Littérature scientifique sur le sujet « Reconstruction par Patch »
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Articles de revues sur le sujet "Reconstruction par Patch"
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Rabii, R., F. Saint, L. Salomon, A. Hoznek, D. K. Chopin et C. C. Abbou. « La reconstruction artérielle par patch aortique détubulé dans la greffe simultanée rein–pancréas ». Annales d'Urologie 36, no 3 (2002) : 168–70. http://dx.doi.org/10.1016/s0003-4401(02)00094-3.
Texte intégral
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Park, Hyeseung, et Seungchul Park. « Improving Monocular Depth Estimation with Learned Perceptual Image Patch Similarity-Based Image Reconstruction and Left–Right Difference Image Constraints ». Electronics 12, no 17 (4 septembre 2023) : 3730. http://dx.doi.org/10.3390/electronics12173730.
Texte intégralRésumé :
This paper introduces a novel approach for self-supervised monocular depth estimation. The model is trained on stereo–image (left–right pair) data and incorporates carefully designed perceptual image quality assessment-based loss functions for image reconstruction and left–right image difference. The fidelity of the reconstructed images, obtained by warping the input images using the predicted disparity maps, significantly influences the accuracy of depth estimation in self-supervised monocular depth networks. The suggested LPIPS (Learned Perceptual Image Patch Similarity)-based evaluation of image reconstruction accurately emulates human perceptual mechanisms to quantify the quality of reconstructed images, serving as an image reconstruction loss. Consequently, it facilitates the gradual convergence of the reconstructed images toward a greater similarity with the target images during the training process. Stereo–image pair often exhibits slight discrepancies in brightness, contrast, color, and camera angle due to factors like lighting conditions and camera calibration inaccuracies. These factors limit the improvement of image reconstruction quality. To address this, the left–right difference image loss is introduced, aimed at aligning the disparities between the actual left–right image pair and the reconstructed left–right image pair. Due to the tendency of distant pixel values to approach zero in the difference images derived from the left and right source images of stereo pairs, this loss progressively steers the distant pixel values of the reconstructed difference images toward a convergence with zero. Hence, the use of this loss has demonstrated its efficacy in mitigating distortions in distant regions while enhancing overall performance. The primary objective of this study is to introduce and validate the effectiveness of LPIPS-based image reconstruction and left–right difference image losses in the context of monocular depth estimation. To this end, the proposed loss functions have been seamlessly integrated into a straightforward single-task stereo–image learning framework, incorporating simple hyperparameters. Notably, our approach achieves superior results compared to other state-of-the-art methods, even those adopting more intricate hybrid data and multi-task learning strategies.
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Tarchouli, Marwa, Marc Riviere, Thomas Guionnet, Wassim Hamidouche, Meriem Outtas et Olivier Deforges. « Patch-Based Image Learned Codec using Overlapping ». Signal & ; Image Processing : An International Journal 14, no 1 (27 février 2023) : 1–21. http://dx.doi.org/10.5121/sipij.2023.14101.
Texte intégralRésumé :
End-to-end learned image and video codecs, based on auto-encoder architecture, adapt naturally to image resolution, thanks to their convolutional aspect. However, while coding high resolution images, these codecs face hardware problems such as memory saturation. This paper proposes a patch-based image coding solution based on an end-to-end learned model, which aims to remedy to the hardware limitation while maintaining the same quality as full resolution image coding. Our method consists in coding overlapping patches of the image and reconstructing them into a decoded image using a weighting function. This approach manages to be on par with the performance of full resolution image coding using an endto-end learned model, and even slightly outperforms it, while being adaptable to different memory sizes. Moreover, this work undertakes a full study on the effect of the patch size on this solution’s performance, and consequently determines the best patch resolution in terms of coding time and coding efficiency. Finally, the method introduced in this work is also compatible with any learned codec based on a conv/deconvolutional autoencoder architecture without having to retrain the model.
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Wilén, Nina. « Entre souveraineté copartagée et coopération conditionnelle ». Études internationales 42, no 2 (13 septembre 2011) : 159–77. http://dx.doi.org/10.7202/1005824ar.
Texte intégralRésumé :
Cet article souhaite examiner la reconstruction de l'État du Liberia par les acteurs externes et propose d'analyser en particulier le Programme d'assistance à la gouvernance et à la gestion de l'économie (GEMAP). Ce programme repose sur des cosignatures par des experts internationaux pour des dépenses étatiques. L'argument soutenu ici est que le Liberia se trouve dans une situation paradoxale, à mi-chemin entre une coopération conditionnelle et une cosouveraineté avec ses partenaires internationaux qui n'est ni volontaire, ni clairement imposée. Pour comprendre ce phénomène, l'auteure adopte un cadre théorique basé sur la path dependency . Cet article étudie donc le fondement et le fonctionnement du GEMAP afi n d'illustrer ce propos.
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Dandi, Yatin, Homanga Bharadhwaj, Abhishek Kumar et Piyush Rai. « Generalized Adversarially Learned Inference ». Proceedings of the AAAI Conference on Artificial Intelligence 35, no 8 (18 mai 2021) : 7185–92. http://dx.doi.org/10.1609/aaai.v35i8.16883.
Texte intégralRésumé :
Allowing effective inference of latent vectors while training GANs can greatly increase their applicability in various downstream tasks. Recent approaches, such as ALI and BiGAN frameworks, develop methods of inference of latent variables in GANs by adversarially training an image generator along with an encoder to match two joint distributions of image and latent vector pairs. We generalize these approaches to incorporate multiple layers of feedback on reconstructions, self-supervision, and other forms of supervision based on prior or learned knowledge about the desired solutions. We achieve this by modifying the discriminator's objective to correctly identify more than two joint distributions of tuples of an arbitrary number of random variables consisting of images, latent vectors, and other variables generated through auxiliary tasks, such as reconstruction and inpainting or as outputs of suitable pre-trained models. We design a non-saturating maximization objective for the generator-encoder pair and prove that the resulting adversarial game corresponds to a global optimum that simultaneously matches all the distributions. Within our proposed framework, we introduce a novel set of techniques for providing self-supervised feedback to the model based on properties, such as patch-level correspondence and cycle consistency of reconstructions. Through comprehensive experiments, we demonstrate the efficacy, scalability, and flexibility of the proposed approach for a variety of tasks. The appendix of the paper can be found at the following link: https://drive.google.com/file/d/1i99e682CqYWMEDXlnqkqrctGLVA9viiz/view?usp=sharing
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Kwok, Ka Hei Martin, Matti Kortelainen, Giuseppe Cerati, Alexei Strelchenko, Oliver Gutsche, Allison Reinsvold Hall, Steve Lantz et al. « Application of performance portability solutions for GPUs and many-core CPUs to track reconstruction kernels ». EPJ Web of Conferences 295 (2024) : 11003. http://dx.doi.org/10.1051/epjconf/202429511003.
