Methods and systems for forecasting with model-based PDF estimates
View Patent ↗Disclosed herein are systems and methods for forecasting with model-based PDF (probability density function) estimates. Some method embodiments may comprise: estimating model parameters for a time series, calculating a PDF for the time series, and generating a forecast from the PDF. The model parameters may comprise a variance for a hidden noise source, and the PDF for the time series may be based at least in part on an estimated variance for the hidden noise source.
1. A computer-readable storage medium storing a program that, when executed by a processor, causes the processor to:
select a reference set of profiles from previous periods;
estimate model parameters of a time series based on the reference set, wherein the model parameters comprise a first variance for a hidden noise source;
calculate a probability density function for the time series including determining a second variance for the probability density function based at least in part on the first variance for the hidden noise source; and
generate a forecast from the probability density function.
2. The computer-readable storage medium of claim 1 , wherein when the processor estimates, the program further causes the processor to differentiate the time series to obtain a stationary time series.
3. The computer-readable storage medium claim 1 , wherein when the processor estimates, the program further causes the processor to estimate using model parameters comprising coefficients of a moving average filter.
4. The computer-readable storage medium of claim 1 , wherein when the processor estimates, the program further causes the processor to estimate using model parameters comprising coefficients of an autoregressive filter.
5. The computer-readable storage medium of claim 1 , wherein when the processor estimates, the program further causes the processor to estimate using model parameters comprising an offset value.
6. The computer-readable storage medium of claim 1 , wherein when the processor estimates, the program further causes the processor to estimate using model parameters where the model accounts for recurring patterns in the time series.
7. The computer-readable storage medium of claim 1 , wherein when the processor calculates, the program further causes the processor to calculate a Gaussian probability density function.
8. The computer-readable storage medium of claim 1 , wherein when the processor calculates, the program further causes the processor to calculate the probability density function being a function of time.
9. The computer-readable storage medium of claim 1 , further comprising:
wherein when the processor estimates the time series, the program further causes the processor to estimate the time series representing a cumulative value; and
wherein when the processor generates the forecast, the processor generates the forecast being an end-of-period cumulative value.
10. A computer comprising:
a display;
a processor coupled to the display; and
a memory coupled to the processor,
wherein the memory stores software that configures the processor to:
select reference profiles from a set of profiles from previous periods;
estimate a time series based on the reference profiles and a profile of the current period; and
derive a probability density function for the time series by estimating parameters of a model that comprises a hidden noise source,
wherein the software configures the processor to determine a first variance for the hidden noise source, and wherein the software further configures the processor to determine a second variance for the probability density function from the first variance of the hidden noise source and from estimated filter coefficients.
11. The computer-readable storage medium of claim 1 wherein when the processor changes the profiles, the program further causes the processor to perform a dissimilarity calculations between the profile of the current period, and to change the profiles in the reference set based on the dissimilarity calculations.