ABSTRACT In survival analysis applications, the presence of failure rate functions with non monot... more ABSTRACT In survival analysis applications, the presence of failure rate functions with non monotone shapes is common. Therefore, models that can accommodate such different shapes are needed. In this article, we present a location regression model based on the complementary exponentiated exponential geometric distribution as an alternative to the usual bathtub, increasing, and decreasing failure rates in lifetime data. Assuming censored data, we consider the maximum likelihood inference for analysis, graphical verification for residuals, and test statistics for influential points.
In this paper, we proposed a new family of distributions namely exponentiated exponential–geometr... more In this paper, we proposed a new family of distributions namely exponentiated exponential–geometric (E2G) distribution. The E2G distribution is a straightforwardly generalization of the exponential–geometric (EG) distribution proposed by Adamidis and Loukas [A lifetime distribution with decreasing failure rate, Statist. Probab. Lett. 39 (1998), pp. 35–42], which accommodates increasing, decreasing and unimodal hazard functions. It arises on a latent competing
We proposed a new family of lifetime distributions, namely, complementary exponentiated exponenti... more We proposed a new family of lifetime distributions, namely, complementary exponentiated exponential geometric distribution. This new family arises on a latent competing risk scenario, where the lifetime associated with a particular risk is not observable but only the maximum lifetime value among all risks. The properties of the proposed distribution are discussed, including a formal proof of its probability density function and explicit algebraic formulas for its survival and hazard functions, moments,rth moment of theith order statistic, mean residual lifetime, and modal value. Inference is implemented via a straightforwardly maximum likelihood procedure. The practical importance of the new distribution was demonstrated in three applications where our distribution outperforms several former lifetime distributions, such as the exponential, the exponential-geometric, the Weibull, the modified Weibull, and the generalized exponential-Poisson distribution.
The modification of natural areas to meet the needs of human beings is called urbanization. Its e... more The modification of natural areas to meet the needs of human beings is called urbanization. Its effects on bird groups have been extensively studied, and mainly address changes in relative abundance and demographic aspects. Here we wished to determine the probabilities of detection and occupancy of the Great Kiskadee Pitangus sulphuratus in urban environments. We selected 10 sites within the urban area of the city of Santa Helena, western Parana state, southern Brazil, to conduct 5-minute point counts and used occupancy modelling and logistic regression to determine the aforementioned parameters. The probability of detecting the species is suggested to halve as a function of time, while its occupancy probability alone was not related to the levels of afforestation or noise pollution; the number of houses around point counts showed a positive influence on their detection. When we analyzed the probability with the variables together and their interactions, our results suggest that G...
We measured bird diversity over an 800 m range in altitude to test the factors that influence cha... more We measured bird diversity over an 800 m range in altitude to test the factors that influence changes in diversity, in the Atlantic Forest in the state of Sao Paulo, Brazil. We counted forest birds in nine 100 m transects comprising three-point counts, the center of each separated by 200 m. A total of 108 species were found, and diversity was distributed among sampling points and altitude formed a trough-shaped relationship of number of species by area, altitude, and, most strongly, slope. In Principal Coordinate Analysis we found that grouping points by similarity formed three distinct units that were united by altitude: the lowest at near sea level, 100–400 m, and 500–800 m. Thus, we demonstrate that, in the Atlantic Forest, turnover of species with altitude occurs, but unlike higher, often steeper, tropical gradients in Andean forests, where vegetation more clearly changes with elevation, species turnover is more likely to be associated with variables other than changes in vegetation, and which are often not included in studies of the elevation gradient in species richness. The mid-domain effect did not explain altitudinal gradient in diversity, while a quadratic relationship with altitude did, suggesting that reduced abundance and diversity are associated with steeper slopes.
Resumo A ocorrência de falhas em leituras de variáveis meteorológicas em estações de superfície p... more Resumo A ocorrência de falhas em leituras de variáveis meteorológicas em estações de superfície pode comprometer a consistência das séries históricas, inviabilizando ou prejudicando sua utilização. Neste sentido, o objetivo deste trabalho foi avaliar o desempenho de métodos para preenchimento de falhas em séries históricas de dados de evapotranspiração de referência (ETo), considerando a região oeste do Paraná. Foram utilizadas duas estações como referência, estação teste 1 (Foz do Iguaçu) e estação teste 2 (Marechal Cândido Rondon). Foram avaliadas cinco alternativas para preenchimento de falhas: Ponderação Regional com quatro estações vizinhas (PR-4), Ponderação Regional com uma estação vizinha (PR-1), Inverso do Quadrado da Distância (IQD), Mínimos Quadrados (MQ) e dados provenientes do NASA/POWER (NP). Os métodos foram comparados estatisticamente por meio da correlação de Pearson (r), concordância de Willmott (d), coeficiente de eficiência Nash-Sutcliffe (CE), Raiz Quadrada do E...
