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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Die Kompetenzschule ELSYS an der Research Academy Leipzig

Stoppe, Sebastian, Zlotowski, Marc, Schlegel, Martin 14 January 2014 (has links) (PDF)
Nach erfolgreicher Antragstellung wurde zum 1. Juli 2010 die Kompetenzschule ELSYS (Employability and Leadership Skills for Young Saxon Researchers) an der Research Academy Leipzig eingerichtet. Die Finanzierung der Kompetenzschule erfolgte zu 100 Prozent aus Mitteln des Europäischen Sozialfonds (ESF) gemäß der Richtlinie ESF Hochschule und Forschung des Sächsischen Staatsministeriums für Wissenschaft und Kunst (SMWK). Hierbei sollte das Ziel einer nachhaltigen Verstetigung des Projekts an der Universität verfolgt werden. Die Mittelzuweisung und Ausgabenprüfung gemäß der Förderrichtlinie erfolgten durch die Sächsische Aufbaubank (SAB). Der Bericht umfasst die Aktivitäten und Ergebnisse des ersten Förderzeitraumes vom 1. Juli 2010 bis zum 30. Juni 2013. Es wird dargestellt, wie die Lern- und Weiterbildungsinhalte und -strategien der Kompetenzschule dazu beigetragen haben, ein umfangreiches Angebot für den Erwerb von (überfachlichen) Handlungskompetenzen für Promovierende und Postdocs nachhaltig zu entwickeln. Ergebnisse und Alleinstellungsmerkmale werden anhand des Konzepts und der Struktur der Kompetenzschule ELSYS herausgearbeitet und bewertet. Ein Konzept für den Förderzeitraum bis 2014 und darüber hinausreichende Entwicklungsstrategien werden skizziert.
82

Sensor Fusion for Automotive Applications

Lundquist, Christian January 2011 (has links)
Mapping stationary objects and tracking moving targets are essential for many autonomous functions in vehicles. In order to compute the map and track estimates, sensor measurements from radar, laser and camera are used together with the standard proprioceptive sensors present in a car. By fusing information from different types of sensors, the accuracy and robustness of the estimates can be increased. Different types of maps are discussed and compared in the thesis. In particular, road maps make use of the fact that roads are highly structured, which allows relatively simple and powerful models to be employed. It is shown how the information of the lane markings, obtained by a front looking camera, can be fused with inertial measurement of the vehicle motion and radar measurements of vehicles ahead to compute a more accurate and robust road geometry estimate. Further, it is shown how radar measurements of stationary targets can be used to estimate the road edges, modeled as polynomials and tracked as extended targets. Recent advances in the field of multiple target tracking lead to the use of finite set statistics (FISST) in a set theoretic approach, where the targets and the measurements are treated as random finite sets (RFS). The first order moment of a RFS is called probability hypothesis density (PHD), and it is propagated in time with a PHD filter. In this thesis, the PHD filter is applied to radar data for constructing a parsimonious representation of the map of the stationary objects around the vehicle. Two original contributions, which exploit the inherent structure in the map, are proposed. A data clustering algorithm is suggested to structure the description of the prior and considerably improving the update in the PHD filter. Improvements in the merging step further simplify the map representation. When it comes to tracking moving targets, the focus of this thesis is on extended targets, i.e., targets which potentially may give rise to more than one measurement per time step. An implementation of the PHD filter, which was proposed to handle data obtained from extended targets, is presented. An approximation is proposed in order to limit the number of hypotheses. Further, a framework to track the size and shape of a target is introduced. The method is based on measurement generating points on the surface of the target, which are modeled by an RFS. Finally, an efficient and novel Bayesian method is proposed for approximating the tire radii of a vehicle based on particle filters and the marginalization concept. This is done under the assumption that a change in the tire radius is caused by a change in tire pressure, thus obtaining an indirect tire pressure monitoring system. The approaches presented in this thesis have all been evaluated on real data from both freeways and rural roads in Sweden. / SEFS -- IVSS / VR - ETT
83

