Object: Assembly lines are one of the essential parts of manufacturing systems that influence the overall cost and efficiency. The productivity of human resource in assembly lines directly affects the efficiency of the lines in practice.
Object: Improper workplace design is one of the significant reasons for occupational accidents and injuries in labor-intensive production sites. Inadequate and incomplete working environments ignoring ergonomic factors at the planning level create persistent psychical disorders, increase mistakes and accident rates and decrease work productivity. Enhancement of the compliance between worker and task is a crucial step for improving productivity.
Objective: A direct comparison of different kinds of scale formats of ratings of comfort and of mood states as well as their relation to the cardiovascular response was the objective. It was expected that activation-related scales are associated with physiological measures and that comfort scales and ratings of mood states would give complementary information on the impact of environmental conditions.
Background: Emergency Department (ED) crowding is a frequent problem that causes prolonged waiting and increased risk of adverse events. While the number of daily and monthly patient arrivals can be forecasted with good accuracy, ED clinicians need hourly forecasts in their ongoing scheduling and rescheduling of their work.
The aim of this review is to examine the effect of extended working hours and shift work on occupational injuries. A calculation based on five studies shows that the risk of occupational injury during afternoon shifts was 6% lower than that during morning shifts. The same kind of calculation showed that the risk of occupational injury during night shifts was 15% lower than during morning shifts. A review of twelve studies showed that the risk of occupational injury was 15% higher for 10-hour working days compared to 8-hour working days. On the other hand, working 12-hour days increased the risk of occupational injury by 38%. When working more than 12 hours per day, four studies showed a 147% increase in involvement in occupational injury. The results of this review showed that shift work considerably increased the risk of occupational injury in the USA, but not in India and Singapore. Extended working hours was related to elevated risk of occupational injury. Thus shift work and long work hours did not suit for all employees.
Objective: To investigate the influence of three different types of shoe models frequently worn at home, including an open heel shoe model, on gait parameters that are associated with fall risk in older persons.
Crowding is common in emergency departments (EDs) and increases the risk of medical errors, patient dissatisfaction, and clinician stress. The aim of this study is to investigate patterns in patient visits and bottlenecks in ED work in order to discuss the prospects of visualizing such patterns to help manage crowding. We analyze two years of data from a Danish ED for patterns in the patient visits and interview six clinicians from the ED about bottlenecks in their work. The hour of the day explains 50% of the variance in the number of patient arrivals. In addition, there are weekly and yearly patterns in patient arrivals. With respect to the flow of patients through the ED, length of stay increases from low to medium triage levels and then decreases from medium to high triage levels. Also, length of stay increases with patient age. The bottlenecks in the work in the ED relate to patient input (mornings, boom days), patient throughput (staff work hours, linear workflows, manual data entry, overview of patient progress, personal competences), and patient output (no admissions at night, scheduling patient transfers, home transports). The patterns in patient arrivals and length of stay capture factors important to the evolving balance between the demand for ED services and the available resources. Visualization of the patterns, thus, appears a promising tool in managing ED crowding. However, visualizations presuppose reliable data and are expected by the clinicians to be accurate and prognostic. We propose three visualizations.
