Importance of . (period)
whenever I look at mails from my friends, most of them compose mails without period after completing a sentence. Even if mails meant for friendly discussion or something, we should not neglect the importance of period. It will give good appeal to the reader. Many of my friends used to send mails like this:

Hi ra...
How are you...
here v r njoying a lot...
no mails from you...
bye..
------

Hi ra..
How r u?.. I am coming to bombay this weekend.. ok then catch u later...
bye
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This is simply because of some kind of lazyness in composing mails or may be "... " indicates a short break in conversation. Yes right!! A short break in conversation.

Compensator Design:
System Type :
input = A/s^q ; System type = G/s^N;
If N = q-1 ; finite amount of steady state error.
N > q-1; zero steady state error.
N < q-1 steady state error is infinite.
'N' should be satisfied before getting into design details.

Open loop poles tend to repel the branches of the root locus and open loop zeros tend to attract the root locus. So a lead compensator [------x-----o---] will try to pull the root locus (poles sitting at origin)towards left half plane. Stability is improved.
Same case with lag compensator- [-----o-----x----] will push the root locus away from the left half plane.