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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.
121

Guidelines for the Partial Area under the Summary Receiver Operating Characteristic (SROC) Curve

Fill, Roxanne 12 1900 (has links)
<p> The accuracy of a diagnostic test is often evaluated with the measures of sensitivity and specificity and the joint dependence between these two measures is captured by the receiver operating characteristic (ROC) curve. To combine multiple testing results from studies that are assumed to follow the same underlying probability law, a smooth summary receiver operating characteristic (SROC) curve can be fitted. Moses et al. (1993) proposed a least squares approach to fit the smooth SROC curve. </p> <p> In this thesis we overview the summary measures for the ROC curve in single study data as well as the summary statistics for the SROC curves in meta-analysis. These summary statistics include, the area under the curve (AUC), Q* statistic, area swept under the curve (ASC) and the partial area under the curve (pAUC). </p> <p> Our focus, however is mainly on the partial area under the SROC curve as it is being used frequently in meta-analysis of diagnostic testing. The appeal to use the pAUC instead of the full AUC is that the partial area can be used to focus on a clinically relevant region of the SROC curve where false positive rate (FPR) is small. Simulations and considerations for the use of the summary indices of the ROC and SROC curves are presented here. </p> / Thesis / Master of Science (MSc)
122

Recurrence Properties of Measure-Preserving Actions of Abelian Groups and Applications

Ackelsberg, Ethan 01 September 2022 (has links)
No description available.
123

Transport and Anisotropy inside Ionic Polymer Membranes

Hou, Jianbo 26 October 2012 (has links)
Water and ion transport critically determine the performance of many functional materials and devices, from fuel cells to lithium ion batteries to soft mechanical actuators. This dissertation aims to address some fundamental issues regarding transport and anisotropy, structural heterogeneity and molecular interactions inside ionic polymers. I first discuss a main deficiency of a standard protocol for calibrating high pulsed-field-gradient NMR. I show that high gradient calibration using low γ nuclei is not amenable to measurements on slow diffusing high γ nuclei. Then I employ NMR diffusometry to investigate transport and anisotropy for a series of ionic polymers, from poly(arylene ether sulfone) hydrophilic-hydrophobic multi-block copolymers to polymer blends to perfluorosulfonate random copolymers. For the multi-block copolymers, NMR diffusion measurements yield diffusion anisotropy as a function of water uptake and block lengths. ²H NMR spectroscopy on absorbed D₂O probes membrane alignment modes. These measurements also provide insights into average defect distributions. For the blend membranes, we examine the impact of compatibilizer on their transport properties. An increase in compatibilizer significantly improves the membrane phase homogeneity confirmed by SEM and transport studies. Theories of diffusion in porous media yield changes in domain size and tortuosity that correspond to drastic changes in local restrictions to water diffusion among different blend membranes. NMR relaxometry studies yield multi-component T₁ values, which further probe structural heterogeneities on smaller scales than diffusion experiments. For the random copolymer, the exploration of ion transport reveals inter-ionic associations of ionic liquids (ILs) modulated by hydration level and ionic medium. When ILs diffuse inside ionic polymers, isolated anions diffuse faster (≥ 4X) than cations at high hydration whereas ion associations result in substantially faster cation diffusion (≤ 3X) at low hydration inside membranes, revealing prevalent anionic aggregates. Finally, I present the strategy and analytical protocol for studying ionomer membranes using ILs. The normal cation diffusion contrasts to the anomalous anion diffusion caused by local confinement structures inside the membranes, which vary drastically with temperature and hydration level. These structures correspond to a density variation of SO₃⁻ groups, which define a distribution of local electrical potentials that fluctuate with temperature and nature of ionic media. / Ph. D.
124

Comparison of Paul and Morlet Wavelets for Measuring the Characteristic Scale of Peak Pressure Events on Low-Rise Structures

Chabalko, Christopher Carter 23 August 2001 (has links)
A methodology to measure a characteristic time scale (duration) of peaks in pressure and velocity data is presented. This methodology is based on the use of the Morlet and Paul wavelets. Detailed descriptions of these wavelets and their implementation procedures are given. The results show that similar time scales or durations can be measured using either Morlet or Paul wavelets. To obtain consistent results data windowing might need to be applied. Using the Paul wavelet, durations of events measured in different wind tunnel simulations are obtained and discussed. / Master of Science
125