Production and use of high quality seeds are essential for the soybean crop. Thus, the quality co... more Production and use of high quality seeds are essential for the soybean crop. Thus, the quality control system in seeds industry must be reliable, precise, and fast. Tetrazolium test evaluates not only seeds viability but also their vigor, as well as provides information concerning agents that cause their quality reduction. Although this test does not use expensive devices and reagents, it requires a well-trained analyst. Its precision depends on knowledge of all techniques and required procedures. Besides, also necessary is the observer’s subjectivity. So, this trial aimed at developing a computational tool that could minimize the implicit subjectivity in carrying out this test. It also contributes to generate a greater credibility of information and to guarantee precise answers. Algorithms of supervised classification were applied based on extraction of digital images characterization of tetrazolium test. This procedure aimed at producing pixel-based segmentation of those images, t...
In this paper, we proposed a new family of distributions namely exponentiated exponential–geometr... more In this paper, we proposed a new family of distributions namely exponentiated exponential–geometric (E2G) distribution. The E2G distribution is a straightforwardly generalization of the exponential–geometric (EG) distribution proposed by Adamidis and Loukas [A lifetime distribution with decreasing failure rate, Statist. Probab. Lett. 39 (1998), pp. 35–42], which accommodates increasing, decreasing and unimodal hazard functions. It arises on a latent competing risk scenarios, where the lifetime associated with a particular risk is not observable but only the minimum lifetime value among all risks. The properties of the proposed distribution are discussed, including a formal proof of its probability density function and explicit algebraic formulas for its survival and hazard functions, moments, rth moment of the ith order statistic, mean residual lifetime and modal value. Maximum-likelihood inference is implemented straightforwardly. From a mis-specification simulation study performed in order to assess the extent of the mis-specification errors when testing the EG distribution against the E2G, and we observed that it is usually possible to discriminate between both distributions even for moderate samples with presence of censoring. The practical importance of the new distribution was demonstrated in three applications where we compare the E2G distribution with several lifetime distributions.
ABSTRACT In survival analysis applications, the presence of failure rate functions with non monot... more ABSTRACT In survival analysis applications, the presence of failure rate functions with non monotone shapes is common. Therefore, models that can accommodate such different shapes are needed. In this article, we present a location regression model based on the complementary exponentiated exponential geometric distribution as an alternative to the usual bathtub, increasing, and decreasing failure rates in lifetime data. Assuming censored data, we consider the maximum likelihood inference for analysis, graphical verification for residuals, and test statistics for influential points.
In this paper, we proposed a new family of distributions namely exponentiated exponential–geometr... more In this paper, we proposed a new family of distributions namely exponentiated exponential–geometric (E2G) distribution. The E2G distribution is a straightforwardly generalization of the exponential–geometric (EG) distribution proposed by Adamidis and Loukas [A lifetime distribution with decreasing failure rate, Statist. Probab. Lett. 39 (1998), pp. 35–42], which accommodates increasing, decreasing and unimodal hazard functions. It arises on a latent competing
We proposed a new family of lifetime distributions, namely, complementary exponentiated exponenti... more We proposed a new family of lifetime distributions, namely, complementary exponentiated exponential geometric distribution. This new family arises on a latent competing risk scenario, where the lifetime associated with a particular risk is not observable but only the maximum lifetime value among all risks. The properties of the proposed distribution are discussed, including a formal proof of its probability density function and explicit algebraic formulas for its survival and hazard functions, moments,rth moment of theith order statistic, mean residual lifetime, and modal value. Inference is implemented via a straightforwardly maximum likelihood procedure. The practical importance of the new distribution was demonstrated in three applications where our distribution outperforms several former lifetime distributions, such as the exponential, the exponential-geometric, the Weibull, the modified Weibull, and the generalized exponential-Poisson distribution.
The modification of natural areas to meet the needs of human beings is called urbanization. Its e... more The modification of natural areas to meet the needs of human beings is called urbanization. Its effects on bird groups have been extensively studied, and mainly address changes in relative abundance and demographic aspects. Here we wished to determine the probabilities of detection and occupancy of the Great Kiskadee Pitangus sulphuratus in urban environments. We selected 10 sites within the urban area of the city of Santa Helena, western Parana state, southern Brazil, to conduct 5-minute point counts and used occupancy modelling and logistic regression to determine the aforementioned parameters. The probability of detecting the species is suggested to halve as a function of time, while its occupancy probability alone was not related to the levels of afforestation or noise pollution; the number of houses around point counts showed a positive influence on their detection. When we analyzed the probability with the variables together and their interactions, our results suggest that G...
