International Journal of Human Factors and Ergonomics (9 papers in press)
Assessment of Low Cost Tool Intervention among Carpet Alignment Workers Exposed to Hand-Arm Vibration and Shift in Hearing Threshold
by Ashish Kumar Singh, Makkhan Lal Meena, Himanshu Chaudhary
Abstract: Background: Before any repairing work is done on the carpet, its alignment is essential to be carried out.rnObjective: The aim of the study was to determine and assess the hand arm vibration (HAV), noise exposure, and loss in hearing threshold due to the hand tools used in carpet alignment. The effect of new handles on the transmissibility of HAV was tested. rnMethods: The data about HAV and noise level were collected from ten experienced male subjects. A case-control study was conducted to compare the hearing threshold and hand grip effort among the workers with a control group. The usability of the prototype handles was evaluated using the system usability scale (SUS). We used interviews, questionnaires, Strain Index (SI) score sheets, Borg scale, photography, and videos to analyze the perceptual effort and postural risks. rnResults: The estimate of daily vibration exposure, A(8) for prototypes tools for both the hands indicated reduction by over 26% when compared to the conventional tools. Mean equivalent sound pressure level (Leq) was quiet high (97.62dB), exceeding the exposure limit of 90dB (A). In agreement with dose consumed, exposed workers exhibits mild to moderate hearing impairment in the frequency range of 1500-6000 Hz with the loss in grip strength. SI score revealed that the intensity of exertion and the current working posture requires urgent action.rnConclusion: As the main outcomes, a low cost intervention was found effective in curtailing HAV during the field testing. The noise level while working with conventional tools was observed above risk levels when compared with IS 7194:1994 standards. The other contribution of the study is to suggest that the implementation of hearing conservation programmes and practice of personal protective equipments could prevail over hearing impairment among workers.
Keywords: Carpet alignment; Hand Arm Vibration (HAV); Noise exposure; Hearing threshold; Strain Index (SI); hand tool intervention; ergonomics; low frequency vibrations; non-powered hand tools.
Safety Index: A systematic approach to measure the level of occupational safety in manufacturing industry
by Lakhwinder Pal Singh, Satnam Singh
Abstract: Despite the advancement in technology, workplace safety in the industry still needs a significant attention. The objective of this study is to develop a new safety index, termed as OSEA index (Occupational Safety Evaluation Approach). Delphi method is used to devise the index which can be used to measure the level of occupational safety of workers in medium-sized iron and steel manufacturing industry of Punjab. This approach considered 40 factors that were validated with content validity index (CVI). The ideal value of OSEA obtained is 21.07 which is further used for evaluating and mapping the current level of occupational safety of workers in industry. In order to estimate OSEA, a questionnaire-based survey was conducted in 30 medium sized manufacturing industries (MSMI) of Punjab. The results revealed that the OSEA index of MSMI lies in the range of 8.90 - 17.79. Moreover, it is concluded that OSEA index is a useful tool to measure the existing level of occupational safety of workers in the industry, which can be implemented to assess the level of workplace safety.
Keywords: content validity index (CVI); Delphi method; medium sized manufacturing industries (MSMI); occupational safety level; OSEA; safety index (SI).
A front- and rear-view assistant for older cyclists; evaluations on technical performance, user experience and behaviour
by Carola Engbers, Rosemary Dubbeldam, Niek Kamphuis, Stefanie De Hair-Buijsen, Frank Westerhuis, Jaap Buurke, Dick De Waard, Johannes Rietman
Abstract: The older cyclist is more prone to get cycling accidents than younger cyclists. To support the older cyclist, a rear- and front-view assistant were developed that warns the cyclist of approaching traffic. User tests to evaluate system performance, user-experience and effects on behaviour were performed with 20 older cyclists (>64 years) on a predefined route outdoors with and without support from both assistants. During this route, the cyclist was confronted with two controlled scenarios with an overtaking and an oncoming cyclist. The participants cycling behaviour was assessed by measuring lateral distance to the other cyclist, and distance maintained to the verge. The assistants had no effect on experienced mental workload. Both assistants received positive evaluations, although the rear-view assistant was experienced as more useful. Using the front-view assistant resulted in less lateral distance to the approaching oncoming cyclist, while the use of the rear-view assistant did not have effects on lateral distance.
