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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.
381

Virtual reconstruction of a seventeenth-century Portuguese nau

Wells, Audrey Elizabeth 10 October 2008 (has links)
This interdisciplinary research project combines the fields of nautical archaeology and computer visualization to create an interactive virtual reconstruction of the 1606 Portuguese vessel Nossa Senhora dos Mártires, also known as the Pepper Wreck. Using reconstruction information provided by Dr. Filipe Castro (Texas A&M Department of Anthropology), a detailed 3D computer model of the ship was constructed and filled with cargo to demonstrate how the ship might have been loaded on the return voyage from India. The models are realistically shaded, lighted, and placed into an appropriate virtual environment. The scene can be viewed using the real-time immersive and interactive system developed by Dr. Frederic Parke (Texas A&M Department of Visualization). The process developed to convert the available information and data into a reconstructed 3D model is documented. This documentation allows future projects to adapt this process for other archaeological visualizations, as well as informs archaeologists about the type of data most useful for computer visualizations of this kind.
382

AN ADAPTIVE SAMPLING APPROACH TO INCOMPRESSIBLE PARTICLE-BASED FLUID

Hong, Woo-Suck 16 January 2010 (has links)
I propose a particle-based technique for simulating incompressible uid that includes adaptive re nement of particle sampling. Each particle represents a mass of uid in its local region. Particles are split into several particles for ner sampling in regions of complex ow. In regions of smooth ow, neghboring particles can be merged. Depth below the surface and Reynolds number are exploited as our criteria for determining whether splitting or merging should take place. For the uid dynamics calculations, I use the hybrid FLIP method, which is computationally simple and e cient. Since the uid is incompressible, each particle has a volume proportional to its mass. A kernel function, whose e ective range is based on this volume, is used for transferring and updating the particle's physical properties such as mass and velocity. In addition, the particle sampling technique is extended to a fully adaptive approach, supporting adaptive splitting and merging of uid particles and adaptive spatial sampling for the reconstruction of the velocity and pressure elds. Particle splitting allows a detailed sampling of uid momentum in regions of complex ow. Particle merging, in regions of smooth ow, reduces memory and computational overhead. An octree structure is used to compute inter-particle interactions and to compute the pressure eld. The octree supporting eld-based calculations is adapted to provide a ne spatial reconstruction where particles are small and a coarse reconstruction where particles are large. This scheme places computational resources where they are most needed, to handle both ow and surface complexity. Thus, incompressibility can be enforced even in very small, but highly turbulent areas. Simultaneously, the level of detail is very high in these areas, allowing the direct support of tiny splashes and small-scale surface tension e ects. This produces a nely detailed and realistic representation of surface motion.
383

Effect of Different Flow-Fields on £gDMFC Performance

Chen, Wei-chih 23 July 2009 (has links)
In this study, cell performance tests and measurements of the pressure drop in the anode flow channels of a micro methanol fuel cell (£gDMFC) were conducted. The effect of different operating parameters on £gDMFC performance was experimentally investigated for serpentine flow-field configuration. Experiments were conducted through a serious experiments with different operating conditions of temperature (40¡B60¡B70¡B80oC)¡Bmethanol concentration (0.5¡B1¡B1.5¡B2 M)¡Bchannel width (0.5¡B0.6¡B0.7¡B0.8¡B1¡B1.5¡B2 mm) and flow rate (10-20 sccm). Experimental results are presented in the form of polarization VI curves and PI curves under above operating conditions. The experimental results show that the pressure drop decrease with increasing current density. It has also shown that the pressure drop always increased with the methanol solution flow rates. The relationship between pressure drop and CO2 bubbles production rate would change with the current density increase. Finally, an optimal channel size of 700 £gm for the present £gDMFC could be obtained.
384

