基于树型小波变换的图像检索研究

本文通过分析纹理图像经过小波分解后的能量变化特点,比较和分析了利用树型小波变换和塔式小波变换进行图像检索的方法,提出了基于树型小波变换的相似性度量方法.通过排序的评价方法进行评价,研究表明,树型小波分解方法具有较好的纹理区分能力.     

社会网络顶点间相似性度量及其应用

集对分析作为处理系统确定性与不确定性相互作用的数学理论,可用来处理存在不确定关系的复杂社会网络。首先,应用集对分析理论,将社会网络作为一个同异反系统(确定不确定系统),采用集对联系度刻画顶点间的同异反关系,综合考虑顶点的局部特征和拓扑结构对顶点相似性的贡献,提出加权聚集系数联系度的顶点间相似性度量方法。该度量方法可以更好地刻画网络结构特征,克服传统局部相似性度量指标对某些顶点间相似性值的低估,降低全局相似性度量指标的计算复杂度。其次,为了将该相似性度量指标应用于社区发现,与凝聚型层次聚类算法相结合,使其适用于具有相似性度量对象的复杂网络社区发现问题。最后,在社会网络上进行社区挖掘实验,并与经典社区发现算法进行比较,实验结果表明了该相似性度量指标的正确性及有效性。     

基于局部相似性的复杂网络社区发现方法

复杂网络是复杂系统的典型表现形式, 社区结构是复杂网络最重要的结构特征之一. 针对复杂网络的社区结构发现问题, 本文提出一种新的局部相似性度量, 并结合层次聚类算法用于社区结构发现. 相对全局的相似性度量, 本文提出的相似性度量具有较低的计算开销; 同时又能很好地刻画网络的结构特征, 克服了传统局部相似性度量在某些情形下对节点相似性的低估倾向. 为了将局部相似性度量用于社区结构发现, 推广了传统的Ward层次聚类算法, 使之适用于具有相似性度量的任意对象, 并将其用于复杂网络社区结构发现. 在合成和真实世界的网络上进行了实验, 并与典型算法进行了比较, 实验结果表明所提算法的可行性和有效性.     

非对称信息在链接预测中的应用

针对基于节点相似性的链接关系预测中因未考虑非对称信息导致预测准确度降低的问题,提出一种新的增加非对称信息的节点相似性度量方法。首先,分析了基于共同邻居（CN）的相似性度量算法的缺陷在于仅考虑CN的数量而未考虑各自节点的所有邻居的数量;然后,将节点之间的相似性度量定义为共同节点与所有邻居节点的比值,融合节点间对称相似信息和非对称相似信息,对节点间的相似程度进行深入细致的刻画;最后,将该方法应用到复杂网络中进行链接关系的预测。在真实数据集上的实验结果表明,与目前多种基于共邻的相似性度量方法——CN、AA、资源分配（RA）相比,所提方法提升了节点相似性度量的准确性,并且可以提高复杂网络中链接关系预测的准确度。     

高维数据的相似性度量研究

数据间的相似性度量是进一步分析数据集整体特性的一个重要基础。针对高维数据的相似性度量问题,提出了一种基于子空间的相似性度量方法。该方法先将高维空间进行基于网格的划分,然后在划分后的子空间内计算数据间的相似性。理论分析表明,在合理选定网格划分参数的前提下,该方法可有效减小维度灾难对高维数据相似性度量的影响。     

度量空间一种自底向上索引树构造算法

在多媒体或复杂对象数据库中,相似性搜索是一种非常重要的操作,这些操作一般可以归结为度量空间的相似性查询．提出一种新的度量空间索引数据结构（bu-tree）,它是基于自底向上的分层聚类来构造索引结构,而传统的度量空间数据结构大部分是基于自顶向下构造的方法．相对于传统的构造方法,bu-tree可以在更小的索引半径内包含更多的对象,这样有利于查询的筛选．给出了bu-tree的构造算法以及相应的范围查询算法．实验表明,bu-tree的性能好于sa-tree,特别是在度量空间不是均匀分布或者查询具有较低的选择度情况下．     

