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1.
基于二维小波分析的景观特征尺度识别   总被引:2,自引:0,他引:2  
采用3种常用小波基(Haar、Daubechies和Symlet),探讨了二维小波分析在沈阳地区城市、城乡交错区和农村3种景观类型特征尺度识别中的有效性.由于二维小波分析的变换尺度必须为2的整数次幂,这会导致景观中一些特征尺度无法精确识别,故本文将各景观类型影像像元大小分别重采样为3、3.5、4和4.5 m,以增加分析时的尺度密度.结果表明:应用二维小波分析可清晰地识别景观特征尺度;Haar、Daubechies、Symle可分别作为城乡交错区景观、城市景观和农村景观特征尺度识别的最优小波基;Haar和Symlet均可应用于农村景观精细特征尺度的识别和城乡交错区景观边界的检测;Daubechies和Symlet可分别用于城市景观和农村景观的边界检测.  相似文献   

2.
基于小波包熵的运动意识任务分类研究   总被引:1,自引:0,他引:1  
提出了以小波包熵作为脑电特征向量的左右手运动意识任务分类方法,对被测试者想象左右手运动时的脑电小波包熵动态变化情况及分析窗口长度的选择进行了研究.结果表明,小波包熵能很好地反映左右手运动想象的脑电特征变化,用线性判别式算法对脑电特征进行识别,分类正确率达到92.14%.由于小波包熵的计算比较简单,稳定性好,识别率高,为大脑运动意识任务的分类提供了新思路.  相似文献   

3.
本文描述了基于二进制小波变换(DyWT),ECG信号中QRS综合波的检测。设计-小波它适合于QRS检测,将基于心电信号的特殊的特征的特征为小波的尺度。DyWT较之其它方法最基本的优点为强有力的抑制噪声检测以及在分析随时间变化ECG波形时的灵活性。  相似文献   

4.
吴捷  张宁  杨卓  张涛 《生物物理学报》2007,23(6):482-487
尝试将小波相干方法应用于事件相关电位实验的脑电信号分析中。实验分为三组:听觉任务、震动任务1和震动任务2。对12个受试者的实验数据进行40Hz左右的小波相干分析,计算了前额脑区与其他各脑区之间的相干性,发现震动任务的小波相干值大于听觉任务并有显著差异,且在不同的任务中,各脑区的小波相干值有其明显不同的分布特征,且随时间呈有规律的变化。分析体现了小波相干在短时脑电信号处理上的优势。  相似文献   

5.
初级视觉的Gabor函数模型和变换尺度为3是初级视觉处理外界信息的主要特征。在此基础上,由于小波所具有的多分辨特性与视觉处理由粗到细的过程相一致,因而,希望存在一类能够表征这两个初级视觉特征的小波变换。从这点出发,本文先给出了具有变换尺度为3的正交Haar基,而后给出了具有以上两个特征的小波基和小波滤波器。我们将其应用到图象信息的压缩上,着重与传统二进的小波变换图象压缩的效果进行了比较,结果说明具有视觉特征的小波变换能够提供良好的图象压缩效果和主观视觉效果  相似文献   

6.
南京市城市景观的特征尺度   总被引:2,自引:0,他引:2  
郁文  刘茂松  徐驰  陈奋飞  安树青 《生态学报》2007,27(4):1480-1488
在RS技术支持下,采用分辨率为10m的SPOT-5遥感影像为数据源,分别应用Haar、Morlet、Mexican Hat 3种基小波,对南京市江北城郊、主城区和东南城郊3种不同景观类型进行了特征尺度研究。结果表明,Modet基小波最适于进行城市景观的特征尺度检测,Mexican Hat基小波对粒级嵌套结构检测效果稍差,而Haar基小波不适于对连续型数据源的景观进行特征尺度检测。Morlet基小波的一维小波分析结果表明,南京市江北城郊和东南城郊都存在1个对应于各自农田斑块平均粒径的特征尺度,分别为362m和446m,而主城区则检测出存在3个特征尺度,即:292、835m和2200m,分别对应于建筑小区、小型街区和大型街区的平均粒径,显示主城区存在具有等级结构特征的“建筑小区-小型街区-大型街区”的粒级嵌套结构,揭示了城区具有比城郊复杂得多的粒级结构特征。  相似文献   

