Multiple devices such as desktops, laptops, and cell phones are often used to manage users' personal information, such as files, calendars, contacts, emails, and bookmarks. This dissertation presents the results of two studies that examined users' mental workload in this context, especially when transitioning tasks from one device to another. In a survey of 220 knowledge workers, users reported high frustration with current devices' support for task migration, e.g. making files available on multiple machines. To investigate further, I conducted a controlled experiment with 18 participants. While they performed PIM tasks, I measured their mental workload using subjective measures and physiological measures. Some systems provide support for transitioning users' work between devices, or for using multiple devices together; I explored the impact of such support on mental workload and task performance. Participants performed three tasks (Files, Calendar, Contacts) with two treatment conditions each (lower and higher support for migrating tasks between devices.) This dissertation discusses my findings: workload measures obtained using the subjective NASA TLX scale were able to discriminate between tasks, but not between the two conditions in each task. Task-Evoked Pupillary Response, a continuous measure, was sensitive to changes within each task. For the Files task, a significant increase in workload was noted in the steps before and after task migration. Participants entered events faster into paper calendars than into an electronic calendar, though there was no observable difference in workload. For the Contacts task, task performance was equal, but mental workload was higher when no synchronization support was available between their cell phone and their laptop. Little to no correlation was observed between task performance and both workload measures, except in isolated instances. This suggests that neither task performance metrics nor workload assessments alone offer a complete picture of device usability in multi-device personal information ecosystems. Traditional usability metrics that focus on efficiency and effectiveness are necessary, but not sufficient, to evaluate such designs. Given participants' varying subjective perceptions of these systems and differences in task-evoked pupillary response, aspects of hot cognition such as emotion, pleasure, and likability show promise as important parameters in system evaluation. / Ph. D.

Workers are challenged by the increasingly complex multitasking environments they experience. To interact effectively with these environments, they must avoid overload. When workers get overloaded (when their mental demands exceed the resource capacity) quality drops, performance degrades, and safety suffers. What is largely unknown, however, is whether these results translate to postural tasks. Postural stability exhibits an entirely different set of challenges: injury, the danger of slips and falls, and risks associated with aging workers or those who have mental or physical challenges. An assembly line worker, for example, must assume different postures, interact with the product in some way, and react to visual and auditory alarms. Mistakes could be dangerous. It is clearly important, then, to understand the interactive effects of mental and postural workload. The goal of this research was to quantify the effects of mental and postural demands on overall workload. To accomplish this, we implemented three studies that were designed to capture the synergistic effects of different task types on overall workload and compare different types of workload measures against each other to help further design research in the area. We designed a dual-task mental/postural protocol to test the differential effects of a series of cognitive demands found in dual-task postural studied. The results of the first study depict a clear picture: the addition of an auditory task to unstable seating decreases postural sway. Based solely on this result, it might be concluded that workload did not increase. Using the same protocol while measuring mental workload however, we found that workload did in fact increase both subjectively and objectively, even when similar postural benefit was found. Even as performance seemed to improve, the participant moved nearer to possible overload and performance decrement (a condition we did not induce in this research). Based on the differences found between the different measures, we believe the importance of measuring overall workload as well as individual task performance in cognitive/postural dual-task research is very high. / Ph. D.

The objective of this study was to determine which size symbols should be used by the U.S. Army for an operator control unit to indicate the status of unmanned ground vehicles (UGVs). Three sizes of symbols were studied. The symbols subtended 20, 40, and 69 minutes of arc corresponding to 0.116, 0.233, and 0.400 inches high when viewed at a distance of 20 inches from a touch screen. Twelve participants were asked to watch the symbols on a map display and touch one of four UGV symbols when it stopped moving. Different numbers (0, 8 and 12) of distracter symbols with the same height as the UGV symbols appeared during the experimental trials. The time to notice that a UGV symbol had stopped (recognition time) and to touch the screen (response time) were measured. Participants were asked for Subjective Workload Assessment Technique (SWAT) ratings for each combination of symbol size and number of distracter symbols. Errors committed while attempting to touch the correct symbol were counted. Participants made very few errors attempting to touch the wrong symbol. Results for the time and error measures were as expected for changes in symbol size. As symbol size increased, recognition time, response time, and extra touches decreased. Significant differences were seen in these measures between the subtending 20 and 40 minutes of arc and between symbols subtending 20 and 69 minutes of arc. Also, as expected, subjective mental workload increased as symbol size decreased with differences seen between all symbol size levels. No significant differences were observed for workload manipulation (number of distracter symbols) as measured by time and error. However, SWAT scores did show a significant difference as a result of number of distracters. The differences between 0 and 8 distracters and between 0 and 12 distracters were significant. There was no significant interaction between symbol size and number of distracters for any of the measures. Overall results suggest that symbols smaller than those recommended for keypads may be sufficient for interactive map displays. For static platforms with barehanded operators, symbols that subtend 40 minutes of arc may be sufficiently large to ensure adequate touch screen performance under low to moderate workload conditions. / Master of Science

