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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.
1

Visual analytic extraction of meaning from photo-sharing services for leisure pedestrian routing

Kachkaev, A. January 2014 (has links)
Present-day routing services are able to provide travel directions for users of all modes of transport. Most of them are focusing on functional journeys (i.e. journeys linking given origin and destination with minimum cost) and pay less attention to recreational trips, in particular leisure walks in an urban context. These walks have predefined time or distance and as their purpose is the process of walking itself, the attractiveness of chosen paths starts playing an important role in route selection. Conventional map data that are informing routing algorithms cannot be used for extracting street attractiveness as they do not contain a subjective component, or in other words, do not tell whether or not people enjoy their presence at a particular place. Recent research demonstrates that the crowd-sourced data available from the photo- sharing websites have a potential for being a good source of this measure, thus becoming a base for a routing system that suggests attractive leisure walks. This PhD research looks at existing projects, which aim to utilize user-generated photographic data for journey planning, and suggests new techniques that make the estimation of street attractiveness based on this source more reliable. First, we determine the artifacts in photo- graphic datasets that may negatively impact the resulting attractiveness scores. Based on the findings, we suggest filtering methods that improve the compliance of the spatial distributions of photographs with the chosen purpose. Second, we discuss several approaches of assigning attractiveness scores to street segments and make conclusions about their differences. Finally, we experiment with the routing itself and develop a prototype system that suggests leisure walks through attractive streets in an urban area. The experiments we perform cover Central London and involve four photographic sources: Flickr, Geograph, Panoramio and Picasa. A Visual analytic (VA) approach is used throughout the work to glean new insights. Being able to combine computation and the analytical capabilities of the human brain, this research method has proven to work well with complex data structures in a variety of tasks. The thesis contributes to VA as an example of what can be achieved by means of the visual exploration of data.
2

To travel by older ways : a historical-cultural geography of droving in Scotland

Lowdon, Richard Edward January 2014 (has links)
Taking critical inspiration from A.R.B. Haldane’s pioneering work on The Drove Roads of Scotland, this thesis explores the routes, movement and lively cultural geographies of Scotland’s droving trade. Tracing the journey of a typical drove from the Scottish Highlands, over dangerous river and sea crossings, to the great trysts at Falkirk and Crieff, this thesis examines the embodied intimacies, situated knowledges and mutual understandings developed between herdsmen and their cattle en route. In an effort to augment and enliven a longstanding, but frequently overlooked, ‘shire’ tradition of local landscape research, this thesis places specific emphasis on the personal encounters, skilled practices and cultural exchange which took place between herdsmen and other mobile social groups at key strategic sites such as drovers’ inns, cattle stances and markets. Furthermore, I examine how agrarian ‘improvement’, the introduction of tolls and turnpikes, and the enclosure of drove routes and stance sites, confined and restricted the drovers’ movement, transforming them from valued components of the Scottish economy into mobile ‘outsiders’ whose practices, customary privileges and association with animals rendered them increasingly ‘out of place’ in Scotland’s ‘modern’ commercial landscape.
3

Closely-coupled integration of Locata and GPS for engineering applications

Bonenberg, Lukasz Kosma January 2014 (has links)
GPS has become an almost indispensable part of our infrastructure and modern life. Yet because its accuracy, reliability, and integrity depend on the number and geometric distribution of the visible satellites, it is not reliable enough for the safety of life, environmental or economically critical applications. Traditionally, this has been addressed by augmentation from dedicated support systems, or integration with other sensors. However, from an engineering perspective only expensive inertial systems or pseudolites offer the accuracy required. In the case of pseudolites, the equivalent of ground based satellites, geometry constraints, fading multipath, imprecise clocks, the near-far effect, tropospheric delay and legislative obstructions make them difficult to implement. This thesis takes a step forward, by proposing a loosely coupled integration with Locata, a novel, terrestrial positioning technology, based on the pseudolite concept. It avoids the above pitfalls by utilising frequency and spatially separated antennas and a license-free frequency band, though this comes at the cost of in-bound interference. Its ability to provide stand-alone position and network synchronisation at nanosecond level is used commercially in open-cast mining and in military aviation. Discussion of Locata and GPS technology has identified their shortcomings and main limiting factors as well as the advantages of the proposed integration. During the course of this research, tropospheric delay, planar solution and known point initialisation ambiguity resolution methods have been identified as the main limiting factors for Locata. These are analysed in various static and kinematic scenarios. Discussion also includes ambiguity resolution, noise and interference detection and system performance in indoor and outdoor scenarios. The proposed navigation engine uses a closely coupled integration at the measurement level and LAMBDA as the ambiguity resolution method for Locata and GPS. A combined solution is demonstrated to offer a geometrical improvement, especially in the respect of height determination, with centimetre to decimetre accuracy and a minimum requirement of two signals from any component. This study identifies that proper separation and de-correlation of Locata and GPS ambiguities and better tropospheric models are essential to reach centimetre level accuracy. The thesis concludes with examples of system implementation including: seamless navigation, city-wide network deployment, urban canyons, a long term-monitoring scenario and indoor positioning. This demonstrates how the proposed navigation engine can be an advantage in areas such as: civil engineering, GIS, mobile mapping, deformation, machine navigation and control.
4