Heart rate variability (HRV) is an established indication of cardiovascular regulation and is often not only considered in relation to health, but also to subjective aspects of perceived affect. However, as the various HRV parameters are not identical but interrelated, they vary in regard to different aspects of every-day moods, stress, and depression. Therefore it is suggested that those HRV parameters would discriminate perceived affect. This study compares the relationship of HRV parameters to aspects of every-day affect. In 60 persons heart rate (HR) and HRV measures of time domain parameters (including pNNxx parameters), frequency domain parameters, and relative parameters (from twenty-four hour electrocardiography recordings) were investigated in relation to perceived stress (PSQ), anxiety (STAI-T), depression (BDI-II), general well-being (GWBS), and traits of every-day moods (TRIM-T). Results showed that HRV parameters were correlated to most subjective measures (PSQ, BDI-II, GWBS, and good mood and relaxation in TRIM-T). Low pNNxx parameters (pNN10 - pNN40) correlated negatively with stress and depression and positively with well-being, whereas high pNNxx parameters (pNN125 - pNN175), SDNN, ultralow frequency (ULF), and total power (TP) were in particular correlated to good mood. Furthermore, results showed that slow rhythms, in particular ULF, were correlated to positive affect (good mood, relaxation), but not to negative affect (stress, anxiety, depression). Correlations of cardiovascular activity with well-being are less pronounced, indicating that the construct of well being may be seen as a mixture of positive affect and low stress - and is in general less related to cardiovascular activity than stress and/or good mood. For relative HRV measures, in particular for log LF/HF (which is often interpreted as a measure of autonomic balance), no correlations with every-day affect were observed. Results further indicate that the time domain parameters of pNNxx (in particular pNN10 - pNN40 vs. pNN125 - pNN175) are differentially related to negative/positive affect, contrary to heart rate, and may therefore be considered as an objective indication of affect.
As technology systems have become more complex, so it is increasingly difficult for human operators to comprehend how the system is behaving.There is a need to better understand the causes of human-error in the context of the situational variables.The specific case under examination is the process of landing an aircraft.This paper applies a production engineering perspective.By production-process, we refer to the set of actions that are necessary to move a system from one state to a desired new state.Such processes involve mechanisms for taking inputs and converting them to the desired outputs, under certain controls and constraints.Human error is thus treated as a constraint on the processes.A novel process methodology is developed to represent how technical systems, situational variables, external factors, and human error evolve over time in a process.The applicability is demonstrated with a dataset of case studies.In parallel, a new categorization of human errors is derived for this situation.The method permits cases to be examined individually, and also collectively for patterns.The results show that the initial landing approach is often the point of error initiation.For the specific case of landing accidents the methodology identifies that the failure causality was the lack of attention to establish procedure at the very start of descent, followed by persistent disregard of disconfirmatory evidence at the initial landing approach, especially under conditions of poor visibility.The paper makes a methodological contribution as well as suggesting new insights for how human error occurs at landing.
A healthy work-to-rest ratio during computer work can be an important part of successful preventive workrelated upper limb disorders (WRULD) intervention.Existing break software applications designed to realise such a work-to-rest ratio often possess product features that limit their functionality.Most applications focus on physical relaxation by implementing (micro) breaks into computer work time.Through the emphasis on break time, these applications give the impression that there is no productivity, possibly strengthened by the applications themselves that often visualise the remainder of the break as a slowly decreasing time bar.Moreover, application features such as blocking input devices may counteract cognitive relaxation of computer workers.As imposed physical breaks can be cognitively stressful, especially when deadlines loom, combining physical and cognitive relaxation is a challenge.Actually, research shows that, instead of micro breaks, macro breaks need more attention.It is worthwhile to think of new products for both forms of relaxation within this time span.An idea for a possible product innovation is tested with a small sample and is presented here: a new software application that shows customisable video content during macro breaks.
Meat cutters have long since claimed that knife forces increase with lower meat temperatures.This study was performed to find out what effects the meat temperature has on cutting forces.In addition, the same issue was addressed for pure fat.One hundred and forty four samples of lean meat and of fat respectively were collected and put overnight in one of three refrigerators with temperatures 2, 7 and 12°C, 48 in each.These samples were cut while measuring cutting forces in an Anago KST Sharpness Analyzer machine.The results show that there were no significant differences in knife forces concerning lean meat at the three temperatures.However, the force in pure fat at 2°C was significantly increased by 30% compared to the other temperatures.The forces in fat were generally three times higher than for lean meat, regardless of temperature.
