scholarly journals Distribution Inference for Physical and Orbital Properties of Jupiter’s Moons

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
F. B. Gao ◽  
X. H. Zhu ◽  
X. Liu ◽  
R. F. Wang

According to the physical and orbital characteristics in Carme group, Ananke group, and Pasiphae group of Jupiter’s moons, the distributions of physical and orbital properties in these three groups are investigated by using one-sample Kolmogorov–Smirnov nonparametric test. Eight key characteristics of the moons are found to mainly obey the Birnbaum–Saunders distribution, logistic distribution, Weibull distribution, and t location-scale distribution. Furthermore, for the moons’ physical and orbital properties, the probability density curves of data distributions are generated; the differences of three groups are also demonstrated. Based on the inferred results, one can predict some physical or orbital features of moons with missing data or even new possible moons within a reasonable range. In order to better explain the feasibility of the theory, a specific example is illustrated. Therefore, it is helpful to predict some of the properties of Jupiter’s moons that have not yet been discovered with the obtained theoretical distribution inference.

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Emrah Dokur ◽  
Salim Ceyhan ◽  
Mehmet Kurban

To construct the geometry in nonflat spaces in order to understand nature has great importance in terms of applied science. Finsler geometry allows accurate modeling and describing ability for asymmetric structures in this application area. In this paper, two-dimensional Finsler space metric function is obtained for Weibull distribution which is used in many applications in this area such as wind speed modeling. The metric definition for two-parameter Weibull probability density function which has shape (k) and scale (c) parameters in two-dimensional Finsler space is realized using a different approach by Finsler geometry. In addition, new probability and cumulative probability density functions based on Finsler geometry are proposed which can be used in many real world applications. For future studies, it is aimed at proposing more accurate models by using this novel approach than the models which have two-parameter Weibull probability density function, especially used for determination of wind energy potential of a region.


FLORESTA ◽  
2004 ◽  
Vol 34 (3) ◽  
Author(s):  
Alexandra Consuelo De Plácido e Silva Bartoszeck ◽  
Sebastião Do Amaral Machado ◽  
Afonso Figueiredo Filho ◽  
Edilson Batista Oliveira

Esta pesquisa tem como objetivo estudar o comportamento de funções de densidade probabilística no ajuste de distribuições diamétricas para diferentes idades, sítios e densidades para povoamentos de bracatinga (Mimosa scabrella Benth) localizados nos municípios da Região Metropolitana de Curitiba, PR. Os dados utilizados são provenientes de um experimento delineado em blocos ao acaso, constituído de 5 blocos e 4 tratamentos, perfazendo um total de 20 parcelas, as quais foram remedidas 4 vezes às idades aproximadas de 4, 5, 6 e 7,5 anos de idade. A densidade inicial foi reduzida para 2000, 4000, 8000 árvores por hectare, sendo que as testemunhas não sofreram nenhum tratamento. Desses cinco blocos, um estava localizado na classe de sítio I, dois na classe II e dois na classe III. Paralelamente, foram instaladas e medidas 124 parcelas temporárias, distribuídas nos vários municípios da Região Metropolitana, representando os povoamentos de bracatinga sob o regime tradicional de cultivo e manejo, abrangendo as idades de 3 a 18 anos e as 3 classes de sítio. As seguintes funções de densidade probabilística foram ajustadas para cada combinação de idade, sítio e densidade: Normal, Lognormal, Gama, Beta, Weibull 2 parâmetros, Weibull 3 parâmetros e a SB de Johnson. Através do teste “D” de Kolmogorov-Smirnov detectou-se que a função SB de Johnson foi a de melhor desempenho para a maioria das combinações de dados, sendo, portanto, a primeira no ranking. Os índices de simetria e curtose indicaram que as curvas de distribuições diamétricas em bracatingais são unimodais, tornando-se cada vez mais assimétricas positivas e mais achatadas com o avanço da idade. DIAMETER DISTRIBUTION FOR STANDS OF Mimosa scabrella FOR DIFFERENT AGES, SITES AND DENSITIES Abstract The objective of this research work was to study the behavior of several probability density functions in fitting the diameter distribution for different ages, sites and densities for stands of bracatinga (Mimosa scabrella Benth) located in the Curitiba metropolitan region. The utilized data came from an initial density trial, designed in random blocks, formed by 5 blocks and 4 treatments, in a total of 20 permanent sample plots with an area of 325 m2, which were remeasured 4 times at approximate ages of 4, 5, 6 and 7,5 years. The initial density was reduced for 2000, 4000, 8000 trees per hectare, remaining the control plots without any reduction of trees. From these five blocks, one was located on site class I, two on site class II and two blocks on site class III. Simultaneously they were also implanted and measured diameters and heights of every tree in 124 temporary sample plots (325 m2) scattered by several counties of the Curitiba metropolitan region, on stands that represent the traditional way of cultivation and management of bracatinga. These plots covered ages from 3 to 18 years and the 3 sites classes. Seven probability density functions were tested to fit the diameter distribution: Normal, Lognormal, Gama, Beta, Weibull 2 parameters, Weibull 3 parameters and the SB from Johnson. The combination of sites, densities and ages for the permanent and the temporary sample plots with these seven functions made it possible to accomplish 434 analysis. The Kolmogorov-Smirnov test was applied for every analysis for the choice of the best function. The Jonhson’s SB function was the one that presented the best performance, being so, used for the construction of the diameter distribution curves. The asymmetry and Kurtosis indexes indicated that the curves of diameter distributions in bracatinga stands are unimodal, as hypothesized, becoming more and more asymmetric positively and more flattened as the stands become older.


