Nathan Lau | Virginia Tech (original) (raw)
Papers by Nathan Lau
Proceedings of the Human Factors and Ergonomics Society Annual Meeting, Aug 31, 2023
Springer eBooks, 2022
Alarms in industrial control rooms are defined by their ability to alert an operator of abnormal ... more Alarms in industrial control rooms are defined by their ability to alert an operator of abnormal events that require prompt response. However, when vigilant, operators may anticipate upcoming alarms, rendering those alarms less informative if not a nuisance. Three gaze-based alarm acknowledgement methods were designed by estimating operator awareness based on their eye fixations on the parameter/area of interest and parameter behavior shortly before the alarm. The three designs differed in acknowledging the types of parameter behaviors, which could be: a) near the alarm threshold, b) fluctuating drastically, or c) trending towards an alarm threshold. These three parameter behaviors correlate with increased visual sampling, which suggests higher operator awareness or expectation of alarms. In a simulator study comparing the three gaze-based acknowledgement methods against no gaze acknowledgement, 24 participants completed 24 trials of alarm monitoring task while maintaining a single parameter within a predefined range. Analysis of variance revealed that usability ratings were higher for conditions with than without gaze acknowledgements, demonstrating promise for this alarm management approach.
AHFE international, 2022
Testing and evaluation of technology design for complex systems cannot readily attain conclusive ... more Testing and evaluation of technology design for complex systems cannot readily attain conclusive results. This is because skilled professionals are often not available for testing while non-professionals may not be capable of operating the actual systems or high-fidelity simulators. Thus, practitioners and applied scientists can be challenged with decisions on selecting participant groups, which can severely constrain choices in the experimental tasks. This article presents the perspective of consequential validity, highlighting that general validity or rules to participant selection probably do not exist. Most importantly, the validity of a testing method or an empirical finding critically rests on the decisions of interest that must take into account nuances or idiosyncrasies of specific situations and desired outcomes. This perspective stands in contrast to how the literature predominantly portrays validity of testing methods or empirical findings as universal rather than focusing on outcomes within the confines of the study methods. The perspective of consequential validity calls for studies on how classical metrics of reliability and validity could manifest in consequence of specific decisions informed by empirical testing.
Lecture Notes in Computer Science, 2023
Proceedings of the Human Factors and Ergonomics Society ... Annual Meeting, Sep 1, 2022
Supervisory Control and Data Acquisition (SCADA) systems are widely adopted in critical infrastru... more Supervisory Control and Data Acquisition (SCADA) systems are widely adopted in critical infrastructures and prime targets of cyberattacks. Ecological Interface Design (EID) is postulated to be an invaluable framework for supporting operators to cope with cyber intrusions, particularly zero-day attacks because prior research has demonstrated effectiveness of ecological interfaces during unanticipated events. However, a suitable research platform is absent for studying user interface in cybersecurity of SCADA systems. This paper presents a SCADA system simulation being designed and implemented for the DURESS thermohydraulic process control simulation common in EID studies. Based on the open literature and industrial standards to ensure representativeness of industrial SCADA systems, the simulation includes two programable logical controllers, seven routers, and a server in a wired communication network. These components should be sufficient to study human response to common cyberattacks on SCADA systems and support future work in prototyping and evaluating user interfaces for SCADA cybersecurity.
Proceedings of the Human Factors and Ergonomics Society ... Annual Meeting, Sep 1, 2022
Eye metrics are effective indicators of focused visual attention and perceived workload that have... more Eye metrics are effective indicators of focused visual attention and perceived workload that have been used to differentiate surgical expertise and task difficulties. However, the change in eye metrics throughout surgical training in a cohort of trainees is under-investigated. This study collected eye-tracking data from 13 medical students practicing the peg transfer task until reaching the passing criteria of the Fundamentals of Laparoscopic Surgery. Six eye metrics measuring focused visual attention and workload were computed and then used in multiple linear regression analysis to predict trial completion time. All predictors were significant in the regression model, collectively explaining 61.7% of the variance in log-transformed completion time. Fixation rates and gaze entropy were the most important metrics at revealing skill acquisition as medical students self-train on the peg-transfer task. The results on these eye metrics demonstrate potential in assessing surgeons-in-training and providing feedback to ensure surgical competency.
