False Alarm Reduction Research Articles

Survey of expert systems for fault detection, test generation and maintenance

Abstract: The use of knowledge engineering in diagnostic systems, is aimed primarily at exploiting procedural knowledge (about: systems operations, configuration, observations, calibration, maintenance), in connection with failure detection and test generation tasks. Next, the goal is to devise knowledge representation schemes whereby the failure events can be analyzed by merging highly diverse sources of information: analog/digital signals, logical variables and test outcomes, text from verbal reports, and inspection images. The final goal is to ease the operator workload when interfacing with the system under test and/or the test equipment, or with reliability assessment software packages. The paper will present key notions, methods and tools from: knowledge representation, inference procedures, pattern analysis. This will be illustrated by reference to a number of current and potential applications for e.g.: electronics failure detection, control systems testing, analysis of intermittent failures, false alarm reduction, test generation, maintenance trainers.

2-D wavelength multiplex correlator

A correlator working a multiline coherent source is demosntrated. Each of the wavelengths acts as an independent channel and generates achromatic correlation peaks. A comparison between experimental results obtained in monochromatic and polychromatic light indicates that a reduction of false alarms in pattern recognition is expected.

Economic justification of tsunami research: A specific example based on reduction of false alarms in Hawaii

The most significant potential improvement to the Tsunami Warning System, at least as it affects Hawaii, and one of the more important practical justifications of tsunami research, is the reduction in false alarms. There are both immediate and deferred costs of tsunami false alarms. The immediate costs are the costs of responding to tsunami warnings, false or not. The deferred costs are the tsunami casualties resulting from failures to respond to subsequent warnings, insofar as these are attributable to the loss of public confidence in the warning system due to the false alarms. It is estimated that the Hawaiian response to a tsunami false alarm costs about $777,000, and that with present warning system policy the average annual costs of such responses is $264,000. Assigning values to human life and injury, it is estimated that the deferred costs of false alarms average about $42,000 per year, bringing the total annual costs to $306,000. An 80% reduction of these costs would justify an annual research exp...

Quantitative cytology of the positive region in flow sorted vaginal smears.

Fifty-one gynecologic specimens were collected from three women's hospitals and mailed in a prefixed status to our laboratory. The specimens were classified into a negative, a suspicious, a postradiation, and a positive group. After single cell dispersion the samples were stained for DNA and protein, analyzed, and sorted in the dual laser equipped Heidelberg flow analyzer sorter (HEIFAS). Particles with elevated DNA values (beyond 3.5 ploidy) and with intermediate protein values were sorted as the positive fraction directly on microscopic slides. After restaining according to Papanicolaou, they were re-evaluated cytologically and identified as tumor cells, dysplastic cells and false alarms. The latter consist of doublets and aggregates of more than two cells, binucleated cells, sperm aggregates and epithelial cells contaminated with bacteria. The different groups showed significant differences regarding the total rate of aggregates to single cells. In general, false alarms were very frequent in the positive region and impeded the statistical classification of the sample. The reduction of false alarms is a prerequisite for prescreening with flow instrumentation.

The application of signal detection theory to letter recognition

Signal Detection measures were used to assess tachistiscopic recognition of single target letters or pairs of targets, embedded in strings of non-targets whose shapes were eithor similar or dissimilar to the targets. Sensitivity was worse, and there was a stronger response bias towards reporting targets, when similar non-targets were used. Ss who were informed about the nature of the non-targets showed little change in sensitivity, but a marked reduction in false alarms with similar non-targets.

Effects of information feedback and reference tones on signal detection

In an auditory signal detection study feedback and no-feedback conditions were compared and the effect of introducing anchor or reference tones during the intertrial interval was investigated. Feedback increased the proportion of correct detections as did the presence of a strong anchor. The latter condition was also associated with a reduction of false alarms.