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.

The Role of Payoffs and Signal Ratios in Criterion Changes during a Monitoring Task

1971 ◽  
Vol 13 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Robert C. Williges
Keyword(s):  
Signal Detection Theory ◽  
False Alarms ◽  
Signal Ratio ◽  
Monitoring Task ◽  
Decision Performance ◽  
Signal Rate ◽  
Subject Design ◽  
Long Duration ◽  
Over Time

Forty-eight subjects detected a long-duration (1.7 or 1.3 sec.) change in brightness (from a 5 ft.-l. standard to a 4 ft.-l. level) of an electroluminescent panel during a 60-min. monitoring session. Signal/nonsignal ratios (1/9 or 1/1) and payoffs (lax, neutral, or strict) were combined factorially in a between-subject design. Signal ratios affected both the percent of signal detections and the percent of false-alarm errors. When subjects monitored under the lower signal ratios, a decrease in percent of signal detections occurred over time. Payoffs affected only the percent of false alarms in the higher signal rate conditions. Signal detection theory analyses resulted in a slight decrease in d' and a marked increase in β during the watch period. The change in β was due primarily to the lower signal ratio conditions. Payoffs had no effect on subsequent β change. It was concluded that signal ratios rather than payoffs play the major role in determining decision performance in simple visual monitoring tasks.

scholarly journals Hazard Perception in City and Highway Environments

2019 ◽  
Vol 63 (1) ◽  
pp. 1404-1408
Author(s):  
John Paul Plummer ◽  
Anastasia Diamond ◽  
Alex Chaparro ◽  
Rui Ni
Keyword(s):  
Signal Detection ◽  
Response Bias ◽  
Signal Detection Theory ◽  
Response Criterion ◽  
Crash Risk ◽  
Hazard Perception ◽  
Driving Experience ◽  
City Environment ◽  
Video Clips ◽  
The City

Hazard perception (HP) is an important aspect of driving performance and is associated with crash risk. In the current study, we investigate the effect of roadway environment (city vs. highway) and expertise on HP. HP was measured using HP clips that evaluated response lag (defined as the time from the participant’s response to the end of the clip) and fuzzy signal detection theory metrics of response criterion and sensitivity. Forty videos were used: 20 from highway environments and 20 from city environments. Forty-eight participants with a range of driving experience as assessed by the years since obtaining a license (less than 1 year to 24 years) completed the study. There were differences between city and highway environments in response lag and response bias; participants responded earlier to the hazards in the highway environment and exhibited a more liberal response bias. Driving experience was significantly correlated to response lag. When the video clips were categorized by environment, driving experience was only significantly correlated with performance for the city environment.

Loss of long-duration response to levodopa over time in PD: Implications for wearing-off

Neurology ◽  
1999 ◽  
Vol 52 (4) ◽  
pp. 763-763 ◽  
Author(s):  
M. Zappia ◽  
R. L. Oliveri ◽  
R. Montesanti ◽  
M. Rizzo ◽  
D. Bosco ◽  
...  
Keyword(s):  
Long Duration ◽  
Wearing Off ◽  
Over Time

Abstract 2645: Longer Ventricular Fibrillation Detection Duration Does Not Increase Rate of Undersensing: Results from the PREPARE Study

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Stephen Moore ◽  
Richard Stern ◽  
Mark L Brown ◽  
Brooke M Heubner ◽  
Jim W Johnson
Keyword(s):  
Primary Prevention ◽  
Ventricular Fibrillation ◽  
Shock Delivery ◽  
Long Duration ◽  
Increase Rate ◽  
The Times ◽  
Over Time

