Journal articles: 'Curve fitting technique'

1

Rajan, T. S., and S. Narayanaswamy. "A novel curve fitting technique applied to drying curves." Canadian Journal of Chemical Engineering 64, no. 6 (December 1986): 1033–34. http://dx.doi.org/10.1002/cjce.5450640624.

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Damos, Diane L. "Determining Transfer of Training Using Curve Fitting." Proceedings of the Human Factors Society Annual Meeting 32, no. 18 (October 1988): 1276–79. http://dx.doi.org/10.1177/154193128803201818.

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The purpose of this paper is to demonstrate the measurement of learning and transfer using a curve-fitting technique discussed in a 1985 Human Factors article by Spears. The data were collected during an experiment that determined if rotation skills could become automated with practice and if the skills could transfer between stimuli. The dependent variables of interest were the slope and intercept of the regression equation relating correct reaction time and degrees of rotation. Curve fitting was accomplished using a common statistical package, BMDP, and an IBM-XT. The curve-fitting technique showed large initial transfer of training on several variables that did not affect the asymptotic level of performance. In contrast standard transfer of training calculations indicated small positive transfer.

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Zehr, E. P., and M. Klimstra. "The reliability of a curve fitting technique for Hoffmann-reflex recruitment curve analysis." Journal of Biomechanics 39 (January 2006): S483—S484. http://dx.doi.org/10.1016/s0021-9290(06)84975-4.

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Motlagh, O., S. H. Tang, M. N. Maslan, Fairul Azni Jafar, and Maslita A. Aziz. "A novel graph computation technique for multi-dimensional curve fitting." Connection Science 25, no. 2-3 (June 2013): 129–38. http://dx.doi.org/10.1080/09540091.2013.851173.

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Hsieh, Hsun-Chang, and Wen-Tong Chang. "Virtual knot technique for curve fitting of rapidly varying data." Computer Aided Geometric Design 11, no. 1 (February 1994): 71–95. http://dx.doi.org/10.1016/0167-8396(94)90025-6.

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Hyun, Seokjeong, and Cheol Kim. "An efficient shape-preserving curve fitting technique for complex structures." Communications in Numerical Methods in Engineering 20, no. 9 (July 14, 2004): 737–46. http://dx.doi.org/10.1002/cnm.693.

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Xianping, Tu, Lei Xianqing, Ma Wensuo, Wang Xiaoyi, Hu Luqing, and Zuo Xiaolin. "The minimum zone fitting and error evaluation for the logarithmic curve based on geometry optimization approximation algorithm." Transactions of the Institute of Measurement and Control 41, no. 15 (July 3, 2019): 4380–86. http://dx.doi.org/10.1177/0142331219858855.

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The minimum zone fitting and error evaluation for the logarithmic curve has important applications. Based on geometry optimization approximation algorithm whilst considering geometric characteristics of logarithmic curves, a new fitting and error evaluation method for the logarithmic curve is presented. To this end, two feature points, to serve as reference, are chosen either from those located on the least squares logarithmic curve or from amongst measurement points. Four auxiliary points surrounding each of the two reference points are then arranged to resemble vertices of a square. Subsequently, based on these auxiliary points, a series of auxiliary logarithmic curves (16 curves) are constructed, and the normal distance and corresponding range of values between each measurement point and all auxiliary logarithmic curves are calculated. Finally, by means of an iterative approximation technique consisting of comparing, evaluating, and changing reference points; determining new auxiliary points; and constructing corresponding auxiliary logarithmic curves, minimum zone fitting and evaluation of logarithmic curve profile errors are implemented. The example results show that the logarithmic curve can be fitted, and its profile error can be evaluated effectively and precisely using the presented method.

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Ray, Aditi, Joydipta Banerjee, T. R. G. Kutty, Arun Kumar, and Srikumar Banerjee. "Construction of master sintering curve of ThO2 pellets using optimization technique." Science of Sintering 44, no. 2 (2012): 147–60. http://dx.doi.org/10.2298/sos1202147r.

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Sintering kinetics and densification behavior of pure ThO2 have been studied using high temperature dilatometer experiments at constant rate of heating. Sintering activation energy has been determined by Wang and Raj method. Master sintering curve (MSC) for densification is a functional sintering model that describes densification under arbitrary time temperature excursion of a particular material during sintering. MSC for pure ThO2 has been constructed by fitting experimental relative density versus work of sintering data with modified sigmoid function. Five independent parameters of the fitting function are determined by Nelder-Mead optimization technique with the objective of minimizing fitting error in terms of mean residual square. A FORTRAN program has been developed for efficient construction of best converged master curve. It is shown that activation energy of pure ThO2 found by MSC approach is consistent with those obtained by other methods.

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Holler, Farida, David H. Burns, and James B. Callis. "Direct Use of Second Derivatives in Curve-Fitting Procedures." Applied Spectroscopy 43, no. 5 (July 1989): 877–82. http://dx.doi.org/10.1366/0003702894202292.

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Most curve-fitting procedures deal with an unknown, variable baseline by modeling it with a function involving a number of parameters. In view of the facts that (1) there is often no analytically relevant information in the baseline, and (2) there is usually no functional form known, a priori, for the baseline, we have chosen to eliminate it by means of the second-derivative transformation. The resulting profile is deconvoluted by fitting it with the second derivative of the sum of an appropriate number of component curves. The utility of this procedure is demonstrated on simulated data with typical baselines and noise levels, and on real FT-IR data. Peak parameters (such as position, width, and area) obtained from this technique are comparable to those obtained by fitting the original spectrum with Lorentzian curves and a simple baseline. The major advantage of this procedure is the reduction in the number of parameters that must be optimized in the fitting method. Applications of the technique could eliminate contributions from other complex baseline profiles in the quantitative analysis of spectral components.

