Changes in version 0.2.1 (2026-10-07)                  

New Models

Added two new nonlinear gas production models:

  - Burr XII
  - Inverse Paralogistic

Burr XII

Equation:

V(t) = VF [1 - (1 + (rt)^a)^(-p)]

Features:

  - Flexible four-parameter sigmoidal model
  - Accommodates diverse fermentation profiles
  - Supports asymmetry and variable inflection behavior
  - Useful for comparative model-selection studies

Inverse Paralogistic

Equation:

V(t) = VF [1 + (rt)^(-a)]^(-a)

Features:

  - Flexible three-parameter sigmoidal model
  - Biologically interpretable asymptote
  - Strong performance across diverse fermentation profiles

Documentation Improvements

Model Reference Vignette

Updated the "Model Equations Reference" vignette:

  - Added Burr XII documentation
  - Added Inverse Paralogistic documentation
  - Added model-selection guidance
  - Expanded model-equivalence discussion

Model Interpretation Vignette

Updated the "Interpreting Gas Production Models" vignette:

  - Added interpretation of Burr XII parameters
  - Added interpretation of Inverse Paralogistic parameters
  - Expanded discussion of shape parameters
  - Added model-equivalence interpretation
  - Added practical model-selection guidance

Getting Started Vignette

Updated the "Getting Started with rumenGP" vignette:

  - Added Burr XII examples
  - Added Inverse Paralogistic examples
  - Expanded model-comparison workflow
  - Added model-selection recommendations

Importing Non-ANKOM Data Vignette

Updated the "Importing Non-ANKOM Data" vignette:

  - Added examples using newly implemented models
  - Expanded model-comparison examples
  - Added model-equivalence notes

Model Equivalence Documentation

Documented the mathematical equivalence of:

  - Groot
  - Generalized Michaelis-Menten
  - Log-logistic

Parameter correspondence:

  - VF = A = VF
  - b = K = 1/r
  - k = c = a

Clarified that these models represent mathematically equivalent
parameterizations of the same underlying sigmoidal gas-production curve
for positive values of time.

Documented differences in the handling of time-zero observations,
including the exclusion of Time_h = 0 when fitting the Groot model
because the formulation is undefined at (t = 0), and the retention of
time-zero observations in the Generalized Michaelis-Menten and
Log-logistic formulations.

rumenGP now implements all three parameterizations, allowing researchers
to select the formulation most appropriate for their field while
recognizing their underlying mathematical equivalence.

README Improvements

Updated package documentation:

  - Added Burr XII
  - Added Inverse Paralogistic
  - Documented model equivalence
  - Expanded model-comparison examples
  - Added recommended model-selection workflow
  - Updated built-in model count

Package Content

Current built-in model library:

  - Brody
  - Burr XII
  - Dual Logistic
  - EXP0
  - EXPL
  - Generalized Michaelis-Menten
  - Gompertz
  - Groot
  - Inverse Paralogistic
  - LE0
  - LEL
  - Logistic
  - Log-logistic
  - Mitscherlich
  - Ørskov and McDonald

Total:

  - 15 built-in kinetic models

Quality Assurance

  - Updated package documentation throughout
  - Updated package website content
  - Updated vignettes
  - Updated examples
  - Maintained clean package checks

R CMD check:

  - 0 errors
  - 0 warnings
  - 0 notes