This thesis measured the mental workload associated with operating a voice activated software application run on wearable computer under five different communication styles (buttons, command line, icon buttons, icon text menus, and text menus). The goal of this thesis was to determine which communication style would be best allow wearable computer users to simultaneously perform other non-computer tasks. Thirty subjects were randomly assigned to using one of five software versions (n = 6), each of which utilized a unique communication style. The mental workload associated with operating each version was assessed by monitoring the performance of secondary tasks. Secondary tasks consisted of completing a block assembly, digit subtraction, and walking along a marked pathway. Each secondary task was performed twice by itself and once while operating one of the software versions, creating a total of nine trials per subject. Block assembly task performance measures included average assembly time, percentage correct blocks, and percentage correct blocks attempted. Digit subtraction measures included percentage of correct digits. And path walking measures included average walking speed. Subjective estimates of mental workload were also collected for those trials in which subjects operated the wearable computer and performed physical tasks using the NASA Task Load Index (TLX). Finally, usability information was collected for each software version via a questionnaire form. Each of the five versions of the experimental software application was operationally identical to the others, but utilized a separate communication style. The button version displayed available functions via sets of labeled buttons in the control screen. The icon button version replaced the appearance of these buttons with labeled icons. The text menu version displayed available functions textually via a pull down main menu. The icon text version displayed appended icons to the left of each main menu item. Finally, the command line version displayed no labels, buttons, menus, or icons for any functions. The experimental software was designed as a day planner/scheduling application used to set reminder dates on a calendar, edit task lists, and edit phone listings. Under the multiple resource view of mental workload, it was hypothesized that the different versions and secondary tasks would demand distinct types of mental resource and, consequently, that mental workload would be observed as lowest when the version and secondary task demanded different types of mental resources. In contrast, it was also hypothesized that mental workload would be observed as highest when the version and secondary task demanded the same type of mental resources. Although separate one way ANOVAs performed on all secondary task measures failed to indicate statistically significant differences in mental workload across the versions, secondary task performance was consistently observed as best for subjects using the icon button version. Analysis of NASA TLX subscale data indicated that the block assembly task was rated as requiring less effort and the digit task rated as requiring less mental demand when the icon button version was used. These results generally support using an icon button communication style for wearable computer software applications. Results of this study are applicable to the design of the user interface of wearable computers. These results not only report subjective and objective measures for assessing the amount of mental effort associated with operating a wearable computer and performing various physical tasks simultaneously, but also provide estimates for determining the amount of physical task performance decrement to expect when wearable computer are also operated. Such data may be used to determine human factors guidelines for matching wearable computer interfaces to physical tasks so that interference between the two is minimal. / Master of Science

Human performance modeling (HPM) is often used to investigate systems during all phases of development. HPM was used to investigate function allocation in crews for future combat vehicles. The tasks required by the operators centered around three primary functions, commanding, gunning, and driving. In initial investigations, the driver appeared to be the crew member with the highest workload. Validation of the driver workload model (DWM) is necessary for confidence in the ability of the model to predict workload. Validation would provide mathematical proof that workload of driving is high and that additional tasks impact the performance. This study consisted of two experiments. The purpose of each experiment was to measure performance and workload while driving and attending to an auditory secondary task. The first experiment was performed with a human performance model. The second experiment replicated the same conditions in a human-in-the-loop driving simulator. The results of the two experiments were then correlated to determine if the model could predict performance and workload changes. The results of the investigation indicate that there is some impact of an auditory task on driving. The model is a good predictor of mental workload changes with auditory secondary tasks. However, predictions of the impact on performance from secondary auditory tasks were not demonstrated in the simulator study. Frequency of the distraction was more influential in the changes of performance and workload than the demand of the distraction, at least under the conditions tested in this study. While the workload numbers correlate with simulator numbers, using the model would require a better understanding of what the workload changes would mean in terms of performance measures. / Master of Science

