Thesis (M. Arch.)--University of Hong Kong, 2000. / Includes special report study entitled: Lighting : space and material. Includes bibliographical references.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Guensler, Randall; Committee Member: Rodgers, Michael; Committee Member: Ross, Catherine. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Disturbance events can alter habitat properties, leading to species displacement, isolation and/or local extinction. In addition, introduced species have been recognized as a threat to biodiversity of native species. Understanding the interacting impacts of fire on native and introduced wildlife species, and the influence on a native species of competition with an introduced species after ecosystem change is critical. Tree squirrels are indicators of forest health; we used two species to determine thresholds and assess behavioral responses to determine adaption to habitat alterations. We studied native Arizona gray squirrels (Sciurus arizonensis), which are believed to favor riparian habitat, and introduced Abert's squirrels (S. aberti), which prefer open parklike ponderosa pine (Pinus ponderosa) in the Santa Catalina Mountains, Arizona, USA. We examined how native but reportedly declining Arizona gray squirrels and introduced Abert's squirrels use areas within widespread fires that burned the study area in 2002-3. Fires burned in a mosaic pattern of unburned, low, moderate, and high burn severity patches. To determine how fire may affect squirrel habitat and behavior, we examined how fire altered habitat use and occupancy, and used distance sampling to determine squirrel abundance, distribution and use within a mosaic of burn severities. Occupancy and habitat use indicate that introduced Abert's squirrels are better adapted to post-fire conditions whereas native Arizona gray squirrels may be adversely impacted by fire disturbance. Our results suggest that Arizona gray squirrel populations may be locally imperiled due to post-fire habitat alteration and loss exacerbated by competition with Abert's squirrels. Abert's squirrels predominantly occupied unburned ponderosa pine and mixed conifer zones with open understories. In contrast, Arizona gray squirrels were documented at only four sites and primarily occupied unburned to low burn riparian areas with dense understories. Abert's squirrels predominately nest and feed in unburned coniferous areas whereas Arizona gray squirrels nest in unburned to low burn nonconiferous areas. Arizona gray squirrels have a reduced distribution and potentially in decline but only remain at lower elevations on the Santa Catalina Mountains. Fire management and restoration efforts should include examination of the differential impacts of fire on native and invasive species.

Solid State NMR spectroscopy has taken a very prominent place among the many spectroscopic techniques employed for the characterization of clathrate hydrates. Exceptionally high sensitivity of the spectra to the molecular environment and dynamic processes, together with the ability to provide accurate and quantitative data make NMR spectroscopy a highly desirable and versatile approach for studying hydrates. Application of the method to its full capacity, however, requires some extensive instrumental developments to adapt it to the specific experimental requirements of hydrate studies, for example, very low temperatures and high pressures. In this presentation we will give an overview of recent Solid State NMR advances in various areas of hydrate research. Examples will include analysis of the composition and structure of mixed gas hydrates prepared from multi-component mixtures of hydrocarbons, characterization of the natural gas hydrates from different sources, and evaluation of formation conditions and properties of mixed hydrogen hydrates. 13C NMR with Magic Angle Spinning (MAS) at -100C has been the main approach in the first two examples. We will discuss the requirements and the necessary instrumental developments to make the experiments of this type successful. The detailed characterization of mixed hydrogen hydrates required low temperature 1H MAS. Problems of quantification in these experiments will be discussed. We expect that all these recent experimental developments will prompt wider application of Solid State NMR in hydrate research.

Raman spectroscopic observations of the characteristics and dissociation of methane hydrate were carried out on hydrates synthesized in silica sands with particle sizes of 53-75 μm, 90-106 μm, 106-150 μm, and 150-180 μm. The results obtained indicate that methane hydrates formed in silica sands had similar characteristics regarding cage occupancy and hydration number (5.99) to bulk hydrate, indicative of no influence of particle size on hydrate composition. During hydrate dissociation, the change in average intensity ratio of large to small cages were generally consistent with that of bulk hydrate but dropped dramatically after a certain time, and this turning point seems to be related to the particle size of silica sands.

