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Accelerating the discontinuous Galerkin method for seismic wave propagation simulations using multiple GPUs with CUDA and MPI

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Earthquake Science 2013年第6期26卷 377-393页

作者： Dawei Mu Po Chen Liqiang Wang Department of Geology and Geophysics University of Wyoming Computer Science Department University of Wyoming

We have successfully ported an arbitrary highorder discontinuous Galerkin method for solving the threedimensional isotropic elastic wave equation on unstructured tetrahedral meshes to multiple Graphic Processing Units （GPUs） using the Compute Unified Device Architecture （CUDA） of NVIDIA and Message Passing Interface （MPI） and obtained a speedup factor of about 28.3 for the single-precision version of our codes and a speedup factor of about 14.9 for the double-precision version. The GPU used in the comparisons is NVIDIA Tesla C2070 Fermi, and the CPU used is Intel Xeon W5660. To effectively overlap inter-process communication with computation, we separate the elements on each subdomain into inner and outer elements and complete the computation on outer elements and fill the MPI buffer first. While the MPI messages travel across the network, the GPU performs computation on inner elements, and all other calculations that do not use information of outer elements from neighboring subdomains. A significant portion of the speedup also comes from a customized matrix-matrix multiplication kernel, which is used extensively throughout our program. Preliminary performance analysis on our parallel GPU codes shows favorable strong and weak scalabilities.

关键词： Seismic wave propagation DiscontinuousGalerkin method GPU

Short-term effects of fire disturbance on CH4 emission from forested wetlands in the Xiaoxing’an Mountains, Northeast China

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Journal of Forestry Research 2019年第3期30卷 969-979页

作者： Han Gu Wenyu Zheng dawei Xu Changcheng mu College of Architecture and Urban Planning Chongqing Jiaotong UniversityChongqing 40074People’s Republic of China Postdoctoral Program of Landscape Architecture Northeast Forestry UniversityHarbin 150040People’s Republic of China School of Forestry Northeast Forestry University Harbin 150040People’s Republic of China

Using static chamber gas chromatography, we determined the seasonal dynamics, controlling factors, and distribution patterns of forest swamp CH4 levels and related environmental factors (temperature, water level) after fire disturbance in the Xiaoxing’an Mountains. The results showed the following: during the growing season, the annual CH4 emission distribution ranged from - 0.001 ± 0.012 to 22.373 ± 3.650 mg m^-2 h^-1;mild fire caused the swamp CH4 emission flux of tussock, shrub, Alnus sibirica and birch swamp to increase by 56.0–524.7%;at low water levels, temperature had a significant influence on the swamp type, and the correlation between the methane emission flux and temperature was significantly strengthened;after a fire disturbance, methane emissions from all types of marsh were highest in summer and second highest in autumn, with a weak absorption in spring;and along the water environment gradient of the transition zone, the CH4 emission flux presented a decreasing trend in its spatial distribution pattern.

关键词： Xiaoxing’an Mountains Forest swamp CH4 emission Fire disturbance

The Hemodynamic Study on the Effects of Entry Tear and Coverage in Aortic Dissection

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医用生物力学 2019年第A1期34卷 87-88页

作者： Zhenxia mu Xiaofei Xue Minrui Fu dawei Zhao Bin Gao Yu Chang College of Life Science and Bioengineering Beijing University of Technology

Nowadays,cardiovascular disease has gradually become the number one killer of human health.The Stanford type-A aortic dissection is a relatively common cardiovascular disease with potential hazards.The disease is caused by a partialtearing of the aortic intima.Thoracic endovascular aortic repair(TEVAR)is one of the most effective treatment for type A aortic dissection and has been widely used clinically to achieve thrombosis and reduce pressure by covering the incision tear in the FL.However,the effect of entry tear location on type-A aortic dissection and the prognosis of TEVAR intervention are unclear.In this work,the hemodynamic effects of the type-A aortic dissection in different entry and covering entry tear position were mainly studied.It can provide a new method or idea in the field of the aortic dissection hemodynamics,which is of great significance to provide a basic theoretical research on the development of aortic dissection in the aspect of clinical judgment.Two type-A aortic dissection models with different entry tear positions(Model 1:the entry tear was located at the entrance of the ascending aorta,Model 2:the entry tear was located at the starting position of the descending aorta)were reconstructed according to the computed tomography(CT)images of the patients.In our study,the thoracic aortic endovascular repair was simulated by covering the entry tear(Model 3).Then,the semi-automatic adaptive technology HyperMeshl0.0(Altair HyperWorks,Troy,Ml,USA)mesh generator was used to generate the high-quality tetrahedral 3D mesh.To clarify the hemodynamic effects of entry tear and coverage in aortic blood flow pattern,the comparative study on the true lumen(TL)and false lumen(FL)blood flow patterns of three models were carried out numerically(the time-dependent pulsatile waveform of pressure boundary conditions used at the aortic inlet were consistent with Rapezzis’s work,time-dependent pulsatile waveform of velocity at the descending aorta outlet and the time-dependent pulsatile waveform of pressure at the

