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Analysis of Surface Plasmon Resonance Curves with a Novel Sigmoid-Asymmetric fitting algorithm

SENSORS 2015年第10期15卷 25385-25398页

作者： Jang, Daeho Chae, Geunhyoung Shin, Sehyun Korea Univ Sch Mech Engn Seoul 136701 South Korea Sungkyunkwan Univ Coll Informat & Commun Engn Suwon 440476 South Korea

The present study introduces a novel curve-fitting algorithm for surface plasmon resonance (SPR) curves using a self-constructed, wedge-shaped beam type angular interrogation SPR spectroscopy technique. Previous fitting approaches such as asymmetric and polynomial equations are still unsatisfactory for analyzing full SPR curves and their use is limited to determining the resonance angle. In the present study, we developed a sigmoid-asymmetric equation that provides excellent curve-fitting for the whole SPR curve over a range of incident angles, including regions of the critical angle and resonance angle. Regardless of the bulk fluid type (i.e., water and air), the present sigmoid-asymmetric fitting exhibited nearly perfect matching with a full SPR curve, whereas the asymmetric and polynomial curve fitting methods did not. Because the present curve-fitting sigmoid-asymmetric equation can determine the critical angle as well as the resonance angle, the undesired effect caused by the bulk fluid refractive index was excluded by subtracting the critical angle from the resonance angle in real time. In conclusion, the proposed sigmoid-asymmetric curve-fitting algorithm for SPR curves is widely applicable to various SPR measurements, while excluding the effect of bulk fluids on the sensing layer.

关键词： surface plasmon resonance fitting algorithm sigmoid-asymmetric critical angle resonance angle

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High-precision Resistance Calibrator Error Compensation Method Research Based on fitting algorithm 12

High-precision Resistance Calibrator Error Compensation Meth...

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12th IEEE Conference on Industrial Electronics and Applications (ICIEA)

作者： Yang, Chunling Yu, Jiajian Zhu, Min Harbin Inst Technol Sch Elect Engn & Automat Harbin Heilongjiang Peoples R China

ISBN: (纸本)9781509061617

In the design of high-precision resistance calibrator, using the fitting algorithm to fit the resistance control curve is an important method of error compensation. The interpolation method and the approximation method are commonly used in the fitting algorithm. However, there exist overmuch test points and noise problems in the high accuracy resistance calibrator, which leads to the problem of low accuracy of interpolation and approximation. In order to realize accurately fitting, a fitting algorithm based on least squares approximation was used to fit the curve. The results show that the proposed algorithm can be applied to the error correction of the resistance calibrator, which greatly improves its accuracy.

关键词： fitting algorithm high-precision resistance calibration error compensation

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Study of the Curve fitting algorithm for NC Machining Graphics

Study of the Curve Fitting Algorithm for NC Machining Graphi...

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8th International Conference on Computer Science and Education (ICCSE)

作者： Xu Jishui Zhang Zipeng Wang Shuqing Wuhan Univ Sch Power & Mech Engn Wuhan 430072 Peoples R China

ISBN: (纸本)9781467344630;9781467344647

In the process of NC machining, the precise computation of machining graphical path is the key to guarantee machining precision. In curve fitting, it is difficult to fit curve just only using straight line. The combining both arc and line may get good fitting effect in fitting curve. But it leads to complicated calculation in fitting. Aiming at this problem, multi-dimensional fuzzy reasoning algorithm is proposed in this paper to optimize the calculation process and improve the fitting curve speed and accuracy. The designed multidimensional fuzzy inference algorithm makes the computation of the curve fitting simplicity and preciseness when the model structure is used in programming. Test results show that the designed way can well approximate the original graphics and well optimize the number of segment in the fitting process.

关键词： curve fitting NC machining graphics fuzzy reasoning fitting algorithm

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Measurement of Temperature Dependence Complex Permittivity Based on fitting algorithm of Terminal short circuit

Measurement of Temperature Dependence Complex Permittivity B...

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International Applied-Computational-Electromagnetics-Society Symposium - China (ACES)

作者： Li, Qiangqiang Li, Hongliang Liu, Dawei Bai, Ming Beihang Univ Microwave Engn Lab Beijing 100083 Peoples R China

ISBN: (纸本)9780996007849

Aiming at the measurement of temperature dependence complex permittivity of low loss material, a new fitting algorithm is designed based on terminal short circuit method. The calculation process is simpler and remain accuracy. At the same time the temperature dependence test system is designed and built in this paper. The accuracy of the algorithm and the system is verified. The results show that the complex permittivity of low loss materials can be accurately measured from room temperature to 250 degrees C under the wide band.

