132 research outputs found

    Impact of inflated structures on a liquid free surface.

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    International audienceThere are many situations where inflated structures may hit violently a liquid free surface. One of them occurs during sea-landing of helicopters. As a matter of fact helicopters are equipped with inflated floaters. Those floaters are made of impermeable tissues which are almost inextensible and their flexural rigidity is small. These mechanical characteristics are difficult to reproduce at model scales, that is why we found more conventional inflated balloons like space hopper. Experiments have been carried out in the flume of Ecole Centrale Marseille. Only qualitative measurements have been performed. High speed camera provided the main features of the phenomenona. This abtract sums up this experimental campaign and the first attempts done in the numerical modellings thus yielding some comparisons. It is shown that simple linearized models- both structural and hydrodynamic models - can reproduce the early stage of penetration when impact occurs

    Text lines and snippets extraction for 19th century handwriting documents<br /> layout analysis

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    International audienceIn this paper we propose a new approach to improve electronic editions of human science corpus, providing an efficient estimation of manuscripts pages structure. In any handwriting documents analysis process, the text line segmentation is an important stage. The presence of variable inter-line spaces, of inconstant base-line skews, overlapping and occlusions in unconstrained ancient 19th handwritten documents complexifies the text lines segmentation task. In this paper, we only use as prior knowledge of script the fact that text lines skews can be random and irregular. In that context, we model text line detection as an image segmentation problem by enhancing text line structure using Hough transform and a clustering of connected components so as to make text line boundaries appear. The proposed approach of snippets decomposition for page layout analysis lies on a first step of content pages classification in five visual and genetic taxonomies, and a second step of text line extraction and snippets decomposition. Experiments show that the proposed method achieves high accuracy for detecting text lines in regular and semi-regular handwritten pages in the corpus of digitized Flaubert manuscripts ("Dossiers documentaires de Bouvard et PĂ©cuchet", 1872-1880)

    Hierarchical decomposition of handwritten<br /> manuscripts layouts

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    http://www.springerlink.com/content/k6741wt1028l7310/International audienceIn this paper we propose a new approach to improve electronic editions of literary corpus, providing an efficient estimation of manuscripts pages structure. In any handwriting documents analysis process, structure recognition is an important issue. The presence of variable inter-line spaces, of inconstant base-line skews, overlappings and occlusions in unconstrained ancient 19th handwritten documents complicates the structure recognition task. Text line and fragment extraction is basedon the connexity labelling of the adjacency graph at different resolutionlevels, for borders, lines and fragments extraction

    Accuracy in predicting repetitions to task failure in resistance exercise: A scoping review and exploratory meta-analysis

