Regarding the importance of ring spinning method among spinning systems, great potentials exist for research about on the improvement of the quality and properties of ring spun yarn. This study aims to improve yarn quality by changing the shape and dimensions of spinning triangle through forming a groove in the middle zone of the front darfting &#10roller with a curvature of 5 to 7 mm. For the ...

In order to obtain a global principle for modeling closed surfaces of arbitrary genus, rst hyperbolic geometry and then discrete groups of motions in planar geometries of constant curvature are studied. The representation of a closed surface as an orbifold leads to a natural parametrization of the surfaces as a subset of one of the classical geome-tries S 2 , E 2 and H 2. This well known connec...

-Line segments are ordinary in industrial scene, accurate line segments matching is a key step for many applications, such as 3-D reconstruction. A matching method based on epipolar-line constraint and line segment features is proposed. Firstly, the points on line segments between image pairs are matched by epipolar-line constraint. Secondly, geometric descriptor and gray value descriptor are u...

A faithful (unit) distance graph in Rd is a graph whose set of vertices is a finite subset of the d-dimensional Euclidean space, where two vertices are adjacent if and only if the Euclidean distance between them is exactly 1. A (unit) distance graph in Rd is any subgraph of such a graph. In the first part of the paper we focus on the differences between these two classes of graphs. In particula...

We prove that, building upon the universal-existential orthogonality-based axiom system for metric planes presented in [28], one can provide universal-existential axiom systems – expressed solely in terms of the ternary predicate I, with I(abc) standing for ‘ab is congruent to ac’, which Pieri has introduced 100 years ago – for metric planes, for absolute geometry with the circle axiom, for Euc...

We consider the simplicial state-sum model of Ponzano and Regge as a path integral for quantum gravity in three dimensions. We examine the Lorentzian geometry of a single 3-simplex and of a simplicial manifold, and interpret an asymptotic formula for 6j-symbols in terms of this geometry. This extends Ponzano and Regge’s similar interpretation for Euclidean geometry. We give a geometric interpre...

We determine the implicit assumptions and the structure of the Single and Double Cross Calculi within Euclidean geometry, and use these results to guide the construction of analogous calculi in mereogeometry. The systems thus obtained have strong semantic and deductive similarities with the Euclidean-based Cross Calculi although they rely on a different geometry. This fact suggests that putting...

We present a deterministic local routing scheme that is guaranteed to find a path between any pair of vertices in a halfθ6-graph whose length is at most 5/ √ 3 = 2.886... times the Euclidean distance between the pair of vertices. The half-θ6graph is identical to the Delaunay triangulation where the empty region is an equilateral triangle. Moreover, we show that no local routing scheme can achie...

A geometric t-spanner on a set of points in Euclidean space is a graph containing for every pair of points a path of length at most t times the Euclidean distance between the points. Informally, a spanner is O(k)-robust if deleting k vertices only harms O(k) other vertices. We show that on any one-dimensional set of n points, for any ε > 0, there exists an O(k)-robust 1-spanner with O(n1+ε) edg...

TOPSIS is a multicriteria decision making technique based on the minimization of geometric distances that allows the ordering of compared alternatives in accordance with their distances from the ideal and anti-ideal solutions. The technique, that usually measures distances in the Euclidean norm, implicitly supposes that the contemplated attributes are independent. However, as this rarely occurs...