关键词： computational fluid dynamics(CFD) aortic dissection hemodynamic TEVAR

Visual target tracking based on multi-view feature fusion with online multiple instance learning

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Visual target tracking based on multi-view feature fusion wi...

基于Hu不变矩和BP神经网络的木材缺陷检测

第36届中国控制会议

作者： Weixin Hua Dejun mu dawei Guo Hang Liu School of Automation Northwestern Polytechnical University Company of Shaanxi China Mobile Limited

ISBN: (纸本)9781538629185

The tracking methods under the online multiple instance learning（MIL） framework always use single channel’s information or transform the RGB image to gray image for color video tracking,which may cause the information loss of the color image.In addition,the MIL tracker only use the haar-like feature to construct the target appearance and ignore the different samples have different importance to the tracking results,which is argued to susceptible to interference with complex background.Therefore,this paper presents an online visual target tracking method based on multi-view feature fusion with joint online multiple instances learning to overcome the disadvantages of the MIL tracker.Firstly,we extract the color histogram feature and haar-like features to construct the two type classifiers.Secondly,we compute the bag probability by summing the instance probability in the process of updating the classifiers and construct the strong classifiers.Finally,the object location is achieved by fusing the two type strong classifiers.The experimental results show that the proposed method performs better than several other tracking methods like IVT,MIL,OAB and WMIL trackers with smaller central position error on challenging color video sequences.

关键词： target tracking multi-view feature fusion multiple instance learning bag probability classifier

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东南大学学报（自然科学版） 2013年第A01期43卷 63-66页

作者：戚大伟牟洪波东北林业大学理学院哈尔滨150040

采用X射线作为检测手段,对木材进行无损检测,通过检测透过木材的射线强度来断定检测木材是否存在缺陷.对得到的木材缺陷进行图像处理,将木材缺陷图像转化为灰度图像,再把灰度图像转换为二值图像.根据经验选择相应的阈值,提取出清晰的木... 详细信息

采用X射线作为检测手段,对木材进行无损检测,通过检测透过木材的射线强度来断定检测木材是否存在缺陷.对得到的木材缺陷进行图像处理,将木材缺陷图像转化为灰度图像,再把灰度图像转换为二值图像.根据经验选择相应的阈值,提取出清晰的木材缺陷边缘,把木材缺陷部位从背景中分离出来,完成木材缺陷图像分割.对Hu提出的区域不变矩进行扩展,得到一组新的描述形状特征的参数,这些参数具有平移、缩放和旋转不变性,并且具有较低的计算复杂性.将这些特征参数预处理后输入BP神经网络,对木材缺陷进行检测,检测准确率达到86%以上,试验结果表明此方法的可行性,为实现木材缺陷的自动检测提供了新的途径.

关键词： Hu不变矩 BP神经网络图像处理检测

The Hemodynamic Study on the Effects of Entry Tear and Coverage in Aortic Dissection

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Computer Modeling in Engineering & Sciences 2019年第12期121卷 929-945页

作者： Zhenxia mu Xiaofei Xue Minrui Fu dawei Zhao Bin Gao Yu Chang School of Life Science and BioEngineering Beijing University of TechnologyBeijing100124China

