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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.
21

Multiscale image analysis for the automated localisation of taxonomic landmark points and the identification of species of parasitic wasp

Angel, Paul Nathan January 1999 (has links)
Automating the identification of biological specimens from 2D image data poses difficult problems given the natural variation, specimen damage and background clutter that can exist. The tools used by taxonomists tend to be manual or semi-automated, where the operator locates salient image features from which the system automatically derives taxonomic measurements for identification. Fully automating the extraction of taxonomic features and the subsequent identification task would allow for more robust and accurate identification and provide tools for users in the field who do not possess expert knowledge. This work focuses on the automatic localisation of taxonomic landmark points and the identification of species of parasitic wasps of the order Hymenoptera using SEM images of their heads. These images present significant analysis problems. Image feature extraction techniques investigated to solve this problem include deformable contour models, texture analysis and the Mallat wavelet transform. Deformable contour models perform poorly given the textural clutter in the images while texture analysis techniques introduce correlated noise into the segmented image, which can reduce landmark localisation accuracy to 25%. The wavelet transform overcomes this problem by filtering textural clutter at larger scales of analysis. A novel technique is presented which recombines the wavelet transform to create a single contour map where textural clutter is filtered out. This is based on the interaction between edge events which is calculated within a region of interest (ROI) that expands as the scale decreases. In configuring the ROI, a balance must be achieved between filtering textural clutter and eroding salient contours. The landmark localisation accuracy is directly related to this ROI expansion. This represents the main contribution to knowledge. A fast expansion at the high end of the scale range results in a landmark localisation accuracy of 95%. Applying these landmarks to a neural network classifier results in a 91% correct identification rate. This represents a significant improvement over the 65% identification rate obtained by taxonomists and is robust to landmark displacement as a result of contour erosion.
22

A Hierarchical Approach to the Analysis of Intermediary Structures Within the Modified Contour Reduction Algorithm

Wallentinsen, Kristen M 01 January 2013 (has links) (PDF)
Robert Morris’s (1993) Contour-Reduction Algorithm—later modified by Rob Schultz (2008) and hereafter referred to as the Modified Contour Reduction Algorithm (MCRA)—recursively prunes a contour down to its prime: its first, last, highest, and lowest contour pitches. The algorithm follows a series of steps in two stages. The first stage prunes c-pitches that are neither local high points (maxima) nor low points (minima). The second stage prunes pitches that are neither maxima within the max-list (pitches that were maxima in the first stage) nor minima within the min-list (pitches that were minima in the first stage). This second stage is repeated until no more pitches can be pruned. What remains is the contour’s prime. By examining how the reduction process is applied to a given c-seg, one can discern a hierarchy of levels that indicates new types of relationships between them. In this thesis, I aim to highlight relationships between c-segs by analyzing the distinct subsets created by the different levels obtained by the applying the MCRA. These subsets, or sub-csegs, can be used to delineate further relationships between c-segs beyond their respective primes. As such, I posit a new method in which each sub-cseg produced by the MCRA is examined to create a system of hierarchical comparison that measures relationships between c-segs, using sub-cseg equivalence to calculate an index value representing degrees of similarity. The similarity index compares the number of levels at which two c-segs are similar to the total number of comparable levels. I then implement this analytical method by examining the similarities and differences between thirteen mode-2 Alleluias from the Liber Usualis that share the same alleluia and jubilus. The verses of these thirteen chants are highly similar in melodic content in that they all have the same prime, yet they are not fully identical. I will examine the verses of these chants using my method of comparison, analyzing intermediary sub-csegs between these 13 chants in order to reveal differences in the way the primes that govern their basic structures are composed out.
23

