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  • 1975-1979  (15)
  • Geosciences  (15)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 8 (1976), S. 627-634 
    ISSN: 1573-8868
    Keywords: numerical analysis ; statistics ; mining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 7 (1975), S. 129-147 
    ISSN: 1573-8868
    Keywords: correlation ; factor analysis ; regression analysis ; statistics ; allometric growth ; paleontology ; relative growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 9 (1977), S. 455-481 
    ISSN: 1573-8868
    Keywords: statistics ; earthquake prediction ; fracture mechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 10 (1978), S. 73-90 
    ISSN: 1573-8868
    Keywords: paleoecology ; sampling ; statistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 10 (1978), S. 169-193 
    ISSN: 1573-8868
    Keywords: autocorrelation ; sampling ; statistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 10 (1978), S. 141-167 
    ISSN: 1573-8868
    Keywords: geomorphology ; statistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 8 (1976), S. 9-23 
    ISSN: 1573-8868
    Keywords: cluster analysis ; statistics ; numerical taxonomy ; structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 7 (1975), S. 117-128 
    ISSN: 1573-8868
    Keywords: data processing ; lognormal theory ; sampling ; simulation ; statistics ; transformations ; economic geology ; mining ; sedimentology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 7 (1975), S. 285-293 
    ISSN: 1573-8868
    Keywords: cluster analysis ; data processing ; orientation data ; statistics ; structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 8 (1976), S. 267-282 
    ISSN: 1573-8868
    Keywords: decomposition ; statistics ; superpositions ; sedimentology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: 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.
    Type of Medium: Electronic Resource
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