Li, MingmingGuo, FuRen, ZenggenDuffy, Vincent G....
12页
查看更多>>摘要：This study aims to characterize the fixation pattern and neutral dynamics underlying affective impressions on humanoid robot appearances, which have a moderate anthropomorphism, to provide an objective evaluation of the affective impressions. Thirty appearance pictures of existing humanoid robots leaving negative, neutral, or positive impressions were selected online. Users' eye-tracking and electroencephalography signals for the ap-pearances were co-registered in a free viewing paradigm, and eye-tracking metrics and eye fixation-related potentials were extracted. The results showed that the head attracted the most eye-tracking metrics, including glance count, fixation count, fixation time, and fixation duration. The torso attracted the second most, the legs and the hands attracted the third most, and the arms and feet drew the least. Humanoid robot appearances giving positive impressions caught less glance counts and shorter fixation duration than the appearances giving negative or neutral impressions on both partial and whole appearances. The appearances giving positive impressions evoked the smallest P1 amplitude, and the appearances giving neutral impressions evoked the largest P1 amplitude, compared with that giving negative impressions. The findings suggest that glance count and fixation duration could distinguish the positive impression on humanoid robot appearances, and the P1 amplitude could distinguish the three affective impressions.Relevance to industry: These findings could promote the understanding of fixation pattern on humanoid robot appearances, which could be referred to directly when designing appearances for humanoid robots. Moreover, this study could provide designers with a visual and neural method of evaluating affective impressions on hu-manoid robot appearances in free viewing.
Jakobsen, LasseLysdal, Filip GertzBagehorn, TimoKersting, Uwe G....
7页
查看更多>>摘要：Slipping is a frequent cause of occupational accidents. This is often due to an insufficient available coefficient of friction (ACOF) of footwear. The aim of this study was to present a footwear ACOF test setup, and to evaluate it based on device requirements presented in the ISO 13287 test standard. One left Airtox TX2 shoe underwent slip resistance measurements under three test modes (Forward flat slip, backward slip on the forefoot at angled contact and forward heel slip at angled contact), with six contaminant conditions (dry steel, dry tile, glycerine on steel, glycerine on tile, canola oil on steel and canola oil on tile). The test setup was successfully able to measure ACOF in close accordance to the ISO 13287 test standard with a good repeatability. Furthermore, the test setup can alter biomechanical and tribophysical testing conditions, which may provide more valid footwear ACOF measurements in the future.Relevance to industry: The setup can accommodate biomechanical and tribophysical testing conditions, hence the setup can be a tool for accessing more valid ACOF measurements -closer to real world slip events. Footwear manufactures or researchers, with the goal of improving footwear slip resistance, can implement the setup.
查看更多>>摘要：Researchers in production and operations management have studied the effect of worker learning and forgetting on system performance for decades. It remains an active research topic. Those studies have assumed that production interruptions (or production breaks) cause forgetting, which deteriorates performance. Research on human working memory provides enough evidence that continuous forgetting, precisely cognitive interference, results from overloading the memory with information. Despite the evidence, few studies have incorporated it into learning curve models. This paper presents an enhanced version of the power learning curve that accounts for a variable degree of interference when moving from a production cycle to the next. It adopts the concept of memory trace decay to measure the residual (interference-adjusted), not the nominal (maximum) cumulative experience. We test the developed model against learning data from manual assembly and inspection tasks, with varying numbers of repetitions and breaks. We also test three alternative power-form learning and forgetting curve models from the literature. The results show that the interference-adjusted model fits the data very well. The proposed learning and forgetting model and its individualized cumulative metrics can help identify struggling workers early and release precocious learners earlier than expected. As such, the model gives insights for managers on the occurrence of interference to enable individual learning support.
查看更多>>摘要：With the rapid development of logistics, forklifts are increasingly used in warehouses and other industrial sites. Drivers of the forklifts experience vibration and noise affecting the ride comfort during work. Focusing on the hand and arm vibration, this paper proposed a hybrid hand-arm model to represent the vibration transmitted from the steering wheel of a forklift to the hand and arm with different grasping forces. The model consisted of the shoulder, upper arm, forearm, and hand connected by joints with stiffness and damping. The hand model included the palm and five fingers, with each finger being modelled with the distal, middle, and proximal segments interconnected via revolute joints. Surface-to-surface contact was adopted between the hand and handle, and self-contact was defined for the hand. Moments were applied to finger joints to simulate the active muscle forces when gripping the handle. The material properties of the skin, bones, and subcutaneous tissues were determined based on published literatures. The parameters were further adjusted to match the contact pressures and vibrations of the hand and arms when griping a vibrating handle reported in literatures. The calibrated model was then used to predict the vibration transmissibility of the hand-arm system from the steering wheel of a working forklift and reasonably good results were obtained. The results showed that the developed model accounting for the grasping force and the contact conditions between the hand and handle is capable of predicting the vibration transmission of the hand-arm system of vehicle drivers.
