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2014, Applied Mathematical Sciences
An efficient numerical technique has been formulated for determining the length of curves with accuracy of order Οሺ10 ିଵ ሻ. The technique is based on the Cauchy integral formula and makes use of an iterative approach for finding out the derivatives of the generating function at the nodes of the Gauss-Legendre n-point rule inside the range of integration. The method has been verified by considering some standard examples.
IEEE Transactions on Pattern Analysis and Machine Intelligence, 2004
This paper compares previously published length estimators in image analysis having digitized curves as input. The evaluation uses multigrid convergence (theoretical results and measured speed of convergence) and further measures as criteria. This paper also suggests a new gradient-based method for length estimation, and combines a previously proposed length estimator for straight segments with a polygonalization method.
Journal of graphics tools, 2002
This paper describes a simple technique for evaluating the length of a parametric curve. The technique approximates sections of the curve to the arc of a circle using only sample points on the curve: no computation of derivatives or other properties is required. This method is almost as quick to implement and compute as chord-length summation but is much more accurate : it also provides recursion criteria for adaptive sampling. At the end of paper, we discuss briefly the way the algorithm extends to estimate the area of a parametric surface.
From few simple and relatively well-known mathematical tools, an easily understandable, though powerful, method has been devised that gives many useful results about numerical functions. With mere Taylor expansions, Dirac delta functions and Fourier transform with its discrete counterpart, the DFT, we can obtain, from a digitized function, its integral between any limits, its Fourier transform without band limitations and its derivatives of any order. The same method intrinsically produces polynomial splines of any order and automatically generates the best possible end conditions. For a given digitized function, procedures to determine the optimum parameters of the method are presented. The way the method is structured makes it easy to estimate fairly accurately the error for any result obtained. Tests conducted on nontrivial numerical functions show that relative as well as absolute errors can be much smaller than f 3ff , and there is no indication that even better results could not be obtained. The method works with real or complex functions as well; hence, it can be used for inverse Fourier transforms too. Implementing the method is an easy task, particularly if one uses symbolic mathematical software to establish the formulas. Once formulas are worked out, they can be efficiently implemented in a fast compiled program. The method is relatively fast; comparisons between computation time for fast Fourier transform and Fourier transform computed at different orders are presented. Accuracy increases exponentially while computation time increases quadratically with the order. So, as long as one can afford it, the trade-off is beneficial. As an example, for the fifth order, computation time is only ten times greater than that of the FFT while accuracy is f H times better. Comparisons with other methods are presented. PACS Nos.: 02.00 and 02.60
Canadian Journal of Physics, 1998
From few simple and relatively well-known mathematical tools, an easily understandable, though powerful, method has been devised that gives many useful results about numerical functions. With mere Taylor expansions, Dirac delta functions and Fourier transform with its discrete counterpart, the DFT, we can obtain, from a digitized function, its integral between any limits, its Fourier transform without band limitations and its derivatives of any order. The same method intrinsically produces polynomial splines of any order and automatically generates the best possible end conditions. For a given digitized function, procedures to determine the optimum parameters of the method are presented. The way the method is structured makes it easy to estimate fairly accurately the error for any result obtained. Tests conducted on nontrivial numerical functions show that relative as well as absolute errors can be much smaller than 10-100, and there is no indication that even better results could n...
SIAM Journal on Numerical Analysis, 1993
In this paper, some simple methods for the calculation of line integrals over smooth curves are considered, where an explicitly differential parametrization for the curve is either not available or is inconvenient to differentiate explicitly. The method consists in first replacing a parametrization of the curve by a piecewise polynomial interpolant of it, and then using a Newton-Cotes formula for the integration of the resulting integral. The surprising result is that the order of convergence of the resulting quadrature is higher than would be expected on the basis of interpolation theory alone. Indeed, an interpolation polynomial of order p (degree p), reproduces the derivatives of the parametrization function, needed for line integrals, only up to order p-1. But on using on each subinterval an interpolation formula of order p coupled with a Newton-Cotes quadrature rule using p nodes, the resulting integration method has the same order as would be obtained by applying only the Newton-Cotes formula with the original parametrization of the curve.
