State of science: occupational slips,trips and falls on the same level*

Occupational slips, trips and falls on the same level (STFL) result in substantial injuries worldwide. This paper summarises the state of science regarding STFL, outlining relevant aspects of epidemiology, biomechanics, psychophysics, tribology, organisational influences and injury prevention. This review reaffirms that STFL remain a major cause of workplace injury and STFL prevention is a complex problem, requiring multi-disciplinary, multi-faceted approaches. Despite progress in recent decades in understanding the mechanisms involved in STFL, especially slipping, research leading to evidence-based prevention practices remains insufficient, given the problem scale. It is concluded that there is a pressing need to develop better fall prevention strategies using systems approaches conceptualising and addressing the factors involved in STFL, with considerations of the full range of factors and their interactions. There is also an urgent need for field trials of various fall prevention strategies to assess the effectiveness of different intervention components and their interactions.

Practitioner Summary: Work-related slipping, tripping and falls on the same level are a major source of occupational injury. The causes are broadly understood, although more attention is needed from a systems perspective. Research has shown preventative action to be effective, but further studies are required to understand which aspects are most beneficial.     

Occupational and environmental risk factors for falls among workers in the healthcare sector

Falls are a leading cause of occupational injury for workers in healthcare, yet the risk factors of falls in this sector are understudied. Falls resulting in workers' compensation for time-loss from work from 2004–2007 for healthcare workers in British Columbia (BC) were extracted from a standardised incident-reporting database. Productive hours were derived from payroll data for the denominator to produce injury rates; relative risks were derived through Poisson regression modelling. A total of 411 falls were accepted for time-loss compensation. Compared to registered nurses, facility support workers (risk ratio (95% CI) = 6.29 (4.56–8.69)) and community health workers (6.58 (3.76–11.50)) were at high risk for falls. Falls predominantly occurred outdoors, in patients' rooms and kitchens depending on occupation and sub-sector. Slippery surfaces due to icy conditions or liquid contaminants were a leading contributing factor. Falls were more frequent in the colder months (January–March). The risk of falls varies by nature of work, location and worker demographics. The findings of this research will be useful for developing evidence-based interventions.

Statement of Relevance: Falls are a major cause of occupational injury for healthcare workers. This study examined risk factors including occupation type, workplace design, work setting, work organisation and environmental conditions in a large healthcare worker population in BC, Canada. The findings of this research should contribute towards developing evidence-based interventions.     

A comparison of foot/ground interaction during stair negotiation and level walking in young and older women

Stair design and environmental conditions may play a role in slip accidents on stairs in the workplace, but little is known about the slip resistance requirements on stairs compared to level walking. Older adults have an increased risk of falling compared to younger adults and may be at greater risk during stair negotiation. The purpose of this study was to determine whether the ground reaction force profiles and peak required coefficient of friction (RCOF) differed between young and elderly women or between stair ascent, stair descent and overground walking. While there was a trend towards less risky stair descent behaviour in the older women in terms of their peak RCOF values during stair descent, the increased vertical loading rate in the older women may imply reduced dynamic balance control. The largest mean RCOF peaks occurred during stair ascent in both young and older women, but there were several overground walking trials in both groups and a few stair descent trials of the young women, which resulted in RCOF peaks greater than 0.5. These results should be considered when choosing stair surface materials, particularly in occupational and outdoor settings where the tread surfaces may become wet or contaminated.     

机种机型运动识别方法的研究

本文在文章的思路下(即根据不同机种机型具有不同的运动性能对飞机进行机种机型的识别),以美军战斗机和攻击机为例,对识别过程中存在的关键问题的解决进行了讨论。     

Physiological cost of energy-equivalent noise exposures with a rating level of 85 dB(A):: Hearing threshold shifts associated with energetically negligible continuous and impulse noise

In industry continuous or impulse noise does not occur exclusively; rather it is a combination of both. If low-level continuous noise or impulse noise (below 120 dB) is added to an already existing high-level continuous noise this often numerically causes no essential increase in the rating level. Yet, it cannot be expected that also aural strain of these exposures is always negligible. Therefore, in a cross-over test series, ten male subjects (Ss) were exposed to white noise of 94 dB(A) for 1 h (TS I), energy-equivalent to an 8 h-rating level L_Ard of 85 dB(A). In a second test series (TS II) the same exposure was combined with 900 energetically negligible 5-ms impulses with a noise level of 113 dB(A) which increased the rating level by only 0.4 dB. The noise exposure of TS I and TS II was followed by an idealized resting phase in a soundproof cabin. In a third test series (TS III) the continuous noise of 94 dB(A) / 1 h was followed by 3 h of white noise at 70 dB(A). Such an additional load increases the L_Ard by merely 0.1 dB to 85.1 dB(A). In all three test series, the noise-induced temporary threshold shift (TTS₂) and its restitution were measured. The continuous noise exposure of 94 dB(A) for 1 h was associated with a TTS₂ of around 20 dB which disappeared completely after about 2 h. The additional impulse noise caused a small increase in the TTS₂ and a prolongation of the restitution time. The maximum mean temporary threshold shift for the group increased only slightly (from 22.5 to 25.9 dB, which nevertheless can be statistically proven at a significance level of p 0.99). Yet, more importantly, the restitution time increased from 126 to 175 min, i. e. 3 h, which can be statistically proven at a significance level of p0.95. The TTS₂-values of TS III did not differ significantly from those resulting from TS I. That was expected as the conditions up to that point in time were identical. But due to the additional subsequent exposure, the mean restitution time increased considerably from 126 min up to 240 min (4 h). The mean total physiological cost represented by the integrated restitution temporary threshold shift (IRTTS) increased in TS II by approximately 40% and in TS III even by 140%.

