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Wyświetlanie 1-15 z 19
Tytuł:
Możliwość zastosowania rozkładów mieszanych do modelowania rozkładów pierśnic drzew w naturalnych klasach biosocjalnych
Potential of mixture distributions application for modelling tree diameter distributions by natural social classes
Autorzy:
Zasada, M.
Powiązania:
https://bibliotekanauki.pl/articles/1026820.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
drzewostany sosnowe
rozklad piersnic
klasy Krafta
lesnictwo
rozklad mieszany
diameter distribution
gamma distribution
mixture distribution
biosocial classes
Opis:
The aim of the presented study was to show an applicability of finite mixture distribution approach for estimating diameter distribution parameters of the dominant and suppressed stands on an example of one-layer, even−aged, pure Scots pine stands. This approach gave a good fit of compound distribution proportions, average d.b.h for the dominant and suppressed stands and standard deviations of d.b.h. for the analysed classes.
Źródło:
Sylwan; 2003, 147, 09; 27-37
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A hybrid statistical approach for texture images classification based on scale invariant features and mixture gamma distribution
Autorzy:
Benlakhdar, Said
Rziza, Mohammed
Thami, Rachid Oulad Haj
Powiązania:
https://bibliotekanauki.pl/articles/29520269.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
statistical image modeling
SIFT
mixture gamma distribution
uniform discrete curvelet transform
classification
Opis:
Image classification refers to an important process in computer vision. The purpose of this paper is to propose a novel approach named GGD-GMM and based on statistical modeling in wavelet domain to describe textured images and rely on number of principles which give its internal coherence and originality. Firstly, we propose a robust algorithm based on the combination of the wavelet transform and Scale Invariant Feature Transform. Secondly, we implement the aforementioned algorithm and fit the result using the finite mixture gamma distribution (GMM). The results, obtained for two benchmark datasets, show that the proposed algorithm has a good relevance as it provides higher classification accuracy compared to some other well known models see (Kohavi, 1995). Moreover, it shows other advantages relied to Noise-resistant and rotation invariant.
Źródło:
Computer Methods in Materials Science; 2020, 20, 3; 95-106
2720-4081
2720-3948
Pojawia się w:
Computer Methods in Materials Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena zgodności rozkładów empirycznych pierśnic drzewostanów bukowych różnych klas wieku z wybranymi rozkładami teoretycznymi
Goodness of fit evaluation of the breast height diameter distributions of beech stands differing in age with selected theoretical distributions
Autorzy:
Jagiełło, R.
Beker, C.
Jagodziński, A.M.
Powiązania:
https://bibliotekanauki.pl/articles/989389.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
drzewostany bukowe
klasy wieku
buk zwyczajny
Fagus sylvatica
piersnice drzew
rozklad empiryczny
rozklad teoretyczny
ocena zgodnosci
diameter distribution
finite mixture distribution
beech stand
fagus sylvatica
Opis:
Modelling is one of the basic activities in the field of biological sciences. The main purpose of modelling is to illustrate relationships and phenomena of biological objects (and traits describing them) and present reality as close as it is possible with expected range of error. In the paper we presented results of approximation of the selected theoretical distributions, i.e. singular (normal, log−normal, gamma, two− and three−parameter Weibull, Johnsons SB) and finite mixture (normal, log−normal, gamma and Weibull) to tree diameter distributions in beech stands (Fagus sylvatica L.). The main aim of the study was to evaluate goodness of fit of selected distributions, prove legitimacy of using mixture distributions in even−aged, single−species beech stands and find the best distribution of model diameter distribution in a whole production cycle of this kind of stands. The study was conducted in 32 sample plots located in north−western Poland in stands at the age between 9 and 140. For the evaluation χ² test, a modified error index (e) and a root mean square error (RMSE) were used. We found that the RMSE and e are related in most cases with stand density. Mean values of used indicators show that finite mixture distributions are better in comparison to singular distributions. The best fitted distributions were Johnsons SB and mixture of gamma ones. Range of error index expressed with number of trees per hectare ranges 16.5−32.8% and 7.7−27.0% for this distributions, respectively. Conversely the worst results were obtained by fitting two−parameter Weibull distribution both in singular and mixture. Future diameter distribution model based on the probability distribution should be based on Johnson SB or 3−parameter Weibull distribution from singular ones or gamma from finite mixture. In case of age class apportionment unequivocal the best result were obtained with Johnson SB and partially with mixture gamma distributions.