Texte intégralRésumé :
Next generation High-Energy Physics (HEP) experiments are presented with significant computational challenges, both in terms of data volume and processing power. Using compute accelerators, such as GPUs, is one of the promising ways to provide the necessary computational power to meet the challenge. The current programming models for compute accelerators often involve using architecture-specific programming languages promoted by the hardware vendors and hence limit the set of platforms that the code can run on. Developing software with platform restrictions is especially unfeasible for HEP communities as it takes significant effort to convert typical HEP algorithms into ones that are efficient for compute accelerators. Multiple performance portability solutions have recently emerged and provide an alternative path for using compute accelerators, which allow the code to be executed on hardware from different vendors. We apply several portability solutions, such as Kokkos, SYCL, C++17 std::execution::par, Alpaka, and OpenMP/OpenACC, on two mini-apps extracted from the mkFit project: p2z and p2r. These apps include basic kernels for a Kalman filter track fit, such as propagation and update of track parameters, for detectors at a fixed z or fixed r position, respectively. The two mini-apps explore different memory layout formats. We report on the development experience with different portability solutions, as well as their performance on GPUs and many-core CPUs, measured as the throughput of the kernels from different GPU and CPU vendors such as NVIDIA, AMD and Intel.
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MacKenzie, Hector M. « The Path to Temptation : The Negotiation of Canada’s Reconstruction Loan to Britain in 1946 ». Historical Papers 17, no 1 (26 avril 2006) : 196–220. http://dx.doi.org/10.7202/030891ar.
Texte intégralRésumé :
Résumé Pendant la Deuxième Guerre Mondiale, la dépendance économique du Canada vis-à-vis du commerce international augmenta considérablement. En 1944, en effet, les exportations canadiennes comptaient pour 31 pour cent du revenu national. La bonne part de ces exportations, toutefois, était dirigée vers le Royaume-Uni et était surtout constituée des contributions canadiennes à ce qu'il était convenu d'appeler, à l'époque, l'effort de guerre. Conséquemment, tout au long des années de guerre, le marché britannique exerça une influence certaine, voire souvent décisive, sur les politiques économiques extérieures du Canada. On comprend, dès lors, que le Canada ait surveillé de près les politiques commerciales de Whitehall, préoccupé qu'il était des problèmes que poserait le financement des échanges commerciaux entre les pays pendant la période de transition entre la guerre et la paix et de la nécessité qu'il y avait de s'assurer un marché stable et prospère dans le futur. L'auteur étudie ici une des ententes qui résulta de ces préoccupations, soit celle d'un prêt consenti par le Canada au Royaume-Uni, en 1946, en vue de sa reconstruction. En replaçant toute la question dans le contexte des intérêts économiques et politiques du gouvernement canadien de l'époque, l'auteur examine l'arrière-plan de la démarche et retrace minutieusement les diverses négociations qui aboutirent à l'entente finale.
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Gapon, Nikolay, Roman Sizyakin, Marina Zhdanova, Oksana Balabaeva et Yigang Cen. « Modified Depth-Map Inpainting Method Using the Neural Network ». EPJ Web of Conferences 224 (2019) : 04005. http://dx.doi.org/10.1051/epjconf/201922404005.
Texte intégralRésumé :
This paper proposes a method for reconstructing a depth map obtained using a stereo pair image. The proposed approach is based on a geometric model for the synthesis of patches. The entire image is preliminarily divided into blocks of different size, where large blocks are used to restore homogeneous areas, and small blocks are used to restore details of the image structure. Lost pixels are recovered by copying the pixel values from the source based on the similarity criterion. We used a trained neural network to select the “best like” patch. Experimental results show that the proposed method gives better results than other modern methods, both in subjective and objective measurements for reconstructing a depth map.
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Mehedi, Ibrahim M., K. Prahlad Rao, Ubaid M. Al-Saggaf, Hadi Mohsen Alkanfery, Maamar Bettayeb et Rahtul Jannat. « Intelligent Tomographic Microwave Imaging for Breast Tumor Localization ». Mathematical Problems in Engineering 2022 (25 mai 2022) : 1–9. http://dx.doi.org/10.1155/2022/4090351.
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Researchers are continuously exploring the potential use of microwave imaging in the early detection of breast cancer. The technique offers a promising alternative to mammography, a standard clinical imaging procedure today. The contrast in dielectric properties between normal and cancerous tissues makes microwave imaging a viable technique for detecting breast cancer. Experimental results are presented in this paper that demonstrate the detection of breast cancer using microwaves operating at 2.4 GHz. The procedure involves antenna fabrication, phantom tissue development, and image reconstruction. Design and fabrication of patch antenna are used in the study, described in detail. The patch antenna pair is used for transmitting and receiving source waves. Tissue mimicking models were developed from paraffin wax and glycerin for the dielectric constants of 9 and 47, respectively, representing the tissue and tumor. Further, AI-based tomographic images were obtained by implementing a filtered back-projection algorithm in the computer. In the results, the presence of the tumor is quantitatively analyzed.
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Stathopoulou, E. K., et F. Remondino. « MULTI-VIEW STEREO WITH SEMANTIC PRIORS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W15 (26 août 2019) : 1135–40. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w15-1135-2019.
Texte intégralRésumé :
<p><strong>Abstract.</strong> Patch-based stereo is nowadays a commonly used image-based technique for dense 3D reconstruction in large scale multi-view applications. The typical steps of such a pipeline can be summarized in stereo pair selection, depth map computation, depth map refinement and, finally, fusion in order to generate a complete and accurate representation of the scene in 3D. In this study, we aim to support the standard dense 3D reconstruction of scenes as implemented in the open source library OpenMVS by using semantic priors. To this end, during the depth map fusion step, along with the depth consistency check between depth maps of neighbouring views referring to the same part of the 3D scene, we impose extra semantic constraints in order to remove possible errors and selectively obtain segmented point clouds per label, boosting automation towards this direction. In order to reassure semantic coherence between neighbouring views, additional semantic criterions can be considered, aiming to eliminate mismatches of pixels belonging in different classes.</p>
Thèses sur le sujet "Reconstruction par Patch"
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Pinton, Noel Jeffrey. « Reconstruction synergique TEP/TDM à l'aide de l'apprentissage profond ». Electronic Thesis or Diss., Brest, 2024. http://www.theses.fr/2024BRES0123.
Texte intégralRésumé :
L’adoption généralisée des scanners hybrides Tomographie à émission de positons (TEP)/Tomodensitométrie (TDM) a conduit à une augmentation significative de la disponibilité des données d’imagerie combinées TEP/TDM. Cependant, les méthodologies actuelles traitent souvent chaque modalité de manière indépendante, négligeant ainsi le potentiel d’amélioration de la qualité des images grâce à l’exploitation des informations anatomiques et fonctionnelles complémentaires propres à chaque modalité. Exploiter ces informations intermodales pourrait améliorer les reconstructions TEP et TDM en fournissant une vision synergique des détails anatomiques et fonctionnels. Cette thèse propose une méthode innovante de reconstruction synergique d’images médicales via des modèles génératifs multibranches. En exploitant des autoencodeurs variationnels (VAE) multi-branches, notre approche apprend conjointement des images TEP et TDM, assurant un débruitage efficace et une reconstruction haute-fidélité. Ce cadre améliore la qualité des images et ouvre de nouvelles perspectives pour l’imagerie médicale multimodale en contexte clinique et de rechercheThe widespread adoption of hybrid Positron emission tomography (PET)/Computed tomography (CT) scanners has led to a significant increase in the availability of combined PET/CT imaging data. However, current methodologies often process each modality independently, overlooking the potential to enhance image quality by leveraging the complementary anatomical and functional information intrinsic to each modality. Exploiting intermodal information has the potential to improve both PET and CT reconstructions by providing a synergistic view of anatomical and functional details. This thesis introduces a novel approach for synergistic reconstruction of medical images using multi-branch generative models. By employing variational autoencoders (VAEs) with a multi-branch architecture, our model simultaneously learns from paired PET and CT images,allowing for effective joint denoising and highfidelity reconstruction of both modalities. Beyond improving image quality, this framework also paves the way for future advancements in multi-modal medical imaging, highlighting the transformative potential of integrated approaches for hybrid imaging modalities in clinical and research settings
2
Rambour, Clément. « Approches tomographiques structurelles pour l'analyse du milieu urbain par tomographie SAR THR : TomoSAR ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT007/document.
