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Simplified analytic solutions and a novel fast algorithm for Yb³⁺-doped double-clad fiber lasers

OPTICS COMMUNICATIONS 2007年第1期277卷 118-124页

作者： Luo, Zhengqian Ye, Chenchun Sun, Guoyong Cai, Zhiping Si, Miaoling Li, Qibo Xiamen Univ Dept Elect Engn Xiamen 361005 Peoples R China

In this paper, continuous wave Yb3+-doped double-clad fiber lasers (DCFLs) with linear-cavity are investigated theoretically and numerically using the rate equations. Under the steady state conditions, the simplified analytic solutions of Yb3+-doped DCFLs under considering the scattering loss are deduced in the strongly pump condition. Compared with the known analytic solutions in published literatures, our analytic solutions are more accurate, especially, at higher reflectivity of output mirror. In addition, a fast and stable algorithm based on the Newton-Raphson method is proposed to simulate numerically Yb3+-doped DCFLs. The results by simplified analytic solutions are in good agreement with those by the numerical simulation. Moreover, we have performed the optimization of an Yb3+-doped DCFL using the simplified analytic Solutions and the numerical simulations, respectively. (c) 2007 Elsevier B.V. All rights reserved.

关键词： double-clad fiber lasers simplified analytic solutions fast algorithm numerical simulation

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Analysis of electromagnetic non-destructive evaluation modelling using Stratton-Chu formulation-based fast algorithm

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PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 2020年第2182期378卷 20190583-20190583页

作者： Bao, Yang Song, Jiming Nanjing Univ Posts & Telecommun Coll Elect & Opt Engn Nanjing 210023 Jiangsu Peoples R China Southeast Univ State Key Lab Millimeter Waves Nanjing 210096 Jiangsu Peoples R China Iowa State Univ Dept Elect & Comp Engn Ames IA 50011 USA Iowa State Univ Ctr Nondestruct Evaluat Ames IA 50011 USA

The eddy current non-destructive evaluation (NDE) modelling using Stratton-Chu formulation-based fast algorithm is analysed. Stratton-Chu formulations, which have no low frequency breakdown issue, are selected for modelling electromagnetic NDE problems with low frequency and high conductivity approximations. As the main contribution of this article, the robustness and efficiency of the approximations, which result in big savings in both memory and CPU time, are validated and analysed using examples from practical EC testing. The boundary element method (BEM) is used to discretize the integral equations into a linear system of equations: the first order Rao-Wilton-Glisson (RWG) vector basis functions with the flat triangle meshes of the object and pulse basis functions are selected to expand the equivalent surface currents and the normal component of magnetic fields, respectively. Then the multilevel adaptive cross approximation (MLACA) algorithm is applied to accelerate the iterative solution process. The performance and efficiency of adaptively applying a multi-stage (level) algorithm based on the criteria concluded for the operators are shown. This article is part of the theme issue 'Advanced electromagnetic non-destructive evaluation and smart monitoring'.

关键词： electromagnetic non-destructive evaluation eddy current testing Stratton-Chu formulations with approximations fast algorithm

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fast algorithm for Rotation and Translation Two-Dimensional Computed Tomography Accurate Reconstruction

Fast Algorithm for Rotation and Translation Two-Dimensional ...

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2010 Symposium on Security Detection and Information Processing

作者： Zhao, Fei Xie, Liyang Wu, Ningxiang Northeasten Univ Shenyang 110004 Peoples R China

RT (rotation and translation) scan mode for 2D (two-dimensional) CT (computed tomography), based on multiple axes, can scan large-sized work pieces and components with paraxial X-ray beam. Compared with the traditional second generation scan mode of TR (translation and rotation), it can save about 3/4 times of the scan time. The accurate reconstruction algorithm by region, can remove the artifacts around inner and outer borders in general reconstruction images. But a mass of zero values participate back-projection operations, and slow down the accurate algorithm operation. In this paper, projection data are grouped according to the regions they located before being back-projected. Data are selected or not according to the regions ID determined in advance during back-projection. So zero values are kicked out by their locations, before doing some time-consuming works such as reading, judging or accumulating the values and so on. And computer simulations show that the reconstruction algorithm saves at least half of the operation time according to the number of rotation centers. (C) 2010 Published by Elsevier Ltd.

