基于模糊软集合理论的文本分类方法

为提高文本分类精度,提出一种基于模糊软集合理论的文本分类方法。该方法把文本训练集表示成模糊软集合表格形式,通过约简、构造软集合对照表方法找出待分类文本所属类别,并针对文本特征提取过程中由于相近特征而导致分类精度下降问题给出一种基于正则化互信息特征选择算法,有效地解决了上述问题。与传统的KNN和SVM分类算法相比,模糊软集合方法在文本分类的精度和准度上都有所提高。     

基于矢量空间的模糊属性认证方案

目前属性基认证方案主要是基于Shaimr的拉格朗日插值多项式进行构造的,这些方案要求认证双方所具备的相同属性个数超过某一阈值,该阈值由拉格朗日插值多项式次数决定,在一次构造中阈值唯一且不可修改。鉴于此,在矢量空间的基础上进行了新的属性基认证方案构造,打破了阈值对认证算法的限制,通过引入线性秘密分享中的授权子集,该方案无需限定属性个数,可以灵活地对被认证者进行模糊属性集定义,所有符合授权子集属性的用户均可通过认证。对新方案稍作调整,还可完成模糊属性签名运算。     

基于区块链技术的生物特征和口令双因子跨域认证方案

为解决传统跨域认证方式不多且方案复杂的问题,提出了基于区块链技术的生物特征和口令双因子跨域认证方案。首先,使用模糊提取技术提取生物特征的随机密钥参与认证,解决了生物特征泄露导致永久不可用的问题;其次,利用不易篡改的区块链存储生物特征公开信息,解决了模糊提取技术易受主动攻击威胁的问题;最后,基于区块链的分布式存储功能与联盟链架构,实现了用户在本地和异地环境下的双因子跨域认证。安全性分析和效率分析的结果表明,在安全性方面,所提方案具有抗中间人攻击、抗重放攻击等安全属性;在效率与可用性方面,该方案效率适中,用户无需携带智能卡,系统的可扩展性强。     

WWW缓冲挖掘中基于粗糙集的用户模糊兴趣建模

如何有效充分地利用WWW缓冲中的信息,其关键是建立一个合适的用户兴趣模型和构造合适的兴趣挖掘算法。用户的兴趣是一个相对模糊的概念,简单兴趣模型通过（词条,权重）来刻画兴趣,但是它的表示粒度太小,不能贴切地描述用户的兴趣。文中在充分分析WWW缓冲模型的基础上提出了基于粗糙集的用户模糊兴趣概念。利用该方法可以对WWW缓冲中的网页文档和文档集合进行统一建模,这为利用用户历史兴趣信息和进行兴趣匹配提供了便利。     

角色模型的粗集-模糊聚类分析方法

角色分析可以满足产品个性化设计系统中对于用户模型构建的需要。提出了基于粗集的模糊聚类角色分析与模型构建方法,通过构造基于粗集的模糊相似矩阵、确定角色属性的模糊相似聚类分析方法,从用户调研数据中提取典型用户属性特征,构建角色模型。该方法完善了角色分析在产品设计中的应用方法,有助于快速生成概念产品设计模型与方案。     

基于约束的模糊概念格构造算法

一般的模糊概念格在构造过程中没有考虑用户的需求,用户对模糊概念格节点中一些属性集形成的内涵并不感兴趣。为了增强模糊概念格的针对性,降低模糊概念格构造的时空复杂性,构造满足用户需求的模糊概念格,首先将用户感兴趣的背景知识定义为约束条件,根据用户关心的属性间关系,将约束条件分为3类:单约束、与约束及或约束,并采用谓词公式表示,进而提出了基于约束的模糊概念格(Constrained Fuzzy Concept Lattice,CFCL)构造算法。该算法自底向上构造模糊概念格,利用模糊概念格父子节点内涵的单调关系,采用剪枝技术来减少构造过程中判断模糊概念是否满足约束的次数,提高了模糊概念格的构造效率。实验结果表明,该算法能够有效地减少模糊概念格的存储空间和构格时间。     

基于纠错码的指静脉加密算法

对指静脉加密算法进行整体介绍,并加入纠错机制,设计了带纠错功能的指静脉加密算法。利用二进制序列发生器随机生成一个多项式系数形式的密钥,将指静脉特征点加密,在密钥恢复阶段用拉格朗日插值来恢复多项式,并利用循环冗余校验码进行校验,该方法可以找到最精确的密钥来保证多项式的准确度。实验结果表明:利用带有纠错码的模糊金库算法很好地实现了指静脉模板的加密和解密,从而达到了保护生物信息安全的要求;通过密钥长度增长可以提高系统的安全性能。     

基于理想格的高效模糊身份加密方案

模糊身份加密方案(FIBE)是将用户的身份信息通过一个属性集合来表示,加密公钥则使用另一个属性集合表示,当且仅当这两个集合足够“相近”时,解密才能正常执行.这类密码体制能够容忍部分错误公钥信息,特别适用于某些用户身份信息不能被完全正确提取的场合.文中基于理想格上的困难问题,在标准模型下,提出了一种IND-sID-CPA安全的多比特FIBE方案,并将其安全性紧致地归约为判定性R-LWE困难假设,相比以前基于标准格上的FIBE方案,新方案具有公钥长度短、密文扩展率低的优势.     

