To overcome the shortcomings of the Lee image enhancement algorithm and its improvement based on the logarithmic image processing(LIP) model, this paper proposes what we believe to be an effective image enhancement al...To overcome the shortcomings of the Lee image enhancement algorithm and its improvement based on the logarithmic image processing(LIP) model, this paper proposes what we believe to be an effective image enhancement algorithm. This algorithm introduces fuzzy entropy, makes full use of neighborhood information, fuzzy information and human visual characteristics.To enhance an image, this paper first carries out the reasonable fuzzy-3 partition of its histogram into the dark region, intermediate region and bright region. It then extracts the statistical characteristics of the three regions and adaptively selects the parameter αaccording to the statistical characteristics of the image’s gray-scale values. It also adds a useful nonlinear transform, thus increasing the ubiquity of the algorithm. Finally, the causes for the gray-scale value overcorrection that occurs in the traditional image enhancement algorithms are analyzed and their solutions are proposed.The simulation results show that our image enhancement algorithm can effectively suppress the noise of an image, enhance its contrast and visual effect, sharpen its edge and adjust its dynamic range.展开更多
In this article a new achievement of fractional-order 3×n Fan networks is presented.In the first step,the RT-I method is used to derive the general formulae of the equivalent impedance of fractional-order 3×...In this article a new achievement of fractional-order 3×n Fan networks is presented.In the first step,the RT-I method is used to derive the general formulae of the equivalent impedance of fractional-order 3×n Fan networks.In the second part,the effects of five system parameters(L,C,n,α and β)on amplitude-frequency and phase-frequency characteristics are analyzed.At the same time,the amplitude-frequency and phase-frequency characteristics of the fractional order 3×n Fan network are revealed by Matlab drawing.This work has important theoretical and practical significance for resistor network models in the field of natural science and engineering technology.展开更多
As a critical structure of aerospace equipment,aluminum alloy stiffened plate will influence the stability of spacecraft in orbit and the normal operation of the system.In this study,a GWO-ELM algorithm-based impact d...As a critical structure of aerospace equipment,aluminum alloy stiffened plate will influence the stability of spacecraft in orbit and the normal operation of the system.In this study,a GWO-ELM algorithm-based impact damage identification method is proposed for aluminum alloy stiffened panels to monitor and evaluate the damage condition of such stiffened panels of spacecraft.Firstly,together with numerical simulation,the experimental simulation to obtain the damage acoustic emission signals of aluminum alloy reinforced panels is performed,to establish the damage data.Subsequently,the amplitude-frequency characteristics of impact damage signals are extracted and put into an extreme learning machine(ELM)model to identify the impact location and damage degree,and the Gray Wolf Optimization(GWO)algorithm is employed to update the weight parameters of the model.Finally,experiments are conducted on the irregular aluminum alloy stiffened plate with the size of 2200 mm×500 mm×10 mm,the identification accuracy of impact position and damage degree is 98.90% and 99.55% in 68 test areas,respectively.Comparative experiments with ELM and backpropagation neural networks(BPNN)demonstrate that the impact damage identification of aluminum alloy stiffened plate based on GWO-ELM algorithm can serve as an effective way to monitor spacecraft structural damage.展开更多
通过耕地流转实现农业适度规模经营,是解决"谁来种田"的关键。分析各因素对耕地流转的作用及影响强度,识别其主导因素,对促进耕地适度规模经营具有积极意义。该文运用对数平均迪氏分解方法(logarithmic mean weigh Division i...通过耕地流转实现农业适度规模经营,是解决"谁来种田"的关键。分析各因素对耕地流转的作用及影响强度,识别其主导因素,对促进耕地适度规模经营具有积极意义。该文运用对数平均迪氏分解方法(logarithmic mean weigh Division index method,LMDI)建立因素分解模型,定量评价并对比分析2008?2014年间中国省域耕地流转变动的驱动因素。研究结果表明,1)2008?2014年,中国耕地流转面积累计增长了1.96?107 hm2,增长2.7倍,年均增长率达到24.40%,京津地区、黄淮海地区、长江中下游地区、东北地区等经济活跃或优势农业产区的耕地流转发展较快。2)经济因素、农民增收因素、农机化因素对耕地流转有显著的正向作用,其中农机化因素对耕地流转的促进作用最大,研究期内农机化累计效应促进耕地流转率提高18.16%,经营意愿因素对耕地流转有显著的负向影响。3)区域之间4个分解因素的累计效应存在显著差异。总体而言,经济效应促进了华东与华南地区耕地流转率的显著提高,农民增收效应主要促进了华东地区耕地流转率提高,农机化效应促进了大部分地区耕地流转率提高10%以上,但华南与西南地区相对较低。展开更多
基金supported by the National Natural Science Foundation of China(61472324)
文摘To overcome the shortcomings of the Lee image enhancement algorithm and its improvement based on the logarithmic image processing(LIP) model, this paper proposes what we believe to be an effective image enhancement algorithm. This algorithm introduces fuzzy entropy, makes full use of neighborhood information, fuzzy information and human visual characteristics.To enhance an image, this paper first carries out the reasonable fuzzy-3 partition of its histogram into the dark region, intermediate region and bright region. It then extracts the statistical characteristics of the three regions and adaptively selects the parameter αaccording to the statistical characteristics of the image’s gray-scale values. It also adds a useful nonlinear transform, thus increasing the ubiquity of the algorithm. Finally, the causes for the gray-scale value overcorrection that occurs in the traditional image enhancement algorithms are analyzed and their solutions are proposed.The simulation results show that our image enhancement algorithm can effectively suppress the noise of an image, enhance its contrast and visual effect, sharpen its edge and adjust its dynamic range.
