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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.
91

Towards understandings of visitor experiences and practices that shape new meanings of place at National Trust sites

Cope, G. January 2014 (has links)
The National Trust face a new set of challenges in recent years; as one of the most influential heritage bodies in the UK, it is responsible for the preservation and protection of a large number of diverse sites from historic buildings to woodland. Yet this is set against a backdrop of complex set of challenges: creating an active dialogue with those who visit its sites and other stakeholders, such as the local community; ensuring their sites are preserved while, at the same time, encouraging access; on-going climate change and environmental risks; changing cultural, social and economic frameworks. The aim for the National Trust is to better understand how places might be managed differently in the light of these challenges. This research builds on existing quantitative research conducted by the National Trust by examining how the engagement, embodiment and practice of visitors, staff and volunteers at National Trust sites informs a sense of place. The research employs a mixed method approach using qualitative ethnographic techniques. The methods of video and audio capture were used to explore and engage with the highly complex processes practiced at the sites and capture the non-verbal, pre cognitive and emotive ways in which people engage with site. From this insight, the research makes a conceptual contribution to knowledge by examining how site based practice informs emotional engagement and affect of place and how this experience produces a sense of place for people within National Trust sites. Traditionally, the National Trust has put the physical aspects of a site at the heart of the visitor experience, whereas my research serves to demonstrate how an individual makes sense of a place through their own experiences, memories, cultural identity and uses these lenses to understand the world and their own identity. Furthermore, the research demonstrates that places are not fixed concepts but formed in an on-going, iterative way where multiple, sometimes competing, memories, emotions and affects are produced and that a place making is messy, interwoven with multiple, sometimes competing rhythms, emotions, affects and how this sense of place gets carried over time and space. The contribution that this research makes, therefore, is in extending the insights into how place can change people to how people change place within the context of National Trust sites.
92

Remote sensing of spatiotemporal phytoplankton dynamics of the optically complex Lake Balaton

Palmer, Stephanie Catherine Jane January 2015 (has links)
This thesis explores the use of remote sensing to measure the phytoplankton biomass of Lake Balaton, Hungary via the proxy pigment, chlorophyll-a (chl-a). Several scales of spatial and temporal variability are considered, using a ten year time series of Medium Resolution Imaging Spectrometer (MERIS) satellite imagery, ship-mounted Light Detection and Ranging (LiDAR), and water sampling and laboratory measurements from punctual and ongoing campaigns. Existing remote sensing methods are adapted to Lake Balaton for the first time, and novel directions are demonstrated which may be applied to other lakes in the future. Several chl-a retrieval algorithms applied to archive MERIS data are calibrated and validated using an extensive dataset of coinciding in situ measurements and results from each are compared. The application of two atmospheric correction algorithms is also validated and their influence on chl-a retrieval is considered in comparison with the use of un- atmospherically corrected, top-of-Atmosphere (TOA) data. The fluorescence line height (FLH) algorithm applied to TOA MERIS data is found to accurately and robustly retrieve Lake Balaton chl-a (R2 = 0.87; RMSE = 4.19 mg m-3), particularly during high biomass bloom events (chl-a ≥ 10 mg m-3). This algorithm is then applied to the full MERIS archive (2002-2012), resulting chl-a time series are smoothed at the pixel level, and phytoplankton phenology metrics are extracted and mapped. Phenology metric mapping in lakes using MERIS remote sensing is demonstrated and significant spatiotemporal variability in bloom metrics is apparent. Laboratory tank and in situ ship-mounted Ultraviolet Fluorescence LiDAR (UFL) measurements indicate another novel direction for lake remote sensing. Chl-a, as well as total suspended matter (TSM) and coloured dissolved organic matter (CDOM), were measured and cyanobacteria was distinguished from chlorophyta via fluorescence emission spectra. The feasibility of retrieving accurate and quantitative information on Lake Balaton phytoplankton biomass dynamics through the use of remote sensing techniques is confirmed, and the resulting added value for both science and management is highlighted.
93

Estimating population surfaces in areas where actual distributions are unknown : dasymetric mapping and pycnophylactic interpolation across different spatial scales