关键词： industrial CT RT scan mode large-sized work pieces accurate reconstruction fast algorithm

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fast algorithm on Parameter Estimation of Wideband LFM Signal Based on Down-chirp and CS

Fast Algorithm on Parameter Estimation of Wideband LFM Signa...

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IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC)

作者： Wang Kang Ye Wei Lao Guochao Wang Yong Equipment Acad Beijing Peoples R China

ISBN: (纸本)9781479952748

Compressed Sensing (CS) has been successfully applied to the parameter estimation of Linear Frequency Modulation (LFM) signal. Compared to the Nyquist sampling method, far less samples are needed to estimate the frequency parameter. However, the super-resolution estimation of frequency parameter can greatly increase the number of atoms in the over-complete dictionary and it will brings a huge amount of computation. This paper proposes resolutions to this problem. Taking the feature of CS into account that the sampling and compression are completed at the same time, we structure a measurement matrix which can complete the compressive sampling and down-chirp simultaneously. Furthermore, we propose a down-chirp based method and improve it with fast computing strategy to solve the above problem. Simulation results have proved that the frequency parameter can be accurate estimated under a low SNR and sampling condition. Meanwhile, compared with the proposed method, the improved algorithm greatly reduces the scale of over-complete dictionary and the amount of computation, and the estimation time has been cut down significantly.

关键词： Compressed Sensing parameter estimation LFM fast algorithm down-chirp

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fast algorithm for Evaluation of Critical Parameters of Smart Overalls 11

Fast Algorithm for Evaluation of Critical Parameters of Smar...

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ELEKTRO 11th International Conference

作者： Pavlicek, Karel Kotlan, Vaclav Mach, Frantisek Karban, Pavel Dolezel, Ivo Soukup, Radek Kalcik, Jan Univ West Bohemia Pilsen Plzen Czech Republic

ISBN: (纸本)9781467386982

A fast and efficient algorithm is presented allowing a firefighter dressed in a smart firefighter protective suit continuously informing him about the time that he can still safely spend in a burning bidding, which is characterized by an dynamic environment of time-variable temperature. The algorithm starts from precalculated time evolution of temperature at selected places of the overall (mostly along its internal surface) for a number of values of the delivered external heat power that are then approximated by simple exponential functions. The prediction is then based on successive measurements of three or more temperatures in time and finding such a precalculated exponential function that best tits them. This function is important for predicting the maximum time of stay that is still safe for the firefighter in the current conditions.

关键词： smart protective suit fast algorithm forward problem inverse problem numerical analysis

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fast algorithm BASED ON SOLE-AND MULTI-DEPTH MEASUREMENTS FOR HEVC INTRA CODING 23

FAST ALGORITHM BASED ON SOLE-AND MULTI-DEPTH MEASUREMENTS FO...

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23rd IEEE International Conference on Image Processing (ICIP)

作者： He, Gang Hu, Jing Li, Yunsong Yu, Wenxin Xidian Univ Xian Shaanxi Peoples R China Southwest Univ Sci & Technol Mianyang Sichuan Peoples R China

ISBN: (纸本)9781467399616

In High Efficiency Video Coding (HEVC), intra coding plays an important role, but also involves huge computational complexity due to a flexible coding unit (CU) structure and a large number of prediction modes. This paper presents a fast algorithm based on the sole-and multi-depth measurements to reduce the complexity from CU and prediction mode decisions. For the CU decision, evaluation results with sole and multiple depths are utilized to judge if the CU is a heterogeneous, homogeneous, or depth prominent one, where fast CU decisions are made. For the prediction mode decision, the tendencies for different CU sizes are detected based on multiple depths. The number of searching modes is decreased adaptively for the depth with fewer tendencies. Experimental results show the proposed algorithm reduces 61.49% computational complexity, with 0.75% bit-rate increasing, which is more efficient than state-of-the-arts.

