and Waste Management Company (SKB) evaluates this method to seal the 5 cm thick copper canisters that will contain the spent nuclear fuel. To produce repetitive, high quality welds, the process must be controlled, and today a cascade controller is used to keep the desired stir zone temperature. In this thesis, the control system is extended to also include a plunge depth controller. Two different approaches are evaluated; the first attempt is a decentralized solution where the cascaded temperature controller is kept, and the second approach uses a non-linear model predictive controller for both depth and temperature. Suitable models have been derived and used to design the controllers; a simpler model for the decentralized control and a more extensive, full model used in the non-linear model predictive controller that relates all the important process variables. The two controller designs are compared according to important performance measures, and the achieved increase in performance with the more complex non-linear model predictive controller is evaluated. The non-linear model predictive controller has not been implemented on the real process. Hence, simulations of the closed loop systems using the full model have been used to compare and evaluate the control strategies. The decentralized controller has been implemented on the real system. Two welds have been made using plunge depth control with excellent experimental results, confirming that the decentralized controller design proposed in this thesis can be successfully used. Even though the controller manages to regulate the plunge depth with satisfying performance, simulations indicate that the non-linear model predictive controller achieves even better closed loop performance. This controller manages to compensate for the cross-connections between the process variables, and the resulting closed loop system is almost decoupled. Further research will reveal which control design that will finally be used. / ''Friction stir welding'' har blivit en populär svetsmetod inom många olika tillämpningar. På Svensk Kärnbränslehantering AB (SKB) undersöks möjligheten att använda metoden för att försegla de 5 cm tjocka kopparkapslarna som kommer innehålla det använda kärnbränslet. För att kunna producera repeterbara svetsar utav hög kvalité krävs det att processen regleras. Idag löses detta med en temperaturregulator som reglerar svetszonens temperatur. I detta examensarbete utökas styrsystemet med en regulator för svetsdjupet. Två olika lösningar har utvärderats; först en decentraliserad lösning där temperatur-regulatorn behålls och sedan en lösning med en olinjär modellprediktiv reglering (MPC) som reglerar både djup och temperatur. Passande modeller har tagits fram och har använts för att designa regulatorerna; en enklare modell för den decentraliserade regulatorn och en utökad, komplett modell som används i den olinjära MPC:n och som beskriver alla viktiga variabler i processen. Viktiga prestandamått har jämförts för de båda regulatorstrukturerna och även prestandaökningen med den olinjära MPC:n har utvärderats. Då denna regulator inte har implementerats på den verkliga processen har simuleringar av den kompletta modellen använts för att jämföra och utvärdera regulatorstrukturerna. Den decentraliserade regulatorn har implementerats och testats på processen. Två svetsar har gjorts och de har givit utmärkta resultat, vilket visar att regulatorstrukturen som presenteras i rapporten fungerar bra för reglering av svetsdjupet. Trots att den implementerade regulatorn klarar av att reglera svetsdjupet med godkänt resultat, så visar simuleringar att den olinjära MPC:n ger ännu bättre reglerprestanda. Denna regulator kompenserar för korskopplingar i systemet och resulterar i ett slutet system som är nästan helt frikopplat. Ytterligare forskning kommer avgöra vilken av strategierna som kommer att användas i slutprodukten.

