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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 3 (1971), S. 227-238 
    ISSN: 1573-8868
    Schlagwort(e): classification ; data processing ; graphics ; mapping ; mathematics ; plotting ; sampling ; statistics ; sedimentology ; stratigraphy ; grain-size analysis ; textural analysis ; glacial geology ; Pleistocene stratigraphy ; till
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Relative percentages of sand, silt, and clay from samples of the same till unit are not identical because of different lithologies in the source areas, sorting in transport, random variation, and experimental error. Random variation and experimental error can be isolated from the other two as follows. For each particle-size class of each till unit, a standard population is determined by using a normally distributed, representative group of data. New measurements are compared with the standard population and, if they compare satisfactorily, the experimental error is not significant and random variation is within the expected range for the population. The outcome of the comparison depends on numerical criteria derived from a graphical method rather than on a more commonly used one-way analysis of variance with two treatments. If the number of samples and the standard deviation of the standard population are substituted in at-test equation, a family of hyperbolas is generated, each of which corresponds to a specific number of subsamples taken from each new sample. The axes of the graphs of the hyperbolas are the standard deviation of new measurements (horizontal axis) and the difference between the means of the new measurements and the standard population (vertical axis). The area between the two branches of each hyperbola corresponds to a satisfactory comparison between the new measurements and the standard population. Measurements from a new sample can be tested by plotting their standard deviation vs. difference in means on axes containing a hyperbola corresponding to the specific number of subsamples used. If the point lies between the branches of the hyperbola, the measurements are considered reliable. But if the point lies outside this region, the measurements are repeated. Because the critical segment of the hyperbola is approximately a straight line parallel to the horizontal axis, the test is simplified to a comparison between the means of the standard population and the means of the subsample. The minimum number of subsamples required to prove significant variation between samples caused by different lithologies in the source areas and sorting in transport can be determined directly from the graphical method. The minimum number of subsamples required is the maximum number to be run for economy of effort.
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 3 (1971), S. 335-355 
    ISSN: 1573-8868
    Schlagwort(e): nearest neighbor analysis ; regression analysis ; statistics ; trend analysis ; structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract A quantitative analysis was made of the spatial arrangement of 149explosion craters in the western rift of Uganda. A variety of methods demonstrate that the spatial pattern of the craters reveals significant structural patterns that have guided volcanism to the surface. It is shown that the east-west elements in the field affected location, and the main rift fault is resolved into two main components. Tentatively, a possible dextral transform fault is identified that affected the relative location of the two main zones of activity. Grouping techniques demonstrate that crater groups obey an exponential rank-size rule and allow a mapping of the craters into energy classes that reveals a concentric pattern of energy in the field. The effect of the topography on energy levels and crater size show that only topography greater than 11,000ft could have prevented all eruptive activity, but the smaller energies and craters are sensitive to height differences on the order of the height of the rift wall, about 1000ft. Total energy in each crater class size is roughly constant, and the field energy could create one or two single craters comparable in size to small central volcanoes.
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 4 (1972), S. 1-24 
    ISSN: 1573-8868
    Schlagwort(e): discrete frequency distributions ; statistics ; general geology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Geologists unfamiliar with the application of probability theory to discrete data in other fields of research are usually acquainted with only three discrete theoretical frequency distributions: Poisson, binomial, and negative binomial distributions. In some situations these distributions may fail to adequately describe a set of experimental data. Other distributions such as the Poisson with zeros, Neyman type A, logarithmic with zeros, Poisson-binomial, and Thomas double Poisson together with the more common Poisson, binomial, and negative binomial form a generalized subset of discrete theoretical distributions, one of which should fit almost any experimental data set. A computer program is presented which allows testing of any combination of these distributions against observed discrete data.
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 4 (1972), S. 147-153 
    ISSN: 1573-8868
    Schlagwort(e): classification ; statistical inference ; statistics ; geochemistry ; petrochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract This paper embodies petrographical and statistical investigations of three gabbro occurrences. The Mangaon and Kunkeri gabbros are similar in petrography and petrochemistry, whereas they are completely different from the Vajrat gabbro. Application of recently developed statistical tests help in classifying these gabbros by using three oxides, CaO, FeO, and K2O.This study shows that the evolution of the Mangaon and Kunkeri gabbros probably proceeded along different lines as compared to the Vajrat gabbro.