Relevance to industry

The results of the study show that levels of noise which have no influence on the rating level which traditionally is calculated according to the energy-equivalence principle are often of great importance, as they can lead to considerably prolonged restitution times. Therefore, the purely energy-equivalent determination of the rating level of both impulse noise and low sound levels can lead to an underestimation of latent problems so that over time a reversible TTS can evolve into a permanent threshold shift. The results are also of importance for the acoustic design of break rooms for noise-exposed workers. There should be conditions that allow an undisturbed restitution of hearing.     

A fuzzy reasoning and fuzzy-analytical hierarchy process based approach to the process of railway risk information: A railway risk management system

Risk management is becoming increasingly important for railway companies in order to safeguard their passengers and employees while improving safety and reducing maintenance costs. However, in many circumstances, the application of probabilistic risk analysis tools may not give satisfactory results because the risk data are incomplete or there is a high level of uncertainty involved in the risk data. This article presents the development of a risk management system for railway risk analysis using fuzzy reasoning approach and fuzzy analytical hierarchy decision making process. In the system, fuzzy reasoning approach (FRA) is employed to estimate the risk level of each hazardous event in terms of failure frequency, consequence severity and consequence probability. This allows imprecision or approximate information in the risk analysis process. Fuzzy analytical hierarchy process (fuzzy-AHP) technique is then incorporated into the risk model to use its advantage in determining the relative importance of the risk contributions so that the risk assessment can be progressed from hazardous event level to hazard group level and finally to railway system level. This risk assessment system can evaluate both qualitative and quantitative risk data and information associated with a railway system effectively and efficiently, which will provide railway risk analysts, managers and engineers with a method and tool to improve their safety management of railway systems and set safety standards. A case study on risk assessment of shunting at Hammersmith depot is used to illustrate the application of the proposed risk assessment system.     

Aggregation of direct and indirect judgments in pairwise comparison matrices with a re-examination of the criticisms by Bana e Costa and Vansnick

In a recent paper by Bana e Costa and Vansnick [C.A. Bana e Costa, J.C. Vansnick, A critical analysis of the eigenvalue method used to derive priorities in AHP, European Journal of Operational Research 187 (3) (2008) 1422-1428], analytic hierarchy process (AHP), particularly its eigenvector method (EM) used for deriving priorities from pairwise comparison matrices, was criticized for the violation of a so-called condition of order preservation (COP). Due to this violation, the EM was considered to have a serious fundamental weakness which makes the use of AHP as a decision support tool very problematic. The consistency ratio (CR) index in the AHP was also criticized for its failure to act as an alert of this violation of COP. In this paper, we look into decision makers’ overall judgments which can be obtained through the aggregation of their direct and indirect judgments and then re-examine Bana e Costa and Vansnick’s numerical examples with a detailed analysis to show the invalidity of their criticisms.     

A method for predicting the risk of virtual crashes in a simulated driving task using behavioural and subjective drowsiness measures

Abstract

This study proposed a procedure for predicting the point in time with high risk of virtual crash using a control chart methodology for behavioural measures during a simulated driving task. Tracking error, human back pressure, sitting pressure and horizontal and vertical neck bending angles were measured during the simulated driving task. The time with a high risk of a virtual crash occurred in 9 out of 10 participants. The time interval between the successfully detected point in time with high risk of virtual crash and the point in time of virtual crash ranged from 80 to 324 s. The proposed procedure for predicting the point in time with a high risk of a crash is promising for warning drivers of the state of high risk of crash.

Practitioner Summary: Many fatal crashes occur due to drowsy driving. We proposed a method to predict the point in time with high risk of virtual crash before such a virtual crash occurs. This is done using behavioural measures during a simulated driving task. The effectiveness of the method is also demonstrated.     

