On the investigation of the neurophysiological correlates of knowledge worker mental fatigue using the EEG signal

Technological trends and advances in automation have underscored the importance of task performance of certain jobs requiring mental functions such as information processing and decision analyses. Most experts agree that such work environments produce increased mental activities, with profound implications for mental fatigue and stress. Consequently, productivity measurement and improvement for white collar or ‘knowledge worker’ occupations remains a major challenge and concern. This investigation defines an experimental approach that examines the neurophysiological correlates of white collar worker mental fatigue using the EEG signal. A 6 h laboratory experiment was conducted to simulate work output. The methods of assessing fatigue employed were mental tests and physiological measurements. The experiment involved reading of standardized texts, finding solutions to arithmetic-logical problems and a combination of both task types. Two primary performance measures were obtained, work output and brain waves. Fast Fourier transform and correlation analyses are used to quantify the relationship between certain brain waves and mental fatigue. This research is a major step towards the development of a model that explores the relationship between mental fatigue and factors associated with output performance, optimal recuperation periods and related variables. Such a model would be useful in human reliability prediction based on task parameters and worker profiles.     

新型军械装备损坏程度评估方法研究

根据新型军械装备损坏程度具有不确定性的特点,提出了基于D-S证据理论的新型军械装备损坏程度评估方法,并求出了新型军械装备损坏程度区分.通过对典型新型军械装备损坏程度的评估,验证了该方法的有效性和实用性.     

嵌入式疲劳驾驶监测系统的设计与实现

疲劳驾驶是引发恶性交通事故的重要原因之一,驾驶员疲劳监测技术近年来已逐步成为图像处理领域的一个研究热点。基于改进的和提出的新算法,设计了一个嵌入式驾驶员疲劳监测系统。由可见光/近红外摄像头采集视频,首先采用Haar特征的级联分类器从图像中检测出人脸区域,并用钻石搜索法跟踪人脸区域;然后提取一个新的图像差分统计特征,并结合3个准则判断疲劳状态;最后采用全变分模型消除图像中的非均匀光照,以便实现鲁棒的人眼定位和人脸识别。实验测试结果表明,本系统的疲劳状态监测准确率达到95%以上。     

基于ARM-Linux的钢丝绳损伤检测系统设计

针对现有钢丝绳检测系统实时性与适应性差、自动化程度低的问题,提出了一种基于ARM-Linux的高性能钢丝绳损伤检测系统的设计方案,详细介绍了该系统的硬件组成、工作原理、软件实现方法及实时采样曲线绘制的设计与实现。该系统结合嵌入式Linux技术和漏磁无损检测技术,可独立完成检测任务,实时显示检测波形,提高了检测效率。     

影视作品中“审丑”现象流行的原因——从王宝强的走红谈起

从王宝强走红影视圈的案例出发,讨论了当今影视作品中的"审丑"现象流行的原因。这种"丑",不涉及品德,而是单纯的外貌丑,而这种外貌丑又是相对的。认为"审丑"现象的产生主要基于观众的审美疲劳,时代导致审美趋向多元化,把审美的意义赋予丑的形象,丑星的现实生活基础等几个原因。另外指出这种类型的丑星需要对自己加以调整、提高演技才能在影视圈走得更久,否则会引起观众的"审丑疲劳",不过是昙花一现。     

Work fatigue and physiological symptoms in different occupations of high-elevation construction workers

The objective of this study is to investigate whether work fatigue and physiological symptoms that high-elevation construction workers experience would be affected by the occupations. Questionnaires of demographic data and subjective fatigue symptoms as well as some physiological measurements were carried out, pre- and post-shift, on scaffolders, steel fixers, formworkers, electrician-plumbers, concreters and miscellaneous workers at a high-rise building construction site. This study found that some subjective fatigue symptoms coincide with the life style of some workers and that the extent of fatigue symptoms and physiological strains varies among different occupations of construction workers. Scaffolders, steel fixers and formworkers are categorized as physically demanding fatigue type of workers, while concreters, electrician-plumbers and miscellaneous workers as general type. The prevalence and occurrence of subjective fatigue symptoms indicate high-elevation workers have more complaints of “projection of physical impairment” than “drowsiness and dullness” and “difficulty in concentration”. Some unexpected changes (i.e., post-shift measurements are greater than pre-shift ones) in some strength tests in scaffolders and concreters were consistent with the observations of how they exercised their bodies during work shift. Considerable variation of average heart rate among occupations was found, with scaffolders the highest and concreters the lowest. This study concludes that questionnaires of subjective fatigue symptoms and some physiological measurements can be used as indicators to predict the extent of strains or hazards which construction workers encounter. In terms of management program of safety and health, more attention should be paid to those physically demanding workers, such as scaffolders, workers with lower sense of safety and health, such as miscellaneous workers, and workers with older age, such as concreters.     

