Satellite data have shown that east-west oriented cloud bands, known as Intertropical convergence zone (ITCZ), propagate eastwards along the equator throughout the year and northwards during boreal summer on intraseasonal time scales. The northward propagations over Bay of Bengal have important connection with onset of south Asian monsoon and active-break cycles of the Indian monsoon. Some studies on mean structure of ITCZ have concluded that preferred location of ITCZ is governed by meridional variation of sea surface temperature (SST) while other studies have stressed the importance of heating in the free atmosphere. Studies on the migration of ITCZ have shown that northward migration of maximum convergence zone is due to generation of positive barotropic vorticity north of the convection in the boundary layer due to internal dynamics of the atmosphere. In the present study mean and transient structure of northward migration of ITCZ over Bay of Bengal is simulated with the help of a general circulation model (GCM). The mean ITCZ is found not to occur at SST maximum or SST gradient maxima. A new simple model for the mean state of ITCZ based on moisture budget, linear friction and hydrostatic assumption is proposed. It highlights the relative importance of SST and atmospheric effects in generation of maximum convergence. The large cancellation between the effect of SST on boundary layer and thermodynamic effects in free troposphere is shown to control convergence. The model also shows that latitude and time independent linear friction parameterization in a simple model is able to predict monthly mean location of ITCZ in a GCM. The results give a quantitative understanding about the relative role of surface effects and atmospheric effects in determining location of the mean ITCZ. A simple linear model for understanding the mechanism of instability that governs the northward migration of ITCZ is proposed. Vertical shear in mean winds couples the barotrpic and baroclinic modes in free troposphere in this model. The model is able to predict the correct scale with standard values of friction and diffusion parameters. The mechanism of instability is found to be due to internal dynamics of troposphere. It is shown that direction of propagation is decided by vertical shear in zonal as well as meridional mean winds. This is contrary to the previous studies which conclude that either vertical shear in zonal winds or vertical shear in meridional winds control the direction of propagation.

This document is a report summering the master thesis work dealing with the Computational Fluid Dynamic (CFD) study of the flow around a high-speed train. The model is a scaled 1:50 generic train with two cars, one inter-car gap and simplified bogies. A platform is set on the side of the train since one of the aim of the study is to look at the consequences of the phenomena in the wake on people or objects standing on the platform. The slipstream is one of this phenomena, it is due to the fact that the viscous air is dragged when the train is passing. If too strong, it can move or destabilize people or objects on the platform. In addition of the slipstream study, a velocity profile study, a drag and lift coefficients analyze as well as a Q-factor study and a frequency study have been realized. Some results of these different studies are compared with the ones obtained on the same model with a Delayed Detached Eddy Simulation (DDES). Since the flow is turbulent, for those different studies, the flow has been simulated with a Reynolds Averaged Navier-Stokes equation model (RANS) which is the k-ω SST model for the turbulence. The study of the slipstream allowed to calculate the Technical Specification for Interoperability (TSI) which must not be higher that the European Union requirement set at 15.5 m/s, the result obtained is 8.1 m/s which is then lower than the limit. The velocity profile shows similarities with the DDES results even though it is less detailed. The same conclusion is done for the Q-plot where is clearly visible the two counter-rotating vortices in the wake. Finally, a Fast Fourier Transform algorithm has been applied to instantaneous velocity results in the wake of the train in order to get the frequency of the aerodynamic phenomena in that wake. The main frequency is 25 Hz and corresponds to a Strouhal number of 0.1, quite closed to the results obtained with DDES which is 0.085. The results of the RANS and DDES are reasonably similar and by regarding at the large difference between the cell numbers (respectively 8 500 000 and 20 000 000) it can be conclude that in some ways the RANS model can be preferred at the DDES to save time for the computation but it does not contain the small scales resolved by the DDES.