Die vorliegende Arbeit leistet einen Beitrag zur Identifizierung von Einflussgrößen und Fehlerursachen auf Verkehrsunfälle. Diese können als Grundlage für Hinweise für den Einsatz und die Gestaltung von Fahrerassistenzsystemen genutzt werden. Dafür wurden insgesamt 506 Unfälle umfassend (in depth) untersucht. Zur Analyse der Pre-Crash-Phase der Unfälle wurden die Ergebnisse einer psychologischen Befragung mit Angaben aus der polizeilichen Verkehrsunfallanzeige, Informationen zur Unfallstelle, medizinischen Berichten sowie Informationen aus der technischen Rekonstruktion integriert. Anschließend wurde eine Fehleranalyse unter Betrachtung der Teilsysteme Fahrer, Umwelt und Fahrzeug durchgeführt. Um den bestmöglichen Befragungszeitpunkt herauszufinden, wurden in einer Vorstudie jeweils 15 Interviews am Unfallort sowie telefonische Interviews ein bis 14 Tage bzw. 15 bis 90 Tage nach dem Unfall bezüglich der Anzahl ihrer Genauigkeits- und Glaubhaftigkeitsmerkmale, der Motivation zur Interviewteilnahme sowie möglicher Vergessenseffekte verglichen. Im Ergebnis konnten keine Nachteile nachträglicher telefonischer Befragungen im Vergleich zu Befragungen an der Unfallstelle gefunden werden. Zur Fehleranalyse wurde ein verkehrspsychologisches Fehlerklassifikationsschema auf der Basis der verhütungsbezogenen Klassifikation von Fehlhandlungsursachen (Hacker, 1998) erstellt. Mit dessen Hilfe wurden insgesamt 696 Unfalleinflussfaktoren für die Unfallverursacher (n=343) ermittelt. Im Ergebnis wurde so bei allen Unfalltypengruppen ein hoher Anteil von Fehlern infolge von Ablenkung sowie Aktivierungsmängeln festgestellt (jeweils zwischen 28 % und 47%). Des Weiteren gab es bei Kreuzungsunfällen zahlreiche Fehler infolge von Sichtverdeckungen (40%), Fokusfehlern (30%), Reizmaskierungen (26%) und Verstößen gen die Verkehrsregeln (11%). Unfälle durch Abkommen von der Fahrbahn traten zudem häufig infolge von Erwartungsfehlern (35%), Reizmaskierungen (26%), Verstößen gegen die Verkehrsregeln (24%) sowie Zielsetzungs- bzw. Handlungsfehler (23%) auf. Unfälle im Längsverkehr passierten des Weiteren durch Erwartungsfehler (36%), Zielsetzungs- und Handlungsfehler (36%) sowie durch Setzen eines falschen Aufmerksamkeitsfokus (24%) auf. Anhand dieser Studienergebnisse ist das Sicherheitspotential für Fahrerassistenzsysteme, welche den Fahrer bei der Informationsaufnahme unterstützen und ihm helfen Ablenkungen und Aktivierungsdefizite zu vermeiden, als hoch einzuschätzen. So könnten insgesamt über zwei Drittel der erfassten Fehlhandlungen vermieden werden. Darüber hinaus münden die Studienergebnisse in ein Klassifikationsschema zur Erfassung von Unfalleinflussfaktoren, welches im Rahmen der Unfallforschung dauerhaft eingesetzt werden sollte.

The flow characteristics of the subcritical and supercritical flows over a free overfall in a rectangular channel are studied experimentally. A series of experiments were conducted in a tilting flume with a wide range of flow rate. Data collected by several researchers are also included. An empirical relationship, which gives the flow rate as a function of the brink depth, the channel bed slope and the bed roughness are confirmed by using data collected in present study. In addition, the behaviors of the ratio of the brink depth to the critical depth according to several flow parameters are examined. Further, the location of the critical depth in subcritical flows while flow is approaching to the fall is investigated. It is concluded that the location of the critical depth in subcritical flow is a function of the Froude number, channel bed slope and the Manning roughness coefficient. The resemblance or the difference in the occurrence of the profile in sub and supercritical flows examined.

Statistical data depth is a nonparametric tool applicable to multivariate datasets in an attempt to generalize quantiles to complex data such as random vectors, random functions, or distributions on manifolds and graphs. The main idea is, for a general multivariate space M, to assign to a point x ∈ M and a probability distribution P on M a number D(x; P) ∈ [0, 1] characterizing how "centrally located" x is with respect to P. A point maximizing D(·; P) is then a generalization of the median to M-valued data, and the locus of points whose depth value is greater than a certain threshold constitutes the inner depth-quantile region corresponding to P. In this work, we focus on data depth designed for infinite-dimensional spaces M and functional data. Initially, a review of depth functionals available in the literature is given. The emphasis of the exposition is put on the unification of these diverse concepts from the theoretical point of view. It is shown that most of the established depths fall into the general framework of projection-driven functionals of either integrated, or infimal type. Based on the proposed methodology, characteristics and theoretical properties of all these depths can be evaluated simultaneously. The first part of the work is devoted to the investigation of these theoretical properties,...

