Brandon Pincombe

Theoretical modeling of micro-scale biological phenomena in human coronary arteries

This paper presents a mathematical model of biological structures in relation to coronary arteries with atherosclerosis. A set of equations has been derived to compute blood flow through these transport vessels with variable axial and radial geometries. Three-dimensional reconstructions of diseased arteries from cadavers have shown that atherosclerotic lesions spiral through the artery. The theoretical framework is able to explain the phenomenon of lesion distribution in a helical pattern by examining the structural parameters that affect the flow resistance and wall shear stress. The study is useful for connecting the relationship between the arterial wall geometries and hemodynamics of blood. It provides a simple, elegant and non-invasive method to predict flow properties for geometrically complex pathology at micro-scale levels and with low computational cost.

An assessment of email and spontaneous dialog visualizations

Two experiments were conducted examining the effectiveness of visualizations of unstructured texts. The first experiment presented transcriptions of unrehearsed dialog and the second used emails. Both experiments showed an advantage in overall performance for semantically structured two-dimensional (2D) spatialized layouts, such as multidimensional scaling (MDS), over structured and non-structured list displays. The second experiment also demonstrated that this advantage is not simply due to the 2D nature of the display, but the combination of 2D display and the semantic structure underpinning it. Without this structure, performance fell to that of a Random List of documents. The effect of document type in this study and in Butavicius and Lees (2007) study on visualizations of news articles may be partly described by a change in bias on a speed-accuracy trade-off. At one extreme, users were accurate but slow in answering questions based on the dialog texts while, at the other extreme, users were fast but relatively inaccurate when responding to queries about emails. Similarly, users could respond accurately using the non-structured list interface; however, this was at the cost of very long response times and was associated with a technique whereby participants navigated by clicking on neighboring document representations. Implications of these findings for real-world applications are discussed.

Scoping a flexible deployment framework using adversarial scenario analysis

To aid with Australian Army deployment planning we propose a flexible deployment concept developed using adversarial scenario analysis. This novel technique begins with a simple scenario and a core strategy. Iteratively, the scenario is modified to defeat the existing strategy and the strategy is altered to cope. This process results in the deployed force being structured as a set of cohesive functional teams that provide emotional support to their members, suffer stress at different rates and are able to be rotated independently of each other. An accumulator model of deployment stress is assumed and continuous time-in-theatre is minimised subject to realistic constraints. The concept is focused on stable long term commitments to small wars, insurgencies and peacekeeping operations within four time-zones of the deployment source and with forward bases near usable airfields. To plan specific deployments, the same process could be expanded upon with appropriate detail.