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The purpose of this study was to investigate the effects of holding external loads on postural sway during upright stance across age decades. Sixty-five healthy adults (females, n = 35), aged 18-80 years were assessed in four conditions; (1) standing without holding a load, holding a load corresponding to 5% body mass in the (2) left hand, (3) right hand and (4) both hands. The centre of pressure (COP) path length and anteroposterior and mediolateral COP displacement were used to indirectly assess postural sway. External loading elicited reductions in COP measures of postural sway in older age groups only (P < 0.05). No changes were observed in younger or intermediate aged adults (P > 0.05). Holding external loads during standing is relevant to many activities of daily living (i.e. holding groceries). The reduction in postural sway may suggest this type of loading has a stabilising effect during quiet standing among older adults. [ABSTRACT FROM AUTHOR]

This paper highlights a preference evaluation methodology for text entry methods in a touch keyboard smartphone using analytic network process (ANP). Evaluation of text entry methods in literature mainly considers speed and accuracy. This study presents an alternative means for selecting text entry method that considers user preference. A case study was carried out with a group of experts who were asked to develop a selection decision model of five text entry methods. The decision problem is flexible enough to reflect interdependencies of decision elements that are necessary in describing real-life conditions. Results showed that QWERTY method is more preferred than other text entry methods while arrangement of keys is the most preferred criterion in characterizing a sound method. Sensitivity analysis using simulation of normally distributed random numbers under fairly large perturbation reported the foregoing results reliable enough to reflect robust judgment. The main contribution of this paper is the introduction of a multi-criteria decision approach in the preference evaluation of text entry methods. [ABSTRACT FROM AUTHOR]

This paper focuses on the comparative assessment of comfort and discomfort (hereafter, (dis-)comfort) for aircraft seating. Subjective and objective data of seating (dis-)comfort were collected during an experiment involving 20 volunteers who tested 3 aircraft double-seats in upright and reclined position. In order to minimize experimental uncertainty due to well-known noise factors (i.e. patterns of discomfort during the work week and during the work day, order of evaluation, inter-individual differences), experimental trials were performed according to a crossover design. Statistical data analysis aimed mainly at investigating (dis-)comfort differences across seat conditions; gender-based differences in perceived discomfort on different body parts; effect of sitting duration on perceived discomfort on different body parts. The experimental results show that differences across seat conditions impacted differently on perceived discomfort depending on gender, body parts and sitting duration. No significant differences in perceived discomfort across gender were evident for the lightweight seat in both upright and reclined positions. On the contrary, for both baseline configurations, perceived discomfort at head and neck areas was higher for males than for females. For all seat conditions, participants experienced a significant worsening of perceived comfort over time at shoulders, back, sacrum and thighs and, in addition, at upper body area (i.e. neck, arm and forearm) and knees only for seats in reclined position. [ABSTRACT FROM AUTHOR]

Appropriate visual display terminal (VDT) location is a subject of ongoing debate. Generally, visual strain is associated with higher placement, and musculoskeletal strain is associated with lower placement. Seeking resolution of the debate, this paper provides a comparison of results from previous lab-based monitor placement studies to recommendations and outcomes from viewing preference and neutral posture studies. The paper then presents results from a field study that addressed two outstanding issues: Does monitor placement in a workplace elicit postures and discomfort responses similar to those seen in laboratory settings? Results showed placements in the workplace elicited postures similar to those in lab studies. Additionally, preferred VDT location generally corresponded to the location in which less neck discomfort was reported, though that trend requires further investigation. Overall, there seems to be consistent evidence to support mid-level or somewhat higher placement, as a rule-of-thumb, considering preferred gaze angle and musculoskeletal concerns. However, optimal placement may be lower for some individuals or tasks. [ABSTRACT FROM AUTHOR]