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This study examines the efficacy of Sentinel-1 Radial Velocity (RVL) imagery at determining the position of ocean current front features, using the Gulf Stream (GS) and Agulhas Current (AC) as case studies. Fronts derived from RVL imagery are compared to fronts derived from Sea Surface Temperature (SST) imagery, specifically Multi-scale Ultra-high Resolution Sea Surface Temperature Analysis (MURSST) data. In the case of the GS, front locations from the Naval Oceanographic Office (NAVOCEANO) were also used for comparison. Only the northern walls of ocean current features are considered in this study, which is broken into three main steps: Preprocessing, front extraction, and front comparison. First, RVL imagery is selected from Sentinel-1 ocean products, preprocessed to remove antenna mispointing artifacts, and all products from the same orbit are combined into a single swath. Second, front features are extracted from both the RVL and MURSST imagery using a ridge detection algorithm, the main ocean current is chosen from all ridge features using a ranking algorithm, and the northern wall of this current is extracted. Third, the RVL, SST, and in the case of the GS, NAVOCEANO GS locations, features are compared using a symmetric Hausdorff Distance (HD) measure, and Mean Hausdorff Distance (MHD). In some cases, the automatic front extraction failed by either misclassifying an eddy or similar ocean feature as the ocean current in either the RVL or SST image or failed to extract the entire length of the front visible within the image. All the SST and RVL fronts were classified manually to determine the success rate of the automatic front extraction and to exclude failed front extractions from the analysis, as they are not accurate representations of the SST and RVL data’s ability to detect fronts. In special cases, the RVL image itself does not detect the entire ocean current, such that there are noticeable gaps in the ocean current. Similarly, in special cases the MURSST does not detect the entire ocean current. The automatic front extraction succeeded 65% of the time, including the special cases. The results demonstrated that RVL products were effective at determining the location of ocean fronts where the angle of the front's normal vector is within approximately 40° of the sensor’s azimuthal heading. A mean HD of 31.9 km and a mean MHD of 13.2 km was calculated for all front pairs over all study areas. The RVL fronts appeared consistently to the north of the SST fronts, with an average offset of 25.4 km between the centroids of the SST and RVL fronts. Positive correlations were noted between cloud coverage and MURSST error in both study regions. Several RVL images detected ocean currents in regions of high MURSST error where the MURSST did not detect the ocean currents, suggesting that RVL may provide more accuracy than SST-based products in clouded regions where there is no auxiliary data.

Traditional retail with personal service is becoming scarce. The personal interaction is replaced with self service alternatives, and the consumer is now seen as a co-service producer. What is the general attitude towards the service provided within these automated experiences? Is the automated experience of service comparable to the traditional service that is expected from the customer, or is the industry moving too fast, risking the exclusion of certain consumer groups in the quest for automation? This study conducted semi-structured interviews with a broad range of consumers and used thematic analysis in an effort to discover consumers' unique motivations in regards to self service alternatives in physical stores. The result showed that most consumers are satisfied as long as the service works as intended. But when problems arise, many of the respondents point out the lack of standardization, human support, long waiting times, and control within the user interface. Findings in this study contribute to the industry by identifying traits within the technology viewed by the consumer as enablers or disablers.