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Tang, Xiao-Ming, Chen Li, and Douglas J. Patterson. "A curve-fitting technique for determining dispersion characteristics of guided elastic waves." GEOPHYSICS 75, no. 3 (May 2010): E153—E160. http://dx.doi.org/10.1190/1.3420736.

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We have developed a novel curve-fitting method to estimate dispersion characteristics of guided elastic waves and investigate its application to field wireline and logging while drilling (LWD) acoustic data processing. In an elastic waveguide such as a fluid-filled borehole with a logging tool, the frequency dispersion of a guided-wave mode is characterized by a monotonically varying dispersion curve bounded by its low- and high-frequency limits. The detailed behavior of the curves relates to various elastic/acoustic parameters of the complicated waveguide structure. The novelty of the proposed technique is that it simulates the multiparameter dispersion curve using a simple analytical function that has only four parameters. By adjusting the four parameters to fit the actual wave dispersion data, the wave’s dispersion characteristics can be satisfactorily determined. The result of this simple approach leads to several important applications in acoustic logging. The first is to correct the dispersion effect in the shear-wave velocity from wireline dipole acoustic logging. The second application obtains P-wave velocity from the dispersive leaky compressional-wave data from wireline or LWD measurements. Third, the technique is applied to obtain shear-wave velocity from LWD quadrupole shear-wave logging. Finally, the technique is applicable to layered waveguide structures encountered in surface seismic exploration.

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Chen, Hung Jen, and Hao En Chueh. "Applying Real-Valued Genetic Algorithm on Curve Fitting Problem." Advanced Materials Research 121-122 (June 2010): 183–87. http://dx.doi.org/10.4028/www.scientific.net/amr.121-122.183.

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Curve fitting refers to the process of finding an appropriate function that fits a finite set of data points. Representing a set of data points by a function is quite beneficial in data analysis and reapplication, and this technique is often used in engineering and technical problems. Fitting accuracy and computational time are usually the most crucial factors to be taken care of in curve fitting problems. Previous researchers have demonstrated that genetic algorithms can effectively solve curve fitting problems, but the difficulty of parameter coding is also widely encountered in computational processes. Hence, this study addresses on applying real-valued genetic algorithm to deal with curve fitting problems. Detailed discussion is made on the optimization efficiency among various data, and finally, some key parameters to curve fitting results are found and presented.

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Chan, T. F. "Determination of the Torque-Speed Characteristic of an Induction Motor Using a Curve-Fitting Technique." International Journal of Electrical Engineering & Education 30, no. 4 (October 1993): 360–65. http://dx.doi.org/10.1177/002072099303000410.

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Determination of the torque-speed characteristic of an induction motor using a curve-fitting technique This paper describes the use of a curve-fitting technique to deduce the nominal torque-speed characteristic of a three-phase induction motor from the speed data obtained in a no-load acceleration test. Experimental results show that the fitted curve is reasonably close to the torque-speed characteristic obtained from an actual load test.

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13

Soliman, S. A., G. S. Christensen, and A. Rouhi. "A new technique for curve fitting based on minimum absolute deviations." Computational Statistics & Data Analysis 6, no. 4 (June 1988): 341–51. http://dx.doi.org/10.1016/0167-9473(88)90074-6.

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Niu, Chun Hui, and Yong Lv. "Chromatic Confocal Displacement Measurment Based on Correlation Algorithm." Applied Mechanics and Materials 446-447 (November 2013): 909–14. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.909.

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Chromatic confocal technique application in displacement measurement is studied theoretically and experimentally. a set of refractive lenses are designed and a measurement system is established. Correlation fitting method is proposed to fit spectrum curve and find peak wavelength. Results with use of correlation fitting method are compared with Gaussian and smoothing spline fitting methods. It indicate that correlation fitting method have higher extracting accuracy of peak wavelength and smaller RMSE of linear fitting due to narrower and smoother correlation curve.

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Bingi, Kishore, Rosdiazli Ibrahim, Mohd Noh Karsiti, Sabo Miya Hassam, and Vivekananda Rajah Harindran. "Frequency Response Based Curve Fitting Approximation of Fractional–Order PID Controllers." International Journal of Applied Mathematics and Computer Science 29, no. 2 (June 1, 2019): 311–26. http://dx.doi.org/10.2478/amcs-2019-0023.

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Abstract Fractional-order PID (FOPID) controllers have been used extensively in many control applications to achieve robust control performance. To implement these controllers, curve fitting approximation techniques are widely employed to obtain integer-order approximation of FOPID. The most popular and widely used approximation techniques include the Oustaloup, Matsuda and Cheraff approaches. However, these methods are unable to achieve the best approximation due to the limitation in the desired frequency range. Thus, this paper proposes a simple curve fitting based integer-order approximation method for a fractional-order integrator/differentiator using frequency response. The advantage of this technique is that it is simple and can fit the entire desired frequency range. Simulation results in the frequency domain show that the proposed approach produces better parameter approximation for the desired frequency range compared with the Oustaloup, refined Oustaloup and Matsuda techniques. Furthermore, time domain and stability analyses also validate the frequency domain results.

