.This article proposes some new estimators, namely Stein’s estimators for ridge regression and Kibria and Lukman estimator and compares their performance with some existing estimators, namely maximum likelihood estim...
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.This article proposes some new estimators, namely Stein’s estimators for ridge regression and Kibria and Lukman estimator and compares their performance with some existing estimators, namely maximum likelihood estimator (MLE), ridge regression estimator, Liu estimator, almost unbiased ridge and Liu estimators, adjusted Liu estimator, James stein’s estimator, Kibria and Lukman estimator, Dorugade estimator, and modified ridge estimator for the logistic regression model to solve the multicollinearity problem. The bias, covariance matrix, and mean square error matrix for each of the estimators are provided. A Monte Carlo simulation has been conducted to compare the performance of different estimators. We consider the smaller mean squared error value as a performance criterion. From the simulation study, it is evident that all proposed estimators performed better than the MLE. Finally, a real-life data is analyzed to illustrate the findings of the article. Some promising estimators are recommended for the practitioners.
Chromosomal fragile sites (CFSs) are loci or regions susceptible to spontaneous or induced occurrence of breaks and rearrangements. They are classified in two main categories, rare and common, depending on their frequ...
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Chromosomal fragile sites (CFSs) are loci or regions susceptible to spontaneous or induced occurrence of breaks and rearrangements. They are classified in two main categories, rare and common, depending on their frequency in the population. In order to identify which CFSs are influential or significant in the occurrence of deletions and duplications (chromosomal constitutional imbalances), we propose a logisticregression analysis for the CFS data set, since the underlying response variable is categorical, specifically binary (deletion or duplication). Some results are presented here as an informative preliminary contribution to understand the frailty of these CFS in increasing/decreasing of the deletion odds. This study has implications for our comprehension of human pathogenesis.
Liver necroinflammation is the indicator for treating patients with chronic hepatitis B (CHB) infection. However, there is no suitable non-invasive index for diagnosing liver necroinflammation. This study aimed to cre...
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Liver necroinflammation is the indicator for treating patients with chronic hepatitis B (CHB) infection. However, there is no suitable non-invasive index for diagnosing liver necroinflammation. This study aimed to create a non-invasive index to predict liver necroinflammation in patients who lack clear-cut clinical inflammation parameters. Patients who were hepatitis B e antigen (HBeAg)-negative and underwent liver histological diagnosis, had a normal or minimally increased alanine aminotransferase (ALT) level were enrolled. Liver necroinflammation was defined as histological active index >= 4. A logistic regression model (LRM) was established based on the parameters independently associated with liver necroinflammation. Of all 550 patients, 36.73% had necroinflammation. In patients with an abnormal ALT level, the rate of necroinflammation was 52.49%. The area under the curve (AUC) of the ALT level for predicting necroinflammation was 0.655 (95% confidence interval [CI], 0.609-0.702), and that of the HBV DNA level >= 2000 IU/mL combined with an abnormal ALT level was 0.618. By using the LRM, the AUC improved to 0.769 (95% CI, 0.723-0.815) with a Youden index of 0.519 and diagnostic accuracy of 75.3%. The cutoff value >= 0.7 in the LRM had a specificity of 97.4% and positive predictive value of 85.0% for predicting necroinflammation. By using the cutoff value <0.15 in the LRM, the presence of necroinflammation could be excluded with a negative predictive value of 90.8%. This study indicated that the LRM can be used to effectively diagnose liver necroinflammation in HBeAg-negative patients with CHB who have normal or minimally elevated ALT levels.
A food texture evaluation method using a magnetic food texture sensor is proposed for the visualization of food texture. The food texture sensor measures two time-series waves, one of force and one of vibration, durin...
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A food texture evaluation method using a magnetic food texture sensor is proposed for the visualization of food texture. The food texture sensor measures two time-series waves, one of force and one of vibration, during fracture of a food sample. Twenty profiles were extracted from the two waves. The evaluation method selected the profiles to use in the logisticmodel and determined the coefficients of the model based on the results of sensory tests. Laboratory experiments confirmed that the logisticmodel evaluated the food textures as radar charts. In addition, the model can potentially evaluate the food textures of unknown foods. (C) 2017 Elsevier Ltd. All rights reserved.
It is well known that pigs are sensitive to heat stress, but few studies have assessed the critical temperature that affects farrowing rate. Therefore, the objective of the present study was to assess the effects of o...
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It is well known that pigs are sensitive to heat stress, but few studies have assessed the critical temperature that affects farrowing rate. Therefore, the objective of the present study was to assess the effects of outside temperature on farrowing rate by using a multivariate logistic regression model. Data were obtained from 25 commercial farms, including 26,128 service records for gilts and 120,655 service records for sows. Two variables, maximum temperature (MAX) and temperature humidity index (THI), were used as an indicator for climate conditions. In gilts, an interaction between climate conditions and service number was associated with farrowing rate (p<.05). In the first service, farrowing rate decreased as climate conditions increased, whereas no relationship was found in the second service or later. In sows, farrowing rate at first service decreased as MAX increased from 22 degrees C or THI increased from 66 (p<.05), but no apparent reduction under heat conditions was found in the second service or later. Additionally, effect of heat stress on farrowing rate in parities 1-2 was higher than those in parities 3-5 and 6 (p<.05). These results can be applied to field conditions as a standard for the critical temperature for farrowing rate.