Background: The PREPARE study was designed to evaluate ICD detection and therapy parameters strategically selected to safely reduce all-cause shocks in patients with primary prevention indications by treating only truly sustained fast VT/VF. Electrophysiologic properties have been shown to deteriorate during long-duration VF episodes. There was concern that electrogram deterioration might result in increased undersensing (US) and delayed detection of VF. In this analysis we compared the rate of US between episodes detected with shorter (number of intervals to detect (NID) =12/16) and longer (NID=30/40) detection settings to assess whether delayed detection times for VF increased the rate of US. Methods: All induced VT/VF episodes from PREPARE patients programmed to NID 12/16 or 30/40 and sensitivity 1.2 mV were included in the analysis. US was determined automatically from the stored episode record. The numbers of US and the times from onset through initial detection and from detection to shock were computed. The rates of US over time were compared between the shorter and longer NIDs using a GEE analysis with time as the offset. Results: Seven hundred fifty six VF inductions in 432 patients from the PREPARE study were included in the analysis. There were 319 VF inductions (180 pts) with NID 12/16 and 437 VF inductions (261 pts) with NID 30/40. The average time from VF onset to shock increased from 6.0 to 9.5 seconds with the longer VFNID with no evidence of an increase in the rate of US over time. Conclusion: The longer NID delayed shock delivery by an average of 3.5 seconds but did not result in an increased rate of undersensing.

scholarly journals Spatial and temporal patterns of sediment storage and erosion following a wildfire and extreme flood

2019 ◽  
Vol 7 (2) ◽  
pp. 563-590 ◽  
Author(s):  
Daniel J. Brogan ◽  
Peter A. Nelson ◽  
Lee H. MacDonald
Keyword(s):  
Laser Scanning ◽  
Sediment Accumulation ◽  
Burn Severity ◽  
Spatial And Temporal Patterns ◽  
Channel Network ◽  
Erosion And Deposition ◽  
Long Duration ◽  
Extreme Flood ◽  
Changes Over Time ◽  
Over Time

Abstract. Post-wildfire landscapes are highly susceptible to rapid geomorphic changes, and the resulting downstream effects, at both the hillslope and watershed scales due to increases in hillslope runoff and erosion. Numerous studies have documented these changes at the hillslope scale, but relatively few studies have documented larger-scale post-fire geomorphic changes over time. In this study we used five airborne laser scanning (ALS) datasets collected over 4 years to quantify erosion and deposition throughout the channel network in two ∼15 km2 watersheds, Skin Gulch and Hill Gulch, in northern Colorado after a wildfire followed by a large, long-duration flood 15 months later. The objectives were to (1) quantify the volumes, spatial patterns, and temporal changes over time of erosion and deposition over a nearly 4-year period, and (2) evaluate the extent to which these spatially and temporally explicit changes are correlated to precipitation metrics, burn severity, and morphologic variables. The volumetric changes were calculated from a differencing of DEMs for 50 m long segments of the channel network and associated valley bottoms. The results showed net sediment accumulation after the wildfire in the valley bottoms of both watersheds, with greater accumulations in the wider and flatter valley bottoms in the first 2 years after burning. In contrast, the mesoscale flood caused large amounts of erosion, with higher erosion in those areas with more post-fire deposition. Only minor changes occurred over the 2 years following the mesoscale flood. Volume changes for the different time periods were weakly but significantly correlated to, in order of decreasing correlation, contributing area, channel width, percent burned at high and/or moderate severity, channel slope, confinement ratio, maximum 30 min precipitation, and total precipitation. These results suggest that morphometric characteristics, when combined with burn severity and a specified storm, can indicate the relative likelihood and locations for post-fire erosion and deposition. This information can help assess downstream risks and prioritize areas for post-fire hillslope rehabilitation treatments.