In this work,the hemodynamic effects of the type-A aortic dissection in different entry and covering entry tear positions were mainly studied.It provides a new method or idea in the field of the aortic dissection hemodynamics,and it is of profound significance to provide basic theoretical research on the development of aortic dissection in the aspect of clinical judgment.Two type-A aortic dissection models with different entry tear positions(Model 1:The entry tear was located at the entrance of the ascending aorta,Model 2:The entry tear was located at the starting position of the descending aorta)were reconstructed according to the computed tomography(CT)images of the patients.In our study,the thoracic aortic endovascular repair was simulated by covering the entry tear(Model 3).To clarify the hemodynamic effects of entry tear and coverage,the comparative study on the true lumen(TL)and false lumen(FL)blood flow patterns of three models were carried out numerically.The velocity vector,flow ratio,pressure,time-averaged wall shear stress(TAWSS)and relative residence time(RRT)were calculated to evaluate the hemodynamic changes.The results of this work indicated that(I)the velocity of entry tear at the aorta entrance was higher;(II)The helical development of the TL and FL might be related to the helical nature of aortic arch;(III)The blood flow which passing the FL of Model 1,Model 2 and Model 3 in one cardiac cycle were approximately 26.63%,13.39%and 1%,respectively;(IV)The difference in intima wall pressure of the TL and FL were showed a strong pulsation;(V)The TAWSS distribution in TL and FL were completely different(the TAWSS in TL intima>8 Pa,the TAWSS in FL intimamulti-dimensional hemodynamic information such as velocity field,pressure,TAWSS and RRT,which can help clinicians better understand the development of type-A

关键词： Computational fluid dynamics(CFD) aortic dissection hemodynamic TEVAR

Synergistic Catalytic Effect of LaMnO3-CNTs in Oxygen Reduction Reaction

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Synergistic Catalytic Effect of LaMnO3-CNTs in Oxygen Reduct...

2021中国汽车工程学会年会暨展览会

作者： Chen Yunzhi mu Yangchang Liu Fude Peng Chenyang Xie Tianfeng Zheng dawei Shi Zhicong Yang Yibin School of Materials and Energy Guangdong University of Technology

The application of perovskite oxides with ABO structure to oxygen reduction reaction(ORR) catalysts(ORRCs) has received increasing attention.Most of the studies have focused on changing the A or B metal ions in the structure.However,the best catalyst carrier of ABO remains unidentified.Therefore,in the present work,LaMnO-CNTs,LaMnO-graphene,LaMnO-graphene oxide,and LaMnO-acetylene black were synthesized from a LaMnO precursor and various catalyst carriers with different structures.The results revealed that LaMnO-CNTs,which are binary catalysts that act as LaMnO carriers and an electrochemically active ingredient,exert a considerable synergistic catalytic effect.A maximum power density of 265.8 mW cm was realized for the aluminum-air batteries using LaMnO-CNTs as ORRCs.

关键词： perovskite LaMnO3 CNTs Oxygen reduction reaction synergistic catalytic effect

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智能楼宇低压配电自动监控系统设计与开发

中国电力教育 2011年第12期 112-113页

作者：牟大为山东省潍坊市规划设计研究院建筑二室潍坊市远景建筑设计研究院

利用先进的嵌入控制器和低压电器设计了一套楼宇配电低压自动监控系统。该系统具有自动采集楼宇中低压配电(0.4kV)线路的电压、电流等信号,并可进行故障定位和故障检测等功能。详细介绍了系统设计方法、网络结构、界面和功能。

关键词：楼宇低压配电自动监控

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脱木素木材衍生功能材料研究进展

世界林业研究 2022年第3期35卷 50-55页

作者：杨鸿赵鹏炜牟洪波戚大伟东北林业大学理学院哈尔滨150040 东北林业大学工程技术学院哈尔滨150040

木材是一种可再生和机械坚固的天然生物基模板,半纤维素和木质素基质结合纤维素原纤维在木材中分层排列。因此在不改变纤维素原纤维分级排列的情况下去除木材细胞壁中的木质素,可为具有对齐纤维素结构的生物模板功能材料领域带来更多可... 详细信息

木材是一种可再生和机械坚固的天然生物基模板,半纤维素和木质素基质结合纤维素原纤维在木材中分层排列。因此在不改变纤维素原纤维分级排列的情况下去除木材细胞壁中的木质素,可为具有对齐纤维素结构的生物模板功能材料领域带来更多可能性。基于脱木素木材提供的生物模板,可开发出不同的功能材料,并广泛应用于不同领域。文中总结脱木素木材的主要制备方法和功能材料的开发策略,展望脱木素木材衍生功能材料的发展潜力和趋势,旨在为木材功能化研究提供新思路。

关键词：脱木素木材木材功能化木材改性