title: Repetitive work and the monitoring methods of operators in various production situations during day- and night-shifts.
abstract: The purpose of this research is to determine to what extent operators carrying out repetitive machine-monitoring and feeding work can adapt their monitoring methods to the different production situations that they encounter, but also to the internal variations in their bodies during a 24-hour period. The activities of four log debarker operators were studied in a sawmill operating during the day and during the night (7 a.m. to 5 p.m. and 7 p.m. to 5 a.m.). The glance axis direction was observed in three more or less conflictual production situations (total 16 shifts). The technical and time constraints leave the operators very little margin of manoeuvre, and in normal production situations very little difference is found in the monitoring methods within one shift and between the two shifts. However, changes are observed between the day and night shifts if the monitoring methods are compared during production situations that the operators find more difficult to manage. These results are not consistent with a decrease in activities. In fact, during the night, these operators use their capabilities to an even greater extent to monitor a more conflictual situation more thoroughly. This result can be explained by the changes in people's memory during the night, and by the lower threshold at which an operator decides that a situation is critical at night as compared to the daytime.
authors.affiliation: Department of Industrial Relations, Université Laval, Québec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Montreuil
mesh_terms: D002940:Circadian Rhythm; D006804:Ergonomics; D006801:Humans; D008297:Male; D011590:Psychology, Industrial; D013647:Task Performance and Analysis