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Kalnicky, Dennis J. "A Combined Fundamental Alphas/Curve Fitting Algorithm for Routine XRF Sample Analysis." Advances in X-ray Analysis 29 (1985): 451–60. http://dx.doi.org/10.1154/s0376030800010570.

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AbstractAnalysis of sample composition and/or thickness in a routine, process-control or monitoring environment generally requires rapid turn-around time with minimal sample handling. X-ray Fluorescence (XRF) is well-suited for these kinds of analyses and has been applied to various bulk and thin sample applications (1-7). This technique is rapid, precise, non-destructive, and requires minimal sample handling.X-ray Fluorescence is generally considered a secondary analysis technique, that is, instrumentation must be calibrated using known standards before unknown samples may be analyzed (quantitative analysis). Continuing work on standardless approaches, particularly for Energy-Dispersive XRF (EOXRF) systems, relax this requirement for some samples but the large share of XRF analyses still require calibration with standards. A number of mathematical and non-matheraatical techniques have been devised to calibrate XRF measurements for many different sample types (1,2,8,9).

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Balamesh, Ahmed S., and Ali M. Rushdi. "Atomic Formulation of the Boolean Curve Fitting Problem." International Journal of Mathematical, Engineering and Management Sciences 7, no. 5 (October 1, 2022): 670–780. http://dx.doi.org/10.33889/ijmems.2022.7.5.044.

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Boolean curve fitting is the process of finding a Boolean function that takes given values at certain points in its Boolean domain. The problem boils down to solving a set of ‘big’ Boolean equations that may or may not be consistent. The usual formulation of the Boolean curve fitting problem is quite complicated, indeed. In this paper, we formulate the Boolean curve fitting problem using the technique of atomic decomposition of Boolean equations. This converts the problem into a set of independent switching equations. We present the solution of these switching equations and express the solution in very simple and compact forms. We also present the consistency and uniqueness conditions for this problem again in very compact forms. A few illustrative examples are given. These examples clearly pinpoint the simplicity gained by the Boolean-equation solving step within the overall Boolean-fitting procedure. The method presented here can be applied to the design of Boolean functions for cryptographic systems.

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Gavin, H. P., R. D. Hanson, and F. E. Filisko. "Electrorheological Dampers, Part II: Testing and Modeling." Journal of Applied Mechanics 63, no. 3 (September 1, 1996): 676–82. http://dx.doi.org/10.1115/1.2823349.

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Electrorheological (ER) materials develop yield stresses on the order of 5–10 kPa in the presence of strong electric fields. Viscoelastic and yielding material properties can be modulated within milli-seconds. An analysis of flowing ER materials in the limiting case of fully developed steady flow results in simple approximations for use in design. Small-scale experiments show that these design equations can be applied to designing devices in which the flow is unsteady. More exact models of ER device behavior can be determined using curve-fitting techniques in multiple dimensions. A previously known curve-fitting technique is extended to deal with variable electric fields. Experiments are described which illustrate the potential for ER devices in large-scale damping applications and the accuracy of the modeling technique.

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Daud, Hanita, Radzuan Razali, M. Ridhwan O. Zaki, and Afza Shafie. "Curve Fitting Using Logarithmic Function for Sea Bed Logging Data." Journal of Computational and Theoretical Nanoscience 13, no. 10 (October 1, 2016): 7448–54. http://dx.doi.org/10.1166/jctn.2016.5738.

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The aim of this research work is to conduct curve fitting using mathematical equations that relate location of the hydrocarbon (HC) at different depths to different frequencies. COMSOL MultiPhysics software was used to generate models of the seabed logging technique which consists of air, sea water, and sediment and HC layer. Seabed Logging (SBL) is a technique to find the resistive layers under seabed by transmitting low frequency of EM waves through sea water and sediment. As HC is known to have high resistivity which is about 30–500 Ωm, EM waves will be guided and reflected back and detected by the receiver that are placed on the seafloor. In SBL, low frequency is used to obtain greater wavelength which allows EM waves to penetrate at longer distance and each frequency used has different skin depth. The frequencies used in this project were 0.5 Hz, 0.25 Hz, 0.125 Hz and 0.0625 Hz and the depths of the HC were varied from 1000 m to 3000 m with increment of 250 m. Data generated from COMSOL software was extracted for the set up with and without HC and trend lines using logarithmic functions were developed and R2 were calculated for each equation and curve. The calculated R2 was compared between data with HC to no HC at each depth and it was found that the calculated R2 values were very well fitted for deeper HC depth. This indicates that as depth of HC is higher, it is difficult to distinguish data with and without HC presence; and perhaps a new technique can be explored.

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Su, Z. H., J. Gan, Q. K. Yu, Q. H. Zhang, Z. H. Liu, and J. M. Bao. "High-resolution fiber optic temperature sensors using nonlinear spectral curve fitting technique." Review of Scientific Instruments 84, no. 4 (April 2013): 045002. http://dx.doi.org/10.1063/1.4802684.

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Soliman, S. A., and G. S. Christensen. "Digital Analysis of Power Systems Dynamic Oscillation Using a Curve Fitting Technique." Electric Machines & Power Systems 20, no. 4 (July 1992): 309–20. http://dx.doi.org/10.1080/07313569208909596.