基于XML Store的程序代码查询匹配算法

在研究程序代码相似性度量方法的基础上,提出一种基于XML store的程序代码查询匹配算法。由于XML store以树型结构保存XML文件,算法将通过查询XML store中DVM树来对判断程序之间是否具有相同结构的子树,进行相似度度量。最后,通过在原型系统上进行的一系列实验,进一步证明了提出的算法在程序代码相似度度量实际应用中的可行性和有效性。     

基于聚类的复杂网络社团发现算法

对基于聚类技术的复杂网络社团发现算法进行研究,分析网络中结点间的相似性度量方法,提出把复杂网络中的结点转化为向量的顶点到向量映射(MVV)算法,把网络中的结点转化成适合聚类算法的数据结构形式.对不同聚类算法及相似性度量方法的性能进行比较分析,结果表明,MVV算法可以提高发现复杂网络中社团的能力.     

基于多向测度和属性相似度的混合协同过滤

传统协同过滤算法中相似性度量方法存在度量不准确,不能如实反映信息的问题,导致推荐质量不高。针对这一问题,提出一种新的基于多向测度和项目属性的相似性计算方法。利用多向测度方法计算用户对项目的评分相似性,同时结合项目属性计算用户对项目属性的偏好相似度,通过加权因子得到用户间的最终相似性。实验结果表明该方法较传统方法显著提高了推荐精度。     

基于隐私保护的数据相似性度量

数据对象间的相似性度量是数据挖掘中一个重要的内容。针对如何在不共享精确数据的条件下,安全计算数据对象间的相似性问题,提出了几种基于安全多方计算协议的算法。算法很好的隐藏数据,保护隐私信息,且对相似性计算的结果没有影响。     

A spherical representation for recognition of free-form surfaces

Introduces a new surface representation for recognizing curved objects. The authors approach begins by representing an object by a discrete mesh of points built from range data or from a geometric model of the object. The mesh is computed from the data by deforming a standard shaped mesh, for example, an ellipsoid, until it fits the surface of the object. The authors define local regularity constraints that the mesh must satisfy. The authors then define a canonical mapping between the mesh describing the object and a standard spherical mesh. A surface curvature index that is pose-invariant is stored at every node of the mesh. The authors use this object representation for recognition by comparing the spherical model of a reference object with the model extracted from a new observed scene. The authors show how the similarity between reference model and observed data can be evaluated and they show how the pose of the reference object in the observed scene can be easily computed using this representation. The authors present results on real range images which show that this approach to modelling and recognizing 3D objects has three main advantages: (1) it is applicable to complex curved surfaces that cannot be handled by conventional techniques; (2) it reduces the recognition problem to the computation of similarity between spherical distributions; in particular, the recognition algorithm does not require any combinatorial search; and (3) even though it is based on a spherical mapping, the approach can handle occlusions and partial views     

Contour based object detection using part bundles

In this paper we propose a novel framework for contour based object detection from cluttered environments. Given a contour model for a class of objects, it is first decomposed into fragments hierarchically. Then, we group these fragments into part bundles, where a part bundle can contain overlapping fragments. Given a new image with set of edge fragments we develop an efficient voting method using local shape similarity between part bundles and edge fragments that generates high quality candidate part configurations. We then use global shape similarity between the part configurations and the model contour to find optimal configuration. Furthermore, we show that appearance information can be used for improving detection for objects with distinctive texture when model contour does not sufficiently capture deformation of the objects.     

相似度在GIS对象比较中的应用

在地理信息系统中，很多复杂的数据对象可以用多个不同类型的简单属性数据来表示，但对这些复杂数据对象的比较是个难题，而数据对象之间的相似度表示可以很好地解决这个问题。该文就复杂对象问的相似度表示和计算进行了探讨，给出了一个计算混合类型数据对象相似度的方法，并论述了该相似度计算方法在复杂对象之间的比较和排序中的应用。     

A flexible similarity measure for 3D shapes recognition

This paper is devoted to presenting a new strategy for 3D objects recognition using a flexible similarity measure based on the recent modeling wave (MW) topology in spherical models. MW topology allows us to establish an n-connectivity relationship in 3D objects modeling meshes. Using the complete object model, a study on considering different partial information of the model has been carried out to recognize an object. For this, we have introduced a new feature called cone-curvature (CC), which originates from the MW concept. CC gives an extended geometrical surroundings knowledge for every node of the mesh model and allows us to define a robust and adaptable similarity measure between objects for a specific model database. The defined similarity metric has been successfully tested in our lab using range data of a wide variety of 3D shapes. Finally, we show the applicability of our method presenting experimentation for recognition on noise and occlusion conditions in complex scenes.     

