اکثر مکاتبات کومش از طریق ایمیل سایت می باشد. لطفا Spam ایمیل خود را نیز چک نمایید.
   [Home ] [Archive]   [ فارسی ]  
:: ::
Main Menu
Home::
Journal Information::
Articles archive::
For Authors::
Subscription::
Contact us::
Site Facilities::
Webmail::
Editorial Board::
::
Search in website

Advanced Search
..
Receive site information
Enter your Email in the following box to receive the site news and information.
..
:: Volume 19, Issue 2 (بهار 1396، شماره 19 (2). 1396) ::
Koomesh 1396, 19(2): 371-379 Back to browse issues page
Comparison of parametric and semi-parametric methods for estimation of the parameters in frailty models in order to investigation effective factors in survival of the dental implants placement
Hossein Hosseinifard , Ahmad Reza Baghestani , Mohammad Jafarian , Mohammad Bayat , Sayna Shamszadeh , Alireza Akbarzadeh Baghban
Abstract:   (5346 Views)
Introduction: Frailty models were utilized in survival models to take into account created heterogeneity and dependence between experimental units. Parametric and semi-parametric methods are considered for estimation of parameters in frailty models. In parametric frailty models, to frailty and baseline hazard, a parametric distribution is assumed, while the distribution for baseline hazard function is not considered in semi-parametric methods. Besides, the parameters using EM algorithm or penalized likelihood are estimated in the mentioned methods. The purpose of this study is the comparison of parametric and semi-parametric methods in frailty models. Materials and Methods: Two hundred thirteen of the warfare victims that treated with dental implants during 2000 to 2010 were enrolled in this study. In order to investigation effective factors in survival of the dental implants placement, frailty models are fitted. Parameters are estimated using the three methods, parametric approach, semi- parametric using EM algorithm and Semi parametric using penalized likelihood. Statistical analysis was carried out using Frailtypack package in R software version 3.3.1. Results: Estimation of the semi parametric using penalized likelihood approach is contained a smaller magnitude of AIC as compared to parametric and semi-parametric approach of EM algorithm. Smoking and implant length are significant factors on survival implants (p
Keywords: Survival Analysis, Statistical Models, Algorithms, Likelihood Functions, Dental Implants
Full-Text [PDF 737 kb]   (1552 Downloads)    
Type of Study: Research | Subject: General
Received: 2016/06/21 | Accepted: 2016/12/19 | Published: 2017/03/15
Send email to the article author

Add your comments about this article
Your username or Email:

CAPTCHA


XML   Persian Abstract   Print


Download citation:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:

hosseinifard H, Baghestani A R, Jafarian M, Bayat M, Shamszadeh S, Akbarzadeh Baghban A. Comparison of parametric and semi-parametric methods for estimation of the parameters in frailty models in order to investigation effective factors in survival of the dental implants placement. Koomesh 1396; 19 (2) :371-379
URL: http://koomeshjournal.semums.ac.ir/article-1-3399-en.html


Rights and permissions
Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Volume 19, Issue 2 (بهار 1396، شماره 19 (2). 1396) Back to browse issues page
کومش Koomesh
Persian site map - English site map - Created in 0.06 seconds with 38 queries by YEKTAWEB 4645