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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

The suitability of WiFi infrastructure for occupancy sensing / Melanie Delport

Delport, Melanie January 2014 (has links)
The focus of this study was to investigate an alternative and more cost effective solution for occupancy sensing in commercial office buildings. The intended purpose of this solution is to aid in efficient energy management. The main requirements were that the proposed solution made use of existing infrastructure only, and provided a means to focus on occupant location. This research was undertaken due to current solutions making use of custom occupancy sensors that are relatively costly and troublesome to implement. These solutions focus mainly on monitoring environmental changes, and not the physical locations of the occupants themselves. Furthermore, current occupancy sensing solutions are unable to provide proximity and timing information that indicate how far an occupant is located from a specific area, or how long the occupant resided there. The research question was answered by conducting a proof of concept study with data simulated in the OMNeT++ environment in conjunction with the MiXiM framework for wireless networks. The proposed solution investigated the fidelity of existing WiFi infrastructure for occupancy sensing, this entailed the creation of a Virtual Occupancy Sensor (VOS) that implemented RSS-based localisation for an occupant’s WiFi devices. Localisation was implemented with three different location estimation techniques; these were trilateration, constrained nearest neighbour RF mapping and unconstrained nearest neighbour RF mapping. The obtained positioning data was interpreted by a developed intelligent agent that was able to transform this regular position data into relevant occupancy information. This information included a distance from office measurement and an occupancy result that can be interpreted by existing energy management systems. The accuracy and operational behaviour of the developed VOS were tested with various scenarios. Sensitivity analysis and extreme condition testing were also conducted. Results showed that the constrained nearest neighbour RF mapping approach is the most accurate, and is best suited for occupancy determination. The created VOS system can function correctly with various tested sensitivities and device loads. Furthermore results indicated that the VOS is very accurate in determining room level occupancy although the accuracy of the position coordinate estimations fluctuated considerably. The operational behaviour of the VOS could be validated for all investigated scenarios. It was determined that the developed VOS can be deemed fit for its intended purpose, and is able to give indication to occupant proximity and movement timing. The conducted research confirmed the fidelity of WiFi infrastructure for occupancy sensing, and that the developed VOS can be considered a viable and cost effective alternative to current occupancy sensing solutions. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2014
92

Factors affecting the detectability and distribution of the North American river otter

Shardlow, Mackenzie Rose January 1900 (has links)
Master of Science / Department of Biology / Craig Paukert / The North American river otter (Lontra canadensis) was extirpated throughout much of its range but is now recovering in many areas. Consequently, there is a need to determine river otter occupancy and habitat associations. We conducted sign surveys from January to April 2008 and 2009 in eastern Kansas to assess how local- and landscape-scale habitat affects river otter occupancy and how survey methods and habitat affect the detectability of river otter sign. Multiple observers surveyed 3-9 400-m stretches of stream and reservoir shorelines for 110 randomly-selected sites and measured local-scale (within a 100 m buffer of site) habitat variables (e.g., stream order, sinuosity, proportion of land cover types) and landscape-scale (Hydrological Unit Code 14 watershed) habitat variables (e.g., road density, shoreline diversity, proportion of land cover types). We then modeled occupancy and detection probability as a function of these covariates using Program PRESENCE. The overall probability of occupancy accounting for detection probability was 0.329. The best-fitting model indicated river otter occupancy increased with the proportion of woodland cover and decreased with the proportion of cropland and grassland cover at the local scale. The best-fitting model also indicated occupancy increased with decreased shoreline diversity, waterbody density, and stream density at the landscape scale, possibly because of the influence of large reservoirs in the watershed. Occupancy was not affected by land cover or human disturbance at the landscape scale, perhaps due to our relatively homogeneous study area or because river otters are habitat generalists. Detection probability for 400-m surveys was highest in mud substrates (p = 0.600) and lowest in snow (p = 0.180) and litter substrates (p = 0.267). Detection probability for scat was more than double that for tracks, and detection probabilities were 17-64% lower for novice observers than experienced observers. Detection probability also increased with survey length. Sign surveys are a useful technique for monitoring many species, including river otters, and accounting for detection probability will improve estimation of occupancy. Furthermore, understanding the ecological factors and the scale important to river otter occurrence will be useful in identifying areas for restoration and management efforts.
93

