Journal articles on the topic 'Time and speed of one movement'
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1
Gottlieb, Gerald L., Daniel M. Corcos, and Gyan C. Agarwal. "Strategies for the control of voluntary movements with one mechanical degree of freedom." Behavioral and Brain Sciences 12, no. 2 (June 1989): 189–210. http://dx.doi.org/10.1017/s0140525x00048238.
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AbstractA theory is presented to explain how accurate, single-joint movements are controlled. The theory applies to movements across different distances, with different inertial loads, toward targets of different widths over a wide range of experimentally manipulated velocities. The theory is based on three propositions. (1) Movements are planned according to “strategies” of which there are at least two: a speed-insensitive (SI) and a speed-sensitive (SS) one. (2) These strategies can be equated with sets of rules for performing diverse movement tasks. The choice between SI and SS depends on whether movement speed and/or movement time (and hence appropriate muscle forces) must be constrained to meet task requirements. (3) The electromyogram can be interpreted as a low-pass filtered version of the controlling signal to the motoneuron pools. This controlling signal can be modelled as a rectangular excitation pulse in which modulation occurs in either pulse amplitude or pulse width. Movements to different distances and with loads are controlled by the SI strategy, which modulates pulse width. Movements in which speed must be explicitly regulated are controlled by the SS strategy, which modulates pulse amplitude. The distinction between the two movement strategies reconciles many apparent conflicts in the motor control literature.
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Joiner, Wilsaan M., Obafunso Ajayi, Gary C. Sing, and Maurice A. Smith. "Linear Hypergeneralization of Learned Dynamics Across Movement Speeds Reveals Anisotropic, Gain-Encoding Primitives for Motor Adaptation." Journal of Neurophysiology 105, no. 1 (January 2011): 45–59. http://dx.doi.org/10.1152/jn.00884.2009.
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The ability to generalize learned motor actions to new contexts is a key feature of the motor system. For example, the ability to ride a bicycle or swing a racket is often first developed at lower speeds and later applied to faster velocities. A number of previous studies have examined the generalization of motor adaptation across movement directions and found that the learned adaptation decays in a pattern consistent with the existence of motor primitives that display narrow Gaussian tuning. However, few studies have examined the generalization of motor adaptation across movement speeds. Following adaptation to linear velocity-dependent dynamics during point-to-point reaching arm movements at one speed, we tested the ability of subjects to transfer this adaptation to short-duration higher-speed movements aimed at the same target. We found near-perfect linear extrapolation of the trained adaptation with respect to both the magnitude and the time course of the velocity profiles associated with the high-speed movements: a 69% increase in movement speed corresponded to a 74% extrapolation of the trained adaptation. The close match between the increase in movement speed and the corresponding increase in adaptation beyond what was trained indicates linear hypergeneralization. Computational modeling shows that this pattern of linear hypergeneralization across movement speeds is not compatible with previous models of adaptation in which motor primitives display isotropic Gaussian tuning of motor output around their preferred velocities. Instead, we show that this generalization pattern indicates that the primitives involved in the adaptation to viscous dynamics display anisotropic tuning in velocity space and encode the gain between motor output and motion state rather than motor output itself.
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Flanders, M., and U. Herrmann. "Two components of muscle activation: scaling with the speed of arm movement." Journal of Neurophysiology 67, no. 4 (April 1, 1992): 931–43. http://dx.doi.org/10.1152/jn.1992.67.4.931.
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1. The temporal waveform of muscle activity was related to the speed of arm movement. Speed was expressed in terms of the duration of a fixed amplitude movement or the "movement time." 2. Human subjects moved their arms to targets in three-dimensional space. The right arm started at a standard initial position and moved directly to the target in a single stroke. The targets were placed in various directions in a vertical plane. The arm movements consisted of shoulder and elbow rotations. 3. Subjects were required to vary the speed of their movements. In most of the experiments, trials with different movement times were randomly ordered. One of the experiments also included randomly interspersed static trials, in which the subject held the arm still at the initial posture, the final posture, or halfway between the two extremes. 4. Electromyographic (EMG) activity was recorded from several superficial elbow and/or shoulder muscles. The time base of rectified EMG records was normalized for movement time such that records from movements with various speeds were compressed to align the ending times of the movements. 5. A principal component (PC) analysis revealed that the compressed EMG waveforms could be described by a summation of PC1 and PC2 waveforms; each individual EMG waveform was approximated by a weighted sum of these two components. 6. The PC1 weighting coefficients scaled down in a monotonic relationship with movement time such that the fastest movement corresponded to a large positive weighting coefficient and the slowest movement corresponded to a small positive weighting coefficient. The PC2 weighting coefficients exhibited a similar monotonic scaling, but the values ranged from positive to negative. Further analysis demonstrated that these two components can be mathematically transformed into a tonic waveform with a constant mathematically transformed into a tonic waveform with a constant weighting coefficient and a phasic waveform with positive weighting coefficients that scale down with movement time. 7. The amplitude scaling of EMG records cannot be described by a single component, but instead requires a summation of two separate components. The tonic component may correspond to the force element needed to counteract gravity, because the magnitude of this element does not scale with movement speed. The phasic component may correspond to the force element that scales quadratically to produce a linear increase in velocity.
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Lee, C.-S., J.-H. Lee, H. Pak, SW Park, and D.-W. Song. "Phantom array and stroboscopic effects of a time-modulated moving light source during saccadic eye movement." Lighting Research & Technology 50, no. 5 (February 20, 2017): 772–86. http://dx.doi.org/10.1177/1477153517693468.
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This paper evaluates the detectability of the phantom array and stroboscopic effects during light source motion, eye movement and their combination, using time modulated light-emitting diode light sources. It is well known that the phantom array can be observed when time-modulated light sources are observed during saccadic eye movements. We investigated whether light source motion can cause similar effects when the subject has fixed eyes. In addition, we estimated the detectability threshold frequency for the combination of stroboscopic effect and the phantom array, which is named the stroboscopic-phantom array effect, during two eye movements in opposite directions under one directional rotating light source with variable speed. Our results indicate that one of the most important factors for the stroboscopic-phantom array effect is eye movement speed relative to the speed of the light source. Therefore, time-modulated moving light sources induce a stroboscopic effect in subjects with fixed eyes that is similar to the stroboscopic-phantom array effect observed during saccadic eye movement. Our findings are likely to be useful for predicting the stroboscopic effect and the stroboscopic-phantom array effect during the fast motion of time-modulated LED light sources, like multi-functional rear lamps, in automotive lighting applications.
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Maslovat, Dana, Nicola J. Hodges, Romeo Chua, and Ian M. Franks. "Motor preparation of spatially and temporally defined movements: evidence from startle." Journal of Neurophysiology 106, no. 2 (August 2011): 885–94. http://dx.doi.org/10.1152/jn.00166.2011.
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Previous research has shown that the preparation of a spatially targeted movement performed at maximal speed is different from that of a temporally constrained movement ( Gottlieb et al. 1989b ). In the current study, we directly examined preparation differences in temporally vs. spatially defined movements through the use of a startling stimulus and manipulation of the task goals. Participants performed arm extension movements to one of three spatial targets (20°, 40°, 60°) and an arm extension movement of 20° at three movement speeds (slow, moderate, fast). All movements were performed in a blocked, simple reaction time paradigm, with trials involving a startling stimulus (124 dB) interspersed randomly with control trials. As predicted, spatial movements were modulated by agonist duration and timed movements were modulated by agonist rise time. The startling stimulus triggered all movements at short latencies with a compression of the kinematic and electromyogram (EMG) profile such that they were performed faster than control trials. However, temporally constrained movements showed a differential effect of movement compression on startle trials such that the slowest movement showed the greatest temporal compression. The startling stimulus also decreased the relative timing between EMG bursts more for the 20° movement when it was defined by a temporal rather than spatial goal, which we attributed to the disruption of an internal timekeeper for the timed movements. These results confirm that temporally defined movements were prepared in a different manner from spatially defined movements and provide new information pertaining to these preparation differences.
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LaRue, Jacques. "Initial Learning of Timing in Combined Serial Movements and a No-Movement Situation." Music Perception 22, no. 3 (2005): 509–30. http://dx.doi.org/10.1525/mp.2005.22.3.509.
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We investigate differences in timing errors in a task that imitated the movement sequence of a cello player. We trained a group of 17 young adults to perform a sequence of linear reversal movements of different lengths but with a constant movement time. Thus, each segment required the movement speed to be changed. The sequence had to be performed with fluidity, except for a �no-movement� segment that was embedded in the movement series. Feedback on timing was given for each segment. Results from this experiment show that the no-movement segment is more variable than any of the movement segments. There was no significant correlation between the timing errors of the successive movements and the timing error of the pause. These results provide further evidence in favor of two distinct timing processes: one used for continuous movements and one used for no-movement and discontinuous movements.
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Corcos, D. M., G. L. Gottlieb, and G. C. Agarwal. "Organizing principles for single-joint movements. II. A speed-sensitive strategy." Journal of Neurophysiology 62, no. 2 (August 1, 1989): 358–68. http://dx.doi.org/10.1152/jn.1989.62.2.358.
