Why it matters
It converts a measurement into a decision window. A threshold tells you a hazard has arrived; a time to threshold tells you roughly how long you have to prevent it arriving.
Prediction & analysis
Time to threshold
Time to threshold is an estimate of how long a monitored channel will take to reach its alarm limit if its current trend continues.
How it works
A trend line is fitted to a recent window of readings, usually by least squares. If the slope is positive and the limit is above the current value, the projected intersection gives the estimate.
Example
A channel at 400 rising at 10 units per minute with a limit of 700 yields an estimate of about thirty minutes.
In Alfa HazardX
Computed server-side from stored readings, where there is more history than the node holds.
Read further
Related terms
- Baseline deviationBaseline deviation measures how far a current reading has moved from what is normal for that specific sensor in that specific location.
- Z-scoreA z-score expresses how many standard deviations a value sits from the mean of its distribution, making deviations comparable across channels with different units and scales.
- Deterministic analysisDeterministic analysis produces the same output for the same input every time, using explicit rules or arithmetic rather than a learned model.