由2次单参复解析多项式构造非线性迭代函数系

为了构造新形式的分形,提出利用单参复解析2次多项式映射构造非线性迭代函数系.首先构造出2次多项式复映射在参数平面上的1周期参数集合;然后在该集合上随机挑选2个以上的参数,由这些参数建立一组迭代映射,用这组迭代映射构造出一个由单参的2次复解析压缩映射构造的非线性压缩IFS迭代函数系;最后对迭代函数系中的一个迭代映射在平面上的压缩不动点连续迭代,构造出相应的奇怪吸引子或分形.实验结果表明,该方法可以用于大量构造平面上的奇怪吸引子或分形,图形结构新颖.     

基于模糊提取的远程双向生物认证

传统的远程生物认证采用安全信道或者生物认证过程本地化的方法,具有较多的局限性.模糊提取可从生物特征输入中以容错的方式可靠地提取出均匀分布的随机密钥,当输入发生变化且变化很小时,该密钥保持不变.基于这一重要工具,给出了一个零存储的非安全信道双向生物认证方案.该方案无需存储和传输用户的生物特征,有效保护了用户隐私,并能够抵抗假冒攻击和多服务器合谋攻击.此外,所给方案还具有良好的可扩展性,集成口令和智能卡可产生多因素认证方案,并支持用户注册更新.     

A Puzzling Set of Stucco Coffers from Portici: Archaeology and Mathematics Working Together

Archaeology and mathematics work together to reconstruct the form and dimensions of a vault originally adorned with a set of twenty-five stucco coffers in the shape of concave octagons, today conserved in the Archaeological Museum in Naples. Measurements were taken to determine the curvature and orientation of the coffers. Two methods used to establish the size of the vault permitted an approximation of the vault width, making it possible to propose limited possibilities for the number of coffers transversally to the vault, and how they were displayed on it. Further studies were made of the decorative scheme in order to suggest a plausible construction process for the coffers with tools and techniques usual at the time, using only arcs of circles. For this, the front side of the coffers was considered to be plane, which led us to establish that they were included in an all-over scheme of squares and that the concentric octagonal frames were very likely drawn from two families of circles. Then differential calculus showed us that the differences due to the plane approximation of the cylindrical shape of the vault were negligible with regard to the precision of the guidelines drawn in situ. Finally we suggest a complete decorative scheme, using various clues such as subject, orientation, curvature and colours of the tesserae decorating the framing.     

基于Fuzzy Vault方案的指纹细节特征加密

指出了现有指纹Fuzzy Vault方法用于加密长度较短的密钥时安全性不足的问题,并基于Fuzzy Vault方案,提出了一种指纹细节特征加密方法.首先指定Fuzzy Vault编码多项式的幂次,并根据指定幂次对加密密钥进行处理和隐藏.通过这种处理,避开了现有方法中密钥长度决定Fuzzy Vault编码多项式幂次的弊端,解除了现有方法加密长度较短的密钥时所存在的安全隐患.     

Fingerprint-Based Fuzzy Vault: Implementation and Performance

Reliable information security mechanisms are required to combat the rising magnitude of identity theft in our society. While cryptography is a powerful tool to achieve information security, one of the main challenges in cryptosystems is to maintain the secrecy of the cryptographic keys. Though biometric authentication can be used to ensure that only the legitimate user has access to the secret keys, a biometric system itself is vulnerable to a number of threats. A critical issue in biometric systems is to protect the template of a user which is typically stored in a database or a smart card. The fuzzy vault construct is a biometric cryptosystem that secures both the secret key and the biometric template by binding them within a cryptographic framework. We present a fully automatic implementation of the fuzzy vault scheme based on fingerprint minutiae. Since the fuzzy vault stores only a transformed version of the template, aligning the query fingerprint with the template is a challenging task. We extract high curvature points derived from the fingerprint orientation field and use them as helper data to align the template and query minutiae. The helper data itself do not leak any information about the minutiae template, yet contain sufficient information to align the template and query fingerprints accurately. Further, we apply a minutiae matcher during decoding to account for nonlinear distortion and this leads to significant improvement in the genuine accept rate. We demonstrate the performance of the vault implementation on two different fingerprint databases. We also show that performance improvement can be achieved by using multiple fingerprint impressions during enrollment and verification.     

