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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.
161

Contributions to the molecular genetics of the Narrow-leaf Lupin (Lupinus augustifolius L.) : mapping, marker development and QTL analysis

Boersma, Jeffrey George January 2007 (has links)
[Truncated abstract] Narrow-leaf lupin (Lupinus angustifolius L.) was first recorded as having been introduced into Germany during the mid-19th century for use as green manuring and as fodder crops. However, it was not until post World-War I that there was any serious attempt to domesticate the species. Since that time several key domestication genes have been incorporated to enable the species to be grown as a crop over a range of climates, harvested as a bulk commodity and, the seed used for both animal and human consumption. However, the recent domestication of this species has seen a rather limited use of wild germplasm largely as a result of the difficulty in retaining these key domestication genes. To make the task of retaining these genes manageable, it was decided to resort to molecular technology. A mapping population of F8 derived recombinant inbred lines (RILs) has previously been established by the Department of Agriculture and Food, Western Australia, from a cross between a domesticated breeding line 83A:476 and a wild type P27255 in narrow-leaf lupin. The parents together with 89 RILs (of a population of 115) were subjected to DNA fingerprinting using microsatelliteanchored fragment length polymorphism (MFLP) to rapidly generate DNA markers for construction of a linkage map. Five hundred and twenty two unique markers of which 21% were co-dominant, were generated and mapped. Phenotypic data for the domestication traits: mollis (soft seeds), leucospermus (white flower and seed colour); Lentus (reduced pod-shattering), iucundis (low alkaloid), Ku (early flowering) and moustache pattern on seed coats; were included. Three to 7 molecular markers were identified within 5 cM of each of these domestication genes. The anthracnose resistance gene Lanr1 was also mapped. Linkage groups were constructed using MapManager version QTXb20, resulting in 21 linkage groups consisting of 8 or more markers. ... Five pairs of QTLs were found to be involved in epistasis, 2 of these having an effect on early vigour and another 3 influencing the time to opening of the first florets. Variation explained for each trait ranged from 28% for seed size, to 88% for days to flowering. We showed that it was possible to use this data to predict genotypes of superior progeny for these traits under Mediterranean conditions. QTL regions were compared on a second published linkage map and regions of conserved synteny with the model legume Medicago truncatula high-lighted. The work presented in this thesis demonstrates the importance of tight linkage between markers and genes of interest. It is especially important when dealing with genetically diverse material as found in the wild. One of the main problems faced by molecular scientists is the phenomenon known as linkage disequilibrium in marker populations caused by either small population size or 4 insufficient opportunity for recombination. This frequently results in the development of markers with little or no application outside of the population in which it was developed. Although the relatively small size of the population used in this study exposes it to such constraints, in this case excellent and valuable results were achieved in developing useful markers to at least 3 of the domestication traits within a relatively short time period of less then 4 years.
162

Personality Traits and Career Decidedness: An Empirical Study of University Students

Smith, Ryan M. 01 May 2011 (has links)
Research on vocational behavior has made progress in identifying broad personality traits associated with career indecision; however, important questions remain unanswered about the temporal stability of relationships between broad personality traits and Career Decidedness (CD), and about the role of narrow personality traits as predictors of CD, both of which were addressed in this longitudinal field study. A total of 2,046 undergraduate students completed an online personality inventory and CD questionnaire. A sub-group (N=267) responded to a follow-up questionnaire seven months later. Results indicated, as hypothesized, that CD correlated positively with the broad (Big Five) personality traits, openness, conscientiousness, and agreeableness. However, CD did not correlate as expected with the broad trait, extraversion, and correlated significantly and inversely with the broad trait, neuroticism, only for low-achievement students. Results showed that the narrow traits of optimism and work drive correlated significantly and positively with CD, and that these narrow traits accounted for more variance in CD (11.2%) than broad traits (.5%). CD correlated positively with chronological age, as predicted. However, Career Decidedness only increased through the first three of four years of college, and contrary to predictions, showed a non-significant decline in the senior year. In an unexpected finding based only on the sub-group who completed the second set of questionnaires, the relationship of personality and CD strengthened over the 7-month span of this study, yet instability within CD warrants caution. Results suggest questions for future research and implications for practice in vocational psychology.
163

Kinematics of the Narrow-Line Regions in the Seyfert Galaxies NGC 4151 and NGC 1068