A decision support methodology with risk assessment on prediction of terrorism insurgency distribution range radius and elapsing time: An empirical case study in Thailand

The objectives of this research are to design and develop a practical decision support methodology with efficient prediction tool and risk assessment analysis of a terrorism insurgency situation. The proposed methodology consists of two main parts as: (1) the prediction modelling and (2) risk assessment analysis. The Improvised Explosive Device (IED) incidents from 2007 to 2013 in the capital district of Yala province, the southern part of Thailand, are collected and generated to the methodology as a case study implementation. The proposed methodology is capable of indicating and illustrating the risk assessment prediction results of terrorism insurgency incidents. Furthermore, the demonstration of the Explosive Ordnance Disposal Mobile Unit (EODMU) based upon a Risk Assessment Radar Chart is investigated. In practical terms of applying the proposed methodology, the Thai Government can concentrate on a critical operation zone under a Risk Assessment Radar Chart, resulting in a more accurate operation and leading to a much lower number of casualties.     

Naming the pain in requirements engineering: A design for a global family of surveys and first results from Germany

ContextFor many years, we have observed industry struggling in defining a high quality requirements engineering (RE) and researchers trying to understand industrial expectations and problems. Although we are investigating the discipline with a plethora of empirical studies, they still do not allow for empirical generalisations.ObjectiveTo lay an empirical and externally valid foundation about the state of the practice in RE, we aim at a series of open and reproducible surveys that allow us to steer future research in a problem-driven manner.MethodWe designed a globally distributed family of surveys in joint collaborations with different researchers and completed the first run in Germany. The instrument is based on a theory in the form of a set of hypotheses inferred from our experiences and available studies. We test each hypothesis in our theory and identify further candidates to extend the theory by correlation and Grounded Theory analysis.ResultsIn this article, we report on the design of the family of surveys, its underlying theory, and the full results obtained from Germany with participants from 58 companies. The results reveal, for example, a tendency to improve RE via internally defined qualitative methods rather than relying on normative approaches like CMMI. We also discovered various RE problems that are statistically significant in practice. For instance, we could corroborate communication flaws or moving targets as problems in practice. Our results are not yet fully representative but already give first insights into current practices and problems in RE, and they allow us to draw lessons learnt for future replications.ConclusionOur results obtained from this first run in Germany make us confident that the survey design and instrument are well-suited to be replicated and, thereby, to create a generalisable empirical basis of RE in practice.     

Effects of the resting time associated with the number of trials on the total and individual finger forces in a maximum grasping task

The repetitive and excessive workload accompanying grip strength- or hand-intensive tasks are often considered to be common causes of work-related upper limb musculoskeletal disorders. For this reason, numerous experimental studies have been performed on maximum grip strength. However, due to an absence of standard guidelines, researchers have adopted different resting times and number of trials suited for their particular research purposes. The effects of resting time and the number of trials on the maximum total grip strength and individual finger forces of 24 participants over 20 trials were investigated. Results showed that the total grip strength and individual finger strengths differed significantly according to the resting time and the number of trials (p < 0.05). Overall, grip strength tended to increase with a reduction in resting time (% reduction: 7.8%, 9.1%, 11.1%, and 13.0% for 3 min, 2 min, 1 min, and 30 s resting time, respectively) as well as with an increase in the number of trials (% reduction: 8%, 10%, 13%, and 16% for 5th, 10th, 15th, and 20th trials). The effects of resting time and the number of trials also showed statistically significant effects on individual finger forces. Regression equations of total grip strength and finger forces with resting time and number of trials were established. These equations were then applied to formulate guidelines for appropriate resting times in experiments based on the number of trials and acceptable reductions in grip strength. Data from this and future studies regarding decreasing grip strength and the contribution of each finger are expected to form the groundwork for ergonomic hand tool design and development.     

A study on the capacity of a ventilation cooling vest with pressurized air in hot and humid environments

Hot and humid working environments exist in civil engineering, exploration, shipping, and so on. Especially in mines and textile workplaces, the air humidity is usually close to saturation. Frontline workers perform physically demanding work, which will make the body sweat greatly and increase the occurrence of heat-related illnesses. The microenvironment under clothing can be improved by a ventilation cooling vest with pressurized air (denoted VCV), and the trunk skin temperature will be decreased. However, the amount of heat that a VCV removes from a working human body in hot and humid environments is unclear. In this study, human experiments were carried out, the ambient temperature was controlled at 30 °C, 32 °C or 34 °C, and the air humidity was 90%. The subjects wore a labor suit (denoted LS) or a VCV, running on a treadmill at 5 km/h or 7.5 km/h. The results showed that the total trunk heat loss was increased by 169–237%, and the cooling power of the VCV was between 79.5 and 97.6 W when wearing the VCV. However, the actual skin wettedness is often less than the calculated value, and the calculated cooling power should be considered the upper limit. The study indicated that the cooling capacity of the VCV increased as the ambient temperature and labor intensity increased, and the heat dissipation of the body also increased.