A Vehicle Simulation Study Examining the Effects of System Interface Design Elements on Performance in Different Vibration Environments Below 3 Hz.

OBJECTIVE: This study aimed to explore the relationship between system interface elements' design features and interaction performance in simulated vehicle vibration environments. BACKGROUND: Touch screens have been widely used in vehicle information systems, but few studies have focused on the decline of touchscreen interaction performance and task load increase when driving on unpaved roads. METHOD: The interaction performance (reaction time and task accuracy rate) with vibration frequencies below 3 Hz (1.5, 2.0, and 2.5 Hz) and different interface design elements was investigated employing a touch screen computer and E-prime software. RESULTS: The results indicate that vehicle vibration (below 3 Hz) can significantly reduce interaction performance with a vehicle information system interface. CONCLUSION: An appropriate increase in the physical size of the interface design features (visual stimulus materials and touch buttons) can help to mitigate this negative effect of vibration. APPLICATION: The results and findings of this study can be utilized for the design of information system interfaces as it relates to the vibration scenario of unpaved roads.

Hand Posture and Force Estimation Using Surface Electromyography and an Artificial Neural Network.

OBJECTIVE: The purpose of this study was to develop an approach to predict hand posture (pinch versus grip) and grasp force using forearm surface electromyography (sEMG) and artificial neural networks (ANNs) during tasks that varied repetition rate and duty cycle. BACKGROUND: Prior studies have used electromyography with machine learning models to predict grip force but relatively few studies have assessed whether both hand posture and force can be predicted, particularly at varying levels of duty cycle and repetition rate. METHOD: Fourteen individuals participated in this experiment. sEMG data for five forearm muscles and force output data were collected. Calibration data (25, 50, 75, 100% of maximum voluntary contraction (MVC)) were used to train ANN models to predict hand posture (pinch versus grip) and force magnitude while performing tasks that varied load, repetition rate, and duty cycle. RESULTS: Across all participants, overall hand posture prediction accuracy was 79% (0.79 ± .08), whereas overall hand force prediction accuracy was 73% (0.73 ± .09). Accuracy ranged between 0.65 and 0.93 based on varying repetition rate and duty cycle. CONCLUSION: Hand posture and force prediction were possible using sEMG and ANNs, though there were important differences in the accuracy of predictions based on task characteristics including duty cycle and repetition rate. APPLICATION: The results of this study could be applied to the development of a dosimeter used for distal upper extremity biomechanical exposure measurement, risk assessment, job (re)design, and return to work programs.

Investigating the Overall Experience of Wearable Robots during Prototype-Stage Testing.

Wearable robots (WRs) might interact with humans in a similar manner to teammates to accomplish specific tasks together. However, the available data on WR user experience (UX) studies are limited, especially during the prototyping phase. Therefore, this study aims to examine the overall experience of WRs during the prototyping phase based on an exploratory research model. This theoretical model considered usability, hedonic quality, and attitude toward using WRs as key factors in explaining and predicting overall experience. To test the hypotheses inherent in the research model, quantitative empirical research was conducted and the data were analyzed by partial least squares structural equation modeling (PLS-SEM). The results from the PLS-SEM analysis revealed the significance level of correlations between the latent variables in the research model. The exploratory research model was able to explain up to 53.2% of the variance in the overall experience of using WRs, indicating medium predictive power. This research develops a new quantitative empirical research model that can be used to explain and predict the overall experience of interactive products such as WRs. Meanwhile, the model is needed during WR testing in the prototype phase.

Color Design Decisions for Ceramic Products Based on Quantification of Perceptual Characteristics.

The appearance characteristics of ceramic color are an important factor in determining the user's aesthetic perception of the product. Given the problem that ceramic color varies and the user's visual sensory evaluation of color is highly subjective and uncertain, a method of quantifying ceramic color characteristics based on the Back Propagation (BP) neural network algorithm is proposed. The semantic difference method and statistical method were used to obtain quantified data from ceramic color perceptual semantic features and were combined with a neural network to study the association between ceramic color features and user perceptual-cognitive evaluation. A BP neural network was used to build a ceramic color perceptual semantic mapping model, using color semantic quantified values as the input layer, color L, A, and B component values as the output layer, and model training to predict the sample. The output color L, A, and B components are used as the input layer and the color scheme was designed. The above method can effectively solve the mapping problem between the appearance characteristics of ceramic color and perceptual semantics and provide a decision basis for ceramic product color design. The case application of color design of daily-use ceramic products was conducted to verify the effectiveness and feasibility of the quantitative research method of ceramic color imagery.