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 4 (1972), S. 203-218 
    ISSN: 1573-8868
    Schlagwort(e): correlated independent variables ; regression analysis ; ridge trace ; statistics ; trend analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Multiple linear regression analysis may be used to describe the relation of one geologic variable to a number of other (independent) variables, and also may be used to fit a trend surface to geographically distributed variables. The leastsquares estimates of the regression coefficients differ unpredictably from the true coefficients if the independent variables are correlated. The estimates can be too large in absolute value, and may have the wrong sign. Also, the least-squares solution may be unstable in that replicate samples can give widely differing values of the regression coefficients. Ridgeregression analysis is a technique for removing the effect of correlations from the regression analysis. The procedure involves addition of a small constant K to the diagonal elements of the standardized covariance matrix. The estimates obtained are biased but have smaller sums of squared deviations between the coefficients and their estimates. The ridge trace, a plot of the coefficients versus K, helps determine the value of K that stabilizes the estimates. Correlations between geologic variables are common, and regression coefficients based on these data may be suspect. In trendsurface analysis, correlations between the geographic coordinates may differ widely, and extreme correlations may be introduced if higher order terms are used in the trend. Ridgeregression analysis serves to guide the geologist to a more reliable interpretation of the results of multiple regression if the independent variables are correlated.
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 4 (1972), S. 177-202 
    ISSN: 1573-8868
    Schlagwort(e): cluster analysis ; factor analysis ; mapping ; statistics ; petrology ; structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Based on the methods of Fisher and Watson,Fortran iv computer programs are presented for the following analyses of directional observations on the sphere: (1) to determine if points are randomly distributed; (2) to estimate the azimuth and inclination of the center (mean direction) of a cluster and to estimate the precision (closeness) with which points are clustered; (3) to determine if two or more clusters have the same mean direction; (4) to determine if two clusters have the same precision of clustering; and (5) to locate the pole of a greatcircle girdle of points. Limitations of these analyses for undirected directional observations on the hemisphere also are given.
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 8 (1976), S. 627-634 
    ISSN: 1573-8868
    Schlagwort(e): numerical analysis ; statistics ; mining
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract The application of the theory of random functions to problems of ore evaluation may involve computations of the covariance between the mean value of a given block and the functional value at a given point. However, an analytical solution for such a covariance does not exist for nonspherical blocks and for commonly applied models of covariance functions. Further, because this covariance is a function of the spatial arrangements of the block and the point, it has to be evaluated numerically each time for given point—block arrangements. This paper presents a readily available general solution to this problem in the form of a series of graduated curves which, together with some geometric manipulations, may be used to compute the covariance between a “point”and a two-dimensional block for all possible point—block arrangements. The availability of the graph thus eliminates the necessity of using the time-absorbing programs on computers for such computations. Finally, many of the approximations that are made in order to avoid cumbersome covariance evaluations are no longer necessary due to the ease of such computations with the help of the graph provided.
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 7 (1975), S. 129-147 
    ISSN: 1573-8868
    Schlagwort(e): correlation ; factor analysis ; regression analysis ; statistics ; allometric growth ; paleontology ; relative growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Relative growth of the Ordovician crinoid Hybocrinus punctatus (Miller and Gurley)was studied using regression, correlation, and R-mode factor analysis. Systematic growth gradients of both initial intercepts and slopes existed throughout the calyx. Development of a single plate was best correlated with growth of the directly adjacent plates and was less well correlated with that of more distant plates. A total of 86 percent of the R-mode correlation matrix variance is associated with overall size increase of all dimensions and size-correlated shape changes. Most of the remaining variance is linked with divergent growth of small groups of specimens with respect to various shape parameters.
