利用矩阵的奇异值分解对物体进行形状复原

奇异值分解法（singular value decomposition）是一种矩阵的分解方法,图像矩阵的奇异值（Singular Value）及其特征空间反映了图像中的不同成分和特征。奇异值分解（Singular Value Decomposition,SVD）是一种基于特征向量的矩阵变换方法。本文利用该方法利用某物体的数枚数字图像获得该物体的形状信息,也就是利用数字图像的灰度值来获得物体的法线向量矩阵。而且,利用具体的实验验证了该方法的可靠性。     

基于多特征融合和二维投影非负矩阵分解的图像检索

文章提出了一种基于非负矩阵分解(Nonnegative Matrix Factorization.NMF)和多特征融合的图像检索模型。通过提取图像的颜色和纹理特征,进行NMF分解,得到NMF的基矩阵和样本的系数矩阵。利用二维主成分分析(2DPCA)的思想对系数矩阵降维,然后通过特征加权的方法比较检索结果。文章使用500幅人物图像组成的图像库进行试验,该方法利用了图像的多个特征和2DPCA思想,使得文章中的方法提高了检索的查准率,而且检索速度优于非负矩阵分解和二维主成分分析。     

一种二值图像连通区域标记的简单快速算法

针对传统二值图像连通区域标记需要对图像进行两次扫描的缺点,提出了一钟新的二值图像连通区域标记算法。算法借助创建一与图像等大的标记矩阵,通过深度优先搜索算法对图像进行一次扫描后,将标记编号记录在标记矩阵中。此算法不受连通区域的形状和面积影响,表现出了良好的鲁棒性。最后通过OpenCV对该算法进行了实现并与传统标记算法进行了时间性能比较。     

空间相关性的统计分析

空间自相关统计量是用于度量地理数据的一个基本性质,空间分析学者结合日益成熟的电脑科技GIS、空间计量方法、以及大型资料库,目的在精确地界定空间因素的重要性及影响力,空间权重矩阵用fij符号来表示空间的对象i,j的互相关联,fij=0就是表示空间权重矩阵的对角元素为零。空间权重矩阵有可以根据文中的几个函数方法来确定。     

基于功能矩阵的战时装备维修保障任务分解方法研究

本研究应用功能树和布尔代数的方法对不同的任务分解形式加以表示,通过功能相似分解和功能矩阵约简等方法,实现维修保障任务-功能的分解。任务分解的案例表明,该方法可以简化任务分解过程,实现快速、有效地确定维修保障任务-功能分解。     

一种基于多小波变换的半脆弱数字水印算法

利用图像经CARDBAL多小波分解后,不同尺度、不同方向的分量能量平均分配于四个子图这一特点,通过调整这四个子图中系数的标准差来嵌入二值图像水印;提取水印后,通过比较提取水印与原始水印差异图局部与整体TAF值的差异来区别篡改和未篡改区域,实现篡改定位。实验结果表明,算法不但保证了含水印图像有较高的不可感知性,且对常见的几种处理具有较好的鲁棒性,较好的实现了图像的内容认证。     

指纹图像预处理的理论分析

本文简要介绍了指纹识别的基本步骤,分别是指纹图像预处理、指纹特征提取、指纹匹配。在图像预处理中,依次介绍了规格化处理、图像增强、二值化处理和细化处理的方法。预处理后将得到一幅宽度为一个像素的细化二值图像,然后通过特定的端点和交叉点的特征进行指纹匹配。实验表明,该方法效果良好。     

基于FPGA的图像边缘处理研究

对于图像来说,边缘是其最基本的特征.图像边缘是指灰度有明显反差变化的周围像素的集合,它是一种具有方向和幅值的矢量,是进行图像分割、图像识别以及纹理分析的重要基础,灰度的突变是其在图像中的主要表现.要正确检测出这种灰度的非连续性,确定其在图像中的准确位置,就需要采取相应的边缘检测方法.文章介绍了基于FPGA的图像边缘检测器的研究和设计过程,这种处理方式一方面显著提高了图像边缘处理的水平,另一方面还提高了图像处理的速度.另外,还根据边缘检测结果提出了具体的后续处理方法,以供参考.     

灰度图像二值化算法研究

在很多图像处理的过程中,经常需要对灰度图像进行二值化。本文对几种常用的图像二值化算法进行了阐述,并通过仿真,进行比较研究。根据实验结果,阐明了各种算法的优缺点。     

基于主动视觉的摄像机线性自标定方法

为了解决传统摄像机标定方法的精确度差和使用不方便,本文提出了一种基于主动视觉的摄像机线性自标定方法,该方法通过控制摄像机做一次纯轴向运动来确定主点坐标,再做一次纯旋转运动利用单应性矩阵与旋转矩阵的关系确定摄像机的其他三个内参数。这种基于主动视觉的自标定方法原理简单、实现方便、可操作性强。实验结果表明,该方法能够比较准确地标定出摄像机的所有内参数。摄像机标定是计算机视觉中的一项基本任务。传统的标定方法是通过结构的物体(如标定块,标定板等)在图像中的投影计算摄像机的内参数。但是这种方法必须要有标定物,在很多实际应用中难以实现。为了解决传统摄像机标定方法的精确度差和使用不方便,     

综合运输体系下快捷货运服务网络结构影响因素分析

在综合运输体系下如何建立一个合理的快捷货运服务网络是政府部门和货物运营公司共同关心的问题。文章阐述了影响快捷货运服务网络结构的主要因素,并运用系统结构模型进行了快捷货运服务网络结构影响因素分析：首先构造多个影响因素的有向连接图,建立了邻接矩阵,然后基于推移率定律运算获得可达性矩阵,并最终建立了快捷货运服务网络结构影响因素的递阶层次结构,从而为识别快捷货运服务网络结构影响因素的主次、关联关系奠定了基础。     

RANDOM WALKS ON REGULAR POLYHEDRA AND OTHER DISTANCE–REGULAR GRAPHS

In this paper we consider Markov chains of the following type: the state space is the set of vertices of a connected, regular graph, and for each vertex transitions are to the adjacent vertices, with equal probabilities. When the mean first–passage matrix F of such a Markov chain is symmetric, the expectation and variance of first–entrance times, recurrence times, number of visits to a vertex and the expectation of the number of different vertices visited, can easily be computed from the entries of F. The method is most effective, when the underlying graph is distance–regular; then F is symmetric and the entries of F can easily be obtained from the graph.     

