Matrix-based implementation and GPU acceleration of linearized ordinary state-based peridynamic models in MATLAB

Ordinary state-based peridynamic (OSB-PD) models have an unparalleled capability to simulate crack propagation phenomena in solids with arbitrary Poisson's ratio. However, their non-locality also leads to prohibitively high computational cost. In this paper, a fast solution scheme for OSB-PD models based on matrix operation is introduced, with which, the graphics processing units (GPUs) are used to accelerate the computation. For the purpose of comparison and verification, a commonly used solution scheme based on loop operation is also presented. An in-house software is developed in MATLAB. Firstly, the vibration of a cantilever beam is solved for validating the loop- and matrix-based schemes by comparing the numerical solutions to those produced by a FEM software. Subsequently, two typical dynamic crack propagation problems are simulated to illustrate the effectiveness of the proposed schemes in solving dynamic fracture problems. Finally, the simulation of the Brokenshire torsion experiment is carried out by using the matrix-based scheme, and the similarity in the shapes of the experimental and numerical broken specimens further demonstrates the ability of the proposed approach to deal with 3D non-planar fracture problems. In addition, the speed-up of the matrix-based scheme with respect to the loop-based scheme and the performance of the GPU acceleration are investigated. The results emphasize the high computational efficiency of the matrix-based implementation scheme.Comment: 32 pages, 16 figure

R3^3-Net: A Deep Network for Multi-oriented Vehicle Detection in Aerial Images and Videos

Vehicle detection is a significant and challenging task in aerial remote sensing applications. Most existing methods detect vehicles with regular rectangle boxes and fail to offer the orientation of vehicles. However, the orientation information is crucial for several practical applications, such as the trajectory and motion estimation of vehicles. In this paper, we propose a novel deep network, called rotatable region-based residual network (R$^3$-Net), to detect multi-oriented vehicles in aerial images and videos. More specially, R$^3$-Net is utilized to generate rotatable rectangular target boxes in a half coordinate system. First, we use a rotatable region proposal network (R-RPN) to generate rotatable region of interests (R-RoIs) from feature maps produced by a deep convolutional neural network. Here, a proposed batch averaging rotatable anchor (BAR anchor) strategy is applied to initialize the shape of vehicle candidates. Next, we propose a rotatable detection network (R-DN) for the final classification and regression of the R-RoIs. In R-DN, a novel rotatable position sensitive pooling (R-PS pooling) is designed to keep the position and orientation information simultaneously while downsampling the feature maps of R-RoIs. In our model, R-RPN and R-DN can be trained jointly. We test our network on two open vehicle detection image datasets, namely DLR 3K Munich Dataset and VEDAI Dataset, demonstrating the high precision and robustness of our method. In addition, further experiments on aerial videos show the good generalization capability of the proposed method and its potential for vehicle tracking in aerial videos. The demo video is available at https://youtu.be/xCYD-tYudN0

Anti-inflammatory effect of Zanthoxylum bungeanum-cake-separated moxibustion on rheumatoid arthritis rats

Background: Zanthoxylum bungeanum-cake-separated moxibustion (ZBCS-moxi), a kind of traditional therapy of moxibustion, has been used in China since 340 B.C. However, its mechanism remains unclear. So, this study was attempted to reveal the anti-inflammatory effect of ZBCS-moxi on rheumatoid arthritis (RA) rats.Methods and Materials: Forty health SD female rats were randomly divided into 4 groups  (n=10/group): control group, model group, Zanthoxylum bungeanum-cake-separated moxibustion group (ZBCS-moxi group) and Aconitum carmichaeli-cake-separated moxibustion group (ACCS-moxi group). RA model was induced by injecting 0.1 ml Freund’s complete adjuvant (FCA) into the right hind paw of rats. Eleven days after CFA injection, the rats in ZBCS-moxi group received Zanthoxylum bungeanum- cake-separated moxibustion on Shenshu (BL23), Zusanli (ST36) acupoints and the dorsum right hind paw respectively for 3 weeks. The ACCS-moxi group was used as a positive control, while the rats were treated with Aconitum carmichaeli-cake-separated moxibustion on the same acupoints and courses. After a 3-week treatment, we investigated anti-inflammatory effect by measuring the paw volume,  observing the pathologic morphology of synovial membranes and detecting the concentration of IL-1β and TNF-α in serum.Results: Compared to model group, the swollen paw volumes, the synovial hyperplasia and pannus formation of synovial membranes and the concentration of IL-1β and TNF-α in serum decreased obviously (P<0.01, P<0.05) in ZBCS-moxi group, as well as in ACCS-moxi group. However, the swollen paw volumes, the synovial hyperplasia and pannus formation of synovial membranes and the concentration of IL-1β and TNF-α in serum in ZBCS-moxi and ACCS-moxi group did not show significant differences (P>0.05)Conclusions: ZBCS-moxi displays anti-inflammatory effect on RA rats via suppressing the expression of cytokines and has similar effect to ACCS-moxi.Key words: Anti-inflammatory effect; Zanthoxylum bungeanum-cake-separated moxibustion; Aconitum carmichaeli-cake-separated moxibustion; Rheumatoid Arthritis

