% The function rand_int_breath.m determines the time in which the next
% respiratory cycle will be initiated during random-interval breathing.
% This time, which is determined according to an independent probability
% experiment governed by a modified exponential pdf, may range from one
% to 15 seconds with a mean of five seconds (Berger et. al., 1989).
%
% Function arguments: none
%
% Function outputs:
%	t - time of initiation of next respiratory cycle
%

function t = rand_int_breath

% Assigning variables.
lambda = 0.2083;
tmin = 1;
tmax = 15;

% Computing the time of the initiation of the next respiratory cycle.
k = 1/(1 - exp(-lambda*(tmax-tmin)));
t = tmin - (1/lambda)*log(1-(rand(1)/k));