Effects of variations in the tragus expansion angle on physical comfort for in-ear wearables.

Tragus expansion angle (TEA) is an angular variable that quantifies the outward degree of expansion of the tragus cartilage induced by in-ear wearables (designed with hard materials) fitted into the external ear. It is a physical factor that directly influence user's comfort experience during interaction with in-ear wearables. This study was aimed at quantifying the effects of variations in TEA on physical comfort. TEA was measured and normalised employing a measuring device and Tragus Expansion Index (TEI) proposed in this study. Physical (dis)comfort was assessed using a rating scale designed based on the 5-point Likert and Borg-CR10 scales. Comparatively, the comfort range of variations in TEA was similar for both genders. Males could endure a higher level of variations in TEA compared to females. A quantitative relationship between variations in TEA and (dis)comfort ratings was established using TEI values and GaussAmp function, which can be employed for ergonomic design purposes. Practitioner summary: This study provides an empirical and available source for quantifying the effects of variations in the tragus expansion angle on physical comfort, including quantitative tools and (dis)comfort rating models, which could be used as a reference for improving the fit, comfort and functional capacity of in-ear wearable devices.

Analysis of the external acoustic meatus for ergonomic design: part I - measurement of the external acoustic meatus using casting, scanning and rapid estimation approaches.

Numerous ear-related wearables require precise measurements of the external acoustic meatus (EAM) to optimise function and comfort. The purpose of this study is to describe a novel methodology for measuring the EAM. A total of 23 measurement variables (18 novel) of the EAM from the entrance to the second bend were collected on 700 Chinese subjects (age: 15-83) using casting and 3D scanning over seven age spans: 10, 20, 30, 40, 50, 60 s and 70+. The ear horizontal plane was identified as a new reference plane for measurements and the medial concha was selected as the reference point for positioning the entrance. A detailed approach to characterising the EAM was developed as was an approach for the rapid estimation of circumference and area using regression equations making it ideal for use in early design conceptualizations. Practitioner summary: This study provides a scalable measurement methodology for determining anthropometric measurements of the external acoustic meatus. The measurement methodology and its application to the design and fitting of ear-related wearables are important to optimising their function and comfort.

Analysis of the external acoustic meatus for ergonomic design: part II - anthropometric variations of the external acoustic meatus by sex, age and side in Chinese population.

For devices worn inside the ear, detailed anthropometric data of the external acoustic meatus (EAM) is needed, yet lacking due to the complex and costly methodology associated with attaining such measurements. The purpose of this study was to provide the anthropometric characteristics of the EAM including variations by age group, sex, and side (right/left). 1400 external ears (700 Chinese subjects) were casted and scanned. A total of 23 EAM dimensions of length, width, angle, circumference and area were measured, most of which changed by age group, sex and side. 19 measurements were larger in males and 17 measurements were larger in left-side ears. Except the entrance length and circumference, measurements were not statistically significant between left- and right-side ears. This study provides key anthropometric measurements of the EAM in a Chinese population which can be used for ergonomic design purposes. Practitioner summary: This study provides an available source for anthropometric variations of the external acoustic meatus by age, gender and side in the Chinese population, which can be used as a reference to improve the fit, comfort and function of in-ear wearable devices.

Effects of the Level of Interactivity of a Social Robot and the Response of the Augmented Reality Display in Contextual Interactions of People with Dementia.

