增加黄金储备规避外汇风险

近几年，我国外汇储备逐年增加，而美元汇率偏弱，使我国承担很大的外汇风险。为了规避外汇风险，应增加黄金储备。文中提出了我国增加黄金储备总量的理由以及增加黄金储备的途径。这些建议具有可操作性，可以提供给有关部门参考。     

Analysis of dinosaur samples by nuclear microscopy

Several dinosaur bone and eggshell fossil samples unearthed at different sites in China were analyzed by means of nuclear microscopy. Concentrations and distributions of elements such as Na, Mg, Al, P, S, Ca, Cr, Mn, Fe, Cu, Zn, As, Br, Sr, Y, Ce, Pb and U, etc. were obtained for each sample. The results of quantitative PIXE and RBS analyses show unusually high concentrations of U and Ce in several samples obtained from a period near the K-T boundary (between Cretaceous and Tertiary periods, 65 million years ago), suggesting that some form of environmental pollution could be the cause of dinosaur extinction.     

我国车用无铅汽油的质量状况及分析

对1998－2001年间生产领域和流通领域的近500批次汽油产品检验数据进行了总结和分析，表明我国汽油的实物质量正在不断提高，但从环保要求出发还需不断向国际水平靠扰，尤其应进一步降低烯烃含量，硫含量。     

自适应的有效非局部图像滤波

研究了基于预选择的非局部均值滤波方法,并指出已有方法在提取图像子块特征方面的不足,利用梯度域奇异值分解(SVD) 提出一种自适应的有效非局部滤波方法。该方法对基于预选择的非局部滤波方法的贡献主要有:1)是一种基于图像子块结构特征的鲁棒预选择方法;2)研究了相似集大小与滤波性能的关系;3)相似子块的自动选取;4)提出一种局部自适应的滤波参数选取方法,根据图像局部内容的不同确定滤波参数。此外,利用欧氏距离的对称性进一步提高运行速度。实验结果表明:本文方法滤波后的图像在主客观方面都优于原算法和其他快速方法,且运行速度较快,是一种有效的滤波方法。     

α黄铜选择性溶解的研究

采用恒电流E-t曲线与旋转盘环电极方法研究了α黄铜(Cu32Zn)在酸性Na2SO4和HNO3稀溶液中的阳极溶解行为,得到的典型E-t曲线上存在几个特征区,证明在较低电流密度条件下的初始阶段只存在Zn的选择性溶解。用恒电位法研究了Cu32Zn选择性溶解过程,得到了按抛物线衰减的暂态扩散曲线,由i-t-1/2直线关系求得了不同介质中Cu32Zn中Zn的固相扩散系数D在10-16～10-13cm2·s-1数量级,发现中性介质中测出的D值比酸性介质中要大两个数量级。     

Multi-scale patch-based sparse appearance model for robust object tracking

When objects undergo large pose change, illumination variation or partial occlusion, most existing visual tracking algorithms tend to drift away from targets and even fail to track them. To address the issue, in this paper we propose a multi-scale patch-based appearance model with sparse representation and provide an efficient scheme involving the collaboration between multi-scale patches encoded by sparse coefficients. The key idea of our method is to model the appearance of an object by different scale patches, which are represented by sparse coefficients with different scale dictionaries. The model exploits both partial and spatial information of targets based on multi-scale patches. Afterwards, a similarity score of one candidate target is input into a particle filter framework to estimate the target state sequentially over time in visual tracking. Additionally, to decrease the visual drift caused by frequently updating model, we present a novel two-step object tracking method which exploits both the ground truth information of the target labeled in the first frame and the target obtained online with the multi-scale patch information. Experiments on some publicly available benchmarks of video sequences showed that the similarity involving complementary information can locate targets more accurately and the proposed tracker is more robust and effective than others.     

基于插值细分的逼近细分法

通过在Hassan的四点三重插值细分法中引入一个偏移变量,推导出了一种逼近细分法,从而使三重逼近细分和插值细分统一到一个细分格式.该方法利用细分格式的生成多项式,在理论上分析了提出的细分格式的一致收敛性和Ck连续性;通过对细分格式中参数u取不同的值,可对生成的极限曲线形状进行控制.数值实验结果表明,文中方法是合理有效的.     

Perceptual-saliency extremum lines for 3D shape illustration

Owing to their efficiency for conveying perceptual information of the underlying shape and their pleasing perceiving in visual aesthetics experience, line drawings are now becoming a widely used technique for illustrating 3D shapes. Using a center-surrounding bilateral filter operator on Gaussian-weighted average of local projection height between mesh vertices and their neighbors, a new perceptual-saliency measure which can depict surface salient features, is proposed in this paper. Due to the definition of perceptual-saliency measure, our perceptual-saliency extremum lines can be considered as the ridge-valley lines of perceptual-saliency measure along the principal curvature directions on triangular meshes. The experimental results demonstrate that these extremum lines effectively capture and depict 3D shape information visually, especially for archaeological artifacts.     

Packet-based Hierarchal Soft Shadow Mapping

Recent soft shadow mapping techniques based on back-projection can render high quality soft shadows in real time. However, real time high quality rendering of large penumbrae is still challenging, especially when multilayer shadow maps are used to reduce single light sample silhouette artifact. In this paper, we present an efficient algorithm to attack this problem. We first present a GPU-friendly packet-based approach rendering a packet of neighboring pixels together to amortize the cost of computing visibility factors. Then, we propose a hierarchical technique to quickly locate the contour edges, further reducing the computation cost. At last, we suggest a multi-view shadow map approach to reduce the single light sample artifact. We also demonstrate its higher image quality and higher efficiency compared to the existing depth peeling approaches.     

Robust object tracking via multi-scale patch based sparse coding histogram

There are many visual tracking algorithms that are based on sparse representation appearance model. Most of them are modeled by local patches with fixed patch scale, which make trackers less effective when objects undergone appearance changes such as illumination variation, pose change or partial occlusion. To solve the problem, a novel appearance representation model is proposed via multi-scale patch based sparse coding histogram for robust visual tracking. In this paper, the appearance of an object is modeled by different scale patches, which are represented by sparse coding histogram with different scale dictionaries. Then a similarity measure is applied to the calculation of the distance between the sparse coding histograms of target candidate and target template. Finally, the similarity score of the target candidate is passed to a particle filter to estimate the target state sequentially in the tracking process. Additionally, in order to decrease the visual drift caused by partial occlusion, an occlusion handling strategy is adopted, which takes the spatial information of multi-scale patches and occlusion into account. Based on the experimental results on some benchmarks of video sequences, our tracker outperforms state-of-the-art tracking methods.