The user experience of violinists playing with a novel ergonomic chinrest: An evaluation on motivation, usage behaviour, usability and acceptance.

BACKGROUND: This study focuses on the user experience of a novel developed ergonomic chinrest (EC), customised to accommodate the individual violinist's anthropometry and playing style. The EC was recently tested for biomechanical effect, but the violin player's motivation, usage behaviour, usability and acceptability may be equally important. OBJECTIVE: To explore the user experience of violinists who used the novel EC with a low shoulder rest for two weeks. Through that experience, we wanted to learn about the potential user barriers and facilitators related to their motivation, usage behaviour, usability, and acceptability, when trying a new product. METHODS: Thirty-eight professional violinists participated and evaluated motivation, user behaviour, usability and acceptance using a 5-point Likert scale and open-ended questions. RESULTS: Participants showed high motivation hoping to improve posture, reduce muscle tension and enhance performance. Usage behaviour was also high, while product appearance, adjustment time, and sound impact were negatively evaluated. However, 37% planned to continue to use EC after the study. CONCLUSION: Participants showed high motivation and usage behaviour but faced challenges with product appearance, adjustment time, and sound impact compared to their usual chinrest. Incorporating user feedback and addressing design and usability challenges can enhance the user experience.

Innovative features and functionalities of an artificial pancreas system: What do youth and parents want?

AIMS: Participant-driven solutions may help youth and families better engage and maintain use of diabetes technologies. We explored innovative features and functionalities of an ideal artificial pancreas (AP) system suggested by youth with type 1 diabetes and parents. METHODS: Semi-structured interviews were conducted with 39 youth, ages 10-25 years, and 44 parents. Interviews were recorded, transcribed and coded using thematic analysis. RESULTS: Youth (72% female, 82% non-Hispanic white) were (M ± SD) ages 17.0 ± 4.7 years, with diabetes for 9.4 ± 4.9 years, and HbA1c of 68 ± 11 mmol/mol (8.4 ± 1.1%); 79% were pump-treated and 82% were continuous glucose monitor users. Of parents, 91% were mothers and 86% were non-Hispanic white, with a child 10.6 ± 4.5 years old. Youth and parents suggested a variety of innovative features and functionalities for an ideal AP system related to (1) enhancing the appeal of user interface, (2) increasing automation of new glucose management functionalities, and (3) innovative and commercial add-ons for greater convenience. Youth and parents offered many similar suggestions, including integration of ketone testing, voice activation, and location-tracking into the system. Youth seemed more driven by increasing convenience and normalcy while parents expressed more concerns with safety. CONCLUSIONS: Youth and parents expressed creative solutions for an ideal AP system to increase ease of use, enhance normalcy, and reduce burden of management. Designers of AP systems will likely benefit from incorporating the desired preferences by end users to optimize acceptance and usability by young persons with diabetes.

Are female soldiers satisfied with the fit and function of body armour?

Design and development of contemporary military body armour has traditionally focused primarily on male soldiers. As the anthropometric body dimensions of male and female soldiers differ, we aimed to determine whether current body armour was meeting fit and functional requirements of female soldiers. One-hundred and forty-seven female Australian Defence Force soldiers completed a 59-item questionnaire regarding the fit and function of current body armour. Most (68%) participants reported wearing ill-fitting body armour, which was associated with increased total musculoskeletal pain and discomfort, as well as pain at the shoulders, abdomen, and hips. Body armour that was too large was more likely to interfere with task performance when it was integrated with a combat belt, as well as when female soldiers performed operationally representative tasks. Modifying body armour design and sizing to cater to the anthropometric dimensions of female soldiers is recommended.

Evaluation of the effect of a newly developed steering unit with enhanced self-alignment and deadband on mental workload during driving of agricultural tractors.

