• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2213
  • 1950
  • 442
  • 287
  • 180
  • 149
  • 50
  • 35
  • 34
  • 33
  • 26
  • 26
  • 24
  • 23
  • 22
  • Tagged with
  • 6404
  • 3071
  • 1628
  • 1613
  • 1122
  • 830
  • 568
  • 550
  • 521
  • 509
  • 498
  • 458
  • 426
  • 402
  • 398
  • 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.
401

Image Information Distance Analysis and Applications

Nikvand, Nima January 2014 (has links)
Image similarity or distortion assessment is fundamental to a broad range of applications throughout the field of image processing and machine vision. These include image restoration, denoising, coding, communication, interpolation, registration, fusion, classification and retrieval, as well as object detection, recognition, and tracking. Many existing image similarity measures have been proposed to work with specific types of image distortions (e.g., JPEG compression). There are also methods such as the structural similarity (SSIM) index that are applicable to a wider range of applications. However, even these "general-purpose" methods offer limited scopes in their applications. For example, SSIM does not apply or work properly when significant geometric changes exist between the two images being compared. The theory of Kolmogorov complexity provides solid groundwork for a generic information distance metric between any objects that minorizes all metrics in the class. The Normalized Information Distance (NID) metric provides a more useful framework. While appealing, the challenge lies in the implementation, mainly due to the non-computable nature of Kolmogorov complexity. To overcome this, a Normalized Compression Distance (NCD) measure was proposed, which is an effective approximation of NID and has found successful applications in the fields of bioinformatics, pattern recognition, and natural language processing. Nevertheless, the application of NID for image similarity and distortion analysis is still in its early stage. Several authors have applied the NID framework and the NCD algorithm to image clustering, image distinguishability, content-based image retrieval and video classification problems, but most reporting only moderate success. Moreover, due to their focuses on ! specific applications, the generic property of NID was not fully exploited. In this work, we aim for developing practical solutions for image distortion analysis based on the information distance framework. In particular, we propose two practical approaches to approximate NID for image similarity and distortion analysis. In the first approach, the shortest program that converts one image to another is found from a list of available transformations and a generic image similarity measure is built on computing the length of this shortest program as an approximation of the conditional Kolmogorov complexity in NID. In the second method, the complexity of the objects is approximated using Shannon entropy. Specifically we transform the reference and distorted images into wavelet domain and assume local independence among image subbands. Inspired by the Visual Information Fidelity (VIF) approach, the Gaussian Scale Mixture (GSM) model is adopted for Natural Scene Statistics (NSS) of the images to simplify the entropy computation. When applying image information distance framework in real-world applications, we find information distance measures often lead to useful features in many image processing applications. In particular, we develop a photo retouching distortion measure based on training a Gaussian kernel Support Vector Regression (SVR) model using information theoretic features extracted from a database of original and edited images. It is shown that the proposed measure is well correlated with subjective ranking of the images. Moreover, we propose a tone mapping operator parameter selection scheme for High Dynamic Range (HDR) images. The scheme attempts to find tone mapping parameters that minimize the NID of the HDR image and the resulting Low Dynamic Range (LDR) image, and thereby minimize the information loss in HDR to LDR tone mapping. The resulting images created by minimizing NID exhibit enhanced image quality.
402

Hur biodiversitet på ekosystemnivå skiljer sig mellan olika habitat / How biodiversity at the ecosystem level differs between different habitats

Grafström, Amanda January 2014 (has links)
Biodiversity can be described as the total variation of life forms, where diversity ranges from gene level up to the ecosystem level. The diversity can be calculated in a number of ways, and this study use one of these methods. In this study empirical food webs have been used and analyzed, where eleven characters are defined and used as parameters to calculate the Euclidean distances between food webs that describe the variation that may exist within classes of terrestrial, marine and freshwater habitats. The class who stood out and showed the greatest diversity at the ecosystem level was the marine food webs, which showed a high value of the average euclidean distance. The other networks were not as distinctive and the average of the euclidean distance in these classes was comparatively low.
403

Essays in domestic transport costs and export regions in South Africa / Marianne Matthee

