基于混合l_2/l_1范数极小化方法的块稀疏信号重构条件

研究压缩感知中的块稀疏信号重构问题,主要对混合l_2/l_1极小化方法建立了一类改进的可重构条件.具体地说,本文证明若测量矩阵满足条件δ_k+θ_(k,k)1,则混合l_2/l_1极小化方法可精确重构(无噪声情形)或鲁棒重构(有噪声情形)原始块k-稀疏信号.进而表明本文给出的新条件弱于现有文献所给出的条件.     

基于非凸优化模型的块稀疏信号恢复条件

压缩感知(compressed sensing,CS)是一种全新的信息采集与处理理论,它表明稀疏信号能够在远低于Shannon-Nyquist采样率的条件下被精确重构.现从压缩感知理论出发,对块稀疏信号重构算法进行研究,通过混合l₂/l_q(0相似文献   

线性l1模极小化问题的熵函数延拓法

本文通过利用极大熵函数构造同伦映射，建立了求解无约束线性l1模问题的熵函数延拓算法，证明了方法的收敛性，并给出了数值算例．     

基于l2/lq(q=2/3)最小化模型的块稀疏信号恢复

该文主要研究了块稀疏信号的恢复问题.利用q块限制等距性质(0相似文献   

分布式L_(1/2)正则化

研究数据集被分割并存储于不同处理器时的特征提取和变量选择问题,其中处理器通过某种网络结构相互连接.提出分布式L_(1/2)正则化方法,基于ADMM算法给出分布式L_(1/2)正则化算法,证明了算法的收敛性.算法通过相邻处理器之间完成信息交互,其变量选择结果与数据集不分割时利用L_(1/2)正则化相同.实验表明,所提出的新算法有效、实用,适合于分布式存储数据处理.     

1/2-Transitive Graphs of Order 3p

A graph X is called vertex-transitive, edge-transitive, or arc-transitive, if the automorphism group of X acts transitively on the set of vertices, edges, or arcs of X, respectively. X is said to be 1/2-transitive, if it is vertex-transitive, edge-transitive, but not arc-transitive.In this paper we determine all 1/2-transitive graphs with 3p vertices, where p is an odd prime. (See Theorem 3.4.)     

基于冗余紧框架的?2/?1极小化块稀疏压缩感知

压缩感知是(近似)稀疏信号处理的研究热点之一,它突破了Nyquist/Shannon采样率,实现了信号的高效采集和鲁棒重构.本文采用l2/l1极小化方法和BlockD-RIP理论研究了在冗余紧框架下的块稀疏信号,所获结果表明,当BlockD-RIP常数δ2k/τ满足0<δ2k/τ<0.2时,l2/l1极小化方法能够鲁棒重构原始信号,同时改进了已有的重构条件和误差上界.基于离散傅里叶变换(DFT)字典,执行了一系列仿真实验充分证实了理论结果.     

GI^（1）＋GI^（2）／G／1排队模型

对于GI^(1) GI^(2)/G/I排队模型,本借助献[1]中引入的Markov骨架过程方法求出了此模型到达过程,等待时间及队长的概率分布。     

GI/G/1 Interdeparture time and queue-length distributions via the Laguerre transform

Queue length and interdeparture distributions for GI/G/1 are obtained using the Laguerre function expansion of the waiting time distribution. The expansion of the steady state waiting time distribution is obtained here by solving a small set of linear equations in the Laguerre function expansion coefficients. Examples show the accuracy of the results and illustrate purely numerical techniques for obtaining the necessary expansions of the arrival and service distributions.     

GI(1)+GI(2)+…+GI(N)/M/1排队模型

文献[1]引入了一类具有广泛应用前景的随机过程--Markov骨架过程.本文借助这类随机过程的方法研究了GI(1)+GI(2)+…+GI(N)/M/1排队模型,求出了此模型到达过程、等待时间及队长的概率分布.     

A sharp nonasymptotic bound and phase diagram of L 1/2 regularization

We derive a sharp nonasymptotic bound of parameter estimation of the L1/2 regularization.The bound shows that the solutions of the L1/2 regularization can achieve a loss within logarithmic factor of an ideal mean squared error and therefore underlies the feasibility and effectiveness of the L1/2regularization.Interestingly,when applied to compressive sensing,the L1/2 regularization scheme has exhibited a very promising capability of completed recovery from a much less sampling information.As compared with the Lp(0 p 1) penalty,it is appeared that the L1/2 penalty can always yield the most sparse solution among all the Lp penalty when 1/2 ≤ p 1,and when 0 p 1/2,the Lp penalty exhibits the similar properties as the L1/2 penalty.This suggests that the L1/2 regularization scheme can be accepted as the best and therefore the representative of all the Lp(0 p 1) regularization schemes.     

The Dehn Function of PSL2(Z[1/p])

We show that PSL₂(Z[1/p]) admits a combing with bounded asynchronous width, and use this combing to show that PSL₂(Z[1/p]) has an exponential Dehn function. As a corollary, PSL₂(Z[1/p]) has solvable word problem and is not an automatic group.     

Optimal Ternary Linear Rate 1/2 Codes

In this paper, we classify all optimal linear[n, n/2] codes up to length 12. We show that thereis a unique optimal [10, 5, 5] code up to equivalence.     

基于样本广义方差的改进|S|~(1/2)控制图

以常用的广义方差为基础,利用矩估计的方法,从一组样本推广到多组独立样本,得出具有无偏控制限的改进|S|~(1/2)控制图,并对比说明了矩估计方法的简洁性和准确性.与标准|S|~(1/2)控制图相比,其具有更小的平均运行链长(ARL).结合实例,采用数值模拟的方法说明该控制图对过程中方差的漂移有较强的检测能力.     

1/f temporal fluctuation: detecting scale–invariance properties of seismic activity in North China

Advanced statistical methodologies have been applied to determine the temporal scaling–invariance laws in seismic activity observed in North China during the period 1980–1998. A counting statistics method is used to highlight the self-similar property of earthquake distribution in time domain, and the temporal 1/f^β fluctuation of the earthquake sequences is detected. The seismicity in North China is characterized by a time clustering effect and shows a β value that is a typical fingerprint of self-similar property. The investigations were carried out over different magnitude thresholds. To compare the behavior of seismicity fluctuations, the rescaled range analysis is also applied to explore the temporal fractal property of the same seismic sequence, and long-term persistence are detected. Both exponent β and H can be used as the key parameters describing the features of the dynamic earthquake evolution system.     

Periodic solutions of (2n+1)th order ordinary differential equations

The goal of this paper is to prove the existence and uniqueness of periodic solutions for a class of the odd order differential equations. Here the Leray-Schauder degree theory and the Schwarz inequality are used.     

A numerical exploration of compressed sampling recovery

This paper explores numerically the efficiency of ?¹ minimization for the recovery of sparse signals from compressed sampling measurements in the noiseless case. This numerical exploration is driven by a new greedy pursuit algorithm that computes sparse vectors that are difficult to recover by ?¹ minimization. The supports of these pathological vectors are also used to select sub-matrices that are ill-conditioned. This allows us to challenge theoretical identifiability criteria based on polytopes analysis and on restricted isometry conditions. We evaluate numerically the theoretical analysis without resorting to Monte-Carlo sampling, which tends to avoid worst case scenarios.