CONTOUR GUIDED DISSEMINATION FOR NETWORKED EMBEDDED SYSTEMS

Chu, I-Hsine (Jack) January 2006 (has links)
No description available.
24

Contour Encoded Compression and Transmission

Nelson, Christopher B. 29 November 2006 (has links) (PDF)
As the need for digital libraries, especially genealogical libraries, continues to rise, the need for efficient document image compression is becoming more and more apparent. In addition, because many digital library users access them from dial-up Internet connections, efficient strategies for compression and progressive transmission become essential to facilitate browsing operations. To meet this need, we developed a novel method for representing document images in a parametric form. Like other “hybrid" image compression operations, the Contour Encoded Compression and Transmission (CECAT) system first divides images into foreground and background layers. The emphasis of this thesis revolves around improving the compression of the bitonal foreground layer. The parametric vectorization approach put forth by the CECAT system compares favorably to current approaches to document image compression. Because many documents, specifically handwritten genealogical documents, contain a wide variety of shapes, fitting Bezier curves to connected component contours can provide better compression than current glyph library or other codebook compression methods. In addition to better compression, the CECAT system divides the image into layers and tiles that can be used as a progressive transmission strategy to support browsing operations.
25

The Role of Melodic Contour in Linguistic Processing

Wang, Yun January 2017 (has links)
No description available.
26

A Computer Vision Tool For Use in Horticultural Research

Thoreson, Marcus Alexander 13 February 2017 (has links)
With growing concerns about global food supply and environmental impacts of modern agriculture, we are seeing an increased demand for more horticultural research. While research into plant genetics has seen an increased throughput from recent technological advancements, plant phenotypic research throughput has lagged behind. Improvements in open-source image processing software and image capture hardware have created an opportunity for the development of more competitively-priced, faster data-acquisition tools. These tools could be used to collect measurements of plants' phenotype on a much larger scale without sacrificing data quality. This paper demonstrates the feasibility of creating such a tool. The resulting design utilized stereo vision and image processes in the OpenCV project to measure a representative collection of observable plant traits like leaflet length or plant height. After the stereo camera was assembled and calibrated, visual and stereo images of potato plant canopies and tubers(potatoes) were collected. By processing the visual data, the meaningful regions of the image (the canopy, the leaflets, and the tubers) were identified. The same regions in the stereo images were used to determine plant physical geometry, from which the desired plant measurements were extracted. Using this approach, the tool had an average accuracy of 0.15 inches with respect to distance measurements. Additionally, the tool detected vegetation, tubers, and leaves with average Dice indices of 0.98, 0.84, and 0.75 respectively. To compare the tool's utility to that of traditional implements, a study was conducted on a population of 27 potato plants belonging to 9 separate genotypes. Both newly developed and traditional measurement techniques were used to collect measurements of a variety of the plants' characteristics. A multiple linear regression of the plant characteristics on the plants' genetic data showed that the measurements collected by hand were generally better correlated with genetic characteristics than those collected using the developed tool; the average adjusted coefficient of determination for hand-measurements was 0.77, while that of the tool-measurements was 0.66. Though the aggregation of this platform's results is unsatisfactory, this work has demonstrated that such an alternative to traditional data-collection tools is certainly attainable. / Master of Science
27

Visualization of Surfaces and 3D Vector Fields

Li, Wentong 08 1900 (has links)
Visualization of trivariate functions and vector fields with three components in scientific computation is still a hard problem in compute graphic area. People build their own visualization packages for their special purposes. And there exist some general-purpose packages (MatLab, Vis5D), but they all require extensive user experience on setting all the parameters in order to generate images. We present a simple package to produce simplified but productive images of 3-D vector fields. We used this method to render the magnetic field and current as solutions of the Ginzburg-Landau equations on a 3-D domain.
28

Sustainable agriculture: a case study of contour hedgerows in Zigui County, Hubei Province, China.

