利用Open GL进行CAD的研究

叙述了当前CAD开发的概况，着重介绍了Open GL的特点、功 能以及OpenGL结合VC++进行CAD程序设计的步骤，且指出了开发过程中需要注意的一些问题 。     

Attributed hypergraph matching on a Riemannian manifold

If we consider a matching that preserves high-order relationships among points in the same set, we can int-roduce a hypergraph-matching technique to search for correspondence according to high-order feature values. While graph matching has been widely studied, there is limited research available regarding hypergraph matching. In this paper, we formulate hypergraph matching in terms of tensors. Then, we reduce the hypergraph matching to a bipartite matching problem that can be solved in polynomial time. We then extend this hypergraph matching to attributed hypergraph matching using a combination of different attributes with different orders. We perform analyses that demonstrate that this method is robust when handling noisy or missing data and can achieve inexact graph matching. To the best of our knowledge, while attributed graph-matching and hypergraph-matching have been heavily researched, methods for attributed hypergraph matching have not been proposed before.     

Sorting Stably,in Place,with O(n log n) Comparisons and O(n) Moves

We settle a long-standing open question, namely whether it is possible to sort a sequence of n elements stably (i.e., preserving the original relative order of the equal elements), using O(1) auxiliary space and performing O(n log n) comparisons and O(n) data moves. Munro and Raman stated this problem in J. Algorithms (13, 1992) and gave an in-place but unstable sorting algorithm that performs O(n) data moves and O(n^1+ε) comparisons. Subsequently (Algorithmica, 16, 1996) they presented a stable algorithm with these same bounds. Recently, Franceschini and Geffert (FOCS 2003) presented an unstable sorting algorithm that matches the asymptotic lower bounds on all computational resources.     

Recognizing Hand-Printed Digits with a Distance Quasi-Metric

A distance quasi-metric for pattern recognition is presented. The “quasi” modifier distinguishes the metric from “true” distance metrics which obey a set of standard constraints. By relaxing one of the constraints and coupling it with a fast multidimensional search technique, the metric demonstrates improved accuracy and efficiency compared to other metrics in recognizing hand-written digit samples. A high-level design of a fast optical comparator for computing the distance in O( ) is also presented.     

基于距离负相关性的轨迹相似性度量方法

With the development of wireless communication technology and positioning technology, trajectory data emerge in large quantities. Similarity measurement is used in the query and analysis of trajectory data. In this paper, an improved similarity measure- ment is proposed. By introducing the negative correlation between the distance of points and the similarity into the real sequence ed- iting distance, the robustness to noise is preserved and the sensitivity to difference is improved. We apply different similarity mea- sures to the trajectory privacy protection method based on cluster-reconstruction, and verify the effectiveness of the proposed trajec- tory similarity measure by experiment on the real data and the synthetic data.     

基于黎曼流形稀疏编码的图像检索算法

针对视觉词袋（Bag-of-visual-words,BOVW）模型直方图量化误差大的缺点,提出基于稀疏编码的图像检索算法.由于大多数图像特征属于非线性流形结构,传统稀疏编码使用向量空间对其度量必然导致不准确的稀疏表示.考虑到图像特征空间的流形结构,选择对称正定矩阵作为特征描述子,构建黎曼流形空间.利用核技术将黎曼流形结构映射到再生核希尔伯特空间,非线性流形转换为线性稀疏编码,获得图像更准确的稀疏表示.实验在Corel1000和Caltech101两个数据集上进行,与已有的图像检索算法对比,提出的图像检索算法不仅提高了检索准确率,而且获得了更好的检索性能.     

A nonparametric Riemannian framework on tensor field with application to foreground segmentation

Background modeling on tensor field has recently been proposed for foreground detection tasks. Taking into account the Riemannian structure of the tensor manifold, recent research has focused on developing parametric methods on the tensor domain, e.g. mixture of Gaussians (GMM). However, in some scenarios, simple parametric models do not accurately explain the physical processes. Kernel density estimators (KDEs) have been successful to model, on Euclidean sample spaces, the nonparametric nature of complex, time varying, and non-static backgrounds. Founded on a mathematically rigorous KDE paradigm on general Riemannian manifolds recently proposed in the literature, we define a KDE specifically to operate on the tensor manifold in order to nonparametrically reformulate the existing tensor-based algorithms. We present a mathematically sound framework for nonparametric modeling on tensor field to foreground detection. We endow the tensor manifold with two well-founded Riemannian metrics, i.e. Affine-Invariant and Log-Euclidean. Theoretical aspects are presented and the metrics are compared experimentally. By inducing a space with a null curvature, the Log-Euclidean metric considerably simplifies the scheme, from a practical point of view, while maintaining the mathematical soundness and the excellent segmentation performance. Theoretic analysis and experimental results demonstrate the promise and effectiveness of this framework.     

