Effects of stress and effort on self-rated reports in experimental study of design activities

This paper investigates the relationships between subjective rating measure and physiological measure of mental stress and mental effort during design activities. Mental stress and mental effort were captured by skin conductance and EEG beta2 power (20–30 Hz) whereas self-rated mental stress and self-rated mental effort were obtained using the NASA Task Load Index. A strong association between self-rated effort and EEG beta2 power was found in several design tasks. The analysis shows that self-rating is by itself a mental activity which may be affected by psychological stress and may be influenced by the amount of cognitive effort allocated. Researchers who rely on subjective rating should take into account the stress and effort of respondents during the rating activities to ensure the validity of the self-report measures. The study also demonstrated that design tasks induced mental stress that continued to stay above the baseline even after the tasks were completed.     

基于自然接触传感器的智能控制手柄

研究开发了一种用于控制手柄的自然接触传感器组.该传感器组能够实时地测量皮肤血流容积、皮肤导电性、皮肤温度和握力等人体生理信号,同时不会改变和打扰人原来的工作状态.传感器的设计是基于自然接触理念,通过包覆的方式安置到控制手柄上,以保证人和传感器的自然接触,包覆有此类传感器的手柄称为智能控制手柄,实验结果显示智能控制手柄具...     

Reducing back stress to nursing personnel: an ergonomic intervention in a nursing home

A prospective epidemiologic study was conducted in two units (140 beds and 57 nursing assistants) of a nursing home to demonstrate the efficacy of an ergonomic intervention strategy to reduce back stress to nursing personnel. The total programme involved the following: determining patient handling tasks perceived to be most stressful by the nursing assistants (NAs); performing an ergonomic evaluation of these tasks; and conducting a laboratory study to select patient transferring devices perceived to produce less physical stress than existing manual patient-handling methods. The intervention phase included training NAs in the use of these devices, modifying toilets and shower rooms, and applying techniques to patient care. Immediately after completing the intervention programme, a post-intervention analysis (which lasted eight months in unit 1 and four months in unit 2) was performed.

A biomechanical evaluation of the physical demands required to perform stressful patient-handling tasks showed that the mean compressive force on the L5/S1 disc, the mean hand force required to make a transfer, and the strength requirements (expressed as percentage female population capable) were 1964?N, 122?N, and 83% after intervention as compared to 4751?N, 312?N, and 41% before intervention. Subjectively, the mean rating of perceived exertion was less than ‘very light’ after intervention as compared to between ‘somewhat hard’ and ‘hard’ before intervention. Overall, the mean acceptability rates for the walking belt and the mechanical hoist were 81% and 87% for patient transfers. The incidence rate for back injuries prior to the intervention, 83 per 200 000 work-hours, decreased to 47 per 200 000 work-hours after the intervention. There were no injuries resulting in lost or restricted work days during the last four months of the post-intervention. It is concluded that an appropriate ergonomic intervention programme offers great promise in reducing physical stress and risk of low-back pain to nursing personnel. However, large-scale studies in different nursing homes are needed to confirm the above findings.     

Effects of virtual environment platforms on emotional responses

The goal of the current study was to investigate the effects of different virtual environment (VE) technologies (i.e., desktop, head mounted display, or fully immersive platforms) on emotional arousal and task performance. Fifty-three participants were recruited from a college population. Reactivity to stressful VEs was examined in three VE systems from desktop to high-end fully immersive systems. The experiment was a 3 (desktop system, head mounted display, and six wall system) × 2 (high- and low-stressful VE) within subject design, with self-reported emotional arousal and valence, skin conductance, task performance, presence, and simulator sickness examined as dependent variables. Replicating previous studies, the fully immersive system induced the highest sense of presence and the head mounted display system elicited the highest amount of simulator sickness. Extending previous studies, the results demonstrated that VE platforms were associated with different patterns in emotional responses and task performance. Our findings suggest that different VE systems may be appropriate for different scientific purposes when studying stress reactivity using emotionally evocative tasks.     

