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Adaptive Fuzzy Logic Despeckling in Non-Subsampled Contourlet Transformed Ultrasound Pictures
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作者 T.Manikandan S.Karthikeyan +1 位作者 J.Jai Jaganath Babu G.Babu 《Intelligent Automation & Soft Computing》 SCIE 2023年第3期2755-2771,共17页
Signal to noise ratio in ultrasound medical images captured through the digital camera is poorer,resulting in an inaccurate diagnosis.As a result,it needs an efficient despeckling method for ultrasound images in clinic... Signal to noise ratio in ultrasound medical images captured through the digital camera is poorer,resulting in an inaccurate diagnosis.As a result,it needs an efficient despeckling method for ultrasound images in clinical practice and tel-emedicine.This article proposes a novel adaptive fuzzyfilter based on the direc-tionality and translation invariant property of the Non-Sub sampled Contour-let Transform(NSCT).Since speckle-noise causes fuzziness in ultrasound images,fuzzy logic may be a straightforward technique to derive the output from the noisy images.Thisfiltering method comprises detection andfiltering stages.First,image regions classify at the detection stage by applying fuzzy inference to the directional difference obtained from the NSCT noisy image.Then,the system adaptively selects the better-suitedfilter for the specific image region,resulting in significant speckle noise suppression and retention of detailed features.The suggested approach uses a weighted averagefilter to distinguish between noise and edges at thefiltering stage.In addition,we apply a structural similarity mea-sure as a tuning parameter depending on the kind of noise in the ultrasound pic-tures.The proposed methodology shows that the proposed fuzzy adaptivefilter effectively suppresses speckle noise while preserving edges and image detailed structures compared to existing approaches. 展开更多
关键词 Image processing fuzzy logic directional differences classification ultrasound technology
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Constructing Pandiagonal Snowflake Magic Squares of Odd Order 被引量:3
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作者 ZHANGShi-de HUQing-wen WANGJi-zhao 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第2期172-185,共14页
The constructional methods of pandiagonal snowflake magic squares of orders 4m are established in paper [3]. In this paper, the constructional methods of pandiagonal snowflake magic squares of odd orders n are establi... The constructional methods of pandiagonal snowflake magic squares of orders 4m are established in paper [3]. In this paper, the constructional methods of pandiagonal snowflake magic squares of odd orders n are established with n = 6m+l, 6m+5 and 6m+3, m is an odd positive integer and m is an even positive integer 9|6m + 3. It is seen that the number sets for constructing pandiagonal snowflake magic squares can be extended to the matrices with symmetric partial difference in each direction for orders 6m + 1 , 6m + 5; to the trisection matrices with symmetric partial difference in each direction for order 6m + 3. 展开更多
关键词 pandiagonal magic squares matrix with uniform partial difference in each direction matrix with symmetric partial difference in each direction trisection matrix with uniform partial difference in each direction semi-pandiagonal Latin square
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Effect of Wave Headings on the Dynamic Response of the Continuous Mating Operation of Floatover Installation 被引量:1
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作者 BAI Xiao-dong LUO Han-bing XIE Peng 《China Ocean Engineering》 SCIE EI CSCD 2021年第1期72-83,共12页
The topside floatover installation is always a great challenge and is sensitive to environmental conditions.In this study,experimental analysis on the mating operation of the floatover installation in different wave h... The topside floatover installation is always a great challenge and is sensitive to environmental conditions.In this study,experimental analysis on the mating operation of the floatover installation in different wave headings is presented.The continuous mating operation using the rapid transfer technique was experimentally simulated with the assistance of the jacking system and the ballast system.In the continuous transfer modeling,the topsides loads were transferred onto the jacket by several consecutive steps,including the first rapid jack-down for the 30%loads,continuous 30%−70%load transfer and the second repaid jack-down for the remaining 30%loads.Motions of the barge and the topsides as well as loads on the Deck Support Unite(DSU)and the Leg Mating Unite(LMU)in different wave headings were measured.Experimental results illustrated the complex motion behavior and load characteristics of the continuous transfer operation.Results indicate that the rapid jack-down operations will lead to impact loads and larger lateral DSU loads.The bow quartering seas are much more dangerous as it gives rise to the larger motions and loads.Comparisons with the traditional steady-state modeling indicate that the continuous transfer modeling has greater advantages over the steady-state modeling on predicting the loads. 展开更多