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 9 (1977), S. 455-481 
    ISSN: 1573-8868
    Schlagwort(e): statistics ; earthquake prediction ; fracture mechanics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract The mechanism of crack growth in rocks has been the subject of much recent interest, not only on account of its engineering importance, but also as a background to the study of precursory phenomena for earthquakes. One feature which appears to play a significant role in the fracture mechanism is the formation of microfractures prior to a major failure. Microfractures also play a key role in statistical theories as developed by Weibull and later writers. Some recent work in these two fields is reviewed and the suggestion is put forward that it may be possible to extend the statistical models so as to describe the dynamics of crack formation. As a preliminary step in this direction, it is shown that a branching model for the coalescence of microfractures lead to a simple derivation of the frequency-magnitude law of fracture energies. Other methods of introducing statistical ideas into the dynamics of crack propagation are also briefly reviewed, and compared to deterministic models of crack growth.
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 10 (1978), S. 73-90 
    ISSN: 1573-8868
    Schlagwort(e): paleoecology ; sampling ; statistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract The logical structure of species richness determinations is outlined in order to explain how their accuracy is affected by nonrandomly distributed populations. The transformation of a species-area curve to a species-range curve is discussed in general terms and conditions required for accurate species richness determinations are given. Applications of the approach to scleractinid coral and pine-tree communities illustrate the method.
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 10 (1978), S. 169-193 
    ISSN: 1573-8868
    Schlagwort(e): autocorrelation ; sampling ; statistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract This paper documents the results of investigations on the variance and covariance properties of mean values within the theory of stationary random functions under a variety of conditions. Analytical expressions have been developed in each case, to facilitate direct and ready applications of the results, using the exponential function as a working model for the covariance function. These properties, in turn, have been utilized in developing mathematical expressions for estimation accuracy (error variance) of the mean estimates for one-dimensional sampling plans. Two distinctly different sampling plans have been discussed: “punctual” sampling with no significant linear extensions of the samples and “linear” sampling with significant linear extensions of samples in the direction of the section being sampled.
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 10 (1978), S. 141-167 
    ISSN: 1573-8868
    Schlagwort(e): geomorphology ; statistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract This paper is based on the study of shore line length of 12 Swedish lakes on various maps ranging in scale from 1:10,000 1:1,000,000. The lakes differ in size, from Lake Munksjön, which has an area of 1.1 km2, to Lake Vänern with an area of 5893 km2, and also in shore line irregularity, ranging from the rather regular basins of Lake Munksjön and Lake Erken to the very irregular basin of Lake Mälaren. A “new ” method, the checkered transparent paper method (the CTP-method), was adopted to measure the shore length of certain lakes on various maps. Length determination by this method can be executed quickly and easily, and in a statistically definable way, giving comparable data from various types of map. A formula defining the functional relationship between scale, shore irregularity, shore length, and lake area has been derived: $$NF = F(K_{2} - K_{1})/[K_{2} - log(s + a)]$$ or $$1_{n} = 1(K_{2} - K_{1} )/[K_{2} - log(s + a)]$$ where NF = the normalized shore development (shore irregularity) at a scale of 1:1; F = the shore development as determined on a given map scale; s = the scale factor (10,000, 50,000 etc); a = 105 ⋅ log A, where 105 = the area constant; A = the lake area in km2; K1 = log(s + a) for s = 1, i.e. the reference scale; K2 = log(s + a) for s = 6,000,000, where 6,000,000 is called the scale constant; 1 = the shore length as determined by the CTP-method on a given map; and 1n = the normalized shore length at a scale of 1:1. The formula offers a high degree of accuracy and the length of any closed geomorphic line can be determined independently of map scale, under given practical limitations. The length value obtain is the normalized length, that is the best approximation of the real, natural length at a scale of 1:1.
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 3 (1971), S. 15-41 
    ISSN: 1573-8868
    Schlagwort(e): modal analysis ; sampling ; statistics ; mineralogy ; petrology ; sedimentology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract The binomial model, commonly used to estimate counting error in point-count analysis, misestimates this error when the observation points on a grid are positively or negatively correlated. A model, called the “cell model,” is proposed as an alternative to the binomial model for use in studies, especially with coarse-grained rocks, in which such correlation is known or thought to exist. In the new model the thin section is conceptually partitioned into a number of cells (six is recommended), and the assumption is made that the proportions in the individual cells are statistically independent and that their variance does not differ from cell to cell. Empirical relations obtained from a suite of 200 thin sections of limestones are in reasonable support of the prediction that large particle size adversely affects counting error estimates based on the binomial model.