查看更多>>摘要：Introduction: In April 2020, novel coronavirus SARS-CoV-2 (COVID-19) produced an ongoing mass fatality event in New York. This overwhelmed hospital morgues necessitating emergent expansion of capacity in the form of refrigerated trucks, trailers, and shipping containers referred to as body collection points (BCPs). The risks for musculoskeletal injury during routine and mass fatality mortuary operations and experiences of decedent handlers throughout the "first wave" of COVID-19 are presented along with mitigation strategies Methods: Awareness of the high rates of musculoskeletal injury among health care workers due to ergonomic exposures from patient handling, including heavy and repetitive manual lifting, prompted safety walkthroughs of mortuary operations at multiple hospitals within a health system in New York State by workforce safety specialists. Site visits sought to identify ergonomic exposures and ameliorate risk for injury associated with decedent handling by implementing engineering, work practice, and administrative controls. Results: Musculoskeletal exposures included manual lifting of decedents to high and low surfaces, non-neutral postures, maneuvering of heavy equipment, and push/pull forces associated with the transport of decedents Discussion: Risk mitigation strategies through participatory ergonomics, education on body mechanics, development of novel handling techniques implementing friction-reducing aides, procurement of specialized equipment, optimizing BCP design, and facilitation of communication between hospital and system-wide departments are presented along with lessons learned. After-action review of health system workers' compensation data found over four thousand lost workdays due to decedent handling related incidents, which illuminates the magnitude of musculoskeletal injury risk to decedent handlers.
查看更多>>摘要：The design of many items (e.g., web pages, banknotes) is influenced by the features to which designers expect users will attend. However, there is a dearth of research regarding which features individuals do attend to on banknotes and whether these are consistent with the expected focus of attention. The present study investigated where people look when they are looking at banknotes. We recorded the eye movements of laypersons to determine which banknote features draw the attention of observers. Images of banknotes from seven countries and in a variety of denominations were viewed (and eye movements were recorded) for 7 s in each of three viewing contexts: Art, Counterfeit, and Spatial Layout. Interest areas (e.g., features of interest) were outlined and then the duration of fixations within those areas were analyzed to examine which features were attended within the different contexts. Results suggested that the portraits that are commonly used on banknotes were not generally examined in the Counterfeit condition (irrespective of whether the entire portrait, the face, or even only the eyes were considered), but these features were examined more within an Art or a Spatial Layout context. Further, results suggested that signatures and text on banknotes tended to be examined in a Counterfeit and a Spatial Layout context as compared to an Art context. Although images were viewed more in the Art context as compared to a Counterfeit or a Spatial Layout context, security features were viewed more in the Counterfeit context than in the Art and the Spatial Layout contexts. Denominations were viewed similarly in the Counterfeit and the Spatial Layout contexts but more than in the Art context. Finally, areas with highly salient but low-level features (e.g., intensity, colour) that were expected to draw attention were not viewed in any of the contexts. The results have implications for how individuals view banknotes, generally, and also which regions tend to draw attention.
Nolasco, S.Amaro, C. M.Roseiro, L.Castro, M. A....
7页
查看更多>>摘要：The vibration transferred to the arm of the badminton player through the racket can be associated with disease. This study analyzed the induced hand-arm vibrations (HAV, comparing two rackets with different stiffness, in movements with three handgrips (FH-forehand; FHR-forehand around the head, BH-backhand). The racquet was instrumented with a triaxial piezoelectric accelerometer, and the time of daily exposure to these vibrations was calculated according to ISO 5349 -1,2, as well as the time required to develop white finger disease with a 10% probability. The main goal of this study is to examine the influence of the racket stiffness on the HAV, and understand the most critical smash movement for the HAV. The results indicate that the HAV vibrations are superior in the less rigid racket, being the daily exposure to these superior to the one defined by the own norms. It is also noted that the movement with the forehand grip is the most critical in what the induced vibrations are concerned. No differences in vibrations between the FH and FHR are observed.
