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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.
31

Public information resource centre : knowledge transference, connectivity, community

Steyn, Konrad 09 December 2010 (has links)
The project is situated within the underdeveloped periphery of Mamelodi. It addresses urban issues of connectivity at a physical, spatial and educational level, as a setting for the proposed architectural intervention. The thesis explores a number of architectural issues, mainly the design of a multi-functional information and resource centre to facilitate a series of public, civic and economic services. These issues are formed through programmes which concern information and knowledge provision. Aspects that informed the nature and scope of the intervention include methods of knowledge distribution, the role of the public library as one beyond that of its functional origin and the potential of the building type to serve as a catalyst within a community. Owing to the physical and programmatic context of the building, it needs to offer adaptability, flexibility and eventually change; both in terms of changing information technologies and within an informal trading-dominant society. Pertinent considerations are small scale construction methods that would allow the participation of local contractors, the creation of tectonics and articulation of space with which the community can associate as well as energy saving principles to allow minimal cost. / Dissertation (MArch(Prof))--University of Pretoria, 2010. / Architecture / unrestricted
32

Understanding brain functional connectivity using graphical models

January 2021 (has links)
archives@tulane.edu / With the rapid development of precision medicine across almost all areas of medicine, the Research Domain Criteria (RDoC) project has been initiated to develop data-driven matrices toward precision medicine for mental disorder by integrating multilevel information including genomics, molecules, circuits, and behaviors. This thesis, under the guidance of the RDoC framework, aims to gain a more complete understanding of the role of oscillatory behavior and network connectivity in normal/abnormal brain functioning and cognitive development. Two specific topics were involved: 1. Understand the complex mechanism for mental disorder through multiomics data; 2. Study the development of FC from childhood to adulthood using multi-paradigm brain images. We intend to identify new and reliable biomarkers for the purpose of precise diagnosis and can potentially provide an enormous impetus for drug discovery through the comparison of normal and abnormal brains and the investigation of dynamic changes. This thesis proposes several new analytic graphical models (directed and undirected) to assess brain functional connectivity (FC), each targeting a specific problem in the biomedical applications: the psi-learning method to resolve the high dimensionality for networks on voxel level, the latent Gaussian copula model for mix data distributions, the joint Bayesian incorporating estimation to address heterogeneities in undirected graphical models; the psi-LiNGAM and BiLiNGAM for the situations of small sample size and heterogeneities in directed acyclic graphs, respectively. The proposed methods are validated through a series of simulation studies and large genomic and neuroimaging datasets, where they confirm results from previous studies and lead to new biological insights. In addition, we put extra efforts on promoting reproducible research and make the proposed methods widely available to the scientific community by the release of free and open-source codes. / 1 / Aiying Zhang
33

Heritability estimation of reliable connectome features

Xie, Linhui January 2018 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Brain imaging genetics is an emerging research field aimed at studying the underlying genetic architecture of brain structure and function by utilizing different imaging modalities. However, not all the changes in the brain are a direct result of the genetic effect. Furthermore, the imaging phenotypes are promising for genetic analyses are usually unknown. In this thesis, we focus on identifying highly heritable measures of structural brain networks derived from Diffusion Weighted Magnetic Resonance imaging data. Using data for twins that is made available by the Human Connectome Project (HCP), the reliability of edge-level measures, namely fractional anisotropy, fiber length, and fiber number in the structural connectome, as well as seven network-level measures, specifically assortativity coefficient, local efficiency, modularity, transitivity, cluster coefficient, global efficiency, and characteristic path length, were evaluated using intraclass correlation coefficients. In addition, estimates of the heritability of the reliable measures were also obtained. It was observed that across all 64,620 network edges between 360 brain regions in the Glasser parcellation, approximately 5% were significantly high heritability based on fractional anisotropy, fiber length, or fiber number. Moreover, all tested network level measures, that capture network integrity, segregation, or resilience, were found to be highly heritable, having a variance ranging from 59% to 77% that is attributable to an additive genetic effect.
34