The COVID-19 pandemic and subsequent shutdown and regulations have drastically altered the world of competitive sports. The global shutdown beginning in March 2020 put a significant strain on athlete's ability to train, as many fitness centers were closed to prevent disease transmission. When it was deemed that athletic competition was safe to resume, there were still strict regulations in place to support public health efforts. This retrospective study primarily aims to evaluate the effectiveness of COVID-19 safety regulations in competitive sports. Specifically, the successfulness to correctly implement social distancing guidelines is of high interest. A secondary aim of this study is to assess changes in workload during preseason training before COVID-19, during the time of heavily enforced COVID-19 regulations, and following strict COVID-19 restrictions, as workload can be a predictor of athletic injury. Participants in this study included Virginia Tech Women's Soccer athletes and data were analyzed from the first 9 preseason training sessions during the 2019, 2020, 2021 and 2022 seasons. Data were generated from participants wearing the STATSports Apex device during training. A custom MATLAB spatiotemporal program developed by the Williams Research Group was utilized to determine player proximity. Total distance (m) and high metabolic load (HMLD) (au), and high-speed distance (HSD) (m) metrics were analyzed to understand changes in participant workload. It was found that overall the Virginia Tech Women's Soccer Team's implementation of the guidelines was effective, as there were no invasion violations during the 2020 preseason sample. / Master of Science / The COVID-19 pandemic has forever changed the world as we know it. Competitive sports are no exception. The worldwide shutdown as a result of COVID-19 made it difficult for athletes to train while in isolation, as most facilities were closed to prevent disease transmission. When sports were able to continue again, there were still barriers preventing normal practices and competition. Athletes were asked to make every effort to maintain social distancing, even during training sessions. The main purpose of this study is to evaluate how well NCAA Division 1 Women's Collegiate Soccer players maintained social distancing during preseason practices. A secondary goal of this study is to uncover changes in workload from before COVID-19 (2019), during strict COVID-19 regulations (2020), and when COVID-19 restrictions had been less enforced (2021 and 2022). The reasoning for this is that how much work an athlete does can be indicative of risk for injury. If an athlete does significantly more work than usual, there is a higher risk of injury. This study will use global positioning systems (GPS) and measures that reflect workload collected from Virginia Tech Women's Soccer players. It was found that the players remained farther apart during the 2020 season due to the emphasis on social distancing, and that the workload will show a gradual increase to prevent injury. Overall, the study found that the COVID-19 regulations were effectively implemented among the Virginia Tech Women's Soccer Team in the 2020 preseason when restrictions were the highest.