This paper examines the utility of prospective memory as a secondary task. For this purpose, the results of seven experiments were analysed to evaluate the sensitivity of prospective memory, making a direct comparison with another secondary task (reaction time). Both tasks were used as subsidiary elements in a complex task environment, the design of which was based on the micro-world research paradigm. The results indicated that prospective memory was slightly more vulnerable to variations in experimental conditions than was reaction time. The paper concludes that, overall, prospective memory appears to be a suitable secondary task. This is partly attributed to the element of self-initiation, which is a feature of some prospective memory tasks. It is recommended to use time-based and pulse-based prospective memory tasks since they seem to be the more sensitive. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) body scanners have the potential to evaluate changes to the human form through different clothing configurations, the use of protective equipment, or the effects of medical interventions. To achieve this, scans of an individual need to be superimposed for each experimental condition. The literature highlights that one of the limiting factors is postural variability. This paper describes a newly developed 'positioning aid' that stabilises the posture during the scanning process and is invisible on scans. The results of a study evaluating the efficacy of the positioning aid showed that it reduces postural variability for all body parts in lateral and longitudinal directions. A reference test with a rigid mannequin indicated that the 'technical' variability due to the scanner hardware and software significantly contributes to the residual variability. Furthermore, the study showed that the newly developed positioning aid overall increased the precision of the software-assisted extraction of body dimensions. [ABSTRACT FROM AUTHOR]

Objective: Complex medical devices such as infusion pumps are increasingly being used in patients' homes with little known about the impact on patient safety. Our aim was to better understand the risks to patient safety in this situation and how these risks might be minimised, by reference to incident reports.Design: We identified 606 records of incidents associated with infusion devices that had occurred in a private home and were reported to the UK National Reporting and Learning Service (2005-2015 inclusive). We used thematic analysis to identify key themes.Results: In this paper we focus on two emergent themes: detecting and diagnosing incidents; and locating the patient, lay caregivers and their family in incident reports. The majority of incidents were attributed to device malfunction, and resulted in the patient being under-dosed. Delays in recognising and responding to problems were identified, alongside challenges in identifying the cause. We propose a process model for fault diagnosis and correction. Patients and caregivers did not feature strongly in reports; we highlight how the device is in the home but of the care system, and propose an agent model to describe this; we also identify ways of mitigating this disjoint.Conclusion: Devices need to be appropriately tailored to the setting in which they are employed, and within a system of care that ensures they are used optimally and safely. Suggested features to improve patient safety include devices that can provide better feedback to identify problems and support resolution, alongside greater monitoring and technical support by care providers for both patients and frontline professionals. The proposed process and agent models provide a structure for reviewing safety and learning from incidents in home health care. [ABSTRACT FROM AUTHOR]

This is the first in a two-part series of papers dealing with the area of assessing human errors in high risk complex systems. This first paper outlines thirty-eight approaches of error identification, categorising them into types of error identification approach. The paper then reviews these techniques with respect to a broad range of criteria. Viable and non-viable techniques are identified. Trends and research needs are also noted. The second paper proposes a framework or tool-kit approach to Human Error Identification, and presents a prototype methodology to show what such a framework approach would look like in practice, for the nuclear power domain. [ABSTRACT FROM AUTHOR]

Recent evidence suggests that musculoskeletal disorders (MSDs) may be the result of a fatigue failure process in affected tissues. This paper describes a new low back exposure assessment tool (the Lifting Fatigue Failure Tool [LiFFT]), which estimates a "daily dose" of cumulative loading on the low back using fatigue failure principles. Only three variables are necessary to derive the cumulative load associated with a lifting task: the weight of the load, the maximum horizontal distance from the spine to the load, and the number of repetitions for tasks performed during the workday. The new tool was validated using two existing epidemiological databases: the Lumbar Motion Monitor (LMM) database, and a database from a U.S. automotive manufacturer. The LiFFT cumulative damage metric explained 92% of the deviance in low back disorders (LBDs) in the LMM database and 72-95% of the deviance in low back outcomes in the automotive database (depending on the outcome measure). Thus, LiFFT is practitioner friendly and its cumulative damage metric highly related to low back outcomes. [ABSTRACT FROM AUTHOR]

Construction jobs are more labor-intensive compared to other industries. As such, construction workers are often required to exceed their natural physical capability to cope with the increasing complexity and challenges in this industry. Over long periods of time, this sustained physical labor causes bodily injuries to the workers which in turn, conveys huge losses to the industry in terms of money, time, and productivity. Various safety and health organizations have established rules and regulations that limit the amount and intensity of workers' physical movements to mitigate work-related bodily injuries. A precursor to enforcing and implementing such regulations and improving the ergonomics conditions on the jobsite is to identify physical risks associated with a particular task. Manually assessing a field activity to identify the ergonomic risks is not trivial and often requires extra effort which may render it to be challenging if not impossible. In this paper, a low-cost ubiquitous approach is presented and validated which deploys built-in smartphone sensors to unobtrusively monitor workers' bodily postures and autonomously identify potential work-related ergonomic risks. Results indicates that measurements of trunk and shoulder flexions of a worker by smartphone sensory data are very close to corresponding measurements by observation. The proposed method is applicable for workers in various occupations who are exposed to WMSDs due to awkward postures. Examples include, but are not limited to industry laborers, carpenters, welders, farmers, health assistants, teachers, and office workers. [ABSTRACT FROM AUTHOR]

