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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.
301

Tillämpning av maskininlärning för att införa automatisk adaptiv uppvärmning genom en studie på KTH Live-In Labs lägenheter / Using machine learning to implement adaptive heating; A study on KTH Live-In Labs apartments

Åsenius, Ingrid January 2020 (has links)
The purpose of this study is to investigate if it is possible to decrease Sweden's energy consumption through adaptive heating that uses climate data to detect occupancy in apartments using machine learning. The application of the study has been made using environmental data from one of KTH Live-In Labs apartments. The data was first used to investigate the possibility to detect occupancy through machine learning and was then used as input in an adaptive heating model to investigate potential benefits on the energy consumption and costs of heating. The result of the study show that occupancy can be detected using environmental data but not with 100% accuracy. It also shows that the features that have greatest impact in detecting occupancy is light and carbon dioxide and that the best performing machine learning algorithm, for the used dataset, is the Decision Tree algorithm. The potential energy savings through adaptive heating was estimated to be up to 10,1%. In the final part of the paper, it is discussed how a value creating service can be created around adaptive heating and its possibility to reach the market. / Syftet med den här rapporten är att undersöka om det är möjligt att sänka Sveriges energikonsumtion genom att i lägenheter införa adaptiv uppvärmning som baserar sig på närvaroklassificering av klimatdata. Klimatdatan som använts i studien är tagen från en av KTH Live-In Labs lägenheter. Datan användes först för att undersöka om det var möjligt att detektera närvaro  genom maskininlärning och sedan som input i en modell för adaptiv uppvärmning. I modellen för adaptiv uppvärmning undersöktes de potentiella besparingarna i energibehov och uppvärmningskostnader. Resultaten visar att de bästa featuresen för att klassificera närvaro är ljus och koldioxid. Den maskininlärningsalgoritm som presterade bäst på datasetet var Decision Tree algoritmen. Den potentiella energibesparingen genom införandet av adaptiv uppvärmning uppskattas vara upp till 10,1%. I rapportens sista del diskuteras det hur en värdeskapande tjänst kan skapas kring adaptiv uppvärmning samt dess potential att nå marknaden.
302

Phantom Ocean, Real Impact: Natural Surf Sound Experiments Alter Foraging Activity and Habitat Use Across Taxa

Wardle, Ryan N 01 December 2020 (has links) (PDF)
A growing body of research focuses on how background sounds shape and alter critical elements of animals’ lives, such as foraging behavior, habitat use, and ecological interactions (Bradbury & Vehrencamp, 2011; Barber et al., 2010; Kight & Swaddle, 2011; Shannon et al., 2016). Much of this research has centered on the effects of anthropogenic noise (Dominoni et al., 2020; Francis & Barber, 2013; Ortega, 2012; Swaddle et al., 2015), but recent studies have also revealed that natural sound sources can influence animal behavior (Davidson et al., 2017; Le et al., 2019). Natural sounds, such as crashing surf, can create conditions where signaling and listening are difficult, but how this influences different species’ ecological interactions are unknown. To study the effects of crashing surf sound we experimentally introduced landscape-level acoustic playbacks where surf sound was not naturally present to create a “phantom ocean”. Phantom ocean treatment sites were employed alongside higher frequency “shifted” treatment sites to test for frequency-dependent effects, “real ocean” sites where surf sound was endemic, and ambient control sites. The phantom and shifted treatments were played continuously during the spring and summer of 2017-2019. Within this acoustic experimental landscape we conducted multiple studies to test the effects of crashing surf sound on animal behavior, habitat use, and ecological interactions. Through an artificial caterpillar predation experiment modeled after Roslin et al. (2017), we found that when exposed to natural sound treatments the foraging activity of rodents and arthropods increased, while that of birds declined. A potential explanation for this pattern includes taxon-specific responses reflecting different perceived risk-reward trade-offs in natural sound conditions. To follow this up we performed occupancy modeling on data collected by camera traps set within our system. We observed different responses among groups of species with different functional roles in the community for both detection (p) and occupancy (Ψ) probabilities. Our combined results indicate different species and functional groups have unique foraging behavior and patch use responses to natural sounds, likely based on their ecological interactions. Specifically, Cricetid rodents are likely more active in areas exposed to natural sounds, possibly due to lower perceived predation risk because mesocarnivores are less active. Insectivorous birds are also likely less active under natural sounds conditions, although the frequency of the sound, and the body size and diet of the bird appear influential. Together these findings suggest that natural sounds shape not only individual behavioral adjustments, but also multi-trophic, community level interactions. Our results show that natural sounds are an important driver of ecological interactions, but much remains to be uncovered. The mechanisms by which natural sounds influence individuals, populations, and many other aspects of ecology remain unexplored and provide fertile ground for future inquiry.
303