Problems in nonlinear Bayesian filtering

Pasha, Syed, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW January 2009 (has links)
This dissertation presents solutions to two open problems in estimation theory. The first is a tractable analytical solution for problems in multi-target filtering which are too complex to solve using traditional techniques. The second explores a new approach to the nonlinear filtering problem for a general class of models. The approach to the multi-target filtering problem which involves jointly estimating a random process of the number of targets and their state, developed using the probability hypothesis density (PHD) filter alleviates the intractability of the problem by avoiding explicit data association. Moreover, the notion of linear jump Markov systems is generalized to the multiple target case to accommodate births, deaths and switching dynamics to derive a closed form solution to the PHD recursion for this so-called linear Gaussian jump Markov multi-target model. The proposed solution is general enough to accommodate a broad class of practical problems which are deemed intractable using traditional techniques. Based on this closed form solution, an efficient method is developed for tracking multiple maneuvering targets that switch between multiple models without the need for gating, track initiation and termination, or clustering for extracting state estimates. The approach to the nonlinear filtering problem explores the framework of the virtual linear fractional transformation (LFT) model which localizes the nonlinearity to the feedback with a simple and sparse structure. The LFT is an exact representation for any differentiable nonlinear mapping and therefore amenable to a general class of problems. An alternative analytical approximation method is presented which avoids linearization of the state space model. The uncorrelated structure of the feedback connection gives of the state space model. The uncorrelated structure of the feedback connection gives better second-order moment approximation of the nonlinearly mapped variables. By arranging the unscented transform in the feedback, the prediction and estimation steps are derived in closed form. The proposed filters for the discrete-time model and continuous-time dynamics with sampled-data measurements respectively are shown to be robust under highly nonlinear and uncertain conditions where standard analytical approximation based filters diverge. Moreover, the LFT based filters are efficient for online implementation. In addition, the LFT framework is applied to extend the closed form solution of the PHD recursion to the nonlinear jump Markov multi-target model.
84

While on my Journey: A Life Story Analysis of African American Women in Pursuit of their Doctoral Degrees in the Southwest

January 2013 (has links)
abstract: The purpose of this study is to explore the lived experiences of African American women in pursuit of doctoral degrees in the southwest, their challenges and motivations, and plans for the their next chapter. Drawing from critical race theory and a sociocultural framework, this qualitative study uses Dan McAdams' Life Story Interview (McAdams, 2005) to explore the journeys of these high achieving minority women and how achievement is conceptualized in their stories. Particular emphasis is placed on their critical events, challenges, and alternative futures. Seven separate themes (parental support and advocacy in early education, improved experiences among other African American students, perseverance through struggles/experiences led to purpose, poor department support, family support, impact of spirituality, and relocation and desire to give back) emerged that address three main research questions. Implications for findings and suggestions for future research are offered. / Dissertation/Thesis / Ph.D. Educational Psychology 2013
85

Untersuchung der Transportvorgänge des Prolyl-Hydroxylase-Hemmers ICA an den Transportern OAT1, OAT2, OAT3 und OAT4 von proximalen Nierentubuluszellen / Examination of transport processes of the prolyl hydroxylase inhibitor ICA on the transporters OAT1, OAT2, OAT3 and OAT4 of renal proximal tubule cells

Schulz, Kei 05 December 2017 (has links)
No description available.
86

Nitrogen in the Earth System: planetary budget and cycling during geologic history