Visibility Visualization And Haptic Path Exploration

Manohar, B S 06 1900 (has links)
We propose a real-time system to visualize multi-viewpoint visibility information for terrains, supporting flight path optimization for view coverage or vehicle exposure to ground. A volume rendered display and a haptic interface assist the user in selecting, assessing, and refining the computed flight path. We construct a three-dimensional scalar field representing the visibility of a point above the terrain, describe an efficient algorithm to compute visibility, and develop visual and haptic schemes to interact with the visibility field. Given the origin and destination, the desired flight path is computed using an efficient simulation of an articulated rope under the influence of the visibility gradient. The simulation framework also accepts user input, via the haptic interface, thereby allowing manual refinement of the flight path.
385

Physical Simulation and Visualization of Cells

Nilsson, Johannes January 2008 (has links)
<p>Multicellular organisms develop from a single cell by repeated cell division and cell differentiation. This report presents a computer program for simulating dividing cells. The program simulates a single cell that goes through a series of divisions to create a small organism.</p><p>The evolving organism can be visualized both in a 3D view and in a lineage tree structure that shows the cell heradity. Information about both final cells and intermediary cells is easily available for the user.</p><p>A method for fast physical simulation of soft bodies based on a mass-spring system combined with a pressure model is used to simulate the physical properties of the cells. Fast collision detection for soft bodies is achieved using hierarchical tree structure of axis aligned bounding boxes combined with an implicit penetration depth definition.</p><p>Biological control of cell division and differentiation is simulated using a model where the state of each cell is represented by as a vector of substances present in the cell. The cell state is updated at discrete time steps by a model of DNA transcription.</p>
386

Visualization of Text Duplicates in Documents

Wang, Chao, Pan, Han January 2009 (has links)
<p>In this thesis, a tool to visualize duplicate parts in a series of given documents is developed.</p><p>Text duplicates are very common nowadays in all fields. This behavior severelyharms the rights of the original authors though it facilitates the work of those whocopy from them. Effective legal measures have been taken when it comes to copyrightissue. An increasing large number of people have paid serious attention to what theywrite when they refer to other people's works. Although references are properly madeby many who admire and respect others' achievements, plagiarism takes place all thetime. Therefore, an intuitive way of visualizing duplicate parts is needed so thatpeople can easily grasp the purpose and decide the legality of those duplicates. Whenit comes to computer science, software clone is very typical phenomenon amongdifferent development groups or even within one group. Since a piece of softwareusually have its hierarchy, it is also interesting to group members when they do aclone detection of their own or other software. For example, if a good overview of thehierarchies is provided in a tree representation, one can easily locate the clones of aparticular node in other trees. More interaction techniques can allow concrete codeaccesses through double clicking on a highlighted node.</p><p>To visualize duplicate parts in a nice and intuitive way, a visualization tool isdeveloped for this thesis project. By the time it is done, the following features shouldbe fulfilled. First, the tool can visualize similar or identical parts given a data set.Second, hierarchies of those files can be demonstrated with proper layout. Third, theuser can manipulate the data items on the screen in order to get a better insight of thedata set and help with analysis tasks. Forth, different levels of abstraction areprovided so that the user can either get an overview of all the files or specificallycheck the duplicate parts in the documents of interest.</p> / Visualization of Text Duplicates in Documents
387

How information visualization systems change users' understandings of complex data /

Allendoerfer, Kenneth Robert. Chen, Chaomei, January 2009 (has links)
Thesis (Ph.D.)--Drexel University, 2009. / Includes abstract and vita. Includes bibliographical references (leaves 207-216).
388

A cognition-based framework for the development of visualization literacy

Velez-Rojas, Maria C., January 2009 (has links)
Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Electrical and Computer Engineering." Includes bibliographical references (p. 140-146).
389

Mental Image Manipulation and Math: An Investigation into the Influence of Visualization and Mental Rotation on Math Performance

Oehlert, Jeremy January 2010 (has links)
Thesis(M.A.)--Case Western Reserve University, 2010 / Title from PDF (viewed on 2010-01-28) Department of Psychology Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
390

Individual differences in information seeking the effects and interaction of spatial, visualization and domain expertise /

Downing, Ricard E. January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 86-95). Also available on the Internet.

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