Bernardino Ramazzini's early observations of the link between musculoskeletal disorders and ergonomic factors

Bernardino Ramazzini (1633-1714) systematically studied the relationship between work and diseases. He realized that it was not possible to ascribe all workers' diseases to chemicals or physical agents and foresaw that other factors were involved. He observed that common diseases could originate following the maintenance either of prolonged stationary postures or of unnatural postures (e.g. bakers, workers who stand, sedentary worker, scribes, weavers) or following activities requiring heavy muscular performance (e.g. porters and woodworkers). Furthermore, Ramazzini recognized the need to undertake measures to prevent disorders from repetitive motions and manual lifting and anticipated the now accepted advice of moderation and recommendations of reduction of work duration for a number of hard jobs requiring a standing position or severe muscular effort. From his early writings therefore it is evident that Ramazzini realized the importance of assessing the ergonomic factors associated with the occurrence of work-related musculoskeletal disorders.     

Association between objective and subjective measurements of comfort and discomfort in hand tools

In the current study, the relationship between objective measurements and subjective experienced comfort and discomfort in using handsaws was examined. Twelve carpenters evaluated five different handsaws. Objective measures of contact pressure (average pressure, pressure area and pressure-time (P-t) integral) in static and dynamic conditions, muscle activity (electromyography) of five muscles of the upper extremity, and productivity were obtained during a sawing task. Subjective comfort and discomfort were assessed using the comfort questionnaire for hand tools and a scale for local perceived discomfort (LPD). We did not find any relationship between muscle activity and comfort or discomfort. The P-t integral during the static measurement (beta=-0.24, p<0.01) was the best predictor of comfort and the pressure area during static measurement was the best predictor of LPD (beta=0.45, p<0.01). Additionally, productivity was highly correlated to comfort (beta=0.31, p<0.01) and discomfort (beta=-0.49, p<0.01).     

Objective and subjective assessments of lighting in a hospital setting: implications for health,safety and performance

A field study was conducted to evaluate the illumination levels, to examine the effect of lighting conditions (including lighting characteristics and disturbances) on employee satisfaction, job performance, safety and health, and to compare the employees' perception of lighting level with actual illuminance levels in a hospital setting using both questionnaire and physical illuminance measurements. The illumination levels varied across different locations within the hospital and were lower than standards for 52.2% of the workplaces surveyed. Most respondents indicated that at least one of the four lighting characteristics (i.e. light level, type of light sources, light colour and use of daylight) was inappropriate, and that at least one of the three lighting disturbances (i.e. flickering lights, glare and unwanted shadows) was a major disturbance to them. The employees' perceptions of illuminance generally reflected the actual illuminance levels. The more appropriate maintenance or installation of lighting fixtures was rated as the most appropriate for improving lighting. The findings suggest that environmental ergonomics should be given a more prominent role in hospital building and workplace design to support safer healthcare facilities (for staff and potentially for patients).

Practitioner Summary: Good lighting is essential to improve employee performance, health and safety. The findings suggest that quantitative physical measurements should be supplemented by qualitative subjective assessments to provide a more holistic approach where specific details about the lighting condition in each working environment are incorporated from the workers' perspective.     

Assessing environmental impact of small and medium ceramic tile manufacturing enterprises in Thailand

Manufacturing processes employed by small and medium ceramic tile production enterprises in Thailand consume substantial amounts of energy. This study reveals that a small plant uses twice as much energy to produce one square meter of tile than does a medium plant. With the exception of global warming effects, the environmental impacts of a small plant are also larger than those of a medium plant, specifically with respect to ozone depletion, acidification and eutrophication. In addition, the environmental management perspective of the medium plant is based on cost reduction and social necessity. In contrast, the small plant has a negative attitude toward environmental management measures, taking the view that these are not appropriate concerns for small plants. These differing impacts and viewpoints suggest that environmental management in the small and medium plants should apply different approaches. On the one hand, the medium plant should emphasize the accelerated transfer of environmental knowledge to its personnel, while on the other, the owners of the small plant should be made to recognize the environmental impacts of their production activity and products. Additionally, potential benefits that might accrue to the plant owner from environmental impact mitigation should be highlighted.     

