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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.
191

Monitoring biological heterogeneity in a northern mixed prairie using hierarchical remote sensing methods

Zhang, Chunhua 18 December 2006
Heterogeneity, the degree of dissimilarity, is one of the most important and widely applicable concepts in ecology. It is highly related to ecosystem conditions and features wildlife habitat. Grasslands have been described as inherently heterogeneous because their composition and productivity are highly variable across multiple scales. Therefore, biological heterogeneity can be an indicator of ecosystem health. The mixed prairie in Canada, characterized by its semiarid environment, sparse canopy, and plant litter, offers a challenging region for environmental research using remote sensing techniques. This thesis dwells with the plant canopy heterogeneity of the mixed prairie ecosystem in the Grasslands National Park (GNP) and surrounding pastures by combining field biological parameters (e.g., grass cover, leaf area index, and biomass), field collected hyperspectral data, and hierarchical resolution satellite imagery. The thesis scrutinized four aspects of heterogeneity study: the importance of scale in grassland research, relationships between biological parameters and remotely collected data, methodology of measuring biological heterogeneity, and the influence of climatic variation on grasslands biological heterogeneity. First, the importance of scale is examined by applying the semivariogram analysis on field collected hyperspectral and biophysical data. Results indicate that 15 - 20 m should be the appropriate resolution when variations of biological parameters and canopy reflectance are sampled. Therefore, it is reasonable to use RADARSAT-1, Landsat TM, and SPOT images, whose resolutions are around 20 m, to assess the variation of biological heterogeneity. Second, the efficiency of vegetation indices derived from SPOT 4 and Landsat 5 TM images in monitoring the northern mixed prairie health was examined using Pearsons correlation and stepwise regression analyses. Results show that the spectral curve of the grass canopy is similar to that of the bare soil with lower reflectance at each band. Therefore, vegetation indices are not necessarily better than reflectance at green and red wavelength regions in extracting biological information. Two new indices, combining reflectance from red and mid infrared wavelength regions, are proposed to measure biological parameters in the northern mixed prairie. Third, texture analysis was applied to quantify the biological variation in the grasslands. The textural parameters of RADARSAT imagery correlated highly with standard deviation of the field collected canopy parameters. Therefore, textural parameters can be applied to study the variations within the mixed prairie. Finally, the impacts of climatic variation on grassland heterogeneity at a long time scale were evaluated using Advanced Very High Resolution Radiometer (AVHRR) , Normalized Difference Vegetation Index (NDVI), Maximum Value Composite (MVC), and SPOT Vegetation NDVI MVC imagery from 1993 to 2004. A drought index based on precipitation data was used to represent soil moisture for the study area. It was found that changes of temperature and precipitation explain about 50% of the variation in AVHRR NDVI (i.e., temporal heterogeneity) of the northern mixed prairie. Trend line analysis indicates that the removal of grazing cattle carry multiple influences such as decreasing NDVI in some parts of the upland and valley grassland and increasing NDVI in the valley grassland. Results from this thesis are relevant for park management by adjusting grassland management strategies and monitoring the changes in community sizes. The other output of the thesis is furthering the remote sensing investigation of the mixed prairie based on information of the most appropriate resolution imagery.
192

Rescheduling blocked Vehicles at Daimler AG

Caap Hällgren, Eric January 2012 (has links)
The purpose of this thesis is to develop a heuristic solution for the static problem of resequencing unblocked vehicles as a part of an ongoing research project at Daimler AG. The target client of this project is Mercedes-Benz Cars. An unblocked vehicle is defined as a vehicle that for some reason could not be processed in its given time slot but at a later point in time needs to be inserted into the production sequence. Work overload is defined as work that the worker is unable to finish prior to reaching the station border. The resequencing problem can be described as finding new positions for a set of unblocked vehicles in a sequence of previously not blocked vehicles, such that the new sequence containing the previously not blocked vehicles and the additional unblocked vehicles causes as little work overload as possible. A decision has to be made in real-time, forcing the solution method to return a solution within a cycle time. Today, Mercedes-Benz Cars uses the sequencing approach “car sequencing”. This approach relies on so called spacing constraints, which basically means, trying to distribute work intensive vehicles as evenly as possible over the planning horizon and thereby enabling a hopefully smooth production. The car sequencing approach needs limited information. The difficulty is to find spacing constraints that fits the high level of product customization characterizing a modern car manufacturer. To overcome these difficulties, a new approach is being considered, namely the mixed-model sequencing, which takes more detailed data into account than the car sequencing approach but on the other hand is more costly in terms of computation. To this end, a simple but promising tabu search scheme was developed, that for many instances was able to find the optimal solution in less than 30 seconds of computing time and that also clearly outperformed all benchmark heuristics.
193