关键词 floatover installation rapid transfer technique model test different wave directions
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Shape Similarity Measures of Linear Entities 被引量:1
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作者 ZhangQiaopin LIDeren 《Geo-Spatial Information Science》 2002年第2期62-67,共6页
The essential of feature matching technology lies in how to measure the similarity of spatial entities.Among all the possible similarity measures,the shape similarity measure is one of the most important measures beca... The essential of feature matching technology lies in how to measure the similarity of spatial entities.Among all the possible similarity measures,the shape similarity measure is one of the most important measures because it is easy to collect the necessary parameters and it is also well matched with the human intuition.In this paper a new shape similarity measure of linear entities based on the differences of direction change along each line is presented and its effectiveness is illustrated. 展开更多
关键词 feature matching similarity measures of spatial entities shape analysis differences of direction change
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Distributed adaptive direct position determination based on diffusion framework 被引量:2
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作者 Wei Xia Wei Liu Lingfeng Zhu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第1期28-38,共11页
The conventional direct position determination(DPD) algorithm processes all received signals on a single sensor.When sensors have limited computational capabilities or energy storage,it is desirable to distribute th... The conventional direct position determination(DPD) algorithm processes all received signals on a single sensor.When sensors have limited computational capabilities or energy storage,it is desirable to distribute the computation among other sensors.A distributed adaptive DPD(DADPD)algorithm based on diffusion framework is proposed for emitter localization.Unlike the corresponding centralized adaptive DPD(CADPD) algorithm,all but one sensor in the proposed algorithm participate in processing the received signals and estimating the common emitter position,respectively.The computational load and energy consumption on a single sensor in the CADPD algorithm is distributed among other computing sensors in a balanced manner.Exactly the same iterative localization algorithm is carried out in each computing sensor,respectively,and the algorithm in each computing sensor exhibits quite similar convergence behavior.The difference of the localization and tracking performance between the proposed distributed algorithm and the corresponding CADPD algorithm is negligible through simulation evaluations. 展开更多
关键词 emitter localization time difference of arrival(TDOA) direct position determination(DPD) distributed adaptive DPD(DADPD) diffusion framework.
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Removing Random-Valued Impulse Noises by a Two-Staged Nonlinear Filtering Method
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作者 Ahmad Ashfaq Lu Yanting 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2016年第3期329-338,共10页
Digital images are frequently contaminated by impulse noise(IN)during acquisition and transmission.The removal of this noise from images is essential for their further processing.In this paper,a two-staged nonlinear f... Digital images are frequently contaminated by impulse noise(IN)during acquisition and transmission.The removal of this noise from images is essential for their further processing.In this paper,a two-staged nonlinear filtering algorithm is proposed for removing random-valued impulse noise(RVIN)from digital images.Noisy pixels are identified and corrected in two cascaded stages.The statistics of two subsets of nearest neighbors are employed as the criterion for detecting noisy pixels in the first stage,while directional differences are adopted as the detector criterion in the second stage.The respective adaptive median values are taken as the replacement values for noisy pixels in each stage.The performance of the proposed method was compared with that of several existing methods.The experimental results show that the performance of the suggested algorithm is superior to those of the compared methods in terms of noise removal,edge preservation,and processing time. 展开更多
关键词 image de-noising random-valued impulse noise nonlinear filter noisy pixel detection two-stage detection and correction method cascaded stages directional differences
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Establishment and Application of A Mathematical Model for Rectangular Billet Continuos Casting
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作者 IJU Qing TIAN Nianyuan +5 位作者 WANG Yingqun WU Xiaodong HOU Wenyi XU Mingxin XIANYU Jintang ZHANG Xiumu(Shanghai Pudong Iron & Steel Co. Ltd.)(Metallurgy Engineering School, USTB, Beijiing 100083, China) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1997年第4期10-14,共5页