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    BackgroundPrescribing repetitions relative to task failure is an emerging approach to resistance training. Under this approach, participants terminate the set based on their prediction of the remaining repetitions left to task failure. While this approach holds promise, an important step in its development is to determine how accurate participants are in their predictions. That is, what is the difference between the predicted and actual number of repetitions remaining to task failure, which ideally should be as small as possible.ObjectiveThe aim of this study was to examine the accuracy in predicting repetitions to task failure in resistance exercises.DesignScoping review and exploratory meta-analysis.Search and InclusionA systematic literature search was conducted in January 2021 using the PubMed, SPORTDiscus, and Google Scholar databases. Inclusion criteria included studies with healthy participants who predicted the number of repetitions they can complete to task failure in various resistance exercises, before or during an ongoing set, which was performed to task failure. Sixteen publications were eligible for inclusion, of which 13 publications covering 12 studies, with a total of 414 participants, were included in our meta-analysis.ResultsThe main multilevel meta-analysis model including all effects sizes (262 across 12 clusters) revealed that participants tended to underpredict the number of repetitions to task failure by 0.95 repetitions (95% confidence interval [CI] 0.17–1.73), but with considerable heterogeneity (Q(261) = 3060, p &lt; 0.0001, I2 = 97.9%). Meta-regressions showed that prediction accuracy slightly improved when the predictions were made closer to set failure (ÎČ =  − 0.025, 95% CI − 0.05 to 0.0014) and when the number of repetitions performed to task failure was lower (≀ 12 repetitions: ÎČ = 0.06, 95% CI 0.04–0.09; &gt; 12 repetitions: ÎČ = 0.47, 95% CI 0.44–0.49). Set number trivially influenced prediction accuracy with slightly increased accuracy in later sets (ÎČ =  − 0.07 repetitions, 95% CI − 0.14 to − 0.005). In contrast, participants’ training status did not seem to influence prediction accuracy (ÎČ =  − 0.006 repetitions, 95% CI − 0.02 to 0.007) and neither did the implementation of upper or lower body exercises (upper body – lower body =  − 0.58 repetitions; 95% CI − 2.32 to 1.16). Furthermore, there was minimal between-participant variation in predictive accuracy (standard deviation 1.45 repetitions, 95% CI 0.99–2.12).ConclusionsParticipants were imperfect in their ability to predict proximity to task failure independent of their training background. It remains to be determined whether the observed degree of inaccuracy should be considered acceptable. Despite this, prediction accuracies can be improved if they are provided closer to task failure, when using heavier loads, or in later sets. To reduce the heterogeneity between studies, future studies should include a clear and detailed account of how task failure was explained to participants and how it was confirmed

    Un modĂšle de Wagner gĂ©nĂ©ralisĂ©: Application Ă  l’impact de sections de formes arbitraires

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    International audienceA generalized Wagner method for studying water impact of arbitrary section is presented. This method does not require the deadrise angle to be small, unlike the classical linearized Wagner model. It can be applied to asymmetric sections by using conformal mapping. The problem is systematically transformed into an horizontal flat plate problem but it takes into account the exact geometry of the wetting surface. The flow around the flat plate is then calculated by using the theory of Riemann-Hilbert problems. The model is tested against both numerical and experimental results.Une mĂ©thode de Wagner gĂ©nĂ©ralisĂ©e pour l’étude de l’impact de sections de forme arbitraire est prĂ©sentĂ©e. Cette mĂ©thode permet de s’affranchir de l’hypothĂšse de faible angle mort sur laquelle reposent classiquement les mĂ©thodes de Wagner linĂ©arisĂ©es. Son domaine d’application s’étend Ă  des formes asymĂ©triques. Cela est rendu possible par la transformation systĂ©matique du problĂšme en celui d’un Ă©coulement autour d’une plaque plane horizontale, tout en tenant compte de la gĂ©omĂ©trie exacte de la surface mouillĂ©e. La thĂ©orie des problĂšmes de Riemann-Hilbert est utilisĂ©e pour rĂ©soudre le problĂšme transformĂ©. Les rĂ©sultats de ce modĂšle sont comparĂ©s Ă  d’autres rĂ©sultats numĂ©riques et expĂ©rimentaux

    European collaborative efforts to achieve effective, safe, and cost-controlled dismantling of nuclear facilities

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    This paper aims to give an overview of very recent European coordinate efforts to implement technologies of the “4.0 Industry” in the nuclear deconstruction sector. This objective aims to benefit from the lever of efficiency and reliability represented by innovative technologies on all the value chain of the dismantling, from early characterization to the dismantling operations themselves through engineering studies, waste management, project management and coordination of multiple stakeholders of each project. The outcomes of five projects (INNO4GRAPH, LD-SAFE, PLEIADES, CLEANDEM and INSIDER) are summarized here. They result in a unique data and knowledge common base, as well as in a significant sharing of experience based on dismantling projects already carried out or to come. They also result in designing new tools or methods natively taking into account the needs of a maximum of dismantling operators, as well as new test facilities. This will allow the undertaken joint work and collaboration to be continued. All of this paves the way to further collaborative projects and developments, in order to continue to implement reliable new technologies and processes in European dismantling projects to make future dismantling operations more efficient, safer and more cost-effective

