International Journal of Human Factors and Ergonomics (8 papers in press)
Estimation of air traffic controllers fatigue based on the analysis of the human voices fundamental frequency
by José J. Cañas, Enrique Muñoz-de-Escalona, Patricia López De Frutos, Rubén Rodríguez, Fernando Celorrio
Abstract: Any air traffic management (ATM) safety management system needs to provide measures to prevent controllers fatigue. In order to do this, it is necessary that reliable and valid procedures are in place to assess the fatigue endured by a controller in real-time. For this reason, intensive research is being carried out to develop procedures to assess controllers fatigue. The procedures that are offering the most promising results are those based on the recording of psychophysiological parameters. However, most of these procedures require expensive recording equipment and they might interfere with the control task. For this reason, it is necessary to find a procedure that has not those limitations. In this paper, a procedure based on the analysis of the fundamental frequency of the controllers voice from real operational recordings of controller-pilot radiofrequency communications is presented.
Keywords: component; mental fatigue; air traffic controller; ATC; voice fundamental frequency.
Ergonomic assessment of repetitive work time as a key parameter for job rotation schedules
by Luis A. Saavedra-Robinson
Abstract: Repetitive work, awkward postures, and load handling, along with their associated efforts, constitute one of the main causes of occupational diseases in the agricultural industry. The purpose was to design a job rotation schedule that considers the ergonomic risk and production demands that are proper for the rose harvesting tasks. The ergonomic risk was assessed through the OCRA index, which was used as a task assignment parameter. Through a case study carried out in the Colombian flower industry, respective OCRA index values for the right (3.3) and left (2.5) upper limbs in the rose harvest activities. In this case, a network-structure-based Task Programming model was introduced as the basis for the solution. The objective function (OF) yielded a feasible solution value Z = 20.1. This indicates a decreased effort resulting from the task allocation flow, which preserves the productivity of the tasks of the harvest area of the six companies under study
Keywords: scheduling job; rotation; ergonomics; risk assessment; OCRA index.
Investigating effects of adjustability features in the design of forklift backrests: a pilot study
by Pranav Madhav Kuber, Ehsan Rashedi
Abstract: This study assessed the effectiveness of an adjustable backrest towards facilitating comfort to a range of users body sizes. 12 participants were recruited in a comparative study to detect the effect of body size (5, 5-95, 95 percentile), sex, backrest type (adjustable, original), and leaning duration on comfort and stability. Body movements related to the perceived discomfort were used to quantify the convenience of individuals while leaning on the backrest. Results showed a decrease in the centre of pressure deviation by 12% for the adjustable backrest, compared to a 47% increase for the original design. Moreover, upper-body movement reduction (~20%, p-value = 0.04) denoted that adjustable backrest was more effective over longer durations. The identified improvement regions on the new backrest included backrest curvature, hook feature, and symmetric material placement. This article presents a comprehensive method for evaluating backrests, which could also be implemented for assessing similar seating products with adjustability features.
Keywords: product design; seat; industrial vehicle; motion analysis; leaning posture; adjustability; backrest; forklift; comfort; stability.
Recurrence quantification analysis to assess structure of breast motion variability for jumping jacks exercise
by Joseph E. Langenderfer, Ksenia I. Ustinova
Abstract: Prior observations and qualitative descriptions of breast motion suggest that structure of motion variability may be important for understanding how breasts move and how support from bras alters breast and body motion. The purpose of this study was to demonstrate the feasibility of utilising recurrence quantification analysis (RQA) to measure nonlinear properties of breast, thorax and upper-arm motion variability for different breast support levels and breast sizes. Support from bras causes breast motion which is less deterministic and therefore less predictable. Motion of larger breasts is less random and more complex, but these nonlinear aspects of motion, unlike amplitude, are not as dependent on size. These findings increase understanding of the structure of breast and body motion variability and how bras influence the motions. Such information may improve bra design with the goal of allowing more effective human performance of work and exercise.
Keywords: recurrence quantification analysis; RQA; brassiere; nonlinear; upper extremity.
