The rapid growth of unmanned aircraft system (UAS) use in both the military and civil sectors has uncovered an array of challenges within the field. In terms of human factors and ergonomics, the influence of the unique physical design of the control stations used to pilot the unmanned aircraft on local muscular fatigue and discomfort are of great concern. This study was conducted to assess the influence of two display configurations, Side-by-Side (SS) and Stacked (ST), and two chairs, Ergonomic (EC) and Captain’s (CC), on mean and median power frequencies, root mean square amplitude, posture, discomfort, workload, and seat pressure. Sixteen participants [age: 24.75 ± 2.96 years; gender: 4 female/ 12 male; height: 177.56 ± 9.09 cm; weight: 81.37 ± 16.43 kg] completed four, 2-hour simulated UAS flights for all chair/display combinations. Eight participants piloted one, 6-hour simulated UAS flight in the display/chair combination which best minimized discomfort and fatigue in the two-hour flights, EC/SS. During the two-hour flights, muscle activity, discomfort, posture, workload, and seat pressure findings indicated increased muscular fatigue and discomfort over time. Generally, the EC/SS condition appeared to best mitigate muscular fatigue and postures associated with increased risk for the development of musculoskeletal disorders. Six-hour flight data failed to provide additional insights on the influence of extended duration flights on the dependent variables of this study. Finally, linear regression analysis revealed muscle activity can likely be predicted during UAS piloting tasks using the dependent variables in this study; however, the study failed to provide evidence that models built from two-hour data can accurately predict muscle activity out to six hours.

Work related musculoskeletal disorders (WMSD) remain the focus of research efforts as costs associated with these disorders range from 13 to 54 billion dollars annually. WMSDs associated with the back and neck compromise almost 27% of all reported WMSDs. Approximately 1/3 of visual display terminal (VDT) operators report back and neck pain annually (BLS, 1998). Physical risk factors of VDTs associated with low back and neck WMSDs include static work postures and workstation design. The objectives of this study were to assess the effects of monitor height, chair type and their interaction on task performance, back/neck electromyography (EMG), perceived discomfort, and number of posture shifts. Both monitor height and chair type were assessed using two levels (high and low). Participants, four male and four female college age students, performed two data entry tasks using a standard keyboard and monitor and a fully adjustable bi-level table. In addition to the experimenter defined workstation configurations, participants were allowed to adjust their workstation to their preferred settings. Analysis of variance was performed to assess differences in task performance, perceived level of discomfort, number of posture shifts, and EMG data associated with various combinations of monitor height and chair type. Correlation analysis was performed to assess the relationship between participant's perceived discomfort and measured muscle activity to help determine if these two measurements could be used interchangeably to assess workstation design. No effect of workstation configuration (monitor height/chair type) was found for the majority of dependent variables. An exception was that configuration of low monitor, high chair, and their interaction generated significantly more muscle activity for the low back. User preferred settings were not found to differ significantly from those investigated with respect to muscle activity, perceived discomfort, posture shifts, and performance. Additionally, it was found the participants chose to position the iii workstation according to guidelines suggested in the literature for reducing WMSD discomfort. Task effects were found for performance, posture shifts, and perceived level of discomfort. Higher levels of performance and posture shifts for the neck were associated with the typing task, as opposed to the math task. Higher levels of neck discomfort, posture shifts of the feet and posture shifts of the back were associated with the math task. Correlation analysis provided evidence that perceived discomfort reported by participants and muscle activity for job tasks may not be related. Observed muscle activity for the tasks investigated in this study was low and in some instances, close to resting activity. Due to low levels of EMG, participants may not have been cognizant of their back and neck muscle activity, offering an explanation for why participants experience a cumulative effect of workstation design and seated postures, but linking particular causal factors to the development of LBP and NP is difficult. The findings of this study suggest that there are no gross physical differences between the chair types or monitor heights as defined in this study. Other factors (such as user preferences, job task demands, specific chair parameters, etc.) may significantly effect chair selection. This study found that task was a significant effect for the majority of dependent variables, and therefore may need to be a major factor driving workstation design. Workstation configuration will help determine the type of static posture assumed at a workstation, but the "discomfort or number of posture shifts" associated with that workstation and posture might be more a result of the job task requirements. / Master of Science