The Multidimensional Interpersonal Dependency Inventory: Scale Development

Shlien, Rania K. 22 January 2001 (has links)
Current inventories of interpersonal trait dependency are problematic because they are based on theories that fail to recognize the positive aspects of dependency. The main goal of this thesis was to develop a new inventory that takes into account theoretical advances using Robert Bornstein's definitions and identified components of interpersonal dependency. The study was broken into the following three stages: 1. Item and inventory creation, 2. Expert feedback and interrater reliability and 3. Data collection and analysis. Three-hundred fifteen undergraduates completed a questionnaire packet, consisting of a demographics section, a copy of the new inventory, and seven other inventories that measure dysfunction and well-being. Although the original hypotheses in this work were not supported, exploratory factor analysis yielded four factors. These four factors and their relevance to the measurement of interpersonal dependency are discussed and suggestions are made for future studies. / Master of Science
126

Performance Evaluation of Equal Gain Diversity Systems In Fading Channels

Viswanathan, Ramanathan 12 January 2004 (has links)
Next generation wireless systems are being designed to provide ubiquitous broadband link access to information infrastructure. Diversity techniques play a vital role in supporting such high speed connections over radio channels by mitigating the detrimental effects of multiuser interference and multipath fading. Equal gain combining (EGC) diversity receiver is of practical interest because of its reduced complexity relative to optimum maximal ratio combining scheme while achieving near-optimal performance. Despite this, the literature on EGC receiver performance is meager owing to difficulty in deriving the probability density function of the diversity combiner output. This problem is further compounded when the diversity paths are correlated. Since spatial, pattern, or polarization diversity implementations at a mobile handset are usually limited to a small diversity order with closely spaced antenna elements (owing to cost and ergonomic constraints), any performance analysis must be revamped to account for the effects of branch correlation between the combined signals. This thesis presents a powerful characteristic function method for evaluating the performance of a two-branch EGC receiver in Nakagami-m channels with non-independent and non-identical fading statistics. The proposed framework facilitates efficient error probability analysis for a broad range of modulation/detection schemes in a unified manner. The thesis also examines the efficacy of an average diversity combiner in slotted direct sequence spread-spectrum access packet radio networks. A two-dimensional EGC diversity combining scheme is introduced, wherein a corrupted packet is retained and combined with its retransmission at the bit level to produce a more reliable packet. The mathematical analysis of the average diversity combiner presented in this thesis is sufficiently general to handle generalized fading channel models with independent fading statistics for a myriad of digital modulation schemes. / Master of Science
127

Regularized equivariant Euler classes and gamma functions.

Lu, Rongmin January 2008 (has links)
We consider the regularization of some equivariant Euler classes of certain infinite-dimensional vector bundles over a finite-dimensional manifold M using the framework of zeta-regularized products [35, 53, 59]. An example of such a regularization is the Atiyah–Witten regularization of the T-equivariant Euler class of the normal bundle v(TM) of M in the free loop space LM [2]. In this thesis, we propose a new regularization procedure — W-regularization — which can be shown to reduce to the Atiyah–Witten regularization when applied to the case of v(TM). This new regularization yields a new multiplicative genus (in the sense of Hirzebruch [26]) — the ^Γ-genus — when applied to the more general case of a complex spin vector bundle of complex rank ≥ 2 over M, as opposed to the case of the complexification of TM for the Atiyah–Witten regularization. Some of its properties are investigated and some tantalizing connections to other areas of mathematics are also discussed. We also consider the application of W-regularization to the regularization of T²- equivariant Euler classes associated to the case of the double free loop space LLM. We find that the theory of zeta-regularized products, as set out by Jorgenson–Lang [35], Quine et al [53] and Voros [59], amongst others, provides a good framework for comparing the regularizations that have been considered so far. In particular, it reveals relations between some of the genera that appeared in elliptic cohomology, allowing us to clarify and prove an assertion of Liu [44] on the ˆΘ-genus, as well as to recover the Witten genus. The ^Γ₂-genus, a new genus generated by a function based on Barnes’ double gamma function [5, 6], is also derived in a similar way to the ^Γ-genus. / Thesis (Ph.D.) - University of Adelaide, School of Mathematical Sciences, 2008
128

Regularized equivariant Euler classes and gamma functions.