19th Congress of the International Commission for Optics: Optics for the Quality of Life, 2003
4.4 Procedure for tracing curves in parametric form x = f(t) and y = (t) 4.5 Procedure for tracing Polar curves 4.6 Areas of Cartesian curves 4.7 Areas of Polar curves 4.8 Lengths of curves 4.9 Volumes of Revolution by Double Integrals 4.10 Volumes of Revolution by Triple Integrals 4.11 Volumes of solids
Journal of Computational and Applied Mathematics, 1997
Although the predictor-corrector curve tracing method has found a wide variety of significant applications, the calculation of line integrals over implicitly defined curves seems to have been overlooked. In this paper, we present two modified numerical integration techniques, namely, the modified trapezoidal and the modified Romberg rules and results of some numerical experiments for evaluating the line integral of a vector field over an implicitly defined curve. Moreover, we give a proof of an asymptotic error expansion for a modified trapezoidal rule which is a modification of that of Verlinden and Cools .
SpringerPlus, 2016
In the last two decades, have constructed a direct cubic spline that fits the first derivatives at the knots together with the value of the function and its second derivative at the beginning of the interval. They used it for the solution quadrature formula. El Tarazi and have constructed five types of even degree splines ( j = 2k, k = 1, 2, 3, 4, 5) that match the derivatives up to the order k at the knots of a uniform partition for each k = 1, 2, 3, 4, and 5. These splines are also applied to quadrature. Recently, Rathod et al. ( ) presented a formulation and study of an interpolatory cubic spline (named Subbotin cubic spline) to compute the integration over curved domains in the Cartesian two space and the integral approximations (quadrature). In this work, we construct a twelfth degree spline which interpolates the derivatives up to the order 6 of a given function at the knots and its value at the beginning of the interval. We obtain a direct simple formula for the proposed spline. Error bounds for the function is derived in the sense of the Hermite interpolation. Also, a mistakes in the literature was corrected. Finally, numerical examples and comparison with other available methods are presented to illustrate the usefullness of proposed method. We construct here a class of interpolating splines of degree 12. Error estimates for this spline is also represented.
Computer-Aided Design, 2011
We use the canonical equations (CE) of differential geometry, a local Taylor series representation of any smooth curve with parameter the arc length, as a unifying framework for the development of new CNC algorithms, capable of interpolating 2D and 3D curves, represented parametrically, implicitly or as surface intersections, with accurate feedrate control. We use a truncated form of the CE to compute a preliminary point, at an arc distance from the last interpolation point selected to achieve a desired feedrate profile. The next interpolation point is derived by projecting the preliminary point on the curve. The coefficients in the CE involve the curve's curvature, torsion and their arc length derivatives. We provide computing procedures for them for common Cartesian representations, demonstrating the generality of the proposed method. In addition, our algorithms admit corrections, which render them more accurate in terms of the programmed feedrate, compared to existing parametric algorithms of the same order.
Geometric modeling: Theory and practice, 1997
We present new methods to approximate the offset and convolution of planar curves. These methods can be used as fundamental tools in various geometric applications such as NC machining and collision detection of planar curved objects. Using quadratic curve approximation and tangent field matching, the offset and convolution curves can be approximated by polynomial or rational curves within the tolerance of approximation error > 0. We suggest three methods of offset approximation, all of which allow simple error analysis and at the same time provide high-precision approximation. Two methods of convolution approximation are also suggested that approximate convolution curves with polynomial or rational curves.
Computational Methods for Algebraic Spline Surfaces, 2005
This paper examines recursive Taylor methods for multivariate polynomial evaluation over an interval, in the context of algebraic curve and surface plotting as a particular application representative of similar problems in CAGD. The modified affine arithmetic method (MAA), previously shown to be one of the best methods for polynomial evaluation over an interval, is used as a benchmark; experimental results show that a second order recursive Taylor method (i) achieves the same or better graphical quality compared to MAA when used for ...
