中小学教师工作相关肌肉骨骼疾患及其危险因素的研究

目的为了解中小学教师工作相关肌肉骨骼疾患现状,探讨其发生的危险因素,制定针对性预防措施提供科学依据。方法对某市7所中小学教师进行工作相关肌肉骨骼疾患的横断面调查。结果在时间段为过去1 a内,肌肉骨骼疾患患病率颈部最高(42.0%),依次为肩(35.9%),腰(38.4%),背(29.2%);肌肉骨骼损伤的患病率高中教师明显高于初中和小学教师,其中身体的9个部位患病率的差异均有统计学意义;颈、肩部位患病率女性高于男性。工作相关肌肉骨骼疾患的危险因素:长时间坐位、站立、同一姿势,长时间保持扭转姿势,没有东西可以倚靠,没有充足的休息时间,每周课时≥14 h。结论教师的职业因素与肌肉骨骼损伤发生具有很强的相关性。     

A method to design job rotation schedules to prevent work-related musculoskeletal disorders in repetitive work

Job rotation is an organisational strategy widely used in human-based production lines with the aim of preventing work-related musculoskeletal disorders (WMSDs). These work environments are characterised by the presence of a high repetition of movements, which is a major risk factor associated with WMSDs. This article presents a genetic algorithm to obtain rotation schedules aimed at preventing WMSDs in such environments. To do this, it combines the effectiveness of genetic algorithms optimisation with the ability to evaluate the presence of risk by repeated movements by following the OCRA ergonomic assessment method. The proposed algorithm can design solutions in which workers will switch jobs with high repeatability of movements with other less demanding jobs that support their recovery. In addition, these solutions are able to diversify the tasks performed by workers during the day, consider their disabilities and comply with restrictions arising from the work organisation.     

基于OWAS方法的选煤厂工人肌肉骨骼损伤分析

探讨选煤厂拣矸作业中危险姿势对工人肌肉骨骼损伤的影响。通过问卷调查和工作姿势分析系统（OWAS）对工人不良作业姿势重复出现的比例以及身体损伤状况进行评估与分析。结果显示工人背部和颈部出现不良作业姿势的比例、危害和损伤程度较高。这与疲劳自觉症状调查和OWAS系统分析所得出的结果基本一致。采取恰当的轮岗方式,增加座椅以及防护装备可有效降低工人肌肉骨骼的损伤程度,同时会更好的提高工作表现并减少工伤事故的发生。     

肌肉骨骼疾患风险评估方法趋势研究

目的肌肉骨骼疾患是与工作姿势有关的主要职业病,不仅影响工人的健康,而且对经济造成巨大的损失。而不良的工作姿势是引发肌肉骨骼疾患的主要原因。因此评估工作姿势所造成的肌肉骨骼疾患并采取科学的纠正措施逐渐成为相应领域研究的热点问题。基于现有对肌肉骨骼疾患风险评估方法的研究现状和未来趋势进行分析与展望。方法通过对肌肉骨骼疾患、人因风险评估、人体姿态识别等核心概念的相关文献进行梳理和归纳,论述了肌肉骨骼疾患风险评估的主要方法,并重点分析了图像识别技术在肌肉骨骼疾患风险评估中的应用,结合人体骨架与神经网络算法模型对作业姿势进行识别,探讨了人工智能环境下,基于图像识别的评估方法中待解决的难点问题,对未来可能发展趋势进行预测。结论将肌肉骨骼风险评估方法总结为三大类,并分析其在现场评估应用过程中的优缺点;结合图像识别技术的发展,对肌肉骨骼风险评估提出了展望,即智能化自动化评估、多评估方法融合、多通道特征识别。     

Human posture simulation to assess cumulative spinal load due to manual lifting. Part II: accuracy and precision

For assessing a large number of variable manual lifting jobs, posture specification for using the University of Michigan Three Dimensional Static Strength Prediction Program and the revised National Institute for Occupational Safety and Health Lifting Equation may be time-consuming, tedious and subject to human errors. To expedite data analysis with desirable accuracy and precision for the two risk assessment tools, a new data analysis method based on human posture simulation was developed and evaluated. The accuracy and precision of the posture simulation method were evaluated by a repeated measures study design with six postures, three viewing angles and three trial repetitions as experimental factors. The effects of the experimental factors on the average accuracy and precision of the simulation method are reported and discussed. The study results also demonstrated pros and cons of human posture simulation as a means of posture specification for ergonomic risk assessments. The findings about the accuracy and precision of the human posture simulation method for quantifying the risk of musculoskeletal disorders due to manual materials handling may provide researchers with a new way of ergonomic assessments.     

