An Advanced, Three-Dimensional Plotting Library for Astronomy

We present a new, three-dimensional (3D) plotting library with advanced features, and support for standard and enhanced display devices. The library - S2PLOT - is written in C and can be used by C, C++ and FORTRAN programs on GNU/Linux and Apple/OSX systems. S2PLOT draws objects in a 3D (x,y,z) Cartesian space and the user interactively controls how this space is rendered at run time. With a PGPLOT inspired interface, S2PLOT provides astronomers with elegant techniques for displaying and exploring 3D data sets directly from their program code, and the potential to use stereoscopic and dome display devices. The S2PLOT architecture supports dynamic geometry and can be used to plot time-evolving data sets, such as might be produced by simulation codes. In this paper, we introduce S2PLOT to the astronomical community, describe its potential applications, and present some example uses of the library.Comment: 12 pages, 10 eps figures (higher resolution versions available from http://astronomy.swin.edu.au/s2plot/paperfigures). The S2PLOT library is available for download from http://astronomy.swin.edu.au/s2plo

Distributed object-oriented discrete event simulation

This paper presents criteria for an \u27ideal\u27 simulation language, compares four traditional simulation languages to this ideal and concludes that an object-oriented approach to simulation comes closer to the ideal than the traditional procedural approach. It also examines how the object-oriented approach can be very beneficial for distributing a simulation problem among several machines. A distributed object-oriented package is described and a manufacturing example written and explained using this package

Countering student 'instrumentalism' through creative mediation

One of the most significant features of the educational reforms introduced since 1989 has been the emphasis on raising achievement levels. One of the dangers of this emphasis is that teachers and learners become instrumental in their approach to teaching and learning. Research on the creative mediation of policy shows that primary teachers appropriate reforms and adapt them to ensure a high level of learner involvement in learning. This pilot study of three Year 5 and 6 classes focuses on the creative teaching strategies used to maintain learner involvement in the wake of all the reforms of the 1990s. In particular, the study uses learner perspectives as a major part of the data set. The tentative conclusions are that the clarification of learning objectives with the learners and the reconstruction of appropriate creative learning contexts has had an effect in countering learner instrumentalism. These approaches were effective in developing learners' awareness of the learning process and enabled them to articulate perspectives concerning those processes. However, the study did not find much evidence of teachers incorporating these learner perspectives into their curriculum and pedagogic programmes

Nodal Discontinuous Galerkin Methods on Graphics Processors

Discontinuous Galerkin (DG) methods for the numerical solution of partial differential equations have enjoyed considerable success because they are both flexible and robust: They allow arbitrary unstructured geometries and easy control of accuracy without compromising simulation stability. Lately, another property of DG has been growing in importance: The majority of a DG operator is applied in an element-local way, with weak penalty-based element-to-element coupling. The resulting locality in memory access is one of the factors that enables DG to run on off-the-shelf, massively parallel graphics processors (GPUs). In addition, DG's high-order nature lets it require fewer data points per represented wavelength and hence fewer memory accesses, in exchange for higher arithmetic intensity. Both of these factors work significantly in favor of a GPU implementation of DG. Using a single US$400 Nvidia GTX 280 GPU, we accelerate a solver for Maxwell's equations on a general 3D unstructured grid by a factor of 40 to 60 relative to a serial computation on a current-generation CPU. In many cases, our algorithms exhibit full use of the device's available memory bandwidth. Example computations achieve and surpass 200 gigaflops/s of net application-level floating point work. In this article, we describe and derive the techniques used to reach this level of performance. In addition, we present comprehensive data on the accuracy and runtime behavior of the method.Comment: 33 pages, 12 figures, 4 table

Investigating microstructural variation in the human hippocampus using non-negative matrix factorization

