Dear Maarten, Ron, Joseph,
Thank you very much for the
useful commands and solutions.
I will learn how to do it
and try it.
> I'm not sure what the "significance" of a peak is,
> and I notice that  
> you have rather shyly surrounded it with quotes.
> What exactly do you  
> want to find out about the peak.
What I would like to show:
(1) whether the curve is really rising up and 
 fallind down, instead of monotonously 
 rising/falling.
(2) whether the "x" (not "y") for the peak
   is significantly different, 
   when there are two or more of such curves,
Indeed there are some mathematical models
but, when I tried to apply them by "nl",
they did not converge.
Yoshiro
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