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Similaire à Nps Hsv Motion Presentation
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Nps Hsv Motion Presentation
- 1. High Speed Vessel (HSV) Motion Effects on Crew Performance A Preliminary Analysis of Motion Induced Effects (MIE) By M.E. McCauley, Ph.D., Naval Postgraduate School Lt P. Matsagas, M.Sc., Hellenic Navy Network Centric Defence Conference 2005 “A Challenge for the Hellenic Armed Forces in the 21 st Century"
- 5. Effects of motion on crew performance The grayed box represents the parameters analyzed in the present work.
- 8. Pre-test survey Motion Induced Interruptions (cont) Relative frequency of reported MII severity per sea state condition per smoothest 5-minute interval Relative frequency of reported MII severity per sea state condition per roughest 5-minute interval
- 9. Test data Motion Sickness Analysis Early stoppers: Test questionnaires mean values per local-time day (vertical bars correspond to MSAQ/ TMSI confidence intervals for the means at a=0.05)
- 10. Test data Motion Sickness Analysis Normal stoppers: Test questionnaires mean values per local-time day (vertical bars correspond to MSAQ/ TMSI confidence intervals for the means at a=0.05)
- 11. Test data Motion Sickness Analysis Comparison of MSAQ absolute values between Early and Normal Stoppers 2.66 “ Normal” (n=301) 0.016 3.10 “ Early” (n=73) SSS: Sleepiness 11 – 100 19.79 “ Normal” (n=311) < 0.001 11 – 69 35.78 “ Early” (n=75) MSAQ: Sopite Index 11.56 “ Normal” (n=311) 0.005 15.60 “ Early” (n=75) MSAQ: Peripheral Index 11.55 “ Normal” (n=311) 0.037 12.21 “ Early” (n=75) MSAQ: Central Index 12.88 “ Normal” (n=311) 0.004 18.89 “ Early” (n=75) MSAQ: Gastrointestinal Index 11 – 42 13.95 “ Normal” (n=311) < 0.001 11 – 56 20.41 “ Early” (n=75) MSAQ: Total Motion Sickness Index P-value (one-tailed) Range Mean values “ Stoppers” Parameter
- 12. Test data Analysis Combined “Early” and “Normal” stoppers. Test questionnaires mean values per local-time day (vertical bars correspond to MSAQ/ TMSI confidence intervals for the means at a=0.05)
- 13. Test data MII – MS – Ship motion Analysis Combined “Early” and “Normal” stoppers. Reported MIIRoughest, and MSAQ/ TMSI (local day mean values, vertical bars correspond to MIIs confidence intervals for the means at a=0.05)
Notes de l'éditeur
- As you can see on the slide, the emergent need for high speed is evident under Network Centric Operations concept. In simple terms “With fewer ships (reduced costs) we have to be everywhere”
- Present work deals with a “top-down” approach of a ship’s operability. Because, a model which relates basic human performance components to ship’s operability criteria (although a mid step has been made by Graham and Colwell (1990) to define representative naval tasks) , we measure and analyze some generic measures of performance. We approach the effects of ship’s motion on human performance according to the depicted diagram. In current work we deal with the effects of ship’s motion on crew’s performance through motion sickness, sopite syndrome and motion induced interruptions (MII). The metric to evaluate severity of motion sickness will be Motion Sickness Assessment Questionnaire (MSAQ) (Gianaros et al., 2001). Sopite syndrome is symptom related with the onset of motion sickness, which leads to increased levels of sleepiness, drowsiness and mental depression. In many cases sopite syndrome may be the only symptom of motion sickness We define an MII as an incidence of stopping the task that the subject is dealing with, due to ship’s motion effect. This definition includes a range of biodynamic interferences that are evident in moving platforms and the earlier definition did not take into account.
- In the pre-test surveys, twelve participants (63%) reported certain types of Motion Induced Interruptions (MII) as “common” on the ship, although all participating crew members reported the existence of MIIs. Four (21%) participants reported that retaining their posture does not become more difficult by time, whereas fifteen (79%) reported the opposite. Five participants (28%) reported that they have been injured due to MII on board HSV. The slide depicts the relative frequencies of recognized MIIs
- The relative frequency of reported MII severity per sea state condition and per 5-minute interval (smoothest and roughest) is depicted on the slide. There wasn’t any significant correlation between watch/ duty station and average number of reported MIIs. The average reported time needed to commence a task after a crew member has gone through an MII was 14.3 [sec] (median 10 [sec]), but shows large variability (minimum 2,5 [sec], maximum 37,5 [sec]).