The well-being of people with dementia (PWD) living in long-term care facilities is hindered due to disengagement and social isolation. Animal-like social robots are increasingly used in dementia care as they can provide companionship and engage PWD in meaningful activities. While most previous human-robot interaction (HRI) research studied engagement independent from the context, recent findings indicate that the context of HRI sessions has an impact on user engagement. This study aims to explore the effects of contextual interactions between PWD and a social robot embedded in the augmented responsive environment. Three experimental conditions were compared: reactive context-enhanced robot interaction; dynamic context-enhanced interaction with a static robot; a control condition with only the dynamic context presented. Effectiveness evaluations were performed with 16 participants using four observational rating scales on observed engagement, affective states, and apathy related behaviors. Findings suggested that the higher level of interactivity of a social robot and the interactive contextualized feedback helped capture and maintain users' attention during engagement; however, it did not significantly improve their positive affective states. Additionally, the presence of either a static or a proactive robot reduced apathy-related behaviors by facilitating purposeful activities, thus, motivating behavioral engagement.

Quantification of lower extremity physical exposures in various combinations of sit/stand time duration associated with sit-stand workstation.

BACKGROUND: Sit-stand workstations are available for office work purposes but there is a dearth of quantitative evidence to state benefits for lower limb outcomes while using them. And there are no guidelines on what constitutes appropriate sit/stand time duration. The primary aim of this study has been to compare muscle activity and perceived discomfort in the lower extremity during various combinations of sit/stand time duration associated with a sit-stand workstation separately and to evaluate the effects of the sit-stand workstation on the lower extremity during the text entry task. MATERIAL AND METHODS: During the 5 days, all participants completed a 2-h text entry task each day for various sit/stand time duration combinations as follows: 5/25 min, 10/20 min, 15/15 min, 20/10 min, 25/5 min. Lower extremity muscular exposure of 12 male and 13 female participants was collected at 8 sites by surface electromyography and body discomfort was calculated by a questionnaire under those 5 conditions. RESULTS: Results have demonstrated that lower extremity muscle activity has been significantly varied among the 5 sit/stand time duration groups. Perceived level of discomfort (PLD) has not differed significantly for 9 out of 10 body parts. CONCLUSIONS: The muscle activity of the thigh region was influenced by sit/stand time duration significantly. Ergonomic exposures of lower extremity when using a sit-stand workstation were increased, particularly during the long time standing posture. Results indicate that body mass index (BMI) and gender were not significant factors in this study. Combination of sit/stand time duration 25/5 min appears to show positive effects on relief of muscle exposure of back of thigh in the shifts of sitting and standing work position. Med Pr 2017;68(3):315-327.

A comprehensive assessment of environmental factors in aircraft cockpit based on fuzzy evaluation.

BACKGROUND: The cockpit of an aircraft is the main place where the pilot controls the aircraft on a mission. An excellent cockpit environment not only ensures the pilot's basic survival needs but also improves the comfort level and alleviates fatigue when performing missions. OBJECTIVE: On the basis of domestic and international airworthiness standards, a top-down refinement method is deployed to determine the initial goal, and the environmental criteria are fully discussed and balanced in a dynamic process to build a comprehensive evaluation system for environmental factors in the aircraft cockpit. METHODS: Based on the fuzzy comprehensive evaluation theory, an evaluation model for environmental factors is constructed by combining analytic hierarchical analysis (AHP) and particle swarm optimization (PSO). Then the feasibility of the evaluation model is verified by an illustrative example. RESULTS: The results suggest that the light environment gains the highest score among the 4 environmental criteria followed by the thermal environment, while both sound environment and microenvironment have relatively low scores. CONCLUSION: As for the 27 environmental sub-criteria, temperature, illumination, lighting clarity, light-color coordination, noise duration and pressure score the highest. The evaluation findings can provide important environmental control criteria for the subsequent environmental control system in the cockpit of the aircraft.

Time-Dependent Effects of Altered Prebedtime Light Exposure in Enclosed Spaces on Sleep Performance Associated with Human States.