查看更多>>摘要：Although the Functional Resonance Analysis Method (FRAM) is a well-established approach to visualizing complex systems' operations in terms of functions, further improvements are required to examine systems' performance through functionality. This study aims to develop an approach to couple the FRAM to reinforcement learning (RL) to explore complex operations. The developed approach is called the functional RL approach and constitutes a novel way of using a FRAM model to explore functionality using an artificial intelligent (AI) agent who responds to reward values assigned to functional parameters. To exemplify the approach, an agent is employed to perform the role of a patient and explore a functional environment generated by the FRAM. Reward values are considered to motivate the agent in order to explore the environment to achieve its objective. The ability of the developed approach is examined using different scenarios implemented in healthcare operations. The results of using the functional RL approach indicate that the approach is able to specify the functional route taken by the agent and to examine the performance of the system based on accumulated rewards. The outcomes of this study demonstrate that the developed functional RL approach provides a novel means to explore operational environments to identify the routes that have potential to affect the system performance. This method can be used as a powerful way to assess how a system performs under different management structures.
Fournier, Daniel E.Dickerson, Clark R.La Delfa, Nicholas J.Lockley, Rebecca M. E....
9页
查看更多>>摘要：Occupational shoulder overexposures, including increased muscle activity and associated localized muscle fa-tigue, typically scale with manual exertion height during static or intermittent overhead work. It is unknown how this response is affected during complex (i.e. multi-directional and varying magnitude) manual force exertions, and how this work profile may attenuate task endurance. The purpose of this study was to evaluate the influence of manual exertion height on shoulder muscle fatigue responses during a multi-directional manual exertion protocol. Fourteen participants completed a shoulder fatiguing protocol by exerting manual forces (push up, down, left, and right) at three vertical hand location heights (low, shoulder and overhead). Decline in strength, myoelectric indicators of fatigue, ratings of perceived discomfort and endurance time were used to track the progression of fatigue at the different height conditions, and differential effects due to direction of exertion were also examined. The overhead and shoulder height conditions resulted in significantly increased muscle activa-tion, discomfort and strength decline in comparison to the low condition. Fatigue responses between overhead and shoulder level work were generally similar, as no differences existed in endurance time, RPD and mean power frequency for these conditions, but the overhead condition resulted in a substantial 18% reduction in downwards strength. The downwards exertions seemed to elicit the greatest fatigue response, despite the up-wards direction requiring the highest global muscle activity. These results add evidence that repetitive overhead work should be avoided when possible, but provides novel insight on how direction of force application can be further considered in design recommendations.
Alhaag, Mohammed H.Ramadan, Mohamed Z.Al-harkan, Ibrahim M.Alessa, Faisal M....
10页
查看更多>>摘要：Purpose: Maintenance workers often perform tasks with high levels of complexity. The association between maintenance task complexity and muscle fatigue needs further investigation. In this study, the effect of maintenance task complexity on muscle fatigue and perceived workload was evaluated. Methods: Fifteen male participants performed two maintenance tasks with two levels of complexity: repairing a gearbox of piston pump (complex task) and repairing a faulty pump housing (simple task). The electromyographic (EMG) activity data from six muscle sites of the neck and the dominant side of the shoulder and arm were recorded. Muscle fatigue was assessed using normalized root-mean-square (RMS) of EMG data and the slopes of median frequency (MF) and mean power frequency (MPF). The NASA Task Load Index (TLX) was utilized as a secondary subjective measure for perceived workload. Findings: Compared to the simple task, performance of the complex task was associated with significantly higher values of RMS EMG (29.92% in average) for all sampled muscles. The slopes of MF and MPF for the flexor carpi radialis muscle during the complex task were significantly lower than that of the simple task. Also, TLX scores for the complex task were significantly higher than those for the simple task. Conclusions: Findings of this study indicate that, within the sampled muscles, the complexity of the maintenance task could cause more muscle fatigue, especially for the forearm muscle. The results of the TLX scores suggest that task complexity could contribute to a significant increase in mental, physical, and temporal demands, effort, and frustration. Relevance to industry: The findings of this study could be utilized to improve the designs of industrial maintenance tasks with respect to human ability and performance.
NSTL
Elsevier