Hydrogen Absorption in Metal Hydrides : Transmission of light in relation to hydrogen concentration and site occupancy of ultrathin vanadium films

Sörme, David January 2022 (has links)
In this study the effect of hydrogenation on the optical properties in the wavelength range 400-1023 nm of an ultrathin iron-vanadium superlattice is investigated. Specifically, mea- surements of transmission are performed under different states of hydrogenation, along with measurements of absolute hydrogen concentration and hydrogen site occupancy. The trans- mission measurements are used to construct pressure-concentration isotherms. Isotherms and transmission data are in turn correlated to concentration and hydrogen occupancy.  The results show a wavelength dependent decrease in transmission with hydrogenation. The decrease is greatest around 550 nm, and the wavelength of maximum decrease shifts to higher wavelengths with increasing hydrogen pressure. The non-uniform decrease will make the use of transmission as a measurement of hydrogen concentration dependent on the wavelength of the probing light.  15N resonant NRA is used to perform direct, real-space measurement of absolute hydro- gen concentration. The achieved concentrations are 0.092, 0.38 0.40 H/V. Comparing the concentrations and corresponding transmissions to the location of the plateau region in the transmission based isotherms, it appears that the system is in a single phase at 0.38 and 0.40 H/V, and in a mixed phase at 0.092 H/V. Using a combination of resonant NRA and RBS, while exploiting crystal lattice ion channeling, indirect measurements of hydrogen site occupancy are performed. At all investigated concentrations the system does not display tetrahedral site occupancy, but it remains uncertain whether the occupancy is octahedral or some dislocated octahedral-tetrahedral intermediate.  The relation of hydrogen concentration and optical transmission is investigated via a linear regression analysis. The data points generally deviate by more than one standard deviation from the fitted lines, and lie outside of the error estimation. These deviations might indicate that a linear model is inappropriate, where one possible explanation could be that the mapping from transmission to concentration is dependent on the phase of the system. / Den här studien undersöker upptag av väte i en supertunn kristallstruktur bestående av omväxlande lager av vanadin och järn, samt vätets inverkan på de optiska egenskaperna i våglängdsområdet 400-1023 nm. Specifikt genomförs mätningar av genomsläpp av ljus, under olika nivåer av väteupptag. I samband med dessa mätningar genomförs också mätningar av absolut vätekoncentration och av väteatomernas position i kristallstrukturen. Mätningarna av ljusgenomsläpp används för att skapa isotermkuror över tryck och koncentration. Isotermkurvorna och genomsläppligheten av ljus korreleras till vätekoncentration och väteatomernas position i kristallstrukturen.  Resultaten visar en våglängdsberoende minskning av ljusgenomsläppligheten med en ökande mängd väte i kristallstrukturen. Minskningen är som störst omkring 550 nm, samtidigt som våglängden för störst minskning flyttas mot högre våglängder med högre koncentration av väte. Att minskningen i genomsläpplighet är beroende av våglängd innebär att ljusgenomsläpp som metod för att mäta vätekoncentration är beroende av den ljusvåglängd som används. Metoden 15N resonant NRA används för att genomföra direkta mätningar av absolut vätekoncentration. De uppmätta koncentrationerna är 0.092, 0.38 och 0.40 H/V. När dessa koncentrationsmätningar jämförs med genomsläpplighet och tillhörande isotermkurvor, så verkar det som att systemet befinner sig i en enskild fas vid koncentrationerna 0.38 och 0.40 H/V, och i en blandad fas vid koncentrationen 0.092 H/V. Indirekta mätningar av vätets position i kristallstrukturen genomförs baserat på en kombination av resonant 15N NRA och RBS, där det utnyttjas att projektiljonerna under vissa förutsättningar kan komma att styras in i kristallstrukturen (på engelska crystal lattice ion channeling). Vid de tre uppmätta koncentrationerna så visar systemet inga tecken på att väteatomerna finns på tetrahedrala positioner. Det är inte helt uppenbart om väteatomerna istället finns på oktahedrala positioner, eller om det handlar om förskjutna positioner som är mellanliggande till oktahedrala och tetrahedrala. Relationen mellan vätekoncentration och optisk genomsläpplighet analyseras med linjär regression. Datapunkterna avviker generellt med mer än en standardavvikelse från de anpassade linjerna, och ligger utanför feluppskattningen. De här avvikelserna kan indikera att en linjär modell inte är lämplig, och en möjlig förklaring kan vara att ljusgenomsläppligheten beror av den fas i vilken systemet befinner sig.
304