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Pattanadech, Norasage, and Peerawut Yutthagowith. "Fast curve fitting algorithm for parameter evaluation in lightning impulse test technique." IEEE Transactions on Dielectrics and Electrical Insulation 22, no. 5 (October 2015): 2931–36. http://dx.doi.org/10.1109/tdei.2015.005165.

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Ding, Lei, Wen-De Zhong, Chao Lu, and Yixin Wang. "New bit-error-rate monitoring technique based on histograms and curve fitting." Optics Express 12, no. 11 (2004): 2507. http://dx.doi.org/10.1364/opex.12.002507.

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Kohl, Alexandra S., Adriana Bastos Conforto, Werner J. Z’Graggen, and Alain Kaelin-Lang. "An integrative transcranial magnetic stimulation mapping technique using non-linear curve fitting." Journal of Neuroscience Methods 157, no. 2 (October 2006): 278–84. http://dx.doi.org/10.1016/j.jneumeth.2006.04.018.

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Yang, Jin-long, Peng Li, and Hong-wei Ge. "Extended Target Shape Estimation by Fitting B-Spline Curve." Journal of Applied Mathematics 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/741892.

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Taking into account the difficulty of shape estimation for the extended targets, a novel algorithm is proposed by fitting the B-spline curve. For the single extended target tracking, the multiple frame statistic technique is introduced to construct the pseudomeasurement sets and the control points are selected to form the B-spline curve. Then the shapes of the extended targets are extracted under the Bayes framework. Furthermore, the proposed shape estimation algorithm is modified suitably and combined with the probability hypothesis density (PHD) filter for multiple extended target tracking. Simulations show that the proposed algorithm has a good performance for shape estimate of any extended targets.

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Pearson, G. W. "Precise Calendrical Dating of Known Growth-Period Samples Using a ‘Curve Fitting’ Technique." Radiocarbon 28, no. 2A (1986): 292–99. http://dx.doi.org/10.1017/s0033822200007396.

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Absolute high-precision radiocarbon time-scale calibration is now available and is shown by Stuiver and Pearson (1986) and Pearson and Stuiver (1986) to be internationally valid. The technique of curve fitting presented in this paper shows how certain samples may be dated calendrically to within a very narrow band width ca ± 20 years, at time periods when single sample analysis would give ambiguous calendrical conversion. Samples of known deposition rate covering a time span of >50 years are subdivided to produce a ‘floating curve’ and this curve is then ‘wiggle matched’ with the high-precision calibration to give a precise calendrical age.

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Solís, Mario, Mario Algaba, and Pedro Galvín. "Crack Location in Beams Using Wavelet Analysis." Key Engineering Materials 569-570 (July 2013): 1021–28. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.1021.

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This paper applies a methodology for damage detection in beams proposed by the authors. The methodology is based on a continuous wavelet analysis of the difference of mode shapes between a damaged state and a reference state. The wavelet transform is used to detect changes in the mode shapes induced by damage. The wavelet coefficients for each mode are added up and normalized to unity in order to obtain a clear and precise damage assessment. A curve fitting approach reduces the effect of experimental noise in the mode shapes. When only a small number of measuring points are available, a cubic spline interpolation technique provides additional “virtual” measuring points. The interpolation technique may also be used when measuring points are not equally spaced. It also serves as a softening technique of the mode shapes when applied, and no curve fitting approach is used in that case. An antisymmetric extension at both ends of the mode shapes is used to avoid the edge effect in the wavelet transform. The paper presents the results obtained for steel beams with an induced crack. Several sizes and locations of the crack have been considered. The paper addresses several issues affecting the accuracy of the proposed methodology, such as the number of measuring points and the effect of the extension, curve fitting and interpolation techniques.

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SHIN, HYUNG-SEOP, JONG-SEO PARK, and HAE-MOO LEE. "CURVE FITTING IN THE TRANSITION REGION OF CHARPY IMPACT DATA." International Journal of Modern Physics B 22, no. 09n11 (April 30, 2008): 1496–503. http://dx.doi.org/10.1142/s0217979208046980.

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The toughness data obtained from Charpy impact tests are presented by a temperature-energy relationship. Data fitting for quantitative evaluation of the transition temperature, upper shelf energy and ductile-brittle transition, in other words, the representation with general mathematical model equation for energy variation according to the temperature is necessary. In this study, the Charpy impact tests to two representative steels were carried out as a research work for the material property standardization technique development. The fitting procedure of the scattering in data according to materials and temperature in the transition region was described. The data fitting procedure using the tangent hyperbolic function was established through variances treatment in the transition region.

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Hosseini, S. Abolfazl, and Hassan Ghassemian. "Hyperspectral Data Feature Extraction Using Rational Function Curve Fitting." International Journal of Pattern Recognition and Artificial Intelligence 30, no. 01 (December 30, 2015): 1650001. http://dx.doi.org/10.1142/s0218001416500014.

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A feature reduction technique is proposed for the hyperspectral (HS) data classification problem. The new features have been developed through a curve fitting step which fits specific rational function approximations to every spectral response curve (SRC) of HS image pixels. Then, the coefficients of the numerator and denominator polynomials of these fitted functions are considered as new extracted features. The method concentrates on the geometrical nature of SRCs and is utilizing the information that exists in sequence discipline — ordinance of reflectance coefficients in SRC — which has not been addressed by many other statistical analysis based methods. Maximum likelihood (ML) classification results show that the proposed method provides better classification accuracies compared to some basic and state-of-the-art feature extraction methods. Moreover, the proposed algorithm has the capability of being applied individually and simultaneously to all pixels of image.