The aim of present study was to investigate the effect of a newly developed steering unit with enhanced self-alignment and deadband on mental workload (MW) during heavy vehicle operation. Fourteen participants performed two tasks consisting of a lane keeping and a double lane shift with two tractors equipped with 1) a conventional and 2) an enhanced steering system. Physiological measurements, i.e., electromyography, electrodermal activity and heart rate were recorded during the tasks. Furthermore, performance measurements and subjective perception of MW were collected. Present study demonstrated that participants perceived the enhanced steering system requiring less mental demands to operate. Participants improved their performance during the lane keeping task and tended to improve in the double lane shift task with the enhanced system. Physiological measurements did not reveal differences between the steering systems. This study highlighted the dissociation of subjective indices of mental workload from physiological indices in driving of heavy vehicles.

Exploring the need for and application of human factors and ergonomics in ambulance design: Overcoming the barriers with technical standards.

Ergonomic risk factors, such as excessive physical effort, awkward postures or repetitive movements, were the leading causes of injuries amongst EMS workers in the United States, of which 90% were attributed to lifting, carrying, or transferring a patient and/or equipment. Although the essential tasks of patient handling, transport, and care cannot be eliminated, the design of ambulances and associated equipment is modifiable. Our aims were to identify the extent of Human Factors and Ergonomic (HFE) considerations in existing ambulance design standards/regulations, and describe how HFE and the standards/regulations were applied in the EMS system. Through an extensive environmental scan of jurisdictionally relevant standards/regulations and key informant interviews, our findings demonstrated that existing standards/regulations had limited considerations for HFE. As a result, HFE principles continue to be considered reactively through retrofit rather than proactively in upstream design. We recommend that performance-based HFE requirements be integrated directly into ambulance design standards.

Effects of one-pedal automobile operation on the driver's emotional state and cognitive workload.

A one-pedal system for operating an electric vehicle allows drivers to flexibly accelerate and decelerate (and even stop) by using just an accelerator pedal. Based on previous findings, one-pedal operation is considered to have the potential to increase positive emotions and decrease cognitive workload. To test this possibility, the present study compared the emotional state and cognitive workload between one-pedal and conventional two-pedal operation. Participants drove a vehicle on public roads, and driving enjoyment (i.e., pleasure and immersion) and the cognitive workload (i.e., ease and effortlessness) were assessed by means of questionnaires. In addition, physiological variations associated with driving pleasure and difficulty were assessed by electroencephalography (EEG). Both the questionnaire and EEG results revealed an increase in driving enjoyment in one-pedal operation. On the other hand, only the EEG results suggested a decrease in the cognitive workload in one-pedal operation; the questionnaire results did not show a significant difference between the pedal conditions. These findings support the notion that one-pedal operation has a positive influence on the driver's mental state, though its influence on the cognitive workload will require further investigation. We discuss future directions toward a better understanding of the effects of one-pedal operation on the driver's mental state.

The effect of aircraft seat pitch on comfort.

This study explores the relationship between seat pitch and comfort, and the influencing factors, like space experience and anthropometric measurements. Two hundred ninety-four participants experienced economy class seats in a Boeing 737 with 28-inch, 30-inch, 32-inch and 34-inch seat pitches. Anthropometric measurements of the participants were measured. Participants completed a questionnaire on comfort (10-scale), discomfort (CP-50) and space experience and the results were analysed using SPSS 25. This study showed a significant relationship between seat pitch and comfort as well as discomfort. Additionally, it was found that the mean rank of discomfort of each pitch size for the middle seat was higher than the window and aisle seat, though seat pitch did affect the (dis)comfort more compared with seat location. It was also found that anthropometric sizes significantly affect the (dis)comfort on smaller pitch sizes, and all space experience questions had a correlation to the pitch sizes.

Difference thresholds for a vehicle on a 4-poster test rig.