The dedicated gas hydrate coring/drilling program was carried out under National Gas Hydrate Program (NGHP) in four Indian offshore areas (Kerala-Konkan, Krishna- Godavari, Mahanadi and Andman) during 28th April to 19th August, 2006. During NGHP Expedition 01, 2006, total of 39 holes were drilled/cored at 21 sites in these areas. The gas hydrates have been found to be present in large quantities in Indian offshore areas particularly in KG basin. More than 130 confirmed solid gas hydrate samples were recovered during this hydrate coring/drilling program. The laboratory analysis was carried out on the 34 natural gas hydrate samples recovered from offshore India. The gas hydrate characterization was carried out using the microscopic techniques such as Raman, 13C NMR and XRD for its structure, cavity occupancy and hydration number. The gas hydrates occur in grayish green fine sediments, gray medium sands and white volcanic ash as pore-filling hydrate and massive hydrates in fractured shale/clay. The visible massive gas hydrates developed especially at Site NGHP 1-10B, 10C, 10D and 21A in K G area. The structures of the gas hydrates in the studied samples are all sI, with methane as the dominant guest molecule. The occupancy of methane in large cage is almost complete, while it is variable in the small cage (0.75 to 0.99). The hydration number is 6.10 ± 0.15 for most of the hydrates in the samples studied. This paper presents the results of the laboratory analysis on the structural characterization of natural gas hydrates in core samples from offshore India.

Raman spectroscopic measurements of various hydrogen bearing clathrate hydrates have been performed under high (< 1cm-1) and low resolution (>2 cm-1) conditions. Raman bands for hydrogen in most common clathrate hydrate cavities have been assigned. Unlike most clathrate hydrate guests, the general observation is no longer valid that the larger the clathrate cavity in which a guest resides, the lower the vibrational frequency. This is rationalized by the multiple hydrogen occupancies in larger clathrate cavities. Both the roton and vibron bands for hydrogen clathrates illuminate interesting quantum dynamics of the enclathrated hydrogen molecules. At 77K, the progression from ortho to para H2 occurs over a relatively slow time period (days). The para contribution to the roton region of the spectrum exhibits the triplet splitting also observed in solid para H2. The complex vibron region of the Raman spectrum has been interpreted by observing the change in population of these bands with temperature and with isotopic substitution by deuterium. Raman spectra from H2 and D2 hydrates suggest that the occupancy patterns between the two hydrates are analogous. The Raman measurements demonstrate that this is an effective and convenient method to determine the relative occupancy of hydrogen molecules in different clathrate cavities.

In the face of an expanding global human footprint, mammalian carnivores have become vulnerable to the effects of large-scale landscape change. Throughout North America, wide-ranging terrestrial carnivores have experienced significant species declines and range retractions. Understanding the complex and interacting effects of human-caused habitat disturbance on highly mobile species remains an ongoing challenge for ecologists. To address these challenges, studies commonly select a focal species to examine the adverse effects of human disturbance. Due to the paucity of multi-species study, little is yet known about the relative role interspecific interactions play within communities of carnivores in human-altered systems. In an effort to address this knowledge gap, I examined occurrence patterns of one species known to be sensitive to human disturbance – the wolverine – and compared occurrence patterns among multiple carnivores across a gradient of increasing human land use within a rugged and heterogeneous landscape in the Canadian Rocky Mountains of Alberta. I surveyed carnivore occurrence by combining remote camera trapping and non-invasive genetic tagging. Using a systematic grid based design, medium to large sized carnivores were detected over an area approximately 15,000km2. Consistent with the literature, I found wolverines to be less likely to occur outside of protected areas boundaries and with increasing human-caused landscape disturbance. Contrary to recent climate-focused hypotheses, the spatial pattern of wolverine occurrence was best explained by cumulative effects. When modeling multiple carnivore occurrence across this spatial gradient of human land use, no generality in response was observed. However, a consistent and distinct dissimilarity in response to natural and anthropogenic landscape features was found between wolverine and coyote. The patterns of occurrence led me to infer that habitat condition in the more human-altered systems found along eastern slopes of the Canadian Rocky Mountains is less suitable for some more sensitive species and benefits more human-adapted species. I further hypothesized that an indirect and additive effect of human disturbance is increased interspecific competition between co-occurring carnivores that differentially respond to changes in habitat condition. My results emphasize that by broadening our scope to investigate both single and multiple species, ecologists and managers may better understand the full suite of factors influencing current and future distribution patterns. / Graduate / heimnikki@gmail.com

