Browsing PhD e-theses by Title
Now showing items 654-656 of 656
Young people and the informal economy: understanding their pathways and decisionmaking within the economyThis is a study of a group of young people that explores their journeys into, and experiences within, the informal economy. Evidence has shown that young people have always been more disadvantaged in a context of high levels of unemployment, limited job opportunities and entitlement to welfare benefits. As an alternative to low paying jobs with poor working conditions, and in addition to strict conditions for claiming benefits, some young people are making the decision to engage in criminal ways of generating income. This study examines the experiences of twenty-six young people from Luton and Cambridge who had engaged in begging, drug dealing and sex work as alternative forms of ‘work’ in their transitions to adulthood. It explores the structural, cultural and biographical factors that influence their informal career decision-making processes, by drawing on Bourdieu’s social field theory. By examining the lived experiences of these young people, the study throws more light on the role of structure and personal agency in the decisions the young people made in engaging in the informal economy. These young people wanted to be seen as ‘normal’ young people. Most were hardworking, and ambitious, and their engagement in informal economic activities was often a ‘means to an end’. This study also identifies strategies that were employed by the young people for their successful navigating of the economy, and highlights the importance of elements like trust, respect and knowledge in their negotiations. It assesses how the issue of risk was managed with the help of what was seen to be an unwritten code of conduct in the field. The study also identified a hierarchy within the field, which was determined by the individual participants, depending on their personal perceptions and perspectives. The data was collected using semi-structured interviews, over a period of a year. The process of collecting data was long and difficult, highlighting the ethical and methodological challenges of conducting research with a ‘hidden’ population. The findings throw new light on the unique challenges young people face both in the formal job market, and in accessing welfare support, in light of the significant changes to social policy in the UK.
Youthwork@cyberspace.com : unsanctioned social network site connections between youth work practitioners and young peopleSocial network sites are online spaces that can be used for interaction between young people and youth work practitioners. The focus of this thesis is social network site interaction that falls outside the guidance of the local authority, through unsanctioned interaction on practitioners’ personal but also work profiles. Twenty one practitioners and fourteen young people were interviewed, using a semi-structured interview guide. Three inter-linked themes emerged through the research process; space and place; trust development and boundary management. Young people wanted to interact with some practitioners through the practitioners' personal profiles but the majority of practitioners would rather interact with young people through work profiles. Young people viewed and trusted these practitioners as friends and were willing to share their personal, but also socially intimate information with them. Most practitioners viewed their relationship with young people as a professional relationship and aimed to maintain personal and professional boundaries. However, practitioners did not extend this same awareness to the boundaries of young people. This was further confirmed by the practice of client searching through a variety of profiles to access socially intimate information of young people. Where practitioners and volunteers lived and worked in the same geographical spaces, these multiple relationships increased uncertainty with regards to unsanctioned SNS interaction. Other practitioners were either fearful or opportunistic of these relationships and used them to gain further socially intimate information about young people or turned a blind eye to these relationships due to uncertainty of how to respond. This thesis extends knowledge and theory concerning youth work practice at a time of change, and also new spaces for interaction online. Civic courage and incentives that outweigh deterrents lead to unsanctioned connections for practitioners. For young people this interaction was based on the type of friendship they perceived they had with practitioners. Studying perceptions regarding this interaction revealed cycles of perpetual negative practice, personal and socially intimate boundaries and different views on the type of relationship that young people and practitioners developed with each other.
λ-connectedness and its application to image segmentation, recognition and reconstructionSeismic layer segmentation, oil-gas boundary surfaces recognition, and 3D volume data reconstruction are three important tasks in three-dimensional seismic image processing. Geophysical and geological parameters and properties have been known to exhibit progressive changes in a layer. However, there are also times when sudden changes can occur between two layers. A-connectedness was proposed to describe such a phenomenon. Based on graph theory, A-connectedness describes the relationship among pixels in an image. It is proved that A-connectedness is an equivalence relation. That is, it can be used to partition an image into different classes and hence can be used to perform image segmentation. Using the random graph theory and A-connectivity of the image, the length of the path in a A-connected set can be estimated. In addition to this, the normal Aconnected subsets preserve every path that is A-connected in the subsets. An O(nlogn) time algorithm is designed for the normal A-connected segmentation. Techniques developed are used to find objects in 2D/3D seismic images. Finding the interface between two layers or finding the boundary surfaces of an oil-gas reserve is often asked. This is equivalent to finding out whether a A-connected set is an interface or surface. The problem that is raised is how to recognize a surface in digital spaces. A-connectedness is a natural and intuitive way for describing digital surfaces and digital manifolds. Fast algorithms are designed to recognize whether an arbitrary set is a digital surface. Furthermore, the classification theorem of simple surface points is deduced: there are only six classes of simple surface points in 3D digital spaces. Our definition has been proved to be equivalent to Morgenthaler-Rosenfeld's definition of digital surfaces in direct adjacency. Reconstruction of a surface and data volume is important to the seismic data processing. Given a set of guiding pixels, the problem of generating a A-connected (subset of image) surface is an inverted problem of A-connected segmentation. In order to simplify the fitting algorithm, gradual variation, an equivalent concept of A-connectedness, is used to preserve the continuity of the fitted surface. The key theorem, the necessary and sufficient condition for the gradually varied interpolation, has been mathematically proven. A random gradually varied surface fitting is designed, and other theoretical aspects are investigated. The concepts are used to successfully reconstruct 3D seismic real data volumes. This thesis proposes A-connectedness and its applications as applied to seismic data processing. It is used for other problems such as ionogram scaling and object tracking. It has the potential to become a general technique in image processing and computer vision applications. Concepts and knowledge from several areas in mathematics such as Set Theory, Fuzzy Set Theory, Graph Theory, Numerical Analysis, Topology, Discrete Geometry, Computational Complexity, and Algorithm Design and Analysis have been applied to the work of this thesis.