2016 ◽  
Vol 5 (2) ◽  
pp. 78 ◽  
Author(s):  
Zohdy M. Nofal ◽  
Ahmed Z. Afify ◽  
Haitham M. Yousof ◽  
Daniele C. T. Granzotto ◽  
Francisco Louzada

This paper introduces a new lifetime model which is a generalization of the transmuted exponentiated additive Weibull distribution by using the Kumaraswamy generalized (Kw-G) distribution. With the particular case no less than \textbf{seventy nine} sub models as special cases, the so-called Kumaraswamy transmuted exponentiated additive Weibull distribution, introduced by Cordeiro and de Castro (2011) is one of this particular cases. Further, expressions for several probabilistic measures are provided, such as probability density function, hazard function, moments, quantile function, mean, variance and median, moment generation function, R\'{e}nyi and q entropies, order estatistics, etc. Inference is maximum likelihood based and the usefulness of the model is showed by using a real dataset.


2020 ◽  
Vol 27 (2) ◽  
pp. 8-15
Author(s):  
J.A. Oyewole ◽  
F.O. Aweda ◽  
D. Oni

There is a crucial need in Nigeria to enhance the development of wind technology in order to boost our energy supply. Adequate knowledge about the wind speed distribution becomes very essential in the establishment of Wind Energy Conversion Systems (WECS). Weibull Probability Density Function (PDF) with two parameters is widely accepted and is commonly used for modelling, characterizing and predicting wind resource and wind power, as well as assessing optimum performance of WECS. Therefore, it is paramount to precisely estimate the scale and shape parameters for all regions or sites of interest. Here, wind data from year 2000 to 2010 for four different locations (Port Harcourt, Ikeja, Kano and Jos) were analysed and the Weibull parameters was determined. The three methods employed are Mean Standard Deviation Method (MSDM), Energy Pattern Factor Method (EPFM) and Method of Moments (MOM) for estimating Weibull parameters. The method that gave the most accurate estimation of the wind speed was MSDM method, while Energy Pattern Factor Method (EPFM) is the most reliable and consistent method for estimating probability density function of wind. Keywords: Weibull Distribution, Method of Moment, Mean Standard Deviation Method, Energy Pattern Method


1978 ◽  
Vol 1 (16) ◽  
pp. 33 ◽  
Author(s):  
Theodore T. Lee ◽  
Kerry P. Black