Das, Varendra 03 August 2006 (has links)
We present a study of high-resolution long-slit spectra of the Narrow-Line Regions (NLRs) of NGC 4151 (a Seyfert 1 galaxy) and NGC 1068 (a Seyfert 2 galaxy) obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). The spectra were retrieved from the Multimission Archive at Space Telescope (MAST) and were obtained from five and seven orbits of HST time resulting in five and seven parallel slit configurations at position angles of 52 degrees and 38 degrees for NGC 4151 and NGC 1068 respectively. The spectra have a spatial resolution of 0.2 arcsecond across and 0.1 arcsecond along each slit. Observations of [O III] emission from the NLRs were made using the medium resolution G430M grating aboard HST. The spectral resolving power of the grating, R~9000, resulted in the detection of multiple kinematic components of the [O III] emission line gas along each slit. Radial velocities of the components were measured using a Gaussian fitting procedure. Biconical outflow models were generated to match the data and for comparison to previous models done with lower dispersion observations. The general trend is an increase in radial velocity roughly proportional to distance from the nucleus, followed by a linear decrease after roughly 100 pc. This is similar to that seen in other Seyfert galaxies, indicating common acceleration and deceleration mechanisms. The full-width at half-maximum (FWHM) of the emission lines reaches a maximum of 1000 km/s near the nucleus, and generally decreases with increasing distance to about 100 km/s in the extended narrow-line region (ENLR), starting at about 400 pc from the nucleus. In addition to the bright emission knots, which generally fit our model, there are faint high velocity clouds that do not fit the biconical outflow pattern of our kinematic model. A comparison of our observations with high-resolution radio maps shows that the kinematics of the faint NLR clouds may be affected by the radio lobes that comprise the inner jet. However, the bright NLR clouds show a smooth transition across the radio knots in radial velocity and velocity dispersion plots and remain essentially undisturbed in their vicinity, indicating that the radio jet is not the principal driving force on the outflowing NLR clouds. A dynamical model was developed for NGC 1068; it includes forces of radiation pressure, gravity, and drag due an ambient medium, simultaneously acting on the NLR clouds. The velocity profile from this model was too steep to fit the data, which show a more slowly increasing velocity profile. Gravity alone was not able to slow down the clouds but with the drag forces included, the clouds could slow down, reaching systemic velocities at distances that depend on the column densities of the NLR gas and density of the intercloud medium. A biconical model using the geometric parameters from our kinematic fit, and the velocity law from the dynamic fit, was used to match the data. The resulting dynamic model represented a poor fit to the data, indicating the need for additional dynamical considerations.
164

Tillförlitligheten i beräknade dimensionerande flöden i två mindre vattendrag med trånga sektioner / The reliability of estimated design floods in two small streams with narrow sections