Purpose: Exposure to artificial light influences human performance, which is essential for maintaining healthy work and sleep. However, existing research has not explored the intrinsic links between sleep performance and human states over time under prebedtime light exposure interventions (LEIs). Methods: To investigate the time-dependent effects of altered prebedtime light exposure, four LEI groupings (#L1 - #L4) and a Time factor (D8, D9, and D10) were chosen for sleep experiments in enclosed spaces. Forty-eight young adults recruited were available for data analysis. Subjective alertness (SA), negative affect (NA), subjective sleep, and objective sleep were measured via the Karolinska Sleepiness Scale, Positive and Negative Affect Schedule, Next-day Self-assessment Sleep Quality, and joint assessment of wrist actigraphy and sleep diaries, respectively. Statistical analysis was used for the effects of light exposure on the human states (corresponding to the SA and NA) and sleep performance, while the process model helped construct the associations between the two. Results: The statistical effects revealed that the Time had a significant main effect on subjective sleep and changes in prebedtime alertness; the LEI had a significant main effect only on sleep onset latency (SOL). After undergoing altered prebedtime light exposure, the mean SA increased at prebedtime of D9 (p = 0.022) and D10 (p = 0.044); No significant effect on the NA was observed; Mean subjective sleep had a significant increase from D8 to D10. Moreover, five actigraphy-estimated sleep parameters were interrelated. In light of this, a chained pathway relationship was identified. The SOL played a mediating predictor between prebedtime state and objective sleep, which was linked to the awakening state through subjective sleep. Conclusion: Our study suggests that time-dependent effects of altered prebedtime light exposure on sleep performance are associated with human states at prebedtime and awakening, with implications for its prediction of sleep health.

Scaling-law mechanical marker for liver fibrosis diagnosis and drug screening through machine learning.

Studies of cell and tissue mechanics have shown that significant changes in cell and tissue mechanics during lesions and cancers are observed, which provides new mechanical markers for disease diagnosis based on machine learning. However, due to the lack of effective mechanic markers, only elastic modulus and iconographic features are currently used as markers, which greatly limits the application of cell and tissue mechanics in disease diagnosis. Here, we develop a liver pathological state classifier through a support vector machine method, based on high dimensional viscoelastic mechanical data. Accurate diagnosis and grading of hepatic fibrosis facilitates early detection and treatment and may provide an assessment tool for drug development. To this end, we used the viscoelastic parameters obtained from the analysis of creep responses of liver tissues by a self-similar hierarchical model and built a liver state classifier based on machine learning. Using this classifier, we implemented a fast classification of healthy, diseased, and mesenchymal stem cells (MSCs)-treated fibrotic live tissues, and our results showed that the classification accuracy of healthy and diseased livers can reach 0.99, and the classification accuracy of the three liver tissues mixed also reached 0.82. Finally, we provide screening methods for markers in the context of massive data as well as high-dimensional viscoelastic variables based on feature ablation for drug development and accurate grading of liver fibrosis. We propose a novel classifier that uses the dynamical mechanical variables as input markers, which can identify healthy, diseased, and post-treatment liver tissues.

Effects of aircraft tray table height and neck posture on passenger comfort: A study of the economy class cabin.

BACKGROUND: The tray table in economy class air travel may cause excessive neck flexion and discomfort in passengers. OBJECTIVE: The purpose of this study is to examine the influence of different tray table heights on the neck posture and discomfort perception of passengers. METHODS: A passenger experience survey was used to determine the passengers' view that the tray table was not high enough, and that most passengers were dissatisfied with the overall comfort evaluation of the tray table, especially passengers with obesity. Three head-neck angles and discomfort perceptions of six body parts in 58 participants were recorded by neck posture 3D scanning and perceived level of discomfort assessment, respectively. RESULTS: Tray tables at the original height (68 cm) caused unnatural neck posture and discomfort in participants. Raising the tray table can improve the neck posture of participants and reduce discomfort. However, raising the tray table too high will cause more shoulder discomfort in participants. Based on the results, 78 (±2) cm is suggested as the suitable thresholds range of tray tables for economy class air travel. CONCLUSION: The results and findings of this study could provide a theoretical base for the optimization of tray table design.

Assessing the Influencing Factors of Electronic Word-of-Mouth on CSR Issues. A Case of Hospotality Service Industry of China.