关键词： low loss material Complex permittivity high temperature terminal short circuit fitting algorithm

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Study on surface fitting algorithm applied in manufacturing of CFETR VV

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FUSION ENGINEERING AND DESIGN 2021年 170卷 112689-112689页

作者： Fan, Xiaosong Gu, Yongqi Ji, Haibiao Zheng, Yuanyang Liu, Zhihong Wu, Jiefeng Ma, Jianguo Huainan New Energy Res Ctr Anhui Prov Key Lab Special Welding Technol Huainan 232063 Peoples R China Chinese Acad Sci Inst Plasma Phys Hefei 230031 Peoples R China Shenzhen Univ Coll Engn Key Lab Optoelectron Device & Syst Minist Educ & Guangdong Prov Shenzhen 518060 Peoples R China Shenzhen Univ Adv Energy Res Ctr Shenzhen 518060 Peoples R China

During the manufacturing process of China Fusion Engineering Test Reactor vacuum vessel mock-up, the dimensional accuracy and the contour accuracy of the vacuum vessel decrease inevitably due to manufacturing and assembly errors. To solve this problem, measuring and fitting method is used and new reference points are established. For nonuniform distribution of deviations caused by the asymmetric structure of the vacuum vessel sector, least square algorithm is improved by introducing weight factors from the least squares method. With the improved fitting algorithm, the error distributions of simulation results and deviations after fitting of the 1/32 vacuum vessel sector become more even, and the error maximums are reduced. Results show that measuring and fitting method with improved algorithm is effective in improving the manufacturing errors of vacuum vessel sectors and can be used as a reference for manufacturing of other vacuum vessels.

关键词： CFETR VV Measuring and fitting method Weight factor fitting algorithm

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The cascaded steady-state lumped parameter circuits for describing resonance characteristics of transmission lines

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ELECTRIC POWER SYSTEMS RESEARCH 2025年 241卷

作者： Sun, Xing Lei, Wanjun Hu, Linqiang Zhang, Xiaotong Li, Lei Xi An Jiao Tong Univ Sch Elect Engn State Key Lab Elect Insulat & Power Equipment Xian 710000 Peoples R China

This paper proposes a determination method for cascaded lumped parameter circuits (LPCs) to describe steadystate resonance characteristics of transmission lines, with a focus on the cascaded number. The physical simulation of long-distance transmission lines is achieved by cascaded LPCs. The existing methods for determining the cascaded number are applicable to transient-state operating conditions. The LPC with a cascaded number adequate for transient-state needs causes misjudgment in physical simulation. The number is determined by simulation and is limited by computational simulation software tools. This paper proposes a fitting participation factor (PF)-based method to determine the cascaded number. With the proposed method, the LPC and the transmission line have approximately proportional harmonic propagation distribution and harmonic voltage. Errors of resonance frequency and resonance center in the LPC are investigated based on numerical analysis and resonance mode analysis. The misjudgment in physical simulation is discussed through PF. Next, the general expression for the measuring impedance of the LPC is deducted. The applicable operating conditions and equivalent conditions for various LPCs are examined. In addition, the proposed method is independent of skin effect and suitable for lossy lines. The validity of the proposed method is verified by simulations.

关键词： Transmission lines Lumped parameter circuits Cascaded number Resonance characteristics fitting algorithm

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IDPMS: A New Integrated Dose-Position Measuring System for Ion Therapy

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2025年 74卷

作者： Li, Juan Chen, Yucong Li, Weilong Liu, Xiaotao Xu, Zhiguo Luo, Faming Zhao, Zulong Kang, Xincai Mao, Ruishi Hu, Zhengguo Chinese Acad Sci Inst Modern Phys Lanzhou 730000 Gansu Peoples R China Lanzhou Univ Sch Informat Sci & Engn Lanzhou 730000 Gansu Peoples R China

For proton or carbon ion therapy, when using the point scanning method to control a pencil beam for treatment, rapid measurement of the position of each spot, the absorbed dose, and even the angle of incidence, as well as rapid feedback and interlocking signals, are necessary to ensure the accuracy of beam delivery. In this article, we present a new integrated dose-position measuring system (IDPMS) developed by the Institute of Modern Physics that is highly integrated and scalable, with fast measurement speed and no dead time. The system can rapidly measure the beam position and the relative absorbed dose. Optical ports can also synchronize the two systems to measure beam incidence angularity rapidly. A new Gaussian fitting algorithm has been developed on the field programmable gate array (FPGA) of this system, which has been tested by many beams and operated stably and reliably and can complete the Gaussian fitting within 4 mu s. In point scanning mode, the detector system can achieve a spot position measurement with a maximum deviation of 0.15 mm and generate a beam spot position interlock signal within 55 mu s. Using two ionization chambers (ICs) working in synchronization with a distance of more than 103 mm, the virtual source axis distance of similar to 7 m, the maximum deviation of the elevation angle is 0.03 degrees, and the maximum deviation of the azimuth angle is 1.38 degrees. The system's scalability and multiple modes of operation make it capable of meeting the beam monitoring needs of most current ion therapy devices and achieving machine quality assurance (QA). In addition, the system can also monitor the beam state in real-time in particle physics experiments, providing powerful technical support for scientific research and medical applications.