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Yes / The flow in the main channel of a meandering compound channel does not occur in the ridge direction because of the effect of the upstream floodplain flows. This study proposes a model for estimating the flow direction in the depth-averaged two-dimensional domain (depth-averaged flow angles) between the entrance and the apex sections. Detailed velocity measurements were performed in the region between the meander entrance section and apex section in a large-scale meandering compound channel. The vertical size of the secondary current cell is highly related to the depth-averaged flow angle; thus, the means of the local flow angles above the secondary current cell and within the cell are separately discussed. The experimental measurements indicate that the mean local flow angle above the cell is equal to the section angle, whereas the mean local flow angle within the cell is equal to zero. The proposed model is validated using published data from five sources. Good agreement is obtained between the predictions and measurements, indicating that the proposed model can accurately estimate the depth-averaged flow direction in the meandering compound channels. Finally, the limitations and application ranges of the model are discussed. / National Key Research and Development Program of China (No. 2016YFC0402302), the National Natural Science Foundation of China (Nos. 51539007 and 51609160)

Background: Relational depth (RD) is gaining empirical attention as a well-articulated phenomenon within therapeutic relationship literature. Despite this, with the exception of a small number of client-focused studies, research of this issue is relatively sparse and predominantly reflects upon therapeutic work from a person-centred orientation. Aims and Methods: The aim of this research was to explore clients’ experiences of RD within individual Cognitive Behavioural Therapy. Eight clients, who had self-identified at least one helpful relational moment with their therapist, were interviewed about their experience. The interviews were transcribed and analysed employing Grounded Theory methods. Findings and Discussion: Four core categories emerged from the analysis. These were: (1) the experience of the therapist, (2) the experience of self, (3) the experience of the therapy relationship, and (4) the perceived impact/effects of the moment of RD. Each core category and the corresponding subordinate codes are described by illustrative quotes from the participants. Following this, each finding is discussed in relation to RD research and beyond. Conclusions: This research project ultimately demonstrates that clients who have worked with a cognitive behavioural therapist can and do experience RD during their individual therapy. The like-by-like comparison of the findings with previous RD research indicated a high degree of convergence. Nevertheless, when differences are present, clients’ RD experience is influenced and to some extent contained by dissimilarity in experience between therapist and non-therapist clients. This is also manifested through theoretical differences of the given therapeutic approach. No negative impact or effect was described by the clients as a result of their experience of a moment of RD. The implications of the findings are highlighted and future research is suggested.

In our society with its aging population, the design and implementation of a highperformance distributed multi-sensor and information system for autonomous physical services become more and more important. In line with this, this thesis proposes an Intelligent Multi-Sensor System, IMSS, that surveys a human activities space to detect and identify a target for a specific service. The subject of this thesis covers three main aspects related to the set-up of an IMSS: an improved depth measurement and reconstruction method and its related uncertainty, a surveillance and tracking algorithm and finally a way to validate and evaluate the proposed methods and algorithms. The thesis discusses how a model of the depth spatial quantisation uncertainty can be implemented to optimize the configuration of a sensor system to capture information of the target objects and their environment with required specifications. The thesis introduces the dithering algorithm which significantly reduces the depth reconstruction uncertainty. Furthermore, the dithering algorithm is implemented on a sensor-shifted stereo camera, thus simplifying depth reconstruction without compromising the common stereo field of view. To track multiple targets continuously, the Gaussian Mixture Probability Hypothesis Density, GM-PHD, algorithm is implemented with the help of vision and Radio Frequency Identification, RFID, technologies. The performance of the tracking algorithm in a vision system is evaluated by a circular motion test signal. The thesis introduces constraints to the target space, the stereo pair characteristics and the depth reconstruction accuracy to optimize the vision system and to control the performance of surveillance and 3D reconstruction through integer linear programming. The human being within the activity space is modelled as a tetrahedron, and a field of view in spherical coordinates are used in the control algorithms. In order to integrate human behaviour and perception into a technical system, the proposed adaptive measurement method makes use of the Fuzzily Defined Variable, FDV. The FDV approach enables an estimation of the quality index based on qualitative and quantitative factors for image quality evaluation using a neural network. The thesis consists of two parts, where Part I gives an overview of the applied theory and research methods used, and Part II comprises the eight papers included in the thesis.