In the framework of the design process of a multimodal 3D simulation environment to support architects' acoustic tasks, we wanted to gain a better understanding of how architects are able to discriminate the sounds using audio and/or visual inputs.This study explores how 2D pictures of rooms do support or impede the auditory evaluation of a space (specifically reverberation).The paper describes an experiment evaluating participants rankings of perceived acoustic reverberation when presented with congruent (coherent) or non-congruent (conflicting) evocative pictures of architectural spaces.We found that the congruent pictures had a positive impact on task performance while the noncongruent pictures had no significant effect.Moreover the effect of the expertise (professional background) of participants was investigated.We found differences between architects and non-architects in the way they performed the task, and they processed reverberation assessments.Taken together, the findings of this study contribute to the question of usefulness of expensive multimodal 3D simulation environment.
Purpose: To compare the work-related and lifestyle factors that support the musculoskeletal health of city bus (CB) drivers and long-distance bus (LDB) drivers, and to find solutions for improving drivers' health. Methods: The participants were 62 bus drivers (aged 34-64 years). Data were gathered using a questionnaire, interviews and a workshop. Altogether 27 CB and 35 LDB drivers responded to the questionnaire, and four drivers were interviewed. Results: The prevalence of musculoskeletal disorders (MSDs) was higher among the CB drivers than among the LDB drivers. The difference was statistically significant (p<0.05) for shoulder pain. The CB drivers more often reported awkward neck postures than the LDB drivers, whereas the LDB drivers performed manual lifting tasks more frequently. The CB drivers were more often exposed to psychosocial load factors and unhealthy lifestyle factors than the LDB drivers. The LDB drivers rated the usability of bus cabs as better than the ratings of the CB drivers. Conclusion: The needs of both LDB and CB drivers must be considered when ergonomic interventions and a holistic approach are applied in bus trade companies. There is a need for ergonomic bus cabs; good maintenance of buses and work equipment; development of work organization; and training on work ergonomics, lifestyle, and work content issues.
The goal of this study was to assess the sensitivity of the heart rate variability measure to variations in task difficulty and drivers' mental workload in agricultural semi-autonomous vehicles.30 young participants with at least one year of tractor driving experience performed steering and implement control and monitoring tasks in a simulator study.Experiments were conducted using the tractor driving simulator (TDS) located in the Agricultural Ergonomics Laboratory at the University of Manitoba.Five levels of automation support from low to high were defined for the implement control and monitoring task.One-half of the participants performed a manual steering task while the other half drove the TDS in automatic steering mode, which only required them to monitor a mapping system and supervise the computer that was performing the steering task.A heart rate monitor was used to record the participants' heart rate.Time and frequency domain parameters of heart rate were analyzed.Some of the time and frequency domain parameters showed some sensitivity to workload variations, however, inconsistencies were observed in the results.The widely used HRV parameter, 0.1 Hz component of HRV, was not sensitive enough to differentiate mental workload levels when the drivers were involved in the task-loop.
The aim of this study was to describe personal assistants' risks for harmful effects in client transfer situations at work.Observation and assessment of their working postures in transfer situations were performed by the Swedish ergonomic regulations concerning "red flags" (AFS 1998:1), by video recordings and by biomechanical analysis.The results showed that among eight home care assistants, four assistants had a low-back posture in client transfer situations which was flexed and/or rotated >60, classified as a harmful effect, a red flag, with a high risk for musculoskeletal workrelated symptoms and disorders and the other four had a risk for harmful effects, yellow flags.The harmful effects were noted in highly flexed and rotated working postures when technical equipment was not used or not possible to use anthropometrically correct.All eight personal assistants´ neck flexion indicated yellow flags, thus there were risks for harmful effect in the neck.
Purpose: To compare ergonomics of an electrically adjustable sit-stand workstation with a traditional workstation in video display unit (VDU) work. Methods: Twelve female workers (aged 27-53 years) participated in this experimental study. Electromyography, wrist postures, subjective assessments, and productivity were used to make the ergonomic comparison. Results: The muscle activity of the right trapezius (p=0.01) and left wrist extensors (p=0.02), extension of the right (p=0.05) and left (p=0.002) wrist, and perceived strain of the arms (p=0.05) were lower and productivity was better (p=0.02) when the workers used a low-sitting, high-sitting, or standing posture at the sit-stand workstation than when using a low-sitting posture at the traditional workstation. In the whole, the subjects were more satisfied (p=0.05) with the sit-stand workstation than with the traditional workstation. Conclusions: Working both in sitting and standing postures was more productive and caused lower strain of the workers' upper limbs than work only in a sitting posture. The electrically adjustable sit-stand workstation offers the possibility to reduce the sedentary behavior and inactivity in VDU work.