New sensor and display technologies are expected to enhance the performance of soldiers by providing them more information about the battlefield. However, there is concern that greater quantities of information and increases in mental workload might cause distraction, reduce attention to dangers in the immediate environment, and threaten soldier survival. The purpose of this laboratory investigation was to quantify the effects of increases in mental workload on one of the soldier's most basic tasks --- avoiding ground hazards while walking. The participants were 12 U.S. Army infantry soldiers. The study was conducted on a treadmill that was modified to provide the participants a view of impending ground hazards up to 5 meters forward of their walking position. The study was a 2X3 fixed factor design with two levels of terrain difficulty (No Hazards and Hazards) and three levels of mental workload (No Load, Moderate load, and High load), all as within-subject effects. Mental workload was increased from the "No Load" to a "Moderate" level by requiring the participants to perform a mental arithmetic task while walking. Mental workload was increased from the "Moderate" to the "High" level of load by increasing the difficulty of arithmetic problems. The dependent variables included time and error in the performance of the mental arithmetic task, the mean and standard deviation in step length and step rate, the number of ground hazards contacted, and subjective ratings of workload. The participants" scores on the Armed Forces Qualification Test (AFQT) and subtests of the Armed Services Vocational Aptitude Battery (ASVAB) related to arithmetic skills were also obtained. The results of the investigation indicated that when the participants were required to avoid hazards, step length decreased and step rate increased, as was expected. Both measures of gait increased in variability. Subjective ratings of physical demand and effort obtained across the three levels of mental workload increased significantly, along with perceptions of workload associated with a perceived decline in performance. Subjective ratings obtained across the two levels of terrain difficulty indicated that ratings of mental demand and effort increased with each increase in level of mental workload. When the participants were confronted with the more difficult arithmetic problems at the "High" level of mental workload, time and error in performing the mental arithmetic task increased as did ratings of temporal demand, frustration, and workload attributable to a perceived decline in performance; however, subjective ratings of physical demand decreased. Interactions found between terrain difficulty and mental workload indicated that differences in ratings of performance and overall workload scores between the two levels of terrain difficulty decreased significantly between the "No Load" and the "Moderate" level of mental workload, and converged at the "High" level of mental load. Although relationships were found between perceived workload, gait, and performance of the mental arithmetic and hazard avoidance tasks, the analysis did not reveal a significant effect of mental workload on the number of hazards contacted. Some participants tended to contact more hazards at the "High" level of mental workload than at the "No Load" or the "Moderate" levels, as expected. However, other participants tended to contact more hazards at the "Moderate" level of mental load than at either of the two extremes. Still other participants tended to contact more hazards at the "No Load" level of mental workload than at the "Moderate" or the "High" levels. Correlations were found between subjective ratings of workload, mental arithmetic performance, and scores on the AFQT and subtests of the ASVAB related to arithmetic skills, but no relationships were found between test scores and performance of the hazard avoidance task. However, when test scores were used as covariates in the analysis of mental arithmetic performance, the findings revealed that the number of correct responses to the arithmetic problems decreased when the participants were required to avoid hazards. The results of the study may support the belief that the allocation of limited resources will vary based on past experience and other individual differences, and that the amount of resources allocated to a task may be influenced by the difficulty of the task, criteria for performance, and the motivation of the individual. / Master of Science

Yes / This article reviews studies conducted “in the wild” that explore the “ironies of automation” in Robotic Assisted Surgery (RAS). Workload may be reduced for the surgeon, but increased for other team members, with postural stress relocated rather than reduced, and the introduction of a range of new challenges, for example, in the need to control multiple arms, with multiple instruments; and the increased demands of being physically separated from the team. Workflow disruptions were not compared with other surgeries; however, the prevalence of equipment and training disruptions differs from other types of surgeries. A consistent observation is that communication and coordination problems are relatively frequent, suggesting that the surgical team may need to be trained to use specific verbal and non-verbal cues during surgery. RAS also changes the necessary size of the operating room instrument cleaning processes. These studies demonstrate the value of clinically-based human factors engineers working alongside surgical teams to improve the delivery of RAS. / National Institute for Health Research (NIHR) Health Services and Delivery Research (HS&DR) Programme (project number 12/5005/04). We acknowledge the support of the NIHR Clinical Research Network. The research by Hallbeck and colleagues made possible in part by the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery. The research of Weigl and colleagues was supported by the Munich Centre for Health Sciences (MC-Health). The research by Bisantz and colleagues was supported by the University at Buffalo, the ATLAS lab, and the Roswell Park Alliance Foundation. The research by Anger and Catchpole was funded by National Institute of Biomedical Imaging & Biomedical Engineering Award R03EB017447 (Catchpole/Anger) and the UCLA Medical Student Training in Aging Research Program-the National Institute on Aging (T35AG026736), the John A. Hartford Foundation, and the Lillian R. Gleitsman Foundation.

