Catastrophe Models for Cognitive Workload and Fatigue

We reconceptualised several problems concerning the measurement of cognitive workload – fixed versus variable limits on channel capacity, work volume versus time pressure, adaptive strategies, resources demanded by tasks when performed simultaneously, and unclear distinctions between workload and fatigue effects – as two cusp catastrophe models: buckling stress resulting from acute workload, and fatigue resulting from extended engagement. Experimental participants completed a task that was intensive on non-verbal episodic memory and had an automatically speeded component. For buckling stress, the epoch of maximum (speeded) performance was the asymmetry parameter; however, anxiety did not contribute to bifurcation as expected. For fatigue, the bifurcation factor was the total work accomplished, and arithmetic, a compensatory ability, was the asymmetry parameter; R2 for the cusp models outperformed the linear comparison models in both cases. A research programme is outlined that revolves around the two models with different types of task and resource configurations

Design of Equipment Rack with TRIZ Method to Reduce Searching Time in Change Over Activity (Case Study : PT. Jans2en Indonesia)

Janssen is a manufacturing plant that works in furniture assembly. Component shortages often occurs, it will cause the increase of work in process (WIP) in assembly section. In previous studies, we analyze the root causes with FMEA and then it is resulted that router section is the constraint of the system. There are many non value added activities such as searching and transportation caused by a messy condition of work places and the devices that aren’t put in the right place. The impact is that the time allocated for every change over is higher than before. There are many components that are worked by the router section, so improvements are needed to minimize changes in over time. 5S method and the use of a new design of rack by TRIZ method are suggested for fixing the conditions of work environment. It is expected to eliminate non value added activities and changes in over time. Result shows that we can reduce non value activities in change over of regular components up to 41% and the elimination of this time is 41,6%. The non value activities in changeover of new items is 36,6% and this elimination of time is 53,3%. Key word : change over, kaizen, design, TRIZ metho

Ergonomic Evaluation on Chicken Feeder Tool at Egg-Laying Chicken Farm SME

This research aims to evaluate the egg-laying chicken feeder that was designed at egg-laying chicken farm small and medium enterprise (SME). The main reason of this tool design was due to the worker’s complain of feeling pain during the feeding process. Evaluation was performed based on Nordic Body Map questionnaire result, physiological workload, and NIOSH lifting equation calculation. The observed work ranged from the feed filling in the basket until all feeds were distributed. The results showed that the %CVL was in the range of 18%-30% and the energy consumption of workers was in the range of 1.24-3.00 Kcal/minute. Thus, physiologically, the work activities carried out by the feed workers were categorized as very light workload. Meanwhile, evaluation using Lifting Index (LI) methods in the process of feeding showed the LI value ranged from 0.9-1, therefore this activity is safe to perform manually. Based on the prototype evaluation on the feeding aid, the process of feeding activities was more effective 1.5 times faster than the old tools. In addition, with the use of this new tool, the feeding process was easier to adjust the dose each time

Aerospace Medicine and Biology: a Continuing Bibliography with Indexes (Supplement 328)

This bibliography lists 104 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during September, 1989. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

The use of heart rate indices and subjective questionnaires in the determination of fatigue in motor-manual tree felling and delimbing operations in New Zealand exotic plantation forests : a thesis presented in partial fulfilment of the requirements for the degree of Master of Business Studies in Ergonomics at Massey University

This study assessed the use of heart rate indices and subjective questionnaires in the determination of fatigue in motor-manual tree felling operations in New Zealand exotic plantation forests. The research design consisted of a causal study utilising an amalgamation of both observational and ex post facto data collection techniques employing a cross sectional case study approach within a field study research environment. Findings from the research indicate that motor-manual tree felling and delimbing are tasks not necessarily analogous with excessively high levels of fatigue, even though the physiological measures categorised motor-manual felling and delimbing as being moderate to heavy workload tasks. Chronic fatigue was avoided, and acute fatigue mitigated by the effective use of the fallers self-pacing mechanism, combined with both structured and spontaneous rest breaks analogous with the work method adopted by motor-manual fallers. Consequently, production was not negatively affected by the progression of the working day. Poor work postures commonly adopted by the fallers encourage the progressive development musculo-skeletal damage. Hazards encountered by the subjects followed national trends for felling and trimming. Significant decreases in thermal comfort and sensation ratings occurred, accompanied by an increase in the skin wettedness rating and higher thermal regulation ratings for the majority of the fallers. No discernible increase in mental fatigue could be identified during the study. The ambient thermal environment and work site terrain had minimal effect on the subjects performance levels or physiological and psycho-physiological loadings

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 324)

This bibliography lists 200 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during May, 1989. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Ergonomics of the Operative Field in Paediatric Minimal Access Surgery

Imperial Users onl

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 199

This bibliography lists 82 reports, articles, and other documents introduced into the NASA scientific and technical information system in October 1979