PATHS BETWEEN TWO VERTICES IN A TREE GRAPH

Let T(G)be the tree graph of a simple graph G.It is proved that ifT and T′are two vertices of T(G)such that d_T(G)(T)(?)d_T(G}(T′),then there ared_T(G)(T) internally disjoint paths in T(G) joining T and T′.     

THE NORMALITY OF CAYLEY GRAPHS OF SIMPLE GROUP A_5 WITH SMALL VALENCIES

1.IntroductionLetGbeafinitegroup.ForaCayleysubsetSofGnotcontainingtheidentityelement1,theCayley(di)graphX~Cay(G,S)ofGwithrespecttoSisdefinedasthedirectedgraphwithvertexsetV(X)=GandedgesetE(X)={(g,sg)IgEG,s6S}.IfS=S--',thentheadjacencyrelationissymmet...     

EDGE RECONSTRUCTION OF PLANAR GRAPHS WITH MINIMUM DEGREE AT LEAST THREE-(IV)

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COHERENT, REGULAR AND SIMPLE SYSTEMS IN ZERO DECOMPOSITIONS OF PARTIAL DIFFERENTIAL SYSTEMS

1.IntroductionWeareconcernedwithalgebraicdifferentialpolynomials(abbreviatedas'd-pcis)inafinitenumberofdifferentialindeterminatesoveradifferentialfieldofcharacteristic0.Givenafinitesetofsuchd-pcis,wewouldliketostudyd-Zero(),thedifferentialalgebraicsetdefinedbyPoverauniversaldifferentialfield.Wemayaskwhetherd-Zero()isempty,whetherad-pcivanishesond-Zero()(differentialradicalidealmembershipproblem),whatthedimensionofd-Zero()is,howtodecomposed-Zero()intoirreduciblealgebraicdifferentialsets,andso…     

HAJóS'''' CONJECTURE AND CONNECTIVITY OF EULERIAN GRAPHS

Hajos' conjecture asserts that a simple eulerian graph on n vertices can be decomposed into at most n-1/2 circuits. In this paper, we propose a new conjecture which is equivalent to Hajos' conjecture, and show that to prove Hajos' conjecture, it is sufficient to prove this new conjecture for 3-connected graphs. Furthermore, a special 3-cut is considered also.     

THE LINEAR ARBORICITY OF COMPOSITION GRAPHS

The linear arboricity la(G) of a graph G is the minimum number of linear forests which partition the edges of G. Akiyama, Exoo and Harary conjectured that la(G) = [△(G) 1/2] for any regular graph G. In this paper, we prove the conjecture for some composition graphs, in particular, for complete multipartite graphs.     

PACKING A TREE OF ORDER p WITH A （p,p＋1）—GRAPH

Let G1 and G2 be two graphs of the same order,If G1 is isomorphic to a spanning subgraph of the complement of G2,then we say that G1 and G2 are packable.A graph G is called a (p,m)-graph if G has p vertices and m edges.The main purpose of this paper is to present a necessary and sufficient condition for a tree of order p and a (p,p 1)-graph to be packable.     

A PROOF OF BROERSMA AND VELDMAN'S CONJECTURES

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ON NICE SEQUENCES CONCERNING HAMILTONICITY OF GRAPHS

In the paper, the (k-1)-traceable-nice ((k-1)-T-nice) and k-homogeneously-traceable-nice (k-HT-nice) sequence are defined similarly to the definition of k-Hamilton-nice (k-H-nice) and (k+1)-Hamilton-connected-nice ((k+1)-HC-nice) sequence. Therelationships among these four nice sequences are discussed. The main results are asfollows: Let_η=(a_1, a_2,…, a_(k+1) be a non-negative rational sequence, k≥2. (1) If η is(k+1)-HC-nice and a_(k+1)=2, then η is k-HT-nice, (2) If η is k-HT-nice and a_(k+1)=2,then η is (k-1)-T-nice, (3) If η is k-H-nice, then η is k-HT-nice. Meanwhile, four unsolvedproblems on these topics are proposed.     

OBSERVABILITY OF EXTENDED TIMED EVENT GRAPH

In this paper, we study some results of extended timed event graph (ETEG) by using graph theory's methods in the dioid framework. A necessary and sufficient condition for the observability of ETEG is obtained and ETEG's standard structure is also established.     

北京市知识密集型服务业增加值的 Markov SCGM(1, 1)C预测模型

将1991-2009年北京市知识密集型服务业增加值作为原始数据序列, 对部分统计信息修正后, 应用单因子系统云灰色模型拟合时序数据的总体趋势; 然后将所得相对误差作为随机波动过程, 用马尔柯夫链原理对其状态进行预测; 最后综合运用MarkovSCGM(1, 1)_C模型, 对未来3年北京市知识密集型服务业增加值进行了预测, 结果表明具有良好的预测精度.     

