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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.
81

Genetic changes in natural populations caused by the release of cultured fishes [electronic resource] / by Michael Dominic Tringali.

Tringali, Michael D. January 2003 (has links)
Includes vita. / Title from PDF of title page. / Document formatted into pages; contains 241 pages. / Thesis (Ph.D.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Genetic changes likely occur in wild fish populations as a consequence of interactions with cultured fish, but to what extent do those changes threaten the maintenance of natural genetic diversity and population viability? Following a review and categorization of numerous processes suspected of being agents of post-release genetic change in recipient wild populations (Chapter 1), I focus on risks relating to the magnitude and duration of releases -- but with a twist. That is, I assume that the mean fitness of released, cultured individuals does not differ from that of the recipient natural population. Throughout, attention is devoted to potential post-release changes in inbreeding (NeI) and variance (NeV) effective population sizes -- indicators of expected rates of population-level change in inbreeding and drift variance, respectively. The reductive effect that large-scale releases exert on NeI in recipient populations can be significant. / ABSTRACT: The effect is shown to be a threshold process (Chapter 2) and thus suggestive of an approach for determining risk-adverse stocking (or release) rates. This approach is utilized in Chapter 3, which describes genetic recommendations for an incipient marine stocking program. Several discordant contemporary NeI models are examined mathematically and by computer simulation (Chapter 4). I show that certain published results pertaining to the effect of multiple paternity on NeI are erroneous; a general model is described which accounts for inbreeding and relatedness in and among parents. That model is utilized in an empirical study of gene correlation in a hatchery cohort (Chapter 5). Propagation-related causes of reductions in NeI are also investigated in this cohort. / ABSTRACT: Finally, extending mutational meltdown theory to accommodate fluctuating population sizes and recessive selective effects, I show that when large reductions in NeV occur (such as those that accompany admixtures of cultured and wild fish), the expected time to population inviability is significantly reduced (Chapter 6). Although a more comprehensive theoretical approach is needed, a precautionary inference may be drawn -- aquaculture-induced reductions in Ne, even though they may be transient, can lead to adverse genetic impacts. Avoidance of Ne-reductions cannot be accomplished, in a practical sense, without considering the stocking or release rates of cultured fish. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
82

Film in the classroom [electronic resource] : toward a more effective pedagogy / by Jonathan Godwin.

Godwin, Jonathan. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 130 pages. / Thesis (M.A.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The postmodern critique has effectively called on anthropologists to reevaluate ethnographic authority when representing others. However, what is often found lacking in this criticism is an exploration of the ways in which audiences interpret anthropological knowledge. One crucial area that can be easily researched is audience reception of film in introductory anthropology classes. As professors of anthropology increasingly rely on film for illustrating anthropological concepts, we must have an understanding of how this medium is interpreted by student audiences. Film's ability to convey complex information without additional contextualization has yet to be substantiated and previous research has indicated that visual communication's messages may easily be misinterpreted by audiences. Furthermore, there is evidence that films, if used improperly, may perpetuate students' negative impressions of cultures other than their own. / ABSTRACT: Finally, any research into audience reception of film in the classroom must consider the factors outside the class that shape an audience's interpretations of films. The research presented in this thesis looks at the use of film in teaching introductory classes at USF. The goal is to connect the students' interpretations of films to the contextual factors of the classroom as well as considering the larger influence that the surrounding media culture in everyday life has on the interpretation of film in the classroom. In this way, the research strives to offer recommendations that may improve the effectiveness of using film when teaching introductory anthropology classes. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
83

An assessment of paired similarities and card sorting [electronic resource] / by Theodore James Dwyer.

Dwyer, Theodore James. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 64 pages. / Thesis (M.A.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Alcohol expectancies have been shown to be predictive of risk for alcohol problems. Experimental research studies have challenged participants' expectancies with the end result demonstrating a mediational effect on participant drinking. Cognitive research using priming and word recognition tasks have led to the theory that expectancies operate in an associative network. Using dissimilarities information this network has been mapped using multidimensional scaling. The current techniques for collecting dissimilarities information directly in alcohol expectancy research has been limited to the use of the paired comparisons tasks. In order to investigate the utility of a different similarities task a comparison was made between a card sorting task and paired comparisons. / ABSTRACT: The overall comparisons of matrices and Individual Difference Scaling (INDSCAL; Carroll & Chang, 1970) results followed the expected trends and generally supported the hypotheses that the two methods would provide essentially the same information. However, a possible method effect for gender was observed. The method effect was seen when comparing across methods within the females dichotomized by drinker category. Further studies are necessary to replicate these findings and to attempt to identify which method has the effect. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
84

The fleeting effects of retrieval cue attributes in the PIER2 memory model [electronic resource] / by Amie L. Wilbanks.