Jega, Idris Mohammed January 2015 (has links)
Spatially distributed estimates of population provide commonly used demand surfaces in support of spatial planning. In many countries, spatially detailed population summaries are not available. For such cases a number of interpolation methods have been proposed to redistribute summary population totals over small areas. Population allocations to small areas are commonly validated by comparing the estimates with some known values for those areas. In areas where spatially detailed estimates of the population do not exist, that is where the actual population in small areas is unknown, such as Nigeria validation is problematic. This research explores different interpolation methods applied at different scales in areas where the actual population distribution is known and where validation is possible. It then applies the parameters developed from these results to areas where the distribution is unknown. The binary dasymetric method using land cover data derived from a classified 30m spatial resolution satellite imagery as the ancillary data input and with disaggregation over 30m support grids, was found to provide the best target zones estimates of the population. The demand surfaces were then used to evaluate current health facility locations and then to suggest alternative spatial arrangements for health centres in Port-Harcourt, Nigeria. The average distance from each demand point to the nearest healthcare centre was found to be 1204m. When alternative locations for the current health centres were identified, the results suggest 13 service provision points would provide almost the same demand coverage as the 17 current PHCCs. This research develops methods that can be used to support informed decision making in spatial planning and policy development.
94

The impact of alternative distance measures and temporal variation in demand on location-allocation decisions

Chukwusa, Emeka January 2014 (has links)
The aim of the study was to explore the impact of spatio-temporal variations in demand and alternative-based GIS measures on location–allocation. Location-allocation models are mathematical formulations that seek to optimise facility locations (supply) in relation to the spatial distribution of demand and transport networks. However, there are a number of shortcomings to many location-allocation analyses applied to spatial planning. First, in most analyses the demands that are used as inputs to the models are static. Second, location-allocation models usually fail to incorporate demand trends and most analyses only use the most recent demand estimates. Third, distances separating supply and demand locations have been modelled as 3D, by incorporating variations in elevation or as 2D by assuming that the earth's surface is a continuous plane. This thesis addresses these shortcomings by investigating the impact of these factors on location-allocation decisions making based on different case studies. The first analysis explored the impact of short-term spatio-temporal variations through a case study of EMS location planning in Leicestershire. This was achieved by comparing a residential-based location model, which assumes that demand is static with an alternative location model – the travel-to-work model that incorporates dynamic changes in demand due to journey-to-work. The results of the analysis showed clear differences in both approach, in terms of selected locations, demand allocated to selected locations, Average Weighted Distance (AWD) and demand coverage. In the second analysis, the impact of the long-term spatio-temporal variations in demand was explored through a case study of deriving optimal locations for outreach clinics in Leicester. A trend-weighted approach that incorporates the trajectories of changes in demand was compared with the Non-trend weighted model - a traditional approach that ignores the changing demand trend. The results from the comparative analysis indicated that neglecting demand trend over time, consistently underestimates AWD to selected outreach clinic. This finding suggests that current and future access to outreach clinic may be underestimated, when trends in demand are ignored. Finally, the third analysis compared 2D and 3D distances based on a case study of finding optimal locations for EMS in the hilly areas of South Yorkshire and Sheffield. The results indicated that location-allocation results derived from 3D distance measures are not significantly different from results derived from 2D distance measures. Overall, the finding from the comparative analysis using simulated elevation surfaces, demonstrate that other factors such demand weight distributions and distribution of demand and supply locations influence the outcome of the P-median model. The study concluded that 3D distance is more suited for vehicle routing and allocation problems and siting of Automatic External Defiribilators (AEDs) in building interiors and therefore may not be suitable for location planning in the outdoor environment.
95

A modified analytical hierarchy process method to select sites for groundwater recharge in Jordan

Al-shabeeb, Abdel Rahman Rakad January 2015 (has links)
The aim of this study was to identify potential sites for groundwater recharge in the Azraq basin in Jordan. Several research questions were answered in this study including how to utilize the views and opinions of multiple experts in the field of groundwater recharge within a spatial analysis framework to identify the suitable sites for groundwater recharge in the study area and check the consistency in these opinions and their spatial representation. The Analytic Hierarchy Process (AHP) was modified in a novel approach to identify the potential sites for the groundwater recharge in the study area. First, the physical criteria that affect the groundwater recharge were identified based on an extensive literature review. Seventeen experts were then asked to evaluate the importance of each criterion. The consistency ratio between the experts opinions were evaluated using the pairwise comparison method and a final weight was computed for each criterion. A groundwater recharge suitability map was then generated following the weighted linear combination (WLC) method. The sites that are not suitable for groundwater recharge within the study area were identified and eliminated following the Boolean method, and a final groundwater recharge suitability map was generated. The outcome of the GIS analysis of this study was evaluated against field investigations carried out in the study area. Time Domain Electromagnetic (TDEM) and Soil Texture Analysis were used on sixteen locations distributed in eight sites within the study area. The results acquired by the field investigation agreed well with the GIS acquired results. The knowledge generated by this analysis may provide information on potential recharge zones. Finally, the findings of this research can be used to assist in the efficient planning of the groundwater management to ensure a sustainable development of the groundwater in Jordan and in other areas suffering from water shortages.
96