Nuclear energy and the low carbon transition

Cooper, Jonathan January 2013 (has links)
This PhD thesis examines the role of nuclear energy in the transition to a low carbon economy in the United Kingdom. Theories of sustainable development, including ecological modernisation, are used to frame its findings and emerging geographies of nuclear new build are explored. Analysis of policy shows that recent narrative from government has been inconsistent on the quantification of the carbon footprint of nuclear energy. The relatively low carbon footprint of nuclear energy, when compared to fossil fuel alternatives, is found to be a significant factor, alongside increased energy security, in the rationale behind the UK government‟s recent programme of new nuclear power stations. Critical analysis of existing life cycle assessments of nuclear power stations is presented. Quantitative and qualitative analysis of questionnaire responses and qualitative analysis of interviews conducted within the nuclear energy sector indicate that approaches to carbon management vary widely. Analysis of public consultation indicates that climate change is one of a range of geographical considerations important in perceptions of nuclear energy. Views on the significance of the relatively low carbon footprint of nuclear energy and on approaches to carbon management in the nuclear industry are analysed in depth. This thesis contributes to a greater understanding of the role of nuclear energy in the UK, of the use of life cycle assessment in nuclear energy and of the role of ecological modernisation in the nuclear industry. The novelty of this thesis lies mainly in its presentation and critical analysis of views on climate change and wider sustainability issues from within the nuclear energy industry itself. It presents geographies of nuclear new build within a specific regional context and proves that UK nuclear energy, in the case of the northwest of England, is not an example of the decide-announce-defend approach to policy making.
5

A molecular study of the bacterioneuston and its role in the air-sea exchange of trace gases

Franklin, Mark P. January 2001 (has links)
The two-way transfer of gases between oceans and air exerts an important control on the atmospheric inventories of climatically active gases such as CO2, CH4 and N20. Numerous physical variables are important to gas transfer at the sea surface and have complex interactions. Because of this, our current knowledge of the gas exchange process remains somewhat limited. Such a situation is urgently in need of attention if the effects of global change into the 21st century are to be adequately addressed. The major rate-limiting step in sea-air gas exchange is slow molecular transport across the so-called "surface microlayer", a region only tens of microns thick at the sea-air interface formed by chemical and microbiological components. This environment is microbiologically distinct from the underlying water, containing enhanced populations of marine bacteria that have only been identified in recent years following advances in molecular identification. In such a microbiologically rich environment, active bio-cycling of gases such as CO2 and CH4 might reasonably be expected to impact their sea-air transfer rates, but this has never previously been demonstrated. We examined directly the microbiological nature of the sea-surface microlayer for the first time and evaluated its potential for modifying the sea-air flux of CH4, using our expertise in molecular microbiology and air-sea gas exchange. Microlayer (neuston) and subsurface (pelagic) seawater samples (North Sea) were collected and subsequent DNA extracts used to construct clone libraries and for subsequent identification of microbiologically active sites specific to CH4-oxidising microbes. The results showed significant differences in the microbial communities of the neuston and pelagic samples, with Vihrio and Pseudoalteromonas spp. dominating the neuston layer. We subsequently examined the potential role methanotrophic bacteria in the sea-air exchange of CH4 in controlled experiments in a laboratory gas exchange tank in which the CH4 compositions of the air and water phases and the methanotroph content of the water could be selected and modified. Our results showed a small but significant enhancement of sea-air CH4 exchange in the presence of methanotrophic bacteria. This suggests that a previously ignored, small bacterial consumption term should be taken account of in sea- air CH4 exchange and that similar "sinks" may apply for other trace gases at the sea surface. If so, current gas exchange models may include errors that could potentially compromise global trace gas budgeting.
6