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 8 (1976), S. 9-23 
    ISSN: 1573-8868
    Schlagwort(e): cluster analysis ; statistics ; numerical taxonomy ; structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract This paper presents a technique for (1) clustering orientation data with minimum constraint on resulting partitions, and (2) testing clusters against a probability distribution defined on the unit sphere which admits elliptical symmetry about its mean. The use of an objective function to highlight certain features of the data is discussed. The technique for delineation and analysis of clusters is applied to an example problem through use of a computer code.
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 3 (1971), S. 95-121 
    ISSN: 1573-8868
    Schlagwort(e): data processing ; mapping plotting ; statistics ; general geology ; geochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Afortran iv computer program for grey-level mapping of spatial data using a CDC 6600 is described. The program produces maps for irregularly distributed data in as many as 10 intensity levels which are displayed in grey tones by a lineprinter. Unlimited map size and unrestricted data input provide for as many as 5000 data points per 13-in.-wide strip of map. The program is easily modified for other installations. Examples are given of geochemical analyses of stream sediments in Northern Ireland.
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 3 (1971), S. 357-368 
    ISSN: 1573-8868
    Schlagwort(e): multivariate analysis ; normality ; statistics ; paleontology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Data on some living (salamanders and grasshoppers) and fossil (Devonian brachiopods) animals are analyzed by means of recently developed methods for the large-scale treatment of multivariate normality. Multivariate nonnormality was found to exist in all situations, even if the univariate deviations in the skewness and kurtosis statistics proved to be without significance for the most part. The effect of logarithmically transforming the data appears to be a mixed blessing. Apart from the fact that the investigator is removed one step from the biological relationships in his data by carrying out a transformation of them, the betterment in the multivariate interconnections with respect to normality tends to be slight, despite the general improvement in the univariate values. The relationship between sample size and the multivariate normality measures b1,p and b2,p are studied empirically.
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 4 (1972), S. 25-34 
    ISSN: 1573-8868
    Schlagwort(e): correlation ; lognormal distribution ; regression analysis ; statistics ; trend analysis ; mining ; ore valuation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract The Kolar Gold Fields are some of the best known gold deposits in India. An example of ore valuation utilizing 49 ore blocks of the Oriental lode of the West Reefs, explored and developed in the Nundydroog mines, is given. In this reef system, there are large ore reserves of sulfidebearing quartz reefs, and the gold distribution is erratic both along strike and downdip. Ore valuation at present is based on the arithmetic mean of samples taken at peripheral positions of the blocks. Samples taken from internal portions of the blocks give a totally different picture of the value. To correct this discrepancy, normal regression and lognormal regression of internal block and total block values, over peripheral block values have been used to evaluate the deposits. The valuation efficiency criterion shows the logarithmic variance for distribution of ratios of unregressed and regressed block values with the corresponding arithmetic mean of internal stope values as observed inside the blocks. The studies have shown that the logarithmic variance is minimum if the logarithmic regression is used, thereby indicating maximum efficiency. Further, the undervaluation and overvaluation of low- and high-grade blocks is less for the logarithmic example. With help of the logarithmic regression equation an effective pay limit of 177.8 in.-dwt has been found for selective mining, for peripheral block values corresponding to the official pay limit of 240 in.-dwt.
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 4 (1972), S. 103-113 
    ISSN: 1573-8868
    Schlagwort(e): data processing ; graphics ; statistics ; sedimentology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Results from the application of digital filtering (simple and weighted averaging) to the analysis of sedimentary series are given. Two flysch sequences from the East Carpathians (Upper Eocene, Damacuşa Valley; and Lower Cretaceous, Sbrancani Valley) were studied. Individual components, affecting the conditions of deposition, were separated, and establishment of the geological significance of the components separated by digital filtering was investigated.