The purpose of this study was to compare the traditional height-adjustable shower trolley with the Carevo, a shower trolley with a new design.Compared to the traditional height-adjustable shower trolley, the Carevo has higher side supports, indented curves on the long sides, handles, arrow-shaped ends, and a mattress with a flexible mid-section.In this study four nurses carried out five shower cycles using the traditional height-adjustable shower trolley and five shower cycles using the Carevo.These activities were filmed and analysed by multi-moment sampling at a fixed 3-second interval.Each observation consists of a back score, arm score, leg score and neck score.Results show that working with the Carevo leads to less postural stress on the musculoskeletal system of the caregiver, compared to the traditional heightadjustable shower trolley.There is a 10.2% improvement in time spent in a neutral back position and a 9.4% improvement in the time spent in a neutral neck position.However, the improvements depend on the cut off point: if the cut off point is a flexed back posture of 20°, a 3.0% improvement is found.Although quality of care and comfort was not the subject of this research, we would like to state there is room for improvement, as the patient spends only a small part of the total time on the trolley being showered, which can easily lead to an uncomfortable experience.This quality of care issue seems to be addressed more effectively by new features of the Carevo compared to the traditional height-adjustable shower trolley.
Purpose: Hospital work generates noise.This article investigates the noise level in emergency departments (EDs) to assess the need to address this aspect of the work environment and to investigate whether the replacement of dryerase with electronic whiteboards lowers the noise level. Method:In Study I we measured the noise level at the three coordination centers of an ED while it was still using dryerase whiteboards and after it had switched to electronic whiteboards.In Study II we made similar noise measurements at another ED, supplemented with observation.Results: The median daily equivalent continuous noise levels were 60.0, 55.3, and 55.4 dB(A) at the three coordination centers in Study I and 56.5 dB(A) at the coordination center in Study II.In both studies the noise levels were higher during workdays than weekends and higher during day and evening shifts than during night shifts.The maximum equivalent continuous noise levels across 1 second were above 80 dB(A) at all four coordination centers.At two of the centers above 80 dB(A) noises also occurred at night.After the introduction of electronic whiteboards the noise level was lowered at one ED but unchanged at the other ED.The main noise sources at the ED in Study II were clinicians talking, phones ringing, and equipment being moved around. Conclusion:The noise level at both EDs is above levels previously found to decrease the quality of work, increase the strain on the staff, or both.The transition from dry-erase to electronic whiteboards gave mixed results with respect to alleviating the noise problems.
Purpose: To evaluate the ergonomics and efficacy of five instruments used in dentistry for scaling and root planing.Methods: This experimental study with a comparative cross-sectional design was carried out during a simulated scaling and root planing task.Seven female dentists and one dental hygienist aged 26-58 years participated.Five instruments were evaluated in a subjective analysis of usability and musculoskeletal strain and with measurements of muscular activity, postures of the upper limbs, and work productivity. Results:The instruments with the thickest (diameter of 12-14 mm) silicon handles caused the lowest perceived strain in both the fingers/palm and the thumb.Work productivity was also the best with the thickest silicon handles.Between the instruments, no statistically significant differences were found for the muscular activity of the four muscle groups studied or for the postures of the wrist and upper arm. Conclusions:The design and material of dental instruments can affect perceived comfort and work productivity.In scaling and root planing tasks, instruments with thick silicon handles are more usable, cause lower perceived strain, and are more productive than those with thinner handles.The results of this study can be used to aid dental instruments development and selection.