January 2004 (has links)
Tang Chi Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 104-121) and index. / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.v / Table of Contents --- p.vii / List of Tables --- p.x / List of Figures --- p.xi / List of Plates --- p.xii / Chapter Chapter One --- Introduction / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Conceptual Framework --- p.3 / Chapter 1.3 --- Objectives and Significance --- p.5 / Chapter 1.4 --- Structure of the Thesis --- p.7 / Chapter Chapter Two --- Literature Review / Chapter 2.1 --- Impacts of Soil Erosion on Agriculture --- p.8 / Chapter 2.2 --- Farmland Shortage Problems in the Reservoir Region --- p.10 / Chapter 2.3 --- Terracing Systems in China --- p.11 / Chapter 2.4 --- Contour Hedgerows --- p.13 / Chapter 2.5 --- Sustainable Agriculture and its Development in China --- p.18 / Chapter Chapter Three --- Study Area / Chapter 3.1 --- The Three Gorges Reservoir Region --- p.22 / Chapter 3.2 --- Geographical Settings of Zigui County --- p.23 / Chapter 3.2.1 --- Geographical and Administrative Location --- p.23 / Chapter 3.2.2 --- Geology and Geomorphology --- p.24 / Chapter 3.2.3 --- Soils --- p.25 / Chapter 3.2.4 --- Climate --- p.25 / Chapter 3.2.5 --- Hydrology --- p.26 / Chapter 3.3 --- Socioeconomic Conditions of Zigui County --- p.26 / Chapter 3.3.1 --- Demography --- p.26 / Chapter 3.3.2 --- Educational Attainments --- p.27 / Chapter 3.3.3 --- Economic and Social Development --- p.27 / Chapter 3.4 --- Environmental Problems in Zigui and the Reservoir Region --- p.28 / Chapter Chapter Four --- Cost-benefit Analysis of Contour Hedgerows / Chapter 4.1 --- Introduction --- p.30 / Chapter 4.2 --- Methodology --- p.32 / Chapter 4.2.1 --- Trial Plot Design --- p.32 / Chapter 4.2.2 --- Cost-benefit Analysis --- p.35 / Chapter 4.2.3 --- Identification and Valuation of Costs --- p.35 / Chapter 4.2.4 --- Identification and Valuation of Benefits --- p.37 / Chapter 4.2.5 --- Discount Rate --- p.37 / Chapter 4.2.6 --- Time Horizon --- p.37 / Chapter 4.2.7 --- Cost-benefit Criterion --- p.38 / Chapter 4.3 --- Results and Discussion --- p.38 / Chapter 4.3.1 --- Investment Costs and Operating Costs --- p.38 / Chapter 4.3.2 --- Replacement Costs --- p.39 / Chapter 4.3.3 --- Benefits --- p.42 / Chapter 4.3.4 --- Net Present Values (NPVs) --- p.44 / Chapter 4.3.5 --- Sensitivity Analysis --- p.47 / Chapter 4.4 --- Conclusion --- p.48 / Chapter Chapter Five --- A Questionnaire Survey of the Comparative Performance of Various Farming Systems / Chapter 5.1 --- Introduction --- p.50 / Chapter 5.2 --- Methodology --- p.52 / Chapter 5.2.1. --- Sampling Method --- p.52 / Chapter 5.2.2. --- Questionnaire --- p.52 / Chapter 5.2.3. --- Analytical Technique --- p.53 / Chapter 5.3 --- Results and Discussion --- p.54 / Chapter 5.3.1. --- Background of Households and Farming Systems --- p.54 / Chapter 5.3.2. --- Net Returns --- p.57 / Chapter 5.3.3. --- Inputs of Inorganic Fertilizers and Organic Manure --- p.61 / Chapter 5.3.4. --- Labour Inputs --- p.64 / Chapter 5.3.5. --- Characteristics of Hedgerow Management --- p.65 / Chapter 5.4 --- Conclusion --- p.66 / Chapter Chapter Six --- An Interview Study of the Perception of Contour Hedgerows / Chapter 6.1 --- Introduction --- p.68 / Chapter 6.2 --- Methodology --- p.70 / Chapter 6.3 --- Results and Discussion --- p.72 / Chapter 6.3.1 --- Familiarity with Hedgerows --- p.72 / Chapter 6.3.2 --- Hedgerow Acceptance in Usage --- p.74 / Chapter 6.3.3 --- Factors of Hedgerow Implementation --- p.79 / Chapter 6.3.4 --- Variation of Agricultural Inputs and Outputs --- p.83 / Chapter 6.3.5 --- Values of Indigenous Knowledge --- p.86 / Chapter 6.3.6 --- Implications for Hedgerow Extension --- p.88 / Chapter 6.4 --- Conclusion --- p.90 / Chapter Chapter Seven --- Conclusion / Chapter 7.1 --- Summary of Findings --- p.92 / Chapter 7.2 --- Synthesis of the Study --- p.95 / Chapter 7.3 --- Limitations of the Study --- p.100 / Chapter 7.4 --- Suggestions for Further Studies --- p.101 / Bibliography --- p.104 / Appendix I: Structured Questionnaire --- p.122 / Appendix II: Interview Guide for Hedgerow Users --- p.131 / Appendix III: Interview Guide for Non-hedgerow Users --- p.134 / Appendix IV: Interview Guide for Government Officials --- p.137 / Appendix V: Index --- p.140 / "Appendix VI: Publication-Cost-benefit Analysis of Contour Hedgerow in the Three Gorges Region (Published in ´ب´بResources Science´ح,Vol26 Supplement,pp. 132-136)" --- p.145
29

