BC.negative.reg.RST {RoughSets} | R Documentation |
Computation of a negative region
Description
This function implements a fundamental part of RST: computation of a negative region and the
degree of dependency. This function can be used as a basic building block for development
of other RST-based methods. A more detailed explanation of this notion can be found
in Introduction-RoughSets
.
Usage
BC.negative.reg.RST(decision.table, roughset)
Arguments
decision.table |
an object inheriting from the |
roughset |
an object inheriting from the |
Value
An object of a class "NegativeRegion"
which is a list with the following components:
-
negative.reg
: an integer vector containing indices of data instances belonging to the boundary region, -
degree.dependency
: a numeric value giving the degree of dependency, -
type.model
: a varacter vector identifying the utilized model. In this case, it is"RST"
which means the rough set theory.
Author(s)
Dariusz Jankowski, Andrzej Janusz
References
Z. Pawlak, "Rough Sets", International Journal of Computer and Information Sciences, vol. 11, no. 5, p. 341 - 356 (1982).
See Also
BC.IND.relation.RST
, BC.LU.approximation.RST
, BC.LU.approximation.FRST
Examples
########################################################
data(RoughSetData)
hiring.data <- RoughSetData$hiring.dt
## We select a single attribute for computation of indiscernibility classes:
A <- c(2)
## compute the indiscernibility classes:
IND.A <- BC.IND.relation.RST(hiring.data, feature.set = A)
## compute the lower and upper approximation:
roughset <- BC.LU.approximation.RST(hiring.data, IND.A)
## get the boundary region:
pos.negative = BC.negative.reg.RST(hiring.data, roughset)
pos.negative