A Dynamic Speed vs. Accuracy Trade-Off (DSAT) Paradigm for Measuring and Training Grip Force Control for Stroke Population

2009 ◽  
Author(s):  
Nam H. Kim ◽  
Michael Wininger ◽  
Gail Forrest ◽  
Thomas Edwards ◽  
William Craelius
Keyword(s):  
Grip Force ◽  
Motor Behavior ◽  
Movement Time ◽  
Dynamic Performance ◽  
Fundamental Principle ◽  
Difficulty Level ◽  
Trade Off ◽  
Stroke Population ◽  
Speed Accuracy ◽  
And Training

A fundamental principle of human motor behavior states that the accuracy of targeted movements relates reciprocally to their speed. This is quantified by Fitts’ Law, wherein movement time (MT) and index of difficulty (ID), the log2 ratio of target distance (A) to target height (H) has logarithmic linear relationship; MT = a+b·log2(2A/H) = a+b·ID. The slope, b (seconds/bits), measures targeting performance as the time spent at each difficulty level, expressed as bits of information to be processed by the neuromotor system [1, 2]. Fitts’ paradigm is a common measure of the kinematic performance of the upper limb, but has not been applied to its dynamic performance. Herein, we developed a dynamic speed-accuracy trade-off (DSAT) test of grip force modulation, which can be used both for assessment and training.

A Curvilinear Effect of Mental Workload on Mental Effort and Behavioral Adaptability: An Approach With the Pre-Ejection Period

2019 ◽  
Vol 62 (6) ◽  
pp. 928-939 ◽  
Author(s):  
Charlotte Mallat ◽  
Julien Cegarra ◽  
Christophe Calmettes ◽  
Rémi L. Capa
Keyword(s):  
Traffic Control ◽  
Task Difficulty ◽  
Mental Workload ◽  
Movement Time ◽  
Intermediate Level ◽  
Behavioral Strategies ◽  
Trade Off ◽  
Linear Effect ◽  
Speed Accuracy ◽  
Curvilinear Effect

Objective We tested Hancock and Szalma’s mental workload model, which has never been experimentally validated at a global level with the measure of the pre-ejection period (PEP), an index of beta-adrenergic sympathetic impact. Background Operators adapt to mental workload. When mental workload level increases, behavioral and physiological adaptability intensifies to reduce the decline in performance. However, if the mental workload exceeds an intermediate level, behavioral and physiological adaptability will decrease to protect individuals from excessive perturbations. This decrease is associated with a change in behavioral strategies and disengagement. Method The experimental task was a modified Fitts’ task used in Hancock and Caird. Five levels of task difficulty were computed. Behavioral and physiological adaptability was indexed by the performance with speed–accuracy trade-off and PEP reactivity. Results A curvilinear effect of task difficulty on PEP reactivity was significant, with high reactivity at the intermediate level but low reactivity at other levels. We observed a linear effect of task difficulty on error rate and a curvilinear effect on movement time. A decline in performance was noted up to the intermediate level, with a speed–accuracy trade-off above this level showing a faster movement time. Conclusion We observed for the first time behavioral and physiological adaptability as a function of mental workload. Application The results have important implications for the modeling of mental workload, particularly in the context of the performance-sensitive domain (car driving and air traffic control). They can help guide the design of human–computer interaction to maximize adaptive behavior, that is, the “comfort zone.”

Conditions for a Linear Speed-Accuracy Trade-Off in Aimed Movements

1983 ◽  
Vol 35 (2) ◽  
pp. 279-296 ◽  
Author(s):  
Charles E. Wright ◽  
David E. Meyer
Keyword(s):  
Standard Deviation ◽  
Movement Time ◽  
Target Point ◽  
Home Position ◽  
Trade Off ◽  
Linear Speed ◽  
Temporal Precision ◽  
Fitts Law ◽  
Per Se ◽  
Speed Accuracy

A linear speed-accuracy trade-off has been found for rapid, precisely timed movements from a home position toward a target point. In this trade-off, We = K1 + K2(D/T), where D is the distance between the home position and the target, T is a pre-specified movement time, and We is the standard deviation of the distances actually moved. This result differs from Fitts' law, the commonly observed logarithmic trade-off in aimed movements. A new experiment with wrist rotations was performed to determine what conditions induce the linear trade-off rather than Fitts' law. Three types of condition are considered: movement brevity, feedback deprivation, and temporal precision. The experiment yielded a linear trade-off for precisely timed movements even when their durations significantly exceeded an amount of time (200 ms) sufficient to process visual feedback. This result suggests that the linearity does not depend on movement brevity and/or feedback deprivation per se. Instead it supports a temporal-precision hypothesis that the linear trade-off occurs when aimed movements must have precisely specified durations.

