Consulta: subjectFacets:"Regression models"
Registros recuperados: 17
Data/hora: 09/06/2024 04:01:42

APPARENT DENSITY AS AN ESTIMATOR OF WOOD PROPERTIES OBTAINED IN TESTS WHERE FAILURE IS FRAGILE
Provedor de dados: 70
Autores: Christoforo,André L.; Couto,Natalia G.; Almeida,João P. B.; Aquino,Vinicius B. de M.; Lahr,Francisco A. R.
ABSTRACT The use of new wood species in construction requires knowledge of their properties for safer and more economical structural sizing. In Brazil, structural projects are carried out according to the standard document ABNT NBR 7190:1997. Tests required by this standard for the complete characterization of species require large machines with high costs, which are present only in large research centers. Considering the lack of experimental determination, this study aimed, with the help of analysis of variance of regression models, to investigate the possibility of estimating, through apparent density, wood properties obtained in tests where failure is considered fragile, allowing the estimation of properties of species still little used. Ten wood...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hardwoods; Fragile failure; Regression models; Analysis of variance.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000100105

PHYSICO-MECHANICAL CHARACTERIZATION OF THE Anadenanthera colubrine WOOD SPECIE
Provedor de dados: 70
Autores: Christoforo,André L.; Aftimus,Bruno H. C.; Panzera,Tulio H.; Machado,Gilmara de O.; Lahr,Francisco A. R.
ABSTRACT In Brazil, the characterization of wood is carried out in accordance with the premises established by ABNT NBR 7190standard; however, the determination of wood properties requires the use of equipment, which hinders the wood characterization for the construction professional. To circumvent this problem, the properties of wood strength and stiffness can be estimated through regression models using the apparent density as estimator, being the density a physical property of easy determination. This study aimed to determine 4 physical and 13 mechanical properties of “Angico Branco” wood (Anadenanthera colubrina), and with the aid of regression models based on analysis of variance, estimate the strength and stiffness properties as a function of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Anadenanthera colubrina; Physico-mechanical characterization; Apparent density; Regression models; Analysis of variance (ANOVA).
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162017000200376

EVALUATION OF THE Peltophorum vogelianum Benth. WOOD SPECIES FOR STRUCTURAL USE
Provedor de dados: 70
Autores: Christoforo,André L.; Aquino,Vinicius B. de M.; Wolenski,Anderson R. V.; Araujo,Victor A. De; Lahr,Francisco A. R.
ABSTRACT Wood is a material used for various purposes since ancient times and is mainly used in civil and rural construction and industry. Due to the predatory exploitation of known trees, it is necessary to characterize new species for use in urban and rural structures as alternatives of species commonly used. This study aimed to determine the physical and mechanical properties of Guarucaia wood (Peltophorum vogelianum Benth.) based on the Brazilian standard ABNT NBR 7190 (1997) and estimate the strength and stiffness as a function of apparent density using the analysis of variance and also estimate stiffness as a function of its strength. The mechanical properties of P. vogelianum were considered compatible for structural use when compared with others...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Peltophorum vogelianum; Characterization; Apparent density; Regression models; Analysis of variance (ANOVA).
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000600763

INFLUENCE OF FATIGUE ON BENDING OF Pinus caribaea WOOD
Provedor de dados: 70
Autores: Christoforo,André L.; Barbosa,Thaina Q.; Almeida,Diego H. de; Panzera,Tulio H.; Lahr,Francisco A. R.
ABSTRACT This research aimed to evaluate the effect of the number of fatigue cycles (NC, 0 – reference, 450, 4500, 45000, and 90000) for frequencies (Fr) of oscillation equal to 0.5 and 1.0 Hz on the modulus of elasticity (Em) and operating stress (σm) in the static bending of Pinus caribaea wood. Em and σm were determined taking into account three specimens (SPEC) manufactured for reference condition and another three for each of the four NC levels and each Fr level, resulting in 27 SPEC. Sixty experimental determinations were obtained, being the approximate total time of sample exposure to fatigue of 350 hours. The same specimens used to determine Em and σm for the reference condition were also used (via non-destructive tests) to obtain these properties...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fatigue; Pinus caribaea; Static bending; Analysis of variance; Regression models.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000200238