Keywords: Assistance; cycling; ageing; safety; support; accidents; elderly; mental workload; acceptance; lateral position.
A Theoretical Model of Human-Automation Interaction Grounded in Resource Allocation Policy during Automated Driving
by Yusuke Yamani, William Horrey
Abstract: With the aim of enhanced safety and mobility, automated driving systems have already begun to allow drivers the ability to operate vehicles with reduced driver control. However, research in other professional domains of Human Factors indicates that automated systems of different types, purposes, and characteristics can often be used by human drivers counterproductively, leading to misuse or disuse of automation. This paper outlines characteristics of an integrative model of human-automation interaction (HAI) based on attentional resources and allocation policy in order to help guide the systematic research on issues related to automated driving. The model builds upon a human information-processing model (Wickens et al., 2013) and focuses on the effective allocation of attentional resources to different perceptual, cognitive, and response stages when interacting with varying types and levels of automation (Parasuraman et al., 2000). The closed-loop mechanism allows drivers to evaluate joint human-machine performance and modulate the allocation policy, which in turn is influenced by many other factors. The model can additionally account for two well-known phenomena in the literature of HAI, complacency and automation bias, and offers guidance of systematic research on drivers attentional state in automated driving systems.
Keywords: Automated Driving; Human-Automation Interaction; Attentional Resources; Information Processing; Attention Allocation; Multitasking.
Analysis of Work-Related Musculoskeletal Disorders and Ergonomic Posture Assessment of Welders in Unorganized Sector: A Study in Jalandhar, India
by Manish Dev, Arvind Bhardwaj, Sarbjit Singh
Abstract: Work-related musculoskeletal disorders (WMSDs) are the major risk factors in the life of blue-collar workers. These disorders not only lead to their ill health but cause low productivity too. The current study was undertaken to investigate the risk factors of work-related musculoskeletal disorders and postural discomfort among welders working in unorganized manufacturing units in Jalandhar, India. A cross-sectional survey was carried out among 60 welders working in roadside manufacturing units to investigate the level of musculoskeletal disorders. Nordic Musculoskeletal Disorder questionnaire was used to investigate the WMSDs during last 12 months. The findings reveal that age, BMI, working hours and work experience have a significant association with WMSDs in some of the cases. Pain/Discomfort in neck and hand/wrist were the leading in upper body part whereas pain/discomfort in lower back was leading in the lower body part and the most commonly reported WMSDs among the respondents. Furthermore, RULA and REBA scores reveal that the population of welders is at more risk of developing WMSDs and working postures of welders are required to be changed immediately to reduce the risk of developing musculoskeletal disorders and to ensure the physical and psychological well-being of welders.
Keywords: Work-Related Musculoskeletal Disorders; WMSDs; Posture; Welders; Rapid Upper Limb Assessment; RULA; Rapid Entire Body Assessment; REBA; Unorganized Sector.
Low back pain assessment using Surface Electromyography among industry workers during the repetitive bending tasks
by Shankar Subramaniam, Naveenkumar Raju, Pradeep Srinivasan, Karthick Jeganathan, Srinivasan Jayaraman
Abstract: Hand screen printing (HSP) involves repetitive tasks, prolonged standing, and maintenance of awkward, uncomfortable posture, that leads to musculoskeletal disorders. Low back pain (LBP) prevalence is higher among these workers. The present study aims towards quantitative analysis of low back pain for the prolong printing task among HSP workers, by monitoring the muscular activity and bending angle. The surface electromyogram (sEMG) and goniometer signals were used to monitor the erector spinae muscles group and thoracic bending angle respectively for20 minutes of printing task. The study population was divided into two groups, such as LBP and control groups, based on workers physical fitness. The study results infers that, muscle MPF difference of LBP is significantly different than the control group. Further, result finding suggest that, the erector spinae thoracic muscle group inflicting the muscle fatigue among the LBP group HSP workers. The current finding indicates that, LBP group are easy prone to muscle fatigue and likely to high possibility of worsening back pain due toprolong monotonous and repeated bending task in printing environment.
