This case is similar to installing from an rpm file, in this case an rpm file is provided to update a previously installed version.

# su -c "yum update psad-2.1.4-1.i386.rpm"

or

# su -c "yum localupdate psad-2.1.4-1.i386.rpm"

The yum localupdate form is obsolete, use yum update from now on.