Applying the sustainable system-of-systems framework: wastewater(s) in a rapidly urbanising South African settlement

Addressing wastewater infrastructure needs in urban informal settlements must simultaneously address legacies of past failures, current aspirations and constraints, as well as increasingly changing needs related to global environmental change. This study applied the Sustainable System-of-Systems framework for ergonomics and human factors to gain a better understanding of how small in-situ constructed wetlands could be a form of greywater treatment infrastructure in an informal settlement. Using 24 months of interviews, surveys, workshops and photo-ethnographic observations, we identified that the rapidly changing nature of parent (e.g. residency transience and land ownership) and sibling (e.g. housing and drinking water) systems put pressure on the target wetland system to adapt, often decreasing its capacity to deliver the service of water cleaning. Greywater treatment was not a common goal among stakeholders involved in the nested hierarchy system which likely contributed to the constructed wetlands needing to adapt to remain relevant.Practitioner summary: The value of the Sustainable Systems-of-Systems framework for ergonomics/human factors professionals in determining the sustainability of an ergonomics/human factors intervention is demonstrated using a greywater treatment system case study for an urban informal settlement. Understanding the variety of stakeholder goals and the pace of change in related systems was key to a sustainable intervention.

Quantifying the qualitative: exploring epistemic network analysis as a method to study work system interactions

Studying interactions faces methodological challenges and existing methods, such as configural diagramming, have limitations. This work demonstrates Epistemic Network Analysis (ENA) as an analytical method to construct configural diagrams. We demonstrated ENA as an analytical tool by applying this method to study dementia caregiver work systems. We conducted 20 semi-structured interviews with caregivers to collect caregiving experiences. Guided by the Patient Work System model, we conducted a directed content analysis to identify work system components and used ENA to study interactions between components. By using ENA to create configural diagrams, we identified five frequently occurring interactions, compared work system configurations of caregivers providing care at home and away from home. Although we were underpowered to determine statistically significant differences, we identified visual and qualitative differences. Our results demonstrate the capability of ENA as an analytical method for studying work system interactions through configural diagramming. Practitioner summary: A new methodology, Epistemic Network Analysis (ENA), was presented to better support the study of work system interactions through configural diagramming. ENA was applied to qualitative data to demonstrate the capabilities of this method to construct configural diagrams of the work system. This study successfully demonstrated that ENA can visually represent and describe work system configurations.

Agreement between observed and interview-based exposure to ergonomics factors for the upper extremities in employees of a package sorting plant

Aim of the study was to estimate agreement between observational and interview-based exposure to ergonomic factors at work. Thirty-two male workers employed in a logistics hub were interviewed through the OCRA check-list on exposure to ergonomic factors in one of six work tasks. Observations of workers in each work task, based on the same OCRA check-list, were used to assess exposure in that task. Agreement between observed and interview-based scores of the check-list OCRA index, as well as of frequency and posture, was estimated both at individual and task group level through the Intraclass Correlation Coefficient (ICC). At work task level, high concordance was found between observed and interview-based scores for all the exposures examined, while at the individual level agreement was moderate. These results suggest that exposure assessment through interviews based on the OCRA check-list is a valid method, which could be used as a workstation screening tool. Practitioner summary: The study aimed to evaluate agreement between observational and interview-based exposure to ergonomic factors at work, assessed through the OCRA check-list on 32 male workers. Agreement was found at least moderate, suggesting that interview-based exposure assessed through the OCRA check-list could be used as a proxy of observations for workstation screening. Abbreviations: ART: assessment of repetitive tasks; CI: confidence intervals; EAWS: European assembly worksheet; ICC: intraclass correlation coefficient; ISO: International Standards Organization; OCRA: occupational repetitive actions; ULRA: upper limb risk assessment; WUEMSDs: work-related upper extremity musculoskeletal disorders.

Superior side sound localisation performance in a full-chassis driving simulator

Alerts presented through the auditory modality improve drivers' crash avoidance performance in driving simulations, but drivers' ability to accurately localise the source of the auditory alerts is understudied. Because the results of driving simulation studies may hinge on assumptions that sound locations are accurately perceived by drivers, this study used a sound localisation task in a full-chassis driving simulator. Twenty-nine participants engaged in a sound localisation task while seated in the driving simulator. Performance was assessed by sound localisation accuracy, relative directional error, and participant confidence across seven sound sources surrounding the simulator. Performance was best when sounds were presented in left and right cardinal regions, and poorest when presented from the front and rear. Participants were less confident in their localisation judgments when sounds were presented from the rear. Practitioner summary: Drivers' ability to accurately localise auditory alerts is understudied. Participants performed an auditory localisation task with external sounds while seated in a full-chassis driving simulator. Participants were better detecting sounds from the sides instead of the front and rear. This has implications for external auditory alarms during driving. Abbreviations: ANOVA: analysis of variance; dB: decibel; f: frequency; Hz: hertz; LHD: left hand drive; ms: milliseconds; RTI: realtime technologies; s: seconds; SPL: sound pressure level.