Texte intégralRésumé :
La tomographie SAR exploite plusieurs acquisitions d'une même zone acquises d'un point de vue légerement différent pour reconstruire la densité complexe de réflectivité au sol. Cette technique d'imagerie s'appuyant sur l'émission et la réception d'ondes électromagnétiques cohérentes, les données analysées sont complexes et l'information spatiale manquante (selon la verticale) est codée dans la phase. De nombreuse méthodes ont pu être proposées pour retrouver cette information. L'utilisation des redondances naturelles à certains milieux n'est toutefois généralement pas exploitée pour améliorer l'estimation tomographique. Cette thèse propose d'utiliser l'information structurelle propre aux structures urbaines pour régulariser les densités de réflecteurs obtenues par cette techniqueSAR tomography consists in exploiting multiple images from the same area acquired from a slightly different angle to retrieve the 3-D distribution of the complex reflectivity on the ground. As the transmitted waves are coherent, the desired spatial information (along with the vertical axis) is coded in the phase of the pixels. Many methods have been proposed to retrieve this information in the past years. However, the natural redundancies of the scene are generally not exploited to improve the tomographic estimation step. This Ph.D. presents new approaches to regularize the estimated reflectivity density obtained through SAR tomography by exploiting the urban geometrical structures
3
Rambour, Clément. « Approches tomographiques structurelles pour l'analyse du milieu urbain par tomographie SAR THR : TomoSAR ». Electronic Thesis or Diss., Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT007.
Texte intégralRésumé :
La tomographie SAR exploite plusieurs acquisitions d'une même zone acquises d'un point de vue légerement différent pour reconstruire la densité complexe de réflectivité au sol. Cette technique d'imagerie s'appuyant sur l'émission et la réception d'ondes électromagnétiques cohérentes, les données analysées sont complexes et l'information spatiale manquante (selon la verticale) est codée dans la phase. De nombreuse méthodes ont pu être proposées pour retrouver cette information. L'utilisation des redondances naturelles à certains milieux n'est toutefois généralement pas exploitée pour améliorer l'estimation tomographique. Cette thèse propose d'utiliser l'information structurelle propre aux structures urbaines pour régulariser les densités de réflecteurs obtenues par cette techniqueSAR tomography consists in exploiting multiple images from the same area acquired from a slightly different angle to retrieve the 3-D distribution of the complex reflectivity on the ground. As the transmitted waves are coherent, the desired spatial information (along with the vertical axis) is coded in the phase of the pixels. Many methods have been proposed to retrieve this information in the past years. However, the natural redundancies of the scene are generally not exploited to improve the tomographic estimation step. This Ph.D. presents new approaches to regularize the estimated reflectivity density obtained through SAR tomography by exploiting the urban geometrical structures
4
Song, Xin. « Path reconstruction in diffusion tensor magnetic resonance imaging ». Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00694403.
Texte intégralRésumé :
The complicated underwater environment and the poor underwater vision make super-mini underwater cable robot hardly to be controlled. Traditionally, the manual control method by operators is adopted by this kind of robots. Unfortunately, the robots can hardly work normally in these practical circumstances. Therefore, to overcome these shortcomings and improve the abilities of these underwater cable robots, this paper proposes several improvements, including the system design, the motion controller design, three dimensional obstacle recognition and three dimensional path reconstruction technologies etc. The details are displayed as follow: (1) Super-mini underwater robot system design: several improvement schemes and important design ideas are investigated for the super-mini underwater robot.(2) Super-mini robot motion controller design: The motion controller design of underwater robot in complicated circumstance is investigated. A new adaptive neural network sliding mode controller with balanced parameter controller (ANNSMB) is proposed. Based on the theory of adaptive fuzzy sliding mode controller (AFSMC), an improved algorithm is also proposed and applied to the underwater robot. (3)Research of three dimensional underwater environment reconstructions: The algorithms and the experiments of underwater environment reconstructions are investigated. DT-MRI image processing algorithm and the theory of three dimensional obstacle reconstructions are adopted and improved for the application of the underwater robot. (4) The super-mini underwater robot path planning algorithms are investigated.
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Claireau, Fabien. « Evaluation des impacts de la fragmentation du paysage par une autoroute sur les chauves-souris à différentes échelles spatio-temporelles ». Thesis, Paris, Muséum national d'histoire naturelle, 2018. http://www.theses.fr/2018MNHN0018/document.
Texte intégralRésumé :
Les infrastructures linéaires de transports (ILT), dont les routes, sont une des principales causes du déclin de la biodiversité. Bien que les évaluations environnementales permettent de limiter ce déclin, la séquence "Eviter, Réduire et Compenser" les impacts peine à s'appliquer pleinement. En effet, la séquence ERC fait bien souvent appel à des données qualitatives en oubliant les processus biologiques et/ou écologiques et leur échelle spatio-temporelle. L'impact des routes est globalement bien documenté pour plusieurs groupes biologiques, hormis pour les chauves-souris, pourtant susceptibles d'être très fortement affectées. Par ailleurs, leur protection stricte nécessite leur prise en compte dans la séquence ERC. Pour étudier l’impact des routes, et notamment des autoroutes, je me suis concentré sur l’étude des chauves-souris afin de mesurer et quantifier leur magnitude. Pour cela, différentes méthodes développées et réutilisables par les différents acteurs de terrain seront présentées. Ainsi, dans un premier temps, je me suis intéressé à une méthode de traitement des données issues d'écoutes acoustiques et à une méthode de valorisation. Dans un second temps, nous avons appliqué ces méthodes afin (i) de connaitre quels étaient les impacts des routes sur les populations de chauves-souris et (ii) afin d'évaluer l'efficience des mesures de réductions engagées pour réduire ces impacts. Nos principaux résultats montrent que les autoroutes ont un impact négatif significatif sur l'activité de chasse et de transit pour plusieurs espèces de chauves-souris jusqu'à au moins cinq kilomètres de distance à une autoroute. De plus, l'effet des autoroutes semblerait également avoir des conséquences sur la génétique des populations. Enfin, nous avons étudié les chiroptéroducs, ouvrages dédiés aux chauves-souris visant à réduire ces impacts par l'amélioration des connectivités écologiques. Ce type d'ouvrage dédié semble être approprié lorsqu'il est situé dans des corridors écologiques fins tels que les haiesBiodiversity is being lost at an increased rate as a result of human activities. One of the major threats to biodiversity is infrastructural development. Although the measures taken in environmental impact assessments can limit this loss, the mitigation hierarchy to "Avoid, Reduce and Offset" impacts on biodiversity is not fully functional. Indeed, the mitigation hierarchy often uses qualitative data and does not account for the biological and/or ecological processes and their different spatial and temporal scales. The impact of roads is well documented for several biological groups but not for bats whereas they are likely to be very strongly affected. Moreover, as they are strictly protected, they should be considered in the mitigation hierarchy. Therefore, through the study of bats, I investigated the effects of roads, especially major roads, and intended to measure and quantify the magnitude of their impacts. This thesis presents different methods developed to reach this objective and which may be used by stakeholders in the field. First, I intended to determine how to process data collected through passive acoustic monitoring and how to exploit these data. Then I determined what the impacts of roads on bat populations are and I proposed a method in order to assess the mitigation measures which presume to restore bat habitat connectivity. Our main results show a significant negative effect of roads on bats foraging and commuting behaviour for several species and up to at least five kilometres away from a major road. In addition, the effect of major roads also seems to have consequences on populations’ genetics. Finally, we studied bat overpasses which are structures specifically dedicated to bats and aiming at reducing the impacts of roads by improving bats’ habitat connectivity. These structures seem to be appropriate when located in narrow ecological corridors such as hedgerows
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Claireau, Fabien. « Evaluation des impacts de la fragmentation du paysage par une autoroute sur les chauves-souris à différentes échelles spatio-temporelles ». Electronic Thesis or Diss., Paris, Muséum national d'histoire naturelle, 2018. http://www.theses.fr/2018MNHN0018.
