Many theories of physics beyond the Standard Model predict the existence of TeV-scale resonances that decay to top quark pairs. This thesis presents a search for such resonances produced in proton-proton collisions at a centre-of-mass energy of 7 TeV at the CERN Large Hadron Collider with 4.7 fb−1 of data collected by the ATLAS detector in 2011. The search is performed in the channel where both top quarks decay hadronically and emerge in highly boosted states, and the collimated decay products of each boosted top quark are reconstructed as a single large jet (a “top quark jet”). A tagging technique based on the distinctive masses and substructures of these top quark jets is used to distinguish them from light quark and gluon jets. The data are found to be consistent with Standard Model predictions, and 95% credibility level upper limits are set on the cross section times branching ratio for leptophobic Z' bosons in a Topcolour model and Kaluza-Klein gluons as predicted by the bulk Randall-Sundrum model. These limits exclude Kaluza-Klein gluons with masses between 1.02 TeV and 1.62 TeV. The substructure of light quark and gluon jets, which form the dominant background to hadronically decaying boosted top quarks, is studied in an auxiliary measurement using 35 pb−1 of data collected by ATLAS during the 2010 run period. The observed substructure of these jets are found to be in good agreement with theoretical predictions.

Many theories of physics beyond the Standard Model predict the existence of TeV-scale resonances that decay to top quark pairs. This thesis presents a search for such resonances produced in proton-proton collisions at a centre-of-mass energy of 7 TeV at the CERN Large Hadron Collider with 4.7 fb−1 of data collected by the ATLAS detector in 2011. The search is performed in the channel where both top quarks decay hadronically and emerge in highly boosted states, and the collimated decay products of each boosted top quark are reconstructed as a single large jet (a “top quark jet”). A tagging technique based on the distinctive masses and substructures of these top quark jets is used to distinguish them from light quark and gluon jets. The data are found to be consistent with Standard Model predictions, and 95% credibility level upper limits are set on the cross section times branching ratio for leptophobic Z' bosons in a Topcolour model and Kaluza-Klein gluons as predicted by the bulk Randall-Sundrum model. These limits exclude Kaluza-Klein gluons with masses between 1.02 TeV and 1.62 TeV. The substructure of light quark and gluon jets, which form the dominant background to hadronically decaying boosted top quarks, is studied in an auxiliary measurement using 35 pb−1 of data collected by ATLAS during the 2010 run period. The observed substructure of these jets are found to be in good agreement with theoretical predictions.

De nos jours, nous assistons à l'émigration du Web de données vers le Web orienté services. L'amélioration des capacités et fonctionnalités des moteurs actuels de recherche sur le Web, par des techniques efficaces de recherche et de sélection de services, devient de plus en plus importante. Dans cette thèse, dans un premier temps, nous proposons un cadre de composition de services Web en tenant compte des préférences utilisateurs. Le modèle fondé sur la théorie des ensembles flous est utilisé pour représenter les préférences. L'approche proposée est basée sur une version étendue du principe d'optimalité de Pareto. Ainsi, la notion des top-k compositions est introduite pour répondre à des requêtes utilisateurs de nature complexe. Afin d'améliorer la qualité de l'ensemble des compositions retournées, un second filtre est appliqué à cet ensemble en utilisant le critère de diversité. Dans un second temps, nous avons considéré le problème de la sélection des services Web en présence de préférences émanant de plusieurs utilisateurs. Une nouvelle variante, appelée Skyline de services à majorité, du Skyline de services traditionnel est défini. Ce qui permet aux utilisateurs de prendre une décision " démocratique " conduisant aux services les plus appropriés. Un autre type de Skyline de services est également discuté dans cette thèse. Il s'agit d'un Skyline de Services de nature graduelle et se fonde sur une relation de dominance floue. Comme résultat, les services Web présentant un meilleur compromis entre les paramètres QoS sont retenus, alors que les services Web ayant un mauvais compromis entre les QoS sont exclus. Finalement, nous avons aussi absorbé le cas où les QoS décrivant les services Web sont entachés d'incertitude. La théorie des possibilités est utilisée comme modèle de l'incertain. Ainsi, un Skyline de Services possibilité est proposé pour permettre à l'utilisateur de sélectionner les services Web désirés en présence de QoS incertains. De riches expérimentations ont été conduites afin d'évaluer et de valider toutes les approches proposées dans cette thèse.

