We propose a new routing graph, the restricted Delaunay graph (RDG), for mobile ad hoc networks. Combined with a node clustering algorithm, the RDG can be used as an underlying graph for geographic routing protocols. ...
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We propose a new routing graph, the restricted Delaunay graph (RDG), for mobile ad hoc networks. Combined with a node clustering algorithm, the RDG can be used as an underlying graph for geographic routing protocols. This graph has the following attractive properties: 1) it is planar;2) between any two graph nodes there exists a path whose length, whether measured in terms of topological or Euclidean distance, is only a constant times the minimum length possible;and 3) the graph can be maintained efficiently in a distributed manner when the nodes move around. Furthermore, each node only needs constant time to make routing decisions. We show by simulation that the RDG outperforms previously proposed routing graphs in the context of the Greedy perimeter stateless routing (GPSR) protocol. Finally, we investigate theoretical bounds on the quality of paths discovered using GPSR.
We currently witness a massive digitization of domestic materials e.g. photos, music, calendars, recipes, notes, messages. This digitization provides new conditions for how we interact with materials as well as how us...
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Most medical image processing techniques require the clinician to form a mental model of the anatomy being depicted. We present systems that allow a more direct visualization of anatomical shapes and measurement of pa...
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Our aim is to produce a tessellation of space into small voxels and, based on only a few tomographic projections of an object, assign to each voxel a label that indicates one of the components of interest constituting...
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Our aim is to produce a tessellation of space into small voxels and, based on only a few tomographic projections of an object, assign to each voxel a label that indicates one of the components of interest constituting the object. Traditional methods are not reliable in applications, such as electron microscopy in which (due to the damage by radiation) only a few projections are available. We postulate a low level prior knowledge regarding the underlying distribution of label images, and then directly estimate the label image based on the prior and the projections. We use a relatively efficient approximation to a global search for the estimation.
Height fields and depth maps which we collectively refer to as z-fields, usually carry a lot of redundant information and are often used in real-time applications. This is the reason why efficient methods for their si...
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Height fields and depth maps which we collectively refer to as z-fields, usually carry a lot of redundant information and are often used in real-time applications. This is the reason why efficient methods for their simplification are necessary. On the other hand, the computation power and programmability of commodity graphics hardware has significantly grown. We present an adaptation of an existing real-time z-field simplification method for execution in graphics hardware. The main parts of the algorithm are implemented as fragment programs which run on the GPU. The resulting polygonal models are identical to the ones obtained by the original method. The main benefit is that the computation load is imposed on the GPU, freeing-up the CPU for other tasks. Additionally, the new method exhibits a performance improvement when compared to a pure CPU implementation.
Most medical image processing techniques require the clinician to form a mental model of the anatomy being depicted. We present systems that allow a more direct visualization of anatomical shapes and measurement of pa...
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ISBN:
(纸本)0780386396
Most medical image processing techniques require the clinician to form a mental model of the anatomy being depicted. We present systems that allow a more direct visualization of anatomical shapes and measurement of parameters from medical image data, including time-dependent and multi-modal image sets. Cardiac-Station realistically represents heart motion and extracts clinical parameters from ventricular MR images, in the diagnosis of heart disease. Brain-Reg displays abnormal regions of the brain by registering multi-modal images, and supports the analysis of differences in the hippocampus between patients and a control group.
Vector field visualization aims at generating images in order to convey the information existing in the data. We use Markov Random Field (MRF) texture synthesis methods to generate the visualization from a set of samp...
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Discrete tomography (DT) deals with the reconstruction of a function from its projections, when the function has a known discrete range. The knowledge of the discrete range, possibly together with some prior informati...
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Partitioning is a fundamental operation on graphs. In this paper we briefly review the basic concepts of graph partitioning and its relationship to digital mesh processing. We also elaborate on the connection between ...
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Partitioning is a fundamental operation on graphs. In this paper we briefly review the basic concepts of graph partitioning and its relationship to digital mesh processing. We also elaborate on the connection between graph partitioning and spectral graph theory. Applications in computergraphics are described.
We explore real time volume rendering of multichannel data for volumes with color and multimodal information. We demonstrate volume rendering of the visible human male color dataset and photorealistic rendering of vox...
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We explore real time volume rendering of multichannel data for volumes with color and multimodal information. We demonstrate volume rendering of the visible human male color dataset and photorealistic rendering of voxelized terrains, and achieve high quality visualizations. We render multimodal volumes utilizing hardware programmability for accumulation level mixing, and use CT and MRI information as examples. We also use multiboard parallel/distributed rendering schemes for large datasets and investigate scalability issues. We employ the VolumePro 1000 for real time multichannel volume rendering. Our approach, however, is not hardware-specific and can use commodity texture hardware instead.
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