Evaluation of Three Mathematical Functions to Describe the Relationship Between Body Weight, Body Condition and Testicular Dimensions in Yankasa Sheep
Provedor de dados: 77
Autores: Yakubu,A; Musa-Azara,I. S.
Body size and testicular measurements have been found to be important parameters utilized in breeding soundness evaluation. The present study therefore, aimed at determining the relationship between body weight (BW), body condition score (BCS), testicular length (TL), testicular diameter (TD) and scrotal circumference (SC) in 120 extensively reared Yankasa rams (approximately 30 months old) using linear, quadratic and cubic predictive models. Coefficient of determination (R2), Adjusted R2, the estimate of Mallows' Cp, RMSE (Root mean squares error) and the parsimony principle (p=number of parameters) were used to compare the efficiency of the different models. Strong Pearson's correlation coefficients (r = 0.83-0.94; P&lt;0.01) were found between BW, TL,...
Tipo: Journal article
Palavras-chave: Body size; Body condition; Testicular measurements; Rams; Regression models.
Ano: 2013
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-95022013000400036

Traditional and generic height-diameter relationship models for Pinus caribaea var. hondurensis
Provedor de dados: 190
Autores: Mendonça, Adriano Ribeiro de; Corandin, Cínthia Mazon; Pacheco, Gustavo Rezende; Vieira, Giovanni Correia; Araújo, Márcio da Silva; Interamnense, Márcio Torreão.
This study aimed to evaluate traditional and generic models to estimate the height-diameter relationship of Pinus caribaea var. hondurensis. The data used were from trees of different ages, sites and planting densities. Total height of the trees were estimate using ten models. The models were evaluate according to the adjusted coefficient of determination, standard error of estimate, relative standard error, bias, mean differences and standard deviation of differences. Beyond these statistics, the models were evaluated by plotting the observed height versus estimated height. There was a greater accuracy of the generic models.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Height-diameter relationship; Regression models; Height Recursos Florestais; Engenharia Florestal; Manejo Florestal; Dendrometria e Inventário Florestal Relação altura-diâmetro; Modelos de regressão; Altura.
Ano: 2014
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/710

Explained variation for survival models
Provedor de dados: 31
Autores: Royston,   Patrick.
This article introduces a new measure of explained variation for use with censored survival data. It is a modified version of a measure previously described by John O’Quigley and colleagues, itself a modification of Nagelkerke’s earlier proposal for a general index of determination. I describe Stata programs str2ph, which implements the new measure, and str2d, which implements a measure proposed in 2004 by Royston and Sauerbrei. I provide examples with real data.
Tipo: Journal Article
Palavras-chave: Censored survival data; Regression models; Index of determination; Explained variation; Explained randomness; Information gain; Research Methods/ Statistical Methods.
Ano: 2006
URL: http://purl.umn.edu/117558

Review of Regression Models for Categorical Dependent Variables Using Stata by Long and Freese
Provedor de dados: 31
Autores: Hendrickx,   John.
This article reviews Regression Models for Categorical Dependent Variables Using Stata by Long and Freese.
Tipo: Journal Article
Palavras-chave: Categorical data; Regression models; Research Methods/ Statistical Methods.
Ano: 2002
URL: http://purl.umn.edu/115954

Does Marginal Price Matter? A Regression Discontinuity Approach to Estimating Water Demand
Provedor de dados: 31
Autores: Nataraj,   Shanthi; Hanemann,   W. Michael.
Although complex pricing schedules are increasingly common in utility billing, it is difficult to determine whether consumers respond to complicated marginal prices because price changes are often confounded with simultaneous demand shocks or non-price policies. To overcome this challenge, we exploit a natural experiment - the introduction of a third price block in an increasing block pricing schedule for water - in Santa Cruz, California. Using a regression discontinuity design, we find that consumers do respond to changes in marginal price. Doubling marginal price led to a 12% decrease in water use (500 cubic feet per bill) among high-use households.
Tipo: Working or Discussion Paper
Palavras-chave: Water demand; Regression models; Price policy; Consumer behavior; Demand and Price Analysis; Research Methods/ Statistical Methods; D12; Q21; Q25; L95.
Ano: 2008
URL: http://purl.umn.edu/47078