7.
一个新的脑电信号分析系统:小波分析理论的运用   总被引:2,自引:2,他引:0  
小波变换是一种把时间、频率(或尺度)两域结合起来的分析方法。它被誉为“分析信号的数学显微镜”。本系统将小波变换用于脑电信号分析,是一个在Windows3.1下开发的脑电分析系统。  相似文献   

8.
景观生态学中的尺度分析方法   总被引:9,自引:0,他引:9  
蔡博峰    于嵘  《生态学报》2008,28(5):2279-2279~2287
多尺度空间分析法是发现和识别景观特征尺度的主要方法.当前这类方法很多,缺乏归类和对比分析评价.基于空间类型变量和数值变量,对多尺度空间分析方法进行了重新梳理.同时对当前常用的尺度分析方法:半方差分析、尺度方差分析、小波分析和孔隙度指数分析,以中国三北防护林为例,对比了各种尺度分析方法的特点和优劣.结果表明,在特征尺度的识别上:小波方差方法清晰明了;半方差分析法灵活简捷,结果明显;尺度方差分析法和孔隙度指数法在本研究中的判识结果不甚明显.在计算速度上:半方差分析法计算量最大、耗时最长,尺度方差次之,小波方差速度最快,孔隙度指数法计算速度快于前两种,慢于小波方差分析方法.半方差分析方法简单灵活,而且相关理论方法成熟,但缺乏对大尺度格局的整体把握,而小波分析恰恰能很好的弥补这一不足.最后提出,半方差分析和小波变换相结合将会是最优的尺度分析方法.  相似文献   

9.
初级视觉的Gabor函数模型和变换尺度为3是初级视觉处理外界信息的主要特征,在此基础上,由于小波所具有的多分辨特性与视觉处理由粗到细的过程相一致,因而,希望存在一类能够表征这两个初高觉特征的小波亦换。从这点出发,本文先给出了具有变换尺度为3的正交Haar基,而后给出了具有以上两个特征的小波基和小波滤波器。  相似文献   

10.
小波分析在生态环境研究中的应用初探   总被引:3,自引:0,他引:3  
韦桂峰  王肇鼎 《生态科学》2003,22(2):116-119
小波分析(Wavelet Analysis)是时间-频率分析领域近年来迅速发展的一种新技术,具有多时间尺度,多层次和多分辨的特性,已被广泛地应用在信号分析、信息分析和地球科学研究上.本文以大亚湾大鹏澳水域2002年春秋两季浮游植物30d连续观测资料为例,首次运用小波技术分析浮游植物对生境变化的响应特征.结果表明,通过小波变换的浮游植物数量(细胞密度)的时间序列,存在各自的优势周期和多时间尺度结构特征,而春秋两季浮游植物细胞密度的优势周期和多时间尺度结构,在大尺度上大致相同,但在小尺度结构上稍有差别;使用不同小波变换(如Mexh小波变换和Morlet小波变换)可以取得各自不同特点的结果.本文对小波分析技术在生态环境研究的初步应用说明,小波分析技术可以对生态系统中浮游植物的动态变化进行多时间尺度,多层次和多分辨的分析,为深入研究和预测浮游植物的动态变化提供一种新的分析手段.  相似文献   

11.
《L'Anthropologie》2018,122(3):437-446
In the past, the author replicated several Stone Age art objects, preferentially those made from mammoth tusk, using authentic tools and techniques. This contribution describes the results of his research work and the experiences he collected during the experiments, not only in relation to the material and its properties but also concerning the use of flint tools and their technical aspects. In addition, the author gives a brief overview about his subsequent considerations regarding early artisans, their skills and their social position.  相似文献   

12.
A new manner of representing a class of abstract cell models previously developed by the author is presented. Some of the properties of this dynamical representation are explored, and their consequences discussed.  相似文献   

13.
Biochemistry (Moscow) - In the article, the author examines the properties of Y-box-binding protein (YB-1) and expression of the YBX-1 gene in various malignant tumors and provides the data from...  相似文献   

14.
阿拉伯半乳糖蛋白(arabinogalactan-proteins,以下简称AGPs)是广泛存在于高等动植物的一种糖蛋白。本文就其化学组成、特性、合成、代谢和其在植物细胞分化中的某些作用的研究进展作了介绍。  相似文献   