Effects Of Isolation On Metapopulation Dynamics In Small-world Networks

Bernard, Alaina Brooke 01 January 2007 (has links)
Simulation models are valuable for making predictions that may be tested in natural systems and for understanding observed patterns. The simulation model developed for this thesis evaluates the effects of spatial network architecture, including organism dispersal patterns and isolation of habitats, on metapopulations. Two fields were merged throughout this project: metapopulation biology and small-world network theory. Small-world networks are characterized in their extremes as scale-free or single-scale. These models potentially simulate the networks of habitats and corridors in which metapopulations operate. Small-world network theory has been used to describe systems as diverse as rivers, the world-wide-web, and protein interactions, but has not been used as an experimental treatment for metapopulation dynamics. I tested the effects of growth rate, dispersal pattern, network architecture (scale-free and single-scale), attack type (targeted or random), and attack severity (0, 5, 10, 20, or 40% attacked populations) on metapopulation size and inter-population variation in a simulated system designed to be relevant to conservation biology and ecology. Metapopulation size and inter-population variation changed due to combinations of dispersal pattern, growth rate, and attack severity. Specifically, metapopulations were most affected by a combination of unidirectional dispersal and low growth rate in both metapopulation number and inter-population variation. However, a significant difference between scale-free and single-scale metapopulations was not found due to a low connectivity in the modeled networks as well as limitations of experimental assumptions. However, future studies that alter the model's assumptions could improve understanding of the influence of landscape structure on at-risk metapopulations.
35

Rekryteringsplattform med fokus på träffsäkerhet

Rönnqvist, Mikaela January 2017 (has links)
Den här uppsatsen undersöker träffsäkerheten på en rekryteringsplattform i form av en webbsida. Digitaliseringens utbredning i samhället har lett till att många rekryterare och arbetsgivare flyttat första delen av sina rekryteringsprocesser till internet. Detta har resulterat i att arbetssökande publicerar sina CV och personliga brev digitalt. Men det finns fortfarande luckor och problem i denna rekryteringskontext, då det finns ett överflöd av olika kanaler att leta på men också att hitta det jobb eller medarbetare som eftersöks. I rapporten undersöks genom intervjuer med målgrupp och interaktiv prototyp hur träffsäkerheten skulle kunna förfinas och förenkla processen för nyexaminerade studenter och arbetsgivare i form av en webbsida. I rapporten kommer jag fram till ett designförslag med en kombination av taggar och en extern sökmotor som bidrar till en ökad träffsäkerhet.
36

Axon morphology in the uncinate fasciculus: a post-mortem analysis of white matter microstructure

Stackpole, Melinda Camryn 06 June 2024 (has links)
The Uncinate Fasciculus (UF) is a white matter association tract responsible for connecting the frontal and temporal lobes of the brain. Its location, general shape, and estimated projections have been visualized and analyzed at low-resolution via diffusion tensor imaging (DTI) in many studies, allowing for a basic understanding of the pathway and its potential functions. Despite this, the microstructural properties of this white matter highway are still relatively unknown as we can estimate characteristics such as myelination and pathway density from low-resolution imaging, but we cannot gain a deeper understanding of the fine characteristics that allow the pathway to function in health and how those features are disrupted in disease. To address this gap, we examined six post-mortem tissue samples, featuring approximately 12,000 axons of the temporal segment of the UF (adjacent to the amygdala and hippocampus) from neurotypical controls. We used high-resolution microscopy to systematically sample and study the microstructure of myelinated axons to characterize the UF for future comparisons to disease states, like Autism Spectrum Disorder (ASD). We provide novel characterization of the microstructure of the UF in both hemispheres, examining density, size, myelination, and trajectories of axons in healthy adult tissue. Our data revealed hemispheric trends of axon characteristics that align with previous imaging studies, including slight left hemispheric asymmetry in regard to density and myelination and a small increase in trajectory variability in the right hemisphere. In addition, like values found previously in the Corpus Callosum, the distribution of thin and medium axons was much higher than thick axons. Our findings provide a more in-depth understanding of the microstructural characteristics of the UF at the level of single axons, providing context for white matter anisotropy and diffusivity estimates from previous DTI studies through values such as myelin thickness, area fraction, and axon trajectory. This structural framework of this pathway can be used to compare with results from in vivo imaging studies, and to provide a basis for comparison with pathological states in the future. / 2026-06-06T00:00:00Z
37