Truck adaptive following distance based on threat assessment under variable conditions

Vehicle-stopping distance and recommended following distance are important factors for heavy-duty truck safety. The practical vehicle stopping-distance is affected by several factors beside vehicle dynamics: current speed, braking system retardation force, road slip and road grade. One of the purposes of truck onboard monitoring is to provide real-time feedback to the driver that could have two forms: a warning to the driver for any threat of frontal collision; or advisory information. Both are based on threat assessment and thus are equivalent in theory. Most previous work in the literature only provides threat assessment and warning under ideal cases that is, flat, straight, dry and concrete road surface conditions. The authors systematically investigate vehicle stopping distance under variable conditions, based on which the corresponding recommended following distance is generated. Although it is difficult for the driver to estimate the following distance visually, sensor detection plus appropriate feedback to the driver can achieve the same goal. Practical implementation issues and field test results are also presented. They show how significantly the environmental factors affect the threat assessment and the recommended following distance. The results are readily applicable to the development of safety systems for other types of vehicles.     

特定作业环境下作业姿势的研究

针对某厂实际生产过程中的铆接工序,研究了作业环境对作业姿势的限制,提出了考虑人因的作业规划,设计了3种人体作业姿势方案.利用人因工程学原则,分别对每种姿势进行了可行性分析;利用人因软件对各方案进行了视觉分析、手的操作范围分析和人体负荷计算.在对各方案综合分析评价的基础上,结合实际生产过程中的设备情况,确定了该力工环境下最优的作业姿势.     

"Videolized" atomic force microscopy for interactive nanomanipulation and nanoassembly

The main problem in nanomanipulation and nanoassembly using atomic force microscopy (AFM) is its lack of real-time visual feedback during manipulation. Fortunately, this problem has been solved by our recently developed augmented reality system, which includes real-time force feedback and real-time "videolized" visual feedback. Through the augmented reality interface, the operator can monitor real-time changes of the nanoenvironment during nanomanipulation through a movie-like AFM image. In this paper, the behavior of some nanowires under pushing is theoretically analyzed and the interaction among the tip, substrate, and nanowires has been modeled. Based on these models, the real-time interactive forces can be used to locally update the AFM image in order to obtain movie-like visual feedback in video frame rate. This augmented reality enhanced system capable of manipulation of nanoparticles and nanowires helps the operator to perform several operations without the need of a new image scan. AFM-based nanoassembly becomes feasible through this newly developed system.     

坐姿工作者躯干慢性肌肉骨骼损伤工效学分析

躯干慢性肌肉骨骼损伤(CMI)是坐姿体位工作人群的一类与工作有关疾病．为了研究坐姿体位与颈椎病、肩颈痛和下背痛的联系，文章调查分析了709名坐姿体位、836名坐立交替体位和648名站立体位工作人员躯干CMI患病情况，调查结果表明，坐姿体位人群肩颈和下背部CMI患病率比其他2种体位人群明显升高，不同坐姿体位间患病率也存在差异。结果提示长期坐姿工作是躯干CMI患病危险因素之一，不同坐姿体位对CMI发病也会产生较大影响。     

Use of multi-objective optimization for digital human posture prediction

With sufficient fidelity, the use of virtual humans can save time, money, and lives through improved product design, process design, and understanding of behaviour. Optimization-based posture prediction is a unique tool, and this article presents a study that advances posture prediction with a multi-objective optimization (MOO) approach. MOO is used to both develop and combine the following human performance measures: joint displacement; musculoskeletal discomfort; and a variation on potential energy. The following MOO methods are studied in the context of human modelling: objective sum; min–max; and global criterion. Using MOO yields realistic results. Of the independent performance measures, discomfort generally provides the most accurate postures. Potential energy, however, is not a significant factor in governing human posture and should be combined with other performance measures. The three MOO methods for combining performance measures yield similar results, but the objective sum provides slightly more realistic postures.     

The Effect of Jar Holding Posture on Finger Force and Torque during a Jar‐Opening Task for Young Females