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 5 (1973), S. 73-90 
    ISSN: 1573-8868
    Schlagwort(e): allometric equations ; correlation and regression ; principal-components analysis ; statistics ; allometric growth ; ontogeny ; paleontology ; relative growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Relative growth of the Miocene pelecypod Glycymeris parilis (Conrad) was examined using allometric equations and principal components. Different parts of the shell showed contrasting growth strategies that were dictated by functional morphology and basic shell geometry. Despite the divergent developmental strategies, 93 percent of the correlation matrix variance is accounted for by overall size increase. The remaining variance mainly represents growth of the teeth, which differed considerably from other variables.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Mathematical geology 6 (1974), S. 311-332 
    ISSN: 1573-8868
    Schlagwort(e): canonical correlation ; cluster analysis ; correlation ; discriminant analysis ; factor analysis ; multivariate analysis ; numerical taxonomy ; principal coordinates ; regression analysis ; statistics ; allometry ; eurypterids ; integration and coordination ; ontogeny ; paleontology ; relative growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Multivariate analysis is used in the search for one or more types of structure. The statistical zap applies a single method to determine one preselected type of structure. Several zaps suffice to ascertain several types of structure. The statistical shotgun represents an alternative approach. Here, a series of methods is applied to the data with the intent of ascertaining all possible types of structure that may exist. If strong structure is present, an appropriate zap will probably reveal it, and a variety of techniques will determine the same general structure. If only the main structure is required, the zap is adequate. In this situation, the shotgun will display a basic consistency which is at least reassuring. However, zaps may fail to detect a more subtle secondary structure of geological interest which will be displayed by the shotgun. For weakly structured data, a zap will only determine one type of structure but the shotgun reveals all. Study of the ontogeny of Parastylonurus myops(Clarke), a Lower Silurian eurypterid from New York (USA) shows the virtues of the statistical shotgun.
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  • 21
    Digitale Medien
    Digitale Medien
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    Mathematical geology 7 (1975), S. 117-128 
    ISSN: 1573-8868
    Schlagwort(e): data processing ; lognormal theory ; sampling ; simulation ; statistics ; transformations ; economic geology ; mining ; sedimentology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract A logarithmic transformation may be used to improve the efficiency of estimates of the mean when observations follow the lognormal distribution. But if this transformation is applied to observations that follow another distribution, bias may be introduced. We consider some consequences of erroneously applying lognormal estimation theory and demonstrate that biased estimates may be obtained for certain classes of distributions. Illustrations of bias obtained in gold sampling are given.
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  • 22
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    Digitale Medien
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    Mathematical geology 7 (1975), S. 285-293 
    ISSN: 1573-8868
    Schlagwort(e): cluster analysis ; data processing ; orientation data ; statistics ; structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract A method of cluster analysis for orientation data is described. The method enables vector statistics to be applied to polymodal distributions. Similar results to those found by modal analysis are obtained.
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  • 23
    Digitale Medien
    Digitale Medien
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    Mathematical geology 8 (1976), S. 267-282 
    ISSN: 1573-8868
    Schlagwort(e): decomposition ; statistics ; superpositions ; sedimentology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Some of the methods used in the resolution of mixed normal distributions are discussed under three headings: analytical, graphical, and numerical methods. Attention is given to their applicability in the analysis of grain-size data as derived from sieving. Comparisons are made by applying several methods to published data. It is concluded that the numerical methods offer most scope, especially the method of nonlinear least squares. Some analyses of beach sediments, using this method, are presented. The adoption of a convention for the number of individuals in the sample increases ease of interpretation.
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  • 24
    Digitale Medien
    Digitale Medien
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    Mathematical geology 8 (1976), S. 463-475 
    ISSN: 1573-8868
    Schlagwort(e): FORTRAN ; point process ; cluster process ; mutually exciting process ; power-spectrum analysis ; variance time-curve ; likelihood ; log-survivor ; statistics ; time series ; geophysics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Four clustering models are fitted by means of a “spectral-likelihood”method to series of earthquakes in each of 14 seismic regions. It is concluded that from these models only the Neymann—Scott process, containing both short- and long-term components, is satisfactory for all regions. By inspecting the parameters of this model the consistency of results between regions of similar geological type is studied and the characteristics of different types of region are compared.