Improving vibration-induced discomfort often requires a reduction in the vibration experienced by vehicle occupants. Simulation software and test equipment are able to measure changes in vibration that are too small for humans to perceive. It is therefore important to know how large the change in vibration should be, i.e. the difference threshold, for occupants to perceive an improvement in comfort. This study estimates difference thresholds for ten automotive engineers seated in a vehicle on a 4-poster test rig. Participants were exposed to multi-axis vibration. Component ride values were calculated by applying BS 6841 frequency weightings and multiplication factors to seat accelerations in the six directions. Difference thresholds were estimated for two road profiles using the vertical component ride value and combined point ride value (i.e. the root-sums-of-squares of the six component ride values). The two road profiles had different magnitudes, but the same spectral shape, resulting in median vertical component ride values of 0.58 and 1.01 m.s.-2, root-mean-square. An up-down transformed response rule was used with a three-down-one-up response grouping to estimate difference thresholds at a 79.4% probability level. The median relative difference threshold for the two roads was 10.13% and 8.58% considering the vertical component ride value, and 10.99% and 9.24% considering the combined point ride value. No statistically significant difference was found between the medians of the relative difference threshold over the two roads considering either of the two ride values (p-value = 0.995 in both instances), suggesting that Weber's law holds.

Self-reported impact of respirator use on health care worker ability to perform patient care.

In a study of 1,152 health care workers surveyed prior to the COVID-19 pandemic, most disagreed that respiratory protective equipment use interferes with patient care but reported that it would affect respirator use compliance if it did. A patient's fear reaction variably influenced self-reported health care worker compliance with respirator use. Strategies to improve protective equipment design may remove potential barriers to respirator use and allow better health care worker-patient relationships.

A mother-centered evaluation of breast pumps.

Existing literature outlines mothers' negative experiences with breast pumps, yet a gap exists of which breast pump characteristics are important to mothers. Identifying which breast pump characteristics are important to breast pumping mothers, and any variation between mothers who do or do not work outside of the home, will help identify user needs. A survey collected information on mothers' experiences with breast pumps and impressions of their characteristics. Latent Class Analysis (LCA) was used to determine whether there were possible groupings of impressions of these characteristics. The LCA identified a two-class model with mothers' age as a significant covariate. Portability, ease of use, low-weight, fast milk extraction, comfortability, low-noise, and discreet were all found to be important to one group of mothers, while only portability, ease of use, fast milk extraction, and comfortability were found to be important to another group of mothers. Mothers' work status was not a significant covariate but did predict class membership when considered as a grouping variable in conjunction with age. Breast pumping mothers' needs were found to differ based on their work status and age together, and collecting and considering these different needs is vital to creating redesigns that improve mothers' breast pumping experience.

Automated driving: A biomechanical approach for sleeping positions.

Occupants of autonomous vehicle have frequently indicated the desire to sleep or rest while driving, yet little has been known regarding the suitable design criteria for a biomechanically reasoned in-vehicle sleeping position. This study was aimed at evaluating the biomechanical quality of different backrest and seat pan angle combinations, and at predicting the most favourable sleeping positions based on vehicle restriction. More specifically, the interface pressure distribution and subjective suitability rating of 23 subjects was assessed in a total of nine (3 × 3) combinations of seat pan (20°, 30°, 40°) and backrest (145°, 155°, 165°) angles. Biomechanical quality was evaluated with an interface pressure score (IPS) based on sensitivity weighted pressures and the total contact area. Two-way repeated measures ANOVA revealed that IPS significantly improves with increasing seat pan angle whereas backrest angles of 155° or 165° lead to significant better IPS compared to flatter ones (145°). The overall highest IPS was observed for a 40°-seat pan angle in combination with a 155°-backrest angle. Subjective suitability rating revealed that people prefer a combination of 165° backrest angle with a seat pan of 20°; however, eight of nine combinations can be considered as suitable for sleeping. Therefore, the combination of a 40°-seat pan angle and 155° backrest is recommended by the present study for an in-vehicle sleeping position due to the increased biomechanical quality.

Effect of material property, surface temperature and contact duration on the thermal sensation when contacting shell materials of electronic devices.

Heat generated in electronic devices is generally unevenly distributed across the casing. Contacting the hot areas may cause thermal discomfort and possibly skin burn. This study aims at better understanding the interrelationship between the thermal sensation, material properties and surface temperature for enhancing the user experience of electronic devices. A Thermal Simulation System was developed in this study to precisely control the surface temperature of shell materials to simulate various end-use conditions. Seventeen participants were asked to contact the plates with their fingers and rate their thermal sensation using the magnitude estimation approach. Results showed that thermal sensation magnitude and plate temperature followed a power function. The differences in sensation magnitude can be attributed to the thermal inertias of different materials. The findings suggested that laminated plate was generally perceived cooler when heated. Given that the surface temperature of plate is higher than skin, the thermal sensation magnitude increases with contact duration.