Corporate social responsibility (CSR) information can be effectively disseminated via social media in a variety of industries, including the hospitality sector. In the same way, the media has a significant impact on CSR because the news media helps companies achieve their CSR goals. Prior research has not examined the main factors that influence electronic word of mouth (eWOM) on media coverage of CSR issues via social networking websites. For the purpose of examining the most significant predictors of intention to share or comment on negative CSR news reported by one media outlet on a specific social networking site (SNS). 677 Wechat users in China were surveyed in order to test the proposed model empirically. According to the findings of the study, eWOM intentions are positively influenced by environmental CSR content, and advertisement related CSR content. It also confirmed that the value of information is positively influenced by the credibility of the source. The variables interpersonal influencer impact and privacy concerns had no significant relationship, nor did they have any significant relationship with the intentions to share and comment on Wechat. Further the study findings suggest the theoretical and managerial policy recommendation for decision makers.

A Telecommuting Experience Service Design Decision Model Based on BP Neural Network.

Introduction: The telecommuting experience and job performance have been significantly impacted by the COVID-19 pandemic, and job performance stability of telecommuting employees has become a critical concern. Objective: A decision model for telecommuting experience service design was constructed based on a backpropagation (BP) neural network to provide a theoretical basis for enterprises to evaluate telework performance and the psychological health of employees. Methods: The analytic hierarchy process (AHP) was used to determine the core stakeholders. The grey relational analysis (GRA) method and the NASA Task Load Index (NASA-TLX) scale were used to measure the factors affecting employees' telecommuting experience and job performance. A BP neural network relationship model of employees' telecommuting experience was established to predict its impact on employees' job performance. Results: Based on the model prediction results, a service system map was created, and the potential to enhance the telework performance of employees was evaluated. Discussion: It was concluded that the factors affecting the telecommuting experience were diverse, but emotions had the dominant influence. Significant positive correlations were found between emotional impact and temporal perception, execution difficulty, and communication barriers. Conclusion: The proposed decision model for telecommuting experience service design accurately predicted the impact of telecommuting efficiency, providing an effective approach for innovative remote management.

Effect of airplane passenger seat armrest height on human neck comfort when using a smartphone.

OBJECTIVES: The objective of this study was to explore the relationship between seat armrest height and human neck comfort when using a smartphone while sitting on a passenger seat during the flight. MATERIAL AND METHODS: The authors used a wireless angle-measuring instrument and subjective comfort scale to evaluate the changes of head flexion angle and neck comfort level of 24 young smartphone users in an aircraft simulated cabin. RESULTS: The study results indicated that using a smartphone while sitting on a passenger seat during the flight would pose a larger discomfort to the neck, and the discomfort would be higher for gaming than reading tasks. Seat armrest height is related to the comfort level of the neck when using a smartphone, increasing the height of the armrest can effectively alleviate discomfort in this state. CONCLUSIONS: Considering the prevalence of passengers using smartphones in aircraft, a seat armrest that can be properly adjusted in height, which can effectively reduce the risk of passenger head flexion angle and neck discomfort. Int J Occup Med Environ Health. 2022;35(2):199-208.

Analysis of the auricles and auricular shape types for ear-related wearables: A study of mainland Chinese sample aged 15-79.

BACKGROUND: Comprehension of the complex shape of the auricle and how it differs in terms of factors such as sex, age, and side have become an imperative aspect of the fabrication and service delivery of products that are natural, functional, and healthy for users. OBJECTIVE: This study was aimed at providing a clear understanding of the anthropometric characteristics based on age, sex, size, and side and shape type of the auricles of mainland Chinese samples. METHODS: Casting and 3D scanning were employed to obtain eighteen auricular measurement variables from 1120 subjects (aged 15-79). Examination of sex-related and bilateral differences were conducted. Furthermore, factor analysis was employed to establish the factors associated with the variations in auricular shape. Also, hierarchical cluster analysis was performed to classify the auricular shapes of individuals. RESULTS: The auricular inclination angle, conchal depth and tragal height did not exhibit any specific trend across the age groups. No significant bilateral difference was observed in both genders. The auricular shapes were classified into five types according to six major factors. CONCLUSIONS: It was observed that measurement variables of the Chinese auricles changed continuously with age, with most of the linear variables exhibiting a steady increase. The apparent strong association between the auricular types and age groups indicate that a person's auricular shape may change with age.

