An Algorithm for Boundary Extraction Based on Turning Row Permutation into Sequence Permutation

Image output by computer is done row by row,the shortcoming of which is that we cannot know the topological relations between points at the image boundary.To obtain the closed boundary of the target from an image and turn points＇ row permutation of boundary into sequence permutation,an algorithm based on 4-connection relation of pixel points is proposed and the analysis of its correctness and complexity is given.Compared with classical operators and existing method,the single pixel boundary extracted from gray images by this algorithm is more complete and more distinct.Moreover,it has a lower time complexity and can eliminate the noise inside and outside the target area.The obtained sequence permutation of points is also conducive to follow-up image processing.

Quick Trickle Permutation Based on Quick Trickle Characteristic Sequence

The concept of quick trickle characteristic sequence is presented, the properties and count of quick trickle characteristic sequence are researched, the mapping relationship between quick trickle characteristic sequence and quick trickle permutation is discussed. Finally, an efficient construction of quick trickle permutation based on quick trickle characteristic sequence is given, by which quick trickle permutation can be figured out after constructing quick trickle characteristic sequence. Quick trickle permutation has good cryptographic properties.

Permutation and Complementary Algorithm to Generate Random Sequences for Binary Logic

Randomness number generation plays a key role in network, information security and IT applications. In this paper, a permutation and complementary algorithm is proposed to use vector complementary and permuta-tion operations to extend n-variable Logic function space from 22n functions to 22n * 2n! configurations for variant logic framework. Each configuration contains 2n functions can be shown in a 22n-1*22n-1 matrix. A set of visual results can be represented by their symmetric properties in W, F and C codes respec-tively to provide the essential support on the variant logic framework.

Limited Re-Sequencing for Mixed-Models with Multiple Objectives, Part II: A Permutation Approach

This research presents an approach to solving the limited re-sequencing problem for a JIT system when two objectives are considered for multiple processes. One objective is to minimize the number of setups;the other is to minimize the material usage rate [1]. For this research effort, each unique permutation of the problem’s demand structure is noted, and used as a mechanism for finding subsequent sequences. Two variants of this permutation approach are used: one employs a Monte-Carlo simulation, while the other employs a modification of Ant-Colony Optimization to find sequences satisfying the objectives of interest. Problem sets from the literature are used for assessment, and experimentation shows that the methodology presented here outperforms methodology from an earlier research effort [3].

The Linear Span of a Class of Optimal Frequency Hopping Sequences

For the anti-jamming purpose,frequency hopping sequences are required to have a large linear span. In this paper,we firstly give the linear span of a class of optimal frequency hopping sequences. The results show that the linear span is very small compared with their periods. To improve the linear span,we transform these optimal frequency hopping sequences into new optimal frequency hopping sequences with large linear span by using a general type of permutation polynomials over a finite field. Furthermore,we give the exact values of the linear span of the transformed optimal frequency hopping sequences.

Characterization and Construction of Permutation Graphs

If is a permutation of , the graph has vertices where xy is an edge of if and only if (x, y) or (y, x) is an inversion of . Any graph isomorphic to is called a permutation graph. In 1967 Gallai characterized permutation graphs in terms of forbidden induced subgraphs. In 1971 Pnueli, Lempel, and Even showed that a graph is a permutation graph if and only if both the graph and its complement have transitive orientations. In 2010 Limouzy characterized permutation graphs in terms of forbidden Seidel minors. In this paper, we characterize permutation graphs in terms of a cohesive order of its vertices. We show that only the caterpillars are permutation graphs among the trees. A simple method of constructing permutation graphs is also presented here.

一种针对驻留转换雷达的信号分选算法

复杂电磁环境下驻留转换雷达的信号分选是制约电子侦察技术发展的瓶颈,由于其复杂多变的成形规律,信号子周期难以被检测;脉冲重复周期调制类型不明,脉冲序列无法成功提取;提取的多个子周期脉冲序列无法合并为一部雷达信号,造成虚警。针对以上问题,提出一种针对驻留转换雷达的信号分选算法,利用双门限提高子周期检测概率,通过霍夫变换结合迭代自组织聚类判断信号是否属于驻留转换雷达,改进搜索算法以提取脉冲序列,依据排列熵指标将多脉冲序列合并为一部驻留转换雷达信号。仿真实验结果表明,所提算法在25%脉冲丢失率的复杂电磁环境下,可以将三部驻留转换雷达信号成功分选。

基于排序变换的混沌图像置乱算法

为了更好地利用混沌进行图像保密,基于排序变换设计了一个混沌图像置乱算法,新算法不经过量化,而是直接通过混沌序列的排序变换来得到图像置换的地址码,这就有效地避免了量化必须已知混沌轨道分布密度函数的要求,同时也降低了算法的时间复杂度。由于排序变换的强不规则性,因此使新的混沌图像置乱算法具有较强的安全保密性能。通过对新算法的置乱性能进行的实验分析结果表明,新算法不仅具有良好的置乱性能,而且可以有效地保障加密图像的安全。

基于排列熵算法的混沌伪随机序列复杂性分析

运用排列熵算法分析了离散混沌系统产生的混沌序列和混沌伪随机序列的复杂性,讨论了混沌系统参数对序列复杂性的影响情况。研究表明:多次粗粒化后得到的混沌伪随机序列保持了原有混沌序列的复杂性特点;与Logistic系统和Henon系统相比,TD-ERCS系统产生的混沌伪随机序列的复杂性大且相对稳定,是一个极具密码学应用价值的安全混沌系统。