From Policy to Practice: Implementation of Georgia's Medicaid Family Planning Waiver Program

Blake, Sarah 10 May 2013 (has links)
From Policy to Practice: Implementation of Georgia’s Medicaid Family Planning Waiver Program Sarah C. Blake, MA 282 pages Directed by Dr. John Thomas The purpose of this research was to examine the implementation of Georgia’s Medicaid family planning program, known as Planning for Healthy Babies® or P4HB®. This program is the first such program to provide both family planning services and inter-pregnancy care services through a Medicaid expansion to low-income, uninsured women. An evaluative case study design was employed using mixed methods. These methods incorporated process measures to study the implementation of P4HB® and to assess whether P4HB® was implemented as planned We incorporated theory from the policy implementation and health care access literatures to understand what served as facilitators or barriers to successful implementation. Findings suggest that despite precise goals and objectives, formal guidance about the program did not incorporate clear implementation planning. Many stakeholders, including advocates, providers, and representatives from implementing agencies felt left out of the implementation process and did not feel invested in the program. Considerable confusion existed among eligible clients and providers about the nature and scope of the P4HB® program. This lack of awareness and understanding about P4HB® likely contributed to the program’s low enrollment and participation in the first year of its implementation. As many states prepare to expand their Medicaid programs under the Patient Protection and Affordable Care Act (ACA), this study provides important lessons for policy planning and implementation.
194

Monitoring biological heterogeneity in a northern mixed prairie using hierarchical remote sensing methods

Zhang, Chunhua 18 December 2006 (has links)
Heterogeneity, the degree of dissimilarity, is one of the most important and widely applicable concepts in ecology. It is highly related to ecosystem conditions and features wildlife habitat. Grasslands have been described as inherently heterogeneous because their composition and productivity are highly variable across multiple scales. Therefore, biological heterogeneity can be an indicator of ecosystem health. The mixed prairie in Canada, characterized by its semiarid environment, sparse canopy, and plant litter, offers a challenging region for environmental research using remote sensing techniques. This thesis dwells with the plant canopy heterogeneity of the mixed prairie ecosystem in the Grasslands National Park (GNP) and surrounding pastures by combining field biological parameters (e.g., grass cover, leaf area index, and biomass), field collected hyperspectral data, and hierarchical resolution satellite imagery. The thesis scrutinized four aspects of heterogeneity study: the importance of scale in grassland research, relationships between biological parameters and remotely collected data, methodology of measuring biological heterogeneity, and the influence of climatic variation on grasslands biological heterogeneity. First, the importance of scale is examined by applying the semivariogram analysis on field collected hyperspectral and biophysical data. Results indicate that 15 - 20 m should be the appropriate resolution when variations of biological parameters and canopy reflectance are sampled. Therefore, it is reasonable to use RADARSAT-1, Landsat TM, and SPOT images, whose resolutions are around 20 m, to assess the variation of biological heterogeneity. Second, the efficiency of vegetation indices derived from SPOT 4 and Landsat 5 TM images in monitoring the northern mixed prairie health was examined using Pearsons correlation and stepwise regression analyses. Results show that the spectral curve of the grass canopy is similar to that of the bare soil with lower reflectance at each band. Therefore, vegetation indices are not necessarily better than reflectance at green and red wavelength regions in extracting biological information. Two new indices, combining reflectance from red and mid infrared wavelength regions, are proposed to measure biological parameters in the northern mixed prairie. Third, texture analysis was applied to quantify the biological variation in the grasslands. The textural parameters of RADARSAT imagery correlated highly with standard deviation of the field collected canopy parameters. Therefore, textural parameters can be applied to study the variations within the mixed prairie. Finally, the impacts of climatic variation on grassland heterogeneity at a long time scale were evaluated using Advanced Very High Resolution Radiometer (AVHRR) , Normalized Difference Vegetation Index (NDVI), Maximum Value Composite (MVC), and SPOT Vegetation NDVI MVC imagery from 1993 to 2004. A drought index based on precipitation data was used to represent soil moisture for the study area. It was found that changes of temperature and precipitation explain about 50% of the variation in AVHRR NDVI (i.e., temporal heterogeneity) of the northern mixed prairie. Trend line analysis indicates that the removal of grazing cattle carry multiple influences such as decreasing NDVI in some parts of the upland and valley grassland and increasing NDVI in the valley grassland. Results from this thesis are relevant for park management by adjusting grassland management strategies and monitoring the changes in community sizes. The other output of the thesis is furthering the remote sensing investigation of the mixed prairie based on information of the most appropriate resolution imagery.
195