In this work we use non-negative matrix factorization to identify patterns of microstructural variance in the human hippocampus. We utilize high-resolution structural and diffusion magnetic resonance imaging data from the Human Connectome Project to query hippocampus microstructure on a multivariate, voxelwise basis. Application of non-negative matrix factorization identifies spatial components (clusters of voxels sharing similar covariance patterns), as well as subject weightings (individual variance across hippocampus microstructure). By assessing the stability of spatial components as well as the accuracy of factorization, we identified 4 distinct microstructural components. Furthermore, we quantified the benefit of using multiple microstructural metrics by demonstrating that using three microstructural metrics (T1-weighted/T2-weighted signal, mean diffusivity and fractional anisotropy) produced more stable spatial components than when assessing metrics individually. Finally, we related individual subject weightings to demographic and behavioural measures using a partial least squares analysis. Through this approach we identified interpretable relationships between hippocampus microstructure and demographic and behavioural measures. Taken together, our work suggests non-negative matrix factorization as a spatially specific analytical approach for neuroimaging studies and advocates for the use of multiple metrics for data-driven component analyses

Beyond the Neuro-Realism Fallacy : From John R. Mallard’s Hand-painted MRI Image of a Mouse to BioArt Scenarios

This publication was made possible thanks to the generous support of the Carnegie Trust (Research Incentive Grants).Peer reviewedPostprin

Musica Universalis : the pursuit of pure abstraction

The thesis exhibition, Musica Universalis, is a multi-sensory exhibition comprised of experimental weavings on deconstructed found pianos, systematic drawings, and paper scroll music boxes. The music boxes allow the viewer to hear the voice part represented on the weaving, or the notes of a systematic drawing, in isolation; a recording of a choral composition transcribed from the first systematic drawing of circles plays from the gallery speakers. The viewer can hear the individual's "song" and simultaneously hear the collective performance. The performance of the collective music box composition varies depending on the level of viewer engagement. I create system-based abstractions drawing from my understanding of structure within music and weaving, as well as analog and digital technologies, to achieve a purer abstraction. For the purposes of this paper, I define abstraction as artwork that reshapes the natural world for expressive purposes, interpreting expressive as relating to intuition, emotions and the subconscious. Therefore, I characterize pure abstraction as work that directly resonates within the viewer's soul or subconscious, having meaning that reaches beyond what is visible. I look to Wassily Kandinsky's Compositions and Paul Klee's Rhythmisches as case studies for the pursuit of pure abstraction, in which they drew from the formal qualities and conventions of Western music aesthetics to inform their visual abstractions. My response to their projects is to present work in which the visual and aural elements are of equal importance. This thesis briefly visits the projects of Kandinsky and Klee as they influenced the development of the immersive exhibition and documents the many facets to the viewer's experience within Musica Universalis.by Erin Kathleen KingIncludes bibliographical reference

Tapestries of Innovation: Structures of Contemporary Open Source Project Engagements

Since the origins of the free-software movement, open source projects have fostered an environment for innovative ideas that has transformed much of our understanding of technology in everyday life. In our quest to learn more about the structures of large-scale contemporary open source engagements, we examine three open source networks as part of an ongoing field study (Van Maanen, 2011). We explore the innovation networks described by Lyytinen, Yoo, & Boland (2016) and resolve whether any of the open source innovative networks that we have been studying can be classified as Project, Clan, Federated, or Anarchic networks. We examine two collaborative open source projects (SPDX and OpenMAMA) housed at the Linux Foundation, and determine that they correspond to the Federated and Project innovation networks respectively. Further, we determined that the Linux Foundation itself, as an organization that houses numerous open source projects, did not fit any of the four types of networks. We therefore propose and authenticate a fifth type of network that we characterize as a Tapestry innovation network, which can illuminate the Linux Foundation’s complexity of horizontal “weft threads” of participating organizations with the vertical, less visible “warp threads” of responsibilities and endeavors. Our study reveals important implications for research and practice by challenging the accepted view of open source projects, which still largely regards engagement around loosely structured groups of volunteers working on publicly available software. It also reveals that foundations are playing increasingly strategic roles in creating and stabilizing open source projects