We measured bird diversity over an 800 m range in altitude to test the factors that influence cha... more We measured bird diversity over an 800 m range in altitude to test the factors that influence changes in diversity, in the Atlantic Forest in the state of Sao Paulo, Brazil. We counted forest birds in nine 100 m transects comprising three-point counts, the center of each separated by 200 m. A total of 108 species were found, and diversity was distributed among sampling points and altitude formed a trough-shaped relationship of number of species by area, altitude, and, most strongly, slope. In Principal Coordinate Analysis we found that grouping points by similarity formed three distinct units that were united by altitude: the lowest at near sea level, 100–400 m, and 500–800 m. Thus, we demonstrate that, in the Atlantic Forest, turnover of species with altitude occurs, but unlike higher, often steeper, tropical gradients in Andean forests, where vegetation more clearly changes with elevation, species turnover is more likely to be associated with variables other than changes in vegetation, and which are often not included in studies of the elevation gradient in species richness. The mid-domain effect did not explain altitudinal gradient in diversity, while a quadratic relationship with altitude did, suggesting that reduced abundance and diversity are associated with steeper slopes.
Resumo A ocorrência de falhas em leituras de variáveis meteorológicas em estações de superfície p... more Resumo A ocorrência de falhas em leituras de variáveis meteorológicas em estações de superfície pode comprometer a consistência das séries históricas, inviabilizando ou prejudicando sua utilização. Neste sentido, o objetivo deste trabalho foi avaliar o desempenho de métodos para preenchimento de falhas em séries históricas de dados de evapotranspiração de referência (ETo), considerando a região oeste do Paraná. Foram utilizadas duas estações como referência, estação teste 1 (Foz do Iguaçu) e estação teste 2 (Marechal Cândido Rondon). Foram avaliadas cinco alternativas para preenchimento de falhas: Ponderação Regional com quatro estações vizinhas (PR-4), Ponderação Regional com uma estação vizinha (PR-1), Inverso do Quadrado da Distância (IQD), Mínimos Quadrados (MQ) e dados provenientes do NASA/POWER (NP). Os métodos foram comparados estatisticamente por meio da correlação de Pearson (r), concordância de Willmott (d), coeficiente de eficiência Nash-Sutcliffe (CE), Raiz Quadrada do E...
Production and use of high quality seeds are essential for the soybean crop. Thus, the quality co... more Production and use of high quality seeds are essential for the soybean crop. Thus, the quality control system in seeds industry must be reliable, precise, and fast. Tetrazolium test evaluates not only seeds viability but also their vigor, as well as provides information concerning agents that cause their quality reduction. Although this test does not use expensive devices and reagents, it requires a well-trained analyst. Its precision depends on knowledge of all techniques and required procedures. Besides, also necessary is the observer’s subjectivity. So, this trial aimed at developing a computational tool that could minimize the implicit subjectivity in carrying out this test. It also contributes to generate a greater credibility of information and to guarantee precise answers. Algorithms of supervised classification were applied based on extraction of digital images characterization of tetrazolium test. This procedure aimed at producing pixel-based segmentation of those images, t...
In this paper, we proposed a new family of distributions namely exponentiated exponential–geometr... more In this paper, we proposed a new family of distributions namely exponentiated exponential–geometric (E2G) distribution. The E2G distribution is a straightforwardly generalization of the exponential–geometric (EG) distribution proposed by Adamidis and Loukas [A lifetime distribution with decreasing failure rate, Statist. Probab. Lett. 39 (1998), pp. 35–42], which accommodates increasing, decreasing and unimodal hazard functions. It arises on a latent competing risk scenarios, where the lifetime associated with a particular risk is not observable but only the minimum lifetime value among all risks. The properties of the proposed distribution are discussed, including a formal proof of its probability density function and explicit algebraic formulas for its survival and hazard functions, moments, rth moment of the ith order statistic, mean residual lifetime and modal value. Maximum-likelihood inference is implemented straightforwardly. From a mis-specification simulation study performed in order to assess the extent of the mis-specification errors when testing the EG distribution against the E2G, and we observed that it is usually possible to discriminate between both distributions even for moderate samples with presence of censoring. The practical importance of the new distribution was demonstrated in three applications where we compare the E2G distribution with several lifetime distributions.
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