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.

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.

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.

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.

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.

No description available.

No description available.

No description available.

No description available.

No description available.