Improving population estimates using remotely sensed and ordnance survey datasets

Kose, Mustafa January 2015 (has links)
The accuracy of population data is of critical importance in supporting the design of public and private-sector facilities. Demographic data are usually supplied by national census organisations at pre-defined census output levels. However, demographic datasets may be required at user-defined spatial units that can be different from the initial census output levels. A number of population estimation techniques have been developed to address these problems. This thesis is one of those attempts aimed at improving small-area population estimates by using spatial disaggregation models of: 1) binary mapping, 2) address-weighted dasymetric and 3) volumetric estimation models. These interpolation approaches employs high-resolution aerial imagery, LiDAR-derived building volumes and the integration of building address points and occupancy information sourced from the Ordnance Survey © and Airbus Defence and Space. Census wards and output areas were used as source zones and target zones respectively, to estimate population counts in Leicester City and the Borough of Kensington and Chelsea, London where the population is distributed both horizontally and vertically. The predicted population values were compared with 2011 census of actual population datasets. Each method employed in the study generated different population estimates depending on their assumptions and required datasets. The accuracy appears to be mainly influenced by the type and quality of the ancillary datasets and also the interpolation method adopted. Based on the disaggregation models adopted in this study, the address-weighted model produced the best population estimates with Root Mean Square Error (RMSE) value of 0.64 and R2 score of 0.998 for the City of Leicester and RMSE value of 0.236 and R2 score of 0.997 for the Borough of Kensington and Chelsea. This estimation is an indication that building address point datasets that contain information on occupancy can be used within Dasymetric mapping approaches to improve population estimates over a range of urban areas.
97

Remote sensing-based mapping and modelling of salt marsh habitats based on optical, LiDAR and SAR data

van Beijma, Sybrand Jucke January 2015 (has links)
There is much interest in the ability of Remote Sensing (RS) technologies for mapping natural environments. Meanwhile, coastal zones need monitoring in order to find a balance between human use and sustainable functioning of coastal zone ecosystems. This research explores methods for characterising coastal salt marsh zone habitats using multi-source RS data, focussing on under-exploited Synthetic Aperture Radar (SAR) remote sensing data, thereby providing additional information in support of the mapping of natural habitats in coastal zones. This research examined the use of quad-polarimetric airborne S-band and X-band SAR data, in conjunction with optical and LiDAR RS data variables, for assessment of environmental parameters, mapping and modelling of salt marsh habitats in a research area set in the Llanrhidian salt marshes in Wales. In the first analysis it was researched how SAR descriptors (backscatter intensity and polarimetric decomposition variables) were affected by salt marsh environmental and botanical factors. It was found that SAR backscatter from the most seaward pioneer zone of the salt marsh was most affected by soil moisture variations. Differences in botanical structure caused variations in SAR backscatter mechanisms active in different habitats. In the second analysis habitat mapping was carried out with optical, LiDAR and SAR variables, with the supervised classifiers Support Vector Machine (SVM) and Random Forest (RF). With these classifiers accurate salt marsh habitat maps were produced, the most accurate classification achieved was 78.20% with RF based on all available RS variables. The last research experiment involved multivariate regression analysis of correlations between RS variables and biophysical parameters vegetation cover, height and volume and showed that multivariate SVM regression was the most accurate technique for all three biophysical parameters. This research indicated that SAR is complementary to optical and LiDAR data for ecological mapping and therefore recommended to be included in similar ecological studies.
98

Assessment of physiological status and spatial distribution of emergent macrophytes based on imaging spectroscopy