Review of Regression Models for Categorical Dependent Variables Using Stata, Second Edition, by Long and Freese
Provedor de dados: 31
Autores: Williams,   Richard A.
This article reviews Regression Models for Categorical Dependent Variables Using Stata, Second Edition, by Long and Freese.
Tipo: Journal Article
Palavras-chave: Categorical data; Regression models; Research Methods/ Statistical Methods.
Ano: 2006
URL: http://purl.umn.edu/117578

Prediction of Topsoil Texture Through Regression Trees and Multiple Linear Regressions
Provedor de dados: 90
Autores: Pinheiro,Helena Saraiva Koenow; Carvalho Junior,Waldir de; Chagas,César da Silva; Anjos,Lúcia Helena Cunha dos; Owens,Phillip Ray.
ABSTRACT: Users of soil survey products are mostly interested in understanding how soil properties vary in space and time. The aim of digital soil mapping (DSM) is to represent the spatial variability of soil properties quantitatively to support decision-making. The goal of this study is to evaluate DSM techniques (Regression Trees - RT and Multiple Linear Regressions - MLR) and the ability of these tools to predict mineral fraction content under a wide variability of landscapes. The study site was the entire Guapi-Macacu watershed (1,250.78 km2) in the state of Rio de Janeiro in the Southeast region of Brazil. Terrain attributes and remote sensing data (with 30 m of spatial resolution) were used to represent landscape co-variables selected as an input in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Terrain attributes; Soil depth functions; Digital soil mapping; Regression models.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100304

Pedotransfer functions related to spatial variability of water retention attributes for lowland soils
Provedor de dados: 90
Autores: Nebel,Álvaro Luiz Carvalho; Timm,Luís Carlos; Cornelis,Wim; Gabriels,Donald; Reichardt,Klaus; Aquino,Leandro Sanzi; Pauletto,Eloy Antonio; Reinert,Dalvan José.
The estimation of non available soil variables through the knowledge of other related measured variables can be achieved through pedotransfer functions (PTF) mainly saving time and reducing cost. Great differences among soils, however, can yield non desirable results when applying this method. This study discusses the application of developed PTFs by several authors using a variety of soils of different characteristics, to evaluate soil water contents of two Brazilian lowland soils. Comparisons are made between PTF evaluated data and field measured data, using statistical and geostatistical tools, like mean error, root mean square error, semivariogram, cross-validation, and regression coefficient. The eight tested PTFs to evaluate gravimetric soil water...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Soil water content; Planosol; Gleisol; Hydraulic properties; Geostatistics; Regression models.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000300008

Prediction of weight and percentage of salable meat from Brazilian market lambs by subjective conformation and fatness scores
Provedor de dados: 96
Autores: Ricardo,Hélio de Almeida; Roça,Roberto de Oliveira; Lambe,Nicola Ross; Seno,Leonardo de Oliveira; Fuzikawa,Ingrid Harumi de Souza; Fernandes,Alexandre Rodrigo Mendes.
ABSTRACT This study assessed the use of conformation and fatness scores of the EUROP sheep carcass grading system to predict weight and percentage of salable meat from Brazilian market lambs. Data were collected from in vivo, carcass, and retail production from 252 uncastrated lambs. Evaluated models included single regressions, two multivariate models, and one determined by the stepwise procedure. Conformation was moderately correlated with weight of salable meat. Fatness scores were correlated with rump perimeter, carcass width, and thoracic depth with coefficients of −0.33, −0.32, and −0.23, respectively. Body weight was the best single predictor for weight of salable meat and cold carcass yield for percentage of salable meat. All multivariate models...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Regression models; Retail cuts; Sheep.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982016001000639