Mapping the territory of renal care: a formative analysis of the cognitive work involved in managing acute kidney injury

The design and evaluation of healthcare work systems requires an understanding of the cognitive work involved in healthcare tasks. Previous studies suggest that a formative approach would be particularly useful to examine healthcare activities for this purpose. In the present study, methods from cognitive work analysis and cognitive task analysis are combined in a formative examination of managing acute kidney injury, an activity that occurs across primary and secondary healthcare settings. The analyses are informed by interviews with healthcare practitioners and a review of practice guidelines. The findings highlight ways in which the task setting influenced practitioners' activity, and ways in which practitioners approached the activity (for example, how they used data to make decisions). The approach taken provided a rich understanding of the cognitive work involved, as well as generating suggestions for the design of work systems to support the clinical task. Practitioner summary: Healthcare tasks often require decision-making in complex and dynamic circumstances, potentially involving collaboration across different practitioner roles and locations. We demonstrate the use of a formative analysis to understand the cognitive work in managing a clinical syndrome across primary and secondary care settings, and consider the implications for work design.

Digital Human Modeling in the Occupational Safety and Health Process: An Application in Manufacturing

Digital human modeling (DHM) and simulation software has been identified as an effective tool for evaluating work tasks and design alternatives without requiring the expense of physical mock-ups and production trials. Despite recent commercial advancements and a broader availability of DHM platforms, the peer-reviewed scientific literature lacks sufficient demonstration of the application of DHM software within an occupational safety and health process for mitigating exposures to physical risk factors in a real work environment. We describe the implementation of a commercially-available DHM platform as a component of an occupational safety and health process in a manufacturing environment over the course of one year. Success stories, challenges, and practical recommendations are discussed.

Systems scenarios: a tool for facilitating the socio-technical design of work systems

The socio-technical systems approach to design is well documented. Recognising the benefits of this approach, organisations are increasingly trying to work with systems, rather than their component parts. However, few tools attempt to analyse the complexity inherent in such systems, in ways that generate useful, practical outputs. In this paper, we outline the 'System Scenarios Tool' (SST), which is a novel, applied methodology that can be used by designers, end-users, consultants or researchers to help design or re-design work systems. The paper introduces the SST using examples of its application, and describes the potential benefits of its use, before reflecting on its limitations. Finally, we discuss potential opportunities for the tool, and describe sets of circumstances in which it might be used. Practitioner Summary: The paper presents a novel, applied methodological tool, named the 'Systems Scenarios Tool'. We believe this tool can be used as a point of reference by designers, end-users, consultants or researchers, to help design or re-design work systems. Included in the paper are two worked examples, demonstrating the tool's application.

The reliability of the Extra Load Index as a measure of relative load carriage economy

The aim of this study was to measure the reliability of the extra load index (ELI) as a method for assessing relative load carriage economy. Seventeen volunteers (12 males, 5 females) performed walking trials at 3 km·h^-1, 6 km·h^-1 and a self-selected speed. Trial conditions were repeated 7 days later to assess test-retest reliability. Trials involved four 4-minute periods of walking, each separated by 5 min of rest. The initial stage was performed unloaded followed in a randomised order by a second unloaded period and walking with backpacks of 7 and 20 kg. Results show ELI values did not differ significantly between trials for any of the speeds (p = 0.46) with either of the additional loads (p = 0.297). The systematic bias, limits of agreement and coefficients of variation were small in all trial conditions. We conclude the ELI appears to be a reliable measure of relative load carriage economy. Practitioner Summary: This paper demonstrates that the ELI is a reliable measure of load carriage economy at a range of walking speeds with both a light and heavy load. The ELI, therefore, represents a useful tool for comparing the relative economy associated with different load carriage systems.

A long-term evaluation of the stage of change approach and compensable injury outcomes - a cluster-randomised trial

This study investigated the long-term injury outcomes for workers in companies from a range of industries which had been randomly allocated to receive ergonomics interventions tailored according to the stage of change (SOC) approach or standard ergonomics advice. Differences in compensable injury outcomes between the groups were analysed using logistic regression models. Questionnaire results from face-to-face interviews to assess musculoskeletal pain and discomfort (MSPD), job satisfaction and other factors were also analysed. Although not significant at the 0.05 level, after adjusting for workgroup clustering, workers in receipt of tailored advice were 55% (OR = 0.45, 95% CI = 0.19-1.08) less likely to report a compensable injury than those in receipt of standard ergonomics advice. Workload, job satisfaction and MSPD were significantly correlated with injury outcomes. The observed outcomes support the potential value of the SOC approach, as well as highlighting the need to consider workload, job satisfaction and MSPD when planning injury prevention programmes. Practitioner Summary: This study investigated compensable injury outcomes for workers who had received ergonomics advice tailored according to the stage of change (SOC) approach compared with standard ergonomics advice. The results support the potential value of the SOC approach and highlight the need to consider workload, job satisfaction and musculoskeletal pain and discomfort when planning injury prevention interventions.