The main objective of this study is to evaluate the performances of different earthquake-induced landslides susceptibility mapping models at mountainous regions in China. At first, 160 earthquake-induced landslide poi...
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The main objective of this study is to evaluate the performances of different earthquake-induced landslides susceptibility mapping models at mountainous regions in China. At first, 160 earthquake-induced landslide points were identified from field investigations. Concurrently, based on the results of a literature review and the field investigation, 12 influencing factors were considered, and the corresponding thematic layers were generated using geographic information system (GIS) technology. Subsequently, 20 groups with a fixed number of cells were collected as a common training dataset for the two different models, based on a random selection from the entire database (including landslide cells and no-landslide cells). The neural network (NN) model and logisticregression (LR) model were developed with R software. Finally, earthquake-induced landslides susceptibility maps of Wenchuan county were produced, very low, low, medium, high and very high susceptibility zones cover. The validation results indicate that the landslide data from field investigations are in good agreement with the evaluation results, and the LR model has a slightly better prediction than the NN model in this case. In general, the NN model and LR models are satisfactory for susceptibility mapping of earthquake-induced landslides at mountainous regions.
This article considers some different parameter estimation methods in logistic regression model. In order to overcome multicollinearity, the almost unbiased ridge-type principal component estimator is proposed. The sc...
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This article considers some different parameter estimation methods in logistic regression model. In order to overcome multicollinearity, the almost unbiased ridge-type principal component estimator is proposed. The scalar mean squared error of the proposed estimator is derived and its properties are investigated. Finally, a numerical example and a simulation study are presented to show the performance of the proposed estimator.
The size of the network traffic is of great significance to the design of the network architecture. This paper forecast network traffic based on logistic regression model, proposes an improved network traffic forecast...
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ISBN:
(数字)9781728188232
ISBN:
(纸本)9781728188232
The size of the network traffic is of great significance to the design of the network architecture. This paper forecast network traffic based on logistic regression model, proposes an improved network traffic forecasting method. In this method, the logistic regression model parameters need to be estimated from historical data. For the three unknown parameters in the logistic regression model, first use the Neyman-Fisher factorization theorem to obtain the unbiased sufficient statistics of one of the parameters. Under the assumption that the general solution is known, use the least square method to solve the other two parameters. Then, under the premise of satisfying the constraints, the scope of the general solution is determined. Among all the parameters, the parameter with the smallest model error is selected to obtain the logisticregression prediction model. Experimental simulations prove that the method improves the accuracy of network traffic forecasting.
Since the patients who suffer from tuberculosis when referring to the physician, they are without any specific symptoms of isolation and treatment and prevention of transmission of the disease to other people. This st...
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Since the patients who suffer from tuberculosis when referring to the physician, they are without any specific symptoms of isolation and treatment and prevention of transmission of the disease to other people. This study aimed to determine the variables affecting tuberculosis using the logisticregression prediction model. This cross-sectional study enrolled 378 people (189 TB patients as a patients group and 189 healthy individuals as a control group) from Ghaem and Imam Reza hospitals, Mashhad (Iran) during March 2011 to December 2014. The variables affecting TB patients such as age, sex, and marital status, AIDS, smoking, history of asthma, organ transplantation, body mass index (BMI), vitamin D3 level, Diabetes, hemoglobin, and malignant diseases were compared in two groups. The sensitivity, specificity, ROC curve (Receiver operating characteristic) and positive and negative predictive values were used to evaluate the predictive power of logistic regression model. Data analyzed using SPSS software version 22 through logistic regression model and Chi-square test. And P-value < 0.05 were considered statistically significant. The sensitivity and specificity of this model in predict the tuberculosis were 78% and 68%, respectively. Also, the area under the curve (Roc) was 0.821. Variables;vitamin D3 (p = 0.01), hemoglobin (p = 0.01) and body mass index (BMI) (p = 0.01) significantly associated with tuberculosis. The results showed that the variables of vitamin D3, hemoglobin and body mass index (BMI) have a better prediction of TB in the logistic regression model.
logisticregression is often confronted with separation of likelihood problem, especially with unbalanced success-failure distribution. We propose to address this issue by drawing a ranked set sample (RSS). Simulation...
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logisticregression is often confronted with separation of likelihood problem, especially with unbalanced success-failure distribution. We propose to address this issue by drawing a ranked set sample (RSS). Simulation studies illustrated the advantages of logistic regression models fitted with RSS samples with small sample size regardless of the distribution of the binary response. As sample size increases, RSS eventually becomes comparable to SRS, but still has the advantage over SRS in mitigating the problem of separation of likelihood. Even in the presence of ranking errors, models from RSS samples yield higher predictive ability than its SRS counterpart.
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