Numerical Model of a Reciprocating Rod Seal, Including Surface Roughness and Mixed Lubrication

Maser, Nicholas Brian 25 August 2006 (has links)
Currently, finite element analysis (FEA) serves as the only analytical tool used in the evaluation of seals. The FEA does not allow the dynamic analysis of the seal, which must be performed experimentally. As a result, the designing of a seal can be a costly and extensive procedure. The aim of this project has been to develop a numerical model and computer program that will have the ability to predict key seal performance characteristics, such as leakage and friction. This numerical model provides a means for evaluating potential seal designs, which can be performed without having to endure the costs of creating and evaluating the performance of the seal. Thus, the numerical model reduces the time and cost involved in evaluating seal designs. The numerical model developed differs from previous models as the effects of mixed lubrication and surface roughness are investigated. This model consists of three coupled analyses of fluid mechanics, deformation, and contact mechanics. After computational procedure has converged coupling the three analyses, auxiliary calculations are performed to obtain the quantities of leakage rate and friction force. These obtained results then allow the evaluation of the seal design, which will lead to better seal designs with lower friction and less (or no) leakage. The results obtained for a typical hydraulic seal show that the leakage characteristics depend strongly on the seal roughness.
196

Effects of Feedstocks and Inoculum Sources on Mixed-Acid and Hydrogen Fermentations

Forrest, Andrea Kelly 2010 December 1900 (has links)
With increasing energy demand, decreasing oil supply, and continuously accumulating waste in landfills, the interest in converting lignocellulosic biomass to liquid fuels has grown. The MixAlco™ process requires no exogenous enzymes, no sterility, can be adapted to any biodegradable feedstock, and converts lignocellulosic biomass into valuable chemicals and transportation fuels. This work focuses on the effects different feedstocks and inocula have on mixed-acid/hydrogen fermentations. When volatile solids (VS) are digested, mixed-acid fermentations produce hydrogen gas as a secondary byproduct. Hydrogen is only produced when there is an excess of NADH within the cell and when the energy selectivity (gamma) of the system has not been met. Continuous fermentations of paper produced 16.7 g carboxylic acid/L and 15.7 mL H2/g VS digested. Continuous fermentations of pretreated bagasse produced 17.1 g carboxylic acid/L and 41.1 mL H2/g VS digested. Both fermentations produced a fraction of the theoretical amount of hydrogen. The paper fermentation had a hydrogen percent yield of 6.9 percent, whereas the bagasse fermentation had a hydrogen percent yield of 22.6 percent. Hydrogen production was capped at this level because gamma had been met for these systems. The Bioscreening Project, a joint project between three departments, sought to improve the MixAlco™ process by finding natural cultures containing high biomass converters and high acid producers. A total of 505 inoculum samples were collected from 19 sites and screened using paper and yeast extract fermentations. The best converters were analyzed with Continuum Particle Distribution Modeling (CPDM). Nine inocula were run in paper and yeast extract countercurrent fermentations in which the overall performance varied less than 13 percent. Comparisons between six countercurrent train cultures showed an average culture similarity of 0.40 (Yue-Clayton similarity). With the dissimilar microbial cultures and the very similar fermentation performance, the performance of the MixAlco™ process depends on fermentation conditions, not on the microorganisms. Batch fermentations of office paper wastes, pineapple residue, Aloe vera rinds, wood molasses, sugar molasses, extracted algae, non-extracted algae, crude glycerol, obtained from the biodiesel process, and pretreated water hyacinths produced sufficient carboxylic acids and had sufficiently high conversions to be viable substrates for the MixAlco™ process.
197