Wilbanks, Amie L. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 43 pages. / Thesis (M.A.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Processing Implicit and Explicit Representations (PIER2) is a model of memory that makes predictions about memory performance based on the interaction of known and newly acquired information by studying how implicitly activated associates affect episodic memory. Nelson and Zhang (2000) found a significant effect of cue connectivity in a multiple regression analysis of the variables known to affect cued recall, but at that time no manipulational experiments had studied the cue connectivity effect in the laboratory. The present paper presents a series of three experiments designed to investigate the effect of cue connectivity in the context of the PIER2 memory model to determine the importance of this variable in the prediction of cued recall. / ABSTRACT: Results of the experiments were inconsistent, and a revised regression analysis performed on an updated version of Nelson and Zhang's (2000) cued recall database indicated that cue connectivity was no longer a significant predictor of cued recall performance. It was concluded that PIER2's equations do not need to be modified to include the influence of retrieval cue attributes. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
85

Characterization and generation of streaming video traces [electronic resource] / by John N Shahbazian.

Shahbazian, John N. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 68 pages. / Thesis (M.S.C.S.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: This thesis describes two methods collectively called Time Series Generation (TSG) that can be used to generate time series inputs modeling packet loss to test IP-based streaming video software. The TSG methods create packet loss models that recreate the mean, variance, and autocorrelation signatures of an actual trace. The synthetic packet loss traces can have their inherent statistics altered, thus allowing for thorough testing of video software in ways that could not be done on actual networks. The two methods comprising TSG, which are individually called the primary and secondary method, use the principle of iterated uniformity to create a time series that attempts to match mean, variance, and autocorrelation. The two methods differ in their approach to generating autocorrelation. This leads to trade-offs between the two. The TSG methods are embodied in a software program called TSGen. / ABSTRACT: An evaluation of TSGen is conducted, including a comparison with the well-known Autoregressive-To-Anything Generation algorithm (ARTAGEN) method and tool. The details of capturing packets and parsing video frame counts from packet streams are explained and demonstrated. Sixteen video stream traces were collected from a variety of sources and used to evaluate TSGen. Synthetic traces are generated for the sixteen original traces and both their summary statistics and autocorrelation signatures are compared against the originals. One of the sixteen traces is also compared against a synthetic trace generated using the ARTAGEN tool. Twelve out of the sixteen synthetic traces when compared to the actual traces had Least Square Error (LSE) values under 0.1, three were under 0.4, and the remaining one was under 1.1. / ABSTRACT: Nine synthetic traces had their percent error differences between the mean and variance of the synthetic and actual traces below 5%, one was below 7%, four were under 18%, and the two remaining were at 41%. TSGen is able to effectively model autocorrelation, mean, and variance. Additional intangible benefits of TSG include adjustable run time for the matching process, with longer run time equating to better accuracy, and a simple theoretical model that was easily implemented. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
86

A mathematical model for colloidal aggregation [electronic resource] / by Colleen S. O'Brien.

O'Brien, Colleen S. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 313 pages. / Thesis (M.S.Ch.E.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The characterization of fine particles is an area of immense significance to many industrial endeavors. It has been estimated that 70% of all industrial processes deal with fine particles at some point in the process. A natural phenomenon occurring in these processes is colloidal aggregation. This study examines aggregation in colloidal systems in order to characterize, examine, and control this occurrence in industrial processes. The study of particle aggregation has been broken into many different areas, such as collision mechanisms, interaction energy etc, but a complete model that integrates these different aspects has never been fully realized. A new model is required to accurately predict the aggregation behavior of colloidal particles. In this work, a new model is developed that integrates Smoluchowski kinetics, total interaction energy between particles, and stability ratios for perikinetic and orthokinetic collision mechanisms. / ABSTRACT: The total particle interaction energy necessary for the calculation of stability ratios is represented by the summation of electrostatic and van der Waals interactions. The electrostatic interactions are modeled using DLVO theory, the linear Poisson-Boltzmann equation, and a numerical solution for the non-linear Poisson-Boltzmann Equation, while the van der Waals interactions are represented by Hamaker theory. The mathematical model is solved using an adjustable discretion technique, which is tested against a specific analytic solution, and yields an assessment of the error intrinsic in the discretization method. The basis of the mathematical model is a population balance framework. The model developed in this study is general in many respects, but could be readily applied to many different aggregation systems with minor modification. / ABSTRACT: A comparison of the mathematical model with previous experiments conducted by Scott Fisher (1998) is carried out for the perikinetic and orthokinetic transport-limited aggregation regimes. The fractal nature of solid-sphere aggregates is considered when comparing the mathematical model predictions with experimental measurements. The previous experiments that are used for comparison utilized polystyrene particles ranging from 100 nm to 500 nm in initial diameter, several initial particle concentrations, and various stirring rates. Zeta potential measurements are presented in order to set the range of transport-limited aggregation. An assessment of the results of the mathematical model with the experimental results show good agreement for transport-limited aggregation within the perikinetic and orthokinetic transport-limited aggregation, with average particle sizes ranging from 100 nm to well over 2 microns. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
87