Agent-based simulation of smart environment finds its application in studying people’s movement to help the design of a variety of applications such as energy utilization, HAVC control and egress strategy in emergency situation. Traditionally, agent-based simulation is not dynamic data driven, they run offline and do not assimilate real sensor data about the environment. As more and more buildings are equipped with various sensors, it is possible to utilize real time sensor data to inform the simulation. To incorporate the real sensor data into the simulation, we introduce the method of data assimilation. The goal of data assimilation is to provide inference about system state based on the incomplete, ambiguous and uncertain sensor data using a computer model. A typical data assimilation framework consists of a computer model, a series of sensors and a melding scheme. The purpose of this dissertation is to develop a data assimilation framework for agent-based simulation of smart environment. With the developed data assimilation framework, we demonstrate an application of building occupancy estimation which focuses on position estimation using the framework. We build an agent based model to simulate the occupants’ movement s in the building and use this model in the data assimilation framework. The melding scheme we use to incorporate sensor data into the built model is particle filter algorithm. It is a set of statistical method aiming at compute the posterior distribution of the underlying system using a set of samples. It has the benefit that it does not have any assumption about the target distribution and does not require the target system to be written in analytic form .To overcome the high dimensional state space problem as the number of agents increases, we develop a new resampling method named as the component set resampling and evaluate its effectiveness in data assimilation. We also developed a graph-based model for simulating building occupancy. The developed model will be used for carrying out building occupancy estimation with extremely large number of agents in the future.

Receptor occupancy assessed by Positron Emission Tomography (PET) can provide important translational information to help bridge information from one drug to another or from animal to man. The aim of this thesis was to develop nonlinear mixed effects methods for estimation of the relationship between drug exposure and receptor occupancy for the two mGluR5 antagonists AZD9272 and AZD2066 and for the 5HT1B receptor antagonist AZD3783. Also the optimal design for improved estimation of the relationship between drug exposure and receptor occupancy as well as for improved dose finding in neuropathic pain treatment, was investigated. Different modeling approaches were applied. For AZD9272, the radioligand kinetics and receptor occupancy was simultaneously estimated using arterial concentrations as input function and including two brain regions of interest. For AZD2066, a model was developed where brain/plasma partition coefficients from ten different brain regions were included simultaneously as observations. For AZD3783, the simplified reference tissue model was extended to allow different non-specific binding in the reference region and brain regions of interest and the possibility of using white matter as reference was also evaluated. The optimal dose-selection for improved precision of receptor occupancy as well as for improved precision of the minimum effective dose of a neuropathic pain treatment was assessed, using the D-optimal as well as the Ds-optimal criteria. Simultaneous modelling of radioligand and occupancy provided a means to avoid simplifications or approximations and provided the possibility to tests or to relax assumptions. Inclusion of several brain regions of different receptor density simultaneously in the analysis, markedly improved the precision of the affinity parameter. Higher precision was achieved in relevant parameters with designs based on the Ds compared to the D-optimal criterion. The optimal design for improved precision of the relationship between dose and receptor occupancy depended on the number of brain regions and the receptor density of these regions. In conclusion, this thesis presents novel non-linear mixed effects models estimating the relationship between drug exposure and receptor occupancy, providing useful translational information, allowing for a better informed drug-development.