共查询到20条相似文献,搜索用时 31 毫秒
1.
韩道范 《吉林大学学报(地球科学版)》1988,(3)
本文介绍识别多类异常的句法模式识别方法。它将异常值分段(或分小区间)并提取特征,根据特征值确定基元,然后将异常表示成链。用已知异常的链设计最近邻分类器,通过它对未知异常进行分类和识别。文章中仅对异常识别给出了特征值的提取,链的形成以及求不同长度链之间距离的算法。 相似文献
2.
Characterization and evaluation of the factors affecting the geochemistry of groundwater in Neyveli,Tamil Nadu,India 总被引:1,自引:0,他引:1
M. Jayaprakash L. Giridharan T. Venugopal S. P. Krishna Kumar P. Periakali 《Environmental Geology》2008,54(4):855-867
In order to achieve a better understanding of the nature of the factors influencing ground water composition as well as to
specify them quantitatively, multivariate statistical analysis (factor analysis) were performed on the hydrochemical data
of this area. R-mode factor analysis was carried out on the geochemical results of the 79-groundwater samples and the factor
scores were transferred to areal maps. Fundamental chemical parameters of the groundwater have been compounded together for
characterizing and interpreting a few empirical hydrogeochemical factors controlling the chemical nature of water. R-mode
factor analysis reveals that the groundwater chemistry of the study area reflects the influence of anthropogenic activities,
silicate weathering reactions, precipitation, dissolution and subsequent percolation into the groundwater. The data have been
put into few major factors and the seasonal variation in the chemistry of water has been clearly brought out by these factors.
Factor scores were transferred to contour diagrams and the factor score analysis has been used successfully to delineate the
stations under study with various factors and the seasonal effect on the sample stations. 相似文献
3.
乘幂法在地震属性分析中的应用 总被引:9,自引:1,他引:8
作者在本文中引入了计算矩阵最大本征值及其对应的本征向量的一种数学计算方法 ,即乘幂法。属性分析中有几项常用技术如第三代相干算法和多属性信息加权处理的综合参数法 ,算法中应用了协方差矩阵本征结构的分析。将算法过程稍加分析整理 ,可发现它们仅仅需要计算最大本征值及对应的本征向量。为了提高计算效率 ,应用乘幂法代替传统使用的雅可比法等方法 ,大大缩短了计算时间 ,而且不影响计算结果的精确性。 相似文献
4.
The stability analyses of the stream function at the upper atmosphere have been conducted using a global barotropic spectral
model with a view to examine the seasonal characteristics. The growing eigen modes are classified into three groups with periods
in the range of 3–8, 11–18 and 20–50 days. This study indicates that the growth and movement of all the three types of modes
are adequately sustained by the asymmetric basic flow. All the modes grow faster in summer than in winter. The meridional
shear of the basic flow is the most important source of growth of the perturbations. In the absence of the meridional wind
shear, the eigen modes grow slowly, in which case, the quasi-nonlinear triad interaction between the waves is identified to
contribute significantly to the growth of the modes. The robustness of the eigen modes is also examined in this study using
the barotropic model at different horizontal resolutions in the triangular truncation scheme. 相似文献
5.
6.
Mihriban Şahin Mehmet Emin Korkmaz Osman Agar Abdullah Dirican 《Environmental Earth Sciences》2017,76(3):121
A screening of natural radioactivity content has been carried out in thermal water samples collected from surrounding of Central Anatolia, Turkey. The concentration levels of gross alpha and beta of 19 different samples has been determined using the low background gas-flow proportional counter. The measured gross alpha and beta activities in waters range from 0.11 to 16 Bq/L and 0.10 to 16.9 Bq/L, respectively. The measured values of gross alpha and beta concentrations are compared to previous studies in the literature and recommend WHO guideline activity concentration. The data resulting from the measurement have been statistically analyzed. 相似文献
7.
8.
The dynamic problem in micropolar viscoelastic medium has been investigated by employing eigen value approach after applying
Laplace and Fourier transformations. An example of infinite space with concentrated force at the origin has been presented
to illustrate the application of the approach. The integral transforms have been inverted by using a numerical technique to
obtain the displacement components, force stresses, couple stress and microrotation in the physical domain. The results for
these quantities are given and illustrated graphically. 相似文献
9.
Keith E. BURKE 《Geostandards and Geoanalytical Research》1985,9(1):69-78
Five samples from Suriname have been analysed for their chemical composition by 18 laboratories. The proposed reference samples are four soil samples and one lateritic bauxite. The samples were analyzed for major and minor elements as well as for 36 trace elements. More data are needed for better characterization of these samples, particularly for trace elements. 相似文献
10.
11.
