Recognition of Partially Occluded Objects Based on Segmentation by Median Filtering of Extended Direction Code

The image contour is segmented into lines, arcs and smooth curves by median filtering of extended direction code. Based on this segmentation, a set of new local invariant features are proposed to recognize partially occluded objects, which is more reasonable compared with conventional corner features. The matching results of some typical examples shows that these features are robust ,effective in recognition.

SELF-DUAL PERMUTATION CODES OVER FORMAL POWER SERIES RINGS AND FINITE PRINCIPAL IDEAL RINGS

In this paper, we study self-dual permutation codes over formal power series rings and finite principal ideal rings. We first give some results on the torsion codes associated with the linear codes over formal power series rings. These results allow for obtaining some conditions for non-existence of self-dual permutation codes over formal power series rings. Finally, we describe self-dual permutation codes over finite principal ideal rings by examining permutation codes over their component chain rings.

Self-Dual Permutation Codes over Finite Chain Rings

Permutation codes over finite chain rings are introduced; by using the character of the finite chain rings and the knowledge of representation of group, some conditions for existence or non-existence of self-dual permutation codes over finite chain rings are obtained. Specially, when the group is a direct product of a 2-group and a T-group, and the group action is transitive, the sufficient and necessary condition of the existence of permutation codes is given.

The Self-dual Codes over Formal Power Series Rings

The codes of formal power series rings R_∞=F[[r]]={sum from i=0 to ∞(a_lr^l|a_l∈F)}and finite chain rings R_i={a_0+a_1r+…+a_(i-1)r^(i-1)|a_i∈F}have close relationship in lifts and projection.In this paper,we study self-dual codes over R_∞by means of self-dual codes over Ri,and give some characterizations of self-dual codes over R_∞.

Self-dual Codes Defined on Factor Graphs

A definition of a self-dual code on graph and a procedure based on factor graphs to judge a self-dual code were presented. Three contributions of this paper were described as follows. To begin with, transform T_ R→L were defined, which was the basis of self-dual codes defined on graphs and played a key role in the paper. The second were that a self-dual code could be defined on factor graph, which was much different from conventional algebraic method. The third was that a factor graph approach to judge a self-dual code was illustrated, which took advantage of duality properties of factor graphs and our proposed transform T_ R→L to offer a convenient and geometrically intuitive process to judge a self-dual code.

ON SELF-DUAL PERMUTATION CODES

Permutation codes over finite fields are introduced, some conditions for existence or non-existence of self-dual permutation codes are obtained.

Construction of Self-dual Codes over F_p+vF_p

In this paper, we give an explicit construction for self-dual codes over F_p+vF_p(v^2= v) and determine all the self-dual codes over F_p+ vF_p by using self-dual codes over finite field F_p, where p is a prime.

New MDS Euclidean and Hermitian Self-Dual Codes over Finite Fields

In this paper, we construct MDS Euclidean self-dual codes which are ex-tended cyclic duadic codes. And we obtain many new MDS Euclidean self-dual codes. We also construct MDS Hermitian self-dual codes from generalized Reed-Solomon codes and constacyclic codes.

Self-dual Codes with Symplectic Inner Product

In this paper, we discuss a kind of Hermitian inner product - symplectic inner product, which is different from the original inner product - Euclidean inner product. According to the definition of symplectic inner product, the codes under the symplectic inner product have better properties than those under the general Hermitian inner product. Here we present the necessary and sufficient condition for judging whether a linear code C over Fp with a generator matrix in the standard form is a symplectic self-dual code. In addition, we give a method for constructing a new symplectic self-dual codes over Fp, which is simpler than others.

基于EBRCG的API结构模式信息增强方法研究

针对API调用模式缺乏结构信息及结果高冗余等问题,提出了基于扩展的分支保留调用图(the Extended Branch-Reserving Call Graph,EBRCG)的API结构模式信息增强方法。以Java开源项目源代码为研究对象,使用EBRCG来表示Java类的方法的结构信息,在EBRCG中,同时考虑了API调用语句、分支语句(将if语句和所有循环语句视为分支语句)、switch-case多分支语句、异常语句等,并提出了EBRCG裁剪算法来获取特定API调用模式的代码结构。同时,采用聚类和排序的方法对API调用模式的多个代码结构信息进行筛选,最终选择具有代表性的API调用模式的代码结构。为验证该方法的效果,将该方法与TextRank方法进行了3组实验比较。结果显示,该方法能有效地获取API调用模式的代码结构,相比TextRank方法能更准确地描述API的使用,有一定的研究意义,并为软件开发人员提供了参考。

基于改进蚁群算法的多无人机协同任务分配

针对城市物流场景下多无人机协同任务分配问题,考虑无人机性能、飞行成本和配送点紧迫度不同,建立更加符合真实场景的组合优化模型,提出了一种融合遗传算法的改进蚁群算法。基于无人机和配送点之间的访问关系,根据遗传算法中基因编码思想采用了一种整数组合基因编码方式以生成种群个体,为提高算法搜索能力设计了一种扰动算子的改进交叉操作。将遗传算法的结果转化为蚁群算法的初始信息素,通过一种自适应信息素机制和引入扩展启发量的策略来指导种群搜索方向,从而平衡算法的全局搜索能力和局部搜索能力。仿真实验表明,所提出的改进算法能很好的跳出局部最优,并且能够高效、稳定地找出合理的无人机配送方案。

