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Monte Carlo Analysis<br />

Primary Statistics of Uncertainty Analysis<br />

The value of this upper bound in the above example is:<br />

Importance Sampling Monte Carlo efficiently handles these cases of low failure probabilities.<br />

Quantile Estimators using Standard Monte Carlo<br />

The first MCBOUND extracts are modified as follows:<br />

.EXTRACT MC LABEL=quantile_fosc_left_1em4 MCBOUND(fosc, 1e-1)<br />

.EXTRACT MC LABEL=quantile_phn_right_1em4 MCBOUND(phase_noise_1meg,1.0 -<br />

1e-1)<br />

The target probabilities in the left tail of the frequency FOSC and the right tail of the phase<br />

noise are shifted to the “normal events” domain. These specifications can be simulated more<br />

easily using the standard Monte Carlo method. Running Eldo with SAMPLING=RAND and<br />

5000 runs produces a .mcm file containing the following data:<br />

Tail Probability Lower Quantile Upper Prec(%) Name<br />

(Goal Value) Value of Meas<br />

--------------------------------------------------------------------------------<br />

Left 1.000e-01 1.80857e+09 1.80963e+09 1.81042e+09 0.10% FOSC<br />

Right 9.000e-01 -1.17933e+02 -1.17911e+02 -1.17887e+02 0.04% PHASE_N<br />

The lower and upper bounds are obtained by inverting the confidence interval:<br />

where π is the target probability, and where h is the half-range of the confidence interval:<br />

A theoretical result ensures that a central limit theorem exists for quantiles.<br />

Probability and Quantiles using Importance Sampling Monte Carlo<br />

Running Eldo with SAMPLING=ISMC and 500 runs for each batch produces a .mcm file<br />

containing the following data:<br />

Eldo® User's Manual, 15.3 483

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