Źródło:
Sylwan; 2016, 160, 02; 107-119
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On functional measures of skewness
Autorzy:
Dziubińska, Renata
Szynal, Dominik
Powiązania:
https://bibliotekanauki.pl/articles/1340223.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
mean
standard deviation
mixture of distribution functions
quantiles
conditional distributions
Pareto distributions
the Pearson coefficient of skewness
median
Opis:
We introduce a concept of functional measures of skewness which can be used in a wider context than some classical measures of asymmetry. The Hotelling and Solomons theorem is generalized.
Źródło:
Applicationes Mathematicae; 1995-1996, 23, 4; 395-403
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On monotone dependence functions of the quantile type
Autorzy:
Krajka, Andrzej
Szynal, Dominik
Powiązania:
https://bibliotekanauki.pl/articles/1340380.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
associated random variables
quantile monotone dependence function
mixture of distribution functions
quantile
independent
positively (negatively) quadrant dependent random variables
monotone dependence function
Opis:
We introduce the concept of monotone dependence function of bivariate distributions without moment conditions. Our concept gives, among other things, a characterization of independent and positively (negatively) quadrant dependent random variables.
Źródło:
Applicationes Mathematicae; 1995-1996, 23, 1; 51-72
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On SαS density function
Autorzy:
Mazurkiewicz, Grażyna
Powiązania:
https://bibliotekanauki.pl/articles/729728.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
stable distribution
symmetric stable distribution
moments
scale mixture
Opis:
In this paper, we study some analytical properties of the symmetric α-stable density function.
Źródło:
Discussiones Mathematicae Probability and Statistics; 2005, 25, 1; 91-101
1509-9423
Pojawia się w:
Discussiones Mathematicae Probability and Statistics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sum of gamma and normal distribution
Autorzy:
Sitek, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1931403.pdf
Data publikacji:
2020
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
mixture of probability distribution
statistical auditing
sum of gamma and normal distribution
accounting error
mieszanka rozkładu prawdopodobieństwa
audyt statystyczny
suma rozkładu gamma i normalnego
błąd księgowy
Opis:
Purpose: The article shows how to model audit errors using mixtures of probability distribution. Design/methodology/approach: In financial accounting, data about the economic activities of a given firm is collected and then summarized and reported in the form of financial statements. Auditing, on the other hand, is the independent verification of the fairness of these financial statements. An item in an audit sample produces two pieces of information: the book (recorded) amount and the audited (correct) amount. The difference between the two is called the error amount. The book amounts are treated as values of a random variable whose distribution is a mixture of the distributions of the correct amount and the true amount contaminated by error. The mixing coefficient is equal to the proportion of the items with non-zero errors amounts. Findings: The sum of normal and gamma distribution can be useful for modeling audit errors. Originality/value: In this paper, the method of moments is proposed to estimate mixtures of probability distribution, and we derive a formulation of the probability distribution of the sum of a normally distributed random variable and one with gamma distribution. This research could be useful in financial auditing.
Źródło:
Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska; 2020, 143; 275-284
1641-3466
Pojawia się w:
Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of changes in the distribution of income in the Czech Republic using mixture models
Autorzy:
Malá, Ivana
Powiązania:
https://bibliotekanauki.pl/articles/433957.pdf
Data publikacji:
2013
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
income distributions
maximum likelihood estimate
finite mixture
lognormal distribution
Dagum distribution
Opis:
In the text the development of distributions (and their characteristics) of the equivalised net annual nominal income in Czech households in 2004-2009 is studied. Three-parametric lognormal and Dagum distributions are used as a model for income probability distribution. Moreover, finite mixtures of these distributions are estimated for the models with an observable component membership (given by the number of economically active members of the household and the number of unemployed members). Data from the European Union survey – Statistics on Income and Living Conditions 2005-2010 – are used for the analysis. All the estimates in the text are obtained using the maximum likelihood method.
