Biomedical subjects

R L Shell

Publications and source records attributed to R L Shell.

6 recordsLinked to original sources

PubMed2001

Impact of added rest breaks on the productivity and well being of workers.

The impact of frequent short rest breaks on the productivity and well being of a group of 30 workers in a meat-processing plant was studied. Two rest break schedules were tested, both of which provided 36 min of extra break time over the regular break schedule (30-min lunch and two 15-min breaks). In the first experimental rest break schedule, workers were given 12 3-min breaks evenly distributed over the workday (3-min break for every 27 min of work). In the second schedule, workers were given four 9-min breaks evenly distributed over the workday (9-min break every 51 min of work). Outcome measures included production rate and discomfort and stress ratings. Results showed that neither of the two experimental rest break schedules had a negative effect on production, and the 9-min break schedule improved discomfort ratings for the lower extremities. The workers in the study mostly preferred the 9-min rest break schedule, indicating that workers in general might not as readily accept fragmentation of break time into short, frequent breaks.

Adult↗

PubMed1995

Use of visual perception in estimating static postural stresses: magnitudes and sources of errors.

Very little is known about the magnitudes and sources of errors associated with the visual estimation of postural classification displayed on TV screens. This study was conducted to address this issue. Sixty-three subjects participated in the experiments. The findings indicate that: (1) subjects found it difficult to evaluate upper extremity postures (particularly the elbow and the wrist), while the postures around the lower back were the easiest to evaluate; (2) the lower extremity positions affected the ability of the subjects to accurately classify postures around the wrist, elbow, shoulder, neck, and lower back, with the estimates being > 70% for sitting and > 60% for standing (except for the elbow); and (3) in general, flexion and extension are easier to evaluate than neutral and non-neutral postures.

Adult↗

PubMed1994

On the investigation of the neurophysiological correlates of knowledge worker mental fatigue using the EEG signal.

Technological trends and advances in automation have underscored the importance of task performance of certain jobs requiring mental functions such as information processing and decision analyses. Most experts agree that such work environments produce increased mental activities, with profound implications for mental fatigue and stress. Consequently, productivity measurement and improvement for white collar or 'knowledge worker' occupations remains a major challenge and concern. This investigation defines an experimental approach that examines the neurophysiological correlates of white collar worker mental fatigue using the EEG signal. A 6 h laboratory experiment was conducted to simulate work output. The methods of assessing fatigue employed were mental tests and physiological measurements. The experiment involved reading of standardized texts, finding solutions to arithmetic-logical problems and a combination of both task types. Two primary performance measures were obtained, work output and brain waves. Fast Fourier transform and correlation analyses are used to quantify the relationship between certain brain waves and mental fatigue. This research is a major step towards the development of a model that explores the relationship between mental fatigue and factors associated with output performance, optimal recuperation periods and related variables. Such a model would be useful in human reliability prediction based on task parameters and worker profiles.

Journal Article↗

PubMed1993

Ergonomic risk assessment: preliminary guidelines for analysis of repetition, force and posture.

High repetition, excessive forces and awkward postures are a major cause of musculoskeletal disorders in industry. Thus, the main objective of this paper is to develop, based on the published literature, preliminary ergonomic guidelines for repetition, force, and posture task analysis. A method is also proposed which can be used to compute the interactive effects of repetition, force and posture.

Biomechanical Phenomena↗

PubMed1992

A multi-level incentive model for service organizations.

Incentive programmes for production employees have been used for many years. However, more recently, there has been an increasing desire to use incentive programmes in service applications, particularly with the advent of electronic performance monitoring. This paper summarizes the methodology for developing a model that incorporates the parameters of quality (customer and supervisor evaluations), quantity of production, sales and individual goals. The model was used to compute incentive bonus payments for customer service employees who performed above standard. Employees were motivated by the incentive bonus, and thus productivity was increased. The model could be applied to any service organization. The model was developed to assist a customer service department where performance standards, quality measures or customer feedback were not firmly established. It measured objectively employee performance and rewarded the employee with individually calculated incentive bonuses through an electronically monitored system. The internal working of the model is a combination of the above parameters. Customized software was used to collect and tabulate customer feedback regarding a recent inquiry to the customer service department. This made up the first part of the quality measure for the department. The second part of the quality parameter was a regular evaluation by the supervisor. The quantity of production was measured by the number of inquiries handled per unit time. Sales were also calculated on a per-unit-time basis. The individual goals were the result of regular employee-supervisor meetings where past and future employee performance was discussed and mutually agreed upon. The five model parameters of quality (customer and supervisor), quantity, sales and individual goals are combined through the use of a linear equation. It was found that this form of employee evaluation worked very well in an electronic monitoring environment and was accepted by the participating work group. Overall, monthly productivity gains exceeded 15%.

Journal Article↗

PubMed1992

A review and reappraisal of electronic performance monitoring, performance standards and stress allowances.

There is a growing trend toward electronic performance monitoring (EPM) to track the performance of workers engaged in computer-based tasks. Despite the possible productivity advantages of this approach to work management, the use of EPM may produce stress through work overload, negative computer feedback, loss of incentive pay and threat of job loss. These stress effects are most likely to occur among workers who have difficulty meeting work standards (eg, forms processed per hour) enforced through EPM. A stress allowance is proposed as a new category of work allowance for adjusting EPM work standards so as to minimize imbalances between task demands and the worker's resources to adapt.

Journal Article↗