This paper proposed a colored petri nets based workload evaluation model. A formal interpretation of workload was firstly introduced based on the process that reflection of petri nets components to task. A petri net based description of Multiple Resources theory was given by comprehending it from a new angle. A new application of VACP rating scales named V/A-C-P unit, and the definition of colored transitions were proposed to build a model of task process. The calculation of workload mainly has the following four steps: determine token's initial position and values; calculate the weight of directed arcs on the basis of the rules proposed; calculate workload from different transitions, and correct the influence of repetitive behaviors. Verify experiments were carried out based on Multi-Attribute Task Battery-II software. Our results show that there is a strong correlation between the model values and NASA -Task Load Index scores (r=0.9513). In addition, this method can also distinguish behavior characteristics between different people. [ABSTRACT FROM AUTHOR]

Thermoregulation models of the human body have been widely used in thermal comfort studies. The existing models are complicated and not fully verified for application in China. This paper presents a simplified thermoregulation model which has been statistically validated by the predicted and measured mean skin temperature in warm environments, including 21 typical conditions with 400 Chinese subjects. This model comprises three parts: i) the physical model; ii) the controlled system; and iii) the controlling system, and considers three key questions formerly ignored by the existing models including: a) the evaporation efficiency of regulatory sweat; b) the proportional relation of total skin blood flow and total heat loss by regulatory sweating against body surface area; and c) discrepancies in the mean skin temperatures by gender. The developed model has been validated to be within the 95% confidence interval of the population mean skin temperature in three cases. [ABSTRACT FROM AUTHOR]

Overhead guide sign visibility must increase to improve driver safety on roadways. Two methods increase overhead guide sign visibility: sign illumination and use of retroreflective sheeting materials. This paper compares three types of retroreflective sheeting: Engineering Grade (type I), Diamond Grade (type XI), and High Intensity (type IV). A field experiment was conducted at night using licensed drivers to determine the optimum retroreflective sheeting material that increases sign visibility and legibility. Results showed that, of the three types of retroreflective sheeting, Diamond Grade (type XI) sheeting requires minimum illuminance to be visible, followed by High Intensity (type IV) sheeting. Cost analysis, including labor, maintenance, and material cost components of the three retroreflective sheeting materials, showed that High Intensity (type IV) could increase sign visibility and legibility at night for Departments of Transportation with limited budgets, consequently increasing driver safety on roadways. [ABSTRACT FROM AUTHOR]

During the design of Human-Computer Interaction (HCI) systems, the creation of visual artefacts forms an important part of design. On one hand producing a visual artefact has a number of advantages: it helps designers to externalise their thought and acts as a common language between different stakeholders. On the other hand, if an inappropriate visualisation method is employed it could hinder the design process. To support the design of HCI systems, this paper reviews the categorisation of visualisation methods used in HCI. A keyword search is conducted to identify a) current HCI design methods, b) approaches of selecting these methods. The resulting design methods are filtered to create a list of just visualisation methods. These are then categorised using the approaches identified in (b). As a result 23 HCI visualisation methods are identified and categorised in 5 selection approaches (The Recipient, Primary Purpose, Visual Archetype, Interaction Type, and The Design Process). [ABSTRACT FROM AUTHOR]

To design accessibly, designers need good, relevant population data on visual abilities. However, currently available data often focuses on clinical vision measures that are not entirely relevant to everyday product use. This paper presents data from a pilot survey of 362 participants in the UK, covering a range of vision measures of particular relevance to product design. The results from the different measures are compared, and recommendations are given for relative text sizes to use in different situations. The results indicate that text needs to be 17-18% larger for comfortable rather than perceived threshold viewing, and a further 20% larger when users are expected to wear their everyday vision setup rather than specific reading aids. [ABSTRACT FROM AUTHOR]