Resource Selection, Home Range and Habitat Associations of the Southern Fox Squirrel (<i>Sciurus niger niger</i>) in the Piedmont and Coastal Plain of Virginia

Guill, Marissa Hahn 01 September 2023 (has links)
The southern fox squirrel (Sciurus niger niger) has the northernmost part of its range in Virginia. For the past 100 years, southern fox squirrels have been declining due to habitat fragmentation, cover type conversion, and fire suppression. Decrease in growing season burns, hardwood encroachment and forest mesophication have transformed pine hardwood woodlands and pine (Pinus spp.) savanna habitats that southern fox squirrels prefer to hardwood dominant habitats that eastern gray squirrels (Sciurus carolinenisis) prefer. These habitat changes have the potential to increase competition among the two species. The main objectives of my study were to investigate the general resource needs, occupancy, and home range of southern fox squirrels as well as the impact of resource partitioning and possible competition with eastern gray squirrels in the Piedmont and Coastal Plain of Virginia. I captured, radio collared and tracked four individuals at Big Woods Wildlife Management area and Piney Grove Complex using 95% and 50% kernel density estimate. I found an average male home range 173.49 ha (SE = 25.73, N = 2) and 40.62 ha (SE = 5.87, N = 2) and an average female home range of 28.51 ha (SE = 0.49, N = 2) and 4.71 ha (SE = 0.34, N = 2). I then identified the second and third order habitat selection in which my top models identified selection for pine savanna cover types (β = 2.095, SE = 0.158), increasing number of burns since 2019 (β =1.24, SE = 0.098), and decreased time between burns (β = -0.233, SE = 0.097). I used two-species occupancy modeling which reflected that gray squirrel occupancy increased with increasing time since last prescribed burn. However, southern fox squirrel occupancy, in the absence of gray squirrels, decreased with increasing time since last burn. My informed single-season occupancy model confirmed that southern fox squirrel occupancy decreased with time since the last burn. Presence in the absence of gray squirrels suggests that southern fox squirrels are selecting habitats on BWPGC with respect to both resource needs and competition with gray squirrel. Additionally, my level-of-effort (LOE) analysis indicated that 7 consecutive days of camera trapping without a southern fox squirrel detection would provide 90% confidence of the species' absence in areas burned 2 or more years prior to sampling in southeastern Virginia. Further management for southern fox squirrels in the future should focus on high rotational (short fire return interval) burns in areas of savanna as well as pine-hardwood mixed areas and hardwood-pine savanna ecotones. / Master of Science / The southern fox squirrel (Sciurus niger niger) is a subspecies of fox squirrel that ranges from southeastern Virginia down to northern Florida. All throughout its range in the Southeast, southern fox squirrel habitat has been fragmented from natural mixed pine-hardwood woodland forests to agriculture and high rotation pine plantations. Additionally, habitat has been further transformed by the lack of prescribed fire as a management tool on the landscape. This has in turn created sparse and fragmented local populations of southern fox squirrels as well as possible competition with gray squirrels. Further, the southern fox squirrel has not been studied in Virginia in over 20 years and management recommendations are lacking. I studied the resource needs, occupancy, home range and competition of southern fox squirrels in two physiographic regions of Virginia: the Coastal Plain and Piedmont regions. The Coastal Plain field site was Big Woods Wildlife Management Area and The Nature Conservancy's Piney Grove- both adjacent to each other. The Piedmont field site was Military Training Center Fort Barfoot. Here I utilized camera trapping, nest box monitoring, live trapping, and radio tracking to assess the resources they are utilizing in each area through home range analyses. I found that southern fox squirrels are selecting areas that have low fire return intervals and are located in pine savanna habitats. Therefore, fire should be prioritized as a management tool for southern fox squirrel habitat in pine savanna areas. I also used camera trapping data to identify the possible competition among gray and fox squirrels and fox squirrel detection through occupancy modeling. My findings reflected that there is apparent competition between southern fox squirrels and eastern gray squirrels and that southern fox squirrels are selecting heavily burned areas not only for their resource needs, but also because gray squirrels are absent. I concluded through my studies that the southern fox squirrel currently occupies southeastern Virginia, particularly in the Coastal Plain, however at low numbers. This could be due to suitable habitat on Big Woods/Piney Grove, but the surrounding habitat is of marginal quality. Further, in documenting southern fox squirrels, multi day camera surveys in mixed pine-hardwood woodland and pine savannas should be prioritized. Also, in aims to increase the presence of southern fox squirrels on the landscape, short rotation prescribed burning should be prioritized as well as additionally considering meditation among gray squirrel and fox squirrel competition.
305