Geometry-aware domain decomposition for T-spline-based manifold modeling

This paper presents a new and effective method to construct manifold T-splines of complicated topology/geometry. The fundamental idea of our novel approach is the geometry-aware object segmentation, by which an arbitrarily complicated surface model can be decomposed into a group of disjoint components that comprise branches, handles, and base patches. Such a domain decomposition simplifies objects of arbitrary topological type into a family of genus-zero/one open surfaces, each of which can be conformally parameterized into a set of rectangles. In contrast to the conventional decomposition approaches, our method can guarantee that the cutting locus are consistent on the parametric domain. As a result, the resultant T-splines of decomposed components are automatically glued and have high-order continuity everywhere except at the extraordinary points. We show that the number of extraordinary points of the domain manifold is bounded by the number of segmented components. Furthermore, the entire mesh-to-spline data conversion pipeline can be implemented with full automation, and thus, has potential in shape modeling and reverse engineering applications of complicated real-world objects.     

The Alignment of Objects with Smooth Surfaces

This paper examines the recognition of rigid objects bounded by smooth surfaces, using an alignment approach. The projected image of such an object changes during rotation in a manner that is generally difficult to predict. An approach to this problem is suggested, using the 3D surface curvature at the points along the silhouette. The curvature information requires a single number for each point along the object′s silhouette, the radial curvature at the point. We have implemented this method and tested it on images of complex 3D objects. Models of the viewed objects were acquired using three images of each object. The implemented scheme was found to give accurate predictions of the objects′ appearances for large transformations. Using this method, a small number of (viewer-centered) models can be used to predict the new appearance of an object from any given viewpoint.     

Detecting outlier pairs in complex network based on link structure and semantic relationship

In this paper, we propose an outlier pair detection method, called LSOutPair, which discovers the vast differences between link structure and semantic relationship. LSOutPair addresses three important challenges: (1) how can we measure the target object's link similarity among multi-typed objects and multi-typed relations? (2) how can we measure the semantic similarity using the short texts? (3) how can we find the objects’ maximum differences between link structure and semantic relationship? To tackle these challenges, LSOutPair applies three main techniques: (1) two matrices are used to store link similarity and semantic similarity, (2) a k-step index algorithm, which calculates the term weighting for each object, (3) applying the linear transformation of Frobenius norm to matrices can obtain the top-K outlier pairs. LSOutPair considers link and semantics in complex network simultaneously, which is a new attempt in data mining. Substantial experiments show that LSOutPair is very effective for outlier pair detection.     

Fractals and Solid Modeling

Trying to combine fractal geometry and solid modeling seems to be a contradiction in itself, In this paper a new type of 3D objects is presented that accomplishes this combination in a specific way. Objects with a fractal macro structure and a 3D solid micro structure can be specified and rendered efficiently by using context free, attribute, geometric grammars. This new object type can be incorporated into the CSG-modeling technique (Constructive Solid Geometry) in two ways: a) using CSG for the specification of the micro structure of the new object type, b) using these fractal like objects as a new type of primitive in the CSG model. Ray tracing is used for generating high quality images of these geometrically complex objects.     

复杂约束条件下的分层装配模型

为在装配建模过程中保证信息的完整性,提出基于装配对象属性的分层约束装配模型。以需求块的概念为基础,对装配对象采用先分块再分层的方法进行分组,分析各块、各层之间复杂的约束关系,构建分层约束装配图,完成装配顺序算法的设计。实验结果表明,该模型能有效表达装配形成过程的顺序,实现装配关系的分解和时序化,对象之间的交互过程简单真实且便于操作。