Many young females have difficulty opening jars. Although previous studies have attempted to clarify the body posture effect during such a task, the experiments therein focused on a single digit or actions with unnatural finger positions and were further restricted to upper extremity postures. A further study is required to investigate the fingers’ coordination, as well as each subject's natural and self‐selected upper extremity posture and finger grasp location when opening a jar. This study focused on the forces and coordination of the right hand fingers during a jar opening movement under both vertical and free‐way opening postures. A jar simulator was set up to record the forces applied by finger groups (the thumb, the index–middle finger group, and the ring–little finger group) of the right hand. A self‐selected finger position and free‐arm posture of each subject were allowed. Results show that the force vectors of the finger groups were all in the counterclockwise direction for both postures. The total force and overall torque of the right hand decreased in the vertical opening posture. The thumb produced greater tangential and resultant forces in the vertical opening posture. Despite normal forces being 1.82–3.54 times the tangential forces for both postures, no difference was found for the normal force to tangential force ratio for each finger group between the two opening postures. The index–middle finger group had similar torque contributions for both postures. The torque contribution of the thumb increased (26% and 21% for vertical and free‐way posture, respectively), while the ring–little finger group torque contribution decreased (35% and 42% for vertical and free‐way posture, respectively) in the vertical opening posture. As such, the free‐way opening posture is the better strategy for young females to open a jar. Copyright © 2013 John Wiley & Sons, Ltd.     

基于LabVIEW平台的ABX测试系统

讨论了一种基于LabVIEW平台，用于测试人耳对音频信号失真程度主观评价的ABX测试系统。该系统人机界面友好，提供了一个用于测试音频信号失真是否能被人耳识别的音质测试平台。该系统可用于对音频水印算法以及音频信号和语音编码等系统的性能评价。     

Human performance reliability: on-line assessment using fuzzy logic

This paper presents an on-line approach to monitoring human performance in terms of conditional reliability when one is performing a task. Unlike traditional human reliability analysis, this approach develops a dynamic model that is able to cope with constantly changing conditions that affect operator performance. A fuzzy knowledge-based assessment approach is developed in order to deal with uncertainty and subjectivity associated with human performance assessment. This technology includes three main parts/functions: (i) on-line performance monitoring; (ii) real-time performance forecasting; and (iii) performance reliability assessment. The technology is demonstrated in real-time and provides timely conditioned reliability information regarding task success/failure. In general, this technology offers human reliability assessment under highly dynamic circumstances.     

exLOPA for explosion risks assessment

The European Union regulations require safety and health protection of workers who are potentially at risk from explosive atmosphere areas. According to the requirements, the operators of installations where potentially explosive atmosphere can occur are obliged to produce an explosion protection document. The key objective of this document is the assessment of explosion risks. This paper is concerned with the so-called explosion layer of protection analysis (exLOPA), which allows for semi-quantitative explosion risk assessment for process plants where explosive atmospheres occur. The exLOPA is based on the original work of CCPS for LOPA but takes into account some typical factors appropriate for explosion, like the probability that an explosive atmosphere will occur, probability that sources of ignition will be present and become effective as well as the probability of failure on demand for appropriate explosion prevention and mitigation means.     

Human posture simulation to assess cumulative spinal load due to manual lifting. Part I: methods

The estimation of cumulative spinal load (CSL) resulting from exposure to manual materials handling (MMH) may provide a sensitive method for assessing the risk of highly varying exposures. This article reports on a CSL method that involves human posture simulation of workers from videotape in order to assess spinal load exposures due to MMH. The proposed method appears to be sensitive to different durations of exposure, easy to use and useful for assessing jobs with a high degree of variability in task characteristics between lifts. Although the method remains to be validated, it appears to be a useful addition to the range of tools available for assessing manual lifting exposures in worksite-based epidemiologic studies. Ergonomic methods are lacking for assessing highly variable MMH tasks, such as tasks found in warehousing. The existing methods do not include sufficient factors to account for variable exposure patterns or tasks with highly variable task characteristics, such as varying load weights and lift geometries. The CSL assessment method described in this article may provide a way to evaluate these types of tasks in order to assess the overall risk of workers developing work-related musculoskeletal disorders.     

木工上半身肌肉负荷影响的差异性定量研究

目的在特定实验任务中,对专业木工和初学者木工的表面肌电图信号进行差异性分析,为木工提供合理的工作策略指导其减少工作相关肌肉骨骼疾患(WMSDs)的发病率。方法本研究模拟木工的工作任务,测定21名专业木工和21名初学者木工的4块前臂肌肉(肱桡肌、尺侧腕伸肌、尺侧腕屈肌、桡侧腕屈肌),3块肩部肌肉(前部三角肌、中部三角肌、后部三角肌)和斜方肌的表面肌电信号(sEMG)差异,并以经验水平、工作任务和肌肉类别为对比项对表面肌电信号的平均值和峰值统计学分析。结果专业木工和初学者木工之间sEMG的均值和峰值无显著性差异,初学者木工8块肌肉都表现出较高的肌肉活动水平;从局部肌肉的sEMG均值和峰值来看,木工工作任务对前部三角肌和后部三角肌造成较大肌肉负荷;经验水平、工作任务和肌肉类别对专业木工和初学者木工上半身的肌肉负荷的影响有显著差异。结论经验对木工的肩膀肌肉负荷有较大缓解作用,对降低木工工作时的肌肉疲劳度和损伤风险度具有积极作用。     