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  • 25
    Digitale Medien
    Digitale Medien
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    Mathematical geology 3 (1971), S. 135-155 
    ISSN: 1573-8868
    Schlagwort(e): data processing ; plotting ; statistics ; geochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Broken straight lines on probability paper have been proposed as representing the cumulative probability distributions of SiO2, Na, and Cl in certain plutons. This corresponds to pairs of complementarily truncated normal or lognormal distributions. It is shown that alternative representations, such as pairs of overlapping complete normal or lognormal distributions, yield fits equally acceptable statistically if the sample selection is random. The method also yields a good description of distributions described as “complex.” Computer methods of optimizing the free parameters are used; significance testing is discussed in some detail. It is stressed that although significance testing is helpful, it can neither relieve the geochemist of the burden nor take from him the privilege of being independent, and forming his opinion on the total evidence.
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  • 26
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    Mathematical geology 3 (1971), S. 183-192 
    ISSN: 1573-8868
    Schlagwort(e): dimensional analysis ; statistics ; petroleum ; primary migration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract A substantial fraction of sandstones containing commercial quantities of oil are proposed to be in contact with source rocks which produce oil. For these situations the quantity of oil collected in a sandstone is proportional to the area of contact with a source rock of relatively low permeability, rather than to the total thickness of the potential source rock. It is inferred that source rocks along the upper or lower faces of a sandstone should produce more oil into the sandstone than source rocks lateral to the sandstone. Semiquantitative estimates of the thickness or width of required source rock are obtained. The arguments and results are based on published statistical studies and the assumption that a degree of geometrical similarity exists among sandstones.
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  • 27
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    Mathematical geology 4 (1972), S. 235-248 
    ISSN: 1573-8868
    Schlagwort(e): directional data analysis ; new statistical tests ; sampling ; statistics ; orientation data ; paleocurrent analysis ; sedimentology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Statistical procedures for (1) sampling, (2) testing the existence of a preferred direction, and (3) testing homogeneity of twodimensional directional data, which have been developed by the authors for paleocurrent studies, are presented. It is well known that conventional methods of statistical analysis are not applicable to directional data (e.g., crossbedding and ripplemark directions, grain lineations, etc.) which are “circularly distributed” on a compass dial. A sampling technique for directional data has been developed using the circular measures of dispersion and approximate ANOVA of G. S. Watson. On the basis of a pilot survey, it is possible to compute the minimum sample size required for estimating, with a desired precision, the mean paleocurrent direction of a formation. The optimum allocation of sample size between and within outcrops also can be accomplished at a minimum cost. The procedure described for testing uniformity (or lack of preferred direction) is based on the arc lengths made by successive sample points and is simple to use if the sample size is moderate. A table of critical points and a numerical example are given after a description of the test procedure. Finally, the procedures for testing the homogeneity of directional data from several geological formations are described by (1) tests for equality of the resultant directions (polar vectors) and (2) tests for equality of dispersions. With these tests it is possible to determine whether the paleocurrent directions from different geological formations belong to significantly different populations.
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  • 28
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    Mathematical geology 4 (1972), S. 331-343 
    ISSN: 1573-8868
    Schlagwort(e): cross correlation ; mapping ; plotting ; statistics ; stratigraphy ; structure ; electric logging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Manual, semiautomatic, and fully automatic procedures for correlating subsurface data are reviewed. Special emphasis is placed on the use of electric-log data, including that of the dipmeter log, in this discussion. The Holgate method is described for its use in “fine-tuning” or refining gross correlations. A procedure for creating a matrix map for empirically establishing correlation between sets of data is described, and idealized models are shown.
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  • 29
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    Mathematical geology 5 (1973), S. 297-311 
    ISSN: 1573-8868
    Schlagwort(e): statistics ; general geology ; paleontology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract The basic principals of hypothesis testing are reviewed, including the development of the hypothesis, the statistical assumptions made, and the test of the hypothesis. The appropriate experimental design and sampling technique for evaluation of hypotheses posed are discussed. Because the analysis of variance involving the F-test should be used in a wide variety of geological experiments, emphasis is placed on this analysis. Many geological experiments result in the measurement of one or more factors on a continuous scale, whereas others are recorded in a discrete fashion. This necessitates the use of a covariance analysis to evaluate the effect of discrete and continuous factors in the same model. Orthogonal comparisons are discussed as they are used to evaluate specific hypotheses following the general test of hypothesis in the analysis of variance or covariance. All procedures discussed are illustrated using actual palynofloral data.
