4,592 research outputs found
Fast parallel volume visualization on cuda technology
In the medical diagnosis and treatment planning, radiologists and surgeons rely
heavily on the slices produced by medical imaging scanners. Unfortunately, most of
these scanners can only produce two dimensional images because the machines that
can produce three dimensional are very expensive. The two dimensional images from
these devices are difficult to interpret because they only show cross-sectional views
of the human structure. Consequently, such circumstances require highly qualified
doctors to use their expertise in the interpretation of the possible location, size or
shape of the abnormalities especially for large datasets of enormous amount of slices.
Previously, the concept of reconstructing two dimensional images to three
dimensional was introduced. However, such reconstruction model requires high
performance computation, may either be time-consuming or costly. Furthermore,
detecting the internal features of human anatomical structure, such as the imaging of
the blood vessels, is still an open topic in the computer-aided diagnosis of disorders
and pathologies. This study proposed, designed and implemented a visualization
framework named SurLens with high performance computing using Compute
Unified Device Architecture (CUDA), augmenting the widely proven ray casting
technique in terms of superior qualities of images but with slow speed. Considering
the rapid development of technology in the medical community, our framework is
implemented on Microsoft .NET environment for easy interoperability with other
emerging revolutionary tools. The Visualization System was evaluated with brain
datasets from the department of Surgery, University of North Carolina, United
States, containing 109 datasets of MRA, T1-FLASH, T2-Weighted, DTI and
T1-MPRAGE. Significantly, at a reasonably cheaper cost, SurLens Visualization
System achieves immediate reconstruction and obvious mappings of the internal
features of the human brain, reliable enough for instantaneously locate possible
blockages in the brain blood vessels without any prior segmentation of the datasets
International Cooperation to Resolve International Pollution Problems
This article provides a non-technical overview of important results of the game theoretical literature on the formation and stability of international environmental agreements (IEAs) on transboundary pollution control. It starts out by sketching features of first and second best solutions to the problem of transboundary pollution. It then argues that most actual IEAs can be considered at best as third best solutions. Therefore, three questions are raised: 1) Why is there a difference between actual IEAs and first and second best solutions? 2) Which factors determine this difference? 3) Which measures can help to narrow this difference? This article attempts to answer these questions after giving an informal introduction to coalition models.International pollution, International environmental agreements, Treaty design, Coalition theory
Using Ramsey theory to measure unavoidable spurious correlations in Big Data
Given a dataset we quantify how many patterns must always exist in the
dataset. Formally this is done through the lens of Ramsey theory of graphs, and
a quantitative bound known as Goodman's theorem. Combining statistical tools
with Ramsey theory of graphs gives a nuanced understanding of how far away a
dataset is from random, and what qualifies as a meaningful pattern.
This method is applied to a dataset of repeated voters in the 1984 US
congress, to quantify how homogeneous a subset of congressional voters is. We
also measure how transitive a subset of voters is. Statistical Ramsey theory is
also used with global economic trading data to provide evidence that global
markets are quite transitive.Comment: 21 page
Interacting Dark Energy and the Cosmic Coincidence Problem
The introduction of an interaction for dark energy to the standard cosmology
offers a potential solution to the cosmic coincidence problem. We examine the
conditions on the dark energy density that must be satisfied for this scenario
to be realized. Under some general conditions we find a stable attractor for
the evolution of the Universe in the future. Holographic conjectures for the
dark energy offer some specific examples of models with the desired properties.Comment: 8 pages, 3 figures, Phys. Rev. D versio
Pycnomerus thrinax : a new North America zopherid (Coleoptera)
Pycnomerus thrinax Ivie and Slipinski NEW SPECIES is described from the Florida Keys (USA), where it is found in rotting stems of the thatch palm, Thrinax paruiflora Sw. Illustrations and modifications to existing keys are provided
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