Texte intégralRésumé :
Les infrastructures linéaires de transports (ILT), dont les routes, sont une des principales causes du déclin de la biodiversité. Bien que les évaluations environnementales permettent de limiter ce déclin, la séquence "Eviter, Réduire et Compenser" les impacts peine à s'appliquer pleinement. En effet, la séquence ERC fait bien souvent appel à des données qualitatives en oubliant les processus biologiques et/ou écologiques et leur échelle spatio-temporelle. L'impact des routes est globalement bien documenté pour plusieurs groupes biologiques, hormis pour les chauves-souris, pourtant susceptibles d'être très fortement affectées. Par ailleurs, leur protection stricte nécessite leur prise en compte dans la séquence ERC. Pour étudier l’impact des routes, et notamment des autoroutes, je me suis concentré sur l’étude des chauves-souris afin de mesurer et quantifier leur magnitude. Pour cela, différentes méthodes développées et réutilisables par les différents acteurs de terrain seront présentées. Ainsi, dans un premier temps, je me suis intéressé à une méthode de traitement des données issues d'écoutes acoustiques et à une méthode de valorisation. Dans un second temps, nous avons appliqué ces méthodes afin (i) de connaitre quels étaient les impacts des routes sur les populations de chauves-souris et (ii) afin d'évaluer l'efficience des mesures de réductions engagées pour réduire ces impacts. Nos principaux résultats montrent que les autoroutes ont un impact négatif significatif sur l'activité de chasse et de transit pour plusieurs espèces de chauves-souris jusqu'à au moins cinq kilomètres de distance à une autoroute. De plus, l'effet des autoroutes semblerait également avoir des conséquences sur la génétique des populations. Enfin, nous avons étudié les chiroptéroducs, ouvrages dédiés aux chauves-souris visant à réduire ces impacts par l'amélioration des connectivités écologiques. Ce type d'ouvrage dédié semble être approprié lorsqu'il est situé dans des corridors écologiques fins tels que les haiesBiodiversity is being lost at an increased rate as a result of human activities. One of the major threats to biodiversity is infrastructural development. Although the measures taken in environmental impact assessments can limit this loss, the mitigation hierarchy to "Avoid, Reduce and Offset" impacts on biodiversity is not fully functional. Indeed, the mitigation hierarchy often uses qualitative data and does not account for the biological and/or ecological processes and their different spatial and temporal scales. The impact of roads is well documented for several biological groups but not for bats whereas they are likely to be very strongly affected. Moreover, as they are strictly protected, they should be considered in the mitigation hierarchy. Therefore, through the study of bats, I investigated the effects of roads, especially major roads, and intended to measure and quantify the magnitude of their impacts. This thesis presents different methods developed to reach this objective and which may be used by stakeholders in the field. First, I intended to determine how to process data collected through passive acoustic monitoring and how to exploit these data. Then I determined what the impacts of roads on bat populations are and I proposed a method in order to assess the mitigation measures which presume to restore bat habitat connectivity. Our main results show a significant negative effect of roads on bats foraging and commuting behaviour for several species and up to at least five kilometres away from a major road. In addition, the effect of major roads also seems to have consequences on populations’ genetics. Finally, we studied bat overpasses which are structures specifically dedicated to bats and aiming at reducing the impacts of roads by improving bats’ habitat connectivity. These structures seem to be appropriate when located in narrow ecological corridors such as hedgerows
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Ding, Yanzheng. « Une analyse d’images pour l'identification microstructurale en 3D d’un kaolin saturé sous chargement mécanique ». Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0051.
Texte intégralRésumé :
L'étude de la microstructure des argiles remaniées et saturées est cruciale pour la compréhension de leur comportement mécanique et des mécanismes de déformations volumiques. Cette thèse vise à identifier en 3D les mécanismes locaux qui s'activent au niveau de la microstructure en lien avec le chargement mécanique des milieux argileux. D'abord le comportement mécanique du Kaolin K13 est étudié à l'échelle de l'éprouvette sur deux chemins de chargement : œdométrique et isotrope. Ensuite, un protocole d'observation a été mis en place pour l'acquisition des images tridimensionnelles en utilisant la microscopie électronique à balayage (MEB) couplée à la Sonde Ionique Focalisée (FIB). La reconstitution des images obtenues par FIB-MEB nous permet d'accéder à la géométrie 3D d'un sous volume de l'échantillon. La deuxième partie consiste à développer une approche d'analyse quantitative en 3D permettant d'identifier les propriétés de la microstructure sur les différents chemins de chargement étudiés. La morphologie des pores est étudiée en utilisant les paramètres : flatness, élongation et sphéricité. L'orientation des pores et des particules a été d'abord identifier sur des images 2D représentants des coupes dans l'échantillon et étendue au 3D sur l'ensemble du volume et ceci sur les deux chemins de chargement. Les résultats obtenus dans le cadre de ce travail de thèse ont permis de mettre en évidence l'apport des images 3D à la compréhension de la microstructure des argiles remaniées saturéesAbstractMicrostructure investigation is essential for a better understanding of the mechanical behaviour and volumetric deformation mechanisms of remolded and saturated clays. The goal of this thesis is to identify in 3D the local mechanisms which can be activated at the microstructural level in relation to the mechanical loading of clayey meida. The mechanical behaviour of Kaolin k13 is firstly studied at on two loading paths - oedometric and isotropic. Then, an observation protocol was established for the acquisition of three-dimensional images using Scanning Electron Microscopy (SEM) coupled with Focused Ion Beam (FIB). The reconstruction of the images obtained by FIB-SEM allows us to study the 3D geometry of a sub-volume of the sample. The second part consists of developing a quantitative analysis approach in 3D to identify the microstructure properties on different loading paths. The pore morphology is studied using parameters such as flatness, elongation, and sphericity. The orientation of the pores and particles was first identified on 2D images representing cross-sections in the sample and extended to 3D throughout the entire volume for both loading paths. The results obtained in this thesis highlight the contribution of 3D images for a better understanding of the microstructure of saturated remolded clays
Livres sur le sujet "Reconstruction par Patch"
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Fredette, Allison Dorothy. Marriage on the Border. University Press of Kentucky, 2020. http://dx.doi.org/10.5810/kentucky/9780813179155.001.0001.