Heat stress and bulkiness of chemical protective clothing impair performance of medical personnel in basic lifesaving tasks

The study examined the impact of chemical protective (CP) clothing on the performance of lifesaving tasks in thermoneutral and cold conditions. Eleven males performed pre-exercise followed by lifesaving tasks wearing either field combat uniform at 21 degrees C (U) or CP clothing at 21 degrees C (CPN) and -5 degrees C (CPC). The tasks were ventilating a doll (VA) and connecting an intravenous line (IV). Mean skin temperature was significantly higher for CPN compared to U and CPC during pre-exercise, VA and IV. Changes in blood pressure were significantly greater with CP clothing than without during VA and IV. The number of breaths per min (in VA) and time needed for IV increased by 19% (p < 0.05) and 18%, respectively, for CPN compared to U. Due to the cold, the additional increment was 5% and 17%, respectively, for CPC. Wearing of CP clothing in thermoneutral or in cold conditions may not prevent but, especially in the cold, significantly impede the performance of basic medical tasks. The findings of this study showed that performing medical tasks while wearing nuclear, biological and chemical protective clothing is impaired due to significant changes in physiological strain. This suggests that realistic training in local conditions as well as in cold conditions is needed to realise the restrictions due to protective clothing.     

Towards affective camera control in games

Information about interactive virtual environments, such as games, is perceived by users through a virtual camera. While most interactive applications let users control the camera, in complex navigation tasks within 3D environments users often get frustrated with the interaction. In this paper, we propose inclusion of camera control as a vital component of affective adaptive interaction in games. We investigate the impact of camera viewpoints on psychophysiology of players through preference surveys collected from a test game. Data is collected from players of a 3D prey/predator game in which player experience is directly linked to camera settings. Computational models of discrete affective states of fun, challenge, boredom, frustration, excitement, anxiety and relaxation are built on biosignal (heart rate, blood volume pulse and skin conductance) features to predict the pairwise self-reported emotional preferences of the players. For this purpose, automatic feature selection and neuro-evolutionary preference learning are combined providing highly accurate affective models. The performance of the artificial neural network models on unseen data reveals accuracies of above 80% for the majority of discrete affective states examined. The generality of the obtained models is tested in different test-bed game environments and the use of the generated models for creating adaptive affect-driven camera control in games is discussed.     

Autonomic nervous system and subjective ratings of strain in air-traffic control

The paper is aimed at studying the perceived strain in professional air-traffic controllers both through self-evaluation and physiological indicators from the autonomic nervous system (ANS). The number of aircraft to be monitored was the main independent variable and could evolve at random within 1 and 10. Five ANS variables were recorded continuously in 25 participants while they handled real traffic: skin potential, skin conductance, skin blood flow, skin temperature and instantaneous heart rate. The tonic level of each physiological variable was averaged to match the times spent monitoring a constant number of aircraft. After the session, participants reacted in compliance with the NASA-TLX rating scale. Subjective ratings and physiological values were closely correlated to the number of aircraft, especially when data were standardized thus reducing inter-subjects differences in baseline levels. Results provide objective information to prevent air-traffic controllers from overloaded situations as well as to improve passengers’ safety.     

Heat stress and bulkiness of chemical protective clothing impair performance of medical personnel in basic lifesaving tasks

The study examined the impact of chemical protective (CP) clothing on the performance of lifesaving tasks in thermoneutral and cold conditions. Eleven males performed pre-exercise followed by lifesaving tasks wearing either field combat uniform at 21°C (U) or CP clothing at 21°C (CPN) and–;5°C (CPC). The tasks were ventilating a doll (VA) and connecting an intravenous line (IV). Mean skin temperature was significantly higher for CPN compared to U and CPC during pre-exercise, VA and IV. Changes in blood pressure were significantly greater with CP clothing than without during VA and IV. The number of breaths per min (in VA) and time needed for IV increased by 19% (p < 0.05) and 18%, respectively, for CPN compared to U. Due to the cold, the additional increment was 5% and 17%, respectively, for CPC. Wearing of CP clothing in thermoneutral or in cold conditions may not prevent but, especially in the cold, significantly impede the performance of basic medical tasks. The findings of this study showed that performing medical tasks while wearing nuclear, biological and chemical protective clothing is impaired due to significant changes in physiological strain. This suggests that realistic training in local conditions as well as in cold conditions is needed to realise the restrictions due to protective clothing.     