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1. Normal human subjects made discrete flexions of the elbow over a fixed distance in the horizontal plane from a stationary initial position to a visually defined target. We measured joint angle, acceleration, and electromyograms (EMGs) from two agonist and two antagonist muscles. 2. Changes in movement speed were elicited either by explicit instruction to the subject or by adjusting the target width. Instructions always required accurately stopping in the target zone. 3. Peak inertial torques and accelerations, movement times, and integrated EMGs were all highly correlated with speed. We show that inertial torque can be used as a linking variable that is almost sufficient to explain all correlations between the task, the EMG, and movement kinematics. 4. When subjects perform tasks that require control of movement speed, they adjust the rate at which torque is developed by the muscles. This rate is modulated by the way in which the muscles are activated. The rate at which joint torque develops is correlated with the rate at which the agonist EMG rises as well as with integrated EMG. 5. The antagonist EMG shows two components. The latency of the first is 30-50 ms and independent of movement dynamics. The latency of the second component is proportional to movement time. The rate of rise and area of both components scale with torque. 6. We propose organizing principles for the control of single-joint movements in which tasks are performed by one of two strategies. These are called speed-insensitive and speed-sensitive strategies. 7. A model is proposed in which movements made under a speed-sensitive strategy are executed by controlling the intensity of an excitation pulse delivered to the motoneuron pool. The effect is to regulate the rate at which joint torque, and consequently acceleration, increases. 8. Movements of variable distance, speed, accuracy, and load are shown to be controlled by one of two consistent sets of rules for muscle activation. These rules apply to the control of both the agonist and antagonist muscles. Rules of activation lead to distinguishable patterns of EMG and torque development. All observable changes in movement kinematics are explained as deterministic consequences of these effects.
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Qin, Wei, Baotong Cui, and Zhengxian Jiang. "Finite-Time Control of One Dimensional Crowd Evacuation System." Journal of Advanced Transportation 2019 (August 5, 2019): 1–9. http://dx.doi.org/10.1155/2019/6597360.
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This paper pertains to the study of finite-time control of one dimensional crowd evacuation system. Benefiting from the research of fluid dynamics and vehicle traffic, a one dimensional crowd evacuation system is constructed, whose density-velocity relationship is represented by a diffusion model. In order to deal with the nondirectionality of crowd movement, the free flow speed is chosen as a control variable. Since the control variable is included in a partial derivative, it increases the difficulty of designing the controller. In this paper, finite-time controller is designed, which not only guarantees the effective evacuation, but also obtains the estimation of evacuation time. Then, finite-time tracking problem is solved, which makes the density converge to a given density. Finally, numerical examples illustrate the effectiveness of the controllers.
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Loktev, Alexey Alexeevich, Vadim Vadimovich Korolev, Irina Viktorovna Shishkina, and Mikhail Evgenyevich Berezovskiy. "Calculation of the speed of movement on the side track for flat grades of switches." Transport of the Urals, no. 2 (2020): 52–56. http://dx.doi.org/10.20291/1815-9400-2020-2-52-56.
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There is a need to speed up the design and implementation of switches on the operated railway network, which can significantly increase the allowed speed of trains, especially on the side track. One of the starting points in the design of switches for high speeds is to provide passengers with a comfortable ride when the train is moving on a side track by limiting the values of the so-called centrifugal acceleration and the increment (change) of the centrifugal acceleration per unit of time (second). If it is necessary to implement the speed of movement on the switch to the side track over 50 km/h, the main factor in determining the radius of the transfer curve under the conditions of driving comfort is to limit the amount of increment (change) of the centrifugal acceleration per unit of time (second). Based on this, when designing switches for high speeds, it is advisable to use curves of variable radius as a translation curve.
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Dupuis, Frédérique, Gisela Sole, Craig Wassinger, Mathieu Bielmann, Laurent J. Bouyer, and Jean-Sébastien Roy. "Fatigue, induced via repetitive upper-limb motor tasks, influences trunk and shoulder kinematics during an upper limb reaching task in a virtual reality environment." PLOS ONE 16, no. 4 (April 8, 2021): e0249403. http://dx.doi.org/10.1371/journal.pone.0249403.
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Background Efficient shoulder movement depends on the ability of central nervous system to integrate sensory information and to create an appropriate motor command. Various daily encountered factors can potentially compromise the execution of the command, such as fatigue. This study explored how fatigue influences shoulder movements during upper limb reaching. Methods Forty healthy participants were randomly assigned to one of two groups: Control or Fatigue Group. All participants completed an upper limb reaching task at baseline and post-experimental, during which they reached four targets located at 90° of shoulder abduction, 90° external rotation at 90° abduction, 120° scaption, and 120° flexion in a virtual reality environment. Following the baseline phase, the Fatigue Group completed a shoulder fatigue protocol, while Controls took a 10-minute break. Thereafter, the reaching task was repeated. Upper limb kinematic (joint angles and excursions) and spatiotemporal (speed and accuracy) data were collected during the reaching task. Electromyographic activity of the anterior and middle deltoids were also collected to characterize fatigue. Two-way repeated-measures ANOVA were performed to determine the effects of Time, Group and of the interaction between these factors. Results The Fatigue group showed decreased mean median power frequency and increased electromyographic amplitudes of the anterior deltoid (p < 0.05) following the fatigue protocol. Less glenohumeral elevation, increased trunk flexion and rotation and sternoclavicular elevation were also observed in the Fatigue group (Group x Time interaction, p < 0.05). The Control group improved their movement speed and accuracy in post-experimental phase, while the Fatigue group showed a decrease of movement speed and no accuracy improvement (Group x Time interaction, p < 0.05). Conclusion In a fatigued state, changes in movement strategy were observed during the reaching task, including increased trunk and sternoclavicular movements and less glenohumeral movement. Performance was altered as shown by the lack of accuracy improvement over time and a decrease in movement speed in the Fatigue group.
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Filimonikhin, Gennadiy, Vladimir Pirogov, Maksim Hodunko, Ruslan Kisilov, and Vitalii Mazhara. "The dynamics of a resonance single-mass vibratory machine with a vibration exciter of targeted action that operates on the Sommerfeld effect." Eastern-European Journal of Enterprise Technologies 3, no. 7 (111) (June 17, 2021): 51–58. http://dx.doi.org/10.15587/1729-4061.2021.233960.
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This paper reports a study into the dynamics of a vibratory machine composed of a viscoelastically-fixed platform that can move vertically and two identical inertial vibration exciters. The vibration exciters' bodies rotate at the same angular velocities in opposite directions. The bodies host a single load in the form of a ball, roller, or pendulum. The loads' centers of mass can move relative to the bodies in a circle with a center on the axis of rotation. The loads' relative movements are hindered by the forces of viscous resistance. It was established that a vibratory machine theoretically possesses the following: – one to three oscillatory modes of movement under which loads get stuck at almost constant angular velocity and generate total unbalanced mass in the vertical direction only; – a no-oscillation mode under which loads rotate synchronously with the bodies and generate total unbalanced mass in the horizontal direction only. At the same time, only one oscillatory mode is resonant and exists at the above-the-resonance speeds of body rotation, lower than some characteristic speed. At the bodies' rotation speeds: ‒ pre-resonant; there is a globally asymptotically stable (the only existing) mode of load jams; ‒ above-the-resonance, lower than the characteristic velocity; there are locally asymptotically stable regimes ‒ both the resonance mode of movement of a vibratory machine and a no-oscillations mode; ‒ exceeding the characteristic velocity: there is a globally asymptotically stable no-oscillations mode. Computational experiments have confirmed the results of theoretical research. At the same time, it was additionally established that it would suffice, to enter a resonant mode of movement, to slowly accelerate the bodies of vibration exciters to the above-the-resonance speed, less than the characteristic speed. The results reported here could be interesting both for the theory and practice of designing new vibratory machines
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Adesta, Erry Yulian Triblas, and Muataz H. F. Al Hazza. "Machining Time Simulation in High Speed Hard Turning." Advanced Materials Research 264-265 (June 2011): 1102–6. http://dx.doi.org/10.4028/www.scientific.net/amr.264-265.1102.
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High speed hard turning is an advanced manufacturing technology that reduces the machining time because of two reasons; reducing the manufacturing steps and increasing the cutting speed. This new approach needs an economical justification; one of the main economical factors is the machining time. The machining time was breaking down into three main parts; productive time, non productive time, and preparation time. By using matlab Simulink, a new program was developed for machining time allowing the manufacturer to find rapidly the values of cutting time parameters and gives the management the opportunity to modify the processing parameters to achieve the optimum time by using the optimum cutting parameters. Table 1: Nomenclature d Depth of cut M T total machining time pmv t Total movement time D Work piece diameter h t handling time pch t Total Tool changing time f Feed rate tc t tool changing time pre t Total preparing time z e Engagement distance on Z-axis ch t Tool changing time per piece, prg t Programming time x e Degagement distance on X-axis am t Machine allowance time su t Set up time k Number of passes ao t Operator allowance time sum t Machine set up L Tool life a t Allowance time sut t Tool set up l Work piece length o t Tool movement at the rapid speed suw t Work piece set up N Spindle speed oA t From zero point to cutting point TH Tool hardness tool n No. of tool posts in the turret p t Total productive time o X tidy of the O t point o1 p Initial position of the turret. o Z = abciss of the O t point w Work piece weigh o2 p Position of the used tool c V Cutting speed c w Width of cutting speed r Rotation speed of the turret f V Feeding speed tool n no. of tool in the turret c t Cutting time o V Rapid speed speed r : Turret rotation speed
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Guigon, Emmanuel, Oussama Chafik, Nathanaël Jarrassé, and Agnès Roby-Brami. "Experimental and theoretical study of velocity fluctuations during slow movements in humans." Journal of Neurophysiology 121, no. 2 (February 1, 2019): 715–27. http://dx.doi.org/10.1152/jn.00576.2018.
