oalib

OALib Journal期刊

ISSN: 2333-9721

费用:99美元

投稿

时间不限

2016 ( 198 )

2015 ( 6765 )

2014 ( 7018 )

2013 ( 7146 )

自定义范围…

匹配条件: “赵智” ,找到相关结果约99017条。
列表显示的所有文章,均可免费获取
第1页/共99017条
每页显示
基于粒子群优化和原子特性的匹配追踪算法
Matching Pursuit Based on PSO and Atomic Property
 [PDF]

钱建, ,
Computer Science and Application (CSA) , 2014, DOI: 10.12677/CSA.2014.411039
Abstract:
由于信号稀疏表示的优良特性,已被用于信号处理很多领域,但计算量大阻碍了它在实际中的应用。粒子群优化算法简单,易于实现,且搜索效果好。论文采用匹配追踪(Matching Pursuit, MP)算法实现信号稀疏分解,利用粒子群优化算法搜索MP过程中的最优原子。根据原子特性,优化改进后的算法。仿真结果证明了新算法的可行性。
As sparse representation of signals has excellent characteristics, it has been applied in several fields of signal processing. But it has a large scale of computing, which hinders its application in practical signal processing. Particle swarm optimization is simple to be realized, and the searching result is good. In this paper, Matching Pursuit is used to realize sparse representation of signals, and particle swarm optimization is used to effectively search the best atom in the process of MP. According to the property of atoms, the improved algorithm is optimized. At last, the simulation results demonstrate the feasibility of the new algorithm.
一种基于KSVD-ETF的测量矩阵优化方法
The Optimization Design of Measurement Matrix Based on KSVD-ETF
 [PDF]

, 汪立新, 钱建
Journal of Image and Signal Processing (JISP) , 2014, DOI: 10.12677/JISP.2014.31003
Abstract:
压缩感知将数据的采样和压缩同时处理,仅需少量测量就能重建信号。测量矩阵直接影响着信号适应的稀疏度范围和重建效果。为了减小测量矩阵与稀疏变换矩阵的互相干性,提出一种基于KSVD-ETF的测量矩阵和稀疏表达字典联合优化的方法,在对测量矩阵进行ETF优化的同时利用KSVD方法更新优化表达字典,实验结果中利用该方法优化矩阵所得重建信号PSNR有所提高,表明优化测量矩阵的方法在重建效果方面有一定的优势。
Compressive sensing, a novel signal acquisition method, is a joint sensing-compression process which requires a small number of measurements to reconstruct signal. Measurement matrix, a very important part in compressive sensing, directly affects the adaptive sparsity, the required number of measurements and the reconstruct performance of the signal. In order to decrease the mutual coherence between the measurement matrix and sparse transformed matrix and improve the quality of reconstruction, this paper addresses the joint optimization between measurement matrix and sparse dictionary based on the KSVD-ETF. While optimizing the measurement matrix by ETF, we use the KSVD method to update the dictionary. The PSNR of the reconstructed signal is improved with the optimized measurement matrix from the experimental results, indicating that this method of optimizing the measurement matrix has certain advantages in the effect of reconstruction.
一种基于压缩采样的SDR接收机AIC前端设计
A Design of AIC for SDR Front-End Based on Compressive Sampling
 [PDF]

张洪峰, 钱建,
Hans Journal of Wireless Communications (HJWC) , 2014, DOI: 10.12677/HJWC.2014.46019
Abstract:
传统的射频六端口网络可以直接将射频信号下变频为基带信号,它的输出功率中包含输入信号的相位和幅度信息。在A/D采样后,我们可以得到的基带信号,但这将面临高采样率的问题。压缩采样可以以远低于奈奎斯特采样速率对信号进行有用信息的采集。该文将压缩采样技术用于六端口直接变频接收机中,提出用一种新颖的模拟信息转换器件(AIC)。这个AIC可以以较低的采样速率获取大量的数据。该AIC可能成为软件无线电接收的一个满意前端。文章对AIC前端做了性能仿真。
Conventional six-port network can down convert the RF signal to baseband directly; its output power contains the phase and amplitude information. We can get baseband signal after the A/D sampling, but it will face the problem of high sampling rate. Compressive sampling can get the useful dates at a lower sampling frequency than Nyquist rate. The paper uses compression sam-pling technique into Six-port direct conversion receiver and proposes a new analog to information conversion (AIC). The AIC can obtain large amounts of data at a lower sampling rate. The AIC may be a satisfactory front-end of software defined radio. This article does a performance simulation of AIC front-end.
跳频压缩采样的快速重构研究
Research on Fast Reconstruction of Frequency Hopping Using Compressive Sampling
 [PDF]