Walkability through Challenging terrain: Connectivity between Frederick Douglass National Historic Site and Anacostia Community Museum

Gelman, Daria Lvovna 17 August 2018 (has links)
This thesis is an investigation of how to achieve walkability over steep urban topography greater than Americans with Disabilities Act accessible 8.33% standard. I studied how landscape architects and architects have overcome challenging topography in a variety of international cities and how to increase connectivity in the steep terrain of Washington D.C.'s Anacostia neighborhood. Specifically, this thesis explores the roles of staircases in the city and how staircases can enhance the experience of moving through the city. Topographic changes can be an obstacle to walk on: the steeper the path the harder it is to move through it, which in turn may encourage a person to use a car to travel between low and high points in the city. My hypothesis is that steep topography can be an enhancement to walkability in the city. The experience of traveling through steep terrain is unique as it can provide visually engaging environment of walking, including expansive views of the city, engaging architecture, and physical exercise. To test this hypothesis, I designed two distinct routes over steep topography to connect the Frederick Douglass National Historic Site, the Smithsonian's Anacostia Community Museum, a sports field, and the Fort Stanton Recreation Center. The paths respond to L'Enfant's method for laying out the city in "diagonal avenues superimposed over a grid system" (Nps.gov, 2018) and the very steep terrain of Anacostia, which seems to defy in places the orthagonal and axial relationships underlying L'Enfant's plan. Drawing on both L'Enfant's ordering scheme of the city and the given form of the two hundred foot escarpment above Anacostia, the design demonstrates that paths through steep terrain can be a great asset, revealing the larger order of the city through views to the monumental core, bringing people through the native forest, making more direct connections between the civic infrastructure, including the Frederick Douglass National Historic Site and the Smithsonian's Anacostia Community Museum. It shows that expanding the notion of walkability to include terrain that is not ADA accessible is important, and can be the impetus for the strategic inclusion of accessible paths where the topography permits. / Master of Landscape Architecture / This thesis is an investigation of how to create walkable spaces over steep topography in Washington, D.C. By steep topography, I concentrated on grade changes that are greater than the steepest slopes allowed in construction so that anyone can access the site. I studied how landscape architects and architects have overcome challenging topography in a variety of international cities and how to increase connectivity in the steep terrain of Washington D.C.’s Anacostia neighborhood. Specifically, this thesis explores the roles of staircases in the city and how staircases can enhance the experience of moving through the city. Walkscore’s walkability map presents a unique view of the city where walkable parts follow the topography of the city. Topographic changes can be an obstacle to walk on: the steeper the path the harder it is to move through it, which in turn may encourage a person to use a car to travel between low and high points in the city. My hypothesis is that steep topography can be an enhancement to walkability in the city. The experience of traveling through steep terrain is unique as it can provide visually engaging environment of walking, including expansive views of the city, engaging architecture, and physical exercise. To test this hypothesis, I designed two distinct routes over steep topography to connect the Frederick Douglass National Historic Site, the Smithsonian’s Anacostia Community Museum, a sports field, and the Fort Stanton Recreation Center. The paths respond to the method for laying out the city in “diagonal avenues superimposed over a grid system” (Nps.gov, 2018) established by Pierre L’Enfant, the designer of Washington, D.C., over the steep terrain of Anacostia, which seems to defy in places the orthagonal and axial relationships underlying L’Enfant’s plan. Drawing on both L’Enfant’s ordering scheme of the city and the given form of the two hundred foot escarpment above Anacostia, the design demonstrates that paths through steep terrain can be a great asset, revealing the larger order of the city through views to the monumental core, bringing people through the native forest, making more direct connections between the civic infrastructure, including the Frederick Douglass National Historic Site and the Smithsonian’s Anacostia Community Museum. It shows that expanding the notion of walkability to include terrain that is not universally accessible is important, and can be the impetus for the strategic inclusion of accessible paths where the topography permits.
38