CDAR : contour detection aggregation and routing in sensor networks

Pulimi, Venkat 05 May 2010
Wireless sensor networks offer the advantages of low cost, flexible measurement of phenomenon in a wide variety of applications, and easy deployment. Since sensor nodes are typically battery powered, energy efficiency is an important objective in designing sensor network algorithms. These algorithms are often application-specific, owing to the need to carefully optimize energy usage, and since deployments usually support a single or very few applications.<p> This thesis concerns applications in which the sensors monitor a continuous scalar field, such as temperature, and addresses the problem of determining the location of a contour line in this scalar field, in response to a query, and communicating this information to a designated sink node. An energy-efficient solution to this problem is proposed and evaluated. This solution includes new contour detection and query propagation algorithms, in-network-processing algorithms, and routing algorithms. Only a small fraction of network nodes may be adjacent to the desired contour line, and the contour detection and query propagation algorithms attempt to minimize processing and communication by the other network nodes. The in-network processing algorithms reduce communication volume through suppression, compression and aggregation techniques. Finally, the routing algorithms attempt to route the contour information to the sink as efficiently as possible, while meshing with the other algorithms. Simulation results show that the proposed algorithms yield significant improvements in data and message volumes compared to baseline models, while maintaining the integrity of the contour representation.
30

CDAR : contour detection aggregation and routing in sensor networks

Pulimi, Venkat 05 May 2010 (has links)
Wireless sensor networks offer the advantages of low cost, flexible measurement of phenomenon in a wide variety of applications, and easy deployment. Since sensor nodes are typically battery powered, energy efficiency is an important objective in designing sensor network algorithms. These algorithms are often application-specific, owing to the need to carefully optimize energy usage, and since deployments usually support a single or very few applications.<p> This thesis concerns applications in which the sensors monitor a continuous scalar field, such as temperature, and addresses the problem of determining the location of a contour line in this scalar field, in response to a query, and communicating this information to a designated sink node. An energy-efficient solution to this problem is proposed and evaluated. This solution includes new contour detection and query propagation algorithms, in-network-processing algorithms, and routing algorithms. Only a small fraction of network nodes may be adjacent to the desired contour line, and the contour detection and query propagation algorithms attempt to minimize processing and communication by the other network nodes. The in-network processing algorithms reduce communication volume through suppression, compression and aggregation techniques. Finally, the routing algorithms attempt to route the contour information to the sink as efficiently as possible, while meshing with the other algorithms. Simulation results show that the proposed algorithms yield significant improvements in data and message volumes compared to baseline models, while maintaining the integrity of the contour representation.

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