3,466 research outputs found

    GridNet with automatic shape prior registration for automatic MRI cardiac segmentation

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    In this paper, we propose a fully automatic MRI cardiac segmentation method based on a novel deep convolutional neural network (CNN) designed for the 2017 ACDC MICCAI challenge. The novelty of our network comes with its embedded shape prior and its loss function tailored to the cardiac anatomy. Our model includes a cardiac centerof-mass regression module which allows for an automatic shape prior registration. Also, since our method processes raw MR images without any manual preprocessing and/or image cropping, our CNN learns both high-level features (useful to distinguish the heart from other organs with a similar shape) and low-level features (useful to get accurate segmentation results). Those features are learned with a multi-resolution conv-deconv "grid" architecture which can be seen as an extension of the U-Net. Experimental results reveal that our method can segment the left and right ventricles as well as the myocardium from a 3D MRI cardiac volume in 0.4 second with an average Dice coefficient of 0.90 and an average Hausdorff distance of 10.4 mm.Comment: 8 pages, 1 tables, 2 figure

    Steps towards the development of a ‘culture of innovation’ amongst undergraduate industrial designers

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    Developing innovative solutions to problems is no easy task. Firstly there has to be a desire within the individual to seek out the innovative solution; secondly there is the problem of how to identify what constitutes an innovative solution; and finally one has to combat the natural tendency toward risk aversion. Successful industrial design is by its very nature innovative. Therefore generating a culture of innovation is a vital requirement in the development of a successful designer. Do we know how to stimulate, incubate and nurture innovation? What are the factors that give rise to an innovative mindset? This paper describes the experiences of an industrial design programme that for five years operated with a degree of success. However on review the programme was deemed to be lacking in innovation. Changes were made and after three years the impact was assessed and quantified and the results are now reported. Through the review strategies were developed which led to the creation of an environment for the promotion and nurturing of innovation appropriate to an undergraduate industrial design programme. Following the three year review further refinements to the model have been implemented, this will be the subject of further study

    SLAM visuel temps réel pour l'estimation précise de plan

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    National audienceCe papier présente un algorithme de localisation et cartographie simultanée (ou SLAM pour Simultaneous Localization And Mapping) utilisant des contraintes issues de modèles observés dans un environnement inconnu, on parle alors de SLAM contraint ou CSLAM . L'objectif est l'estimation précise des paramètres d'un objet présent dans la scène pour la réalité augmentée. Nous proposons pour cela d'inclure, dans une méthode d'ajustement de faisceaux incrémental, les paramètres de l'objet au même titre que les poses caméras et les points 3D nécessaires au CSLAM . Nous montrons, à travers l'exemple d'un modèle de plan 3D initialisé en ligne, que l'optimisation conjointe des paramètres permet, non seulement de contraindre les points 3D à se rapprocher du plan, mais également de contraindre le plan à se rapprocher des points 3D. Des expérimentations mettront en évidence la précision et le gain en temps de calcul de notre approche comparativement au CSLAM classique

    Gender, Age, and Frequency of Internet Use as Moderators of Citizens’ Adoption of Electronic Government

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    This paper proposes a model of citizen acceptance of e-government systems by extending UTAUT with two additional constructs (Anxiety and Attitude), and includes three moderators; gender, age, and frequency of Internet use. The model was tested with primary data gathered within the context of use of an e-government system in India. The model received good empirical support, explaining 53.7% of variance in citizen intention to make use of e-government systems. The paper contributes to e-government services research by highlighting key influencing factors (particularly the importance of attitude), identified a number of significant differences based on the use of the moderators, and identified a number of aspects appropriate for government attention and future work

    Study of transformations and microstructural modification in Ti-LCB and T-555 alloys using Differential Scanning Calorimetry

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    peer reviewedThe aerospace industry is the single largest market for titanium products primarily due to the exceptional strength to weight ratio, elevated temperature performance and corrosion resistance. Titanium applications are most significant in jet engine and airframe components that are subject to high temperatures. The studied Ti-LCB and Ti-555 titanium alloys must present good properties to fatigue damage as they are located in a low-pressure compressor. In order to avoid this damage, an optimized alloy microstructure is required. In our case, the optimal microstructure would be a beta matrix in which small alpha particles are uniformly distributed, obtained after a combination of thermomechanical and thermal treatments. The understanding of the mechanisms ruling the microstructure evolution is achieved through the study of phase transformations versus temperature. During heating, the ωath phase is transformed into the ωiso phase, allowing itself the appearance of the α phase. Then this α phase is transformed progressively into the β phase, and the structure becomes totally β when the transus temperature is reached. Therefore, a thermal analysis tool such as DSC (Differential Scanning Calorimetry) was used in order to characterise the phase transformations of the material during imposed controlled temperature programs

    1014-92 Impaired Microcirculation in Chronic Heart Failure

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    The microcirculation plays a crucial role in the exchange of oxygen, energy rich substrates and metabolites. The effects on the microcirculation of impaired heart function and disturbed peripheral skin circulation in chronic heart failure (CHF) are unknown. Nailfold capillary morphology and dynamics in CHF were studied in relation to parameters of left ventricular (LV) structure and function. Twenty patients (13 male, 7 female, age 64±2 years) with CHF NYHA class II underwent a capillaroscopic examination at the finger nailfold using a computerised videophotometric system (Capiflow) at rest and after 1 min arterial occlusion. Patients were treated with diuretics, ACE inhibitors and digoxin and mean duration of symptoms was 65±9 months. Study parameters were number, length, and diameter of the capillaries as well as capillary blood velocity (CBV). Further experiments included echocardiography and determination of LV ejection fraction by Tc-scintigraphy. Nailfold capillaries in established CHF are enlarged (afferent diameter 6.6±0.4 μm, efferent diameter 8.2±0.4 μm, ref. resp. <6 and <8 μm) and CBV is dramatically decreased (351±64 μ/s, ref. >600 μm/s at 23°C). The reactive hyperemic response to one minute arterial occlusion is attenuated (peak CBV 879±158 μm/s, ref >2000 μm/s). CBV correlates positively with LV ejection fraction (r=0.61, p=001) and inversely with LV end-diastolic (r=-0.56, P=0.04) and end-systolic (r=-0.69, P=0.01) diameters. The time-to-peak flow (35±5 s, ref. 6–10 s) after one min arterial occlusion is positively related (r=0.68, P<0.05) to the duration of CHF. Our data indicate that microcirculation in chronic heart failure deteriorates in function of the severity and duration of heart failure
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