189 research outputs found
Comparison on the Bayesian Estimation of Gompertz Distribution Based on Type I Censored Data
The paper depicts assessment of the Bayesian methodology utilizing Gaussian quadrature formulas and Markov Chain Monte Carlo of the Gompertz distribution based on type I censored data with two loss functions, the Square Error loss function and the Linear Exponential loss function. In Markov Chain Monte Carlo, the full conditional distributions for the scale and shape parameters, survival and hazard functions are acquired by means Gibbs sampling and Metropolis- Hastings algorithm. The strategies for the Bayesian methodology are contrasted with maximum likelihood estimation regarding the Mean Square Error (MSE) to decide the best assessing of the scale and shape parameters, survival and hazard functions of the Gompertz distribution based on type I censored data. Keywords: Gompertz distribution, Bayesian estimation, Type I censored data, Gaussian Quadrature Formulas, Markov Chain Monte Carlo
Survival and Hazard Estimation of Weibull Distribution Based on Interval Censored Data
This paper describes the Maximum Likelihood Estimator and the Bayesian using gamma prior Estimator of the Weibull distribution based on interval censored data. The Bayesian estimates of the survival and hazard functions we can’t solve it analytical for that Gauss Quadrature method is used to estimate the survival and hazard functions. Also Lindley’s approximation is used. The two methods are compared to maximum likelihood counterparts and the comparisons are made with respect to the Mean Square Error (MSE) and absolute bias to determine the best for estimating of the survival and hazard function. Keywords: Weibull distribution, survival and hazard functions, Bayesian method, interval censored data, Gauss Quadrature, Lindley’s approximation
Striking enhancement at the site of radiation for nivolumab-induced Stevens-Johnson syndrome
Stevens-Johnson syndrome is a rare adverse cutaneous drug reaction characterized by epidermal detachment of <10% body surface area with an average mortality rate of 1-5%. The mechanism of SJS is not fully understood. Nivolumab is a monoclonal antibody directed against programmed cell death-1 protein (PD-1), a receptor with immune checkpoint inhibitory and antineoplastic activities. We present a case of SJS in a patient being treated with anti-PD-1 therapy nivolumab for metastatic squamous cell carcinoma of the oropharynx. This case is unusual because of the severe accentuation with striking enhancement at his prior radiation site and in the cutaneous region with heavier tumor burden from his metastatic disease. This reaction may give insight to the underlying pathophysiology of SJS, suggesting that immune checkpoint inhibitors can activate T-cells to target keratinocytes and that external factors may be involved in creating distinct epitopes for T-cell recognition. We hope this case adds to the body of knowledge in the pathogenesis of Stevens-Johnson syndrome and cutaneous adverse events seen with checkpoint inhibitors
Bayesian survival estimator for Weibull distribution with censored data.
As the most useful distribution for modeling and analyzing life time data in the medical, paramedical and applied sciences among others, Weibull distribution stands out. Nowadays great attention has been given to Bayesian approach and is in contention with other estimation methods. This study explores and compares the performance of Maximum Likelihood and Bayesian using Jeffrey prior and the extension of Jeffrey prior information for estimating the survival function of Weibull distribution with right censored data. On the performance of these estimators with respect to the mean square error and mean percentage error, comparisons are made through simulation study. For all the varying sample size, several specific values of the scale parameter of the Weibull distribution and for the values given for the extension of Jeffrey prior, the estimate of survival function of maximum likelihood is the best compared to the others when the value of extension of Jeffrey prior is 0.4. But then, extension of Jeffrey prior result is the best compared to others when the value of extension of Jeffrey is 1.4. © 2011 Asian Network for Scientific Information
FINITE ELEMENT MODELING OF RING SPLITTING TEST TO PREDICT RESIDUAL STRESSES IN SPIRAL WELDED PIPE
FINITE ELEMENT MODELING OF RING SPLITTING TEST TO PREDICT RESIDUAL STRESSES IN SPIRAL WELDED PIPE
Comparison of the Bayesian and maximum likelilhood estimation for Weibull distribution
Problem statement: The Weibull distribution has been widely used especially in the modeling of lifetime event data. It provides a statistical model which has a wide variety of applications in many areas, and the main advantage is its ability in the context of lifetime event, to provide
reasonably accurate failure analysis and failure for
ecasts especially with extremely small samples. The
conventional maximum likelihood method is the usual way to estimate the parameters of a distribution. Bayesian approach has received much attention and in contention with other estimation methods. In this study we explore and compare the performance of the maximum likelihood estimate with the Bayesian estimate for the Weibull distribution.
Approach: The maximum likelihood estimation, Bayesian using Jeffrey prior and the extension of Jeffrey prior information for estimating the parameters of Weibull distribution of life time are presented. We explore the performance of these estimators numerically under varyin
g conditions. Through the simulation study comparison are made on the performance of these estimators with respect to the Mean Square Error (MSE) and Mean Percentage Error(MPE).
Results: For all the varying sample size, several specific values of the scale parameter of the Weibull distribution and for the values specify for the extension of Jeffrey prior, the estimators of the maximum likelihood method result in smaller MSE and MPE compared to Bayesian
in majority of the cases. Nevertheless in all cases for both methods the MSE and MPE decrease as sample size increases.
Conclusion: Based on the results of this simulation study the Bayesian approach used in the estimating of Weibull parameters is found to be not superior compared to the
conventional maximum likelihood method with respect to MSE and MPE values
Patients’ and Nurses’ Perceptions of Post-Coronary Artery Bypass Graft Learning Needs in Two Omani Hospitals
ABSTRACT: Objectives: Little is known about nurses’ and patients’ perceptions of learning needs following coronary artery bypass graft (CABG) surgery in Oman. This study aimed to identify patients' and nurses' perceptions of post-CABG learning needs. Methods: This cross-sectional study was conducted in two cardiac units in Oman between February and April 2018. Participants were from step-down units and perceptions of post-CABG learning needs were collected using a modified version of the Cardiac Patients Learning Need Inventory (MCPLNI) questionnaire. Data were analysed using descriptive and inferential statistics. Results: A total of 90 patients and 90 nurses were included in this study (response rate: 100%). Nurses perceived information about chest and leg wound care, medications and complications as patients’ most important learning needs (4.89 ± 0.31, 4.84 ± 0.33 and 4.78 ± 0.45, respectively). Similarly, patients perceived a need for post-CABG learning related to chest and leg wound care, complications and medication, while learning related to physical activity received a moderate priority (4.92 ± 0.20, 4.80 ± 0.45, 4.85 ± 0.26 and 3.50 ± 1.34, respectively). Conclusion: Before discharging patients, they should be provided with specific information related to post-CABG care. It is essential to assess patients’ learning needs and incorporate those learning needs into discharge plans.Keywords: Learning; Perception; Coronary Artery Bypass; Education; Patients; Nurses; Oman
Corporate Governance Mechanism and Narrowing Expectations Gap: Evidence of Jordan
This study aimed to examine the impact of applying corporate governance mechanism to narrowing expectations gap in auditing. This study was performed through distributing questionnaire, which was developed to provide the necessary data for the research questions. The results of the study indicated that there is a relation between governance and expectation gap. Furthermore, the study recommended implementing the mechanics of governance to activate good practices of corporate governance, develop necessary sanctions for violating the auditor to professional standards, especially accounting standards, independence standard and professional competence standards. Keywords: Corporate Governance, expectation Gap, auditor's responsibility, effective of internal control
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