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Apr 18, 2024Open    Access

Penalized Spline Estimation for Nonparametric Multiplicative Regression Models

威 陈
In this paper, we consider the estimation problem of the unknown link function in the nonparametric multiplicative regression model. Combining the penalized splines technique, a least product relative error estimation method is proposed, where a effective model degree of freedom is defined, then the smoothing parameter is chosen by some information criterions. Simulation studies show that these strategies work well. Some asymptotic properties are established. A real data set is analyzed to illus...
Open Access Library J.   Vol.11, 2024
Doi:10.4236/oalib.1111352


Jun 27, 2023Open    Access

Analysis of a Two-Stage Negative Binomial Group Testing Model for Estimating the Prevalence of a Rare Trait

Francis Mwangi Kariuki, Ronald Waliaula Wanyonyi, Ali Salim Islam
This paper presents the analysis of a two-stage negative binomial group testing estimator of the prevalence of a rare trait when imperfect diagnostic tests with known sensitivity and specificity were used. The study utilized the method of Maximum Likelihood Estimation (MLE) to obtain the estimator and the Cramer-Rao lower bound method to compute the Fischer information of the estimator. The properties of the constructed estimator are discussed and the efficiency of the constructed estimator rela...
Open Access Library J.   Vol.10, 2023
Doi:10.4236/oalib.1110141


May 27, 2022Open    Access

Correlation and Simultaneous Linear Regression

Khaled Fattah Sheet, Khawla Musta Sadiq
Hirschfled (1935) posed the question. Is it always possible to introduce new variates for the rows and the columns of the contingency-table such that both regressions are linear. In reply, he derived the formulas of dual sealing. This approach was later employed by Lingoes (1963, 1968) who was obviously unaware of Hirschfeld’s study, but noted that the approach would use the basic theory and equation worked out by Guttman (1941). We have to use a graphic with linear regression to find optimal we...
Open Access Library J.   Vol.9, 2022
Doi:10.4236/oalib.1108425


May 27, 2022Open    Access

Improving the Ordinary Least Squares Estimator by Ridge Regression

Ghadban Khalaf
In the presence of multicollinearity, ridge regression techniques result in estimated coefficients that are biased but have smaller variance than Ordinary Least Squares estimators and may, therefore, have a smaller Mean Squares Error (MSE). The ridge solution is to supplement the data by stochastically shrinking the estimates toward zero. In this study, we propose a new estimator to reduce the effect of multicollinearity and improve the estimation. We show by a simulation study that the MSE of t...
Open Access Library J.   Vol.9, 2022
Doi:10.4236/oalib.1108738


Apr 24, 2022Open    Access

Improving GM(1,1) Model Performance Accuracy Based on the Combination of Optimized Initial and Background Values in Time Series Forecasting

Mahdi Madhi, Norizan Mohamed
The term grey forecasting model has been comprehensively utilized in numerous research arenas and discovered valid outcomes. Nevertheless, the model possesses certain possible problems that necessitate improvement. It has been proven that, part of the foremost issues distressing the prediction accurateness of the model are initial and background values. Henceforth, a new modified GM(1,1) model through the combination of optimized initial value and background value has been recommended in this st...
Open Access Library J.   Vol.9, 2022
Doi:10.4236/oalib.1108416


Jan 29, 2022Open    Access

Modeling and Forecast of Ghana’s GDP Using ARIMA-GARCH Model

Dwumah Barbara, Chenlong Li, Yingchuan Jing, Aning Samuel
GDP is frequently used as a way of national evaluations, as well as a way of measuring economic progress. This paper analyses a combination of time series models that are both linear and non-linear in making forecast of Ghana’s GDP. Ghana’s GDP current prices data from 1980 to 2019 were used in the analysis. Based on the AIC values, the best model was determined to be ARIMA (2, 2, 2) in modeling our data, except that it is heteroscedastic. The combination with non-linear GARCH (1, 1) model is us...
Open Access Library J.   Vol.9, 2022
Doi:10.4236/oalib.1108335


Nov 24, 2021Open    Access

Simulation Study on Geometric Anisotropic Estimators for Spatial Point Process

Williams Kumi
The method by Fry for detecting geometric anisotropy in stationary spatial point pattern is investigated. We quantify anisotropy by stretching and compressing the point process about the axis. Using a simulated Strauss point pattern, we first fit ellipsoids to the compressed pattern of pairwise difference vectors to estimate the direction of anisotropy. The strength of compression and the regularity of the point process are varied at different times and the corresponding effect on the estimated ...
Open Access Library J.   Vol.8, 2021
Doi:10.4236/oalib.1108095


Sep 30, 2021Open    Access

A Note on Surface Integrals of Vector Fields

Zhengyuan Wei, Xiaoya Zhou, Jinrong Jiang
Surface integrals of vector fields play an important role in the solutions of natural science and physical science. The Gauss theorem reduces the difficulty of directly computing surface integrals of vector fields. This paper introduces an approach for the computation of integral surfaces in vector fields and obtains a generalized mathematical expression based on Gauss theorem. Moreover, the computation time is investigated by two classical examples.
Open Access Library J.   Vol.8, 2021
Doi:10.4236/oalib.1107934


Oct 19, 2020Open    Access

Polynomial-Based Smoothing Estimation for a Semiparametric Accelerated Failure Time Partial Linear Model

Wei Chen, Fengling Ren
The accelerated failure time partial linear model allows the functional form of the effect of covariates to be possibly nonlinear and unknown. We propose to approximate the nonparametric component by cubic B-splines and construct a Gehan estimating function similar to that under the AFT model. Due to its non-smoothness, which will lead to computational challenge in estimating standard error, we propose a polynomial-based smoothing Gehan estimating function and compute the estimate of the paramet...
Open Access Library J.   Vol.7, 2020
Doi:10.4236/oalib.1106824


Jun 24, 2020Open    Access

Study on Patterns of Human Cancer Using SSN Method

Chaoyu Zhang
Human cancer, which has complex pathogenesis, is generally relative to the dysfunction of biological systems. Thus, our research is not at molecular level, but at system level, i.e. molecular network. In this paper, specially, we use PPI network. In order to construct a PPI network, we used the SSN method which is proposed by Professor X. Liu and others. The SSN method is distinct from the traditional network methods, especially in screening differential expressed genes. Besides, the traditional...
Open Access Library J.   Vol.7, 2020
Doi:10.4236/oalib.1106453


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