ANTI-INFLAMMATORY EFFECT OF ZANTHOXYLUM BUNGEANUM-CAKE-SEPARATED MOXIBUSTION ON RHEUMATOID ARTHRITIS RATS

Background: Zanthoxylum bungeanum-cake-separated moxibustion (ZBCS-moxi), a kind of traditional therapy of moxibustion, has been used in China since 340 B.C. However, its mechanism remains unclear. So, this study was attempted to reveal the anti-inflammatory effect of ZBCS-moxi on rheumatoid arthritis (RA) rats. Methods and Materials: Forty health SD female rats were randomly divided into 4 groups (n=10/group): control group, model group, Zanthoxylum bungeanum-cake-separated moxibustion group (ZBCS-moxi group) and Aconitum carmichaeli-cake-separated moxibustion group (ACCS-moxi group). RA model was induced by injecting 0.1 ml Freund’s complete adjuvant (FCA) into the right hind paw of rats. Eleven days after CFA injection, the rats in ZBCS-moxi group received Zanthoxylum bungeanum- cake-separated moxibustion on Shenshu (BL23), Zusanli (ST36) acupoints and the dorsum right hind paw respectively for 3 weeks. The ACCS-moxi group was used as a positive control, while the rats were treated with Aconitum carmichaeli-cake-separated moxibustion on the same acupoints and courses. After a 3-week treatment, we investigated anti-inflammatory effect by measuring the paw volume, observing the pathologic morphology of synovial membranes and detecting the concentration of IL-1β and TNF-α in serum. Results: Compared to model group, the swollen paw volumes, the synovial hyperplasia and pannus formation of synovial membranes and the concentration of IL-1β and TNF-α in serum decreased obviously (

The Tianlai Cylinder Pathfinder array: System functions and basic performance analysis

The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe, with the ultimate aim of mapping the large scale structure and measuring cosmological parameters such as the dark energy equation of state. Each of its three parallel cylinder reflectors is oriented in the north-south direction, and the array has a large field of view. As the Earth rotates, the northern sky is observed by drift scanning. The array is located in Hongliuxia, a radio-quiet site in Xinjiang, and saw its first light in September 2016. In this first data analysis paper for the Tianlai cylinder array, we discuss the sub-system qualification tests, and present basic system performance obtained from preliminary analysis of the commissioning observations during 2016-2018. We show typical interferometric visibility data, from which we derive the actual beam profile in the east-west direction and the frequency band-pass response. We describe also the calibration process to determine the complex gains for the array elements, either using bright astronomical point sources, or an artificial on site calibrator source, and discuss the instrument response stability, crucial for transit interferometry. Based on this analysis, we find a system temperature of about 90 K, and we also estimate the sensitivity of the array

Applications des approches d'homogénéisation à la modélisation tridimensionnelle de l'endommagement des matériaux quasi fragiles (formulations, validations et implémentations numériques)

Cette étude concerne des modélisations micromécaniques d'endommagement par muItifissuration des géomatériaux quasi fragiles. Le cadre général est celui des méthodes de changement d'échelle combinées à la thermodynamique adoptée pour la formulation des lois d'endommagement. On rappelle et analyse d'abord au chapitre 1 les différents schémas d'homogénéisation (schéma dilué, schéma Mori-Tanaka et celui de Ponte Castaneda et Willis) et leurs applications dans le contexte des milieux microfissurés. Au chapitre 2, après avoir examiné et comparé deux approches (l'une discrète, l'autre par intégration numérique de type Gauss) traitant de la généralisation des résultats à un système quelconque de fissures, on propose une formulation complète de modèles d'endommagement anisotrope incluant les effets de contact unilatéral, l'interaction entre fissures ainsi que la distribution spatiale des fissures. Les prédictions des modèles d'endommagement associés aux différents schémas d'homogénéisation, sont confrontées à des données sur deux bétons. Au chapitre 3, on traite du couplage entre l'endommagement anisotrope et les phénomènes de dissipation par frottement sur les lèvres des microfissures fermées. L'étude détaillée des divers degrés de couplage (endommagement, glissement et dilatance associée) et du rôle de différents schémas d'homogénéisation est réalisée pour un système de fissures parallèles. L'analyse est ensuite étendue à une distribution quelconque et appliqué à deux roches quasi fragiles en sollicitations muItiaxiales. L'implémentation des modèles micro-macro développés dans un code éléments finis ainsi que l'analyse des structures dégradées font l'objet du dernier chapitre.LILLE1-BU (590092102) / SudocSudocFranceF

Micromechanics of rock damage: Advances in the quasi-brittle field

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