Search results for "Polynomial curve"
showing 4 items of 4 documents
Using Genetic Algorithms for Optimizing the PPC in the Highway Horizontal Alignment Design.
2016
Various studies have emphasized the interesting advantages related to the use of new transition curves for improving the geometric design of highway horizontal alignments. In a previous paper, one of the writers proposed a polynomial curve, called a polynomial parametric curve (PPC), proving its efficiency in solving several design problems characterized by a very complex geometry (egg-shaped transition, transition between reversing circular curves, semidirect and inner-loop connections, and so on). The PPC also showed considerable advantages from a dynamic perspective, as evidenced by the analysis of the main dynamic variables related to motion (as well as rate of change of radial accelera…
An algorithm based on the PPC (Polynomial Parametric Curve) for designing horizontal highway alignments
2015
Criteria for geometric design of highway alignments have been studied in various researches so far, providing new methods, as alternative to traditional approaches. They can be useful for obtaining better solutions, characterized by high performances in terms of motion safety and comfort. In particular, continuous curvature alignments, based on polynomial functions, are highly consistent solutions with users' driving behaviour and vehicle trajectories. Moreover, alignment geometry optimization allows engineers to minimize dynamic effects on drivers with considerable advantages in terms of comfort and safety. This paper carries on the research of a previous study, in which a polynomial param…
The Relationship Between Tooth Size Discrepancy and Archform Classification in Orthodontic Patients
2015
Background: To determine the relationship between clinically significant tooth size discrepancies (TSD) and archform classification in orthodontic patients. Material and Methods: Two hundred and forty consecutive sets of pre-treatment orthodontic study models were scanned and landmarked. All models had permanent teeth erupted from first molar to first molar in both arches. Sixty sets of images were classified into two groups of 30 according to the presence (group 1) or absence (group 2) of a clinically significant overall or anterior TSD (>2 SD from Bolton’s original means). Mean upper and lower archforms were created for each group using a fourth degree polynomial curve. Upper and lower ar…
Uniform estimates for the X-ray transform restricted to polynomial curves
2012
We establish near-optimal mixed-norm estimates for the X-ray transform restricted to polynomial curves with a weight that is a power of the affine arclength. The bounds that we establish depend only on the spatial dimension and the degree of the polynomial. Some of our results are new even in the well-curved case.