EVALUATION OF SURVEY METHODS USED TO DETERMINE SEMI-AQUATIC MAMMAL OCCUPANCY IN NORTHEASTERN INDIANA

Eleanor L Di Girolamo (13169508) 29 July 2022 (has links)
<p>  </p> <p>Semi-aquatic mammals, such as American beavers (<em>Castor canadensis</em>), muskrats (<em>Ondatra zibethicus</em>), North American river otters (<em>Lontra canadensis</em>), and American mink (<em>Neogale</em> <em>vison</em>), often play important roles in their ecosystem. Beavers and muskrats can manipulate plant community structure through the use of woody debris and forbs. As mesocarnivores, North American river otters and American mink can also drive community structure through the predation. Traditionally, these species are monitored using sign surveys (i.e., walking transects and visually identifying scat, tracks, and latrines). Camera trapping has also been used to survey semi-aquatic species occupancy to a lesser extent. However, due to their almost exclusive use of edge habitat, they may be ideal species to camera trap. Another more recently employed survey method is environmental DNA (eDNA), which involves the extraction of DNA from environmental samples (such as soil, water, air, and snow) to determine species occupancy. In this study, I evaluate environmental DNA and camera trapping as survey methods for detecting semi-aquatic mammals around northeastern Indiana. In the first chapter, I used eDNA sampling and camera trapping to monitor seven sites for three weeks during March – May 2021 in order to determine the presence of American mink. I found that the naïve occupancy for each site was 0.86. Although the detection probability of eDNA was lower than that of camera trapping (0.25 and 0.36, respectively), the occupancy models created suggest that there was no difference in detection probability between the two methods. I also compared the cost and time spent per sample and found that both were 20% lower for eDNA than camera trapping. The results of my study suggest eDNA may be a cost- and time-effective method for surveying for American mink occupancy. The objective of my second chapter was to determine the number of camera traps required to obtain reliable data for detecting semi-aquatic mammals. A minimum requirement for number of camera traps would be useful knowledge for wildlife managers in terms of budgeting and resource management and could also help to refine current camera trapping methodologies. I camera trapped four ponds for four weeks during June – July 2021, varying the number of camera traps (1 – 5) used at each pond each week. I collected a total of 66,543 photos and detected one semi-aquatic mammal throughout the study period (<em>Neogale vison</em>). Due to the lack of semi-aquatic mammals detected, I could not perform any analyses.</p>
306