Model Updating Using a Quadratic Form

Tarazaga, Pablo Alberto 23 August 2004 (has links)
The research presented in this thesis addresses the problem of updating an analytical model using a parametric Reference Basis approach. In this method, some parameters are assumed to be accurate (e.g. natural frequencies, mode shapes and mass matrix), while others are adjusted so that the eigenvalue equation is satisfied. Updating is done with the use of principal submatrices, and the method seeks the best parameters multiplying these matrices. This is a departure from classical model reference, and is closer to the formulation of sensitivity methods. The submatrices allow updating of the stiffness matrix with certain freedom while preserving connectivity. Closed form solution can be achieved through multiple ways; two different approaches, denoted as the Quadratic Compression Method (QCM) and the Full Vector Method (FVM), are described in this paper. It is shown that the QCM possesses superior robustness properties with respect to noise in the data. This fact, as well as the simplicity offered by QCM, is demonstrated theoretically and experimentally. The experiments are presented to show the advantage of the QCM in the updating process. / Master of Science
39

Croatia at the Crossroads: A consideration of archaeological and historical connectivity

January 2016 (has links)
No / Croatia has a unique geographical and historical position within Europe, bridging central and south-east Europe. From the Pannonian Plain to the southern Adriatic maritime landscape, interconnectedness flows through Croatia's history. This dynamic past is increasingly being reflected upon by a new and exciting generation of Croatian scholars who are firmly embedded within a strong national tradition of archaeology but who also look outward to draw insights into the nature of material culture they encounter in Croatia and Croatian identity itself. Croatia at the Crossroads (24-25 June, Europe House, London) provided the opportunity to reflect upon such interconnectedness and Croatia's historic place within Europe. This event typified the desire of Croatian archaeologists to engage with such matters on an international level and to situate their scholarship within broader regional dynamics. Following the foundation of the new Croatian state, the opportunities for new forms of engagement have grown. This has stimulated thinking regarding both approaches to archaeology and the potential cultural cross-fertilisation that has resulted in Croatia's rich archaeological and historical record. This has led to in new, exciting understandings of archaeological material, and this was revealed in contributions to the Croatia at the Crossroads conference. The papers published here arise from the exceptionally interesting presentations and discussions held in London at the conference. Each of them takes Croatia's particular interconnectedness in terms of social and cultural relationships with the wider region as the starting point for exploring issues across a broad chronological range, from human origins to modernity. Within this, contributors pick up on a variety of different fields of interconnectedness and forms of interaction including biological, cultural, religious, military, trade, craft and maritime relationships. In many ways, these papers represent opening conversations that explore ways of thinking about new and established data sets that are entering Croatian scholarship for the first time. They also act as a set of complementary discussions that transcend traditional period and national boundaries. We hope that by bringing them together the volume will provide an insight into current trends in Croatian archaeology and stimulate fruitful discussions regarding future directions.
40

TELEMETRY IN BUNDLES: DELAY-TOLERANT NETWORKING FOR DELAY-CHALLENGED APPLICATIONS

Burleigh, Scott 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Delay-tolerant networking (DTN) is a system for constructing automated data networks in which end-to-end communication is reliable despite low data rates, possible sustained interruptions in connectivity, and potentially high signal propagation latency. As such it promises to provide an inexpensive and robust medium for returning telemetry from research vehicles in environments that provide meager support for communications: deep space, the surface of Mars, the poles or the sub- Arctic steppes of Earth, and others. This paper presents an overview of DTN concepts, including “bundles” and the Bundling overlay protocol. One possible scenario for the application of DTN to a telemetry return problem is described, and there is a brief discussion of the current state of DTN technology development.

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