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Moving smoothly is generally considered as a higher-order goal of motor control and moving jerkily as a witness of clumsiness or pathology, yet many common and well-controlled movements (e.g., tracking movements) have irregular velocity profiles with widespread fluctuations. The origin and nature of these fluctuations have been associated with the operation of an intermittent process but in fact remain poorly understood. Here we studied velocity fluctuations during slow movements, using combined experimental and theoretical tools. We recorded arm movement trajectories in a group of healthy participants performing back-and-forth movements at different speeds, and we analyzed velocity profiles in terms of series of segments (portions of velocity between 2 minima). We found that most of the segments were smooth (i.e., corresponding to a biphasic acceleration) and had constant duration irrespective of movement speed and linearly increasing amplitude with movement speed. We accounted for these observations with an optimal feedback control model driven by a staircase goal position signal in the presence of sensory noise. Our study suggests that one and the same control process can explain the production of fast and slow movements, i.e., fast movements emerge from the immediate tracking of a global goal position and slow movements from the successive tracking of intermittently updated intermediate goal positions. NEW & NOTEWORTHY We show in experiments and modeling that slow movements could result from the brain tracking a sequence of via points regularly distributed in time and space. Accordingly, slow movements would differ from fast movement by the nature of the guidance and not by the nature of control. This result could help in understanding the origin and nature of slow and segmented movements frequently observed in brain disorders.
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Cooper, Jr., William E., and Chad S. Smith. "Costs and economy of autotomy for tail movement and running speed in the skink Trachylepis maculilabris." Canadian Journal of Zoology 87, no. 5 (May 2009): 400–406. http://dx.doi.org/10.1139/z09-024.
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Economy of autotomy (shedding less than complete tails) is advantageous via retention of ability to autotomize and reduction of costs, including lipid loss, regeneration, and decreased social status. We studied its effects on predator-distracting tail movements and running speed in the speckle-lipped mabuya ( Trachylepis maculilabris (Boettger, 1913)) by removing fractions of the autotomizable portion. Distance moved was shorter for autotomized tail segments one third of the total tail length than for longer segments. Movement duration did not vary with proportion removed. Longer movement suggests that shedding longer segments improves ability to distract predators, enhances difficulty of capturing a tail, and may require longer handling time. Tails were difficult to break in regenerated sections and did not move when broken. The lack of movement of regenerated portions after separation suggests permanent loss of capacity to distract predators. Decreased speed was confirmed as a cost of autotomy in lizards that lost at least two thirds of their tail. In lizards that lost one third of tails speed was intermediate to that of intact lizards and those that lost more. Graded decrease in speed as proportional loss increases is consistent with progressive loss of a counterweight that reduces lateral motion while running. Economy of autotomy entails trade-offs between immediate and long-term escape ability.
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Yin, Henry H. "Action, time and the basal ganglia." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1637 (March 5, 2014): 20120473. http://dx.doi.org/10.1098/rstb.2012.0473.
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The ability to control the speed of movement is compromised in neurological disorders involving the basal ganglia, a set of subcortical cerebral nuclei that receive prominent dopaminergic projections from the midbrain. For example, bradykinesia, slowness of movement, is a major symptom of Parkinson's disease, whereas rapid tics are observed in patients with Tourette syndrome. Recent experimental work has also implicated dopamine (DA) and the basal ganglia in action timing. Here, I advance the hypothesis that the basal ganglia control the rate of change in kinaesthetic perceptual variables. In particular, the sensorimotor cortico-basal ganglia network implements a feedback circuit for the control of movement velocity. By modulating activity in this network, DA can change the gain of velocity reference signals. The lack of DA thus reduces the output of the velocity control system which specifies the rate of change in body configurations, slowing the transition from one body configuration to another.
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Summerside, Erik M., Reza Shadmehr, and Alaa A. Ahmed. "Vigor of reaching movements: reward discounts the cost of effort." Journal of Neurophysiology 119, no. 6 (June 1, 2018): 2347–57. http://dx.doi.org/10.1152/jn.00872.2017.
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Making a movement may be thought of as an economic decision in which one spends effort to acquire reward. Time discounts reward, which predicts that the magnitude of reward should affect movement vigor: we should move faster, spending greater effort, when there is greater reward at stake. Indeed, saccade peak velocities are greater and reaction-times shorter when a target is paired with reward. In this study, we focused on human reaching and asked whether movement kinematics were affected by expectation of reward. Participants made out-and-back reaching movements to one of four quadrants of a 14-cm circle. During various periods of the experiment only one of the four quadrants was paired with reward, and the transition from reward to nonreward status of a quadrant occurred randomly. Our experiment design minimized dependence of reward on accuracy, granting the subjects wide latitude in self-selecting their movement speed, amplitude, and variability. When a quadrant was paired with reward, reaching movements had a shorter reaction time, higher peak velocity, and greater amplitude. Despite this greater vigor, movements toward the rewarded quadrant suffered from less variability: both reaction times and reach kinematics were less variable when there was expectation of reward. Importantly, the effect of reward on vigor was specific to the movement component that preceded the time of reward (outward reach), not the movement component that followed it (return reach). Our results suggest that expectation of reward not only increases vigor of human reaching but also decreases its variability. NEW & NOTEWORTHY Movements may be thought of as an economic transaction where the vigor of the movement represents the effort that the brain is willing to expend to acquire a rewarding state. We show that in reaching, reward discounts the cost of effort, producing movements with shorter reaction time, higher velocity, greater amplitude, and reduced reaction-time variability. These results complement earlier observations in saccades, suggesting a common principle of economics across modalities of motor control.
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Mokhirev, A. P., K. P. Rukomojnikov, P. M. Mazurkin, and N. A. Bragina. "Verification of timber carriers speed models movement depending on natural and production factors." FORESTRY BULLETIN 25, no. 2 (April 2021): 108–15. http://dx.doi.org/10.18698/2542-1468-2021-2-108-115.
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One of the key production parameters of the forest transport process is the speed of movement of timber carriers when removing wood from the upper warehouse. This speed determines the maximum possible volume of prepared and exported wood. Many natural and industrial factors affect the speed of a timber truck. The speed of transport depends on the traffic conditions on the roads, which are significantly complicated by adverse weather events. Scientists have identified laws in changing the speed modes of moving vehicles based on practical observations of individual road sections. To identify the dependence of the speed of a logging truck on 31 factors under consideration, 162 observations were made on measurements of the speed of logging trucks in various natural and industrial conditions. Mathematical models have been developed for calculating the speed of a logging vehicle, taking into account natural and industrial factors. Verification of the obtained nonlinear and wave regression models is the goal of this article. To verify the models, an additional experiment was carried out to compare the calculated models of speed modes of timber carriers with the actual ones. During the experiment, we used data on the speed of a logging truck when transporting wood from the upper warehouse in the cutting area to the raw material warehouse of a wood processing enterprise on the territory of the Yenisei forest district of the Krasnoyarsk territory. The logging road was divided into six sections, each of which was divided into elementary sections by slopes. At each section, the parameters that affect the speed of the timber carrier were determined using previously identified multi-factor equations, and the estimated time of cargo delivery by the timber carrier to the destination was obtained. Comparing the actual travel time with the calculated one based on previously identified equations for a timber truck with cargo on the way from the upper warehouse to the point of wood delivery, it was found that the estimated time of cargo delivery coincides with the actual one with an error of 7 %, and this is an acceptable norm(less than 30 %) for technological processes. Thus, the obtained results of testing multi-factor models can be considered reliable.
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Arsyad, Arsyad. "Fondasi Ontologi Mullȃ Sadrȃ: Sebuah Tinjauan Filsafat." SIASAT 3, no. 2 (July 16, 2019): 1–13. http://dx.doi.org/10.33258/siasat.v2i2.16.
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Because a movement is an achievement of new actuality and perfection through motion, every movement is inevitably a strengthening process and causes the movement of something more perfect. Here we need to distinguish two points, one, the process of refinement of a motion and the other is the process of refinement of a moving subject. The moving agent can be constant reaching perfection through movement but the speed of the process can be that the speed of the improvement process increases or decreases or remains. Constant speed and deceleration do not conflict with the process of refinement in a movement. Examples of the process of moving an apple to be sweeter speed more sweetness decreases but still at each time sweeter than before even though the change is slowing down. Consequently, assuming that in a motion, the motion causes a refinement process for the moving agent does not conflict with assuming a reduced speed of the process
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Herfst, Lucas J., and Michael Brecht. "Whisker Movements Evoked by Stimulation of Single Motor Neurons in the Facial Nucleus of the Rat." Journal of Neurophysiology 99, no. 6 (June 2008): 2821–32. http://dx.doi.org/10.1152/jn.01014.2007.
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The lateral facial nucleus is the sole output structure whose neuronal activity leads to whisker movements. To understand how single facial nucleus neurons contribute to whisker movement we combined single-cell stimulation and high-precision whisker tracking. Half of the 44 stimulated neurons gave rise to fast whisker protraction or retraction movement, whereas no stimulation-evoked movements could be detected for the remainder. Direction, speed, and amplitude of evoked movements varied across neurons. Protraction movements were more common than retraction movements ( n = 16 vs. n = 4), had larger amplitudes (1.8 vs. 0.3° for single spike events), and most protraction movements involved only a single whisker, whereas most retraction movements involved multiple whiskers. We found a large range in the amplitude of single spike-evoked whisker movements (0.06–5.6°). Onset of the movement occurred at 7.6 (SD 2.5) ms after the spike and the time to peak deflection was 18.2 (SD 4.3) ms. Each spike reliably evoked a stereotyped movement. In two of five cases peak whisker deflection resulting from consecutive spikes was larger than expected when based on linear summation of single spike-evoked movement profiles. Our data suggest the following coding scheme for whisker movements in the facial nucleus. 1) Evoked movement characteristics depend on the identity of the stimulated neuron (a labeled line code). 2) The facial nucleus neurons are heterogeneous with respect to the movement properties they encode. 3) Facial nucleus spikes are translated in a one-to-one manner into whisker movements.