Stress response caused by system response time when searching for information on the Internet

System response time (SRT) is suspected to be a stress-inducing factor when searching for information during human-computer interactions. In this study 26 volunteers, grouped into skilled and unskilled Internet users, completed three tasks of searching for information on the Internet, whereupon they rated their strain. Heart rate, nonspecific skin conductance responses, and skin conductance level after SRTs lasting 2, 10, and 22 s were analyzed. Results showed physiological stress responses of higher heart rates and enhanced electrodermal activity related to SRT duration, independent of expertise. For persons experiencing high strain, a higher overall heart rate and a heart rate of 114 beats per minute were observed for the 22-s condition. As no significant effect of expertise on stress response was found, this indicates that no long-term habituation took place. To avoid stress, short SRTs and/or effective coping mechanisms are recommended. The potential application of this research is the suggestion of using a fast Internet connection to reduce the stress response.     

Stress reactions to computer‐interactive tasks as a function of task structure and individual differences

The resurgence of interest in occupational stress has resulted in an emphasis on identifying work conditions that are potentially causal in generating stress reactions and psychological disorders among workers. Although a considerable knowledge base related to this topic has evolved, relatively little is known regarding the impact of computer technology on incidence of job stress. This issue is especially important for older workers, given the increased use of computers in most occupations, the aging of the workforce, and the changes in cognitive and physiological capacities that occur with increased age. The study reported in this article was concerned with developing a methodology to evaluate stress for computer‐interactive tasks as a function of the mental workload of the task and the age of the individual. Sixty‐five women ranging in age from 25 to 70 years performed three computer‐interactive tasks that varied as a function of information processing complexity and pacing requirements. The methodology encompassed physiological, subjective, and performance measures. Results indicated differences in sensitivity among the measures as a function of task and age. The data also indicated age differences in stress reactions and performance. The findings are discussed in terms of the suitability of computer tasks for older people.     

Fusion of EEG response and sentiment analysis of products review to predict customer satisfaction

This paper proposes a novel multimodal framework for rating prediction of consumer products by fusing different data sources, namely physiological signals, global reviews obtained separately for the product and its brand. The reviews posted by global viewers are retrieved and processed using Natural Language Processing (NLP) technique to compute compound score considered as global rating. Also, electroencephalogram (EEG) signals of the participants were recorded simultaneously while watching different products on computer’s screen. From EEG, valence scores in terms of product rating are obtained using self-report towards each viewed product for acquiring local rating. A higher valence score corresponds to intrinsic attractiveness of the participant towards a product. Random forest based regression techniques is used to model EEG data to build a rating prediction framework considered as local rating. Furthermore, Artificial Bee Colony (ABC) based optimization algorithm is used to boost the overall performance of the framework by fusing global and local ratings. EEG dataset of 40 participants including 25 male and 15 female is recorded while viewing 42 different products available on e-commerce website. Experiment results are encouraging and suggest that the proposed ABC optimization approach can achieve lower Root Mean Square Error (RMSE) in rating prediction as compared to individual unimodal schemes.     

Effects of different real-time feedback types on human performance in high-demanding work conditions

Experiencing stress during training is a way to prepare professionals for real-life crises. With the help of feedback tools, professionals can train to recognize and overcome negative effects of stress on task performances. This paper reports two studies that empirically examined the effect of such a feedback system. The system, based on the COgnitive Performance and Error (COPE) model, provides its users with physiological, predicted performance and predicted error-chance feedback. The first experiment focussed on creating stressful scenarios and establishing the parameters for the predictive models for the feedback system. Participants (n=9) performed fire-extinguishing tasks on a virtual ship. By altering time pressure, information uncertainty and consequences of performance, stress was induced. COPE variables were measured and models were established that predicted performance and the chances on specific errors. In the second experiment a new group of participants (n=29) carried out the same tasks while receiving eight different combinations of the three feedback types in a counterbalanced order. Performance scores improved when feedback was provided during the task. The number of errors made did not decrease. The usability score for the system with physiological feedback was significantly higher than a system without physiological feedback, unless combined with error feedback.This paper shows effects of feedback on performances and usability. To improve the effectiveness of the feedback system it is suggested to provide more in-depth tutorial sessions. Design changes are recommended that would make the feedback system more effective in improving performances.     