The transformation of waves crossing a coral reef in Hawaii including the probability density function of the wave heights and periods and the shape of the spectrum is discussed. The energy attenuation and the change of height and period statistics is examined using spectral analysis and the zero up-crossing procedure. Measurements of waves at seven points along a 1650 ft transect in depths from 1 to 3.5 ft on the reef and 35 ft offshore were made. The heights were tested for Rayleigh, truncated Rayleigh and Wei bull distributions. A symmetrical distribution presented by Longuet-Higgins (1975) and the Weibull distribution were compared to the wave period density function. In both cases the Weibull probability density function fitted with a high degree of correlation. Simple procedures to obtain Weibull coefficients are given. Fourier spectra were generated and contours of cumulative energy against each position on the reef show the shifting of energy from the peak as the waves move into shallow water. A design spectrum, with the shape of the Weibull distribution, is presented with procedures given to obtain the coefficients which govern the distribution peakedness. Normalized non-dimensional frequency and period spectra were recommended for engineering applications for both reef and offshore locations. A zero up-crossing spectrum (ZUS) constructed from the zero upcrossing heights and periods is defined and compared with the Fourier spectrum. Also discussed are the benefits and disadvantages of the ZUS, particularly for non-linear wave environments in shallow water. Both the ZUS and Fourier spectra are used to test the adequacy of formulae which estimate individual wave parameters. Cross spectra analysis was made to obtain gain function and squared coherency for time series between two adjacent positions. It was found that the squared coherency is close to unity near the peak frequency. This means that the output time series can be predicted from the input by applying the gain function. However, the squared coherency was extremely small for other frequencies above 0.25 H2.


2012 ◽  
Vol 3 (1) ◽  
Author(s):  
Christopher H. Rhoads

Policy analysts involved in quantitative research have many options for handling missing data. The method chosen will often greatly influence the substantive policy conclusions that will be drawn from the data. The most frequent methods for handling missing data assume that the data are missing at random (MAR). The current paper notes that an omnibus, nonparametric test of the MAR assumption is impossible using the observed data alone. Nonetheless various purported tests of the missingness mechanism (including tests of MAR) appear in the literature. The current paper clarifies that all of these tests rely on some assumption that cannot be tested from the data. The paper notes that tests of the missingness mechanism are frequently misinterpreted and it clarifies the appropriate interpretation of such tests. Policy analysts are encouraged not to develop the false impression that modern procedures for handling missing data in conjunction with tests of the missingness mechanism provide protection against the ill effects of missing data. Any justification for a particular approach to handling missing data must be come from substantive knowledge of the missingness process, not from the data.


FLORESTA ◽  
2012 ◽  
Vol 42 (4) ◽  
pp. 741 ◽  
Author(s):  
Saulo Jorge Téo ◽  
Júlio César Bianchi ◽  
Adriano Peloso ◽  
Paulo Roberto Nava ◽  
Alan Marcon ◽  
...  

ResumoO objetivo deste trabalho foi analisar as funções de densidade probabilísticas (FDP) Normal, Ln-Normal, Sb de Johnson, Weibull 3P, Gamma, Beta e Weber, para descrever as mudanças na estrutura diamétrica de povoamentos de Pinus taeda L., na região de Caçador (SC), em diferentes idades e classes de sítio. O processamento dos dados foi realizado por meio da ferramenta Solver, do software MS Excel 2010, a qual utiliza o algoritmo linear de gradiente reduzido generalizado (GRG) na interação dos parâmetros. Verificou-se que a FDP Sb de Johnson e Weibull 3 P apresentaram os melhores desempenhos. Para a avaliação da aderência das FDP, é recomendada a utilização das estatísticas R2, R2aj, syx e syx%, além do teste de Kolmogorov-Smirnov, em todos os casos, especialmente quando houver número de observações superior a 5.000. Geralmente, houve um aumento da amplitude dos valores dos diâmetros e um achatamento da distribuição diamétrica com o avanço da idade e com a melhora da produtividade do sítio. Com o progresso da idade, há um aumento dos valores do diâmetro máximo e do diâmetro modal das distribuições, para as classes de sítio de maior produtividade, porém o mesmo não ocorre para o sítio menos produtivo. AbstractPerformance of probability density functions in order to describe diameter distribution of Pinus taeda, in the region of Caçador, SC. This research aims to analyze probability of density functions (pdf) Normal, Ln-Normal, Johnson Sb, 3 P Weibull, Gamma, Beta and Weber in order to describe  diameter changes in Pinus taeda L. plantations structure, in the region of Caçador - SC, Brazil, at different age and site classes. The data processing was carried out by Solver tool of the software MSExcel2010, using the linear algorithm of generalized reduced gradient (GRG) for interaction of parameters. As result, Johnson Sb and 3PWeibull presented the best performances. For the pdf adherence evaluation, it was recommended the employment of R2, R2aj, syx e syx% statistics, besides the Kolmogorov-Smirnov test, in any situation, specially, when there is more than 5,000 observations. Generally, there was an increasing in the range of diameter values and a flatness of diameter distribution at advancing age and improvement of the site productivity. At age advancing, there was an increasing of maximum diameter and modal diameter values of distributions, for the higher productivity site classes, on the other hand, the same did not occur for the low productivity site class.Keywords: Horizontal structure; Kolmogorov-Smirnov test; probability density function; forestry site.


