Papers by Keyword: Discretization

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Authors: Xiao Kang Tang, Xue Zhi Zhang, Qiong Zou, You Guo Wei, Cheng Jun Cao
Abstract: when the rough set be used to deal with Knowledge representation system, the data in decision table should be expressed in discrete data, if some conditions or decision attribute is continuous value, which should be discrete Before process.Discretization is not specific data processing only by rough set theory , people have conducted extensive research on discretization problem before the rough set theory put forward , and Made a lot of progress ,but the discretization technique is can not be completely in common used in every subject, different areas have their own unique requirements and handling .This paper proposes a discretization algorithm based on regular conditional entropy.
Authors: Guo Qiang Sun, Hong Li Wang, Jing Hui Lu, Xing He
Abstract: Rough set theory is mainly used for analysing, processing fuzzy and uncertain information and knowledge, but most of data that we usually gain are continuous data, rough set theory can pretreat these data and can gain satisfied discretization results. So, discretization of continuous attributes is an important part of rough set theory. Field Programmable Gate Array(FPGA) has been became the mainly platforms that realized design of digital system. In order to improve processing speed of discretization, this paper proposed a FPGA-based discretization algorithm of continuous attributes in rough ret that make use of the speed advantage of FPGA and combined attributes dependency degree. This method could save much time of pretreatment in rough ret and improve operation efficiency.
Authors: Zhao Hui Ren, Yuan Hao, Bang Chun Wen
Abstract: Continuous attribute discretization based on rough set is to got possibly minimum number of cuts, and at the same time it should not weaken the indiscernibility ability of the original decision system. In order to obtain the optimal cut set of the continuous attribute system, based on research the choice of candidate cut set, this paper presents a heuristic genetic algorithm for continuous attribute discretization to decision tables. In this algorithm making the importance of the continuous cut as heuristic message, a new operator is constructed to not only maintain the discernibility of the cuts selected, but also improve local search ability of the algorithm. Compared the performance of this method with the others’, this method is proved effective and superiority.
Authors: Zhong Yi Cai, Mi Wang, Chao Jie Che
Abstract: A new stretch-forming process based on discretely loading for three-dimensional sheet metal part is proposed and numerically investigated. The gripping jaw in traditional stretch-forming process is replaced by the discrete array of loading units, and the stretching load is applied at discrete points on the two ends of sheet metal. By controlling the loading trajectory at the each discrete point, an optimal stretch-forming process can be realized. The numerical results on the new stretch-forming process of a saddle-shaped sheet metal part show that the distribution of the deformation on the formed surface of new process is more uniform than that of traditional stretch-forming, and the forming defects can be avoided and better forming quality will be obtained.
Authors: Rohit Tripathy, Sadhana Mishra, R. Thundil Karuppa Raj
Abstract: The performance of an Earth-Air Heat Exchanger (EAHE) system to be operated in climatic and soil conditions prevailing in the Indian district of Nagpur is modeled numerically. To do so, a CFD model is developed in ANSYS Fluent 12.1. The validation of the CFD model is carried out using data obtained from published literature and good agreement is established between the simulation results and published experimental data. An earth pipe of length 60 m and internal diameter 0.1 m is chosen for validating the model and this validated model is used to further investigate for three different lengths of the pipe - 40 m, 35 m and 30 m. The 3-dimensional flow field through the earth air heat exchanger is studied numerically by solving the appropriate governing equations namely: continuity, momentum and energy equations and a finite volume CFD code is employed for solving the same. An air inlet velocity of 2 m/s is maintained and the inlet temperature was varied between 308.1 K and 315 K for each chosen length. The decrease in temperature and flow distribution along the pipe length is plotted.
Authors: Jing Zhao, Chong Zhao Han, Bin Wei, De Qiang Han
Abstract: Discretization of continuous attributes have played an important role in machine learning and data mining. They can not only improve the performance of the classifier, but also reduce the space of the storage. Univariate Marginal Distribution Algorithm is a modified Evolutionary Algorithms, which has some advantages over classical Evolutionary Algorithms such as the fast convergence speed and few parameters need to be tuned. In this paper, we proposed a bottom-up, global, dynamic, and supervised discretization method on the basis of Univariate Marginal Distribution Algorithm.The experimental results showed that the proposed method could effectively improve the accuracy of classifier.
Authors: Jun Hu, Fan Deng, Xian Chen Qiu
Abstract: This paper proposed an optimized algorithm for discretization of cutter location points on the laser cutting path of three-dimensional surface. The initial discretization step size was calculated due to the curvature of the curve on the starting point and accuracy requirements. A reference sphere was established by taking the initial discretization step size as the radius. The initial cutter location point was located on the intersection of the reference sphere and the processing path. The radius of reference sphere was dynamically adjusted by dichotomy according to string height difference in order to get the optimal cutter location on the path to be processed. This algorithm has a high computational efficiency. And an automatic programming software used for three-dimensional laser cutting was developed based on this algorithm.
Authors: Andrei Craifaleanu, Nicolaie Orăşanu, Cristian Dragomirescu
Abstract: The study of the bending vibrations of Euler-Bernoulli beams is typically performed based on pure elastic material models, which neglect the damping. However, in practice, due to the internal friction of the material, the vibrations are damped. This phenomenon can be taken into account by using a viscoelastic material model, in which supplementary strains, dependent on the strain rates, are considered. In the paper, free bending vibrations of homogeneous viscoelastic Euler-Bernoulli beams are studied by developing generalized forms of an exact and of an approximate method, respectively, used regularly in the study of pure elastic Euler-Bernoulli beams. The developed methods are applied and compared on a numerical example, highlighting their advantages and limitations.
Authors: Yuan Liang Zhang
Abstract: In this paper, a new discretization method to obtain the sampled data representation of the nonlinear state delay control system is proposed. This discretization method is based on the matrix exponential computation. The mathematical structure of the new discretization scheme is explored. Then it is applied to obtain the discrete form of the nonlinear state delay continuous systems. The resulting time discretization method provides a finite dimensional representation for nonlinear control systems with state delay, thereby enabling the application of existing controller design techniques to such systems. The performance of the proposed discretization procedure is evaluated by means of the simulation study. In the simulation various sampling rates and time delay values are considered. The results demonstrate that the proposed discretization scheme can assure the system’s accuracy requirements.
Authors: Jie Ning Xia, Zhi Gao Chen, Jian Yang, Peng Wu
Abstract: Based on the original CAV formula definition given by the electric power research institute in the United States, the continuous integral formula is discretized so that it can be better applicable to the actual application requirements, and also the shaded area calculation method necessary in the process of calculation is further proposed. Finally, this algorithm is implemented with LAVIEW program, and also the simulation data and the CAV calculation result of the real Lushan earthquake acceleration data were given so that the algorithm was fully validated, and also a solid foundation was further laid for the deeper CAV-related parameter study.
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