基于码重奇偶性的扩展BCH码盲识别

实际应用中的扩展BCH(Bose Chaudhuri Hocquenghem)码具有码率高、码长多变、结构复合等特点,在编码识别领域,对高码率编码码长估计、特定码型识别等方面仍缺乏研究成果。针对上述问题,提出了一种基于码重奇偶性的码长估计方法,在此基础上,利用有限域傅氏变换识别编码码型,实现了扩展BCH码的识别。该识别过程有别于其他文献中已知码型、再识别其他参数的方法,更加符合实际情况。仿真结果表明,所提方法能够实现二进制对称信道下的高码率扩展BCH码的识别。当误码率小于1.5×10^(-2)时,除了码长为128的编码,对其他码长的编码识别准确率能达到94%以上,当误码率小于7×10^(-3)时,识别准确率接近100%,识别性能优于现有算法。所提方法能有效实现对扩展BCH码的识别,具有较好的误码适应能力。

CONSTACYCLIC CODES OF ARBITRARY LENGTHS OVER RING Z_(p^m) +vZ_(p^m)

By constructing a Gray map, constacyclic codes of arbitrary lengths over ring R =Z p m +vZ pmare studied, wherev 2=v. The structure of constacyclic codes over R and their dual codes are obtained. A necessary and sufficient condition for a linear code to be self-dual constacyclic is given. In particular,(1 +(v +1)ap)-constacyclic codes over R are classified in terms of generator polynomial, where a is a unit of Z m.

Construction of Regular Rate-Compatible LDPC Convolutional Codes

In this paper, we propose a new method to derive a family of regular rate-compatible low-density parity-check（RC-LDPC） convolutional codes from RC-LDPC block codes. In the RC-LDPC convolutional family, each extended sub-matrix of each extended code is obtained by choosing specified elements from two fixed matrices HE1K and HE1K, which are derived by modifying the extended matrices HE1 and HE2 of a systematic RC-LDPC block code. The proposed method which is based on graph extension simplifies the design, and prevent the defects caused by the puncturing method. It can be used to generate both regular and irregular RC-LDPC convolutional codes. All resulted codes in the family are systematic which simplify the encoder structure and have maximum encoding memories which ensure the property. Simulation results show the family collectively offer a steady improvement in performance with code compatibility over binary-input additive white Gaussian noise channel（BI-AWGNC）.

Duadic Codes over the Ring Fq[u] /m- and Their Gray Images

Let m ≥ 2 be any natural number and let be a finite non-chain ring, where and q is a prime power congruent to 1 modulo (m-1). In this paper we study duadic codes over the ring and their extensions. A Gray map from to is defined which preserves self duality of linear codes. As a consequence self-dual, formally self-dual and self-orthogonal codes over are constructed. Some examples are also given to illustrate this.

Polyadic Cyclic Codes over a Non-Chain Ring

Let f(u) and g(v) be two polynomials of degree k and l respectively, not both linear which split into distinct linear factors over Fq. Let be a finite commutative non-chain ring. In this paper, we study polyadic codes and their extensions over the ring R. We give examples of some polyadic codes which are optimal with respect to Griesmer type bound for rings. A Gray map is defined from which preserves duality. The Gray images of polyadic codes and their extensions over the ring R lead to construction of self-dual, isodual, self-orthogonal and complementary dual (LCD) codes over Fq. Some examples are also given to illustrate this.

Performances of Chaos Coded Modulation Schemes Based on Mod-MAP Mapping and High Dimensional LDPC Based Mod-MAP Mapping with Belief Propagation

In this paper, we propose to generalize the coding schemes first proposed by Kozic &al to high spectral efficient modulation schemes. We study at first Chaos Coded Modulation based on the use of small dimensional modulo-MAP encoding process and we give a solution to study the distance spectrum of such coding schemes to accurately predict their performances. However, the obtained performances are quite poor. To improve them, we use then a high dimensional modulo-MAP mapping process similar to the low-density generator-matrix codes (LDGM) introduced by Kozic &al. The main difference with their work is that we use an encoding and decoding process on GF (2m) which enables to obtain better performances while preserving a quite simple decoding algorithm when we use the Extended Min-Sum (EMS) algorithm of Declercq &Fossorier.

A Study on Minimal Codewords in the Hamming Codes

In this paper, we show that if Wmax 〈 6 for the Hamming code Ham （r, 2）, then all of the nonzero codewords of Ham （r, 2） are minimal and if Wrnax 〈 8 for the extended Hamming code Hfim （r, 2）, then all of the nonzero codewords ofHfim （r, 2） are minimal, where Wmax is the maximum nonzero weight in Ham （r, 2） and Hfim （r, 2）.

基于二维码的移动机器人多传感器融合定位及路径跟踪研究

本文针对移动机器人运动过程中,里程计的累计误差导致机器人定位不精确的问题,提出一种基于二维码、里程计和惯性测量单元的移动机器人多传感器融合定位及路径跟踪方法,并使用阿克曼型机器人进行实验。实验证明:该方法具有可行性,能有效地消除累计误差。

On Isodual Double Toeplitz Codes

Double Toeplitz(shortly DT)codes are introduced here as a generalization of double circulant codes.The authors show that such a code is isodual,hence formally self-dual(FSD).FSD codes form a far-reaching generalization of self-dual codes,the most important class of codes of rate one-half.Self-dual DT codes are characterized as double circulant or double negacirculant.Likewise,even binary DT codes are characterized as double circulant.Numerical examples obtained by exhaustive search show that the codes constructed have best-known minimum distance,up to one unit,amongst formally self-dual codes,and sometimes improve on the known values.For q=2,the authors find four improvements on the best-known values of the minimum distance of FSD codes.Over F4 an explicit construction of DT codes,based on quadratic residues in a prime field,performs equally well.The authors show that DT codes are asymptotically good over Fq.Specifically,the authors construct DT codes arbitrarily close to the asymptotic Varshamov-Gilbert bound for codes of rate one half.