Metabolisable energy prediction in energy feedstuffs and evaluation of the stepwise validation procedure using bootstrapping
Provedor de dados: 124
Autores: Oliveira,Newton Tavares Escocard de; Pozza,Paulo Cesar; Castilha,Leandro Dalcin; Pasquetti,Tiago Junior; Langer,Carolina Natali.
ABSTRACT The use of predicted values of apparent metabolisable energy (AME), obtained from regression equations, can be useful for both research institutions and nutrition industries. However, there is a need to validate independent samples to ensure that the predicted equation for AME is reliable. In this study, data was collected in order to estimate the prediction equations of corn, sorghum and wheat bran for pig feed, based on the chemical composition, in addition to evaluating the validity of the stepwise selection procedure regressive method of non-parametric bootstrap resampling. Data from metabolism trials in pigs and the chemical composition of feedstuffs was collected from both Brazilian and international literature, expressed as dry matter....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chemical composition; Corn; Meta-analysis; Pigs; Regression models.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902019000100131

Analysis of the adaptability of black bean cultivars by means of quantile regression
Provedor de dados: 65
Autores: Barroso,Laís Mayara Azevedo; Nascimento,Moysés; Barili,Leiri Daiane; Nascimento,Ana Carolina Campana; Vale,Naine Martins do; Silva,Fabyano Fonseca e; Carneiro,José Eustáquio de Souza.
ABSTRACT:  The aim of this study was to use quantile regression (QR) to characterize the effect of the adaptability parameter throughout the distribution of the productivity variable on black bean cultivars launched by different national research institutes (research centers) over the last 50 years. For this purpose, 40 cultivars developed by Brazilian genetic improvement programs between 1959 and 2013 were used. Initially, QR models were adjusted considering three quantiles (τ = 0.2, 0.5 and 0.8). Subsequently, with the confidence intervals, quantile models τ = 0.2 and 0.8 (QR0.2 and QR0.8) showed differences regarding the parameter of adaptability and average productivity. Finally, by grouping the cultivars into one of the two groups defined from QR0.2...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gene-environment (GxE) interaction; Phaseolus vulgaris L; Genetic improvement; Quantiles; Regression models.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000300200

Positioning and number of nutritional levels in dose-response trials to estimate the optimal-level and the adjustment of the models
Provedor de dados: 65
Autores: Souza,Fernando Augusto de; Malheiros,Euclides Braga; Carneiro,Paulo Roberto Oliveira.
The aim of this research was to evaluate the influence of the number and position of nutrient levels used in dose-response trials in the estimation of the optimal-level (OL) and the goodness of fit on the models: quadratic polynomial (QP), exponential (EXP), linear response plateau (LRP) and quadratic response plateau (QRP). It was used data from dose-response trials realized in FCAV-Unesp Jaboticabal considering the homogeneity of variances and normal distribution. The fit of the models were evaluated considered the following statistics: adjusted coefficient of determination (R²adj), coefficient of variation (CV) and the sum of the squares of deviations (SSD).It was verified in QP and EXP models that small changes on the placement and distribution of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Regression models; Chicken nutrition; Dose-response trials; Linear response plateau; Quadratic response plateau.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782014000701204

Influence of diameter measuring height on the adjustment of volume and biomass equations of cerrado in minas gerais
Provedor de dados: 64
Autores: Morais,Vinícius Augusto; Mello,José Márcio de; Gomide,Lucas Rezende; Scolforo,José Roberto Soares; Araújo,Emanuel José Gomes de; Rufini,Ana Luiza.
Different tree diameter measuring heights are displayed in the literature, which in some cases can lead to different results in the final estimates, if the model used is not compatible with the diameter measurement height. The aim of this study was to evaluate and validate equations of volume and biomass, adjusted by Goal Programming and regression by Ordinary Least Squares Method for the Cerrado Sensu Stricto and Campo Cerrado in Minas Gerais state, using information on diameters measured at 0. 10, 0.30 and 1.30 meters from the ground level. Thus, we rigorously scaled 868 trees in areas of Cerrado Sensu Stricto and Campo Cerrado of Minas Gerais. Two different models were subsequently adjusted, one being dual input with the diameter measured at different...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Regression models; Forest inventory Brazilian; Savannas.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542014000300002