International Journal of Industrial Ergonomics最新文献

In an era where digital multitasking is universal, the necessity to switch between devices is vital. The effect of switching modes between devices on the user experience remains unclear. This study investigates the impact of switching modes on task performance and user perception within interconnected device environments. A within-subject experiment utilizing memory recall tasks was implemented to test three switching modes: seamless switching, passive switching, and switching with feedforward and feedback. Task accuracy rate, perceived interruption, perceived control, and behavioral intention were measured. Results indicated that seamless switching outperformed passive switching in task accuracy rate. Passive switching elicited the highest level of perceived interruption, while switching with feedforward and feedback substantially improved the perceived control of users over seamless switching. The behavioral intention to use seamless switching and switching with feedforward and feedback was considerably higher than that for passive switching. This research provides insights into the comparative benefits of seamless switching and switching with feedforward and feedback, particularly regarding their influence on user perception. Practical implications for the design of interconnected device switching and the management of device ecosystems are also presented.

The effects of circadian rhythms and night work on performance have been extensively studied using standardized, non-work-related tasks in laboratory settings. However, field research on work performance is scarce in this domain. This study addresses this gap by analyzing four million behavioral responses from 1437 security officers at an international airport. We compared threat detection performance during the routine security screening of passengers' baggage X-ray images across night shifts (shift starting between 0:00 and 2:59), early morning shifts (starting between 3:00 and 5:59), and standard morning shifts (starting between 6:00 and 7:59). Processing times followed the circadian rhythm of attention found in laboratory studies, indicating that the rhythm affects real-life work performance. False alarm rates (i.e. false target present responses) were slightly higher during night and early morning shifts than during standard morning shifts, with no significant difference in the security-relevant hit rates (i.e. true target present responses). Furthermore, we found no performance differences between night work and early morning shifts, suggesting that both can disrupt employees’ natural sleep patterns with implications on performance.

This study explores the impact of trust and perceived justice on task performance within UAE public sector organizations, emphasizing the mediating role of autonomy and the moderating effect of organizational culture. This research was driven by gaps in the current understanding of how individual perceptions of fairness and trust impact practical outcomes in the public sector. Through a survey of 273 public sector employees and structural equation modeling, this study demonstrates how trust and perceived justice significantly enhance task performance, with autonomy serving as a crucial mediator. Organizational culture also plays a complex role in moderating these effects, adding a cultural context layer to the theoretical framework grounded in social exchange theory. This study contributes to this field by providing empirical evidence supporting the enhancement of autonomy and justice perceptions to improve employee performance in the public sector. This contribution is particularly significant as it challenges traditional views on the trust-autonomy relationship and offers new insights into the role of organizational culture. By highlighting these dynamics, this study fills a crucial gap in the literature and also offers a model that can guide future research and practical applications in similar contexts. The findings underscore the necessity of fostering trust and perceived justice within organizations, recommending that leaders focus on enhancing autonomy and carefully consider the influence of organizational culture. This approach promises to improve task performance and employee satisfaction, thereby contributing to a more effective administration and service delivery in the public sector.

Virtual reality (VR) has emerged as a promising tool for training. Our study focused on training for forklift driving, to address an ongoing worker shortage, and the unknown impact of repeated VR training on task performance and kinematic adaptations. We trained 20 novice participants using a VR forklift simulator over two days, with two trials on each day, and including three different driving lessons of varying difficulties. Driving performance was assessed using task completion time, and we quantified kinematics of the head, shoulder, and lumbar spine. Repeated training reduced task completion time (up to ∼29.8% of initial trial) and decreased both kinematic variability and peak range of motion, though these effects were larger for lessons requiring higher precision than simple driving maneuvers. Our results highlight the potential of VR as an effective training environment for novice drivers and suggest that monitoring kinematics could help track skill acquisition during such training.

Developing pilot workload assessment method is conducive to improving pilot work efficiency and enhancing the reliability of flight operations. In this study, a pilot workload model based on task complexity analysis is built to predict the changing trend of workload under various task scenarios with different task difficulties. Based on multiple resource theory and entropy theory, a pilot workload model is constructed by integrating the analysis of node task complexity and structure task complexity. Further, the Bedford scale and time pressure survey are both adopted to subjectively investigate the workload of 25 flying cadets in the traffic pattern task to verify the model. The correlation coefficients between the theoretical prediction results and the actual measurement results are not less than 0.85, supporting the validity of the model. Besides, compared with the original Bedford workload scale, consideration of time pressure can effectively improve the consistencies between the theoretical prediction results of the model and the actual evaluation results of the flying cadets, indicating the advantage of strengthening the time pressure dimension when using the classic Bedford workload scale to measure the pilot workload. The pilot workload measurement model based on task complexity analysis proposed in this study can provide method support for the optimization designs of flight tasks and pilot training.

In complex human-computer interactions, issues such as task failures, system malfunctions, and frequent accidents caused by user errors are common. Therefore, it is necessary to study complex system interactions to enhance overall efficiency. This study focuses on the task interface of a digital twin system for computer numerical control (CNC) machine tools and examines the relationship between the user mental model and interface design elements. Key mental information is obtained through questionnaires and interviews, forming the basis for establishing a user mental model. High-frequency information words are extracted, experimental samples are designed, and importance rating surveys are conducted. Quantitative analysis methods, including factor analysis and weight calculation, are utilized to analyze the needs of target users. Consequently, a user demand hierarchy model is constructed. This approach aims to effectively reduce user errors in the human-computer interaction process within complex systems and enhance cognitive efficiency.

