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Adaptive learning algorithm based on mixture Gaussian background

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Journal of Systems Engineering and Electronics 2007年第2期18卷 369-376页

作者： Zha Yufei Bi Duyan Signal and Information Processing Lab Engineering Coll. of Air Force Engineering Univ. Xi'an 710038 P. R. China

The key problem of the adaptive mixture background model is that the parameters can adaptively change according to the input data. To address the problem, a new method is proposed. Firstly, the recursive equations are inferred based on the maximum likelihood rule. Secondly, the forgetting factor and learning rate factor are redefined, and their still more general formulations are obtained by analyzing their practical functions. Lastly, the convergence of the proposed algorithm is proved to enable the estimation converge to a local maximum of the data likelihood function according to the stochastic approximation theory. The experiments show that the proposed learning algorithm excels the formers both in converging rate and accuracy.

关键词： Mixture Gaussian model Background model, Learning algorithm.

Modified joint probabilistic data association with classification-aided for multitarget tracking

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Journal of Systems Engineering and Electronics 2008年第3期19卷 434-439页

作者： Ba Hongxin Cao Lei He Xinyi Cheng Qun air force command coll. Beijing 100097 P. R. China Inst. of command Automation PLA Univ. of Science & Technology Nanjing 210007 P. R. China Inst. of Combat Systems Naval Academy of Armament Beijing 100073 P. R. China Scientific Research Dept. PLA Univ. of Science & Technology Nanjing 210007 P. R. China

Joint probabilistic data association is an effective method for tracking multiple targets in clutter, but only the target kinematic information is used in measure-to-track association. If the kinematic likelihoods are similar for different closely spaced targets, there is ambiguity in using the kinematic information alone; the correct association probability will decrease in conventional joint probabilistic data association algorithm and track coalescence will occur easily. A modified algorithm of joint probabilistic data association with classification-aided is presented, which avoids track coalescence when tracking multiple neighboring targets. Firstly, an identification matrix is defined, which is used to simplify validation matrix to decrease computational complexity. Then, target class information is integrated into the data association process. Performance comparisons with and without the use of class information in JPDA are presented on multiple closely spaced maneuvering targets tracking problem. Simulation results quantify the benefits of classification-aided JPDA for improved multiple targets tracking, especially in the presence of association uncertainty in the kinematic measurement and target maneuvering. Simulation results indicate that the algorithm is valid.

关键词： multi-target tracking data association joint probabilistic data association classification information,track coalescence maneuvering target.

Improved hybrid position/force controller design of a flexible robot manipulator using a sliding observer

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Journal of Systems Engineering and Electronics 2009年第1期20卷 146-158页

作者： Farooq M Wang Daobo Dar N. U coll. of Automation Engineering Nanjing Univ. of Aeronautics & Astronautics Nanjing 210016 P. R. China coll. of Mechanical Engineering Univ. of Engineering and Technology Taxila Pakistan

An improved hybrid position/force controller design of a flexible robot manipulator is presented using a sliding observer. The friction between the end effector and the environment is considered and compensated. For systematic reasons the controller is designed taking into consideration the rigid link subsystems and the flexible joints. The proposed control system satisfies the stability of the two subsystems and copes with the uncertainty of robot dynamics. A sliding observer is designed to estimate the time derivative of the torque applied as input to the rigid part of the robot. For the stability of the observer, it is assumed that the uncertainty of the observed system is bounded. A MRAC algorithm is used for the estimation of the friction forces at the contact point between the end effector and the environment. Finally simulation and experimental results are given, to demonstrate the effectiveness of the proposed controller.

关键词： force control sliding control Lyapunov stability robot end effector friction force.

Relationship between Beating and Setting-on Place

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Journal of China Textile University(English Edition) 2000年第3期17卷 39-42页

作者：张志奋朱苏康 coll. of Textiles China Textile Univ. Shanghai 200051 China

In this paper,what causes the setting-on place of woven fabrics without adopting tension compensation is explained by means of experimental *** to that the main shaft speed and the beating speed of reed can not attain the normal values at setting-on,the warp tension and the beating force of the reed can neither reach the normal ***,the relative slippage movement of the weft against the warp during beating will be less,while the common movement of the weft together with the warp will be bigger than those at nor-mal *** a result,the setting-on place is

关键词： loom fabric setting - on place beating speed main shaft speed.

