基于移动多核GPU的并行二维DCT变换实现方法

传统的基于CPU的串行程序所实现的二维DCT变换算法时间复杂度高变换效率低,难以满足许多应用的实时要求.特别是在当代以嵌入式处理器为核心的移动端信息处理终端,有限的CPU性能更加难以实现快速的DCT变换.值得欣慰的是新一代嵌入式处理器提供了支持GPGPU技术的GPU,为解决复杂的移动计算问题提供了高效的并行化解决途径.基于最新的ARM Cortex-A15内嵌GPU Mali-T604及OpenCL框架设计实现了一种针对二维DCT变换的并行化加速方案并实测了优化效果,实验结果表明文中的并行方案能够提高二维DCT变换的效率,在输人数据量足够大的条件下能够达到近20倍的加速比.     

基于GPU的HASM动态模拟与实时渲染方法

 基于微分几何曲面论的高精度曲面模拟(high accuracy surface modeling, HASM)需要大量的复杂密集计算,在CPU上模拟极为耗时,使得在现有的硬件条件下,实时动态模拟曲面并实时可视化极具挑战性。论文提出了GPU加速的HASM方法,充分利用现代显示适配器(graphic processor unit, GPU)技术,运用GPU最新发展起来的并行计算能力,使用并行化的预处理共轭梯度方法解算曲面,完成曲面模拟,并同时利用GPU的高速缓存架构,对渲染操作进行充分优化,以实现高效实时可视化。HASM需要的有限差分离散和高速解算操作,均充分利用现代GPU架构,所具有的多处理器和众多的流处理器所产生的强大并行计算能力,可视化也用GPU高速缓存技术和三角条带方法进行充分优化。数值实验和实际项目区高程模拟实验均表明, 在GPU为NVIDIA quadro 2000和CPU为DualCore Intel Core 2 Duo E8400的硬件配置下,GPU并行化的曲面模拟方法比普通方法速度提高了约10倍,使得动态模拟与可视化算法可以达到交互式的帧速及实时可视化的要求。     

多边形叠加Vatti算法的VCS优化方法与GPU并行化

Vatti算法是常用的矢量多边形裁剪算法之一,在其构建扫描束实现交点计算的过程中,二叉树的数据结构和递归计算方法导致其计算效率受矢量多边形边界顶点数量影响显著。本文针对Vatti算法执行过程中较为耗时的扫描束构建环节,提出了一种多边形边界顶点预排序的优化方法——VCS（Vertex Coordinate Pre-Sorting）方法,并基于该方法实现了对Vatti算法的GPU细粒度并行化。VCS方法使用双向链表对Vatti算法原有的二叉树数据结构进行了替换,以较小的额外存储空间取得了多边形边界顶点信息查找效率的明显提升。在GPU环境下采用双调排序算法对多边形边界顶点数组元素进行并行化排序并过滤出有效值,克服了原始算法使用二叉树存储导致效率低下的问题。实验结果表明,改进后的算法与原始算法相比,具有相同的计算精度;当多边形顶点数量为92万,CUDA每个线程块中的线程数量为32时,使用VCS优化方法,与采用CPU计算构建扫描束方法相比,GPU并行化方法获得了39.6倍的相对加速比,矢量多边形叠加分析算法效率总体上提升了4.9倍。     

基于GPU并行加速的叠前逆时偏移方法

为了提高复杂地下介质的成像精度和偏移算法的计算效率,提出可高效对地下复杂构造进行准确成像的GPU加速叠前逆时偏移方法.该方法采用双程声波方程进行波场延拓,突破倾角限制,借助于高阶有限差分方法实现叠前逆时偏移成像;利用GPU(Graphic Processing Unit)并行加速技术对波场延拓和成像进行计算,相比于传统算法,其计算效率有较大提高,可以解决叠前逆时偏移算法计算量过大问题;在获取波场信息过程中,也采用随机边界条件,实施以计算换存储策略,解决逆时偏移计算中的海量存储问题.模型测试结果表明,该方法能够高效和高精度地对地下复杂地质体成像.     

基于GPU的S63标准电子海图数据解密算法

S63标准采用Blowfish算法对原始海图数据加密后发行,数据的解密成为电子海图系统数据转换和更新中一个耗时的过程。为提高数据处理的速度,针对Blowfish分组密码算法的特点,提出一种利用图形处理器(GPU)的海图并行解密算法,并采用数据传输和处理的同步技术进行了优化。测试表明,采用GPU的并行解密算法是纯CPU串行处理的9.8倍。该算法不仅可大大加快海图数据转换和更新过程,对地理信息系统海量数据处理也有一定的借鉴价值。     

基于CUDA的IDW并行算法及其实验分析

近些年来,空间数据获取技术得到了迅猛的提高,例如LIDAR,通常可以产生成千上万个点,这对计算机的处理能力提出了挑战.最近,图形处理器(GPU)的计算能力得到了巨大的提升,致使GPU的通用计算引起了关注.GPU是流处理器的集合,最近的设备的流处理器超过240个,浮点峰值比CPU快10多倍.在GPU上编程和编译的环境称计...     