FQPSK VERSUS PCM/FM FOR AERONAUTICAL TELEMETRY APPLICATIONS; SPECTRAL OCCUPANCY AND BIT ERROR PROBABILITY COMPARISONS

Law, Eugene, Feher, Kamilo 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The aeronautical telemetry community is investigating alternative modulation methods to the commonly used non-return-to-zero (NRZ) pulse code modulation (PCM)/frequency modulation (FM). This paper outlines the important characteristics being investigated. Measured data comparing the spectral occupancy and bit error probability (BEP) performance of PCM/FM with that of a prototype constant envelope Feher’s quadrature phase shift keying (FQPSK) modulator and demodulator will also be presented. Measured results in several radio frequency bands demonstrate that the 99.99% and -60 dBc bandwidths of filtered FQPSK are only approximately one-half of the corresponding bandwidths of optimized PCM/FM even when the signal is non-linearly amplified. The signal energy per bit to noise power spectral density (E /N ) required for a BEP of 1×10 b 0 -5 for non-optimized FQPSK was approximately 12 dB which is approximately the same as limiter discriminator detected PCM/FM.
94

ARTM TIER II WAVEFORM PERFORMANCE

Temple, Kip 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / One of the charters of the Advanced Range Telemetry (ARTM) program was to develop more spectrally efficient waveforms while trying to maintain similar performance to the legacy waveform, Pulse Code Modulation/Frequency Modulation (PCM/FM). The first step toward this goal was the ARTM Tier I family of waveforms which include Feher patented, quadrature phase shift keying, -B version (FQSPKB) and shaped offset quadrature phase shift keying, Telemetry Group version (SOQPSK-TG). The final step was development of Tier II, an even more spectrally efficient waveform, multi-h Continuous Phase Modulation (CPM). This paper characterizes the performance of this waveform when applied in an airborne telemetry environment and, where appropriate, comparisons are made with existing Tier 0 and Tier I waveforms. The benefits, drawbacks, and trade-offs when applying this waveform in an airborne environment will also be discussed.
95

Sustainable schools : beyond measure?

Roberts, Michael January 2014 (has links)
This PhD research project has examined four newly built secondary schools in Leicester, England that were procured through the UK Government’s Building Schools for the Future (BSF) programme (2003-2010). The research strategy has adopted a mixed-methods approach using a range of quantitative and qualitative data. The principle aim was to establish a theoretical framework for Sustainable Development which could then help to shape the analysis. Five specific dimensions were identified as a result of an extensive literature review (Education [A], Community [B], Environment [C], Technology [D] and Economics [E]). It was also important to consider the dynamic nature of a school in relation to the study’s overarching question; ‘Sustainable Schools; Beyond Measure?’ In this regard, a “systems” approach was selected, which in turn led to the identification of three further levels of analysis (Inputs [1], Processes [2] and Outcomes [3]). Five objectives were then identified, helping to instruct the direction of the research activities. Firstly, the BSF procurement mechanism had to identify a private sector partner to rebuild the 16 secondary schools in Leicester over a 10 year period. This was time consuming and did not include energy efficiency as part of the selection process. Secondly, the commissioning of the four phase one buildings prior to occupancy was not sufficiently thorough. As a result, multiple operational problems were encountered post-occupancy by the Facility Management (FM) Provider. Thirdly, when the utility data was examined, the schools were not performing efficiently around their schedule of activities. When the Building Management Systems (BMS) were subsequently re-commissioned, timer settings were adjusted, resulting in substantial carbon and energy savings. Fourthly, when the staff completed an occupancy satisfaction survey, the results identified numerous comfort problems which could be linked to the heating, ventilation and air-conditioning systems (HVAC). Finally, when the researcher looked back at the past 10 years of educational statistics (2002-2012), it was clear how attainment, based on GCSE results, had dramatically improved following the move into the new buildings in September 2009. In order to draw out new insights from this wide spectrum of data, a matrix was developed, helping to organise the information in a systematic way. More generally, it is hoped this approach will promote a more intricate understanding about the way Sustainable Development can be integrated into future procurement mechanisms, building regulations and education policy.
96

Study of the Higgs boson decay H → ZZ(∗) → 4ℓ and inner detector performance studies with the ATLAS experiment