基于超混沌的快速图像加密算法

针对现有基于超混沌的图像加密算法存在安全性不足和运行效率低的缺点,提出了一种改进算法。该算法通过优化像素置乱、像素替换和密文扩散过程进一步混淆明文图像和密文图像的关系,并通过引入新的超混沌序列量化方法,减少超混沌系统的迭代次数,提高运行效率。实验仿真结果表明,算法具有很高的安全性和实用性,可广泛运用于图像保密通信等领域。

基于伪随机序列的宏块置乱视频加密方案

研究了基于宏块置乱的视频数据加密技术。该技术首先采用m序列来产生一个超长周期的伪随机序列,然后用该序列顺序生成完全不重复的宏块置乱矩阵,最后对每个视频帧依次用不同的置乱矩阵置乱。实验结果表明,该方案加密速度快效果好,并且安全性高,不会增加码流,不改变码流格式和结构特征。

一种求解同顺序 Flowshop 排序问题的新的启发式算法

在生产调度中经常遇到工件排序问题，这类问题大多属于ＮＰ类问题．对此，目前无论在理论上还是在实际应用中，都尚未找到令人满意的一般求解方法．针对ＮＰ类问题中的一类——同顺序Ｆｌｏｗｓｈｏｐ排序问题，进行了广泛而深入的调查和比较研究，在此基础上，提出了一种新的启发式算法（简称为ＷＳＨ法），并通过大量的数据实验将该算法与目前已知较好的几种算法进行了比较．结果表明，ＷＳＨ法结构简单，计算效率高，是求解中、小规模问题的较好算法．

全距特征排列及全距置换

全距置换具有良好的密码学性质。该文首次提出了全距特征排列的概念,对全距特征排列的性质、计数进行了研究,并在此基础上讨论了全距置换与全距特征排列之间的映射关系、最后基于全距特征排列给出了全距置换的一种有效的构造方法,首先构造全距特征排列,再求出全距置换。

两类最优跳频序列集的线性复杂度

利用有限域中的一类不同于幂置换的置换多项式,将两类具有低线性复杂度的跳频序列集变换为具有高线性复杂度的最优跳频序列集。通过理论证明给出了变换以后序列线性复杂度的精确值。所得到的两类新的跳频序列集不仅具有最优的Hamming相关值,而且相对于变换前的序列集具有大的线性复杂度,可以抵抗Berlekamp-Massey算法的攻击。

基于混沌的魔方置乱算法设计

文章提出了一种新的基于混沌的魔方置乱算法,并将其应用于图像加密。该算法借用了魔方变换的思想,通过混沌映射产生两列相互独立的魔方置乱参数序列,利用这些产生的序列在空域上对图像进行置乱。实验结果分析表明,该算法具有良好的保密效果,并能在一定程度上抵抗裁剪攻击和高斯噪声干扰。

基于比特置换与核酸序列库的混沌图像加密算法

提出了一种基于比特置换与DNA序列运算的混沌图像加密的算法。该算法首先利用Chen系统产生混沌映射索引对图像进行像素位置置乱,结合蝶形网络对比特位置乱,以实现位级别置乱。再对图像进行DNA编码,并与核酸序列进行代数运算,实现像素的替代,进一步提高了加密的安全性。最后通过密文反馈来进一步增强算法的混淆和扩散特性。实验和安全性分析结果表明,该算法不仅密钥空间大、对密钥的敏感性强,而且能有效抵御统计性分析和穷举分析等攻击操作。

基于位运算和混沌序列的数字图像隐藏技术

提出了一种改进的数字图像隐藏方法。首先应用混沌系统产生混沌序列,用此混沌序列对原始图像做预处理加密,即做改进的魔方置乱和像素置换;然后对结果图像做进一步基于位运算的隐藏;最后应用评价指标对隐藏效果和安全性进行分析。实验结果表明,该方法具有较高的安全性以及加密效率。

基于三维混沌系统的图像加密算法

为了改进图像加密算法的安全性和效率,提出了一种基于三维混沌系统和位运算的数字图像加密算法,利用三维混沌序列的坐标分量分别产生置换序列和二值序列,在对待加密图像进行预处理的基础上,先应用混沌置换序列对预处理的结果图像进行基于灰度值位序列的置换操作,然后再应用产生的二值序列对结果图像的灰度值位序列进行位异或加密运算。实验结果表明,该算法具有良好的安全性和加密效果。

一种低差错平底线性复杂度的QC-LDPC码构造方法

本文给出了一种低差错平底QC-LDPC码构造方法。首先,提出了扩展近似下三角阵eALT(extern ApproximateLower Triangular)的全局矩阵构造法,通过对改进后的全局矩阵M进行矩阵置换,生成LDPC码的校验矩阵H以达到减少小停止集(Stopping Set)数量,降低差错平台(Error floor)的目的;接着,研究了校验矩阵H中短环(Short Cycle)长度与置换矩阵循环移位系数的关系,通过设置短环满足的条件搜索循环移位系数;为了降低搜索移位系数的复杂度,本文提出了一种基于等差数列的移位系数设计方法,采用数学公式计算循环移位系数,无需计算机搜索即可完全消除长度为4的短环。仿真结果表明,本文所提出的构造方法在保证线性编码复杂度的前提下,增大了码字间最小距离,提高了码字性能,同时循环移位系数设计采用结构化的方法,无需计算机搜索即可完全消除4环。

基于改进的排列法的目标威胁评估与排序模型

结合现代防空作战的特点和指挥自动化系统的工作过程,分析了影响目标威胁评估的几个重要因素,应用多属性决策中的一种改进排列法建立了数学模型,验证了其可行性。该方法不必将各属性值精确量化,只需知道各属性间的大小关系及权重就可以进行威胁评估与排序。