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Two-Dimensional multi-Domain Hybrid Spectral-WENO Methods for Conservation Laws

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Communications in Computational Physics 2006年第3期1卷 548-574页

作者： Bruno Costa Wai Sun Don David Gottlieb Radislav Sendersky Departamento de Matem´atica Aplicada IM-UFRJCaixa Postal 68530Rio de JaneiroRJC.E.P.21945-970Brazil Division of Applied Mathematics Brown UniversityProvidenceRhode Island 02912USA

The multi-domain hybrid Spectral-WENO method(Hybrid)is introduced for the numerical solution of two-dimensional nonlinear hyperbolic systems in a Cartesian physical domain which is partitioned into a grid of rectangular *** main idea of the Hybrid scheme is to conjugate the spectral and WENO methods for solving problems with shock or high gradients such that the scheme adapts its solver spatially and temporally depending on the smoothness of the solution in a given *** as a multi-domain method,an adaptive algorithm is used to keep the solutions parts exhibiting high gradients and discontinuities always inside WENO subdomains while the smooth parts of the solution are kept inside spectral ones,avoiding oscillations related to the well-known Gibbs phenomenon and increasing the numerical efficiency of the overall scheme.A higher order version of the multi-resolution analysis proposed by Harten is used to determine the smoothness of the solution in each *** also discuss interface conditions for the two-dimensional problem and the switching procedure between WENO and spectral *** Hybrid method is applied to the two-dimensional Shock-Vortex Interaction and the Richtmyer-Meshkov Instability(RMI)problems.

关键词： Spectral WENO multi-resolution multi-domain hybrid conservation laws

Large-Scale Terrain Simplification and Visualization Based on TIN

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Computer Aided Drafting,Design and Manufacturing 2008年第2期18卷 1-8页

作者： KANG Lai, WU Ling-da, YANG Bing, SONG Han-chen (College of Information Systems & Management, National University of Defense Technology, Changsha 410073, China)

In the preprocessing phase, the global terrain model is partitioned into blocks with their feature points being picked out to generate TIN model for each terrain block, then the multi-resolution models of terrain organized in the form of quad-tree is created bottom-up. Cracks between terrain blocks are avoided by inserting vertices to form common boundaries. At run-time, a view-dependent LOD algorithm is used to control the loading and unloading of the proper blocks by an additional synchronous thread. To eliminate the artifacts created by LOD transitions, geomorphing is used in real-time. These rendering strategies increase the throughput of GPU and avoid imbalance of load among CPU, GPU and Disk I/O. Experimental results show that the system can perform visually smooth rendering of large-scale terrain scenes with fine quality at an average rate of 80 fps.

关键词： real-time rendering 3D terrain multi-resolution triangulated irregular network quad-tree

An Improvement of Pedestrian Detection Method with multiple resolutions

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Journal of Computer and Communications 2017年第9期5卷 102-116页

作者： Guodong Zhang Peilin Jiang Kazuyuki Matsumoto Minoru Yoshida Kenji Kita Faculy and School of Engineering Tokushima University Tokushima Japan Xi’an Jiaotong University Xian China

In object detection, detecting an object with 100 pixels is substantially different from detecting an object with 10 pixels. Many object detection algorithms assume that the pedestrian scale is fixed during detection, such as the DPM detector. However, detectors often give rise to different detection effects under the circumstance of different scales. If a detector is used to perform pedestrian detection in different scales, the accuracy of pedestrian detection could be improved. A multi-resolution DPM pedestrian detection algorithm is proposed in this paper. During the stage of model training, a resolution factor is added to a set of hidden variables of a latent SVM model. Then, in the stage of detection, a standard DPM model is used for the high resolution objects and a rigid template is adopted in case of the low resolution objects. In our experiments, we find that in case of low resolution objects the detection accuracy of a standard DPM model is lower than that of a rigid template. In Caltech, the omission ratio of a multi-resolution DPM detector is 52% with 1 false positive per image (1FPPI);and the omission ratio rises to 59% (1FPPI) as far as a standard DPM detector is concerned. In the large-scale sample set of Caltech, the omission ratios given by the multi-resolution and the standard DPM detectors are 18% (1FPPI) and 26% (1FPPI), respectively.

关键词： Deformable Part Model Pedestrian Detection multi-resolution Latent SVM

multi-HIERARCHICAL STRUCTURE AND JUMP OF TEMPERATUREFOR THE GLOBE, CHINA AND YUNNAN OVER THE PAST 100 YEARS

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Journal of Tropical Meteorology 1999年第1期5卷 106-112页

作者：尤卫红段旭邓自旺伍从斌

An analysis has been conducted of the multi-hierarchical structure and jump of temperature variation for the globe, China and Yunnan Province over the past 100 years using an auto-adaptive, multi-resolution data filter set up in You, Lin and Deng (1997). The result is shown below in three aspects. (l1 The variation of global temperature in this period is marked by warming on a large scale and can be divided into three stages of being cold (prior to 1919), warm (between 1920 and 1978) and warmer (since 1 979). Well-defined jumps are with the variation in correspondence with the hierarchical evolution on such scale, occurring in 1920 and 1979 when there is the most substantial jump towards warming. For the evolution on smaller scales, however, the variation has shown more of alternations of cold and warm temperatures. The preceding hierarchical structure and warming jump are added with new ones. (2) The trend in which temperature varies is much the same for China and the Yunnan Province, but it is not consistent with that globally, the largest difference being that a weak period of cold temperature in 1955 - 1978 across the globe was suspended in 1979 when it jumped to a significant warming,while a period of very cold temperature in 1955 - 1986 in China and Yunnan was not followed by warming in similar extent until 1987. (3) Though there are consistent hierarchical structure and jumping features throughout the year in Yunnan, significant changes with season are also present and the most striking difference is that temperature tends to vary consistently with China in winter and spring but with the globe in summer and fall.

