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- 저자 : Xiaojun Deng (검색결과 6 건)
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An Improved PSO Algorithm Based on Mutation Operator and Simulated Annealing
Xiaojun Deng,Zhiqiang Wen,Yu Wang,Pingan Xiang 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.10
Particle swarm optimization (PSO) algorithm is simple stochastic global optimization technique, but it exists unbalanced global and local search ability, slow convergence speed and solving accuracy. An improved simulated annealing (ISAM) algorithm is introduced into the PSO algorithm with crossover and Gauss mutation to propose an improved PSO (ISAMPSO) algorithm based on the mutation operator and simulated annealing in this paper. In the ISAMPSO algorithm, the mutation operator of genetic algorithm is introduced into the SA algorithm as a generation mechanism of new solution in order to propose an improved simulated annealing algorithm with mutation (ISAM). Then the ISAM algorithm is introduced into the PSO algorithm to jump out the local optimum, effectively achieve the global optimum adjust and optimize the population, maintain the diversity of the population, improve the local search ability and convergence speed. Six classical functions are selected to test the performance of the proposed ISAMPSO algorithm. The simulation experiments results show that the proposed ISAMPSO algorithm can effectively overcomes the stagnation phenomenon and enhance the global search ability. The convergence speed and accuracy were better than the PSO algorithm.
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A cam-quadrilateral mechanism for power transmission of a twin-rotor piston engine
Xiaojun Xu,Hao Deng,Cunyun Pan,Haijun Xu 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.3
A quadrilateral with four invariable lengths of sides has the characteristic of transforming the variation of the diagonal length to thevariation of its interior angle. Thus, the combination of two quadrilaterals with a cam forms the differential velocity drive mechanism(DVDM) of a novel twin-rotor piston engine (TRPE). The DVDM restricts the two coaxial rotors to rotate with periodical but nonuniformvelocity, and the volume of working chambers created by the adjacent vane pistons of the two rotors alternately expands and thencontracts. The volumetric change of working chambers is used to generate the four-stroke engine cycle. The kinematic model and thedetailed position, velocity, and acceleration analysis results of the TRPE are presented. The results show that this novel engine, associatedwith the advantages of higher uniformity of torque and power density due to multiple power strokes per revolution of the output shaft, hasa compact and totally balanced design.
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Near-Duplication Document Detection Using Weight One Permutation Hashing
Xinpan Yuan,Songlin Wang,Xiaojun Deng 한국정보과학회 2019 Journal of Computing Science and Engineering Vol.13 No.2
As a standard algorithm for efficiently calculating set similarity, Minwise hashing is widely used to detect text similarity. The major drawback associated with Minwise hashing is expensive preprocessing. One permutation hashing (OPH) is proposed in order to reduce the number of random permutations. OPH divides the space Ω evenly into k bins, and selects the smallest nonzero value in each bin to re-index the selected elements. We propose a weight one permutation hashing (WOPH) by dividing the entire space Ω into k1 and k2 bins and sampling k1 and k2 in proportion to form a weighted kw. WOPH has a wider range of precision by expanding the proportion of w1 and w2 to different accuracy levels of the user. The variance of WOPH can be rapidly decreased first and then slowly decreased, although the final variance is the same as OPH with the same k. We combined the dynamic double filter with WOPH to reduce the calculation time by eliminating unnecessary comparison in advance. For example, for a large number of real data with low similarity accompanied by high threshold queries, the filter reduces the comparison of WOPH by 85%.
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Hong Yue,Pingchuan Deng,Siyan Liu,Meng Wang,Weining Song,Xiaojun Nie 한국식물학회 2016 Journal of Plant Biology Vol.59 No.5
The appropriate reference genes are crucial for normalization of the target gene expression in qRT-PCR analysis. Broomcorn millet (Panicum miliaceum L.) is one of the most important crops in drought areas worldwide, while the systematical investigation and evaluation of reference genes has not been investigated in this species up to now. Here, 9 commonly used reference genes were selected to detect their expressional stability in different tissues and under different stresses in broomcorn millet. ΔC t , BestKeeper, NormFinder and GeNorm approaches were used to evaluate the potentiality of these candidate genes as the reference gene in broomcorn millet. Taken together, results found that 18S and GAPDH were the suitable reference genes for gene expression normalization in different tissues and under stress treatment in broomcorn millet. This was the first study to investigate the reference genes for qRT-PCR analysis in broomcorn millet, which will facilitate the gene expression studies and also accelerate revealing the molecular mechanism of well-adapted extreme climatic conditions.
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Development and Analysis of Negative Stiffness Friction Damping Device
Tianwei Sun,Lingyun Peng,Xiaojun Li,Yingjie Kang,Yuke Deng 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.7
A new type of negative stiffness friction damping device (NSFDD) was developed in this study, which can solve the problem of poor energy dissipation of the existing passive negative stiffness damping device. The friction force is generated by squeezing the friction plate with the preloaded nitrogen spring vertically. When the NSFDD is working, the friction plate causes the nitrogen spring to rotate and negative stiffness force and friction force are generated. The results of the performance test show that the NSFDD can achieve negative stiffness in the hysteretic model. Comparing with the existing negative stiffness device, the NSFDD has larger stroke, more stable negative stiffness and better energy dissipation capacity. The finite element software has been used to simulate the low cycle reciprocation of a structure, and the results show that the NSFDD reduces the stiffness of the structure while increasing the damping of the structure. The results of the simulation and analysis of the shock absorption plan of the NSFDD show that the NSFDD reduces the stiffness of the floor, thereby effectively control on the shear force, displacement and acceleration response of the structure.
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Stiffness modeling of a family of 6-DoF parallel mechanisms with three limbs based on screw theory
Bing Liang,Hongjian Yu,Zongquan Deng,Xiaojun Yang,Hong Hu 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1
The stiffness modeling of a family of six degrees of freedom (DoF) parallel mechanisms with configurations of 3-RUPU is presented. The mobility of the mechanisms is firstly analyzed, and then the stiffness analysis and modeling of the family of mechanisms is developed by a novel screw-theory based method. The method employs screw theory as a tool for force analysis and deformation analysis. Based on the developed stiffness model, two global flexibility indices, which refer to the maximum and minimum singular values of compliance matrix, are introduced to evaluate the compliance of parallel mechanisms. Finally, a case study is presented to demonstrate the effectiveness of the method in analyzing and evaluating the stiffness behavior of the presented parallel mechanisms.
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