Carlsson, Lisa January 2013 (has links)
I Sverige finns idag en vedertagen metod för att bestämma dimensionerande flöde för dammanläggningar. De teoretiska beräkningarna av dimensionerande flöde för dammanläggningar tillhörande flödesdimensioneringsklass I baseras på HBV-modellen, en begreppsmässig hydrologisk beräkningsmodell som beskriver samspelet mellan de meteorologiska och hydrologiska förhållanden som råder inom ett avrinningsområde. Begreppsmässiga hydrologiska modeller baseras på vattenbalansen och används för att bestämma tillrinning till vattendrag, sjöar eller andra vattenförekomster. Vid hydrologisk modellering med begreppsmässiga modeller tas ingen explicit hänsyn till vattendragets geometri. Trånga sektioner i naturliga vattendrag kan hindra vattnets framfart och orsaka dämning uppströms den trånga sektionen. Till följd av det kan en del av flödestoppen kvarhållas i terrängen och därmed dämpas och fördröjas. Hydrauliska modeller beskriver vattnets flöde genom vattendraget. Högupplöst höjddata utgör grunden i en hydraulisk modell och vid hydraulisk modellering tas således hänsyn till avrinningsområdets topografi såväl som vattendragets batymetri. Syftet med detta examensarbete var att analysera tillförlitligheten i beräknade dimensionerande flöden framtagna enligt Flödeskommitténs Riktlinjer för bestämning av dimensionerande flöden för dammanläggningar. Genom att upprätta hydrauliska modeller över två specifika vattendragssträckor som berörs av trånga sektioner kunde det undersökas huruvida de trånga sektionerna orsakar någon flödesdämpning samt om flödesdämpningen beror av storleken på vattenflödet. De områden som var föremål för denna studie var en delsträcka av Övre Lagan samt en del av Bolmån som är Lagans största tillflöde. Resultaten visade att flödestopparna dämpades och att det var de trånga sektionerna som orsakade den huvudsakliga flödesdämpningen. Vidare visade resultaten att den relativa dämpningen beror av storleken på inflödet i de hydrauliska modellerna. Den relativa dämpningen av det dimensionerandet flödet vid Övre Lagan var marginell, 1,2 % respektive 2,0 %, medan den vid Bolmån uppgick till 6,7 %. Det faktum att de dimensionerande flödena emellertid dämpades i de båda fallen bör vara skäl nog att se över metoden för bestämmandet av dimensionerande flöden för dammanläggningar tillhörande flödesdimensioneringsklass I och undersöka huruvida det är möjligt att innefatta hydraulisk modellering i den idag vedertagna beräkningsmetodiken. / In Sweden there is currently an accepted method for determining the design floods for dams which is described in The Swedish Design Flood Guidelines. The theoretical calculations of the design floods for dams associated with Flood Design Category I are based on the HBV model, a conceptual hydrological model that describes the interaction between the meteorological and hydrological conditions within a basin. Conceptual hydrological models are based on the water balance and are used to determine runoff to streams, lakes or other bodies of water. Conceptual hydrological models do not take explicit account for the geometry of the watercourse. Narrow sections in natural streams may prevent water flow and cause impoundment upstream from the narrow section. Following that, a part of the flow peak can be retained in the terrain and thereby attenuated and delayed. Hydraulic models describe the flow of water through the watercourse. High resolution elevation data is the foundation of a hydraulic model and hydraulic models thus take into account the basin topography as well as the watercourse bathymetry. The objective of this study was to analyze the reliability of design floods that have been determined according to The Swedish Design Flood Guidelines. By establishing hydraulic models of two specific streams affected by narrow sections it could be examined whether the narrow sections cause flow attenuation and whether the flow attenuation depends on the size of the water flow. The areas which were the subject of this study were a subsection of River Lagan and part of River Bolmån, which is River Lagan’s largest tributary. The results of the hydraulic model simulations showed that the flow peaks were attenuated and that it was the narrow sections that caused the main flow attenuation. Furthermore, the results showed that the relative attenuation depends on the size of the inflow in the hydraulic models. The relative attenuation of the design floods was 1.2 % and 2.0 % at River Lagan and 6.7 % at River Bolmån. The relative attenuation of the design flood was thus marginal at River Lagan. The fact that the design floods nevertheless were attenuated at both areas which were the subject of this study should be reason enough to review the method for the determination of design floods for dams associated with Flood Design Category I and examine whether it is possible to include hydraulic modeling in today’s conventional calculation methodology.
165

Blind Adaptive Multiuser Detection for DS-CDMA System Based on Sliding Window RLS Algorithm

Pan, Wei-Hung 10 September 2004 (has links)
Direct sequence code division multiple access (DS-CDMA) technique is one of the significant multiplexing technologies used in wireless communication services. In the DS-CDMA framework, all users have been assigned distinct signature code sequence to achieve multiple accesses within the same frequency band, and allow signal separating at the receiver. Under multipath fading environment with near-far effect, the current CDMA systems employed the RAKE receiver, to enhance the system performance. It is known that if training data is available the minimum mean squares error (MMSE) multiuser receiver, in which the average power of the receiver output is minimized subject to appropriate constraints, could be obtained by solving directly by the constrained Wiener estimation solution. However, if this is not the case, the blind multiuser receiver is an alternative approach to achieve desired performance closed to the one with the MMSE approach. In this thesis, based on the max/min criterion, the blind multiuser receiver, with linear constraints, is devised. Here constraint equations are written in parametric forms, which depend on the multipath structure of the signal of interest. Constraint parameters are jointly optimized with the parameters of the linear receiver to obtain the optimal parameters. In consequence, the sliding window linearly constrained RLS (SW-LC-RLS) algorithm is employed to implement the optimal blind receiver, with max/min approach. This new proposed scheme can be used to deal with multiple access interference (MAI) suppression for the environments, in which the narrow band interference (NBI) due to other systems is joined suddenly to the DS-CDMA systems, and having serious near-far effect. Under such circumstance, the channel character due to the NBI and near-far effect will become violent time varying, such that the conventional LC-RLS algorithm as well as LC-LMS algorithms could not perform well. Via computer simulation it confirms that our proposed scheme has better capability for MAI suppression in DS-CDMA systems than other existing schemes, and is more robust against the NBI and near-far problems.
166

Blind Adaptive DS-CDMA Receivers with Sliding Window Constant Modulus GSC-RLS Algorithm Based on Min/Max Criterion for Time-Variant Channels