关键词： Monitoring Medical treatment Detectors Ions Position measurement Particle beam measurements fitting Accuracy Synchronization Particle measurements Beam incidence angle measure fitting algorithm ion therapy ionization chamber (IC) real-time dose-position measure

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An algorithm for fitting Heavy-Tailed Distributions via Generalized Hyperexponentials

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INFORMS JOURNAL ON COMPUTING 2012年第1期24卷 42-52页

作者： Yu, Kaiqi Huang, Mei-Ling Brill, Percy H. Univ Windsor Dept Management Sci Windsor ON N9B 3P4 Canada Univ Windsor Dept Math & Stat Windsor ON N9B 3P4 Canada Brock Univ Dept Math St Catharines ON LS2 3A1 Canada

In this paper, we propose an algorithm to fit heavy-tailed (HT) distribution functions by generalized hyperexponential (GH) distribution functions. A discussion of the steps, usage, and accuracy of the GH algorithm is given. Several examples in this paper show that the proposed method can be applied to fit HT distributions with a completely monotone probability density function (pdf) very well, like the Pareto distribution and the Weibull distribution with the shape parameter less than one, as well as HT distributions whose pdf is not completely monotone, like the lognormal distribution. In addition, we provide an example that shows that the proposed method can be applied to density estimation of real data presenting a heavy tail.

关键词： fitting algorithm heavy-tailed distribution generalized hyperexponential distribution hyperexponential distribution

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An algorithm for the fitting of a tree metric according to a weighted least-squares criterion

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JOURNAL OF CLASSIFICATION 1999年第1期16卷 3-26页

作者： Makarenkov, V Leclerc, B Univ Montreal Dept Sci Biol Montreal PQ H3C 3J7 Canada Ecole Hautes Etud Sci Sociales Ctr Anal & Math Sociales F-75270 Paris 06 France

The fitting of a tree metric to a given dissimilarity with a weighted least-squares criterion is considered. According to several authors, this criterion is well adapted to the problem of inferring evolutionary trees, as, for instance, phylogenies. Because the problem is already known to be NP-hard for the unweighted least-squares formulation, the weighted case would profit from good heuristics. The heuristics proposed in the literature in the unweighted case do not typically generalize to the weighted case, for instance to phylogenetic models incorporating an evolutionary noise which is not proportional to the distance values. We propose an original method for the construction of a tree by stepwise addition, with a calculation of the lengths of the new edges according to a least-squares criterion allowing the introduction of arbitrary weights. This procedure is tested on some examples and compared, on the basis of a classical scheme already used several times in the literature, to classical unweighted methods, and to the weighted methods recently proposed by Gonnet (1994) and by Felsenstein (1997).

关键词： tree metric dissimilarity phylogenetic tree fitting algorithm weighted least squares lagrange multipliers

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Technical Note: In silico and experimental evaluation of two leaf-fitting algorithms for MLC tracking based on exposure error and plan complexity

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MEDICAL PHYSICS 2019年第4期46卷 1814-1820页

作者： Caillet, Vincent O'Brien, Ricky Moore, Douglas Poulsen, Per Pommer, Tobias Colvill, Emma Sawant, Amit Booth, Jeremy Keall, Paul Northern Sydney Canc Ctr Sydney NSW Australia Univ Sydney Sydney Med Sch ACRF Image X Inst Sydney NSW Australia Arizona State Univ Ctr Fundamental Concepts Sci Tempe AZ USA Aarhus Univ Aarhus Denmark Karolinska Univ Hosp Unit Radiotherapy Phys & Engn Solna Sweden Univ Maryland Sch Med Dept Radiat Oncol Baltimore MD 21201 USA

PurposeMultileaf collimator (MLC) tracking is being clinically pioneered to continuously compensate for thoracic and pelvic motion during radiotherapy. The purpose of this work was to characterize the performance of two MLC leaf-fitting algorithms, direct optimization and piecewise optimization, for real-time motion compensation with different plan complexity and tumor trajectories. MethodsTo test the algorithms, both in silico and phantom experiments were performed. The phantom experiments were performed on a Trilogy Varian linac and a HexaMotion programmable motion platform. High and low modulation VMAT plans for lung and prostate cancer cases were used along with eight patient-measured organ-specific trajectories. For both MLC leaf-fitting algorithms, the plans were run with their corresponding patient trajectories. To compare algorithms, the average exposure errors, i.e., the difference in shape between ideal and fitted MLC leaves by the algorithm, plan complexity and system latency of each experiment were calculated. ResultsComparison of exposure errors for the in silico and phantom experiments showed minor differences between the two algorithms. The average exposure errors for in silico experiments with low/high plan complexity were 0.66/0.88cm(2) for direct optimization and 0.66/0.88cm(2) for piecewise optimization, respectively. The average exposure errors for the phantom experiments with low/high plan complexity were 0.73/1.02cm(2) for direct and 0.73/1.02cm(2) for piecewise optimization, respectively. The measured latency for the direct optimization was 22610ms and for the piecewise algorithm was 228 +/- 10ms. In silico and phantom exposure errors quantified for each treatment plan demonstrated that the exposure errors from the high plan complexity (0.96cm(2) mean, 2.88cm(2) 95% percentile) were all significantly different from the low plan complexity (0.70cm(2) mean, 2.18cm(2) 95% percentile) (P<0.001, two-tailed, Mann-Whitney statistical test). Conclusio

关键词： fitting algorithm MLC tracking radiotherapy real-time

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