concave function

(redirected from Concave-down)

concave function

[′kän‚kāv ′fəŋk·shən]
(mathematics)
A function f (x) is said to be concave over the interval a,b if for any three points x1, x2, x3 such that a <>x1<>x2<>x3<>b, f (x2)≥ L (x2), where L (x) is the equation of the straight line passing through the points [x1, f (x1)] and [x3, f (x3)].
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At present, some limitations exist to modeling the ROS of subjects with hemiplegia as the lower arc of a circle since some of the data from hemiplegic subjects cannot be adequately represented by this model (e.g., some of the ROS are concave-down or are flat).
However, at present some limitations exist to applying the ROS analyses to data from subjects with hemiplegia: our ability to compute meaningful radii and arc lengths is compromised for flat shapes and concave-down shapes (leading to the exclusion of three subjects from this study).
In addition, it is obviously observed that [DELTA]Y > 0 for Re = 10 and [DELTA]Y < 0 for Re = 100, which represents the concave-down and concave-up pattern, respectively.
This indicates that the concave-down pattern as well as the concave-up pattern can be observed in the simulations.