NCJ Number
117858
Date Published
1988
Length
5 pages
Annotation
A major improvement in outdoor perimeter security system probability of detection and reduction in false alarm rate and nuisance alarm rate may be obtained by analyzing the indications immediately preceding an event which might be interpreted as an intrusion.
Abstract
Existing systems go into alarm after crossing a threshold. Very slow changes, which accumulate until the threshold is reached, may be assessed falsely as an intrusion. The ability to "look into the past" on a real-time basis adds a new dimension to alarm reporting and monitoring. This is done by converting analog data to digital data and storing it in serial form in memory. Since this stored data may be accessed and transmitted in reverse order, the immediate pre-trigger event history would be available for alarm decision making. 2 figures, 4 references. (Author abstract modified)