    The Effects of Serotonin Receptor Antagonists on Contraction and Relaxation Responses Induced by Electrical Stimulation in the Rat Small Intestine

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    Background: The main source of 5-HT in body is in enterchromafin cells of intestine, different studies mentioned different roles for endogenous 5-HT and receptors involved and it is not clearified the mechanism of action of endogenous 5-HT. Objectives: To study the role of endogenous 5-HT on modulation of contraction and relaxation responses induced by electrical field stimulation (EFS) in different regions of the rat intestine. Materials and Methods: Segments taken from the rat duodenum, jejunum, mid and terminal ileum were vertically mounted, connected to a transducer and exposed to EFS with different frequencies in the absence and presence of various inhibitors of enteric mediators i. e. specific 5-HT receptor antagonists. Results: EFS-induced responses were sensitive to TTX and partly to atropine, indicating a major neuronal involvement and a cholinergic system. Pre-treatment with WAY100635 (a 5-HT1A receptor antagonist) and granisetron up to 10.0 ”M, GR113808 (a 5-HT4 receptor antagonist), methysergide and ritanserin up to 1.0 ”M, failed to modify responses to EFS inall examined tissues. In the presence of SB258585 1.0 ”M (a 5-HT6 receptor antagonist) there was a trend to enhance contraction in the proximal part of the intestine and reduce contraction in the distal part. Pre-treatment with SB269970A 1.0 ”M (5-HT7 receptor antagonist) induced a greater contractile response to EFS at 0.4 Hz only in the duodenum. Conclusions: The application of 5-HT1A, 5-HT2, 5-HT3, 5-HT4, 5-HT6 and 5-HT7 receptor antagonists, applied at concentrations lower than 1.0 ”M did not modify the EFS-induced contraction and relaxation responses, whichsuggests the unlikely involvement of endogenous 5-HT in mediating responses to EFS in the described test conditions. Keywords: Electric Stimulation Therapy; Serotonin 5-HT1 Receptor Antagonists; Intestine, Smal

    Transcribing a 17th-century botanical manuscript: Longitudinal evaluation of document layout detection and interactive transcription

