Package: GammaFrailtySPC
Type: Package
Title: Statistical Process Control Based on Gamma-Frailty AFT Models
Version: 0.1.0
Authors@R: c(
    person("Shikhar", "Tyagi",
        email = "shikhar1093tyagi@gmail.com",
        role = c("aut", "cre"),
        comment = c(ORCID = "0000-0003-1606-0844")),
    person("Arvind", "Pandey",
        email = "arvindmzu@gmail.com",
        role = "aut"),
    person("Bhupendra", "Singh",
        email = "bhupendra.rana@gmail.com",
        role = "aut"),
    person("Vrijesh", "Tripathi",
        email = "vrijesh.tripathi@uwi.edu",
        role = "aut"))
Description: Implements statistical process control ('SPC') monitoring schemes
    for heterogeneous reliability observations using Accelerated Failure Time
    ('AFT') models integrated with continuous gamma frailty. It accommodates both
    uncensored and right-censored reliability observations in the presence of
    observed and unobserved covariates. Provides Phase I maximum likelihood
    estimation of Weibull 'AFT' gamma frailty model parameters, and Phase II
    monitoring procedures including probability-limits-based control charts,
    exponentially weighted moving average ('EWMA') charts with conditional
    expected values, and likelihood-ratio cumulative sum ('CUSUM') control
    charts. Competing 'CUSUM' schemes (ignoring unobserved frailty or both
    covariates) and Average Run Length ('ARL') simulation utilities are also
    provided. The statistical methodology is based on Asadzadeh (2022)
    <doi:10.1080/00949655.2021.1959582>.
License: GPL-3
Depends: R (>= 4.0.0)
Imports: maxLik, survival, stats, graphics, grDevices, utils
Suggests: testthat (>= 3.0.0), knitr, rmarkdown
Config/testthat/edition: 3
Encoding: UTF-8
Language: en-US
LazyData: true
RoxygenNote: 7.3.3
VignetteBuilder: knitr
NeedsCompilation: no
Packaged: 2026-08-03 20:59:39 UTC; shikhar tyagi
Author: Shikhar Tyagi [aut, cre] (ORCID:
    <https://orcid.org/0000-0003-1606-0844>),
  Arvind Pandey [aut],
  Bhupendra Singh [aut],
  Vrijesh Tripathi [aut]
Maintainer: Shikhar Tyagi <shikhar1093tyagi@gmail.com>
Repository: CRAN
Date/Publication: 2026-08-08 13:50:16 UTC
