Periodic inspection observation scheme

Creates an observation functor for periodic inspections at intervals of delta. Failures are bracketed between the last inspection before failure and the first inspection after failure (interval-censored). Systems surviving past tau are right-censored.

Usage

observe_periodic(delta, tau = Inf)

Arguments

delta

inspection interval (positive numeric)

tau

study end time (positive numeric or Inf for no right-censoring)

Value

A function with signature function(t_true) returning a list with components:

t

lower bound of interval (or tau if right-censored)

omega

"interval" or "right"

t_upper

upper bound of interval (NA if right-censored)

Examples

obs <- observe_periodic(delta = 10, tau = 100)
obs(25)   # interval: list(t = 20, omega = "interval", t_upper = 30)
#> $t
#> [1] 20
#> 
#> $omega
#> [1] "interval"
#> 
#> $t_upper
#> [1] 30
#> 
obs(150)  # right-censored: list(t = 100, omega = "right", t_upper = NA)
#> $t
#> [1] 100
#> 
#> $omega
#> [1] "right"
#> 
#> $t_upper
#> [1] NA
#>