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False alarms may occur with residential burglary alarms, smoke detectors, industrial alarms, fire alarms and in signal detection theory. False alarms have the potential to divert emergency responders away from legitimate emergencies, which could ultimately lead to loss of life. In some cases, repeated false alarms in a certain area may cause ...
The false positive rate is calculated as the ratio between the number of negative events wrongly categorized as positive (false positives) and the total number of actual negative events (regardless of classification). The false positive rate (or "false alarm rate") usually refers to the expectancy of the false positive ratio.
However, in most fielded systems, unwanted clutter and interference sources mean that the noise level changes both spatially and temporally. In this case, a changing threshold can be used, where the threshold level is raised and lowered to maintain a constant probability of false alarm. This is known as constant false alarm rate (CFAR) detection.
In addition, false alarms may acclimatise people to ignore alarm signals, and thus possibly to ignore an actual emergency: Aesop's fable of The Boy Who Cried Wolf exemplifies this problem. A false alarm is one of the most significant issues with conventional alarm systems. They can be triggered for several reasons, such as the movement of pets ...
An airline spokesperson said an indicator light was later confirmed to be false. An American Airlines jet made an emergency landing Sunday after the crew reported a "possible electric issue."
The L.A. County Fire Department determined that a reported plane crash off Rancho Palos Verdes was a false alarm and ended their search around 6:30 p.m. Wednesday, authorities said.
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On January 13, 2018 at approximately 8:07 a.m. HST, the Hawaii Emergency Management Agency (HI-EMA) mistakenly issued an emergency alert warning of a ballistic missile inbound threatening the region, which was claimed to be not a drill. 38 minutes later, it was announced by HI-EMA and the Honolulu Police Department that the alert was a false alarm.