基于CUDA的三维数据并行可视化   总被引：1，自引：0，他引：1  

徐赛花  张二华 《CT理论与应用研究》2011,20(1):47-54

科学计算可视化是发达国家20世纪80年代后期提出并发展起来的一个新的研究领域,它运用计算机图形学和图像处理技术,将三维数据转换为图形及图像在屏幕上显示出来并进行交互处理,主要包括面绘制和体绘制两种方法。光线投射算法是最经典的三维数据体绘制方法,图像质量较高,但计算时间较长,基于CUDA的编程技术利用GPU的多核并行运算功能可显著提高计算速度,实现大规模三维数据的实时可视化。  相似文献   

Identification of multi-scale corresponding object-set pairs between two polygon datasets with hierarchical co-clustering     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

In this paper, we propose a means of finding multi-scale corresponding object-set pairs between two polygon datasets by means of hierarchical co-clustering. This method converts the intersection-ratio-based similarities of two objects from two datasets, one from each dataset, into the objects’ proximity in a geometric space using a Laplacian-graph embedding technique. In this space, the method finds hierarchical object clusters by means of agglomerative hierarchical clustering and separates each cluster into object-set pairs according to the datasets to which the objects belong. These pairs are evaluated with a matching criterion to find geometrically corresponding object-set pairs. We applied the proposed method to the segmentation result of a composite image with 6 NDVI images and a forest inventory map. Regardless of the different origins of the datasets, the proposed method can find geometrically corresponding object-set pairs which represent hierarchical distinctive forest areas.  相似文献   

An enhanced MEMS-INS/GNSS integrated system with fault detection and exclusion capability for land vehicle navigation in urban areas   总被引：2，自引：2，他引：0  

Ling Yang  Yong Li  Youlong Wu  Chris Rizos 《GPS Solutions》2014,18(4):593-603

We describe an enhanced quality control algorithm for the MEMS-INS/GNSS integrated navigation system. It aims to maintain the system’s reliability and availability during global navigation satellite system (GNSS) partial and complete data loss and disturbance, and hence to improve the system’s performance in urban environments with signal obstructions, tunnels, bridges, and signal reflections. To reduce the inertial navigation system (INS) error during GNSS outages, the stochastic model of the integration Kalman filter (KF) is informed by Allan variance analysis and the application of a non-holonomic constraint. A KF with a fault detection and exclusion capability is applied in the loosely and tightly coupled integration modes to reduce the adverse influence of abnormal GNSS data. In order to evaluate the performance of the proposed navigation system, road tests have been conducted in an urban area and the system’s reliability and integrity is discussed. The results demonstrate the effectiveness of different algorithms for reducing the growth of INS error.  相似文献   

The density functional calculations on the structural and electronic properties of the endohedral fullerene dimer (N₂@C₆₀)₂     

高虹  朱卫华  唐春梅  耿芳芳  姚长达  徐云玲  邓开明 《海洋学报(英文版)》2010,29(11)

The generalised gradient approximation based on density functional theory is used to study the structural and electronic properties of the endohedral fullerene dimer (N₂@C₆₀)₂. Four N atoms sit at the cage centres in the form of two N_2 molecules. The density of states and Mulliken charge analysis explore that the energy levels from -6 to -10 eV are mainly influenced by the N₂ molecules.  相似文献   

Improving the wind and wave estimation of dual-frequency altimeter JASON1 in Typhoon Shanshan and considering the rain effects   总被引：2，自引：1，他引：1  

YANG Le  LIN Mingsen  ZOU Juhong  LI Zhenghu  PAN Delu 《海洋学报(英文版)》2008,27(5):49-62

Altimetry data have been widely used in various fiehts of oceanography, including the extreme weather events such as tropical cyclones, typhoons, and hurricanes. The performance of JASON1 in Typhoon Shanshan is assessed by examining the sensor geophysical data record and illustrates how the measured return waveform, significant wave height, and backscatter are all affected by various factors associated with the typhoon, with details by the rain are illustrated. The correction method to maintain accurate wave height and wind speed measurements in Typhoon Shanshan and the results are presented. Furthermore, the additional results of rain rate and typhoon eye diameter can be retrieved. Because of the lack of in-situ measurements of wind, wave, and rain rate at Typhoon Shanshan, results are compared with the forecasted typhoon data and a good agreement is found.  相似文献   

Reconstruction of incomplete satellite SST data sets based on EOF method   总被引：1，自引：0，他引：1  

DING Youzhuan  WEI Zhihui  MAO Zhihu  WANG Xiaofei  PAN Delu 《海洋学报(英文版)》2009,28(2):36-44

