76,096 research outputs found

    New technology for interactive CAL: The origami project

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    Origami is a three‐year EPSRC project that forms part of a general research programme on human‐computer interaction. The goal of this research is to investigate and implement new methods for human‐computer interaction, and to apply and evaluate their use. The research centres on the DigitalDesk, an ordinary desk augmented with a computer display using projection television and a video camera to monitor inputs. The DigitalDesk allows electronic and printed documents to be combined to give richer presentation and interaction possibilities than are possible with either separate medium. This paper examines the implications of such a system for CAL, and presents two prototype applications that demonstrate the possibilities

    Enriching accounts of computer‐supported collaboration by using video data

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    This paper will discuss the approach to the evaluation of computer‐supported collaborative learning developed in our group over the past ten years. This approach depends on the collection of video data to allow the analysis of key features of problem‐solving behaviour within groups of students working on collaborative learning tasks. Our theoretical framework derives from two sources‐ the CIAOl framework for evaluating examples of CAL and an analysis of appropriate methods of evaluating computer‐supported collaboration. Our work in this area has been supported by developing the data capture facilities for the CALRG (Computers and Learning Research Group) at the Open University. We will draw on a number of studies to illustrate this approach and will present a brief case study from work done on a computer‐supported learning environment for statistics where we use video records of video‐mediated collaboration. This case study gives an example of the rich data that can be collected using video recording and analysed to increase understanding of computer‐supported collaboration

    Lagrangian ADER-WENO Finite Volume Schemes on Unstructured Triangular Meshes Based On Genuinely Multidimensional HLL Riemann Solvers

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    In this paper we use the genuinely multidimensional HLL Riemann solvers recently developed by Balsara et al. to construct a new class of computationally efficient high order Lagrangian ADER-WENO one-step ALE finite volume schemes on unstructured triangular meshes. A nonlinear WENO reconstruction operator allows the algorithm to achieve high order of accuracy in space, while high order of accuracy in time is obtained by the use of an ADER time-stepping technique based on a local space-time Galerkin predictor. The multidimensional HLL and HLLC Riemann solvers operate at each vertex of the grid, considering the entire Voronoi neighborhood of each node and allows for larger time steps than conventional one-dimensional Riemann solvers. The results produced by the multidimensional Riemann solver are then used twice in our one-step ALE algorithm: first, as a node solver that assigns a unique velocity vector to each vertex, in order to preserve the continuity of the computational mesh; second, as a building block for genuinely multidimensional numerical flux evaluation that allows the scheme to run with larger time steps compared to conventional finite volume schemes that use classical one-dimensional Riemann solvers in normal direction. A rezoning step may be necessary in order to overcome element overlapping or crossing-over. We apply the method presented in this article to two systems of hyperbolic conservation laws, namely the Euler equations of compressible gas dynamics and the equations of ideal classical magneto-hydrodynamics (MHD). Convergence studies up to fourth order of accuracy in space and time have been carried out. Several numerical test problems have been solved to validate the new approach
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