Johnson, Benjamin William January 2015 (has links)
The distribution and geologic history of nitrogen on Earth is poorly known. Traditionally thought to be an inert gas, with only a small but important biologic cycle, geochemical investigation highlights that it can also be present in rocks and minerals. Even at low concentrations, the great mass of the solid Earth allows for the possibility of substantial N mass and cycling in the geosphere over Earth history. Thus, the assumption that N on the surface of the Earth has remained in steady state over Earth history can be questioned. The research goals of this thesis are to investigate the Earth System N cycle using both large- and small-scale approaches. I present a comprehensive literature compilation to ascertain the N budget of Earth. Determining the total abundance of N in all reservoirs of the Earth, including the atmosphere, oceans, crust, mantle, and core is crucial to a discussion of its cycling in the past. This budget study suggests that the majority of planetary N is likely in the core, with the Bulk Silicate Earth a more massive reservoir than the atmosphere. I also present experimental data and data from lunar samples as added context. As quantification of geologic N is difficult, I present research detailing the adaptation of a fluorometric technique common in aquatic geochemistry for use on geologic samples. I compare fluorometry analysis of geochemical standards to several other techniques: colourimetry, elemental analyzer mass spectrometry, and neutron activation analysis. Fluorometry generally behaves well for crystalline samples, and is a relatively quick and easy alternative to more expensive or intensive techniques. As a preliminary application, I have determined a N budget estimate for the continental crust based on analysis of crystalline crustal rocks and glacial tills from North America. This budget is consistent with published work, suggesting about 2 × 1018 kg N, or half a present atmospheric mass of N, is in the continental crust. I also present a geochemical study measuring N-isotopes and redox sensitive trace elements from a syn-glacial unit deposited during the the Marinoan Snowball Earth. Snowball Earth events were the most extreme glaciations in Earth history. The measurements presented herein are the first to quantify biologic activity via N-isotopes as well as the redox state of the atmosphere and ocean using trace elements from this intriguing time period in Earth history. The data suggests that there was active N- fixing in the biosphere, persistent but limited O2, nitrification, and nearly quantitative denitrification during the glaciation. After the glacial interval, O2 levels increased and denitrification levels dropped, indicated by near-modern δ15N values. The combined use of N-isotope with redox sensitive trace elements provides a more nuanced and comprehensive view in reconstructing past ocean and biologic conditions. Lastly, I present an Earth-system N cycle model with nominal results. Previous modelling efforts have agreed with the traditional notion that atmospheric N-levels have remained constant over geologic time. This is in contrast with modern geochemical evidence suggesting net transport of N from the surface into the mantle. The aim, in turn, of this model is to model N cycling over Earth history by explicitly incorporating both biologic and geologic fluxes. The model is driven by a mantle cooling history and calculated plate tectonic speed, as well as a prescribed atmospheric O2 evolution history. This approach is the first of its kind, to my knowledge, and produces stable model runs over Earth history. While tuning and sensitivity studies may be required for publishable results, nominal runs are compelling. In model output, atmospheric N varies by an factor of 2 − 3 over Earth history, and the availability of nutrients (i.e., PO4) exerts a strong control on biologic activity and movement of N throughout the Earth system. Such a planetary perspective on N serves as an entry point into discussions of planetary evolution as a whole. With the great increase in the number of discovered exoplanets, the scientific community is charged with developing models of planetary evolution and factors that promote habitability. Comparison of Earth to its solar system neighbours and future data on exoplanets will allow a system of evolution pathways to be explored, with the role of N expected to be prominent in discussions of habitability and planetary evolution. / Graduate / 0996 / 0425 / bwjohnso@uvic.ca
87

