Productivity drift in extended learning curves

The pattern of changes in the Extended Learning Curves representing the performance of 114 assembly workers in an electronics firm is examined in terms of changes in productivity drift over long periods of time. It is shown that 2 types of discontinuities can occur. The first consists of a temporary levelling off in productivity followed by a recovery to new higher levels of productivity; the second has a sustained period of negative productivity drift. A number of work facets are statistically tested as possible causes of these patterns of productivity drift, but, the only significant relationship (at P ≤ 0.05 level) is with length of service in job. Some evidence is presented to show that conventional work measurement methods are not effective in terms of assessing the true work output of experienced workers since such workers are able to beat the system by claiming those allowances which are most difficult to cross-check.     

A production engineering approach to robot selection

The successful introduction of robots into an industrial enterprise means real commitment, engineering support, and detailed involvement in the planning of an integrated manufacturing system. In particular, the production engineer is clearly seen in this context to be the system designer. He must therefore be in a position to specify the performance of all man and machine components within the system such that productivity is maximised. Robot types are reviewed, and analogies between man and machine are used to introduce the RTM concept. Finally, a simple method is given for estimating robot throughput times from elementary velocity profiles. The fall-off in throughput due to the effect of many small robot movements is emphasised.     

Ratings checklist for warnings: a prototype tool to aid experts in the adequacy evaluation of proposed or existing warnings

In the field of forensic human factors, experts are often called upon to assess and evaluate the adequacy of new or existing products' warnings or warnings systems. The usual goal of this evaluation is to arrive at a simple binary decision regarding the warning in question (i.e., does it "pass/fail", or is it "adequate/inadequate"). However, such a warning assessment process may in fact be quite complex and multidimensional in its execution. The existing warnings research literature has identified a fairly large number of warnings features or factors likely to have an impact on a given warning's effectiveness or adequacy. The tool addressed in this article is intended for use by a warnings expert (as opposed to one less knowledgeable and informed about complex warnings issues), and can serve as a reminder checklist to help ensure that the expert has taken into consideration the most relevant features or factors during such a warnings adequacy assessment.     

La Identidad y Caracter Nacionales en Mexico—La Frontera de Tamaulipas—

Resumen

En este artículo se analizan los datos de cuatro ciudades fronterizas de México. Estas son evaluaciones sobre el carácter e identidad nacional, inferidas a partir del sentido de pertenencia y participación de los ciudadanos en las instituciones más importantes de su Estado. Los resultados muestran que los habitantes de las ciudades fronterizas tienen un sentimiento de pertenencia muy reducido y un aún menor sentimiento de participación en las instituciones.     

Ride-on lawnmowers warnings: slope measurements and safety-by-separation

Various single-rider open vehicles, such as lawnmowers, are susceptible to overturning on slopes that are too steep for them. Warnings have included separation from the vehicles and avoiding slopes that are too steep. A recommended maximum slope is commonly 15 degrees. However, many individuals cannot evaluate slopes just by sight. Some mower manufacturers have warned about too steep slopes and have provided slope gauges for users to determine the slopes in natural settings. This article evaluated the usefulness of such gauges for users who might be expected to need to evaluate slopes and the efficacy of a separation procedure for avoiding injuries. It was concluded that neither of these were likely to be successful and suggestions are made for alternative approaches.