12th Nuclear Plant Instrumentation, Control and Human-Machine Interface Technologies (NPIC&HMIT 2021), 2021
Transactions of the American Nuclear Society - Volume 121, 2019
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
There is increasing use of Virtual Reality (VR) to train forklift truck operators but a lack of s... more There is increasing use of Virtual Reality (VR) to train forklift truck operators but a lack of sufficient understanding of how cognitive workload changes with respect to different task demands in VR-based training. In this study, 19 novice participants completed three forklift driving lessons with varying difficulty levels (low, medium, and high) using a VR simulator. To examine the effect of repeated training on cognitive workload, two sessions were repeated by participants using the same procedures. Cognitive workload was assessed with objective (electroencephalogram [EEG] activity) and subjective (NASA-TLX) measurements. EEG theta power and NASA-TLX (mental workload) scores were significantly higher for high than low difficulty levels. However, both EEG and NASA-TLX responses were reduced with repeated training in the second session. These findings highlight the effectiveness of EEG in continuous monitoring of workload variation caused by task difficulty and implementing trainin...
Engineering Psychology and Cognitive Ergonomics, 2019
Continuous, non-invasive workload indicators of operators is an essential component for dynamical... more Continuous, non-invasive workload indicators of operators is an essential component for dynamically assigning appropriate amount of tasks between automation and operators to prevent overload and out-of-the-loop problems in computer-based procedures. This article examines the monitoring task difficulty manipulated by the task type and load, and explores physiological measurements in relation to mental workload. In a within-subject design experiment, forty-five university students performed monitoring tasks in simulated nuclear power plants (NPPs) control room. The performance of monitoring tasks (accuracy), subjective mental workload (NASA Task Load Index), as well as four eye-related physiological indices were measured and analyzed. The results show that as monitoring task difficulty increased, task performance significantly decreased while NASA-TLX, number of fixations, and dwell time significantly increased. Number of fixations and dwell time could be effective, non-invasive continuous indicators of workload for enabling adaptive computerbased procedures.
Proceedings of the International Symposium on Human Factors and Ergonomics in Health Care
Intrahospital transports rely on effective transmission of information between medical staff and ... more Intrahospital transports rely on effective transmission of information between medical staff and information systems to support Distributed Situation Awareness (DSA) on patient status and transport requirements. This study presents the preliminary results a simulation model combining discrete event simulation (DES) and agent-based modeling (ABM) to quantify SA distribution and transactions for intrahospital transportation. The simulation model captured the transport requests, transport processes, and knowledge distribution and transactions between (human or machine) agents for intrahospital transports. Specifically, this paper presents the simulation results for the successful patient transport from 17 hospital inpatient units to the radiology department for (1) transport times and (2) transport cancellations. One-way t-tests did not reveal any significant differences in average transport time and number of cancelations between outputs of 100 simulation replications and historical d...
Journal of Engineering Education
Safe-D: Safety Through Disruption, Aug 1, 2019
Project Description: Advances in the development of automated vehicle technologies (AVT) have the... more Project Description: Advances in the development of automated vehicle technologies (AVT) have the potential to benefit senior drivers by reducing exposure to hazards and compensating for diminished cognitive abilities sometimes seen in this population. However, the degree to which such benefits can be realized in this vulnerable population depends largely on the facility with which these drivers adapt to these features. This study investigates the adaptation of eighteen senior drivers to vehicles equipped with Advanced Vehicle Technologies (AVT). Specifically, this research investigates the following questions: How do senior drivers' acceptance of AVT change after extended use? How do senior drivers' attitudes change over a period of exposure to a vehicle equipped with AVT? How do senior drivers perceive the safety benefits of AVT? How do senior drivers adapt to and learn to use AVT? How do senior drivers' trust and satisfaction change with accumulated usage? What do senior drivers like most and like least about AVT? Following a study intake session that included an in-depth orientation to the study vehicle and its features, participants were assigned a vehicle to drive for a six-week naturalistic driving experience. Each study vehicle was one of four unique models: 2015 Infiniti Q50 2016 Volvo XC90 2016 Mercedes E350 2017 Audi Q7 Each study vehicle was equipped with four AVTs of interest: Blind Sport Alert (BSA) Lane Alert (LA) Lane Keep Assist (LKA) Adaptive Cruise Control (ACC) Researchers measured visual field and cognitive status at intake and assessed participant attitudes and the effect of exposure on driver confidence in and satisfaction with AVT via surveys administered before and after the driving experience, brief weekly check-in surveys during the driving experience, and focus group sessions conducted after the participant returned the study vehicle. Data Scope: This study collected data from a sample of 18 senior drivers aged 70-77. In addition, researchers collected 5,286 trip files of natura [...]
