sineFit

A data frame that contains the data for one individual. There should be two columns
with names 'distance' and 'oxygen'.

data

Initial value for the amplitude parameter for the <code>method="initial"</code> method.

amplitude

Initial value for the intercept parameter for the <code>method="initial"</code> method.

intercept

A character string giving the initialization for the nonlinear least squares regression. This must be either <code>method="initial"</code> or <code>method="OLS"</code>. Default is <code>method="OLS"</code> method. <code>method="initial"</code> performs the nonlinear least squares (NLS) regression method for the cosine model without initializing parameter selections. It begins with the given initial values for amplitude and intercept. <code>method="OLS"</code> uses the least squares estimates (see Chazin et al. 2019) as the initial parameter selection.

method

This function performs the updated nonlinear least squares (NLS) regression method for the cosine model (see Chazin et al. 2019).

We introduce improved methods for statistically assessing birth seasonality and intra-annual variation. The first method we propose is a new idea that uses a nonparametric clustering procedure to group individuals with similar time series data and estimate birth seasonality based on the clusters. One can use the function SCEM() to implement this method. The second method estimates input parameters for use with a previously-developed parametric approach (Tornero et al., 2013). The relevant code for this approach is makeFits_OLS(), while makeFits_initial() is the code to implement the same method but with given initial conditions for two parameters. The latter can be used to show the disadvantage of the existing approach. One can use the function makeFits() to generate parametric birth seasonality estimates using either initialization. Detailed description can be found here: Chazin Hannah, Soudeep Deb, Joshua Falk, and Arun Srinivasan. (2019) "New Statistical Approaches to Intra-Individual Isotopic Analysis and Modeling Birth Seasonality in Studies of Herd Animals." <doi:10.1111/arcm.12432>.

sineFit: Cosine model fitting

Description

Usage

Arguments

Value

References

Examples