Organic semiconductors are very attractive for thin film Organic Photodetectors (OPDs) since they possess a number of desirable attributes for optical sensing including high absorption coefficients over visible and ultraviolet wavelengths and compatibility with large-area deposition processes such as ink-jet, screen printing, and solution processing. OPDs, in general, utilize a vertical device architecture where the photoactive organic semiconductor layers are sandwiched between top and bottom electrodes that provide electrical contact. More recently, an interest in utilizing a lateral device architecture instead of the vertical one, has emerged. In this architecture, the two contacts are positioned on the two sides of the photoactive material with respect to the direction of the incoming signal, separated by a small gap. However, the factors governing lateral OPDs’ photo-response are still not well understood. In this thesis, we fabricate top-contact lateral OPDs using a thermal evaporation only fabrication process. We study the factors governing both the dark and photo currents of lateral OPDs. The effect of the wide gap between the two electrodes on the current-voltage characteristics is discussed and the role of space charge limited conduction is investigated. The contributions in the photoresponse of light scattering through the active layers as well as the back reflection of light at the metallic contacts are emphasized. The reproducibility over repeated operation cycles of both dark and photo currents values is explored. Exposure to light of the lateral OPD is found to lead to a significant increase in the dark current. The role of the conductivity enhancement in the channel due to light-induced trap filling is investigated. External quantum efficiency and detectivity estimates are given for deep ultraviolet lateral (DUV) OPDs. A comparison with vertical DUV OPDs performances is provided. Finally, the use of a phosphorescent sensitizer doped in the absorbing bottom layer to improve top-contact lateral OPDs efficiency is discussed.

Freshwater ecosystem degradation in the Amazon and Orinoco river basins is increasing due to rising human population numbers, and large water development projects. Therefore, monitoring ecosystem condition in these rivers of high biodiversity is of global conservation importance. This dissertation evaluated the potential of using river dolphins as indicators of ecosystem condition in large tropical rivers of South America. First, population estimates of river dolphins were obtained by line-strip transect surveys and mark-recapture methods on photo-identifications. Using this information, I identified critical habitat, hotspots, and areas of concern for river dolphins, as well as the relationship between dolphin density and group size estimates with ecological features. Second, I evaluated the relationship between dolphin estimates and human stressors. Higher densities of dolphins occurred in rivers with low indices of overall freshwater degradation, such as rivers with high water quality and the lowest human population numbers. Thus, dolphin density estimates seem to be good indicators of freshwater ecosystem degradation in the Amazon and Orinoco basins. These top predators not only are indicator species, but also have the potential to act as flagship and sentinel species, indicating freshwater ecosystem degradation and stimulating conservation action. This dissertation highlights the large changes in the Amazon and Orinoco that are approaching fast. Indicator, flagship and sentinel species can become science-based conservation tools not to only document freshwater ecosystem degradation, but to raise awareness about broader implications of human stressors on biodiversity and river systems.