基于指纹的可撤销Fuzzy vault方案

Fuzzy vault是一种用生物特征保护密钥的加密框架,其主要缺点在于攻击者可以通过交叉比较同一用户的不同vault来获得生物模板的准确信息,从而可以破解vault。提出了一种使用基于指纹细节点的可撤销的变换模板作为生成vault的模板,保护不同密钥时采用不同变换模板,从而解决了这个问题。采用以巴特沃斯低通滤波器为核的函数组作为生成可撤销模板的变换函数。此外还使用了用户口令加密vault,从而进一步增强了被保护密钥的安全性。     

A hybrid scheme for securing fingerprint templates

In a fingerprint recognition system, templates are stored in the server database. To avoid the privacy concerns in case the database is compromised, many approaches of securing biometrics templates such as biometric encryption, salting, and noninvertible transformation are proposed to enhance privacy and security. However, a single approach may not meet all application requirements including security, diversity, and revocability. In this paper, we present a hybrid scheme for securing fingerprint templates, which integrates our novel algorithms of biometric encryption and noninvertible transformation. During biometric encryption, we perform the implementation of fingerprint fuzzy vault using a linear equation and chaff points. During noninvertible transformation, we perform a regional transformation for every minutia-centered circular region. The hybrid scheme can provide high security, diversity, and revocability. Experimental results show the comparative performance of those approaches. We also present strength analysis and threats on our scheme.     

基于B样条曲线的指纹Fuzzy Vault对齐方法

指纹设备采集到的指纹图像由于不能用统一的参照表示指纹细节点的坐标,因此,同一枚指纹分别在录入和注册时得到的指纹细节点需要对齐。本文采用指纹纹线作为指纹Fuzzy vault对齐的方法,在目标纹线上提取B样条控制点,用这些控制点数据与纹线的距离作为辅助数据来对齐指纹模板。研究分析表明这种方法不会泄露指纹细节点的任何信息。实验结果证明,这种方法具有很好的实时性并能提高指纹Fuzzy vault的配准率。     

Affine invariant image watermarking scheme based on ASIFT and Delaunay tessellation

Watermarking algorithms that resist geometric combination attacks is currently a trend of research in this field. This paper proposed a geometrically invariant watermarking scheme based on the feature points of resistance to affine transformation. The scheme used Affine Scale Invariant Feature Transform (ASIFT) to detect the feature points of the carrier image and filtrated the established feature points group depending on anti-affine properties. The obtained feature points set obtained better robustness against multiple attacks. As for robustness, we utilized the feature points set to construct the Delaunay tessellation and embedded the watermark information in the histogram of each triangle. Because of the stability of Delaunay tessellation and the basic characteristics of affine transformation, the geometric robustness of the proposed scheme achieved a good effect as was verified in experiments.

     

Perspective on Curved Surfaces in the Age of Pozzo: The <Emphasis Type="Italic">Nuova Pratica di Prospettiva</Emphasis> of Paolo Amato

The study focuses an almost unknown treatise on perspective, The Nuova Pratica di Prospettiva, written by the priest Paolo Amato (1634–1714) in the last years of his life and published posthumously in 1733. The main points of interest of the Nuova Pratica is the perspective projection on cylindrical surfaces, which exceeds the coeval ‘practical’ treatises on perspective. A detailed resume of Amato’s treatise is accompanied by geometric schemes illustrating the perspective method proposed by the author. None of the paintings made by Amato has come down to us, but the vault covering a hall added to a Norman church in Palermo shows a trompe l’oeil that was painted by one of his favorite disciples. A repeatable method, integrating laser scanning and photogrammetric surveying with digital representation tools, supported the restitution of the painted architectural scene and highlighted potential links to the content of the treatise. The geometric analysis of the orthogonal projection of the vault highlighted a rigorous and unexpected geometric scheme underlying the trompe l’oeil.     

A practical implementation of fuzzy fingerprint vault for smart cards

Biometric-based authentication can provide strong security guarantee about the identity of users. However, security of biometric data is particularly important as the compromise of the data will be permanent. To protect the biometric data, we need to store it in a non-invertible transformed version. Thus, even if the transformed version is compromised, the actual biometric data remain safe. Fuzzy vault is a cryptographic construct to secure critical data with the fingerprint data. In this paper, we implement the fuzzy fingerprint vault, combining fingerprint verification and fuzzy vault scheme to protect fingerprint templates, for the smart card environment. To implement the fuzzy fingerprint vault as a complete system, we have to consider several practical issues such as automatic fingerprint alignment, verification accuracy, template size for storing in the smart card, execution time, error correcting code, etc. Especially, we handled the fingerprints having a few minutiae by applying an adaptive degree of the polynomial, and thus our implementation result can be used for real, large-scale applications.     

Multiple Contour Finding and Perceptual Grouping using Minimal Paths

We address the problem of finding a set of contour curves in an image. We consider the problem of perceptual grouping and contour completion, where the data is a set of points in the image. A new method to find complete curves from a set of contours or edge points is presented. Our approach is based on a previous work on finding contours as minimal paths between two end points using the fast marching algorithm (L. D Cohen and R. Kimmel, International Journal of Computer Vision, Vol. 24, No. 1, pp. 57–78, 1997). Given a set of key points, we find the pairs of points that have to be linked and the paths that join them. We use the saddle points of the minimal action map. The paths are obtained by backpropagation from the saddle points to both points of each pair.In a second part, we propose a scheme that does not need key points for initialization. A set of key points is automatically selected from a larger set of admissible points. At the same time, saddle points between pairs of key points are extracted. Next, paths are drawn on the image and give the minimal paths between selected pairs of points. The set of minimal paths completes the initial set of contours and allows to close them. We illustrate the capability of our approach to close contours with examples on various images of sets of edge points of shapes with missing contours.