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151.
Grade estimation using fuzzy- set algorithms 总被引:1,自引:0,他引:1
T. D. Pham 《Mathematical Geology》1997,29(2):291-305
This paper presents a new approach for estimating unknown ore grades within a mining deposit in a fuzzy environment using
fuzzy c- means clustering and a fuzzy inference system. Based on a collection of cluster centers obtained from fuzzy c- means,
a fuzzy rule base and fuzzy search domains are established to compute grades at these cluster centers. These cluter center-
grade pairs act as control information in the fuzzy space- grade system in order to infer unknown grades on the basis of fuzzy
interpolation, fuzzy extrapolation, and a defuzzification process of fuzzy control. 相似文献
152.
地震和测井资料联合反演储层物性参数的方法 总被引:2,自引:0,他引:2
为了充分利用测井资料较高的纵向分辨率及其反映井壁周围物性直接准确的特点和地震资料良好的横向可追踪性,针对厚储层和薄储层地震—地质模型分别提出了利用测井和地震资料联合反演纵横波速度和密度参数的方法。理论模型的计算结果表明,反演方法是切实可行的 相似文献
153.
杨文强 《物探化探计算技术》1997,19(3):270-273,278
为研究高密度电阻率法对各种三维地电体的反映规律,本文介绍了正演程序编制的方法并给出了计算实例。 相似文献
154.
本文从最大后验概率密度观点出发,在数据噪音向量和待求模型向量为具有零均值的独立高斯随机过程的假设前提下,建立起了随机反演的非线性系统方程;给出了模型方差估计的函数表达式,并在文章最后,证明了反演解的稀疏性,即解释了随机反演的输出解的高分辨率特征。文章在最小二乘反演方法的基础上,发展并完善了随机反演方法的理论基础;揭示了随机反演方法与最小二乘反演方法之间的本质区别;阐述了随机反演方法的优越性,并指出了其广阔的应用前景。 相似文献
155.
ChinaisoneOfthecountrieswhichsufferfromthemostserioussoilerosionintheworld,andthehillyandgullyareasof~PlateauinthemiddlereachesOftheYellowRiverarethemostseriouserosionareainChina.Inthisarea,themainerosivefactorsarerainfallandrunoff.Sometimes,thesedimentyieldinasinglefloodeventcanbe40%oftheannualsedimentload.Therefore,itisveryimPOrtanttostudytheyieldandgraphOfSedimentOfsinglefindevent.Forthispn~,thispaperiswritten.AInongsedimentmodelsforsinglefloodevent,moreandmoreattentionwaspaidtOunitse… 相似文献
156.
Zhou Cuiying Wang Hongwei Wang Mei and Zhang YuxiaSeismological Bureau of Shandong Province Jinan China Center for Analysis Prediction SSB Beijing China 《中国地震研究》1997,(4)
In order to solve the problem of early estimation of moderately strong aftershock duration time in an earthquake sequence,this study has been conducted.First,the definition of the strong aftershock has been given.It is pointed out that there is a difference in the strong aftershock duration time between the main shock type sequence and the strong earthquake swarm sequence.After dividing the three cases,i.e.,a strong aftershock duration time larger than 1 day,smaller than 1 day,and no strong aftershock occurred in a main shock type sequence by using the pattern recognition method,we gave the rough correlation relation between strong aftershock duration time and first large shock magnitude for two types of sequences.Finally,the judgment index and method of estimating strong aftershock duration times for different sequence types have been given. 相似文献
157.
A bivariate meta-Gaussian density for use in hydrology 总被引:3,自引:0,他引:3
K. S. Kelly R. Krzysztofowicz 《Stochastic Environmental Research and Risk Assessment (SERRA)》1997,11(1):17-31
Convenient bivariate densities found in the literature are often unsuitable for modeling hydrologic variates. They either
constrain the range of association between variates, or fix the form of the marginal distributions. The bivariate meta-Gaussian
density is constructed by embedding the normal quantile transform of each variate into the Gaussian law. The density can represent
a full range of association between variates and admits arbitrarily specified marginal distributions. Modeling and estimation
can be decomposed into i) independent analyses of the marginal distributions, and ii) investigation of the dependence structure.
Both statistical and judgmental estimation procedures are possible. Some comparisons to recent applications of bivariate densities
in the hydrologic literature motivate and illustrate the model. 相似文献
158.
Thierry Rolland Stéphanie Fayolle Arlette Cazaubon Stéphane Pagnetti 《Aquatic Sciences - Research Across Boundaries》1997,59(1):57-73
In a sub-alpine river, the Asse, with an unpredictable discharge regime, chlorophyll, density and taxonomic diversity of both
drifting and periphytic communities were studied from a methodical approach. The investigations based on stamping two close
cross-sections to know their spatial distributions in a heterogeneous bed substrate showed a heterogeneous pattern of colonization
mainly influenced by hydrological variables as the current velocity, the size of the substrata (gravel-pebble-boulder). For
the drifting algae, mainly composed with benthic species temporarily unhooked to the substrata, the heterogeneity of the distribution
was reduced in fast flow which induced a mixing of the whole mass of water.
For the periphyton, some results indicated that the greatest diversity and the highest chlorophyll concentration were found
on pebble substratum where the current velocity was moderate. These results have also shown that the classical methods used
to day for investigations were inadequate for most Mediterranean rivers.
It was really difficult to estimate the water quality from classical index created for use in regular large plain rivers. 相似文献
159.
Y. -K. Tung K. -C. Yeh J. -C. Yang 《Stochastic Environmental Research and Risk Assessment (SERRA)》1997,11(2):145-171
Hydrologic regionalization is a useful tool that allows for the transfer of hydrological information from gaged sites to ungaged
sites. This study developed regional regression equations that relate the two parameters in Nash's IUH model to the basin
characteristics for 42 major watersheds in Taiwan. In the process of developing the regional equations, different regression
procedures including the conventional univariate regression, multivariate regression, and seemingly unrelated regression were
used. Multivariate regression and seeming unrelated regression were applied because there exists a rather strong correlation
between the Nash's IUH parameters. Furthermore, a validation study was conducted to examine the predictability of regional
equations derived by different regression procedures. The study indicates that hydrologic regionalization involving several
dependent variables should consider their correlations in the process of establishing the regional equations. The consideration
of such correlation will enhance the predictability of resulting regional equations as compared with the ones from the conventional
univariate regression procedure. 相似文献
160.
K. -C. Yeh J. -C. Yang Y. -K. Tung 《Stochastic Environmental Research and Risk Assessment (SERRA)》1997,11(2):173-192
Hydrologic model parameters obtained from regional regression equations are subject to uncertainty. Consequently, hydrologic
model outputs based on the stochastic parameters are random. This paper presents a systematic analysis of uncertainty associated
with the two parameters, N and K, in Nash's IUH model from different regional regression equations. The uncertainty features
associated with N and K are further incorporated to assess the uncertainty of the resulting IUH. Numerical results indicate
that uncertainty of N and K from the regional regression equations are too significant to be ignored. 相似文献