Selbach, Karoline Elfriede January 2014 (has links)
The Higgs mechanism is the last piece of the SM to be discovered which is responsible for giving mass to the electroweak W± and Z bosons. Experimental evidence for the Higgs boson is therefore important and is currently explored at the Large Hadron Collider (LHC) at CERN. The ATLAS experiment (A Toroidal LHC ApparatuS) is analysing a wide range of physics processes from collisions produced by the LHC at a centre-of-mass energy of 7-8TeV and a peak luminosity of 7.73×10³³ cm−2s−1. This thesis concentrates on the discovery and mass measurement of the Higgs boson. The analysis using the H → ZZ(∗) → 4ℓ channel is presented, where ℓ denotes electrons or muons. Statistical methods with non-parametric models are successfully cross-checked with parametric models. The per-event errors studied to improve the mass determination decreases the total mass uncertainty by 9%. The other main focus is the performance of the initial, and possible upgraded, layouts of the ATLAS inner detector. The silicon cluster size, channel occupancy and track separation in jets are analysed for a detailed understanding of the inner detector. The inner detector is exposed to high particle fluxes and is crucial for tracking and vertexing. The simulation of the detector performance is improved by adjusting the cross talk of adjacent hit pixels and the Lorentz Angle in the digitisation. To improve the ATLAS detector for upgrade conditions, the performance is studied with pile-up of up to 200. Several possible layout configurations were considered before converging on the baseline one used for the Letter of Intent. This includes increased granularity in the Pixel and SCT and additional silicon detector layers. This layout was validated to accomplish the design target of an occupancy < 1% throughout the whole inner detector. The H → ZZ(∗) → 4ℓ analysis benefits from the excellent momentum resolution, particularly for leptons down to pT = 6GeV. The current inner detector is designed to provide momentum measurements of low pT charged tracks with resolution of σpT /pT = 0.05% pT ⊕ 1% over a range of |η| < 2.5. The discovery of a new particle in July 2012 which is compatible with the Standard model Higgs boson included the 3.6σ excess of events observed in the H → ZZ(∗) → 4ℓ channel at 125GeV. The per-event error was studied using a narrow mass range, concentrated around the signal peak (110GeV< mH < 150GeV). The error on the four-lepton invariant mass is derived and its probability density function (pdf) is multiplied by the conditional pdf of the four-lepton invariant mass given the error. Applying a systematics model dependent on the true mass of the discovered particle, the new fitting machinery was developed to exploit additional statistical methods for the mass measurement resulting in a discovery with 6.6σ at mH = 124.3+0.6−0.5(stat)+0.5−0.3(syst)GeV and μ = 1.7±0.5 using the full 2011 and 2012 datasets.
97

Spatiotemporal Variation in Occupancy and Productivity of Grebes in Prairie Canada: Estimation and Conservation Applications

2012 September 1900 (has links)
Wetlands of the Prairie Pothole Region (PPR) provide important breeding habitat for greater than 30 species of waterbirds. Approximately 70% of PPR wetlands have been lost since European settlement and remaining wetlands are subjected to frequent degradation, primarily due to agricultural activities. Horned grebes (Podiceps auritus) are experiencing long-term population declines and are listed as a species of Special Concern in Canada. Because there is virtually no information on the status and trends of pied-billed grebes (Podilymbus podicep) this species is also of considerable conservation concern. Grebes are recorded on the Waterfowl Breeding Population and Habitat Surveys (WBPHS) conducted annually in May by the Canadian Wildlife Service; however, how accurately these counts reflect actual abundance has been unknown. Using a repeated counts method in 2010 and 2011, estimates of detection probabilities averaged 0.48 and 0.18 for horned and pied-billed grebes, respectively. These results suggest that WBPHS ground surveys may be used as an efficient and effective management tool for monitoring horned grebe abundances. However, low detection rates for pied-billed grebes lend little support for including the species in future monitoring efforts using the WBPHS. I recommend that the Canadian Wildlife Service consider implementing standardized ground survey methods to facilitate annual monitoring of horned grebe abundances. Marshbird research has focused primarily on breeding habitat use or selection but has seldom examined how productivity is related to wetland characteristics. Understanding processes that affect distribution patterns and productivity of grebes could provide insights into actions needed to achieve conservation goals. Therefore, occupancy of wetlands by breeding and brood-rearing horned and pied-billed grebes was evaluated on 6-7 study sites (5.8-11.6 km2) in south-central Saskatchewan, 2010 and 2011, and related to wetland and upland habitat features. Wetland occupancy by grebes was influenced by interspecific competition as well as local and landscape-level wetland features. Horned and pied-billed grebes rarely co-occurred on smaller (≤4 ha) semi-permanent and permanent wetlands. At the wetland level, horned grebe occupancy and productivity were highly correlated with the amount of emergent vegetation, whereas wetland area alone was a better predictor of adult pied-billed grebe occupancy and productivity. At a landscape level, the number of semi-permanent, permanent, and artificial wetlands on each study site was an important predictor of breeding and brood-rearing wetland occupancy probability for horned grebes in 2010 and for pied-billed grebes in both years. However, breeding horned grebe occupancy probability and productivity were higher in low wetland density landscapes in 2011. Horned grebes may be opportunistic, exploiting more of the available wetland habitats in low wetland density landscapes during years of above-average water conditions. Conservation initiatives for grebes should consider the roles of wetland-specific and landscape-level features while protecting semi-permanent and permanent wetlands in landscapes characterized by both high and low wetland densities.
98

Transforming neighbourhoods : an exploration of the neighbourhood management process in Ilfracombe, Devon