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  • 30
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    Mathematical geology 5 (1973), S. 377-388 
    ISSN: 1573-8868
    Schlagwort(e): analysis of variance ; regression analysis ; statistics ; sedimentation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract When sample data are divided into groups, and observations consist of the independent variable xand associated dependent variable y,a logical form of analysis is “grouped regression.” This statistical technique allows testing of the relationship between the two variables and assessment of how the relationship is affected by the grouping. A sedimentologic example illustrates the usefulness of such a technique in classifying environments of deposition based on the size of quartz grains and the quartz content.
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  • 31
    ISSN: 1573-8868
    Schlagwort(e): statistics ; general geology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract A procedure is presented for obtaining estimates of components of variance for the main effects and interaction in a two-way factorial arrangement of treatments with only partially cross-classified data (sometimes referred to as unbalanced data in a two-way crossed classification model with interaction). The procedure entails the use of two hierarchical analyses of variance in which each main effect is first treated as classes and then as subclasses. The estimation of the variance component for each main effect results from the solution of two simultaneous equations with values used obtained directly from the hierarchical analyses. The interaction component of variance can be obtained from the variance components for main effects. An example is presented for the purpose of illustrating the procedure. Interpretation of the interaction variance component estimated by the method is limited due to the absence of some of the subclasses.
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  • 32
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    Mathematical geology 6 (1974), S. 219-233 
    ISSN: 1573-8868
    Schlagwort(e): sampling ; simulation ; statistics ; assay weighting ; economic geology ; geochemistry ; mining ; ore-reserve calculations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Weighting of vein assays is desirable where assays represent variable vein widths and variable distances along the vein. The method of weighting used is important in ore-reserve calculations and other investigations. Two possible methods are considered here. The first method, commonly applied in mining, assumes in effect linear variation of assay-width products between assay points. The second method, developed in this paper, assumes linear variation of assays and widths separately. The weighted average assay in an interval dby the second method (aw1, 2)is given by the expression $$a_{w1,2} = V/[(w_1 + w_2 )/2]$$ where $$\begin{gathered} v = (1/3)(\Delta a)(\Delta w)d + (1/2)(\Delta a)w_1 d + (1/2)(\Delta w)a_1 d + a_1 w_1 d \hfill \\ \Delta a = a_2 - a_1 {\text{,}}\Delta w = w_2 - w_1 \hfill \\ \end{gathered} $$ a1, w1 are assay and width at point 1, a2, w2 are assay and width at point 2,and dis the distance between points 1and 2.Statistical testing of the two methods, using 8,913 pairs of copper assay-width data from the Belmont mine area at Butte, suggests the following: within major veins or within veins which show near-linear width variations, the second method may be used with the expectation that the average grade calculated will more closely represent the actual average grade than if the first method were used.
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  • 33
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    Mathematical geology 4 (1972), S. 35-43 
    ISSN: 1573-8868
    Schlagwort(e): data processing ; sampling ; statistics ; mineralogy ; petrology ; sedimentology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Operator error in petrographic point-count analysis introduces bias into the estimates of proportion in a thin section. A correction for this bias, leading to an unbiased estimator of the true proportion in that thin section, is here proposed. Operator error also affects the confidence interval, and in this situation, too, an adjustment is possible. The approach proposed requires that the probabilities associated with operator error, categorized into A-type and B-type errors, are known or assumed. The A-type operator error tends to underestimate the true proportion in a thin section, whereas the B-type operator error tends to overestimate it.
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  • 34
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    Mathematical geology 4 (1972), S. 55-60 
    ISSN: 1573-8868
    Schlagwort(e): frequency distribution ; regression analysis ; statistics ; general geology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract The resolution of mixed frequency distributions into normal components may be accomplished graphically on probability paper. By means of nonlinear regression, a method for such a resolution in the probability net is given and exemplified. It is based on the observed cumulative frequencies.