Three Dimensional Video (3DV) has become increasingly popular with the success of 3D cinema. Moreover, emerging display technology offers an immersive experience to the viewer without the necessity of any visual aids such as 3D glasses. 3DV applications, Three Dimensional Television (3DTV) and Free Viewpoint Television (FTV) are auspicious technologies for living room environments by providing immersive experience and look around facilities. In order to provide such an experience, these technologies require a number of camera views captured from different viewpoints. However, the capture and transmission of the required number of views is not a feasible solution, and thus view rendering is employed as an efficient solution to produce the necessary number of views. Depth-image-based rendering (DIBR) is a commonly used rendering method. Although DIBR is a simple approach that can produce the desired number of views, inherent artifacts are major issues in the view rendering. Despite much effort to tackle the rendering artifacts over the years, rendered views still contain visible artifacts. This dissertation addresses three problems in order to improve 3DV quality: 1) How to improve the rendered view quality using a direct approach without dealing each artifact specifically. 2) How to handle disocclusions (a.k.a. holes) in the rendered views in a visually plausible manner using inpainting. 3) How to reduce spatial inconsistencies in the rendered view. The first problem is tackled by an edge-aided rendering method that uses a direct approach with one-dimensional interpolation, which is applicable when the virtual camera distance is small. The second problem is addressed by using a depth-based inpainting method in the virtual view, which reconstructs the missing texture with background data at the disocclusions. The third problem is undertaken by a rendering method that firstly inpaint occlusions as a layered depth image (LDI) in the original view, and then renders a spatially consistent virtual view. Objective assessments of proposed methods show improvements over the state-of-the-art rendering methods. Visual inspection shows slight improvements for intermediate views rendered from multiview videos-plus-depth, and the proposed methods outperforms other view rendering methods in the case of rendering from single view video-plus-depth. Results confirm that the proposed methods are capable of reducing rendering artifacts and producing spatially consistent virtual views. In conclusion, the view rendering methods proposed in this dissertation can support the production of high quality virtual views based on a limited number of input views. When used to create a multi-scopic presentation, the outcome of this dissertation can benefit 3DV technologies to improve the immersive experience.

Dado un conjunto de datos, o una distribución, en un espacio de dimensión mayor a uno, las proyecciones aleatorias consisten en proyectar los datos, o calcular la marginal de la distribución, en un subespacio de menor dimensión que ha sido elegido de forma aleatoria. En nuestro caso de dimensión uno. En esta tesis presentamos dos aplicaciones de las proyecciones aleatorias. La primera es una definición de profundidad, que es computacionalmente efectiva, aproxima a la conocida profundidad de Tukey y es válida tanto en espacios multidimensionales como funcionales. La segunda es un test de Gaussianidad para procesos estrictamente estacionarios, que rechaza procesos no Gaussianos con marginal unidimensional Gaussiana. / A random projection consists in projecting a given data set, or in computing the marginal of a distribution, on a randomly chosen lower dimensional subspace. In our case, it is of dimension one.In this thesis, we present two applications of the random projections. The first one is a new definition of depth that is computationally effective, approximates the well-known Tukey depth and works as much in multidimensional spaces as in functional. The second is a test of Gaussianity for strictly stationary processes, which rejects non-Gaussian processes with Gaussian one-dimensional marginal.