- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A Novel Plant Propagation-Based Cascaded Fractional Order PI Controller for Optimal Operation of Grid-Connected Single-Stage Three-Phase Solar Photovoltaic System
摘要： Grid-connected photovoltaic (PV) inverters are gaining attention all over the world. The optimal controller setting is key to the successful operation of a grid-connected PV system. In this paper, a novel plant propagation algorithm-based fractional order proportional-integrator (FOPI) controller for cascaded DC link voltage and inner current control of a grid-connected PV controller has been proposed, which outperforms particle swarm optimization-based PI and elephant herding optimization-based FOPI in terms of multicriteria-based analysis. The performance of the proposed controller also has been measured in terms of total harmonic distortion to maintain the appropriate power quality. Also, the proposed controllers were tested under various solar irradiance and voltage sag conditions to show the effectiveness and robustness of the controllers. The whole system is developed in OPAL-RT using MATLAB/Simulink and RT-LAB as a machine-in-loop (MIL) system to validate the performance in real time.
关键词： DC link voltage controller,inner current controller,elephant herding optimization,plant propagation algorithm,grid-connected PV,particle swarm optimization,fractional order PI controller
更新于2025-09-16 10:30:52
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Simultaneous image fusion and denoising by using fractional-order gradient information
摘要： Image fusion and denoising are significant in image processing because of the availability of multi-sensor and the presence of the noise. The first-order and second-order gradient information have been effectively applied to deal with fusing the noise-free source images. In this paper, we utilize the fractional-order derivatives to represent image features, and propose two new convex variational models for fusing noisy source images. Furthermore, we apply an alternating direction method of multiplier (ADMM) to solve the minimization problems in the proposed models. Numerical experiments show that the proposed methods outperform the conventional total variation methods for simultaneously fusing and denoising.
关键词： fractional-order derivative,structure tensor,alternating direction method of multiplier,image fusion and denoising,inverse problem
更新于2025-09-10 09:29:36
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - A Fractional Active Contour Model for Medical Image Segmentation
摘要： Consideration of both traditional local and global information segmentation remains a image challenging task. Some hybrid methods have shown promise in handling this challenge. In this paper, a new hybrid method is presented, which incorporates image gradient, local information and global information into a framework. The energy or level-set function fractional order fractional order gradient magnitude, and differentiation, local difference Chan-Vese model, which has been shown to be effective and efficient in modeling the local information. The presented new model can also enhance low frequency information, which is clinically desired. Experiments on synthetic images as well as real images were performed to demonstrate the segmentation accuracy and computational efficiency of the presented hybrid method. The dice similarity coefficient merit was employed as the comparative quantitative measures and showed a noticeable gain over a current hybrid method.
关键词： Fractional order differentiation,Level set,Active contour model,Image segmentation
更新于2025-09-09 09:28:46
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X-ray structural analysis of an epitaxially grown Ag film/Si(111)$\sqrt{3} \times \sqrt{3} $-B substrate interface
摘要： We investigated the structure of the Si(111)√3×√3-B surface and epitaxially grown Ag(111) film/Si(111)√3×√3-B substrate interface using surface X-ray diffraction. An analysis of their crystal truncation rod and fractional order rod scatterings revealed a good agreement between the structure of the Si(111)√3×√3-B surface and previous theoretical studies when taking into account structural inhomogeneity caused by subsurface defects. At the Ag film/Si(111)√3×√3-B substrate interface, the Si(111)√3×√3-B surface reconstruction was maintained intact. The experimentally determined positions of Ag atoms were displaced from the ideal Ag(111) bulk sites, and a 3×3 periodicity was introduced to the bottom layer of the Ag film at the interface. The 3×3 periodic corrugation was transferred, albeit damped, to the upper layer. This transfer was considered to be the origin of the 3×3 periodic pattern at the Ag film surface on the Si(111)√3×√3-B substrate, a pattern observed in our previous scanning tunneling microscope study.
关键词： crystal truncation rod,3×3 periodicity,surface X-ray diffraction,Si(111)√3×√3-B substrate,epitaxial growth,Ag film,fractional order rod,X-ray structural analysis
更新于2025-09-09 09:28:46
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Example-based image super-resolution via blur kernel estimation and variational reconstruction
摘要： Single image super-resolution aims at generating clear high-resolution image from one low-resolution image. Due to the limited low-resolution information, it is a challenging task to restore clear, artifacts-free image, meanwhile preserving finer structures and textures. This paper proposes an effective example-based image super-resolution method while making clear image and no compromise on quality. Firstly, the image prior is imposed on the anchor neighborhood regression model to optimize mapping coefficient for interim latent image construction. In order to remove its blur, kernel estimation iteration optimization algorithm is proposed based on the salient edges which are extracted through texture-structure discriminate minimum energy function and fractional order mask enhancement. Finally, an accurate reconstruction constraint combined with a simple gradient regularization is applied to reconstruct the super-resolution image. The proposed method is able to produce clear high-frequency texture details and maintain clean edges even under large scaling factors. Experimental results show that the proposed method performs well in visual effects and similarities. Furthermore, we test our algorithm in multi-texture images for robust evaluation. It is demonstrated that our algorithm is robust under complicated textures condition.
关键词： image reconstruction,super-resolution,fractional-order,blur kernel estimation
更新于2025-09-04 15:30:14