Stratoulias, Dimitris January 2015 (has links)
Wetlands are ecosystems encountered at the land-water ecotone and hence inheriting rich complexity and biodiversity. Emergent macrophytes are a prime example of this variability manifested by the co-occurrence of vegetation associations at a very fine spatial level. From 1960s onwards an abrupt deterioration of reed beds in Europe has been systematically observed and denoted as the ‘reed die-back’. Since then, earth observation has been utilized mainly to map the extent of reed beds based on multispectral information. Hyperspectral remote sensing has frequently been employed in vegetation related studies, however the spectral information content of macrophytes has not been widely investigated. This study focuses on assessing the potential of imaging spectroscopy for assessing the ecophysiology of lake shore vegetation at leaf level and mapping macrophytes species associations from airborne imagery. Concurrently acquired spectroscopic, chlorophyll fluorescence and chlorophyll content information from field samples around Lake Balaton, Hungary are employed to identify spectral regions and propose narrowband indices which can aid the identification of reed ecophysiological status based solely on vegetation spectral characteristics. Macrophyte species as well as Phragmites in different phenological states have concretely separate spectral responses, however stable and die-back reed are not crucially different. Bathymetry regulates consistently the spectral response of Phragmites. Narrow band ratio 493/478 (0.65***) correlates with the ETR, the latter being an indication of the photosynthetic activity of the plant, and hence the vegetation physiological status. Most indices correlating with fluorometric parameters are located in the optical domain. Based on R2 graphs, the ratios 699/527 and 612/516 can be used to estimate Y(II) from AISA hyperspectral data. Estimation of the photophysiological parameters of a reed bed is possible based solely on airborne hyperspectral imagery. Simultaneously acquired airborne AISA Eagle, Hawk and discrete return LiDAR data are combined in order to stress out the potential of each dataset in classifying the reed bed in terms of species associations. An application of SVM on noise-reduced Eagle data, at the chlorophyll and near infrared absorption spectral regions, provides the most concrete results in terms of overall accuracy (89%). SVM outperforms ML and infrared sensors as well as LiDAR data do not improve the categorization of macrophyte classes. While airborne data inherit a superior spectral and spatial resolution, they are difficult to acquire in an operational context. Upcoming satellites will provide imagery with progressively higher spatial and spectral capabilities. A simulation of Sentinel-2 image over a reed bed in a nature protected area indicates the potential of satellite imagery in mapping macrophytes. Main classes can be distinguished, despite the fact that inter-class separability is becoming vague. Given the very large swath of Sentinel-2 (290km) an operational categorization of main macrophytes is foreseen achievable.
99

Synergistic use of airborne hyperspectral and LiDAR data for mapping Mediterranean forest in Portugal

Pandey, Prem Chandra January 2015 (has links)
Forests are the major source of biodiversity and provide natural sources of wood, fodder, gums, resins, and medicines. Forests encounter damage by nature and human factors, which needs to be monitored for all tree species, whether invasion or intentional damage. This study focuses on the classification of an open tall stand coastal surrounding site for the mapping and classification of tree species and ground features using airborne imagery. So, improving the classification and mapping accuracy of forest in surrounding coastal regions is essential for the restoration and management decisions. The first objective of this thesis is to use segmented Principal Component (PC) images to classify the ground features including different tree species and to improve the classification results. More specific goals include (a) Use of hyperspectral images to map and classify the forest region using a segmented PC image, (b) Investigating the gain in mapping accuracy with segmented PC image as opposed to hyperspectral imagery alone. The second objective is to assess and investigate the fusion of airborne hyperspectral imagery and LiDAR derived Canopy Height Model for classification and assessing the results. These objectives aim at investigating the gain in mapping accuracy with fusion image as opposed to hyperspectral imagery alone. Thus, overall this study assesses the differences in classification outputs using a data fusion technique, segmented PC image and individual hyperspectral images, which differ in accuracy, in Mediterranean forest. MLC based supervised image classification method provided better accuracy (96.3%) with segmented PC images, (~92.9%) with the fusion of CHM and hyperspectral images than with hyperspectral image alone (89.6% with MLC and 67.5% with SAM). According to my results, CHM and HSI provide better classification and mapping results over extensive areas of forests. The overall accuracy of the classified maps ranged from 67.5 to 96.3% and k coefficient was found between 0.61 and 0.95. Segmented PC and PC fusion techniques provided a significant step to improve the distinction and classification results. Using the above methods, tree species and associated features could be classified and mapped, despite the problem of spectral mixing of different features. In future, more high spatial and spectral resolution images will provide a platform for the incorporation of enhanced characteristics for mapping and classification purposes.
100

Governing through the network

Mohanan, A. January 2015 (has links)
This thesis examines the relationship between the state, computer networks and their relationship to the government of education. It explores the historical development of computer networks and the governmental rationalities of education, in addition to an ethnographic study of practices surrounding computer networks at a secondary school in London. This novel approach has looked at interactions between the materiality of networks, their presence in the discourses of national policies and the practices of its end users. It begins by focussing on an early public data network developed at the National Physical Laboratory called the NPL Network. This experimental network was built using the idea that networks had to be fexible and adaptable to the needs of its end users rather than the interests of computer manufacturers and network operators. It also looks at the effects that computer networks have had on governmental mechanisms used to regulate schools. The thesis argues that the introduction of the National Grid for Learning and the National Pupil Database have been used to intensify practices of performance management and intelligence testing. Finally, it looks at practices within schools that are afforded by networked forms of government. Broadly, the thesis problematises the idea that networked forms of governance are less coercive than the mechanisms they replace. The thesis demonstrates that networks have caused an intensification of power within the education system that has made its mechanisms more efficient whilst saturating its field of operation.

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