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Yan, Jin H., Richard N. Hinrichs, V. Gregory Payne, and Jerry R. Thomas. "Normalized Jerk: A Measure to Capture Developmental Characteristics of Young Girls' Overarm Throwing." Journal of Applied Biomechanics 16, no. 2 (May 2000): 196–203. http://dx.doi.org/10.1123/jab.16.2.196.
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This study was designed to examine Ihe developmental differences in the speed and smoothness of arm movement during overarm throwing. The second purpose of this investigation was to evaluate whether jerk is a useful measure in understanding children's overarm throwing. Fifty-one girls, aged 3 to 6 years, voluntarily participated in the study. Each subject threw tennis balls as hard as she could toward a large target on the wall. A 2-camera video system was used to obtain 3-D coordinates of the hand and ball using the DLT algorithm. The variables of velocity and jerk (for the hand and ball) served as the movement outcome measures. The age-associated differences in velocity and normalized jerk (absolute jerk standardized relative to movement time and distance) were examined by ANOVAs. The results supported the hypothesis that the older subjects demonstrated faster and smoother hand movements than their younger counterparts during the forward acceleration phase (from the beginning of forward motion to ball release). In addition, the correlation results indicated thai increased hand movement speed was associated with decreased movement jerk in older subjects, whereas increased hand speed was associated with increased jerk in younger subjects. The findings suggest that examining the jerk parameter (normalized or absolute jerk) is a useful and alternative approach to capture the variance of hand movement execution for children's overarm throwing.
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Johnson, Walter W., and Sandra G. Hart. "Step Tracking Shrinking Targets." Proceedings of the Human Factors Society Annual Meeting 31, no. 2 (September 1987): 248–52. http://dx.doi.org/10.1177/154193128703100225.
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Four models describing how people might acquire targets that dynamically vary in size were examined; two that described movement speed as a simple function of target size (either initial or final) and two that described movement speed as a function of the predicted size of the targets at a fixed time in the future (one was referenced to the beginning of the reaction time phase, and the other to the end of this phase). It was found that movement time was best described as a function of a size prediction made at the end, rather than the start, of the reaction time phase. Subjective workload ratings primarily reflected the total amount of time needed to acquire the targets rather than the time pressure imposed by the diminishing size of these targets.
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Tanaka, Hirokazu, John W. Krakauer, and Ning Qian. "An Optimization Principle for Determining Movement Duration." Journal of Neurophysiology 95, no. 6 (June 2006): 3875–86. http://dx.doi.org/10.1152/jn.00751.2005.
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Movement duration is an integral component of motor control, but nearly all extant optimization models of motor planning prefix duration instead of explaining it. Here we propose a new optimization principle that predicts movement duration. The model assumes that the brain attempts to minimize movement duration under the constraint of meeting an accuracy criterion. The criterion is task and context dependent but is fixed for a given task and context. The model determines a unique duration as a trade-off between speed (time optimality) and accuracy (acceptable endpoint scatter). We analyzed the model for a linear motor plant, and obtained a closed-form equation for determining movement duration. By solving the equation numerically with specific plant parameters for the eye and arm, we found that the model can reproduce saccade duration as a function of amplitude (the main sequence), and arm-movement duration as a function of the ratio of target distance to size (Fitts's law). In addition, it explains the dependency of peak saccadic speed on amplitude and the dependency of saccadic duration on initial eye position. Furthermore, for arm movements, the model predicts a scaling relationship between peak velocity and distance and a reduction in movement duration with a moderate increase in viscosity. Finally, for a linear plant, our model predicts a neural control signal identical to that of the minimum-variance model set to the same movement duration. This control signal is a smooth function of time (except at the endpoint), in contrast to the discontinuous bang–bang control found in the time-optimal control literature. We suggest that one aspect of movement planning, as revealed by movement duration, may be to assign an endpoint accuracy criterion for a given task and context.
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Kramer, Donald L., Robert L. Mclaughlin, and James W. A. Grant. "Individual Variation and Alternative Patterns of Foraging Movements in Recently-Emerged Brook Charr (Salvelinus Fontinalis)." Behaviour 120, no. 3-4 (1992): 286–301. http://dx.doi.org/10.1163/156853992x00642.
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AbstractRecently-emerged juvenile brook charr foraging in relatively homogeneous, clear, still-water pools displayed significant interindividual variation in the proportion of search time spent moving, the average speed during search, the average speed during periods of moving search, and the distance moved during pursuit of prey. The frequency distribution for interindividual variation in the proportion of time spent moving was bimodal, but distributions for the other movement parameters were not. Thus, in the field, young charr tended to specialize at one of two alternative movement patterns differing primarily in the proportion of time spent moving. The movement parameters were all positively correlated, but correlations between the proportion of time spent moving, the speed while moving, and pursuit distance were small enough (r2's < 0.30) to suggest that different aspects of search mode may vary relatively independently. Our findings have three implications for studies of search mode. First, intraspecific variation in search mode need not be only a response to environmental change, but can occur in the same environment at the same time. Second, frequency distributions of movement parameters offer a more objective base than do arbitrary classifications for determining how many types of foragers are present. Third, studies using different movement parameters to distinguish between alternative search modes (e.g. sitting-and-waiting and actively searching) may not be directly comparable.
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Tresilian, J. R., and J. H. Houseman. "Systematic Variation in Performance of an Interceptive Action with Changes in the Temporal Constraints." Quarterly Journal of Experimental Psychology Section A 58, no. 3 (April 2005): 447–66. http://dx.doi.org/10.1080/02724980343000954.
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People are highly skilled at intercepting moving objects and are capable of remarkably accurate timing. The timing accuracy required depends upon the period of time for which contact with a moving target is possible—the “time window” for successful interception. Studies of performance in an experimental interception task that allows this time window to be manipulated suggest that people change aspects of their performance (movement time, MT, and movement speed) in response to changes in the time window. However, this research did not establish whether the observed changes in performance were the results of a response to the time window per se or of independent responses to the quantities defining the time window (the size and speed of a moving target). Experiment 1 was designed to resolve this issue. The speed and size of the target were both varied, resulting in variations in the time window; MT was the primary dependent measure. Predictions of the hypothesis that people respond directly to changes in the time window were verified. Predictions of the alternative hypothesis that responses to changes in target speed and size are independent of one another were not supported. Experiment 2 examined how the type of performance change observed in Experiment 1 was affected by changing the time available for executing the interception. The time available and the target speed were varied, and MT was again the primary dependent measure. MT was smaller when there was less time available, and the effect of target speed (and hence the time window) on MT was also smaller, becoming undetectable at the shortest available time (0.4 s). The results of the two experiments are interpreted as providing information about the “rule” used to preprogramme movement parameters in anticipatory interceptive actions.
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Petersen, Carl, David B. Pyne, Marc R. Portus, Stuart Karppinen, and Brian Dawson. "Variability in Movement Patterns During One Day Internationals by a Cricket Fast Bowler." International Journal of Sports Physiology and Performance 4, no. 2 (June 2009): 278–81. http://dx.doi.org/10.1123/ijspp.4.2.278.
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Purpose:The time-motion characteristics and the within-athlete variability in movement patterns were quantified for the same male fast bowler playing One Day International (ODI) cricket matches (n = 12).Methods:A number of different time motion characteristics were monitored using a portable 5-Hz global positioning system (GPS) unit (Catapult, Melbourne, Australia).Results:The bowler’s mean workload per ODI was 8 ± 2 overs (mean ± SD). He covered a total distance of 15.9 ± 2.5 km per game; 12 ± 3% or 1.9 ± 0.2 km was striding (0.8 ± 0.2 km) or sprinting (1.1 ± 0.2 km), whereas 10.9 ± 2.1 km was spent walking. One high-intensity (running, striding, or sprinting) repetition (HIR) occurred every 68 ± 12 s, and the average duration of a HI effort was 2.7 ± 0.1 s. The player also completed 66 ± 11 sprints per game; mean sprint distance was 18 ± 3 m and maximum sprinting speed 8.3 ± 0.9 m·s−1.Conclusions:The movement patterns of this fast bowler were a combination of highly intermittent activities of variable intensity on the base of ~16 km per game. This information provides insight for conditioning coaches to determine the physical demands and to adapt the training and recovery processes of ODI fast bowlers.
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Johansson, Anna-Maria, Helena Grip, Louise Rönnqvist, Jonas Selling, Carl-Johan Boraxbekk, Andrew Strong, and Charlotte K. Häger. "Influence of visual feedback, hand dominance and sex on individuated finger movements." Experimental Brain Research 239, no. 6 (April 19, 2021): 1911–28. http://dx.doi.org/10.1007/s00221-021-06100-0.
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AbstractThe ability to perform individual finger movements, highly important in daily activities, involves visual monitoring and proprioception. We investigated the influence of vision on the spatial and temporal control of independent finger movements, for the dominant and non-dominant hand and in relation to sex. Twenty-six healthy middle-aged to old adults (M age = 61 years; range 46–79 years; females n = 13) participated. Participants performed cyclic flexion–extension movements at the metacarpophalangeal joint of one finger at a time while keeping the other fingers as still as possible. Movements were recorded using 3D optoelectronic motion technique (120 Hz). The movement trajectory distance; speed peaks (movement smoothness); Individuation Index (II; the degree a finger can move in isolation from the other fingers) and Stationarity Index (SI; how still a finger remains while the other fingers move) were extracted. The main findings were: (1) vision only improved the II and SI marginally; (2) longer trajectories were evident in the no-vision condition for the fingers of the dominant hand in the female group; (3) longer trajectories were specifically evident for the middle and ring fingers within the female group; (4) females had marginally higher II and SI compared with males; and (5) females had fewer speed peaks than males, particularly for the ring finger. Our results suggest that visual monitoring of finger movements marginally improves performance of our non-manipulative finger movement task. A consistent finding was that females showed greater independent finger control compared with males.