BLANDING’S TURTLE OCCUPANCY AND ABUNDANCE IN SOUTHERN MICHIGAN AND OHIO

Daniel James Earl (13943547) 13 October 2022 (has links)
<p>  </p> <p>Blanding’s Turtle populations face direct threats to their survival. To help protect populations, habitats that can best support Blanding’s Turtle populations need to be identified across their range. Blanding’s Turtles have been a difficult to detect species and may be present at a site even if not detected during targeted surveys. Additionally, Blanding’s Turtles may be present at a site but may have little to no recruitment so additional measures of site suitability beyond species presence are needed to determine more suitable or higher quality habitats. In my research, I attempt to determine suitability of sites for Blanding’s Turtles across Michigan and Ohio using data collected from rapid assessment protocols fit into single season occupancy models with wetland and upland landcover types as co-variates of occupancy. To further determine the suitability of sites based on these data, I created single season occupancy models for juvenile Blanding’s Turtles and used N-mixture abundance modelling to determine relative abundance of Blanding’s Turtles at a site using the same landcovers as covariates of occupancy and abundance. Both modelling frameworks also allowed me to include detection covariates that could increase Blanding’s Turtle detection in future surveys. </p> <p>Detection was largely influenced by Julian date with the highest probability of detection occurring from mid-May through late June. Length of trapping surveys was also found to influence Blanding’s Turtle detection with a substantial decrease in daily trap capture rates by the fourth trap night of a survey. Michigan occupancy and abundance models found that the most suitable sites in Michigan would have high percentages of high-quality upland forest and woody wetland landcovers, with the percentage of open water supporting the occupancy of turtles but having no discernable effect on abundance. Total upland forest also significantly increased the probability of juvenile occupancy in Michigan. In Michigan, I also observed that survey method can greatly influence the estimates of occupancy and abundance, and I determined that visual surveys cannot accurately determine these estimates. The heavily disturbed nature of Ohio’s landscape took away from the predictive power of landcovers used in my research for Blanding’s Turtle occupancy and abundance. The vast difference between occupied habitats in Michigan and Ohio also takes away from the predictive power of the regional level model and relative abundance of Blanding’s Turtle populations cannot be accurately determined at this scale using the spatial covariates I included. However, total undisturbed forest and total wetland proved to be positive covariates of Blanding’s Turtle abundance and occupancy for adult and juvenile turtles across both states, but the habitats used in each state vary greatly so future conservation decisions should be made on the state level as largest spatial scale. Using my models for Michigan suitable sites can be determined within the state and compare relative abundance between sites to determine healthier populations. For future analysis in Ohio, different, smaller scales spatial covariates should be used to explain differences in occupancy and abundance between sites.</p>
307

Tillämpning av maskininlärning för att införa automatisk adaptiv uppvärmning genom en studie på KTH Live-In Labs lägenheter

Vik, Emil, Åsenius, Ingrid January 2020 (has links)
The purpose of this study is to investigate if it is possible to decrease Sweden's energy consumption through adaptive heating that uses climate data to detect occupancy in apartments using machine learning. The application of the study has been made using environmental data from one of KTH Live-In Labs apartments. The data was first used to investigate the possibility to detect occupancy through machine learning and was then used as input in an adaptive heating model to investigate potential benefits on the energy consumption and costs of heating. The result of the study show that occupancy can be detected using environmental data but not with 100% accuracy. It also shows that the features that have greatest impact in detecting occupancy is light and carbon dioxide and that the best performing machine learning algorithm, for the used dataset, is the Decision Tree algorithm. The potential energy savings through adaptive heating was estimated to be up to 10,1%. In the final part of the paper, it is discussed how a value creating service can be created around adaptive heating and its possibility to reach the market.
308