Chang, Shih-chi 26 July 2006 (has links)
The code division multiple access (CDMA) system implemented by the direct-sequence (DS) spread spectrum (SS) technique is one of the most promising multiplexing technologies for wireless communications services. The SS communication adopts a technique of using much wider bandwidth necessary to transmit the information over the channel. In the DS-CDMA system, due to the inherent structure interference, referred to as the multiple access interference (MAI), the system performance might degrade. Next, for DS-CDMA systems over frequency-selective fading channels, the effect of inter symbol interference (ISI) will exist, such that a multiuser RAKE receiver has to be employed to combat the ISI as well as MAI. Since, in practical wireless communication environment, there may have several communication systems operated in the same area at the same time. In this thesis, we consider the environment of DS-CDMA systems, where the asynchronous narrow band interference (NBI) due to other systems is joined suddenly to the CDMA system. In general, when a system works in a stable state with adaptive detectors, a suddenly joined NBI signal will cause the system performance to be crash down. Under such circumstance, the existing conventional adaptive RAKE detectors may not be able to track well for the rapidly sudden changing NBI associated with the problems of ISI and MAI. It is known that the adaptive filtering algorithms, based on the sliding window linear constrained recursive least squares (SW LC-RLS), is very attractive to a violent changing environment. The main concern of this thesis is to propose a novel sliding window constant modulus RLS (SW CM-RLS) algorithm, based on the Min/max criterion, to deal with the NBI for DS-CDMA system over multipath channels. For simplicity and having less system complexity the generalized side-lobe canceller (GSC) structure is employed, and is referred to as the SW CM-GSC-RLS algorithm. The aim of the SW CM-GSC-RLS algorithm is used to alleviate the effect of NBI. It has the advantages of having faster convergence property and tracking ability, and can be applied to the environment in which the NBI is suddenly joined to the system under the effect of channel mismatch to achieve desired performance. At the end of this thesis, we extend the idea of the proposed algorithm to the space-time DS-CDMA RAKE receiver, in which the adaptive beamformer with temporal domain DS-CDMA receiver is employed. Via computer simulation results, we show that our new proposed schemes outperform the conventional CM GSC-RLS algorithm as well as the GSC-RLS algorithm (the so-called LCMV approach), in terms of mean square error of estimating channel impulse response, output signal to interference plus noise ratio and bit-error-rate.
167

NUMERICAL AND EXPERIMENTAL STUDIES OF NATURAL CONVECTIVE HEAT TRANSFER FROM VERTICAL AND INCLINED NARROW FLAT PLATES AND SHORT CYLINDERS

KALENDAR, ABDULRAHIM 08 November 2011 (has links)
Natural convective heat transfer from flat plates and short cylinders inclined at an angle to the vertical in laminar and transition flow regions with isothermal or constant heat flux conditions have been numerically and experimentally studied. When the width of the plate is relatively small compared to its height, i.e., the plate is narrow, the heat transfer rate can be considerably greater than that predicted by these two-dimensional flow results. When the narrow plate is inclined to the vertical, pressure changes normal to the plate surface arise and these pressure changes can alter the nature and the magnitude of the edge effects. When two narrow inclined rectangular flat plates of the same size separated vertically or horizontally, the flow interaction between these heated plates can have a significant effect on the heat transfer. When relatively small square and circular cylinders with exposed top surfaces inclined to the vertical are used, the interaction of the flow over the surfaces that make up the cylinder and inclination angle have, in general, a considerable effect on the magnitude of the mean heat transfer rate and on the nature of the flow over the cylinder surfaces. In the present numerical studies it has been assumed that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces, this having been treated using the Boussinesq approach. The numerical solution was obtained by numerically solving the full three-dimensional form of the governing equations, these equations being written in dimensionless form. The solution was obtained using a commercial CFD code, FLUENT. Results were only obtained for a Prandtl number of 0.7; this being approximately the value of air. In the experimental studies, the average heat transfer rates from cylinders were determined by the transient method, which involves heating the model and then measuring its temperature-time variation while it cools. The average heat transfer rates from the flat plates were determined using a steady state method, which basically involved electrically heating the plate. The tests were carried out inside a large enclosure. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2011-06-27 19:27:45.724
168

A Fire Simulation Model for Heterogeneous Environments Using the Level Set Method