Emotional factors and physical properties of ballpoint pens that affect user satisfaction: Implications for pen and stylus design.

Many studies of ballpoint pens have been conducted. However, those studies have not considered the emotional factors that can enhance user experience. Styluses resemble ballpoint pens in many ways, which are widely available in a variety of styles. Therefore, in the present study, we explored the physical and emotional attributes that improve user satisfaction with typical ballpoint pens, with the goal of also understanding what factors might be important for stylus design. First, 14 emotional factors associated with the pens were derived. Second, 16 different types of ball-point pens were measured for six physical properties. Then, an experiment was performed to assess user satisfaction and emotional factors for pens. The House of Quality (HOQ) was used to obtain the chief physical properties. Results showed that to increase user satisfaction it is necessary to make pens be comfortable, fine, refined, deep, and natural. Also, we found that for high user satisfaction pens need to be heavier and longer, have thick and antislip grips and thin nibs, and their center of gravity should be located close to the nib to increase user satisfaction.

Design Drives Discovery in Causal Learning.

We assessed whether an artifact's design can facilitate recognition of abstract causal rules. In Experiment 1, 152 three-year-olds were presented with evidence consistent with a relational rule (i.e., pairs of same or different blocks activated a machine) using two differently designed machines. In the standard-design condition, blocks were placed on top of the machine; in the relational-design condition, blocks were placed into openings on either side. In Experiment 2, we assessed whether this design cue could facilitate adults' (N = 102) inference of a distinct conjunctive cause (i.e., that two blocks together activate the machine). Results of both experiments demonstrated that causal inference is sensitive to an artifact's design: Participants in the relational-design conditions were more likely to infer rules that were a priori unlikely. Our findings suggest that reasoning failures may result from difficulty generating the relevant rules as cognitive hypotheses but that artifact design aids causal inference. These findings have clear implications for creating intuitive learning environments.

Human factors considerations in designing a personalized mobile dialysis device: An interview study.

Recent technical advances have enabled the creation of mobile dialysis device prototypes. These prototypes have been tested for their ability to allow an individual to be dialyzed continuously rather than sporadically. The most recent prototype of a mobile dialysis device aims at increased functionality, which suggests that human factors issues (e.g., efficiency, bulkiness, and weight) are now considered carefully. This study describes advances in the design of an Ambulatory Kidney to Improve Vitality (AKTIV), using an interview protocol during the early stages of product development to capture patients' and caregivers' reactions. The AKTIV has the potential to improve patients' quality of life and decrease mortality rates. The goal of our study is to examine patients' and caregivers' design preferences and feature considerations for an AKTIV. We interviewed 22 participants (age M = 57.50, SD = 13.30), of whom 12 were female and 16 were patients. A pre-interview survey was distributed to the participants, and semi-structured interviews were subsequently held. The pre-interview results show that the belt and backpack designs were preferred over the shoulder bag and distributed designs. The participants also indicated on their pre-interview forms that safety and accuracy were more important to them than attachment ease, comfort, compactness, or operational simplicity. Invisibility and mobility were frequently mentioned when determining the strengths of each of the five design types during the interviews. Finally, individual differences in preferences for the various design types and attributes were identified. The results from our study have important implications for improving efficiency, effectiveness, and user satisfaction in relation to AKTIV prototypes and products. The findings from this interview study will help to ensure engineers and clinicians have target parameters for redesigning the AKTIV.

I want to brake free: The effect of connected vehicle features on driver behaviour, usability and acceptance.