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Gribble, Paul L., David J. Ostry, Vittorio Sanguineti, and Rafael Laboissière. "Are Complex Control Signals Required for Human Arm Movement?" Journal of Neurophysiology 79, no. 3 (March 1, 1998): 1409–24. http://dx.doi.org/10.1152/jn.1998.79.3.1409.
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Gribble, Paul L., David J. Ostry, Vittorio Sanguineti, and Rafael Laboissière. Are complex control signals required for human arm movement? J. Neurophysiol. 79: 1409–1424, 1998. It has been proposed that the control signals underlying voluntary human arm movement have a “complex” nonmonotonic time-varying form, and a number of empirical findings have been offered in support of this idea. In this paper, we address three such findings using a model of two-joint arm motion based on the λ version of the equilibrium-point hypothesis. The model includes six one- and two-joint muscles, reflexes, modeled control signals, muscle properties, and limb dynamics. First, we address the claim that “complex” equilibrium trajectories are required to account for nonmonotonic joint impedance patterns observed during multijoint movement. Using constant-rate shifts in the neurally specified equilibrium of the limb and constant cocontraction commands, we obtain patterns of predicted joint stiffness during simulated multijoint movements that match the nonmonotonic patterns reported empirically. We then use the algorithm proposed by Gomi and Kawato to compute a hypothetical equilibrium trajectory from simulated stiffness, viscosity, and limb kinematics. Like that reported by Gomi and Kawato, the resulting trajectory was nonmonotonic, first leading then lagging the position of the limb. Second, we address the claim that high levels of stiffness are required to generate rapid single-joint movements when simple equilibrium shifts are used. We compare empirical measurements of stiffness during rapid single-joint movements with the predicted stiffness of movements generated using constant-rate equilibrium shifts and constant cocontraction commands. Single-joint movements are simulated at a number of speeds, and the procedure used by Bennett to estimate stiffness is followed. We show that when the magnitude of the cocontraction command is scaled in proportion to movement speed, simulated joint stiffness varies with movement speed in a manner comparable with that reported by Bennett. Third, we address the related claim that nonmonotonic equilibrium shifts are required to generate rapid single-joint movements. Using constant-rate equilibrium shifts and constant cocontraction commands, rapid single-joint movements are simulated in the presence of external torques. We use the procedure reported by Latash and Gottlieb to compute hypothetical equilibrium trajectories from simulated torque and angle measurements during movement. As in Latash and Gottlieb, a nonmonotonic function is obtained even though the control signals used in the simulations are constant-rate changes in the equilibrium position of the limb. Differences between the “simple” equilibrium trajectory proposed in the present paper and those that are derived from the procedures used by Gomi and Kawato and Latash and Gottlieb arise from their use of simplified models of force generation.
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Yao, Qian. "THE REACTION SPEED OF DIFFERENT TYPES OF TRAINING ON FENCING ATHLETES." Revista Brasileira de Medicina do Esporte 28, no. 2 (April 2022): 141–43. http://dx.doi.org/10.1590/1517-8692202228022021_0453.
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ABSTRACT Introduction: Fencing is a combat sport with fierce confrontation and variations in offense and defense. To a certain extent, speed is the decisive factor in winning the game. Objective: To explore the influence of different training methods on the reaction time of fencers. Method: 20 fencers were selected and divided into three groups with different fencing levels, in addition to one control group. The experimental groups trained in three 10-minute sessions a week. The control group trained for 3 hours in the afternoons, from Monday to Saturday. Results: After training, the experimental group fencers showed a highly significant difference in the selective response to foot movement (t=4.004, P=0.001<0.01). The simple reaction test of the fencers in the control group improved slightly after training, but it was not statistically significant (t=2.223, P=0.09>0.05). In the selective reaction time test without foot movement, the reaction time of the control group was significantly lower after training (t=3.450, P=0.026<0.05). Conclusion: Regardless of the student›s fencing level, different training methods can significantly improve their reaction time. Level of evidence II; Therapeutic studies - investigation of treatment results.
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Ghiasi, Pedram, Gholamhassan Najafi, Barat Ghobadian, and Ali Jafari. "Analytical and Numerical Solution for H-type Darrieus Wind Turbine Performance at the Tip Speed Ratio of Below One." International Journal of Renewable Energy Development 10, no. 2 (December 30, 2020): 269–81. http://dx.doi.org/10.14710/ijred.2021.33169.
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H-type Darrieus vertical axis wind turbines (VAWT) have omnidirectional movement capability and can get more power compared to other VAWTs at high tip speed ratios (𝜆). However, its disadvantages are self-starting inability and low generated power at 𝜆 less than 1. The performance of H-type Darrieus wind turbine at 𝜆<1 was studied using double multiple stream tube (DMST) model and two-dimensional computational fluid dynamic (CFD) simulation. In CFD simulation, the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations were used and the turbulence model was solved with SST k-ω model. The performance of fifteen various wind turbines was determined at fourteen wind velocities by two solution methods. The effect of chord length, solidity, Reynolds number and Height to Diameter (H/D) ratio were investigated on generated torque, power and the time required to reach 𝜆=0.1. Increasing in the moment of inertia due to the increasing in required time to reach 𝜆=0.1. In the low TSRs, the wind turbines can generate higher torque and power in high Re numbers and solidities. The required time was reduced by an increase in Re number and solidity. Finally, the best ratio of H/D of H-type Darrieus wind turbines was defined to improve the turbine performance.
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Dietz, R., and M. P. Heide-Jørgensen. "Movements and swimming speed of narwhals, Monodon monoceros, equipped with satellite transmitters in Melville Bay, northwest Greenland." Canadian Journal of Zoology 73, no. 11 (November 1, 1995): 2106–19. http://dx.doi.org/10.1139/z95-248.
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Positions were obtained for up to 100 days from nine narwhals, Monodon monoceros, representing both sexes and all age categories instrumented with satellite-linked UHF radio transmitters in Melville Bay (76°03′06″N, 61°14′90″W), northwest Greenland, in August – September 1993 and 1994. In both years all nine narwhals stayed within Melville Bay during the open-water portion of the tracking period. Most of the coastal positions obtained were inside the Melville Bay Wildlife Sanctuary. The narwhals also moved up to 100 km offshore to areas where water depths exceed 1000 m. There was no discernible relationship between tide and the movements of whales. By early to mid-October, the narwhals left Melville Bay and started migrating southwards along the continental slope, where water depths range from 500 to 1000 m. This southward movement ceased some 700 km farther south in late November, still in water with depths of 500–1000 m. The mean swimming speed of the whales during September varied between 2.9 and 8.2 km/h, calculated for intervals of 0.5–5 h between consecutive positions. No size- or sex-related pattern could be detected in swimming speeds, nor could any diurnal differences be found. The use of longer intervals between consecutive positions resulted in significantly lower calculated swimming speeds, suggesting that swimming speed will be underestimated if calculated over a longer time span. The mean swimming speed of one subadult and one adult male decreased significantly from 5.5 and 5.8 km/h in September to 2.7 km/h in November.
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McManus, Thomas Neil, and Assed Haddad. "Surface Air Movement: An Important Contributor to Ventilation of Isolated Subsurface Structures?" Infrastructures 4, no. 2 (May 9, 2019): 23. http://dx.doi.org/10.3390/infrastructures4020023.
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This study reports on near-surface airspeed measured using a fast-responding thermoanemometer during an investigation of ventilation of an isolated subsurface structure induced by natural forces. Air speed changes continuously, rapidly, and unpredictably when assessed on the time base of one or two seconds. Zero, the most common air speed, occurred in almost all tests throughout the year but especially during cool and cold months. The most probable non-zero air speed, 10.7 m/min (35 ft/min), occurred in all tests. This air speed is below the level of detection by the senses. The number of zero values and the height of the peak at 10.7 m/min follow a repetitive annual cycle. Isolated subsurface structures containing manhole covers share the characteristics of Helmholtz resonators. Grazing air flow across the opening to the exterior induces rotational air flow in the airspace of a Helmholtz resonator. Rotational flow in the airspace potentially influences the exchange of the confined atmosphere with the external one. Ventilation of the airspace occurs continuously and without cost and is potentially enhanced by the unique characteristics of the Helmholtz resonator excited by surface air movement. These results have immense importance and immediate applicability to worker safety.
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Zhu, Xin Cai, Teng Fei Hu, Lei Guo, Xiong Zhou, You Qing Ding, and Xing Deng. "The Study on the Performance of Two Drive Forms of Centrifugal Atomizer." Applied Mechanics and Materials 233 (November 2012): 324–27. http://dx.doi.org/10.4028/www.scientific.net/amm.233.324.
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High speed rotating centrifugal atomizer is the key part in the flue gas processing. The different driving form affects the atomizer's stability of high speed movement, atomization effect and the running life directly. For a long time, the transmission quality of belt drive or direct coupling drive is one of the focus issues. Based on the high speed centrifugal atomizer, this paper introduces the two commonly used driving forms of the atomizer, and compares their performance through the experiments.
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Gottlieb, G. L., D. M. Corcos, and G. C. Agarwal. "Organizing principles for single-joint movements. I. A speed-insensitive strategy." Journal of Neurophysiology 62, no. 2 (August 1, 1989): 342–57. http://dx.doi.org/10.1152/jn.1989.62.2.342.