Assessing Aggregate Structural Change

The aim of this paper is to investigate the evolution of Italian aggregate structural change over the years 1965–85. We use annual input–output (IO) tables in current and constant prices to derive an aggregate index of structural change. We adopt several techniques for such an explorative analysis. First, we borrow from qualitative matrix analysis and graph theory some basic concepts to assess direct and indirect links among sectors, and interrelatedness measures are derived in a straightforward way. However, qualitative analysis of indirect links may be flawed, since it can establish a path that is quantitatively negligible. Then, we turn our attention to a non-standard quantitative index derived from structural path analysis, expressed by a simple function of the input matrix determinant. Since empirical findings indicate a structural break in 1975, we derive another measure of technical change: the dominant eigenvalue. Such an index has several interesting properties but no clear relationship to the circularity process implicit in the Leontief model. Results for constant- and actual-price IO tables are discussed and compared with main macro-economic variables over the sample. Empirical findings indicate a relationship between investment, variability in final demand and aggregate structural change.     

Visual displays: analytical study and applications to graphs and real data

Principal axis methods such as principal component analysis (PCA) and correspondence analysis (CA) are useful for identifying structures in data through interesting planar graphic displays. However, some kinds of data sets can be dealt alternatively with PCA or CA. This paper focuses on methods, such as PCA and CA, and on visual displays. Our aim is to illustrate the implications for a potential user of selecting either method, and its advantages and disadvantages, from an applied point of view. This is a matter covered broadly in textbooks and elsewhere considering theoretical arguments. Our purpose is to contribute to the comparison between these methods, over the same data set, in order to illustrate them for the practitioner. In the first part of this paper we present a novel analytical study of a binary matrix associated with a non-oriented axis-symmetric graph and show that CA outperforms standardized PCA for the reconstitution and visualization of such kind of graphs. In the second part we present a case using real data dealing with the distribution of employees in different economic sectors for the countries of the European Union, analyzed by means of standardized PCA and two-way CA, in order to see the differences between the two methods in practice.     

Bayesian Model Selection of Gaussian Directed Acyclic Graph Structures

During the last years, graphical models have become a popular tool to represent dependencies among variables in many scientific areas. Typically, the objective is to discover dependence relationships that can be represented through a directed acyclic graph (DAG). The set of all conditional independencies encoded by a DAG determines its Markov property. In general, DAGs encoding the same conditional independencies are not distinguishable from observational data and can be collected into equivalence classes, each one represented by a chain graph called essential graph (EG). However, both the DAG and EG space grow super exponentially in the number of variables, and so, graph structural learning requires the adoption of Markov chain Monte Carlo (MCMC) techniques. In this paper, we review some recent results on Bayesian model selection of Gaussian DAG models under a unified framework. These results are based on closed-form expressions for the marginal likelihood of a DAG and EG structure, which is obtained from a few suitable assumptions on the prior for model parameters. We then introduce a general MCMC scheme that can be adopted both for model selection of DAGs and EGs together with a couple of applications on real data sets.     

Disconnecting graphs by removing vertices: a polyhedral approach

In this paper, we consider the problem of disconnecting a graph by removing as few vertices as possible, such that no component of the disconnected graph has more than a given number of vertices. We give applications of this problem, present a formulation for it, and describe some polyhedral results. Furthermore, we establish ties with other polytopes and show how these relations can be used to obtain facets of our polytope. Finally, we give some computational results.     

基于模糊图论的企业物流绩效评价耗时模型

运用模糊图论的基本理论,建立了企业物流绩效评价评价耗时模型,包括评价过程的多重有向模糊图和广义模糊矩阵。模型首先对企业物流绩效评价评价各环节之间的关系进行了直观的描述,接着对评价各环节耗费的时间进行了定量的描述。通过该模型,可以定量计算评价工作总的耗费时间,为控制评价工作的时间提供了依据。     

Bayesian Nash equilibrium and variational inequalities

This paper provides a sufficient condition for the existence and uniqueness of a Bayesian Nash equilibrium by regarding it as a solution of a variational inequality. The payoff gradient of a game is defined as a vector whose component is a partial derivative of each player’s payoff function with respect to the player’s own action. If the Jacobian matrix of the payoff gradient is negative definite for each state, then a Bayesian Nash equilibrium is unique. This result unifies and generalizes the uniqueness of an equilibrium in a complete information game by Rosen (1965) and that in a team by Radner (1962). In a Bayesian game played on a network, the Jacobian matrix of the payoff gradient coincides with the weighted adjacency matrix of the underlying graph.     

Consistent graphs with signed points

A signed graph is obtained from a graph when each line is given either a positive or a negative sign. We now define a marked graph analogously by signing the points of a graph. In both of these the sign of a cycle is the product of the signs of the lines or points, respectively. In a balanced signed graph or in a consistent marked graph, every cycle is positive. Our object is to investigate consistent marked graphs. It is shown that if such a graph has both positive and negative points, it cannot be highly connected; more precisely, it is not 3-connected. We conclude with a series of constructions which show that a given consistent marked graph can often be reduced to smaller ones.