Ecology of Two Rare Amphibians of the Gulf Coastal Plain

Gorman, Thomas Andrew 30 April 2009 (has links)
Globally, amphibian species have been in decline and a wide range of factors have been purported to be driving the decline. The Gulf Coastal Plain of Florida has a high degree of endemism and rarity and the biodiversity in the region includes a diverse suite of amphibian species. Degradation of habitat has been considered by many to be a major part of amphibian declines, however amphibian declines are complex and in many cases multiple factors are occurring in concert. My dissertation research examined aspects of habitat ecology and occupancy for two rare amphibians, Florida Bog Frog (Rana okaloosae) (Chapter 1, 2, and 3) and Reticulated Flatwoods Salamander (Ambystoma bishopi) (Chapter 5), that are both restricted to the Northern Gulf Coastal Plain. Further, for R. okaloosae I examined the influence of a sympatric congener, Bronze Frog (R. clamitans clamitans), on microhabitat selection (Chapter 1) and growth of tadpoles (Chapter 4). My overall goal was to be able to elucidate factors that limit the geographic range of R. okaloosae and A. bishopi and to identify habitat characteristics that managers could maintain or create to conserve or increase populations of these species. My first chapter examined the microhabitat relationships between R. okaloosae and R. c. clamitans. Rana okaloosae is endemic to northwestern Florida and is sympatric with R. c. clamitans, a more common and widely distributed congener. Further, the two species appeared to be syntopic, have overlapping breeding seasons, and are known to hybridize. The objectives of this chapter were to assess the microhabitat selection of both species and to assess differences in microhabitat use of males of both species during the breeding season. My modeling of habitat selection and comparison of variables used by each species suggests that males of these species select different resources when calling. Therefore, these sympatric ranids select for different resources at a fine scale, however there does appear to be some overlap among some selected habitat characteristics. In Chapter 2, I assessed the habitat use of R. okaloosae at multiple spatial scales. I surveyed for R. okaloosae and evaluated habitat characteristics at used sites and sites where I had no detections to develop among- and within-stream habitat models for R. okaloosae. Rana okaloosae used habitats with high amounts of emergent vegetation at both the among-stream scale and the within-stream scale. Emergent vegetation appears frequently in models of anuran habitat selection, particularly those that occur in fire-dominated landscapes. Further understanding the habitat requirements of R. okaloosae will allow land managers to use appropriate management activities (e.g., prescribed fire) that will increase emergent vegetation and potentially restore habitat that may help increase populations of R. okaloosae. In Chapter 3, I conducted aural surveys for R. okaloosae at two different spatial scales: range-wide and stream-level scales to understand how occupancy and colonization of R. okaloosae may be influenced by scale. My results suggest that at both spatial scales occupancy of R. okaloosae was best described by the presence of mixed forest wetlands at survey sites. At the range-wide scale, colonization and detection were constant across years, however, at the stream-level scale, colonization was predicted by the number of years since last fire and detection was best predicted by the additive combination of relative humidity and temperature. Occupancy of R. okaloosae was patchy at the range-wide and at the stream-level scales and colonization was low at both scales, while derived estimates of local extinction were moderately high. While R. okaloosae still occur in 3 watersheds where they were initially observed in the 1980's, one of the three watersheds appears to be very isolated and detections there are becoming very infrequent. In Chapter 4, I experimentally evaluated the effects of R. c. clamitans tadpoles on R. okaloosae tadpoles. My results suggest that there was limited influence of R. c. clamitans on R. okaloosae. Conversely, it appeared that Rana c. clamitans was more susceptible to intraspecific competition than interspecific competition. The lack of a strong competitive effect of Rana c. clamitans on Rana okaloosae suggests that competitive interactions among tadpoles may have a limited effect at the densities I examined. In Chapter 5, our objectives were to evaluate a suite of within-pool factors (i.e., vegetation structure, water level, and an index to presence of fish) that could influence occupancy of breeding wetlands by larval flatwoods salamanders on Eglin Air Force Base in Florida, USA. Site occupancy over a 4 year period was best described by a model that incorporated high herbaceous vegetation cover and open canopy cover. Detection probability was assessed, but it varied among years and was not included in the model. Our study suggests that managing the breeding habitat of flatwoods salamander for open canopies and dense herbaceous vegetation may contribute to this species' recovery. In conclusion, Chapters 1-3 of my dissertation contribute to a growing understanding about the habitat ecology of R. okaloosae. I have evaluated habitat use of R. okaloosae at multiple spatial scales. At the finest spatial scale R. okaloosae selected for sites that had an abundance of cover probably decreasing their risk of predation (Chapter 1). Similarly, in Chapter 2 at two spatial scales, among and within-streams, R. okaloosae selected for emergent vegetation. Finally, at the broadest spatial scale, range-wide, R. okaloosae were found to be associated with mixed forest wetlands (Chapter 3). I did not find strong support for competition between R. okaloosae and R. c. clamitans tadpoles, although there was some evidence of asymmetric competition (Chapter 4). Further, adult males of each species did not select the same habitat characteristics for calling sites, so there appeared to be some resource partitioning (Chapter 1). Finally, the presence of A. bishopi larvae was found to be associated with herbaceous vegetation and moderate amounts of canopy cover (Chapter 5). Results from Chapter 2 and 5 suggest that both R. okaloosae and A. bishopi are associated with habitat conditions that are likely a result of fire penetrating wetland areas. / Ph. D.
309

Estimation of Runway Throughput with Reduced Wake Separation, Runway Optimization, and Runway Occupancy Time Consideration