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Speakman, J. R., and P. A. Racey. "Measurement of CO2 production by the doubly labeled water technique." Journal of Applied Physiology 61, no. 3 (September 1, 1986): 1200–1202. http://dx.doi.org/10.1152/jappl.1986.61.3.1200.

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Recent applications of the doubly labeled water technique to the study of human metabolism have employed multiple sampling of body water over protracted periods, rather than the more traditional method of taking only an initial and final sample for isotopic analysis. In addition fractional turnovers of the body pools have been estimated by fitting curves to the sequential log-converted isotope enrichment against time. By manipulation of data collected in the field in a study of metabolism of vespertilionid bats, it is shown the curve-fitting technique results in an accurate estimate of CO2 production only when the rate of CO2 production is constant. Biologically realistic nonsteady-state conditions result in errors in estimates of CO2 production of up to 30%. In conditions where CO2 production is known to be temporally variable, the more traditional two-sample method may provide a more accurate estimate of CO2 production.

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Zaman, Mohammad Asif, and Shuvro Chowdhury. "Modified Bézier Curves with Shape-Preserving Characteristics Using Differential Evolution Optimization Algorithm." Advances in Numerical Analysis 2013 (March 13, 2013): 1–8. http://dx.doi.org/10.1155/2013/858279.

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A parametric equation for a modified Bézier curve is proposed for curve fitting applications. The proposed equation contains shaping parameters to adjust the shape of the fitted curve. This flexibility of shape control is expected to produce a curve which is capable of following any sets of discrete data points. A Differential Evolution (DE) optimization based technique is proposed to find the optimum value of these shaping parameters. The optimality of the fitted curve is defined in terms of some proposed cost parameters. These parameters are defined based on sum of squares errors. Numerical results are presented highlighting the effectiveness of the proposed curves compared with conventional Bézier curves. From the obtained results, it is observed that the proposed method produces a curve that fits the data points more accurately.

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Miah, Mohammad Badrul Alam, Suryanti Awang, Md Mustafizur Rahman, A. S. M. Sanwar Hosen, and In-Ho Ra. "A New Unsupervised Technique to Analyze the Centroid and Frequency of Keyphrases from Academic Articles." Electronics 11, no. 17 (September 2, 2022): 2773. http://dx.doi.org/10.3390/electronics11172773.

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Automated keyphrase extraction is crucial for extracting and summarizing relevant information from a variety of publications in multiple domains. However, the extraction of good-quality keyphrases and the summarising of information to a good standard have become extremely challenging in recent research because of the advancement of technology and the exponential development of digital sources and textual information. Because of this, the usage of keyphrase features for keyphrase extraction techniques has recently gained tremendous popularity. This paper proposed a new unsupervised region-based keyphrase centroid and frequency analysis technique, named the KCFA technique, for keyphrase extraction as a feature. Data/datasets collection, data pre-processing, statistical methodologies, curve plotting analysis, and curve fitting technique are the five main processes in the proposed technique. To begin, the technique collects multiple datasets from diverse sources, which are then input into the data pre-processing step by utilizing some text pre-processing processes. Afterward, the region-based statistical methodologies receive the pre-processed data, followed by the curve plotting examination and, lastly, the curve fitting technique. The proposed technique is then tested and evaluated using ten (10) best-accessible benchmark datasets from various disciplines. The proposed approach is then compared to our available methods to demonstrate its efficacy, advantages, and importance. Lastly, the results of the experiment show that the proposed method works well to analyze the centroid and frequency of keyphrases from academic articles. It provides a centroid of 706.66 and a frequency of 38.95% in the first region, 2454.21 and 7.98% in the second region, for a total frequency of 68.11%.

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Ashok, S. Denis, and G. L. Samuel. "Least square curve fitting technique for processing time sampled high speed spindle data." International Journal of Manufacturing Research 6, no. 3 (2011): 256. http://dx.doi.org/10.1504/ijmr.2011.041129.

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Lu, S. H., and J. R. Selman. "Kinetics of Hydrogen Oxidation in Molten Carbonate: Application of Computer Curve‐Fitting Technique." Journal of The Electrochemical Society 136, no. 4 (April 1, 1989): 1068–74. http://dx.doi.org/10.1149/1.2096786.

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Wan, Xiangkui, Yan Li, Chong Xia, Minghu Wu, Jin Liang, and Na Wang. "A T-wave alternans assessment method based on least squares curve fitting technique." Measurement 86 (May 2016): 93–100. http://dx.doi.org/10.1016/j.measurement.2016.01.046.

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Pan, Yaxi, and Jian Dong. "Design and Optimization of an Ultrathin and Broadband Polarization-Insensitive Fractal FSS Using the Improved Bacteria Foraging Optimization Algorithm and Curve Fitting." Nanomaterials 13, no. 1 (January 1, 2023): 191. http://dx.doi.org/10.3390/nano13010191.