The political ecology and economy of protected areas and violence : a case study of the conflict of the Kivus in the Democratic Republic of Congo

Rainer, Helga January 2013 (has links)
The role that national parks play in violent conflict has rarely been discussed. Conflict literature focuses on the interaction of specific natural resources on the initiation and perpetuation of war and debate has emphasised the degree to which resource scarcity and abundance are pertinent. The role of space, particularly environmentally-significant areas, in shaping these trajectories has been subject to limited interrogation. Drawing from political economy literature, the dissertation explores the relationship between occupation of these spaces by armed groups and the desire to acquire financial and material resources. Furthermore, by situating the study sites within their historical and political context, the dissertation also investigates linkages to political ecology models which seek to explain how environmental changes shape wider political and economic processes and how they in turn shape environmental change. This work undertakes a case study approach, focussing on two national parks in Eastern Democratic Republic of Congo that have been subject since the 1990s to the world’s deadliest conflict in the post-World War II era. By mapping conflict related health data in proximity to the case study sites, comparisons between the two sites were possible due to similar geographic attributes (namely protected area status) and political context. Positive linkages between levels of violence as a result of the armed conflict were established across both sites. Higher levels of violence in proximity to the national park that lacked valuable conflict-related resources point to the relative importance of location versus the economic benefit of occupying these spaces. This is substantiated by qualitative analysis across the two sites and a household survey around one. Therefore, it is concluded that national parks influence violence by virtue of their status as state-owned entities; by their possession of valuable resources; and by the strategic value of their location. Hence, it may be argued that the role of environmentally-significant spaces in armed conflict is worthy of further empirical analysis in studies of political ecology.
7

The economic impact of uncertain tourism demand in Hawaii : risk in a computable general equilibrium model

Pratt, Stephen A. January 2009 (has links)
This thesis estimates the economic impact of uncertain tourism demand in Hawaii. It does this by incorporating risk into a Computable General Equilibrium (CGE) model. CGE models have been used to investigate a wide range of policy issues. To date, none have investigated how uncertainty regarding future tourism demand impacts on an economy. The context in which this research is set is the US State of Hawaii. The economy of Hawaii is heavily dependent on tourism as a source of income and a generator of employment. Shocks originating outside of Hawaii have resulted in sharp decreases in visitor arrivals to Hawaii. Yet, these events and the risks associated with future possible shocks to an economy is something that needs to be factored in when planning for the future hence the need to understand what type of impacts uncertain tourism demand will have on the economy. This thesis develops a new method for incorporating uncertainty within an applied economic model. The method involves incorporating uncertainty through different states of the world or paths that the economy may take. The risk then is that one or more of the paths may experience an external shock, which in the example used is a downturn in tourism demand. This thesis then adds to the body of knowledge methodologically. The multi-sector forward-looking CGE model with risk shows the impact of uncertainty on the economy. The results show that, where there is an asymmetric shock, the possibility of a future tourism demand shock creates a welfare loss. The welfare gains along the non-shocked path are a result of household’s risk aversion and their substituting resources away from the shocked path. The difference in the monetary values of the welfare on the different paths can be interpreted as the ‘price’ of the risk. It is the price households would pay to remove the possibility of the tourism shock. Therefore, this research was able to quantify the monetary value of the risk. Several government policy decisions, such as the imposition of a tourism tax, are simulated to mitigate the impact of the uncertainty.
8

An investigation of braided river dynamics using a new numerical modelling approach