Evaluating the effectiveness of contour-felled log erosion barriers as a post-fire runoff and erosion mitigation treatment in the western United States

2008 ◽  
Vol 17 (2) ◽  
pp. 255 ◽  
Author(s):  
P. R. Robichaud ◽  
J. W. Wagenbrenner ◽  
R. E. Brown ◽  
P. M. Wohlgemuth ◽  
J. L. Beyers
Keyword(s):  
United States ◽  
Western United States ◽  
Return Periods ◽  
Rainfall Characteristics ◽  
Sediment Yields ◽  
Small Watersheds ◽  
Long Duration ◽  
Erosion Mitigation ◽  
Rain Events ◽  
Over Time

Between 1998 and 2002, six sites were established immediately after large wildfires in the western United States to determine the effectiveness of contour-felled log erosion barriers in mitigating post-wildfire runoff and erosion. In each pair of matched, burned, and small watersheds (1–13 ha), one was treated with contour-felled log erosion barriers and one was left untreated as a control. For 4 to 6 post-fire years, runoff and sediment yields were measured and correlated with rain properties. High-intensity rainfall produced most of the measured runoff and sediment yields except in the southern California site, where long-duration rain events produced most of the runoff and erosion. For small rain events (less than the 2-year return period for the 10-min duration), the runoff, peak flows, and sediment yields were lower in the treated watersheds than in the control watersheds, but there was no treatment effect for rain events with larger return periods. Improper installation and degradation over time reduced the effectiveness of contour-felled log erosion barriers. Rainfall characteristics and installation procedures should be carefully considered before choosing contour-felled log erosion barriers for post-fire hillslope stabilisation.

Motivation and the Human Monitor: I. The Effect of Contingent Credit

1969 ◽  
Vol 28 (2) ◽  
pp. 623-629 ◽  
Author(s):  
Charles G. Halcomb ◽  
Peggy Blackwell
Keyword(s):  
The Other ◽  
Group Level ◽  
Visual Monitoring ◽  
Monitoring Task ◽  
College Population ◽  
Improved Performance ◽  
High Level ◽  
Over Time ◽  
Course Credit

This research was designed to test the hypothesis that relevant incentives would result in improved performance on a visual monitoring task. Course credit was used as an incentive due to its apparent relevance for the college population. Two groups of Ss were employed. One group received credit made contingent on performance; the other group received credit for participation. The contingent group performed at a higher level than did the non-contingent group. Level of performance for both groups was high, suggesting that a relevant incentive can be effective in maintaining a high level of performance over time.

Managing uncertainty: Lessons from volcanic lava disruption of transportation infrastructure in Puna, Hawaii

2018 ◽  
Vol 16 (1) ◽  
pp. 29 ◽  
Author(s):  
Karl Kim, PhD ◽  
Pradip Pant, PhD ◽  
Eric Yamashita, MURP
Keyword(s):  
Travel Behavior ◽  
Planning Process ◽  
Critical Role ◽  
Volcanic Hazards ◽  
Problem Definition ◽  
Transportation Infrastructure ◽  
Background Information ◽  
Effective Response ◽  
Long Duration ◽  
Response And Recovery

A recent lava flow in Puna, Hawaii, threatened to close one of the major highways serving the region. This article provides background information on the volcanic hazards and describes events, responses, and challenges associated with managing a complex, long-duration disaster. In addition to the need to better understand geologic hazards and threats, there is a need for timely information and effective response and recovery of transportation infrastructure. This requires coordination and sharing of information between scientists, emergency managers, transportation planners, government agencies, and community organizations. Transportation assets play a critical role in terms of problem definition, response, and recovery. The challenges with managing a long-duration event include: (1) determining when a sufficient threat level exists to close roads; (2) identifying transportation alternatives; (3) assessing impacts on communities including the direct threats to homes, businesses, structures, and infrastructure; (4) engaging communities in planning and deliberation of choices and alternatives; and (5) managing uncertainties and different reactions to hazards, threats, and risks. The transportation planning process provides a pathway for addressing initial community concerns. Focusing not just on roadways but also on travel behavior before, during, and after disasters is a vital aspect of building resilience. The experience in Puna with the volcano crisis is relevant to other communities seeking to adapt and manage long-term threats such as climate change, sea level risk, and other long-duration events.