Impact of multimodal feedback on simulated ergonomic measurements in a virtual environment: A case study with manufacturing workers

The purpose of this study was to evaluate the impact of multimodal feedback on ergonomic measurements in a virtual environment (VE) for a typical simulated drilling task. In total, sixty male manufacturing industry workers were divided into five groups. One group performed the working task in a real environment (RE), and ergonomic measurements for this group were used as the baseline for evaluation. The other four groups performed the same task in a virtual environment with different feedback treatments (visual with or without auditory and/or tactile feedback). Five indices – task completion time, maximum force capacity reduction, body part discomfort, rated perceived exertion, and rated task difficulty – were used to evaluate the measurements of each of the four treatments in VE in comparison to the baseline group in RE. The results indicate that the five indices for each of the four treatment groups were significantly higher than those of the RE group. Moreover, the indices of the visual‐only group were significantly higher than those of the other three groups with auditory and/or tactile feedback treatments. The findings of this study can provide a guideline for ergonomic evaluations of work designs in VE and for establishing a virtual reality simulation system. © 2011 Wiley Periodicals, Inc.     

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.     

Causes of dissociation between subjective workload measures and performance ; Caveats for the use of subjective assessments

Dissociations between subjective workload assessments and performance were investigated. The difficulty of a Sternberg memory search task was manipulated by varying stimulus presentation rate, stimulus discernibility, value of good performance, and automaticity of performance. All Sternberg task conditions were performed both alone and concurrently with a tracking task. Bipolar subjective workload assessments were collected. Dissociations between workload and performance were found related to automaticity, presentation rate and motivation. The results were interpreted as supporting the hypothesis that the specific cognitive processes responsible for subjective assessments can differ from those responsible for performance. The potential contamination these dissociations could inflict on operational assessments was discussed.     

文本挖掘中主客观因素影响性的眼追踪研究

基于文本主题模型与眼动仪技术,从主题挖掘的客观角度与阅读兴趣的主观角度研究文本内容提取技术。传统文本挖掘多基于文本本身内容等客观因素,而主观取向的重要因素很少在文本挖掘中发挥作用。文章利用眼部追踪技术,先将眼动数据转换为阅读兴趣等主观结果形式,并利用LDA(Latent Dirichlet Allocation)模型对文本进行客观主题提取,继而对眼部数据与主题建模结果进行比较,提取分析主客观因素对文本挖掘的影响。新闻数据集的眼部追踪实验与主题提取实验显示了主客观因素对结果影响的具体差异性与相似性,未来两者结合并调控比率可作为对文本挖掘效果提升的基本方向。     

A checklist for model credibility,salience, and legitimacy to improve information transfer in environmental policy assessments

Modelers involved in environmental policy assessments are commonly confronted with the lack of uptake of model output by policy actors. Actors have different expectations of models, condensed into three quality criteria: credibility, salience, and legitimacy. The fulfilment of quality criteria is also dynamic as expectations vary, change, and possibly counteract each other. We present a checklist for modelers involved in model-based assessments that is aimed at the identification and monitoring of issues, limitations and trade-offs regarding model quality criteria. It draws upon the literature of integrated assessments as well as case study analysis of environmental policy assessments for the Dutch government, based on expert interviews and embedded experience. The checklist is intended to be consulted during assessments; its application may result in greater awareness among modelers involved in assessments regarding model quality criteria, and may positively affect the uptake of model-based knowledge from environmental policy assessments by policy actors.     

Ergonomics study and analysis of workstations in Tunisian mechanical manufacturing

The workers’ performance in the mechanical manufacturing sector is the main factor for the improvement of productivity and quality. At present, it seems that the available information on the ergonomics and the working environment of the mechanical manufacturing actors is scarce. This study deals with the relationship between the working method and the workstation in injection mold manufacturing. An original methodology, based on the survey of operators using participatory ergonomic tools, is proposed in order to evaluate the ergonomic performance of 3 workstations: milling, turning, and drilling. The surveys concerned 3 operators. Obtained results showed that ergonomics play a key role in improving mechanical manufacturing. The results obtained from the analysis showed that ergonomics has a key role in the quality of the various tasks performed by operators. Using the Rapid Entire Body Assessment (RULA) and Rapid Entire Body Assessment (REBA) investigation tools, the examination of the workstations revealed 4 machining operations and 12 operator postures that have a direct influence on the performance of all machining stations. In addition, data from the analysis conducted on injection mold manufacturing revealed that neither the workstations were ergonomic nor the operators complied with the ergonomic rules. Based on the results obtained, a new standardized score is proposed for the RULA and REBA calculations. This score was applied and validated through another study conducted in a leaf spring manufacturing plant. The results of these studies were concretized by proposing the digital factory where CATIA software was used for the virtual design of the ergonomic workstations and their environments.     