Effects of control-display gain and postural control method on distal pointing performance

The present study investigated the effects of different joint-based interactive methods and control-display gains on performance and usability for distant pointing by using ISO 9241–9 test procedures. Ten healthy participants performed multi-directional tapping tests with three joint-based interactive methods (wrist-, elbow-, and shoulder-based interactive methods) and three CD gains (0.6, 1.0, and 1.7) by using an air mouse as the input device. The experimental results indicated that the wrist-based interactive method is a better interactive method for tasks where pointing speed is the highest priority and the 1.7 CD gain, which was found to cause significantly higher MT and ER and lower TP and subjective usability rating scores than wrist- and elbow-based pointing, should be avoided in distal pointing tasks. Furthermore, the best suggested CD gains for the wrist-based interactive method are 1.0 and 1.7. The recommended CD gain setting of the elbow-based interactive method is 0.6, and 1.0 CD gain is feasible for the shoulder-based interactive method.     

基于rPPG的生理指标测量方法综述

远程光电容积脉搏波描记法（remote photoplethysmography,rPPG）是指通过摄像头等传感器来捕捉由心动周期造成的皮肤颜色周期性变化的技术。利用rPPG技术可以提取血液体积脉冲信号,进而测量心率、呼吸率和心跳变异性等心动周期相关的生理指标。近年基于rPPG的生理指标测量方法取得了飞速发展,准确性和鲁棒性已得到了大幅提高。该类技术的算法流程主要包括图像/视频的获取和感兴趣区域提取、血液体积脉冲信号提取和生理指标测量等步骤。基于这一算法流程,本文从算法所依据的假设或先验知识出发,对相关文献进行了总结和讨论。此外,还从评测任务、评测数据、评测指标及评测协议等4个方面系统整理针对基于rPPG的生理指标测量方法的评价体系。最后,本文讨论了该领域当前所面临的挑战并展望了可能的技术路线。     

基于生理信号的情感计算研究综述

情感计算是现代人机交互中的一个重要研究方向,旨在研究与开发能够识别、解释、处理和模拟人类情感的理论、方法与系统.脑电、心电、皮肤电等生理信号是情感计算中重要的输入信号.本文总结了近年来基于脑电等生理信号的情感计算研究所取得的进展.首先介绍情感计算的相关基础理论,不同生理信号与情感变化之间的联系,以及基于生理信号的情感计...     

Anxiety-based affective communication for implicit human-machine interaction

An implicit human-machine interaction framework that is sensitive to human anxiety is presented. The overall goal is to achieve detection and recognition of anxiety based on physiological signals. This involves building an anxiety-recognition system capable of interpreting the information contained in physiological processes to predict the probable anxiety state. Since anxiety plays an important role in various human-machine interaction tasks and can be related to task performance, the presented anxiety-recognition methods can be potentially applied to the design of advanced machines and engineering systems capable of intelligent decision-making while interacting with humans. Regression tree and fuzzy logic methodologies have been investigated for the above task. This paper presents the results of applying these two methods and discusses their comparative merits. Three human participant experiments were designed and trials were conducted with five participants. The experimental results demonstrate the feasibility of the proposed anxiety-recognition methods. To the best of our knowledge, our work is the first consolidated effort at fusing multiple physiological indices for robust, real-time detection of anxiety using pattern recognition methods such as fuzzy logic and regression trees.     