15.
Epidemiologists often use ratio-type indices (rate ratio, risk ratio and odds ratio) to quantify the association between exposure and disease. By comparison, less attention has been paid to effect measures on a difference scale (excess rate or excess risk). The excess relative risk (ERR) used primarily by radiation epidemiologists is of peculiar interest here, in that it involves both difference and ratio operations. The ERR index (but not the difference-type indices) is estimable in case-control studies. Using the theory of sufficient component cause model, the author shows that when there is no mechanistic interaction (no synergism in the sufficient cause sense) between the exposure under study and the stratifying variable, the ERR index (but not the ratio-type indices) in a rare-disease case-control setting should remain constant across strata and can therefore be regarded as a common effect parameter. By exploiting this homogeneity property, the related attributable fraction indices can also be estimated with greater precision. The author demonstrates the methodology (SAS codes provided) using a case-control dataset, and shows that ERR preserves the logical properties of the ratio-type indices. In light of the many desirable properties of the ERR index, the author advocates its use as an effect measure in case-control studies of rare diseases.  相似文献   

16.
The paper deals with mathematical explication of such fundamental notions of theoretical biology as space of morphological properties, proper time, diversity of forms and phenomena, spontaneous changes. The author developed a nationally geometrical picture of the animate world. A probabilistic approach is used to describe the process of evolution, whose mechanism is given by the Bayesian syllogism. It is shown how the Bayesian approach can formally describe evolutionary changes of the whole pattern of properties. The author discusses some ideas dealing with the possibility of constructing a general field theory, embracing both such phenomena that are beyond the framework of physical science.  相似文献   

17.
The author discusses methodical principles of the vaccine standardization on the basis of experience in the standardization of the cholerogen-toxoid, a principally new vaccine preparation for the immunoprophylaxis of cholera. The author substantiated the statement according to which the following should serve as the task of primary importance in the program of investigations: elaboration of a system laboratory-immunological methods for the measurement of properties and quality of preparation, and primarily of its efficacy, strictly adequate to the biological nature of the vaccine (correct), highly-reproducable and of a high informative value. Data are presented proving the fact that without solving the problem of standardization of the vaccine it is practically impossible to lay scientific foundation under the choice of the optimal vaccination doses, under the immunization scheme, and introduction into the association with other preparations etc. At the same time it is emphasized that the absence of the system of measurement of the properties responsible for the biological activity of the vaccine also excludes a possibility of successive improvement of the technology of its production.  相似文献   

18.
‘双优’两性花山葡萄浆果发育的研究   总被引:1,自引:0,他引:1  
邵宏波  张德玉   《广西植物》1994,14(4):349-353
对两性花山葡萄‘双优’及雌性花‘左山一’山葡萄等生长发育规律及其果实性状进行了系统的研究,结果表明:浆果的生长发育曲线呈单‘S’型,表现出慢—快—慢的生长节奏。双优的果实性状明显优于其它山葡萄品种,而且能够自花结实,但双优的座果率低于‘左山一’。  相似文献   

19.
The author presents materials concerning the study of the toxic properties of 12 pertussis cultures used in the USSR for the production of vaccines. As a result of studying the toxic properties of the microbes in the test of the change of the weight of mice, and in experiments of testing the anaphylactogenic and histamine-sensitizing activities it was revealed that the strains of pertussis microbes differed by the quantitative content in them of the thermolabile toxin, endotoxin, lymphocytosis-stimulating and histamine-sensitizing factors; therefore, the period of keeping the pertussis suspensions for 1.5 months from the moment of detoxication proved to be inadequate for some of the strains. Since the toxic properties of the strains failed to correlate with their protective activity, in recommendation of pertussis strains for the production of pertussis vaccine preference should be given to the strains with lesser toxic properties.  相似文献   

20.
The author studied 17 standard and local strains of shigellae of provisional serological variants (3873-50, 2000-53, 3341-53, 3615-53, 2710-54, 1621-54). By a number of biochemical signs (alkalization of citrate agar of Christiansen and Molke's lacmus, the growth on acetate medium, utilization of soluble starch) and resistance to the genus-specific dysentery bacteriophage the cultures of serological variant 2000-53 possessed no properties of shigellae and were escherichia according to the general characteristics. The enzymatic and cultural properties of the rest of provisional serological variants corresponded to the characteristics of bacteria belonging to Shigella genus.  相似文献   

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