Texte intégralRésumé :
Not quite the Cotton Kingdom or the free labor North, the mid-nineteenth-century border South was a land in between. There, the clashing ideologies of this era—slavery and freedom, urban and rural, industrial and agrarian—met, merged, and melded. As they did, they formed something new—a fluid, flexible identity that somehow grew from these tensions while rising above them. This border identity would play a critical role in these states’ experiences during the secession crisis, the Civil War, and Reconstruction. Yet, this story—one of political division, internal warfare, and economic struggles—is only one part of the border South’s larger saga. Focusing on the heart of this complicated region, Marriage on the Border reveals how this border environment shaped the lives and loves of Kentuckians, West Virginians, and Appalachian Virginians. Inundated with conflicting messages about marriage, divorce, and gender, these border southerners set their own path. In an era when advice manuals urged all Americans to adopt new ideals of companionate marriage and loving mutuality, border southerners proved especially receptive to these notions. Additionally, when these marriages crumbled, border southerners found ways to divorce more easily than other southerners of this era. Marriage on the Border follows border southerners through their courtships and into their homes, through blissful marriages and turbulent divorce dramas, through secession, war, and reconstruction. Along the way, Marriage on the Border captures the turmoil and confusion of this era, not in its legislative halls or on the battlefield, but in the households of those who lived at the heart of the country.
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Berghahn, Volker R. Journalists between Hitler and Adenauer. Princeton University Press, 2018. http://dx.doi.org/10.23943/princeton/9780691179636.001.0001.
Texte intégralRésumé :
This book takes an in-depth look at German journalism from the late Weimar period through the postwar decades. Illuminating the roles played by journalists in the media metropolis of Hamburg, the book focuses on the lives and work of three remarkable individuals: Marion Countess Dönhoff, distinguished editor of Die Zeit; Paul Sethe, “the grand old man of West German journalism”; and Hans Zehrer, editor in chief of Die Welt. All born before 1914, Dönhoff, Sethe, and Zehrer witnessed the Weimar Republic's end and opposed Hitler. When the latter seized power in 1933, they were, like their fellow Germans, confronted with the difficult choice of entering exile, becoming part of the active resistance, or joining the Nazi Party. Instead, they followed a fourth path—“inner emigration”—psychologically distancing themselves from the regime, their writing falling into a gray zone between grudging collaboration and active resistance. During the war, Dönhoff and Sethe had links to the 1944 conspiracy to kill Hitler, while Zehrer remained out of sight on a North Sea island. In the decades after 1945, all three became major figures in the West German media. The book considers how these journalists and those who chose inner emigration interpreted Germany's horrific past and how they helped to morally and politically shape the reconstruction of the country. With fresh archival materials, the book sheds essential light on the influential position of the German media in the mid-twentieth century and raises questions about modern journalism that remain topical today.
Chapitres de livres sur le sujet "Reconstruction par Patch"
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Walerski, Konrad. « From East to West. Modernization in the Western and Northern Territories of Poland (1944–1989) ». Dans Roadblocks to the Socialist Modernization Path and Transition, 33–62. Cham : Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-37050-2_2.
Texte intégralRésumé :
AbstractAt the end of World War II (1943–1945), the Soviet Union appropriated the eastern parts of Poland, while part of Germany was incorporated into the remaining Polish territory. This was a revolutionary transformation. The German population of Silesia, Pomerania, and Eastern Prussia was replaced by Poles mainly from the Polish eastern territories. This initiated a process of organizing a new social and economic reality in a socialist way: settlement, reconstruction of towns and villages, industry, administration, education, and encounters of different social groups, regional cultures, and mentalities. Till the end of the 1970s, these regions were seen by Polish sociologists as social laboratory in which the process of “Soviet-inspired modernization” took place at high speed.
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Xiaojun, Hu. « Rediscovering Ancient China’s Sword-Making Techniques : Insights from Reconstructing a Han-Dynasty Ring-Pommel Dao ». Dans Martial Culture and Historical Martial Arts in Europe and Asia, 201–38. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2037-0_7.
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AbstractSunzi said, “Warfare is pivotal to the state. [It is] a milieu where life and death are decided, [it holds] the path to survival or extermination and cannot be neglected.” In like manner, the Commentary of Zuo (Zuozhuan) states, “Rituals and warfare are of vital importance to the state.” From this we see that besides ritual matters, such as ancestor worship and maintaining the temples, rulers in ancient China considered warfare and military training to be of utmost importance. Consequently, much attention was paid to sacrificial implements and weapons of war. The production and maintenance of arms was an integral part of this effort as it impacted state security as a whole. The study of ancient arms therefore not only teaches us about ancient weaponry and methods of combat but also yields unique insights into the technology and organization of war. The principal short-range weapons during the Han dynasty were jian (double-edged sword)and dao (single-edged sword), while the latter gradually replaced the jian in military use as the dynasty wore on, partly as a result of the rise of cavalry. This paper contains three parts: iron smelting and weapon production in the Han dynasty; the ancient techniques of iron smelting in shaft furnace; and reconstructing the Han ring-pommel dao with ancient methods.
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Gawrich, Andrea, et Doris Wydra. « Conditions and Contestation : Ukraine on Its Way to EU-Membership ». Dans The War Against Ukraine and the EU, 161–88. Cham : Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-35040-5_8.
Texte intégralRésumé :
AbstractRussia’s attack on Ukraine in February 2022 has not only brought war back to the European continent, it has also created a new urgency for the European Union to allow new members to find economic and strategic protection within its confines. While no accession procedure has been successfully concluded since 2013, the list of candidates is growing. In June 2022, the European Council decided to grant the status of candidate country to both Ukraine and the Republic of Moldova. This was greeted with great enthusiasm, in particular in Ukraine—which now expects a swift accession in reward for the enormous price it has had to pay for its European choice.The key question this chapter addresses is which dynamics have evolved in this early accession process under the conditions of war, where the EU strives to defend the rule of law and democracy internally and externally simultaneously (in particular because of past experiences of how vulnerable democratic achievements are to recession), while at the same time trying to prove its geopolitical capacities by providing credible accession perspectives. The literature on EU conditionality provides us with helpful insights into factors conducive to the transformation of a candidate country along EU conditions (e.g. clarity, tangibility of rewards, absence of veto-players). This seems to make Ukraine an ideal candidate for successful transformation, as the renewed emphasis of the ‘geopolitical’ EU on enlargement strengthens the credibility of the promise, and a renewed enlargement methodology contributes to clarity and increases (tangible) rewards along the way. Additionally, an active Ukrainian civil society is putting pressure on political elites to continue on their European path. The close linkage of EU accession with reconstruction plans for Ukraine also makes successful EU integration an effective remedy for domestic challenges.We argue, however, that in order to comprehensively understand ‘membership politics’ and the politicisation of EU conditions, it is essential to address the contextual interpretation of the norms posed by the EU as part of its accession conditionality. For this, we combine the concept of conditionality with approaches to norm contestation from International Relations (IR) Research. This induces a shift of perspective from a unidirectional norm-giver/norm-taker perspective, closely assigned to conditionality approaches, towards a focus on the web of interactions between actors on the EU and the Ukrainian side as they engage with, interpret and enact norms based on their social context. By example of the reform of the Ukrainian judiciary (and here in particular the Constitutional Court of Ukraine) we show how the ‘sovereignty argument’ is put forward to challenge the “West’s right to evaluate”. Furthermore, the contestation of time frames is of high salience not only because Ukraine demands a ‘fast track accession’ against the will of some EU Member States, but also because it raises the stakes as to how ‘sufficient progress’ for gaining promised rewards is assessed. It is thus indispensable to conceptualise and address contestation in order to understand the current challenges of turning Ukraine’s candidate status into a meaningful membership perspective under increased geopolitical pressure, and while a war is raging on the EU’s doorstep.