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
Spatial strategies and cognitive processes have been separately found to indicate performance in ... more Spatial strategies and cognitive processes have been separately found to indicate performance in spatial problem-solving, but their relationships have not been investigated quantitatively. This study employed eye-tracking to characterize and determine the relationship of the cognitive processes and spatial strategies employed by first year engineering students with low spatial ability. Eighty-eight engineering students with low spatial ability were recruited to complete test items in the Purdue Spatial Visualization Test: Rotations (PSVT:R) and the Santa Barbara Solids Test (SBST). Eye-tracking data were collected to indicate the encoding, transformation, confirmation cognitive processes as well as whether holistic or piecemeal strategy was employed. Strategy ratio correlated with encoding fixations more than other cognitive processes. This finding suggests that encoding may be more indicative of spatial strategies being employed than the transform and confirmation processes. Pedago...
Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 2021
Context dependent gaze metrics, derived from eye movements explicitly associated with how a task ... more Context dependent gaze metrics, derived from eye movements explicitly associated with how a task is being performed, are particularly useful for formative assessment that includes feedback on specific behavioral adjustments for skill acquisitions. In laparoscopic surgery, context dependent gaze metrics are under investigated and commonly derived by either qualitatively inspecting the videos frame by frame or mapping the fixations onto a static surgical task field. This study collected eye-tracking and video data from 13 trainees practicing the peg transfer task. Machine learning algorithms in computer vision were employed to derive metrics of tool speed, fixation rate on (moving or stationary) target objects, and fixation rate on tool-object combination. Preliminary results from a clustering analysis on the measurements from 499 practice trials indicated that the metrics were able to differentiate three skill levels amongst the trainees, suggesting high sensitivity and potential of ...
Human-Computer Interaction and Cybersecurity Handbook, 2018
Proceedings of the Human Factors and Ergonomics Society Annual Meeting, Aug 31, 2023
Springer eBooks, 2022
Alarms in industrial control rooms are defined by their ability to alert an operator of abnormal ... more Alarms in industrial control rooms are defined by their ability to alert an operator of abnormal events that require prompt response. However, when vigilant, operators may anticipate upcoming alarms, rendering those alarms less informative if not a nuisance. Three gaze-based alarm acknowledgement methods were designed by estimating operator awareness based on their eye fixations on the parameter/area of interest and parameter behavior shortly before the alarm. The three designs differed in acknowledging the types of parameter behaviors, which could be: a) near the alarm threshold, b) fluctuating drastically, or c) trending towards an alarm threshold. These three parameter behaviors correlate with increased visual sampling, which suggests higher operator awareness or expectation of alarms. In a simulator study comparing the three gaze-based acknowledgement methods against no gaze acknowledgement, 24 participants completed 24 trials of alarm monitoring task while maintaining a single parameter within a predefined range. Analysis of variance revealed that usability ratings were higher for conditions with than without gaze acknowledgements, demonstrating promise for this alarm management approach.
AHFE international, 2022
Testing and evaluation of technology design for complex systems cannot readily attain conclusive ... more Testing and evaluation of technology design for complex systems cannot readily attain conclusive results. This is because skilled professionals are often not available for testing while non-professionals may not be capable of operating the actual systems or high-fidelity simulators. Thus, practitioners and applied scientists can be challenged with decisions on selecting participant groups, which can severely constrain choices in the experimental tasks. This article presents the perspective of consequential validity, highlighting that general validity or rules to participant selection probably do not exist. Most importantly, the validity of a testing method or an empirical finding critically rests on the decisions of interest that must take into account nuances or idiosyncrasies of specific situations and desired outcomes. This perspective stands in contrast to how the literature predominantly portrays validity of testing methods or empirical findings as universal rather than focusing on outcomes within the confines of the study methods. The perspective of consequential validity calls for studies on how classical metrics of reliability and validity could manifest in consequence of specific decisions informed by empirical testing.