Lu, Rongmin January 2008 (has links)
We consider the regularization of some equivariant Euler classes of certain infinite-dimensional vector bundles over a finite-dimensional manifold M using the framework of zeta-regularized products [35, 53, 59]. An example of such a regularization is the Atiyah–Witten regularization of the T-equivariant Euler class of the normal bundle v(TM) of M in the free loop space LM [2]. In this thesis, we propose a new regularization procedure — W-regularization — which can be shown to reduce to the Atiyah–Witten regularization when applied to the case of v(TM). This new regularization yields a new multiplicative genus (in the sense of Hirzebruch [26]) — the ^Γ-genus — when applied to the more general case of a complex spin vector bundle of complex rank ≥ 2 over M, as opposed to the case of the complexification of TM for the Atiyah–Witten regularization. Some of its properties are investigated and some tantalizing connections to other areas of mathematics are also discussed. We also consider the application of W-regularization to the regularization of T²- equivariant Euler classes associated to the case of the double free loop space LLM. We find that the theory of zeta-regularized products, as set out by Jorgenson–Lang [35], Quine et al [53] and Voros [59], amongst others, provides a good framework for comparing the regularizations that have been considered so far. In particular, it reveals relations between some of the genera that appeared in elliptic cohomology, allowing us to clarify and prove an assertion of Liu [44] on the ˆΘ-genus, as well as to recover the Witten genus. The ^Γ₂-genus, a new genus generated by a function based on Barnes’ double gamma function [5, 6], is also derived in a similar way to the ^Γ-genus. / Thesis (Ph.D.) - University of Adelaide, School of Mathematical Sciences, 2008
129

Study of the strategic decision making process in higher education institutions

Aldhaen, Esra Saleh January 2017 (has links)
The strategic decision making process (SDMP) is a major issue in organisations. It is part of the larger topic of strategic management and related to strategic planning. Achievement of strategic objectives outlined in the strategic plan of an organisation depends on the decisions taken through the process. Yet the literature shows that the concept of SDMP is not well understood and organisations find it difficult to develop and implement an SDMP, particularly Higher Education Institutions (HEIs). The literature indicates that decisions are taken in organizations in different ways for example using intuition, data, collaboration and ad-hoc considerations. In addition contextual factors are argued to affect the SDMP although very little research has been conducted to explain how contextual factors affect SDMP they do in HEIs. Some examples of contextual factors namely decision process characteristics have been identified and discussed as part of the SDMP literature in industry. However, lack of knowledge about SDMP and how contextual factors influence SDMP is regarded as to be a major obstacle for HEIs in taking decisions and choosing the best alternative amongst available decisions. This research seeks to contribute to address this important issue. Whilst there are many strategic decision characteristics (contextual factors) identified in the literature, this research focuses on decision importance. The rationale for choosing decision importance was that there is always some concern in the minds of the decision makers in the HEIs on what constitutes an important decision. What is considered as important decision while the decision is being taken may prove to be less important after implementation if there is no clear understanding of how to assign importance to a decision. Even in the industrial sector, Elbanna and Child (2007) it has been argued that decision importance has not been studied well. Relying upon the theoretical model developed by Elbanna and Child and other arguments found in the literatue, this research argued that the SDMP is a combination of relationships between decision characteristics, SDMP characteristics and decision outcomes that are influenced by environmental factors. As far as environmental factors were concerned environmental uncertainty was chosen as an external environment factor while organisational performance was chosen as the internal contextual factor. These two factors were argued to moderate the relationship between SDMP characteristics and SDMP outcomes and theoretical support for this conceptualisation was taken from the model developed by Elbanna and Child. A research model was developed to address the research questions, and the aim of the study was “to examine the different decision specific characteristic, SDMP characteristic and SDMP process outcome variables and develop a relationship amongst them in the context of HEIs in a changing environment”. The research was conducted in the United States of America and data was gathered from faculty members involved in decision making at the department level and higher. A positivist epistemological and objective ontological stance was adopted and a deductive approach was used. The research model was tested using the data collected from 485 valid responses to a survey questionnaire. Linear regression was the primary analysis approach and supplemented by path analysis. Results from the regression analysis showed that decision importance exerts influence on decision effectiveness through the mediators, rationality in decision making, intuition and decentralization in decision making. However, the outcome of path analysis showed that only rationality in decision making and intuition are important while decentalisation was not found to be statistically significant. Similarly environmental factors exerted pressure only on the relationship between rationality in decision making and decision effectiveness. The contradicting SDMP factors rationality in decision making and intuition were both found to be necessary to SDMP in the HEI context. This research has contributed to knowledge in terms of establishing a relationship between decision importance and decision process effectiveness mediated by rationality in decision making and intuition and development of the model. Theoretically the findings of this research show that the modification imposed on the model developed by Elbanna and Child was found to be statistically significant and found support from the literature. Environmental factors affected the relationship between rationality in decision making and decision effectiveness. This research has provided a model that can be used to help decision makers in HEIs to implement SDMP practically in the organization, to guide the process towards more robust decisions. The findings of this research find application in supporting policy makers to increase the likelihood of more effective decisions so that the decisions taken more effective.
130

Biometria, bionomia e ecologia de aves em áreas de cerradão na Floresta Nacional do Araripe - FLONA Araripe, Ceará, Brasil