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« Chapter 7 : The Betrayal of the Negro : Black Accommodation and Black Protest in the Era of Jim Crow ». Dans Schlager Anthology of Black America. Schlager Group Inc., 2021. https://doi.org/10.3735/9781935306627.book-part-094.
Texte intégralRésumé :
The Reconstruction era offered African Americans in the South something they had long been denied but had always wanted: an equal chance. The passing of the Thirteenth, Fourteenth, and Fifteenth Amendments laid a path for African Americans towards equality and guaranteed them equal treatment under the law. Yet as quickly as hopes were raised, they were dashed: the South had been restored to status quo antebellum, “how it was before the war.” The adoption of Black codes to curtail African American freedoms, the rise of white supremacist groups like the Ku Klux Klan, and the Compromise of 1877 that ended Reconstruction all but sealed the fate of Black Americans who were left with a feeling of betrayal by the federal government that they had put their trust in. The era of Jim Crow, named after a racist character depicted by white performer Thomas D. Rice, created two schools of Black thought that looked to define how Blacks in America should forge ahead: accommodation or protest.
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« Rationalization of Key Industries and the Nurturing of New Industries ». Dans A History of Japanese Trade and Industry Policy, sous la direction de Mikio Sumiya, 289–344. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780198292517.003.0016.
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Abstract Revision of the Anti-Monopoly Law was an important part of the review of Occupation-inspired legislation and regulation authorized by the May 19 51 directive of General Ridgway. The stringent provisions of the law were considered unsuitable for reconstructing the economy. A study by the Advisory Committee on Government Ordinance was initiated immediately, but the path to revision was full of twists and turns.
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Whitmore, Aleysia K. « Frames ». Dans World Music and the Black Atlantic, 151–75. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190083946.003.0006.
Texte intégralRésumé :
Part III examines who world music audiences are and what draws them to Orchestra Baobab and AfroCubism. This chapter sets the scene by offering an ethnography of world music performance venues in Europe and North America. Orchestra Baobab and AfroCubism have performed at Bonaroo, Jazz à Marciac, and WOMAD. They have shared venues with Prince and fun., classic and avant-garde jazz, and Nigerian funk. Venues experiment with how performers can fit into and expand their market niche and image (e.g., cutting edge, worldly, charitable) as they look to attract the most (and right kind of) audiences. The chapter argues that heterogeneous performance frames do not just help redefine the world music genre culture. They offer a path to the label’s destruction—and the music’s reconstruction as a more mainstream genre culture.
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Mouré, Kenneth. « The Franc in Peril, 1924–1926 ». Dans The Gold Standard Illusion, 70–100. Oxford University PressOxford, 2002. http://dx.doi.org/10.1093/oso/9780199249046.003.0005.
Texte intégralRésumé :
Abstract The French path from wartime inflation and budget deficits through the years of major reconstruction of devastated areas to stable currency and finance after 1926 was far from exemplary From early 1924 to mid-1926, France made significant progress in eliminating the budget deficit, but increased taxation and tighter control on expenditure were decided as a product of sharp crises. The franc, having fallen dramatically in 1919–20, tell by a further 50 per cent in this period. and parliament voted the toughest tax measures in seeking to end flight from the franc. The unwillingness of French politicians to vote tax increases vas a persistent factor producing financial and monetary instability. The resolution of the currency crises in March 1924 and July 1926 owed a great deal to the crises having confronted politicians with a worse alternative than voting new taxes: collapse of the franc. But successful resolution of the crises depended on co-ordinated action between the central bank and the government, as the crises were in part a product of conflict between the Bank of France and the Treasury.
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Tolson, Franita. « Eulogizing Section 5 ». Dans The Oxford Handbook of American Election Law, 771–94. Oxford University Press, 2024. http://dx.doi.org/10.1093/oxfordhb/9780197547922.013.6.
Texte intégralRésumé :
Abstract Contemporary narratives portray the preclearance regime of the Voting Rights Act of 1965 as a phoenix, emerging from the ashes of the Fifteenth Amendment, which swooped in and saved minority voters from the totalitarianism of the one-party South. An overlooked, and indeed, forgotten, part of this story was that Sections 4(b) and 5 of the Act were products of lessons learned from the post-Civil War political order. These lessons shaped both the scope and structure of the Voting Rights Act, and importantly, they also provided a roadmap for confronting the inevitable challenges that the Act would face in the wake of its enactment. Reconstruction era legislation and constitutional amendments—like the Voting Rights Act—were targeted toward southern states hostile to the enfranchisement of Black people. These provisions also faced challenges from a U.S. Supreme Court increasingly concerned about intrusions on state sovereignty. Looking to history, Congress crafted the 1965 Act to withstand the assaults that had befallen its earlier efforts to protect the right to vote. As we are once again confronted with circumstances that are eerily resonant of the suppression efforts of days past, Congress must be fully cognizant of the lessons to be learned from this history. The historical record shows that the path forward for the Voting Rights Act cannot simply be about reauthorizing or reworking Sections 4(b) and 5. Honoring the legacy of the Act demands, at a minimum, amending the Constitution to explicitly protect the right to vote.
Actes de conférences sur le sujet "Reconstruction par Patch"
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Yang, Tachung, et Cheng-Chung Wang. « A GC2 Joining Procedure for B-Spline Patches in Reverse Engineering ». Dans ASME 1997 Turbo Asia Conference. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/97-aa-044.
Texte intégralRésumé :
Reconstruction of surface models is a vital part in reverse engineering. Because of the huge amount of data from Coordinate Measuring Machine (CMM), processes for division of data into groups, surface patch reconstruction, and patch joining are inevitable in the CAD systems tailored for reverse engineering applications. Existing techniques of surface patch joining have the disadvantages, such as computational complication or lack of desired geometric continuity. A GC2 joining technique for B-spline surface patches by utilising a Bezier patch joining technique was proposed in this paper. This method possesses the merits in which only the control vertices near the joining boundaries of patches are modified and no additional blending surfaces at the joints of patches are created.
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Gotthans, Tomas, Roman Marsalek et Jakub Gotthans. « Wideband digital predistortion with sub-Nyquist nonuniform sampling and reconstruction of feedback path ». Dans 2017 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications (PAWR). IEEE, 2017. http://dx.doi.org/10.1109/pawr.2017.7875576.