Future manufacturing will be characterized by the complementarity between humans and automation (human-robot collaboration). This requires new methods and tools for the design and operation of optimized manufacturing workplaces in terms of ergonomics, safety, efficiency, complexity management and work satisfaction. There have been some efforts in the recent years to propose a tool for determining optimal human-automation levels for load balancing. Although the topic is quite new, it shares some similarities with some of the existing research in the area of robotic assembly line balancing. Therefore, it is crucial to review the existing literature and find the most similar models and methods to facilitate the development of new optimization models and algorithms. One of the two contributions that this thesis gives to the research world in the RALBP context is a literature review that involves high quality articles from 1993 to beginning 2018. This literature review includes visual and comprehensive tables—and a label system— where previous research patterns and trends are highlighted. Visualization of data and results obtained by assembly line optimization tools is a very important topic that has rarely been studied. Data visualization would provide a: 1. better comprehension of patterns, trends and qualitative data 2. more constructive information absorption 3. better visualization of relationships and patterns between operations, and 4. better contribution to data manipulation and interaction. The second contribution to research found in this thesis is the use of a human modelling (DHM) tool (called IPS), which is proposed as an assessment to the ergonomic risk that a robotic assembly line may involve. This kind of studies are necessary in order to reduce one of the most frequent reasons of work absence in our today society i.e. musculoskeletal disorders (MSDs). MSDs are often the result of poor work environments and they lead to reduced productivity and quality losses at companies. In view of the above, IPS was used in order to resolve the load handling problem between human and robot, depending on their skills and availability, while fulfilling essential ISO standards i.e. 15066 and 10218:1 and :2. The literature review made it possible to select highly useful documents in developing assumptions for the experiment and contributed to consider real features detected in the industry. Results show that even though IPS is not capable of calculating an entire robotic assembly with human-robot collaboration, it is able to simulate a workstation constituted of one robot and one human. Finite and assembly motions for both human and robot are expected to be implemented in future versions of the software. Finally, the main advantages of using DHM tools in assessing ergonomic risks in RALB can be extracted from the results of this thesis. This advantages include 1. ergonomic evaluation for assembly motions 2. ergonomic evaluation for a full working day (available in future version) and 3. essential ISO standard testing (available in future version).

Future manufacturing will be characterized by the complementarity between humans and automation (human-robot collaboration). This requires new methods and tools for the design and operation of optimized manufacturing workplaces in terms of ergonomics, safety, efficiency, complexity management and work satisfaction. There have been some efforts in the recent years to propose a tool for determining optimal human-automation levels for load balancing. Although the topic is quite new, it shares some similarities with some of the existing research in the area of robotic assembly line balancing. Therefore, it is crucial to review the existing literature and find the most similar models and methods to facilitate the development of new optimization models and algorithms. One of the two contributions that this thesis gives to the research world in the RALBP context is a literature review that involves high quality articles from 1993 to beginning 2018. This literature review includes visual and comprehensive tables—and a label system— where previous research patterns and trends are highlighted. Visualization of data and results obtained by assembly line optimization tools is a very important topic that has rarely been studied. Data visualization would provide a: 1. better comprehension of patterns, trends and qualitative data 2. more constructive information absorption 3. better visualization of relationships and patterns between operations, and 4. better contribution to data manipulation and interaction. The second contribution to research found in this thesis is the use of a human modelling (DHM) tool (called IPS), which is proposed as an assessment to the ergonomic risk that a robotic assembly line may involve. This kind of studies are necessary in order to reduce one of the most frequent reasons of work absence in our today society i.e. musculoskeletal disorders (MSDs). MSDs are often the result of poor work environments and they lead to reduced productivity and quality losses at companies. In view of the above, IPS was used in order to resolve the load handling problem between human and robot, depending on their skills and availability, while fulfilling essential ISO standards i.e. 15066 and 10218:1 and :2. The literature review made it possible to select highly useful documents in developing assumptions for the experiment and contributed to consider real features detected in the industry. Results show that even though IPS is not capable of calculating an entire robotic assembly with human-robot collaboration, it is able to simulate a workstation constituted of one robot and one human. Finite and assembly motions for both human and robot are expected to be implemented in future versions of the software. Finally, the main advantages of using DHM tools in assessing ergonomic risks in RALB can be extracted from the results of this thesis. This advantages include 1. ergonomic evaluation for assembly motions 2. ergonomic evaluation for a full working day (available in future version) and 3. essential ISO standard testing (available in future version).