- As it was expected, there was a large variation among participants in reported motion sickness and sopite syndrome during the test period (11th till 22nd May). In general, the reported motion sickness scores were low, which was normal because the crew was adapted to ship’s motion
- Although the range of percentage-wise analysis is almost identical (approximately 85% to 135%) between the two groups, there are significant differences in absolute values which are depicted in the following slide
- In all the aforementioned cases the significant differences were related to larger mean scores in “Early stoppers”. This result will be used later on.
- Next step in the percentage-wise analysis of the reported data, is to combine the “Early stoppers” and “Normal stoppers” into one population. The following figure depicts the time change of MSAQ/ TMSI and MSAQ/ SI averaged over local days.
- Analysis of MIIs data from Figure 8 (all data averaged over local-time days) show significant correlation between the reported MIIRoughest and the ship’s motion activity detected by the strapped actiwatch (one-way ANOVA, , p<0.001, a=0.05). Regression analysis revealed a significant slope coefficient of 3.3379 (p<0.001, confidence interval 4.62 – 2.05, a=0.05). Ship’s motion played a significant role on the crew’s psychological and physiological state. There was a deteriorating effect of MIIs on the crew’s mood (feeling annoyance/ irritation) (MIIRoughest: r=0.63, p=0.028, MIISmoothest: r=0.61, p=0.035), and subjectively rated physiological fatigue (MIIRoughest: r=0.70, p=0.011, MIISmoothest: r=0.70, p=0.011).
- The adaptation process becomes evident when data from the 11th and 12th may are omitted. Due to the irregular effect that ship’s motion pose on motion sickness, and sopite syndrome during the first two days underway, the correlation coefficients between the aforementioned parameters and ship’s motion activity is smaller than the corresponding correlation when the first two days are omitted MSAQ/TMSI and MSAQ/SI values during the 11th -12th May were found significantly larger than the corresponding ones during 13th -17th May (p=0.03 and p<0.01 respectively). The time periods chosen in the latter comparisons have include sea-trial periods. No adaptation effect was found in MIIs.
- Although, MII and MSI are simple cause-and-effect parameters which relate the ship’s motion and the human response, they do not take into account the effect of higher cognitive processes to human performance. The approach used in this work will be based on the following two step process (Crossland et al., 1994): a) from ship’s motion estimate symptomatology, and b) from symptomatology, estimate performance. In this case symptomatology describes the presence and severity of symptoms produced by ship’s motions. The symptoms which were detected onboard HSV and are related to human performance are the ones depicted on the slide: Sopite syndrome: The syndrome effect was more evident than symptoms of motion sickness, and the corresponding absolute reported values showed a wider range (ranging from 11.1 till 100.00). A 2-day adaptation period has been identified. Motion sickness: Absolute values of reported MSI were fairly low on HSV. This is attributed to the overall adaptation of the crew to the ship’s motion and the fact that during the transatlantic transit it is easy to choose ship’s courses so as to minimize motion effects (a method generally used when there aren’t any operational or missions constraints/ directives). A 2-day adaptation period has been identified. Nevertheless, crew’s comments about ship’s motion effects during sea-trials revealed the significant nauseogenic and biodynamic influence on the crew (inability to sleep, vomiting, etc). One interesting aspect of the aforementioned finding is that it is not depicted in the corresponding test questionnaires scores. One possible explanation is that the participating crew chose not to fill out the tests while they were under severe motion influence; instead they reported their prior experience as a comment.
- Motion Induced Interruptions: Biodynanic interference was significantly larger during sea-trials periods, were ship’s heading and speed couldn’t be chosen so as to minimize the effect on the structure and the personnel. We speculate that these periods give the real MII influence during theatre operations. The lack of adaptation in MIIs is concise with existing research (Colwell, 1989). Period of participation in the study: As already mentioned, the number of tests that the participants chose to fill out showed wide variability, ranging from five to forty nine. This result can be used in favor of performance analysis because it is known that the overall effect of the stressors onboard a ship result in mood change. The aforementioned findings give a possible explanation why some of the crew members chose to stop their participation in the present study before schedule. It’s obvious that all participants had to deal with their duties/ ship’s routine (primary task) and the study’s heavy test schedule (secondary task). The increased workload combined with raised levels of motion sickness, and drowsiness due to sopite syndrome, led the “early stoppers” (36% of the fourteen participants) to discontinue their effort towards their secondary task. Such deterioration in motivation, initiative, and willingness to perform is concise with earlier research