Design and fabrication of multi-dimensional RF MEMS variable capacitors [electronic resource] / by Hariharasudhan T. Kannan.

Kannan, Hariharasudhan T. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 88 pages. / Thesis (M.S.E.E.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: In this work, a multi dimensional RF MEMS variable capacitor that utilizes electrostatic actuation is designed and fabricated on a 425um thick silicon substrate. Electrostatic actuation is preferred over other actuation mechanisms due to low power consumption. The RF MEMS variable capacitor is designed in a CPW topology, with multiple beams supported (1 - 7 beams) on a single pedestal. The varactors are fabricated using surface micromachining techniques. A 1um thick silicon monoxide (Er - 6) is used as a dielectric layer for the varactor. The movable membrane is suspended on a 2.5um thick electroplated gold pedestal. The capacitance between the membrane and the bottom electrode increases as the bias voltage between the membrane and the bottom electrode is increased, eventually causing the membrane to snap down at the actuation voltage. For the varactors designed herein, the actuation voltage is approximately 30 - 90V. / ABSTRACT: Full-wave electromagnetic simulations are performed from 1 - 25GHz to accurately predict the frequency response of the varactors. The EM simulations and the measurement results compare favorably. A series RLC equivalent circuit is used to model the varactor and used to extract the parasitics associated with the capacitor by optimizing the model with the measurement results. The measured capacitance ratio is approximately 12:1 with a tuning range from 0.5 - 6pF. Furthermore, the measured S-parameter data is used to extract the unloaded Q of the varactor (at 1GHz) and is found to be 234 in the up state and 27 in the down state. An improved anodic bonding technique to bond high resistivity Si substrate and low alkali borax glass substrate that finds potential application towards packaging of MEMS varactors is investigated. To facilitate the packaging of the varactors the temperature is maintained at 400°C. The bonding time is approximately 7min at an applied voltage of 1KV. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
88

A VLSI architecture for Rijndael, the advanced encryption standard [electronic resource] / by Naga M. Kosaraju.

Kosaraju, Naga M. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 93 pages. / Thesis (M.S.Cp.E.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The increasing application of cryptographic algorithms to ensure secure communications across virtual networks has led to an ever-growing demand for high performance hardware implementations of the encryption/decryption methods. The inevitable inclusion of the cryptographic algorithms in network communications has led to the development of several encryption standards, one of the prominent ones among which, is the Rijndael, the Advanced Encryption Standard. Rijndael was chosen as the Advanced Encryption Standard (AES) by the National Institute of Standard and Technology (NIST), in October 2000, as a replacement for the Data Encryption Standard (DES). This thesis presents the architecture for the VLSI implementation of the Rijndael, the Advanced Encryption Standard algorithm. Rijndael is an iterated, symmetric block cipher with a variable key length and block length. The block length is fixed at 128 bits by the AES standard [4]. / ABSTRACT: The key length can be designed for 128,192 or 256 bits. The VLSI implementation, presented in this thesis, is based on a feed-back logic and allows a key length specification of 128-bits. The present architecture is implemented in the Electronic Code Book(ECB) mode of operation. The proposed architecture is further optimized for area through resource-sharing between the encryption and decryption modules. The architecture includes a Key-Scheduler module for the forward-key and reverse-key scheduling during encryption and decryption respectively. The subkeys, required for each round of the Rijndael algorithm, are generated in real-time by the Key-Scheduler module by expanding the initial secret key. The proposed architecture is designed using the Custom-Design Layout methodology with the Cadence Virtuoso tools and tested using the Avanti Hspice and the Nanosim CAD tools. / ABSTRACT: Successful implementation of the algorithm using iterativearchitecture resulted in a throughput of 232 Mbits/sec on a 0.35[mu] CMOS technology. Using 0.35[mu] CMOS technology, implementation of the algorithm using pipelining architecture resulted in a throughput of 1.83 Gbits/sec. The performance of this implementation is compared with similar architectures reported in the literature. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
89