The horizontal circular curve can be described by seven elements: (1) Radius of the curve; (2)deflection angle between tangents; (3) tangent distance; (4) external distance; (5) middle ordinate; (6) long chord; and (7) length of the curve. When the radius and deflection angle are given, the other five curve elements can be directly computed. In some practical problems, the radius and the deflection angle are unknown; two other elements must be known to solve the problem. Seven cases must be solved depending on the known curve elements, as mentioned by other authors. This paper present three other cases and a direct method is proposed for two cases of the earlier seven.
We report here a new possible two formulas for obtaining the length of irregular arc ℓ in terms of their base b and height h. The first formula is obtained by applying the law of cosines and intersecting chord theory and ℓ is given by . While the other is obtained by applying Pythagorean theory and ℓ is given by with an error of , where K is a constant and equal 0.313165528 and can be used only in case of 2h < b. Finally, the earth circumference is calculated by using the two formulas and their values are 39910.0252 Km and 39999.5504 Km, which is consistent with the reported elsewhere (39992.1984 km).
2019
Newton-Lagrange Interpolations are widely used in<br> numerical analysis. However, it requires a quadratic computational<br> time for their constructions. In computer aided geometric design<br> (CAGD), there are some polynomial curves: Wang-Ball, DP and<br> Dejdumrong curves, which have linear time complexity algorithms.<br> Thus, the computational time for Newton-Lagrange Interpolations<br> can be reduced by applying the algorithms of Wang-Ball, DP and<br> Dejdumrong curves. In order to use Wang-Ball, DP and Dejdumrong<br> algorithms, first, it is necessary to convert Newton-Lagrange<br> polynomials into Wang-Ball, DP or Dejdumrong polynomials. In<br> this work, the algorithms for converting from both uniform and<br> non-uniform Newton-Lagrange polynomials into Wang-Ball, DP and<br> Dejdumrong polynomials are investigated. Thus, the computational<br> time for representing Newton-Lagrange polynomials can b...
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 1994
This paper describes numerical integration algorithms based upon Bezier splines. Numerical integration in the context of circuit simulation takes place in the transient analysis portion of the circuit simulators. The solution to the differential-algebraic equation system describing a dynamic circuit is obtained by formulas which formulate the solution as a Bezier function. The algorithms presented in this paper are fully
The application of modern surveying techniques has greatly reduced the rigours associated with engineering surveys. The known properties of curves have also been incorporated in these techniques in the setting out operations and accuracy is usually enhanced by applying arc-to-chord correction. It has however been difficult to differentiate between the errors due to field operation and that due to curve ranging technique employed. A new and unique property of circular curves known as Curve Constant (CC) has been developed in this work. The CC is employed to facilitate planning in curve ranging and also serves as an aid in quality control for setting out. The theory is developed from the principles of the Optimum Point Method of curve ranging and the derivation of the CC by both empirical and theoritical methods are discussed. A simplified version of the formula is given at the end for ease of computation. The highlighted applications of the CC confirm this property as an invaluable tool for planning in curve ranging operations.
Applied Mathematics and Computation, 2006
In this paper, the difference equations will be employed to produce a polynomial which its roots are the nodes of Gauss quadrature rules. In this procedure, we obtain a system of nonlinear equations according to the concepts of precision degree of integration and the moments of order k. Hence the resulted polynomials obtained by difference equations have their roots as the nodes. Finally, some examples are given to show the application of the procedure.
The literature states that numerical method of lines (MOL) is a technique for solving partial differential equations (PDEs) by discretizing in all but one dimension. This paper will demonstrate (using an example) how to estimate the default accuracy of the MOL solution to a second order partial differential equation (PDE), being produced by a computer algebra system (CAS). This technique is easy enough to introduce to undergraduates doing a first course in PDEs.
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