A 10-bit 30-MS/s Pipeline ADC for DVB-H Receiver Systems and Mixed-Voltage Tolerant I/O Cell Design

Chang, Tie-Yan 11 July 2007 (has links)
The first topic of this thesis proposes a 10-bit, 30 Msample/s pipeline analog-to-digital converter (ADC) suitable for digital video broadcasting over handheld (DVB-H) systems. The ADC is based on the 1.5-bit-per-stage pipeline architecture. The proposed design is implement- ed by 0.18 um CMOS technology. The input range is 2 V peak-to-peak differential signals, and the post-layout simulation result shows that the spurious-free dynamic range (SFDR) is 57.85 dBc with a full-scale sinusoidal input at 700 KHz. The maximum power consumption is 37 mW given a 3.3 V power supply. The core area is 0.27 mm2. The second topic is to propose a fully mixed-voltage-tolerant I/O cell implemented using typical CMOS 2P4M 0.35 um process. Unlike traditional mixed-voltage-tolerant I/O cell, the proposed design can transmit and receive the digital signals with voltage levels of 5/3.3/1.8 V. By using stacked PMOS and stacked NMOS at the output stage and a voltage level converter providing appropriate control voltages for the gates of the stacked PMOS, the gate-oxide overstress and hot-carrier degradation are avoided. Moreover, gate-tracking and floating N-well circuits are used to remove the undesirable leakage current paths. The maximum transmitting speed of the proposed I/O cell is 103/120/84 Mbps for the supply voltage of I/O cell at 5/3.3/1.8 V, respectively, given the load of 20 pF.
198

The Effects of Counterion on Intramolecular Electron-Transfer Rate for Binuclear Mixed-Valence Biferrocenium Salts

Lee, Tzon-Jyi 04 July 2000 (has links)
no
199

The study of the enzymes of the mixed function oxidase¡]MFO¡^system and its relation to the imposex of Thais spp.

Yang, Wei-Ching 22 August 2000 (has links)
Induction imposex of gastropod snails by organotins has been reported worldwide. However, the relationship between imposex and detoxification capability is not well studied in molluscs. In the present study, the relationship between the mixed function oxidase (MFO) system and the degree of imposex in drills Thais spp. was investigated. Thais clavigera, T. rufotincta and T. sp. were collected from the west coast of Taiwan. The degree of imposex was determined by percent imposex, relative penis size (RPS) and vas defenes sequence (VDS). Enzymes of cytochrome P450, NADPH-cytochrome c reductase, EROD¡]7-ethoxyresorufin-O-deethylation¡^ and cytochrome P420 (an inactive form of cytochrome P450) in the MFO system were examined. In the three Thais species, the degrees of imposex expressed as percent imposex, RPS and VDS were 71-100%, 8.8-62.5% and 0.7-2.5, respectively. Contents of cytochrome P450 and cytochrome P420 were 0.043-0.097 nmol/mg protein and 0.129-0.296 nmol/mg protein, respectively. The activity of NADPH-cytochrome c reductase was in the range of 1.52-6.73 nmol/min/mg protein. The activity of EROD was not detected. Negative trends between the degree of imposex and the contents of cytochrome P450 and cytochrome P420 were found in all the Thais species. And, a positive trend betweed the degree of imposex and the activity of NADPH-cytochrome c reductase was also observed. Based on the results, it is suggested that the induction of imposex was possibly due to the imbalance of steroid hormone metabolism caused by the inhibition of cytochrome P450 activity.
200

Implementation and Design of a Cycle-Efficient 64b/32b Integer Divider Using a Table-Sharing Method

Wang, Jun-Jie 15 June 2001 (has links)
The first topic of this thesis is a mixed radix-16/8/4/2 64b/32b integer divider which uses a variety of techniques, including operand scaling, table partitioning, and table sharing, to increase performance without paying the cost of increasing complexity. The second topic is a noise immune address transition detector¡]ATD¡^circuit. We employ a simple feedback loop to stabilize the generated CS¡]chip select¡^signal and two delay cells to dynamically adjust the width of the CS strobe.

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