Research Article
Cardinal Basis Piecewise Hermite Interpolation on Fuzzy Data
H. Vosoughi and S. Abbasbandy
Department of Mathematics, Islamic Azad University, Science and Research Branch, Tehran, Iran
Correspondence should be addressed to S. Abbasbandy; abbasbandy@yahoo.com
Received 6 June 2016; Accepted 7 December 2016
Academic Editor: Katsuhiro Honda
Copyright © 2016 H. Vosoughi and S. Abbasbandy. Tis is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
A numerical method along with explicit construction to interpolation of fuzzy data through the extension principle results by widely
used fuzzy-valued piecewise Hermite polynomial in general case based on the cardinal basis functions, which satisfy a vanishing
property on the successive intervals, has been introduced here. We have provided a numerical method in full detail using the linear
space notions for calculating the presented method. In order to illustrate the method in computational examples, we take recourse
to three prime cases: linear, cubic, and quintic.
1. Introduction
Fuzzy interpolation problem was posed by Zadeh [1]. Lowen
presented a solution to this problem, based on the fundamen-
tal polynomial interpolation theorem of Lagrange (see, e.g.,
[2]). Computational and numerical methods for calculating
the fuzzy Lagrange interpolate were proposed by Kaleva
[3]. He introduced an interpolating fuzzy spline of order .
Important special cases were =2, the piecewise linear
interpolant, and =4, a fuzzy cubic spline. Moreover, Kaleva
obtained an interpolating fuzzy cubic spline with the not-
a-knot condition. Interpolating of fuzzy data was developed
to simple Hermite or osculatory interpolation, (3) cubic
splines, fuzzy splines, complete splines, and natural splines,
respectively, in [4–8] by Abbasbandy et al. Later, Lodwick and
Santos presented the Lagrange fuzzy interpolating function
that loses smoothness at the knots at every -cut; also every
-cut ( ̸ = 1) of fuzzy spline with the not--knot boundary
conditions of order has discontinuous frst derivatives
on the knots and based on these interpolants some fuzzy
surfaces were constructed [9]. Zeinali et al. [10] presented
a method of interpolation of fuzzy data by Hermite and
piecewise cubic Hermite that was simpler and consistent
and also inherited smoothness properties of the generator
interpolation. However, probably due to the switching points
difculties, the method was expressed in a very special
case and none of three remaining important cases was not
investigated and this is a fundamental reason for the method
weakness.
In total, low order versions of piecewise Hermite inter-
polation are widely used and when we take more knots,
the error breaks down uniformly to zero. Using piecewise-
polynomial interpolants instead of high order polynomial
interpolants on the same material and spaced knots is a
useful way to diminish the wiggling and to improve the
interpolation. Tese facts, as well as cardinal basis functions
perspective, motivated us in [11] to patch cubic Hermite
polynomials together to construct piecewise cubic fuzzy
Hermite polynomial and provide an explicit formula in a
succinct algorithm to calculate the fuzzy interpolant in cubic
case as a new replacement method for [4, 10].
Now, in this paper, in light of our previous work, we
want to introduce a wide general class of fuzzy-valued
interpolation polynomials by extending the same approach
in [11] applying a very special case of which general class of
fuzzy polynomials could be an alternative to fuzzy osculatory
interpolation in [4] and so its lowest order case ( =
1), namely, the piecewise linear polynomial, is an analogy
of fuzzy linear spline in [3]. Meanwhile, when =2
with exactly the same data, we will simply produce the
second lower order form of mentioned general class that was
introduced in [11] and the interpolation of fuzzy data in [10].
Te paper is organized in fve sections. In Section 2, we
have reviewed defnitions and preliminary results of several
Hindawi Publishing Corporation
Advances in Fuzzy Systems
Volume 2016, Article ID 8127215, 8 pages
http://dx.doi.org/10.1155/2016/8127215