This study assessed the accuracy of L5/S1 moment estimates calculated with an Inertial Motion Capture (IMC) system during an asymmetrical and variable height lifting task. The effects of load weight, asymmetry, and lifting height on estimates of lumbar moment have not been comprehensively considered in studies using IMC systems. Thirty-six participants engaged in tasks involving three loads, lifting heights, and trunk rotation angles. Lumbar moments were calculated using bottom-up and top-down biomechanical models. Gold-standard Optical Motion Capture (OMC) and Force Plates (FP) were used as the reference. A randomized block partially confounded design was used to compare the root mean square errors (RMSE) between the IMC and OMC-based reference estimates. The IMC system's estimated peak moments were 12%–13% lower than those estimated using the gold standard OMC-BU inverse dynamics, while the RMSE varied between 19 and 21 Nm. A Load*Height interaction was found; a trend was identified where the RMSE values increased as both the load and height levels increased. The angle did not show a significant effect on any of the tested scenarios. A close correspondence between the IMC and OMC-based moment estimates was established, with the load being the main factor affecting the differences between systems. The IMC system shows potential for use in occupational settings to capture data on the lumbar moments of workers, which could be utilized to assess ergonomic risk.

It is a stressful ordeal in general to buy bras online aimlessly. The wise approach for eCommerce platform is to use emotion recognition to effectively assess consumers’ needs through the bra images, which can quickly close their preferences and accurately recommend them suitable bras. However, the significant physiological features that can be used for emotion recognition in fashion are still in the exploratory stage. This study focuses on the relationship between cardiac activity and emotional responses (the different levels of Satisfaction (S) and Attractiveness (A) under the stimulation of bra images. Firstly, we labelled 96 bra images in the dimensions and selected 45 bra images to make three groups of emotional stimuli using k-means clustering analysis. Then, we collected Photoplethysmogram (PPG) signals from 46 subjects consisting of 11 males and 35 females simulated by three groups of the stimuli, extracted 10 metrics of heart rate variability (HRV), and then analyzed the relationships between HRV and emotions based on their subjective evaluation. The males and females have different cardiac activity patterns under the same emotion, that the parasympathetic of males are more active than females. In a non-neutral emotion, the parasympathetic nervous system would keep an activated state. However, it is dominated by the parasympathetic nervous system whether in high or low satisfaction. While high and low attractiveness are respectively dominated by the sympathetic and parasympathetic nerves. The results of this study have certain significance for understanding the physiological phenomenon of emotions and further help to explore emotion recognition technology which can be used in product development to enhance the competitiveness of enterprises.

Background

The study aimed to compare the effects of medium hardness and high hardness arch-support insoles, with the latter modified by a soft forefoot pad, on foot pressure distribution and muscle activation during high-load carrying tasks in authentic mountainous trail environments.

Methods

Sixteen male mountaineer porters with experience in high-load carrying tasks participated in the experiments. They wore commercially available prefabricated arch-support insoles, specifically referred to as medium hardness arch-support material (MH) and high hardness arch-support material attached a 1-mm soft sponge pad to the forefoot area (HHSF) during uphill and downhill walking tasks with a 25-kg load. Foot pressure and muscle activation were measured using wireless pressure distribution insoles and a wireless surface electromyography system, respectively.

Results

The HHSF showed significantly higher perceived comfort scores and reduced foot pressure in specific regions during downhill walking (p < 0.05). It exhibited increased peak foot pressure in the forefoot during uphill walking (p < 0.05). The MH showed greater foot pressure in the second metatarsal during downhill walking and a larger contact area in the midfoot during uphill walking (p < 0.05). Muscle activation did not differ significantly between the two insoles (p > 0.05).

Conclusion

The study indicates that combining a high hardness arch-support insole with a soft forefoot pad may enhance comfort and potentially reduce foot injury risks, and improves foot propulsion and pressure distribution.

To enhance the pant fit for individuals, this study proposed a method for constructing a 3D waist-leg mannequin based on body images and 3D point-clouds of young women. A total of 288 females aged 18–25 were measured using 3D body scanner and 2D image-shooting method to obtain 3D point-cloud data and body images. The 3D point-cloud data were analyzed to extract 33 sectional curves, including the cross-sectional curves and crotch curve, to identify key points on each curve. For the body images, key parameters related to curve position and shape, such as height, width, and thickness, were automatically extracted for modelling parameters. Curve generation rules were established based on correlation and regression analysis of the key points. The Individualized 3D mannequin was simulated by adjusting the curve centers at each characteristic position to align with the body images, and was validated by comparing the body sizes of the 3D mannequin with the actual measurements. The results indicated that the final simulated mannequin accurately represents the basic characteristics of the waist-leg shape, with significance values above 0.05, which showed the feasibility of the modelling method. Furthermore, 73.9% of the samples had an absolute error of less than 1 cm between the 3D mannequin and the actual measurements. This study can facilitate 3D body modelling from body images, and provide a reference to develop individualized apparel patterns for clothing customization.