Since the introduction of Toyota's Production System, the deployment of lean production systems (or lean manufacturing), and more advanced technological developments, Participatory Management Practices (PMP) have been viewed as lying at the heart of successful manufacturing workplaces. Studies on technology and PMP have concluded that the state of technology in a company unequivocally shapes PMP and can open spaces to enhance the wellbeing of workers regardless of the PMP dynamics. However, these claims are contested by studies that question the positive effects from PMP. These studies argue that workplaces are organized in such a way that workers are viewed as mere resources to be deployed in the production process, without paying attention to their human morale and agency. This research presents a case study of a food plastics packaging firm that contextualizes, describes, and analyzes: 1) PMP from a Socio-technical Systems Theory (SST) perspective to further our understanding of the role of participative dynamics in the wellbeing of workers; and 2) the dynamics of control-resistance in the workplace as a measure of dignity at work in the context of power relations. This research provides a rich exploration of a workplace that is facing and managing the challenge of automation and technological development. Using an extended case study research method (Burawoy, 2009), data are collected by observing workers' daily interactions with a combination of technologies. These observations reveal the importance of team dynamics in the production process. The observed PMP dynamics show conflictive, competitive, and cooperative behaviors that are negotiated through continuous human-machine, machine-machine, and human-human interactions in the production process. However, management is found to be indifferent to the impact that a combination of technologies and lean production approaches have on participation dynamics. This indifference inhibits managers from embracing and appreciating the value of PMP. All the identified expressions of what technology and PMP mean to workers, and their dynamics, show an ongoing negotiating process. This process comes from all types of participation in which a worker struggles for dignity. The organizational structure of the firm expects workers to display specific types of participation in team efforts, but workers are also provided with opportunities to negotiate their interests or struggle for dignity by changing their type of participation in team activities. The work processes and findings described in this dissertation generally support the theory of Hodson (2001). Further, this research develops the concept of "combination of technologies," which can be used to help observe workers' understanding of technology and participative dynamics. The research also identifies various types of participation based on the interactions of workers in the technology process and how workers manage or safeguard their dignity based on their engagement with different types of participation in team-based situations or events. Finally, this research identified how participative engagement by workers can be used as a power mechanism to retain their dignity. / Doctor of Philosophy / Modern manufacturing production is based on the increasing use of technology and workers' participation in problem solving when it comes to the production system. These types of production systems are called Lean Production Systems. These systems stem from the philosophy of doing more with less and are viewed as lying at the heart of successful manufacturing workplaces. However, studies on technology and teams have concluded that not only does technology shape the dynamics of teams, but the practices and dynamics of workers in teams can open spaces to enhance human wellbeing. Even so, some studies question the positive effects of worker participation in teams based on Participatory Management Practices (PMP). These studies argue that workplaces are organized in such a way that workers are viewed as mere resources to be deployed in the production process, without paying attention to human morale and agency. This research is a case study of a rigid food plastics packaging firm that contextualizes, describes, and analyzes: (1) the participation of workers in PMP from the perspective that workers and technology have a social relationship with deep contextual meaning; and (2) a measure of human dignity in the context of power relations and how control and resistance are met in these spaces. This research provides a rich exploration of a workplace that is facing and managing the challenge of automation and technological development. Using an extended case study research method (Bloomfield, 1994 as cited in Burawoy, 2009, p. 154), data are collected from workers' daily interactions with a combination of technologies. The importance of how people participate in teams during the production process, was observed and acknowledged to enhance workers wellbeing. A range of dynamics were observed and defined as conflictive, competitive, or cooperative behavior that are negotiated through the continuous human-machine, machine-machine, and human-human interactions that occur during the production process. However, management is indifferent to and disregards the impact that technology has on worker participation in teams and is unconcerned with contrasting meanings of technology from workers, which means they are not paying attention to how these factors impact the use of technology and participation dynamics. All expressions of what technology and worker participation means show an ongoing negotiating process in which workers struggle for dignity. This research follows Hodson (2001) categories of struggle for dignity as a measure of self-worth. This research develops concepts that can be used to help observe workers' understanding of technology and participative dynamics, as well as identifies different types of participation by observing the interactions of workers in the technology process. This research identified how workers manage or safeguard their dignity based on their engagement with different types of participation observed during team-based situations or events. Finally, the research identified how workers' ability to change their interactions in teams is used as a power mechanism to retain their dignity.

