The accuracy of estimating time to contact in transversal motion and head-on motion

The ability to estimate precisely the time to contact (TTC) of the objects is necessary for planning actions in dynamic environments. TTC estimation is involved in many everyday activities with different levels of difficulty. Although tracking a ball that moves at a constant speed and estimating the time it reaches a non-moving target can be fairly simple, tracking a fast moving car with inconsistent speeds and estimating the time it reaches another car is rather difficult. In this study, we asked participants to estimate TTC of an object in transversal and head-on motions. The object became invisible shortly after movement initiation. The results demonstrated that TTC estimation for transversal motion is more accurate than for head-on motion. We present a mathematical model to explain why humans are better in estimating TTC for transversal motion than for head-on motion.

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Estimation of time to contact in lateral motion and approach motion

10.1101/408310 ◽

2018 ◽

Author(s):

Asieh Daneshi

Keyword(s):

Mathematical Analysis ◽

Human Subjects ◽

Dynamic Environments ◽

Lateral Motion ◽

Movement Initiation ◽

Time To Contact ◽

Estimation Of Time

The ability to estimate precisely the time to contact (TTC) of the objects is necessary for planning actions in dynamic environments. However, this ability is not the same for all kinds of movement. Sometimes tracking an object and estimating its TTC is easy and accurate and sometimes it is not. In this study, we asked human subjects to estimate TTC of an object in lateral motion and approach motion. The object became invisible shortly after movement initiation. The results proved that TTC estimation for lateral motion is more accurate than for approach motion. We used mathematical analysis to show why humans are better in estimating TTC for lateral motion than for approach motion.

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A model to account for the consequences of host nutrition on the outcome of gastrointestinal parasitism in sheep: model evaluation

Parasitology ◽

10.1017/s0031182007002624 ◽

2007 ◽

Vol 134 (9) ◽

pp. 1279-1289 ◽

Cited By ~ 13

Author(s):

D. VAGENAS ◽

S. C. BISHOP ◽

I. KYRIAZAKIS

Keyword(s):

Mathematical Model ◽

Worm Burden ◽

Management Strategies ◽

Sensitivity Analyses ◽

Sheep Model ◽

Host Nutrition ◽

Gastrointestinal Parasitism ◽

Different Characteristics ◽

Nutritional Strategies ◽

Different Levels

SUMMARYThis paper describes sensitivity analyses and expectations obtained from a mathematical model developed to account for the effects of host nutrition on the consequences of gastrointestinal parasitism in sheep. The scenarios explored included different levels of parasitic challenge at different planes of nutrition, for hosts differing only in their characteristics for growth. The model was able to predict the consequences of host nutrition on the outcome of parasitism, in terms of worm burden, number of eggs excreted per gram faeces and animal performance. The model outputs predict that conclusions on the ability of hosts of different characteristics for growth to cope with parasitism (i.e. resistance) depend on the plane of nutrition. Furthermore, differences in the growth rate of sheep, on their own, are not sufficient to account for differences in the observed resistance of animals. The model forms the basis for evaluating the consequences of differing management strategies and environments, such as breeding for certain traits associated with resistance and nutritional strategies, on the consequences of gastrointestinal parasitism on sheep.

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Step-by-step control of target efficiency indices of the control and measuring equipment stock applied in construction and housing and communal services

MATEC Web of Conferences ◽

10.1051/matecconf/201817001010 ◽

2018 ◽

Vol 170 ◽

pp. 01010 ◽

Cited By ~ 2

Author(s):

Rustam Khayrullin ◽

Pavel Ivanov

Keyword(s):

Mathematical Model ◽

Finite Difference ◽

Measuring Equipment ◽

Technical Condition ◽

Measuring Instruments ◽

Finite Difference Equations ◽

Target Values ◽

The Mathematical Model ◽

Step Control ◽

Different Levels

The mathematical model is considered for the formation and implementation of development strategies of the stock of control and measuring instruments (CMI) applied in construction and housing and communal services(HCS), and step-by-step control of efficiency target values of the stock. The model is based on a system of finite - difference equations describing the change of number of the CMI samples with different levels of technical perfection and technical condition at each planning interval. The model allows calculating the required number of CMI for procurement and repairs in the various groups for provide target values of efficiency indices at each planning interval. Controller is number of modern CMI samples for procurement and number of modern and obsolete faulty CMI samples for the repairs. The results of calculations are presented.