A modified version of the three-compartment model to predict fatigue during submaximal tasks with complex force-time histories

The three-compartment model (3CM) was validated previously for prediction of endurance times by modifying its fatigue and recovery rates. However, endurance times do not typically represent work demands, and it is unknown if the current version of the 3CM is applicable for ergonomics analysis of all occupational tasks. The purpose of this study was to add biological fidelity to the 3CM, and validate the model against a series of submaximal force plateaus. The fatigue and recovery rates were modified to represent graded physiological motor unit characteristics (termed 3CM_GMU). In nine experiments of submaximal efforts, the 3CM_GMU produced a root-mean squared difference (RMSD) of 4.1 ± 0.5% MVC over experiments with an average strength loss (i.e. fatigue) of 31.0 ± 1.1% MVC. The 3CM_GMU model performed poorly for endurance tasks. The 3CM_GMU model is an improvement for evaluating submaximal force patterns consisting of intermittent muscle contractions of the hand and forearm.

Practitioner Summary: We modified an existing fatigue model using known physiological properties in order to predict fatigue during nine different submaximal force profiles; consistent with efforts seen in industrial work. We expect this model to be included in digital human modelling software, for the assessment of repetitive work and muscle fatigue in repetitive tasks.

Social Media Summary: The proposed model has applications for estimating task fatigue in proactive ergonomic analyses of complex force patterns using digital human models.     

On the relationship between subjective and objective measures of fatigue

Objective: Objective and subjective methods have been used in the past to assess workplace fatigue, but little is known about correlations between them. We examine correlations between subjective and objective measures, including measures collected in a workplace scenario. Methods: 15 young and 17 older participants were assessed before and after work with four types of fatigue measure: objective physical (posturography), objective mental (psychomotor vigilance task), subjective physical and mental (self-assessment), objective and subjective realistic (oculomotor behaviour, observer-rated facial expression, typing performance). Results: Pre- and post-test scores were analysed with an ANOVA, significant differences were submitted to a factor analysis. It yielded three factors: one representing posturography, the second self-rated mental and physical fatigue and the third observer-rated facial expression. Conclusions: Results advocate the existence of three independent fatigue components: Objective physical fatigue, introspective and extrospective fatigue.

Practitioner Summary: This study analyses correlations between different subjective and objective fatigue markers to better understand the complex nature of workplace fatigue. Measurements were conducted directly at the workplace. Results reveal that fatigue comprises three independent fatigue components: Objective physical fatigue, introspective and extrospective fatigue.     

Do you get tired of socializing? An empirical explanation of discontinuous usage behaviour in social network services

Based upon the stressor-strain-outcome framework, this study proposes that perceived system feature overload, information overload, and social overload are stressors which induce strain, in terms of social network fatigue and dissatisfaction. Both of social network fatigue and dissatisfaction further influence discontinuous use intention. The empirical results indicate that three types of perceived overload exert greater effects on social network fatigue than dissatisfaction, both of which further increase users’ intention of discontinuance. The study also finds that demographic characteristics, such as gender and age, also have moderating effects on these relationships.     

军事铁路运输风灾防护系统模块设计

风灾防护系统对于保障军交运输安全具有重要意义。本文针对风灾防护系统应用的不足,开展了需求分析,进行了工作模块设计,并提出了预警模式判别方法和防护措施的设计。该系统的逻辑步骤和模块设计符合强风条件下行车安全多因素决定性的客观特征,其具有成本优势。