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1.
根据墨西哥帽小波的特点,提出两种新的函数,对化学信号进行n次小波变换,得到了信号的近似2n阶导数.由数值微分法和小波变换法对模拟信号计算的结果发现对于含噪信号,小波变换法有效滤除了噪声,所得结果的信噪比明显高于前一种方法;同时还可分离重叠峰,提高谱图分辨率.该方法函数形式简单,易于编程,为处理化学信号提供了新的途径.  相似文献   

2.
基于新阈值函数的二进小波变换信号去噪研究   总被引:3,自引:1,他引:2  
由于二进小波变换的小波基函数存在着一定的冗余,基于二进小波变换的去噪效果要好于离散小波变换的信号去噪·噪声阈值的准确估计和阈值函数的选择对去噪精度有着显著的影响·在分析高斯噪声的二进小波变换特性基础上,提出了一种改进的二进小波变换去噪方法·采用一种新的阈值函数,克服了Donoho软阈值方法中估计小波系数与分解小波系数存在恒定偏差的缺陷·仿真结果表明,改进的二进小波去噪方法不仅可以有效地抑制信号奇异点处的pseudo-Gibbs现象,而且消噪精度高于传统的软硬阈值方法·  相似文献   

3.
一种基于小波的白噪声消除方法   总被引:2,自引:0,他引:2  
介绍了小波变换的基本理论,研究了信号和白噪声在小波变换下的不同特性,在此基础上提出了一种新的基于小波变换的白噪声消除方法.仿真结果证明,这种方法具有很好的去噪声效果.  相似文献   

4.
作者在分析小波变换时频局部化特性的基础上,选取样条小波函数对语音信号进行处理,给出了基于小波变换极大模的基音周期检测方法和实验结果。  相似文献   

5.
介绍了一种新颖的信号处理方法-小波变换.利用三阶样条小波分析了信号的奇异点与其小波变换的关系,并通过ECG信号的小波变换,分析了小波变换的抗干扰能力.最后提出了一种以小波变换为基础的QRS波检测方法  相似文献   

6.
采用连续样条小波变换方法对化学中高噪声重叠信号中峰位置和峰数目的提取进行了分析,讨论了信噪比、重叠程度、信号相邻峰高比对重叠信号解析的影响.结果表明:对于信噪比低至1的高噪声信号,采用连续样条小波变换处理能够得到重叠信号的峰位置和峰数目;连续样条小波变换对于高噪声重叠信号具有较好的解析能力,为低含量多组分物质的复合信号的定性定量分析提供了基础;该方法与离散小波变换法相比,数据点无须为2^n(n为整数),并且不需要对信号进行多次分解,因此简单快速。  相似文献   

7.
小波变换数字算法及其在高压输电线保护中的应用   总被引:3,自引:0,他引:3  
从电力系统继电保护应用的角度,结合香农采样定理,深入探讨了连续信号和离散信号的小波变换的关系,给出了离散信号的积分小波变换和离散小波变换的数字计算方法。从理论上研究了信号小波变换的误差与尺度函数和小波函数的关系。结果表明:小波变换的误差来源一是信号在尺度空间的投影与抽样空间的投影转换,二是小波以及尺度函数的选择。小波的时频定位特性越好,即时间频率窗的面积越小,计算误差越小。阐述了小波分析在电力系统高压输电线路的行波保护以及单端暂态量保护中的应用。  相似文献   

8.
小波神经网络在模拟电路故障诊断中的应用研究   总被引:8,自引:0,他引:8  
对模拟电路提出了一种基于小波与神经网络辅助式结合的故障诊断方法.该方法用小波变换作为模拟电路故障信号的预处理器,大大减少神经网络的输入数目,简化神经网络结构和减少它的训练时间,提高辨识故障能力.在介绍该故障诊断方法的基本原理后。给出了小波函数及故障特征选择的方法.  相似文献   

9.
列出门函数、单边指数函数和阶跃函数这三种具体信号的连续小波变换与傅里叶变换的表达式,并通过表达式对连续小波变换与傅里叶变换进行比较.结果表明:傅里叶变换是线性变换,具有统一性和相似性,但不具有局部化性质,不能作局部分析;小波变换也是线性变换,同样具有统一性和相似性,并且是稳定的,还具有时一频同时局部性和自适应性.由此说明了小波变换在分析和处理信号时比傅里叶变换更加灵活、更加全面和深入.  相似文献   

10.
小波变换时频特性的信号识别   总被引:6,自引:0,他引:6  
研究了小波变换时频特性的信号识别及其在复合材料损伤检测中的应用.根据小波变换的框架重构理论及时频相空间理论,提取信号的时频域特征,通过比较原信号的时频空间和小波变换相空间的相同部分,得到能反映同样时频特征的小波级数展开项和的个数,并用误差函数的最小化提取能反映时频性质的小波系数.以此作为小波神经网络的学习参数,经过学习后,使之能对信号进行识别.应用此方法对复合材料试验过程中的复杂曲线进行了实验识别,效果很好.从小波时频特性提取的信号特征,在时间和频率方面都能体现原信号所包括的本质信息,供助B样条小波神经网络的识别结果,达到了预期目的.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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