published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy

In this survey article, we review glyph-based visualization techniques, which have been exploited when visualizing spatial multivariate medical data. To classify these techniques, we derive a taxonomy of glyph properties, which is based on classification concepts established in information visualization. By considering both the glyph visualization as well as the interaction techniques that are employed to generate or explore the glyph visualization, we are able to classify glyph techniques into two main groups: those supporting pre-attentive and those supporting attentive processing. With respect to this classification, we review glyph-based techniques described in the medical visualization literature. Based on the outcome of the literature review, we propose design guidelines for glyph visualizations in the medical domain.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 189-194) Also available in print.

Traditional visualization techniques for multidimensional data sets, such as parallel coordinates, star glyphs, and scatterplot matrices, do not scale well to high dimensional data sets. A common approach to solve this problem is dimensionality reduction. Existing dimensionality reduction techniques, such as Principal Component Analysis, Multidimensional Scaling, and Self Organizing Maps, have serious drawbacks in that the generated low dimensional subspace has no intuitive meaning to users. In addition, little user interaction is allowed in those highly automatic processes. In this thesis, we propose a new methodology to dimensionality reduction that combines automation and user interaction for the generation of meaningful subspaces, called the visual hierarchical dimension reduction (VHDR) framework. Firstly, VHDR groups all dimensions of a data set into a dimension hierarchy. This hierarchy is then visualized using a radial space-filling hierarchy visualization tool called Sunburst. Thus users are allowed to interactively explore and modify the dimension hierarchy, and select clusters at different levels of detail for the data display. VHDR then assigns a representative dimension to each dimension cluster selected by the users. Finally, VHDR maps the high-dimensional data set into the subspace composed of these representative dimensions and displays the projected subspace. To accomplish the latter, we have designed several extensions to existing popular multidimensional display techniques, such as parallel coordinates, star glyphs, and scatterplot matrices. These displays have been enhanced to express semantics of the selected subspace, such as the context of the dimensions and dissimilarity among the individual dimensions in a cluster. We have implemented all these features and incorporated them into the XmdvTool software package, which will be released as XmdvTool Version 6.0. Lastly, we developed two case studies to show how we apply VHDR to visualize and interactively explore a high dimensional data set.

<p>In this thesis, a 3D approach to visualize software metrics is presented. Software metrics are attributes of a piece of software or its specification. They generally contain a set of multivariate time-series data and can be displayed, for example, as a Kiviat diagram consisting of axes and polylines. The aim of this work is to design a Win32 application that can load multivariate time-series data from a file and visualize it as an interactive 3D Kiviat diagram.</p><p>There has been an approach that can display software metrics by using 2D Kiviat diagrams, but there are still some drawbacks on it. Since a better visualization of software metrics can help the developer to control the quality of software products more easily, this thesis improved the existing approach by extending 2D Kiviat diagram to 3D Kiviat diagram.</p>

No description available.

This thesis investigates how users contribute to wiki environments implemented in higher education settings. The type, extent and quality of users' edits is assessed by analyzing a student-generated wiki through a manual analysis carried by three raters. This project aims to present the relative contribution of wiki users as a way to motivate them to collaborate in a wiki-based group project. Manual as well as automatic programs are used to analyze the same set of wiki articles. Automatic algorithms are proposed to estimate users' relative contribution and ownership to the article. Suggested is the implementation of a visual representation known as a glyph (working as an add-on to the wiki) that shows statistics on participants contributions. Several glyph designs were tested by participants through interviews. These interviews showed that participants identified the visualization as a motivation enhancer to contribute to wikis.

In this thesis, a 3D approach to visualize software metrics is presented. Software metrics are attributes of a piece of software or its specification. They generally contain a set of multivariate time-series data and can be displayed, for example, as a Kiviat diagram consisting of axes and polylines. The aim of this work is to design a Win32 application that can load multivariate time-series data from a file and visualize it as an interactive 3D Kiviat diagram. There has been an approach that can display software metrics by using 2D Kiviat diagrams, but there are still some drawbacks on it. Since a better visualization of software metrics can help the developer to control the quality of software products more easily, this thesis improved the existing approach by extending 2D Kiviat diagram to 3D Kiviat diagram.

<p>This project presents the research on software visualization techniques. We will introduce the concepts of software visualization, software metrics and our proposed visualization techniques: Static Visualization (glyphs object with static texture) and Dynamic Visualization (glyphs object with moving object). Our intent to study the existing visualization techniques for visualization of software</p><p>metrics and then proposed the new visualization approach that is more time efficient and easy to perceive by viewer. In this project, we focus on the practical aspects of visualization of multivariate dataset. This project also gives an implementation of proposed visualization techniques of software metrics. In this research based work, we have to compare practically the proposed visualization approaches. We will discuss the software development life cycle of our proposed visualization system, and we will also describe the complete software implementation of implemented software.</p>

This project presents the research on software visualization techniques. We will introduce the concepts of software visualization, software metrics and our proposed visualization techniques: Static Visualization (glyphs object with static texture) and Dynamic Visualization (glyphs object with moving object). Our intent to study the existing visualization techniques for visualization of software metrics and then proposed the new visualization approach that is more time efficient and easy to perceive by viewer. In this project, we focus on the practical aspects of visualization of multivariate dataset. This project also gives an implementation of proposed visualization techniques of software metrics. In this research based work, we have to compare practically the proposed visualization approaches. We will discuss the software development life cycle of our proposed visualization system, and we will also describe the complete software implementation of implemented software.