P. Gustafsson 《Hydrogeology Journal》1994,2(2):9-18
In areas with little primary porosity and low bedrock hydraulic conductivity, hydrogeological properties are mainly determined by secondary factors, such as fracture zones and associated weathering. Fracture zones in areas with limited regolith cover are often detectable on satellite images as linear features originating mainly from pronounced vegatation anomalies, topographic effects or both. SPOT multispectral and panchromatic data of a 2000 km2 semi-arid area in southeastern Botswana have, in this study, been merged and interpreted in an image processing system resulting in a detailed lineament map and a delineation of dry season vegetation. The lineament data have been analyzed in a geographical information system and correlation studies of borehole and geophysical data with satellite lineaments have been carried out. The study shows that a digital approach, using satellite data in combination with existing field data, can provide a time- and cost-effective tool for the identification and narrowing of target areas for groundwater exploration in semi-arid areas. 相似文献
12.
P. D. Kovalev G. V. Shevchenko D. P. Kovalev A. G. Chernov D. Ye. Zolotukhin 《Russian Journal of Pacific Geology》2009,3(5):443-449
The November 16, 2006, Simushir and August 2, 2007, Nevelsk tsunami records obtained by bottom pressure gauges in Kholmsk
Bay are analyzed. The dominant role of the zero mode of eigen oscillations in the bay during the the wave field formation
is shown: in the initial record interval (for the remote tsunami source) and 1.5 h after the first wave (for the nearly tsunami).
Numerical modeling showed that the longer waves propagated toward Kholmsk in the case of the Nevelsk earthquake and they did
not generate eigen oscillations of the bay. These oscillations were generated 1.5 h later when the shorter waves reflected
from the Primorye coast arrived. 相似文献
13.
14.
15.
Nine CRPG and ANRT reference samples have been analyzed for Hg by flameless atomic absorption spectrophotometry. Preliminary data are given but mercury homogeneity has not been tested. Results of determinations on USGS samples are reported and compared with available literature values. 相似文献
16.
从电磁正演模拟结果出发,引入了地震勘探中“照明度”的概念,提出了电磁勘探的照明度定义及特征函数等。对照明度的地表平面特征、随深度变化特征和随频率与大地电阻率的变化特征进行了模拟分析,总结了其规律。通过分析,对广域电磁法的观测系统提出了优化建议,对野外测量的偏移角度和范围提供了借鉴。 相似文献
17.
Factor analysis has been applied to geochemical data obtained from Abra, a sediment-hosted Cu-Pb-Ba mineralization in the Late Proterozoic (1,100 Ma) Bange-mall Basin in Western Australia. From some 5,000 m of drill core 57 samples have been analyzed for 26 elements by ICP/AAS. Statistical analysis was performed on 19 elements (W, Zn, P, Pb, Co, Ni, Ba, Fe, Mn, Mg, V, Al, Ca, Cu, Ti, Sr, Na, K, Si). The data have been treated first by statistical standard methods, not considered here, then by representative graphic display of the spatial distributions of elements in a section through the mineralization, and finally by factor analysis. Three groups of elements can be distinguished according to their mode of spatial distribution in section, i.e., strata-bound, discordant, and equivocal. Eight factors have been found to explain 90% of the total variability, and the spatial distribution of these factors is discussed with respect to their geological plausibility.These findings were confirmed by previous geological and mineralogical studies. In addition, a second mineralizing fault system at the southern margin of the Abra Sub-Basin could be identified by means of the spatial distribution of factor scores. 相似文献
18.
介绍了神经网络中的自适应主分量提取(APEX)算法的实现步骤,并首次将它用在地震数据处理中.通过对地震记录进行正交分解和特征提取,可消除噪声.模型计算和实际资料处理结果表明了该方法的有效性. 相似文献
19.
20.
Measurements of 18 closely spaced beach profiles spanning Warilla Beach, N.S.W., over a 5‐year period have been examined for alongshore exchanges in beachface configuration. Horizontal slices of beach corresponding with berm, upper swash, upper and lower intertidal zones were examined by empirical orthogonal function (EOF) analysis. The first four EOF's for each of the four slices contain over 90% of the total variance for each slice. In each instance the first eigen‐function mode represents the onshore‐offshore component of beach response, and accounts for 50 to 60% of the variance. Subsequent modes describe alongshore exchange of sediment associated with large, standing, cellular water circulations of the embayment. Sediment shunts along each horizontal slice are determined by identification of nodal points in the eigen‐functions. These represent pivotal points through which sediment is transferred. The patterns of exchange vary considerably from slice to slice, reflecting change in the dominant beach processes from swash processes in the top of the beach to wave, tidal and current processes on the lower beach slope. Despite their disparity, similar periodicities are determined for the sediment exchanges in each slice. The amplitude spectra of the time series associated with each eigen‐function indicate that the exchanges take place at 24, 12 and 6 monthly periods. 相似文献