An ecosystem-based spatial conservation plan for the South African sandy beaches

Harris, Linda Rozanne January 2012 (has links)
An ecosytem-based spatial conservation plan for the South African sandy beaches. Sandy beaches are valuable ecosystems. They support a collection of species that is unique, comprising many endemic species, and provide a number of key ecosystem goods and services, including scenic vistas for human recreation, nesting sites for turtles and birds, and important areas for biogeochemical recycling, water filtration and purification. However, sandy beaches have not been well understood or appreciated as ecosystems, and consequently have a legacy of poor coastal management. In many instances this has lead to a "tyranny of small decisions", where multiple, seemingly insignificant management decisions and actions have resulted in complete transformation and degradation of the shoreline in several places. In addition to inappropriate management strategies, beaches are also poorly represented in conservation areas. Further, where they are recognised as being "conserved" in marine protected areas, this often is a false sense of protection because the far more sensitive dune portion of the littoral active zone is invariably not included in the reserve. In short, there is a need for a new way to approach sandy beach conservation and management that includes the system (dunes, intertidal beaches and surf zones) as a whole. On one hand, the approach should make provision for use of the abundant natural resources and opportunities associated with sandy shores in ways that are sustainable and contribute to biodiversity stewardship - through ecosystem-based management and marine spatial planning. But, on the other hand, it must simultaneously contribute to securing a sufficient amount of the key ecological attributes of beaches (habitats, biodiversity and processes) in a network of reserves, to ensure that the ecosystem, natural resources, and services all persist in perpetuity - through systematic conservation planning. The aim of this Thesis is to integrate these into a single approach, which I call ecosystem-based spatial conservation planning for sandy beaches, using the South African sandy shores as a case study. To achieve this broad aim, the Thesis is divided into three parts. Part 1 deals with establishing baseline information by quantifying spatial patterns in sandy beach habitats (Chapter 1), biodiversity, key assemblages and processes, and outstanding physical features (Chapter 2). First, mapping sandy beach habitats is a challenge given the vast, linear extent of shorelines and significant resources required to complete the project. Therefore, a novel approach was derived using statistical techniques (conditional inference trees) to identify physical features of beaches that can be observed on Google Earth (or similar) imagery, and that can provide good predictions of beach morphodynamic (habitat) types. Based on the results of this analysis, sandy beaches (and all other coastal habitat types) were mapped digitally in ArcGIS. Second, spatial patterns in sandy beach biodiversity (vertebrates, macrofauna, microflora and foredune plants) were mapped by compiling existing data on the distributions of key species that have been well studied or mapped previously (vertebrates and foredune plants), and by niche modelling (macrofauna and microflora). For the latter, data from all previous sandy-beach sampling events in South Africa were compiled from published and unpublished sources, and supplemented with additional sampling of 23 beaches along the national shoreline, targeting macrofauna and phytoplankton. Altogether, the macrofauna database comprised data from 135 sites and 186 sampling events, and the microflora (phytoplankton and microphytobenthos) database comprised data from 73 sites and 510 samples. The probabilistic distribution of each "resident" species (present at 10 or more sites) was modelled in MaxEnt version 3.3.3k, probability thresholds were determined statistically (to convert the data into predicted presence-absence), and displayed as a digital map. A composite biodiversity map was compiled, and key trends in species richness and endemism along the national shoreline were quantified. To supplement biodiversity proper, additional valued-features of sandy beaches were mapped, including: important assemblages; unique habitat features; and sites associated with key ecological processes. Part 2 considers threats to sandy beaches in the context of deriving an appropriate management strategy that seeks to provide for use of the coast, but in a way that has least overall impact to the ecosystem. A method for assessing cumulative threats to sandy beaches is adapted from an existing framework (Chapter 4). This entailed compiling a list of threats to beaches, and scoring these (out of 10) in terms of the severity of their respective impacts to beaches, and how long it would take the ecosystem to recover should the threat be removed. The scoring was based on the collective expert opinion of the scientific community working on sandy beaches, at a workshop during the VIth International Sandy Beach Symposium 2012. To standardize the scores and ensure broad applicability, a base case scenario of a pristine beach was established, and maximum theoretical scores were provided for this context. The method for integrating these scores into a spatial, cumulative threat assessment was then determined. In Chapter 5, the maximum theoretical scores (from Chapter 4) were down-scaled to suit the current threat regime to the South African sandy beaches, and the cumulative threat assessment methodology was applied. From this analysis, the most threatened beaches in South Africa, and the most important threats were highlighted. A decision-support tool for managers was derived from the site-specific cumulative threat-impact scores, based first on the degree of permanent habitat transformation, and second on the cumulative impact of other stressors where the impacts these stressors have could potentially be mitigated or ameliorated. Part 3 concerns conservation of beaches explicitly. It addresses how much of which valued features of beaches is required to ensure their long-term persistence, and the design of a network of beaches in South Africa that are of ecological importance and should be set aside as reserves. Conservation targets are set in Chapter 6, using species-area curves to determine a baseline percentage-area required to protect sandy beach habitats, which is modified using heuristic principles based on habitat rarity and threat status (from a recent national assessment). A fixed target was applied to all species, also modified by heuristic principles, and another fixed target was applied to key assemblages and processes.
88

An in-depth study of entrepreneurs and PhD students' practical processes and self identities : are they really two different species?

Heywood, Dale Carol January 2012 (has links)
This research explores two polarised occupations; entrepreneurs and PhD research students. It exposes similarities and differences between them which specifically defuse the species premise that all entrepreneurs are different and often portrayed as superior to the rest of society and that they, entrepreneurs, are diametrically opposed to PhD research students in the objectives of their work and ultimate intentions for that work. An explorative, interpretive approach is taken which helps illuminate how people understand, interpret and employ their self identity to qualify the practices of both entrepreneurship and PhDship. This methodology enabled exploration of perceptions of self and role in a small sample of people of different age, gender, class, ethnicity and economic standing of two externally polarised occupational groups. This approach permits a compare and contrast of both similarity and differences between these two roles. Qualitative interviews were conducted with six entrepreneurs and six current PhD students from two North West of England research-led universities in a multitude of disciplines and industrial sectors. Numerous existing studies have compared entrepreneurs to managers, to leaders and more recently to business students. Other studies have aimed to ascertain why some people become an entrepreneur as oppose to a salaried employee. To date, no previous research that I am aware of considers doctoral researchers in the same way, that is, as individuals making a contribution to society that is of social, economic and intellectual benefit by furthering knowledge and innovation. The findings from this research show that there are overwhelming similarities between these two occupations in both their practical processes and their sense of self. In fact, there are more differences within the two occupations than between them. It is suggested that identification of individual purpose may prove a valuable determinate of whether people select either of these occupations for socioeconomic reasons or for socioemotional ones. The contribution this research and its findings make is in the recognition of the different purposes individuals express as their primary reason for engaging in either PhD research work or venture formation. This recognition helps expand our understanding beyond the existing opportunity-necessity or push-pull hypothesis to demonstrate a more sophisticated intention based form of inquiry. Individuals in both occupations are subsequently sub categorised as conformists, alterpreneurs, changemakers or vocationalists. Conformists aim to meet perceived social expectations of them; Alterpreneurs are those who buy-a-job; Changemakers intend to improve or fix a self identified problem; Vocationalists intend to develop their skill and expertise in their chosen field.
89