Li, Beichen 22 September 2022 (has links)
This thesis estimates potential runway throughput gains using a reduced wake separation based on the 123 most prevalent aircraft in the United States fleet. The analysis considers Runway Occupancy Time (ROT) constraint factors and existing geometric design factors. This research extracts the historic data from Airport Surface Detection Equipment Model X (ASDE-X) for analysis. The Runway Exit Design Interactive Model (REDIM) is used to optimize the runway exit locations and reduce ROT. The runway throughput and safety factors are generated from a Monte Carlo runway simulator. This thesis focuses on selected US airport runways that could benefit from geometric optimization. The study aims to estimate ROT improvements through improved runway exit locations and the changes in runway throughput considering ROT constraint factors. The results of the thesis show that Dallas Fort Worth International Airport (DFW) runway 35C and Denver International Airport (DEN) runway 16R have the potential to improve the ROT. After the optimization to locate runway exits, the ROT time of the RECAT group F and G aircraft (greater than 90% of the arrivals) was reduced by three to five seconds (a very significant effect). After the ROT reductions and with the application of reduced wake separation criteria with the ROT constraint factor applied, the arrival-only capacity of DFW runway 35C improved by 3.5 arrivals per hour. The arrival-only capacity on DEN runway 16R improved by 2.14 arrivals per hour. Both runways maintained a probability of violation between time-based separation and ROT time at around 1.5%. The study concludes that the application of reduced wake separation criteria alone is a necessary but insufficient condition to improve the efficiency of arrival runways. Through careful improvements of runway exit locations, reductions in ROT provide reliability and efficiency to the operation of runways. / Master of Science / This thesis estimates potential runway throughput gains using a reduced wake separation based on the 123 most prevalent aircraft in the United States fleet. The analysis considers Runway Occupancy Time (ROT) constraint factors and existing geometric design factors. This research extracts the historic data from Airport Surface Detection Equipment Model X (ASDE-X) for analysis. The Runway Exit Design Interactive Model (REDIM) is used to optimize the runway exit locations and reduce ROT. The runway throughput and safety factors are generated from a Monte Carlo runway simulator. This thesis focuses on selected US airport runways that could benefit from geometric optimization. The study aims to estimate ROT improvements through improved runway exit locations and the changes in runway throughput considering ROT constraint factors. The results of the thesis show that Dallas Fort Worth International Airport (DFW) runway 35C and Denver International Airport (DEN) runway 16R have the potential to improve the ROT. After the optimization to locate runway exits, the ROT time of the RECAT group F and G aircraft (greater than 90% of the arrivals) was reduced by three to five seconds (a very significant effect). After the ROT reductions and with the application of reduced wake separation criteria with the ROT constraint factor applied, the arrival-only capacity of DFW runway 35C improved by 3.5 arrivals per hour. The arrival-only capacity on DEN runway 16R improved by 2.14 arrivals per hour. Both runways maintained a probability of violation between time-based separation and ROT time at around 1.5%. The study concludes that the application of reduced wake separation criteria alone is a necessary but insufficient condition to improve the efficiency of arrival runways. Through careful improvements of runway exit locations, reductions in ROT provide reliability and efficiency to the operation of runways.
310

Ecology, Habitat Use, and Conservation of Asiatic Black Bears in the Min Mountains of Sichuan Province, China

Trent, Jewel Andrew 13 July 2010 (has links)
This project was initiated in an attempt to address the paucity of data on Asiatic black bears (Ursus thibetanus) in Mainland China. Field work was carried out from May 2004 – August 2006 within the Tangjiahe National Nature Reserve in northwestern Sichuan Province, China. Initial methodology relied on trapping and GPS radio-collaring bears, but due to extreme difficulty with capturing a sufficient sample size, I expanded the study to include reproduction, feeding analysis from scats and sign, and occupancy modeling from sign surveys. I documented the home ranges of an adult female (100% MCP = 107.5km2, n=470 locations) and a sub-adult female (100%MCP = 5.9km2, n=36 locations) Asiatic black bear. I also documented two birthing occasions with a total of four male cubs produced and eight bear den sites. I collected feeding data from 131 scat samples and 200 bear sign transects resulting in 50 identified food items consumed by Asiatic black bears. I also employed the program PRESENCE to analyze occupancy data using both a standard grid repeated sampling technique and an innovative technique of aging bear sign along strip transect surveys to represent repeated bear occupancy over time. Conservation protection patrolling and soft mast were shown to be the most important factors determining the occupancy of an area by Asiatic black bears in Tangjiahe Nature Reserve, Sichuan Province, China. / Master of Science

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