Ammar Sarhan

Followers

Following

Co-authors

Public Views

Armando Salvatore

McGill University

Cristiana Facchini

Università di Bologna

Remo Caponi

University of Cologne

Derek Abbott

University of Adelaide

Elliot Wolfson

University of California, Santa Barbara

Daniel Abrams

Bar-Ilan University

Eitan Fishbane

Jewish Theological Seminary of America

Shaul Magid

Harvard University

Steven M. Wasserstrom

Reed College

Adam Teller

Brown University

Interests

Uploads

Papers by Ammar Sarhan

A New Bivariate Distribution With Applications on Dependent Competing Risks Data

International Journal of Statistics and Probability, May 29, 2023

A new bivariate distribution is proposed in this paper using the univariate modified Weibull exte... more A new bivariate distribution is proposed in this paper using the univariate modified Weibull extension distribution. The proposed distribution is referred to as the bivariate Modified Weibull Extension (BMWE) distribution. The BMWE distribution is of Marshall-Olkin type. We discuss some of the statistical properties of the BMWE distribution. Applications of this distribution to dependent competing risks data are discussed. The maximum likelihood estimators (MLE) of the model parameters using both bivariate data and dependent competing risks data are discussed. These MLE's cannot be obtained in closed form. Therefore, numerical optimization methods are applied. A simulation study is carried out to investigate the performance of the estimation technique. Two real data sets; one bivariate data set and another dependent competing risks data set, are analyzed using the proposed distribution for illustrative and comparison purposes.

Download

Bayes inferences of the power Lindley distribution

International Journal of Reliability and Applications, 2019

Availability equivalence factors of a general repairable series-parallel system

International Journal of Reliability and Applications, Jun 1, 2013

ABSTRACT The availability equivalence factors of a general repairable series-parallel system is d... more ABSTRACT The availability equivalence factors of a general repairable series-parallel system is discussed in this paper based on the availability function of the system. The system components are assumed to be repairable and independent but not identical. The life and repair times of the system components are exponentially distributed with different parameters. Two types of availability equivalent factors of the system are derived. The results derived in this paper generalizes those given in the literature. A case study is introduced to illustrate how the idea of this work can be applied.

Parameters Estimators for the Generalized Exponential Distribution

International Journal of Reliability and Applications, Jun 1, 2007

Estimations of the Parameters in a Two-component System Using Dependent Masked Data

International Journal of Reliability and Applications, Dec 1, 2005

Modified Weibull distribution

The exponential, Rayleigh, linear failure rate and Weibull distributions are the most commonly us... more The exponential, Rayleigh, linear failure rate and Weibull distributions are the most commonly used distributions for analyzing lifetime data. These distributions have several desirable properties and nice physical interpretations. This paper introduces a new distribution named modified Weibull distribution. This distribution generalizes the following distributions: (1) exponential, (2) Rayleigh, (3) linear failure rate, and (4) Weibull. The properties of the modified Weibull distribution are discussed. The maximum likelihood estimates of its unknown parameters are obtained. A real data set is analyzed and it observed that the present distribution can provide a better fit than some other known distributions.

Download

Statistical Analysis of a Competing Risks Model with Weibull Sub-Distributions

Applied mathematics, 2017

Date initiative is launched: yyyy-mm-dd Retraction type (multiple responses allowed):  Unreliab... more Date initiative is launched: yyyy-mm-dd Retraction type (multiple responses allowed):  Unreliable findings  Lab error  Inconsistent data X Analytical error  Biased interpretation   Other:  Irreproducible results  Failure to disclose a major competing interest likely to influence interpretations or recommendations  Unethical research   Fraud   Data fabrication  Fake publication  Other:  Plagiarism  Self plagiarism  Overlap  Redundant publication *  Copyright infringement  Other legal concern:  Editorial reasons   Handling error  Unreliable review(s)  Decision error  Other:  Other: Results of publication (only one response allowed): Xare still valid.  were found to be overall invalid. Author's conduct (only one response allowed): Xhonest error  academic misconduct  none (not applicable in this case-e.g. in case of editorial reasons) * Also called duplicate or repetitive publication. Definition: "Publishing or attempting to publish substantially the same work more than once." History Expression of Concern:  yes, date: yyyy-mm-dd  no Correction:  yes, date: yyyy-mm-dd  no Comment: The following article has been retracted due to the authors' strong personal reason about the indexing databases of Applied Mathematics. This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. Aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused.

Download

Joint Structural Importance of two Components

International Journal of Reliability and Applications, Dec 1, 2002

Download

Estimation of the Parameters of the Generalized Linear Failure Rate Distribution

International Journal of Statistics and Economics, Jan 20, 2008

Recently, Sarhan and Kundu (2007) introduced a new distribution named generalized linear failure ... more Recently, Sarhan and Kundu (2007) introduced a new distribution named generalized linear failure rate distribution. This paper deals with the problem of estimating the parameters of this distribution in the case where the data is grouped and censored. We use both the maximum likelihood and Bayes techniques. The results obtained are illustrated on a set of real data.

New Generalized Weibull Distribution

In this paper, we introduce a new generalization of the Weibull distribution. This new distributi... more In this paper, we introduce a new generalization of the Weibull distribution. This new distribution generalizes several distributions, among them are the modified Weibull, the generalized linear failure rate and the exponentiated Weibull distributions. The properties of this distribution are investigated. The maximum likelihood estimates of the four unknown parameters indexed to this new distribution are obtained. A set of real data is used to explain how this new distribution can fit a real data better than some other known distributions.