Perceptions of Transformation and Quality in Higher Education: A Case Study of PhD Student Experiences

Groen, Jovan 31 January 2020 (has links)
Stemming from increased levels of participation and diversity of the student base (Biggs & Tang, 2011) and growing scrutiny on the quality of university degrees (Crowley, 2013; Marr, 2013), governments have begun putting in place mechanisms to monitor and support quality in higher education. Over the last few decades, a notion of quality that has gained traction in the scholarly community is that of quality in terms of enhancement and transformation (Cheng, 2017; Houston, 2008; Williams, 2016). Guided by the discourses of Transformative Learning Theory (Mezirow, 2000) and transformative conceptions of quality in higher education (Harvey & Green, 1993), this study examined graduate student learning experiences and perceptions of quality. Of further interest was the extent to which these learners were living the intended transformation that academic programs are seeking to foster. Using a multiple case-study design, Seidman’s (2013) three-stage interview protocol served as primary source of data from a sample of six PhD candidates across three faculties. Secondary data sources included collected documents, a reflexivity journal and field notes. A within-case analysis was performed for each case and compared via a cross-case analysis. Institutional characterizations of quality were examined across 25 artifacts via a document analysis. The four principal factors that characterized the PhD candidate learning experience emerged as the significance of intentional individualized guidance, becoming an independent scholar, the importance of social interactions and community, and the transformative nature of learning. Gaps were identified between institutional intent and the learner experience. However, complementarity between discourses of transformation appeared to offer bridges between the macro-level institutional orientation toward fostering student transformation and the micro-level transformative learning experiences lived by students. The dissertation makes conceptual, methodological and empirical contributions to the domains of postsecondary quality and transformative learning. Implications for policy related to quality assurance as well as practice in program development and doctoral supervision are equally shared.
90

Tracking of Pedestrians Using Multi-Target Tracking Methods with a Group Representation

Jerrelind, Jakob January 2020 (has links)
Multi-target tracking (MTT) methods estimate the trajectory of targets from noisy measurement; therefore, they can be used to handle the pedestrian-vehicle interaction for a moving vehicle. MTT has an important part in assisting the Automated Driving System and the Advanced Driving Assistance System to avoid pedestrian-vehicle collisions. ADAS and ADS rely on correct estimates of the pedestrians' position and velocity, to avoid collisions or unnecessary emergency breaking of the vehicle. Therefore, to help the risk evaluation in these systems, the MTT needs to provide accurate and robust information of the trajectories (in terms of position and velocity) of the pedestrians in different environments. Several factors can make this problem difficult to handle for instance in crowded environments the pedestrians can suffer from occlusion or missed detection. Classical MTT methods, such as the global nearest neighbour filter, can in crowded environments fail to provide robust and accurate estimates. Therefore, more sophisticated MTT methods should be used to increase the accuracy and robustness and, in general, to improve the tracking of targets close to each other. The aim of this master's thesis is to improve the situational awareness with respect to pedestrians and pedestrian-vehicle interactions. In particular, the task is to investigate if the GM-PHD and the GM-CPHD filter improve pedestrian tracking in urban environments, compared to other methods presented in the literature.  The proposed task can be divided into three parts that deal with different issues. The first part regards the significance of different clustering methods and how the pedestrians are grouped together. The implemented algorithms are the distance partitioning algorithm and the Gaussian mean shift clustering algorithm. The second part regards how modifications of the measurement noise levels and the survival of targets based on the target location, with respect to the vehicle's position, can improve the tracking performance and remove unwanted estimates. Finally, the last part regards the impact the filter estimates have on the tracking performance and how important accurate detections of the pedestrians are to improve the overall tracking. From the result the distance partitioning algorithm is the favourable algorithm, since it does not split larger groups. It is also seen that the proposed filters provide correct estimates of pedestrians in events of occlusion or missed detections but suffer from false estimates close to the ego vehicle due to uncertain detections. For the comparison, regarding the improvements, a classic standard MTT filter applying the global nearest neighbour method for the data association is used as the baseline. To conclude; the GM-CPHD filter proved to be the best out of the two proposed filters in this thesis work and performed better also compared to other methods known in the literature. In particular, its estimates survived for a longer period of time in presence of missed detection or occlusion. The conclusion of this thesis work is that the GM-CPHD filter improves the tracking performance and the situational awareness of the pedestrians.

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