A Consensus-Reaching Approach to the Evaluation of Product Design Alternatives with Multiple Preference Structures.

With interdisciplinarity being an important characteristic of contemporary product design, the evaluation of design alternatives also involves multiple disciplines, and the evaluator group usually consists of evaluators from different fields and with obvious heterogeneous characteristics. To effectively satisfy the heterogeneous needs of evaluators and improve the credibility of evaluation results, the paper introduces a consensus-reaching approach that incorporates multiple preferences to the evaluation of product design alternatives. First, in order to obtain individual preference information, each evaluator is asked to evaluate all the design alternatives using a preference structure that he/she is familiar with. Second, we use a transfer function to uniform the evaluation information obtained from various preference structures into a complementary judgment matrix. Then, we use the Hybrid Weighted Averaging (HWA) operator weight determination model to aggregate the preference information and obtain the group preference information. Then, we measure the consensus degree between individual evaluators and the group using a consensus measurement method. After that, we use the feedback mechanism to instruct individual evaluators to modify their preferences until a consensus is achieved. We explain the application steps and the feasibility of this approach through the evaluation of the design alternatives of multichannel fluorescence immunochromatography analyzers (MFIAs).

Aircraft Passenger Comfort Based on Muscle Activation and Perceived Discomfort During Long Flights.

OBJECTIVE: The purpose of this study was to investigate the comfort of aircraft passengers during long flights and to determine the effects of the seatback angle and the seat pitch on passengers' upper body muscles (neck, shoulder, and lower back) and subjective comfort.METHODS: All subjects sat on an aircraft seat for 2 h with different levels of seatback angle and seat pitch. Subjective discomfort scores and root mean square (RMS) and mean power frequency (MPF) values were used to evaluate muscle fatigue, and all data were calculated for every 15-min interval.RESULTS: Significant increases of MPF for all three muscles were found at 30 min, along with significant increases in the perceived levels of discomfort (PLD) over 2 h. Besides, a 120° seatback angle and a 34˝ seat pitch resulted in lower PLD values for the lower back and hip areas than smaller ones (significant difference).DISCUSSION: It took around 30 min before pronounced discomfort in the upper body regions occurred during flight. The larger parameters of seatback angle and seat pitch may significantly contribute to the easing of subjective discomfort. Moreover, a decrease in MPF coupled with a concomitant increase in RMS does not appear to be a reliable indicator of discomfort rate. The need for further development of discomfort indicators which are more directly related to muscular activation is recognized.Pei H, Yu S, Ding M, Bai Z. Aircraft passenger comfort based on muscle activation and perceived discomfort during long flights. Aerosp Med Hum Perform. 2020; 91(5):416-421.

The effects of the seat cushion contour and the sitting posture on surface pressure distribution and comfort during seated work.

OBJECTIVES: The purpose of this paper is to investigate the effects of the seat cushion contour and the sitting posture on the seat pan interface pressure distribution and subjective comfort perception. MATERIAL AND METHODS: Overall, 16 volunteers typed a text passage on a laptop while seated, by assuming 3 kinds of common sitting postures (forward, relaxed and upright) in 4 seat cushion configurations: chair only, and chair with 1 of 3 supplementary cushions. Pressure data and cushion comfort ratings were collected in the experiment. RESULTS: It was found that the sitting posture and the seat cushion contour had different impacts on surface pressure. The seat cushion contour had an impact on pressure parameters and pressure distribution on the seat pan, while the sitting posture affected the location of peak pressure on the seat pan. The correlation analysis revealed that the subjective comfort rating was significantly correlated with average pressure (AP) and mean peak pressure (MPP). CONCLUSIONS: The conclusion was that the cushion contour had a greater effect on seat pan interface pressure parameters than the sitting posture. Notably, AP and MPP can be indicators for assessing seat cushion comfort in a short-term perspective. Int J Occup Med Environ Health. 2020;33(5):675-89.