Iranian Journal of Ergonomics

Application of Electroencephalography (EEG) in Ergonomics: A Systematic Review

Bahram Kouhnavard

Background and Objectives: Electroencephalography is one of the non-invasive and relatively inexpensive methods that can be used to evaluate neurophysiology and cognitive functions. This systematic review study was performed with the aim of using electroencephalography (EEG) in ergonomics.
Methods: In this review study, all articles published in Persian and English on the application of electroencephalography (EEG) in ergonomics from March 20, 2010 to March 21, 2021 were reviewed. For this purpose, a systematic search of articles was performed using the keywords cognitive ergonomics, mental fatigue, electroencephalography, EEG and brain waves in the databases of PubMed, Google Scholar, Web of science, SID, Scopus, Magiran Iran Medex.
Results: Most studies were conducted between 2015 and 2020 (41 papers) and most of the subjects were car drivers. Selected articles were reviewed in seven areas of mental fatigue, mental workload, mental effort, visual fatigue, working memory load, emotions, stress, and error diagnosis. The journal Perceptual and Motor Skills, followed by Applied Ergonomics, published the largest number of related articles.
Conclusion: In the reviewed articles, the assessment of a person's mental states, especially when driving a vehicle, has been further studied and through it, tracking, monitoring and various tasks of working memory have been followed. Future research should focus on the use of computational methods that take into account the dynamic and unstable nature of EEG data. Such an approach could facilitate the development of fatigue detection systems and automated adaptive systems.

Design of A Modular, Interactive and Ergonomic Workbench and Chair for Jewelry Making

Ali Faraji

Background and Objectives: The jewelry industry accounts for a large share of the income of the people and the government. Workbench and chair are the main tool for manufacturers, designers, art students and repairmen in this field as a group of users for the efficiency of making jewelry. This research seeks to design a workbench and chair for making jewelry that, in addition to being modular, is also interactive and ergonomic.
Methods: This research is practical as well as qualitative-descriptive in nature. It has used a survey method to collect data in which its most important tools in the practical were verbal-visual (questionnaire, interview) and non-verbal (observation). Its design method was the so-call Design up (Tarrahi Nameh in Persian) which has based on interaction design and a user-centered approach. One of the most useful techniques called the hierarchical analysis process (AHP) has been employed to prioritize users and selected designs.
Results: The result of this research is a modular, interactive and ergonomic workbench and chair under the Mosavvab brand. Their users have the advantage of an independent design resulting from its modularity, benefit from usability as well as engagement user experience due to its interactivity and finally, they satisfy from its safety and comfort due to its ergonomics.
Conclusion: This achievement eliminates tangible and intangible problems and not only provides users with personal satisfaction but also reduces the need for many medical treatments. Six elements of usability such as effectiveness, efficiency, safety/comfort, utility, easy to learn and ease to memory, on the one hand, would be brought. The goals of interaction design as visibility, feedback, constraints, consistency, affordance and engaging user experience, on the other hand, would be illustrated.

Experimental Study of Exposure to Human Vibration and Its Relationship with Physical Performance in Mining Equipment Operators

Ramin Rahmani

Background: Exposure to vibration is one of the occupational agents that causes a variety of health effects. The aim of this study was to determine the association between exposure to human vibration and the physical performance of mining drivers.
Methods: In the present study, 65 drivers working in one of the Iron Ore mines, were asked to complete the standard questionnaire for assessing the level of disability of the arm, shoulder and hand (DASH). Exposure to human vibration was measured using Svantek 106 vibrometer. Drivers' physical performance was assessed based on grip strength, Pegboard dexterity, and monofilament finger sensory tests. Data were analyzed using SPSS 21 software.
Results: The average vibration acceleration whole body (WBV) and hand-arm (HAV) were 1.00±0.23 and 2.46±0.68 m/s² respectively. There was a significant relationship between exposure to HAV and grip strength and hand dexterity (p <0.05). According to the DASH score, 56.9% of drivers had mild and 43.1% had moderate upper limb disability. The results of the multiple regression model with a coefficient of determination of 0.207 showed that the WBV in the presence of other predictor variables had a significant effect on DASH score (p<0.05).
Conclusion: In mining truck drivers, WBV exposure was higher and HAV exposure was lower than the national exposure limits. The results confirmed that WBV caused by mining trucks is the most important risk factor affecting the level of drivers' disability.

Investigating the Effects of Organizational Socialization and Social Capital on the Responsibility of Nurses in Iran Hospitals: The Mediating Role of Work Ethics

mohammad razzaghi

Background and Objectives: Nurses are one of the most important forces in a hospital. Therefore, their socialization is important to act as social capital for the hospital through sociability and to increase their responsibility as well as work ethic. Therefore, the purpose of this study was to investigate the effect of organizational socialization and social capital on responsibility with the mediating role of the organizational work ethic of Nurses at Iran Hospital, Iranshahr in Sistan & Balouchestan Province, Iran.
Methods: This research is applied in terms of purpose and descriptive correlation in terms of data collection based on structural equation modeling. The statistical population included all Nurses of Iran Hospital (550 subjects). The sample size was 218 according to the statistical population and using stratified random sampling method and Krejcie & Morgan table. Standard questionnaires of organizational socialization, social capital, responsibility and work ethics were used to collect data. The collected data were analyzed using SPSS 25 and LISREL 8.8 software.
Results: There was a positive and significant relationship between organizational socialization and social capital with work ethics. Also, the correlation coefficient between the variables of work ethics and responsibility (r = 0.39) is positive and significant. At the same time, with the mediation of work ethics, the variables of organizational socialization and social capital can predict responsibility.
Conclusion: Socialization allows nurses to gain more knowledge and skills in their work. Through socialization, nurses become a social capital for the hospital, and socialization and social capital increase work ethic, which in turn increases their responsibility.

