SCIRun is a general purpose problem solving environment that seeks to integrate the steps of preparing, executing, and visualizing simulations of physical and biological systems. The implementation of SCIRun is by mea...
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SCIRun is a general purpose problem solving environment that seeks to integrate the steps of preparing, executing, and visualizing simulations of physical and biological systems. The implementation of SCIRun is by means of an interactive dataflow network consisting of modules and data pipes exposed as a visual programming language. SCIRun also contains specific modules for bioelectric field simulations and visualizations and the combination of SCIRun with this package is known as BioPSE (***/software/biopse). This software has been in the public domain since 2000 and in that time we have developed strategies for software development, engineering, testing, documentation, and training. We have also continued to expand the scope of the SCIRun/BioPSE package not only through our own codes but by constructing bridges to other systems, both open source and proprietary. We have also created a repository for relevant sample networks and datasets with the aim of allowing diverse groups to test and evaluate algorithms using identical data and to share their results with the community for comparison of performance and accuracy. We present here a summary of the software system and describe specific experiences and conclusions with regard to creating and managing a large open source software project carried out within a university setting.
Pressure-induced structural transformations in spherical and faceted gallium arsenide nanocrystals of various shapes and sizes are investigated with a parallel molecular-dynamics approach. The results show that the pr...
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Pressure-induced structural transformations in spherical and faceted gallium arsenide nanocrystals of various shapes and sizes are investigated with a parallel molecular-dynamics approach. The results show that the pressure for zinc blende to rocksalt structural transformation depends on the nanocrystal size, and all nanocrystals undergo nonuniform deformation during the transformation. Spherical nanocrystals above a critical diameter ≥44 Å transform with grain boundaries. Faceted nanocrystals of comparable size have grain boundaries in 60% of the cases, whereas the other 40% are free of grain boundaries. The structure of transformed nanocrystals shows that domain orientation and strain relative to the initial zinc blende lattice are not equivalent. These observations may have implications in interpreting the experimental x-ray line shapes from transformed nanocrystals.
We introduce the piecewise-linear Haar (PLHaar) transform, a reversible n-bit to n-bit transform that is based on the Haar wavelet transform. PLHaar is continuous, while all current n-bit to n-bit methods are not, and...
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We introduce the piecewise-linear Haar (PLHaar) transform, a reversible n-bit to n-bit transform that is based on the Haar wavelet transform. PLHaar is continuous, while all current n-bit to n-bit methods are not, and is therefore uniquely usable with both lossy and lossless methods (e.g. image compression). PLHaar has both integer and continuous (i.e. non-discrete) forms. By keeping the coefficients to n bits PLHaar is particularly suited for use in hardware environments where channel width is limited, such as digital video channels and graphics hardware.
The pressure-induced structural transformation in cadmium selenide is studied with the isothermal-isobaric molecular-dynamics method and electronic-structure calculations based on the density-functional theory. The re...
The pressure-induced structural transformation in cadmium selenide is studied with the isothermal-isobaric molecular-dynamics method and electronic-structure calculations based on the density-functional theory. The reversible transformation between the fourfold-coordinated wurtzite structure and the sixfold-coordinated rocksalt structure is successfully reproduced in the molecular-dynamics simulations, in which atomistic transition mechanisms including the existence of a metastable state as well as barrier states along the transition paths are observed. Accurate density-functional calculations confirm these transition paths. It is shown that there are at least three transition paths, which are characterized by atomic shifts in the (0001) plane of the wurtzite structure. The energy barrier for the transformation is found to be about 0.13eV∕pair and is almost independent of the paths.
We present novel algorithms for predictive tracking of user position and orientation based on double exponential smoothing. These algorithms, when compared against Kalman and extended Kalman filter-based predictors wi...
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We present a testbed for comparing predictive tracking algorithms that allows virtual environment system developers to make better choices about which predictors to use in their environments and aids researchers in de...
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The visually impaired have limited access to the world of mobile devices. Our goal was to design a handheld mobile device to overcome limitations such as reliance on visual display and lack of audio and tactile feedba...
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ISBN:
(纸本)1581136374
The visually impaired have limited access to the world of mobile devices. Our goal was to design a handheld mobile device to overcome limitations such as reliance on visual display and lack of audio and tactile feedback. We built a prototype handheld device using a combination of tactile feedback and auditory display based on preliminary research and testing. Our hypothesis was that this device would provide users with an interface with which they would be able to access advanced functions of a mobile device. This prototype was evaluated by both blind and sighted users. Based on both quantitative and qualitative measures, the results suggest that such a device can enhance the capabilities of visually impaired users of handheld mobile devices.
Computer science as a discipline is failing to reach a diverse audience. As a result, computational illiteracy threatens many groups of underserved students - women, minorities and possibly other, as yet undocumented ...
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Computer science as a discipline is failing to reach a diverse audience. As a result, computational illiteracy threatens many groups of underserved students - women, minorities and possibly other, as yet undocumented groups, such as students of the humanities. If learning programming were contextualized in domains relevant to different audiences, more students would be motivated to learn to program. I contend that teaching computer science in the context of digital media manipulation will attract and engage many students who would otherwise not choose to learn programming.
We present a testbed for comparing predictive tracking algorithms that allows virtual environment system developers to make better choices about which predictors to use in their environments and aids researchers in de...
ISBN:
(纸本)9781581136869
We present a testbed for comparing predictive tracking algorithms that allows virtual environment system developers to make better choices about which predictors to use in their environments and aids researchers in determining how predictors work across various virtual environment configurations. Our testbed saves the virtual environment developer and researcher both time and effort with the important task of reducing dynamic tracking error and masking latency. The testbed consists of three components: a prediction algorithm library, a motion data repository, and a graphical testing application which provides users with the ability to test different predictive tracking algorithms across a variety of user motion sequences. The testbed provides enough generality for testing across different algorithmic and system parameters such as sampling rate, prediction time, and noise variance. The paper describes the contents of the predictor library and how to extend it, the types of motion data sets collected thus far, the motion data preparation methodology, and the graphical testing application's functionality and architecture. A simple testing scenario showing output from the testbed is also presented.
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