Lo, Shin-en 01 January 2012 (has links)
Wildfire hazard and its destructive consequences have become a growing issue around the world especially in the context of global warming. An effective and efficient fire simulation model will make it possible to predict the fire spread and assist firefighters in the process of controlling the damage and containing the fire area. Simulating wildfire spread remains challenging due to the complexity of fire behaviors. The raster-based method and the vector-based method are two major approaches that allow one to perform computerized fire spread simulation. In this thesis, we present a scheme we have developed that utilizes a level set method to build a fire spread simulation model. The scheme applies the strengths and overcomes some of the shortcomings of the two major types of simulation method. We store fire data and local rules at cells. Instead of calculating which are the next ignition points cell by cell, we apply Huygens' principle and elliptical spread assumption to calculate the direction and distance of the expanding fire by the level set method. The advantage to storing data at cells is that it makes our simulation model more suitable for heterogeneous fuel and complex topographic environment. Using a level set method for our simulation model makes it possible to overcome the crossover problem. Another strength of the level set method is its continuous data processing. Applying the level set method in the simulation models, we need fewer vector points than raster cells to produce a more realistic fire shape. We demonstrate this fire simulation model through two implementations using narrow band level set method and fast marching method. The simulated results are compared to the real fire image data generated from Troy and Colina fires. The simulation data are then studied and compared. The ultimate goal is to apply this simulation model to the broader picture to better predict different types of fires such as crown fire, spotting fires, etc.
169

Investigation Of Air Bubble Motion In Water Through A Vertical Narrow Rectangular Channel By Using Image Processing Techniques

Ozdemir, Sancak 01 August 2005 (has links) (PDF)
This thesis presents the study of air bubble motion in stagnant water and in upward flowing water through a vertical narrow rectangular channel of 2.1X66.5 mm cross section by using image processing and analyzing techniques. The investigated bubble size range is 2 - 70 mm in area equivalent bubble diameter and mean water flow velocity is 0-25 cm/s. This study focuses on the quantitative assessment of bubble size (perimeter, area, volume, width and height), shape, path and rising velocity. The observed bubble shapes consist of circular, ellipse, ellipse wobbling, hat wobbling, cap-hat, cap and cap-bullet types. Ellipse wobbling and hat wobbling type bubble region show transition from ellipsoidal to circular cap region. The results of the ellipse bubble tests were compared with the rise velocity correlation of ellipsoidal bubbles in infinite medium and an empirical correlation for two dimensional ellipse bubbles was obtained. The cap bubble rise velocities measured in this study were compared with the correlations in literature and a new empirical correlation which is different from those given in the literature was obtained from the experimental results of this study. The trends of the cap bubble deformation which is defined as bubble height to bubble width ratio, for various water streams are almost similar in behavior. Therefore, a correlation was obtained from the measured cap bubble deformation values in water stream. The experimental results show that the bubble relative velocity under co-current flow conditions for area equivalent bubble diameter to channel width ratio, &amp / #955 / ae&lt / 0.6 is less than that under stagnant water condition. After bubble shapes reach to the slug type (&amp / #955 / ae &amp / #8805 / 0.6), relative bubble velocities pass over the terminal bubble velocities in stagnant water. If the water velocity is increased further, the bubble relative velocity increases in the slug bubble region. Rising velocities of slug bubbles were analyzed using the experimental data and a new correlation for slug bubble rise velocity was proposed for flowing water condition.
170

A Narrow Band Level Set Method for Surface Extraction from Unstructured Point-based Volume Data

Rosenthal, Paul, Molchanov, Vladimir, Linsen, Lars 24 June 2011 (has links) (PDF)
Level-set methods have become a valuable and well-established field of visualization over the last decades. Different implementations addressing different design goals and different data types exist. In particular, level sets can be used to extract isosurfaces from scalar volume data that fulfill certain smoothness criteria. Recently, such an approach has been generalized to operate on unstructured point-based volume data, where data points are not arranged on a regular grid nor are they connected in form of a mesh. Utilizing this new development, one can avoid an interpolation to a regular grid which inevitably introduces interpolation errors. However, the global processing of the level-set function can be slow when dealing with unstructured point-based volume data sets containing several million data points. We propose an improved level-set approach that performs the process of the level-set function locally. As for isosurface extraction we are only interested in the zero level set, values are only updated in regions close to the zero level set. In each iteration of the level-set process, the zero level set is extracted using direct isosurface extraction from unstructured point-based volume data and a narrow band around the zero level set is constructed. The band consists of two parts: an inner and an outer band. The inner band contains all data points within a small area around the zero level set. These points are updated when executing the level set step. The outer band encloses the inner band providing all those neighbors of the points of the inner band that are necessary to approximate gradients and mean curvature. Neighborhood information is obtained using an efficient kd-tree scheme, gradients and mean curvature are estimated using a four-dimensional least-squares fitting approach. Comparing ourselves to the global approach, we demonstrate that this local level-set approach for unstructured point-based volume data achieves a significant speed-up of one order of magnitude for data sets in the range of several million data points with equivalent quality and robustness.

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