Occupational Ergonomics - Volume 6, issue 2

Authors: Landau, Kurt | Strasser, Helmut

Article Type: Editorial

DOI: 10.3233/OER-2006-6201

Citation: Occupational Ergonomics, vol. 6, no. 2, pp. 57-57, 2006

Authors: Goebel, Matthias | Zschernack, Swantje | Yoo, Jae-Woo

Article Type: Research Article

Abstract: Inspection tasks become more and more important for modern production and complex high reliability systems. A major particularity of inspection tasks is to be seen in the fact that the central work process cannot be observed externally. Although inspections tasks include physical activity, the inspection task itself is basically a perceptional and cognitive procedure. Due to the lack of accessibility of a 'work process' or an execution strategy it cannot be broken into separate work steps and cause-effect-relationships. Thus, common ergonomics intervention and design strategies as used for production and service tasks may not be applied similarly for inspections tasks. …Requiring to anticipate the attributes of a potential work design variant without having a complete analysis option at hand, explains why engineering and design of work systems remains mostly an expert task. A conceptual model is required to constitute the application of ergonomics knowledge for the design of inspection tasks by delivering insight into the mechanisms contributing or impairing inspection performance. Therefore a work system model is proposed which aims to integrate the most relevant ergonomics concepts in a consistent frame, based on the formal principles of system theory. The linear combination of different approaches shall allow to represent and to explain the complexity of system behavior. This model is extended by a compatible design approach explaining a general structure of design processes and its relationship to the work system model. On the base of the proposed conceptual approach, the particularities of inspections tasks are outlined. This shall support a systematic design of inspection tasks which lack an objective control both on the working level and on the design level. Show more

Keywords: Inspection task, cognitive behavior, complexity, work system modeling, design process, decision making

DOI: 10.3233/OER-2006-6202

Citation: Occupational Ergonomics, vol. 6, no. 2, pp. 59-73, 2006

Authors: Brombach, Johannes | Hütte, Thorsten | Strasser, Helmut

Article Type: Research Article

Abstract: In order to rate the ergonomic quality of lighting scenarios with respect to the use of directional and diffuse lighting in laboratory studies, Landolt rings (test signs) were carved into typical industrially manufactured surfaces via laser, representing three-dimensional "reliefs." Besides illumination with a luminance level of 750 lx (lighting scenario 1), which is recommended for inspection tasks according to a European standard, diffuse light (lighting scenario 2), directional light (lighting scenario 3), and lighting which was specifically chosen for each of the five surface types (lighting scenarios 4–8 were utilized. The general result of the analysis of the objective data …showed that three-dimensional reliefs on typical industrially manufactured surfaces are usually easier to recognize under directional light (lighting scenario 3) than under diffuse light (lighting scenario 2). At the same time, however, the test subjects indicated on the questionnaires that illumination with pure directional light was often perceived as uncomfortable. Illuminations which combined directional and diffuse light were usually a good compromise between the objective results and the subjective evaluations and can generally be recommended for mainly diffuse reflecting surfaces. Show more

Keywords: Laboratory studies, lighting conditions, directional and diffuse light, visual acuity, subjective ratings

DOI: 10.3233/OER-2006-6203

Citation: Occupational Ergonomics, vol. 6, no. 2, pp. 75-83, 2006

Authors: Schütte, Martin

Article Type: Research Article

Abstract: The aim of the present investigation was to prove in which way the decisions of quality inspectors are influenced by a change in the probability of faulty products, the kind and regularity of feedback. 72 participants took part in the experiment. The proportion of faulty objects was manipulated in three ways. The rate of a faulty object constantly amounted to 14% or increased from 11 to 17% or decreased from 17 to 11%. During task execution there was either no feedback or information about the number of missed faulty objects or about the number of missed faulty objects as well …as the number of false alarms. Feedback was given either constantly after inspection of 20 objects or after a varying number of objects which however amounted to 20 on average. The so-called c-index was calculated describing the response bias. The experimental results demonstrate that the decision behavior is changing in dependence on shifts of the number of faulty objects when feedback takes place at irregular intervals and when the number of missed faulty objects is given as feedback. The results are discussed with respect to possible work design measures adequate for the stabilization of the decision behavior. Show more

Keywords: Quality inspection, decision criterion, mode of feedback, regularity of feedback, changing fault rates

DOI: 10.3233/OER-2006-6204

Citation: Occupational Ergonomics, vol. 6, no. 2, pp. 85-93, 2006

Authors: Landau, Kurt | Peters, Helmut

Article Type: Research Article

Abstract: Investigations revealed poor ergonomic design, unsatisfactory logistics and quality problems at assembly and inspection workplaces in a large corporation supplying fenders to the automotive industry. A 138-item job design checklist was used to assess 59 reference workplaces. The design profiles highlighted weak points, especially as regards anthropometry and movement sequences. Ergonomically optimised assembly and inspection workplaces compatible with production flow were designed and introduced. Productivity improvement groups were created and action was taken to encourage good ergonomic behaviour. Job contents were enlarged.

Keywords: Inspection tasks, automotive industry, workplace design checklist

DOI: 10.3233/OER-2006-6205

Citation: Occupational Ergonomics, vol. 6, no. 2, pp. 95-105, 2006

Authors: Winter, Gabriele | Schaub, Karlheinz | Landau, Kurt

Article Type: Research Article

Abstract: Assembly work and inspection and testing tasks tend to be combined nowadays in the automotive industry as a way of achieving job enrichment. Workers inspect and test parts manufactured or assembled by them. This is in addition to routine quality assurance activities. As well as introducing new sensory demands into the jobs, this integration of assembly and inspection activities also brings with it significant additional motor components, which lead to musculo-skeletal strains. No empirical studies of the superimposed stresses involved in this type of job has been performed to date in the automotive industry. A ergonomically representative sample of work …at 22 work stations shows that, whilst most of the work is performed close to the body and involves a substantial proportion of standing positions and strenuous forced postures, only relatively low levels of forces have to be applied. In contrast, tasks requiring the use of testing tools have to be performed farther from the body and higher forces have to be applied. The findings reported from this study led to the design of a screening procedure for the predominantly physical stresses arising in assembly and inspection work in the automotive industry. Show more

Keywords: Assembly work, inspection tasks, checklists, risk assessment

DOI: 10.3233/OER-2006-6206

Citation: Occupational Ergonomics, vol. 6, no. 2, pp. 107-120, 2006