Effect of noise on comfort in open-plan offices: application of an assessment questionnaire

Open-plan offices account for 60% of French office workspaces. The noise levels recorded in this type of environment are much lower than those encountered in industrial workplaces. Nevertheless, surveys show that noise is considered by employees as the main source of discomfort. A first questionnaire dedicated to noise discomfort was produced in 2013 and tested on a panel made up of 217 people working in 7 French companies. Today, it also makes it possible to address the issues of fatigue related to ambient sound, but above all, the survey aims to study the differences in how ambient noise is perceived depending on the type of open-plan office. On the basis of that new version, a second survey has been conducted in 23 open-plan offices, making it possible to collect the responses from 617 employees. Most of the results of the first survey have been confirmed, with an increase in the significance of the statistical analyses. Moreover, French Standard NF S 31-199, which is currently being drafted, establishes a typology of open-plan office spaces according to the types of work done in them. Based on this typology, it appears that when dealing with the impact on noise on workers, a distinction has to be made between the types of open plan offices. Practitioner Summary: Surveys conducted in open-plan offices show that noise is considered by employees as the main source of discomfort even if the noise recorded in this type of environment is not hazardous. This work presents the result of a large survey dedicated to noise discomfort conducted in 23 open-plan offices.

On the paradoxical decrease of self-reported cognitive failures with age

The science of Human Factors and Ergonomics (HF/E) often relies on self-report. This is a cause for concern because subjective methods are inherently susceptible to bias. Here, we present, examine and discuss a puzzling association between age and self-reported cognitive failures as assessed with Broadbent's Cognitive Failures Questionnaire (CFQ). Despite many well-established age-associated forms of cognitive decline, older persons actually report almost equivalent, or even less, cognitive failures on the CFQ than younger persons. Our present analysis indicates that this paradox may be resolved through the fact that people show age-related learning/adaptation/compensation and by the observation that the CFQ measures peoples' beliefs with respect to an individually idiosyncratic reference. Yet, at the heart of the paradox may be the idea that people cannot remember their own cognitive failures, pointing to even greater concerns with all forms of subjective self-report and its use in HF/E. Practitioner Summary: Scientists and practitioners often try to understand and improve human performance with the help of self-report questionnaires. Our paper discusses the validity of self-reported errors measured with the Cognitive Failures Questionnaire (CFQ). We look to resolve the curious paradox that older persons tend to report fewer failures than younger persons do.

Noise effect on comfort in open-space offices: development of an assessment questionnaire

It is currently accepted that noise is one of the most important annoyance factors in open-space offices. However, noise levels measured in open spaces of the tertiary sector rarely exceed 65 dB(A). It, therefore, appears necessary to develop a tool that can be used to assess the noise environment of these offices and identify the parameters to be taken into consideration when assessing the noise annoyance. This article presents a questionnaire to be filled by people working in such environment, and a case study in different open plan offices. The majority of the 237 respondents consider that the ambient noise level in their environment is high and that intelligible conversations between their colleagues represent the main source of noise annoyance. This annoyance was significantly correlated with their evaluation of sound intensity, which could not be represented by A-weighted level measurements.

Determination of the precision and accuracy of morphological measurements using the Kinect™ sensor: comparison with standard stereophotogrammetry

The recent availability of the Kinect™ sensor, a low-cost Markerless Motion Capture (MMC) system, could give new and interesting insights into ergonomics (e.g. the creation of a morphological database). Extensive validation of this system is still missing. The aim of the study was to determine if the Kinect™ sensor can be used as an easy, cheap and fast tool to conduct morphology estimation. A total of 48 subjects were analysed using MMC. Results were compared with measurements obtained from a high-resolution stereophotogrammetric system, a marker-based system (MBS). Differences between MMC and MBS were found; however, these differences were systematically correlated and enabled regression equations to be obtained to correct MMC results. After correction, final results were in agreement with MBS data (p = 0.99). Results show that measurements were reproducible and precise after applying regression equations. Kinect™ sensors-based systems therefore seem to be suitable for use as fast and reliable tools to estimate morphology. Practitioner Summary: The Kinect™ sensor could eventually be used for fast morphology estimation as a body scanner. This paper presents an extensive validation of this device for anthropometric measurements in comparison to manual measurements and stereophotogrammetric devices. The accuracy is dependent on the segment studied but the reproducibility is excellent.