Texte intégral
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Kutzer, Michael D., Levi D. DeVries et Cooper D. Blas. « Part Monitoring and Quality Assessment of Conformal Additive Manufacturing Using Image Reconstruction ». Dans ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85370.
Texte intégralRésumé :
Additive manufacturing (AM) technologies have become almost universal in concept development, prototyping, and education. Advances in materials and methods continue to extend this technology to small batch and complex part manufacturing for the public and private sectors. Despite the growing popularity of digital cameras in AM systems, use of image data for part monitoring is largely unexplored. This paper presents a new method for estimating the 3D internal structure of fused deposition modeling (FDM) processes using image data from a single digital camera. Relative transformations are established using motion capture, and the 3D model is created using knowledge of the deposition path coupled with assumptions about the deposition cross-section. Results show that part geometry can be estimated and visualized using the methods presented in this work.
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Šimun, Miroslav, Ante Bajić, Davor Marković et Luka Jurčević. « Reconstruction of the Jarunska road in Zagreb after the earthquake ». Dans 8th International Conference on Road and Rail Infrastructure, 463–71. University of Zagreb Faculty of Civil Engineering, 2024. http://dx.doi.org/10.5592/co/cetra.2024.1564.
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The paper analyzes the condition of the road surface of Alley Matija Ljubek in the city of Zagreb, the road around Lake Jarun. The Jarun road was built as part of the development of the Jarun Sports and Recreation Center for the Universiade in 1987. It’s 6.4 kilometers long and has one-way traffic for cars, a parking lot, as well as a separate path for bicycles and pedestrians. During 33 years of exploitation, a number of damages appeared on the roadway, which were further aggravated by seismic activities in the area of the city of Zagreb in 2020. As part of the preparation of the roadway renovation study, measurements of parameters were carried out: roughness index, route depth, macrotexture, cracks and patches on the pavement. After analyzing the measured characteristics of the driving surface, a proposal was made for the renovation of the Alley Matija Ljubek pavement. To apply for the allocation of non-reimbursable financial resources aimed at restoring the infrastructure to its proper condition, a detailed scope of work for repairing damages to the Alley Matija Ljubek road, funded by the European Union Solidarity Fund through Shoo, has been elaborated. The road was renovated in the spring of 2023 in agreement with the renovation project and with a high-quality approach to maintaining technical accuracy, safety and driving comfort. As a result, the road now has a new lifecycle for exploitation.
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Saglio, Emilio, Ferruccio Mandorli et Umberto Cugini. « Super-Finishing Tool Path Generation for Digitized Models Supported by Super-Finishing Form Feature Recognition ». Dans ASME 1994 International Computers in Engineering Conference and Exhibition and the ASME 1994 8th Annual Database Symposium collocated with the ASME 1994 Design Technical Conferences. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/cie1994-0399.
Texte intégralRésumé :
Abstract The realization of sculptured shapes using CAD systems is still today a very complex and time consuming operation. For these reasons, design by physical modeling is still in use and remains in force in many industries (automotive, ski boots, sport articles). For the manufacturing of complex free-form surfaces, in situations in which it is more desirable to proceed from a physical model to a numerical definition rather than use mathematics to derive the physical part, copy milling techniques are widely used. This paper gives a brief overview about copy milling techniques for 3 axis copy milling machines, and proposes a feature based method to support an automatic tool path generation for the super-finishing phase. The proposed method is divided in two parts: super-finishing features recognition and tool path generation. Using copy milling techniques, the model of the object to be milled is obtained by digitizing. Therefore a global mathematical surface description of the model does not exist. In such a situation a model interpretation phase is required to recognize the super-finishing features and thus proceed to the tool path generation. A two step algorithm for super-finishing feature recognition on a digitized model is proposed: features arc recognized on the basis of the digitized point density and the normal vectors of the triangles generated by the surface reconstruction (based on Delaunay triangulation method). The tool path is then generated using a method based on the calculation of the Voronoi diagram on the area identified as super-finishing feature. The super-finishing feature recognition and tool path generation modules have been integrated as part of a more general CAM system for copy milling called HICAM. The architecture of such a system will be presented together with examples of solutions obtained by means of the use of the implemented prototype modules.
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McDonald-Bowyer, A., S. Dietsch, E. Dimitrakakis, J. Coote, L. Lindenroth, D. Stoyanov et A. Stilli. « Towards Autonomous Robotic Ultrasound Scanning using Pneumatically Attachable Flexible Rails ». Dans The Hamlyn Symposium on Medical Robotics : "MedTech Reimagined". The Hamlyn Centre, Imperial College London London, UK, 2022. http://dx.doi.org/10.31256/hsmr2022.19.
Texte intégralRésumé :
Robotic-assisted partial nephrectomy (RAPN) is a surgi- cal procedure that employs robotics to remove a portion of diseased kidney. During the procedure, a drop-in Ultrasound (US) probe is used to identify the resec- tion margins. Although the robot facilitates the task, the scanning of the kidney proves challenging due to slippage and requires a highly skilled surgeon [1]. In previous work [2], we presented a Pneumatically Attach- able Flexible (PAF) rail to enable stable, track-guided US scanning of the kidney during RAPN. In [3] and [4], we have investigated the autonomous deployment of the PAF rail on the surface of the organ and their use in intraoperative organ manipulation. In [5], Wang et al. studied the 3-D reconstruction of a mass embedded in a kidney phantom when the PAF rail guides the US probe. In this work, we investigate autonomous control during the US scanning using the PAF rails, specifically using fibre-optic shape-sensing data as the input for path- planning. First, we present the design and fabrication of the sensorized PAF rail; then we assess the performance of real-time curvature sensing with the sensorized PAF rail system on rigid and soft phantoms; finally, we demonstrate how the PAF rail local shape data can be used to plan a trajectory and autonomously guide an intraoperative US probe.
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Steuben, J. C., J. G. Michopoulos, A. P. Iliopoulos, B. D. Graber et A. J. Birnbaum. « Multiscale Tomographic Wave-Matter Interaction Modeling to Enable Artifact-Free Material Defect Reconstruction ». Dans ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/detc2020-22474.
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Abstract The fabrication and subsequent in-service excitation of materials/structures invariably generates significant defects including cracks, voids and inclusions, spanning many length scales. The various technologies available for detecting and qualitatively describing such defects suffer from the introduction of various degrees inaccuracy when it comes to the quantification of defect geometry. This can have an adverse impact on modeling and understanding how the material/part/structure performance is effected by these defects. The main cause of this shortcoming is that aspects of the physical processes used to interrogate the material system, using monochromatic or polychromatic waves such as X-ray, mm-wave, or ultrasound, are not taken into account. These waves interact with the multiscale defect ensemble in a complex fashion that inevitably produces spurious “artifacts” in the resulting data, which cannot be removed via conventional data post-processing. These artifacts then introduce unacceptable levels of error when reconstructing defect geometry and computing the remaining lifespan of defect-bearing materials/structures. The present work introduces preliminary efforts towards a multiscale modeling and simulation framework for capturing the interactions of waves (such as X-rays) with materials bearing defect ensembles. It is shown that conventional approaches such as ray tracing are not adequate, and a more robust solution to the relevant wave equations utilizing the Finite Element discretization is employed. A general parameterization of defect geometries based on superquadratic functions is also introduced, and the interactions of defects modeled in this fashion with X-rays are investigated. It is also shown that this combination of parameterization and modeling techniques allows the recovery of true, artifact-free defect geometry utilizing classical inverse methods. The methodology is demonstrated using synthetic tomographic data, and the path forward to a more complete realization of this technology is outlined.