A two dimension unsteady heat transfer model is established for rectangular billet casting. Solidification process of liquid steel in secondary cooling zone was analyzed using direct difference method. The influence o... A two dimension unsteady heat transfer model is established for rectangular billet casting. Solidification process of liquid steel in secondary cooling zone was analyzed using direct difference method. The influence of operation parameters including casting speed and temperature of liquid steel was investigated. Experimental results have been used for increasing the casting speed. 展开更多
关键词 continuous casting rectangular billed direct difference method mathematical model
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Amplitude variation characteristics of active source airgun signals at Qilian Mountain
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作者 Xuzhou Liu Yuansheng Zhang +3 位作者 Zhiguo Liu Manzhong Qin Rui Zou Xiao Guo 《Earthquake Science》 2021年第2期161-167,共7页
In this study,Qilian Mountain active source airgun signals recorded at 79 stations were obtained after stacking waveforms from July 2015 to December 2016.Based on analysis of the amplitude variation characteristics of... In this study,Qilian Mountain active source airgun signals recorded at 79 stations were obtained after stacking waveforms from July 2015 to December 2016.Based on analysis of the amplitude variation characteristics of the airgun signals,the following conclusions were drawn:along the NW-SE fault distribution direction of the Qilian Mountain area,the decrease in amplitude of airgun signals was relatively slow in relation to the epicentral distance,while the decrease in amplitude in the direction perpendicular to the fault was relatively fast.This difference may be related to the energy loss of seismic waves reflecting and scattering by the regional faults mainly distributed along the NW-SE direction,which are caused by tectonic compression of the QinghaiTibet and Alxa blocks. 展开更多
关键词 airgun signal amplitude variation seismic wave directional difference Qilian Mountain.
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Reliable approach for bistatic scattering of three-dimensional targets from underlying rough surface based on parabolic equation
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作者 Dong-Min Zhang Cheng Liao +2 位作者 Liang Zhou Xiao-Chuan Deng Ju Feng 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第7期314-320,共7页
A parabolic equation (PE) based method for analyzing composite scattering under an electromagnetic wave incidence at low grazing angle, which composes of three-dimensional (3-D) electrically large targets and roug... A parabolic equation (PE) based method for analyzing composite scattering under an electromagnetic wave incidence at low grazing angle, which composes of three-dimensional (3-D) electrically large targets and rough surface, is presented and discussed. A superior high-order PE version is used to improve the accuracy at wider paraxial angles, and along with the alternating direction implicit (ADI) differential technique, the computational efficiency is further improved. The formula of bistatic normalized radar cross section is derived by definition and near-far field transformation. Numerical examples are given to show the validity and accuracy of the proposed approach, in which the results are compared with those of Kirchhoff approximation (KA) and moment of method (MoM). Furthermore, the bistatic scattering properties of composite model in which the 3-D PEC targets on or above the two-dimensional Gaussian rough surfaces under the tapered wave incidence are analyzed. 展开更多
关键词 parabolic equation rough surface alternating direction implicit (ADI) difference normalizedradar cross section
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Stability and convergence of the variable directions difference scheme for one nonlinear two-dimensional model 被引量:1
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作者 Temur Jangveladze Zurab Kiguradze +1 位作者 Mikheil Gagoshidze Maia Nikolishvili 《International Journal of Biomathematics》 2015年第5期31-51,共21页
The system of two-dimensional nonlinear partial differential equations is considered. This system describes the vein formation in meristematic tissues of young leaves. Variable directions difference scheme is construc... The system of two-dimensional nonlinear partial differential equations is considered. This system describes the vein formation in meristematic tissues of young leaves. Variable directions difference scheme is constructed and investigated. Absolute stability regarding space and time steps of scheme is shown. The convergence statement for the constructed scheme is proved. Rate of convergence is given. Various numerical experiments are carried out and results of some of them are considered in this paper. Comparison of numerical experiments with the results of the theoretical investigation is given too. 展开更多
关键词 Variable directions difference scheme nonlinear partial differential equations stability CONVERGENCE vein formation.