Źródło:
Śląski Przegląd Statystyczny; 2013, 11(17); 137-150
1644-6739
Pojawia się w:
Śląski Przegląd Statystyczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison study on a new five-parameter generalized Lindley distribution with its sub-models
Autorzy:
Tharshan, Ramajeyam
Wijekoon, Pushpakanthie
Powiązania:
https://bibliotekanauki.pl/articles/1363562.pdf
Data publikacji:
2020-06-05
Wydawca:
Główny Urząd Statystyczny
Tematy:
Lindley distribution
mixture distributions
size-biased distributions
maximum likelihood estimation
Opis:
In recent years, modifications of the classical Lindley distribution have been considered by many authors. In this paper, we introduce a new generalization of the Lindley distribution based on a mixture of exponential and gamma distributions with different mixing proportions and compare its performance with its sub-models. The new distribution accommodates the classical Lindley, Quasi Lindley, Two-parameter Lindley, Shanker, Lindley distribution with location parameter, and Three-parameter Lindley distributions as special cases. Various structural properties of the new distribution are discussed and the size-biased and the lengthbiased are derived. A simulation study is conducted to examine the mean square error for the parameters by means of the method of maximum likelihood. Finally, simulation studies and some real-world data sets are used to illustrate its flexibility in terms of its location, scale and shape parameters.
Źródło:
Statistics in Transition new series; 2020, 21, 2; 89-117
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Loss modeling with mixtures distributions in R package
Autorzy:
Sitek, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/434037.pdf
Data publikacji:
2017
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
finite mixture of distributions
loss distribution
maximum likelihood estimate
EM algorithm
Opis:
Finite mixtures of probability distributions may be successfully used in the modeling of probability distributions of losses. These distributions are typically heavy tailed and positively skewed. Finding the distribution that fits loss data well is often difficult. The paper shows that the use of mixed models can significantly improve the goodness-of-fit of the loss data. The paper also presents an algorithm to find estimates of parameters of mixture distribution and gives an illustrative example. The analytical approach is probably the most often used in practice and certainly the most frequently adopted in the actuarial literature. It is reduced to finding a suitable analytical expression which fits the observed data well. For parameters estimation we use the maximum likelihood method applying the Newton-Raphson and EM algorithm. Computations of goodness-of-fit can be judged using the Akaike information criterion.
Źródło:
Śląski Przegląd Statystyczny; 2017, 15 (21); 183-200
1644-6739
Pojawia się w:
Śląski Przegląd Statystyczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of a class of lifetime distributions
Autorzy:
Knopik, L.
Powiązania:
https://bibliotekanauki.pl/articles/969965.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
ageing classes
IFR
IFRA
NBUE
MTER
HNBUE
convolution
limit distribution
mixture
Opis:
In Knopik (2005) the ageing class MTFR (Mean Time to Failure or Repair) of lifetime distribution was introduced. In this paper, we show that the family MTFR is closed under weak convergence of distribution and convolution. We prove that the dual family MTFR^D (in a particular case) is closed under mixtures.
Źródło:
Control and Cybernetics; 2006, 35, 2; 407-414
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Estimation of Bi‑liner Regression Parameters
O estymacji parametrów bi‑prostych
Autorzy:
Sitek, Grzegorz Antoni
Wywiał, Janusz Leszek
Powiązania:
https://bibliotekanauki.pl/articles/659252.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
bi proste
regresja
metoda najmniejszych kwadratów dla zależności niejawnych
mieszanki rozkładów prawdopodobieństwa
bi lines function
linear regression
least squares method for an implicit interdependence
mixture of probability distribution
Opis:
W artykule rozważano problem estymacji parametrów bi‑prostych, które z geometrycznego punktu widzenia są dwiema przecinającymi się prostymi. Za pomocą tzw. metody najmniejszych kwadratów dla zależności niejawnych wyznaczono przybliżone wartości estymatorów parametrów bi‑prostych. W szczególnym przypadku wyznaczono dokładne wzory na estymatory parametrów, dowodząc ich łącznej asymptotycznej normalności rozkładu prawdopodobieństwa. Ponadto analizowano związki między bi‑prostymi oraz liniowymi regresjami rozkładów prawdopodobieństwa, które są składowymi mieszanki dwuwymiarowych rozkładów prawdopodobieństw. W wyniku symulacyjnych eksperymentów wykazano, że brane pod uwagę zgodne estymatory parametrów bi‑prostych dają jednak obciążone estymatory parametrów regresji rozkładów będących składowymi mieszanki dwuwymiarowych rozkładów prawdopodobieństwa.