A computational model of the interaction between environmental dynamics and economic behavior

Environmental issues have been considered to be very important for a long time. We believe that they should be examined from an interdisciplinary view point in order to reach a solution, because they have arises as the consequence of complex interactions among various factors. This article proposes a new model termedColorChanger. By using this model, we aim to explore the nature of ecological issues beyond separate discussions on specific subjects, and make the acquired knowledge available to encourage the solution of environmental issues. This article also reports on the results of the preliminary experiments. This work was presented in part at the Sixth International Symposium on Artificial Life and Robotics, Tokyo, January 15–17, 2001     

Empirical relationship between near-IR reflectance of melting seasonal snow and environmental temperature in a Himalayan basin

The snow-melting zone forms a site of marked physical-hydrological processes. A basic requirement for monitoring such zones is the data on temperature distribution, for which the method of environmental lapse rate and remote sensing with thermal infrared scanners have been used earlier. In this study, repetitive multispectral image data sets acquired from IRS-LISS-III satellite sensor have been used for snow mapping in the Gangotri glacier, Himalayas, and topographically corrected reflectance values have been computed using a digital elevation model. Temperature measurements at a field station have been used for estimating temperature distribution in the snow-covered basin on the corresponding dates. It is shown here that in the melting seasonal snow zone, the topographically corrected mean near-IR reflectance systematically decreases from higher to lower elevation levels, and can be broadly related to the environmental temperature distribution in a restricted range of about 0-5 °C. As a large number of satellites routinely provide data in the reflected infrared range, this method appears to have a reasonable potential, at least to provide surrogate data for filling-in gaps in the database, with possible applications in environmental surveillance, runoff modeling, climatic modeling and numerous other snowfield studies.     

Research on risk assessment model of subjective and objective integration in manual handling work

The main hazards in the process of manual handling work are triggered by human factors and ergonomics. This study is intended to implement a valid approach to quantitatively evaluate the risk level during manual handling work. A risk assessment model for manual handling workers was proposed based on subjective and objective correlation. A simulation experiment of manual handling process was developed and an ergonomics evaluation method was carried out. The 33-point human joint model of BlazePose neural network and the Rapid Upper Limb Analysis (RULA) method were utilized to determine the risk posture and risk index of the manual handling workers. This study brought together hemodynamic parameters and the score of Borg Rating of Perceived Exertion (RPE) scale and Physical Resources Scale (PRS) to obtain the final comprehensive index of work risk. The results showed that the risk indexes from the three stages of the experiment obtained by RULA method were 3, 4, and 7. And the scores of comprehensive indexes obtained by the risk assessment model were 1.841, 1.900, and 1.987, suggesting that the evaluation model based on subjective and objective correlation had the same ability to determine the risk levels of different handling tasks. Therefore, the risk assessment model proposed in this study verified the effectiveness of the comprehensive evaluation index integrating hemodynamic parameters and subjective evaluation scores.     

Human factors in computer simulations of urban environment. Differences between architects and non-architects’ assessments

Computer visualisations are widely used to evaluate future urban environments in international competitions. Rapid technological progress in graphics computer software has enabled architects and landscape planners to produce sophisticated images that are not only capable of transmitting the characteristics of the future environment, they also manage to evoke in observers the sort of feelings and emotions which can only be aroused by experiencing the space. This present paper attempts to identify the affective responses that influence the evaluation of urban environment proposal, analysing the model of architects and non-architects’s preferences. A sample of 104 architects and 113 non-architects expressed their opinions on 48 urban computer simulations. The results show that for both groups the success of a digital visualisation is associated to the feelings of innovation and wellbeing. However, their assessments differ significantly because each group associates these feelings with different aspects. In general, architects are more critical in their assessments.     

The effect of physical training on objective and subjective measures of productivity and efficiency in industry

The aims of this study were to investigate the associations between an activity logbook and the RT3 accelerometer and to assess whether the RT3 can discriminate activity levels in healthy adults. Ten participants completed two trials wearing an RT3 accelerometer over a 4–6 h period and completed a detailed activity log. Results showed a poor correlation between the RT3 in moderate activities (r = 0.22) in comparison to low (r = 0.52) and hard (r = 0.70) from the logbook. A significant difference was found in average RT3 vector magnitude (VM) counts/min in each activity level (p < 0.0001). Discriminant analysis demonstrated that an RT3VM counts/min value of approximately 500 was found to have high sensitivity (88%), and specificity (88%) for discriminating between low and moderate activity levels from the logbook. This study found that accelerometry has the potential to discriminate activity levels in free living. This study is the first to investigate whether tri-axial accelerometry can discriminate different levels of free-living activity recorded in an activity logbook. The RT3 accelerometer can discriminate between low and moderate physical activities and offers a methodology that may be applicable to future research in occupational settings.     

