230 research outputs found

    Visual analytics for the interpretation of fluency tests during Alzheimer evaluation

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    International audienceA possible way to evaluate the progress of Alzheimer disease is to conduct the Isaac set test [13, 14]. In this activity, patients are asked to cite the largest possible number of city names within a minute. Since the city names are handwritten very quickly by a medical practitioner some cities are abbreviated or poorly written. In order to analyze such data, medical practitioners need to digitize the notes first and clean the dataset. Because these tasks are intricate and error prone we propose a novel set of tools, involving interactive visualization techniques, to help medical practitioners in the digitization and data-cleaning process. This system will be tested as part of an ongoing longitudinal study involving 9500 patients

    Peacock Bundles: Bundle Coloring for Graphs with Globality-Locality Trade-off

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    Bundling of graph edges (node-to-node connections) is a common technique to enhance visibility of overall trends in the edge structure of a large graph layout, and a large variety of bundling algorithms have been proposed. However, with strong bundling, it becomes hard to identify origins and destinations of individual edges. We propose a solution: we optimize edge coloring to differentiate bundled edges. We quantify strength of bundling in a flexible pairwise fashion between edges, and among bundled edges, we quantify how dissimilar their colors should be by dissimilarity of their origins and destinations. We solve the resulting nonlinear optimization, which is also interpretable as a novel dimensionality reduction task. In large graphs the necessary compromise is whether to differentiate colors sharply between locally occurring strongly bundled edges ("local bundles"), or also between the weakly bundled edges occurring globally over the graph ("global bundles"); we allow a user-set global-local tradeoff. We call the technique "peacock bundles". Experiments show the coloring clearly enhances comprehensibility of graph layouts with edge bundling.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

    Broadening access to problem-based learning : design of the shell eco-marathon car-in-a-box concept

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    Abstract: Problem-based learning has proven to develop teamwork, problem solving skills, communication and critical thinking skills amongst learners. Due to these advantages, secondary schools in South Africa engage with problem-based events to promote the participation of learners in Science, Technology, Engineering and Mathematics (STEM). However, many schools face lack of time, lack of available funds and lack of the required technical skill set, which limits them from participating in these events. The Car-In-a-Box concept was developed to broaden access to a STEM problem-based learning event, called the Shell Eco-Marathon. The Car-In-A-Box concept addresses the three challenges that would normally prevent a school from entering the Shell Eco-Marathon, disenabling learners to harness the advantages of problem-based learning. The impact of the Car-In-A-Box concept for broadening access to problem-based learning is discussed

    Application opportunities of geographic information systems analysis to support achievement of the UNAIDS 90-90-90 targets in South Africa

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    In an effort to achieve control of the HIV epidemic, 90-90-90 targets have been proposed whereby 90% of the HIV-infected population should know their status, 90% of those diagnosed should be receiving antiretroviral therapy, and 90% of those on treatment should be virologically suppressed. In this article we present approaches for using relatively simple geographic information systems (GIS) analyses of routinely available data to support HIV programme management towards achieving the 90-90-90 targets, with a focus on South Africa (SA) and other high-prevalence settings in low- and middle-income countries. We present programme-level GIS applications to map aggregated health data and individual-level applications to track distinct patients. We illustrate these applications using data from City of Johannesburg Region D, demonstrating that GIS has great potential to guide HIV programme operations and assist in achieving the 90-90-90 targets in SA

    Palynostratigraphy and Bayesian Age Stratigraphic Model of New CA-ID-TIMS Zircon Ages from the Walloon Coal Measures, Surat Basin, Australia

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    The Surat Basin hosts significant coal and coal seam gas resources. New high-precision CA-TIMS U/Pb zircon ages from tuffs and Bayesian age stratigraphic models are combined with palynology from fine-grained sedimentary rocks and zircon trace elements to provide further chronostratigraphic and biostratigraphic constrains on the Walloon Coal Measures in the eastern margin of the Surat Basin and infer the palaeoenvironment and tectonic setting. The tuff ages range from 165.88 ± 0.11 Ma to 158.84 ± 0.05 Ma, with those from the stratigraphically lower Taroom Coal Measures ranging from 165.88 ± 0.11 to 163.05 ± 0.08 Ma and Juandah Coal Measures ranging from 159.91 ± 0.04 to 158.84 ± 0.05 Ma. This corroborates that the lower part of the Walloon Coal Measures is Callovian and the upper part is Oxfordian. The palynology results from mudstones show that all samples are dominated by microfossils of spore-pollen with conifers being the most abundant. Our samples fall withinPrice’s (1997) stratigraphic zonation of APJ4.2 and APJ4.3. Posterior ages for palynology samples were estimated through Bayesian age stratigraphic modelling using stratigraphic depths and U-Pb zircon ages. The palaeoenvironment in the eastern portion of the basin is inferred to be predominantly fluvial, with spores and pollen derived from fresh water or terrestrial plants. Higher concentrations of green algae in one sample suggest that at times the water was somewhat stagnant. The zircons were derived from predominantly intermediate magmas, as indicated by the generally low Ti, Ta, and Nb values. The tectonic environment that the zircons were derived from was most likely a continental subduction zone due to their high U/Yb, low Nb/Yb and relatively low Hf concentrations. These new data support previous conclusions of the Surat Basin palaeoenvironment, contribute to the ongoing discussion about the tectonic setting of the basin and add new regional age marker horizons

    Visual scanning as a reference framework for interactive representation design

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    International audienceWhen designing a representation, the designer implicitly formulates a sequence of visual tasks required to understand and use the representation effectively. This paper aims at making the sequence of visual tasks explicit in order to help designers elicit their design choices. In particular, we present a set of concepts to systematically analyse what a user must theoretically do to decipher representations. The analysis consists of a decomposition of the activity of scanning into elementary visualization operations. We show how the analysis applies to various existing representations, and how expected benefits can be expressed in terms of elementary operations. The set of elementary operations form the basis of a shared language for representation designers. The decomposition highlights the challenges encountered by a user when deciphering a representation and helps designers to exhibit possible flaws in their design, justify their choices, and compare designs. We also show that interaction with a representation can be considered as facilitation to perform the elementary operations

    CHICAGO AIR POLLUTION SYSTEMS ANALYSIS PROGRAM. LONG-RANGE PLANNING IN AIR RESOURCE MANAGEMENT.

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