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1. Normal human subjects made discrete elbow flexions and extensions in the horizontal plane from a stationary initial position to visually defined targets at different distances with a constant inertial load or made flexions to a visually defined target with different inertial loads. We measured joint angle, acceleration, and electromyograms (EMGs) from two agonist and two antagonist muscles. 2. Subjects were instructed to move their limbs accurately but quickly to the targets. Movements of greater distances or lesser loads were performed at higher velocities. 3. Peak inertial torque, acceleration and velocity, movement time, and integrated, rectified EMG were all highly correlated with the task variables, distance and inertial load. We show that peak inertial torque can be used as a linking variable that is almost sufficient to explain all correlations between the tasks, the EMG, and movement kinematics. 4. The rate at which subjects initially developed torque to accelerate their movements was invariant over changes in the value of either task variable. The rising phase of the agonist EMG was also independent of the distance or load moved. 5. Two components were distinguished in the antagonist EMG. The first had a relatively constant latency and amplitude. It terminated on the onset of the second and larger component at a latency that was delayed as both distance and load increased. 6. The integrated, rectified antagonist EMG was proportional to inertial load and peak decelerating torque for changes in inertial load. When target distance varied, proportionality between peak decelerating torque and antagonist EMG could be found if correction was made for the effects of muscle length on the torque-EMG relationship. 7. We propose organizing principles for the control of single-joint human movements in which tasks are performed by one of two strategies. These are called speed-insensitive and speed-sensitive strategies. 8. A model is described in which movements made under a speed-insensitive strategy are executed by controlling the duration and the relative timing of amplitude invariant patterns of activation to the spinal motoneuron pools.
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Lewek, Michael D., Carty H. Braun, Clint Wutzke, and Carol Giuliani. "The role of movement errors in modifying spatiotemporal gait asymmetry post stroke: a randomized controlled trial." Clinical Rehabilitation 32, no. 2 (July 27, 2017): 161–72. http://dx.doi.org/10.1177/0269215517723056.
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Objective: Current rehabilitation to improve gait symmetry following stroke is based on one of two competing motor learning strategies: minimizing or augmenting symmetry errors. We sought to determine which of those motor learning strategies best improves overground spatiotemporal gait symmetry. Design: Randomized controlled trial. Setting: Rehabilitation research lab. Subjects: In all, 47 participants (59 ± 12 years old) with chronic hemiparesis post stroke and spatiotemporal gait asymmetry were randomized to error augmentation, error minimization, or conventional treadmill training (control) groups. Interventions: To augment or minimize asymmetry on a step-by-step basis, we developed a responsive, “closed-loop” control system, using a split-belt instrumented treadmill that continuously adjusted the difference in belt speeds to be proportional to the patient’s current asymmetry. Main measures: Overground spatiotemporal asymmetries and gait speeds were collected prior to and following 18 training sessions. Results: Step length asymmetry reduced after training, but stance time did not. There was no group × time interaction. Gait speed improved after training, but was not affected by type of asymmetry, or group. Of those who trained to modify step length asymmetry, there was a moderately strong linear relationship between the change in step length asymmetry and the change in gait speed. Conclusion: Augmenting errors was not superior to minimizing errors or providing only verbal feedback during conventional treadmill walking. Therefore, the use of verbal feedback to target spatiotemporal asymmetry, which was common to all participants, appears to be sufficient to reduce step length asymmetry. Alterations in stance time asymmetry were not elicited in any group.
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Honma, Keisuke, Yuki Yano, Saki Yamamoto, Toshimitsu Ohmine, Hideyuki Wanaka, Kazuma Senzaki, Atsuki Kanayama, Hiroyuki Oonishi, and Akira Iwata. "Immediate Effects of Single-Session High-Velocity Training for Lateral Trunk Movement on Gait Function in Early Postoperative Patients after Total Hip Arthroplasty: A Nonrandomized Controlled Trial." Healthcare 10, no. 2 (January 28, 2022): 256. http://dx.doi.org/10.3390/healthcare10020256.
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Background: Total Hip Arthroplasty (THA) is an effective method for relieving pain and improving gait function. However, THA patients demonstrate slow gait speed at discharge. Rehabilitation programs after THA require the immediate improvement of gait speed early in the postoperative period. To examine the immediate effects of seated side tapping training (SSTT), which focuses on lateral trunk movement and movement velocity, on gait function in early postoperative THA patients, the methods were as follows: The SSTT group performed five repetitions of a task in which they moved their trunks laterally to alternately touch markers to their left and right side as quickly as possible 10 times in a seated position. One set of SSTT lasted approximately 3 min. The control group rested in a seated position for 10 min. Results: Significant interactions were observed for gait speed, stride time, and stride time coefficient of variability. The SSTT group demonstrated significant pre-post-intervention improvement in gait speed, stride time, and coefficient of variability. Conclusions: SSTT improved both gait speed and gait stability and can be performed easily and safely. Therefore, single-session high-velocity trunk training may be an effective method to improve gait function immediately in early postoperative THA patients.
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Cui, Hong Jun, and Li Jun Li. "Analysis on Warp’s Frictional Movement in the Heald Eye during Weaving Process." Advanced Materials Research 175-176 (January 2011): 490–95. http://dx.doi.org/10.4028/www.scientific.net/amr.175-176.490.
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Currently the abrasion and breakage of warp during the weaving process have become the key issue in high-speed weaving of non-shuttle looms. According to the experiment, the heald frame is the main zone where warp abrades. With the multiple effects of shedding and beating up, warp will make a frictional movement every time one weft is weaved, no matter which opening mode is used. These frequent frictional movements will cause warp’s surface damage, which leads to breakage. Therefore warp’s frequent frictional movement in the heald eye is the main factor causing warp’s breakage. By theoretically analyzing warp’s front and back elongation and tension while beating up, this paper establishes the formula of warp’s movement in the heald eye, and discusses the effect of weaving parameters on this movement, such as looming tension, warp line, opening time and geometric shedding size. This provides theoretical basis for solving the frictional issue reasonably. According to the result, by forming the shed with big tension, high back-rest, late shedding, long shed, fast opening and slow closing, the frictional movement of warp in the heald eye can be reduced during the weaving process. In this way, warp’s excessive abrasion can be avoided and its breakage will be lowered, so as to improve weaving efficiency.
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Latash, Mark L., and Irina L. Mikaelian. "A Logarithmic Speed-Difficulty Trade-off in Speech Production." Motor Control 15, no. 1 (January 2011): 52–67. http://dx.doi.org/10.1123/mcj.15.1.52.
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We explored the relations between task difficulty and speech time in picture description tasks. Six native speakers of Mandarin Chinese (CH group) and six native speakers or Indo-European languages (IE group) produced quick and accurate verbal descriptions of pictures in a self-paced manner. The pictures always involved two objects, a plate and one of the three objects (a stick, a fork, or a knife) located and oriented differently with respect to the plate in different trials. An index of difficulty was assigned to each picture. CH group showed lower reaction time and much lower speech time. Speech time scaled linearly with the log-transformed index of difficulty in all subjects. The results suggest generality of Fitts’ law for movement and speech tasks, and possibly for other cognitive tasks as well. The differences between the CH and IE groups may be due to specific task features, differences in the grammatical rules of CH and IE languages, and possible use of tone for information transmission.
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Jurkojć, Jacek, Piotr Wodarski, Robert Michnik, Wojciech Marszałek, Kajetan J. Słomka, and Marek Gzik. "The Use of Frequency Analysis as a Complementary and Explanatory Element for Time Domain Analysis in Measurements of the Ability to Maintain Balance." Journal of Human Kinetics 76, no. 1 (January 11, 2021): 117–29. http://dx.doi.org/10.2478/hukin-2021-0004.
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Abstract Assessment of human balance is one of the most common diagnostic tests, both in medical applications and during sports training. Many new methods of measuring are introduced in these studies; however, the analysis of results is still carried out mainly based on the values determined in the time domain – the average COP speed or the ellipse field of the prediction. The aim of the current work is to present the possibilities for the practical application of frequency analyses in assessment of the ability to maintain body balance as a method supplementing standard analyses. As part of the study, measurements of the ability to maintain balance in sensory conflict conditions introduced in the form of an oscillating, three-dimensional, virtual scenery were carried out. 27 healthy volunteers (13 women and 14 men) took part in the study. The three-dimensional scenery, presented by means of the Oculus system, oscillated in the sagittal plane with frequencies equal to 0.7 Hz and 1.4 Hz. The frequency value during the measurement was constant or changed in the middle of the test. Measurements were conducted on the FDM Zebris platform. The results were analyzed using developed coefficients determined on the basis of the Short-time Fourier transform (STFT). The use of frequency-domain analyses confirmed that in the COP movement, one can observe a cyclical component corresponding to following the scenery, as well as the appearance of other cyclical components whose observation is important in terms of assessing the ability to maintain balance. It has been shown that the changes in the average COP speed that occur during the measurement can result from changes related to the movement of following the scenery as well as additional body movements indicating a greater or lesser loss of balance. It has been shown that there are differences in the COP movement provoked by the movement of the surrounding scenery, which depend on the parameters of the introduced disturbances – something that can only be observed in results obtained in the frequency domain. The conducted research shows that in measurements involving the ability to maintain one’s balance conducted in sensory conflict conditions, standard time-domain analyses should be supplemented with other types of data analysis, e.g. frequency domain analyses.
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Shepeleva, Elena Vitalyevna, Vladimir Anatolyevich Gorodokin, Vladimir Dmitrievich Shepelev, and Zlata Viktorovna Almetova. "Provision of non-stop movement of organized traffic flow on the node of road network on the basis of application of computer vision and dynamic road signs." Transport of the Urals, no. 4 (2020): 60–67. http://dx.doi.org/10.20291/1815-9400-2020-4-60-67.
