Results 31 to 40 of about 82,785 (291)
On the unfolding of simple closed curves [PDF]
Transactions of the American Mathematical Society, 2008 We show that every rectifiable simple closed curve in the plane can be continuously deformed into a convex curve in a motion which preserves arc length and does not decrease the Euclidean distance between any pair of points on the curve. This result is obtained by approximating the curve with polygons and invoking the result of Connelly, Demaine, and ...
openaire +3 more sources
An equality for the curvature function of a simple and closed curve on the plane
International Journal of Mathematics and Mathematical Sciences, 2003 We prove an equality for the curvature function of a simple and closed curve on the plane. This equality leads to another proof of the four-vertex theorem in differential geometry.
Biao Ou
doaj +1 more source
Numerical Simulation of Gas Explosion in Confined Space
Meikuang Anquan, 2020 According to the problem of gas explosion characteristics in mine closed fire zone, FLACS software is used to establish a simple closed space to simulate pressure changes, temperature changes and flame development during gas explosion.
LUO Zhenmin, WU Gang
doaj +1 more source
Fractional-Order Approximation of PID Controller for Buck–Boost Converters
Micromachines, 2021 Viability of a fractional-order proportional–integral–derivative (PID) approximation to regulate voltage in buck–boost converters is investigated. The converter applications range not only to high-power ones but also in micro/nano-scale systems from ...
Allan G. S. Sánchez +3 more
doaj +1 more source
Forum of Mathematics, Sigma, 2021 Many natural real-valued functions of closed curves are known to extend continuously to the larger space of geodesic currents. For instance, the extension of length with respect to a fixed hyperbolic metric was a motivating example for the development of
Dídac Martínez-Granado +1 more
doaj +1 more source
Computing shortest closed curves on non-orientable surfaces
Journal of Computational GeometryWe initiate the study of computing shortest non-separating simple closed curves with some given topological properties on non-orientable surfaces.
Denys Bulavka +2 more
doaj +1 more source
Clinics and Practice, 2013 Recently, three-dimensional (3D) closed curve trajectories of markers placed at strategic body locations, called cyclograms or Lissajous-like graphs, are used for treadmill gait analysis.
Shigeo Tanabe +5 more
doaj +1 more source
International Journal of Mathematics and Mathematical Sciences, 1985 Let C be a simple closed convex curve in the plane for which the radius of curvature ρ is a continuous function of the arc length. Such a curve is called a convex curve of bounded type, if ρ lies between two fixed positive bounds.
A. W. Goodman
doaj +1 more source
Simple quantum systems in spacetimes with closed timelike curves [PDF]
Physical Review D, 1992 Three simple examples illustrate properties of path integral amplitudes in fixed background spacetimes with closed timelike curves: non-relativistic potential scattering in the Born approximation is non-unitary, but both an example with hard spheres and the exact solution of a totally discrete model are unitary.
openaire +4 more sources
Ibn Al-Haitham Journal for Pure and Applied Sciences, 2018 Jordan curve theorem is one of the classical theorems of mathematics, it states the following : If is a graph of a simple closed curve in the complex plane the complement of is the union of two regions, being the common ...
Narjis A. Dawood, Suaad G. Gasim
doaj +1 more source