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    [EN] We present a process for cost-effective transcription of cursive handwritten text images that has been tested on a 1,000-page 17th-century book about botanical species. The process comprised two main tasks, namely: (1) preprocessing: page layout analysis, text line detection, and extraction; and (2) transcription of the extracted text line images. Both tasks were carried out with semiautomatic pro- cedures, aimed at incrementally minimizing user correction effort, by means of computer-assisted line detection and interactive handwritten text recognition technologies. The contribution derived from this work is three-fold. First, we provide a detailed human-supervised transcription of a relatively large historical handwritten book, ready to be searchable, indexable, and accessible to cultural heritage scholars as well as the general public. Second, we have conducted the first longitudinal study to date on interactive handwriting text recognition, for which we provide a very comprehensive user assessment of the real-world per- formance of the technologies involved in this work. Third, as a result of this process, we have produced a detailed transcription and document layout infor- mation (i.e. high-quality labeled data) ready to be used by researchers working on automated technologies for document analysis and recognition.This work is supported by the European Commission through the EU projects HIMANIS (JPICH program, Spanish, grant Ref. PCIN-2015-068) and READ (Horizon-2020 program, grant Ref. 674943); and the Universitat Politecnica de Valencia (grant number SP20130189). This work was also part of the Valorization and I+D+i Resources program of VLC/CAMPUS and has been funded by the Spanish MECD as part of the International Excellence Campus program.Toselli, AH.; Leiva, LA.; Bordes-Cabrera, I.; Hernåndez-Tornero, C.; Bosch Campos, V.; Vidal, E. (2018). Transcribing a 17th-century botanical manuscript: Longitudinal evaluation of document layout detection and interactive transcription. Digital Scholarship in the Humanities. 33(1):173-202. https://doi.org/10.1093/llc/fqw064S173202331Bazzi, I., Schwartz, R., & Makhoul, J. (1999). An omnifont open-vocabulary OCR system for English and Arabic. IEEE Transactions on Pattern Analysis and Machine Intelligence, 21(6), 495-504. doi:10.1109/34.771314Causer, T., Tonra, J., & Wallace, V. (2012). Transcription maximized; expense minimized? Crowdsourcing and editing The Collected Works of Jeremy Bentham*. Literary and Linguistic Computing, 27(2), 119-137. doi:10.1093/llc/fqs004Ramel, J. Y., Leriche, S., Demonet, M. L., & Busson, S. (2007). User-driven page layout analysis of historical printed books. International Journal of Document Analysis and Recognition (IJDAR), 9(2-4), 243-261. doi:10.1007/s10032-007-0040-6Romero, V., Fornés, A., Serrano, N., Sånchez, J. A., Toselli, A. H., Frinken, V., 
 Lladós, J. (2013). The ESPOSALLES database: An ancient marriage license corpus for off-line handwriting recognition. Pattern Recognition, 46(6), 1658-1669. doi:10.1016/j.patcog.2012.11.024Romero, V., Toselli, A. H., & Vidal, E. (2012). Multimodal Interactive Handwritten Text Transcription. Series in Machine Perception and Artificial Intelligence. doi:10.1142/8394Toselli, A. H., Romero, V., Pastor, M., & Vidal, E. (2010). Multimodal interactive transcription of text images. Pattern Recognition, 43(5), 1814-1825. doi:10.1016/j.patcog.2009.11.019Toselli, A. H., Vidal, E., Romero, V., & Frinken, V. (2016). HMM word graph based keyword spotting in handwritten document images. Information Sciences, 370-371, 497-518. doi:10.1016/j.ins.2016.07.063Bunke, H., Bengio, S., & Vinciarelli, A. (2004). Offline recognition of unconstrained handwritten texts using HMMs and statistical language models. IEEE Transactions on Pattern Analysis and Machine Intelligence, 26(6), 709-720. doi:10.1109/tpami.2004.1

    Design and analysis of a Schwarz coupling method for a dimensionally heterogeneous problem

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    International audienceIn the present work, we study and analyze an efficient iterative coupling method for a dimensionally heterogeneous problem . We consider the case of 2-D Laplace equation with non symmetric boundary conditions with a corresponding 1-D Laplace equation. We will first show how to obtain the 1-D model from the 2-D one by integration along one direction, by analogy with the link between shallow water equations and the Navier-Stokes system. Then, we will focus on the design of an Schwarz-like iterative coupling method. We will discuss the choice of boundary conditions at coupling interfaces. We will prove the convergence of such algorithms and give some theoretical results related to the choice of the location of the coupling interface, and the control of the difference between a global 2-D reference solution and the 2-D coupled one. These theoretical results will be illustrated numerically.Dans ce document nous étudions et analysons et une méthode de couplage multidimensionnel itérative. Nous considérons le cas de l'équation de Laplace 2-D avec des conditions aux bords non symétriques, couplée avec une équation de Laplace 1-D correspondante. dans un premier temps nous montrons comment obtenir le modÚle 1-D à partir du modÚle 2-D par intégration verticale et par analogie avec la dérivation des équations de Saint-Venant à partir des équations de Navier-Stokes. Ensuite nous présentons un algorithme de couplage de type Schwarz. Nous discutons le choix des conditions aux interfaces de couplage. Nous démontrons la convergence de tels algorithmes et donnons quelques résultats théoriques sur le choix de la position des interfaces de couplage. Un résultat théorique sur le contrÎle de l'erreur entre la solution globale 2-D de référence et la solution 2-D couplée sera aussi donné. Enfin nous illustrons ces résultats numériquement
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