Retinex图像增强在GPU平台上的实现

伴随着无人机时代的到来,对海量数据处理的实时性要求越来越高。本文在GPU（Graphic Processing Unit）平台上实现了Retinex图像增强算法的并行处理,提升了Retinex图像增强算法处理高分辨率数字图像的处理速度。首先,通过数据合并访问和内存数据交互技术实现了数据的快速访问,缩短了数据在不同种类内存间的传输时间,提升了数据访问的效率;然后,采用内核指令优化和数据并行计算技术,实现了Retinex图像增强算法在GPU平台上的多核程序设计;最后,采用主机端和设备端的异步执行模式,在数据传输的同时进行内核数据的并行计算,通过任务级的并行进一步缩短了算法在GPU平台上的执行时间。研究表明,对于不同分辨率的图像,Retinex图像增强算法的处理速度相比于CPU平台均有数十倍的提高,如处理一帧分辨率为2048像元×2048像元的图像仅需要38.04 ms,算法的处理速度较CPU提高了40倍。     

基于GPU的全球地形数据加速绘制技术研究

在对基于GPU大规模地形数据快速绘制方法的研究基础上,针对GPU的批量绘制的特点,提出了改进的几何体实例化方法,把它用在全球格网的快速绘制上。把地形数据通过重新编码存储在高度图中,再结合Shader Model 3.0引入的顶点纹理拾取技术,在GPU中进行解码,得到原始的DEM数据,避免了在CPU上执行顶点缓存的更新。实验证明该算法充分利用了新一代GPU的特性,降低了CPU的负担,能达到实时绘制的要求。     

基于可编程图形硬件的体绘制技术

三维数据场可视化中的体绘制技术是科学计算可视化领域最重要的一项技术。由于体绘制技术需要处理的数据量十分庞大,生成图像算法又比较复杂,常常需要使用高端图形工作站和特殊硬件来实现。近年来计算机性能的大幅提高,特别是可编程GPU的顶点和片段处理器的快速发展,为普通Pc机上实现实时体绘制技术提供了硬件加速的支持。介绍了科学计算可视化和可编程GPU的概况,在普通PC机上实现了基于GPU的三维纹理映射的体绘制算法,实验表明,在不损失图像绘制质量的情况下,加快了绘制的速度。     

基于反泄漏Fourier变换的地震数据重建方法

应用反泄漏Fourier重建方法,对空间方向采样不规则的地震数据进行规则化重建,引入GPU加速算法,将非均匀Fourier变换部分转化为矩阵乘法形式,将矩阵乘法部分应用于GPU加速算法加速处理。理论模型与实际数据测试结果验证该方法的有效性及合理性。     

Preliminary study on plasma membrane fluidity of Psychrophilic Yeast Rhodotorula sp.NJ298 in low temperature

The ability of cell to modulate the fluidity of plasma membrane was crucial to the survival of microorganism at low temperature. Plasma membrane proteins, fatty acids and carotenoids profiles of Antarctic psychrophilc yeast Rhodotorula sp. NJ298 were investigated at -3 ℃, 0 ℃ and 8 ℃. The results showed that plasma membrane protein content was greater at -3 ℃ than that at 8 ℃, and a unique membrane polypeptide composition with an apparent molecular mass of 94.7 kDa was newly synthesized with SDS-PAGE analysis; GC analysis showed that the main changes of fatty acids were the percentage of unsaturated fatty acids (C18∶ 1 and C18∶ 2) and shorter chain saturated fatty acid (C10∶ 0) increased along with the decrease of the culture temperature from 8 ℃ to -3 ℃; HPLC analysis indicated that astaxanthin was the major functional carotenoids of the plasma membrane, percentage of which increased from 54.6±1.5% at 8 ℃ to 81.9±2.1% at -3 ℃. However the fluidity of plasma membrane which was determined by measuring fluorescence anisotropy was similar at -3 ℃, 0 ℃ and 8 ℃. Hence these changes in plasma membrane's characteristics were involved in the cellular cold-adaptation by which NJ298 could maintain normal plasma membrane fluidity at near-freezing temperature.     

Information for authors

正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprehensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose     

JOURNAL OF OCEAN UNIVERSITY OF CHINA

<正>Copyright Submfnion of a roanusatpt inks:that the work described has not been published before(exoept In the form of an abstrW or as part of a published lecture,review,or thesis);that it is not under consideration for publication elsewhere that its publication has been approved by ail     

Information for Authors

<正>The Journal of Ocean University of China(Oceanic and Coastal Sea Research)is a comprehensive academic quarterly sponsored by the Ocean University of China,published one volume per year.This journal is devoted to the publication of the theoretical and applied research results on oceanography and marine fisheries.The fieldcovered include the physical,chemical,biological,geo-     

Hydraulics and Hydrology in Mountain Areas

<正>The 35th IAHR World Congress was held in Chengdu,China from September 8 to September 132013.The title of the conference was:"The Wise Finds Pleasure in Water:Meandering through Water Science and Engineering".During the congress,1239 papers were presented in 139sessions for oral presentations and 7 sessions for poster presentations.After the Congress,a Committee was appointed to select some of the best papers presented at the Congress for publication,after a     

Sea ice thickness measurement in spring season in Bothnian Bay using an electromagnetic induction instrument

As an important component of the cryosphere,sea ice is very sensitive to the climate change.The study of the sea ice physics needs accurate sea ice thickness.This paper presents an electromagnetic-induction(EM) technique which can be used to measure the sea ice thickness distribution efficiently,and the successful application in Bothnian Bay.Based on the electromagnetic field theory and the electrical properties of sea ice and seawater,EM technique can detect the distance between the instrument and the ice/water interface accurately,than the sea ice thickness is obtained.Contrastive analysis of the apparent conductivity data obtained by EM and the value of drill-hole at same positions allows a construction of a transformable formula of the apparent conductivity to sea ice thickness.The verification of the sea ice thickness calculated by this formula indicates that EM technique is able to get reliable sea ice thickness with average relative error of only 12%.The statistic of all ice thickness profiles shows that the level ice distribution in Bothnian Bay was 0.4-0.6 m.     

Thermohaline structure inhomogeneity associated with polynia at the northern margin of Emery Ice-shelf

Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.     

Phylogenetic analysis of cultivable bacteria isolated from Arctic sea-ice

Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter.     

Information for authors

正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied