48,331 research outputs found
Space shuttle main engine: Interactive design challenges
The operating requirements established by NASA for the SSME were considerably more demanding than those for earlier rocket engines used in the military launch vehicles or Apollo program. The SSME, in order to achieve the high performance, low weight, long life, reusable objectives, embodied technical demands far in excess of its predecessor rocket engines. The requirements dictated the use of high combustion pressure and the staged combustion cycle which maximizes performance through total use of all propellants in the main combustion process. This approach presented a myriad of technical challenges for maximization of performance within attainable state of the art capabilities for operating pressures, operating temperatures and rotating machinery efficiencies. Controlling uniformity of the high pressure turbomachinery turbine temperature environment was a key challenge for thrust level and life capability demanding innovative engineering. New approaches in the design of the components were necessary to accommodate the multiple use, minimum maintenance objectives. Included were the use of line replaceable units to facilitate field maintenance automatic checkout and internal inspection capabilities
Interactive tag maps and tag clouds for the multiscale exploration of large spatio-temporal datasets
'Tag clouds' and 'tag maps' are introduced to represent geographically referenced text. In combination, these aspatial and spatial views are used to explore a large structured spatio-temporal data set by providing overviews and filtering by text and geography. Prototypes are implemented using freely available technologies including Google Earth and Yahoo! 's Tag Map applet. The interactive tag map and tag cloud techniques and the rapid prototyping method used are informally evaluated through successes and limitations encountered. Preliminary evaluation suggests that the techniques may be useful for generating insights when visualizing large data sets containing geo-referenced text strings. The rapid prototyping approach enabled the technique to be developed and evaluated, leading to geovisualization through which a number of ideas were generated. Limitations of this approach are reflected upon. Tag placement, generalisation and prominence at different scales are issues which have come to light in this study that warrant further work
Interactive visual exploration of a large spatio-temporal dataset: Reflections on a geovisualization mashup
Exploratory visual analysis is useful for the preliminary investigation of large structured, multifaceted spatio-temporal datasets. This process requires the selection and aggregation of records by time, space and attribute, the ability to transform data and the flexibility to apply appropriate visual encodings and interactions. We propose an approach inspired by geographical 'mashups' in which freely-available functionality and data are loosely but flexibly combined using de facto exchange standards. Our case study combines MySQL, PHP and the LandSerf GIS to allow Google Earth to be used for visual synthesis and interaction with encodings described in KML. This approach is applied to the exploration of a log of 1.42 million requests made of a mobile directory service. Novel combinations of interaction and visual encoding are developed including spatial 'tag clouds', 'tag maps', 'data dials' and multi-scale density surfaces. Four aspects of the approach are informally evaluated: the visual encodings employed, their success in the visual exploration of the clataset, the specific tools used and the 'rnashup' approach. Preliminary findings will be beneficial to others considering using mashups for visualization. The specific techniques developed may be more widely applied to offer insights into the structure of multifarious spatio-temporal data of the type explored here
Do changes in drinking motives mediate the relation between personality change and maturing out of problem drinking?
Recent research has indicated that developmental changes in the personality traits of neuroticism and impulsivity correlate with changes in problem drinking during emerging and young adulthood. However, it remains unclear what potential mechanisms, or mediators, could account for these associations. Drinking motives, particularly drinking to regulate negative affect (drinking to cope) and to get “high” or “drunk” (drinking for enhancement) have been posited to mediate the relationship between personality and drinking problems. Recent work indicates changes in drinking motives parallel changes in alcohol involvement from adolescence to young adulthood. The current study examined changes in drinking motives (i.e., coping and enhancement) as potential mediators of the relation between changes in personality (impulsivity and neuroticism) with changes in alcohol problems in emerging and young adulthood. Analyses were based on data collected from a cohort of college students (N=489) at varying risk for AUDs from ages 18–35. Parallel process latent growth modeling indicated that change in coping (but not enhancement) motives specifically mediated the relation between changes in neuroticism and alcohol problems as well as the relation between changes in impulsivity and alcohol problems. Findings suggest that change in coping motives is an important mechanism in the relation between personality change and the “maturing out” of problematic alcohol involvement
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Mashup cartography: cartographic issues of using Google Earth for tag maps
Resonant Scattering of Emission Lines in Coronal Loops: Effects on Image Morphology and Line Ratios
We have investigated the effects of resonant scattering of emission lines on
the image morphology and intensity from coronal loop structures. It has
previously been shown that line of sight effects in optically thin line
emission can yield loop images that appear uniformly bright at one viewing
angle, but show ``looptop sources'' at other viewing angles. For optically
thick loops where multiple resonant scattering is important, we use a 3D Monte
Carlo radiation transfer code. Our simulations show that the intensity
variation across the image is more uniform than the optically thin simulation
and, depending on viewing angle, the intensity may be lower or higher than that
predicted from optically thin simulations due to scattering out of or into the
line of sight.Comment: Accepted for publication in Ap
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Augmented paper applications: Initial user tests of a wireless pattern reader
A handheld pattern reader has been developed to read low visibility conductive patterns on paper. The patterns are formed by masking conductive paper with a non-conductive, printed lacquer. The reader was developed as part of an EU-funded project investigating methods of augmenting paper. Data read from the patterns was used to trigger events in the digital domain. Usability tests were undertaken to investigate the performance of the prototype. Results showed that at this stage of development there was significant variation in performance of the prototype from user to user. Further work is being undertaken to determine the causes of this variability
Quasi-isotropic spacecraft antenna system Final report
Spacecraft quasi-isotropic antenna system for space telemetr
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