Iranian Journal of Ergonomics
Year:2022 | Volume:10 | Issue:1|Papers Count:8

Dear Editor, People behave and perform differently in different situations. In addition to personality traits and knowledge and experience of people, another factor called the effect of the situation, such as the presence of others, affects people's behavior. This can direct a person's behavior in such a way that some circumstantial pressures may be so intense that they cause people to act in an unpredictable way. For example, athletes can set a better record when competing with each other than when competing alone [1]. Researchers in the past have studied the effect of others 'presence on people's behavior and performance such that Bond and Titus [2] in a meta-analysis study summarize the effect of others' presence as follows: A) the presence of others only increases a person's physiological arousal if the person is doing a complex task, B) the presence of others speeds up simple tasks and slows down complex tasks, C) the presence of others impairs the accuracy of complex performance and slightly facilitates the accuracy of simple performance, and D) the effects of social facilitation are surprisingly unrelated to the fear of evaluating the performer. The effect of attention can explain the effect of the presence of others on the behavior and performance of individuals. According to this view, the presence of others often causes distraction, and can create too much mental workload, which leads to limited concentration of attention. This perspective can also explain the different effects of having others present for simple and complex tasks: That is, when tasks are simple and need to focus on a small number of stimuli, the presence of others improves performance, and when tasks are complex and require more attention, the presence of others will have a negative impact on performance. Another study that explores more aspects of the impact of others' presence on people's performance was conducted by Huguet, Galvaing [3]. The results of the study showed that people perform better in the Stroop task (which is a complex task) in the presence of others. Also, the mere presence of another person cannot have much effect on a person's performance. On the other hand, competition and social comparison with competitors is very effective. In addition to the presence of real people, virtual humans also affect the behavior and performance of people. In the case of easy tasks, performance in virtual human conditions is better than when alone, and for difficult tasks, performance in virtual human conditions is worse than when alone. The presence of others has different effects on human behavior and performance, and most of the activities that people do are either in the community, at work, or at home. There are other people in all of these environments, but most ergonomics and human factors research does not take into account the presence of others. Research conducted in simulation laboratories to study human function and behavior tests individuals alone. Even most of the research done in the field still examines a person's performance alone and without taking in to account the impact of the presence of others. For example, research to check the performance and error of drivers in car simulations or even in a real car, regardless of the passenger, while in the real world, most cars have passengers other than the driver [4]. This is the case in most ergonomic and human research. So far, however, efforts have been made to examine human performance and behavior in teams and groups [5]. But that alone is not enough because people on teams already know each other, and research has shown that people perform differently in the presence of strangers and acquaintances. Also, people outside or even inside groups and teams may be in different situations that have to perform tasks in the presence of strangers. For example, a firefighter in a state of emergency and while a large crowd is watching him may perform differently from a situation without observers. The impact of the presence of others on the behavior and performance of individuals when interacting with complex sociotechnical systems is also unknown. By considering the presence of others in ergonomic and human factor research, real conditions for one's performance and behavior can be created and more reliable results can be achieved. Many questions now arise in this regard: such as the effect of the presence of others on the workload and mental and physical fatigue of people? Does the presence of others reduce or increase human error? How will people perform in real life and under the influence of others? These are questions that we hope researchers will pay attention to, and that ergonomic and human factor research will be done with the presence of others in mind. Because many human actions are performed in the presence of others and not alone. In short, people's behavior and performance are influenced by the presence of others and different situations. Although research has been done on the study of human factors in teams and groups, but individuals outside groups and teams or even within teams may have different actions and behaviors under the influence of the presence of others. To examine the behavior and performance of individuals more closely, ergonomics and human factors researchers should not ignore the role of others presence on human functionality in future research.