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A frequency-selective surface (FSS) optimization method combining a curve-fitting technique and an improved bacterial foraging optimization (IBFO) algorithm is proposed. In the method, novel Koch curve-like FSS and Minkowski fractal islands FSS were designed with a desired resonance center frequency and bandwidth. The bacteria foraging optimization (BFO) algorithm is improved to enhance the performance of the FSS. A curve-fitting technique is provided to allow an intuitive and numerical analysis of the correspondence between the FSS structural parameters and the frequency response. The curve-fitting results are used to evaluate the fitness function of the IBFO algorithm, replacing multiple repeated calls to the electromagnetic simulation software with the curve-fitting equation and thus speeding up the design process. IBFO is compared with the classical BFO algorithm, the hybrid BFO-particle swarm optimization algorithm (BSO), and the artificial bee colony algorithm (ABC) to demonstrate its superior performance. The designed fractal FSS is fabricated and tested to verify the experimental results. The simulation and measurement results show that the proposed FSS has a fractional bandwidth of 91.7% in the frequency range of 3.41–9.19 GHz (S, C, and X-bands). In addition, the structure is very thin, with only 0.025λ and 0.067λ at the lowest and highest frequencies, respectively. The proposed fractal FSS has shown stable performance for both TE and TM polarizations at oblique incidence angles up to 45°. according to simulations and measurements.

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Krepelka, Pavel, Iveta Hynstova, Roman Pytel, Fernando Pérez-Rodríguez, Jean-Michel Roger, and Petr Drexler. "Curve fitting in Fourier transform near infrared spectroscopy used for the analysis of bacterial cells." Journal of Near Infrared Spectroscopy 25, no. 3 (May 2, 2017): 151–64. http://dx.doi.org/10.1177/0967033517705032.

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Infrared spectroscopy is a prominent molecular technique for bacterial analysis. Within its context, near infrared spectroscopy in particular brings benefits over other vibrational approaches; these advantages include, for example, lower sensitivity to water, high penetration depth and low cost. However, near infrared spectroscopy is not popular within microbiology, because the spectra of organic samples are difficult to interpret. We propose a comparison of spectral curve-fitting methods, namely, techniques that facilitate the interpretation of most peaks, simplify the spectra and improve the prediction of bacterial species from the relevant near infrared spectra. The performances of three common curve-fitting algorithms and the technique based on the differential evolution were compared via a synthesized experimental spectrum. Utilizing the obtained results, the spectra of three different bacterial species were curve fit by optimized algorithm. The proposed algorithm decomposed the spectra to specific absorption peaks, whose parameters were estimated via the differential evolution approach initialized through Levenberg-Marquardt optimization; subsequently, the spectra were classified with conventional procedures and using the parameters of the revealed peaks. On a limited data set, the correct classification rate computed by partial least squares discriminant analysis was 95%. When we employed the peak parameters for the classification, the rate corresponded to 91.7%. According to the Gaussian formula, the parameters comprise the spectral peak position, amplitude and width. The most important peaks for bacterial discrimination were identified by analysis of variance and interpreted as N–H stretching bonds in proteins, cis bonds and CH2 absorption in fatty acids. We examined some aspects of the behaviour of standard curve-fitting algorithms and proposed differential evolution to optimize the fitting process. Based on the correct use of these algorithms, the near infrared spectra of bacteria can be interpreted and the full potential of near infrared spectroscopy in microbiology exploited.

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Tan, Wen Jia, Jen Feng Khor, Lloyd Ling, and Yuk Feng Huang. "Exploratory Research of New Curve Number System." E3S Web of Conferences 65 (2018): 07005. http://dx.doi.org/10.1051/e3sconf/20186507005.

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In the past, the CN was determined through SCS handbook. In order to determine runoff prediction using SCS-CN model, selection of CN is important. However, the conventional CN methodology with inappropriate CN selection often produces inconsistent runoff estimation. Thus, the new direct curve number derivation technique based on rainfall-runoff datasets with supervised numerical optimization technique under the guide of inferential statistics was developed to improve the accuracy of surface runoff prediction. Furthermore, the two decimal point CN system was proposed in this study. The optimum CN of Melana site is 90.45 at alpha 0.01 with BCa 99 % confidence interval range from 90.45 to 95.12. The regional specific calibrated SCS-CN model with two decimal point CN derivation technique is out-performed the runoff prediction of conventional SCS-CN model and the asymptotic curve number fitting method.

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KOUTSOUGERAS, CRIS, and GEORGE PAPADOURAKIS. "COUPLING SUPERVISED AND UNSUPERVISED TECHNIQUES IN TRAINING FEED-FORWARD NETS." International Journal on Artificial Intelligence Tools 01, no. 01 (March 1992): 37–55. http://dx.doi.org/10.1142/s0218213092000120.

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A popular approach to training feed-forward nets is to treat the problem of adaptation as a function approximation and to use curve fitting techniques. We discuss here the problems which the use of pure curve fitting techniques entail for the generalization capability and robustness of the net. These problems are in general inherently associated with the use of pure supervised learning techniques. We argue that a better approach to the training of feed-forward nets is to use adaptive techniques that combine properties of both supervised and unsupervised learning. A new formulation of the training problem is presented here. According to this formulation the net is viewed as two coupled sub-nets the first of which is trained by an unsupervised learning technique and the second by a supervised one. The same formulation gives rise to analytic expressions of the goals of the adaptation and leads to a new method for the adaptation of feed-forward nets.

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Watkin, Andrew T., and W. Wesley Eckenfelder. "A Technique to Determine Unsteady-State Inhibition Kinetics in the Activated Sludge Process." Water Science and Technology 21, no. 6-7 (June 1, 1989): 593–602. http://dx.doi.org/10.2166/wst.1989.0261.