Effect of safety shoes type,lifting frequency,and ambient temperature on subject's MAWL and physiological responses

ObjectiveThe purpose of this paper is to evaluate the lifting capabilities of individuals while wearing safety shoes in a hot environment and to investigate the behavior of the physiological responses induced by the lifting process associated with those variables.MethodsIn order to achieve the objectives of this research, two sequential studies were conducted. The first part was an acclimatization and training program followed by a psychophysical experiment. Seven male workers participated in this experiment from the university. A three-way repeated measures design, with three independent variables and seven response variables, was utilized in this study. The independent variables studied in the psychophysical experiment were: 1) environmental temperature (20 and 30 °C WBGT), 2) lifting frequency (1 and 5 lifts/min), and 3) safety shoes (light-duty, medium-duty and heavy-duty). The response variables for this experiment were: 1) maximum acceptable weight of lift (MAWL), 2) heart rate, 3) aural-canal temperature, 4) muscle electromyography (EMG) of four muscle groups (biceps brachii, anterior deltoid, trapezius, and erector spinae), 5) rating of perceived exertion, 6) rating of thermal sensation and7) safety shoes discomfort rating.ResultsThe psychophysical experiment results showed that the weights selected by participants at higher levels of the independent variables were significantly less than those selected at lower levels of the independent variables. Some of the interaction effects were also significant.ConclusionThis study found evidence that – in addition to lifting frequency, which is well reported in the literature – heat stress increases the workload intensity in manual lifting tasks influencing the psychophysical selection of MAWL and the physiological responses of the human body represented in aural-canal temperature, heart rate and muscular activities. The study findings demonstrated the necessity of accounting for work environmental temperature and type of worn safety shoes, which is a safety requirement by most employers, when calculating the recommended weight limits.Practitioner summaryMost of the manual materials handling studies had investigated worker's capacity to perform lifting tasks in different environmental conditions not considering the effect of wearing safety shoes. This research fills the gap by presenting safety guidelines regarding lifting tasks in a hot environment while wearing safety shoes.     

Towards multi-modal causability with Graph Neural Networks enabling information fusion for explainable AI

AI is remarkably successful and outperforms human experts in certain tasks, even in complex domains such as medicine. Humans on the other hand are experts at multi-modal thinking and can embed new inputs almost instantly into a conceptual knowledge space shaped by experience. In many fields the aim is to build systems capable of explaining themselves, engaging in interactive what-if questions. Such questions, called counterfactuals, are becoming important in the rising field of explainable AI (xAI). Our central hypothesis is that using conceptual knowledge as a guiding model of reality will help to train more explainable, more robust and less biased machine learning models, ideally able to learn from fewer data. One important aspect in the medical domain is that various modalities contribute to one single result. Our main question is “How can we construct a multi-modal feature representation space (spanning images, text, genomics data) using knowledge bases as an initial connector for the development of novel explanation interface techniques?”. In this paper we argue for using Graph Neural Networks as a method-of-choice, enabling information fusion for multi-modal causability (causability – not to confuse with causality – is the measurable extent to which an explanation to a human expert achieves a specified level of causal understanding). The aim of this paper is to motivate the international xAI community to further work into the fields of multi-modal embeddings and interactive explainability, to lay the foundations for effective future human–AI interfaces. We emphasize that Graph Neural Networks play a major role for multi-modal causability, since causal links between features can be defined directly using graph structures.     

面向沉浸式流场可视化的多视图数据管理方法

由于沉浸式环境下的三维交互方式对二维界面操作不够友好,使得依赖于二维列表界面的流场数据管理任务变得复杂且低效。为了实现沉浸式虚拟环境下对流场数据高效的组织和管理,增强用户对流场空间信息的理解,提出一种基于多视图结合交互的沉浸式流场可视化数据块管理方法。该方法构建了一个三维小视图用于提供场景概览,并通过“主视图交互+小视图辅助“”小视图交互+主视图反馈”等多种多视图组合交互方式完成对多块流场数据的管理交互操作。最后构建了一个基于手势的沉浸式流场可视化系统,定义多项交互任务,从学习时长、完成时间和用户反馈几个方面对比了多视图方法和传统交互方法差异。实验结果表明,相比于传统交互方法,多视图方法可以显著提高数据管理任务的效率。