Nonparametric signal detectability evaluation using an exponential transformation of the FROC curve

2011 ◽  
Vol 38 (10) ◽  
pp. 5690-5702 ◽  
Author(s):  
Lucretiu M. Popescu
Keyword(s):  
Exponential Transformation ◽  
Signal Detectability

Manipulating the Response Criterion in Visual Monitoring

1973 ◽  
Vol 15 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Robert C. Williges
Keyword(s):  
Signal Detection Theory ◽  
Response Criterion ◽  
Effective Response ◽  
Visual Monitoring ◽  
Subject Design ◽  
Long Duration ◽  
Ratio Condition ◽  
Signal Detectability ◽  
Over Time ◽  
Theory Interpretation

Forty-eight subjects were required to detect long-duration brightness changes (signals) and ignore short-duration changes (nonsignals) occurring on an electroluminescent panel during a 60-min. monitoring session. Signal-to-nonsignal ratios (constant 1/9, changing 1/9 to 1/1, or constant 1/1) and signal detectability (0.3 or 0.6 sec. difference between signal and nonsignal duration) were combined factorially in a between-subject design. The changing signal-to-nonsignal ratio resulted in an intermediate level of signals correctly detected. The classical decrease in percent of signals detected over time occurred in the constant 1/9 ratio condition under both levels of signal detectability. Signal detection theory analyses were restricted to low detectable signals. A marked increase in β over the monitoring session occurred in the constant 1/9 ratio condition, whereas β remained low and relatively constant in the other signal-to-nonsignal ratio conditions. Both the limitations of a decision-theory interpretation and the implications of using changing signal-to-nonsignal ratios for manipulating the observer's effective response criterion were discussed.

Evaluation of Auditory, Visual, and Dual-Mode Displays for Prolonged Sonar Monitoring in Repeated Sessions

1975 ◽  
Vol 17 (5) ◽  
pp. 425-437 ◽  
Author(s):  
W. Peter Colquhoun
Keyword(s):  
Common Factor ◽  
Visual Display ◽  
Warning Stimulus ◽  
Visual Displays ◽  
Dual Mode ◽  
Auditory Displays ◽  
Sensory Mode ◽  
Within Subjects ◽  
Signal Detectability

Using a task which closely simulated the actual output from a sonar device, the performance of 12 subjects was observed for a total of 115 hr in repeated prolonged monitoring sessions under auditory, visual, and dual-mode display conditions. Despite an underlying basic superiority of signal discriminability on the visual display, and the occurrence of long-term practice effects, detection rate was consistently and substantially higher under the auditory condition, and higher again with the dual-mode display. These results are similar to those obtained by earlier workers using artificial laboratory tasks for shorter periods, and are consistent with the notion that auditory displays have greater attention-gaining capacity in a “vigilance” situation. A further comparison of the auditory and visual displays was then made in an “alerted” situation, where the possible occurrence of a signal was indicated by a warning stimulus in the alternative sensory mode. Ten subjects were observed for a total of 57 hr in these conditions, under which performance was found to be clearly superior with the visual display. Cross-modal correlations of performance indicated the presence of a common factor of signal detectability within subjects. It was concluded that where efficiency both in the initial detection of targets and their subsequent identification and tracking are equally important, the best solution would seem to be to retain both auditory and visual displays and to ensure that these are monitored concurrently.

The Perceived Urgency and Detection Time of Multi-Tone and Frequency-Modulated Warning Signals

1993 ◽  
Vol 37 (9) ◽  
pp. 544-548 ◽  
Author(s):  
Ellen C. Haas ◽  
John G. Casali
Keyword(s):  
Pulse Interval ◽  
Measured Signal ◽  
Detection Time ◽  
Improve Performance ◽  
Warning Signals ◽  
Significant Difference ◽  
Signal Detectability ◽  
Safety Considerations ◽  
Method Of Paired Comparisons ◽  
Auditory Warning

The perceived urgency and detectability of auditory warning signals are important safety considerations. When designed correctly, auditory warning signals can improve performance and reduce accidents. However in some environments, there is a serious mismatch between the perceived (psychoacoustic) urgency of a warning and its situational urgency. In addition, many auditory warnings are not detectable within their environments. This research examined several prominent pulse parameters which affect the perceived urgency and detection time of auditory warning signals. These elements included pulse format (sequential, simultaneous, and sawtooth frequency-modulated pulses), pulse level (65 dBC and 79 dBC), and time between pulses (0 ms, 150 ms, and 300 ms). The environments of interest were those settings with steady-state broadband machinery noise. A loading task presented additional attentional demands during the signal detection task. Free-modulus magnitude estimation and the method of paired comparisons quantified perceived urgency. Simple reaction time measured signal detectability and signal effects were analyzed using a multivariate approach. Results indicated that detection time decreased as perceived urgency increased. The higher the pulse level, the greater the perceived urgency of the signal and shorter the detection time. Sequential signals were rated as less urgent than the other pulse formats, and subjects took longer to detect their occurrence. Under most conditions, there was no significant difference in the perceived urgency or detection time of simultaneous and frequency-modulated pulses. Time between pulses (inter-pulse interval) affected only perceived urgency, not detection time. The shorter the time between pulses, the greater the perceived urgency of the signal.

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