基金supported by the National Training Programs of Innovation and Entrepreneurship for Undergraduates(Grant No.202210304006Z).
文摘In this article a new achievement of fractional-order 3×n Fan networks is presented.In the first step,the RT-I method is used to derive the general formulae of the equivalent impedance of fractional-order 3×n Fan networks.In the second part,the effects of five system parameters(L,C,n,α and β)on amplitude-frequency and phase-frequency characteristics are analyzed.At the same time,the amplitude-frequency and phase-frequency characteristics of the fractional order 3×n Fan network are revealed by Matlab drawing.This work has important theoretical and practical significance for resistor network models in the field of natural science and engineering technology.
基金supported by National Key Research and Development Project(2020YFE0204900)National Natural Science Foundation of China(Grant Nos.61903224,62073193,61873333)Key Research and Development Plan of Shandong Province(Grant Nos.2019TSLH0301,2021CXGC010204).
文摘As a critical structure of aerospace equipment,aluminum alloy stiffened plate will influence the stability of spacecraft in orbit and the normal operation of the system.In this study,a GWO-ELM algorithm-based impact damage identification method is proposed for aluminum alloy stiffened panels to monitor and evaluate the damage condition of such stiffened panels of spacecraft.Firstly,together with numerical simulation,the experimental simulation to obtain the damage acoustic emission signals of aluminum alloy reinforced panels is performed,to establish the damage data.Subsequently,the amplitude-frequency characteristics of impact damage signals are extracted and put into an extreme learning machine(ELM)model to identify the impact location and damage degree,and the Gray Wolf Optimization(GWO)algorithm is employed to update the weight parameters of the model.Finally,experiments are conducted on the irregular aluminum alloy stiffened plate with the size of 2200 mm×500 mm×10 mm,the identification accuracy of impact position and damage degree is 98.90% and 99.55% in 68 test areas,respectively.Comparative experiments with ELM and backpropagation neural networks(BPNN)demonstrate that the impact damage identification of aluminum alloy stiffened plate based on GWO-ELM algorithm can serve as an effective way to monitor spacecraft structural damage.
文摘通过耕地流转实现农业适度规模经营,是解决"谁来种田"的关键。分析各因素对耕地流转的作用及影响强度,识别其主导因素,对促进耕地适度规模经营具有积极意义。该文运用对数平均迪氏分解方法(logarithmic mean weigh Division index method,LMDI)建立因素分解模型,定量评价并对比分析2008?2014年间中国省域耕地流转变动的驱动因素。研究结果表明,1)2008?2014年,中国耕地流转面积累计增长了1.96?107 hm2,增长2.7倍,年均增长率达到24.40%,京津地区、黄淮海地区、长江中下游地区、东北地区等经济活跃或优势农业产区的耕地流转发展较快。2)经济因素、农民增收因素、农机化因素对耕地流转有显著的正向作用,其中农机化因素对耕地流转的促进作用最大,研究期内农机化累计效应促进耕地流转率提高18.16%,经营意愿因素对耕地流转有显著的负向影响。3)区域之间4个分解因素的累计效应存在显著差异。总体而言,经济效应促进了华东与华南地区耕地流转率的显著提高,农民增收效应主要促进了华东地区耕地流转率提高,农机化效应促进了大部分地区耕地流转率提高10%以上,但华南与西南地区相对较低。