Lecture Notes in Computer Science, 2023
Proceedings of the Human Factors and Ergonomics Society ... Annual Meeting, Sep 1, 2022
Supervisory Control and Data Acquisition (SCADA) systems are widely adopted in critical infrastru... more Supervisory Control and Data Acquisition (SCADA) systems are widely adopted in critical infrastructures and prime targets of cyberattacks. Ecological Interface Design (EID) is postulated to be an invaluable framework for supporting operators to cope with cyber intrusions, particularly zero-day attacks because prior research has demonstrated effectiveness of ecological interfaces during unanticipated events. However, a suitable research platform is absent for studying user interface in cybersecurity of SCADA systems. This paper presents a SCADA system simulation being designed and implemented for the DURESS thermohydraulic process control simulation common in EID studies. Based on the open literature and industrial standards to ensure representativeness of industrial SCADA systems, the simulation includes two programable logical controllers, seven routers, and a server in a wired communication network. These components should be sufficient to study human response to common cyberattacks on SCADA systems and support future work in prototyping and evaluating user interfaces for SCADA cybersecurity.
Proceedings of the Human Factors and Ergonomics Society ... Annual Meeting, Sep 1, 2022
Eye metrics are effective indicators of focused visual attention and perceived workload that have... more Eye metrics are effective indicators of focused visual attention and perceived workload that have been used to differentiate surgical expertise and task difficulties. However, the change in eye metrics throughout surgical training in a cohort of trainees is under-investigated. This study collected eye-tracking data from 13 medical students practicing the peg transfer task until reaching the passing criteria of the Fundamentals of Laparoscopic Surgery. Six eye metrics measuring focused visual attention and workload were computed and then used in multiple linear regression analysis to predict trial completion time. All predictors were significant in the regression model, collectively explaining 61.7% of the variance in log-transformed completion time. Fixation rates and gaze entropy were the most important metrics at revealing skill acquisition as medical students self-train on the peg-transfer task. The results on these eye metrics demonstrate potential in assessing surgeons-in-training and providing feedback to ensure surgical competency.
12th Nuclear Plant Instrumentation, Control and Human-Machine Interface Technologies (NPIC&HMIT 2021), 2021
Transactions of the American Nuclear Society - Volume 121, 2019
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
There is increasing use of Virtual Reality (VR) to train forklift truck operators but a lack of s... more There is increasing use of Virtual Reality (VR) to train forklift truck operators but a lack of sufficient understanding of how cognitive workload changes with respect to different task demands in VR-based training. In this study, 19 novice participants completed three forklift driving lessons with varying difficulty levels (low, medium, and high) using a VR simulator. To examine the effect of repeated training on cognitive workload, two sessions were repeated by participants using the same procedures. Cognitive workload was assessed with objective (electroencephalogram [EEG] activity) and subjective (NASA-TLX) measurements. EEG theta power and NASA-TLX (mental workload) scores were significantly higher for high than low difficulty levels. However, both EEG and NASA-TLX responses were reduced with repeated training in the second session. These findings highlight the effectiveness of EEG in continuous monitoring of workload variation caused by task difficulty and implementing trainin...
Engineering Psychology and Cognitive Ergonomics, 2019
Continuous, non-invasive workload indicators of operators is an essential component for dynamical... more Continuous, non-invasive workload indicators of operators is an essential component for dynamically assigning appropriate amount of tasks between automation and operators to prevent overload and out-of-the-loop problems in computer-based procedures. This article examines the monitoring task difficulty manipulated by the task type and load, and explores physiological measurements in relation to mental workload. In a within-subject design experiment, forty-five university students performed monitoring tasks in simulated nuclear power plants (NPPs) control room. The performance of monitoring tasks (accuracy), subjective mental workload (NASA Task Load Index), as well as four eye-related physiological indices were measured and analyzed. The results show that as monitoring task difficulty increased, task performance significantly decreased while NASA-TLX, number of fixations, and dwell time significantly increased. Number of fixations and dwell time could be effective, non-invasive continuous indicators of workload for enabling adaptive computerbased procedures.
