scholarly journals Three Dimensional Adaptive Method for Compressible Multi-Fluids Flows

2010 ◽  
Author(s):  
Hongwei Zheng ◽  
Ning Qin ◽  
Chang Shu
Keyword(s):  
Three Dimensional ◽  
Adaptive Method

Adaptive Detached-Eddy Simulation of Three-Dimensional Diffusers

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Paul Durbin ◽  
Zifei Yin ◽  
Elbert Jeyapaul
Keyword(s):  
Pressure Coefficient ◽  
Three Dimensional ◽  
Side Wall ◽  
Turbulence Models ◽  
Adaptive Method ◽  
Detached Eddy Simulation ◽  
Mean Velocity ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Default Data

An adaptive method for detached-eddy simulation (DES) is tested by simulations of flow in a family of three-dimensional (3D) diffusers. The adaptive method either adjusts the model constant or defaults to a bound if the grid is too coarse. On the present grids, the adaptive method adjusts the model constant over most of the flow, without resorting to the default. Data for the diffuser family were created by wall-resolved, large-eddy simulation (LES), using the dynamic Smagorinsky model, for the purpose of testing turbulence models. The family is a parameterized set of geometries that allows one to test whether the pattern of separation is moving correctly from the top to the side wall as the parameter increases. The adaptive DES model is quite accurate in this regard. It is found to predict the mean velocity accurately, but the pressure coefficient is underpredicted. The latter is due to the onset of separation being slightly earlier in the DES than in the LES.

scholarly journals Unsupervised Subcategory Domain Adaptive Network for 3D Object Detection in LiDAR

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 927
Author(s):  
Zhiyu Wang ◽  
Li Wang ◽  
Liang Xiao ◽  
Bin Dai
Keyword(s):  
Object Detection ◽  
Point Cloud ◽  
Three Dimensional ◽  
Autonomous Driving ◽  
Adaptive Method ◽  
Target Domain ◽  
Adaptive Network ◽  
General Object ◽  
Dimensional Object ◽  
3D Object Detection

Three-dimensional object detection based on the LiDAR point cloud plays an important role in autonomous driving. The point cloud distribution of the object varies greatly at different distances, observation angles, and occlusion levels. Besides, different types of LiDARs have different settings of projection angles, thus producing an entirely different point cloud distribution. Pre-trained models on the dataset with annotations may degrade on other datasets. In this paper, we propose a method for object detection using an unsupervised adaptive network, which does not require additional annotation data of the target domain. Our object detection adaptive network consists of a general object detection network, a global feature adaptation network, and a special subcategory instance adaptation network. We divide the source domain data into different subcategories and use a multi-label discriminator to assign labels dynamically to the target domain data. We evaluated our approach on the KITTI object benchmark and proved that the proposed unsupervised adaptive method could achieve a remarkable improvement in the adaptation capabilities.

Investigation on Mixed Mode Stress Intensity Factors for Inclined Surface Crack in Finite-Thickness Plates and Parameters Influence

2011 ◽  
Vol 217-218 ◽  
pp. 330-335
Author(s):  
Wei Xie ◽  
Shao Wei Tu ◽  
Qi Qing Huang ◽  
Zhi Ping Yin
Keyword(s):  
Stress Intensity ◽  
Mixed Mode ◽  
Finite Thickness ◽  
Plate Thickness ◽  
Three Dimensional ◽  
Adaptive Method ◽  
Mixed Mode Fracture ◽  
Mesh Model ◽  
Mode Stress ◽  
Inclined Surface

In this paper, mixed mode stress intensity factor (SIF) solutions are computed for inclined surface cracks in finite-thickness plates. The S-version finite element method (S-FEM), which is an adaptive method and multi-scale computing method, are employed in the analyses. When S-FEM is applied to solve the fracture problem, local mesh model including cracks can be built independently from the global mesh model for modeling overall structure. The local model is superposed on the g- lobal one. Therefore, it is easy to introduce cracks in an existing mesh model. The influences of inc- lination angles, crack shape and plate thickness on the mixed mode fracture solution were investiga- ted. The solutions presented can be used to assess fail/safe conditions and fatigue crack growth for the three-dimensional cracks studied.

