Exponential smoothing of aperiodically measured values with staleness reporting

1. A computer-readable medium having a computer program stored thereon comprising executable instructions for performing an aperiodic noisy measurement method comprising:

setting a fixed time interval;

waiting for the time interval to expire or for a noisy measurement to occur;

when the noisy measurement occurs, calculating a first numerator as a numerator of a previous noisy measurement plus the noisy measurement and calculating a first denominator as a denominator of the previous noisy measurement plus one;

calculating a second numerator as the first numerator times a step size and calculating a second denominator as the first denominator times the step size;

estimating a staleness measurement from the second denominator; and

calculating an estimate of the noisy measurement as the second numerator divided by the second denominator.

2. The computer-readable medium of claim 1 further comprising executable instructions for discarding the estimate when the staleness measurement exceeds a threshold.

3. The computer-readable medium of claim 1 further comprising executable instructions for causing measurements to be taken when the staleness measurement exceeds a threshold.

4. The computer-readable medium of claim 1 further comprising executable instructions for setting an initial value of the staleness measurement as infinite when no prior estimate of the measurement is available.

5. The computer-readable medium of claim 1 further comprising executable instructions for setting the numerator and denominator in accordance with a parameter of an available measurement.

6. The computer-readable medium of claim 5 further comprising executable instructions for setting the second denominator according to a confidence in the estimate and setting the second numerator as the second denominator times the estimate.

7. The computer-readable medium of claim 1 further comprising executable instructions for setting a staleness threshold according to (1−α) τ where τ is a quotient of a staleness period and an alarm period and α is the step size.

8. The computer-readable medium of claim 1 wherein the staleness measurement is estimated as the inverse of the second denominator.

9. A computer-readable medium having a computer program stored thereon comprising executable instructions for aperiodically estimating a temperature comprising:

setting a time interval;

waiting for the time interval to expire or for a measurement of temperature to occur;

when the measurement of temperature occurs, calculating a first numerator as a numerator of a previous temperature measurement plus the temperature measurement and calculating a first denominator as a denominator of the previous temperature measurement plus one;

calculating a second numerator as the first numerator times a step size and calculating a second denominator as the first denominator times the step size;

estimating a staleness measurement from the second denominator; and

calculating an estimate of the temperature as the second numerator divided by the second denominator.

10. The computer-readable medium of claim 9 further comprising executable instructions for discarding the estimate when the staleness measurement exceeds a threshold.

11. The computer-readable medium of claim 9 further comprising executable instructions for causing measurements to be taken when the staleness measurement exceeds a threshold.

12. The computer-readable medium of claim 9 further comprising executable instructions for setting an initial value of the staleness measurement as infinite when no prior estimate of the measurement is available.

13. The computer-readable medium of claim 9 further comprising executable instructions for setting the first numerator and the first denominator in accordance with a parameter of an available measurement.

14. The computer-readable medium of claim 13 further comprising executable instructions for setting the second denominator according to a confidence in the estimate and setting the second numerator as the denominator times the estimate.

15. The computer-readable medium of claim 9 further comprising executable instructions for setting a staleness threshold according to (1−α) τ where τ is a quotient of a staleness period and an alarm period and α is the step size.

16. The computer-readable medium of claim 9 wherein the staleness measurement is estimated as the inverse of the second denominator.

17. A computer-readable medium having a computer program stored thereon comprising executable instructions for aperiodically predicting I/O response times comprising:

setting a fixed time interval;

waiting for the time interval to expire or for an I/O response time measurement to occur;

when the I/O response time measurement occurs, calculating a first numerator as a numerator of a previous I/O response time measurement plus the I/O response time measurement and calculating a first denominator as a denominator of the previous I/O response time measurement plus one;

calculating a second numerator as the first numerator times a step size and calculating a second denominaotr as the first denominator times the step size;

estimating a staleness measurement from the second denominator; and

calculating an estimate of the I/O measurement response time as the second numerator divided by the second denominator.