2017 ◽  
Vol 91 (6) ◽  
pp. 1296-1305 ◽  
Author(s):  
Hui-ting Wu ◽  
G. R. Shi ◽  
Wei-hong He

AbstractTwo middle Permian (Capitanian) to Early Triassic (Griesbachian) rugosochonetidae brachiopod genera, Fusichonetes Liao in Zhao et al., 1981 and Tethyochonetes Chen et al., 2000, have been regarded as two distinct taxa and used as such for a wide range of discussions including biostratigraphy, paleoecology, paleobiogeography, and the Permian-Triassic boundary mass extinction. However, the supposed morphological distinctions between the two taxa are subtle at best and appear to represent two end members of a continuum of morphological variations. In this study, we applied a range of quantitative and analytical procedures (bivariate plots, Kolmogorov-Smirnov test, categorical principle component analysis, and cladistic analysis) to a dataset of 15 quantified morphological variables, integrating both key external and internal characters, measured from 141 specimens of all well-known Fusichonetes and Tethyochonetes in order to test whether or not these two genera could be distinguished in view of the chosen characters. The results indicate that these two genera are morphologically indistinguishable and that the species classification previously applied to these two genera appears to represent polyphyletic groupings within the genus Fusichonetes. Consequently, Tethyochonetes is concluded to be a junior synonym of Fusichonetes. The diagnosis and key characteristics of Fusichonetes are clarified and refined based on a new suite of well-preserved specimens from the Permian−Triassic Xinmin section in South China.


2021 ◽  
Vol 26 (3) ◽  
pp. 62
Author(s):  
Zichuan Mi ◽  
Saddam Hussain ◽  
Christophe Chesneau

In recent advances in distribution theory, the Weibull distribution has often been used to generate new classes of univariate continuous distributions. They find many applications in important disciplines such as medicine, biology, engineering, economics, informatics, and finance; their usefulness is synonymous with success. In this study, a new Weibull-generated-type class is presented, called the weighted odd Weibull generated class. Its definition is based on a cumulative distribution function, which combines a specific weighted odd function with the cumulative distribution function of the Weibull distribution. This weighted function was chosen to make the new class a real alternative in the first-order stochastic sense to two of the most famous existing Weibull generated classes: the Weibull-G and Weibull-H classes. Its mathematical properties are provided, leading to the study of various probabilistic functions and measures of interest. In a consequent part of the study, the focus is on a special three-parameter survival distribution of the new class defined with the standard exponential distribution as a reference. The exploratory analysis reveals a high level of adaptability of the corresponding probability density and hazard rate functions; the curves of the probability density function can be decreasing, reversed N shaped, and unimodal with heterogeneous skewness and tail weight properties, and the curves of the hazard rate function demonstrate increasing, decreasing, almost constant, and bathtub shapes. These qualities are often required for diverse data fitting purposes. In light of the above, the corresponding data fitting methodology has been developed; we estimate the model parameters via the likelihood function maximization method, the efficiency of which is proven by a detailed simulation study. Then, the new model is applied to engineering and environmental data, surpassing several generalizations or extensions of the exponential model, including some derived from established Weibull-generated classes; the Weibull-G and Weibull-H classes are considered. Standard criteria give credit to the proposed model; for the considered data, it is considered the best.


2014 ◽  
Vol 11 (1) ◽  
Author(s):  
Felix Nwobi ◽  
Chukwudi Ugomma

In this paper we study the different methods for estimation of the parameters of the Weibull distribution. These methods are compared in terms of their fits using the mean square error (MSE) and the Kolmogorov-Smirnov (KS) criteria to select the best method. Goodness-of-fit tests show that the Weibull distribution is a good fit to the squared returns series of weekly stock prices of Cornerstone Insurance PLC. Results show that the mean rank (MR) is the best method among the methods in the graphical and analytical procedures. Numerical simulation studies carried out show that the maximum likelihood estimation method (MLE) significantly outperformed other methods.


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