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An Improved Trace Method for Moving Target under Occlusion

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.672-674.1931 ◽

2014 ◽

Vol 672-674 ◽

pp. 1931-1934

Author(s):

Yu Bing Dong ◽

Guang Liang Cheng ◽

Ming Jing Li

Keyword(s):

Mathematical Model ◽

Target Tracking ◽

Difficult Problem ◽

Block Matching ◽

Experimental Results ◽

Polar Coordinates ◽

Moving Target ◽

Trajectory Prediction ◽

Tracking Method

Occlusion is a difficult problem to be solved in the process of target tracking. In order to solve the problem of occlusion, a new tracking method combined with trajectory prediction and multi-block matching is presented and studied,and a mathematical model of trajectory prediction of moving target is established in polar coordinates and verified through some experiments. The experimental results show that the new tracking method can be better to trace and forecast the moving target under occlusion.

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Eye-hand coordination during flexible manual interception of an abruptly appearing, moving target

Journal of Neurophysiology ◽

10.1152/jn.00476.2017 ◽

2018 ◽

Vol 119 (1) ◽

pp. 221-234 ◽

Cited By ~ 6

Author(s):

Yuhui Li ◽

Yong Wang ◽

He Cui

Keyword(s):

Eye Movements ◽

Moving Objects ◽

Reaction Times ◽

Hand Movements ◽

Moving Target ◽

Target Displacement ◽

Transmission Delays ◽

Sensory Transmission ◽

Hand Coordination ◽

Different Levels

As a vital skill in an evolving world, interception of moving objects relies on accurate prediction of target motion. In natural circumstances, active gaze shifts often accompany hand movements when exploring targets of interest, but how eye and hand movements are coordinated during manual interception and their dependence on visual prediction remain unclear. Here, we trained gaze-unrestrained monkeys to manually intercept targets appearing at random locations and circularly moving with random speeds. We found that well-trained animals were able to intercept the targets with adequate compensation for both sensory transmission and motor delays. Before interception, the animals' gaze followed the targets with adequate compensation for the sensory delay, but not for extra target displacement during the eye movements. Both hand and eye movements were modulated by target kinematics, and their reaction times were correlated. Moreover, retinal errors and reaching errors were correlated across different stages of reach execution. Our results reveal eye-hand coordination during manual interception, yet the eye and hand movements may show different levels of prediction based on the task context. NEW & NOTEWORTHY Here we studied the eye-hand coordination of monkeys during flexible manual interception of a moving target. Eye movements were untrained and not explicitly associated with reward. We found that the initial saccades toward the moving target adequately compensated for sensory transmission delays, but not for extra target displacement, whereas the reaching arm movements fully compensated for sensorimotor delays, suggesting that the mode of eye-hand coordination strongly depends on behavioral context.

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Constant Speed Motion Simulation and Error Analysis of Planar Non-Circular Curve Parts

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.220-223.1559 ◽

2012 ◽

Vol 220-223 ◽

pp. 1559-1563

Author(s):

Rui Wu ◽

Li Bao ◽

Yuan Kui Xu

Keyword(s):

Mathematical Model ◽

Error Analysis ◽

Relative Error ◽

Plane Curve ◽

Simulation System ◽

Constant Speed ◽

Motion Simulation ◽

Production Practice ◽

The Mathematical Model ◽

Circular Curve

The relative direction for a constant speed can be determined according to the planar non-circular curve parts. To establish the mathematical model, a constant speed motion simulation system is designed. The parameters of (vH=5mm/s, δ<3") is commonly used for the simulation system to simulate the movement of drawing the error curve. The results show that by controlling the movement of the plane curve parts in mathematical model can derive the basic constant speed, the relative error of constant speed is less than 3%, it provides a reliable bias when apply to production practice.

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