Diffusion tensor interpolation profile control using non-uniform motion on a Riemannian geodesic

Tensor interpolation is a key step in the processing algorithms of diffusion tensor imaging (DTI), such as registration and tractography. The diffusion tensor (DT) in biological tissues is assumed to be positive definite. However, the tensor interpolations in most clinical applications have used a Euclidian scheme that does not take this assumption into account. Several Rie-mannian schemes were developed to overcome this limitation. Although each of the Riemannian schemes uses different metrics, they all result in a ‘fixed’ interpolation profile that cannot adapt to a variety of diffusion patterns in biological tissues. In this paper, we propose a DT interpolation scheme to control the interpolation profile, and explore its feasibility in clinical applications. The profile controllability comes from the non-uniform motion of interpolation on the Riemannian geodesic. The interpolation experiment with medical DTI data shows that the profile control improves the interpolation quality by assessing the reconstruction errors with the determinant error, Euclidean norm, and Riemannian norm.     

基于离散对数的数字签名的(t,n)验证

随着计算机和网络通信技术的发展,数字签名技术得到了广泛的应用。该文以数字签名方案DSA以及双变量单向函数为基础,提出了数字签名的（t,n）验证方案。它没有Ham方案[4]中容易伪造签名的问题。它的计算量也比原方案小。     

基于SOA的信息距离研究

信息是物体运动状态的表征,而信息必须选择某一事物作为“载体”,利用应用程序的不同功能单元（称为服务）来作为信息的载体,通过信息在转移中遇到的阻碍越小,信息距离越短这种原理,来定义并且描述信息距离,详细的信息距离为后面服务调用时的路径选择起到了至关重要的作用。     

一个（t，n）门限签名-（k，m）门限验证的群签名方案

基于离散对数问题,提出了一个(t,n)门限签名-(k,m)门限验证的群签名方案。在该方案中,n个签名者中至少t个合作可以生成有效的群签名;而m个验证者中至少k个合作可以验证签名的有效性。参与者的公、私钥以及群公钥由参与者共同协商,无需可信中心参与;参与者之间的信息可以以明文形式传送;能够抵御内部相互欺诈和外部攻击。方案的安全性是基于离散对数问题的难解性。     

A novel (n,t, n) secret image sharing scheme without a trusted third party

Secret image sharing is a technique to share a secret image among a set of n participants. A trusted third party embeds the secret image into the cover image to generate shadow images such that at least t or more shadow images can reconstruct the secret image. In this paper, we consider an extreme and real-world situation, in which there is no one who is trusted by anyone else. In the proposed scheme, the participants can act as a dealer and communicate with each other in a secret channel. Each participant can generate her/his own shadow image independently, according to the cover image and the secret image. Experimental results are provided to show that the shadow images have satisfactory quality. In addition, our scheme has a large embedding capacity, and the secret image can be reconstructed losslessly.     

互联网络RCP(n)的路由算法

在对互联网络RCP（Ringed Crossed cube Petersen）拓扑结构研究的基础上,利用RCP（n）网络具有正则性,良好的可扩展性,以及具有比Q_n、HP（n）、RHP（n）网络更短的直径和更小的构造开销这些特性,给出了RCP（n）的单播路由算法和广播路由算法,并证明了RCP（n）比Q_n、HP（n）、RHP（n）网络具有更好的路由性能。     

A new hardware-assisted PIR with O(n) shuffle cost

Since the concept of private information retrieval (PIR) was first formalized by Chor et al., various constructions have been proposed with a common goal of reducing communication complexity. Unfortunately, none of them is suitable for practical settings mainly due to the prohibitively high cost for either communications or computations. The booming of the Internet and its applications, especially, the recent trend in outsourcing databases, fuels the research on practical PIR schemes. In this paper, we propose a hardware-assisted PIR scheme with a novel shuffle algorithm. Our PIR construction entails O(n) offline computation cost, and constant online operations and O(log n) communication cost, where n is the database size.     

具有O(n)消息复杂度的协调检查点设置算法

协调检查点设置及回卷恢复技术作为一种有效的容错手段,已广泛地运用在集群等并行/分布计算机系统中.为了进一步降低协调检查点设置的时间和空间开销,提出了一种基于消息计数的协调检查点设置算法.该算法无须对底层消息通道的FIFO特性进行假设,并使同步阶段引入的控制消息复杂度由通常的O(n2)降低到O(n),有效地提高了系统的效率和扩展性.