Papers by Keyword: Fractal

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Authors: Xu Dong Xu, Jing Qing Ye, Guan Feng Lv
Abstract: In this paper, we propose a 3D tree simulation method which is based on fractal theory and combined with the morphological characteristics of trees. By modifying a few simple parameters we can achieve the realization of different types of 3D tree automated generation. According to the tree structure fractal self-similar characteristic, combined with the morphological characteristics of the trees, we abstract identified class to realize the description of each organs attributes and functions; Using random control function to improve the fractal iterative methods to make the generated trees more realistic; With the help of the developing platform of Visual C++ language and OpenGL, we can realize 3DTrees optimize modeling and visualization simulation. Experiments show that the method generates visually convincing results.
Authors: Yuan Luo, Yuan Liu
Abstract: The Digital Speckle Correlation Method is a non-contact in-plane displacement measurement method based on machine vision. The spline, the linear or the bi-cubic interpolation algorithm is often used in the sub-pixel algorithm. The block effect or the edges blurring, however, could occur in these algorithms. Therefore, a fast interpolation algorithm based on fractal theory is proposed in this paper. The results indicate that this algorithm can overcome either the blocking effect or the edge blurring caused by the traditional interpolation algorithm. In addition, with the same sub-pixel accuracy, the shortest time is required.
Authors: Shao Ping Zhou, Quan Yuan, Xiao Ling Ge, Pei Ning Li
Abstract: The sedimentation in the field of gravity provides a practicable and scientific principle for solid-liquid separation of ultra-fine particles. According to the fractal theory, a model of ultra-fine particles for gravity sedimentation was developed, considering the aggregation effects and particles interference, and the aggregation promoting coefficient was put forward. The fractal structure and FSD of aggregates were also analyzed. Furthermore, the comparison between theoretical and experimental values of ultra-fine particles sedimentation showed that the two results were more consistent with each other for the suspension concentration ranging from 1 wt% to 5 wt%.
Authors: Xiao Hong Qiu, Bo Li, Zhi Yong Cui, Jing Li
Abstract: To get better solution by improving the mutation strategy of Differential Evolution algorithm, a fractal mutation strategy is introduced. The fractal mutation factor of the proposed Fractal Mutation factor Differential Evolution (FMDE) algorithm is simulated by fractal Brownian motion with a different Hurst index. The new algorithm is test on 25 benchmark functions presented at 2005 IEEE Congress on Evolutionary Computation (CEC2005). The optimization results of at least 10 benchmark functions are significantly better than the results obtained by JADE and CoDE, and most of the rest of the test results are approximate. This shows that FMDE can significantly improve the accuracy and adaptability to solve optimization problems.
Authors: Yun Fu Chen
Abstract: For finding influence of the condensing surface to dropwise condensation heat transfer, a fractal model for dropwise condensation heat transfer has been established based on the self-similarity characteristics of droplet growth at various magnifications on condensing surfaces with considering influence of contact angle to heat transfer. It has been shown based on the proposed fractal model that the area fraction of drops decreases with contact angle increase under the same sub-cooled temperature; Varying the contact angle changes the drop distribution; higher the contact angle, lower the departing droplet size and large number density of small droplets; dropwise condensation translates easily to the filmwise condensation at the small contact angle ;the heat flux increases with the sub-cooled temperature increases, and the greater of contact angle, the more heat flux increases slowly.
Authors: Jie Xu, Giusepe Lacidogna
Abstract: A fractal is a property of self-similarity, each small part of the fractal object is similar to the whole body. The traditional box-counting method (TBCM) to estimate fractal dimension can not reflect the self-similar property of the fractal and leads to two major problems, the border effect and noninteger values of box size. The modified box-counting method (MBCM), proposed in this study, not only eliminate the shortcomings of the TBCM, but also reflects the physical meaning about the self-similar of the fractal. The applications of MBCM shows a good estimation compared with the theoretical ones, which the biggest difference is smaller than 5%.
Authors: Hong Chan Zheng, Yi Li, Guo Hua Peng, Ya Ning Tang
Abstract: In this paper, we firstly devise a p-ary subdivision scheme based on normal vectors with multi-parameters to generate fractals. The method is easy to use and effective in generating fractals since the values of the parameters and the directions of normal vectors can be designed freely to control the shape of generated fractals. Secondly, we illustrate the technique with some design results of fractal generation and the corresponding fractal examples from the point of view of visualization. Finally, some fractal properties of the limit of the presented subdivision scheme are described from the point of view of theoretical analysis.
Authors: Sanaz Shahraeini, Mahdi Yaghoobi
Abstract: The recent progress in the digital multimedia technologies has offered many facilities in the transmission, reproduction and manipulation of data. However, this advance has also brought the problem such as copyright protection for content providers. Digital watermarking is one of the proposed solutions for copyright protection of multimedia. This paper proposes a blind watermarking algorithm based on fractal model in discrete wavelet domain for copyright protection. The idea of the presented scheme is to hide a binary image as a watermark with fractal parameters in wavelet domain of host image. Fractal compression technique is used to encode a gray image and fractal codes are embedded into the wavelet coefficients of the gray image according to well-connected watermark algorithm. The experimental results show that the algorithm is robust against geometric and non geometric attacks.
Authors: Asma A. Shariff, M. Hadi Hafezi
Abstract: The objective of this paper is to consider the use of fractal geometry as a tool for the study of non-smooth and discontinuous objects for which Euclidean coordinate is not able to fully describe their shapes. We categorized the methods for computing fractal dimension with a discussion into that. We guide readers up to the point they can dig into the literature, but with more advanced methods that researchers are developing. Considerations show that is necessary to understand the numerous theoretical and experimental results concerning searching of the conformality before evaluating the fractal dimension to our own objects. We suggested examining a cloud of points of growth of fracture surface at laboratory using CATIA - Digitized Shape Editor software in order to reconstruct the surface (CAD model). Then, the author carried out measurement/calculation of more accurate fractal dimension which are introduced by [1] in the other paper as Part II.
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