The Effect of Pacing and Explicit Costs on Human Decision Making Performance in Inspection

1998 ◽  
Vol 42 (16) ◽  
pp. 1175-1179 ◽  
Author(s):  
Tom McDonald ◽  
Anand K. Gramopadhye
Keyword(s):  
Decision Making ◽  
False Alarm ◽  
Signal Detection Theory ◽  
Visual Inspection ◽  
Judgment Task ◽  
Response Criterion ◽  
Critical Component ◽  
Decision Performance ◽  
Primary Determinant ◽  
Human Decision

Decision making is a critical component of visual inspection and a primary determinant of inspection quality. Previous studies in inspection have shown that pacing and costs have an effect on decision performance. The objective of this study was to evaluate human decision making performance under different conditions of pacing and cost tradeoffs. The study utilized twelve subjects who performed a decision-making (line judgment) task under paced and unpaced conditions and under various reward and penalty structures associated with various decision making outcomes (hits, correct accepts, false alarm, misses). The results were analyzed using Signal Detection Theory (SDT) measures of sensitivity and response criterion. Explicit costs had a significant effect on the response criterion, whereas pacing had a significant effect on the sensitivity.

scholarly journals Infodemic Signals Detection in the COVID-19 Pandemic: A Methodology for Identifying Potential Information Voids in Online Conversations (Preprint)

2021 ◽  
Author(s):  
Tina D Purnat ◽  
Paolo Vacca ◽  
Christine Czerniak ◽  
Sarah Ball ◽  
Stefano Burzo ◽  
...  
Keyword(s):  
Public Health ◽  
Social Media ◽  
Public Health Response ◽  
Effective Response ◽  
Aggregated Data ◽  
Health Response ◽  
Online Conversations ◽  
Social Media Platforms ◽  
Over Time ◽  
Social Listening

BACKGROUND The COVID-19 pandemic has been accompanied by an information epidemic or “infodemic”: too much information including false or misleading information in digital and physical environments during an acute public health event, which leads to confusion, risk-taking and behaviors that can harm health, and lead to mistrust in health authorities and public health response. The analytical method described is part of the WHO work to develop tools for an evidence-based response to the infodemic, enabling prioritization of health response activities. OBJECTIVE The aim of this work was to develop a practical, structured approach to identifying narratives in public online conversations on social media platforms where concerns or confusion exist or where narratives are gaining traction, and to provide actionable data to help WHO prioritize its risk communications efforts where it is most critical in addressing the COVID-19 infodemic. METHODS We developed a taxonomy to filter global COVID-19 public online conversations in social media content in English and French into five themes, with 35 sub themes. The taxonomy and its implementation were validated for retrieval precision and retrieval recall, and reviewed and adapted as the linguistic expression about the pandemic in online conversations changed over time. The aggregated data were analyzed for each sub themes by volume, velocity and the presence of questions, on a weekly basis, to detect signals of information voids where there was potential for confusion or for mis- or dis-information to thrive. A human analyst reviewed the themes for potential information voids and used quantitative data to provide context and insight on narratives, influencers and public reactions. RESULTS A COVID-19 public health social listening taxonomy was developed and applied. A weekly analysis of public online conversations since 23 March 2020 has enabled the quantification of shifts of public interest in public health-related topics concerning the pandemic and has demonstrated the frequent resumption of information voids with verified health information. This approach therefore focuses on infodemic signal detection for actionable intelligence to rapidly inform decision-making for a more effective response, including adapting risk communication. CONCLUSIONS This approach been successfully applied during the COVID-19 pandemic to identify and take action on information voids based on analysis of infodemic signals. More broadly, the results have demonstrated the importance of ongoing monitoring and analysis of public online conversations, as information voids frequently resume and narratives shift over time. The approach is already being piloted in individual countries and WHO regions to generate localized insights and actions, while a pilot of an AI social listening platform is using this taxonomy to aggregate and compare online conversations across 20 countries. Looking beyond the COVID-19 pandemic, the taxonomy and methodology have the potential to be adapted for fast deployment in future public health events.

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