Package: appac
Title: Atmospheric Pressure Peak Area Correction for Gas Chromatography
        with Standard Detectors
Version: 4.0.3
Authors@R: 
    person("Ruediger", "Forster", , "meticulous.measurements@gmail.com",
           role = c("aut", "cre"),
           comment = c(ORCID = "0009-0006-4851-7430"))
Description: Corrects gas-chromatography peak areas for the influence of ambient
    air pressure on standard detectors open to the ambient atmosphere, such as
    the flame ionization detector, whose pressure sensitivity was
    characterised by Bocek, Novak and Janak (1969)
    <doi:10.1016/S0021-9673(00)99223-9>. Unlike the pressure compensation of
    Ayers and Clardy (1985) <https://patents.google.com/patent/US4512181A>, which
    is combined with a calibration and valid only for a single calibration period
    of a few days, per-cylinder peak areas are decomposed by principal components
    into a pressure-correlated component and per-peak drift; a common
    pressure-sensitivity coefficient (kappa) is estimated with a heavy-tail-robust
    fit on a drift-reduced signal, and slow drift plus a daily factor are removed.
    Returns the corrected areas together with a chi-square goodness-of-fit
    diagnostic. Structural-break detection (package 'strucchange', Zeileis and
    others (2002) <doi:10.18637/jss.v007.i02>) is provided for episode-level and
    variance breakpoint analysis.
License: GPL-3
Encoding: UTF-8
Depends: R (>= 4.0.0)
Imports: methods, stats, utils, data.table, dplyr, tibble, purrr, kza,
        robustbase, strucchange
Suggests: ggplot2, patchwork, knitr, rmarkdown, testthat (>= 3.0.0)
VignetteBuilder: knitr
Config/testthat/edition: 3
LazyData: true
Config/roxygen2/version: 8.0.0
NeedsCompilation: no
Packaged: 2026-07-06 18:31:49 UTC; ruedi
Author: Ruediger Forster [aut, cre] (ORCID:
    <https://orcid.org/0009-0006-4851-7430>)
Maintainer: Ruediger Forster <meticulous.measurements@gmail.com>
Repository: CRAN
Date/Publication: 2026-07-15 18:00:02 UTC
Built: R 4.7.0; ; 2026-08-18 03:32:51 UTC; windows
