600,837 research outputs found

    Serial automated quantitative CT analysis in idiopathic pulmonary fibrosis: functional correlations and comparison with changes in visual CT scores

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    OBJECTIVES: To determine whether computer-based CT quantitation of change can improve on visual change quantification of parenchymal features in IPF. METHODS: Sixty-six IPF patients with serial CT imaging (6-24 months apart) had CT features scored visually and with a computer software tool: ground glass opacity, reticulation and honeycombing (all three variables summed as interstitial lung disease extent [ILD]) and emphysema. Pulmonary vessel volume (PVV) was estimated by computer only. Relationships between changes in CT features and forced vital capacity (FVC) were examined using univariate and multivariate linear regression analyses. RESULTS: On univariate analysis, changes in computer variables demonstrated stronger linkages to FVC change than changes in visual scores (CALIPER ILD:R2=0.53, p<0.0001; Visual ILD:R2=0.16, p=0.001). PVV increase correlated most strongly with relative FVC change (R2=0.57). When PVV constituents (vessel size and location) were examined, an increase in middle zone vessels linked most strongly to FVC decline (R2=0.57) and was independent of baseline disease severity (characterised by CT fibrosis extent, FVC, or DLco). CONCLUSIONS: An increase in PVV, specifically an increase in middle zone lung vessels, was the strongest CT determinant of FVC decline in IPF and was independent of baseline disease severity. KEY POINTS: ‱ Computer analysis improves on visual CT scoring in evaluating deterioration on CT ‱ Increasing pulmonary vessel volume is the strongest CT predictor of functional deterioration ‱ Increasing pulmonary vessel volume predicts functional decline independent of baseline disease severity

    Quantification of chronic fibrosing interstitial pneumonia on computed tomography

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    The chronic fibrosing interstitial pneumonias (CFIPs) are diseases which cause progressive and often fatal progressive scarring of the lungs. The recent discovery of the first effective pharmacological therapies for this condition have increased interest in the monitoring of this disease. Due to the complex appearance of the CFIPs on computed tomography, visual quantification of disease severity and extent is limited. The purpose of this thesis was to develop and test a computer algorithm for the automated quantification of pulmonary fibrosis on CT using textural measures known as Minkowski functionals. A computer algorithm was successfully developed and this thesis presents initial results of testing the algorithm on a series of normal scans and on 24 prospectively recruited patients who also underwent a series of other tests including pulmonary function tests and a patient reported symptom questionnaire. The computer output was also compared with the visual assessment of two radiologists. Significant correlations were found between computer calculated lung volume and total lung capacity as measured on pulmonary function tests. We also found a significant correlation between computer calculated fibrosis volume and both gas transfer and forced vital capacity. The radiologists’ visual assessment of fibrosis and the computer estimated fibrosis volume were highly correlated. The novel computer algorithm represents a promising method for quantifying pulmonary fibrosis on CT with potential roles in monitoring disease progression and effects of therapeutic interventions

    Dimensions of web site credibility and their relation to active trust and behavioural impact

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    This paper discusses two trends that threaten to undermine the effectiveness of online social marketing interventions: growing mistrust and competition. As a solution, this paper examines the relationships between Web site credibility, target audiences’ active trust and behaviour. Using structural equation modelling to evaluate two credibility models, this study concludes that Web site credibility is best considered a three-dimensional construct composed of expertise, trustworthiness and visual appeal, and that trust plays a partial mediating role between Web site credibility and behavioural impacts. The paper examines theoretical implications of conceptualizing Web sites according to a human credibility model, and factoring trust into Internet-based behavioural change interventions. Practical guidelines suggest ways to address these findings when planning online social marketing interventions