In the fall of 1996, the Computer Science Department at Virginia Tech initiated a joint project with a local school district, to determine how ready access to networked computing in the fifth grade would affect students. Called the PCs for Families (PCF) project, its goal was to learn what could be achieved if technology access, support, and curriculum integration could be eliminated as obstacles or constraints in the classroom and at home. A technology-rich classroom was created, with the classroom teacher trained in constructivist teaching practices and technology integration by a master teacher. Network computers were found on every desktop, with scanners, digital cameras, and other technologies scattered throughout the room. A computer was sent home with each child and teacher, and as much support as necessary was provided to all program participants, including parents. As part of this research, a yearlong field experiment was undertaken to explore the effects of the PCF intervention on the third cohort of students participating in the project. Macroergonomics served as the theoretical framework for the experiment, which focused on the in-depth, systematic assessment of those quantitative changes that resulted from exposure to the PCF fifth-grade network classroom. Students participating in the field research were randomly selected from the larger pool of students eligible for the PCF project at the school. Selected students were randomly assigned to either to the PCF fifth-grade classroom or the standard fifth-grade classroom, which served as a control group. To first-time visitors walking into the PCF network classroom, the classroom bore little resemblance to its more traditional counterparts. However, the functioning of the PCF classroom was in many ways indistinguishable from that of its traditional counterparts. The yearly average for computer use in the PCF classroom was 4.275 hours, with computer use in the PCF classroom exceeding the three hours of computer laboratory time allotted to the control class only during the last 12 weeks of school. When used, the technology functioned as an electronic replacement for materials commonly found in traditional settings. Observers reported the pedagogy remained steadfastly teacher-centered and didactic. Despite limited utilization of the computer during classroom hours, analysis of individual, academic measures indicated PCF students made significantly greater gains than control students only on standardized writing tests. PCF students also performed significantly better than control students on measures related to technology skills. Boys in the PCF classroom also made greater improvements in their attitudes towards school than boys in the control classroom. At home, PCF students were found to interact with computer technology more often than their control counterparts. Despite lower overall home use, control students reported spending more time playing computer games than PCF students. Correlational analyses indicated significant linear relationships between changes in student performance, student entry characteristics, and home computer use variables. Student previous achievement was by far the strongest predictor of student SOL test performance, with computer use only linked to student standardized test performance on the writing and mathematics sections. As the number of email messages sent by the student increased, their writing performance increased with email usage accounting for almost ten percent of the total variance in the writing score. The only other computer use measure significantly associated with test performance was student self-reports of computer use, which accounted for less than four percent of the total variance in mathematics test performance. Computer use was associated more strongly with changes in student motivation. Student self-reports of home computer use accounted for fully 30 percent of the variance in changes on the school motivation survey. Analyses of data from the PCF proxy server suggest that student web browsing overshadows other home Internet activities, with email taking precedence over chat. Further, unlike chat or email, family web usage was sustained long after students left the PCF classroom. Over 68 percent of family web usage each week was attributable to student, not family, characteristics suggesting students play a large role in determining family usage. Academic information finding provides a plausible explanation for these results, with family web usage declining somewhat during summer months when students were not in school. Stability of both web and email use was relatively high among students. In keeping with critical mass theory, student email use increased when other students used email. However, social variables were not found to have a significant effect on web usage. Girls were found to make greater use of email than boys, with this research suggesting highly visual students used email more often. The field research also found a significant increase in student self-reports of musculoskeletal problems among the PCF students. A year-end examination of workstation fit found seat and monitor heights an average of two inches higher than the corresponding student dimensions. A participatory design study was used to elicit conceptions of computer workstations from PCF students, teachers, and parents. Children were interested in gaining greater control over the workstation, both in terms of individual technology and adjustability of furniture. Parents, however, focused on improving the richness of an individual student's workspace and de-emphasized collaborative work. Teacher opinions diverged more than other groups with designs strongly influenced by pedagogic beliefs. Results from the field study provide evidence that macroergonomic methodologies for analysis and design of work systems are extensible to classroom systems, and provide a systematic framework for examining issues related to the introduction of classroom computing technology. A critical element of any successful effort to integrate technology into the curriculum is access to adequate classroom technology and support; however, as this research illustrates, they are not sufficient to ensure successful integration. This research demonstrates other forces are at work, and in keeping with macroergonomic theory, key to the success of such an effort is the "fit" between the new technology and the characteristics of the classroom system, especially those of the teacher who effectively functions as the gatekeeper for the technology. / Ph. D.