7 research outputs found

    High Resolution Imaging and the Formation of Stars and Planets

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    Understanding the formation of stellar and planetary systems is one of the great challenges of contemporary astrophysics. This thesis describes progress towards understanding these processes, through advancement of techniques to enable high resolution imaging of faint companions and other structures in the immediate environs of young stars. To ensure optimal performance in an era of large segmented telescopes, techniques to precisely cophase the mirror segments are required. In this thesis we propose the Fizeau Interferometric Cophasing of Segmented Mirrors algorithm, and present the results of testing both numerically and through experiment. We help to rectify a lack of observational evidence with which to test brown dwarf evolutionary models, by laying the foundation for an orbital monitoring survey of 19 brown dwarf binary systems and reporting the discovery of an additional 7 low mass companions to intermediate mass stars. We perform a Non-Redundant Masking (NRM) survey targeting the 1\,Myr old Ophiuchus star forming region. Both binary statistics and the relationship between multiplicity and the presence of a circumstellar disk are explored, providing many results similar to those from older regions. This helps frame the time evolution of effects related to dynamical interactions in binary systems, and the timescale of disk dissipation, with profound implications for giant planet formation. In thesis we also present the results of commissioning for the Gemini Planet Imager Non-Redundant Masking mode. These results indicate that the addition of an Extreme Adaptive Optics systems has substantially improved the performance of NRM compared to previous instruments. Finally, the transition disk T Cha is studied with multi-epoch NRM data, showing that the signal previously interpreted as a planetary companion is more likely to be the result of forward scattering from the inclined outer disk

    Formal Foundations of Patient Case Analysis

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    Computerized charting of case reports

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    Progress with formalization in medical informatics?

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    The prevailing view of medical informatics as a primarily subservient discipline in health care is challenged. Developments in both general informatics and medical informatics are described to identify desirable properties of modeling languages and tools needed to solve key problems in the application field. For progress in medical informatics, it is considered essential to develop far more formal modeling languages, modeling techniques, and tools. A major aim of this development should be to expel ambiguity from concepts essential to medicine, positioning medical informatics "at the heart of health care.

    Requirements for medical modeling languages.

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    OBJECTIVE: The development of tailor-made domain-specific modeling languages is sometimes desirable in medical informatics. Naturally, the development of such languages should be guided. The purpose of this article is to introduce a set of requirements for such languages and show their application in analyzing and comparing existing modeling languages. DESIGN: The requirements arise from the practical experience of the authors and others in the development of modeling languages in both general informatics and medical informatics. The requirements initially emerged from the analysis of information modeling techniques. The requirements are designed to be orthogonal, i.e., one requirement can be violated without violation of the others. RESULTS: The proposed requirements for any modeling language are that it be "formal" with regard to syntax and semantics, "conceptual," "expressive," "comprehensible," "suitable," and "executable." The requirements are illustrated using both the medical logic modules of the Arden Syntax as a running example and selected examples from other modeling languages. CONCLUSION: Activity diagrams of the Unified Modeling Language, task structures for work flows, and Petri nets are discussed with regard to the list of requirements, and various tradeoffs are thus made explicit. It is concluded that this set of requirements has the potential to play a vital role in both the evaluation of existing domain-specific languages and the development of new ones

    Archaeological communication and digital technology: Interview Transcript 19

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    This dataset is part of Sarah Colley's research project Mediated Messages: Archaeology Communication and Digital Technology (2010-2015) which investigates philosophical and ethical questions raised by using digital communication technology in archaeology and cultural heritage practice (e.g. Colley 2013, 2015). In 2011 Colley interviewed thirty Australian-based archaeologists and cultural heritage professionals about their use of digital technology and their communication with professional peers; television, radio and newspaper journalists; public relations and online media practitioners; public and government organisations; businesses; and members of the wider public including Indigenous community members and traditional owners. The research provides insights into e.g. remediation political economy, technology design, representation, authenticity and digital literacy. Changing communication technologies impact on peoples' understanding of and reactions to physical remains of the human past in ways that have broader social political and economic implications
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