Matthee, Marianne January 2007 (has links)
This thesis investigates the impact of domestic transport costs and location on exports originating from exporting regions within a developing country. It is presented in the form of three articles, each addressing a different aspect. These articles are accompanied by a literature review of the background and impact of domestic transport costs on trade. The first article provides empirical evidence for the significance of domestic transport costs in exports and the spatial location of manufacturing exporters. Cubic-spline density functions are used and the results indicate (a) the proximity to a port is an important consideration in most export-oriented manufacturing firms' location, with more than 70% of manufactured exports in South Africa originating from a band of 100 km from an export hub; and (b) there appears to be a second band of these firms at a distance of between 200 and 400 km from the hub. Between 1996 and 2004, manufactured exports in the band between 200 km and 400 km from the nearest hub increased, suggesting either an increase in manufactured exports that depend on natural resources due to demand factors, and/or a decrease in domestic transport costs, amongst others. The second article investigates the question of the location of exporters of manufactured goods within a country. Based on insights from new trade theory, the new economic geography (NEG) and gravity-equation modelling, an empirical model is specified with agglomeration and increasing returns (the home-market effect) and transport costs (proxied by distance) as major determinants of the location decision of exporters. Data from 354 magisterial districts in South Africa are used with a variety of estimators (OLS, Tobit, RE-Tobit) and allowances for data shortcomings (bootstrapped standard errors and analytical weights) to identify the determinants of regional manufactured exports. It is found that the home-market effect (measured by the size of local GDP) and distance (measured as the distance in km to the nearest port) are significant determinants of regional manufactured exports. This article contributes to the literature by using developing country data, and by adding to the small literature on this topic. This article complements the work of Nicolini (2003) on the determinants of exports from European regions and finds that the home-market effect is relatively more important in the developing country context (South Africa), a finding consistent with theoretical NEG models such as those of Puga (1998). The third article is an empirical study of the relationship between export diversity and economic growth in a developing country context. Using export data from19 sectors within 354 sub-national (magisterial) districts of South -Africa, various measures of subnational export diversity are constructed. It is found that it is not only important how much is exported, but that it is also important what it is that is exported. Regions with less specialisation and more diversified exports generally experienced higher economic growth rates, and contributed more to overall exports from South Africa. It is also found that distance (and thus domestic transport costs) from a port is inversely related to the degree of export diversity. Estimating a cubic-spline density function for the Herfindahl index measure of export diversity, it is found that export diversity declines as the distance from a port (export hub) increases. Most magisterial districts with high export diversity values are located within 100 km of the nearest port. Furthermore, comparing the cubic-spline density functions for 1004 with those of 1996 shows that distance (domestic transport costs) has become more important since 1996 (under greater openness) with magisterial districts located further than 100 km from the ports being less diverse in 2003 than in 1996. One may speculate that a possible explanation for this changing pattern of export diversity may be the impact of greater foreign direct investment (FDI) in South Africa since 1996. / Thesis (Ph.D. (International Commerce))--North-West University, Potchefstroom Campus, 2007
404

Adult Attachment Orientation and Physical Distance: Do Threat Primes Alter Perceptions of Interpersonal Proximity?

REFLING, ERICA 21 April 2014 (has links)
The purpose of my dissertation was to examine whether adult romantic attachment and interpersonal threat bias people’s perceptions of physical distance within a social context. Across three separate studies, I assessed the interactive effects of attachment anxiety, attachment avoidance, and threat on perceptions of distance. In the baseline (control) condition, I predicted that people higher in attachment anxiety would perceive greater interpersonal closeness than people lower in attachment anxiety. However, in the threat condition, I predicted that this perceptual difference would disappear or, alternatively, that people higher in attachment anxiety would perceive greater interpersonal distance than people lower in attachment anxiety. Furthermore, I hypothesized that higher levels of attachment avoidance would be associated with greater perceptions of physical distance regardless of condition. In Study One, I used a loneliness prime and measured attachment orientation to examine their influence on the strength of the tendency to perceive an ambiguous, computerized figure as walking toward oneself. In Study Two, I investigated how attachment and the threat of separation affected estimations of physical distance from one’s romantic partner who was standing relatively close by. In the third and final study, I examined the impact of attachment and separation threat on perceptions of physical distance from one’s romantic partner when the partner was absent and imagined to be in another city. A meta-analysis of the experiments revealed that the influence of attachment anxiety on distance perception was not only dependent on condition, but also on attachment avoidance. Specifically, for people high in attachment avoidance in the control condition, higher attachment anxiety was associated with smaller perceptions of distance. In contrast, for people high in attachment avoidance in the threat condition, higher attachment anxiety was associated with greater perceptions of distance. For people low in attachment avoidance in both conditions, attachment anxiety did not predict distance perception. This pattern is partially consistent with, but also more complicated than, my original predictions. Explanations for the findings are discussed as well as future directions for investigation. Additionally, the important implications of this research for real-life interactions and, ultimately, the development and maintenance of attachment orientation are explored. / Thesis (Ph.D, Psychology) -- Queen's University, 2014-04-21 12:36:58.104
405

