Development and validation of a behavioural video coding scheme for detecting mental workload in manual assembly.

Manual assembly in the future Industry 4.0 workplace will put high demands on operators' cognitive processing. The development of mental workload (MWL) measures therefore looms large. Physiological gauges such as electroencephalography (EEG) show promising possibilities, but still lack sufficient reliability when applied in the field. This study presents an alternative measure with a substantial ecological validity. First, we developed a behavioural video coding scheme identifying 11 assembly behaviours potentially revealing MWL being too high. Subsequently, we explored its validity by analysing videos of 24 participants performing a high and a low complexity assembly. Results showed that five of the behaviours identified, such as freezing and the amount of part rotations, significantly differed in occurrence and/or duration between the two conditions. The study hereby proposes a novel and naturalistic method that could help practitioners to map and redesign critical assembly phases, and researchers to enrich validation of MWL-measures through measurement triangulation. Practitioner summary: Current physiological mental workload (MWL) measures still lack sufficient reliability when applied in the field. Therefore, we identified several observable assembly behaviours that could reveal MWL being too high. The results propose a method to map MWL by observing specific assembly behaviours such as freezing and rotating parts. Abbreviations: MWL: mental workload; EEG: electroencephalography; fNIRS: functional near infrared spectroscopy; AOI: area of interest; SMI: SensoMotoric Instruments, ETG: Eye-Tracking Glasses; FPS: frames per second; BORIS: Behavioral Observation Research Interactive Software; IRR: inter-rater reliability; SWAT: Subjective Workload Assessment Technique; NASA-TLX: National Aeronautics and Space Administration Task Load Index; EL: emotional load; DSSQ: Dundee Stress State Questionnaire; PHL: physical load; SBO: Strategisch Basis Onderzoek.

People with disabilities as product innovators: a pilot study.

PURPOSE: The purpose of this study is to explore the rate of product innovation among persons with disabilities, how they are diffused and the general value of these developed solutions for persons without disabilities. MATERIALS AND METHODS: A sample of participants (n = 178) completed a self-administered questionnaire, which included information about their disability, disability burden, general unmet product needs, the impact of the developed solution on their quality of life and how solutions were diffused. We analyzed solutions both for their novelty and for their general value. RESULTS: Close to 45% of respondents reported having developed a solution, with 9.55% solutions judged as novel. Additionally, 6.8% of respondents developed a solution of general value to non-disabled users. CONCLUSIONS: Our results suggest that people with disabilities are actively involved in product development and that their solutions have a positive impact on their lives. Furthermore, many reported solutions also provide value for non-disabled persons, suggesting that persons with disabilities may be an important source of innovation. Implications for Rehabilitation Persons with disabilities are frequently engaged in developing solutions that meet their unmet product needs. Most solutions are not diffused beyond their immediate social circle. Solutions have a significant impact on the self-reported quality of life of participants.