Preliminary Study on Anti-Dropping Methods for Short Cashmere Woolen Cloth

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Journal of China Textile University(English Edition) 2000年第4期17卷 87-89页

作者：陆凯郁崇文 coll. of Textiles China Textile Univ. Shanghai 200051 China

The fibre dropping mechanism of short cashmere fabrics is elucidated. Results show that to reduce the fibre dropping, it is necessary to increase the linkage force among the fibers, and the special anti - dropping finishing for the fabrics which have been normally finished, should be carried out. To evaluate the six selected anti - dropping finishing agents, fuzzy judgment method was used, and the agent, with the most effect on anti - dropping, was found out.

关键词： short cashmere anti-dropping fuzzy judgment

In-situ A1/24Si Functional Graded Materials Prepared by Electromagnetic Separation

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Journal of Materials Science & Technology 2002年第5期18卷 385-386页

作者： KeLI JunWANG DaSHU BaodeSUN YaoheZHOU coll. of Mat. Sci. and Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

Cylinder-like in-situ AI/24Si FGMs were produced by using electromagnetic separating process. Si primary phase reinforced layer with volume fraction as high as 16 pct was formed at the outer region of the cylinder-like samples where the local hardness and wear resistance were enhanced remarkably. Moreover, both of strength and ductility in the inner region provided insurance of reliable strength for this as-cast gradient material. It indicated that general mechanical properties such as good wear resistance at the outer region and good ductility in the central part could be obtained with the optimized redistribution of the Si primary particles under the electromagnetic force.

关键词： FGMs In-situ Electromagnetic separation

Robust power amplifier predistorter by using memory polynomials

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Journal of Systems Engineering and Electronics 2009年第4期20卷 700-705页

作者： Li Bo Ge Jianhua Ai Bo State Key Lab. of Integrated Service Networks Xidian Univ. Xi'an 710071 P. R. China School of Information Engineering Chang'an Univ. Xi'an 710064 P. R. China Engineering coll. of Armed Police force Xi'an 710086 P. R. China

In memory polynomial predistorter design, the coefficient estimation algorithm based on normalized least mean square is sensitive to initialization parameters. A predistorter based on generalized normalized gradient descent algorithm is proposed. The merit of the GNGD algorithm is that its learning rate provides compensation for the independent assumptions in the derivation of NLMS, thus its stability is improved. Computer simulation shows that the proposed predistorter is very robust. It can overcome the sensitivity of initialization parameters and get a better linearization performance.

关键词： power amplifier predistortion memory polynomial generalized normalized gradient descent orthogonal frequency division multiplexing.

THEORETICAL PREDICTION OF PROEUTECTOID FERRITICTRANSFORMATION IN HYPO-PROEUTECTOID STRUCTRAL STEELS

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Acta Metallurgica Sinica(English Letters) 1998年第3期11卷 207-214页

作者： H.B.Chang Z.G.Li T.Y.Hsu Z.Y.Xu X.Y.Ruan Shanghai Technical coll.of Metallurgy Shanghai China

Proeutectoid ferrite with carbon content xo precipitating from austenite in a multicomponent steel at temperature T is supposed to be equivalent to proeutectoid ferrite with the same carbon content precipitating from austenite in Fe-C binary system at temperature T'.is described as the temperature difference of proeutectiod ferrite formation, and can be calculated from the Fe-X diagrams and the equilibrium temperature A3. By introducing Tf and basing on the thermodynamic model for Fe-C binary alloy, the driving force for phase transformation from austenite to proeutectoid ferrite in multicomponent steels has been successfully calculated. Through the Johnson-Mehl equation and using the data hem known TTT diagrams, the relationship between the chemical composition and the intedecial edenly packeter as well as activation energy for proeutectoid ferrite formation can be calculated. The starting curves of proeutectoid ferritic transformation calculated in this way in some hypo-proeutectoid structural steels agree well with the erperimental data.

关键词： proeutectoid ferrite formation temperature difference interfacial enerpy parameters activation energy for diffusion Johnson-Mehl equation

SYNTHESIS OF PERFLUORO-1-OCTANESULFONATED FULLERENE AND THE FRICTION PROPERTIES OF ITS THIN FILM

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Chinese Journal of Polymer Science 2002年第5期20卷 397-400页

作者： Lan Huang Shuang Fan Fang Wei Xin-sheng Zhao Jin-xin Xiao Bu-yao Zhu coll.ge of Chemistry and Molecular Engineering Peking University Beijing 100871, China Peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China

A star-shaped compound of perfluoro-1-octanesulfonated fullerene was synthesized. The measurement of the friction for its spin-coating film by friction force microscopy (FFM) reveals that the films possess lower frict... 详细信息

关键词： perfluoro-1-octanesulfonated fullerene thin film friction force microscopy (FFM)