Ward, Kim January 2011 (has links)
The neighbourhood became one of the key sites for urban policy development during the previous New Labour government, and Neighbourhood Management Pathfinders were amongst their final strategies to combat “the most difficult problems faced by deprived neighbourhoods” (SEU 2000:5). This thesis explores the process of neighbourhood management in the coastal town of Ilfracombe, Devon. Ilfracombe features the characteristics of decline found in a number of coastal towns across the country, and suffers from high levels of deprivation (House of Commons Report 2006). Consequently, the neighbourhood management pathfinder ‘Transform’ was deployed in Ilfracombe in an attempt to address high deprivation. This thesis uses empirical findings collected through interviews and focus groups to examine the process of ‘Transform’, from its conception to its practical operation. It specifically considers the ‘voices’ of residents whose opinions and experiences, as targets of neighbourhood intervention are not always sufficiently documented within policy narratives. Consequently, the thesis unravels the process of neighbourhood management through findings generated by qualitative research ‘on the ground’. These are then examined through the lens of governmentality, allowing the methods, practice and outcomes of government, to be unpacked through a presentation of my empirical findings (Foucault 1991). These examinations take a particular interest in notions of community engagement and participation, partnership working, and the process of social exclusion. Here, partnership is demonstrated to be a tentative and fragile process underlined by local histories and differing temporal frameworks for action. But, this research also demonstrates that joint working can be improved through neighbourhood management which widens routes of communication to officers ‘on the ground’. However, what this thesis hopes to demonstrate most strongly is the continuing depth of problems felt by residents in Ilfracombe and that the process of ‘inclusion’ through paid work and ‘active’ citizenship, underlined in Labour’s neighbourhood renewal strategies, is not tackling some of the main problems of ‘deprived’ neighbourhoods, as experienced by the residents themselves.
99

Effects of landscape change on corsac foxes in Mongolia

Lkhagvasuren, Myagmarjav 01 January 2015 (has links)
Landscape change affects the distribution of wildlife and represents a conservation concern, especially in Asia, which is experiencing rapid development. In Mongolia, mining, livestock grazing, infrastructure development and climate change represent major drivers of change that will impact habitats and few tools exist to predict how wildlife will respond. I examined the impacts of landscape change on the corsac fox (Vulpes corsac) in a steppe region of Mongolia. The corsac fox occurs widely throughout northern Asia, but has experienced declines in many regions and remains one the least studied canids. I addressed two questions: 1) how do common features of a landscape, such as habitats, topography, herder camps, and roads, shape the distribution of the species? and 2) how will changes in those features affect distribution in the future? I collected locations of foxes from radio-collared animals, scat surveys, and opportunistic sightings in Ikh Nart Nature Reserve, then used maximum likelihood methods and model selection techniques to develop a model that predicts occupancy probability. I then applied the model to simulations of landscape change. I collected 1,965 locations and examined 19 candidate models. The model with the most support indicated that occupancy is best described by the additive combination of shrublands, open plains, tall grasslands, and rocky habitat. Models with other covariates (camps, roads, and ruggedness) had little support. A Receiver-Operator-Characteristic plot of model performance had an Area Under the Curve of 77%, indicating that the model predicted occupancy better than expected by chance. Average occupancy across the reserve was 22% under current conditions. Incremental reductions in shrubland, open plains, and tall vegetation resulted in occupancy declines with average occupancy being 7%, 13%, and 14%, respectively, when these habitats were completely absent. The loss of all three habitats due to the desertification of the landscape through climate change resulted in an average occupancy of 7%. The results provide the first model of corsac fox occupancy, which can be used to quantitatively examine distribution and impacts of change in other parts of the species' range. In Ikh Nart, results suggest that climate change poses the greatest threat to the species as it is expected to reduce high quality habitats and confine corsac foxes to areas with high competition from red foxes.
100

The Village of River Ranch: A Post Occupancy Evaluation of a Traditional Neighborhood Development in Lafayette, Louisiana

Tomlinson, Elizabeth A. 15 December 2007 (has links)
The proponents of New Urbanism claim the neighborhoods they design, called Traditional Neighborhood Developments (TNDs), promote community, sense of place, physical health, and environmental sustainability. Critics assert that community is stressed at the expense of individuality, that design unity has become rigid uniformity, and that the neighborhoods are orchestrated and do not reflect real life. This thesis, a post occupancy evaluation (POE), examines how one TND works for its residents and whether it accomplishes the goals of the architect/planner. An additional, essential purpose of this POE is to serve the "feed-forward" role of informing future neighborhood planning projects. The Village of River Ranch in Lafayette, Louisiana is the site of my research. Utilization of multiple research methods (survey, interviews, naturalistic observations) offered opportunities for triangulation and the ability to produce a more comprehensive analysis.

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