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Increase of traffic capacity of road network in conditions of high density of traffic flows is one of the main priorities at organization of road traffic in big cities. A non-stop movement through the intersection by the «green wave» principle can become the most effective solution of the problem. But the existing methods of coordinated road traffic don’t take into account the stochasticity of arrival of extra-group vehicles to the intersection. The present investigation proposes a method of organization of non-stop movement of cars through intersections of road network with the use of computer vision and dynamic road signs. The method is based on analysis of actual road situation in real time mode from the street surveillance cameras. The use of YOLOv3 trained ultra-precise neural networks for the analysis of video stream allows identifying and classifying extra-group vehicles. The SORT tracker estimates speed and time of movement through the «stop-line» mark-up by the extra-group vehicles in on-line mode. The authors propose to execute the non-stop movement of coordinated traffic flow with the use of dynamic road signs that recommend the upper limit of speed on the given road section approaching the controlled node of road network. Dynamic monitoring of vehicles and control of their speed by the use of dynamic signs increase the probability of nonstop movement through the nodes of road network by 10–20 %.
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McDuie, Fiona, Michael L. Casazza, David Keiter, Cory T. Overton, Mark P. Herzog, Cliff L. Feldheim, and Joshua T. Ackerman. "Moving at the speed of flight: dabbling duck-movement rates and the relationship with electronic tracking interval." Wildlife Research 46, no. 6 (2019): 533. http://dx.doi.org/10.1071/wr19028.
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Abstract Context Effective wildlife management requires information on habitat and resource needs, which can be estimated with movement information and modelling energetics. One necessary component of avian models is flight speeds at multiple temporal scales. Technology has limited the ability to accurately assess flight speeds, leading to estimates of questionable accuracy, many of which have not been updated in almost a century. Aims We aimed to update flight speeds of ducks, and differentiate between migratory and non-migratory flight speeds, a detail that was unclear in previous estimates. We also analysed the difference in speeds of migratory and non-migratory flights, and quantified how data collected at different temporal intervals affected estimates of flight speed. Methods We tracked six California dabbling duck species with high spatio-temporal resolution GPS–GSM transmitters, calculated speeds of different flight types, and modelled how estimates varied by flight and data interval (30min to 6h). Key results Median migratory speeds were faster (but non-significant) for the larger mallard (Anas platyrhynchos; 82.5kmh–1), northern pintail (Anas acuta; 79.0kmh–1) and gadwall (Mareca strepera; 70.6kmh–1), than the smaller-bodied northern shoveler (Spatula clypeata; 65.7kmh–1), cinnamon teal (Spatula cyanoptera; 63.5kmh–1) and American wigeon (Mareca Americana; 52kmh–1). Migratory flights were faster than non-migratory flights for all species and speeds were consistently slower with an increasing data interval. Implications The need to balance time and energy requirements may drive different speeds for migratory and non-migratory flights. Lower speeds at longer intervals are likely to be due to a greater proportion of ‘loafing’ time included in flighted segments, demonstrating that data acquired at different intervals provide a means to evaluate and estimate behaviours that influence speed estimation. Shorter-interval data should be the most accurate, but longer-interval data may be easier to collect over lengthier timeframes, so it may be expedient to trade-off a degree of accuracy in broad-scale studies for the larger dataset. Our updated flight speeds for dabbling duck species can be used to parameterise and validate energetics models, guide management decisions regarding optimal habitat distribution, and, ultimately, improve conservation management of wetlands for waterfowl.
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Ito, Shinichiro. "Science of Swimming and the Swimming of the Soft Shelled Turtle." MRS Proceedings 1621 (2014): 221–27. http://dx.doi.org/10.1557/opl.2014.3.
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ABSTRACTSwimming is dynamically a part of the hydrodynamic field and can be considered as a field of the optimal control motion. Animals move by instinct according to the situation which they are confronting with. Therefore, their instinctive motion is optimal most of the time. The movement of animals can be classified roughly into two kinds: the fast motion with the maximum speed and the motion with the minimum energy consumption. Considering the foreleg of the soft shelled turtle as a flat plane, several sets of movement of the foreleg were observed and calculated theoretically. The theoretical results agreed the observation results in the both cases with the maximum speed and the minimum energy consumption. Applying the theoretical movement of the soft shelled turtle foreleg to human movement in swimming, the general S-shaped pull stroke is the minimum energy consumption motion in free-style. It became clear that there was a different stroke for generating the maximum speed in free-style. That was the soft shelled turtle style of fast swimming, the I-shaped pull strokes. In 2002 when the author announced this theory, there was only one fast swimmer whose free-style swimming strokes coincidentally accorded with the I-shaped pull with fewer numbers of strokes at that time. He was the Olympic gold medalist Ian Thorp. Now the I-shaped stoke has become main stream in free style.
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Nenajdenko, A. S., V. I. Poddubnyj, and A. I. Valekzhanin. "Modeling the movement control of a wheeled agricultural machine in real time." Traktory i sel hozmashiny 85, no. 3 (June 15, 2018): 32–38. http://dx.doi.org/10.17816/0321-4443-66386.
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The research, which purpose is the development of a motion control system for wheeled agricultural machines, is conducted in Polzunov Altai State Technical University. One of the most important steps in this case is the testing of the developed control algorithms. It is advisable to replace the field trials by real-time motion modeling, which allows to significantly reduce financial and time costs. The developed control algorithm can be conditionally divided into global and local regulation. Global regulation must determine the angle of rotation of the steered wheels (or the angle of the frame break) by a deviation from the specified trajectory, which ensures the motion along the specified trajectory. Input parameters are the specified path of motion, the current coordinates of the machine and the projection of speed on fixed axes. Local control provides the implementation of the set value of the angle of rotation of the steered wheels. To the input of the local adjustment program is given the values of the set and current angles of rotation of the wheels and the direction of rotation of the electric motor of the maneuvering device. The algorithm for determining the required angle of rotation of the wheels is based on the method of predicting the position of the wheeled vehicle through the predetermined forecast time. In real-time tests, the wheeled vehicle is replaced by its mathematical model, obtained using the differential equations of plane motion. The complex of equipment provides registration and generation of the necessary parameters for the operation of the control system in real time. The tests were carried out on the experimental stand «steering - front suspension of the vehicle». The front steerable wheels were rotated by an electromechanical maneuvering device to an angle providing movement along a given trajectory. The motion along rectilinear and curvilinear trajectories was modeled taking into account perturbations from the side of the support surface and without them. When moving along a curvilinear trajectory, the deviation from the specified trajectory does not exceed 0,3 meters at a speed of 3,33 m/s. Based on the results of the experiments, it was established that the implemented control algorithm ensures motion along a given trajectory with a sufficient degree of accuracy.
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Amano, Satoru, Takashi Takebayashi, Keisuke Hanada, Atsushi Umeji, Kohei Marumoto, Keiko Furukawa, and Kazuhisa Domen. "Constraint-Induced Movement Therapy After Injection of Botulinum Toxin Type A for a Patient With Chronic Stroke: One-Year Follow-up Case Report." Physical Therapy 95, no. 7 (July 1, 2015): 1039–45. http://dx.doi.org/10.2522/ptj.20140329.
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Background and Purpose Spasticity, an aspect of upper motor neuron syndrome, is a widespread problem in patients with stroke. To date, no study has reported the long-term (up to 1 year) outcomes of botulinum toxin (BTX) injection in combination with constraint-induced movement therapy in patients with chronic stroke. In this case report, the long-term (1 year) effects of the combination of BTX type A injection and constraint-induced movement therapy on spasticity and arm function in a patient with chronic stroke and arm paresis are described. Case Description The patient was a 66-year-old man who had had an infarction in the right posterior limb of the internal capsule 4 years before the intervention. At screening, the patient was not able to voluntarily extend his interphalangeal or metacarpophalangeal joints beyond the 10 degrees required for constraint-induced movement therapy. From 12 days after BTX type A injection, the patient received 5 hours of constraint-induced movement therapy for 10 weekdays. Outcomes All outcome measures (Modified Ashworth Scale, Fugl-Meyer Assessment, Action Research Arm Test, and amount of use scale of the Motor Activity Log) improved substantially over the 1-year period (before intervention to 1 year after intervention). Repeat BTX type A injections were not necessary because muscle tone and arm function did not worsen during the observation period. Discussion The improved arm function may have reflected improvements in volitional movements and coordination or speed of movements in the paretic arm as a result of a reduction in spasticity, a reduction of learned nonuse behaviors, or use-dependent plasticity after the combination of BTX type A injection and constraint-induced movement therapy. In addition, the possibility of an influence of the passage of time or the Hawthorne effect cannot be ruled out. If this approach proves useful in future controlled studies, it may reduce the rising medical costs of the treatment of stroke.
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Hu, Ning, Shuhua Lin, and Jiayi Cai. "Real-Time Evaluation Algorithm of Human Body Movement in Football Training Robot." Mathematical Problems in Engineering 2021 (May 22, 2021): 1–9. http://dx.doi.org/10.1155/2021/9932737.
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As one of the most challenging topics in the field of artificial intelligence, soccer robots are currently an important platform for humanoid robotics research. Its fields cover a wide range of fields, including robotics, artificial intelligence, and automatic control. Kinematics analysis and action planning are the key technologies in the research of humanoid soccer robots and are the basis for realizing basic actions such as walking. This article mainly introduces the real-time evaluation algorithm of human motion in the football training robot. The football robot action evaluation algorithm proposed here designs the angle and wheel speed of the football robot movement through the evaluation of the angular velocity and linear velocity of the center of mass of the robot. The overall system of the imitation human football robot is studied, including the mechanical system design. The design of the leg structure, the decision-making system based on the finite state machine, the robot vision system, and the image segmentation technology are introduced. The experimental results in this article show that the action of the football training robot model is very stable, the static rotation movement time is about 220 ms, and the fixed-point movement error is less than 1 cm, which fully meets the accuracy requirements of the large-space football robot.