Two non‑parallel lines will be named as bi‑lines. The relationship between the definition of the bi‑lines function and linear regression functions of the distribution mixture is considered. The bi‑lines function parameters are estimated using the least squares method for an implicit interdependence. In general, values of parameter estimators are evaluated by means of an approximation numerical method. In a particular case, the exact expressions for the parameter estimators were derived. In this particular case, the properties of the estimators are examined in details. The bi‑lines are also used to estimate the regression functions of the distribution mixture. The accuracy of the parameter estimation is analyzed.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2017, 6, 332; 87-98
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling income on the basis of distribution mixture
Autorzy:
Sitek, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/584955.pdf
Data publikacji:
2014
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
finite mixture
income distribution
maximum likelihood estimate
EM algorithm
number of components
Opis:
Finite mixtures of probability distributions may be successfully used in the modeling of probability distributions of incomes. These distributions are typically heavy tailed and positively skewed. This article deals with the problem of determining the number of components in mixture modeling. This paper considers the likelihood of ratio-based testing of the null hypothesis of homogeneity in mixture models. The number of components is an important parameter in the applications of finite mixture models.
Źródło:
Mathematical Economics; 2014, 10(17); 79-90
1733-9707
Pojawia się w:
Mathematical Economics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of wood-derived biochar on the hydraulic characteristics of compacted soils: Its influence on simulated farmland carbon sequestration
Autorzy:
Ahmed, A.
Kurian, J.
Satyanarayana, S.
Raghavan, V.
Powiązania:
https://bibliotekanauki.pl/articles/2083067.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
soil biochar mixture
water retention
pore-size
distribution
hydraulic conductivity
carbon sequestration
Opis:
The addition of biochar is often proposed to increase agricultural soil quality and crop yield, while at the same time sequestering carbon from the atmosphere to help mitigate global climate change. In this research, the pore-size distribution, and saturated hydraulic conductivity of sandy loam and clay loam soils amended with varying dosages (0-10% dry basis) and two different particle sizes (0.5-420 μm (PS1) or 421-841 μm (PS2)) of wood-derived biochar were investigated under compacted conditions (5, 10, or 15 standard Proctor rammer blows (5B, 10B, or 15B, respectively)). In the 5B compacted SL (SL-5B) soil, the volume of the soil fissures and transmission pores decreased, while the volume of the storage pores (SP) increased with increasing wood-derived biochar dosage. 23.1±0.9% of the volume of the 5B compacted clay loam (CL-5B) are storage pores, this value increased to 27.4±2.0% upon amendment with 10% PS1. The saturated hydraulic conductivity of the sandy loam-5B soil amended with 10% PS1 decreased from 6.8±0.3 to 0.80±0.03 mm h-1. The sandy loam farmland C emissions decreased by 0.071 tC ha-1 y-1, whereas CL farmland C emissions decreased by 0.091 tC ha-1 y-1.
Źródło:
International Agrophysics; 2021, 35, 2; 167-177
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extended Lognormal Distribution: Properties and Applications
Autorzy:
Lahcene, Bachioua
Powiązania:
https://bibliotekanauki.pl/articles/1030771.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Characteristics and Survival Function
Generating and Quantile Functions
Hazard Rate Function
Lognormal Distribution
Mixture
Model
Opis:
This paper is devoted to study a form of lognormal distributions family and introduce some of its basic properties. It presents new derivate models that find many applications will be useful for practitioners in various fields. The abstract explores some of the basic characteristics of the family of abnormal distributions and provides some practical methods for analyzing some different applied fields related to theoretical and applied statistical sciences. The proposed model allows for the improvement of the relevance of near-real data and opens broad horizons for the study of phenomena that can be addressed through the results obtained. This study is devoted to a review of fitting data, discuss distribution laws for models and describe the approaches used for parameterization and classification of models. Finally, a set of concluding observations has been developed to track the mix distributions and their adaptation mechanisms.
Źródło:
World Scientific News; 2020, 145; 16-30
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 19

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