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  • 35
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    Mathematical geology 8 (1976), S. 349-374 
    ISSN: 1573-8868
    Schlagwort(e): geochemistry ; magmatic rocks ; statistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract A chemical analysis gives a solid base for a study of the distribution of elements in magmatic systems. Development of groups of constituent elements leads to the appearance of regularities which are translated by such close correlations that values for average rock compositions may be calculated using regression lines. These lines are divided into three segments corresponding to granitoids, gabbroids, and dunitoids. This normal geochemical law is not only valid for the average values obtained statistically but also for those obtained from petrographical families resulting from mineralogical classifications. The law also is true for the correlations: Σvalencies/volumes and Σvalencies/theoretical densities. The existence of such a law governing the fundamental geochemical equilibria enables deductions and comparisons to be made with the composition of regional series.
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  • 36
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    Mathematical geology 8 (1976), S. 549-559 
    ISSN: 1573-8868
    Schlagwort(e): cylindrical folds ; orientation data ; statistics ; Bingham's distribution ; structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract An asymptotic form of Bingham's distribution on the sphere is applied to orientation data from cylindrical folds. Data from cylindrical folds typically form two clusters, one cluster for each fold limb. A bimodal distribution is obtained by fitting a unimodal distribution to each cluster. One parameter of the distribution gives the fold axis, another parameter is directly related to the curvature of the fold limb. Certain tests of hypotheses based on this distribution are the same as tests based on the Dimroth—Watson (symmetric girdle)distribution. One such is the test of whether two folds have the same fold axis.
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  • 37
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    Mathematical geology 9 (1977), S. 113-122 
    ISSN: 1573-8868
    Schlagwort(e): statistics ; sedimentology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract A theory of pebble erosion is presented, based on the assumption that the rate of erosion at a point on the surface is a function Vof the curvature there. It is proved that for physically reasonable functions V,the sphere is the only shape of pebble which can maintain its proportions as it wears away. An argument is given which leads to a particular form for the function Vand a few qualitative consequences of this form are indicated. The surface of the pebble at time tmay be described using spherical polar coordinates θ, Φ by the radius function r (θ, Φ, t). This function is given by a highly nonlinear partial differential equation. However, in the case of the erosion of a deformed sphere, when terms which are of second order or higher in the deformation are neglected, the equation becomes linear and is a version of the diffusion equation. The stability of the spherical shape against deformations of the various harmonic types is then easily analyzed.
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  • 38
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    Mathematical geology 9 (1977), S. 245-258 
    ISSN: 1573-8868
    Schlagwort(e): exploration geochemistry ; resource analysis ; statistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Mathematik
    Notizen: Abstract Exploration geochemistry is viewed in a resource appraisal framework and the various general methods are discussed in terms of their applicability at different stages of the appraisal exercise. The direct nature of geochemical exploration is emphasized and the various types of data that the surveys yield are discussed together with their modes of interpretation. It is shown how the data may be simply reduced to a probability form which will allow data from many sources to be utilized. The limitations of exploration geochemistry in resource appraisal are also discussed so that unnatural expectations may not be fostered and that geochemistry be placed correctly, and complementarity, with the other geoscience techniques of resource appraisal.
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  • 39
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    Journal of optimization theory and applications 23 (1977), S. 119-124 
    ISSN: 1573-2878
    Schlagwort(e): Decision theory ; optimal strategies ; probability theory ; search techniques ; statistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract In many nonconvex programming problems, it is possible to locate local optima, but the global optimum may be difficult to determine. In such cases, a search procedure is often used, with random starting solutions, to find alternate local optima. This search can be terminated by a stopping rule, based upon Bayesian revised probability distributions, which determines the optimal number of iterations. The application of this rule to a resource allocation problem in project scheduling is illustrated.
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  • 40
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    Journal of optimization theory and applications 24 (1978), S. 207-220 
    ISSN: 1573-2878
    Schlagwort(e): Stereology ; statistics ; packing problem ; Abel integral equations ; Volterra integral equations ; numerical methods
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract We discuss the application of integral equations techniques to two broad areas of particle statistics, namely, stereology and packing. Problems in stereology lead to the inversion of Abel-type integral equations; and we present a brief survey of existing methods, analytical and numerical, for doing this. Packing problems lead to Volterra equations which, in simple cases, can be solved exactly and, in other cases, need to be solved numerically. Methods for doing this are presented along with some numerical results.
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