| 2. |
- Kazmierczak, Karolina, et al.
(författare)
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Observer reliability of industrial activity analysis based on video recordings
- 2006
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 36:3, s. 275-282
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to assess the agreement between observers analyzing activity patterns during truck engine assembly work based on video recordings. Two observers observed the recordings of nine workers, on the average 2.2 h long, assigning activities to four activity categories. For each activity category data were obtained on the mean duration of uninterrupted sequences of activities and their relative time proportion in the job. This data was analyzed with 2-way crossed ANOVA algorithms to derive the components of variance attributed to disagreement between observers, to differences between filmed subjects, and to residual "unexplained" variance. The latter was interpreted as an estimate of within-observer variability and possible interactions between subject and observer. While the observers disagreed about the overall time proportions for the four activity categories by no more than 3.7% of time, their second-to-second classification disagreed for 13% of the total analysis time. The between-observer variance was small as compared to within-observer variance and the variance between Subjects performing the same job. Simulations based oil the variance components showed that a group mean of the proportion of direct work could be determined with a standard deviation within 5% of the mean by having two observers analyzing one 2-h video recording once, each. Relevance to industry The results of this study may support decision making when designing a reliable video-based analysis of industrial work. Thus, the study helps production engineers, ergonomics practitioners and researchers allocate resources between data collection and data analysis, based on their preferences for precision and power of a particular study. (c) 2006 Elsevier B.V. All rights reserved.
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| 3. |
- Neumann, Patrick, et al.
(författare)
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A case study evaluating the ergonomic and productivity impacts of partial automation strategies in the electronics industry
- 2002
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 40:16, s. 4059-4075
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Tidskriftsartikel (refereegranskat)abstract
- A case study is presented that evaluates the impact of partial automation strategies on productivity and ergonomics. A company partly automated its assembly and transportation functions while moving from a parallel-batch to a serial line-based production system. Data obtained from company records and key informants were combined with detailed video analysis, biomechanical modelling data and field observations of the system. The new line system was observed to have 51% higher production volumes with 21% less per product labour input and lower work-in-process levels than the old batch-cart system. Partial automation of assembly operations was seen to reduce the total repetitive assembly work at the system level by 34%. Automation of transportation reduced transport labour by 63%. The strategic decision to implement line-transportation was found to increase movement repetitiveness for operators at manual assembly stations, even though workstations were constructed with consideration to ergonomics. Average shoulder elevation at these stations increased 30% and average shoulder moment increased 14%. It is concluded that strategic decisions made by designers and managers early in the production system design phase have considerable impact on ergonomic conditions in the resulting system. Automation of transport and assembly both lead to increased productivity, but only elements related to the automatic line system also increased mechanical loads on operators and hence increased the risk for work-related disorders. Suggestions for integrating the consideration of ergonomics into production system design are made.
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