looks like i (or ubuntu) have a problem to set ulimits for users ( not admin user ).
here is my configuration of limits.conf:

how to set the ulimit as admin for another user.
/etc/security/limits.conf seems not working ( even after reboot )
here my configuration of limits.conf
#<domain> <type> <item> <value>
#* soft core 0
#root hard core 100000
#* hard rss 10000
#@student hard nproc 20
#@faculty soft nproc 20
#@faculty hard nproc 50
#ftp hard nproc 0
#ftp - chroot /ftp
#@student - maxlogins 4
test soft data 512000
test hard data 614000
test soft stack 8192
test hard stack 16384
test soft as 512000
test hard as 614000

after login as user test ulimit -a gives me:
testuser@tschang:~/src/test$ ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 28962
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192

my question is - is it my mistake or is it a bug ?????