Helmet safety benefits are reduced if the headgear is poorly fitted on the wearer's head. At present, there are no industry standards available to assess objectively how a specific protective helmet fits a particular person. A proper fit is typically defined as a small and uniform distance between the helmet liner and the wearer's head shape, with a broad coverage of the head area. This paper presents a novel method to investigate and compare fitting accuracy of helmets based on 3D anthropometry, reverse engineering techniques and computational analysis. The Helmet Fit Index (HFI) that provides a fit score on a scale from 0 (excessively poor fit) to 100 (perfect fit) was compared with subjective fit assessments of surveyed cyclists. Results in this study showed that quantitative (HFI) and qualitative (participants' feelings) data were related when comparing three commercially available bicycle helmets. Findings also demonstrated that females and Asian people have lower fit scores than males and Caucasians, respectively. The HFI could provide detailed understanding of helmet efficiency regarding fit and could be used during helmet design and development phases. [ABSTRACT FROM AUTHOR]

Abstract: The release of the Institute of Medicine () report “To Err is Human”, brought attention to the problem of medical errors, which led to a concerted effort to study and design medical error reporting systems for the purpose of capturing and analyzing error data so that safety interventions could be designed. However, to make real gains in the efficacy of medical error or event reporting systems, it is necessary to begin developing a theory of reporting systems adoption and use and to understand how existing theories may play a role in explaining adoption and use. This paper presents the results of a 9-month study exploring the barriers and facilitators for the design of a statewide medical error reporting system and discusses how several existing theories of technology acceptance, adoption and implementation fit with many of the results. In addition we present an integrated theoretical model of medical error reporting system design and implementation. [Copyright &y& Elsevier]

This paper presents the results of an anthropometric survey conducted on male and female Mexican primary school children age 6-11 years in the metropolitan area of the city of Guadalajara. A set of 50 body dimensions was taken based on international standards. The sample consisted of 4758 children (boys and girls). The anthropometric measurements were compared to those of American, Cuban and Mexican children. The results indicate that the body dimensions of Mexican children from this study are different from those of American, Cuban, and other Mexican children, probably due to ethnic differences and the time lapse between the different studies. It is considered that the 50 parameters are necessary for the design of school furniture, fittings and equipment in order to minimize musculoskeletal, visual, and circulatory problems resulting from using those badly designed elements. [ABSTRACT FROM AUTHOR]

This paper describes ergonomic issues raised during a project to provide a replacement real-time bus route control system to a large public transport company. Task and system analyses highlighted several deficiencies in the original system architecture, the human-machine interfaces and the general approach to system management. The eventual live prototype replaced the existing original system for a trial evaluation period of several weeks. During this period a number of studies was conducted with the system users in order to measure any improvements the new system, with its ergonomic features, produced over the old. Importantly, the results confirmed that (a) general responsiveness and service quality were improved, and (b) users were more comfortable with the new design. We conclude with a number of caveats which we believe will be useful to any group addressing technology impact in a large organisation. [ABSTRACT FROM AUTHOR]

Drivers' non-compliance with rules is a prominent factor in collisions with trains at railway level crossings. Road user impatience and frustration has been identified as an underlying factor in non-compliance and can be characterised as a specific risk factor. However, research on non-compliance related to waiting times and driver inconvenience lacks in the literature. This paper, therefore, seeks to enhance the currently limited understanding of the relationship between waiting times and risky driver behaviour. An Advanced Driving Simulator was used to obtain objective measures of level crossing non-compliance. Subjective measures on driver frustration and decision-making processes were also collected. Sixty participants completed six driving tasks each, with the tasks varying in terms of traffic conditions, number of trains and associated waiting times. This study shows that increased waiting times result in higher levels of frustration and an increased likelihood of risky driving behaviour, particularly for waiting times longer than 3 min. Non-compliance included entering the activated crossing before boom gates are down, entering the crossing after the train passage but before signals are deactivated, stopping/reversing on the crossing. Subjective data revealed that participants did not comply with level crossing rules due to factors including time pressure, impatience/frustration and low perceived risk. The results suggest that, where possible, waiting times should be standardised at values lower than 3 min to reduce the likelihood of risky road user behaviour. [ABSTRACT FROM AUTHOR]