Proceedings of the International Symposium on Human Factors and Ergonomics in Health Care
Intrahospital transports rely on effective transmission of information between medical staff and ... more Intrahospital transports rely on effective transmission of information between medical staff and information systems to support Distributed Situation Awareness (DSA) on patient status and transport requirements. This study presents the preliminary results a simulation model combining discrete event simulation (DES) and agent-based modeling (ABM) to quantify SA distribution and transactions for intrahospital transportation. The simulation model captured the transport requests, transport processes, and knowledge distribution and transactions between (human or machine) agents for intrahospital transports. Specifically, this paper presents the simulation results for the successful patient transport from 17 hospital inpatient units to the radiology department for (1) transport times and (2) transport cancellations. One-way t-tests did not reveal any significant differences in average transport time and number of cancelations between outputs of 100 simulation replications and historical d...
Journal of Engineering Education
Safe-D: Safety Through Disruption, Aug 1, 2019
Project Description: Advances in the development of automated vehicle technologies (AVT) have the... more Project Description: Advances in the development of automated vehicle technologies (AVT) have the potential to benefit senior drivers by reducing exposure to hazards and compensating for diminished cognitive abilities sometimes seen in this population. However, the degree to which such benefits can be realized in this vulnerable population depends largely on the facility with which these drivers adapt to these features. This study investigates the adaptation of eighteen senior drivers to vehicles equipped with Advanced Vehicle Technologies (AVT). Specifically, this research investigates the following questions: How do senior drivers' acceptance of AVT change after extended use? How do senior drivers' attitudes change over a period of exposure to a vehicle equipped with AVT? How do senior drivers perceive the safety benefits of AVT? How do senior drivers adapt to and learn to use AVT? How do senior drivers' trust and satisfaction change with accumulated usage? What do senior drivers like most and like least about AVT? Following a study intake session that included an in-depth orientation to the study vehicle and its features, participants were assigned a vehicle to drive for a six-week naturalistic driving experience. Each study vehicle was one of four unique models: 2015 Infiniti Q50 2016 Volvo XC90 2016 Mercedes E350 2017 Audi Q7 Each study vehicle was equipped with four AVTs of interest: Blind Sport Alert (BSA) Lane Alert (LA) Lane Keep Assist (LKA) Adaptive Cruise Control (ACC) Researchers measured visual field and cognitive status at intake and assessed participant attitudes and the effect of exposure on driver confidence in and satisfaction with AVT via surveys administered before and after the driving experience, brief weekly check-in surveys during the driving experience, and focus group sessions conducted after the participant returned the study vehicle. Data Scope: This study collected data from a sample of 18 senior drivers aged 70-77. In addition, researchers collected 5,286 trip files of natura [...]
Proceedings of the Human Factors and Ergonomics Society Annual Meeting
Spatial strategies and cognitive processes have been separately found to indicate performance in ... more Spatial strategies and cognitive processes have been separately found to indicate performance in spatial problem-solving, but their relationships have not been investigated quantitatively. This study employed eye-tracking to characterize and determine the relationship of the cognitive processes and spatial strategies employed by first year engineering students with low spatial ability. Eighty-eight engineering students with low spatial ability were recruited to complete test items in the Purdue Spatial Visualization Test: Rotations (PSVT:R) and the Santa Barbara Solids Test (SBST). Eye-tracking data were collected to indicate the encoding, transformation, confirmation cognitive processes as well as whether holistic or piecemeal strategy was employed. Strategy ratio correlated with encoding fixations more than other cognitive processes. This finding suggests that encoding may be more indicative of spatial strategies being employed than the transform and confirmation processes. Pedago...
Proceedings of the Human Factors and Ergonomics Society Annual Meeting, 2021
Context dependent gaze metrics, derived from eye movements explicitly associated with how a task ... more Context dependent gaze metrics, derived from eye movements explicitly associated with how a task is being performed, are particularly useful for formative assessment that includes feedback on specific behavioral adjustments for skill acquisitions. In laparoscopic surgery, context dependent gaze metrics are under investigated and commonly derived by either qualitatively inspecting the videos frame by frame or mapping the fixations onto a static surgical task field. This study collected eye-tracking and video data from 13 trainees practicing the peg transfer task. Machine learning algorithms in computer vision were employed to derive metrics of tool speed, fixation rate on (moving or stationary) target objects, and fixation rate on tool-object combination. Preliminary results from a clustering analysis on the measurements from 499 practice trials indicated that the metrics were able to differentiate three skill levels amongst the trainees, suggesting high sensitivity and potential of ...
Human-Computer Interaction and Cybersecurity Handbook, 2018
Human Factors in Practice Concepts and Applications, 2017