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A technique for rapidly determining Monod and inhibition kinetic parameters in activated sludge is evaluated. The method studied is known as the fed-batch reactor technique and requires approximately three hours to complete. The technique allows for a gradual build-up of substrate in the test reactor by introducing the substrate at a feed rate greater than the maximum substrate utilization rate. Both inhibitory and non-inhibitory substrate responses are modeled using a nonlinear numerical curve-fitting technique. The responses of both glucose and 2,4-dichlorophenol (DCP) are studied using activated sludges with various acclimation histories. Statistically different inhibition constants, KI, for DCP inhibition of glucose utilization were found for the various sludges studied. The curve-fitting algorithm was verified in its ability to accurately retrieve two kinetic parameters from synthetic data generated by superimposing normally distributed random error onto the two parameter numerical solution generated by the algorithm.

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Unruh, V., and P. Krishnaswami. "A Computer-Aided Design Technique for Semi-Automated Infinite Point Coupler Curve Synthesis of Four-Bar Linkages." Journal of Mechanical Design 117, no. 1 (March 1, 1995): 143–49. http://dx.doi.org/10.1115/1.2826099.

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At the present time, there are no satisfactory computer-aided solution schemes for solving the infinite point coupler curve synthesis problem (i.e., the problem of synthesizing a four-bar linkage whose coupler curve best approximates a fully specified closed trajectory). In order to develop a programmable solution process for this class of problems, it is necessary to devise a way of storing a catalog of coupler curves in a computer database. In addition, comparison procedures must be developed for detecting geometric similarities between curves; these procedures must be capable of observing similarities in the shapes of curves which may be scaled or oriented differently. In this paper, a data representation scheme based on uniform periodic B-splines is proposed as a viable means of storing coupler curves in a database. Automated procedures for fitting B-splines to coupler cures or other closed curves are also developed. The paper also presents a set of algorithms for comparing the shapes of curves based on the control polygons of their B-spline approximations. These algorithms are implemented in a computer program that is an effective tool for semi-automated computer-aided solution of the infinite point coupler curve synthesis problem. Example problems solved using this program are discussed, along with some suggestions for further work on this topic.

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Ni, P. A., R. M. More, and F. M. Bieniosek. "Reliability of temperature determination from curve-fitting in multi-wavelength pyrometery." Laser and Particle Beams 31, no. 2 (June 2013): 333–36. http://dx.doi.org/10.1017/s0263034612001103.

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AbstractThis paper examines the reliability of a widely used method for temperature determination by multi-wavelength pyrometry. In recent warm dense matter experiments with ion-beam heated metal foils, we found that the statistical quality of the fit to the measured data is not necessarily a measure of the accuracy of the inferred temperature. We found a specific example where a second-best fit leads to a more realistic temperature value. The physics issue is the wavelength-dependent emissivity of the hot surface. We discuss improvements of the multi-frequency pyrometry technique, which will give a more reliable determination of the temperature from emission data.

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Kaushal, Sandeep, Bambam Kumar, Prabhat Sharma, and Dharmendra Singh. "Real time Adaptive Approach for Hidden Targets Shape Identification using through Wall Imaging System." Defence Science Journal 71, no. 03 (May 17, 2021): 395–402. http://dx.doi.org/10.14429/dsj.71.16696.

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In Through-wall Imaging (TWI) system, shape-based identification of the hidden target behind the wall made of any dielectric material like brick, cement, concrete, dry plywood, plastic and Teflon, etc. is one of the most challenging tasks. However, it is very important to understand that the performance of TWI systems is limited by the presence of clutter due to the wall and also transmitted frequency range. Therefore, the quality of obtained image is blurred and very difficult to identify the shape of targets. In the present paper, a shape-based image identification technique with the help of a neural network and curve-fitting approach is proposed to overcome the limitation of existing techniques. A real time experimental analysis of TWI has been carried out using the TWI radar system to collect and process the data, with and without targets. The collected data is trained by a neural network for shape identification of targets behind the wall in any orientation and then threshold by a curve-fitting method for smoothing the background. The neural network has been used to train the noisy data i.e. raw data and noise free data i.e. pre-processed data. The shape of hidden targets is identified by using the curve fitting method with the help of trained neural network data and real time data. The results obtained by the developed technique are promising for target identification at any orientation.

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Sun, Dejian, Bing Wang, Xiong Hu, and Wei Wang. "An Online Degradation Feature Extraction Technique for Shore Bridge Gearbox Based on Morphological Fractal Dimension and Sliding Window Weibull Fitting." Shock and Vibration 2019 (October 30, 2019): 1–9. http://dx.doi.org/10.1155/2019/9216809.

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Shore bridge and other port cranes have some working condition characters including high speed, heavy load, and large impact. In order to solve the degradation feature extraction issue of hoisting mechanism gearbox, an online degradation feature extraction technique based on morphological fractal dimension and sliding window Weibull fitting is proposed. Firstly, taking the vibration energy spectrum collecting from the gearbox as the online data source, the fractal dimension of the vibration energy spectrum during an analysis period is calculated and a fractal evolution curve is obtained. A three-parameter Weibull fitting on the fractal curve within a sliding window after setting the window’s width and step size is performed. The scale parameter of the Weibull fitting model is introduced as the performance degradation feature. The effectiveness of the technique is verified by the full-life vibration data of hoisting gearbox from Shanghai Port Group. The results show that the morphological fractal dimension is able to describe the fractal complexity of the vibration energy spectrum. The scale parameter of Weibull distribution is able to reflect the performance degradation trend of fractal curve smoothly, which lays a theoretical foundation for further solving the problem of online health assessment.