关键词： HEVC fast algorithm intra prediction

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A fast algorithm for joint DC and channel estimation in GSM/EDGE receivers

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2008年第1期62卷 57-62页

作者： Yang, Bin Krueger, Martin Univ Stuttgart D-70550 Stuttgart Germany Infineon Technol AG D-81669 Munich Germany

This paper presents a fast algorithm for the joint least squares DC and channel estimation in GSM/EDGE receivers. In comparison to a straightforward implementation, our algorithm reduces both the computational complex... 详细信息

关键词： GSM and EDGE joint DC and channel estimation least squares fast algorithm

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A fast algorithm of bitstream extraction using distortion prediction based on simulated annealing

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2013年第7期24卷 752-759页

作者： Yang, Kaifang Wan, Shuai Gong, Yanchao Feng, Yan Northwestern Polytech Univ Sch Elect & Informat Xian 710072 Peoples R China

Scalable video streams can be extracted to meet the bandwidth limitation of different networks and end-users. Bitstream extraction is usually performed at the network proxy or gateway during transmission, where a low computational complexity is always preferred. How to quickly and accurately select the best resolution combination for a video to meet different bandwidth requirements by each user is crucial in bitstream extraction. In this paper a fast algorithm of bitstream extraction for scalable video is proposed. The interlayer dependency between the base quality layer and the first quality layer was used to predict the distortion of higher quality layers. When quality of every layer is available, the proposed method searches for the optimized combination of quality layers based on simulated annealing. Experimental results show that the proposed method provides an optimized performance, which is significantly higher than that can be achieved by the basic extraction method. Compared to the quality layer based extraction method in the reference software model of H.264/SVC (i.e., JSVM), the proposed algorithm can greatly decrease the decoding times from 2NT to only 2 without losing rate-distortion performance. Furthermore, the proposed method obtains a more smoothed video quality which is always favorable to the observer. (C) 2013 Elsevier Inc. All rights reserved.

关键词： Scalable Video Coding (SVC) Bitstream extraction Simulated annealing Medium-grain Quality Scalability (MGS) Inter layer dependency Optimization Decoding times fast algorithm

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A fast algorithm for the measurement of stimulus frequency otoacoustic emission suppression tuning curves

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APPLIED ACOUSTICS 2018年第Jan.期129卷 173-180页

作者： Xing, Dongjia Gong, Qin Tsinghua Univ Sch Med Dept Biomed Engn Beijing 100084 Peoples R China Tsinghua Univ Res Ctr Biomed Engn Grad Sch Shenzhen Shenzhen 518055 Guangdong Peoples R China

Frequency selectivity is an important indicator of auditory function in the human ear. Stimulus frequency otoacoustic emission (SFOAE) suppression tuning curves (STCs) have great potential in the objective analysis of human auditory frequency selectivity but are costly to measure by the traditional algorithm using pure-tone adaptive method. To improve the measurement efficiency of the SFOAE STCs, a faster algorithm based on a suppressor with gradiently changing intensity and interpolation is proposed in this paper. Twelve subjects participated in this study by measuring their SFOAE STCs through the traditional and fast algorithm. The results shows that the average correlation coefficients of the SFOAE STCs measured using the fast and the traditional algorithms at different probe frequencies is 0.94. And the measurement speed of the fast algorithm was approximately 2.10 times higher than the traditional one. Also, the fast algorithm is more efficient than the algorithms of Keefe et al. (2008) and Charaziak et al. (2013). Experimental evidence is provided that the proposed fast algorithm greatly improves the measurement speed and reduces the processing time, exhibiting good accuracy and reliability. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Stimulus frequency otoacoustic emission Suppression tuning curves fast algorithm

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A fast algorithm for solving diagonally dominant symmetric pentadiagonal Toeplitz systems

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2010年第4期234卷 995-1005页

作者： McNally, Jeffrey Mark St Francis Xavier Univ Dept Math Stat & Comp Sci Antigonish NS B2G 2W5 Canada

Banded Toeplitz systems of linear equations arise in many application areas and have been well studied in the past. Recently, significant advancement has been made in algorithm development of fast parallel scalable methods to solve tridiagonal Toeplitz problems. In this paper we will derive a new algorithm for solving symmetric pentadiagonal Toeplitz systems of linear equations based upon a technique used in [J.M. McNally, L.E. Garey, R.E. Shaw, A split-correct parallel algorithm for solving tri-diagonal symmetric Toeplitz systems, Int. J. Comput. Math. 75 (2000) 303-313] for tridiagonal Toeplitz systems. A common example which arises in natural quintic spline problems will be used to demonstrate the algorithm's effectiveness. Finally computational results and comparisons will be presented. (C) 2009 Elsevier B.V. All rights reserved.

关键词： Toeplitz Pentadiagonal Linear systems fast algorithm Perturbation analysis Natural quintic splines

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