Ming-Shun Chang 
my 
[es dw 
» ett 7 4s0 
1) 26. 84 0 
| S(w) dw 
0 
T (1. 6) 
ain ae fs) as a 
0 
The statistics of T, and Hy, , p(T, » Hays ), are then constructed 
from these calculated values with equal weights. The averaged idea- 
lized spectrum was calculated from equations (1.5), (1.2), and 
p(T, » Hy ). 
The resulting averaged idealized spectrum was compared 
with the averaged hindcast spectrum S,(w) of those 23,360 spec- 
tra ; that is 
23,360 
i=1 
where So:(~) are the hindcast spectra. As seen in Figure l, the 
comparisons do not agree very well. In comparison to the averaged 
hindcast spectrum, the idealized spectrum does not contain enough 
energy over both the high frequency and very low frequency range, 
and is high for the middle frequency band. Figure 2 shows the pro- 
bability diagram constructed from the statistics of T, and H,, of 
the hindcast wave data. For illustration purposes, Figures 3 and 4 
show the corresponding purely imaginary family of responses which 
result from assuming that 
Cc 4 
= 2 * 
g(T,, Hy /,) pe. He uyahd poten exp(-2T,/T, ) 
where C and T,* are constants. The curves of response for a =0.1C 
and 0.4C are shown in the figures. With Tt = 10 sec the probabili- 
ty that the response would exceed 0.4C and 0.1C was estimated as 
1 percent and 17 percent, respectively, by measuring the areas. The 
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