Ces travaux de recherche ont pour but d’évaluer la méthode dite de la "Simulation auxEchelles Adaptées" (SAS pour Scale-Adaptive Simulation). Cette approche coïncide avec uneapproche RANS classique dans les zones pariétales attachées et adapte le niveau de viscositéturbulente dans les zones décollées pour y permettre une résolution partielle des structures turbulentes.Dans une première partie, une analyse théorique du modèle SAS original a été menéeet a permis de développer une correction visant à favoriser l’adaptation du niveau de viscositéturbulente dans les zones sièges d’instabilités de type Kelvin-Helmholtz. Le modèle ainsi corrigéest nommé SAS-αL. Les modèles SAS et SAS-αL ont été implantés dans le code de calculNavier-Stokes elsA de l’ONERA. À l’issue de cette étape, trois cas académiques d’écoulementsturbulents instationnaires, cylindre à grand nombre de Reynolds, marche descendante et cavitétranssonique, ont été simulés grâce aux trois modèles de turbulence SST, SAS et SAS-αL. Outreune comparaison aux bases de données expérimentales disponibles, une attention particulièrea été portée à l’influence de paramètres numériques tels que des schémas numériques d’ordreélevé. Enfin, afin d’étudier la viabilité de l’approche SAS dans un contexte industriel, les troismodèles de turbulence ont été testés sur une configuration issue de l’industrie aéronautique etcorrespondant à la sortie d’air chaud d’un système de dégivrage des nacelles d’avion. La comparaisondes prévisions obtenues avec les modèles SST, SAS et SAS-αL aux données expérimentalesobtenues à l’ONERA a permis de montrer un gain de précision grâce à l’emploi de l’approcheSAS et ce pour un coût de calcul compatible avec un cycle de conception industrielle. / This research work is meant to assess an upgraded URANS approach, namely the Scale-Adaptive Simulation (SAS). This method is similar to a conventional RANS approach (namelythe SSTmodel) in attached areas and is able to adapt the eddy-viscosity level in detached areas toensure the resolution, at least partially, of the turbulent structures. In a first part of this researchwork, an improvement of the SAS approach is suggestedto allowa better sensitivity of themodelto instabilities such as Kelvin-Helmholtz ones. This "improved" model is referred to as SAS-αLmodel. Both SAS and SAS-αL models were implemented in the ONERA Navier-Stokes solverelsA and both of themaswell as the SSTmodelwere tested on academic test cases : a cylinder in acrossflowat a high Reynolds number, a backward-facing step flowcorresponding to theDriver&Seegmiller experiment and the transonic flow over the M219 cavity experimentally investigatedby de Henshaw. The influence of the numerical parameters was deeply investigated and particularattention was paid to the high-order space-discretization schemes effects. The reliabilityof the SAS approach in an industrial framework was assessed on an aeronautic configurationnamely a nacelle de-icing device. Comparisons between the threemodels (SST, SAS and SAS-αL)and an experimental database available at ONERA - The French Aerospace Lab have shown thebetter accuracy of the SAS approach as well as the high potential of the SAS-αL model.

Syftet med studien har varit att undersöka hur telekomkunder användning av själv-serviceteknologi (SST) kan öka. Relevant litteratur som SST, teknologisk acceptans, user experience (UX), customer experience (CX) och servicedesign (SD) har identifierats och förankrat studien vetenskapligt. Baserat på syftet och den teoretiska grunden har en designstrategi skapats för att undersöka detta på ett relevant sätt på ett telekomföretag i Sverige. Studien har utgått från en formativ utvärdering där expertanvändares upplevelser av telekomkunder, kundservice och själv-serviceteknologi har studerats, för att kunna identifiera möjliga problem och förbättringsområden. Semi-strukturerade djupintervjuer har använts som datainsamlingsmetoden på grund av de förutsättningar som fanns för studien. Detta har i kombination med analysstrategierna har medverkat till identifieringen av kontextuella fynd som kan öka användning av SST för telekomföretagets kunder. Några av dessa fynd är att SST behöver vara standardiserad inom telekombranschen och att telekomföretaget kan öka användandet genom att informera sina kunder mer om möjligheterna med SST. I Studien har också faktorer som tyder på ett samband mellan områdena service, SST och telekomkunder identifierats, detta kan öka förståelsen för hur SST i denna kontext bör utvecklas och designas framöver.