Speed and Accuracy of Eye-Gaze Pointing

1997 ◽  
Vol 85 (2) ◽  
pp. 705-718 ◽  
Author(s):  
Chia-Fen Chi ◽  
Chia-Liang Lin
Keyword(s):  
Eye Movement ◽  
Movement Time ◽  
Eye Gaze ◽  
Target Size ◽  
Trade Off ◽  
Starting Position ◽  
Fitts Law ◽  
Saccadic Movement ◽  
Speed Accuracy ◽  
Speed And Accuracy

The current experiment examined the speed-accuracy trade-off of saccadic movement between two targets. Ten subjects looked alternately at two targets as fast and as accurately as possible for 2 min. under different conditions of target size, distance between targets, and direction of eye movement. Saccadic movement of the left eye was tracked and recorded with an infrared eye monitoring device to compute the starting position, ending position, and duration of each saccadic movement. Eye-movement time was significantly related to target size and distance between targets, but the speed-accuracy trade-off was significantly different from that predicted by Fitts' Law. Reaction time was not significantly changed by the direction of eye movement.

scholarly journals Consistent Individual Tendencies in Motor Speed-Accuracy Trade-Off

2021 ◽  
Author(s):  
Matheus Pacheco ◽  
Charley W. Lafe ◽  
Che-Hsiu Chen ◽  
Tsung-Yu Hsieh
Keyword(s):  
Motor Control ◽  
Movement Time ◽  
Motor Speed ◽  
Bayesian Analyses ◽  
Trade Off ◽  
Practice Condition ◽  
Speed Accuracy ◽  
Mean Variance ◽  
Interpretation Of Results

The literature of Speed-Accuracy Trade-Off (SAT) in motor control has evidenced individuality in the preference to trade different aspects (mean, variance) of spatial and temporal errors. Nonetheless, to the best of our knowledge, how robust this preference is has not been properly tested. Thirty participants performed nine conditions with different time and spatial criteria over two days (scanning). In-between these scanning conditions, individuals performed a practice condition that required modifications of the individuals’ preferences in SAT. Through Bayesian analyses, we found that, despite individuals demonstrating changes during practice, decreasing movement time, they did not modify how they performed the scanning conditions. This is evidence for a robust SAT individual tendency. We discuss how such individuality could modify how individuals perform within/between SAT criteria, and what this means for interpretation of results.

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

Robust Two-degree-of-freedom Control Based on H∞ Method for PMSM Drive System

2020 ◽  
Vol 13 (4) ◽  
pp. 496-506
Author(s):  
Qixin Zhu ◽  
Lei Xiong ◽  
Hongli Liu ◽  
Yonghong Zhu ◽  
Guoping Zhang
Keyword(s):  
Control System ◽  
Control Theory ◽  
Position Control ◽  
Dynamic Performance ◽  
Servo System ◽  
Degree Of Freedom ◽  
Trade Off ◽  
Standard Design ◽  
Position Controller ◽  
Two Degree Of Freedom

Background: The conventional method using one-degree-of-freedom (1DOF) controller for Permanent Magnet Synchronous Motor (PMSM) servo system has the trade-off problem between the dynamic performance and the robustness. Methods: In this paper, by using H∞ control theory, a novel robust two-degree-of-freedom (2DOF) controller has been proposed to improve the position control performance of PMSM servo system. Using robust control theory and 2DOF control theory, a H∞ robust position controller has been designed and discussed in detail. Results: The trade-off problem between the dynamic performance and robustness which exists in one-degree-of-freedom (1DOF) control can be dealt with by the application of 2DOF control theory. Then, through H∞ control theory, the design of robust position controller can be translated to H∞ robust standard design problem. Moreover, the control system with robust controller has been proved to be stable. Conclusion: Further simulation results demonstrate that compared with the conventional PID control, the designed control system has better robustness and attenuation to the disturbance of load impact.

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