The transition for any executive into a new appointment is a challenge. This transition for the newly appointed Chief Information Officer (CIO) is especially challenging given the complexity and ambiguous nature of their role. Investment in information technology (IT) has steadily increased over the past twenty years and contributes to enabling business changes that drive organizational performance improvements. The role of the Chief Information Officer (CIO) has evolved into an executive who holds significant responsibility for leading the organization in realizing these investment benefits. Therefore unsuccessful CIO transitions can negatively impact the extent to which the organization’s IT benefits are fully realized. This research has one objective: to increase our understanding of the process of taking charge for the newly appointed Chief Information Officer (CIO). This increased understanding contributes to academic research as well as provides insights to practicing CIOs that will increase their probability of successfully taking charge of a new appointment. The project explores this phenomenon in depth from both the CIO’s and non-IT executive’s (CxO) perspective through semi-structured interviews with 43 executives. Participants included twenty-one Chief Information Officers and twenty-two C-suite, non-IT executives. The study integrates concepts from role theory and leader socialization with CIO leadership challenges. Findings indicate that the newly appointed CIO experiences a mutual adjustment process when they take charge. This adjustment occurs within their role set; the IT leadership team, the Chief Executive Officer (CEO) and the other top management team members (CxOs). The data suggests that CIOs experience three overlapping phases of taking charge; Entry, Stabilization and Renewal. These phases result in confidence, credibility and legitimacy as a new leader in the organization. The data further reveals that the type of transition (Start-up, Turnaround, Realignment or Success-sustaining) encountered by the CIO is a significant influence on the taking charge process. CIO socialization is influenced heavily by their role set and the expectations within it. CIOs will encounter CxO peers with varying preferences on interaction style and focus. In addition the CxOs in the study identified three different views of CIOs that reinforce the role ambiguity for the newly appointed CIO. The study reveals that CIOs experience organizational socialization in two domains of leadership. These domains are supply-side and demand-side leadership. The data suggests that supply-side socialization occurs prior to demand-side socialization. These socialization outcomes are dependent on transition type. This research extends previous work done on CIO transitions by identifying phases, activities and outcomes. An additional contribution is the first empirical model of new CIO socialization. Leader socialization research is enhanced with the study of a non-CEO executive. This model contributes a deeper understanding of the mutual adjustment process experienced by a newly appointed CIO. Practicing CIOs can apply these findings in developing transition plans and actions for taking a new appointment. The CxO types and attitudes can inform the newly appointed CIO on customizing their relationship building approaches. Understanding that taking charge requires 2-3 years can lead to more realistic expectations of the executive. The findings of this study can lead CIOs to a higher probability of success in taking charge of a new appointment.

Top Tensioned Riser (TTR) and Steel Catenary Riser (SCR) are often used in a floating oil/gas production system deployed in deep water for oil transport. This study focuses on the improvements to the existing numerical code, known as CABLE3D, to allow for static and dynamic simulation of a TTR connected to a floating structure through a tensioner system or buoyancy can, and a SCR connected to a floating structure through a flex joint. A tensioner system usually consists of three to four cylindrical tensioners. Although the stiffness of individual tensioner is assumed to be linear, the resultant stiffness of a tensioner system may be nonlinear. The vertical friction at a riser guide is neglected assuming a roller is installed there. Near the water surface, a TTR is forced to move due to the motion of the upper deck of a floating structure as well as related riser guides. Using the up-dated CABLE3D, the dynamic simulation of TTRs will be made to reveal their motion, tension, and bending moment, which is important for the design. A flex joint is approximated by a rotational spring with linear stiffness, which is used as a connection between a SCR and a floating structure or a connection between a TTR and the sea floor. The improved CABLE3D will be integrated into a numerical code, known as COUPLE, for the simulation of the dynamic interaction among the hull of a floating structure, such as SPAR or TLP, its mooring system and riser system under the impact of wind, current and waves. To demonstrate the application of the improved CABLE3D and its integration with COUPLE, the related simulation is made for ‘Constitution’ SPAR under the met-ocean conditions of hurricane ‘Ike’. The mooring system of the Spar consists of nine mooring lines and the riser system consists of six TTRs and two SCRs.

No description available.

Till följd av dagens dynamiska omvärld ställs allt högre krav på organisationers förmåga att effektivt leda och genomföra organisationsförändringar. Dock är det få organisationer som framgångsrikt förmår genomföra förändringar då de saknar den nödvändiga kunskapen och kompetensen. Om organisationer ska förbättra sina möjligheter att lyckas och uppnå hållbara resultat, krävs det en ökad förståelse för de olika strategierna som kan tillämpas under förändringsprocessen, samt de fördelar och nackdelar dessa inbegriper.   Syftet med studien är att bidra med en mer balanserad belysning av de fördelar och nackdelar som förknippas med den ledningsledda respektive delaktiga förändringsstrategin. Som ett led i detta ska vi analysera Swedbanks val av förändringsstrategi och via kvalitativa intervjuer försöka skapa en ökad förståelse för det undersökta fenomenet.   Studien är av kvalitativ karaktär och empirin består av data från fem intervjuer med anställda i fallföretaget Swedbank som för närvarande genomgår en omfattande omorganisering. Respondenterna utgörs av Swedbanks Senior Advisor och Acting Head of Customer Intelligence, samt en regionchef och två kontorschefer.   Studien har bidragit med en mer balanserad och nyanserad syn på de fördelar och nackdelar som lyfts fram inom teorin beträffande den ledningsledda respektive deltagande förändringsstrategin. Av studien framgår att det finns starka indikatorer på att en syntes av de båda förändringsstrategierna kan vara att föredra under förändringsprocesser. / Background As a result of today's dynamic business environment there is a greater demand on organizations ability to manage and implement organizational changes. However, few organizations are able to successfully implement changes because they lack the knowledge and qualification. If organizations are to increase their chances to succeed and achieve sustainable results, it will require a greater understanding of the different change strategies that can be applied during the process, and the advantages and disadvantages these consist of. Aim The aim of the study is to highlight the advantages and disadvantages associated with management-led and participative change strategies in a more balanced way. To do this, we will analyze Swanbank’s choice of change strategy and through qualitative interviews try to create a better understanding of the studied phenomenon. Methodology This study has a qualitative approach and the empirical data consists of material from five interviews with individuals working at Swedbank, which is currently undergoing a major reorganization. The respondents comprise of Swedbank’s Senior Advisor and Acting Head of Customer Intelligence, and also a regional manager and two office managers. Conclusion The study has provided a more balanced and nuanced view of the advantages and disadvantages highlighted in previous studies concerning the management-led and participative change strategy. The study shows that there are strong indicators that a synthesis of the two change strategies may be preferable for achieving change.