    Recreating Daily life in Pompeii

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    [EN] We propose an integrated Mixed Reality methodology for recreating ancient daily life that features realistic simulations of animated virtual human actors (clothes, body, skin, face) who augment real environments and re-enact staged storytelling dramas. We aim to go further from traditional concepts of static cultural artifacts or rigid geometrical and 2D textual augmentations and allow for 3D, interactive, augmented historical character-based event representations in a mobile and wearable setup. This is the main contribution of the described work as well as the proposed extensions to AR Enabling technologies: a VR/AR character simulation kernel framework with real-time, clothed virtual humans that are dynamically superimposed on live camera input, animated and acting based on a predefined, historically correct scenario. We demonstrate such a real-time case study on the actual site of ancient Pompeii.The work presented has been supported by the Swiss Federal Office for Education and Science and the EU IST programme, in frame of the EU IST LIFEPLUS 34545 and EU ICT INTERMEDIA 38417 projects.Magnenat-Thalmann, N.; Papagiannakis, G. (2010). Recreating Daily life in Pompeii. Virtual Archaeology Review. 1(2):19-23. https://doi.org/10.4995/var.2010.4679OJS192312P. MILGRAM, F. KISHINO, (1994) "A Taxonomy of Mixed Reality Visual Displays", IEICE Trans. Information Systems, vol. E77-D, no. 12, pp. 1321-1329R. AZUMA, Y. BAILLOT, R. BEHRINGER, S. FEINER, S. JULIER, B. MACINTYRE, (2001) "Recent Advances in Augmented Reality", IEEE Computer Graphics and Applications, November/December http://dx.doi.org/10.1109/38.963459D. STRICKER, P. DÄHNE, F. SEIBERT, I. CHRISTOU, L. ALMEIDA, N. IOANNIDIS, (2001) "Design and Development Issues for ARCHEOGUIDE: An Augmented Reality-based Cultural Heritage On-site Guide", EuroImage ICAV 3D Conference in Augmented Virtual Environments and Three-dimensional Imaging, Mykonos, Greece, 30 May-01 JuneW. WOHLGEMUTH, G. TRIEBFÜRST, (2000)"ARVIKA: augmented reality for development, production and service", DARE 2000 on Designing augmented reality environments, Elsinore, Denmark http://dx.doi.org/10.1145/354666.354688H. TAMURA, H. YAMAMOTO, A. KATAYAMA, (2001) "Mixed reality: Future dreams seen at the border between real and virtual worlds", Computer Graphics and Applications, vol.21, no.6, pp.64-70 http://dx.doi.org/10.1109/38.963462M. PONDER, G. PAPAGIANNAKIS, T. MOLET, N. MAGNENAT-THALMANN, D. THALMANN, (2003) "VHD++ Development Framework: Towards Extendible, Component Based VR/AR Simulation Engine Featuring Advanced Virtual Character Technologies", IEEE Computer Society Press, CGI Proceedings, pp. 96-104 http://dx.doi.org/10.1109/cgi.2003.1214453Archaeological Superintendence of Pompeii (2009), http://www.pompeiisites.orgG. PAPAGIANNAKIS, S. SCHERTENLEIB, B. O'KENNEDY , M. POIZAT, N.MAGNENAT-THALMANN, A. STODDART, D.THALMANN, (2005) "Mixing Virtual and Real scenes in the site of ancient Pompeii",Journal of CAVW, p 11-24, Volume 16, Issue 1, John Wiley and Sons Ltd, FebruaryEGGES, A., PAPAGIANNAKIS, G., MAGNENAT-THALMANN, N., (2007) "Presence and Interaction in Mixed Reality", The Visual Computer, Springer-Verlag Volume 23, Number 5, MaySEO H., MAGNENAT-THALMANN N. (2003), An Automatic Modeling of Human Bodies from Sizing Parameters. In ACM SIGGRAPH, Symposium on Interactive 3D Graphics, pp19-26, pp234. http://dx.doi.org/10.1145/641480.641487VOLINO P., MAGNENAT-THALMANN N. (2006), Resolving Surface Collisions through Intersection Contour Minimization. In ACM Transactions on Graphics (Siggraph 2006 proceedings), 25(3), pp 1154-1159. http://dx.doi.org/10.1145/1179352.1142007http://dx.doi.org/10.1145/1141911.1142007PAPAGIANNAKIS, G., SINGH, G., MAGNENAT-THALMANN, N., (2008) "A survey of mobile and wireless technologies for augmented reality systems", Journal of Computer Animation and Virtual Worlds, John Wiley and Sons Ltd, 19, 1, pp. 3-22, February http://dx.doi.org/10.1002/cav.22

    Music Maker – A Camera-based Music Making Tool for Physical Rehabilitation

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    The therapeutic effects of playing music are being recognized increasingly in the field of rehabilitation medicine. People with physical disabilities, however, often do not have the motor dexterity needed to play an instrument. We developed a camera-based human-computer interface called "Music Maker" to provide such people with a means to make music by performing therapeutic exercises. Music Maker uses computer vision techniques to convert the movements of a patient's body part, for example, a finger, hand, or foot, into musical and visual feedback using the open software platform EyesWeb. It can be adjusted to a patient's particular therapeutic needs and provides quantitative tools for monitoring the recovery process and assessing therapeutic outcomes. We tested the potential of Music Maker as a rehabilitation tool with six subjects who responded to or created music in various movement exercises. In these proof-of-concept experiments, Music Maker has performed reliably and shown its promise as a therapeutic device.National Science Foundation (IIS-0308213, IIS-039009, IIS-0093367, P200A01031, EIA-0202067 to M.B.); National Institutes of Health (DC-03663 to E.S.); Boston University (Dudley Allen Sargent Research Fund (to A.L.)

    Inviwo -- A Visualization System with Usage Abstraction Levels

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    The complexity of today's visualization applications demands specific visualization systems tailored for the development of these applications. Frequently, such systems utilize levels of abstraction to improve the application development process, for instance by providing a data flow network editor. Unfortunately, these abstractions result in several issues, which need to be circumvented through an abstraction-centered system design. Often, a high level of abstraction hides low level details, which makes it difficult to directly access the underlying computing platform, which would be important to achieve an optimal performance. Therefore, we propose a layer structure developed for modern and sustainable visualization systems allowing developers to interact with all contained abstraction levels. We refer to this interaction capabilities as usage abstraction levels, since we target application developers with various levels of experience. We formulate the requirements for such a system, derive the desired architecture, and present how the concepts have been exemplary realized within the Inviwo visualization system. Furthermore, we address several specific challenges that arise during the realization of such a layered architecture, such as communication between different computing platforms, performance centered encapsulation, as well as layer-independent development by supporting cross layer documentation and debugging capabilities
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