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自适应分数阶微分在图像纹理增强中的应用 被引量:41
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作者 汪成亮 兰利彬 周尚波 《重庆大学学报(自然科学版)》 EI CAS CSCD 北大核心 2011年第2期32-37,共6页
针对目前只能通过人为实验指定最佳分数阶微分阶数的现状,为了节省大量人工寻求最佳分数阶微分阶数的时间,研究并提出了可以依据掩模窗口大小、G-L公式、图像梯度特征和人眼视觉特性等理论的能够自动生成分数阶微分阶数的新方法,基于该... 针对目前只能通过人为实验指定最佳分数阶微分阶数的现状,为了节省大量人工寻求最佳分数阶微分阶数的时间,研究并提出了可以依据掩模窗口大小、G-L公式、图像梯度特征和人眼视觉特性等理论的能够自动生成分数阶微分阶数的新方法,基于该自适应阶数,设计并实现了对应的算子掩模。采用了信息熵、平均梯度等图像纹理特征评价参数做定量分析和实验验证,结果表明,该方法对任意灰度图像可以得到连续变化的增强效果,接近于最佳分数阶微分增强效果,符合人们的视觉感受,是有效的图像纹理增强方法。 展开更多
关键词 分数阶微分阶数 掩模 梯度方法 视觉特性 图像纹理增强
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Design of a fractional PI~λD~μ controller using the cohort intelligence method 被引量:1
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作者 Pritesh SHAH Sudhir AGASHE Anand J.KULKARNI 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2018年第3期437-445,共9页
The cohort intelligence (CI) method has recently evolved as an optimization method based on artificial intelligence. We use the CI method for the first time to optimize the parameters of the fractional proportional-... The cohort intelligence (CI) method has recently evolved as an optimization method based on artificial intelligence. We use the CI method for the first time to optimize the parameters of the fractional proportional- integral-derivative (PID) controller. The performance of the CI method in designing the fractional PID controller was validated and compared with those of some other popular algorithms such as particle swarm optimization, the genetic algorithm, and the improved electromagnetic algorithm. The CI method yielded improved solutions in terms of the cost function, computing time, and function evaluations in comparison with the other three algorithms. In addition, the standard deviations of the CI method demonstrated the robustness of the proposed algorithm in solving control problems. 展开更多
关键词 Cohort intelligence Fractional calculus Fractional PID controller Tuning
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Exact solutions of some fractional differential equations arising in mathematical biology
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作者 Ozkan Guner Ahmet Bekir 《International Journal of Biomathematics》 2015年第1期29-45,共17页
In the last decades Exp-function method has been used for solving fractional differential equations. In this paper, we obtain exact solutions of fractional generalized reaction Duff- ing model and nonlinear fractional... In the last decades Exp-function method has been used for solving fractional differential equations. In this paper, we obtain exact solutions of fractional generalized reaction Duff- ing model and nonlinear fractional diffusion-reaction equation. The fractional derivatives are described in the modified Riemann-Liouville sense. The fractional complex trans- form has been suggested to convert fractional-order differential equations with modified Riemann-Liouville derivatives into integer-order differential equations, and the reduced equations can be solved by symbolic computation. 展开更多
关键词 Fractional partial differential equation exact solutions Exp-function method modified Riemann-Liouville derivative.
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