Keywords: Workplace ergonomics; SEMG; Low Back; Muscle fatigue; Textile industry; Repetitive task; MPF.
Rapid Serial Visual Presentation: degradation of inferential reading comprehension as a function of speed
by Francesco Di Nocera, Orlando Ricciardi, James Juola
Abstract: There is increasing interest in the readability of text presented on small digital screens. Designers have come up with novel text presentation methods, such as moving text from right to left, line-stepping, or showing successive text segments such as phrases or single words in a RSVP format. Comparative studies have indicated that RSVP is perhaps the best method of presenting text in a limited space. We tested the method using 209 participants divided into six groups. The groups included traditional reading, and RSVP reading at rates of 250, 300, 350, 400, and 450 wpm. No significant differences were found in comprehension for normal reading and RSVP reading at rates of 250, 300 and 350 wpm. However, higher rates produced significantly lower comprehension scores. It remains to be determined if, with additional practice and improved methods, good levels of reading comprehension at high rates can be achieved with RSVP.
Keywords: reading; rapid serial visual presentation; RSVP; comprehension; optimal speed rate; Spritz.
Distracted Driving Effect on Discharge Rate at Signalized Intersections in Kuwait
by Fahad Alrukaibi, Sharaf AlKheder, Saleh Al-Otaibi
Abstract: In this study an attempt was performed to investigate the relation between distracted driving and the rate of discharge. In order to get an overview of the drivers intentions and attitudes towards distracted driving, a questionnaire was formed and randomly distributed to 400 persons. Also, observations were conducted to study the drivers behaviours at signalized intersections and obtain the frequencies of performing distracted driving. The results of both the questionnaire and the observation were integrated to compare drivers perceptions regarding distracted driving and the actual frequencies of such a behaviour. The observation covered four pre-timed intersections with four approaches at Al-Salmiya area; which is one of the largest commercial areas in Kuwait with many congested intersections. The results of the questionnaire and the observation form were analysed by a statistical analysis software called Statistical Package for the Social Sciences (SPSS). Discharge rate (Q) and the distraction percentage were also calculated. The results of the questionnaire showed that although there is a rising awareness of the risk of distractions sources, most drivers still keep unacceptable performance level. The observation results showed that the discharge rate is inversely related to distraction percentage.
Keywords: Driving behaviour; distractions; signalized intersections; Kuwait.
A Comparative Field Usability Study of two Lighting Measurement Protocols.
by Roberto German Rodriguez, Juan Manuel Monteoliva, Andrea Pattini
Abstract: We developed a lighting measurement protocol (PC-SRT) for Android mobile devices as a replacement of the Argentinean currently mandatory pen-and-paper measurement protocol (SRT-P), and compared their usability in a field study (n=26) by means of the System Usability Scale (SUS). Descriptive statistics showed that PC-SRT (SUS=58.7; SD=14.9; lower marginally acceptable usability) outscored SRT-P (SUS=47.5; SD=14.5; unacceptable usability). The PC-SRT also performed better in both Ease of Use and Learnability factors. An item-by-item analysis compared the behaviour of each standardized item score; Mann-Whitney test results showed statistically significant differences in SUS-Q1 (U=36; p=.011), SUS-Q2 (U=35; p=.01), SUS-Q4 (U=46.5; p=.05), and SUS-Q7 (U=39; p=.019). These results show that although PC-SRT gathers more data in a wider variety of aspects of the visual environment, users tended to perceive it as easier to use, encouraging the adoption of our proposed lighting measurement protocol for mobile devices.
Keywords: usability; comparative field study; lighting measurement protocol; SUS; system usability scale; human factors.