The multifactorial causes of caregiver work-related disabilities: a systematic literature review
by Abdulelah M. Ali, Mohd Mukhtar Alam
Abstract: The purpose of this review is to discuss multifactorial causes of caregiver work-related disability. A systematised literature search was accomplished from numerous sources viz., PubMed, MEDLINE, CINAHL, and EMBASE to identify relevant studies published from 2002 to 2020. The studies were included based on a relevance and bibliographic search rating. In this review: 1) caregiver was involved in physically demanding work leading to MSD (comprising specific and non-specific musculoskeletal pain and discomfort); 2) intervention was commenced and/or performed at workstations; 3) comparison groups were included; 4) MSD measurements were reported (musculoskeletal discomfort, symptoms, prevalence or pain). This review confirmed that caregivers were susceptible to WMSD, especially back pain and injuries. Risk factors predisposing to low back pain and injury are inadequate patient transfer skills, high physical demands, inadequate conditioning of caregivers, and obesity. Therefore, essential training in work-related accident, prevention policies and ergonomics will assist caregivers.
Keywords: musculoskeletal disorders; MSDs; risk factors; patient handling; safety handling program; ergonomics and human factors.
A data-driven approach to assessing and analysing contributing factors to the severity of road accident injuries based on decision-making styles
by Ali Ghazizadeh, Mahdi Hamid, Zahra Mehdizadeh Somarin, Behnaz Salimi
Abstract: Road accidents are among the important challenges that all communities face. Fatal road accidents are closely related to the severity of the collision, which is affected by a variety of factors, including human error, road conditions and weather conditions. Individual errors are a significant cause of accidents, which are influenced by an individual's behavioural characteristics. Behavioural factors are developed by an individual's decision-making style. One of the innovative aspects of this study is the inclusion of drivers' decision-making styles in analysing the causes of accidents with severe injuries. Additionally, this study will determine the primary factors that contribute to the severity of injury utilising principal factor analysis and correlation matrix approaches. Our results show that flexible and hierarchical decision-making styles are the dominant styles in all groups. Non-observance of safe distance, vehicle defects, and bad weather are the three foremost factors affecting the severity of injuries. Human factors with nearly 60% importance, is the most important group of features in determining injury severity. Furthermore, the features of not wearing a seat belt, using a mobile phone while driving, and not observing a safe distance have the most positive alignment with injury, respectively.
Keywords: road accident; decision-making style; injury severity; principal component analysis; PCA; correlation matrix.
Posture evaluation for the full-body dynamic simulation in JACK Siemens PLM
by Xiaoxu Ji, Saeed Tiari
Abstract: The objective of this study is to evaluate the accuracy of predicted postures in JACK Siemens software via comparing with the actual human movement recorded by the Xsens motion tracking system. Seventeen student volunteers were recruited in this study and required to perform a common lift task with different loads. Our statistical results revealed the significant difference of joint angular displacements (e.g., trunk, hips, elbows, knees, and shoulders) between the simulated human movements and actual measurements. Additionally, we estimated the spinal forces imposed on the lower back of participants, which were highly correlated to the joint poses. To provide robust ergonomics analysis, the manufacturers need to continue the efforts to improve their software by reconsidering the significant individual factors, such as the muscle strength between males and females, and the effect of loads on the adopted postures during task performance.
Keywords: musculoskeletal disorder; ergonomics; digital human model; full-body dynamic simulation; posture; prediction; spinal force; JACK Siemens PLM; TSB; Xsens.
Impacts of quality management systems on occupational safety and health in industrial laboratories
by Rawan A. Al-Maaitah, Salah H. Aljbour
Abstract: The study aimed to identify the impact of adopting quality management systems on occupational safety and health (OSH) in industrial laboratories. A questionnaire was developed to study the impacts of five soft total quality management (TQM) dimensions on OSH. These dimensions are recognition, training, teamwork, leadership and ethics. The collected data were analysed by using descriptive statistical analysis, multiple regression analysis and analysis of variance. The study revealed that the five TQM variables proposed in this study have an overall impact on the status of OSH from the view point of respondents working in accredited and unaccredited laboratories. The study revealed that leadership and training ranked among the most important variables that affect the status of OSH from the view point of respondents working in accredited laboratories. Ethics is the only important variable that affects the status of OSH from the view point of respondents working in unaccredited laboratories.
Keywords: quality; soft TQM; safety; occupational safety and health; OSH; industrial laboratories; engineering; management; Jordan.