, 张洪峰, 钱建
Hans Journal of Wireless Communications (HJWC) , 2015, DOI: 10.12677/HJWC.2015.51003
Abstract:
受奈奎斯特采样定理的限制,对跳频信号进行传统采集需要很高的采样率,带来高昂的处理代价,压缩采样理论突破了奈奎斯特采样定理的限制,可大幅度降低信息采样率。本文以每个跳频频点最近的连续三个原子基作为该跳频频点的稀疏表示块进行迭代,削弱了相邻跳信号频率突变引起的瞬间频率展宽和数据符号调制带来的频偏影响,使之更适合实际跳频信号场合。仿真结果验证了修正的稀疏度自适应匹配追踪算法的有效性,提高了重构算法的性能。并且本文将修正的算法在不同M值下的重构概率与原算法进行了对比。
Limited by the Nyquist sampling theorem, for traditional frequency hopping signals acquisition which needs very high sampling rate and high processing cost, compression sampling theory breaks through the limitation of the Nyquist sampling theorem, and the sampling rate can be significantly reduced. The paper proposes an iteration that takes three continuous atomic bases, which have got the nearest hopping point, as the sparse representation block of this hopping point. This algorithm weakens instantaneous frequency bandwidth caused by the adjacent signal frequency mutation and the modulated data symbol brings frequency deviation effect, and makes it more suitable for the actual frequency hopping signal. The simulation results verify the correction of the effectiveness of the sparse degree of adaptive matching pursuit algorithm, which improves the performance of reconstruction algorithm. Moreover, the paper compares the correction algorithm’s reconstruction probability with the original algorithm under different M value.
小秦岭大湖金钼矿同位素地球化学特征
海香,
地质学报 , 2015,
Abstract:
砂生槐沙生适应性初步研究

植物生态学报 , 1998,
Abstract: 本文通过对西藏雅鲁藏布江中游下段沿江沙地主要建群植物砂生槐在沙地上繁殖特征、沙埋对其新枝生长的影响及在沙地植被演替中的地位的分析指出:砂生槐是通过种子的迁移侵入、定居于沙地,通过根蘖在沙地上繁殖,最后退化于种间竞争。一定程度的沙埋有利于砂生槐新枝生长。砂生槐在本区的最适生境是受风沙活动影响较大的覆沙阶地、半固定沙地和初期固定沙地。
油裂解生气是海相气源灶高效成气的重要途径

科学通报 , 2006,
Abstract: 干酪根晚期生气潜力和原油裂解气的问题关系到海相高.过成熟地区天然气的来源和勘探前景.用高磁场固体^13C核磁共振技术研究不同类型和演化程度干酪根的结构和油气潜力碳含量,Ⅰ-Ⅲ型干酪根在高.过成熟阶段气潜力碳含量均较低,表明生气潜力较小,生气数量有限;而低成熟Ⅰ型干酪根油潜力碳含量较高,表明在生油窗阶段大量生油,为后期发生油裂解生气奠定了物质基础.原油生气动力学实验表明,在160℃左右(Ro=1.6%)原油才开始大量裂解形成天然气,主生气期晚于干酪根的,但生气数量是干酪根的2—4倍,这种成因天然气富含甲基环己烷,具有不同于干酪根晚期热降解气的特征.
砂生槐沙生适应性初步研究

植物生态学报 植物生态学报 , 1998,
Abstract:
河北坝上沙漠化地区土壤特性研究——以丰宁试验区为例

中国沙漠 , 1994,
Abstract: 本文分析了丰宁试验区土壤类型、分布特点、成土条件、土壤养分、可溶性盐分、机械组成、矿物元素含量、微量元素、水分状况,并对各类土壤的生产力进行了评价。结果表明:栗钙土是本区生产力最高的土类,风砂土是栗钙土退化的产物,也是栗钙土重新发育的不同阶段,这种退化主要是土壤中细颗粒物质及养分的损失,而土壤矿物元素、微量元素并无明显变化。本区风砂土相对其它典型沙地生产力较高,与地带性土壤栗钙土相比无钙积层,适宜多种深根性植物特别是乔灌木的生长,所以本区目前沙漠化土地治理相对容易。
奈曼沙区樟子松生长状况与水分关系

中国沙漠 , 1992,
Abstract: 分析奈曼沙区樟子松的水分关系及生长状况,并与油松、小叶杨比较,结果表明樟子松较油松、小叶杨耐旱。但在无地下水或灌溉补给的迎风坡上部,樟子松片林立地水分状况严重恶化,15龄高生长速生期趋于结束,生长趋于衰退,而在地下水埋深2.4米左右的丘间低地高生长正值旺盛生长之际,这说明在年降水量仅366mm的奈曼沙区,营造樟子松必须选择适宜的立地条件,才能保证人工林的正常生长和稳定性。
第1页/共99017条
每页显示


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.