As for the satellite remote sensing data obtained by the visible and infrared bands inversion, the clouds coverage in the sky over the ocean often results in missing data of inversion products on a large scale, and thin clouds di?cult to be detected would cause the data of the inversion products to be abnormal. Alvera et al.(2005) proposed a method for the reconstruction of missing data based on an Empirical Orthogonal Functions (EOF) decomposition, but his method couldn’t process these images presenting ex...  相似文献   

Calcium adsorption at the rutile-water interface: a potentiometric study in NaCl media to 250°C     

《Geochimica et cosmochimica acta》1999,63(19-20):3087-3096

Calcium adsorption by rutile was studied potentiometrically from 25 to 250°C, at ionic strengths of 0.03 and 0.30 m in NaCl media, using two complementary experimental methodologies. In the first, net proton adsorption in the presence and absence of Ca²⁺ was monitored, and in the second, samples were periodically withdrawn during the course of a titration to determine Ca²⁺ adsorption directly. These experiments revealed that Ca²⁺adsorption systematically increased with temperature relative to the pH of zero net proton charge in NaCl media alone (pH_znpc(NaCl) – pH). That is, as temperature increased, Ca²⁺ adsorption commenced at progressively more positive pH_znpc(NaCl) – pH values. Increasing ionic strength from 0.03 to 0.30 m NaCl suppressed Ca²⁺ adsorption at all temperatures as a result of either increased competition from Na⁺ or greater complexation of Ca²⁺ by Cl⁻. Finally, there was no apparent trend in the proton stoichiometric ratios (moles H⁺ released / moles Ca²⁺ adsorbed) with increasing temperature. This suggests that the electrostatic and/or chemical processes involved in Ca²⁺ adsorption do not change greatly with increasing temperature. Favorable entropic effects, related to the increasing ease of releasing Ca²⁺ waters of hydration, are believed to be primarily responsible for the increase in adsorption with temperature.  相似文献   

MEMS固体化学微推进阵列的微冲量测试技术     

李创新  余协正  叶迎华  沈瑞琪  王成玲  朱莹 《海洋科学进展》2013,(4):572-576

为了评价MEMS(Micro Electro Mechanical Systems)固体化学微推进阵列的推进性能,对其单元微冲量的精确测试显得尤为重要。在传统冲击摆的基础上,考虑微推进器推力和燃气射流冲击力之间的比例关系,设计了一套适用于MEMS固体化学微推进阵列单元微冲量的间接测试装置,并成功用于6×6规格(单元集成度为36个/cm²)微推进阵列的实际测试中。结果表明:典型实验数据下的待测微冲量为2.5442×10-4Ns,相对误差小于5%;实测8个单元的微冲量平均值为2.5574×10-4 N·s,相对偏差较小,具有很好的重复性。   相似文献   

Suppression of Flow Separation Around A Circular Cylinder by Utilizing Lorentz Force   总被引：2，自引：0，他引：2  

张辉  范宝春  陈志华  周本谋 《中国海洋工程》2008,22(1):87-95

Both experimental and numerical investigations on the flow past a cylinder under the influence of Lorentz force （electromagnetic force） were conducted in an electrically low-conducting fluid. The Lorentz force is applied beth locally, wholly and periodically on the surface of the cylinder, and their control effects for flow ,separation were investigated Both experimental and numerical results show that Lorentz force can suppress the flow separation with Lorentz force applied on beth local and whole surface of the cylinder. However, when the periodic and opposite Lorentz force adopted, the cylinder wake cannot be stabilized.  相似文献   

南京地区气溶胶谱分布的湿度相关性分析和等效复折射率预测          下载免费PDF全文

何晓宇  任登凤  程永强  束瑾  方明杰  刘璐 《气象科学》2023,43(6):772-780

通过实验收集大气颗粒物，对南京地区大气气溶胶谱分布进行了描述，对气溶胶分布与相对湿度的相关性进行了探讨。建立了南京地区7—11月气溶胶化学组分的月平均模型，得出气溶胶等效复折射率的预测方法。结果表明：南京地区的大气气溶胶颗粒物，峰值粒径在80~100 nm范围，属于典型的城市型气溶胶。数浓度与相对湿度的相关性与季节和粒径大小有关，在6—9月，相对湿度与细粒子数浓度呈负相关，与粗粒子呈正相关，在10—11月相反，且易受极端天气影响。建立的干气溶胶等效复折射率月平均模型，结合湿度修正模型得到某一日的复折射率，与AERONET站点数据进行了对比，结果较为一致，误差范围在0~0.03。  相似文献