关键词： auto-adaptive multi-resolution data filter hierarchical structure climatic jump

Online Test and Fault Diagnosis of Yarn Quality Using Wavelet Analysis and FFT

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Journal of Donghua University(English Edition) 2002年第2期19卷 99-102页

作者：洪锡军邱浩波李昱明李从心 Plastic Technology Dept. Shanghai Jiaotong Univ. 200030Shanghai

A new online system of monitoring yarn quality and fault diagnosis is presented. This system integrates the technologies of sensor, signal process, communication, network, computer, control, instrument structure and mass knowledge of experts. Comparing with conventional off-line yarn test, the new system can find the quality defects of yarn online in time and compensate for the lack of expert knowledge in manual analysis. It can save a lot of yarn wasted in off-line test and improve product quality. By using laser sensor to sample the diameter signal of yarn and doing wavelet analysis and FFT to extract fault characteristics, a set of reasoning mechanism is established to analyze yarn quality and locate the fault origination. The experimental results show that new system can do well in monitoring yarn quality online comparing with conventional off-line yarn test. It can test the quality of yarn in real-time with high efficiency and analyze the fault reason accurately. It is very useful to apply this new system to upgrade yarn quality in cotton textile industry at present.

关键词： Wavelet Transform, multi-resolution Analysis,FFT, Fault Diagnosis, Online Test

Real-time Virtual Cloth Wrinkle Simulation using Energy Minimization

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Real-time Virtual Cloth Wrinkle Simulation using Energy Mini...

绿色纺织，健康生活——第三届纺织生物工程及信息学国际会议

作者： Yu-Cai Ma, Hai-Ru Long Textile college of Donghua University, Shanghai, 201620, China

This paper presents a method for real-time virtual cloth wrinkle simulation based on energy minimization. The model adopts the idea of multi-resolution particle system and pseudo curve driven technique. When wrinkles are generated by deforming the given mesh surface according to the shape change of a governing pseudo curve on the surface, energy function is defined on the governing pseudo curve to indicate flexure properties relying on material properties. By minimizing the energy function, our approach offers the ability to mimic desirable and pleasing wrinkle shapes corresponding to the given material properties such as cloth .We then propagate the wrinkle shape of the governing pseudo curve on the given mesh surface in the influence region .The hierarchical method presented in this paper is used to reduce significantly the execution time of the minimization process. The final surface wrinkles interpolate the governing and are attenuated while they gradually move close to the boundary of influence region to achieve the smoothness. Consequently, this results in the real-time manipulation for complex wrinkles shapes with material properties. Our approach provides an efficient and useful interactive tool to model realistic wrinkles on non-rigid objects similar to cloth.

关键词： real-time wrinkle multi-resolution pseudo curve driven energy minimization

Image Fusion Using Compressed Sensing in Nonsubsampled Contourlet Transform Domain

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Image Fusion Using Compressed Sensing in Nonsubsampled Conto...

2013年中国智能自动化学术会议

作者： Fu Liu School of Information Science and Engineering Hunan International Economics University

Image fusion algorithm using compressed sensing theory in NonSubsampled Contourlet Transform(NSCT) domain is proposed,NSCT can provide better sparsity than wavelet transform in image *** the transform of NSCT,low-frequency coefficients of the image are preserved,only high-frequency coefficients are *** coefficients are calculated according to different fusion rules in low frequency and high frequency domain. In the reconstruction,OMP algorithm is used to recover the high-frequency coefficients and the image is reconstructed by inverse nonsubsampled contourlet *** with wavelet compressed sensing algorithms,simulation results demonstrate that the quality of reconstructed image can be greatly improved.

关键词： Nonsubsampled contourlet transform Image fusion multi-resolution Compressed sending

multiresolution Wavelet Analysis Based Volatility Character of High Frequency SIGNAL

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Multiresolution Wavelet Analysis Based Volatility Character ...

The Second Conference on Fuzzy Information & Engineering

作者： JUN LI School of Management, Tianjin University,Tianjin 300072, China QIFA XU School of Statistics, Shandong Institute of Business & Technology, Yantai 300072, China

The paper focuses on the second moment of high frequency signal. "Wavelet realized volatility" is proposed to describe the volatility of signal process in both time domain and frequency domain at the same time based on wavelet multi-resolution analysis through maximal overlap discrete wavelet transform, which betters original "realized volatility" in time domain. Contrary to traditional fractional integration autoregressive moving average (ARFIMA) model of time series, the ARFIMA model is established for "wavelet realized volatility" in the paper, which is used to reflect volatility character of the signal process. The empirical results show that long memories in second moment of signal process are different from each other at different scales.

关键词： wavelet multi-resolution volatility high frequency

New Long-Distance Medical-Diagnosis System Based on Wavelet Transforms

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New Long-Distance Medical-Diagnosis System Based on Wavelet ...

第三届国际仪器科学技术学术研讨会

作者： SUN Li-xin a WANG Mu-kun a GUO Kun-qi b aCollege of Measurement Technology & Communication Engineering Harbin Univ. of Science and Technology Harbin 150080 China bDepartment of Communication Engineering Harbin Institute of Technology

In order to enable high resolution pathology images to be transmitted at low coding bit rate over the net and displayed in their entirety on the computer screen as well as realize the progressive zoom

关键词： telemedicine wavelets image compression multi-resolution pyramid algorithm