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Between“Guandai”(冠带)and“Yidi”(夷狄):Sima Qian's National Consciousness
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作者 Zijin WANG Ruli WANG 《Journal of the Chinese Nation Studies》 2023年第1期151-176,共26页
During the reign of Emperor Wu of Han Dynasty,the ethnic relations in China entered a new historical stage.Records of the Historian written during this period gives a basically factual account of the ethnic history in... During the reign of Emperor Wu of Han Dynasty,the ethnic relations in China entered a new historical stage.Records of the Historian written during this period gives a basically factual account of the ethnic history in China since ancient epochs.It is the first specialized work on ethnic history.The national consciousness that Sima Qian presents in this work is distinctively different from the Confucian tradition,which draws a strict line between Hua(华,China)and Yi(夷,the barbarians).His attention on the commonality of the cultural genes between the farming peoples of the Central-Plains and the nomadic hunting peoples of the borderlands,his recognition of the integrated impact that multiple ethnic groups have on the rise and development of Huaxia(华夏,Chinese)civilization,his respect for"differences among barbarians of the four directions"(四夷各异),and his approval of the“merits of Hu attire”(胡服之功)are all embodiment of his liberal views.To explore the formation and development of the cultural community of the Chinese nation and to understand and interpret this historical process of ethnic integration,we should attach great importance to the positive significance of Sima Qian's national consciousness. 展开更多
关键词 Records of the Historian Guandai Yidi cultural genes the merits of Hu attire Li Ling differences among barbarians of the four directions
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DISCRETE MAXIMUM PRINCIPLE AND CONVERGENCE OF POISSON PROBLEM FOR THE FINITE POINT METHOD 被引量:1
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作者 Guixia Lv Shunkai Sun Longjun Shen 《Journal of Computational Mathematics》 SCIE CSCD 2017年第3期245-264,共20页
This paper makes some mathematical analyses for the finite point method based on directional difference. By virtue of the explicit expressions of numerical formulae using only five neighboring points for computing fir... This paper makes some mathematical analyses for the finite point method based on directional difference. By virtue of the explicit expressions of numerical formulae using only five neighboring points for computing first-order and second-order directional differ- entials, a new methodology is presented to discretize the Laplacian operator defined on 2D scattered point distributions. Some sufficient conditions with very weak limitations are obtained, under which the resulted schemes are positive schemes. As a consequence, the discrete maximum principle is proved, and the first order convergent result of O(h) is achieved for the nodal solutions defined on scattered point distributions, which can be raised up to O(h2) on uniform point distributions. 展开更多
关键词 Finite point method Directional difference MESHLESS Discrete maximum prin-ciple Convergence analysis.
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The Spectrum of (gv, g, 3, λ)-dDF in Z_(gv)
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作者 Xiao Miao WANG Yan Xun CHANG 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2010年第2期377-392,共16页
In this paper, several recursive constructions for directed difference family and perfect directed difference family are presented by means of difference matrix and incomplete difference matrix. Finally the necessary ... In this paper, several recursive constructions for directed difference family and perfect directed difference family are presented by means of difference matrix and incomplete difference matrix. Finally the necessary and sufficient conditions for the existence of a (gv, g, 3, λ)-directed difference family in Zgv are established. As a consequence, the necessary and sufficient conditions for the existence of a cyclic directed group divisible design with block size three and type gv are obtained. 展开更多
关键词 directed difference family incomplete difference matrix perfect directed difference family
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