It's About Time: Applying a Daily Diary Design to Investigate the Dynamic Relationships between Temporal Perspective and Well-Being

Rush, Jonathan 30 September 2013 (has links)
Temporal perspective is a multi-dimensional term for how individuals focus attention toward the past, present, and future. There have been few investigations into the relationship between temporal perspective and well-being. Temporal perspective has predominantly been measured with single-occasion measurement designs, which ignore the potential for within-person variations that may be important in accounting for fluctuations in well-being. The current study examined the dimensions of temporal perspective (temporal focus, temporal attitude, and temporal distance) and their dynamic relationships with well-being. A 14-day daily diary design was employed to examine whether people fluctuate in their temporal perspective, and if these fluctuations systematically covary with daily well-being. The results from multilevel analyses supported the following conclusions: (a) there is evidence of within-person variability in daily temporal perspective, and (b) this within-person variability in temporal perspective fluctuates systematically with fluctuations in daily well-being. Each temporal perspective dimension was useful in predicting daily well-being. / Graduate / 0621
406

A COMPARISON OF VISUALISATION TECHNIQUES FOR A BICYCLE SIMULATOR

Cosimato, Pasquale January 2014 (has links)
In this project, the perception of distance and the degree of immersion in a game, with two different visualisation techniques, have been evaluated. A bicycle simulator was used, and the game has been tested in a non-immersive virtual reality, by projecting the game on a screen, and using an immersive virtual reality by Oculus Rift. The study provides a preliminary investigation that focuses on how humans can perceive the distance, an overview of the term immersion and how to quantify this component.Regarding the study of the perception of distance, to subjects who have tested the game has been asked their perceptions of distance with respect to a given object. The immersion was studied and evaluated using a questionnaire given to each subject.The results showed an underestimation of distance in both the visualisation of the game, precisely a greater underestimation respect to real distance when the screen was used was found.The degree of immersion did not detect large differences between the two visualisation techniques.
407

A veritable psychology : Walter Pater's art criticism

Carpenter, Kenneth Erwin January 2000 (has links)
No description available.
408

Cross-cultural adjustment of inpatriates : Indian inpatriates in Sandvik

Habteab, Biniam Gebremichael, ODURO, STEVE ASARE January 2014 (has links)
Purpose The purpose of this study is to investigate the influence of cultural distance in cross-cultural adjustment of inpatriates. Furthermore, it investigates the role  of organizational and social support in cross-cultural adjustment. Method In order to achieve the purpose of this study a qualitative method of data gathering was chosen. A case study was conducted in Sandvik Sweden in Gävle, and personal interviews were done with the Indian inpatriates and other representatives involved in international assignment. Findings The cultural distance between Sweden and Indian  directly affect the concept of teamwork in Sandvik-Sweden and Sanvik-India. To understand the cultural background and  motive of  inpatriates is important  in designing organizational support that facilitates anticipatory and in-country adjustment processes. The existence of a recognized socializing way at headquarter eases to interact and develop interpersonal relationship, which facilitate the adjustment process of inpatriates through  referral made from known sources. Implication and suggestion for the future This study can assist multinational companies that are interested in the Cross- cultural adjustment process of inpatriates. We suggest for additional investigations in different organizational setup about the same subject matter to compare new results with the current findings. Future researchers can also investigate the impact of repatriation of inpatriates’ in cross- cultural adjustment. / Masters Thesis
409

Identification of Push-to-Talk Transmitters Using Wavelets

Payal, Yalçin 12 1900 (has links)
The views expressed in this thesis are those of the author and do not reflect the official policy or position of the Department of Defense or the U.S. Government. / The main objective of this study is to find a wavelet-based, feature extracting algorithm for push-to-talk transmitter identification. A distance-measure algorithm is introduced to classify signals belonging to one of four transmitters. The signals are first preprocessed to put them into a form suitable for wavelet analysis. The preprocessing scheme includes taking the envelopes and differentials. Median filtering is also applied to the outputs of the wavelet transform. The distance algorithm uses local extrema of the wavelet coefficients, and computes the distance between the local extrema of a template and the processed signals. A small distance implies high similarity . A signal from each transmitter is selected as a template. A small distance measure indicates that the signal belongs to the transmitter from which the template originated. The distance algorithm can classify correctly the four different signal sets provided for the research. Even at lower signal-to-noise levels, good identification is achieved.
410

Conceptualisations of educational technology in distance education : with special reference to the British Open University, the Spanish Universidad Nacional de Educacion a Distancia, and the Portuguese Universidade Aberta

Gonzalez Estepa, Francisco Javier January 2002 (has links)
No description available.

Page generated in 0.0422 seconds