scholarly journals Codec for transfer Maritime Images in Bandwidth Constrained

2020 ◽  
Author(s):  
Ш.С. Фахми ◽  
Ю.Е. Крылов ◽  
Я.А.А. Хасан ◽  
Е.В. Костикова
Keyword(s):  
Three Dimensional ◽  
Adaptive Method ◽  
Video Data ◽  
Video Codec ◽  
Compressed Video ◽  
Discrete Cosine Transformation ◽  
Video Information ◽  
Transmission Errors ◽  
Testing Algorithms ◽  
Spatial Redundancy

В работе представлен видеокодек с адаптивным способом сканирования спектральных трансформант, основанный на применении трехмерных (3D) дискретных косинусных преобразований. Кодек имеет низкую вычислительную сложность и высокую устойчивость к ошибкам передачи по каналу связи и предназначен для мобильных устройств. Кодек представляет собой устройство, которое последовательно выполняет дискретное косинусное преобразование для устранения пространственной избыточности в пределах кадра и временной межкадровой избыточности в последовательности кадров с учетом скорости движения объектов на изображениях морских сюжетов. Приведены результаты моделирования алгоритмов кодирования и декодирования видеоинформации для различных видеопотоков, полученных из камер наблюдения. Получены результаты тестирования алгоритмов кодирования и декодирования изображений в виде графиков зависимости точности восстановления от скорости передачи сжатых видеоданных и зависимости точности от сложности устройств сжатия изображений. This paper presents a video codec with an adaptive method for scanning spectral transformants based on the use of three-dimensional (3D) discrete cosine transformations. The codec has a low computational complexity and high resistance to transmission errors over the communication channel and is designed for mobile devices. A codec is a device that sequentially performs a discrete cosine transformation to eliminate spatial redundancy within a frame and temporal inter-frame redundancy in a sequence of frames, taking into account the speed of movement of objects in images of marine subjects. The results of modeling algorithms for encoding and decoding video information for various video streams obtained from surveillance cameras are presented. The results of testing algorithms for encoding and decoding images in the form of graphs of the dependence of the recovery accuracy on the speed of transmission of compressed video data and the dependence of accuracy on the complexity of image compression devices are obtained.

scholarly journals Pepsi-SAXS: an adaptive method for rapid and accurate computation of small-angle X-ray scattering profiles

2017 ◽  
Vol 73 (5) ◽  
pp. 449-464 ◽  
Author(s):  
Sergei Grudinin ◽  
Maria Garkavenko ◽  
Andrei Kazennov
Keyword(s):  
Small Angle ◽  
Three Dimensional ◽  
Multipole Expansion ◽  
Adaptive Method ◽  
Sampling Theorem ◽  
Large Set ◽  
X Ray ◽  
X Ray Scattering ◽  
Comparable Accuracy ◽  
Ray Scattering

A new method calledPepsi-SAXSis presented that calculates small-angle X-ray scattering profiles from atomistic models. The method is based on the multipole expansion scheme and is significantly faster compared with other tested methods. In particular, using the Nyquist–Shannon–Kotelnikov sampling theorem, the multipole expansion order is adapted to the size of the model and the resolution of the experimental data. It is argued that by using the adaptive expansion order, this method has the same quadratic dependence on the number of atoms in the model as the Debye-based approach, but with a much smaller prefactor in the computational complexity. The method has been systematically validated on a large set of over 50 models collected from the BioIsis and SASBDB databases. Using a laptop, it was demonstrated thatPepsi-SAXSis about seven, 29 and 36 times faster compared withCRYSOL,FoXSand the three-dimensional Zernike method inSAStbx, respectively, when tested on data from the BioIsis database, and is about five, 21 and 25 times faster compared withCRYSOL,FoXSandSAStbx, respectively, when tested on data from SASBDB. On average,Pepsi-SAXSdemonstrates comparable accuracy in terms of χ2toCRYSOLandFoXSwhen tested on BioIsis and SASBDB profiles. Together with a small allowed variation of adjustable parameters, this demonstrates the effectiveness of the method.Pepsi-SAXSis available at http://team.inria.fr/nano-d/software/pepsi-saxs.

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