Virtual trajectory and stiffness ellipse during multijoint arm movement predicted by neural inverse models

1993 ◽  
Vol 69 (5-6) ◽  
pp. 353-362 ◽  
Author(s):  
Masazumi Katayama ◽  
Mitsuo Kawato
Keyword(s):  
Arm Movement ◽  
Inverse Models ◽  
Virtual Trajectory

Optimization of Stiffness and Damping in Modeling of Voluntary Elbow Flexions

2011 ◽  
Author(s):  
Kai Chen ◽  
Richard Foulds
Keyword(s):  
Arm Movement ◽  
Random Order ◽  
Influential Factors ◽  
Emg Activity ◽  
Control Parameters ◽  
Skeletal System ◽  
Time Duration ◽  
Control Signals ◽  
Stiffness And Damping ◽  
Virtual Trajectory

A subsequent study of obstructed voluntary arm movement extended the relative damping concept, and incorporated the influential factors of the mechanical behavior of the neural, muscular and skeletal system in the control and coordination of arm posture and movement. A significant problem of the study is how this information should be used to modify control signals to achieve desired performance. This study used an Equilibrium Point Hypothesis (EPH) model to examine changes of controlling signals for arm movements in the context of adding perturbation/load in the form of forces/torques. The mechanical properties and reflex actions of muscles of the elbow joint were examined. Brief unexpected torque/force pulses of identical magnitude and time duration were introduced at different stages of the movement in a random order by a pre-programmed 3 degree of freedom (DOF) robotic arm (MOOG FCS HapticMaster). Key to this research is the optimization of B and K for each subject based on their HM only experimental data. The results shown in each of sections confirm that those parameters. Along with an EMG determined VT can be used successfully to model the perturbed trials. The results also show that the subjects may maintain the same control parameters (virtual trajectory, stiffness and damping) regardless of added perturbations that cause substantial changes in EMG activity and kinematics.

Curve Estimation Modeling for Predictions of the Novel Coronavirus (Covid-19) Epidemic in Nigeria

2020 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Christian Ebere Enyoh ◽  
Andrew Wirnkor Verla ◽  
Chidi Edbert Duru ◽  
Emmanuel Chinedu Enyoh ◽  
Budi Setiawan
Keyword(s):  
State Governments ◽  
The Novel ◽  
Curve Estimation ◽  
Exponential Models ◽  
Inverse Models ◽  
Forward Prediction ◽  
S Curve ◽  
Novel Coronavirus ◽  
Best Fit ◽  
Official Data

Based on the official Nigeria Centre for Disease Control (NCDC) data, the current research paper modeled the confirmed cases of the novel coronavirus disease 2019 (COVID-19) in Nigeria. Ten different curve regression models including linear, logarithmic, inverse, quadratic, cubic, compound, power, S-curve, growth, and exponential were used to fit the obtained official data. The cubic (R2 = 0.999) model gave the best fit for the entire country. However, the growth and exponential had the lowest standard error of estimate (0.958) and thus may best be used. The equations for these models were e0.78897+0.0944x and 2.2011e0.0944x respectively. In terms of confirmed cases in individual State, quadratic, cubic, compound, growth, power and exponential models generally best describe the official data for many states except for the state of Kogi which is best fitted with S-curve and inverse models.  The error between the model and the official data curve is quite small especially for compound, power, growth and exponential models. The computed models will help to realized forward prediction and backward inference of the epidemic situation in Nigeria, and the relevant analysis help Federal and State governments to make vital decisions on how to manage the lockdown in the country.

scholarly journals Effects of Attentional Focus on Motor Performance and Physiology in a Slow-Motion Violin Bow-Control Task: Evidence for the Constrained Action Hypothesis in Bowed String Technique

2021 ◽  
pp. 002242942110347
Author(s):  
Emma Allingham ◽  
Clemens Wöllner
Keyword(s):  
Music Education ◽  
Motor Performance ◽  
Body Movement ◽  
Music Performance ◽  
Arm Movement ◽  
Slow Motion ◽  
Attentional Focus ◽  
Electromyographic Activity ◽  
Constrained Action Hypothesis ◽  
Conscious Thinking

The constrained action hypothesis states that focusing attention on action outcomes rather than body movement improves motor performance. Dexterity of motor control is key to successful music performance, making this a highly relevant topic to music education. We investigated effects of focus of attention (FOA) on motor skill performance and EMG muscle activity in a violin bowing task among experienced and novice upper strings players. Following a pedagogically informed exercise, participants attempted to produce single oscillations of the string at a time under three FOA: internal (on arm movement), external (on sound produced), and somatic (on string resistance). Experienced players’ number of bow slips was significantly reduced under somatic focus relative to internal, although number of successful oscillations was not affected. Triceps electromyographic activity was also significantly lower in somatic compared to internal foci for both expertise groups, consistent with physiological understandings of FOA effects. Participants’ reported thoughts during the experiment provided insight into whether aspects of constrained action may be evident in performers’ conscious thinking. These results provide novel support for the constrained action hypothesis in violin bow control, suggesting a somatic FOA as a promising performance-enhancing strategy for bowed string technique.

Perceptual-Motor Attributes of Mental Retardates: A Factor Analytic Study

1971 ◽  
Vol 33 (3) ◽  
pp. 927-934 ◽  
Author(s):  
Renate L. Neeman
Keyword(s):  
Survey Methodology ◽  
Arm Movement ◽  
Mentally Retarded ◽  
Total Sample ◽  
Developmental Factor ◽  
Similar Factor ◽  
Mentally Retarded Children ◽  
Item Scores ◽  
Definition Of ◽  
Factor C

19 items of the Purdue Perceptual-motor Survey were administered to 99 mentally retarded children and young adults of mean IQ 52.3. Factor analyses of the item scores of the total sample, and of a subgroup of 66 non-mongoloid Ss, led to the definition of 7 factors: A, postural dimensionality; B, shoulder-arm movement factor; C, laterality; D, ocular control; E, intelligence; F, developmental factor; and G, possibly cultural sex bias factor. Similar factor structures emerged for the total sample, and for the non-mongoloid subgroup, with the exception of Factor E, intelligence. The results generally agree with previous correlational analyses of comparable samples and tend to support the construct validity of the Purdue Perceptual-motor Survey methodology as applied to the mentally retarded.

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