Mineral dust aerosols, the tiny soil particles in the atmosphere, play a key role in the atmospheric radiation budget through their radiative and cloud condensation nuclei effects. It is therefore important to evaluate the radiative forcing of mineral dust and subsequent changes in atmospheric dynamics. The Weather Research and Forecasting with Chemistry (WRF/Chem) regional model with the integrated dust modules and available observations have been used to investigate the three-dimensional distribution of mineral dust over Australia. Additionally, the WRF/Chem model was used to estimate the direct radiative forcing by mineral dust over Australia. Particular emphasize has been given to direct radiative feedback effect of mineral dust on boundary layer dynamics. Two dust emission schemes embedded within the WRF/Chem model have been utilized in this study: the dust transport (DUSTRAN) and the Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) schemes. The refractive index of mineral dust depends on the mineralogy, size and composition of dust over a given region. The refractive index of mineral dust for shortwave radiation was considered to be wavelength independent and set based on previous mineralogical studies over North Africa and Australia. However, the refractive index of mineral dust for longwave radiation was considered to be wavelength dependent and to vary for 16 longwave spectral bands. Model results were compared with observations to validate the performance of the model, including satellite datasets from the Moderate Resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging SpectroRadiometer (MISR) and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), as well as ground-based measurements obtained from air quality monitoring sites over Australia. The major results can be summarized as follows: (1) Lake Eyre Basin is the most important source of dust in Australia, with a peak activity identified to be during austral spring and summer, and dust emission within the basin is often associated with the passage of dry cold fronts; (2) Mineral dust from Lake Eyre Basin can be transported long distances to southeastern Australia in association with eastward propagating frontal systems, reaching as far as New Zealand and beyond, and to northern tropical Australia by postfrontal southerly winds, and subsequently towards northwestern Australia and the Indian Ocean by southeasterly trade winds; (3) Australian dust plumes are mainly transported in the lower atmosphere, although variation of boundary layer depth during the passage of cold frontal systems, as well as ascending motion at the leading edge of these systems and descending motion where postfrontal anticyclonic circulation is dominant contribute to the vertical extent of mineral dust aerosols; (4) the shortwave direct radiative effect of mineral dust results in cooling of the atmosphere from the surface to near the boundary layer top, but warming of the boundary layer top and lower free atmosphere; (5) changes in the vertical profile of temperature result in an overall decrease of wind speed in the lower boundary layer and an increase within the upper boundary layer and lower free atmosphere; (6) the longwave warming effect of mineral dust partly offsets its shortwave cooling effect at the surface. This compensation is significantly larger over and immediately downwind of dust source regions where coarse particles are more abundant, as they have stronger interaction with longwave radiation emitted from the Earth’s surface; (7) both shortwave and longwave radiative forcing by mineral dust was found to have a diurnal variation in response to changes in solar zenith angle and in the intensity of longwave radiation, respectively; (8) the absorptive nature of dust was shown to be associated with the shortwave heating of the atmosphere; (9) on the other hand, longwave cooling of the atmosphere was identified because absorption of longwave radiation by dust is less than its emission to the surface and top of the atmosphere (TOA).