“行为-力”同步可视化展示系统的开发

动物行为信号的同步可视化展示为分析和理解动物的运动行为特征提供了有效手段。为了便于直观分析人的运动姿态与脚底接触力的关系,搭建了“行为-力”同步可视化展示系统。首先,利用LabVIEW软件实现了基于UDP （user datagram protocol,用户数据报协议） 的多通道三维力传感器和Kinect相机的信号采集;其次,提出了一种基于插值的数据同步处理方法,实现了运动姿态信号与脚底受力信号的同步处理;然后,采用多线程技术构建了同步实时可视化的虚拟展示系统,实现了运动轨迹、运动姿态和脚底接触力的同步实时展示;最后,通过实验验证了该展示系统具有较好的实时性。研究结果表明,“行为-力”同步可视化展示系统是研究动物运动行为特征的有效装置。     

A combined fuzzy DEMATEL and cloud model approach for risk assessment in process industries to improve system reliability

Decision-making trial and evaluation laboratory (DEMATEL) analysis is an effective and comprehensive method for identifying accident factors and converting the relationships among them into a visual structural model. Traditionally, the mean value method is adopted to summarize the initial direct-relation matrix, but it ignores the errors caused by differences in expert knowledge. In addition, a single qualitative risk assessment may not be sufficiently comprehensive and persuasive. The qualitative risk assessment results may not play a complete role in helping industrial plants carry out safety management. Therefore, this study proposes a quantitative risk assessment model based on the cloud model (CM) called the fuzzy DEMATEL-CM. An assessment index model is established by identifying the hazards associated with a converter steelmaking system. Subsequently, fuzzy DEMATEL analysis is applied to determine the relationships among the assessment indices and calculate their weights. Then, the CM is utilized to calculate the risk levels of the assessment indices and determine the comprehensive risk level. Finally, a case study is introduced to verify the practicability and validity of this model, and it is observed that the model has a certain superiority in solving uncertain problems. The quantitative risk assessment results are helpful for preventing accidents to improve the reliability of converter steelmaking plants.     

Critical factors and paths influencing construction workers’ safety risk tolerances

While workers’ safety risk tolerances have been regarded as a main reason for their unsafe behaviors, little is known about why different people have different risk tolerances even when confronting the same situation. The aim of this research is to identify the critical factors and paths that influence workers’ safety risk tolerance and to explore how they contribute to accident causal model from a system thinking perceptive. A number of methods were carried out to analyze the data collected through interviews and questionnaire surveys. In the first and second steps of the research, factor identification, factor ranking and factor analysis were carried out, and the results show that workers’ safety risk tolerance can be influenced by four groups of factors, namely: (1) personal subjective perception; (2) work knowledge and experiences; (3) work characteristics; and (4) safety management. In the third step of the research, hypothetical influencing path model was developed and tested by using structural equation modeling (SEM). It is found that the effects of external factors (safety management and work characteristics) on risk tolerance are larger than that of internal factors (personal subjective perception and work knowledge & experiences). Specifically, safety management contributes the most to workers’ safety risk tolerance through its direct effect and indirect effect; while personal subjective perception comes the second and can act as an intermedia for work characteristics. This research provides an in-depth insight of workers’ unsafe behaviors by depicting the contributing factors as shown in the accident causal model developed in this research.     

Lifecycle risk assessment of a technological system using dynamic Bayesian networks

Investigations of technological systems accidents reveal that technical, human, organizational, as well as environmental factors influence the occurrence of accidents. Despite these facts, most traditional risk assessment techniques focus on technical aspects of systems and have some limitations of incorporating efficient links between risk models and human and organizational factors. This paper presents a method for risk analysis of technological systems. Application of the presented framework makes it possible to analyze the influence of technical, human, organizational, and environmental risk factors on system safety. It encompasses system lifecycle from design to operational phase to give a comprehensive picture of system risks. The developed framework comprises the following main steps: (1) development of a conceptual risk analysis framework, (2) identifying risk influencing factors in different levels of technical, human, organizational, and environmental factors providing the possibility of analyzing interactions in a multi‐level system, (3) modeling system risk using dynamic Bayesian network (DBN), (4) assignment of probabilities and risk quantification in node probability tables (NPTs) based on industry records and experts extracted knowledge, (5) implementation of the model for wind turbines risk analysis combining use of V‐model, risk factors, and DBN in order to analyze the risk, and (6) analyzing different scenarios and the interactions in different levels. Finally, the various steps of the framework, the research objective fulfillment, and case study results are presented and discussed.