Objectives: Given the benefits of controlling Body mass index (BMI) on the quality of life, BMI classification based on facial features can be used for developing telemedicine systems and eliminate the limitations of existing measuring tools especially for paralyzed people, that enable physicians to help people online when faced with situations like the COVID-19 pandemic. Methods: In this study, new features and some previous-work features were extracted from face photos of white, black and Asian people, ages 18 to 81, with normal and overweight BMI. Faces were evaluated in three different steps. First, all faces were considered as one group. Second, they were divided into elliptical, round and square shape groups and third, they were separated based on gender. Then for each step, the performances of Random Forest (RF) and Support Vector Machine (SVM) were evaluated with all of the facial features and with selected features based on Pearson correlation coefficient. Matlab R2015b was used for implementation. Results: The results revealed that features with higher correlation improved the accuracy of both algorithms. RF best performance using highly correlated features for 97 women and 92 men was in women and square-face groups (91. 75% and 87. 30% respectively), and SVM best performance was in women group (94. 84%), square-face and round-face groups (84. 12% and 84% respectively). Conclusion: Accuracy of BMI classification based on facial features can be improved by categorizing faces into shapes and gender, and selecting appropriate features. The findings can be used for performance enhancement of telemedicine applications, especially for helping the differently-abled.

Objectives: Ankle sprain leads to a decrease in proprioception and awareness of the sense of motion with motor consequences. On the other hand, damage to this joint is an important factor in affecting balance and consequently re-injury. Strengthening the factors that help maintain balance and posture, can be a basic strategy in the treatment of balance and postural problems, as well as injuries. Methods: In this quasi-experimental study, 30 patients with chronic ankle instability were randomly divided into experimental and control groups. Both groups were pretested and the experimental group performed core stability exercises against gravity for six weeks. Post-test was taken again from both groups. Data were analyzed using oneway analysis of covariance. Statistical operations were performed at a significant level of α,≤,0. 05. Results: Postural control index in the experimental group was higher in the first position and lower than the other in the sixth position. The mean of the postural control index in the experimental group was significant compared to the control group (α,≤,0. 05). Conclusion: Performing exercises for core stability or training on unstable surfaces deploying sensory receptors is likely to cause the muscles to be more actively involved and the central nervous system to receive more appropriate and effective stimuli from the nerves of different sensory receptors, and thus this exercises improve postural stability.

Objectives: The comfort questionnaire for hand tools (CQH) is a subjective measure for exploring the starting points for improving hand tool design. This study aimed to investigate the psychometric properties of the Farsi version of the CQH. Methods: In this cross-sectional study, which was conducted among 163 university students, the 17-question CQH was translated into Farsi with a translation backtranslation procedure. Content validity was assessed by a panel of 10 experts. Exploratory Factor Analysis (EFA) was applied for determining construct validity. Cronbach’, s alpha and Intraclass Correlation Coefficient (ICC) were used for assessing internal consistency and test-retest reliability, respectively. Ceiling and floor effects were also estimated for evaluating the feasibility of the measure. Results: The CQH showed good content validity. Content validity index (CVI) ranged from 0. 80 to 1. 00 and Content Validity Ratio (CVR) ranged 0. 62-1. 00. EFA led to extraction of two factors from the data. The first one was mostly related to functionality and physical interaction and the second one, was generally about adverse body effects. The Cronbach’, s alpha was 0. 74 and test-retest reliability was 0. 74 (95% CI = 0. 58 to 0. 86) which both were satisfactory. There were no (0%) ceiling and floor effects. Conclusion: The Farsi version of CQH is an acceptable and useful instrument for evaluating hand tools comfort.

Objectives: Considering the importance of employees' behavior in service organizations and its significant impact on their success and failure, the present study investigates the environmental and ergonomic factors affecting the mental health and behavior of employees in one of the branches of Islamic Azad University. Methods: The present study is applied in terms of purpose and descriptive-correlational in terms of data gathering and analysis. The statistical population of the study includes: 315 employees of Rasht Branch of Azad University, out of them 196 people were selected by random sampling method and the necessary data were collected using a questionnaire. Structural equation modeling and SMART PLS3 software were used to test the hypotheses. Results: According to the findings, workplace layout affects on use of work equipment (0. 389), use of office chair (0. 252) and environmental conditions (0. 538), but the effect of workplace layout on the posture of employees was not confirmed in 5 percent significance level. Also, the effect of posture (0. 586), layout (0. 440), work equipment (0. 458), office chair (0. 345) and environmental conditions (0. 550) on public health and also the effect of general health (0. 690) and environmental conditions (0. 158) on employees’,behavior is significant. Examining the indirect relationships of the research model also shows that workplace layout affects employee behavior through the general health and environmental conditions. Workplace layout influences employees’,behavior through work equipment, office chair, environment conditions and general health. Conclusion: The indirect effect of workplace layout on employees’,behavior through public health has the highest impact (0. 304), therefore, making policies for the general health, can improve employees’,behavior.