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Agnihotri, SP, and Laxman Madhavrao Waghmare. "Iterative algorithm and curve fitting technique for tuning with time delay system PID controller." Journal of Intelligent & Fuzzy Systems 29, no. 4 (October 23, 2015): 1527–37. http://dx.doi.org/10.3233/ifs-151632.

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AlJanabi, Kadhim AlJanabi, Mansoor Habeebi Habeebi, and Nawras Riyadh Neamah. "An Approach for Solving Missing Values in Data Set Using Clustering-Curve Fitting Technique." Journal of Kufa for Mathematics and Computer 2, no. 2 (December 1, 2014): 87–105. http://dx.doi.org/10.31642/jokmc/2018/0202012.

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Missing values in data sets represent one of the greatest challenge in analyzing data to extract knowledge from the data set. The work in this paper presents a new approach for solving the missing values problems by using and merging two different techniques; clustering (K-means and Expectation Maximization) and curve fitting. More than twenty thousand records of real health data set collected from different Iraqi hospitals were used to create and test the proposed approach that showed better results than the most popular techniques for estimation missing values such as most common values, overall overage, class average, and class most common values. Different software were used in the proposed work including WEKA (Waikato Environment for Knowledge Analysis), Matlab, Excel and C++.

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Jónás, Tamás, Gábor Árva, and Zsuzsanna Eszter Tóth. "Forecasting Failure Rates of Electronic Goods by Using Decomposition and Fuzzy Clustering of Empirical Failure Rate Curves." Periodica Polytechnica Social and Management Sciences 26, no. 1 (July 3, 2017): 10. http://dx.doi.org/10.3311/ppso.9026.

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In this paper a novel methodology founded on the joint application of analytic decomposition of empirical failure rate time series and soft computational techniques is introduced in order to predict bathtub-shaped failure rate curves of consumer electronic goods. Empirical failure rate time series are modeled by a flexible function the parameters of which have geometric interpretations, and so the model parameters grab the characteristics of bathtub-shaped failure rate curves. The so-called typical standardized failure rate curve models, which are derived from the model functions through standardization and fuzzy clustering processes, are applied to predict failure rate curves of consumer electronics in a method that combines analytic curve fitting and soft computing techniques. The forecasting capability of the introduced method was tested on real-life data. Based on the empirical results from practical applications, the introduced method can be considered as a new, alternative reliability prediction technique the application of which can support the electronic repair service providers to plan their resources in the long run.

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Weng, Sen Chyi, Gow Yi Tzou, and Bor Lih Kuo. "Bulging Investigation of Cylinder Compression Forming Using Upper Bound Analysis." Advanced Materials Research 939 (May 2014): 283–90. http://dx.doi.org/10.4028/www.scientific.net/amr.939.283.

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Bulging deformation during cylinder compression forming results in geometrical imprecision and flow stress prediction error. Consequently, the present study proposes a hybrid technique comprising the Upper Bound Method (UBM) and geometrical fitting method. It is noted that a volume conservation constraint and an elliptical curve-fitting method with UBM for predicting both the compression force and the bulge profile. It is shown that the predicted results for the compression force based on UBM under certain reduction ratios of 30%, 40%, 50% and 60% are in good agreement with those obtained by experiment, Finite Element Method (FEM), and Slab Method (SM). In addition, it is revealed that the use of an elliptical curve-fitting technique provides a reasonable approximation of the bulge profile obtained by experiment and FEM simulations. Generally, the proposed method effectively provides a low-cost, computationally straightforward means of estimating the compression force and bulge profile in cylinder compression forming. Therefore it can be utilized as the widespread applications in the metal forming field.

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Abuelma'atti, Muhammad Taher. "Harmonic and Intermodulation Performance of Nonlinear Electronic Circuits." Active and Passive Electronic Components 21, no. 2 (1998): 87–105. http://dx.doi.org/10.1155/1998/52606.

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A unified technique for mathematical modelling of the input output characteristics of nonlinear electronic circuits is presented. This technique can be easily implemented using simple hand computations without recourse to standard curve-fitting techniques, which invariably requires extensive computing facilities and well-developed software. The mathematical model, basically a sine-series function, can easily yield closed-form series expressions for the amplitudes of the output components resulting from a multisinusoidal input signal to nonlinear electronic circuits. The technique is very helpful in analysing nonlinear electronic circuits under different scenarios of input signals.

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Zhang, Gao Wei, Guan Wei Zhang, and Qing Zhang. "Research on Spiral Drill Stabilizer Wear-Resisting Layer Repair Technology." Applied Mechanics and Materials 157-158 (February 2012): 373–76. http://dx.doi.org/10.4028/www.scientific.net/amm.157-158.373.

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This paper introduced the repair methods of wear-resistant layer of the drilling tool stabilizer, and proposed a simple fitting method for spiral drill stabilizer wear belt, fitting of spatial spiral surface is essence of the space spiral curve fitting, for a pitch fixed spiral can be expanded to two-dimensional line, and then using interpolation technique can control drill stabilizer and repair work head of joint motion, the synthesis of these two motions is the space spiral.

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Journal articles on the topic 'Curve fitting technique'

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