Investigating the Effect of Wearing Medical Gloves on Grip Strength and Manual Dexterity

Payam Khanlari

Background and Objectives: Hospital and medical staff use medical gloves to protect themselves and their patients from infectious agents. Wearing gloves may reduce manual dexterity and grip strength and interfere with work performance. The aim of this study was to investigate the effect of wearing medical gloves on grip strength, manual dexterity, and perceived comfort.
Methods: 20 people (10 women, 10 men) participated in this study. Participants were tested in three gloveless modes, with latex gloves and with nitrile gloves with two tests, a 9-hole pegboard and a modified pegboard. Perceived comfort in working with gloves, wearing and removing gloves was also assessed using a subjective scale.
Results: The age range of participants was 20 to 40 years with an average of 29.45 years. There was a significant difference in manual dexterity between gloveless hands and nitrile gloves in the 9-hole pegboard test. In the modified pegboard test, gloveless hand manual dexterity was significantly different from both latex and nitrile gloves. The results also showed that wearing any type of glove significantly reduced the grip strength of individuals. The worst comfort rating was given to wearing gloves.
Conclusion: The results of this study showed that wearing gloves reduces manual dexterity and grip strength. A modified pegboard test is also recommended to assess the manual dexterity of medical gloves. Latex and Nitrile gloves are difficult to wear and should be considered in designs.

Identification and Evaluation of Fault in Human-Machine Interactive System using CREAM Technique and Fault Tree Analysis

Mohammad Saidi-Mehrabad

Background and Objectives: Despite contribution to catastrophic accidents, human errors have been generally ignored in the design of human-machine (HM) systems and the determination of the level of automation (LOA). This paper aims to develop a method to estimate the level of automation in the early stage of the design phase considering both human and machine performance.
Methods: A quantitative method is used to evaluate the performance of the whole human-machine system by the human-in-the-loop fault tree analysis while a qualitative and cross-sectional method is used to estimate human errors using the CREAM technique. The data are collected from real cases that happened in the control room of the Ferdowsi power plant.
Results: Full automatic option with an average error of 0.013 had the lowest error rate, i.e. 1/8 of the error rate of the manual design. In addition, the CREAM analysis showed that the control room operators were not satisfied with the availability of procedures and Man-Machine Interface and operational support in general. Thus, on average, the reliability of the manual design is less than the reliability of the automatic setting.
Conclusion: High machine reliability has led to the fact that the fully automatic design would be one of the best design choices for human-machine systems. However, based on the previous studies, high automation may have some human-out-of-the-loop shortcomings. Thus, this study proposed solutions to overcome these disadvantages based on the importance of the control parameters or the essence of human involvement in some decision-making and execution tasks.

Conceptual Design of An Ergonomic Desk Converter Using Anthropometric Data of Iranian Community

Morteza Mahdavi

Background and Objectives: For many employees, students and “Behind the desk jobs”, most of the daily work is done while sitting on a chair and behind a desk. This happens while many studies are associating long-term sedentary posture with musculoskeletal and cardiovascular diseases, etc. The aim of the present research is to design a tool that helps to change the working posture of people who work at sedentary workstations from sitting to stand-sit posture.
Methods: The measurements needed to design a desk converter were extracted from the existing anthropometric data of the Iranian community between the ages of 6-19 and 20-60 for both sexes, using 4 anthropometric parameters of elbow (to floor) height sitting, eye height sitting, elbow height standing and eye height standing. These values were used to obtain the difference between the required work surface of the hand while sitting and standing (keyboard position) and the difference of the required work surface of the eye while sitting and standing (display position). Due to the adjustability of this tool, 5^th percentile of women and 95^th percentile of men were used to achieve the required range of changes.
Results: The desk converter constitutes two parts, 1. Top surface (meant for monitor) and 2. the keyboard tray. The difference in the height of these two surfaces was calculated 12cm. The maximum height of the desk converter (adjustable range) for both age groups was 68 cm due to changes in sitting and standing elbow height. The width and depth of the desk are set at 90 by 50 cm, and the keyboard and mouse surface, with a width equal to the desk’s and a depth of 20 cm, creates sufficient and comfortable space for users.
Conclusion: It is envisioned that by using this tool and changing the posture of individuals from an entirely sitting posture to standing and sitting alternation, a contribution to the reduction of musculoskeletal, cardiovascular, diabetes and cancer problems can be made.

Explain the Model of Optimizing the Relationship between Labor and the Industrial Environment Through Architectural Criteria

Azadeh shahcheraghi

Background and Objectives: Job satisfaction and improving employee performance due to direct relationships with individual and environmental factors is one of the most important issues in optimizing the industrial environment. Since the main lever of decreasing or increasing productivity is human resources, one of the issues that will engage the leading managers in the coming decade is trying to increase employee productivity. Regarding the disposal of some affairs to the private sector and lack of adequate health supervision, in some cases, we witness an increase in this disorder in our country. The physical environment of the built environment affects mental health directly and indirectly, meaning that the physical environment, such as the residence and workplace, is a place for human life and some of its psychological effects are unknown.
Methods: The purpose of this research is to explain the model optimization model of labor and the industrial environment through architectural standards. This research is an applied research. In this research, the opinions were gathered through interviews. Then using grounded theory and open, axial and selective coding, the model was developed. In the following, confirmatory factor analysis was used to examine the validity of the items by Lisrel software.
Results: The results showed that indices such as environmental and physical ergonomics, visual contrast of space, environmental psychology, spatial separation of space, attention to voice and color are influential.
Conclusion: Psychological comfort is an inevitable aspect of user satisfaction studies. These findings help designers, architects, planners, and facility managers to develop workplace design principles.