Cudden, Judith Rose January 2002 (has links)
Braided Cascade has been developed from Cascade (Braun and Sambridge, (1997)), a long-term (dt = 100 years) numerical model that simulates long-term landscape evolution. Herein it has been modified and applied to relatively short term process modelling of the evolution of complex river topography, discharge and sediment load of braided rivers. Braided Cascade is synthesist in spirit, there is no detailed hydrodynamic component to the model, a realistic simplification at the time scales considered. The major advantage of the model is the incorporation of an irregular time-varying grid using a triangulated irregular network (TIN) to represent a terrain surface. Advantages of using TINs include the ability to solve problems with non-rectangular geometeries and/or boundary conditions and the ability of river segments to form in all directions. The model routes water from node to node based on the local topographic slope. Sediment transport depends on the local stream power. Nodal elevation changes after each iteration according to the difference between the amount of sediment entering and leaving the node. Model output includes spatial and temporal (at one point) water discharge, bedload sediment transport, as well as maps of channel networks, erosion and deposition throughout the reach. Sensitivity analysis indicated that the most significant parameters for braiding are erosion length scale, splitting ratios and the allowance of the model to deposit sediment. Therefore an imbalance in the amount of sediment the river is carrying and the carrying capacity AND a reworking of the deposits is needed for a braided network to form. Sediment output from model runs indicate that the similarities between model data and other data sets are weak and all runs tended to reach static equilibrium. Braided Cascade therefore failed to adequately reproduce realistic data sets. It was found that the differences between model results and the flume data indicate that the model does not always match the physical systems as closely as physical systems match each other.
9

Does geography matter? an empirical investigation into neighbourhood, peer effects and electricity consumption

Weinhardt, Felix Julian January 2012 (has links)
This thesis consists of four distinct projects which sit at the crossroad between Labour, Education and Environmental Economics. The underlying and unifying theme is the examination of social and geographical inequalities using applied econometrics. In the first project, I estimate the effect of moving into a deprived high-density social housing neighbourhood on the educational attainments of teenagers in England. I exploit the timing of moving, which can be taken as exogenous because of long waiting lists for social housing in high-demand areas, to avoid the usual sorting problems. Using this strategy, I find no evidence for negative effects. The second project investigates the effect of neighbours' characteristics and prior achievements on teenagers' educational outcomes. The study relies on mover-induced variation in neighbourhood quality, whilst controlling for general gentrification trends and other unobservables. The results provide little evidence for significant effects on pupil test score progression. The third project looks at the size, significance and heterogeneity of ability peer effects in secondary schools in England. The methodological innovation is to identify ability peer effects using within-pupil-across-subject variation in students' test scores and peer prior achievements. The chapter shows that it is the low- and high-achievers, who account for most or all of the effect of average peer quality on the educational outcomes of other pupils and that this effect varies across genders. The final project presents -to the best of my knowledge- the first nationwide empirical assessment of residential electricity use in response to the timing of daylight for the US. Employing Geographical Information Systems (GIS), I calculate the solar times of sunrise and sunset for all locations in mainland US and show that two distinct sources of geographical variation can be used to estimate county-level responses in residential electricity consumption. Using both approaches I find that early sunrise is associated with lower residential electricity use in the North, but higher consumption in the South. This is a novel finding with potentially significant policy implications and I offer some suggestions about how future research should examine the behavioural channels that could cause these results.
10

Nationalism and tourist-host relationships : a case study of Bala, North Wales

Griffiths, Ingrid A. January 2011 (has links)
Within the domain of tourism, tourist-host relationships are dynamic and complex. The nature of interaction between tourist and host potentially renders a destination more or less desirable to tourists and this, in turn, may impact upon the development and promotion of tourism for that destination. In particular, differences between tourists and hosts will influence the kind of relationship that emerges at the points of contact between them. In ‘intra-national’ settings, where tourists from one country interact with hosts from another, such differences will inevitably be in evidence. Thus, understanding the relevance of nationalism to tourist-host relationships is fundamental to the management of tourism in these contexts. To date, however, little academic attention has been paid to nationalistic determinants of tourist-host encounters. The purpose of this thesis is to address this gap in the literature. Critically exploring the influences of nationalism within tourist-hosts relationships, it focuses specifically on the case of Bala, a small community and tourist destination in North Wales, identifying and appraising the extent and implications of nationalism on the relationship between English tourists and Welsh hosts. Utilising Q method, a technique designed for the systematic study of subjectivity, the research seeks to elicit English tourists’ and Welsh hosts’ subjectivities concerning nationalism, and by association, uncover subjectivities towards national identities, culture and tourism. It reveals that, fundamentally, nationalism does influence the nature of the relationship between English tourists and Welsh hosts in a number of ways, particularly with respect to nationalistic understanding, perceptions of self in relation to others and perception of others. However, the research also indicates that the nature of relationships between tourists and hosts is essentially an ongoing social process which, given time, will reach an organic equilibrium condition. As a consequence, tourism policy and process interventions to manage tourist-host relationships are considered futile within ‘intra-national’ environments.

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