This study evaluated the effectiveness and acceptance of four connected vehicle features, i.e. Emergency Electronic Brake Lights (EEBL), Emergency Vehicle Warning (EVW), Roadworks warning (RWW) and Traffic Condition Warning (TCW) which were presented via a mobile phone mounted near the line of sight. A driving simulator study was conducted in which 36 drivers were exposed to different levels of urgent and critical situations. They involved the approach of an emergency vehicle, an emergency braking of a lead vehicle, a roadworks area and a congested section of a road. All these events took place in a simulated motorway scenario. In the EEBL event, the vehicle braking ahead with the brake lights on was either visible or not (between-subjects). Whereas no effect of RWW and TCW were observed on driving behaviour, results showed that drivers who were shown the EEBL warnings had shorter braking and decelerating response times, and a slower mean speed during the events, and this was independent of brake lights visibility. The EVW resulted in participants giving way to the emergency vehicle (i.e. staying on the slow lane instead of overtaking slower vehicles) more frequently than those who did not receive the warning. The mobile phone app was accepted and considered usable. Locating the mobile phone in different locations within the drivers' line of sight (i.e. dashboard, instrument cluster) did not impact significantly neither drivers' attitudes nor behaviour. Additional in-vehicle information systems could enhance safety and allow emergency vehicles to get faster to their destination.

Preference ranking test for different icon design formats for smart living room and bathroom functions.

The current study illustrates the icon design process for 20 functions for a smart living room and smart bathroom of a commercial smart building control system. For each function name, seven icon formats (image-related, concept-related, semi-abstract, arbitrary, word, abbreviation, and combined) were developed by 30 graduate students and compared with a preference ranking test by another 13 executive MBA students. The results indicated that the combined, image-related, concept-related, semi-abstract, word, and abbreviation each had nine, four, three, two, one and one function names ranked as the most preferred format, respectively. Since all the design formats except the arbitrary format were ranked as the most preferred at least once, it is worthwhile to generate seven icon formats for a given function and chose the most preferred based on the ranking test result. The participatory design and ranking test evaluation approach can be applied for the design and evaluation of visual icons in other application contexts.

Determining the validity of the visual field principle for designing control/display arrangements.

The Visual Field (VF) principle has been found to apply in many situations, but has not been tested under many possible conditions of operator posture with different display and control locations. In this research we used four display locations, four control locations relative to a seated operator and tested the strength of population stereotype for six different types of controls with linear displays moving either horizontally or vertically and circular displays with a neutral indicator at the 12, 3, 6 and 9 o'clock positions. Apart from several minor differences in operator responses, the VF principle held up well under all these different display/control relationships. By designing the display/control arrangement to have high stereotype strength, the direction of control movement for a given direction of indicator movement can be selected to comply with the VF principle for producing fewest errors in movement direction.

Feel the noise: Mid-air ultrasound haptics as a novel human-vehicle interaction paradigm.

Focussed ultrasound can be used to create the sensation of touch in mid-air. Combined with gestures, this can provide haptic feedback to guide users, thereby overcoming the lack of agency associated with pure gestural interfaces, and reducing the need for vision - it is therefore particularly apropos of the driving domain. In a counter-balanced 2 × 2 driving simulator study, a traditional in-vehicle touchscreen was compared with a virtual mid-air gestural interface, both with and without ultrasound haptics. Forty-eight experienced drivers (28 male, 20 female) undertook representative in-vehicle tasks - discrete target selections and continuous slider-bar manipulations - whilst driving. Results show that haptifying gestures with ultrasound was particularly effective in reducing visual demand (number of long glances and mean off-road glance time), and increasing performance (shortest interaction times, highest number of correct responses and least 'overshoots') associated with continuous tasks. In contrast, for discrete, target-selections, the touchscreen enabled the highest accuracy and quickest responses, particularly when combined with haptic feedback to guide interactions, although this also increased visual demand. Subjectively, the gesture interfaces invited higher ratings of arousal compared to the more familiar touch-surface technology, and participants indicated the lowest levels of workload (highest performance, lowest frustration) associated with the gesture-haptics interface. In addition, gestures were preferred by participants for continuous tasks. The study shows practical utility and clear potential for the use of haptified gestures in the automotive domain.