9,089 research outputs found
Being subject-centred: A philosophy of teaching and implications for higher education
Being subject-centred as a higher education teacher offers a rich and illuminating philosophical and practical understanding of learning. Building upon previous research on subject-centred learning, we draw on reflection, literature review and a phenomenological approach to show how our ways of being infuse the teaching and learning environment. Philosophically, it is our way of being with our subject as teachers that influences the learning within our students. We show how posing the question: 'What is the best way to teach this subject?' helps a teacher find the best way to enhance the learning experience. It entails moving away from reliance solely on approaches that simply 're-present' content, such as lectures and online learning management systems, to interactive classrooms where space is created for the students to enter into their own engagement with the subject in a shared pursuit with the teacher, resulting in more effective teaching and learning. We illustrate this with personal accounts of our own journeys as teachers. We acknowledge that it takes courage to teach and to fully be subject-centred in the face of prevailing trends and pressures for other ways of teaching currently prominent in the higher education sector. But, ultimately, it is who we are as teachers that matters most, and being subject-centred provides the most effective way for us to most meaningfully reach our students
Challenges in using GPUs for the real-time reconstruction of digital hologram images
This is the pre-print version of the final published paper that is available from the link below.In-line holography has recently made the transition from silver-halide based recording media, with laser reconstruction, to recording with large-area pixel detectors and computer-based reconstruction. This form of holographic imaging is an established technique for the study of fine particulates, such as cloud or fuel droplets, marine plankton and alluvial sediments, and enables a true 3D object field to be recorded at high resolution over a considerable depth.
The move to digital holography promises rapid, if not instantaneous, feedback as it avoids the need for the time-consuming chemical development of plates or film film and a dedicated replay system, but with the growing use of video-rate holographic recording, and the desire to reconstruct fully every frame, the computational challenge becomes considerable. To replay a digital hologram a 2D FFT must be calculated for every depth slice desired in the replayed image volume. A typical hologram of ~100 μm particles over a depth of a few hundred millimetres will require O(10^3) 2D FFT operations to be performed on a hologram of typically a few million pixels.
In this paper we discuss the technical challenges in converting our existing reconstruction code to make efficient use of NVIDIA CUDA-based GPU cards and show how near real-time video slice reconstruction can be obtained with holograms as large as 4096 by 4096 pixels. Our performance to date for a number of different NVIDIA GPU running under both Linux and Microsoft Windows is presented. The recent availability of GPU on portable computers is discussed and a new code for interactive replay of digital holograms is presented
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Off-axis transmission holographic system for recording aquatic particles
We describe a holographic system for recording particles suspended in water. The hologram plate is located in air, separated from the test tank by an air/glass/water boundary. The holographic emulsion is therefore unaffected by adverse aquatic conditions within the tank (i.e. surface contamination, non-uniform swelling). The design geometry is intended to minimise the aberrations that arise from recording subjects located in water and replaying their hologram image in air.
Third order aberrations, most crucially spherical aberration and astigmatism, are suppressed to give an experimental resolution of 7 lp/mm using USAF 1951 target in water 600mm from the boundary. Particles (plankton species) in the
sub-millimeter to several millimeters size range are observed at planar sections within the recording volume by visual inspection of the hologram replayed in real image mode
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Holographic mensuration of suspended particles in aquatic systems
The distribution and dynamics of aggregates in the aquatic environment play an important role in the modelling of biogeochemical processes. Previous work on aggregates in the ocean (e.g. sedimentary 'marine snow' particles), which vary in size from tens of microns to several millimetres, has used electronic counting or conventional photography coupled with image analysis. Here we describe a non-destructive in situ approach by use of holographic mensuration, hologrammetry, that affords greater scope and higher accuracy for the enumeration, sizing, and spatial distribution determination of aggregate particles. By means of two complimentary techniques, in-line and offaxis transmission holography, we present the initial experiments conducted in our laboratory and discuss the preliminaiy results from real image analysis
Support for the Ethiopian Health Sector Development Programme (Federal Ministry of Health MDG Performance Fund)
This Annual Review draws on the findings of the HSDP IV Mid Term Review (MTR),
the FMOH’s Annual Performance Report and the Annual Review Mission. As the MDG
PF supports implementation of the HSDP IV, this Annual Review examines the
performance of the MDG PF as an instrument to achieve sector-wide progress
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