Movement time when circumventing obstacles in a 3-D workspace

We have developed an appropriate Computational Fluid Dynamics (CFD) model for assessing the exposure to risk of tunnel users during their evacuation process in the event of fire. The effects on escaping users, which can be caused by fire from different types of vehicles located in various longitudinal positions within a one-way tunnel with natural ventilation only and length less than 1 km are shown. Simulated fires, in terms of maximum Heat Release Rate (HRR) are: 8, 30, 50, and 100 MW for two cars, a bus, and two types of Heavy Goods Vehicles (HGVs), respectively. With reference to environmental conditions (i.e., temperatures, radiant heat fluxes, visibility distances, and CO and CO2 concentrations) along the evacuation path, the results prove that these are always within the limits acceptable for user safety. The exposure to toxic gases and heat also confirms that the tunnel users can safely evacuate. The evacuation time was found to be higher when fire was related to the bus, which is due to a major pre-movement time required for leaving the vehicle. The findings show that mechanical ventilation is not necessary in the case of the tunnel investigated. It is to be emphasized that our modeling might represent a reference in investigating the effects of natural ventilation in tunnels.

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Effect of post-stroke spasticity on voluntary movement of the upper limb

Journal of NeuroEngineering and Rehabilitation ◽

10.1186/s12984-021-00876-6 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Hadar Lackritz ◽

Yisrael Parmet ◽

Silvi Frenkel-Toledo ◽

Melanie C. Baniña ◽

Nachum Soroker ◽

...

Keyword(s):

Upper Limb ◽

Target Location ◽

Distance Measure ◽

Movement Time ◽

Motor Impairment ◽

Reach To Grasp ◽

Motion Patterns ◽

Post Stroke ◽

The Impact ◽

Elbow Motion

Abstract Background Hemiparesis following stroke is often accompanied by spasticity. Spasticity is one factor among the multiple components of the upper motor neuron syndrome that contributes to movement impairment. However, the specific contribution of spasticity is difficult to isolate and quantify. We propose a new method of quantification and evaluation of the impact of spasticity on the quality of movement following stroke. Methods Spasticity was assessed using the Tonic Stretch Reflex Threshold (TSRT). TSRT was analyzed in relation to stochastic models of motion to quantify the deviation of the hemiparetic upper limb motion from the normal motion patterns during a reaching task. Specifically, we assessed the impact of spasticity in the elbow flexors on reaching motion patterns using two distinct measures of the ‘distance’ between pathological and normal movement, (a) the bidirectional Kullback–Liebler divergence (BKLD) and (b) Hellinger’s distance (HD). These measures differ in their sensitivity to different confounding variables. Motor impairment was assessed clinically by the Fugl-Meyer assessment scale for the upper extremity (FMA-UE). Forty-two first-event stroke patients in the subacute phase and 13 healthy controls of similar age participated in the study. Elbow motion was analyzed in the context of repeated reach-to-grasp movements towards four differently located targets. Log-BKLD and HD along with movement time, final elbow extension angle, mean elbow velocity, peak elbow velocity, and the number of velocity peaks of the elbow motion were computed. Results Upper limb kinematics in patients with lower FMA-UE scores (greater impairment) showed greater deviation from normality when the distance between impaired and normal elbow motion was analyzed either with the BKLD or HD measures. The severity of spasticity, reflected by the TSRT, was related to the distance between impaired and normal elbow motion analyzed with either distance measure. Mean elbow velocity differed between targets, however HD was not sensitive to target location. This may point at effects of spasticity on motion quality that go beyond effects on velocity. Conclusions The two methods for analyzing pathological movement post-stroke provide new options for studying the relationship between spasticity and movement quality under different spatiotemporal constraints.

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Relationship of Reaction Time and Movement Time in a Gross Motor Skill

Perceptual and Motor Skills ◽

10.2466/pms.1973.36.2.453 ◽

1973 ◽

Vol 36 (2) ◽

pp. 453-454 ◽

Cited By ~ 6

Author(s):

Richard Groves

Keyword(s):

Reaction Time ◽

Motor Skill ◽

Movement Time ◽

Gross Motor ◽

Moment Coefficient ◽

Relationship Of ◽

Gross Motor Skill

The purpose of the study was to investigate the independence of reaction time (RT) and movement time (MT) in a gross motor skill, the racing start in swimming. RT and MT were quantified for each S by counting frames of film for five trials. The Pearson product-moment coefficient of –.231 ( p > .05) between means indicated that RT and MT were independent factors.

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Experimental Evaluations of a Model of Mental Workload

Proceedings of the Human Factors Society Annual Meeting ◽

10.1177/154193128903301814 ◽

1989 ◽

Vol 33 (18) ◽

pp. 1233-1237 ◽

Cited By ~ 5

Author(s):

P. A. Hancock ◽

M. H. Chignell ◽

M. Vercruyssen ◽

M. Denhoff

Keyword(s):

Path Length ◽

Mental Workload ◽

Movement Time ◽

A Priori ◽

Independent Effect ◽

Subjective Perception ◽

Performance Task ◽

Related Factors ◽

Task Goal ◽

Systematic Effects

The present experiments were designed to test predictions from a model of mental workload. The model predicts non-linear increases in mental workload as perceived distance from a task goal grows and effective time for action is reduced. Diminution of mental workload is achieved by application of effort which brings the task goal into the region of acceptable time/distance constraints for successful resolution. Two experiments are reported which tested these assertions using the timepools performance task. Timepools is unique as a performance task in that it generates a spatial representation of a shrinking temporal target. The independent effects of path length, i.e., the number of sequential targets to be acquired, and shrink rate, i.e., the collapse time during which the circle is halved in area, may be assessed using performance variables such as reaction time (RT), movement time (MT), error rate (E), and the subjective perception of workload. Data from Experiment 1, indicate systematic effects for task related factors across performance and workload measures, although such a pattern was not isomorphically mapped to the a priori assumed difficulty of the task. In Experiment 2, shrink rate and path length had independent effect on RT and MT respectively, which were reflected in components of the individual workload scales. The ramifications with respect to the model are elaborated.

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Quantitative Models of Motor Responses Subject to Longitudinal, Lateral, and Preview Constraints

Human Factors The Journal of the Human Factors and Ergonomics Society ◽

10.1177/001872087802000105 ◽

1978 ◽

Vol 20 (1) ◽

pp. 35-39 ◽

Cited By ~ 6

Author(s):

Tarald O. Kvålseth

Keyword(s):

Experimental Data ◽

Motor Control ◽

Linear Models ◽

Movement Time ◽

Arm Movements ◽

Second Order ◽

Motor Responses ◽

First Order ◽

Different Types ◽

Index Of Difficulty

First- and second-order linear models of mean movement time for serial arm movements aimed at a target and subject to preview constraints and lateral constraints were formulated as extensions of the so-called Fitts's law of motor control. These models were validated on the basis of experimental data from five subjects and found to explain from 80% to 85% of the variation in movement time in the case of the first-order models and from 93% to 95% of such variation for the second-order models. Fitts's index of difficulty (ID) was generally found to contribute more to the movement time than did either the preview ID or the lateral ID defined. Of the different types of errors, target overshoots occurred far more frequently than undershoots.

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