markbouts.acclist: Classify accumulation of physical activity in bouts
In pawacc: Physical activity with accelerometers

Description Usage Arguments Details Value Author(s) See Also

This function identifies bouts of physical activity using user-defined breakpoints for accelerometer counts.

markbouts(object, value, which = "counts", bts = c(0, 10, 20, Inf), rescale.epoch = 60,
collapse.by = "%Y-%m-%d", value.labels = NULL, bouts.labels = NULL,
extreme = NULL, keep.error = FALSE)
## S3 method for class 'acclist'
markbouts(object, value, which = "counts", bts = c(0, 10, 20, Inf), rescale.epoch = 60,
collapse.by = "%Y-%m-%d", value.labels = NULL, bouts.labels = NULL,
extreme = NULL, keep.error = FALSE)
## S3 method for class 'accfile'
markbouts(object, value, which = "counts", bts = c(0, 10, 20, Inf), rescale.epoch = 60,
collapse.by = "%Y-%m-%d", value.labels = NULL, bouts.labels = NULL,
extreme = NULL, keep.error = FALSE)

`object`	an object of class `acclist` or `accfile`.
`value`	vector of breaks to define physical activity modes. The lowest breakpoint must be 0.
`which`	either 'counts' or 'steps' for `gt1m` files or one of `c('x','y','z','steps')` for `gt3x` files.
`bts`	vector of breaks to define bouts duration (in minutes).
`rescale.epoch`	epoch expressed in the same unit as acceleromenter's epoch to determine multiplier to rescale `value` (default is 60). See details.
`collapse.by`	dataset aggregation level. See argument `format` from `strptime` for options and details below.
`value.labels`	labels for physical activity modes.
`bouts.labels`	labels for bouts duration catergories (`NULL` is recommended).
`extreme`
`keep.error`	logical flag. If `FALSE` (default) data errors as identified by `errorChk` will be replaced by NAs.

Breakpoints are specified as counts per seconds using value. If the epoch used for value is different from the accelerometer's epoch, a rescaling is applied. E.g., if epoch is 15 seconds and breakpoints are expressed as counts per 60 seconds, value is divided by 60/15 = 4. There can be n physical activity modes at maximum, where n is the length of value.

The argument extreme is NULL by default. Use either ‘last’ to select the last category or the category number 1 to n.

The function markbouts.accfile returns duration, frequency and mean duration of bouts by bout category, physical activity mode and T levels of collapse.by (e.g., day) in array of dimension c(length(bts) - 1,length(value) + 1,3,T). markbouts.acclist is applied to objects of class acclist, in which case a list of arrays of the same length as the number of accelerometer files in object is returned.

Marco Geraci

readAccDir

pawacc documentation built on May 2, 2019, 5:20 p.m.