نتایج جستجو برای: and exponential variograms

تعداد نتایج: 16835200  

Journal: :FEMS microbiology ecology 2004
Erik A Lilleskov Thomas D Bruns Thomas R Horton D Taylor Paul Grogan

Ectomycorrhizal fungal (EMF) communities are highly diverse at the stand level. To begin to understand what might lead to such diversity, and to improve sampling designs, we investigated the spatial structure of these communities. We used EMF community data from a number of studies carried out in seven mature and one recently fire-initiated forest stand. We applied various measures of spatial p...

2011
J. GIBERGANS-BAGUENA M. I. ORTEGO R. TOLOSANA-DELGADO

The aim of this paper is to introduce a methodology for defining groups from regionalized compositional data, through a hierarchical clustering algorithm aware of both the spatial dependence and the compositional character of the data set. This method is used to define a regionalization of Catalunya (NE Spain) with respect to its precipitation patterns in the Winter season. This region is chara...

Journal: :journal of mathematical modeling 0
amir sadeghi department of mathematics, islamic azad university, robat karim branch, tehran, iran maryam shams solary department of mathematics, payame noor university, p.o. box 19395-3697, tehran, iran

it is well known that the matrix exponential function has practical applications in engineering and applied sciences. in this paper, we present some new explicit identities to the exponential functions of a special class of matrices that are known as central-symmetric $x$-form. for instance, $e^{mathbf{a}t}$, $t^{mathbf{a}}$ and $a^{mathbf{a}t}$ will be evaluated by the new formulas in this par...

Abstract. In this work, it has been shown that the combined use of exponential operators and integral transforms provides a powerful tool to solve time fractional generalized KdV of order 2q+1 and certain fractional PDEs. It is shown that exponential operators are an effective method for solving certain fractional linear equations with non-constant coefficients. It may be concluded that the com...

A. Naderi, D. A. S. Fraser, Jie Su, Kexin Ji, Wei Lin,

Welch & Peers (1963) used a root-information prior to obtain posterior probabilities for a scalar parameter exponential model and showed that these Bayes probabilities had the confidence property to second order asymptotically. An important undercurrent of this indicates that the constant information reparameterization provides location model structure, for which the confidence property ...

Journal: :ISPRS Int. J. Geo-Information 2016
Chunmei Wang Qinke Yang David Laurence Barry Jupp Guowei Pang

Abstract: In this paper, the way topographic spatial information changes with resolution was investigated using semi-variograms and an Independent Structures Model (ISM) to identify the mechanisms involved in changes of topographic parameters as resolution becomes coarser or finer. A typical Loess Hilly area in the Loess Plateau of China was taken as the study area. DEMs with resolutions of 2.5...

2013
Asmatullah Chaudhry Jin Young Kim Tran Anh Tuan

In this paper, we perform an experimental study to investigate directional variograms in punctual kriging and consequently its effect on image restoration. We employ punctual kriging in conjunction with fuzzy logic typeII and fuzzy smoothing based approaches to remove white Gaussian noise from corrupted images. Images degraded with Gaussian white noise are restored by first utilizing fuzzy logi...

Journal: :journal of agricultural science and technology 2011
h. hamzehzarghani s. a. kazemeini

the performance of different yield loss models from an exponential family was evaluated in safflower-redroot pigweed systems in two field experiments conducted during 2007 and 2008 growing seasons at the research field of agricultural college of shiraz university, iran. the yield loss of safflower was recorded as relative yield loss in experimental plots laid out in split plot design with three...

1997
Wendy Meiring Peter Guttorp Paul D. Sampson

Many environmental processes are heterogeneous in space (spatially non-stationary), due to factors such as topography, local pollutant emissions, and meteorology. Much of the commonly used spatial statistical methodology depends on simplifying assumptions such as spatial isotropy. Violations of these assumptions can cause problems, including incorrect error assessment of spatial estimates. This...

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