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Hegmann, T. E., J. L. Lin, and J. J. Lin. "Probing the role of nonmuscle tropomyosin isoforms in intracellular granule movement by microinjection of monoclonal antibodies." Journal of Cell Biology 109, no. 3 (September 1, 1989): 1141–52. http://dx.doi.org/10.1083/jcb.109.3.1141.
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Chicken embryo fibroblast (CEF) cells were microinjected with several different monoclonal antibodies that recognize certain nonmuscle isoforms of tropomyosin. Immediately after injection, cells were recorded with a time-lapse video imaging system; later analysis of the tapes revealed that particles in cells injected with one of these antibodies (CG1, specific for CEF tropomyosin isoforms 1 and 3) showed a dramatic decrease in instantaneous speed while moving, distance moved per saltation, and proportion of time spent in motion. Injection of Fab fragments of CG1 resulted in similar changes in the pattern of granule movement. This inhibition of granule movement by CG1 antibody was reversible; at 2.5 h after injection, granules in injected cells had already reached three-fourths of normal speed. The speed of granule movement in cells injected either with antibody specific for tropomyosin isoforms not present in CEF cells, or with CG1 antibody preabsorbed with tropomyosin, was not significantly different from the speed of granules in uninjected cells. When cells were injected with CG1 or Fab fragments of CG1, fixed, and counter-stained with rabbit antibodies to reveal the microtubule, microfilament, and intermediate filament systems, no obvious differences from the patterns normally seen in uninjected cells were observed. Examination of the ultrastructure of injected cells by EM confirmed the presence of apparently intact and normal microtubule, actin, and intermediate filament networks. These experiments suggest that tropomyosin may play an important role in the movement of vesicles and organelles in the cell cytoplasm. Also, we have shown previously that the CG1 determinant can undergo a motility-dependent change in reactivity, that may be important for the regulatory function of nonmuscle tropomyosin (Hegmann, T. E., J. L.-C. Lin, and J. J.-C. Lin. 1988. J. Cell Biol. 106:385-393). Therefore, in addition to postulated microtubule-based motors, microfilaments may play a critical role in regulating granule movement in nonmuscle cells.
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Nour, Majid, Nihat Daldal, Mehmet Fatih Kahraman, Hatem Sindi, Adi Alhudhaif, and Kemal Polat. "A Novel Tilt and Acceleration Measurement System Based on Hall-Effect Sensors Using Neural Networks." Mathematical Problems in Engineering 2022 (January 10, 2022): 1–13. http://dx.doi.org/10.1155/2022/7000486.
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A tilt sensor is a device used to measure the tilt on many axes of a reference point. Tilt sensors measure the bending position according to gravity and are used in many applications. Slope sensors allow easy detection of direction or slope in the air. These tilt gauges have become increasingly popular and are being adapted for a growing number of high-end applications. As an example of practical application, the tilt sensor provides valuable information about an aircraft’s vertical and horizontal tilt. This information also helps the pilot understand how to deal with obstacles during flight. In this paper, Hall-effect effective inclination and acceleration sensor design, which makes a real-time measurement, have been realized. 6 Hall-effect sensors with analog output (UGN-3503) have been used in the sensor structure. These sensors are placed in a machine, and the hall sensor outputs are continuously read according to the movement speed and direction of the sphere magnet placed in the assembly. Hall sensor outputs produce 0–5 Volt analog voltage according to the position of the magnet sphere to the sensor. It is clear that the sphere magnet moves according to the inclination of the mechanism when the mechanism is moved angularly, and the speed of movement from one point to the other changes according to the movement speed. Here, the sphere magnet moves between the hall sensors in the setup according to the ambient inclination and motion acceleration. Each sensor produces analog output values in the range of 0–5 V instantaneous according to the position of the spheroid. Generally defined, according to the sphere magnet position and movement speed, the data received from the hall sensors by the microcontroller have been sent to the computer or microcomputer unit as UART. In the next stage, the actual sensor has been removed. The angle and acceleration values have been continuously produced according to the mechanism’s movement and output as UART. Thanks to the fact that the magnet is not left idle and is fixed with springs, problems such as vibration noises and wrong movements and the magnet leaning to the very edge and being out of position even at a slight inclination are prevented. In addition, the Hall-effect sensor outputs are given to an artificial neural network (ANN), and the slope and acceleration information is estimated in the ANN by training with the data obtained from the real-time slope and accelerometer sensor.
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Zhu, Tongyu, Zhixin Song, Dongdong Wu, and Jianjun Yu. "A Novel Freeway Traffic Speed Estimation Model with Massive Cellular Signaling Data." International Journal of Web Services Research 13, no. 1 (January 2016): 69–87. http://dx.doi.org/10.4018/ijwsr.2016010105.
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With the growing popularity of cell phones, using massive cellular signaling data as probe to track the vehicles movement trajectory and obtain the real-time traffic condition has become one of the most attractive candidate techniques. However, traditional approaches may offer a poor performance in removing noisy data and minimizing deviation of traffic speed in adjacent time intervals. In this paper, a novel approach is proposed to solve these two issues. The authors move noisy data by comparing the cellular signaling data with the trained data set, and adopt a modified Kalman filter algorithm to minimize the deviations. The experiment results show that the accuracy of the approach performs better in comparison to other two traffic speed estimation approaches.
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Gulde, Philipp, Joachim Hermsdörfer, and Peter Rieckmann. "Speed but Not Smoothness of Gait Reacts to Rehabilitation in Multiple Sclerosis." Multiple Sclerosis International 2021 (June 3, 2021): 1–8. http://dx.doi.org/10.1155/2021/5589562.
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Introduction. Improved gait is one of the leading therapy goals in multiple sclerosis. A plethora of clinical timed trials and state-of-the-art technology-based approaches are available to assess gait performance. Objectives. To examine what aspects of gait react to inpatient rehabilitation in MS and which parameters should be best assessed. Design. In this longitudinal study, we examined the performance of 76 patients with MS to shed further light on factors influencing gait, associations between tests, and the reaction to inpatient rehabilitation during an average time span of 16 d. Setting. Private specialist clinic for inpatient neurorehabilitation. Main Outcome Measures. Clinical walk tests (timed 25-foot walk test at normal pace, maximum pace over 10 m or 6 min) and IMU-based measures of movement smoothness. Results. All gait parameters were strongly intercorrelated (all p < 0.05 ), and a model multiple linear regression for the 6MWT revealed short distance velocity (10 m) and movement smoothness as predictors in a strong model ( R 2 adjusted 0.75, p < 0.01 ). A second model with natural pace on short distance and movement smoothness was almost equally strong ( R 2 adjusted 0.71, p < 0.01 ). Patients improved their walking speed ( p < 0.01 ), but not smoothness ( p = 0.08 – 0.12 ), over the course of rehabilitation. Conclusions. Since we were not able to observe improvements in smoothness of gait, we conclude that rehabilitation programs should be adapted to the patient’s physiological capacities in order to allow for such improvements in smoothness of gait. Externally valid gait capacity (6MWT) could be predicted by a single walk for 10 s at natural pace.
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Dupuis, Frédérique, Gisela Sole, Catherine Mercier, and Jean-Sébastien Roy. "Impact of fatigue at the shoulder on the contralateral upper limb kinematics and performance." PLOS ONE 17, no. 4 (April 1, 2022): e0266370. http://dx.doi.org/10.1371/journal.pone.0266370.
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Background Altered movement patterns have been proposed as an etiological factor for the development of musculoskeletal pain. Fatigue influences upper limb kinematics and movement performance which could extend to the contralateral limb and potentially increasing risk of injury. The aim of this study was to investigate the impact of fatigue at the dominant arm on the contralateral upper limb movement. Methods Forty participants were randomly assigned to one of two groups: Control or Fatigue Group. All participants completed a reaching task at the baseline and post-experimental phase, during which they reached four targets with their non-dominant arm in a virtual reality environment. Following the baseline phase, the Fatigue Group completed a shoulder fatigue protocol with their dominant arm only, while the Control Group took a 10-minute break. Thereafter, the reaching task was repeated. Upper limb and trunk kinematics (joint angles and excursions), spatiotemporal (speed and accuracy) and surface electromyographic (sEMG) activity (sEMG signal mean epoch amplitude and median frequency of the EMG power spectrum) were collected. Two-way repeated-measures ANOVA were performed to determine the effects of Time, Group and of the interaction between these factors. Results There was a significant Time x Group interaction for sternoclavicular elevation range of motion (p = 0.040), movement speed (p = 0.043) and accuracy (p = 0.033). The Fatigue group showed higher contralateral sternoclavicular elevation and increased movement error while experiencing fatigue in the dominant arm. Moreover, the Control group increased their speed during the Post-experimental phase compared to baseline (p = 0.043), while the Fatigue group did not show any speed improvement. There was no EMG sign of fatigue in any of the muscles evaluated. Conclusion This study showed that fatigue at the dominant shoulder impacts movement at the contralateral upper limb. Such changes may be a risk factor for the development of shoulder pain in both the fatigued and non-fatigued limbs.
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Ding, You Qing. "The Comparison Study on the Performance of Centrifugal Atomizer." Advanced Materials Research 726-731 (August 2013): 1968–71. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1968.
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High speed rotating centrifugal atomizer is the key equipment for the flue gas processing. The centrifugal high-speed atomizer is running at high speed, it makes micron liquid-drop in order that chemical reaction happened between micron drop and harmful gas. Its function has direct impact to the emission produced from WTE(waste to energy) plant. The different driving form affects the atomizers stability of high speed movement, atomization effect and the running life directly. For a long time, the transmission quality of belt drive or direct coupling drive is one of the focus issues. Based on the high speed centrifugal atomizer, this paper introduces the two commonly used driving forms of the atomizer, and compares their performance through the experiments. Key words: atomizer, WTE, experiment