CYCLES CONTAINING MANY VERTICES OF SUBSETS IN GRAPHS WITH LARGE DEGREE SUMS AND NEIGHBORHOOD UNIONS

1. ResultsWe use[IJ for terminology and notations not defined here and consider simple graph only.Let G be a graph of order n and X C V(G). A graph G is called 1--tough if w(G\S) 5 ISIfor any S g V(G) with w(G\S) > 1, where w(G\S) denotes the number of components ofgraph G\S. A cycle C of G is called X-longest if no cycle of G contains more venices of Xthan C, and by c(X) we denote the number of venices of X in an X-longest cycle. A cycle Cof G is called X-dominating if all neigh…     

Tunable-Q contourlet transform for image representation

A novel tunable-quality-factor (tunable-Q) contourlet transform for geometric image representation is proposed. The Laplacian pyramid in original contourlet decomposes a signal into channels that have the same bandwidth on a logarithmic scale, and is not suitable for images with different behavior in frequency domain. We employ a new tunable-Q decomposition defined in the frequency domain by which one can flexibly tune the bandwidth of decomposition channels. With an acceptable redundancy, thistunable-Q contourlet is also anti-aliasing and its basis is sharply localized in the desired area of frequency and spatial domain. Our experiments in nonlinear approximation and denoising show that the contourlet using a better-suitable quality factor can achieve a more promising performance and often outperform wavelets and the previous contourlets both in visual quality and in terms of peak signal-to-noise ratio.     

基于图拉普拉斯嵌入的合成孔径雷达时变窄带干扰抑制算法

合成孔径雷达(synthetic aperture radar, SAR)作为一种宽带系统, 常与同频段内其他有源电磁系统发生冲突, 这些信号相较于宽带SAR系统而言, 大部分是窄带干扰(narrow-band interference, NBI), 会对高分辨SAR成像系统产生严重干扰。早期关于NBI抑制问题的研究中, 很少有人注意到NBIs在不同脉冲之间可能具有局部时变特性, 这削弱了某些经典方法在干扰抑制上的性能。因此, 本文提出了一种图拉普拉斯嵌入(graph Laplacian embedding, GLE)算法, 通过在不同脉冲信号之间构建拉普拉斯嵌入关系来抑制NBIs。这使得局部时变的干扰能够被嵌入到非线性低维流形中, 并被有效去除。对实测受NBI干扰的SAR数据进行处理, 处理后的结果证明了所提方法的有效性。     

基于结构分解的北京能源强度影响因素研究

基于投入产出分析的结构分解技术,开展北京市能源强度的驱动因素研究,将其分解成:能源投入系数、完全需要系数、最终需求结构系数、最终需求、最终能源消耗系数五个因素.利用北京市1997-2012年实物价值型能源投入产出可比价序列表进行实证分析,研究表明:1)总体来说,北京市能源强度一直呈下降趋势;2)能源投入系数和最终需求的变化是能源强度下降的主要驱动因素;3)完全需要系数和最终需求结构在不同阶段对能源强度的降低起到了不同的促进或抑制作用;4)最终能源消费系数的影响作用较为微弱.     

Image decomposition using adaptive regularization and div （BMO）

In order to avoid staircasing effect and preserve small scale texture information for the classical total variation regularization, a new minimization energy functional model for image decomposition is proposed. Firstly, an adaptive regularization based on the local feature of images is introduced to substitute total variational regularization. The oscillatory component containing texture and/or noise is modeled in generalized function space div (BMO). And then, the existence and uniqueness of the minimizer for proposed model are proved. Finally, the gradient descent flow of the Euler-Lagrange equations for the new model is numerically implemented by using a finite difference method. Experiments show that the proposed model is very robust to noise, and the staircasing effect is avoided efficiently, while edges and textures are well remained.     

基于因子图的协同定位与误差估计算法

针对多自主水下航行器协同定位系统中从艇的数据融合问题,首先建立了协同定位系统的数学模型,然后分析了速度误差及航向误差对从艇定位误差的影响,同时设计了协同定位及误差估计的因子图模型.接着,提出了基于高斯噪声的协同定位及误差估计算法,利用均值和方差在因子图各节点间传递完成对从艇位置、速度误差和航向误差的估计.为了验证算法的...     

基于时频图自主学习的海面小目标检测

多维特征检测方法已成功运用于海面小目标探测中.针对人工特征提取的局限性,将检测问题转变为两分类问题,提出了一种基于时频图深度学习的目标检测方法.首先,将一维观测回波变换到二维时频域,并通过归一化时频图进行白化预处理.其次,建立半仿真含目标回波数据库,解决两类训练样本非均衡问题.然后,搭建迁移学习模型自主学习时频图特性,...     

c个修理工同步多重休假的k/n(G)表决可修系统

本文首次将"多个修理工同步多重休假"规则引入到c个修理工的k/n(G)表决可修系统中,在假设部件的工作寿命、故障后的修理时间和修理工的休假时间 分别服从参数λ(>0)、μ(>0)和θ(>0)的负指数分布下,利用拟生灭过程 和矩阵几何解方法,讨论了在稳态下系统处于各状态的概率分布,以及一些刻画系统性能的可靠性指标 和排队指标,如系统的稳态可用度、稳态故障频度和故障部件的等待修理时间等,并且讨论了四种特殊情况: 1) c=1,θ→+∞; 2) c=1,k=1,θ→+∞; 3) c=1,k=n,θ→+∞; 4) c=1,k=n-1,θ→+∞.最后给出了在c=2,n=6,k=3,λ=1/10,μ=1/5,θ=1/2的数值计算例子.     

稀疏码分多址收发端改进方案的设计

为降低传统稀疏码分多址接入(sparse code multiple access,SCMA)系统的译码复杂度,同时保证系统误比特率(bit error ratio,BER)性能,考虑信道质量因素提出SCMA系统收发端改进方案.在接收端,提出基于信道质量动态选择节点改进消息传递算法(message passing al...