CCPE: Methodology for a Combined Evaluation of Cognitive and Physical Ergonomics in the Interaction between Human and Machine

Evaluation methods of today often focus on cognitive ergonomics (such as mental workload or usability) or physical ergonomics (such as physical workload or body posture). This article describes an analytical methodology of a joint systematic search for potential deficiencies in the human–machine interaction; such as high physical and mental workload, use errors, usability problems, and physical ergonomic errors. The purpose with the joint search is to achieve a more holistic evaluation approach and make the evaluation cost more effective than when using separate evaluation methods for cognitive and physical ergonomic aspects. The methodology is task‐based, which makes it possible to use both with focus on the device design, as in development projects; as well as with focus on the procedure, in the operative organization. © 2012 Wiley Periodicals, Inc.     

Investigation of musculoskeletal symptoms and ergonomic risk factors among female sewing machine operators in Turkey

This cross-sectional study aimed to identify the prevalence of musculoskeletal symptoms and ergonomic risks in female sewing machine operators at a textile company. The study sample comprised all female sewing machine operators in the company. The sample included 283 sewing machine operators. Data were collected through the use of the adapted Nordic Musculoskeletal Questionnaire and by direct observations via the rapid upper limb assessment (RULA) to determine ergonomic risks. RULA is a validated tool for assessment of ergonomic risks. The mean age of the women was 30.2 (SD: 8.4) and the mean number of years of employment was 13.4 (SD: 5.5). The highest prevalence rates for the women’s musculoskeletal symptoms were in the trunk (62.5%), neck (50.5%), and shoulder (50.2%). Of the women, 65% had experienced musculoskeletal pain or discomfort over the last 6 months. Pain intensity of these symptoms was assessed with a visual analogue scale. The average pain intensity of the women was found to be 3.5 (SD: 2.8). Results of the RULA scores were found to be quite high. There were no employees who received RULA scores of 1–2, which indicates acceptable postures (all scores >5). The final RULA scores of 6.9 indicate that the participants’ postures at their work stations need to be investigated immediately.

Relevance to industry

This study based on the RULA method allowed to perform a rapid and quite correct evaluation tolls for SMOs. For this research population, the research findings provided fundamental data on the prevalence of musculoskeletal symptoms and ergonomic risks among Turkish female SMOs.     

Short and longer duration effects of protective gloves on hand performance capabilities and subjective assessments in a screw-driving task

The study investigated short and longer duration effects of gloves on hand performance capabilities (muscle activity, dexterity, touch sensitivity, finger pinch and forearm torque strength) and subjective assessments of discomfort and ease of manipulation when performing a light assembly task. The independent variables were hand condition with four levels (wearing cotton, nylon or nitrile gloves as well as barehanded) and point of time within the 2 h duration of the task (with measurements taken at 0, 30, 60, 90 and 120 min). Participants worked with a screwdriver to fit two components together using screws. Wearing gloves significantly increased the muscle activity, pinch strength and discomfort but reduced the dexterity and touch sensitivity. There was also a significant effect of task time on the muscle activity, dexterity, forearm torque strength and touch sensitivity, which indicates that the duration of the task should be an important consideration in glove evaluation studies and in the selection of work gloves.

Statement of Relevance:It is important to evaluate the effects of gloves on hand performance capabilities in a working context so that job demands can be taken into account and the most appropriate type of glove be chosen for each task. This study gives recommendations regarding the evaluation and use of gloves for screw-driving tasks.     

Environmental conservation in the domestic domain: the influence of technical design features and person-based factors

This article presents three experiments that examined proenvironmental behaviour during utilisation of electrical consumer products in the domestic domain. One experiment was carried out in the laboratory (N?=?48), two others in the field (N?=?18, N?=?24). First, the work aimed to evaluate various ergonomic measures with regard to their effectiveness to influence proenvironmental behaviour. Second, it examined the relation of person-based factors (e.g., environmental concern) and behaviour. Third, it examined the generalizability of findings from the laboratory to a field setting. The results suggested that design modifications of kettle (e.g., kettle size, integrated user support) are effective in improving proenvironmental behaviour (i.e., resource consumption). Relationships between person-based factors and behaviour have been found, though they were not consistent because the nature of the relationship may be modified by design features (e.g., integrated user support). There was general confirmation of the results from the lab-based experiment by field research, suggesting the suitability of laboratory work to research environmental issues in the domestic domain.