Adekvata resurser i form av optimalt antal patienter per sjuksköterska som fångar både vård och icke-patientvårdsrelaterad omvårdnad är ett problem för sjuksköterskorna världen över. Vårdtyngdsmätning kan vara ett led i att synliggöra omvårdnadsinsatserna för att säkerställa patientsäkerheten. Ett väl innehållsvaliderat vårdtyngdsinstrument inom postoperativ vård saknades. Rätt använt kan vårdtyngdsinstrument leda till positiv effekt för patienter och personal. Vårdinsatserna blir mätbara och ökar personalens medvetenhet i vårdarbetet. Studiens syfte var att innehållsvalidera och utveckla ett vårdtyngdsinstrument som används inom postoperativ vård vid Karolinska Universitetssjukhuset i Stockholm (VPV). Innehållsvalideringen utfördes med hjälp av Delfimetoden där specialistsjuksköterskor inom postoperativ vård från nio sjukhus (n=16) ingick i en expertgrupp som via enkätfrågor gav sina synpunkter på vårdtyngdsinstrumentet. Svaren bearbetades av magisterstudenterna tillsammans med handledarna till konsensus uppnåddes och ett validerat vårdtyngds-instrument VPV 2015 utformades. Studien har potential för stor klinisk betydelse och resultaten kan omsättas i det dagliga postoperativa omvårdnadsarbetet, då det är viktigt att de postoperativa patienterna får den omvårdnad de är i behov av och att vårdpersonalen kan utföra behövande omvårdnadshandlingar. / Adequate resources in terms of optimal patient distribution by a nurse who captures both health care and non- patient nursing care is a problem for nurses worldwide. Measurement workload can be a part of the visibility nursing efforts to ensure patient safety. A well content validated workload instrument in postoperative care was missing. Properly used, workload instrument can lead to positive effects for patients and staff. Care efforts are measurable and increase staff awareness in nursing work. The study's purpose was to content validity and develop a workload instrument used in post-operative care at Karolinska University Hospital in Stockholm (VPV). Content validation was performed by using the Delphi method where specialist nurses in postoperative care from nine hospitals (n = 16) were part of a group of experts through questionnaires gave their views on the workload instrument. The answers were processed by the students together with supervisors to the consensus achieved and a validated burden of workload instrument VPV 2015 designed. It is important for postoperative patients to receive appropriate levels of nursing care, and that this can be performed adequately. The study is therefore potentially of great clinical importance, and the results can be translatable into daily postoperative nursing work.

by Lam Miu-ling, Theresa. / Thesis (M.A.Ed.)--Chinese University of Hong Kong, 1991. / Bibliography: leaves 95-110. / ACKNOWLEDGEMENTS --- p.i / ABSTRACT --- p.iii / LIST OF TABLES --- p.vii / LIST OF FIGURES --- p.ix / CHAPTER / Chapter I. --- INTRODUCTION --- p.1 / Nature of the problem --- p.1 / Purpose of the study --- p.6 / Significance of the study --- p.7 / Chapter II. --- REVIEW OF LITERATURE --- p.9 / Job stress --- p.9 / Theory of P-E fit --- p.14 / Individual needs --- p.17 / Job demands --- p.20 / Job future ambiguity --- p.22 / Stress and strain --- p.27 / Social support --- p.30 / Chapter III. --- FRAMEWORK OF STUDY --- p.39 / Chapter IV. --- METHODOLOGY --- p.44 / Statement of hypotheses --- p.44 / Instrumentation --- p.45 / Definition of variables --- p.52 / Sampling design --- p.53 / Research procedures --- p.54 / Statistical procedures --- p.55 / Limitations --- p.57 / Chapter V. --- RESULTS --- p.59 / Results of pilot study --- p.59 / Results of main study --- p.60 / Reliability of instruments --- p.60 / Factor analysis of strain measures --- p.61 / Descriptive statistics of variables --- p.62 / Statistical analysis --- p.67 / Chapter VI. --- DISCUSSION OF FINDINGS --- p.79 / Teacher background characteristics and job strain --- p.79 / Job stress and job strain --- p.81 / Social support and job stress --- p.83 / Social support and job strain --- p.85 / Buffering effects of social support --- p.86 / Chapter VII. --- CONCLUSIONS AND RECOMMENDATIONS --- p.88 / Conclusions --- p.88 / Recommendations --- p.89 / Recommendations for school authority --- p.90 / Recommendations for teachers organizations --- p.91 / Recommendations for the Education Department --- p.92 / Recommendations for future research --- p.92 / REFERENCES --- p.95 / APPENDIX