Objectives: Today, many hardware and software products, including office automation software, and web-based websites are used by employees, including professors and employees of different departments in offices. Websites are considered one of the main competitive advantages in any organization. This study aims to investigate the usability of the Integrated Research Automation System (SYAT): A Heuristic Evaluation. Methods: The present study was a descriptive-cross-sectional study with a heuristic evaluation performed on the integrated research system software (SYAT) by 3 evaluators. They then evaluated the intensity of each of the ten options and scored from 0 to 4. After each problem was classified as one of the 10 branches of Nielsen's evaluation by the evaluators, similar problems were eliminated and the average scores and the severity of the deterioration of the problems were calculated. Results: A total of 92 usability problems were identified in evaluating the usability of the web-based software (system) using the components provided by Nielsen. The majority of the issues were related to the detection instead of reminder with 16 problems (17. 32%). The lowest number of problems was related to both compatibilities between the system and the real world, and the clarity of the system status with 6 cases (6. 52%). Conclusion: The usability assessment method is inexpensive and simple and the problems caused by websites and applications can be evaluated as feedback to improve them. The more accurate the needs of SYAT system users are, the more effective the system will be and the more satisfied the users will be.

Objectives: Work-induced musculoskeletal pain disorders are among the most common problems among workers. This study aimed to compare fatigue and trunk and neck postures during work in tailors with and without nonspecific chronic neck pain. Methods: In this cross-sectional study, 30 sewing machine operators participated voluntarily and were divided in two groups of people with (15 persons) and without (15 persons) chronic nonspecific neck pain. The craniovertebral, cranial, and shoulder angles were calculated three intervals (at the start of work, after 2 hours of continuous work, after 4 hours of continuous work) using the photogrammetric method. Borg scale was used to examine work-induced fatigue. A one-way repeated measure analysis of variance at the significance level of 0. 05 was used for data analysis. Results: There were significant differences in craniovertebral, cranial, and shoulder angle changes (P < 0. 001) between the two groups while working. Postural trunk and neck changes were more evident in the nonspecific chronic neck pain group. However, there were no significant differences in terms of fatigue levels between the two groups (P = 0. 639). Conclusion: The upper trunk related posture among workers with nonspecific chronic neck pain may be more negatively affected during work. So it is suggested that maintaining proper posture should be more emphasized among these workers.

Objectives: Nurses are at the front line of treatment and coping with COVID-19 pandemic. Therefore, the present study investigates the pandemic’, s impact on nurses ’, mental workload and determines its predictive factors. Methods: This descriptive-analytical study was done on 234 nurses in two groups working at COVID-19 and non-COVID-19 wards in 2020. The criteria for entering the study were the absence of psychological problems. Data was gathered using the General Health Questionnaire, NASA-TLX, and Demographic Questionnaire. Results: The mean of the overall mental workload score in the group of nurses working at the Covid-19 wards (70. 09 ±,2. 51) was higher than the group of nurses working in the non-COVID-19 wards (66. 55 ±,2. 02). This difference was significant (P = 0. 01). There was a significant difference between the mean score of the mental demand, the physical demand, the temporal demand, and the frustration level of the two groups. With the exception of performance, the group of nurses working in the corona ward had a higher mean score in all aspects. In the proposed linear model, 16% of the overall changes in mental workload depended on two variables, which were age and work experience. The work experience was the most influential factor in predicting nurses' mental workload. Conclusion: The findings of the present study showed the importance of paying attention to the mental workload of nurses as well as personal and occupational factors affecting mental workload in the conditions of the COVID-19 pandemic. Therefore, control and management of effective factors can help reduce mental workload, especially during pandemic conditions.