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Llanes, Jose Damian, Alejo Viñales et Juan Juri. « Assisted 3D Model Construction and Facies Propagation in Golfo San Jorge Basin Reservoirs for Modelling EOR ». Dans SPE Improved Oil Recovery Conference. SPE, 2022. http://dx.doi.org/10.2118/209400-ms.
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Abstract Three-dimensional modelling is at the critical path to map the by-passed oil in multilayer fluvial systems in the San Jorge Basin. Integrated reservoir modelling teams dedicate an important amount of time to create these three-dimensional models to decrease risk pursuing chemical injection for enhanced oil recovery. Traditional static reservoir modelling requires an important effort from the geologist to construct the interwell correlation. The objective of this work is to show the implementation of two unsupervised algorithms to automate/assist integrated reservoir modelling. We create multiple possible three-dimensional models of real multilayer static reservoirs and accelerate simulation. The first part of the work obtains the stratigraphic representation of the entire reservoir structure. We use the available lithology well logs as spontaneous potential and gamma ray to identify automatically the permeable and shale rocks with unbiased interpretation by their deflection responses in each well for the entire target reservoirs. Then we construct a graph in which each of the deflections is represented by a node. The edges that join each pair of nodes have an assigned weight depending on the difference in depth and the distance in plan of the nodes. We draw edge weights from a multivariate distribution with interwell distances and dipping angle. Then we use an adapted version of the Girvan-Newman algorithm to make a community detection by eliminating nongeological connections/features, to find the community with greater modularity. These communities represent the existing correlations between the deflections of the different wells. In the second part of this work, we obtain the facies distribution in the reservoir, using one-, two- and three-dimensional Markov chains. We implemented Jaccard distance to measure the mismatch of geological features and objects between the true synthetic case and the reconstructed model. With the modified Girvan-Newman algorithm we obtained multiple stratigraphic representations similar to the 3D model created by a geologist. Through modeling of two incomplete synthetic cross section cases using Markov chain propagation of a transition matrix the reconstruction reveals that we recover 90% of the original case even when we Input only 5% of the true data initially in the model. Then we tested a very fine real three-dimensional case created by an experienced geologist. The Markov reconstruction algorithm was able to recover up to 60 percent of the model true real three-dimensional model. The analysis of the reconstructed model features reveals that the Jaccard distance is a reliable indicator of the geological features. Using the computational algorithms implemented, it is possible to obtain a stratigraphic model and the facies model in less than four hours speeding up reservoir modeling. And core data is sufficient to recover a reasonable model to input to the simulator.
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Berthold, Martin, Hervé Morvan, Richard Jefferson-Loveday, Benjamin C. Rothwell et Colin Young. « Multiphase CFD Modeling of External Oil Flow From a Journal Bearing ». Dans ASME Turbo Expo 2018 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-77130.
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High loads and bearing life requirements make journal bearings a potential choice for use in high power, epicyclic gearboxes in jet engines. Particularly in a planetary configuration the kinematic conditions are complex. With the planet gears rotating about their own axis and orbiting around the sun gear, centrifugal forces generated by both motions interact with each other and affect the external flow behavior of the oil exiting the journal bearing. Computational Fluid Dynamics (CFD) simulations using the Volume of Fluid (VoF) method are carried out in ANSYS Fluent [1] to numerically model the two-phase flow behavior of the oil exiting the bearing and merging into the air surrounding the bearing. This paper presents an investigation of two numerical schemes that are available in ANSYS Fluent to track or capture the air-oil phase interface: the geometric reconstruction scheme and the compressive scheme. Both numerical schemes are used to model the oil outflow behavior in the most simplistic approximation of a journal bearing: a representation, rotating about its own axis, with a circumferentially constant, i.e. concentric, lubricating gap. Based on these simplifications, a three dimensional (3D) CFD sector model with rotationally periodic boundaries is considered. A comparison of the geometric reconstruction scheme and the compressive scheme is presented with regards to the accuracy of the phase interface reconstruction and the time required to reach steady state flow field conditions. The CFD predictions are validated against existing literature data with respect to the flow regime, the direction of the predicted oil flow path and the oil film thickness. Based on the findings and considerations of industrial requirements, a recommendation is made for the most suitable scheme to be used. With a robust and partially validated CFD model in place, the model fidelity can be enhanced to include journal bearing eccentricity. Due to the convergent-divergent gap and the resultant pressure field within the lubricating oil film, the outflow behavior can be expected to be very different compared to that of a concentric journal bearing. Naturally, the inlet boundary conditions for the oil emerging from the journal bearing into the external environment must be consistent with the outlet conditions from the bearing. The second part of this paper therefore focuses on providing a method to generate appropriate inlet boundary conditions for external oil flow from an eccentric journal bearing.
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Li, Yanqun, Hong Geng et Erpeng Shi. « Response Path Adapted to the Unbalanced Shrinkage of Small Towns in Metropolitan Areas ». Dans 55th ISOCARP World Planning Congress, Beyond Metropolis, Jakarta-Bogor, Indonesia. ISOCARP, 2019. http://dx.doi.org/10.47472/aeut4486.
Texte intégralRésumé :
Along with the global wave of urbanization, urban agglomerations with megacities as the core have become the main form of urbanization in various countries. The polarization effect around the metropolis leads to the centripetal flow of capital, labour, land and other resource elements in the surrounding small towns, which causes the shrinkage of small towns in the metropolis, such as population reduction, economic recession, idle housing and dilapidated space. The shrinkage of small towns in the metropolis has become a global issue. However, as an important spatial unit in the spectrum of urbanization that serves, connects and couples urban and rural areas, the shrinking phenomenon faced by small towns has an important influence on the healthy development of urbanization. Exploring the development path of adaptive shrinkage for small towns has become an important part of the healthy urbanization of metropolises. Based on the public data of population, land and economy in Wuhan, China from 2004 to 2014, this paper uses GIS and other spatial analysis technologies to comprehensively measure the relevant characteristics of the shrinkage of small towns. The results showed that the small towns in Wuhan are in the form of "unbalanced shrinkage" under a local growth. And the towns present a spatial pattern of "circle increasing shrinkage" around the boundary of main downtown. With a further exploration of the formation mechanism of "unbalanced shrinkage", it is found that this shrinkage pattern is caused by a combination function of various factors, such as downtown deprivation in the policies supply, centripetal delivery of social capital and reconstruction of regional division of labour network. Based on this, this paper tries to propose some response paths for small towns in metropolitan areas to adapt to the "unbalanced shrinkage". First of all, the small towns should integrate into the regional differential development pattern and strive for the institutional dividend. Secondly, the small towns should promote an industrial transformation, and then attract the market release of social capital. Thirdly, the small towns should improve the living environment and promote intensive use of land. Through these paths, we can stabilize the three-level structure system of “urban-township-village”, and ensure the healthy urbanization of metropolitan areas.