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Let [$]v(t)[$] be the function of the instantaneous variance of an underlying stock or index between the open and close of an exchange, normalized by the total variance. I think this is called variance schedule. How is [$]v(t)[$] used, particularly in options pricing/trading/market making?

I understand that the [$]v(t)[$] integrated over a time period can be plugged into some model, say Black-Scholes formula to obtain an option price. I was told that some effective variance-time can be obtained from this variance distribution. How is that used?