Doctor of Philosophy (PhD)
Time-varying three-dimensional positional atomistic data are rich in spatial and temporal information. The problem is to understand them. This work offers multiple approaches that enable such understanding. An interactive atomistic visualization system is developed integrating complex analyses with visualization to present the data on space-time multiresolution basis facilitating the information extraction and generate understanding. This work also shows the usefulness of such an integrated approach. The information obtained from the analyses represents the system at multiple length and time scales. Radial distribution function (RDF) provides a complete average spatial map of the distribution of the atoms in the system which is probed to explore the system at different length scales. Coordination environments and cluster structures are visualized to look at the short range structures. Rings are visualized to understand the medium range structure. Displacement data and covariance matrices are visualized to understand the dynamical behaviors. Combinations of rendering techniques including animation, color map, sphere, polygonal and ellipsoid representations, pathlines and glyphs are used during the visualization process. The three-dimensional atomic configurations are reproduced accurately during rendering because of their physical significance while attributes such as coordination number, coordination stability and atomic species lack direct physical relevance and provide additional flexibilities in rendering. The performance results show interactive frame rates are achievable for systems consisting upto a thousand atoms. Such systems are typical of the systems simulated using first principles molecular dynamics simulations. The effectiveness and the usefulness of this work are justified for complex material systems using silicate and oxide liquids for visual analyses. The exploratory approach taken here has not been reported anywhere else before. The major contributions of this works are: 1. A new approach to the atomistic visualization advocating a formal integration of data analyses into the visualization system to improve the effectiveness and also present an implementation of the exploratory atomistic visualization system with integrated spatio-temporal analytical techniques. 2. The modeling of coordination environments, stability of the coordination environments, clusters, ring structures and diffusion for individual atoms. 3. The use of the visualization system for visual analysis of various liquid mineral systems of geophysical relevance.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Bhattarai, Dipesh, "Space-time multiresolution approach to atomistic visualization" (2008). LSU Doctoral Dissertations. 3143.
Bijaya B. Karki