Reliability Equivalence of a Non - identical Components Parallel System

International Journal of Reliability and Applications, Jun 1, 2008

Stress-strength reliability under partially accelerated life testing using Weibull model

Scientific African

A new extension of the two-parameter bathtub hazard shaped distribution

Scientific African

Statistical Inference in Connection with the Weibull Model Using Type-II Progressively Censored Data with Random Scheme

This paper discusses statistical inference in connection with a Weibull distribution model, using... more This paper discusses statistical inference in connection with a Weibull distribution model, using Type-II progressively censored data with random scheme. We used the maximum likelihood procedure to derive both point and interval estimates of the unknown parameters included in the model. The expected termination point to complete the censoring test is computed and analyzed under different censoring schemes. A numerical study is presented to illustrate the application of the theoretical results presented.

Estimations of Parameters in Multi - component Series Systems Using Masked Data

International Journal of Reliability and Applications, 2006

Estimators for Parameters Included in Cold Standby Systems with Imperfect Switches

International Journal of Reliability and Applications, 2005

A Class of Bivariate Linear Failure Rate Distributions and Their Mixtures

International Journal of Reliability and Applications, 2009

A new bivariate linear failure rate distribution is introduced through a shock model. It is prove... more A new bivariate linear failure rate distribution is introduced through a shock model. It is proved that the marginal distributions of this new bivariate distribution are linear failure rate distributions. The joint moment generating function of the bivariate distribution is derived. Mixtures of bivariate linear failure rate distributions are also discussed. Application to a real data is given.

Reliability of a k-out-of-n Cold Standby System with Imperfect Switches

International Journal of Reliability and Applications, 2001

Bayesian Analysis of the Discrete Two-Parameter Bathtub Hazard Distribution

Journal of Mathematical Sciences and Modelling, 2019

A new discrete two-parameter bathtub hazard distribution is proposed by Sarhan \cite{Sarhan-2017}... more A new discrete two-parameter bathtub hazard distribution is proposed by Sarhan \cite{Sarhan-2017}. This paper uses Bayes method to estimate the two unknown parameters and the reliability measures of this distribution. The joint posterior distribution of the model parameters cannot be obtained in a convenient form. Therefore, numerical techniques are needed. We apply four Bayesian numerical methods to get random draws from the joint posterior distribution to be used to estimate the model parameters and its reliability measures without deriving the actual joint posterior distribution. It is assumed here that the two model parameters are priori independent random variables with beta and gamma distributions. Two scenarios for the hyperparameters are applied to compare their contributions on the Bayesian inferences. Two real data sets are re-analyzed using the Bayesian techniques applied here. A simulation study is performed to investigate the properties of the methods applied.

Download

The Bivariate Generalized Rayleigh Distribution

Journal of Mathematical Sciences and Modelling, 2019

This paper introduces a new bivariate distribution named the bivariate generalized Rayleigh distr... more This paper introduces a new bivariate distribution named the bivariate generalized Rayleigh distribution (BVGR). The proposed distribution is of type of Marshall-Olkin (MO) distribution. The BVGR distribution has generalized Rayleigh marginal distributions. The joint cumulative distribution function, the joint survival function, the joint probability density function and the joint hazard rate function of the proposed distribution are obtained in closed forms. Statistical properties of the BVGR distribution are investigated. The maximum likelihood and Bayes methods are applied to estimate the unknown parameters. Both maximum likelihood and Bayes estimates are not obtained analytically. Therefore, numerical algorithms are required to report on the model parameters and its reliability characteristics. Markov Chain Monte Carlo (MCMC) algorithm is applied for the Bayesian method. A real data set is analyzed using the proposed distribution and compared it with existing distributions. It...

A New Bivariate Distribution With Applications on Dependent Competing Risks Data

International Journal of Statistics and Probability, May 29, 2023

Download

Bayes inferences of the power Lindley distribution

International Journal of Reliability and Applications, 2019

Availability equivalence factors of a general repairable series-parallel system

International Journal of Reliability and Applications, Jun 1, 2013

Parameters Estimators for the Generalized Exponential Distribution

International Journal of Reliability and Applications, Jun 1, 2007

Estimations of the Parameters in a Two-component System Using Dependent Masked Data

International Journal of Reliability and Applications, Dec 1, 2005

Modified Weibull distribution

Download

Statistical Analysis of a Competing Risks Model with Weibull Sub-Distributions

Applied mathematics, 2017

Download

Joint Structural Importance of two Components

International Journal of Reliability and Applications, Dec 1, 2002

Download

Estimation of the Parameters of the Generalized Linear Failure Rate Distribution

International Journal of Statistics and Economics, Jan 20, 2008

New Generalized Weibull Distribution

Reliability Equivalence of a Non - identical Components Parallel System

International Journal of Reliability and Applications, Jun 1, 2008

Stress-strength reliability under partially accelerated life testing using Weibull model

Scientific African

A new extension of the two-parameter bathtub hazard shaped distribution

Scientific African

Statistical Inference in Connection with the Weibull Model Using Type-II Progressively Censored Data with Random Scheme

Estimations of Parameters in Multi - component Series Systems Using Masked Data

International Journal of Reliability and Applications, 2006

Estimators for Parameters Included in Cold Standby Systems with Imperfect Switches

International Journal of Reliability and Applications, 2005

A Class of Bivariate Linear Failure Rate Distributions and Their Mixtures

International Journal of Reliability and Applications, 2009

Reliability of a k-out-of-n Cold Standby System with Imperfect Switches

International Journal of Reliability and Applications, 2001

Bayesian Analysis of the Discrete Two-Parameter Bathtub Hazard Distribution

Journal of Mathematical Sciences and Modelling, 2019

Download

The Bivariate Generalized Rayleigh Distribution

Journal of Mathematical Sciences and Modelling, 2019

Ammar Sarhan

Related Authors

Uploads

Papers by Ammar Sarhan

Log In