FERREIRA, Jullio Marques Rocha 29 July 2013 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-12T12:09:56Z No. of bitstreams: 1 Jullio Marques Rocha Ferreira.pdf: 2391447 bytes, checksum: 2c34ed3e38972182ada8046ba66c80ae (MD5) / Made available in DSpace on 2016-08-12T12:09:56Z (GMT). No. of bitstreams: 1 Jullio Marques Rocha Ferreira.pdf: 2391447 bytes, checksum: 2c34ed3e38972182ada8046ba66c80ae (MD5) Previous issue date: 2013-07-29 / This study evaluates biological and ecological characteristics of the avian fauna present in areas of the National Forested Savanna (Cerradão) of Araripe, Ceará (FLONA). The major objectives are: describe the avian fauna composition and frequency of occurrence of species, classify species as to their ecological attributes, investigate both bionomics and biometrics data and finally, test the following hypotheses: (i) a relationship exists between the change of seasons (dry and rainy season) and observations of changes in breast plate plumage of the species caught and (ii) phenotypic variations exist in those species captured that have sexual dimorphism.. Data collection occurred through mist net capture of individuals, direct visual and auditory observations as well as use of the Mackinnon method. Between December 2011 and November 2012 116 species (48 families) were recorded and 583 individuals belonging to 59 species of 24 families were captured, with a sampling effort of 91,140 m2.h. In addition to recovery of leg bands fitted in the current research a leg band from a previous study was also retrieved (Neopelma pallences with a leg band duration of 18 years). The species with the highest frequency of occurrence were Thamnophilus pelzelni (57.4%), Turdus leucomelas (53.6%), Tangara cayana and Euphonia chlorotica combined (41.3%). The vertical stratification of vegetation occupied by the avian fauna was medium to high and the social status most observed was of solitary individuals. Regarding eating habits, there was a predominance of insectivorous birds followed by fruitarian birds. A significant number of birds which are indicators of good environmental quality, as well as species sensitive to disturbance, were visualized. The relationship between seasonality and pattern of changes in breast plate plumage in species caught was evident. There was no significant weight difference in species with sexual dimorphism to biometric data, only a case of the wing length of Tangara cayana which was significant. The results infer that the FLONA is in a good state of conservation and containing a high diversity of avian fauna. Studies such as this, in addition to implementing literature with biometrics and bionomic data about species, corroborate the formation of management plans in areas of forested savanna, presently severely degraded due to anthropic actions. / O estudo avaliou características biológicas e ecológicas da avifauna presente em áreas de Cerradão na Floresta Nacional do Araripe, Ceará e teve como objetivos: descrever a composição avifaunística e a frequência de ocorrência das espécies, classificar as espécies quanto aos seus atributos ecológicos, averiguar dados da bionomia e biometria, bem como testar as seguintes hipóteses: (i) existe relação entre a mudança das estações (período seco e chuvoso) e a constatação de muda e placa de choco das espécies capturadas e (ii) há diferenças fenotípicas nas espécies capturadas com dimorfismo sexual. A coleta de dados se deu através da captura de indivíduos por rede de neblina, observações visuais e auditivas diretas, além da utilização do método de Mackinnon. Entre dezembro de 2011 e novembro de 2012, foram registradas 116 espécies (48 famílias) e capturadas 583 indivíduos distribuídos em 59 espécies de 24 famílias, com um esforço amostral de 91.140 m2.h. Além das recuperações de anilhas providas da atual pesquisa, também foi recuperada uma anilha de um estudo anterior (Neopelma pallences, com tempo de anilha de 18 anos). As espécies que apresentaram maior frequência de ocorrência foram Thamnophilus pelzelni (57,4%), Turdus leucomelas (53,6%), Tangara cayana e Euphonia chlorotica, ambas com (41,3%). A estratificação vertical da vegetação mais ocupada pela avifauna foi à mediana/alta e o padrão social mais visualizado foi o solitário. Em relação ao hábito alimentar, observou-se predominância de aves insetívoras, seguida de frugívoras. Um número expressivo de aves indicadoras de boa qualidade ambiental e de espécies sensíveis a distúrbios foram visualizados. Pôde-se observar relação entre a sazonalidade e o padrão de muda e de placa de choco nas espécies capturadas. Não houve diferença significativa de peso nas espécies com dimorfismos sexual e quanto aos dados biométricos, apenas o comprimento da asa do Tangara cayana foi significativo. Os resultados inferem que a FLONA apresenta um bom estado de conservação ambiental, com uma alta riqueza avifaunisca. Estudos como este, além de implementarem a literatura com dados biométricos e bionômicos das espécies, corroboram para formação de planos de manejos em áreas de Cerradão, atualmente bastante degradado devido ações antrópicas.

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