Assessing the reproducibility of coral-based climate records [electronic resource] : a multi-proxy replication test using three Porites lutea coral heads from New Caledonia / by Christie L. Stephans.

Stephans, Christie L. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 93 pages / Thesis (M.S.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Coral-based climate studies commonly use elemental ratios and stable isotopes of coral skeletons to address seawater temperature and hydrologic balance issues in the tropical surface oceans. Replication, or cross-checking, a standard technique used to assess the fidelity of proxy records in paleoclimatology has not been widely applied in coral-based climate studies, primarily because of the time and cost associated with generating multiple records from a single reef site. Modern and paleoclimate reconstructions based on a single proxy-coral record from a site may contain errors if individual corals from the same reef record different geochemical signals. In this study we perform a replication test using elemental ratios and stable isotopes in three Porites corals from New Caledonia. / ABSTRACT: The reef complex offshore Amédée Island, New Caledonia is an ideal site to perform a coral replication test because instrumental sea surface temperatures (SST) and sea surface salinity measurements (SSS) have been made there for over 25 years. In this study, we compare sub-monthly resolved, geochemical variations (Sr/Ca, d18O and d13C) in three Porites lutea coral heads, located 500 m apart, with the instrumental SST and SSS records over the interval 1992-1967. The monthly coral Sr/Ca and d18O time series are well correlated to each other (r=0.86, p[.0001) and to the monthly instrumental SST record (r= -0.86, p[.0001, coral Sr/Ca to SST; r= -0.77, p[.0001, coral d18O to SST). The three, sub-monthly resolved, 30-year coral Sr/Ca-SST time series have mean SST values that agree within 0.2oC with the instrumental mean SST value. A similar comparison for the coral d18O-SST records indicate a maximum difference between predicted and observed mean SST of 0.5°C. / ABSTRACT: Analysis of the monthly climatological means also indicates that Sr/Ca-SST records closely match the instrumental SST record ±0.4°C; a similar comparison using the d18O-SST record yields an average offset of ±0.6°C between observed and predicted monthly SST. Stacking the three records to form composite Sr/Ca-SST and d18O-SST records does not appreciably improve the goodness of fit between the proxy and instrumental SST records; hence a coral-based proxy climate record from a single coral accurately reflects the observed record of climate variability at this locality. These results support the concept that high fidelity climate records can be generated using a single coral core. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.
90

Crystal engineering of binary compounds containing pharmaceutical molecules [electronic resource] / by Leslie Ann Morales.

Morales, Leslie Ann. January 2003 (has links)
Title from PDF of title page. / Document formatted into pages; contains 80 pages. / Thesis (M.S.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The synthesis or the interaction between two or more molecules is known as supramolecular chemistry. The concept of supramolecular chemistry can be applied to the design of new pharmaceutical materials affording new compositions of matter with desirable composition, structure and properties. The design of a two-molecule, or binary, compound using complementary molecules represents an example of an application of crystal engineering. Crystal engineering is the understanding of intermolecular interactions, in the context of crystal packing, in the design of new solid materials. By identifying reliable connectors through molecular recognition or self-assembly, one can build predictable architectures. / ABSTRACT: The study of supramolecular synthesis was accomplished using known pharmaceutical molecules such as Nifedipine (calcium channel blocker used for cardiovascular diseases) and Phenytoin (used as an anticonvulsant drug) and model compounds containing synthons common in pharmaceutical drugs (Crown ethers and Trimesic acid with ether linkages and carboxylic acid dimers, respectively) with complementary molecular additives. The co-crystals formed were characterized by various techniques (IR, m.p., XPD, single X-ray diffraction) and preliminary results were found to exhibit characteristics different from the parent compounds as a direct result of hydrogen bonding and self-assembly interactions. These crystalline assemblies could afford improved solubility, dissolution rate, stability and bioavailability. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

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